Adaptation to living with a stoma is complex, and studies have shown that stoma creation has a great impact on patients' health related quality of life. The objective was to explore the effect of a structured patient education program on health related quality of life. Therefore, we implemented interventions aimed at increasing health related quality of life during and after hospital admission.We designed a case/control study aimed at adult patients admitted to the surgical ward for stoma creation, irrespective of type of stoma or reason for creation of stoma. We included 50 patients in the study. Health related quality of life was measured before hospital discharge, three months and six months after stoma creation. The program included educational interventions involving lay-teachers, alongside health professional teachers.p = 0.12 and p =  0.63, respective). Additionally, there were differences in scores in health related quality of life baseline (p = 0.045) with lower scores in the intervention group compared with the intervention group. However, there were no significant differences in the demographic variables at baselineWe found a significant rise in health related quality of life in the intervention group (P<0.001) and no significant change in the control group (P = 0.144). However, we found no significant differences when comparing between groups at 3 and 6 months (Educational activities aimed at increase in knowledge and focusing on patients' psychosocial needs may lead to a rise in patients' health related quality of life. When patients with a stoma attend a structured patient education program it is possible to improve their health related quality of life compared with patients with a stoma, who do not attend the program.NCT01154725ClinicalTrials.gov  Stoma creation affects patients differently A previous study has shown that appropriate patient education in the preoperative period may reduce time until proficiency in stoma handling, as well as time until discharge from hospital Therefore, we designed a clinical study exploring the effect of structured patient education in patients after stoma creation. We hypothesized that patient education and telephone follow-up would affect treatment outcome of health related quality of life (hrqol).We designed a case-control study including patients admitted to the surgical department for stoma creation. Patients were included from August 2010 until June 2011 with a follow-up period of 6 months after surgery. The inclusion was sequential. First we included and studied the control group receiving routine stoma care, and subsequently the intervention was implemented and the intervention group was included.We obtained an informed oral and written consent from all participants included in this study. The protocol for this trail and supporting CONSORT checklist are available as supporting information; see The main objective of the study was to explore whether the interventions would improve hrqol 6 months after stoma creation. We applied the questionnaires Ostomy Adjustment Scale (OAS) and Short Form 36 (SF-36), and patients were scored three times: a few days before discharge, and three months and six months after discharge.Furthermore, we explored the costs related to the implementation of the patient education program, and the results are reported elsewhere The primary outcome was hrqol measured by OAS 6 months after stoma creation. In the literature we found no data for OAS measured 6 months after surgery. However, there were data describing means and standard deviations for outcome measured from 1 to 30 years after surgery We included adult patients (18 years+) admitted to the surgical department after stoma creation no matter whether the stoma was a colostomy or an ileostomy, irrespective of whether it was expected to be permanent or temporary, and regardless of reason for creation of the stoma.Patients, who withdrew their consent to participate.Patients admitted to the surgical department for a planned stoma creation received preoperative education by the stoma therapist. Patients operated on an acute basis did not meet the enterostoma therapist (ET) before 4–5 days after stoma creation, just before leaving hospital. The preoperative education in the elective setting included information on stoma care, and marking of the stoma site on the patient's abdomen. After surgery, the patient would be guided by the nurses in the surgical ward regarding stoma care. The ET had a discharge dialogue with the patient before leaving hospital, and once at home, the patient had scheduled contacts with the ET at 10 days, 1 month, 3 months, 6 months, and 12 months after stoma creation. Furthermore, patients would have access to contact with the out-patient clinic by telephone.The intervention group received the same interventions as the control group. Additionally, patients in the intervention group were visited in the ward by the ET two (+/- 1) days after stoma creation. The visit was set up to guide and supervise the patient when changing the pouch, often for the first time. Furthermore, the ET would prepare a plan for the clinical care of the patient to guide the patient as well as the ward nurses. The visit was guided by a checklist developed by the first author.Furthermore, the ET contacted the patient by telephone 5 (+/- 2) days after discharge, and assessed the patient's well-being following a checklist. Questions related to stoma care were resolved, and any need for face-to-face visits at the stoma clinic was examined by the ET.Patient education sessions were set up after hospital discharge and were organized according to issues that were identified as relevant and central for patients after stoma creation Hrqol was assessed before leaving hospital, 3, and 6 months after stoma creation. As a disease-specific quality of life measurement the Ostomy Adjustment Scale (OAS) was used to assess the disease-specific adjustments Short form 36 v2 was a generic tool evaluating quality of life from patients' self-reports on different conditions influencing quality of life p≤0.05. Furthermore, we performed a missing data analysis using binary logistic regression. The plan for analysis was based on an intention-to-treat strategy.Data analysis was based on descriptive statistics and nonparametric tests using IBM SPSS statistics version 20. Descriptive data were reported as median with range. Comparisons between or within groups or between groups were made using Fisher's exact test, Friedmańs test, and Mann Whitney test where applicable. Statistical significance was set at www.clinicaltrials.gov (NCT01154725).Approval of the study was obtained from the Danish data protection agency (J.nr. 2010-41-4706). The study was performed in compliance with the ethical principles of the World Medical Association declaration of Helsinki. However, the Danish Regional committee evaluated that the study was exempt from approval because we aimed at quality assurance rather than performing a biomedical intervention (H-2-2010-041). Furthermore, the study was notified on p<0.05, p = 0.38 at the third visit, 6 months after stoma creation). Furthermore, we performed a binary logistic regression analysis to explore whether gender, cancer/non-cancer, and outcome were significantly related to the dropout of participants, showing no difference between dropouts and patients still in the study . We did not use an intention-to-treat analysis as we experienced missing of data. However, all participants were analyzed within the group to which they were originally allocated.Of the 280 eligible participants 75 were invited to participate. 25 of these declined and we included 25 patients in each group . After tp = 0.14, p = 0.045) between the groups with lower scores in the intervention group (score 122) compared with the intervention group (score 134). Moreover, there were no significant differences between groups 3 and 6 months after stoma creation .The intervention group showed a significant development in OAS scores between baseline, three months and 6 months , and mental health (p = 0.02). In the intervention group there were significant changes in bodily pain (p = 0.004) and mental health (p = 0.04). None of the other dimensions of health showed significant variation throughout the study period .We found significant changes in the control group in physical functioning (P = 0.001), bodily pain  the improvements were only significant in some of the profiles. However, there were no differences between groups in OAS or SF-36 at 6 months after stoma creation.The differences at baseline in scores on OAS might be because of a systematic inclusion bias, where we have included patients in the intervention group, who were characterized by lower hrqol scores. When looking at the demographic data at baseline, we were not able to detect significant differences , nor werPrevious studies have explored the impact of patient educational activities directed towards patients with a stoma However, the results of our study might add to the results of two interventional single-group studies aimed at exploring the effect of patient education on health related quality of life Other studies have suggested that patient education related to patients with a stoma should focus more on socially oriented elements The differences when using different questionnaires probably reflected that the OAS, being a disease-specific questionnaire, was more sensitive to the stoma related problems that the patients perceived. SF 36 is a generic questionnaire and was obviously not as sensitive to the changes and the feelings experienced by the patients in our study.The results of this study may have been influenced by the drop-out rate and therefore a loss of data. Furthermore, the inclusion rate was low, as the researcher did the inclusion on her own, and is a well known difficulty when doing clinical research In conclusion, we have shown that establishment of a structured patient education program aimed at patients with a stoma improved disease specific areas within health related quality of life. A program including interventions aimed at increasing knowledge as well as self-management might benefit from including lay-teachers alongside health professional teachers. Furthermore, the use of telephone follow-up after discharge from hospital may increase patients' health related quality of life.Protocol S1Trial Protocol.(PDF)Click here for additional data file.Checklist S1CONSORT Checklist.(PDF)Click here for additional data file.


C-reactive Protein (CRP) is used next to clinical scoring systems to recognize critically ill patients prone to develop complications on the Intensive Care Unit (ICU). The purpose of this study is to assess the predictive value of CRP as parameter for clinical deterioration and/or clinical decision making as ordering diagnostic procedures or performing (re)interventions. Also, we wanted to determine the value of CRP in early detection of surgical complications in the critically ill general surgical patient in the ICU and its interpretation in adjunct to a clinical scoring system, the Sequential Organ Failure Assessment Score.In our prospective observational study, 174 general surgical patients admitted into the Intensive Care Unit were included. We evaluated the Sequential Organ Failure Assessment Score (SOFA) and daily measured the C-reactive protein (CRP) concentrations. All events (diagnostic or therapeutic interventions) and surgical complications were registered. Then the relationship between SOFA score, CRP concentrations, events and complications were studied.p = 0.028). However, an increase in CRP levels did not lead to a higher odds of complication . When adjusting for the SOFA score the effect of CRP on the probability of a first event remained significant , and again did not significantly affect the complication probability .Each 10% increase in CRP resulted in a 3.5% increase in the odds of an event -interventions. C-reactive protein (CRP) is an acute phase protein synthesized by the liver, which levels raise in response to inflammation. It is a sensitive but non-specific inflammatory biomarker often used as an indicator for systemic inflammatory response syndrome (SIRS) Many classification systems have been developed to recognize early deterioration in critically ill patients. An important scoring system is the Sequential Organ Failure Assessment Score (SOFA score) which describe the clinical course of the patient as marker for the degree of organ dysfunction and predictor for mortality Next to the clinical scoring systems, other conventional markers are used to recognize these specific patients who are prone to develop complications, for example CRP. Studies about the value of CRP in the critically ill patient on the ICU are contradictory. Increased CRP concentrations in a heterogeneous population on the ICU have been associated with organ failure, prolonged ICU stay, high infection rates and mortality rates Despite contradictory studies, trends in CRP concentrations during the ICU admission are frequently used to determine whether or not further, more invasive, diagnostic procedures and/or therapeutic interventions are required. An increase in CRP levels has been described as a crucial indicator for the diagnosis of postoperative complications in surgical patients such as infection, SIRS, sepsis, anastomotic leakage or mesenterial ischemia The purpose of this study is to assess the predictive value of CRP concentrations as parameter for clinical deterioration and/or clinical decision making as ordering diagnostic and therapeutic (re)interventions in a heterogeneous group of surgical patient on the ICU. Furthermore, we wanted to determine the value of CRP in detection of surgical complication in the critically ill surgical patient in the ICU and its interpretation in adjunct to a clinical scoring system, the SOFA score.All surgical patients, admitted to the level three general surgical Intensive Care Unit at the Amphia hospital Breda, a tertiary health care institute, were prospectively included into the study when inclusion and exclusion criteria were fulfilled. Data were collected from April 2010 until June 2011. Inclusion was regardless of the indication for admission. The study was approved by the Institutional Review Board of the Amphia Academy Breda and the need for informed consent was waived.Exclusion criteria were defined as non-surgical patients or cardiac surgery patients, duration of stay shorter than two days and patients younger than 18 years of age at time of admission into the ICU. The duration of follow-up was until the day of discharge or set at a maximum of 28 days. In case that more than one ICU-episode was observed within the same patient, only the first episode was chosen in order to meet the assumption of independence of observations.Patient characteristics, initial surgery type and diagnosis for admission into the ICU were collected. Definition for systemic inflammatory response syndrome (SIRS) and sepsis, as described by Bone All patients admitted into the ICU underwent standard care, including daily routine laboratory tests (with CRP concentrations) and a plain chest X-ray. Prophylaxis for ventilator-associated pneumonia was started when a duration of stay of 72 hour or longer was expected and/or mechanical ventilation for more than 48 hours was started (SDD). This prophylaxis included Cefotaxim 1 gram 4 times daily continued for four days and Orabase protective paste 4 times daily applied in the mouth and administered through a nasogastric tube.Routine laboratory tests (hematology and biochemistry) were taken for all patients admitted into the ICU as part of the standard care. CRP concentrations were quantified using particle-enhanced immunologic turbimetric measurement for C-reactive protein Gen 3 in serum, as described by Roche .The Sequential Organ Failure Assessment Score (SOFA score) was used as a marker for organ dysfunction over time in patients on the Intensive Care Unit. This simple scoring system daily assigns 1 to 4 points to each of the six organ systems examined depending on the level of dysfunction. The tracts used in this scoring system are pulmonary, cardiovascular, coagulation function, hepatic, renal and neurological  [4].To calculate the value of CRP and SOFA score in clinical decision making, we defined the following interventions as events: CT-scan, ultrasonography (with or without punction), and flexible endoscopy or (re) laparotomy/thoracotomy. When surgical complications were found during these interventions, the events were defined as positive. Surgical complications were defined as intra-abdominal abscesses, anastomotic leakage, mesenterial ischemia, ileus, perforations, bleeding, diaphragm rupture or pneumothorax. Other non-surgical complications were also registered if present.The treating physicians were not blinded for CRP nor SOFA score in order to reflect actual practice on the ICU. In addition, the majority of the treating physicians was not involved, nor participated in the design, purpose and methods of the study.The number of historical ICU-episodes to be retrieved in this observational study is determined by the smallest group: the number of complication as proportion of the number of events to be predicted by two consecutive CRP measurement and SOFA measurements. Based on the rule of thumb that in logistic regression analysis the size of the smaller group should be at least ten times the number of variables in the model, the number of historical ICU episodes to be retrieved and the number of events should be large enough to yield at least 40 complications. We anticipated that 40 complications would result from 100 first events which in its turn would result from 200 ICU-episodes.Results are presented as means ± standard deviation for continuous variables that have a Gaussian-shaped distribution and as (relative) frequencies for categorical nominal variables. When comparing two groups, the Chi-square test was used for categorical nominal variables and the unpaired T-test for continuous variables.The relationship between the observation that an event had taken place and the preceding levels or changes of CRP was analyzed in a case-cohort design using conditional logistic regression analysis. Time was measured as days since admission to the ICU. For each day that an event occurred, the last and next to last CRP measurements were compared between patients with an event (the cases) and patients without an event on that same day (the remaining cohort). This comparison was made by using conditional logistic regression analysis. In this analysis the data were stratified by event-day, providing an optimal adjustment for day since admission when estimating the simultaneous effect of level and change of CRP on the event probability. Only the first occurring event within a patient was involved in this analysis so that events can be considered as mutual independent outcomes.CRP-measurements were logarithmically transformed before analysis because of their positive skewness. The difference and sum of both measurements were entered in the model, respectively standing for the simultaneous effect of CRP-change and CRP-level on the event probability.Directly after an event had taken place in a patient, additional investigations were done to confirm the event. So, in all ICU-patients in whom a first event had taken place a second outcome variable was observed: confirmation (yes or no). That outcome variable was analyzed using ordinary logistic regression analysis with the same explanatory CRP-variables as in the conditional regression analysis for explaining event (yes/no).Prior to the above described  logistic regression analyses we analyzed the dependency of CRP on ICU-day (a maximum of 28 days) and event (yes/no) using linear mixed modelling. The first aim was to estimate the mean difference in CRP between events and no events across all 28 days (at maximum) and across all subjects in the total ICU-cohort, while correcting for the categorical day-effect on CRP. In this analysis all events within a patient were taken into account by considering event (yes/no) a time-dependent within-patient explanatory factor equal to 1 at ICU-days that an event occurred and 0 at other ICU-days. The variance-covariance structure of the repeated CRP measurements across ICU-days was assumed to be first-order autoregressive with heterogeneous variances. A similar analysis was done for the effect on complication (yes/no). The second aim was to analyze the dependency of CRP levels on the SOFA score entered in the linear mixed model.P-value below 0.05 was considered to indicate statistical significance.Statistical analysis was performed using SPSS 15.0, GraphPad Prism 5.0 for Windows and EGRET. A two sided A total 174 patients were included in the study with 198 ICU-episodes. Four patients had three ICU-episodes, 16 patients had two ICU-episodes and 154 had one ICU episode. At time of admission into the ICU, the mean age of our patient population was 72 years . Postoperative SIRS and sepsis were the main indications for admission in 45% (n = 78) of all patients. Most patients admitted into the ICU had undergone an emergency laparotomy for an acute abdomen or a re-exploration for complication of previous surgery . Further baseline characteristics between patients with and without events are showed in p = 0.003). No significant difference in APACHE II score was seen between patients with and without complications .The mean Acute Physiology and Chronic Health Evaluation II score on admission was 21±9 points (min 8 - max 49 points). Patients with an event had significant higher scores than those without an event . Patients with and without complications had a small, non-significant difference in mortality . The main cause of death was multi organ failure.Overall in-hospital mortality on the ICU in our patient group was 9.8% (17/174). A higher mortality rate was observed in patients who underwent an event compared to those without an event  of the 174 patients admitted into the ICU had an event of which twenty-four underwent more than one intervention. A total of 117 events were identified of which 50 (43%) were CT-scans in 30 patients and 32 (27%) re-operations in 23 patients . In 48% One-hundred and seventeen events occurred in 77 of the 174 patients admitted into the ICU. Of these 117 events, 67 (46/77 patients) were involved with a complication. The most common complications that we found were intra-abdominal abscesses  followed by mesenterial ischemia  . Non-surp = 0.39). Furthermore, patients with and without complications had no difference in SOFA scores either . On the other hand, a significant log-linear relationship between SOFA score and CRP concentrations was found using linear mixes modeling. A one point increase in SOFA score corresponded with a 7.2% increase in CRP levels (95% CI: 5.3%–9.0% p<0.0005).The Sequential Organ Failure Assessment Score varied between 0 and 16 points. At admission a mean SOFA score of 5.2±2.6 points was found, which peaked at day two (5.6±2.7 points). After this peak, the mean SOFA score decreased over time. No significantly different SOFA score was observed between patients with and without an event . After this peak the CRP concentrations started to decrease to normal levels (p = 0.040). No significant difference in CRP levels was seen when comparing patients with a complications and without a complication on the same day . In these analyses linear mixed modeling accounted for all available daily repeated CRP measurements within patients during the ICU stay.The overall mean CRP levels of patients included in the study peaked on day 3 of admission (mean 226±114 mg/L). In patients with and without an event, CRP concentrations also peaked on day 3  logistic regression analyses only the 77 first events were included. In the conditional logistic regression analysis we stratified on 10 different event days, with the number of events (cases) decreasing from 27 to 4 with increasing event day and the number of patients in the remaining event-free cohort dropping off from 137 to 7 due to ending of ICU episodes. Meanwhile relatively small numbers of missings arose caused by incidentally missing last CRP changes or last SOFA score changes just before the event-day considered.p = 0.028). A 10% increase in CRP level resulted in a 2.6% increase in the odds for an event . The p-value of the simultaneous effect of CRP change and level on the event odds is 0.059  was estimated with the conditional logistic regression analysis. Effects of additive changes in SOFA score were estimated as SOFA score was not transformed in the analysis. Concerning CRP, effects of multiplicative (relative) changes were studied, as CRP was logarithmically transformed before analysis. From the analysis we found that each additional 10% increase in percent change of CRP resulted in a 3.5% increase in the odds of a first event  and a 7.3 higher event odds . The p-value of the simultaneous effect of SOFA change and level on the event odds was 0.18 . Again after adjusting for SOFA a similar non-significant result was obtained   . It can To determine if a diagnostic and/or therapeutic (re)interventions are indicated in the critically ill surgical patient during the ICU stay, trends in CRP concentrations are often used. In this large prospective study with critically ill general surgical patients we found a significant relation between increase in CRP concentrations and events. However, no significant relation between increase in CRP levels and complications was found.Although many studies showed that increasing CRP concentrations or persistently high CRP levels are suggestive for ongoing inflammation with multi organ failure and poor outcome, these studies mainly included a general ICU population C-reactive protein has been considered as an indicator for adverse postoperative course including both surgical and non-surgical complications as it responds to both infection and inflammation. Mustard et. al. Since it is difficult to diagnose early complications in critically ill patients, other parameters may also be used in the decision making for further diagnostic or therapeutic procedures. These may include the Sequential Organ Failure Assessment Score (SOFA) by means of clinical deterioration. The usefulness of SOFA score in critically ill patient has been validated in large cohorts demonstrating its prediction for mortality and outcome It appears that an increase in CRP levels triggers physicians to perform additional interventions (events). As no relationship between an increase in CRP and postoperative complications is found, we can argue if CRP is a reliable marker. It is important to realize that changes in CRP concentrations should not be interpreted separately from clinical data in clinical decision making. Newer markers are needed and currently being studied as parameters for infection and sepsis and other complications.There are several limitations to our study. The first is that the treating physicians were not blinded for CRP or the SOFA score. We realize that this is a risk for bias. The reason for not blinding the clinician is that we wanted to reflect practice as it is on the ICU. As the clinicians were not blinded for CRP concentrations or SOFA scores, it may have prompted the physicians to order diagnostic tests or perform interventions based on changes in CRP levels or SOFA scores. Yet, this is a reflection of actual practice in the ICU and clinicians should not make decisions based on isolated laboratory values or SOFA scores alone. Another downside of our study is that also non-infectious complications  were included in the analysis. For example patients with postoperative bleeding, ileus or mestenterial ischemia. These patients developed a complication which was not necessary accompanied by an increase in CRP. As this was only a small amount of patients, we can assume that they did not influence our data. Furthermore, as mentioned above our data provided us with more reliable information on the clinical course of the general surgical patients on the ICU. In addition, it might be that in different hospital region or countries, the threshold to perform a diagnostic or therapeutic intervention may differ from our hospital. Nevertheless, the patients included in our study were those admitted into a large level 3 ICU with a broad surgical population and different physicians. We therefore believe that this study is representative for a general critically ill surgical patients admitted into an ICU.In this observational study we conclude that increase in C-reactive protein concentration is a poor parameter for detection of surgical complications in the critically ill surgical patient in the ICU by means of diagnostic procedures or therapeutic (re-)interventions. Yet, we found that when CRP increased, more diagnostic and therapeutic interventions were performed. In addition, we recommend that CRP should not be used by itself for clinical decision making but in adjunct to clinical parameters. Since a combination with the SOFA score does not seem to improve its value, more reliable clinical scoring systems and markers are needed.


The prevalence of food allergy is increasing in westernized countries, affecting around 4% of the population. Although innumerous proteins are encountered in normal diets, only few protein families are commonly implicated as food allergens. In order to be able to predict the allergenicity of food proteins, recent studies focused on intrinsic features of these few families of allergens; however, it is known that extrinsic factors can play a role in allergic processes. The allergenicity of Ber e 1, the major allergen from Brazil nuts, is well established. It has been suggested that natural lipids from Brazil nuts play a role in the development of an immune response towards Ber e 1. Therefore the present study aimed to characterize the humoral response induced by recombinant (r)Ber e 1 in the presence of different classes of lipids, and to investigate the role played by natural lipids in the immune sensitization.. BALB/c mice were sensitised i.p. with rBer e 1 alone or in the presence of different natural lipid fractions. It was found that rBer e 1 alone did not induce antibody production, even in the presence of alum. Only one specific fraction of Brazil nut lipids (SPC C), was able to induce a Th2-type humoral response, with the presence of Ber-specific anaphylactic antibodies, high levels of Ber-specific IgG1, and low levels of Ber-specific IgG2a. In order to test the hypothesis that NKT cells may be involved in the response via CD1 receptor the sensitisation protocol with rBer e 1 and SPC C fraction was tested in mice lacking these cells (JALPHA18 KO mice). These animals presented significantly lower titers of Ber-specific anaphylactic antibodies  than sensitised wild type mice, indicating that one of the pathways by which lipids triggered an immune response involves NKT cells. In vitro assay of TLRs (2 to 9) activation showed that SPC C fraction was not able to activate these receptors. In conclusion, our recent results corroborate the idea that lipids from Brazil nuts are essential for the development of a Th2-type humoral response to rBer e 1 and suggest that the immune response induced by lipids might involve NKT cells.


Treatment standard for patients with rectal cancer depends on the initial staging and includes surgical resection, radiotherapy as well as chemotherapy. For stage II and III tumors, radiochemotherapy should be performed in addition to surgery, preferentially as preoperative radiochemotherapy or as short-course hypofractionated radiation. Advances in surgical approaches, especially the establishment of the total mesorectal excision (TME) in combination with sophisticated radiation and chemotherapy have reduced local recurrence rates to only few percent. However, due to the high incidence of rectal cancer, still a high absolute number of patients present with recurrent rectal carcinomas, and effective treatment is therefore needed.Carbon ions offer physical and biological advantages. Due to their inverted dose profile and the high local dose deposition within the Bragg peak precise dose application and sparing of normal tissue is possible. Moreover, in comparison to photons, carbon ions offer an increase relative biological effectiveness (RBE), which can be calculated between 2 and 5 depending on the cell line as well as the endpoint analyzed.Japanese data on the treatment of patients with recurrent rectal cancer previously not treated with radiation therapy have shown local control rates of carbon ion treatment superior to those of surgery. Therefore, this treatment concept should also be evaluated for recurrences after radiotherapy, when dose application using conventional photons is limited. Moreover, these patients are likely to benefit from the enhanced biological efficacy of carbon ions.In the current Phase I/II-PANDORA-01-Study the recommended dose of carbon ion radiotherapy for recurrent rectal cancer will be determined in the Phase I part, and feasibilty and progression-free survival will be assessed in the Phase II part of the study.Within the Phase I part, increasing doses from 12 × 3 Gy E to 18 × 3 Gy E will be applied.The primary endpoint in the Phase I part is toxicity, the primary endpoint in the Phase II part is progression-free survival.With conventional photon irradiation treatment of recurrent rectal cancer is limited, and the clinical effect is only moderate. With carbon ions, an improved outcome can be expected due to the physical and biological characteristics of the carbon ion beam. However, the optimal dose applicable in this clincial situation as re-irradiation still has to be determined. This, as well as efficacy, is to be evaluated in the present Phase I/II trial.NCT01528683 Treatment of rectal cancer after primary diagnosis depends on initial staging and includes surgical resection, radiation therapy as well as chemotherapy. For T1-2 tumors without positive lymph nodes, surgical resection alone followed by close oncological follow-up is recommended. For node-negative T3 tumors, surgery should be followed by radiochemotherapy followed by adjuvant chemotherapy. In patients with node positive T1-3 tumors, surgical resection should also be followed by radiochemotherapy and adjuvant chemotherapy -10.Advances in surgical techniques such as the establishment of the total mesorectal excision (TME) in combination with advanced radiation and chemotherapy have reduced local failure rates to few percent only ,11,12. HSurgical resection should be evaluated in all instances, and can be a treatment option in this situation for certain patients . HoweverWith advanced photon techniques delivering doses precisely through three-dimensional CT- and MR-based treatment planning, re-irradiation can be performed for recurrent rectal cancer, however, doses are commonly limited to 36 - 45 Gy applied with small safety margins due to the normal tissue exposure during prior radiotherapy. In the past, neutrons had been used for the treatment of recurrent rectal cancer; clinical results with respect to pain control and and local progression-free survival were between 50 and 85% in the different centers ,15.Particle therapy using protons or carbon ions offers distinct physical and biological properties compared to photon radiotherapy. The physical characteristics include a low dose deposition within the entry channel of the particle beam, followed by a steep dose deposition called the Bragg Peak, which is followed by a sharp dose fall-off. Additionally carbon ions offer significant biological advantages through severe radiation damage performed within the irradiated cells which are difficult to repair by the cells' intrinsic repair mechanisms. For various cell lines, RBE values between 2 and 5 have been reported depending on the cell line and endpoint. Therefore, carbon ion radiotherapy is characterised by a higher relative biological effectiveness (RBE) which can translate into improved clinical results.Carbon ion radiotherapy was available by the Department of Radiation Oncology at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt since 1997. Superior treatment results for a number of tumor entities, such as chordomas and chondrosarcomas of the skull base, as well as adenoid cystic carcinomas (ACC) have been shown, and carbon ion radiotherapy is currently performed in the clinical routine for these patients -19. SafeIn Japan, carbon ion treatment has been available for over 15 years, and over 5000 patients with different indications have been treated successfully showing excellent clinical results ,21. For Due to the beneficial dose distributions generated by the particle beam and the higher RBE with carbon ions, the use of carbon ion radiotherapy for recurrent rectal carcinoma is a promising treatment alternative in this patient population. To date, few reports have focussed on re-irradiation using percutaneous photons or intraoperative radiotherapy with electrons in patients with recurrent rectal cancer.In general, recurrent rectal cancers are treatment-resistant tumors, and local high-dose radiation treatment is often limited by organs at risk as well as previously applied radiotherapy after initial diagnosis. Japanese studies using carbon ion radiotherapy for the treatment of recurrences from rectal cancer previously not treated with radiation have shown excellent local control rates which are superior to conventional radiation therapy as well as surgery alone.In a first step, a dose-escalation study had been performed from 67.2 Gy E to 73.6 Gy E in 16 fractions. Local control rates were 93.7% at 5 years at the dose level of 73.6 Gy E with very low rates of treatment related acute or chronic side effects ,21. HoweTherefore, the concept of carbon ion radiotherapy to patients with recurrent rectal cancer with a macroscopic tumor lesion after aggressive primary treatment including radiotherapy is a promising treatment alternative. Due to the physical properties of the particle beam, sparing of normal surrounding tissue supports the use of this concept as re-irradiation in patients with recurrent rectal cancer.Therefore, in the PANDORA-01-Study, this concept will be evaluated; in the first step, the recommended dose will be determined in a dose escalation scheme (Phase I part) prior to the Phase II part of the study.Due to the dose escalation part within this prospective study, the safety of a recommended dose (RD) of carbon ion radiotherapy will be determined using a classical 3 + 3 design. Within the Phase II part, the RD outcome after carbon ion radiotherapy will be evaluated. Results will then be compared to historical controls treated with surgery alone or with conventional radiation techniques or Intraoperative Electron Radiotherapy (IOERT). Patients will be monitored regularly to observe and evaluate treatment outcome and side effects.At the University of Heidelberg, patients with rectal cancer are treated in the interdisciplinary setting consisting of visceral surgeons, medical oncologist and radiation oncologist. Therefore, patients will be provided the best possible oncological care on a professional basis.The purpose of the trial is to determine the MTD for carbon ion radiotherapy for the treatment of recurrent rectal cancer and to determine feasibility of this treatment in patients with recurrent rectal cancer.The primary endpoint is any Grade IV toxicity related to the study treatment according to CTCAE Grade 4.0.The primary endpoint is progression-free survival after re-irradiation at 12 months.The secondary endpoint in the Phase I part is progression-free survival after re-irradiationThe secondary endpoints in the Phase II part are overall survival, toxicity and safety.The trial will be performed as a single-center one-armed Phase I/II study.Patients fulfilling the inclusion criteria will be treated with increasing total doses of carbon ion radiotherapy to evaluate the optimal carbon ion dose with respect to toxicity. The aim of this part is to determine the MTD of carbon ion radiotherapy for re-irradiation of recurrent rectal cancer.Patients will be treated within seven increasing dose regimens starting at 12 × 3 GyE up to 18 × 3 GyE.Patients fulfilling the inclusion criteria will be included into the Phase II part of the study and treated with the MTD determinated in the Phase I part.The primary endpoint is toxicity measured by any Grade IV toxicity related to the study treatment according to CTCAE Grade 4.0. A maximum of 45 patients are projected for the Phase I part of the study. Patients will be followed for at least 3 months after study treatment to document any toxicity according to CTCAE Version 4.0.The primary endpoint is progression-free survival after re-irradiation at 12 months, therefore patients are followed within the trial protocol for a minimum 12 months after completion of study treatment. For the LPI, the final study visit will be 12 months after study treatment to assess the primary endpoint. All other patients will be followed on a regular basis as stated below until death or until 12 months after LPI.After RT, patients are scheduled for follow-up visits every 2 months or as needed clinically including contrast-enhanced MRI or CT, thorough clinical assessment as well as evaluation of blood values including CEA.The last patient included into the study will be followed 12 months after treatment. This is considered the final study visit. All other patients will be followed regularly as described in detail until death or until 12 months after LPI.The overall duration of the trial is expected to be approximately 36 months. Recruitment of the patients is planned over a time period of 24 months, minimum duration of the follow-up phase will be 12 months.Patients with the diagnosis of recurrent rectal cancer will be evaluated and screened for the protocol. All patients fulfilling the inclusion and exclusion criteria will be informed about the study. Patients will be included according to the incidental gender distribution for patients with recurrent rectal cancer, male and female patients will be included.Patients meeting all of the following criteria will be considered for admission to the trial:- Locally recurrent rectal cancer- Inoperable lesion- Macroscopic tumor up to 1000 ml volume- Prior photon irradiation of 20-60 Gy- Time between initial radiotherapy and re-irradiation of at least 12 months- Age ≥ 18 years of age- Karnofsky Performance Score ≥60- For women with childbearing potential, (and men) adequate contraception.- Ability of subject to understand character and individual consequences of the clinical trial- Written informed consent Patients presenting with any of the following criteria will not be included in the trial:- Refusal of the patients to take part in the study- Advanced metastatic disease- Patients who have not yet recovered from acute toxicities of prior therapies.- Known carcinoma < 5 years ago  requiring immediate treatment interfering with study therapy.- Pregnant or lactating women- Participation in another clinical study or observation period of competing trials, respectively.During radiation therapy, the application of steroids or other supportive medication might be necessary due to the nature of the disease. Addtionally, medication required for the individual patient for the underlying illness or for concomitant illnesses  can be applied. Concomitant medication should be discussed with the principal investigator on an individual basis.No concomitant chemotherapy or any other anti-tumor medication is allowed during the treatment period in this trial.For particle therapy, patients will be immobilized using an individual fixation system. For treatment planning, contrast-enhanced CT as well as MR-imaging will be performed for optimal target definition.Patients included to the study will have received 20-60 Gy of photon RT.Organs at risk such as the small intestine, bladder, spinal chord and cauda will be contoured. Dose constraints of normal tissue will be respected according to Emami et al. . The GroA planning target volume (PTV) will be added depending on individual factors such as patient positioning or beam angles chosen and will be between 3 and 10 mm.FDG-PET or SPECT-Examinations may be used in addition to contrast-enhanced MRI for target volume definition but are not mandatory.Carbon ion RT planning is performed using the treatment planning software PT-Planning  including biologic plan optimization. Biologically effective dose distributions will be calculated using the a/ß ratio for rectal cancer as well as for the endpoint late toxicity.No interruptions > 4 days are allowed.Patient positioning prior to particle therapy will be evaluated by comparison of x-rays to the DRRs. Set up deviations > 3 mm are corrected prior to radiotherapy.The intensity-controlled rasterscan system will be used for beam application. Single fractions of 3 Gy E will be applied up to the total dose in the dose escalation cascade.Seven dose levels are planned within the Phase I part:12 × 3 Gy E13 × 3 Gy E14 × 3 Gy E15 × 3 Gy E16 × 3 Gy E17 × 3 Gy E18 × 3 Gy EThe dose will be prescribed to the maximum of the calculated dose distribution for the target volume (PTV). Treatment planning aims in the coverage of the PTV by the 90%-isodose line.Dose specification is based on biologic equivalent dose because of the high relative biologic effectiveness (RBE) of carbon ions, which differs throughout the target volume due to its dependence on various factors. RBE will be calculated at each voxel throughout the target volumes and biological optimization will be performed. The dose prescription used is related to the isoeffective dose GyE  using daily fractions of 2 Gy and a weekly fractionation of 5 × 2 Gy.After the RD has been determined, this dose will be the prescribed dose in the Phase II part of the study.Radiation therapy according to the protocol will be performed in patients included into the study.Patients withdrawn from the trial retain their identification codes. New patients must always be allotted a new identification code.Efficacy of the treatment will be recorded according to the RECIST Criteria.• The main target lesion is defined as the macroscopic tumor delineated for treatment with carbon ion radiotherapy.• A sum of the longest diameter (LD) for the target lesions will be calculated and reported as the baseline sum LD. The baseline sum LD will be used as reference by which to characterize the objective tumor.• All other lesions (or sites of disease) should be identified as non-target lesions and should also be recorded at baseline. Measurements of these lesions are not required, but the presence or absence of each should be noted throughout follow-up.Complete Response (CR): Disappearance of the target lesions• Partial Response (PR): At least a 30% decrease in the sum of the LD of the target lesion, taking as reference the baseline sum LD• Stable Disease (SD): Neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD, taking as reference the smallest sum LD since the treatment started• Progressive Disease (PD): At least a 20% increase in the sum of the LD of the target lesion, taking as reference the smallest sum LD recorded since the treatment started or the appearance of one or more new lesions• Complete Response (CR): Disappearance of all non-target lesions and normalization of tumor marker level• Incomplete Response/Stable Disease (SD): Persistence of one or more non-target lesion(s) or/and maintenance of tumor marker level above the normal limits• Progressive Disease (PD): Appearance of one or more new lesions and/or unequivocal progression of existing non-target lesions• The best overall response is the best response recorded from the start of the treatment until disease progression/recurrence . In general, the patient's best response assignment will depend on the achievement of both measurement and confirmation criteria• Patients with a global deterioration of health status requiring discontinuation of treatment without objective evidence of disease progression at that time should be classified as having "symptomatic deterioration". Every effort should be made to document the objective progression even after discontinuation of treatment.• In some circumstances it may be difficult to distinguish residual disease from normal tissue. When the evaluation of complete response depends on this determination, it is recommended that the residual lesion be investigated (fine needle aspirate/biopsy) to confirm the complete response status.Survival is a secondary endpoint of the study. The duration of survival is the time interval between beginning of carbon ion radiotherapy and the dated of death due to any cause. Patients not reported dead or lost to follow-up will be censored at the date of the last follow-up examination.This study will use the International Common Terminology Criteria for Adverse Events (CTCAE) version 4.0 for toxicity and adverse event reporting. A copy or the CTCAE can be accessed from the CTEP home page.Safety and toxicity of the study treatment will be evaluated by clinical examination as well as imaging studies (MRI or CT).The following parameters will be collected and taken into account in: CEA, age, Karnofsky Performance Score, lesion size.After completion of study treatment, no further treatment is planned and patients wtill be followed up regularly. Follow-up examinations include clinical assessment, contrast-enhanced imaging with MRI or CT, and evaluation of blood values including CEA. Patients will be seen every 2 months after treatment or as needed clinically.Any systemic treatment or chemotherapy is not part of the clinical trial.For tumor progression, treatment alternatives will be evaluated and discussed interdisciplinary considering options of surgical resection, systemic treatment such as chemotherapy, a third course of radiation therapy, or other.This section describes the considerations underlying the choice of the sample size as well as the statistical methodology applied for the analysis of the Phase I and the Phase II part of the PANDORA-01 study. By combining the Phase I and Phase II part within a single study, the results of those 9 patients that received the MTD within the Phase I part can be used for the assessment of the efficacy in the Phase II part. Therefore, the required sample size of the Phase II part can be reduced, which is highly desirable from an ethical point of view. More details on the evaluation can be found in the statistical analysis plans prepared for the two study parts which will be finalized prior to performing any analyses and which have to be authorized by the study biostatistician and the principal investigator.It is the aim of the Phase I part of this study to determine the MTD for carbon ion radiotherapy for the treatment of recurrent rectal cancer. The primary endpoint is the occurrence of a dose limiting toxicity defined as any Grade IV toxicity according to CTCAE Version 4.0, possibly, probably or definitely associated to study treatment and occurring during 30 days after completion of the study treatment.The calculation of the sample size for the Phase I part of the PANDORA-01 trial is based on the traditional 3 + 3 dose escalation scheme which is conducted as follows:Patients are treated in cohorts of three each receiving the same dose. For the assessment of a dose limiting toxicity (see definition above) patients are observed for 30 days after application of the study treatment.If none of the three patients of a cohort exhibits a dose limiting toxicity, the next cohort of three patients receives the next higher dose.Otherwise, if at least one patient of a cohort exhibits a dose limiting toxicity, a further cohort of three patients is treated at the same dose level without escalating the dose.If exactly one out of the six patients treated at this dose exhibits a dose limiting toxicity, the trial continues as planned at the next higher dose level.If two or more patients out of the six patients treated at this dose exhibit a dose limiting toxicity, the dose escalation stops at that level and the next lower dose is considered as the MTD. When the escalation has stopped, additional patients will be treated at the MTD to a total of nine patients.The Phase I part of the trial is conducted to determine the MTD of carbon ion radiotherapy by consideration of a total of seven dose levels. Therefore, the maximum sample size is 45 patients (six dose levels with a maximum of 6 patients each and 9 patients at the MTD).Primary endpoint to determine the MTD that is chosen out of seven dose levels is any Grade IV toxicity according to CTCAE Version 4.0, possibly, probably or definitely associated to study treatment and occurring during 30 days after completion of the study treatment. Secondary endpoints are other safety data on the applied dose levels as well as response, progression-free survival, and overall survival.π for patients with recurrent rectal cancer receiving carbon ion radiotherapy. According to results reported in the literature, the 12 month progression-free survival rate for patients treated with conventional radiotherapy is estimated to be 0.60. Thus, the confirmatory analysis of the primary endpoint assesses the following test problem: H0: π ≤ 0.60 = π0 versus H1: π > 0.60.The primary objective of the Phase II part of PANDORA-01 is to evaluate the 12 month progression-free survival rate α = 0.05. A power of 1-β = 0.80 is aspired for the alternative of a 12 month progression-free survival rate of π1 = 0.80, i.e., for an absolute improvement of 0.20 as compared to conventional radiotherapy. As this Phase II part of PANDORA-01 is the first study providing data on the efficiency of carbon ion therapy for the treatment of recurrent rectal cancer, there is considerable uncertainty with respect to the actual 12 month progression-free survival rate resulting from carbon ion therapy in this patient population: The rate may be higher than 0.80 thus requiring fewer patients for the study; or it may be slightly lower than 0.80 while the improvement may still be clinically relevant, but with the consequence for the study that more patients than initially planned would be required to assure the desired power. For this reason, an adaptive version of Simon's optimal two-stage design is used for this Phase II study part [n1 = 14 patients and further n1 = 25 patients recruited for the second stage if the study is continued after stage 1. Using the decision rules given, this design assures the desired power 1- β = 0.80 for the alternative π1 = 0.80 and has an expected sample size of 20.8 under the null hypothesis π0 = 0.60. According to the design of the Phase I part of PANDORA-01, 9 patients are already treated there with the MTD.The sample size calculation for the confirmatory analysis of the Phase II part of the study refers to the test problem given above that will be assessed applying a one-sided binomial test at an overall type I error rate of udy part ,24. ThisThe primary outcome variable is the 12 month progression-free survival rate. Secondary objectives are the assessment of the 12 month overall survival rate as well as safety and tolerability.More details on the statistical analysis will be provided in the statistical analysis plan which is finalized prior to performing any analysis and which has to be authorized by the study biostatistician and the principal investigator.An independent Data and Safety Monitoring Board (DSMB) will monitor the recruitment, the reported adverse events and the data quality at least twice a year. Based on its review the DSMB will provide the Principal Investigator (PI) with recommendations regarding trial modification, continuation or termination.According to the §13 of the German GCP-Regulation all important trial documents will be archived for at least 10 years after the end of the PANDORA-01 trial. According to the §28c of the German X-Ray Regulation (RöV) and the §87 of the German Radiation Protection Regulation (StrlSchV) the informed consent forms including patients' consent for trial participation, application of irradiation and data transmission to the competent authority will be archived for at least 30 years after the end of the trial. The Study Center at the Deparment of Radiation Oncology Define will be responsible for archiving allrelevant data.The protocol will be condected according the guidelindes of Good Clinical Practice (GCP) and the ethical principles described in the Declaration of Helsinki .The trial will be carried out by adhereing to local legal and regulatory requirements.The study plan has obtained approval by the Institutional Review Board (IRB)/Independent Ethics Committee (EC) of the Medical Faculty Heidelberg. Before start of recruitment a positive vote of the Bundesamt für Strahlenschutz (BfS) is necessary.The aim of the present PANDORA-01 trial is to evaluate the MTD for carbon ion radiotherapy in patients with recurrent rectal cancer, previously treated with radiation; subsequently, the efficacy of carbon ion radiotherapy will be evaluated in the Phase II part of the study.To date, the possibility to treat patients with inoperable recurrent rectal cancer with radiation as a second course of radiotherapy had proven only modest effectivity, with a potential risk of treatment-related side effects ,15,25,26Taking all these aspects into consideration, the present trial was designed as a Phase I/II trial firstly evaluating the MTD for carbon ion radiotherapy, followed by evaluation of efficacy in the Phase II part of the trial.Carbon ion radiotherapy will be applied using the rasterscanning technique. A typical treatment plan can be observed in Figure In conclusion, the PANDORA-01 study is the first trial to evaluation high-LET particle therapy with carbon ions as re-irradiation in patients with locally recurrent and unresectable rectal cancer.ACC: Adenoid Cystic Carcinomas; BDSG: Bundesdatenschutzgesetz; CEA: Carcino-Embryonal Antigen; CHT: Chemotherapy; CRF: Case Report Form; CRP: C Reactive Protein; CT: Computer tomography; CTCAE: Common Toxicity Criteria for Adverse Events; CTV: Clinical target volume; DKFZ: Deutsches Krebsforschungszentrum; DRR: Digitally reconstructed radiograph; DVH: Dose volume histogram; GCP: Good Clinical Practice; GSI: Gesellschaft für Schwerionenforschung; GTV: Gross tumor volume; Gy: Gray; Gy E: Cobalt Gray equivalent; ICD: International Classification of Disease; LET: Linear energy transfer; LLUMC: Loma Linda University Medical Center; MGH: Massachusetts General Hospital; MR: Minor responses; MRI: Magnet resonance imaging; MTD: Maximal Tolerable Dose; n.a.: Not applicable; NIRS: National Institute of Radiological Sciences; OS: Overall survival; PR: Partial response; PTV: Planning target volume; RBE: Relative biological effectiveness; SD: Stable disease; RT: Radiation therapy; SAE: Severe Adverse Events; TME: Total Mesorectal Excision.The authors declare that they have no competing interests.SEC, MK, RP, REC, MD, PF and JD have developed the study concept. SEC, JD, MK wrote the study protocol and obtained ethics approval. SEC, DH, JD, JW, MWB and DJ will provide patient care. OJ will perform treatment planning and beam application for carbon ion radiotherapy. SEC, DH, JD, and MK will implement the protocol and oversee collection of the data. All authors contributed to and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2407/12/137/prepub


Chronic kidney disease is common and patients with many co-morbid conditions frequently have to undergo surgical procedures and, therefore, require effective pain management. The pharmacokinetics of various analgesic agents are not well studied in patients with chronic kidney disease and the risk of accumulation of the main drug or their metabolites, resulting in serious adverse events, is a common scenario on medical and surgical wards. It is common for these patients to be cared for by 'non-nephrologists' who often prescribe the standard dose of the commonly used analgesics, without taking into consideration the patient's kidney function. It is important to recognize the problems and complications associated with the use of standard doses of analgesics, and highlight the importance of adjusting analgesic dosage based on kidney function to avoid complications while still providing adequate pain relief. Illustrative clinical scenario:- an example to illustrate the problem.2 of 60, pO2 of 86 and oxygen saturation of 95%. His mental state improved transiently with intravenous naloxone, confirming opioid effect. How could this situation have been prevented while effectively providing pain relief?A 63-year-old man with diabetes and end stage renal disease on maintenance continuous ambulatory peritoneal dialysis was admitted to the hospital with gangrene of the left foot and underwent left below-knee amputation under spinal anesthesia. Postoperatively, he was given meperidine (Demerol) 50–75 mg intramuscularly every 3 hr, as required, by the orthopedic surgeon, but this was found to be ineffective in controlling pain. The anesthetist ordered morphine 10–15 mg intramuscularly or subcutaneously every 3 hr as required (pro re nata) in the evening. He received 325 mg of meperidine in the first 24 hr and additional 200 mg of meperidine next day  and 55 mg of morphine within the first 48 hr after surgery. 48 hr after surgery, he was found to be confused and somnolent. On examination the patient was drowsy and somnolent, but arousable with twitching of arms, and complained of mild pain at the stump site when awakened. He had labored breathing with a respiratory rate of 8 breaths per minute. An arterial blood gas showed pH of 7.19, pCO1 and is regularly accompanied with various co-morbidities. Often these patients with various co-morbidities undergo operative procedures and require analgesics. The most-responsible physician providing the care to these individuals during their hospitalization is often a non-nephrologist. Opioids are commonly used in the management of post-operative pain, and often a standard dose is used by the health-care providers without taking into consideration kidney function2. In North America, morphine and meperidine (Demerol) still remain the commonly used parenteral agents, and acetaminophen with codeine (Tylenol #3) a commonly used oral agent for management of post-operative pain in patients with3 and without renal failure. Prolonged central nervous system and ventilatory depression due to morphine and other opioids have been known for over a century in patients with kidney failure10 and the various contributing factors are outlined in11, but also in patients without kidney disease13. It is important to highlight the issue of central nervous system (CNS) and respiratory depression with opioid analgesics in patients with CKD and formulate strategies to prevent these complications, while providing effective pain relief.Chronic kidney disease (CKD) is common14 i.e., ischemic pain from peripheral vascular disease, neuropathic pain of polyneuropathy (diabetes), bone pain from osteoporosis or dialysis-associated amyloidosis, and musculoskeletal pain that may or may not be related to kidney disease. Post-operative pain is often nociceptive, whereas chronic pain may be nociceptive, neuropathic or mixed. It is also important to recognize that depression is common in CKD15 and that it may complicate the management and patient’s ability to cope with pain16.In addition to the post-operative pain, patients with CKD may have underlying chronic pain that is often multi-factorial17.Assessment of pain requires detailed history to elucidate the cause of pain, its location, nature , intensity and its impact on physical, social and emotional functioning18. Acute pain results from direct stimulation of sensory neurons, called nociceptors. Nociceptors have two types of axons, the rapidly conducting thinly myelinated Aδ fibers that mediate the initial phase of acute pain that is extremely sharp pain, and the more slowly conducting unmyelinated C fibers mediate the second phase of acute pain that is more prolonged and less intense following injury. Nociceptors can be stimulated by mechanical, thermal, chemical and inflammatory stimuli18.Acute pain is a protective and an adaptive response to injury, whereas chronic pain or the persistence of pain beyond the healing phase is a maladaptivePain lasting longer than 3 months or beyond the duration required for complete tissue healing is called chronic pain. It may be nociceptive, resulting from prolonged tissue injury with persistent activation of nociceptors, neuropathic resulting from a lesion or a process affecting the somatosensory system or mixed processes.19.Pain intensity may be measured by one of the major pain rating scales including verbal, numerical and visual analogue scales. However, a numerical rating scale comprising of a range of numbers from 0 to 10, is the most widely used system in clinical practice and is generally based on a subjective 10-point scoring system, where 0 denotes the absence of pain and 10 the worst pain imaginable17. In addition, assessment of concomitant medications and co-morbidities is important when selecting analgesic agent(s). Adjuvant analgesics and non-pharmacological methods of pain control are important to consider in such circumstances17. We review the strategies to manage acute pain in CKD with main focus on the use of opioids since most of the challenges occur in the use of opioids in CKD.Effective pain management requires a multifaceted approach with an understanding of the type , underlying cause, assessment of intensity and duration of pain20  step-wise approach was proposed for pain management in patients with CKD20  and thisgesics’ .Box 1. Opiate: Naturally occurring alkaloid i.e., morphine or codeine.Opioid: Any natural or synthetic compound that has morphine-like properties.Balanced analgesia: Principle of combining different classes of analgesics to optimize efficacy while minimizing side-effects.Co-analgesic: A drug administered alongside opioids enabling a reduction in opioid dose.Adjuvant: A substance that helps and enhances the pharmacologic effects of an agent .Acetaminophen: Has potent analgesic and antipyretic properties and is effective in various acute and chronic painful syndromes. It is the analgesic of choice in the elderly and in patients with kidney disease22 and should be considered in all patients (except in patients with hepatic insufficiency) experiencing pain, regardless of pain level, until pain is relieved or up to a maximum dose of 3,000 mg a day23 or 2.6 g/d in high-risk patients24 . It often does not require dose adjustment in CKD but some authors recommend increasing dosing interval from every six to eight hours when GFR is <10 mL per minute25. Acetaminophen is underutilized in the peri-operative period and when prescribed it is often in an "on demand" basis rather than "by the clock"17. We suggest consider prescribing at least half of total daily dose “by the clock” (opinion MSP) e.g., Acetaminophen 500 mg four times a day and remaining dose could be given “on demand” or in combination with other agents.Anti-inflammatory agents: Nonsteroidal anti-inflammatory drugs (NSAIDs) or cyclo-oxygenase (COX-2) inhibitors block prostaglandin synthesis and, when used as co-analgesic, reduce opioid need by 30–50%. However, because of their gastro-intestinal and cardio-renal side effects, they should be avoided for prolonged use in CKD, as these agents may decrease renal blood flow and may precipitate acute renal failure and can cause life-threatening hyperkalemia. However, if used, it should be for short term management (3 to 7 days) of acute pain and consider short-acting agents26 with careful monitoring of renal function and serum potassium.Adjuvant analgesics are medications with a primary indication other than pain that may possess analgesic activity or modify pain response. These are often helpful for management of chronic neuropathic pain. Examples include cabamezapine, gabapentin, and pregabalin. These agents are not required for management of acute pain. However, CKD patients may have associated underlying chronic neuropathic pain that could affect acute pain response or management. Therefore, some patients may already be taking these agents for control of their 'chronic pain’ and these agents may be stopped inadvertently in the peri-operative period. If this is the case, adjuvant analgesics should be resumed when possible, with considerations being taken for the possible drug-drug interactions when prescribing opioid analgesics for acute pain. It is important to understand that the dose of these agents (adjuvants) may also need to be reduced because of renal dysfunction.28. In addition to CNS and respiratory depression, constipation is a common side effect that is important to identify and manage, especially in patients on peritoneal dialysis, as constipation is the common cause of catheter malfunction29, and appropriate laxatives should be used in conjunction with treatment.The relative potency of commonly used opioids is shown inMorphine: Morphine is the most studied opiate in kidney disease. It is primarily an agonist at the µ-receptors with pain relief at µ1-receptors, and causes respiratory depression and constipation through its agonist action at µ2-receptors14. Morphine is metabolized in the liver to several metabolites30. Of these diamorphine and morphine-3-glucuronide (M3G) do not bind to opiate receptors, whereas normorphine and morphine-6-glucuronide (M6G) do, with M6G being approximately 10-fold more potent than morphine31. All metabolites are excreted in the urine along with about 10% of the parent compound. M6G accumulates in kidney failure and causes CNS and respiratory depression32. M6G crosses the blood brain barrier (BBB) slowly, and once it crosses the BBB, the CNS effects may be prolonged and may persist after stopping morphine or after hemodialysis, as the M6G slowly re-equilibrates across the BBB back into systemic circulation6. Transport of M6G across the BBB is an active process mediated by 170-kd P-glycoprotein. P-glycoprotein is an ATP-dependent carrier system that acts as an efflux pump to transport chemicals or metabolites from endothelial cells to vascular compartment and inhibition of this results in an increase of M6G in the brain34. The analgesic and respiratory depressant effects are related to serum concentrations of both morphine and M6G31. A dosage reduction of 25%, 50% and 75% is recommended in patients with mild (stage 3), moderate (stage 4) and severe kidney failure (stage 5) respectively. However, 20–25% of patients may tolerate the full dose of morphine without ill-effects because ofA118G polymorphism36.Meperidine: Normeperidine, an active metabolite of meperidine, is neurotoxic and accumulates in renal failure and may cause a range of neuroexcitatory effects ranging from irritability to agitation to seizures37. Although normeperidine is removed by hemodialysis38, its regular administration iscontraindicated in patients with any degree of renal failure39.(Dextro)Propoxyphene: It is no longer available in North America and its metabolite norpropoxyphene is excreted by the kidneys and accumulates in renal failure39. This results in CNS and respiratory depression, cardiac conduction disturbances and hypoglycemia. Both the parent drug and its metabolite are not removed by hemodialysis and iscontraindicated in patients with renal failure39.Hydromorphone: Hydromorphone is an analogue of morphine with shorter duration of action and with excellent efficacy in moderate to severe pain. It is five to seven times potent than morphine. It is eliminated by both hepatic (60%) and renal routes40. Hydromorphone doesn’t accumulate in renal failure because of its rapid conversion to its less-potent metabolite hydromorphone-3-glucuronide (H3G) that accumulates in renal failure but is effectively removed by hemodialysis41. However, typical opioid adverse effects have been reported in patients with renal failure42, but experience suggests efficacy without excess toxicity, if monitored carefully43.Codeine/Dihydrocodeine: Codeine is metabolized by the liver to a variety of active metabolites  that are renally excreted44. The half-life of codeine is prolonged 5-fold in hemodialysis patients45. Codeine and its metabolites accumulate in renal failure and can cause hypotension and CNS and respiratory depression47. A similar elimination pathway is proposed for elimination of dihydrocodeine, although this has not been fully evaluated39. Dihydrocodeine can cause prolonged narcosis after therapeutic doses in patients with acute48 or chronic renal failure49. Therefore, these agents should be used with caution in patients with renal failure. A reduction in dose by 50% is suggested for codeine in renal failure45 and chronic use should be avoided.Oxycodone: Oxycodone is a strong opioid with a higher oral bioavailability. It is metabolized by the liver to active metabolites – noroxycodone and oxymorphone50. Approximately 19% of the drug is excreted unchanged in the urine. The clearance of oxycodone and its metabolites is reduced in renal failure50 and results in an increase in plasma concentration by 50% and prolongation of its half-life by an hour50. There is lack of consensus of its use in CKD because of varied case reports of toxicity and good tolerance. When required, use cautiously and start with a lower dose51.Buprenorphine: Buprenorphine is a long-acting semi-synthetic partial agonist with the advantage of having less respiratory depression and hypotension53 but has a ceiling effect55. There is no significant difference in the clearance of the drug in patients with normal or impaired renal function. It has limited oral bioavailability because of an extensive first-pass metabolism. Sublingual, transdermal or parenteral administration is required. It is extensively metabolized by the liver with less than 30% renal excretion. The metabolite norbuprenorphine may accumulate in renal failure that has minor analgesic activity. Buprenorphine is 96% protein bound so is not dialyzable56.Fentanyl, Alfentanil, and Sufentanil: Fentanyl, Alfentanil and Sufentanil are potent opioid receptor agonists, with a rapid onset of action and shorter duration of action. Fentanyl is rapidly metabolized in liver to inactive metabolites. Less than 10% of the parent drug is excreted in urine with no significant accumulation in CKD, but there is considerable inter-patient variability in fentanyl pharmacokinetics when given as a continuous infusion or via transdermal route. However, no dosage modification is necessary in patients with renal failure when fentanyl is given as a bolus. However, prolonged sedation is observed in critically ill patients when fentanyl is given as a continuous infusion, as its half-life increases to 25 hr39 due to saturation of its distribution sites, independent of renal function. Accumulation of fentanyl may occur when given by infusion39 or transdermal patch. Its clearance may be altered in advanced kidney disease57 and prolonged sedation and ventilatory depression have been observed in patients with end stage renal disease following fentanyl infusion39. Fentanyl is highly protein bound (80–86%), has a high volume of distribution, and removal by hemodialysis is negligible59. Opioid-naïve patients should not be initiated on transdermal fentanyl because of its variable absorption.Tramadol: Tramadol is an opioid analgesic that also inhibits serotonin and noradrenaline reuptake. It is extensively metabolized by the liver and 30% of the parent drug and 60% of active metabolites are excreted in the urine60. It is effective for both nociceptive and neuropathic pain and has the advantage of less sedation and respiratory depression compared to other opiates. A common side effect is nausea. A rare but important side effect is seizures, especially in patients taking medications that lower the seizure threshold, like selective serotonin reuptake inhibitors (SSRI). In addition, tramadol may precipitate serotonin syndrome61  in patients taking SSRI62. In advanced CKD, the elimination half-life of tramadol may double60 and the dose should be decreased to 100 mg every 12 hr in patients with eGFR of 30 ml/min and 50 mg every 12 hr when eGFR is <10 ml/min. Tramadol is significantly removed by dialysis and should be administered after hemodialysis on dialysis days63.Methadone: Methadone is a synthetic opioid with five to 10 times the potency of morphine, is highly protein bound (70–87%) and has a half-life of 30 hr. Approximately 20% after a single dose is excreted unchanged and about 30% as inactive metabolites in the urine39. There is a 3-fold increase in the excretion of metabolites on chronic dosing, suggesting enhanced metabolism64. The removal by hemodialysis is insignificant65. Although in 2 patients with CKD the plasma concentrations were no higher than patients with normal renal function66, there is a well-described risk of accumulation and toxicity with methadone, even in patients with normal renal function, so experienced specialist supervision is warranted. A dose reduction of 50% to 75% is suggested in patients with renal failure, but it is difficult to use in patients with CKD because of its long half-life and wide inter-individual variation in clearance65. In some countries, methadone may require a specialist in pain management with a special license to prescribe it, and that may limit its use in acute pain management. However, methadone should not be used in opioid naïve patients.67 in patients with CKD with68 and without dialysis43. The general principles of pain assessment and management should be adopted and analgesia should be prescribed incorporating the modified WHO analgesic ladder20 in patients with CKD, with close and frequent monitoring for side effects of drug or its metabolite accumulation. The nephrologist and a pharmacist should be involved in the management of these patients. The non-opioid analgesics should be used early and ‘by the clock’, rather than ‘on-demand’, and the need for opioid analgesics should be re-evaluated every 24–48 hr, as most patients may tolerate the prescribed initial dose of the opioid analgesics, with toxic effects often emerging after 48 hr, when the parent drug and its metabolites starts accumulating. Vigilance in nursing is also required to monitor for early effects of opiate toxicity.Patients with CKD have a high burden of co-morbidities that modulate pain response, and when these individuals undergo operative procedures, standard orders for pain control can be written without taking into consideration the patient's kidney function. Unfortunately, the data on the effects and tolerability of various analgesic agents are limited in such individuals and, given the lack of data, the recommendations are mainly based on expert opinionBox 2. Before prescribing analgesics, consider kidney function to avoid toxicity that may occur from accumulation of the parent drug or their metabolites.The general principles of pain assessment and management should be adopted and analgesia should be prescribed incorporating the modified WHO analgesic ladder.Co-analgesics like acetaminophen should be considered “by the clock” rather than “by demand”.Do not write standing (or long-term) orders for opioids. Reassess the need and the dose of opioids every 24–48 hr.Avoid fentanyl transdermal patch in opioid-naïve patients. I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. The manuscript is improved. However, the authors have not responded to my comment regarding adjuvant medications . The authors have still not provided a statement 'that a dose reduction may be required for patients with renal insufficiency' within the revised article. The authors only refer to drug-drug interactions and do not mention that adjuvant medications require dose adjustments with a clinical disease such as renal insufficiency. This problem is independent from any drug-drug interaction. It is important that this point is addressed by the authors in order to improve this articleI have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. The first clinical scenario includes meperidine as a drug used in the patient. The use of meperidine has significantly been reduced in the USA and is monitored as a negative finding when used in patients over 60. Thus hospitals have made efforts to reduce or eliminate its use except in treatment of rigors and given in low doses only. I am not sure if this would be the best scenario to start the article, although its issues with renal insufficiency are substantial.I would refrain from the use of the word 'narcotic' in your discussion in favor of the word opioid.In the discussion regarding 'adjuvant medications' there is no mention that nearly all these medications require dose adjustments in renal insufficiency. Since the article focuses on this topic, I believe it should be included beyond just mentioning that some patients may be using these medications.The last sentence in the 'Acetaminophen' section gives specific dosing recommendations to give half of the daily dose followed by round the clock dosing.  Is this opinion or should a reference be included?Since propoxyphene is no longer available, I would consider eliminating it from the discussion.  I am unsure if it is still being used in other countries.  If so, I guess I would leave it in.The Codeine/Dihydrocodeine paragraph makes no mention of the active metabolite morphine from codeine. Discussion of other drugs in this section refer to actual names of metabolites. Given that morphine was discussed earlier in the document, including this information is important in my view.The chart indicating % amounts in the column headed by eGFR/ml rates does not really say that the percentages indicate a percent dose reduction.  It should be made more clear even though obvious to me.  The methadone section says that it requires a special license to prescribe. This is not entirely true. The special license is only required when treating opioid addiction. If methadone is used for pain control, no special license is needed. I would also include that methadone is not to be used in opioid naïve patients as you do with the fentanyl patch.I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. I approve this article. However, on table 3 and figure 1, oxycodone with acetaminophen is considered step 2 of  the WHO analgesic ladder but oxycodone by itself is considered step 3. I would change this.I have read this submission. I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.


Oncorhynchus mykiss) larvae. This was conducted by allowing larvae with the same emergence time, but with different yolk sizes, to interact in pairs for 24 h. The results show that individuals with larger yolks performed more aggressive acts, resulting in a suppression of aggression in individuals with smaller yolks. A higher brain serotonergic activity confirmed subordination in larvae with small yolks. The relationship between social dominance and yolk size was present in siblings, demonstrating a link between interfamily variation in energy reserves and aggression, and suggests that larger yolk reserves fuel a more aggressive personality during the initial territorial establishment in salmonid fishes. Furthermore, socially naïve larvae with big yolks had lower serotonin levels, suggesting that other factors than the social environment causes variation in serotonergic transmission, underlying individual variation in aggressive behavior.There is a surging interest in the evolution, ecology and physiology of personality differences. However, most of the studies in this research area have been performed in adult animals. Trait variations expressed early in development and how they are related to the ontogeny of an animal’s personality are far less studied. Genetic differences as well as environmental factors causing functional variability of the central serotonergic system have been related to personality differences in vertebrates, including humans. Such gene-environment interplay suggests that the central serotonergic system plays an important role in the ontogeny of personality traits. In salmonid fishes, the timing of emergence from spawning nests is related to energy reserves, aggression, and social dominance. However, it is currently unknown how the size of the yolk reserve is reflected on aggression and dominance, or if these traits are linked to differences in serotonergic transmission in newly emerged larvae. In this study we investigated the relationship between yolk reserves, social dominance, and serotonergic transmission in newly emerged rainbow trout ( Over recent decades, there has been a rising scientific interest in the causes and consequences of individual variation in behavior and physiological traits. This is reflected in the substantial number of reviews published on this topic In many animal groups mortality is most pronounced early in ontogeny, implying that selection would have the greatest impact on personality during this time of development Behavioral traits affected by early experiences may be reflected in long lasting alterations in brain function. For example, social isolation in the time window between post-weaning and adolescence has been demonstrated to have a persistent effect on behavior, brain architecture and neurotransmission in rats In salmonid fishes, the timing of emergence is a crucial niche shift where larvae emerge from the spawning nest in search of exogenous feed and to establish a territory Thus, the aims of the present study were to investigate whether the propensity to become dominant co-varied with the amount of energy reserves (yolk reserves), and how these factors are reflected in 5-HT signaling in socially inexperienced rainbow trout larvae. This was conducted by collecting newly emerged larvae, from artificial spawning nests, and letting similar sized larvae with different yolk volumes interact in pairs. Brains were collected after 24 hours and analyzed for 5-HT and its catabolite 5-HIAA in isolated and interacting fish with big and small yolks. The ratio between 5-HT and 5-HIAA were used as an index of 5-HT activity.All animal procedures used in this study followed the policy and ethics as described by FELASA, Federation of European Laboratory Animal Science Associations. The Technical University of Denmark Aquaculture division holds, according to the national legislation of Denmark, the rights for fish husbandry, including tagging and humane sacrifice. DTU Aqua was given this authorization through the Ministry of Food, Agriculture and Fisheries, Danish veterinary and Food administration, Section for Aquaculture. The experiments in the present paper were conducted according to this national legislation, and the institutional guidelines at DTU Aqua. More specifically, marking of animals did not exceed the authority given to DTU Aqua nor did it exceed the Danish legislation on animal protection §10, where marking has been performed while animals were anesthetized, and no lasting suffering or limitations was inflicted to the animal. Termination of all experimental animals were conducted according to the legislation on animal protection § 12. All animals were terminated using MS 222 and no pain was inflicted.The larvae used in the present study originated from commercial rainbow trout. Eggs were reared in incubator trays with a temperature varying between 7 and 10°C, at the Technical University of Denmark, DTU aqua, the North Sea Research Park, Hirtshals, Denmark. Larvae were transferred from the incubator trays to three artificial spawning nests after hatching. In short, these artificial spawning nests consisted of three parts; a flat holding tray with golf balls as bottom substrate, an emergence tunnel, and a sampling net, as described by Vaz-Serrano et al. 3) of the yolk and the larval body. The remaining yolk was then determined using the following equation:Larvae sampled from the collecting nets were immediately separated and isolated in 30 ml falcon tubes, thereafter photographs were taken and used for calculations of body and yolk size as described in Andersson et al. (2011). In short, 2-D digital images of larvae were processed using image J . The yolk was considered as a prolate spheroid, and the volume of the larval body was determined by calculating the volume of the head (sphere) and the larval body (cylinder). Remaining yolk size was determined by calculating the volume  or small yolks (0–5%), were kept for further experimentation. These groups of larvae were collected during the first 4 days of emergence from the artificial nests. After this time the yolk amount was less than 10%. An analysis of covariance (ANCOVA) was conducted to investigate if the experimental groups differed in yolk size independently of body volume, and the results demonstrated a significant difference in yolk sac size between small and big in all experimental groups .After being classified as having big or small yolks larvae were marked with different colored visible implant elastomes  according to a modified method described by Jensen et al. 3 in experimental round 1 and 221±22 mm3 in round 2.This study consisted of two experimental rounds. In the first round, eggs and larvae from three full-sib families were used. The families were kept separated throughout the experimental round. Following emergence 5 pairs from each family were collected and allowed to interact. These pairs consisted of larvae with different yolk size (see above) but similar larval body sizes . Furthermore there were there no significant differences between total body volume between the interacting fish . The second round of experiments was conducted to ensure that the behavioral data, from round one, were not biased by a higher total volume in the group with bigger yolks. In this round eggs and larvae originated from a mixed batch of eggs . In this round eight pairs with similar total size  but different yolk sizes (see above) were allowed to interact. Larvae had a total volume of 185±45 mmIn experimental rounds 1 and 2 each pair were video filmed for the two first hours after being inserted in the observation chambers. After filming, the larvae were kept in the observation chambers until the next day.The video recordings of each larval pair were analyzed to determine the social status of the larvae. Social dominance was determined by counting aggressive attacks, and dominance was considered to be established when one of the aggressive individuals became unidirectional while the other combatant only performed avoidance behavior. The aggressive acts studied in the present paper were biting, pushing and charging. Socially inexperienced larvae, consisting of 16 larvae, 8 with large yolks and 8 with small yolks, were kept isolated in the observation aquariums. These larvae originated from the same families as used in experimental round 1. Three larvae with large yolks and three larvae with small yolks originated from two of the three families, and two larvae with large yolks and two larvae with small yolks originated from the third family. Socially isolated larvae and larvae from experimental round 1 were terminated with an overdose of MS 222 after being held in the observations aquarium for 24 h. The larval brains were then rapidly dissected under a stereo microscope, frozen in liquid nitrogen and stored at −80°C for analysis of brain monamines and their metabolites.−1 sodium phosphate, 1.4 mmol l−1 sodium octyl sulphate and 12.26 µmol l−1 EDTA in deionized (resistance 18.2 MW) water containing 7% acetonitril brought to pH 3.1 with phosphoric acid. Samples were quantified by comparison with standard solutions of known concentrations and corrected for recovery of the internal standard using HPLC software .The larval brains were weighed, after which they were homogenized in Sodium acetate buffer , 16 pellets NaOH and internal standard ) using an ultrasonic disintegrator. Thereafter they were centrifuged at 17,000 rpm for 5 min. The supernatant was removed and analyzed by high-performance liquid chromatography (HPLC). The monamines 5-HT, 5- Dopamine (DA), and Noradrenalin and the metabolite of 5-HT and Hydroxyindoleacetic acid (5-HIAA) were quantified using HPLC with electrochemical detection. The HPLC system consisted of a solvent-delivery system , an autoinjector , a reverse phase column  and an ESA Coulochem II detector  with two electrodes at −40 mV and +320 mV. A conditioning electrode with a potential of +40 mV was employed before the analytical electrodes to oxidize any contaminants. The mobile phase consisted of 86.25 mmol lIn the current study we used the ratio of the catabolite to its parent monoamine as an estimation of central monoaminergic activity; 5-HT-ergic activity [5-HIAA]/[5-HT]. Because of interacting peaks, concentrations of the NE metabolite 3-Methoxy-4-hydroxyphenylglycol (MHPG), the DA metabolite 3,4-Dihydroxyphenylacetic acid (DOPAC), and NE-ergic and DA-ergic activity could not be detected.All data are presented as mean ± SE, if not otherwise stated. A Pearson chi-square test was applied to determine if the frequency of individuals having big or small yolks differed between groups of larvae turning dominant or subordinate. Data on brain monoamines, their metabolites and monaminergic activity were not normally distributed, and differences between socially inexperienced larvae with big and small yolks, and socially dominant and subordinate larvae, were investigated using Mann-Whitney U-tests. Statistical analyses were conducted using Statistica .On average larvae performed the first aggressive act 31±8.9 min after being inserted in the observation chambers. The average fighting time before the aggression turned unidirectional was 9.0±1.2 min. During this time the dominant and subordinate larvae performed respectively, 5.2±1.0 and 2.5±1.0 aggressive acts. After establishment of the dominant/subordinate relationship, the dominant individuals performed 2.3±0.37 aggressive acts, while the subordinate fish did not perform any aggression during the remaining time of the 2 h observation time.In round 1 of the experiments, where larvae with different sized yolks but no difference in larval body size were allowed to interact, 14 out of 15 individuals turning dominant had big yolks  . AnalogoSocially subordinate individuals had significantly higher brain [5-HIAA]/[5-HT] ratios   and tendIn socially inexperienced larvae that were kept isolated 24 h after emergence, brain concentrations of 5-HT were significantly lower in individuals with big yolks compared to individuals with small yolks  . This waThe current study demonstrates a propensity to become socially dominant in larvae that emerge from the spawning nest with large yolks. This was demonstrated by allowing larvae, with the same emergence time, to interact in pairs.Previous studies of rainbow trout lines, selected for high and low post-stress plasma cortisol, demonstrate that these lines differ in boldness and in the propensity for social dominance (Reviewed by Øverli et al. In the current study, the relationship between yolk size and social status was present between offspring originating from the same family, demonstrating that this co-variation of aggression and energy reserves is present within sibling groups. This is consistent with other studies, demonstrating a rather high inter-family variation in personality The central 5-HT system is remarkably well conserved, functionally as well as anatomically, across the vertebrate subphylum It has been demonstrated that the 5-HT system influence genesis, differentiation and maturation of neuron cells in certain brain regions, control of sensory inputs, stimulus processing, and motor output, during early development The results presented in the current study raise questions regarding the paternal and maternal contribution to the co-variation between aggression and yolk size at emergence. Generally, egg size is determined by the mothers genotype combined with her environmental experiences In conclusion; larvae that emerge from the spawning nest with larger proportions of unconsumed yolk have a propensity to become socially dominant. A relationship which was present in siblings, suggests a link between interfamily variation in energy reserves and dominance in early emerging salmonid fish. Lower brain 5-HT levels in larvae with a propensity for social dominance is consistent with the general consensus that high levels of aggressive behavior are associated with low levels of brain 5-HT. Furthermore, that this variation in 5-HT was observed in individuals prior to the initial establishment of territories suggests that differences in aggression is mediated by a variation in 5-HT production and/or degradation, which is regulated by factors other than social environment. Social subordination during the initial defense of territory resulted in elevated 5-HT-ergic activity, which might effect the connectivity of the brain and the behavioral trait trajectories in individuals.