The family of aquaporins (AQPs), membrane water channels, consists of diverse types of proteins that are mainly permeable to water; some are also permeable to small solutes, such as glycerol and urea. They have been identified in a wide range of organisms, from microbes to vertebrates and plants, and are expressed in various tissues. Here, we focus on AQP types and their isoforms in astrocytes, a major glial cell type in the central nervous system (CNS). Astrocytes have anatomical contact with the microvasculature, pia, and neurons. Of the many roles that astrocytes have in the CNS, they are key in maintaining water homeostasis. The processes involved in this regulation have been investigated intensively, in particular regulation of the permeability and expression patterns of different AQP types in astrocytes. Three aquaporin types have been described in astrocytes: aquaporins AQP1 and AQP4 and aquaglyceroporin AQP9. The aim here is to review their isoforms, subcellular localization, permeability regulation, and expression patterns in the CNS. In the human CNS, AQP4 is expressed in normal physiological and pathological conditions, but astrocytic expression of AQP1 and AQP9 is mainly associated with a pathological state. Water homeostasis in the central nervous system (CNS) is tightly regulated, as even minute changes in extracellular volume affect ion concentrations and, consequently, neuronal excitability . DysreguAstrocytes are the only cells in the CNS that undergo rapid changes in volume ,7,8. TheNon-neuronal cells, which include astrocytes, outnumber neurons in some areas in the CNS, such as the neocortex . AstrocyAQPs have been identified in multiple mammalian tissues as well as in invertebrates, plants, and microbes . As theiThe strategic anatomical position of astrocytes with regard to water transport is, therefore, mirrored in the fact that all three CNS AQPs are expressed in these cells. We review these AQP types and their isoforms in respect of their expression patterns, intracellular localization, permeability regulation, and their role in normal physiological and pathological conditions.The AQP1 channel is primarily a water pore to facilitate transmembrane transport of water molecules driven by osmotic gradients . AQP1 waIn addition to the CPE, the expression of AQP1 was also confirmed in CNS astrocytes. However, in human astrocytes, its expression is mainly restricted to neuropathologic conditions, e.g., multiple sclerosis (MS), Alzheimer disease (AD), Parkinson disease (PD), and amyotrophic lateral sclerosis ,62,65. AMacaca fascicularis monkey .,80.79,80In general, the intracellular distribution of AQP4 in astrocytes is distinctly polarized, predominantly concentrated in the plasma membrane of glial processes close to or in direct contact with blood vessels, the ependymal layer, and pia ,85. HoweSeveral AQP4 isoforms are recognized in astrocytes AQP4a–f; , but theAQP4 gene revealed four additional isoforms besides the two classic isoforms: AQP4a (M1) and AQP4c (M23) [Xenopus oocytes, they failed to enhance water permeability through their plasma membrane [A thorough mapping of the rat 4c (M23) . Hence, 4c (M23) ), and AQ4c (M23) . The AQP4c (M23) . Plasma 4c (M23) . The latmembrane . HoweverXenopus oocytes, HeLa cell lines, human malignant glioblastoma cell lines, and in primary cultured rat astrocytes [Different AQP4 isoforms have distinct localization at the subcellular level. AQP4a (M1) and AQP4c (M23) are predominantly localized at the plasma membrane of perivascular endfeet regions of astrocytes. Although, in addition to their strong distribution in the plasma membrane, intracellular localization was also observed in cultured astrocytes ,90,95. Ltrocytes ,89,96,98trocytes . In additrocytes ,89,99. Itrocytes . Moreovetrocytes .Xenopus oocytes and in HeLa cells and all of them were shown to colocalize with GA and showed a broader cytoplasmic distribution [AQP4b, AQP4d, and AQP4f isoforms remained situated intracellularly when expressed in ribution . In cultribution . To undeIn addition to AQP4b, AQP4d, and AQP4f, another intracellular AQP4 isoform was described in skeletal muscle. This is alternatively spliced transcript named AQP4-Δ4 that lacks exon 4. AQP4-Δ4 lacks the final part of transmembrane helix 5 and loop E, which contains the second asparagine-proline-alanine (NPA) motif essential for the formation of the structural domain for water permeation in the aquaporin monomeric channel . NPA motA unique property of the AQP4 water channel is the formation of higher-order structures in the plasma membrane. First, monomers assemble into tetramers, which then aggregate into larger structures called orthogonal arrays of particles (OAPs) . OAPs haIn addition to AQP4a (M1) and AQP4c (M23), the AQP4e (Mz) isoform has also been proposed to assemble into OAPs, but only together with AQP4c (M23), similar to the AQP4a (M1) isoform ,98. TherKnowledge on the water permeability of AQP4 in astrocytes is scarce. In general, it is hypothesized that water permeability through AQP4 channels can be regulated at several levels. In brief, these are phosphorylation of the channel, expression and density of AQP4 channels at the plasma membrane, the rate of AQP4-laden vesicle delivery to the plasma membrane, and aggregation of AQP4 into OAPs.AQP4 has several potential phosphorylation sites , which mAnother factor that can affect water permeability through AQP4 in astrocytes is the abundance of AQP4 expression at the plasma membrane. Fast changes in the expression of AQP4 in the plasma membrane can be regulated by translocation of the channel to/from the plasma membrane via membrane-bound vesicles of the existing cellular AQP4 pool . HoweverIt is also hypothesized that the formation of OAPs in the plasma membrane can affect water permeability of the astrocyte plasma membrane. This could be achieved through differential assembly of OAPs in a post-Golgi phase governed by different expression levels of the isoforms that are also tissue specific ,123,124.AQP4 gene or to complementary proteins. For example, an extensive decrease in the abundance of AQP4 channels in the plasma membrane was detected in the perivascular plasma membrane of astrocytes in the hippocampal area of patients with epilepsy. This decrease was attributed to decreased expression of the AQP4 anchoring protein, even though AQP4 mRNA expression increased in the same reactivated astrocytes [Under several pathologic conditions, alterations in the subcellular distribution of AQP4 and its expression levels have been reported in astrocytes. The abundance of AQP4 in the plasma membrane has been observed to either decrease or increase, and it may be linked to altered expression of the trocytes ,126. Apptrocytes . Similartrocytes . On the trocytes ,69. Chantrocytes . Increastrocytes .In addition to neurodegenerative diseases, astrocytic AQP4 expression was upregulated in human tissue in several other pathologic conditions, such as edematous brain tumors and surrounding tissue, after subarachnoid hemorrhage, and in peritumoral tissue and ischemia ,131,132.Taken together, an extensive decrease of AQP4 expression in epilepsy patients likely results in perturbed water and ion homeostasis, leading to an increased propensity for seizures and cognitive decline . UpregulXenopus oocytes, human AQP9 was found to be permeable to a variety of structurally-unrelated solutes, including polyols , purines (adenine), pyrimidines (uracil and the chemotherapeutic agent 5-fluorouracil), and urea analogs (thiourea) [AQP9 is an aquaglyceroporin and is the least studied AQP in astrocytes. Like all aquaporins, it is permeable to water but also to small solutes. When expressed in hiourea) ,134,135.In mouse brain astrocytes, expression of AQP9 was observed in the processes bordering the subarachnoid space and ventricles, in the white matter, hippocampus, hypothalamus, and lateral septum . In addiSeveral AQP9 isoforms have been identified to date. For example, in astrocytes and in a subpopulation of neurons  isolated from rat brain, two AQP9 isoforms have been identified: ~25 and ~30 kDa isoforms. The ~30 kDa isoform is expressed in the plasma membrane and may correspond to the liver isoform (~32 kDa) or is possibly even a splicing variant. On the other hand, the ~25 kDa isoform  is expressed in mitochondria and is highly enriched in the inner mitochondrial membrane of astrocytes. Its major role could be the transport of lactic acid into the mitochondria, which would benefit cells in ischemic conditions .In general, AQP9 immunostaining in astrocytes was observed in their cell bodies, in processes directed toward blood vessels, and in perivascular endfeet; so it differs from AQP4 polarized immunolabeling ,63. In cSeveral functions of AQP9 in the CNS have been considered. AQP9 permeability to diverse molecules implies its role in diverse processes, such as water homeostasis and energy metabolism. Among several hypotheses, it was suggested that AQP9 may facilitate clearance of lactate and glycerol from the extracellular space, as is the case in cerebral ischemia . Given tAs in the case of AQP1 and AQP4, AQP9 can be regulated through phosphorylation, although only a few studies have investigated this. Experiments in cultured rat astrocytes suggest that signal transduction via PKC may decrease plasma membrane expression of AQP9 through PKC activation, and increase expression of AQP9 through the PKA-dependent increase of dbcAMP ,119.In addition, rendered plasma membrane expression of AQP9 was reported to be influenced by changes in mRNA expression. For example, an increase in mRNA and protein expression of AQP9 has been measured in human astrocytic tumors  compared with normal brain tissue . OverexpShort- and long-term permeability regulation of AQP9 in astrocytes remains to be elucidated.Changes in the permeability regulation and expression of AQP9 are hypothesized to play a role in the regulation of postischemia edema and in the clearance of lactate from the damaged tissue, as well as in the malignant progression of brain astrocytic tumors ,130.Three different AQP types have been identified in astrocytes. The most abundant among them is AQP4, which is also the most studied AQP type in the brain. Its expression has been confirmed in human and non-human mammalian brain astrocytes in physiological and pathological conditions. Despite its recognized general role in the regulation of brain water homeostasis, several issues remain to be elucidated, especially in light of newly-described isoforms, their roles, and permeability regulation. In addition to water permeability through the plasma membrane, AQP4 may be implicated in various other roles, such as cell adhesion, gas exchange, and possibly other roles, especially if we consider the growing body of data on different isoforms. Although AQP1 and AQP9 are expressed in physiologically normal tissue of non-human mammalian brains, it appears that, in human astrocytes, they are expressed mainly in pathological conditions. AQP9 is the least studied of all AQP types in astrocytes; its localization in human brain has been unambiguously confirmed only in astrocytomas so far. Variations in astrocytic expression patterns of different AQP types and their permeability properties suggest that they have different roles in maintaining brain homeostasis that need to be elucidated from the perspective of efficient pharmacological manipulation.


AbstractCymatiarogenhoferi (Fieber) and Cymatiacoleoptrata (Fabricius) . It is shown that the species have 2n = 33 (28A+2m+X1X2Y) and 2n = 24 (20A+2m+XY) respectively, post-reduction of sex chromosomes, and achiasmate meiosis of an alignment type in males. Cytogenetic and some morphological diagnostic characters separating Cymatia Flor from the rest of Corixidae are discussed.The karyotype and male meiosis, with a particular focus on the presence or absence of chiasmata between the homologs, were studied in the water boatman species  Corixoidea, known as water boatmen, are moderately large to small aquatic insects, belonging to the true bug infraorder Nepomorpha. According to Corixoidea include the only family Corixidae, with six subfamilies: Corixinae, Cymatiainae, Diaprepocorinae, Heterocorixinae, Stenocorixinae, and Micronectinae. Diaprepocorinae and Micronectinae to a family rank, meaning that Corixoidea is comprised of three families only: Corixidae, Micronectidae, and Diaprepocoridae. The validity of Micronectidae as well as for the corixid subfamilies Corixinae and Cymatiainae. In Micronectidae all four hitherto studied species were reported to have achiasmate male meiosis and no m-chromosomes: three species of Micronecta Kirkaldy, 1897 display 2n = 24 (22A+XY), while one species of Tenagobia Bergroth, 1899 has 2n = 30 (28+XY)  , the karyotype with 2n = 26 (24 + XY) was reported with no information on m-chromosomes and presence/absence of chiasmata in male meiosis (The  (28+XY) . In Cori0+2m+XY) . Cymatiaw Guinea . For the meiosis .Heteroptera, belonging to the infraorders Nepomorpha, Leptopodomorpha and Cimicomorpha  and Cymatiacoleoptrata , were studied. The focal point of this work was to clarify the presence or absence of chiasmata in spermatocyte meiosis of these species.In the present paper, the karyotype and male meiosis of other two Cymatiarogenhoferi and two males of Cymatiacoleoptrata were collected by light trap and hydrobiological net in different localities  in the field PageBreakimmediately after capturing. Males of Cymatiarogenhoferi were fixed in the field in 95% ethanol for subsequent sequencing, and the abdomen was transferred in 3:1 fixative for chromosome analysis, as it has been done recently by Cacopsyllamyrtilli  (Psylloidea). The gonads were dissected out and squashed in a small drop of 45% acetic acid. The cover slip was removed using dry ice. Slides were dehydrated in fresh fixative (3:1) and air dried. The preparations were stained using Schiff-Giemsa method  at 100× magnification and documented with a ProgResMFcool – Jenoptik AG digital camera. All preparations and remains of the specimens are stored at the Institute of Biodiversity and Ecosystem Research (IBER), BAS in Sofia, Bulgaria.metaphase I (MI), the bivalents laid parallel to the equatorial plane, with the homologous chromosomes facing opposite poles without any sign of chiasmata. Clearly, male meiosis of this species is achiasmate. Both MI and MII were radial  formed a ring with, a pair of very small and negatively heteropycnotic m-chromosomes inside. In contrast to MI, the MII ring was formed by 14 autosomes and one m-chromosome, while the sex chromosomes formed a pseudo-trivalent placed inside the ring. The Y chromosome was clearly larger than each of the two X chromosomes .The testes of the adult males were full of sperm, with a small number of well-synchronised dividing cells. No spermatogonial metaphases were observed. When condensing from a diffuse stage Figs , the autial Figs , 3. At MPageBreakCymatiarogenhoferi. Unfortunately, we found no second division stages in the two males explored here. When condensing from the diffuse stage , the bivalents were aligned parallel to the equatorial plane, with the homologous chromosomes facing opPageBreakposite poles without any signs of chiasmata. The MI plates were radial   Fig. , when thCymatiacoleoptrata was determined as 2n = 24 (20A+2m+XY).The chromosome formula of Cymatia and compare them with those encountered within the superfamily Corixoidea. This entailed at least four related issues, namely: 1) whether the karyotypes are conservative in respect to chromosome number and sex chromosome system, 2) whether m-chromosomes are present, 3) whether the post-reduction of sex chromosomes is present, and 4) whether the chiasmata are formed in male meiosis. Both Corixidae and Micronectidae are known to be characterised by an XY sex chromosome system and an inverted sequence of X and Y chromosome divisions in spermatocyte meiosis, i.e. the sex chromosome post-reduction . Meiosis is of a standard chiasmate type in males  scholtzi , Micronecta (Micronecta) poweri , and Micronecta (Micronecta) griseola HorPageBreakvath, 1899, each with 2n = 24 (22A+XY) (Tenagobia (Fuscagobia) fuscata , with 2n = 30 (28+XY)  and 2n = 24 (20A+2m+XY) respectively and achiasmate meiosis of an alignment type in males. In another Cymatia species, Cymatiabonsdorffi , studied by Cymatiainae share a presence of m-chromosomes with Corixinae, while the absence of chiasmata is shared with Micronectidae. Due to their very small size and negative heteropycnosis during meiosis, m-chromosomes are easily overlooked by researchers, and subsequently information about the distribution of these puzzling structures in different true bug taxa can hardly be used for inferences.In in males . Compare(22A+XY) , and in  (28+XY) . Based oMicronectidae from the infraorder Nepomorpha .The first  division involves several meiosis-specific events the most important being the formation of chiasmata, the points of genetic crossing-over, between homologous chromosomes. When meiosis is achiasmate and chiasmata are not formed, no diplotene or diakinesis stages can be recognised. The existence of achiasmate meiosis in phylogenetically unrelated true bug families, i.e. pomorpha , Saldidadomorpha , and in comorpha , argue fvolution . Consequate type . ComprehCymatiainae were erected for the first time as a separate taxon (as Cymatiini) in Corixidae on the basis of the shape and hairiness of the pala, the chitinisation of the pharynx, the length of maxillary stylets, and their position against pharynx  or a basal taxon (together with Diaprepocoridae) in the whole superfamily Corixoidea. It has repeatedly been shown that the absence of chiasmata during spermatocyte meiosis is evolutionarily stable in true bugs, and marks taxa at the rank of family (for references see Micronectidae (Cymatiainae from the rest of Corixidae. However, more comprehensive studies on morphological and cytogenetic aspects of Corixoidea as a whole are required to decide on the rank that should be assigned to Cymatiainae. The special focus must be on the genus Cnethocymatia from the same subfamily, the genus Diaprepocoris Kirkaldy, 1897 considered the most basal taxon of Corixoidea, and the genus Stenocorixa Horváth, 1926 showing morphological similarities with Cymatiainae (In different phylogenetic studies on rixoidea  the posinectidae  clearly nectidae , b. Bothnectidae  distinguatiainae .


In China, a growing number of adolescents have experienced traumatic events that have resulted in PTSD (post-traumatic stress disorder). Post-traumatic symptoms are common psychological problems in adolescents who have experienced traumatic events. However, existing studies tend to focus on the factors influencing PTSD, such as the response styles and social support, and studies on the relationships between parenting style, resilience and post-traumatic symptoms are still rare.To analyze the relationships between parenting style, resilience and post-traumatic symptoms among adolescents in China.A cross-sectional survey was conducted from June to December 2013 in the Liaoning Province, China. N = 5765 adolescents (aged 12 to 18 years old) were ultimately chosen to participate. The Chinese version of the Essen Trauma Inventory for Kids and Juveniles (ETI-KJ), a modified version of the Parental Authority Questionnaire, and the Chinese Resilience Scale were used to estimate the post-traumatic symptoms, parenting style, and resilience, respectively. Pearson’s correlations, multiple linear regression analyses and structural equation modeling (SEM) were applied to analyze the data.Of the adolescents, 39.76% (N = 2292) had been exposed to traumatic events during their lives. The prevalence of probable PTSD at the time of the interview  was 12.65%. Parenting style and resilience were significantly associated with post-traumatic symptoms. According to the SEM, parenting style had a significant direct effect on resilience  and post-traumatic symptoms , and resilience had a significant direct effect on the post-traumatic symptoms . Furthermore, parenting style had a significant indirect effect (-0.43×0.70 = -0.30. P<0.01) on the post-traumatic symptoms through resilience. The SEM significantly explained 49% of the variance in resilience and 30% of the variance in post-traumatic symptoms.Parenting style and resilience have significant effects on adolescents’ post-traumatic symptoms. Schools and social-related departments could share knowledge on the impact of parenting style with parents enabling them to improve their own parenting style and their children’s resilience and ability to respond effectively to traumatic events. PTSD is a commonly occurring disorder that often has a duration of many years and it is frequently associated with exposure to multiple traumatic events . In schoResilience is a psychological function whereby individuals recover after experiencing adversity or traumatic events using a successful response to a self-adjusting mechanism –9. It isIn the 1990s, researchers studied the effects of the family environment on child development by observing parent-child interactions. They proposed that parental behaviors influence children’s development through parenting styles. Baumrind noted that parenting styles could be divided into the following three types: permissive, authoritarian, and authoritative . It is iAccording to the aforementioned studies, resilience is related to post-traumatic symptoms, and parenting style is related to resilience. Therefore, we hypothesized that parenting style and resilience may be associated with post-traumatic symptoms. The aim of this paper is to investigate the degree of post-traumatic symptoms among adolescents in the Liaoning Province, China, and to estimate the synthesized relationship between parenting style, resilience and post-traumatic symptoms.A cross-sectional study was conducted in the Liaoning province. This investigation adopted a multistage stratified cluster random sampling method. Liaoning province includes 14 cities and is located in northeast China. According to the GDP ranking of Liaoning province in 2012, Shenyang city and Dalian city represent the highest level of socioeconomic development, Yingkou city and Jinzhou city represent moderate levels of socioeconomic development, and Liaoyang city and Tieling city represent the lowest level of socioeconomic development. For this study, 3 primary schools and 3 middle schools representing the average teaching and economic level of each city were randomly selected from each city. The students attending the 36 schools included in this study were considered to be representative of all adolescents in Liaoning province. Finally, we selected one entire class from each selected primary and middle school. In China, children in primary school grades 1–2 are too young to complete questionnaires and, as a result, they were excluded from the study.On the day before the questionnaires were distributed, with the agreement of the Liaoning Medical University ethics committee and the approval and assistance of the head teachers, we issued informed consent forms to each student to give to their parents. If the parents and students were willing to participate in the investigation, they wrote “agree” on the informed consent forms. The next day, we distributed our questionnaires to the students who had agreed to participate. First, we performed a preliminary investigation in Jinzhou city in May 2013. We randomly selected one primary and one middle school and issued questionnaires to the students who agreed to participate in our investigation. Five hundred thirty-five students participated, and 500 students responded effectively. Then, according to the multistage stratified cluster random sampling described above, we performed the community study from June to December 2013. We invited 6,500 students (aged 12 to 18 years old) to participate in this investigation; then, a total of 6,225 students agreed to participate in the study, and 5,958 responded (95.71% response rate); of these, 5,765 valid questionnaires were ultimately acquired (96.76% effective response rate).SD = 1.54 years). The number of adolescents per grade was 518 (22.60%) in sixth grade, 536 (23.39%) in seventh grade, 694 (30.28%) in eighth grade, and 544 (23.73%) in ninth grade. One thousand sixty-one (46.29%) of the adolescents were in a student cadre. Moreover, 914 (39.88%) of the adolescents were in inharmonious families, while 1378 (60.12%) of the adolescents were in harmonious families.Among those who responded effectively, 39.76% (N = 2292) had experienced traumatic events during their lifetime. One thousand one hundred two (48.08%) of the adolescent participants were male, and 1190 (51.92%) of the participants were female. The mean age of the adolescents was 12.45 years old  and PTSD. Section 3 asked about the students’ current (in the past four weeks) post-traumatic symptoms. The 23 items asked about intrusion (5 items), avoidance (7 items), hyper-arousal (5 items) and dissociation (6 items) rated on a 4-point Likert scale that ranged from “does not match at all” (0 points) to “completely matches” (3 points). The 24th item asked about possible somatic symptoms as well as the post-traumatic symptoms. Section 4 asked about when the post-traumatic symptoms began, how long they lasted and the pain caused by the traumatic events, using a 6-point Likert scale that ranged from “no pain” (0 points) to “extremely painful” (5 points). Looking at the interpersonal relationships, ability to learn, and hobbies, section 5 asked about the effects of post-traumatic symptoms on the students’ daily lives using a 4-point Likert scale that ranged from “no effect” (0 points) to “serious effect” (3 points).Part 2 was the Chinese version of the Essen Trauma Inventory for Kids and Juveniles (ETI-KJ), compiled by Tagay et al. , which wThe assessment of the post-traumatic symptoms was based on the total scores for the 23 items in section 3; the higher the score, the more serious the individual’s post-traumatic symptoms. According to the study by Tagay, on the premise of the 12 potential trauma events in section 1 meeting the DSM-IV A criteria 1 and 2, scores on the three dimensions of intrusion, avoidance and hyper-arousal that total more than 16 points are considered indicative of probable PTSD. Total scores over 35 on the four dimensions of intrusion, avoidance, hyper-arousal and dissociation are considered to indicate probable ASD.Section 1 of the ETI-KJ was used to screen those adolescents who had experienced at least one traumatic event, and section 3 assessed their post-traumatic symptoms. A study conducted in China showed that this questionnaire had good reliability (Cronbach’s α coefficient is 0.918) and validity . Using tPart 3 of our questionnaire used a modified version of the Parental Authority Questionnaire (PAQ) to assess the parenting style  . The oriPart 4 utilized the Chinese Resilience Scale to evaluate the students’ resilience . It was designed by Yueqin et al.  for ChinSPSS 17.0 and AMOS 17.0 were used for the statistical analyses. First, the descriptive analyses of the sociodemographic variables and types of traumatic events assessed were executed. Then, Pearson’s correlation coefficients were calculated to assess the relationships between the parenting style, resilience and post-traumatic symptoms. In addition, multiple linear regression was performed using the post-traumatic symptom score as the outcome variable and parenting style and resilience as continuous independent variables, controlling for age, gender, grade, student cadre, and family status. Finally, structural equation modeling (SEM) was applied to further verify the hypothetical relationships between several latent variables , and the process of parameter estimations could exclude measurement error. According to related research and theories, the hypothetical relationships model was created and is shown in Of the adolescents in this study, 39.76% (N = 2292) had experienced traumatic events during their lifetime. The one-month prevalence of probable PTSD  was 12.65% at the time of assessment. Of these 2292 participants, 312  adolescents were from Shenyang city, and among them, 95  adolescents were considered to suffer from probable PTSD. Three hundred eighteen (5.52%) students were from Dalian city, and among them, 95 (1.65%) adolescents were considered to suffer from probable PTSD. Three hundred forty-two (5.93%) students were from Jinzhou city, and among this sample, 96 (1.67%) adolescents were considered to suffer from probable PTSD. In Yingkou city 390 (6.76%) adolescents had experienced a traumatic event, and among them, 139 (2.41%) adolescents were considered to have probable PTSD. Four hundred fifty-seven (7.93%) adolescents were from Liaoyang city, and among them, 137 (2.38%) adolescents were considered to exhibit probable PTSD. Finally, 473 (8.20%) students were from Tieling city, and among them, 167 (2.90%) adolescents were considered to suffer from probable PTSD.The associations between the post-traumatic symptoms, parenting style and resilience in adolescents who went through traumatic events that were or were not independent of their parents may be different. Therefore, we performed a correlation analysis in different adolescent samples. Sample 1 (N = 562) consisted of adolescents who went through traumatic events that were dependent on their parents, while Sample 2 (N = 1730) consisted of adolescents who went through traumatic events that were independent of their parents. 1 in 1, multiple linear analysis in Model R2 showed that authoritative, authoritarian and permissive parenting styles were significantly associated with post-traumatic symptoms, and a total of 9.1% of the criterion variance was explained . Model R3 was run with the resilience dimensions added based on Model R2, and three subscales of parenting style and four subscales of resilience  were identified as significant relevant variables of post-traumatic symptoms.With post-traumatic symptoms as the explained variable and sociodemographic characteristics as the controlled variables, the parenting style and resilience dimensions were taken as principal significant variables by a thrice repeated multiple linear regression analysis. According to Model RTo identify a synthetic association between the post-traumatic symptoms, resilience and parenting style, we constructed the SEM with different samples. N = 562, consisted of adolescents who went through traumatic events that were dependent on their parents), sample 2 , sample 3  and sample 4  are included in This study revealed that the prevalence of probable PTSD among adolescents at the time of interview  was 12.65%, which was in line with another study  investigated in Shanghai, China . With reBased on the correlations between parenting style, resilience and post-traumatic symptoms in adolescents shown in 2 shows that the three different parenting styles had a significant influence on post-traumatic symptoms; the comparison between Models R2 and R1 shows that the parenting style explains an additional 8.5% of the variance in post-traumatic symptoms. For Model R3, the parenting styles and total scores on four of the resilience subscales (not positive thinking) significantly predicted post-traumatic symptoms. The comparison between Models R3 and R2 shows that resilience explains an additional 9.3% of the variance in post-traumatic symptoms.In Resilience has a negative predictive influence on the post-traumatic symptoms, which is in line with a previous study in south Asia . IndividThe SEM of the relationship between the parenting style, resilience, and post-traumatic symptoms is shown in The first limitation of this study was that the PAQ scale was modified in a way that might not have been standard and the study only used sections 1 and 3 of the ETI-JK scale. The second was that the participants were chosen only from the Liaoning Province because of time and convenience factors. The third was that the age bracket of the adolescents we investigated was 12–18 years old, which did not fully represent all adolescents in China. The last limitation was that the above three scales did not test the criterion-related validity with corresponding maturity scales. We will conduct future work that is aimed at addressing these issues.This paper discussed the relationship between post-traumatic symptoms, parenting style and resilience among adolescents. An authoritative parenting style enhanced adolescents’ resilience and their ability to respond effectively to post-traumatic symptoms, and authoritative parenting should be advocated for Chinese parents. Moreover, schools and society, as a whole, should transfer knowledge on the impact of parenting style to parents and establish and improve adolescents’ regulatory systems to protect and improve their physical and mental security.


The clusters were preformed in solution and covalently attached to the surface without any dispersion or aggregation. Comparison of the experimental images with simulations allowed the rotational motion, without lateral displacement, of individual clusters to be discerned, thereby demonstrating a robust covalent attachment of intact clusters to the graphene surface.Atomic-resolution transmission electron microscopy was used to identify individual Au Additional, and more accurate, corroboration came from X-ray photoelectron spectroscopy  results for GOSH and GOSH@Auormation . In bothopy XPS; , in whic , which complicates their identification. However, this functionalization density would correspond to an atomic content of 1.6±0.4 % Au, which is in close agreement with the TGA, XPS, and EDX measurements.Counting the Au9 clusters on GOSH. Using the known crystal structure of Au9, a tableau of multislice image simulations was constructed by rotating the molecule about two orthogonal symmetry axes , which scatter the electrons to a greater extent than do the phosphorus (Z=15) or carbon (Z=6) atoms. However, for accurate comparison all atoms were contained in the image simulation, including the coordination sphere of ligands and a section of graphene lattice.[9, each from an ac-TEM image acquired with 0.3 s exposure. The region in Figure 9 clusters , thus permitting exploration of the effect that the size and morphology of clusters have in applications ranging from biosensors or biomedicine, to energy storage, or heterogeneous catalysis.


Hepatitis B virus (HBV) infection is a major risk factor for the development of hepatocellular carcinoma (HCC) in China. At present, there still are 9.3 million chronic HBV-infected Chinese. Numerous studies have explored the association between possible factors and hepatocellular carcinoma risk, however, the results remains inconsistent. Therefore, we did this pooled analysis so as to get a precise result. Here, we took the chronic HBV-infected Chinese as the object. We systematically searched for studies evaluating whether the proposed factors changed HCC risk in PubMed, Chinese National Knowledge Infrastructure, VIP database and Wanfang data. Odds ratios (OR) with 95% confidence intervals (CI) were calculated by Review Manager 5.0 and publication bias was determined by Begg’s test and Egger’s test. In total, 3165 cases and 10,896 controls from 27 studies were included in this meta-analysis. Our results showed that pooled OR with 95% CI for each of the factors investigated were: non-antiviral treatment 2.70 , high HBV DNA levels 2.61 , alcohol consumption 2.19 , a family history of HCC 3.58  and male gender 2.14 , respectively. Our meta-analysis supports that high HBV DNA levels, non-antiviral treatment, alcohol consumption, a family history of HCC and male gender contributed to the risk of hepatocellular carcinoma in chronic HBV-infected Chinese from currently available evidence. Given the high prevalence of the non-antiviral treatment and alcohol drinking, behavior interventions for the two factors should be tackled first. Liver cancer, which consists predominantly of HCC, is the fifth most common carcinoma and the third most common cause of tumor-related deaths worldwide, leading to approximately 500,000 deaths every year ,2,3. In Considering the scale of the public health problem posed by HCC, over the past few decades, some measures have also been introduced to reduce the aflatoxin content in food and to reduce the lyngbya toxins in drinking water in China ,7,8. HowSince 1992, as part of an immunization project in China, hepatitis B vaccine has been used to inoculate in all newborns to effectively block mother-to-infant HBV transmission. However, the HBV infection rate remains high, with HBsAg carry rate of 7.2% for those aged between 1 and 59 years and 9.3 million chronic HBV-infected Chinese ,11. WherPrevious studies showed the modifiable risk factors included persistent high level of HBV replication, smoking and the habitual use of alcohol, however the effects of these factors were controversial ,38,39,40Meta-analysis is the implementation of statistical methods for combining and contrasting results from different studies to reduce random error and identify patterns or relationships in the context of a variety of evidence. In this study, we performed this meta-analysis to identify the true associations between possible factors and HCC risk.The data reported in our manuscript were cited from published literature, and had been approved by the ethics committee of Zhejiang provincial center of disease control and prevention (No.zjcdc-2015-1).All articles were retrieved from the following databases: Pubmed, Chinese National Knowledge Infrastructure (CNKI), VIP database and Wanfang data. Searches, using the search field “Title/Abstract”, were performed via using the search terms (“Chinese” or “China”) and (“hepatocellular carcinoma” or “liver tumors” or “tumor of liver” or “liver neoplasms”) and (“hepatitis b” or “hepatitis b virus”) AND (“risk factor”) from PubMed. Searches, using the search field “Abstract”, were performed via using the above-mentioned search terms from CNKI, VIP and Wanfang data journals published between January 1980 and October 2014.The present study was carried out following Meta-analysis in PRISMA guidelines .Only primary studies were included in our search. All eligible articles were case-control or prospective studies between January 1980 and October 2014. Eligible research articles not captured by the research strategies detailed above were retrieved by bibliography searches.Studies were included in the meta-analysis provided that: (1) the article reported a case-control or prospective study and had been accepted for publication with full text available; (2) all cases and controls were diagnosed by histopathological biopsy, or other national diagnostic criteria existing at that time, and possible risk factors were reported; (3) the article reported on chronic HBV-infected Chinese population (HBsAg as a marker of chronic HBV infection); and (4) the data to calculate OR with 95% CI was reported.Studies were excluded from the meta-analysis when: (1) The article reported other forms of viral hepatitis (hepatitis C or D) as the etiological agent; (2) The article did not provide a workable value for the main variable.To decide whether an article should be included or excluded, two independent reviewers carried out an assessment using a standardized data extraction form designed by our group. Data were extracted from each study by two separate investigators, and data about aflatoxin were not extracted because meta-analysis in the aflatoxin has been done . The litDiscrepancies between the decisions of the two reviewers were discussed. If a consensus was not achieved, the decision was made by a third reviewer. Articles were examined to eliminate duplicate reports of the same research.The following information was extracted from all of the acquired studies: the numbers of patients in each group, the characteristics of each group at baseline , and the study type. Definition of main outcomes: HCC, liver cirrhosis, CHB chronic hepatitis B and chronic HBV carries were diagnosed by the guidelines at that time ,44.p ≤ 0.1 the random-effect model was employed, and when p > 0.1 the fixed effects model was employed. In this meta-analysis, subgroup analyses were used to more thoroughly investigate the associations between different risk factors and HBV-related HCC, and Begg’s test and Egger’s linear regression test were also used to examine publication bias [p > 0.10), and the results of the Begg’s test were also not statistically significant . Analyses were performed using the software Stata version 9.0  and Review Manager 5.0 . The OR was not pooled when the number of OR of the risk factor were less than 5. All of the P-values were two-sided.The OR with 95% CI was used as the main outcomes to measure efficacy. Meta-analysis was performed using either the fixed-effect or random-effect model, depending on the statistical heterogeneity among studies as evaluated by Cochran’s chi-square test . Statistion bias ,47. The The selection of studies for inclusion in the meta-analysis was shown in According to the inclusive and exclusive criteria, all articles were retrieved and carefully reviewed to assess the eligibility. Twenty-seven eligible studies were identified after screening of 1161. A total of 27 studies, including 3165 cases and 10,896 controls were included in our research. Among the twenty-seven studies, following categories were studied: alcohol consumption 2180 cases), smoking 1432 cases), non-antiviral treatment (1094 cases), high HBV DNA levels 3831 cases), HBeAg positive 1592 cases), family histories of HCC (685 cases) and gender  3085 cases). The details of all of the studies evaluated in this meta-analysis are shown in 32 cases,92 cases,0 cases, 85 cases.31 cases,The available sample size of each study varied greatly, ranging from 80 to 11,893 objects. The mean age was greatly variable and the percentage of females also differed greatly see . The effects of non-antiviral treatment , alcohol consumption , smoking , high HBV DNA levels , HBeAg positive , family histories of HCC  and gender   on the development of HCC were investigated in this analysis and the results are shown in The pooled OR with 95% CI for the seven factors investigated were: non-antiviral treatment 2.70 , high HBV DNA levels 2.61 , alcohol consumption 2.19 , a family history of HCC 3.58 , male 2.14 , smoking 1.54  and HBeAg positive 1.25 , respectively.p < 0.10), and the random effect method was therefore used to pool the results for these factors. The heterogeneity test indicated that the variation of study-specific OR were not statistically significant (p > 0.10), and the fixed effect method was therefore used to pool the results for the other factors, and the conclusions remained largely unchanged when the random effect method was used. The results of statistical analysis and calculation are shown in The heterogeneity test indicated that the variation of study-specific OR for alcohol consumption, smoking, high HBV DNA levels, HBeAg positive, were statistically significant  have 2–4 times the risk of HCC development. The data do lead us to believe that controlling alcohol consumption might lead to decreases in HCC for some chronically infected Chinese. Since the proportion of the population with one or more of these risk factors is high in China, professional health education should be enhanced to promote cognitive and behavioral changes to reduce these harmful factors in society, and thus speeding up the process of preventing and controlling HCC. There is a high prevalence of non-antiviral treatment and alcohol drinking ,38,51,52In addition, this study showed that HBeAg positivity did not affect HCC development, and the results were different from those observed in previously reported ,33. A poThis study also showed that smoking did not affect HCC development, and the findings were also different from those observed in previously reported research . After oIt has previously been reported that age was a risk factor for HBV-related HCC development ; howeverHeterogeneity in the variation of study-specific OR for high HBV DNA levels and positive HBeAg was determined. One possible reason was that some cases had received antiviral treatment in three studies and four studies ,25,34,35This study has several limitations: (1) Some observational studies, retrospective studies and nonrandomized designs are susceptible to various biases such as inappropriate selection of subjects. These biases could have influenced slightly the internal and external validity of this study; (2) Although 27 eligible studies were included in our analysis, the sample for subgroup analysis was limited which could have affected the results; (3) Baseline data of all eligible studies such as observation time did not match well, and this could have underestimated the results; (4) Due to the low possible publication rate for negative studies, publication bias existed in some subgroup analyses of possible risk; (5) As the development of HBV-related HCC may be caused by multiple factors simultaneously, the interaction of factors may have contributed to the results. Due to data limitations, this article did not analyze this interaction.Our meta-analysis supports that high HBV DNA levels, non-antiviral treatment, alcohol consumption, a family history of HCC and male gender contributed to the risk of hepatocellular carcinoma in chronic HBV-infected Chinese from currently available evidence. Given the high prevalence of non-antiviral treatment and alcohol drinking, behavior interventions for these two factors should be tackled first.


GABAergic local circuit neurons are critical for the network activity and functional interaction of the amygdala and hippocampus. Previously, we obtained evidence for a GABAergic contribution to the hippocampal projection into the basolateral amygdala. Using fluorogold retrograde labeling, we now demonstrate that this projection indeed has a prominent GABAergic component comprising 17% of the GABAergic neurons in the ventral hippocampus. A majority of the identified GABAergic projection neurons are located in the stratum oriens of area CA1, but cells are also found in the stratum pyramidale and stratum radiatum. We could detect the expression of different markers of interneuron subpopulations, including parvalbumin and calbindin, somatostatin, neuropeptide Y, and cholecystokinin in such retrogradely labeled GABA neurons. Thus GABAergic projection neurons to the amygdala comprise a neurochemically heterogeneous group of cells from different interneuron populations, well situated to control network activity patterns in the amygdalo-hippocampal system. The ventral hippocampus has reciprocal connections with the basolateral amygdala ,2 and bomemories ,4,5. GABmemories ,7,8.e.g., in the septo-hippocampal system [i.e. the calcium-binding proteins parvalbumin, calbindin, and calretinin and the neuropeptides NPY, somatostatin, and cholecystokinin   aged 3–5® syringe, FG was injected unilaterally (n = 9) or bilaterally (n = 4) into the amygdala (anterior-posterior coordinates (AP) −1.8, medio-lateral coordinates (ML) ± 2.8, dorso-ventral coordinates (DV) −4). Because the projection is strictly ipsilateral, each injection of those four bilaterally injected animals was treated as a single case. This procedure revealed 17 successful injection cases into the amygdala  of Ketamin (10 mg/mL) and Xylazine (1 mg/mL). The retrograde tracer Fluorogold  was injected either using a Hamilton syringe or by means of iontophoresis into the amygdala. Using a 1-μL Hamiltondala cf. . In ordedala cf. b. One indala cf. a. To furAfter a survival time of 7–14 days, mice received a lethal dose of barbiturate  and were transcardially perfused with 30 mL 0.9% saline, followed by 200 mL of a mixture of 4% paraformaldehyde and 15% saturated picric acid in 0.1M phosphate buffer pH 7.4 (PB). Brains were dissected from the skull and postfixed for an additional 5 h at room temperature. All brains were shock-frozen at −40 °C in isopropanol and stored at −80 °C until cutting.Three to four series of coronal frozen sections (40 μm) were collected in cold PB. For chemical characterization of subpopulations of GFP-positive neurons, a series of sections was subjected to immunohistochemistry against either calcium-binding proteins parvalbumin , calbindin-D28k  and calretinin , and neuropeptides somatostatin ), neuropeptide Y , and Cholecystokinin . Sections were incubated in the primary antibody for 2 days at 4 °C, washed in PB, and incubated in the respective secondary biotinylated antibody . The peptides were visualized with avidin-Cy3 . Stained sections were mounted and coverslipped with Mowiol . For each antibody, we included a negative control section by omitting the primary antibody during incubation. In all cases, this resulted in a lack of staining.Sections of the ventral hippocampus were analyzed with a Zeiss Axioplan microscope equipped with fluorescence optics using appropriate filter sets for FG , GFP , and Cy-3 . A photomontage at low magnification (100×) from the region of interest , the percentage of GABAergic projection neurons was calculated for the population of retrogradely labeled neurons and the population of GABAergic neurons .Then, percentages of the GABAergic marker proteins within the population of double-labeled GABAergic were determined using the averages of double-labeled neurons (from injection cases set as 100%) and the averages of triple-labeled neurons determined from GABAergic marker cases a,b.® Version 9.3 .Due to the rather large injections, a contamination with tracer of the overlying cortex and striatum was always found. Spillover of tracer into the piriform cortex, a target of the ventral hippocampus  that borPressure injections of FG into the amygdala a resultei.e. the exclusive labeling in the ventral CA1 and subiculum, was exactly the same. Iontophoretic injections of FG into the amygdala b coveredThe small insets demonstrate a double labeled cell in the boxed area, respectively. However, numbers of labeled neurons in the hippocampus depend strongly on the location of the injection within the different nuclei of the amygdala , with thNumber of retrogradely-labeled neurons and number of double labeled neurons per section in the ventral hippocampus after iontophoretic injections of FG into different nuclei of the amygdala. BLv, basolateral nucleus of the amygdala ventral part; BLA, basolateral nucleus of the amygdala, anterior part; BM, basomedial nucleus of the amygdala ; CeL, central nucleus of the amygdala, lateral part; cp, cerebral peduncle; CPu, striatum; GP, Globus pallidus; ic, internal capsule; MePD, medial nucleus of the amygdala, posterodorsal part; VEn, ventral endopiriform nucleus.r = −0.024, p > 0.05, n = 8, Interestingly, the volume of injection sites and the number of labeled neurons did not correlate , indicating that adjacent areas overlying the injection  did not receive a substantial projection from the ventral hippocampus. Iontophoretic injections that were located within the striatum , absolute numbers of retrogradely labeled neurons varied between individual animals see . Howeverstriatum a, #1522 GFP-labeled neurons were more or less uniformly distributed in the ventral hippocampal area c, althoue.g. [To further classify the GABAergic neuron population that contributes to this projection see , we nexte.g. ).We regularly detected the calcium-binding proteins PV or the neuropeptides NPY, CCK, and SOM in FG/GFP double-labeled cells . CB-projGABAergic interneurons of the hippocampus comprise morphologically, physiologically, and neurochemically different subpopulations . They coImmunohistochemistry and tracing techniques are generally rather qualitative methods. In order to obtain an estimation of the proportion of GABAergic cell populations contributing to the hippocampo-amygdalar projection, we performed single large injections of retrograde tracer into the amygdala and determined the relative cell numbers of traced interneurons in the ventral hippocampus. This type of injection procedure inevitably contaminated overlying cortical and striatal structures that may contribute to the overall projection. Small iontophoretic injections into the striatum or the overlying cortex, however, revealed no labeling in the ventral hippocampus, suggesting that these structures are not the target of the ventral hippocampus. This was supported by anterograde tracing studies ,18,25,26Small iontophoretic injections into single amygdala nuclei  were fouA severe contamination of areas during pressure injections might be due to spillage of tracer into the piriform cortex which is situated lateral to the amygdala. This area receives a projection from the ventral hippocampus . HoweverThe current data confirm our previous observation of a GABAergic contribution to this projection . The larSuch an involvement in long-range interactions may be a more general feature, at least for some interneuron subpopulations in the hippocampus . GABAergGABAergic neurons in the hippocampus are critically involved in the generation and propagation of rhythmic network oscillations ,37, and It is likely that GABAergic projection neurons to the amygdala are similarly bound to specific hippocampal activity patterns. This may be relevant, in particular, for the formation and retrieval of emotional memories. The amygdala and hippocampus tightly interact in the formation of episodic memories and their modulation according to salience. For example, the ventral hippocampus and amygdala both mediate the effects of glucocorticoids on fear memory  and bothPrior studies showed that GABAergic mechanisms in the ventral hippocampus are involved in the mediation of context-specific fear memory retrieval after extinction . Thus, uet al. [Jinno et al.  have rep


Brachial-ankle pulse wave velocity (baPWV) is inversely associated with cognitive function. However, it is not known whether baPWV predicts cognitive decline (CD) in later life. We examined whether or not baPWV is an independent risk marker of subsequent CD in a population of older Japanese.Among 982 adults aged 65 years or older who participated in a baseline survey, 526 cognitively intact adults  were followed for a period of up to 5 years. Pulse wave velocity was determined using an automated waveform analyser. Cognition was assessed by the MMSE, and CD was defined as a decrease of two points or more on the MMSE.During an average follow-up of 3.4 years, 85 participants (16.2%) developed CD. After controlling for important confounders, the odds ratios for CD in the highest and middle tertiles of baPWV, as compared with the lowest tertile, were 2.95  and 2.39 , respectively.High baPWV was an independent predictor of CD in a general population of older adults and may be useful in the clinical evaluation of elders. It also affects the wellbeing of caregivers, who experience physical and mental stress during care, and is an economic burden due to the costs associated with providing social care. Alzheimer’s disease (AD) causes long-term pathological changes, and previous studies noted an association between the prodromal stage of AD and cognitive decline (CD). Wilson and colleagues2 reported that, compared with a group with no cognitive impairment, the annual rate of CD was more than doubled in a group with mild cognitive impairment and more than quadrupled in a group with AD. There is no established treatment for dementia; however, prevention or delay of CD might assist in limiting the onset of future dementia.Dementia is a growing public health concern worldwide. The World Health Organization estimates that the number of people with dementia will double by 2030 and more than triple by 2050.3 and nutritional biomarkers.4 Moreover, arterial stiffness (loss of cushioning capacity) was recently used as risk factor for CD in epidemiological and clinical studies. Arterial stiffness is associated with physical activity and nutritional status, is a marker of functional and structural changes in arteries, and can be assessed noninvasively using pulse wave velocity (PWV) measurement.5 Previous studies used carotid-femoral PWV (cfPWV), which measures the velocity of the pulse wave as it travels a given distance between the carotid and femoral arteries6 and reflects the stiffness of elastic arteries.7 A high cfPWV was significantly associated with marked declines in psychomotor speed,8 verbal learning, and nonverbal memory9 in older adults. Scuteri and colleagues10,11 reported an association between cfPWV and CD among older adults who reported memory problems and were assessed using the Mini-Mental State Examination (MMSE). However, no independent association was found between cfPWV and CD in the Rotterdam Study.12We previously reported several independent risk markers in CD incidence, including lower physical performance7 This method was developed to assess pulse wave transmission between the brachial and tibial arteries13 and reflects stiffness in both muscular and elastic arteries.7 The baPWV technique has good reproducibility, even when not performed by highly skilled technicians, and is not time-consuming. Earlier cross-sectional studies found that baPWV was inversely associated with cognitive function among Japanese aged 70 years or older14 and 85 years.5 However, the longitudinal association between baPWV and CD has not been investigated among community-dwelling elderly individuals. Furthermore, whether or not arterial stiffness is associated with CD after adjustment for sociomedical factors is unknown.Although cfPWV is regarded throughout the world as the gold standard for measurement of arterial stiffness, brachial-ankle PWV (baPWV) measurement is more frequently used in Japan.A better understanding of the relation of arterial stiffness to CD risk might yield new insights regarding physiological mechanisms during the prodromal stage of dementia. In this prospective study of community-dwelling older adults, we measured baPWV and health-related factors, including measures of physical performance, nutritional biomarkers, chronic diseases, and apolipoprotein E (APOE) genotype, at baseline. We then used the MMSE to follow the cognitive function of participants. The objective of the study was to determine whether baPWV was independently associated with CD after adjustment for potential confounders.3,4 All participants provided written informed consent under conditions approved by the Ethics Committee at Tokyo Metropolitan Institute of Gerontology. Baseline assessments were performed from 2008 through 2011 at the same local public health center. Annual follow-up assessments were conducted in the same manner from 2012 through 2013. To be eligible for the study, individuals had to complete the baseline assessment at least once. Among the 2313 elders with valid and complete baseline data, 982 were selected for participation in the present study. Ultimately, data from 526 adults who had completed both baseline and follow-up assessments were analyzed, as shown in Figure n = 456) were operationally defined as mild cognitive impairment at baseline , death (n = 59), need for care under the Long-term Care Insurance program (n = 65), relocation (n = 52), and unknown reasons (n = 251).Data were collected as part of a comprehensive health examination conducted in Kusatsu Town, Gunma Prefecture, Japan. In addition to an annual preventive health check-up, for residents aged 40 years or older, participants aged 65 years or older underwent a geriatric assessment that included measurement of baPWV and cognitive function. The details of the study design have been previously reported.14–18 Briefly, cuffs wrapped around the brachia and ankles were connected to a plethysmographic sensor, which determined the volume pulse form, and an oscillometric pressure sensor. Pressure waveforms were recorded simultaneously at the brachial and tibial arteries to determine the time interval between the initial rise in the brachial and tibial waveforms. The path length from the suprasternal notch to the elbow (ΔDa) was obtained from superficial measurements and was estimated using the equation ΔDa = 0.2195 × H − 2.0734, where H is the height of the participant in centimeters. The path length from the suprasternal notch to the ankle (ΔDb) was calculated as ΔDb = (0.5643 × H − 18.3810) + (0.2486 × H − 30.7090). The baPWV was calculated as the mean of the values from the left and right sides, and the data were divided into tertiles  in the analysis.The baPWV (cm/sec) was measured with an automatic waveform analyzer . This technique has been described in detail elsewhere.3,4 The score ranges from 0 to 30, with lower scores indicating poorer global cognitive function. A decrease of at least two points on the MMSE during the follow-up period was defined as CD.19–21Cognitive function was assessed using the MMSE, which was administered by well-trained personnel.22Blood testing included white blood cell (WBC) count, red blood cell count, hemoglobin, hematocrit, mean corpuscular volume, hemoglobin A1c, total cholesterol, high-density lipoprotein cholesterol, triglycerides, creatinine, and albumin. Nonfasting blood samples were collected using standard procedures. Samples were analyzed at the Sannaikai Clinic, which is regularly monitored by several domestic authorities. APOE genotyping was performed on coded DNA specimens by technicians blinded to the diagnosis. The categorical variable APOE was classified by genotype as ε2ε2, ε2ε3, ε2ε4, ε3ε3, ε3ε4, and ε4ε4.23 body height and weight, body mass index (BMI), resting blood pressure, ankle-brachial pressure index (ABI), grip strength, usual and maximum gait speeds, Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC), Geriatric Depression Scale (GDS) Short-version, and years of follow-up. Well-trained personnel interviewed the participants.The covariates included sex, age, years of education, living arrangement, frequency of going outdoors, history of chronic diseases and antihypertensive drug use,Chronic diseases included clinically relevant medical conditions: hypertension, hyperlipidemia, cerebral vascular disease , heart disease , and diabetes mellitus. For each condition, participants were asked whether a physician had diagnosed the specific condition (yes or no).24; participants were asked to squeeze the handle as hard as they could. Gait speed was measured over a straight 11-m walkway marked with tape at 3 m and 8 m.25,26 Participants were asked to walk at their usual and maximum pace, and well-trained staff measured the time required to walk 5 m and calculated gait speed (expressed as m/sec). Usual gait performance was measured once. Grip strength and maximum gait speed were measured twice, and the better of the two results was recorded.Grip strength (kg) was measured in the dominant hand using a standard hydraulic handgrip dynamometer27 was designed to measure higher-level competence in older community residents. The score ranges from 0 to 13, with higher scores indicating higher functional capacity.The TMIG-ICU test and chi-square test were used to compare baseline sociomedical characteristics between individuals who developed CD during follow-up and those who did not. We used logistic regression plot to predict the probability of occurrence for subsequent CD with baPWV adjusted for sex, age, and follow-up year. The dataset for the present study does not include censored data, and the effect of baPWV at baseline on subsequent CD would not change during the follow-up period. Thus, we used multiple logistic regression models to examine independent associations between measures of baPWV at baseline with subsequent CD. We adjusted for confounding factors using multiple logistic regression models in which baPWV was defined as the independent variable, and subsequent CD was defined as the dependent variable. Some continuous variables were divided into tertiles as a covariate.The Mann-Whitney P < 0.05.Four models were used. The first was the crude model (model 1). In the second, the covariates were sex, age, and follow-up year (model 2). Model 3 included the covariates in model 2 plus all factors that were significantly associated with CD in univariate analysis. In model 4, antihypertensive medication, systolic blood pressure, high-density lipoprotein cholesterol, albumin, and APOE genotype were added as important covariates. We excluded some factors, to avoid multicollinearity among covariates. The statistical models were run separately. Statistics were computed using SPSS  and SAS , and the level of significance was set at Among study participants at baseline, average (standard deviation [SD]) age was 71.7 (5.6) years, 57.8% were women, 22.5% lived alone, 13.2% had 13 or more years of education, 54.8% had maximum scores on the TMIG-IC, and 87.3% had a score of 26 or higher on the MMSE. Chronic diseases included clinically relevant medical conditions; 36.3% had hypertension (33.5% used antihypertensive drugs), 21.5% had hyperlipidemia, 4.0% had cerebral vascular disease, 11.4% had heart disease, and 10.3% had diabetes. The average (SD) baPWV (cm/sec) was 1782 (362).During a mean follow-up of 3.4 years, 85 of 526 16.2%) adults developed CD. Table 6.2% adulFigure 5,14 reported an association between baPWV and cognitive function; however, the longitudinal association with CD has not previously been studied. The present prospective study of community-dwelling older Japanese is the first to show that baPWV is an independent predictor of CD, as assessed by MMSE, after adjusting for potential confounders.Recent cross-sectional studies5,14,28–31 In the present study, baPWV was independently associated with CD after adjustment for blood pressure level and use of antihypertensive medication. Furthermore, one study found that a baPWV value in the highest quartile was a significant predictor of progression to higher blood pressure categories,32 which suggests that arterial stiffness develops before hypertension.13,33Studies have revealed several pathways between arterial stiffness and cognitive function. Most importantly, higher blood pressure level may have a key role in CD.33 which might accelerate narrowing of cerebral vasculature, leading to chronic hypoperfusion8 and ischemia. The resulting state of chronic hypoperfusion may impede delivery of energy substrates and nutrients to active brain cells and directly injure cerebral white matter or allow toxic metabolic byproducts to accumulate within the brain and blood vessels.34 In addition, ischemia may lead to accumulation of amyloid precursor protein and accelerated formation of free oxygen radicals, as has been seen in animal experiments.35 Second, certain diseases might have mediating roles in the pathophysiology of CD. Hypertension induced by arteriosclerosis may lead to thickening of the cerebrovascular endothelium and endothelial dysfunction and contribute to thrombosis and microinfarcts.8,36 Moreover, dysfunction in the blood-brain barrier could be important in CD. Concurrent breakdown of the blood-brain barrier may allow toxins, proteases, or other substances in the blood to enter the brain interstitial space and injure surrounding neurons and glial cells.8,37 Other studies have reported a significant positive relationship between arterial stiffness and volume or localization of white matter lesions, a known predisposing factor for dementia. A higher PWV was significantly associated with a greater volume of white matter hyperintensities on neuroimaging.38–40The present evidence suggests two mechanisms by which baPWV may predict CD development through higher blood pressure. First, blood flow disturbance may contribute to CD. Lower arterial elasticity leads to hypertension,20 In univariate analysis, CD was closely associated with age, years of education, frequency of going outdoors, usual and maximum gait speeds, WBC count, MMSE score, years of follow-up, and baPWV, and marginally associated with systolic blood pressure and pulse pressure. Andrew and colleagues41 found that increasing social vulnerability was associated with CD, and Saczynski and colleagues42 reported that a decline in social engagement between mid- and late-life was predictive of incident dementia. Further research is thus needed to explore the associations of social factors, such as frequency of going outdoors, with CD. Our findings support previous results on gait and cognitive function.3 Although a cross-sectional study found an inverse association between WBC count and psychomotor cognitive performance in the elderly,43 longitudinal associations have not been examined. Further study is necessary to examine the independent association of WBC count with CD, after controlling for cytokines and factors derived from leucocytes. In previous studies, the association between higher MMSE scores and CD was attributed to a ceiling effect.3,4 Several studies have shown that the ε4 allele is a risk factor for cognitive impairment and decline44–46; however, no studies found an effect of APOE genotype on cognitive functioning.47–49 The present findings are comparable to those of previous investigations, which indicates that our study population was not unusual.The incidence rate of CD was 16.2% during a mean follow-up of 3.4 years. This value is compatible with previous results.14,50 We evaluated PWV using baPWV, which might be more relevant and practical in clinical settings, thus facilitating screening of persons at high risk.This study has several strengths. First, we assessed a number of sociomedical factors and included them in statistical models, which revealed that baPWV was significantly associated with CD even after adjusting for sociodemographic factors, disease status, physical performance, nutritional status, social activities, and genotype. Second, PWV, as defined by the arterial radius and thickness of the arterial wall, can be used as a direct marker of arterial stiffness.51 A comparison of those followed-up (n = 526) and those excluded from the analysis (n = 456) showed that the latter had higher baPWV values and worse MMSE scores at baseline. This limitation may have attenuated the association between baPWV and CD. Second, cognition was assessed only with the MMSE. Although the MMSE is a convenient measure of global cognition, other instruments are available for such assessment. Further study is needed to explore the association of baPWV and other measures of CD .52Several limitations of this study should be noted. First, the participants were healthier than the general elderly population in Japan due to the “healthy volunteer effect”.In conclusion, this prospective study found an association between higher baPWV and CD among community-dwelling older Japanese, even after adjusting for potential confounders. Stiffness in elastic arteries has been used as a marker of subsequent CD. Our findings suggest that stiffness in both muscular and elastic arteries is also a marker for subsequent CD, as it reflects disturbances in blood flow and/or the effects of certain diseases. These results may aid in risk assessment of elderly adults and might be useful in early screening for dementia.


Background. Systemic capillary leak syndrome (SCLS) is a rare disorder characterized by unexplained, recurrent episodes of transient, abrupt increase in endothelial permeability, leading to severe hypotension, generalized edema, and hemoconcentration. Case Report. We report the case of a patient suffering from systemic capillary leak syndrome and present a possible interpretation of the pathophysiology of this condition. Besides the classical triad of hypotension, edema, and hemoconcentration, we recorded increased levels of methemoglobin, an index of NO overproduction. We present a possible interpretation of the pathophysiology of this condition based on the fast and complete reversal of symptoms after methylene blue administration (which opposes NO-induced effects) and speculate that increased NO levels could be implicated in the pathophysiology of the capillary leak phase. Why should an emergency physician be aware of this? The safety of this treatment and its fluid- and cathecolamine-sparing effect deserve consideration and further research. Systemic capillary leak syndrome (SCLS) is a rare disorder characterized by unexplained, recurrent episodes of transient, abrupt increase in endothelial permeability, leading to severe hypotension, generalized edema, and hemoconcentration . Both etWe describe the improvement of one patient with SCLS in two occasions with acute IV administration of methylene blue after failure of the medications commonly used in this setting. We present a possible interpretation of the pathophysiology of this response to therapy.κ peak. An empirical course of broad-spectrum antibiotic and furosemide was started.In March 2013, a 56-year-old man, otherwise healthy, suffered from a cold and low-grade fever and gradually developed oliguria and weight gain. The general practitioner prescribed some biochemical tests, which resulted normal except for serum albumin 3 g/dL and a monoclonal IgG/3, PaCO2 37 with RR 18/min, core body temperature 36.4°C, HR 120/min), the case was interpreted as refractory septic shock of unknown origin (cultures later resulted negative), and empirical treatment with methylene blue (1.5 mg/kg IV bolus over 1 hour) was given. Soon after the end of the infusion, ABP rose to 140/80, HR 75/min, diuresis restarted, and norepinephrine was suspended in 2 hours. Renal function improved and edema and effusions reduced. The patient was discharged home with no therapy, whilst awaiting more tests.Ten days later, he developed massive peripheral edema, bilateral pleural and pericardial effusion, and ascites. Body temperature was normal, arterial blood pressure (ABP) was 90/60, and heart rate was (HR) 120/min. Blood tests showed albumin 2.3 g/dL, creatinine 1.4 mg/dL, sodium 129 mEq/L, hemoglobin (Hb) 22 g/dL, and hematocrit (Ht) 62%. Crystalloid loading was started, but despite a positive balance of about 7000 mL over 12 hours, ABP kept falling down to 70/40 and the patient became anuric. Norepinephrine (NE) up to 0.2 mcg/kg/min was then added, with ABP only rising to 80/60. Despite the presence of only tachycardia as a SIRS sign  showed increased levels . The recurrence of episodes of hypotension, hypoalbuminemia, and hemoconcentration and the presence of a monoclonal IgG/In October 2013, the patient again experienced symptoms of a cold similar to those before the first admission. On arrival to the hospital, he was hypotensive and tachycardic; blood tests  showed sGiven the lack of response to treatment, bearing in mind the previous anecdotal response, methylene blue was administered (1.5 mg/kg IV bolus over 1 hour), and ABP again rapidly rose to 135/90, allowing for NE termination 8 hours later. Urine output gradually increased, allowing for the negativization of fluid balance and concurrent recovery of renal function. Haemoglobin levels normalized over a 48-hour period, while albumin remained low . The patWe describe a case of SCLS that responded twice—one time as a rescue for a suspected diagnosis of septic shock, while the second time intentionally to the administration of methylene blue. In both episodes, the patient had hypotension (with ongoing further reduction during the first 12 hours) and signs of severe haemoconcentration  and needed significant amount of NE, despite positive fluid balance of >5 liters in 12 h, in line with the well-known poor response to fluid and vasoactive drugs of SCLS [Actual management of the acute shock phase in this condition is based on support of vital functions with IV fluids, including colloids and vasopressors . We avoiDespite severe hypotension, the patient was awake and cooperative; moreover, hypoxemia was not present ad admission, and the lung CT scan excluded pulmonary edema. Usually, during SCLS attacks, musculature and connective tissue are the principal target sites of the extravasation of plasma, while the lungs, brain, and kidneys seem to be infrequently involved ; as suchκ or IgA-κ monoclonal gammopathy [λ or IgA-λ, was excluded by the absence of any sign of polyneuropathy.This patient, as the majority of those described in series and case reports, presented a monoclonal gammopathy  and elevmmopathy : both muThe patient was also in long-term treatment with theophylline , a drug The response to methylene blue supports the hypothesis that increased NO levels could be implicated in the pathophysiology of the acute capillary leak phase. Methylene blue -phenothiazin-5-ium chloride) is generally used in the setting of methaemoglobinemia  and prov in vitro [ in vivo conditions, this time may even increase, depending on plasma redox state.Although multiple therapies were administered during the clinical management of the patient, both times we recorded a clear temporal relation between methylene blue administration and reversal of the symptoms, leading us to identify this treatment as the main cause for the change in the clinical course. We did not report direct measures of NO levels in the case we described. Indeed, NO has a very short half-life . Howeverin vitro ; under iAt pharmacologic doses methylene blue is a reducing agent via the NADPH-methemoglobin reductase pathway . MethyleThe main limit of the present investigation is its case-report nature. However, the rarity of this condition makes experimental studies difficult to plan, and the incomplete understanding of the underlying mechanisms does not allow for preclinical modeling. Moreover, the hemodynamic response to methylene blue might have simply faced by chance the natural course of the syndrome, which spontaneously reversed. However, the response we observed was similar in two different occasions, and both times it occurred soon after the administration of the drug.SCLS is a rare yet potentially severe condition, often difficult to recognize and diagnose upon initial presentation. Current therapies are mainly supportive, and the condition is still associated with a 10-year mortality rate of about 30% , along w


Background: Progressions in science and technology have generated several methods for delaying preterm delivery and abortion; therefore, discovering an easy, non-invasive, practical, and non-expensive predictive factor can help us to perform preventive methods in healthy pregnant women, without any risk factors.Objective: To indicate an appropriate index for predicting abortion in early pregnancy.Materials and Methods: In a prospective study, 73 pregnant women who had a singleton pregnancy, had no complications or history of abortion or disease, and were referred to Mahdieh and Taleghani Hospitals between 2007-2009, were evaluated. Blood and cervical fluid samples were obtained thrice from all patients: at the first visit, after 1 week, and 1-2 weeks later. They were followed up until the 12th week of gestation.Results: Using the receiver-operator characteristic (ROC) curve analysis, 1.62 was obtained as the cut-off point for the cervical fluid: serum human chorionic gonadotropin concentration ratio; 14 patients (19.2%) experienced abortion, and 12 women (70.6%) had a ratio ≥1.62. Of the pregnant women with a ratio of <1.62, 3.6% had an abortion.Conclusion: Pregnant women who do not show any signs of abortion and have a high cervical fluid: serum HCG concentration ratio are at risk of abortion; therefore, the cut-off point might be an appropriate index for predicting abortion in early pregnancy. The overall incidence of abortion is about 10-15% of pregnancies . AlthougPrevious studies have evaluated various factors for predicting miscarriage, each introducing a different factor; pregnancy-associated plasma protein A (PAPP-A) , 5; macrHowever, their use is clinically limited because advanced technology is needed for performing methods based on these factors . Althouget al a new concept was suggested for predicting miscarriage during early pregnancy, i.e., the cervical fluid: serum HCG concentration ratio  would be beneficial. In a study by Takata on ratio . The preIn a prospective clinical study, 73 pregnant women who had a singleton pregnancy, had no complications or history of abortion or disease, and were referred to the prenatal clinics of Mahdieh and Taleghani Hospitals between October 2007 and April 2009 were evaluated during gestational weeks 4-12. This study was approved by the ethics committee of Infertility and Reproductive Health Research Center (IRHRC) at Shahid Beheshti University of Medical Sciences. A written consent was obtained from all patients after they were explained the aim and different steps of the study, and no extra expenditure was imposed on them. oC. Moreover, a cervical sample was obtained by washing the vagina and ectocervix with warm saline and rotating a cotton swab 2 times in the vaginal canal; the sample was diluted in 1 mL buffered-sulfate solution and centrifuged at a rate of 1000 rpm for 10 minutes. Supernatant was collected and stored at -30oC until the cervical fluid HCG concentration was determined using the ELISA test. The second blood and cervical samples were collected after 1 week, the third 1-2 weeks later, and if necessary, at the following visits. At the first visit, all patients underwent a routine pelvic examination and gave a blood sample for determination of the serum HCG concentration by using an enzyme-linked immunosorbent assay (ELISA) test. This sample was coagulated at room temperature, separated by centrifugation, and maintained at -30The levels of serum and cervical HCG were determined with a commercial enzyme immunoassay kit  company, Ontario, Canada; CV=5.2%, sensitivity: 0.7 IU/l). Gestational age was determined based on the LMP and transvaginal sonography during the first trimester. All patients were followed up every 3 weeks, and they received phone consultation. If they developed symptoms such as pain, bleeding, or spotting, or if any signs of abortion were observed, such as cervical dilatation and effacement confirming the diagnosis of unpreventable abortion samples, they were excluded from the study. If the patients were absent during the definite visit time, they were followed up by a phone call, and if they did not wish to continue being part of the study, they were excluded. In addition, during the study, if the patients developed any other complications of pregnancy, they were excluded from the study.Statistical analysisData analysis was performed using the SPSS software version 15.00 for Windows, and an independent sample t-test was used for comparison of the 2 groups.Seventy-three pregnant women who were at 4-12 weeks’ gestation and were referred to our center were evaluated. The mean gestational age was 8 weeks (w) ; the distribution is shown in th gestational week, 59 women (80.8%) had a normal pregnancy, and abortion occurred in 14 cases (19.2%). Of those who had an abortion, 12 of 14 patients (70.6%) had a ratio ≥1.62, whereas only 3.6% of women having a ratio <1.62 experienced abortion. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the cervical fluid: serum HCG concentration ratio as a predictor of abortion are indicated in The present study is the second study on the accuracy of the cervical fluid: serum HCG concentration ratio in predicting the probability of miscarriage in early pregnancy. We analyzed the relationship between cervical and serum HCG concentration. Similar to a study performed in Japan in September 2005 . In thiset al . According to the results of the present and previous studies , it shouTherefore, it could be an appropriate, practical, non-expensive, and available index for predicting the probability of early miscarriage. Use of this index can result in early diagnosis of abortion in the first trimester, giving physicians more time for determining the probable cause of abortion and for performing preventive methods such as hormonal support for better reassuring patients. It is suggested that further studies with larger sample sizes should be designed, even for patients experiencing recurrent abortions.


Introduction. Nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) represents a risk for the spread of bacteria. This study characterized the S. aureus isolated from medical students, who were in their clinical rotation at a hospital in the city of Cali. Materials and Methods. 216 students participated in the study and 63 isolates of S. aureus were evaluated for susceptibility and PCR amplification of agr and mecA genes. The origin of MRSA isolates was established by analyzing agr polymorphisms. Results. A total of 29.2% of students were colonized by S. aureus and nasal carriage rate was 23.6% and 14.3% MRSA. Three agr groups  were identified; the agr I group was the most common, with a 35% prevalence; this group is from community origin. Conclusion. The present study demonstrates that medical students carry S. aureus strains, with the threat of spreading them both to community and hospital environments. Staphylococcus aureus resistant to methicillin (MRSA) is currently among the bacteria of global concern [ mecA gene; these strains can simultaneously acquire pathogenicity genes that make them able to develop more aggressive infections [ concern , 2. It i concern –5 and at concern , 6. The fections . S. aureus in healthy individuals has been shown to have a high prevalence, especially in children, young adults, and healthcare workers [Asymptomatic carriage of workers –10. Medi workers . S. aureus colonization from 20 to 60% in health area students [Epidemiological studies conducted in Latin American hospitals report a prevalence ofstudents –13, withstudents –16. S. aureus carried by the healthcare staff is of intrahospital origin or from the community and how it is disseminated in hospital wards.Epidemiological knowledge of the status of MRSA strains circulating in our environment helps to establish control measures to prevent the transmission of the pathogen through adequate use of biosafety barriers by the healthcare staff, including medical students. In this sense, two of the aspects that must be considered are whether the agr genes, have permitted determining the variability and origin of isolates generating epidemic outbreaks. According to this gene's variability pattern, to date, four variants have been defined, denominated as groups I to IV [Molecular approaches, like analysis of the polymorphism in I to IV . Isolate I to IV , 19. S. aureus and detect the presence of the mecA gene in strains isolated from asymptomatic medical students who were in their clinical rotation phase in a hospital in the city of Cali.The objective of this study was to establish the genetic diversity of isolates ofDuring the study, 481 medical students were in their preclinical and clinical rotation cycle; 216 students signed the informed consent and fulfilled with the inclusion and exclusion criteria, which included not having received antibiotic treatment within the last three months and not presenting respiratory or skin diseases. A total of 119 participants were women and 97 were men who were in hospital practices from October to December 2010 at the San Juan de Dios Hospital in the city of Cali. A cross-sectional descriptive study was carried out and it was evaluated and approved by the Ethics and Bioethics Committee of the Faculty of Health at the university.Samples were taken with sterile cotton swabs through smears of the nasal mucosa and of the skin in each student. The samples were processed immediately in the microbiology laboratory. The isolates were managed by codes, thus, respecting student confidentiality. Staphylococcus genus, the samples were seeded in mannitol salt phenol red agar  and incubated for 24 to 48 hours at 37°C. Identification of S. aureus was accomplished through fermentation of mannitol in selective agar (medium yellow coloration), the positive reaction of coagulase test, and microscope observation of Gram positive cocci in clusters from a direct extended Gram stain. The S. aureus was differentiated from coagulase-negative staphylococci (CoNS) by using the DNase test.To isolate species of theAntimicrobial susceptibility testing was conducted on paired samples using the agar disc diffusion method following the recommendations of the Clinical and Laboratory Standards Institute (CLSI) . S. aureus was inoculated (standard 0.5 by Mc Farland) in Mueller-Hinton agar medium (Scharlau Chemie S.A.) and then the sensi-disks were placed: oxacillin , cefoxitin , cephalexin , gentamicin , ciprofloxacin , erythromycin , clindamycin , trimethoprim/sulfamethoxazole (SXT 1.25/23.75 μg), tetracycline , chloramphenicol , vancomycin , imipenem , and penicillin  (Oxoid). To verify the action of the sensi-disks, during susceptibility analysis the ATCC 25923 strain of S. aureus was used as control.To conduct this test, a standardized amount of mecA gene [Determination of MRSA isolates was performed according to the results obtained in the evaluation of oxacillin and cefoxitin and by detecting theecA gene , 22.The DNA of the reference strains and of the bacterial isolates was extracted by using the modified protocol by Cheng and Jiang, based on bacterial lysis using 25% sucrose, 10 mg/mL of lysozyme, and 1 mg/mL of Proteinase K, at 56°C . mecA gene was amplified, following the protocol reported by Lee and colleagues using primers: MR1, 5′ (478)-GTG GAA TTG GCC AAT ACA GG-(497) 3′, and MR2, 5′ (1816)-TGA GTT CTG CAG TAC CGG AT-(1797) 3′ [To establish resistance to methicillin, the1797) 3′ . agr groups, fragments of 440 bp, 572 bp, 406 bp, and 588 pb, respectively, were amplified independently using a set of primers, made up of the universal sense primer, with the agr gene sequence, 5′-ATG CAC ATG GTG CAC ATG C-3′, and one of the specific primers for each group in antisense, agr I 5′-GTC ACA AGT ACT ATA AGC TGC GAT-3′, agr II 5′-GTA TTA CTA ATT GAA AAG TGC CAT AGC-3, agr III 5′-CTG TTG AAA AAG TCA ACT AAA AGC TC-3′, and agr IV 5′-CGA TAA TGC CGT AAT ACC CG-3′ [To determine the fourCC CG-3′ .μL volume of a reaction mixture composed of MgCl2 25 mM, 200 μM of the four dNTPs, 0.5 U of Taq DNA polymerase (Invitrogen), 10 pmol of each primer, and 1 μL of DNA solution in a thermocycler GeneAmp PCR system 2400. In this study S. aureus ATCC 25923 strain was used for the positive control.The PCR reactions were conducted in 50  S. aureus and the degree of susceptibility or resistance to each antibiotic evaluated, categorized into different degrees, thus: resistance (1), intermediate susceptibility (2), and susceptibility (3), according to the standards for each antibiotic established for S. aureus. The molecular variables were presence of mecA genes and the variants of the agr gene. A database was constructed with the variables of interest by using the Excel program.The unit of analysis was the bacterial isolate obtained from the nasal swab from which the microbiological and molecular characteristics were registered and were related with the sociodemographic characteristics of the carriers, like gender and academic semester. The microbiological variables were the presence of S. aureus was determined as percentage of time of permanence and gender. In the group colonized by S. aureus, an association analysis was performed among the different variables like resistance phenotype to different antibiotics, presence of mecA gene, and the agr genetic variant, bearing in mind the academic semester and the number of hours per day of practice: three hours for third-year students, five hours for fourth-year students, 8 hours for fifth-year students, and 12 hours for sixth-year students. Prevalence of the different agr gene variants was determined in MRSA and MSSA phenotypes.The presence ofχ2), and P value . The risk factor analysis of MRSA colonization was performed using SPSS statistical package .The findings were statistically analyzed using descriptive statistics, Chi-square test ( S. aureus. P < 0.05). The frequency of nasal carriage of S. aureus was significantly higher than on skin  and fifth-year students presented the highest frequency of S. aureus in the nose than on the skin   of the students who were in the different services at the hospital were colonized by= 0.094) .β-lactam antibiotics were distributed in a high number of students from all the academic grades, with a variation between 90 and 22% (Isolates with resistance to  and 22% . Isolate mecA gene was detected in the five isolates presenting simultaneous resistance to oxacillin-cefoxitin and in four isolates resistant only to cefoxitin (14.3%). The multidrug resistance phenotype was the distinctive characteristic in these MRSA isolates with simultaneous resistance to β-lactam, macrolide, aminoglycoside, and quinolone antibiotics  isolates. Thirty-five bacterial isolates (55.6%) were classified into agr group I, 31 (49.2%) strains were MSSA, and 4 (6.3%) strains were MRSA; the differences were statistically significant (P < 0.05).A total of 54 isolates were positive to agr group II; the mecA gene was detected in all isolates and agr group III was found only in 14 MSSA isolates (22.2%) (Five MRSA isolates (9.3%) were identified in (22.2%) . S. aureus strains isolated from students belonged to agr group I followed by agr group III (41 strains), and finally agr group II (9 strains) was distributed among the isolates of fourth-, fifth-, and sixth-year students. The agr groups I to III occurred in the major percentages  in fourth-year students (data not shown).The majority of S. aureus with 29.2% of prevalence in medical students in clinical rotation, and nasal carriage was a risk factor. The tendency is similar in Latin American countries with percentages between 50 and 20% [ S. aureus is reported at 25% [ S. aureus in Chinese, Malaysian, and Indian medical students is registered in 31% of the cases [The present study evidenced the presence of and 20% –13. In Ed at 25% –16. In Ahe cases .Although some studies report increased frequency of nasal carriers as medical students have greater exposure to the hospital environment during clinical rotations , 26, our S. aureus isolates resistant to penicillin, cephalexin, imipenem, erythromycin, chloramphenicol, clindamycin, tetracycline, gentamicin, trimethoprim-sulfamethoxazole, and ciprofloxacin, giving way to the presence of multidrug resistant isolates. These isolates can evolve in response to selective pressure exerted on microflora residing in patients, which are then passed on to students, or can be directly generated in the microflora of students.Our study determined a high frequency of mecA gene. In their study, Datta and colleagues demonstrated that cefoxitin induces the expression of the PBP2a protein encoded in the mecA gene; the cefoxitin disk diffusion test had the best diagnostic performance among the phenotypic methods for detection of MRSA [Similar results were obtained in studies conducted by Lee and colleagues ; all iso of MRSA .One of the factors that permit the presence of MRSA strains in asymptomatic carriers is due to antibiotic intake that strengthens overgrowth of organisms on the skin and on mucosa surface , 6. It hAlthough in Colombia it is reported that the majority of MRSA strains are not of nosocomial origin , an incrβ-lactam antibiotics and to multiple antibiotics  presented resistance to ibiotics  and, accl origin , 18.The presence of AH-MRSA strains in asymptomatic carriers is a potential risk of disseminating in the community; additionally, these strains are resistant to multidrug with few therapeutic alternatives. agr I. Nasal carriage of MRSA becomes an important reservoir and source of pathogen propagation among the personnel, the community, and the patient.However, we also found isolates with characteristics of community origin (AC-MRSA) in four MRSA isolates grouped inAs observed in  agr I and agr III, respectively, associating them with a molecular community origin.In addition, 49.2% and 22.2% of MSSA isolates were grouped in sek, seq, bsaB, lukF-PV, and lukS-PV genes, which encode the staphylococcal enterotoxins K and Q, bacteriocin, and Panton-Valentine leukocidin (PVL), respectively. Additionally, the clone typically contains a type I agr operon. The spread of MRSA could also be caused by the acquisition of SCCmec among asymptomatic carriers of S. aureus in the community [Several studies have found that the MRSA and MSSA circulating in Colombia have genetic similarities to clone USA300 , 30. Thi S. aureus are age, gender, hospitalizations, use of antibiotics, and some diseases and habitat [ S. aureus in medical students from the time they begin their clinical practice. Additionally, increased MRSA colonization was found in students as they spent more time in the hospital, as it is seen in fifth-year students showing the highest number of carriers.Although some of the risk factors for colonization by habitat , 12, amo