The South African family physician (FP) is an expert generalist who has a number of roles to strengthen the district health system. A research study on FPs in district hospitals has previously demonstrated an impact; however, more evidence on impact in primary health care (PHC) is needed. By serving as a consultant for the PHC team, the FP may improve access to care, capacitate team members, enhance comprehensiveness of care, and improve coordination and continuity of care. This report narrates the story of how one of the FPs at a rural district hospital recorded his experience of being a consultant to the PHC team and was able to self-audit the experience. A self-designed audit tool analysed 1000 patient consultations with the FP and enabled a reflection on the coronavirus disease 2019 (COVID-19)-related changes to the consultant role. There was a clear need for FPs to consult patients with complex multi-morbidity and multifaceted psychosocial aspects to their illness, in consultation with their team members. Patients were referred to them by medical officers, other specialists, family medicine registrars, allied healthcare professionals and nurse practitioners. The FP’s ability to strengthen the PHC service outside the district hospital may be enhanced by creating more FP posts at a subdistrict level to support high-quality, team-based primary care in line with the PHC policy directions. Their roles include clinical governance, capacity building, clinical training and championing of community-orientated primary care.4 This subdistrict consists of a 90-bed district hospital, which covers a geographic area of 2000 km2 through five fixed PHC facilities, seven satellite clinics and four mobile clinics. The subdistrict team provides the full scope of the DHS, in partnership with the specialist departments at George regional hospital. The team of doctors include a clinical manager, a FP, two family medicine registrars, nine medical officers and two community service medical officers. Whilst these doctors are based at the district hospital to provide generalist inpatient and outpatient care, they also support the nurse-led primary care services in the subdistrict through outreach. The PHC clinics also receive other visiting healthcare professionals, including a dietician, a physiotherapist, an occupational therapist and a mental health nurse.The Mossel Bay subdistrict forms part of the Garden Route District in the Western Cape province, South Africa and serves a population of 95 255 people.The first author started working in this subdistrict as a FP in September 2016. A key activity was to provide a consultant service to the PHC teams across various facilities. As the sole FP in the subdistrict, he had to ensure that his duties with regards to the six roles were shared between the district hospital and PHC facilities. In consultation with clinicians and managers, the FP reviewed his outreach service to PHC clinics as part of an effort to structure the working week better.The FP reviewed referred patients at the hospital’s outpatient department (OPD) on Mondays  and visited three PHC facilities on Tuesdays and Wednesdays . Patients were referred to the FP by the PHC team members through an internal booking system at each facility. These PHC team members included the subdistrict medical officers, family medicine registrars and allied health colleagues . The referral criteria were not fixed, as it was necessary to ensure that the team members felt comfortable referring patients for clinical input whenever they needed assistance. The FP encouraged learning conversations with PHC team members to decide whether to see patients at his clinic or whether it would be more appropriate to refer directly to the regional hospital specialist service to ensure a streamlined journey through the healthcare system. The FP also encouraged clinical nurse practitioners to discuss possible FP referrals directly with the medical officer on-site at the PHC facility, as often the medical officer would be able to confirm the need for FP referral or initiate a quick phone call with the FP to discuss the most appropriate care plan strategy for the patient. This triaging step was necessary to ensure the efficient use of the FP outreach service. Referrals to the FP from the regional hospital specialists were made either during their outreach visits to the Mossel Bay subdistrict or from the regional hospital OPDs .The FP conducted a prospective audit to describe the nature of patients referred to him from the PHC team in order to ensure an efficient consultation service. The FP developed a simple Microsoft Excel tool, which he piloted during March 2018, to capture data on several indicators, such as the referring primary care provider, clinical problem, any special investigations, involvement of other providers , interventions , and specialist code items prescribed . Examples of these specialist code pharmaceutical items included disease-modifying antirheumatic drugs, carbimazole, amiodarone, atorvastatin, pregabalin, doxazosin and losartan.The FP gathered data over 18 months (April 2018 – August 2019) and used the data on the first 12 months to review and improve his practice. During this period, there was an increase in the proportion of patients who were new referrals from 33% during the first 12 months to 40% during the final 6 months, which reflected an enhanced access to the FP of patients newly referred by the PHC team members . The FP From the findings shown in The FP service enabled learning conversations, feedback and capacity building with junior doctors, registrars and other PHC colleagues. The service also helped to strengthen the relationships between the PHC team and the specialist teams at the referral hospital, as well as the tertiary subspecialist services in Cape Town. Importantly, this FP outreach service and consultant clinics at PHC facilities improved the patient care experience by improving access to specialised care, coordinated by the FP, closer to their home and community.The FP also enabled informational continuity by maintaining an electronic database on his computer with key documents related to the patients. These included, for example, reports from the regional hospital, referral letters to specialists and results of special investigations. This central electronic repository was accessible to the senior family medicine registrar and the newly appointed FP, when the previous FP resigned in April 2020 to take on a new role. This ensured informational continuity of care during the transition period, as the senior family medicine registrar looked after the patients until the new FP started later in 2020.5In addition, as routine PHC services were de-escalated during the lockdown period from March to August 2020 of the coronavirus disease-2019 (COVID-19) pandemic, the FP outreach service to PHC was halted, and a list of patients for post-lockdown follow-up were kept. The referral hospital’s expectations of the FP also changed when their specialist outreach ceased during the COVID-19 pandemic. Consequently, the FP had to review patients previously seen during outreach visits from the regional hospital by their own specialists. The pandemic has resulted in the need for adjusting how the roles of the FP are implemented in practice.6 A larger scale analysis of the referral patterns to FP outreach services using more validated instruments with standardised diagnostic categories, such as the International Classification of Primary Care (ICPC),7 may provide useful information for policymakers and managers. A more nuanced understanding of the clinical skills and knowledge required by the newly qualified FP to manage patients referred by the PHC team will also assist postgraduate training programmes. Besides a model for registrars to ‘adopt’ a clinic and review patients weekly at the same PHC facility during their 4-year training, it would be good to also arrange for the registrar to join the FP during outreach visits to create opportunities for clinical governance  that will benefit both the registrar and clinic.More detailed evaluation of the reasons for referral to the FP and the threshold for referral by different members of the PHC team may be needed.9The phenomenon of a sole FP per subdistrict is not sustainable and limits the FP’s ability to strengthen the PHC service outside the district hospital, as the single FP needs to divide his or her contribution between the two. As part of the new human resources for health (HRH) strategy, there should be greater focus on creating more FP posts in the subdistricts to support high-quality, team-based PHC.This short report sheds some light on the role of the FP as a consultant within the PHC team. This self-audit showed that a FP based at a rural district hospital can support the PHC teams in the subdistrict by providing easier access to more specialised services for ambulatory patients at PHC facilities. This enabled better care coordination between generalists and specialists by ensuring appropriate referrals and continuity of care for patients whose health conditions required close monitoring over time. More rigorous research is needed to further evaluate the role of the FP as a consultant within the PHC team.


Multimedia data play an important role in our daily lives. The evolution of internet technologies means that multimedia data can easily participate amongst various users for specific purposes, in which multimedia data confidentiality and integrity have serious security issues. Chaos models play an important role in designing robust multimedia data cryptosystems. In this paper, a novel chaotic oscillator is presented. The oscillator has a particular property in which the chaotic dynamics are around pre-located manifolds. Various dynamics of the oscillator are studied. After analyzing the complex dynamics of the oscillator, it is applied to designing a new image cryptosystem, in which the results of the presented cryptosystem are tested from various viewpoints such as randomness, time encryption, correlation, plain image sensitivity, key-space, key sensitivity, histogram, entropy, resistance to classical types of attacks, and data loss analyses. The goal of the paper is proposing an applicable encryption method based on a novel chaotic oscillator with an attractor around a pre-located manifold. All the investigations confirm the reliability of using the presented cryptosystem for various IoT applications from image capture to use it. Developments in the Internet of Things (IoT), cloud computing, and fifth-generation network technologies make multimedia data easy to share with various users for specific purposes. In this context, the sharing of multimedia data suffers from serious security issues ,2,3,4. MChaotic oscillations are very complex dynamics, and there are many ambiguities about them. Many studies try to clarify the creation of chaotic dynamics . FormerlProposing chaotic systems with dynamics around a predefined manifold has been an exciting topic. In this paper, a novel chaotic oscillator is presented. The oscillator has a particular property in which the chaotic dynamics are around pre-located manifolds. Various dynamics of the oscillator are studied. The chaotic attractor and the predefined manifolds are discussed, and their relation with equilibrium points is investigated. Studying the bifurcation diagrams of the proposed system by different initiation methods shows the multistability of the system in some intervals of the bifurcation parameter. Lyapunov exponents of the oscillator are studied to show the interval of chaotic dynamics. In the multistability region, the exciting basin of attraction of various attractors is studied.Digital images are widely used for representing multimedia data in numerous applications. The complexity of chaotic time series makes them a proper choice for image encryption and secure communication ,18,19. NBased on the nonlinear features of the presented chaotic oscillator system, we present a novel image cryptosystem for IoT applications, in which the results of the presented cryptosystem are tested from various viewpoints. All the investigations show the reliability of the image cryptosystem for various IoT applications.Presenting a novel chaotic oscillator, in which the chaotic dynamics are around pre-located manifolds.Designing a novel image cryptosystem for IoT applications, of which the design is based on the nonlinear features of the presented chaotic oscillator system.The presented contributions of this work can be outlined as follows:Multimedia data, such as images, audio, and video are growing rapidly as an essential avenue for the representing, sharing, and storage of data in our daily lives. The evolution of internet technologies makes multimedia data can easily stored in cloud storage and shared amongst various users for specific goals. In this context, the confidentiality and integrity of multimedia data suffer from serious security issues. Therefore, we proposed a new framework for IoT applications to store and share digital images, in which image data confidentiality and integrity are achieved. The proposed framework is presented in The presented image cryptosystem can be utilized in different application fields, such as the medical sector, surveillance systems, personal data protection, etc. In the medical sector, the presented image cryptosystem can be utilized for the secure transmission of medical images from their origin to the intended stakeholders for analyzing, assessing, and treat patients. In surveillance systems, when the system detects any movement in the camera location, the video frames are captured and encrypted via the presented cryptosystem then sent the encrypted data to the intended stakeholders for analyzing and taking the appropriate decision. Moreover, the presented cryptosystem can be utilized for storing multimedia data to cloud storage then sharing/downloading it up to require.To maintain the integrity of the transmitted data via our presented cryptosystem, we utilized a hashing algorithm like SHA-256. The hashing algorithm is employed to get the hash code for the appended secret key with the cipher multimedia (secret key + cipher data), for making SHA-256 a keyed hash algorithm, then the generated hash code is sent with the cipher data. Upon the intended user downloaded the encrypted data and receiving the hash code, the hash value is computed for the received cipher data with the secret key, and investigate if the generated hash value is the same as the received hash code or not. If the two hash values are the same, then there are no changes in the transmitted cipher data, and the integrity of transmitted data has been achieved.In this paper, a chaotic oscillator with a unique feature is proposed as Equation .(1)x˙=zThe system presents a chaotic dynamic in To calculate the equilibrium points of the oscillator, all of its derivatives should be zeros simultaneously. So we can tell that the intersections of the three studied manifolds are the equilibria of the system. Equation  has two a. The diagram is plotted by the backward continuation method, and the first set of initial conditions are a, corresponding to the bifurcation diagram. One positive LE shows chaotic behaviors.To study different dynamics of the oscillator, the bifurcation diagram is presented in Multistability is one of the exciting features of dynamical systems. It means that two different sets of initial conditions result in two different attractors. The multistability of the oscillator is examined by plotting bifurcation diagrams using two different initiation methods, backward and constant initiation. After revealing the coexisting attractors, investigating the basin of attraction of each attractor is interesting. The protection of data represented by images can be achieved via image data protection techniques like image encryption, image data hiding, or mixing between them ,28. SpriThe presented image cryptosystem employs the benefits of our chaotic system to generate three pseudo-random sequences. The first two sequences are used to permute the plain image. Then the last sequence is utilized to substitute the permuted image for constructing the cipher image. The multimedia image cryptosystem is described in (1)PImg) to get the hash value (V).Perform the hash function SHA256 on the plain image ((2)V into 32 integer numbers  each of 8-bit, then obtain 3 decimal numbers from these integers as follows.Convert (3)Choose initial values for key parameters ( (4)a) for generating 3 sequences , in which PImg.Iterate the chaotic system  for H×W×(5)X to the values of Y as sequence W, then sort the values of W from the smallest to the largest as sequence S, and obtain the index S in W as PrVc.Add the values of (6)PImg) into a vector (PImgVc) and permute PImgVc using the produced vector PrVc as follows.Reshape the plain image ((7)K) by adapting the sequence Z into integers.Construct the key sequence ((8)PerImgVc and K to construct the cipher image CImg.Perform Bitwise-Xor operation on the permuted vector The utilized dataset of images is obtained from the Kodak database . It consThe effectiveness of any image cryptosystem depends essentially on performance (how fast we can encrypt an image on a defined computer) and resistance to various attacks: such as brute force, linear and differential cryptanalysis, statistical cryptanalysis, etc.). These two essential properties are discussed in the following subsections to show the effectiveness of the presented image cryptosystem.To demonstrate the effectiveness of the presented cryptosystem in terms of time encryption, For testing the randomness of the created sequence constructed the cipher image, we perform NIST SP 800-22 tests composed of fifteen tests. These tests are applied on a 2,000,000-bit of the constructed Cipher–Macaws image and its utilized key-stream. The outcomes are provided in A indicates the entire number of adjacent pixel pairs and To study the perception of an image, we employ the correlation coefficient  and UNCI (“Unified Average Changing Intensity”), which are represented as follows,a) to generate the chaotic sequences utilized in encryption and decryption procedures. By assuming the precision of computation for digital devices is Multifarious secret keys that can be utilized in brute force attacks are known as key-space. By the benchmark stated in , the keyIt is defined as the sensitivity of the decryption to the secret key. It is a necessary measure to guarantee the reliability of any cryptosystem. For evaluating the suggested image cryptosystem’s key sensitivity, the Cipher-Macaws image is deciphered many times using slight changes in the secret key as displayed in D denotes the image dimension and j. By considering the significant level To evaluate the pixel values’ distribution in the encrypted images, the histogram test is employed. A proper image cryptosystem has to guarantee the identical distribution for varied cipher images. To evaluate the bit distribution for each level of the pixel values of the encrypted image, the global entropy is employed as follows:a) have a slight modification, the outcome will change vastly. Furthermore, our encryption approach applies SHA256 to the plain image for updating the initial parameters, so that our cryptosystem not only depends on the secret key but also on the plain image. The cryptanalyst attempts to acquire useful information about the secret key utilizing all-white and all-black images, as they can disable the task of permutation/substitution procedures. The affiliated cipher images for the all-white and all-black images and their related histograms are provided in In general, the cryptanalysis of a cryptosystem assumes that cryptanalysts fully understand the structure of the cryptosystem and know all things about the encryption and decryption algorithms except the secret key utilized in encryption and decryption procedures. There are four kinds of attacks: ciphertext-only, chosen-ciphertext, chosen-plaintext, and known-plaintext . The choIt is significant that most of the data transmission networks are noisy channels. Once data are transmitted over noisy networks, it is probably distorted by noise or data loss attacks. So, a well-designed cryptosystem should withstand data loss and noise attacks. For investigating the proposed image cryptosystem for facing data loss and noise attacks, we defect the Cipher–Macaws image via performing a cutting block for data with various sizes or applying Salt and Pepper noise with variable densities. Then we decipher the defective image. The outcomes of noise and data loss attacks are displayed in a. Lyapunov exponents of the system were presented to determine the chaotic interval of the parameter. The multistability of the system was revealed by plotting bifurcation diagrams using different initiation methods. The basin of attraction of the attractors was studied. The proposed system was used in a multimedia image cryptosystem. The results were examined using different analyses such as randomness, correlation, plain image sensitivity, key sensitivity, histogram, entropy, and data damage analyses. The results of these tests confirm the reliability of using the presented cryptosystem for various IoT applications from image capture to use it.A novel chaotic flow was proposed in this paper in which its attractor was around some predefined manifolds. The bifurcation diagram of the system has exhibited a period-doubling route to chaos by modifying parameter


In this article, we review the biological and clinical implication of the Recruitment-Secretory Block (“R-SB”) phenomenon. The phenomenon refers to the reaction of the liver with regard to protein secretion in conditions of clinical stimulation. Our basic knowledge of the process is due to the experimental work in animal models. Under basal conditions, the protein synthesis is mainly carried out by periportal (zone 1) hepatocytes that are considered the “professional” synthesizing protein cells. Under stimulation, midlobular and centrolobular (zones 2 and 3) hepatocytes, are progressively recruited according to lobular gradients and contribute to the increase of synthesis and secretion. The block of secretion, operated by exogenous agents, causes intracellular retention of all secretory proteins. The Pi MZ phenotype of Alpha-1-antitrypsin deficiency (AATD) has turned out to be the key for in vivo studies of the reaction of the liver, as synthesis and block of secretion are concomitant. Indeed, the M fraction of AAT is stimulated for synthesis and regularly exported while the Z fraction is mostly retained within the cell. For that reason, the phenomenon has been designated “Recruitment-Secretory Block” (“R-SB”). The “R-SB” phenomenon explains why: (a) the MZ individuals can correct the serum deficiency; (b) the resulting immonohistochemical and electron microscopic (EM) patterns are very peculiar and specific for the diagnosis of the Z mutation in tissue sections in the absence of genotyping; (c) the term carrier is no longer applicable for the heterozygous condition as all Pi MZ individuals undergo storage and the storage predisposes to liver damage. The storage represents the true elementary lesion and consequently reflects the phenotype-genotype correlation; (d) the site and function of the extrahepatic AAT and the relationship between intra and extracellular AAT; (e) last but not least, the concept of Endoplasmic Reticulum Storage Disease (ERSD) and of a new disease, hereditary hypofibrinogenemia with hepatic storage (HHHS). In the light of the emerging phenomenon, described in vitro, namely that M and Z AAT can form heteropolymers within hepatocytes as well as in circulation, we have reviewed the whole clinical and experimental material collected during forty years, in order to evaluate to what extent the polymerization phenomenon occurs in vivo. The paper summarizes similarities and differences between AAT and Fibrinogen as well as between the related diseases, AATD and HHHS. Indeed, fibrinogen gamma chain mutations undergo an aggregation process within the RER of hepatocytes similar to AATD. In addition, this work has clarified the intriguing phenomenon underlying a new syndrome, hereditary hypofibrinogenemia and hypo-APO-B-lipoproteinemia with hepatic storage of fibrinogen and APO-B lipoproteins. It is hoped that these studies could contribute to future research and select strategies aimed to simultaneously correct the hepatocytic storage, thus preventing the liver damage and the plasma deficiency of the two proteins. The liver synthesizes the vast majority of secretory plasma proteins and represents the only source of circulating alpha-1-antitrypsin (AAT) and fibrinogen . Li. Li17]. In Groups 1 and 2, all hepatocytes (up to 100%) could be positive a. The poIn ZZ patients from groups 2 and 4, the positivity was mainly restricted to zone 1  hepatocyte in the form of PAD positive globules  filling In Pi MZ patients, the polyclonal antibody gave a stronger positivity than the monoclonal and apparently involved more hepatocytes a–d. The In an attempt to objectivize the different staining intensities between the two antibodies, we could only have a recourse to a graphic stratagem by working out with In Groups 1, 2 and 4 biopsies, under the EM, AAT appeared in the form of fluffy amorphous material within the lumen of dilated cisternae of the RER a. In perIn Pi MZ livers the intralumenal AAT could present a yet undescribed feature made up of fibrils, and tangles of filaments .Similar features had been described in an experimental work at very high EM magnification in AAT inclusion bodies extracted from a Pi ZZ liver  and moreThe AAT containing cisternae were distributed in the entire cytoplasm in type I positive hepatocytes a, while The “R-SB” phenomenon has been described in 1983 in a PhD thesis  and publThe identification of the phenomenon has been made possible by comparing the serum and morphological findings in Pi MZ phenotype with the amount and anatomical distribution of the RER in the normal human liver , as scheAs type II positivity occurs in all Pi MZ cases with normal or elevated serum AAT levels, it identifies the newly recruited cells for synthesis during acute phase stimuli, whilst type I positivity is commonly observed in periportal hepatocytes that are predisposed to chronic engulfment as they synthesize the protein continuously. For that reason, immunostaining and EM patterns have been considered as expression of simultaneous recruitment of new hepatocytes for synthesis of both M and Z AAT and of secretory block of the Z protein. The phenomenon has been labelled as “Recruitment-Secretory Block” (“R-SB”) and type II positivity proposed as its hallmark .In other words, the R-SB phenomenon turns out to reveal the extent of engagement in the synthesis and the extent of derangement of the liver in the secretion of AAT.The AAT immunostaining pattern in PI MZ individuals reflects not only the amount and the distribution of the RER in the normal human liver according to Ma and Biempica a, but alThe “R-SB” phenomenon has definitely clarified the difference between acquired and congenital defects of protein secretion. In the former, exemplified by the turpentine/colchicine model, the block is due to an exogenous agent and causes a collective retention of secretory proteins, whilst in Pi MZ individuals, the secretory block is intrinsic in the mutant Z protein and results in a selective retention b.The described “R-SB” phenomenon is in agreement with the concept that the plasma levels in Pi MZ heterozygotes result from independent secretion of the two variants (24).However, in Pi MZ individuals, the immunostaining of liver sections with a polyclonal anti-AAT antibody, which recognizes all AAT variants, has shown a higher amount of retained protein as compared to the monoclonal anti-Z AAT antibody, which recognizes exclusively the Z fraction.This observation per se would suggest that the immunoreactive inclusions could contain not only Z but also M AAT.Interestingly enough, the positive reaction obtained only in freshly frozen Pi MM livers, appeared as a full cytoplasmic staining, indicating that the protein was located within the entire secretory pathway . This paThe authenticity of the immunomorphological findings in Pi MZ livers, has been confirmed by comparing consecutive sections alternatively stained. Whether these findings allow the interpretation of a colocalization of Z and M AAT in the form of heteropolymers is highly suggestive in view of recognized phenomenon of AAT heteropolymerizations , recentlIn that respect, it is worth mentioning the positive immunoreaction we observed in endothelial cells of portal tract vessels with the monoclonal ATZ 11 antibody that, according to Janciauskiene et al., detects circulating and endothelial cell polymers of Z and wild-type AAT . SecretiThe ability to form heteropolymers within cells most likely reflects the capacity of each protein to form an unstable intermediate conformer (M*) which acts as a nucleus for heteropolymer formation ,28. As nWe believe that our immunohistochemical findings represent the in vivo macroscopic counterpart of the heteropolimerization of AAT mutants observed in cell models mimicking heterozygosity. In other words, from the immunohistochemical results, it would seem that the polyclonal AAT antibody in Pi MZ individuals is staining the co-localized M and Z component.Laffranchi et al. were able to calculate that M AAT comprises around 6% of the polymer subunits in the MZ liver sample . Our metTaken all together, the available data allow to forward the following hypothesis on M-Z aggregation and Z (vs M) rescue, expressed into two cartoons.Cartoon A  shows thStudies on AAT polymer formation have been performed on polymers extracted from the liver tissue of a MZ AAT heterozygote by using a conformationally developed antibody with selectivity for M AAT with respect to Z AAT. The rationale of that in vitro model is comparable to the in vivo “R-SB” phenomenon in Pi MZ phenotype. Moreover, the results appear to be in congruence. The final proof about the equivalence would come from prospective studies on Pi MZ livers, by using anti-Z and anti-M monoclonal antibodies in consecutive sections or in double immunostaining on the same section.The liver is the only source of fibrinogen in humans. Here we review, in a telegraphic way, the biosynthesis of fibrinogen in order to understand the mechanism of aggregation in case of mutations.The circulating fibrinogen is a hexamer made up of two sets of symmetrical trimers, each formed by A-alpha, B-beta and gamma chains respectively encoded by FGA, FGB and FGG genes. The hexamer molecule contains a central E region and two lateral regions, corresponding to the globular D domain. The D domain is crucial for D:D formation. Indeed, all eight mutations so far described in the globular domain of the gamma chain ,33,34 inThe assembly of the two trimers takes place in the ER, through a stepwise process, with an initial formation of dimers and a subsequent addition of a third chain followed by the fast integration of the two trimers. Abnormal gamma monomers cause intracellular aggregation and leave exposed hydrophobic patches that become available for undue binding to other hydrophobic molecules, such as APO-B-lipoproteins . After mThe secretion of fibrinogen under acute phase stimuli has been studied extensively in experimental animal models by the turpentine/colchicine model. Subcutaneous injection of turpentine induces an inflammatory reaction. The liver responds by a progressive recruitment of hepatocytes from zone 1 to zone 3 for the synthesis of acute phase proteins. Interestingly, when liver tissue sections are stained in such conditions, hepatocytes show a diffuse cytoplasmic staining as the immunoreaction is depicting the proteins moving along the entire synthetic pathway . This staining pattern is analogous to that observed in frozen sections from Pi MM individuals as shown in Colchicine, injected intraperitoneally at intervals, depolymerizes hepatocytic microtubules and prevents the migration of SV towards the cell membrane, thus blocking the last step of secretion. That results in the retention of not only fibrinogen but also of all secretory proteins  b.In patients affected by HHHS, the mutant fibrinogen is retained within the RER and only a small amount is exported into the circulation. In our original Fibrinogen Brescia mutation, the patient as well as family members, had shown constantly low plasma levels over a 15year follow-up period . In the HHHS is an extremely rare condition as compared to AATD and occurs only in the heterozygous state. The homozygous condition is believed to be incompatible with life . This baMoreover, no single HHHS patient has so far developed HCC or systemic diseases that, in heterozygous AATD patients, are associated with serum elevation of AAT due to the “R-SB” phenomenon.Heterozygous HHHS seems to behave like the homozygous Pi ZZ AATD. In both these conditions, the circulating levels of AAT and fibrinogen are very low. Only 10-15% of the Z AAT and less than 10% of fibrinogen are exported but apparently no mutant gamma chains are found in circulation ,39. The On immunostaining, HHHS and Pi ZZ patients show a similar pattern especially in the cirrhotic stage. Hepatocytes show mainly type I positivity, but type II can be observed in some areas of the nodules .Type II positivity depicts midlobular and centrolobular hepatocytes that constitutively contain less amounts of RER localized only at the cell periphery. In analogy to AATD, the retention of fibrinogen in that subcellular location indicates that the RER is the major site for the storage of fibrinogen and that the storage starts in the very early stage of synthesis in freshly recruited hepatocytes for protein synthesis.Under the EM, the mutant fibrinogen in the RER shows a highly specialized organoid appearance resulting from closely packaged curved tubular structures resembling finger print or elongated fibers suggesting fiber glass. The fiber glass inclusions are better visualized in immunostained preparations that highlight the acicular cristal-like configuration .The association of hypofibrinogenemia and hypo-APO-B-lipoproteinemia has been described in fibrinogen gamma chain mutations . The molAll fibrinogen mutations in HHHS are located at the globular gamma domain of the gamma chain involved in the “end-to-end” interaction thus impairing the D-dimer formation. Therefore, each monomeric gamma chain is left with an abnormal exposure of hydrophobic patches that can trigger an irregular recruitment of the hydrophobic molecules APO-B and lipids, causing their intracellular retention and impairment of export .The association between HHHS and hypo-APO-B-lipoproteinemia represents a new syndrome. Interestingly, a physiological link has been demonstrated between the two proteins either in basal or fibrinogen overexpression . APO-B rThe simultaneous retention of abnormal fibrinogen and normal lipoprotein molecules appear to share some analogy with the divergent behavior of M and Z AAT fraction as reflected into the “R-SB” phenomenon, and at the same time with the recent observations showing that about 6% of the normal M AAT can make heteropolymers with the Z AAT in the RER  and thatPresently no treatments are available for HHHS. Carbamazepine and ursodeoxycholic acid have been used empirically ,47. ShorConsidering the pathogenesis of the newly described syndrome, one would predict that APO-B-deficiency could be managed by using exogenous small molecules replacing APO-B in binding hydrophobic patches of the abnormal gamma monomers.In analogy with AATD however a logical rationale would be the exploitation of the formation of intracellular heteropolymers between the two stored proteins and their export in order to obtain serum concentration elevation of both proteins.Until specific treatment will be available, it could be a challenge to treat HHHS and APO-B by using the same protocol treatment that has been shown to be effective in congenital APO-B deficiency.Pi Z transgenic mice have been used as an animal model for human AATD ,49. All We have reported a morphological and genetic study on a large number of Pi Z transgenic mice , and in The rationale of the study was based upon the following statements: (i) Pi Z mice liver synthesizes both normal mouse AAT and Pi Z human AAT; (ii) the normal mouse AAT is regularly exported like the M AAT in humans; (iii) 85% of the Z AAT is retained within the RER of hepatocytes; (iv) there is no immunohistochemical cross-reaction between human and mouse anti-AAT antibodies; (v) both monoclonal and polyclonal antibodies are staining the human Z AAT but not the mouse AAT.In mice with HCC or other malignancies, the AAT staining pattern of the normal parenchyma involved large areas of the lobules either in a confluent or in a streaming-like fashion (pattern A) a. HHC arThis intriguing phenomenon has been previously discussed . In miceUnfortunately, this study has been designed retrospectively, therefore we could not perform serum concentration determination of either protein. However, in the light of the “R-SB” phenomenon, it is reasonable to forward the interpretation of pattern A as an expression of acute phase reaction and of pattern B as an expression of resting or basal conditions.As the Pi Z mice do not carry the human M allele and polyclonal anti AAT antibody does not cross-react with the mouse AAT, the transgenic mice model is not suitable for polymer or allo- or hetero-polymer formation studies.The lack of serological data in our study represents a limitation for comparing Pi Z mice and homozygous or heterozygous human AATD. According to Carlson’s data , howeverIn this article, we have shown how experimental animal models have contributed to the understanding of the morphodynamics of the synthesis and block of secretory proteins in liver tissue.Like in humans, the protein synthesis starts in zone 1 where professionally protein synthesizing hepatocytes are located. Under acute phase stimuli, hepatocytes of zones 2 and 3 are recruited for additional synthesis and rapid export that leads to increased plasma levels. Each hepatocyte is synthesizing the vast majority of acute phase reactants.The secretory block brought about by colchicine, after turpentine stimulation, results in retention of all proteins. The phenomenon is called collective retention of secretory proteins. The block affects, first the SV and subsequently backwards the Golgi apparatus, SER and RER. The proteins stagnate in the channels of the secretory pathway and give rise to inclusions visualized in light and EM.The animal model applies to the acquired storage of secretory proteins in human liver after excess alcohol intake or other cytotoxic agents that cause microtubule damage and dysfunction.However, the model does not apply to the congenital storage of mutant secretory proteins in AATD or HHHS.To study in the same time stimulation and secretory block of mutant proteins we have selected the Pi MZ phenotype of AATD because of the unique intrinsic property of simultaneous stimulation and block of secretion. The total pool of AAT synthesis in Pi MZ hepatocytes is made up by 50% of M protein and 50% of Z protein. Under conditions of clinical stimulation, both fractions undergo an increased synthesis. The M fraction is regularly exported and its serum level increases many folds. The Z fraction is retained within liver cells and gives rise to an increased amount of storage. The resulting peculiar immunostaining and EM patterns have been considered as expression of simultaneous recruitment of liver cells for synthesis and block of secretion of the mutant protein. For that reason, when originally described, the phenomenon has been called “Recruitment-Secretory Block” and has been considered sufficiently satisfactorily to explain the different morphological and serological behavior of Pi ZZ and Pi MZ individuals in response to acute phase stimuli.The discovery of the intriguing phenomenon of M AAT and Z AAT intrahepatic heteropolymer formation, has urged us to review, retrospectively, the morphology of the study material that had led to the description of the “R-SB” phenomenon.By running from the emerging molecular findings backwards to a critical retrospective evaluation of the published material, we found an indirect evidence that M and Z polymers can also form in vivo. Indeed, the monoclonal Z AAT antibody in Pi MZ individuals appears to stain less amount of aggregated AAT than the polyclonal antibody. The latter depicts all variants of the protein including the M. In the light of the unequivocal demonstration of the co-localization of Z and M AAT in heteropolymers , it is rAs expected, under the “R-SB” phenomenon, the M AAT as part of the heteropolymers, becomes detectable due to the increase in its intracellular concentration.Secretion of Z polymers in cell models of disease  and circGiven the potential relevance of our observations, in view also of the in vitro study results, future studies should be carried out in liver tissue specimens to confirm the validity of our interpretation that quantitative evaluation could reflect qualitative meanings.About 85% of the Z protein is retained and only some 15% is exported in circulation. Laffranchi et al. have calculated that in Pi MZ livers, M AAT comprises around 6% of the polymers subunits. That raises an important question about the percentage of M subunits rescued under the “R-SB” phenomenon. Considering that the “R-SB” phenomenon induces an increasing synthesis of both M and Z proteins, one may predict an increasing amount of M-Z polymers both within the hepatocytes and in circulation.HHHS is an extremely rare new disease, therefore very little is known about its natural history. We know that less than 10% of fibrinogen is exported and that, in contrast with AATD, the mutant gamma chains appear to be completely retained within the cell and never found in circulation. Few available data suggest that HHHS heterozygosity behaves in a completely different way than the heterozygous AATD, but no studies have been performed so far to explore how the mutant fibrinogens respond to acute phase stimuli.With regard to the ongoing research effort on the treatment of ERSD, a further relevant observation in our studies refers to the ultrastructural appearance of the ZAAT. Since the first ultrastructural observation by Sharp et al., the ZAAT has been always described as amorphous fluffy material within the RER . In addiThese EM features are in keeping with the loop sheet mechanism of polymerization . PolyacrThe corpuscular forms of Z AAT, mainly observed in the course of the “R-SB” phenomenon in Pi MZ livers, suggest that the formation and aggregation of Z polymers are a very early event during the elongation of the polypeptide chain and their discharge into the lumen of the RER.The same holds true for mutant fibrinogens that start aggregating during translation. The amplified acrobatic organoid fashion of fibrinogen probably reflects the complexity of the stepwise interaction and integration of the various monomers and dimers of the three chains.The finger print and fiber glass appearance of the aggregated fibrinogen under the EM are reminding of the clot formation. Fibrinogen is converted into insoluble fibrin through a stepwise process including the assembly of single fibrin monomers into protofibrils that, in turn, aggregate into fibrin, thus yielding the stable fibrin meshwork. In the intermediate stage of the process, the fibrils display a similar metameric array as the aggregated intracellular fibrinogen.In other words, normal secretory proteins that are soluble in the ER milieu and transparent under the EM, due to mutations, become visible under the EM after acquiring an abnormal conformation that renders them insoluble.The Recruitment-Secretory Block phenomenon occurring in ERSD has contributed to visualize the early stage of the aggregation process of both Z AAT and abnormal fibrinogen gamma chains. The peculiar EM appearance of the aggregated proteins represent a snapshot of the crazy paving that, together with the 3-D modeling  could ad


The ability of mercury to deposit throughout the body and alter a wide range of molecular and cellular pathways results in a polymorphic and complex clinical phenotype with over 250 possible symptoms. However, some of them are recurrently cited as evoking chronic mercury poisoning. In this light, dentists users of dental amalgams are chronically exposed to mercury so that in-depth epidemiological investigations and adapted statistical methods are required to highlight adverse effects of this exposure.In order to study the health impact of the occupational mercury exposure in a population of liberal dentists practicing in two Moroccan regions, a list of eighteen subjective symptoms commonly associated with micro-hydrargyrism was drawn up. Then, seven statisctical models adapted to count data were fitted. Finally, three methods were used to compare their relative performance in order to choose the most appropriate one.The adopted logical path, from the response variable selection till models' comparison, led us to lean towards quasi-Poisson regression as the best way to predict the number of symptoms declared by dentists according to mercury exposure.Interpretation of the selected model allowed us to conclude that the reduction of dental amalgam use allows the reduction of subjective symptoms related to mercury exposure. Mercury is the only metal found in a liquid state under ambient conditions. Owing to its very low vapor pressure, it readily vaporizes at room temperature. Under this state, it is easily absorbed through the lungs and distributed through the body via the bloodstream. Consequently, this metal is considered as a potent toxic biohazard at room temperatures . MoreoveIn dentistry, elemental mercury is used in dental amalgams. Despite periodic safety concerns and the availability of alternative dental restorative materials, silver amalgam still remains one of the most cost- effective and durable material chosen by many dentists around the world . As handIn this context, an exhaustive cross-sectional survey was carried out to evaluate mercury exposure among liberal dentists in two Moroccan regions . DescripIn the present work, to investigate the health impact of this exposure within the studied population, a non-exhaustive list of eighteen symptoms that are commonly associated with chronic mercury poisoning was drawn up and integrated into the questionnaire distributed to participants –10. ThisStudy design and ethical considerations: The current study uses a database obtained from a previous exhaustive cross-sectional survey conducted to evaluate the health impact of mercury exposure among a population of liberal dentists in two regions of central Morocco  was then created to code the total number of symptoms self-reported by each participant. Tsym is the random component of the model.The number of amalgams weekly handled by each dentist  to evaluate the current occupational exposure to mercury;The number of amalgam fillings in the participant mouth  to evaluate the nonoccupational exposure to mercury. The other exposure origins like fish consumption, vaccines or smoking were judged not relevant in our previous study ;Four socio-demographic variables were also considered: gender, exercise area  coded as Area, seniority (number of years in the active practice) and age.Six explanatory variables were initially selected:Modeling count data; general remarks: Conditions for Ordinary Least Square models (OLS) can rarely be assumed when outcomes are expressed as counts. Making awkwardly such a choice will lead to biased parameters as well as standard errors and confidence interval estimates of the wrong size  and Bayesian Information Criterion (BIC) statistics;Comparison of the five-fold cross validation mean squared errors (CV.MSE);Graphical comparison using half-normal plots with a simulated envelope for residuals.Statistical software used for analyses: The data analysis was carried out with the software R version 3.6.1  and the variance (5.71) of the response variable suggests that Poisson distribution would not be suitable. To confirm this, we compared our counts distribution with a randomly generated theoretical Poisson distribution with a parameter equal to the observed mean  = 31.1 for both of them). Seniority was preferred to be kept in the model because it better reflects the time of occupational exposure rather than the simple age.glmulti . In this context, after pre-selecting explanatory variables, these two issues were the first to face after preliminary data exploration. The first step was therefore to select the most relevant variables and pairewise interactions to use in a basic Poisson model. As the fitting of this latter was bad, model's diagnostics were performed to recognize why and where the fit was poor. After deleting an observation with evident outlier and concluded that the model was over-dispersed and zero-inflated, six models were run to deal with these problems. In order to determine the most suitable of them, three different methods were used for their comparison.The adopted logical path, from the response variable selection till the different models comparison, led us to choose QP model as the best way to predict the number of symptoms declared by dentists in correlation with mercury exposure. Its interpretation allowed us to conclude that the reduction or cessation of dental amalgam use helps to reduce significantly the number of subjective symptoms related to the occupational mercury exposure. Moreover, the duration and the presence of another source of exposure contributes to increasing the number of symptoms expressed by dentists.The present study, despite methodological precautions taken while modeling and the interest of the obtained results, suffers from two main problems. Indeed, as our dependent variable was based only on the self-reported symptoms from a pre-established list, a classification bias might be generated by the suggestibility of some participants or, oppositely, by their misinterpretation of long-lasting symptoms. In the systematic component of the fitted model, exposure was estimated only by the number of amalgams weekly handled which reflects globally, without great precision, the current exposure. In this context and in the light of the encouraging obtained results, another study with an objective determination of symptoms  and a more precise evaluation of the current and cumulative (body burden) exposure is highly desirable.


The serotonin signaling pathway has been well understood in the neurons for decades , 2. DuriICB therapy is the subject of growing interest as oncology is becoming an increasingly immunological field , 7. Anti  was positively correlated with immune suppression . A knockMAO-A regulation of T cell activity was further investigated through the administration of MAOIs as a means of artificially inhibiting MAO-A activity and the breakdown of serotonin. In a mouse B16-OVA melanoma model, Wang et al. demonstrated dramatic tumor-suppressive effects of the MAOI antidepressants phenelzine, clorgyline, and moclobemide, which represented three classes of MAOIs, varying in the reversibility of the drug’s effects (reversible vs irreversible) and the selectivity for the serotonin-degrading MAO-A isoform over MAO-B (selective vs nonselective) . There wThe efficacy of phenelzine as an ICB therapy was also demonstrated to inhibit immunosuppression through TAM polarization . This prWhile MAOIs were the primary class of antidepressants for the majority of the second half of the 20th century, they have fallen largely out of fashion due to the adverse side effects associated with their administration and the rise of alternative drugs . MAOIs hDespite these potential negatives, the utilization of MAOIs still shows significant promise, and the process should be optimized to increase drug efficacy and patient wellbeing. One potential source of side-effect remediation is through the development of nanoformulated MAOIs that can be targeted for delivery to the tumor. This would prevent many of the systemic side-effects of the drug and restrict its effects only to TIIs demonstrated to experience immunosuppression as a result of MAO-A activity . LiposomThe discovery of MAO-A as an immune checkpoint offers an exciting new pathway that can be explored for the development of novel therapies repurposing drugs developed for the regulation of neuronal serotonin signaling , 14. ResWhile the potential associated with the use of a multifaceted ICB therapy such as MAOIs is impressive, it is important to consider the adverse side-effects that can greatly threaten the comfort and safety of the patient. However, there are several avenues of research that may help mitigate these side effects while successfully downregulating immunosuppressive pathways. As discussed, the use of liposomal drug delivery systems has shown significant promise in increasing the specificity of small-molecule drug delivery, and the development of a liposomal MAOI could provide the necessary specificity to avoid the adverse side effects currently associated with MAOI treatment , 18.Additionally, the serotonergic pathway is complex, and, while the direct administration of serotonin would likely have limited lasting effects, other important protein targets in the serotonin production, reception, transport, and degradation pathway could potentially lead to more effective or less adverse ICB , 27. Becvia autologous serotonin-MAPK signaling, which is nonredundant to other immune checkpoint regulatory pathways, suggesting that they may have widespread applications as a combination therapy that increases the efficacy of classical ICBs. MAOIs’ inhibition of alternative macrophage polarization also plays a major role in increasing the host antitumor response .L.Y. in an inventor on patents related to this topic filed by UCLA.The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Aim of the study was to see how a definition of the flexible flat foot (FFF) influences the results of gait evaluation in a group of 49 children with clinically established FFF. Objective gait analysis was performed using VICON system with Kistler force platforms. The gait parameters were compared between healthy feet and FFF using two classifications: in static and dynamic conditions. In static condition, the ink footprints with Clarke’s graphics were used for classification, and in dynamic condition, the Arch Index from Emed pedobarograph while walking was used for classification. When the type of the foot was based on Clarke’s graphics, no statistically significant differences were found. When the division was done according to the Arch Index, statistically significant differences between flat feet and normal feet groups were found for normalized gait speed, normalized cadence, pelvic rotation, ankle range of motion in sagittal plane, range of motion of foot progression, and two parameters of a vertical component of the ground reaction force: FZ2 (middle of stance phase) and FZ3 (push-off). Some statically flat feet function well during walking due to dynamic correction mechanisms. A plano-valgus foot is the most common posture deformity among children ,2,3. DesNowadays, the plano-valgus foot kinematics assessment methods are gaining importance because they can be used not only for the evaluation of the flat foot posture but also for the assessment of the flat foot performance during walking. Additionally, the influence of the flat foot on the overall gait pattern can be assessed. They seem to be more objective and their results more compatible among researchers. Twomey et al.  found inThe human musculoskeletal system is a biomechanical chain; therefore, a pertinent question is whether the plano-valgus foot deformity affects not only foot joints but also upper joints of the lower extremities, pelvis. and lower back . Duval eTaking into consideration the wide range of clinical diagnostic tools and findings concerning the influence of the flat foot on gait pattern, the aim of this study was to see how a definition of the flexible flat foot (FFF) influences gait parameters in children five to nine years of age and if the choice of a diagnostic method of FFF used in the study (in static vs. dynamic conditions) affects its results. The definitions of FFF used in practice differ from each other, which means that the applied method of foot classification influences the assessment of the patient’s gait stereotype and the resulting therapeutic management. The importance of the research undertaken is due to the potentially negative impact of foot deformation on the quality of life in adulthood.Forty-nine children (37 boys and 12 girls) were recruited to the study. Recruitment was carried out in the period of two years during the clinical examination at The Children’s Memorial Health Institute in Warsaw, Dept. Rehabilitation, at the Outpatient Clinic. All children fulfilling the criteria were invited to participate. The inclusion criteria were as follows: age from 5 to 9 years and flexible flat foot, clinically established. The exclusion criteria were: rigid flat foot, secondary flat foot caused by the damaged central nervous system (CNS), neuromuscular diseases, lower-limb injury, or surgical intervention in the lower legs in the past. The demographic characteristic of the group is presented in Informed consent was obtained from the parents of all children taking part in the study before their enrolment.Preliminary diagnose of the flexible flat foot was based on a clinical examination conducted independently by an experienced physician and physiotherapist. A foot was defined as flat when, during the examination while standing, the MLA was collapsed, and/or the medial side of the foot was bulging because of the talus head protruding just under the medial malleolus. The heel valgus angle was measured with a goniometer during standing on both feet. It was measured three times, and then, an averaged result was calculated. Flexible flat foot was identified when the MLA rebuilt in non-weight-bearing position and while tiptoe standing.After the preliminary examination, ink footprints from the Harris and Beath pedograph were obtained, and they were further compared with Clarke’s footprinting graphics. A foot was diagnosed as flat if the ink footprint from the Harris and Beath pedograph matched Clarke’s footprinting graphics types between 7 and 10. The matching of footprints was performed independently by two experienced examiners, and no discrepancy between their results occurred. The complete description of the examination methodology on the Harris and Beath pedograph is included in the previous study .Next, plantar loads during gait were evaluated A. PlantaData from three plantar loads of left and three plantar loads of right foot of each child were averaged and taken for further analysis. Geometric measures of the feet  were calculated by Novel software. The Arch Index was calculated based on the definition introduced by Cavanagh and Rodgers. The value of Arch Index equal to 0.27 was taken as cut-off value between normal and flat foot.Objective gait analysis was performed using a 12 camera VICON MX System B. The PlStatistical analysis of the data comprised a chi-square test to check the variables’ distribution, the Wilcoxon signed-rank test for matched pairs to find differences between parameters of left and right leg, and the Mann–Whitney U test to compare lower extremities ROM and kinematic and spatio-temporal parameters of the healthy and flat feet. The statistically significant level was set as 0.05.Two different comparisons were performed in the analysis. In the first one, the data were divided into two groups based on Clarke’s classification: the first group consisted of flat feet and the second of normal feet. In the second one, the division to flat and normal feet was based on the Arch Index from dynamic walking on emed platform.The comparisons of the parameters between left and right leg, done with Wilcoxon signed-rank test, showed no differences; thus, the data from left and right legs were pooled together.When the type of the foot was based on Clarke’s footprinting graphics, no statistically significant differences were found between flat feet and normal feet groups in spatio-temporal, kinematic, or ground reaction force parameters.In the second case, when the division was done according to the Arch Index from the pedobarography, the following parameters were statistically significantly different between flat feet and normal feet groups: normalized gait speed , normaliThe summary statistics of all analysed parameters is given in It is commonly believed that flat foot affects walking pattern ,27. AlthThe aim of this study was to investigate how, if at all, a FFF influences gait parameters in children and if a choice of a diagnostic method used to identify FFF affects the results of the gait pattern assessment. We examined spatio-temporal, kinematic, and kinetic parameters of the flat feet and healthy feet in a group of children, using two different classification methods. The main result is the finding that a diagnostic method according to which the flat foot is established has an important impact on the results. The statistically significant differences of gait parameters between healthy and flat feet were found only when the classification was based on the Arch Index in dynamic condition. We decided to use two classification methods because defects in foot posture in static conditions are not always seen in dynamic conditions: in fact, flat foot posture is not always accompanied by the impaired function ,18,30,31Examining the spatio-temporal parameters, we found, as observed also by Carravaggi et al., Lin et al., and Hösl et al. ,14,18 a From other researchers’ studies, it is already known that speed is a factor that significantly affects both kinematic and kinetic parameters, such as joint ROM, joints moments, the ground reaction forces . StansfiRegarding the kinematic parameters in this study, a statistically significant decrease in ankle ROM in sagittal plane was observed in children with FFF in comparison to healthy feet. The decrease in the ankle range of motion in a sagittal plane means a weaker push-off during gait and relates to a lower FZ3—a parameter of the vertical component (second maximum) of the ground reaction force during this phase of gait. Similar results were obtained by other researchers ,31. HöslRecently more proofs were found to support the hypothesis that morphology of the flat foot is not always accompanied by its abnormal function . TherefoThe main limitation of the present study is the relatively low number of patients and the imbalance between female and male participants. This resulted from the fact that the patients were recruited from the outpatient clinic, and all patients who fulfilled the criteria were invited to participate.In conclusion, the diagnosis of the flat foot based on the evaluation in the static condition and during the clinical assessment seems not be sufficient for decision making about the treatment of pediatric patients with flexible flat foot. One of the main findings from our study is that the gait pattern pathology seen in the gait parameters can depend on the classification method within the same group of patients with clinical problem.


The human auditory system is exceptional at comprehending an individual speaker even in complex acoustic environments. Because the inner ear, or cochlea, possesses an active mechanism that can be controlled by subsequent neural processing centers through descending nerve fibers, it may already contribute to speech processing. The cochlear activity can be assessed by recording otoacoustic emissions (OAEs), but employing these emissions to assess speech processing in the cochlea is obstructed by the complexity of natural speech. Here, we develop a novel methodology to measure OAEs that are related to the time-varying harmonic structure of speech [speech-distortion-product OAEs (DPOAEs)]. We then employ the method to investigate the effect of selective attention on the speech-DPOAEs. We provide tentative evidence that the speech-DPOAEs are larger when the corresponding speech signal is attended than when it is ignored. Our development of speech-DPOAEs opens up a path to further investigations of the contribution of the cochlea to the processing of complex real-world signals. Real-world environments, such as a loud pub or restaurant, are often noisy. The detection of sound occurs in the inner ear, which also possesses an active mechanism to mechanically amplify sound vibrations. Because the active mechanism can be regulated by the nervous system, it may already play a part in analyzing complex acoustic scenes. However, investigations of these questions have been hindered by a lack of experimental tools to assess the inner ear’s activity in relation to speech processing. Here, we develop a method to record otoacoustic emissions (OAEs) that relate to the harmonic structure of speech, a key feature of many speech parts. We use the novel tool to provide tentative evidence that the inner ear contributes to selective attention.Humans have a remarkable ability to selectively listen to one of several competing speakers and understand them despite the interfering voices. The cognitive processes involved in these tasks are typically attributed to the auditory cortex that receives its inputs from lower-level neural processing centers. However, extensive feedback loops exist between the lower-level structures and the cortex. In particular, descending efferent nerve fibers transmit information from the auditory cortex to the superior olivary complex and to the cochlear nuclei, and through the olivocochlear bundle from the superior olivary complex to the inner ear .The inner ear, or cochlea, detects sound vibrations by transducing them into electrical signals in the auditory nerve. However, the inner ear also aids the processing of sound. It spatially separates the different frequency components of a complex tone: high frequencies cause maximal vibration near the base of the organ and lower frequencies are detected at progressively more apical locations . This spThe active process is mediated by the inner ear’s mechanosensitive outer hair cells. These cells are innervated by one of two types of the olivocochlear fibers, the medial ones. Activation of the medial olivocochlear (MOC) fibers can reduce the mechanical amplification provided by the outer hair cells . Becausef1 and f2, and emerge in particular at the cubic distortion product frequencies 2f1 – f2 and 2f2 – f1. By convention, the two primary frequencies are chosen such that f1 < f2. The cubic distortion product 2f1 – f2 is then below the two primary frequencies and is referred to as the lower-sideband distortion product. Conversely, the upper-sideband distortion product 2f2 – f1 is higher than f1 and f2.The strength of the mechanical amplification in the cochlea, as well as its regulation through efferent feedback, can be assessed through distortion-product otoacoustic emissions (DPOAEs). A by-product of the active process’ compressive nonlinearity, DPOAEs are typically elicited by two pure tones of nearby frequencies Because of efferent feedback, DPOAEs from one ear are suppressed when stimulating the other ear with noise , and no significant difference from 0 , with p values of 2e-5 and 3e-4. One further subject showed significant relative attentional modulation to the female voice (FA), with a p value of 0.02. The remainder of the attentional modulation coefficients were statistically insignificant, with p values between 0.06 and 0.9.At the level of individual subjects, two subjects showed significant relative attentional modulations to the male voice (We developed a method to measure speech-DPOAEs, namely OAEs that were related to the harmonic structure of a speech signal. These OAEs were elicited by waveforms whose instantaneous frequency corresponded to that of particular harmonics of the fundamental frequency of the voiced parts of speech. They elicited distortion at other harmonics, and we measured these distortions by cross-correlating the microphone recording with the corresponding waveforms.We compared the speech-DPOAEs to conventional pure-tone DPOAEs, and found that, across the different subjects, the amplitudes of the speech-DPOAEs were correlated to those of the pure-tone DPOAEs. Moreover, analyzing pure-tone DPOAEs in a manner that was comparable to the speech-DPOAEs showed that the amplitude of the speech-DPOAEs was comparable to that of the pure-tone DPOAEs. This suggests that the speech-DPOAEs and pure-tone DPOAEs have indeed a common origin in the cochlea.Because the fundamental frequency of speech varies over time, the harmonics vary as well. The stimuli that we employed to elicit speech-DPOAEs, as well as the speech-DPOAEs themselves, were therefore not pure tones, but had a broader frequency spectrum. This enabled us to obtain the latency of the speech-DPOAEs, which provides further information on the origin of the emissions.OAEs have been found to consist of two components, one with a long latency of many cycles and another with a short one of maximally a few cycles of delay . The twoWe found a latency of the speech-DPOAEs of only 2.3 ms, corresponding to ∼1.6 cycles. Although the speech-DPOAEs result from the lower-sideband distortion, their short delay reveals that they are dominated by the short-latency component. This deviation from the behavior of pure-tone DPOAEs may reflect the varying frequency of the speech-DPOAEs, which can introduce negative interference in the long-latency component. Because the phase of the latter changes rapidly with frequency, variation in frequency can indeed lead to significant cancellation effects. The phase of the short-latency component, in contrast, depends barely on frequency, except for the phase changes associated with the varying primary frequencies themselves . The funThe speech-DPOAE related to the male voice had a larger amplitude than that related to the female voice. This behavior might reflect the different frequency ratios between the waveforms that we used to elicit the different speech-DPOAEs. Pure-tone DPOAEs have been found to be largest when the ratio of the primary frequencies 2/f1≈1.2 . The harTo investigate whether the speech-DPOAEs that we measured could in fact be used to investigate the effects of speech processing on the cochlea, we employed the speech-DPOAEs to study whether they were affected by selective attention to one of two competing voices. We found that the speech-DPOAEs related to the female voice were larger when the female voice was attended than when it was ignored. The speech-DPOAEs related to the male voice were not affected by attention.We can speculate that the lack of a significant effect for the male voice might reflect the poorer resolvability of the target harmonics. The speech-DPOAEs that were related to the female voice tracked the resolved harmonics. Their measurement therefore allowed to test whether cochlear activity at the locations of the resolved harmonics was modulated by selective attention. In contrast, the speech-DPOAEs for the male voice were related to unresolved harmonics. Our observation of an attentional modulation of the speech-DPOAEs related to the female, but not of those related to the male voice, is therefore consistent with an attentional modulation of cochlear activity regarding the resolved but not the unresolved harmonics of speech. In particular, the cochlea appears to facilitate selective attention to a voice through a larger mechanical response at the locations of the resolved harmonics, but not at the unresolved harmonics. Because only the resolved harmonics can be differentiated in the cochlea, an attentional modulation that aims to reduce background noise can indeed only sensibly operate on the resolved and not on the unresolved harmonics.The attentional effect on the amplitude of the speech-DPOAE related to the female voice that we observed is only 6.4% on average, corresponding to 0.54 dB. Although this effect is small, it is comparable to the MOC reflex that is elicited by broadband noise and changes DPOAE magnitudes between 0.5 and 2 dB . IntermoThe bootstrap analysis of the data validated the stability of the attentional modulation effect. Nevertheless, the large confidence interval for the mean attention estimate suggests considerable uncertainty as well as a large interindividual variability, in lines with recent observations on selective attention modulation of cochlear function when attending to tones .The attentional modulation of cochlear activity related to the harmonic structure of speech is reminiscent of the attentional effect on the brainstem response to voiced speech. As we have shown recently, the brainstem response at the fundamental frequency of continuous speech is modulated by selective attention . In partDPOAEs and other types of OAEs have been employed previously to investigate how cochlear activity can be affected by selective attention, such as auditory versus visual attention, but have yielded inconclusive results that include both positive  and negaOur method of assessing the attentional modulation of the inner ear’s activity relates directly to natural speech processing. The task of selective attention to speech was naturalistic with a high ecological validity, and with a high perceptual load. This factor may have contributed to our positive finding regarding a modulation of speech-DPOAEs through selective attention. However, because of the small sample size, the lack of effect for the male condition and the large margin of error of the effect, the evidence for attentional modulation that we obtained still needs to be treated with caution. Moreover, the modulation by selective attention was, at the level of individual subjects, only significant in a few cases. While we believe that the speech-DPOAEs that we introduced open a promising path to study selective attention to speech in the cochlea, further studies are required to replicate our findings, to firmly establish the attentional modulation, to investigate the impact of the ratio of the primary frequencies on the amplitude of the resulting speech-DPOAEs, and to investigate to which degree resolved versus unresolved harmonics lead to differences in the attentional modulation.In conclusion, the speech-DPOAEs that we have developed here provide a novel tool to measure inner-ear activity related to the processing of naturalistic speech. In particular, this enables to assess aspects of speech processing such as selective attention in a manner that fosters sustained attention of a participant and avoids potential neural adaptation to repeated stimuli. We therefore expect speech-DPOAEs and related complex OAEs to become a useful tool in further exploring how the inner ear contributes to the processing of complex real-world acoustic signals. They may also be relevant for a better understanding and diagnosis of poorly understood hearing impairments such as cochlear neuropathy or speech-in-noise deficits.