Classification of psychodermatological disorders: Proposal of a new international classification.

INTRODUCTION: Several classifications of psychodermatology disorders have been proposed, with most of them based on two to four main disorder category groups. However, there is, to date, no classification that has resulted from a consensus established by psychodermatology experts. The DSM-5-TR (Diagnostic and statistical manual of mental disorders (5th ed.), Text Revision) and the ICD-11 (International classification of diseases (11th revision)) also do not provide a systematized approach of psychodermatology disorders. Taking into consideration that classifications are a key pillar for a comprehensive approach to the pathologies of each branch of medicine, the proposal of a classification in psychodermatology appeared as a central need for the recognition of psychodermatological disorders, in an attempt to improve their recognition and, in that sense, to find a common language for the development of this subspecialty that crosses dermatology and psychiatry. METHODS: Previously published classifications in psychodermatology were critically reviewed and discussed by expert opinion from an international multidisciplinary panel of 16 experts in psychodermatology and a new classification system is proposed, considering classical concepts in general dermatology and psychopathology. RESULTS: Two main categories of disorders are presented (a main group related to primary mental health disorders and another main group related to primary skin disorders), which are subsequently subdivided into subgroups considering pathophysiological and phenomenological similarities, including key aspects of dermatological examination, namely the presence of visible skin lesions (primary and secondary skin lesions) and psychopathological correlates. CONCLUSION: This new classification aims to unify previous classifications, systematize the disorders that belong to psychodermatology and highlight their tenuous boundaries, to improve their management. It has been built and approved by the Psychodermatology Task Force of the European Academy of Dermatology and Venereology (EADV), the European Society for Dermatology and Psychiatry (ESDaP) and the Association for Psychoneurocutaneous Medicine of North America (APMNA).

Personality Disorders and Traits of ABC Clusters in Fibromyalgia in a Neurological Setting.

BACKGROUND: Evidence suggests that there is substantial comorbidity between fibromyalgia and Axis II pathology (i.e., personality disorders-PDs). The aim of the current study was to find out the exact cluster (A, B, C) of PDs or traits that are more prominent in FM and may be predictors of FM diagnosis. METHODS: Data from 86 subjects (53 with FM and 33 controls without FM) were analyzed in an observational, cross-sectional, comparative study in a neurological setting. The assessment of categorical PDs and traits was performed independently with the Structured Clinical Interview for Personality Disorders (SCID-II). Binary logistic regression was used to determine FM predictors among PD traits. RESULTS: Compared with controls, FM patients had a higher rate of PD diagnoses (56.7 vs. 18.2%, p < 0.001). However, the rate was significantly higher only for borderline PD diagnosis (28.3% vs. 6.1% p < 0.05). The binary logistic regression analysis showed that schizotypal and schizoid (cluster A), borderline (cluster B), and dependent (cluster C) personality traits may be significant predictors of fibromyalgia (Nagelkerke R2 = 0.415). CONCLUSIONS: Our results may reflect the association of FM with personality traits of all three PD clusters: A (eccentric), B (dramatic), and C (anxious). However, the most consistent evidence seems to be for borderline PD.

Chronobiological Predictors of Depression Relapse: for Prognostic Model Development - a Systematic Review.

BACKGROUND: Depressive disorders are characterized by fluctuating symptom severity, and developing an individual prognostic model for relapse is crucial for effective prevention. Chronobiological factors are poorly understood in this context. METHODS: A systematic search was conducted to identify articles related to the prognosis of depression recurrence based on chronobiological factors. Relevant clinical studies were included, while reviews and case reports were excluded. A total of 14 articles were selected for review. RESULTS: The included articles focused on various chronobiological factors, including circadian biorhythms, individual chronotype, mood swings, seasonal patterns, diurnal cortisol fluctuations, and light therapy. The accuracy of personified prognosis ranged from 22.7% to 93.8%, and the prognostic value of specific predictors in group prognosis varied from 23.9% to 54%. Methodological differences and limitations hindered direct comparison and clinical applicability. CONCLUSIONS: Developing precise and practical models for depression recurrence prognosis remains limited. Parameters of circadian rhythm showed the highest accuracy for short-term prognosis, and the use of digital technologies, including AI, enhanced prognostic value. Relapse seasonality had limited practical applicability. Integrating other chronobiological factors into prognostic models requires further research. Utilizing digital technologies, including AI, can improve the accuracy and range of personified prognosis. Only a few selected parameters of the human chronobiological system were considered in the examined studies. There are indications of the other chronobiological factors that could be included in the integrated prognostic model of recurrence for its further improvement.

Perceived Stigmatization among Dermatological Outpatients Compared with Controls: An Observational Multicentre Study in 17 European Countries.

Perceived stigmatization places a large psychosocial burden on patients with some skin conditions. Little is known about the experience of stigmatization across a wide range of skin diseases. This observational cross-sectional study aimed to quantify perceived stigmatization and identify its predictors among patients with a broad spectrum of skin diseases across 17 European countries. Self-report questionnaires assessing perceived stigmatization and its potential predictors were completed by 5,487 dermatology outpatients and 2,808 skin-healthy controls. Dermatological diagnosis, severity, and comorbidity were clinician-assessed. Patients experienced higher levels of perceived stigmatization than controls (p < 0.001, d = 0.26); patients with psoriasis, atopic dermatitis, alopecia, and bullous disorders were particularly affected. Multivariate regression analyses showed that perceived stigmatization was related to sociodemographic (lower age, male sex, being single), general health-related (higher body mass index, lower overall health), disease-related (higher clinician-assessed disease severity, presence of itch, longer disease duration), and psychological (greater distress, presence of suicidal ideation, greater body dysmorphic concerns, lower appearance satisfaction) variables. To conclude, perceived stigmatization is common in patients with skin diseases. Factors have been identified that will help clinicians and policymakers to target vulnerable patient groups, offer adequate patient management, and to ultimately develop evidence-based interventions.

Chitosan Composites with Bacterial Cellulose Nanofibers Doped with Nanosized Cerium Oxide: Characterization and Cytocompatibility Evaluation.

In this work, new composite films were prepared by incorporating the disintegrated bacterial cellulose (BCd) nanofibers and cerium oxide nanoparticles into chitosan (CS) matrices. The influence of the amount of nanofillers on the structure and properties of the polymer composites and the specific features of the intermolecular interactions in the materials were determined. An increase in film stiffness was observed as a result of reinforcing the CS matrix with BCd nanofibers: the Young's modulus increased from 4.55 to 6.3 GPa with the introduction of 5% BCd. A further increase in Young's modulus of 6.7 GPa and a significant increase in film strength (22% increase in yield stress compared to the CS film) were observed when the BCd concentration was increased to 20%. The amount of nanosized ceria affected the structure of the composite, followed by a change in the hydrophilic properties and texture of the composite films. Increasing the amount of nanoceria to 8% significantly improved the biocompatibility of the films and their adhesion to the culture of mesenchymal stem cells. The obtained nanocomposite films combine a number of favorable properties (good mechanical strength in dry and swollen states, improved biocompatibility in relation to the culture of mesenchymal stem cells), which allows us to recommend them for use as a matrix material for the culture of mesenchymal stem cells and wound dressings.

Students' mental health during the pandemic: results of the observational cross-sectional COVID-19 MEntal health inTernational for university Students (COMET-S) study.

Introduction: The aim of the study was to search rates of depression and mental health in university students, during the COVID-19 pandemic. Materials and methods: This is an observational cross-sectional study. A protocol gathering sociodemographic variables as well as depression, anxiety and suicidality and conspiracism was assembled, and data were collected anonymously and online from April 2020 through March 2021. The sample included 12,488 subjects from 11 countries, of whom 9,026 were females (72.2%; aged 21.11 ± 2.53), 3,329 males (26.65%; aged 21.61 ± 2.81) and 133 "non-binary gender" (1.06%; aged 21.02 ± 2.98). The analysis included chi-square tests, correlation analysis, ANCOVA, multiple forward stepwise linear regression analysis and Relative Risk ratios. Results: Dysphoria was present in 15.66% and probable depression in 25.81% of the total study sample. More than half reported increase in anxiety and depression and 6.34% in suicidality, while lifestyle changes were significant. The model developed explained 18.4% of the development of depression. Believing in conspiracy theories manifested a complex effect. Close to 25% was believing that the vaccines include a chip and almost 40% suggested that facemask wearing could be a method of socio-political control. Conspiracism was related to current depression but not to history of mental disorders. Discussion: The current study reports that students are at high risk for depression during the COVID-19 pandemic and identified specific risk factors. It also suggested a role of believing in conspiracy theories. Further research is important, as it is targeted intervention in students' groups that are vulnerable both concerning mental health and conspiracism.

Non-Psychiatrist Healthcare Professionals? Attitudes Toward Patients with Mental Disorders: Lower Scores in Social Distance as a Fragile Facet of Public Stigma Against Depression.

BACKGROUND: The stigmatization by healthcare professionals (HP) of patients suffering from mental disorders is an important problem that interferes with the delivery of medical assistance. Social distancing by HP is an integral part of stigmatization, which differs between various mental disorders, as well as between psychiatrists (PSY) versus nonpsychiatrist healthcare professionals (NPHP). SUBJECTS AND METHODS: The study included 141 HP: PSY (n=20; 36.2±4.2 y.o.) and NPHP (n=121; 25.9±2.2 y.o.). The NPHP group included general practitioners (GP)/physicians (n=29; 20.6%), surgeons (n=19; 13.5%), obstetrician-gynecologists (n=26; 18.4%), neurologists (n=11; 7.8%), pediatricians (n=6; 4.3%), and other subspecialists (including urologists, tuberculosis specialists, ophthalmologists and dermatologists) (n=30; 21.3%). The modified Bogardus Social Distance Self-Assessment Scale (BSDS) was used to evaluate the indicators of social distance phenomena. The assessment was performed by HP for the following groups of patients with the following mental disorders: alcohol use disorder, bipolar disorder, depression, drug addiction, epilepsy, mental retardation, personality disorder, schizophrenia. All statistical calculations were performed using IBM SPSS-27 software (IBM Corp. 2021, licensed to Samara State Medical University). P-value ≤0.05 was determined as significant for the between-group (PSY vs NPHP) comparisons using a nonparametric Mann-Whitney U-test. RESULTS: Our data analysis showed that HP achieved varying social distance scores for patients depending on the type of mental disorder, but with common trends among PSY and NPHPs. The mean (SD) scores of social distance ranged from 3.65(1.50) for depression to 5.25 (1.74) for drug addiction in the PSY, versus 3.44 (1.69), 6.19 (1.37) in NPHP, respectively. As compared to PSY, mean BSDS total scores were greater in the NPHP group, notably in the obstetricians-gynecologist - 6.27(1.40), and GP - 6.62 (0.90) groups, with similar trends of differing attitudes appeared among pediatricians - 7.00 (0.01) - regarding drug addiction, whereas the neurologists demonstrated a tendency towards lower social distance in relation to patients with depression - 2.27 (1.68), and epilepsy - 2.82 (1.47). CONCLUSIONS: Social distance measures by PSY and NPHP groups in contemporary Russia were highest in relation to patients with drug addiction, and lowest scores for depression and epilepsy. Stigmatization among HPs seems to influence health care delivery to certain categories of patients, which calls for further investigation. Higher social distance scores for patients with drug addiction might be related to higher stigma and lack of compassion toward these patients. Conversely, lower scores of social distance and corresponding emotional acceptance of people with depression by HP might interfere in the timely diagnosis and availability of appropriate care at an early stage amenable to treatment. This might reflect the cultural context of depressive mentality in Russia, or elevated prevalence of depressive states among HP. We propose interventions aiming to destigmatize mental disorders by targeting particular subgroups of vulnerable patients and also certain representatives of HP community.

Anxiety, Depression and Suicidality in Healthcare Workers during the COVID-19 Pandemic: The Russian Study Sample of the COMET-G Project.

BACKGROUND: During the COVID-19 pandemic healthcare workers have been under pressure of high workload and an increased risk of contracting the SARS-Cov-2 virus, while confronting the most tragic and devastating aspects of the pandemic-related medical realities. These factors could lead to severe distress with potential consequences for productivity in performing professional duties, and substantially increased risk for affective reactions, including clinical states of anxiety, depression and suicidality as compared to the general population. Thus, we aimed to investigate the changes in rates of anxiety, depression and suicidality in response to the pandemic among medical staff as compared to a sample of the general population and to the period of prepandemic time. SUBJECTS AND METHODS: This study is part of the large-scale, international multicentre COMET-G project. We assessed the extents of anxiety, depression and suicidality risks using the Stait-Trait Anxiety Inventory (STAI) with a cut-off score 39/40, Center for Epidemiologic Studies Depression Scale (CES-D) with a cut-off score 23/24, and the Risk Assessment Suicidality Scale (RASS) with a cut-off score 499/500, respectively, in samples of Russian healthcare workers and the general population. RESULTS: Among 7777 respondents participating in the study, responses to a query about occupation indicated 1216 healthcare workers. 45.8% of medical staff vs 40.4% of non-medical staff (χ2=12.42, p<0.001) reported the increased anxiety, in excess of the clinical anxiety state threshold score of 39 according to the STAI. High suicidality risks, according to a RASS score > 500, were reported by 8.2% of medical professionals vs 10.6% of non-medical personnel (χ2=6.35, p=0.012). The increase in depression rates, including cases of clinical depression according to the threshold of CES-D ≥ 24, did not differ between the groups. CONCLUSIONS: A larger proportion of healthcare system staff, as compared to the general population, reported a significant increase in anxiety in response to the pandemic. Compared to medical doctors, other healthcare system workers had a significantly higher prevalence of depression and suicidality rates. Exploratory analysis suggested that it was not the occupation per se, but rather the burden of meaningful working duties that could be associated with psychological defense mechanisms against depression and suicidality among medical staff.

pH-Sensitive Drug Delivery System Based on Chitin Nanowhiskers-Sodium Alginate Polyelectrolyte Complex.

Polyelectrolyte complexes (PECs), based on partially deacetylated chitin nanowhiskers (CNWs) and anionic polysaccharides, are characterized by their variability of properties (particle size, ζ-potential, and pH-sensitivity) depending on the preparation conditions, thereby allowing the development of polymeric nanoplatforms with a sustained release profile for active pharmaceutical substances. This study is focused on the development of hydrogels based on PECs of CNWs and sodium alginate (ALG) for potential vaginal administration that provide controlled pH-dependent antibiotic release in an acidic vaginal environment, as well as prolonged pharmacological action due to both the sustained drug release profile and the mucoadhesive properties of the polysaccharides. The desired hydrogels were formed as a result of both electrostatic interactions between CNWs and ALG (PEC formation), and the subsequent molecular entanglement of ALG chains, and the formation of additional hydrogen bonds. Metronidazole (MET) delivery systems with the desired properties were obtained at pH 5.5 and an CNW:ALG ratio of 1:2. The MET-CNW-ALG microparticles in the hydrogel composition had an apparent hydrodynamic diameter of approximately 1.7 µm and a ζ-potential of -43 mV. In vitro release studies showed a prolonged pH-sensitive drug release from the designed hydrogels; 37 and 67% of MET were released within 24 h at pH 7.4 and pH 4.5, respectively. The introduction of CNWs into the MET-ALG system not only prolonged the drug release, but also increased the mucoadhesive properties by about 1.3 times. Thus, novel CNW-ALG hydrogels are promising carriers for pH sensitive drug delivery carriers.

Developing Oligo Probes for Chromosomes Identification in Hemp (Cannabis sativa L.).

Hemp (Cannabis sativa L., 2n = 20) is a valuable crop that is successfully used as a food, technical and medicinal crop. It is a dioecious plant with an XX\XY sex determination system. Some chromosomes of C. sativa have almost the same lengths and centromeric indexes. Cytogenetic markers help to distinguish similar plant chromosomes, including sex chromosomes, which is important for the breeding process. Two repeats (CS-1 and CS-237) were used to develop labeled oligo-probes for rapid and low-cost oligo-FISH. These oligos can be recommended for use as cytological markers to distinguish sex chromosomes (X and Y) and somatic chromosome pairs 3, 6, and 8 by rapid oligo-FISH in a short time.

Study and Physical Mapping of the Species-Specific Tandem Repeat CS-237 Linked with 45S Ribosomal DNA Intergenic Spacer in Cannabis sativa L.

Hemp (Cannabis sativa L.) is a valuable crop and model plant for studying sex chromosomes. The scientific interest in the plant has led to its whole genome sequencing and the determination of its cytogenetic characteristics. A range of cytogenetic markers (subtelomeric repeat CS-1, 5S rDNA, and 45S rDNA) has been mapped onto hemp's chromosomes by fluorescent in situ hybridization (FISH). In this study, another cytogenetic marker (the tandem repeat CS-237, with a 237 bp monomer) was found, studied, and localized on chromosomes by FISH. The signal distribution and karyotyping revealed that the CS-237 probe was localized in chromosome 6 with one hybridization site and in chromosome 8 with two hybridization sites, one of which colocalizes with the 45S rDNA probe (with which a nucleolus organizer region, NOR, was detected). A BLAST analysis of the genomic data and PCR experiments showed that the modified CS-237 monomers (delCS-237, 208 bp in size) were present in the intergenic spacers (IGSs) of hemp 45S rDNA monomers. Such a feature was firstly observed in Cannabaceae species. However, IGS-linked DNA repeats were found in several plant species of other families (Fabaceae, Solanaceae, and Asteraceae). This phenomenon is discussed in this article. The example of CS-237 may be useful for further studying the phenomenon as well as for the physical mapping of hemp chromosomes.

Body dysmorphia in common skin diseases: results of an observational, cross-sectional multicentre study among dermatological outpatients in 17 European countries.

BACKGROUND: Body dysmorphic disorder (BDD) is a common psychiatric disorder associated with high costs for healthcare systems as patients may repeatedly ask for different, often not effective, interventions. BDD symptoms are more prevalent in patients with dermatological conditions than in the general population, but there are no large sample studies comparing the prevalence of BDD symptoms between patients with dermatological conditions and healthy skin controls. OBJECTIVES: To compare the prevalence of BDD symptoms between patients with different dermatological conditions and healthy skin controls and to describe sociodemographic, physical and psychological factors associated with BDD symptoms to identify patients who may have a particularly high chance of having this condition. METHODS: This observational, cross-sectional, comparative multicentre study included 8295 participants: 5487 consecutive patients with different skin diseases (56% female) recruited among dermatological outpatients at 22 clinics in 17 European countries, and 2808 healthy skin controls (66% female). BDD symptoms were assessed by the Dysmorphic Concern Questionnaire. Sociodemographic data and information on psychological factors and physical conditions were collected. Each patient was given a dermatological diagnosis according to ICD-10 by a dermatologist. The study was registered with number DRKS00012745. RESULTS: The average participation rate of invited dermatological patients was 82.4% across all centres. BDD symptoms were five times more prevalent in patients with dermatological conditions than in healthy skin controls (10.5% vs. 2.1%). Patients with hyperhidrosis, alopecia and vitiligo had a more than 11-fold increased chance (adjusted Odds Ratio (OR) > 11) of having BDD symptoms compared with healthy skin controls, and patients with atopic dermatitis, psoriasis, acne, hidradenitis suppurativa, prurigo and bullous diseases had a more than sixfold increased chance (adjusted OR > 6) of having BDD symptoms. Using a logistic regression model, BDD symptoms were significantly related to lower age, female sex, higher psychological stress and feelings of stigmatization. CONCLUSIONS: Clinical BDD symptoms are significantly associated with common dermatological diseases. As such symptoms are associated with higher levels of psychological distress and multiple unhelpful consultations, general practitioners and dermatologists should consider BDD and refer patients when identified to an appropriate service for BDD screening and management.

Identification of Different Profiles of Illness Perception in COPD Patients: Results of Cluster Analysis.

Background: Chronic obstructive pulmonary disease (COPD) is a widespread, late-diagnosed, and difficult-to-treat disease that influences the quality of life. Despite the availability of a wide range of drugs for the treatment of COPD, none of them provides a complete cure, while the leading risk factors (primarily, smoking) persist. In this regard, illness perception and medical behavior play a key role. Methods: The study design was cross-sectional and included 143 stable outpatients (107 men, mean age 66 ± 7.5, FEV1 51.5 ± 16.5%) who attended the faculty therapy clinic of Sechenov University. The patients were examined pulmonologically and psychiatrically (Hamilton depression and anxiety rating scales). Illness perception was assessed by a brief version of the Illness perception questionnaire (brief IPQ). Results: There were no significant demographic differences and differences in the clinical severity of the disease between the selected groups. Patients in the distressed group had a longer duration of illness, a higher prevalence of anxiety and depression, and more severe dyspnea after a 6-minute walk test. In contrast, patients in the disregarding group had a significantly higher prevalence of smokers and a higher number of cigarettes smoked daily, and a lower prevalence of anxiety and depression. The harmonic had the most optimal profile with low severity of anxiety and depression, but with a healthier attitude to smoking. Conclusion: Perception of illness in COPD patients has a significant impact on medical behavior and levels of anxiety and depression. As such, the perception of illness deserves routine monitoring in clinical practice.

Comparative Analysis of the Functional Properties of Films Based on Carrageenans, Chitosan, and Their Polyelectrolyte Complexes.

The influence of the structural features of carrageenan on the functional properties of the films was studied. The carrageenans and chitosan films, as well as three-layer films containing a polyelectrolyte complex (PEC) of the two, were prepared. The X-ray diffractograms of carrageenan films reflected its amorphous structure, whereas chitosan and three-layer films were characterized by strong reflection in the regions of 20° and 15° angles, respectively. The SEM of the cross-sectional morphology showed dense packing of the chitosan film, as well as the layer-by-layer structure of different densities for the PEC. Among the tested samples, κ/ß-carrageenan and chitosan films showed the highest tensile strength and maximum elongation. Films containing the drug substance echinochrome were obtained. Mucoadhesive properties were assessed as the ability of the films to swell on the mucous tissue and their erosion after contact with the mucosa. All studied films exhibited mucoadhesive properties. All studied films exhibited mucoadhesive properties which depended on the carrageenans structure. Multilayer films are stronger than single-layer carrageenan films due to PEC formation. The resulting puncture strength of the obtained films was comparable to that of commercial samples described in the literature.

Interactions between Anxiety Levels and Life Habits Changes in General Population during the Pandemic Lockdown: Decreased Physical Activity, Falling Asleep Late and Internet Browsing about COVID-19 Are Risk Factors for Anxiety, whereas Social Media Use Is not.

BACKGROUND: The COVID-19 pandemic has substantially contributed to increased anxiety rates among the general population worldwide. Pandemic-related health anxiety and worries about getting COVID-19 can lead to generalized anxiety and anxiety somatization, which, together with insalubrious daily life habits, are risk factors of worsening somatic health in people with SARS-Cov-2 infection. SUBJECTS AND METHODS: The current study is a part of the COMET-G project (40 countries, n=55589; approved by the Ethics Committee of the Aristotle University of Thessaloniki), which represents an intermediate analysis of data collected anonymously via online links from a national sample of the Russian general population (n=9936, 31.09±12.16 y.o., 58.7% females) to estimate anxiety using STAI-S and self-reported changes in anxiety and life habits (physical activity, nutrition and weight, internet use, sleep) during the lockdown. All statistical calculations (descriptive statistics, between group comparisons using chi-square test, MANOVA, ANOVA, significant at p<0.05) were performed with IBM SPSS 27. RESULTS: Overall STAI-S scores were 29±5.4, a subjective feeling of anxiety increase was reported in 40.3% of respondents (43.9% significantly > in females), worsening to clinical anxiety in 2.1% (2.4% > in females). 54.2% of respondents reported decreased physical activity, 33.1% gained weight, 72% used internet more often, 52.6% experienced worries related to the information about COVID-19 (56.8% > in females). 88% experienced worsened sleep quality, 69.2% stayed up until late, 23.2% took sleeping pills, and 31% had nightmares in which they felt trapped. To ANOVA, such life habits as reduced physical activity during the lockdown, increased time spent online, internet browsing about COVID-19, tendency to stay up late, use of sleeping pills and disturbing dreams with scenario of being trapped were significantly related to worsening of clinical anxiety. However, eating behaviour, weight changes, and social media use did not contribute to the clinical anxiety increase. CONCLUSIONS: Factors of decreased physical activity and sleep disturbances related to the lockdown, as well as excessive internet browsing for information about COVID-19, emerged as risk factors for increased anxiety, more notably in women than in men. Preventive measures should be targeted against relevant factors imparting anxiety in the vulnerable population.

Nonspecific enzymatic hydrolysis of a highly ordered chitopolysaccharide substrate.

Chitin and chitosan can undergo nonspecific enzymatic hydrolysis by several different hydrolases. This susceptibility to nonspecific enzymes opens up many opportunities for producing chitooligosaccharides and low molecular weight chitopolysaccharides, since specific chitinases and chitosanases are rare and not commercially available. In this study, chitosan and chitin were hydrolyzed using several commercially available hydrolases. Among them, cellulases with the highest specific activity demonstrated the best activity, as indicated by the rapid decrease in viscosity of a chitosan solution. The hydrolysis of chitosan by nonspecific enzymes generated a sugar release that corresponded to the decrease in the degree of polymerization. This decrease reached a maximum of 3.3-fold upon hydrolysis of 10% of the sample. Cellulases were better than lysozyme or amylases at hydrolyzing chitosan and chitin. Analysis of 13C CP-MAS NMR and FTIR spectra of chitin after cellulase treatment revealed changes in the chitin crystal structure related to rearrangement of inter- and intramolecular H-bonds. The structural changes and decreases in crystallinity allowed dissolution of chitin molecules of high molecular weight and enhanced the solubility of chitin in alkali by 10-12% compared to untreated chitin.

Bacterial Cellulose (Komagataeibacter rhaeticus) Biocomposites and Their Cytocompatibility.

A series of novel polysaccharide-based biocomposites was obtained by impregnation of bacterial cellulose produced by Komagataeibacter rhaeticus (BC) with the solutions of negatively charged polysaccharides-hyaluronan (HA), sodium alginate (ALG), or κ-carrageenan (CAR)-and subsequently with positively charged chitosan (CS). The penetration of the polysaccharide solutions into the BC network and their interaction to form a polyelectrolyte complex changed the architecture of the BC network. The structure, morphology, and properties of the biocomposites depended on the type of impregnated anionic polysaccharides, and those polysaccharides in turn determined the nature of the interaction with CS. The porosity and swelling of the composites increased in the order: BC-ALG-CS > BC-HA-CS > BC-CAR-CS. The composites show higher biocompatibility with mesenchymal stem cells than the original BC sample, with the BC-ALG-CS composite showing the best characteristics.

Cytocompatibility of Bilayer Scaffolds Electrospun from Chitosan/Alginate-Chitin Nanowhiskers.

In this work, a bilayer chitosan/sodium alginate scaffold was prepared via a needleless electrospinning technique. The layer of sodium alginate was electrospun over the layer of chitosan. The introduction of partially deacetylated chitin nanowhiskers (CNW) stabilized the electrospinning and increased the spinnability of the sodium alginate solution. A CNW concentration of 7.5% provided optimal solution viscosity and structurization due to electrostatic interactions and the formation of a polyelectrolyte complex. This allowed electrospinning of defectless alginate nanofibers with an average diameter of 200-300 nm. The overall porosity of the bilayer scaffold was slightly lower than that of a chitosan monolayer, while the average pore size of up to 2 µm was larger for the bilayer scaffold. This high porosity promoted mesenchymal stem cell proliferation. The cells formed spherical colonies on the chitosan nanofibers, but formed flatter colonies and monolayers on alginate nanofibers. The fabricated chitosan/sodium alginate bilayer material was deemed promising for tissue engineering applications.

Functional Decoupling of Language and Self-Reference Networks in Patients with Persistent Auditory Verbal Hallucinations.

BACKGROUND: Accumulating neuroimaging evidence suggests that abnormal intrinsic neural activity could underlie auditory verbal hallucinations (AVH) in patients with schizophrenia. However, little is known about the functional interplay between distinct intrinsic neural networks and their association with AVH. METHODS: We investigated functional network connectivity (FNC) of distinct resting-state networks as well as the relationship between FNC strength and AVH symptom severity. Resting-state functional MRI data at 3 T were obtained for 14 healthy controls and 10 patients with schizophrenia presenting with persistent AVH. The data were analyzed using a spatial group independent component analysis, followed by constrained maximal lag correlations to determine FNC within and between groups. RESULTS: Four components of interest, comprising language, attention, executive control networks, as well as the default-mode network (DMN), were selected for subsequent FNC analyses. Patients with persistent AVH showed lower FNC between the language network and the DMN (p < 0.05, corrected for false discovery rate). FNC strength, however, was not significantly related to symptom severity, as measured by the Psychotic Symptom Rating Scale. CONCLUSION: These findings suggest that disrupted FNC between a speech-related system and a network subserving self-referential processing is associated with AVH. The data are consistent with a model of disrupted self-attribution of speech generation and perception.