Differential expression and alternative splicing analyses of multiple tissues reveal albinism-associated genes in the Wels catfish (Silurus glanis)

Albinism is a widespread departure from a typical body colouration due to altered melanin production. The Wels catfish (Silurus glanis) is among the largest freshwater fish species in the world, and albino individuals occur both in the wild and in aquaculture. Here, we performed transcriptome-wide analysis of albino and normally pigmented S. glanis using four tissues (skin, dorsal fin, whole eye and liver) to identify genes associated with albinism by exploring patterns of differential expression (DE) and differential alternative splicing (DAS). Multi-tissue analyses revealed a large number of genes in skin (n = 1355) and fin (n = 614) tissue associated with the albino phenotype in S. glanis, while the number of DE genes in eye and liver tissues was lower (n = 188, n = 189, respectively). Several DE genes across multiple tissues were detected as the most promising candidates (e.g., hsp4, hsp90b1, raph1, uqcrfs1, adcy-family and wnt-family) potentially causally linked to the albino phenotype in Wels catfish. Moreover, our findings supported earlier observations of physiological differences between albino and normally pigmented individuals, particularly in energy metabolism and immune response. In contrast, there were only a few pigmentation-related genes observed among DAS genes (4 in skin, 2 in fin), the overlap between DAS and DE genes was low (n = 25) and did not include known pigmentation-related genes. This suggests that DAS and DE in Wels catfish are, to a large extent, independent processes, and the observed alternative splicing cases are probably not causally linked with albinism in S. glanis. This work provides the first transcriptome-wide multi-tissue insights into the albinism of Wels catfish and serves as a valuable resource for further understanding the genetic mechanisms of pigmentation in fish.

Amygdala-derived-EEG-fMRI-pattern neurofeedback for the treatment of chronic post-traumatic stress disorder. A prospective, multicenter, multinational study evaluating clinical efficacy

We conducted a prospective, single arm, multisite, multinational, open label trial assessing the safety and efficacy of a novel amygdala derived neurofeedback treatment, designated Amygdala-Derived-EFP, for chronic PTSD. Participants, including veterans and civilians, underwent screening, training, 15 neurofeedback sessions over 8 weeks and; baseline, termination (8 weeks) and 3 month post treatment assessments with validated measures. The primary endpoint was more than 50 % of the participants demonstrating a Minimally Clinically Important Difference (MCID) defined as a 6-point reduction, on the Clinician Administered PTSD Scale (CAPS-5) total score at 3 months. Secondary measures included the PCL-5, ERQ, PHQ-9, and CGI. Statistical analyses were performed using SAS®V9.4. The primary endpoint was met, with a CAPS-5 MCID response rate of 66.7 %. The average reduction in CAPS-5 total scores at 3 month follow up was 13.5 points, more than twice the MCID. Changes from baseline in CAPS-5, PCL-5, PHQ-9 scores at 8 weeks and the 3 month follow-up demonstrated statistically significant improvements in response and; demonstrated effect sizes ranging from 0.46 to 1.07. Adverse events were mild and resolved after treatment. This study builds on prior research demonstrating similar outcomes using amygdala-derived neurofeedback. Positive attributes of this therapy include monitoring by non-physician personnel, affordability, accessibility, and tolerability.

High-Q Magnetic Levitation and Control of Superconducting Microspheres at Millikelvin Temperatures

We report the levitation of a superconducting lead-tin sphere with 100  μm diameter (corresponding to a mass of 5.6  μg) in a static magnetic trap formed by two coils in an anti-Helmholtz configuration, with adjustable resonance frequencies up to 240 Hz. The center-of-mass motion of the sphere is monitored magnetically using a dc superconducting quantum interference device as well as optically and exhibits quality factors of up to 2.6×10^{7}. We also demonstrate 3D magnetic feedback control of the motion of the sphere. The setup is housed in a dilution refrigerator operating at 15 mK. By implementing a cryogenic vibration isolation system, we can attenuate environmental vibrations at 200 Hz by approximately 7 orders of magnitude. The combination of low temperature, large mass, and high quality factor provides a promising platform for testing quantum physics in previously unexplored regimes with high mass and long coherence times.

A 16-month longitudinal investigation of risk and protective factors for mental health outcomes throughout three national lockdowns and a mass vaccination campaign: Evidence from a weighted Israeli sample during COVID-19

BACKGROUND

COVID-19 is an ongoing global crisis, with a multitude of factors that affect mental health worldwide. We explored potential predictors for the emergence and maintenance of depression, anxiety, and posttraumatic stress symptoms (PTSS) in the general population in Israel.

METHODS

Across the span of 16 months, 2478 people completed a repeated self-report survey which inquired psychiatric symptoms and pandemic related stress factors (PRSF). We applied mixed-effects models to assess how each stressor contributes to depression, anxiety and PTSS at each time point, and longitudinally assessed participants who completed at least two consecutive surveys (n = 400). We weighted our sample to increase representativeness of the population.

RESULTS

Fatigue was the strongest predictor for depression, anxiety and PTSS at all time points, and predicted deterioration overtime. Financial concerns associated with depression and anxiety at all time points, and with their deterioration overtime. Health related concerns were uniquely associated with anxiety and PTSS at all time points and their deterioration, but not with depression. Improvement in sense of protection overtime associated with decrease in depression and anxiety. Hesitancy towards vaccination was associated to higher financial concerns and lower sense of protection by the authorities.

CONCLUSIONS

Our findings accentuate the multitude of risk factors for psychiatric morbidity during COVID-19, and the centrality of fatigue in determining mental health outcomes.

The Psychedelic Renaissance in Clinical Research: A Bibliometric Analysis of Three Decades of Human Studies with Psychedelics

Psychedelics were used in the treatment of psychiatric conditions prior to their prohibition in the late 1960s. In the past three decades, there is a revived research interest in the therapeutic potential of psychedelic drugs with expected FDA approvals for treatment of various conditions. Given the exponential scientific growth of this field, we sought to characterize, analyze, and visualize trends in its top-cited articles. Bibliometric analyses are quantitative approaches to characterize a scientific field, including evaluation of the impact of academic literature. The bibliometric analysis and visualizations were conducted with R-tools for comprehensive science mapping. The top-cited 100 articles were cited between 82 and 668 times (median 125; mean 158). Fifty-four percent of the T100 articles were produced in the past decade (2010-2020). Network and author impact analysis highlighted key figures and primary collaboration networks within the top 100 publications. UK, USA, Switzerland, Spain, and Brazil lead the field. Results are discussed in terms of research growth, access, diversity, and the distribution of knowledge and experience in the field. These aggregated data and insights on the second wave of psychedelic research facilitate research evaluation, data-driven funding policies, and a practical map for researchers and clinicians entering the field.

The association between naturalistic use of psychedelics and co-occurring substance use disorders

OBJECTIVE

Classic psychedelics (LSD, psilocybin, and peyote/mescaline) have been used to support addiction treatment in a variety of contexts ranging from ceremonial use to clinical trials. The aim of this study was to test the hypothesis that past naturalistic use of classic psychedelics would be associated with decreased prevalence of substance use disorder, when controlling for known confounders.

METHODS

This cross-sectional study used 2017 NSDUH survey data to evaluate the association between past use of the classic psychedelics LSD, psilocybin and peyote/mescaline and past year substance dependence or abuse. We calculated adjusted odds ratios by multivariate logistic regression, controlling for a range of sociodemographic variables, use of non-psychedelic illicit drugs and mental health related variables.

RESULTS

A total of 56,276 participants were included in this study. Past use of LSD and psilocybin were associated with increased odds of substance dependence or abuse compared to those who had never used psychedelics before, and this was more likely for those who had used LSD more recently. However, prior use of peyote or mescaline was associated with lower odds of past year substance dependence or abuse compared to people who had never used psychedelics before (aOR = 0.68, p < 0.001). Past use of classic psychedelics was not associated with nicotine dependence.

CONCLUSION

Past use of peyote/mescaline was associated with decreased odds of substance use disorder compared to people who had never used psychedelics before, while past use of LSD or psilocybin was not. It remains unclear whether this difference is due to pharmacological differences between these compounds or simply due to the context in which peyote/mescaline are traditionally taken. Future research should investigate why naturalistic use of different psychedelics is associated with different substance use disorder effects.

Sleep Difficulties Among COVID-19 Frontline Healthcare Workers

OBJECTIVE

To identify COVID-19 work-related stressors and experiences associated with sleep difficulties in HCW, and to assess the role of depression and traumatic stress in this association.

METHODS

A cross-sectional study of HCW using self-report questionnaires, during the first peak of the pandemic in Israel (April 2020), conducted in a large tertiary medical center in Israel. Study population included 189 physicians and nurses working in designated COVID-19 wards and a comparison group of 643 HCW. Mean age of the total sample was 41.7 ± 11.1, 67% were female, 42.1% physicians, with overall mean number of years of professional experience 14.2 ± 20. The exposure was working in COVID-19 wards and related specific stressors and negative experiences. Primary outcome measurement was the Insomnia Severity Index (ISI). Secondary outcomes included the Primary Care-Post Traumatic Stress Disorder Screen (PC-PTSD-5); the Patient Health Questionnaire-9 (PHQ-9) for depression; the anxiety module of the Patient-Reported Outcomes Measurement Information System (PROMIS); Pandemic-Related Stress Factors (PRSF) and witnessing patient suffering and death.

RESULTS

Compared with non-COVID-19 HCW, COVID-19 HCW were more likely to be male (41.3% vs. 30.7%) and younger (36.91 ± 8.81 vs. 43.14 ± 11.35 years). COVID-19 HCW reported higher prevalence of sleep difficulties: 63% vs. 50.7% in the non-COVID group (OR 1.62, 95% CI 1.15-2.29, p = 0.006), mostly difficulty maintaining sleep: 26.5% vs. 18.5% (OR 1.65, 95% CI 1.11-2.44, p = 0.012). Negative COVID-19 work-related experiences, specifically witnessing patient physical suffering and death, partially explained the association. Although past psychological problems and current depression and PTSD were associated with difficulty maintaining sleep, the main association remained robust also after controlling for those conditions in the full model.

CONCLUSION AND RELEVANCE

COVID-19 frontline HCW were more likely to report sleep difficulties, mainly difficulty maintaining sleep, as compared with non-COVID-19 HCW working at the same hospital. Negative patient-care related experiences likely mediated the increased probability for those difficulties. Future research is needed to elucidate the long-term trajectories of sleep difficulties among HCW during large scale outbreaks, and to identify risk factors for their persistence.

General hospital specialists' attitudes toward psychiatry: a cross-sectional survey in seven countries

OBJECTIVE

Psychiatric comorbidities are common in physical illness and significantly affect health outcomes. Attitudes of general hospital doctors toward psychiatry are important as they influence referral patterns and quality of care. Little is known about these attitudes and their cultural correlates. The aim of this study was to identify attitudes toward psychiatry among general hospital specialists in relation to culture of the practice setting and other clinician factors (gender, age, seniority and specialty).

METHODS

A cross-sectional, descriptive study was carried out in seven countries (New Zealand, China, Sri Lanka, Russia, Israel, Brazil, the Netherlands). Data were collected from senior medical staff of various disciplines using an updated version of Mayou and Smith's (1986) self-administered questionnaire.

RESULTS

A total of 889 hospital doctors participated. While favourable attitudes toward both psychiatric consultation and management were endorsed by a majority, significant differences were also observed between countries. Subgroup differences were mostly confined to gender, acuity of practice setting and specialty. For example, female doctors in Russia (χ²=7.7, p=0.0056), China (χ²=9.2, p=0.0025) and the Netherlands (χ²=5.7, p=0.0174) endorsed more positive attitudes compared with their male counterparts, but this gender effect was not replicated in the total sample. Chronic care specialists were overall more inclined to manage patients' emotional problems compared with those working in acute care (χ²=70.8, p (adjusted)<0.0001), a significant finding seen also in individual countries (China, New Zealand, the Netherlands, Russia). Physicians were more favourably disposed toward psychiatry compared with other specialists, especially surgeons, in all countries except Israel.

CONCLUSIONS

This study adds to evidence for the association of medical attitudes with individual clinician factors and demonstrates that the influence of these factors varies by country. Understanding these issues may help to overcome barriers and improve quality of care provided to general hospital patients.

Stimulant Treatment Effect on Anxiety Domains in Children with Attention-Deficit/Hyperactivity Disorder With and Without Anxiety Disorders: A 12-Week Open-Label Prospective Study

Objectives: The effect of stimulants on anxiety domains has not been systematically studied. We assessed prospectively the impact of stimulant treatment in children with attention-deficit/hyperactivity disorder (ADHD) on the severity of anxiety domains and on ADHD with comorbid anxiety disorders. Methods: Children with ADHD (n = 57, aged 6-15 years) started a stimulant or were switched from one stimulant to another. Assessments were conducted at four time points (baseline and weeks 2, 6, and 12) and consisted of parental questionnaires (ADHD rating scale, screen for child anxiety related disorders [SCARED]), and side effect questionnaire completed by a child psychiatrist. Results: A significant improvement in total SCARED scores was obtained after 12 weeks stimulant treatment in children both with and without anxiety disorders. Significant reductions were detected in generalized anxiety, separation anxiety, and school avoidance SCARED subscales, but not in panic and social anxiety subscales. ADHD symptoms significantly improved both in children with and without anxiety comorbidities. Conclusion: We found specific effects of stimulants on anxiety domains. Stimulant treatment, even for ADHD children diagnosed with comorbid anxiety disorders, is relatively safe regarding the risk of anxiety exacerbation. Moreover, the presence of anxiety symptoms or disorders does not interfere with the beneficial effect of the stimulants on the ADHD core symptoms. Clinical trial regestration number: IRB SMC-6893-20.

Association among income loss, financial strain and depressive symptoms during COVID-19: Evidence from two longitudinal studies

BACKGROUND

COVID-19 pandemic has major ramifications for global health and economy, with growing concerns about economic recession and implications for mental health. Here we investigated the associations between pandemic-related income loss with financial strain and mental health trajectories over a 1-month course, in two independent cohorts.

METHODS

Two independent studies were conducted in the U.S and in Israel at the beginning of the outbreak (March-April 2020, T1; study I: N = 2904, study II: N = 1267) and at a 1-month follow-up (T2; study I: N = 1318, study II: N = 241). Mixed-effects models were applied to assess associations among COVID-19-related income loss, financial strain, and pandemic-related worries about health, with anxiety and depression, controlling for multiple covariates including pre-COVID-19 income.

RESULTS

In both studies, income loss and financial strain were associated with greater depressive symptoms at T1, above and beyond T1 anxiety, worries about health, and pre-COVID-19 income. Worsening of income loss was associated with exacerbation of depression at T2 in both studies. Worsening of subjective financial strain was associated with exacerbation of depression at T2 in one study (US).

CONCLUSIONS

Income loss and financial strain were uniquely associated with depressive symptoms and their exacerbation over time, above and beyond pandemic-related anxiety. In times when a myriad of stressors are affecting mental health worldwide, our findings reveal specific links between the economic impact of COVID-19 and psychiatric outcomes.

Relationship between intelligence quotient measures and computerized neurocognitive performance in 22q11.2 deletion syndrome

Intelligence quotient (IQ) testing is standard for evaluating cognitive abilities in genomic studies but requires professional expertise in administration and interpretation, and IQ scores do not translate into insights on implicated brain systems that can link genes to behavior. Individuals with 22q11.2 deletion syndrome (22q11.2DS) often undergo IQ testing to address special needs, but access to testing in resource-limited settings is challenging. The brief Penn Computerized Neurocognitive Battery (CNB) provides measures of cognitive abilities related to brain systems and can screen for cognitive dysfunction. To examine the relation between CNB measures and IQ, we evaluated participants with the 22q11.2DS from Philadelphia and Tel Aviv (N = 117; 52 females; mean age 18.8) who performed both an IQ test and the CNB with a maximum of 5 years between administrations and a subsample (n = 24) who had both IQ and CNB assessments at two time points. We estimated domain-level CNB scores using exploratory factor analysis (including bifactor for overall scores) and related those scores (intraclass correlations (ICCs)) to the IQ scores. We found that the overall CNB accuracy score showed similar correlations between time 1 and time 2 as IQ (0.775 for IQ and 0.721 for CNB accuracy), correlated well with the IQ scores (ICC = 0.565 and 0.593 for time 1 and time 2, respectively), and correlated similarly with adaptive functioning (0.165 and 0.172 for IQ and CNB, respectively). We provide a crosswalk (from linear equating) between standardized CNB and IQ scores. Results suggest that one can substitute the CNB for IQ testing in future genetic studies that aim to probe specific domains of brain-behavior relations beyond IQ.

Spinal cord injury: A multisystem physiological impairment/dysfunction

Spinal cord injury (SCI) is a complex disease that affects not only sensory and motor pathways below the neurological level of injury (NLI) but also all the organs and systems situated below this NLI. This multisystem impairment implies comprehensive management in dedicated SCI specialized centers, by interdisciplinary and multidisciplinary teams, able to treat not only the neurological impairment, but also all the systems and organs affected. After a brief history of the Spinal Cord Medicine, the author describes how to determine the level and severity of a SCI based on the International Standards for Neurological Classification of Spinal Cord Injury and the prognosis factors of recovery. This article provides also a review of the numerous SCI-related impairments (except for urinary, sexual problems and pain treated separately in this issue), their principles of management and related complications.

The association between witnessing patient death and mental health outcomes in frontline COVID-19 healthcare workers

BACKGROUND

Healthcare workers (HCW) treating coronavirus disease 2019 (COVID-19) patients face high levels of psychological stress. We aimed to compare mental health outcomes, risk and protective factors for posttraumatic stress symptoms (PTSS), probable depression, and anxiety between HCW working in COVID-19 and non-COVID-19 wards.

METHODS

A self-report survey, administered in a large tertiary hospital in Israel during the peak of the COVID-19 outbreak was completed by 828 HCW (42.2% physicians, 57.8% nurses. Patient-Reported Outcomes Measurement Information System; the Patient Health Questionnaire-9; the Primary Care-Post Traumatic Stress Disorder Screen for DSM-5 (PC-PTSD-5) were used for assessing anxiety, depression, and PTSS, respectively. Pandemic-related stress factors, negative experiences, and potential protective factors were also assessed.

RESULTS

Median PC-PTSD scores differed significantly between study teams (χ² [5] = 17.24; p = .004). Prevalence of probable depression and anxiety were similar in both groups. Risk factors for mental health outcomes included mental exhaustion, anxiety about being infected and infecting family. Overall, higher proportion of the COVID-19 team witnessed patient deaths as compared to the non-COVID-19 team (50.2% vs. 24.7%). Witnessing patient death at the COVID-19 wards was associated with a four-fold increased likelihood of PTSS (odds ratio [OR] = 3.97; 95% confidence interval [CI], 1.58-9.99; p = .0007), compared with the non-COVID-19 wards (OR 0.91; 95% CI, 0.51-1.61; p = .43).

CONCLUSIONS

Witnessing patient death appears to be a risk factor for PTSS unique to HCW directly engaged in treating patients with COVID-19. Our findings suggest that helping HCW cope with COVID-19 related deaths might reduce their risk of posttraumatic stress.

Trajectories of post-traumatic stress symptoms, anxiety, and depression in hospitalized COVID-19 patients: A one-month follow-up

OBJECTIVES

Little is known about the mental health outcomes of hospitalized COVID-19 patients. The aims of the study were: (1) to examine the trajectories of anxiety, depression, and pandemic-related stress factors (PRSF) of COVID-19 hospitalized patients one-month following hospitalization; (2) to assess the presence of post-traumatic stress symptoms (PTSS) a month after hospitalization; (3) to identify baseline risk and protective factors that would predict PTSS one month after hospitalization.

METHODS

We contacted hospitalized COVID-19 patients (n = 64) by phone, at three time-points: during the first days after admission to the hospital (T1); after ~two weeks from the beginning of hospitalization (T2), and one month after hospitalization (T3). At all time-points we assessed the levels of anxiety and depression symptoms, as well as PRSF. At T3, PTSS were assessed.

RESULTS

The levels of depressive and anxiety symptoms decreased one-month following hospitalization. Moreover, higher levels of anxiety (standardized β = 1.15, 95% CI = 0.81-1.49, p < 0.001) and depression (β = 0.97, 95% CI = 0.63-1.31 p < 0.001) symptoms during the first week of hospitalization, feeling socially disconnected (β = 0.59, 95% CI = 0.37-0.81 p < 0.001) and experiencing a longer hospitalization period (β = 0.25, 95% CI = 0.03-0.47 p = 0.026) predicted higher PTSS scores a month post-hospitalization.

CONCLUSIONS

We identified early hospitalization risk factors for the development of PTSS one month after hospitalization that should be targeted to reduce the risk for PTSS.

Delivering Difficult News: Simulation-Enhanced Training Improves Psychiatry Residents' Clinical Communication Skills

Background: Delivering difficult news to individuals diagnosed with mental health disorders and their family members can be challenging. The use of simulated patients (SP) is an effective teaching method to enhance clinical skills, particularly those around communication. We developed, implemented, and evaluated the effectiveness of an SP-based training module to improve psychiatric residents' clinical communication skills in delivering difficult news. Methods: We conducted 5-h workshops consisting of 3 components: (1) a high-fidelity simulation session with a professional actor; (2) a 30-min lecture; and (3) role-playing of 3 short scenarios, during which residents rotated taking on different roles (as psychiatrist, patient, or family member). We observed through a 1-way mirror and videotaped each resident's simulation session and followed it with personalized debriefing. Following the workshop, each resident received the full-length video of their simulated interview, together with a list of questions as a take-home assignment. Two months after the workshop, the residents were invited to a second SP-based session, during which 2 independent evaluators, each a board-certified psychiatrist with expertise in medical simulation, evaluated the participants' communication skills using a previously validated instrument. To avoid observation bias, the 2 evaluators rated the videotapes blind to the timing of the simulation (pre- vs. post-training). Participants completed self-report questionnaires on satisfaction and self-confidence, before, after, and 2 months following the workshop. Findings: Of the 28 psychiatric residents who participated in the training day, 24 (86%) completed the post-workshop evaluation. Mean communication score increased from 24.9 to 27.8 (paired t-test: 5.6, p < 0.001). The mean score for the self-confidence questionnaire, calculated on a 1 to 5 Likert scale, increased from 3.4 to 4.0 after the training day, and remained unchanged (4.2) 2 months later (p < 0.001). Conclusions: An SP-based training module proved useful in improving the objectively measured communication skills of psychiatric residents delivering difficult news. The training further enhanced participants' subjective sense of confidence in those clinical skills.

Temperature-Dependent Spin Transport and Current-Induced Torques in Superconductor-Ferromagnet Heterostructures

We investigate the injection of quasiparticle spin currents into a superconductor via spin pumping from an adjacent ferromagnetic metal layer. To this end, we use NbN-Ni_{80}Fe_{20}(Py) heterostructures with a Pt spin sink layer and excite ferromagnetic resonance in the Permalloy layer by placing the samples onto a coplanar waveguide. A phase sensitive detection of the microwave transmission signal is used to quantitatively extract the inductive coupling strength between the sample and the coplanar waveguide, interpreted in terms of inverse current-induced torques, in our heterostructures as a function of temperature. Below the superconducting transition temperature T_{c}, we observe a suppression of the dampinglike torque generated in the Pt layer by the inverse spin Hall effect, which can be understood by the changes in spin current transport in the superconducting NbN layer. Moreover, below T_{c} we find a large fieldlike current-induced torque.

Observation of Antiferromagnetic Magnon Pseudospin Dynamics and the Hanle Effect

We report on experiments demonstrating coherent control of magnon spin transport and pseudospin dynamics in a thin film of the antiferromagnetic insulator hematite utilizing two Pt strips for all-electrical magnon injection and detection. The measured magnon spin signal at the detector reveals an oscillation of its polarity as a function of the externally applied magnetic field. We quantitatively explain our experiments in terms of diffusive magnon transport and a coherent precession of the magnon pseudospin caused by the easy-plane anisotropy and the Dzyaloshinskii-Moriya interaction. This experimental observation can be viewed as the magnonic analog of the electronic Hanle effect and the Datta-Das transistor, unlocking the high potential of antiferromagnetic magnonics toward the realization of rich electronics-inspired phenomena.

Anxiety and Depression Symptoms in COVID-19 Isolated Patients and in Their Relatives

Background: While focusing on the management and care of COVID-19 patients, the mental health of these patients and their relatives is being overlooked. The aim of the current study was to measure anxiety and depression, and to assess their association with socio-demographic and pandemic-related stress factors in COVID-19 patients and their relatives during the initial stage of hospitalization. Methods: We assessed isolated hospitalized patients (N = 90) and their relatives (adults and children, N = 125) by phone, 25-72 h following patients' admission. The quantitative measures included the Anxiety and Depression modules of the Patient-Reported Outcomes Measurement Information System (PROMIS) and pandemic-related stress factors. Qualitative measures included questions exploring worries, sadness, and coping modes. Results: Both patients and relatives suffer from high levels of anxiety and related pandemic worries, with lower levels of depressive symptoms. Compared to adult relatives, child relatives reported significantly lower anxiety. The multivariable logistic regression analysis revealed an increased risk for anxiety among females and a decreased risk among ultra-orthodox participants. While increased anxiety among patients was associated with feelings of isolation, increased anxiety among relatives was associated with a feeling of not being protected by the hospital. Conclusions: Patients and relatives experience similar high anxiety levels which are more robust in women and lower in ultra-orthodox participants. Our findings indicate that anxiety symptoms of both patients and adult relatives should be addressed.

Anxiety, pandemic-related stress and resilience among physicians during the COVID-19 pandemic

BACKGROUND

Physicians play a crucial frontline role in the COVID-19 pandemic, which may involve high levels of anxiety. We aimed to investigate the association between pandemic-related stress factors (PRSF) and anxiety and to evaluate the potential effect of resilience on anxiety among physicians.

METHODS

A self-report digital survey was completed by 1106 Israeli physicians (564 males and 542 females) during the COVID-19 outbreak. Anxiety was measured by the 8-item version of the Patient-Reported Outcomes Measurement Information System. Resilience was evaluated by the 10-item Connor-Davidson Resilience Scale. Stress was assessed using a PRSF inventory.

RESULTS

Physicians reported high levels of anxiety with a mean score of 59.20 ± 7.95. We found an inverse association between resilience and anxiety. Four salient PRSF (mental exhaustion, anxiety about being infected, anxiety infecting family members, and sleep difficulties) positively associated with anxiety scores.

CONCLUSIONS

Our study identified specific PRSF including workload burden and fear of infection that are associated with increased anxiety and resilience that is associated with reduced anxiety among physicians.

Gestational age and the risk of autism spectrum disorder in Sweden, Finland, and Norway: A cohort study

INTRODUCTION

The complex etiology of autism spectrum disorder (ASD) is still unresolved. Preterm birth (<37 weeks of gestation) and its complications are the leading cause of death of babies in the world, and those who survive often have long-term health problems. Length of gestation, including preterm birth, has been linked to ASD risk, but robust estimates for the whole range of gestational ages (GAs) are lacking. The primary objective of this study was to provide a detailed and robust description of ASD risk across the entire range of GAs while adjusting for sex and size for GA.

METHODS AND FINDINGS

Our study had a multinational cohort design, using population-based data from medical registries in three Nordic countries: Sweden, Finland, and Norway. GA was estimated in whole weeks based on ultrasound. Children were prospectively followed from birth for clinical diagnosis of ASD. Relative risk (RR) of ASD was estimated using log-binomial regression. Analyses were also stratified by sex and by size for GA. The study included 3,526,174 singletons born 1995 to 2015, including 50,816 (1.44%) individuals with ASD. In the whole cohort, 165,845 (4.7%) were born preterm. RR of ASD increased by GA, from 40 to 24 weeks and from 40 to 44 weeks of gestation. The RR of ASD in children born in weeks 22-31, 32-36, and 43-44 compared to weeks 37-42 were estimated at 2.31 (95% confidence interval [CI] 2.15-2.48; 1.67% vs 0.83%; p-value < 0.001), 1.35 (95% CI 1.30-1.40; 1.08% vs 0.83%; p-value < 0.001), and 1.37 (95% CI 1.21-1.54; 1.74% vs 0.83%; p-value < 0.001), respectively. The main limitation of this study is the lack of data on potential causes of pre- or postterm birth. Also, the possibility of residual confounding should be considered.

CONCLUSION

In the current study, we observed that the RR of ASD increased weekly as the date of delivery diverged from 40 weeks, both pre- and postterm, independently of sex and size for GA. Given the unknown etiology of ASD and the lifelong consequences of the disorder, identifying groups of increased risk associated with a potentially modifiable risk factor is important.

Reducing Stigma Toward Psychiatry Among Medical Students: A Multicenter Controlled Trial

Objective

To examine the effect of a novel antistigma intervention curriculum (ASIC) in reducing stigma toward psychiatry among medical students.

Methods

Medical students from 8 hospitals in central Israel were divided into intervention (n = 57) and control (n = 163) arms. The students completed the 30-item Attitudes Toward Psychiatry (ATP-30) and the Attitudes Toward Mental Illness (AMI) scales at psychiatry rotation onset and conclusion. The ASIC was designed to target prejudices and stigma through direct informal encounters with people with serious mental illness (SMI) during periods of remission and recovery. Supervised small-group discussions followed those encounters to facilitate processing of thoughts and emotions that ensued and to discuss salient topics in psychiatry. The study was conducted between November 2017 and July 2018.

Results

Significant between-group differences were found at endpoint for attitudes toward psychiatry and psychiatric patients (P < .001). Although changing attitudes toward psychiatry as a career choice was not part of the ASIC, a significant between-group difference emerged by endpoint (P < .001).

Conclusions

Implementation of an ASIC that includes contact with individuals with lived SMI experience followed by supervised small-group discussions is effective in reducing stigma in medical students' perceptions of people with mental illness and psychiatry. Further evaluation is warranted with regard to the long-term destigmatizing effects of an ASIC.

Trial Registration

ClinicalTrials.gov identifier: NCT03907696.

Single-Day Simulation-Based Training Improves Communication and Psychiatric Skills of Medical Students

BACKGROUND

Use of standardized (or simulated) patients (SP) is considered an effective teaching method for improving clinical and communication skills. This study assesses the effect of a single-day simulated patients (SP)-based training course on medical students' communication and basic skills in clinical psychiatry during their psychiatry rotation in a university-affiliated tertiary medical center.

METHODS

Forty-two third-year medical students participated. Communication and basic skills in clinical psychiatry were evaluated by a modified Four Habits Coding Scale (4HCS) and the psychiatric interview coding scale before and after SP training. An actual patient interview by the students 1 week after the training was evaluated by an attending psychiatrist blinded to the student's score during the SP-based training. Self-report questionnaires on satisfaction from the training and its impact on their self-confidence were administered at the end of training.

FINDINGS

The mean pre-training 4HCS score of 33.9 increased to 52.3 post-training (p < 0.001). The mean psychiatric interview coding scale score increased from 4.33 to 5.36 (p = 0.002). The self-report questionnaire yielded a mean score of 4.21 on a 1-5 Likert scale, implying high levels of satisfaction and self-confidence.

CONCLUSIONS

A single SP-based training course of medical students sufficed to improve clinical and communication skills in psychiatric settings and enhance their subjective perception of those skills.

The Association Between Prenatal Exposure to Antidepressants and Autism: Some Research and Public Health Aspects

Use of antidepressants (ADs) in general, and in pregnant notwithstanding, has been increasing globally in recent decades. Associations with a wide range of adverse perinatal and childhood outcomes following prenatal ADs exposure have been observed in registry-based studies, with Autism Spectrum Disorders (ASD) frequently reported. Studies using animal models, sibling analyses, and negative control approaches, have linked dysfunctional serotonin metabolism with ASD, but did not convincingly tease apart the role of maternal mental health from that of ADs. As work to decipher the nature of the AD-ASD association continues, this review raises some public health concerns pertinent to a hypothetical conclusion that this association is causal, including the need to identify specific gestation periods with higher risk, the importance of precise assessment of the ASD potential prevention that might be attributed to AD discontinuation, and the estimation of risks associated with prenatal exposure to untreated depression.

Spin Transport in a Magnetic Insulator with Zero Effective Damping

Applications based on spin currents strongly rely on the control and reduction of their effective damping and their transport properties. We here experimentally observe magnon mediated transport of spin (angular) momentum through a 13.4-nm thin yttrium iron garnet film with full control of the magnetic damping via spin-orbit torque. Above a critical spin-orbit torque, the fully compensated damping manifests itself as an increase of magnon conductivity by almost 2 orders of magnitude. We compare our results to theoretical expectations based on recently predicted current induced magnon condensates and discuss other possible origins of the observed critical behavior.

[THE ASSOCIATION BETWEEN EXPOSURE TO TRAUMA AND MENTAL ILLNESS AMONG WORK MIGRANTS AND ASYLUM SEEKERS IN ISRAEL: A SURVEY AT THE OPEN CLINIC, PHYSICIANS FOR HUMAN RIGHTS, 2012-2013]

INTRODUCTION

In 2012, 183,896 work migrants and 47,704 asylum-seekers and work-migrants arrived in Israel. These populations are at high-risk for depression, anxiety and posttraumatic stress disorder (PTSD). The Open Clinic of Physicians for Human Rights (PHR) delivers free medical and mental health services to these individuals.

AIMS

To evaluate exposure to traumatic events, and compare the prevalence and risk for PTSD, depression and anxiety symptoms between work-migrants and asylum-seekers.

METHODS

An analytical cross-sectional study of adults visiting the Open Clinic was conducted. Participants completed self-report questionnaires including information on demographics and exposure to traumas, depression, anxiety and PTSD. Statistical models were constructed to predict outcome variables of PTSD, depression and anxiety as dichotomist variables using a logistic regression, and association odds ratio (OR) and confidence interval (CI) on 95% level.

RESULTS

There were 241 participants; 165 asylum-seekers, 76 work-migrants. Work-migrants were exposed to more traumatic events. A total of 17-31% met PTSD criteria. Significantly more asylum-seekers met PTSD criteria. A total of 43%-50% met criteria for depression and/or anxiety, with no between-group differences. Significant association was found between immigration status and PTSD risk. Exposure to traumatic events was significantly associated with the prediction of PTSD, depression and anxiety.

DISCUSSION

Exposure to traumatic events was high among the Open Clinic service users, specifically work-migrants. Prevalence and risk for post-traumatic symptoms were significantly higher among asylum-seekers. It is important to conduct further research, in order to characterize risk and resilience factors in this excluded population, and to plan language and culture-competent mental health services.

Secure quantum remote state preparation of squeezed microwave states

Quantum communication protocols based on nonclassical correlations can be more efficient than known classical methods and offer intrinsic security over direct state transfer. In particular, remote state preparation aims at the creation of a desired and known quantum state at a remote location using classical communication and quantum entanglement. We present an experimental realization of deterministic continuous-variable remote state preparation in the microwave regime over a distance of 35 cm. By employing propagating two-mode squeezed microwave states and feedforward, we achieve the remote preparation of squeezed states with up to 1.6 dB of squeezing below the vacuum level. Finally, security of remote state preparation is investigated by using the concept of the one-time pad and measuring the von Neumann entropies. We find nearly identical values for the entropy of the remotely prepared state and the respective conditional entropy given the classically communicated information and, thus, demonstrate close-to-perfect security.

Continuous-variable remote state preparation in the microwave domain would allow to leverage the superconducting technology for quantum networks applications. Here, the authors show how to deterministically prepare squeezed Gaussian states across 35 cm using previously shared entanglement.

(Blut-)Gerinnung und Wundverschluß bei Invertebraten

Außer der Tatsache, daß in allen beschriebenen Tierstämmen Zellen entweder allein oder zusammen mit einem Plasmabestandteil „Gerinnsel” bilden, gibt es keinen Befund zur Gerinnung oder Blutstillung bei Invertebraten, der in allen Stämmen und Klassen übereinstimmend erhoben wurde. Neben der Subjektivität in der Darstellung und Beurteilung (z. B. mikroskopischer Befunde), dem Zustand und Entwicklungsstadium der Versuchstiere und dem verschieden schnellen Ablauf der Gerinnungserscheinungen haben sicherlich die jeweils angewandten Methoden der Blutentnahme und Untersuchung in entscheidendem Maße die Versuchsergebnisse beeinflußt. Bei einer größeren Zahl von Arbeiten handelt es sich nur um die Beschreibung makroskopisch erkennbarer Veränderungen nach Austritt des Blutes bzw. der Körperflüssigkeit. In der Mehrzahl sind die Darstellungen der Gerinnungsverhältnisse aus mikroskopischen Beobachtungen gewonnen, die sich aber in der Technik weitgehend unterscheiden. Beobachtungen eines Bluttropfens auf dem Objektträger, eines hängenden Tropfens (auch in einer feuchten Kammer), eines Blutfilms unter dem Deckglas und eines Bluttropfens, der in Öl eingetaucht ist, sind die am häufigsten angewandten mikroskopischen Untersuchungen, für die das Lichtmikroskop, das Phasenkontrastmikroskop und in einem Fall [Franke (1960)] das Elektronenmikroskop herangezogen wurden. Auf den Einfluß der Methodik auf die Versuchsergebnisse wurde von einigen Autoren immer wieder hingewiesen, zuletzt von Franke (1960), der ein eindrucksvolles Beispiel (Einfluß des pH-Wertes) gibt. Untersuchungsmethoden, die denen der Gerinnungsforschung an Säugetieren entsprechen, wurden bzw. konnten nur bei Arthropoden — und hier wiederum vorwiegend bei Crustaceen — angewandt werden. Die letzteren weisen nicht nur „Gerinnung” eines Plasmabestandteils, sondern vor allem auch ausreichende Blutmengen für solche Untersuchungen auf. Die Blutentnahme bei großen Crustaceen ist relativ leicht, wogegen bei Insekten winzige Ausbeuten und ein intensiver Kontakt mit Wundrändern und fremden Oberflächen nicht zu vermeiden sind. Da eine der wichtigsten Möglichkeiten, den Gerinnungsvorgang zu analysieren, in der Zugabe von Substanzen besteht, deren Wirkung und Eigenschaften bekannt sind (z. B. Inhibitoren der Gerinnung), besteht bei der oft rasch eintretenden Gerinnselbildung die Gefahr, daß zu dem Zeitpunkt, an dem Blut und die zu testenden Substanzen zusammenkommen, die Zell- und Plasmaveränderungen schon so weit fortgeschritten sind, daß eine sichere Beeinflussung nicht mehr zustande kommt.

Birth seasonality and risk of autism spectrum disorder

Season of birth has been hypothesized to be a risk factor for autism spectrum disorder (ASD). However, the evidence has been mixed and limited due to methodological challenges. We examine ASD birth trends for 5,464,628 births across 5 countries. ASD birth prevalence data were obtained from the International Collaboration for Autism Registry Epidemiology database, including children born in Denmark, Finland, Norway, Sweden, and Western Australia. Empirical mode decomposition and cosinor modeling were used to assess seasonality. We show seasonal variation in ASD births for the countries of Finland and Sweden. There was a modest increase in risk for children born in the fall and a modest decrease in risk for children born in the spring. Solar radiation levels around conception and the postnatal period were inversely correlated with seasonal trends in ASD risk. In the first multinational study of birth seasonality of ASD, there was evidence supporting the presence of seasonal trends in Finland and Sweden. The observations that risk was highest for fall births (i.e., conceived in the winter) and lowest for spring births (i.e., conceived in the summer), and sunlight levels during critical neurodevelopmental periods explained much of the seasonal trends, are consistent with the hypothesis that a seasonally fluctuating risk factor may influence risk of ASD.

Getting more out of meta-analyses: a new approach to meta-analysis in light of unexplained heterogeneity

BACKGROUND AND OBJECTIVES

Meta-analyses sometimes summarize results in the presence of substantial unexplained between-study heterogeneity. As GRADE criteria highlight, unexplained heterogeneity reduces certainty in the evidence, resulting in limited confidence in average effect estimates. The aim of this paper is to provide a new clinically useful approach to estimating an intervention effect in light of unexplained heterogeneity.

METHODS

We used a random-effects model to estimate the distribution of an intervention-effect across various groups of patients given data derived from meta-analysis. The model provides a distribution of the probabilities of various possible effects in a new group of patients. We examined how our method influenced the conclusions of two meta-analyses.

RESULTS

In one example, our method illustrated that evidence from a meta-analysis did not support authors' highly publicized conclusion that hypericum is as effective as other antidepressants. In the second example, our method provided insight into a subgroup analysis of the effect of ribavirin in hepatitis C, demonstrating clear important benefit in one subgroup but not in others.

CONCLUSION

Analysing the distribution of an intervention-effect in random-effects models may enable clinicians to improve their understanding of the probability of particular-intervention effects in a new population.

Medial temporal lobe functional connectivity predicts stimulation-induced theta power

Focal electrical stimulation of the brain incites a cascade of neural activity that propagates from the stimulated region to both nearby and remote areas, offering the potential to control the activity of brain networks. Understanding how exogenous electrical signals perturb such networks in humans is key to its clinical translation. To investigate this, we applied electrical stimulation to subregions of the medial temporal lobe in 26 neurosurgical patients fitted with indwelling electrodes. Networks of low-frequency (5–13 Hz) spectral coherence predicted stimulation-evoked increases in theta (5–8 Hz) power, particularly when stimulation was applied in or adjacent to white matter. Stimulation tended to decrease power in the high-frequency broadband (HFB; 50–200 Hz) range, and these modulations were correlated with HFB-based networks in a subset of subjects. Our results demonstrate that functional connectivity is predictive of causal changes in the brain, capturing evoked activity across brain regions and frequency bands.

Direct electrical brain stimulation can induce widespread changes in neural activity, offering a means to modulate network-wide activity and treat disease. Here, the authors show that the low-frequency functional connectivity profile of a stimulation target predicts where induced theta activity occurs.

Apgar score and risk of autism

Low Apgar score has been associated with higher risk for several neurological and psychiatric disorders, including cerebral palsy and intellectual disability. Studies of the association between Apgar score and autism spectrum disorder (ASD) have been inconsistent. We aimed to investigate (1) the association between low Apgar score at 5 min and risk for ASD, and (2) the modifying effects of gestational age and sex on this association in the largest multinational database of ASD. We included prospective data from 5.5 million individuals and over 33,000 cases of ASD from Norway, Sweden, Denmark and Western Australia who were born between 1984 and 2007. We calculated crude and adjusted risk ratios (RR) with 95% confidence intervals (95% CIs) for the associations between low Apgar score and ASD. All analyses for ASD were repeated for autistic disorder (AD). We used interaction terms and stratified analysis to investigate the effects of sex, gestational age, and birth weight on the association. In fully adjusted models, low Apgar scores (1–3) (RR, 1.42; 95% CI, 1.16–1.74), and intermediate Apgar scores (4–6) (RR, 1.50; 95% CI, 1.36–1.65) were associated with a higher RR of ASD than optimal Apgar score (7–10). The point estimates for low (RR, 1.88; 95% CI, 1.41–2.51) and intermediate Apgar score (RR, 1.54; 95% CI, 1.32–1.81) were larger for AD than for ASD. This study suggests that low Apgar score is associated with higher risk of ASD, and in particular AD. We did not observe any major modifying effects of gestational age and sex, although there seems to be substantial confounding by gestational age and birth weight on the observed association.

Impact of Chemotherapy Stock-Out on Standard Therapy Delivery Among Cancer Patients in Botswana

Background: Cancer drug shortages represent a complex global issue with potentially adverse survival outcomes. Up to 98% of oncologists and pharmacists surveyed in North America reported at least 1 drug shortage in the prior year and 66% reported at least one patient who had clinical care impacted by the shortage. In low- and middle-income countries (LMICs), these shortages are even more frequent. No studies to our knowledge have evaluated the impact of chemotherapy stock-out on receipt of standard cancer therapy in LMICs. Aim: Quantify the association between the duration of chemotherapy stock-out and the risk of having a suboptimal therapy delivery event, compared with standard delivery of therapy among cancer patients in Botswana. Methods: Prevalent cohort study of patients with cervical, breast, prostate, esophagus, Kaposi sarcoma, head and neck cancers, lung, uterine, ovarian and colorectal cancers who received any systemic therapy between 01/01/16-12/31/16 at Princess Marina Hospital, Botswana. Primary exposure was stock-out duration per cycle interval calculated by generating a code for the six different patterns for chemotherapy stock-out, using stock data at the Central Medical Stores. Primary outcome was suboptimal therapy delivery defined as a dose reduction, dose delay or switch in intended therapy. We measured statistical associations using two sample t-test and mixed effects univariate and multivariate logistic regression models. Results: 378 patients were identified who met diagnostic criteria and received systemic chemotherapy in 2016. Of these, 293 received commonly prescribed standard regimens who contributed 1452 cycle intervals and were included in our analysis. Majority of the patients (48%) had breast cancer. The mean duration of stock-out for receipt of standard therapy without events was 3.2 days (95% CI: 2.8-3.7) compared with 7.8 days for patients who had a suboptimal therapy delivery event (95% CI: 6.6-9) ( P < 0.0001). Male sex, age < 65 and HIV-positive status were also significantly associated with an increased risk of experiencing dose reduction, change in therapy or switch in therapy. Adjusting for these factors in a mixed effects logistic regression, each week of stock-out was independently associated with an 80% increased risk of having a suboptimal therapy delivery event (OR=1.8 (95% CI: 1.6-2.0, P < 0.0001)). Conclusion: Chemotherapy stock-out is independently associated with an 80% increased risk of a patient experiencing dose reduction, change in therapy or delay in therapy. The risk increases with longer duration of stock out. Given prior data showing that these events lead to worse survival outcomes, our further analysis is focusing on quantifying risk of stock-out on survival outcomes in this population. to determine whether interventions promoting standard therapy delivery are warranted to optimize survival outcomes.

Parity-Engineered Light-Matter Interaction

The concept of parity describes the inversion symmetry of a system and is of fundamental relevance in the standard model, quantum information processing, and field theory. In quantum electrodynamics, parity is conserved and large field gradients are required to engineer the parity of the light-matter interaction operator. In this work, we engineer a potassiumlike artificial atom represented by a specifically designed superconducting flux qubit. We control the wave function parity of the artificial atom with an effective orbital momentum provided by a resonator. By irradiating the artificial atom with spatially shaped microwave fields, we select the interaction parity in situ. In this way, we observe dipole and quadrupole selection rules for single state transitions and induce transparency via longitudinal coupling. Our work advances the design of tunable artificial multilevel atoms to a new level, which is particularly promising with respect to quantum chemistry simulations with near-term superconducting circuits.

Quantitative Determination of the Amino Acids and other Ninhydrin Positive Substances in Normal Human Platelets

In normal human platelets twenty amino acids and additionally taurine, phosphoethanolamine and phosphoserine were determined on a quantitative basis, using elution chromatography on ion exchangers.

The highest molar share goes to taurine, glutamic acid, alanine, aspartic acid, proline and serine. The other amino acids can be found in free form only in a low concentration in platelets.

The connection of these results with other investigations on the metabolism is discussed.

The Significance of Malate Dehydrogenase Isoenzymes in Human Blood Platelets

Two MDH isoenzymes were detected in the homogenate of normal human blood platelets. According to their properties the cationic isoenzyme is compartmentalized in the mitochondria, the anionic one belongs to the cytoplasma. In spite of the few mitochondria in human blood platelets the proportion of the cationic enzyme is relatively high.

Both of these enzymes could belong to a transfer system for malate transport across the mitochondrial membrane. As human blood platelets do not contain creatine phosphate a system like that could be of significance for platelet function.

The Differentiation of Acid Phosphatases of Human Blood Platelets

The Acid Phosphatase was tested in human platelets and in the rat liver mitochondrial-lysosomal fraction with p-nitrophenylphosphate and β-glycerophosphate as substrates. In the platelets the following differences were found between the hydrolysis of these two substrates, whereas in rat liver no such differences were observed. 1. The relative rates of hydrolysis and the pH optima for both substrates are different (pH 4.6 for the β-glycerophosphatase, pH 6.0 for the p-nitrophenylphosphatase in the platelets). 2. The p-nitrophenylphosphatase of the platelets is inhibited by p-chlormercuribenzoate and N-ethylmaleimide, but not by fluoride or L + tartrate, whereas the contrary is true for the platelet β-glycerophosphatase and the rat liver activities. 3. The platelet p-nitrophenylphosphatase is rapidly inactivated by preincubation at 40-45° C for 15 min, the other phosphatases are much more heat-resistant. 4. Sucrose density gradient centrifugation of platelet homgenates showed a separation of the two platelet phosphatase activities, the p-nitrophenylphosphatase with its maximum at lower densities than the β-glycerophosphatase.

It is concluded that in human platelets there are at least two different Acid Phosphatases. The β-glycerophosphatase probably represents the lysosomal (as compared to the rat liver enzyme) phosphatase whereas the p-nitrophenylphosphatase of the platelets is a different enzyme whose subcellular localization and functions are as yet unknown.

Localization of Inhibition of Platelet Aggregation by Incubation of Platelet Rich EDTA-Plasma at 37°C

By photometric and microscopic technics investigations have been carried out to determine the nature of the inhibition of platelet aggregation caused by incubating platelet rich EDTA-plasma at 37° C. The results clearly indicate that the inhibition must arise from alterations in the platelets themselves. The appearance of an inhibitory substance in plasma and the release of such a substance from the platelets into the plasma have been excluded. Addition of ADP to the inhibited platelets did not influence the inhibition of platelet aggregation.

Untersuchungen über den In-vitro-Einfluß der kationischen Polypeptide Protaminsulfat und Trasylol auf Aggregation und Retraktion menschlicher Blutplättchen

Basische Polypeptide wie Polylysin, Protaminsulfat, Trasylol oder Lysozym können konzentrationsabhängig die Blutplättchenaggregation auslösen. Die Reaktion läuft im 2,7 mmol EDTA-Plasma ebenso wie in synthetischen Medien ab, ist also offenbar von der Anwesenheit zweiwertiger Kationen oder plasmatischer Kofaktoren weitgehend unabhängig. Eine Temperaturabhängigkeit ließ sich zwischen 4 und 37° C nicht feststellen, trotzdem konnten wir Stoffwechselsteigerungen in den aggregieren-den Plättchen nachweisen, die nach Art und Ausmaß etwa den durch Ca++- oder Mg++-auslösbaren Veränderungen entsprachen. Die Befunde könnten die bei der Heparinneutralisierung nach extrakorporaler Zirkulation in Form von Thrombo-embolien oder verstärkter Blutungsneigung auftretenden Komplikationen erklären.

Chromatographic Isolation of the LDH-Isoenzymes of Human Blood Platelets and an Investigation of Their Enzyme Kinetics

The LDH-isoenzymes of human blood platelets show a distinct predominance of the isoenzymes 2 and 3 upon chromatography on DEAE-cellulose. Small amounts of LDH-1 are also present, while only traces of LDH-4 and -5 can be detected.

Enzyme kinetic investigations of the principal isoenzymes LDH-1, -2 and -3 clearly show that the differences in inhibition constants with pyruvate as substrate which are demonstrable at 25° largely disappear at 37°. On the other hand, the differences among the isoenzymes in their affinity for pyruvate and lactate as substrate as well as in with respect to the optimal substrate concentrations of pyruvate are more marked at 37° than at 25°. Also, the type of inhibition found with lactate as substrate is increasingly the expression of a higher order reaction in going from LDH-1 to LDH-3. A dependence of the LDH distribution pattern upon the metabolism of the cell is discussed. A comparison of our results with thrombocytes with those of other workers with erythrocytes and leucocytes makes it unlikely that the LDH pattern is directly dependent upon the existence of an oxidative metabolism. Rather, the redox potential of the cell could be of importance for the nature of the pattern of isoenzymes and for their differing kinetic properties.

Untersuchungen über das Verteilungsmuster der Laktatdehydrogenase-Isoenzyme menschlicher Blutplättchen

Mit Hilfe der Polyacrylamid-Disc-Elektrophorese wurde das LDH-Isoenzymver-teilungsmuster normaler menschlicher Blutplättchen untersucht und eine Verteilung mit starkem Überwiegen der Banden 2 und 3 bei deutlich geringerem Anteil der LDH-1 gefunden. LDH-4 konnte nur in Spuren, LDH-5 in diesem System nicht nachgewiesen werden. Folgende Anteile wurden für die einzelnen Isoenzyme bestimmt (x ± s, n = 16): LDH-1 = 9,8 ± 7,3, LDH-2 =50,7 ± 7,7, LDH-3 = 38,3 ± 7,5, LDH-4 = 1,2 ± 1,2 rel. %.

Über den Energiestoffwechsel normaler menschlicher Thrombozyten

Es wurden in ungewaschenen und mehrfach gewaschenen Thrombozyten quantitativ folgende Fermente der Glykolyse, des Pentosephosphat- und Zitronensäurezyklus, der Atmungskette, der Phosphatspaltung und der Transaminie-rungen bestimmt:

Hexokinase, Diphosphofruktosealdolase, Trioseisomerase, L-a-Glycerophos-phatdehydrogenase, Phosphoglyceraldehydrogenase, 3-Phosphoglycerat-l -Kinase, Enolase, Pyruvatkinase, Milchsäuredehydrogenase, Glukose-6-Phosphatdehydro-genase, 6-Phosphoglukonatdehydrogenase, TPNH-Oxydase, Isozitronensäure-dehydrogenase, Succinodehydrogenase, Äpfelsäuredehydrogenase, globale Atmungskettenbestimmung, Myokinase, Mg++-aktivierte ATPase, Ca++-aktivierte ATPase, alkalische Phosphatase, Glutamat-Oxalacetat-Transaminase, Glutamat-Pyruvat-Transaminase.

Außerdem wurden an ungewaschenen und mehrfach gewaschenen Blutplättchen Gesamtstoffwechselmessungen sowie Bestimmungen von Intermediär- und Endprodukten des Stoffwechsels vorgenommen, wie Glukoseverbrauch, Milchsäurebildung, Pyruvatbildung, CO2-Bildung, O2-Verbrauch, zusätzlich Bestimmungen der energiereichen Phosphate ATP, ADP und AMP.

Folgende Ergebnisse wurden erhalten:

1. Die Blutplättchen enthalten die vollständigen Stoffwechselketten der Glykolyse, des Pentosephosphat- und Zitronensäurezyklus, die Atmungskette, 3 ATP-spaltende Fermente und Transaminasen.

2. Der Gehalt an glykolytischen Enzymen übersteigt bei weitem den Gehalt an Enzymen des oxydativen Kohlenhydratabbaues.

3. Die begrenzende Reaktion der Glykolyse in den Thrombozyten ist die Hexokinase-Reaktion.

4. Der Stoffwechsel der Blutplättchen im Vergleich zu anderen Zellelementen ist groß.

5. Auch unter aeroben Bedingungen wird über die Hälfte der abgebauten Glukose zu Pyruvat und Laktat glykolysiert; nur etwa 1/5 der Glukose wird zu CO2 und H2O verbrannt. ¼ der abgebauten Glukose wurde in den Stoffwechselendprodukten nicht wiedergefunden; es wird angenommen, daß sie zu Glykogen, Aminosäuren und Lipiden metabolisiert wird.

6. Der respiratorische Quotient (R.Q.) der Thrombozyten beträgt 1,1, was für einen vorwiegenden Kohlenhydratstoffwechsel spricht.

7. Der ATP-Gehalt der Blutplättchen ist auffallend hoch und liegt etwa 150mal höher als der ATP-Gehalt der Erythrozyten, bezogen auf das Gesamtprotein der Zellen. Das Verhältnis von ATP : AMP : ADP betrug bei unseren Messungen 3,1 : 2,3 : 1 und liegt damit in der Größenordnung anderer Organe. Dieser Befund spricht dafür, daß bei unseren Versuchsbedingungen die Plättchen nicht geschädigt wurden.

8. Unter dem Einfluß von 1 bis 3 Thrombozytenwaschungen kommt es zu einem weitgehenden Verlust der meisten für den Energiehaushalt wichtigen Enzyme, besonders der phosphatgruppenübertragenden Fermente 3-Phospho-glycerat-1-Kinase und Pyruvatkinase mit der Folge eines starken ATP-Verlustes der Plättchen. Der Zellstoffwechsel wird durch Plättchenwaschungen deutlich beeinträchtigt.

9. Enzym- und Stoffwechseluntersuchungen sollten wegen ihrer Beeinträchtigung durch Thrombozytenwaschungen möglichst an vom Plasma abgetrennten, ungewaschenen Blutplättchen durchgeführt werden. Vergleichende Untersuchungen an Plasmaenzymen zeigten, daß die Meßfehler durch anhaftende Plasmafermente unbedeutend sind und nur etwa 1 bis 10% ausmachen.

10. Eine direkte Abhängigkeit der Retraktionsfähigkeit der Blutplättchen von ihrem Energiestoffwechsel konnte durch Hemmversuche der ATP-liefernden Reaktionen der Glykolyse wahrscheinlich gemacht werden. Bei normaler oder erhöhter Thrombozytenzahl führen 1 bis 3 Waschungen zu einer eben noch erkennbaren Störung der Retraktion, die bei suboptimaler Thrombozytenkonzen-tration deutlicher wird.

11. Vergleichende Untersuchungen über die Enzymverteilungsmuster und die Berechnung der Anteile der einzelnen Enzymproteine am Gesamtprotein der Zellen weisen auf Ähnlichkeiten zwischen dem Stoffwechsel von Skelettmuskulatur und Thrombozyten hin. Beiden Zellelementen ist die Fähigkeit zu mechanischer Arbeit gemeinsam.