Real-time measurements of ATP dynamics via ATeams in Plasmodium falciparum reveal drug-class-specific response patterns.

Malaria tropica, caused by the parasite Plasmodium falciparum (P. falciparum), remains one of the greatest public health burdens for humankind. Due to its pivotal role in parasite survival, the energy metabolism of P. falciparum is an interesting target for drug design. To this end, analysis of the central metabolite adenosine triphosphate (ATP) is of great interest. So far, only cell-disruptive or intensiometric ATP assays have been available in this system, with various drawbacks for mechanistic interpretation and partly inconsistent results. To address this, we have established fluorescent probes, based on Förster resonance energy transfer (FRET) and known as ATeam, for use in blood-stage parasites. ATeams are capable of measuring MgATP2- levels in a ratiometric manner, thereby facilitating in cellulo measurements of ATP dynamics in real-time using fluorescence microscopy and plate reader detection and overcoming many of the obstacles of established ATP analysis methods. Additionally, we established a superfolder variant of the ratiometric pH sensor pHluorin (sfpHluorin) in P. falciparum to monitor pH homeostasis and control for pH fluctuations, which may affect ATeam measurements. We characterized recombinant ATeam and sfpHluorin protein in vitro and stably integrated the sensors into the genome of the P. falciparum NF54attB cell line. Using these new tools, we found distinct sensor response patterns caused by several different drug classes. Arylamino alcohols increased and redox cyclers decreased ATP; doxycycline caused first-cycle cytosol alkalization; and 4-aminoquinolines caused aberrant proteolysis. Our results open up a completely new perspective on drugs' mode of action, with possible implications for target identification and drug development.

Autonomic regulation and comorbid symptoms in children with attention deficit hyperactivity disorder.

OBJECTIVE: Vagally-mediated heart rate variability (vmHRV) is regarded as transdiagnostic marker of emotion regulation and cognitive control capacity. We analysed vmHRV of children with attention deficit/hyperactivity disorder (ADHD). Based on previous research, we expected to find comorbid symptom dimensions (i.e. internalizing symptoms, conduct problems (CP), and callous unemotional (CU) traits) to relate to vmHRV measures. METHODS: The sample comprised 100 (70 boys) medication naïve children with ADHD. Children were 6 to 11 years old. High frequency HRV (HF-HRV) was measured at rest and during a delay of gratification task. Additionally, sympathetic reactivity was assessed via skin conductance responses (SCR). Comorbid symptoms were assessed by parent-report questionnaires and clinical interviews. RESULTS: The multiple correlation between CU traits and the HF-HRV scores proved statistically significant. Higher CU traits were associated with higher HRV resting-state and response scores. CP were positively associated with the SCR score. CONCLUSION: In children with ADHD, increased CU traits might point to a comparatively less impaired self-regulation capacity in the reward-related context. The result corresponds to findings from previous studies. In the future, CU traits should be considered in analyses of autonomic regulation in ADHD.

Premorbid body weight predicts weight loss in both anorexia nervosa and atypical anorexia nervosa: Further support for a single underlying disorder.

OBJECTIVE: For adolescents, DSM-5 differentiates anorexia nervosa (AN) and atypical AN with the 5th BMI-centile-for-age. We hypothesized that the diagnostic weight cut-off yields (i) lower weight loss in atypical AN and (ii) discrepant premorbid BMI distributions between the two disorders. Prior studies demonstrate that premorbid BMI predicts admission BMI and weight loss in patients with AN. We explore these relationships in atypical AN. METHOD: Based on admission BMI-centile < or ≥5th, participants included 411 female adolescent inpatients with AN and 49 with atypical AN from our registry study. Regression analysis and t-tests statistically addressed our hypotheses and exploratory correlation analyses compared interrelationships between weight loss, admission BMI, and premorbid BMI in both disorders. RESULTS: Weight loss in atypical AN was 5.6 kg lower than in AN upon adjustment for admission age, admission height, premorbid weight and duration of illness. Premorbid BMI-standard deviation scores differed by almost one between both disorders. Premorbid BMI and weight loss were strongly correlated in both AN and atypical AN. DISCUSSION: Whereas the weight cut-off induces discrepancies in premorbid weight and adjusted weight loss, AN and atypical AN overall share strong weight-specific interrelationships that merit etiological consideration. Epidemiological and genetic associations between AN and low body weight may reflect a skewed premorbid BMI distribution. In combination with prior findings for similar psychological and medical characteristics in AN and atypical AN, our findings support a homogenous illness conceptualization. We propose that diagnostic subcategorization based on premorbid BMI, rather than admission BMI, may improve clinical validity. PUBLIC SIGNIFICANCE: Because body weights of patients with AN must drop below the 5th BMI-centile per DSM-5, they will inherently require greater weight loss than their counterparts with atypical AN of the same sex, age, height and premorbid weight. Indeed, patients with atypical AN had a 5.6 kg lower weight loss after controlling for these variables. In comparison to the reference population, we found a lower and higher mean premorbid weight in patients with AN and atypical AN, respectively. Considering previous psychological and medical comparisons showing little differences between AN and atypical AN, we view a single disorder as the most parsimonious explanation. Etiological models need to particularly account for the strong relationship between weight loss and premorbid body weight.

Long-term cortisol secretion in attention deficit hyperactivity disorder: roles of sex, comorbidity, and symptom presentation.

Low activity of the hypothalamic-pituitary-adrenal axis (HPAA) has been found in children with attention deficit hyperactivity disorder (ADHD). The condition may be related to the reduced attention regulation capacity and/or to comorbid oppositional defiant or conduct disorder (ODD/CD). Sex differences are probable but not sufficiently studied. We analyzed the HPAA activity and sympathetic nervous system reactivity (SR) in children with ADHD while accounting for ADHD symptom presentation, comorbidity, and sex differences. The sample comprised 205 children, 98 (61 boys, 37 girls) with ADHD and 107 (48 boys, 59 girls) healthy controls. DSM-5 phenotypic symptom presentation and comorbid ODD/CD were assessed using clinical interviews. Hair cortisol concentration (HCC) was used to assess the long-term, cumulative activity of the HPAA. SR was assessed via skin conductance response (SCR). For control purposes, comorbid internalizing symptoms and indicators of adverse childhood experiences (ACE) were assessed. Children were medication naive. Boys presenting with predominantly inattentive symptoms (ADHD-I) showed lower HCC than healthy boys. Girls presenting with combined symptoms (ADHD-C) showed higher HCC than did healthy girls (p's < 0.05, sex-by-group interaction, F (2,194) = 4.09, p = 0.018). Boys with ADHD plus ODD/CD showed a blunted SR (p < 0.001, sex-by-group interaction, F (2,172) = 3.08, p = 0.048). Adjustment for ACE indicators led to non-significant differences in HCC but did not affect differences in SR. HCC constitutes an easily assessable, reliable, and valid marker of phenotypic ADHD-related features (i.e. symptom presentation and comorbidity). It indicates more homogenous subgroups of ADHD and might point to specifically involved pathophysiological processes.

An examination of sociodemographic and clinical factors influencing help-seeking attitudes and behaviors among adolescents with mental health problems.

This study investigated sociodemographic and clinical factors influencing help-seeking attitudes and behavior among adolescents with mental health problems. As part of the ProHEAD ("Promoting Help-seeking using E-technology for ADolescents") consortium a school-based, online assessment of sociodemographic information, psychopathology, risk-taking and self-harming behavior, help-seeking attitudes and behavior, and barriers to help-seeking was conducted in adolescents aged ≥ 12 years recruited from randomly selected schools in five regions of Germany. Linear regression analyses with the LMG formula were performed to explore predictors of help-seeking attitudes and behavior and assess their relative importance. Nine thousand five hundred and nine participants (95.5%) completed the online assessment (mean age: 15.1 years, 58.6% female). In total, 1606 participants (16.9%) showed relevant mental health problems (e.g., depressive and eating disorder symptoms, alcohol problems, and thoughts of self-harming behavior). Among them, 895 (55.7%) reported having sought help (lifetime), with higher rates for informal (n = 842, 52.4%) compared to professional (n = 380, 23.7%) sources. High help-seeking propensity emerged as the most important factor contributing to professional help-seeking, followed by elevated levels of psychopathology and perceived barriers, with sociodemographic factors being less impactful. Psychopathological severity also outweighed sociodemographic factors in predicting negative help-seeking attitudes. These findings indicate that attitudes towards seeking professional help, perceived barriers, and psychopathology severity critically influence limited adolescent help-seeking behavior. This emphasizes the need for initiatives that promote help-seeking, reduce negative attitudes, and address structural barriers in adolescent mental health care.

The impact of the COVID-19 pandemic on administrative eating disorder prevalence in the outpatient sector and on severity of anorexia nervosa.

The COVID-19 pandemic appears to have had a considerable impact on the mental health of children and adolescents, particularly regarding eating disorders. However, it remains unclear whether the pandemic affected only the frequency or also the severity of eating disorders. We examined potential pandemic-related changes in the administrative prevalence of eating disorders in the outpatient sector compared with other mental disorders using German statutory health insurance data for the age group 10 to 16 years. We also examined disorder severity of anorexia nervosa using data from the multicenter German Registry of Children and Adolescents with Anorexia Nervosa in the same age group. Our results showed a marked increase in the administrative prevalence of eating disorders (based on documented diagnoses) in the outpatient sector among girls but not among boys. A similar pattern was found for internalizing disorders, whereas the administrative prevalences of externalizing disorders decreased. Regarding the severity of anorexia nervosa among inpatients, we found no pandemic-related changes in body mass index standard deviation score at admission, body weight loss before admission, psychiatric comorbidities and psychopharmacological medication. Given the administrative prevalence increase in the outpatient sector, the lack of impact of the pandemic on the inpatient sector may also be partly due to a shift in healthcare utilization towards outpatient services during the pandemic. Thus, the higher number of children and adolescents requiring specialized and timely outpatient care may be a major concern under pandemic conditions.

Plasmid replication based on the T7 origin of replication requires a T7 RNAP variant and inactivation of ribonuclease H.

T7 RNA polymerase (RNAP) is a valuable tool in biotechnology, basic research and synthetic biology due to its robust, efficient and selective transcription of genes. Here, we expand the scope of T7 RNAP to include plasmid replication. We present a novel type of plasmid, termed T7 ori plasmids that replicate, in an engineered Escherichia coli, with a T7 phage origin as the sole origin of replication. We find that while the T7 replication proteins; T7 DNA polymerase, T7 single-stranded binding proteins and T7 helicase-primase are dispensable for replication, T7 RNAP is required, although dependent on a T7 RNAP variant with reduced activity. We also find that T7 RNAP-dependent replication of T7 ori plasmids requires the inactivation of cellular ribonuclease H. We show that the system is portable among different plasmid architectures and ribonuclease H-inactivated E. coli strains. Finally, we find that the copy number of T7 ori plasmids can be tuned based on the induction level of RNAP. Altogether, this study assists in the choice of an optimal genetic tool by providing a novel plasmid that requires T7 RNAP for replication.

The impact of COVID-19 related lockdown measures on self-reported psychopathology and health-related quality of life in German adolescents.

The impact of school-closings on adolescents' mental health and well-being in the management of the ongoing COVID-19 pandemic is subject to ongoing public debate. Reliable data to inform a balanced discussion are limited. Drawing on a large ongoing multi-site project in Germany, we assessed differences in self-reported psychopathology in a matched convenience-sample of adolescents assessed pre- (November 26, 2018 to March 13, 2020; n = 324) and post the first lockdown (March 18, 2020 to August 29, 2020; n = 324) early 2020 in Germany. We found no evidence for an increase in emotional and behavioral problems, depression, thoughts of suicide or suicide attempts, eating disorder symptoms, or a decrease in general health-related quality of life. Reported suicide plans significantly decreased from 6.14 to 2.16%. Similarly, conduct problems decreased in the post-lockdown period. Family risk-factors did not moderate these findings. The influence of socioeconomic status on emotional and behavioral problems as well as depression decreased during the lockdown. Based on the present findings, the first school-closing in Germany had no immediate and severe impact on adolescents' well-being. However, caution is warranted as our data covers a fairly small, affluent sample over a limited time-span and long-term consequences cannot be ruled out.

Structure of Leishmania donovani 6-Phosphogluconate Dehydrogenase and Inhibition by Phosphine Gold(I) Complexes: A Potential Approach to Leishmaniasis Treatment.

As unicellular parasites are highly dependent on NADPH as a source for reducing equivalents, the main NADPH-producing enzymes glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) of the pentose phosphate pathway are considered promising antitrypanosomatid drug targets. Here we present the biochemical characterization and crystal structure of Leishmania donovani 6PGD (Ld6PGD) in complex with NADP(H). Most interestingly, a previously unknown conformation of NADPH is visible in this structure. In addition, we identified auranofin and other gold(I)-containing compounds as efficient Ld6PGD inhibitors, although it has so far been assumed that trypanothione reductase is the sole target of auranofin in Kinetoplastida. Interestingly, 6PGD from Plasmodium falciparum is also inhibited at lower micromolar concentrations, whereas human 6PGD is not. Mode-of-inhibition studies indicate that auranofin competes with 6PG for its binding site followed by a rapid irreversible inhibition. By analogy with other enzymes, this suggests that the gold moiety is responsible for the observed inhibition. Taken together, we identified gold(I)-containing compounds as an interesting class of inhibitors against 6PGDs from Leishmania and possibly from other protozoan parasites. Together with the three-dimensional crystal structure, this provides a valid basis for further drug discovery approaches.

Structural Analysis of Plasmodium falciparum Hexokinase Provides Novel Information about Catalysis Due to a Plasmodium-Specific Insertion.

The protozoan parasite Plasmodium falciparum is the causative pathogen of the most severe form of malaria, for which novel strategies for treatment are urgently required. The primary energy supply for intraerythrocytic stages of Plasmodium is the production of ATP via glycolysis. Due to the parasite's strong dependence on this pathway and the significant structural differences of its glycolytic enzymes compared to its human counterpart, glycolysis is considered a potential drug target. In this study, we provide the first three-dimensional protein structure of P. falciparum hexokinase (PfHK) containing novel information about the mechanisms of PfHK. We identified for the first time a Plasmodium-specific insertion that lines the active site. Moreover, we propose that this insertion plays a role in ATP binding. Residues of the insertion further seem to affect the tetrameric interface and therefore suggest a special way of communication among the different monomers. In addition, we confirmed that PfHK is targeted and affected by oxidative posttranslational modifications (oxPTMs). Both S-glutathionylation and S-nitrosation revealed an inhibitory effect on the enzymatic activity of PfHK.

An Optimized Dihydrodibenzothiazepine Lead Compound (SBI-0797750) as a Potent and Selective Inhibitor of Plasmodium falciparum and P. vivax Glucose 6-Phosphate Dehydrogenase 6-Phosphogluconolactonase.

In Plasmodium, the first two and rate-limiting enzymes of the pentose phosphate pathway, glucose 6-phosphate dehydrogenase (G6PD) and the 6-phosphogluconolactonase, are bifunctionally fused to a unique enzyme named GluPho, differing structurally and mechanistically from the respective human orthologs. Consistent with the enzyme's essentiality for malaria parasite proliferation and propagation, human G6PD deficiency has immense impact on protection against severe malaria, making PfGluPho an attractive antimalarial drug target. Herein we report on the optimized lead compound N-(((2R,4S)-1-cyclobutyl-4-hydroxypyrrolidin-2-yl)methyl)-6-fluoro-4-methyl-11-oxo-10,11-dihydrodibenzo[b,f][1,4]thiazepine-8-carboxamide (SBI-0797750), a potent and fully selective PfGluPho inhibitor with robust nanomolar activity against recombinant PfGluPho, PvG6PD, and P. falciparum blood-stage parasites. Mode-of-action studies have confirmed that SBI-0797750 disturbs the cytosolic glutathione-dependent redox potential, as well as the cytosolic and mitochondrial H2O2 homeostasis of P. falciparum blood stages, at low nanomolar concentrations. Moreover, SBI-0797750 does not harm red blood cell (RBC) integrity and phagocytosis and thus does not promote anemia. SBI-0797750 is therefore a very promising antimalarial lead compound.

Insights into the intracellular localization, protein associations and artemisinin resistance properties of Plasmodium falciparum K13.

The emergence of artemisinin (ART) resistance in Plasmodium falciparum intra-erythrocytic parasites has led to increasing treatment failure rates with first-line ART-based combination therapies in Southeast Asia. Decreased parasite susceptibility is caused by K13 mutations, which are associated clinically with delayed parasite clearance in patients and in vitro with an enhanced ability of ring-stage parasites to survive brief exposure to the active ART metabolite dihydroartemisinin. Herein, we describe a panel of K13-specific monoclonal antibodies and gene-edited parasite lines co-expressing epitope-tagged versions of K13 in trans. By applying an analytical quantitative imaging pipeline, we localize K13 to the parasite endoplasmic reticulum, Rab-positive vesicles, and sites adjacent to cytostomes. These latter structures form at the parasite plasma membrane and traffic hemoglobin to the digestive vacuole wherein artemisinin-activating heme moieties are released. We also provide evidence of K13 partially localizing near the parasite mitochondria upon treatment with dihydroartemisinin. Immunoprecipitation data generated with K13-specific monoclonal antibodies identify multiple putative K13-associated proteins, including endoplasmic reticulum-resident molecules, mitochondrial proteins, and Rab GTPases, in both K13 mutant and wild-type isogenic lines. We also find that mutant K13-mediated resistance is reversed upon co-expression of wild-type or mutant K13. These data help define the biological properties of K13 and its role in mediating P. falciparum resistance to ART treatment.

Increased hair cortisol in mothers of children with ADHD symptoms and psychosocial adversity background.

Parents of children with attention deficit hyperactivity disorder (ADHD) have shown high perceived parenting stress. Hence, physiological adjustment processes, involving the hypothalamic-pituitary-adrenal axis, seem possible. We hypothesized that (1) ADHD symptoms of the child predict an increase of maternal hair cortisol concentration (HCC), and (2) presence of psychosocial adversity amplifies the prediction. We analyzed a preschool-aged sample using a longitudinal design (T1, at the children's age of 4 years; T2, 12 months later). 128 mothers and their children participated in the study. To determine HCC of the previous 3 months, the first scalp-near 3 cm hair segment was used. ADHD symptoms of the child were measured using teacher- and parent-report questionnaires and a clinical interview with the mother. The T1 teacher-reported ADHD symptoms score of the child was significantly positively associated with the mother`s T1 and T2 HCC score. In families with high psychosocial adversity, the prediction of an increase in maternal HCC by the teacher-reported ADHD symptoms of child was significantly stronger than in low-adversity families. In presence of psychosocial family adversity, ADHD symptoms of the child predicted an increase in the mother's HCC. As a continuously high cortisol level implicates health risks and might in turn affect parenting resources, the identifying of caregivers at risk through biological markers of stress could be helpful for planning targeted interventions. As our study is the first on this issue, cross-validation is needed.

Intake of micronutrients and fatty acids of vegetarian, vegan, and omnivorous children (1-3 years) in Germany (VeChi Diet Study).

PURPOSE: There is an ongoing debate whether vegetarian (VG) and especially vegan (VN) diets are nutritionally adequate in early childhood. Hence, the Vegetarian and Vegan Children Study (VeChi Diet Study) aimed to assess the food and nutrient intake of VG and VN infants. METHODS: The study examined the diets of 1-3-year-old VG, VN, and omnivorous (OM) children (n = 430). Dietary intake was assessed via a 3-day weighed dietary record and compared between groups using ANCOVA. Lifestyle data were collected using a questionnaire. Here, the results of micronutrient and fatty acid intakes are presented. RESULTS: Most nutrient intakes (with and without supplements) differed significantly between VN children and the two other groups, with a more favourable overall micronutrient intake in VN, followed by VG children, [e.g., the highest intake of vitamin E (8.3 mg/d vs. VG 7.4 mg/d and OM 5.1 mg/d), vitamin B1 (569 µg/d vs. VG 513 µg/d and OM 481 µg/d), folate (143 µg/d vs. VG 116 µg/d and OM 108 µg/d), magnesium (241 mg/d vs. VG 188 mg/d and OM 164 mg/d), and iron (8.9 mg/d vs. VG 7.3 mg/d and OM 6.0 mg/d)] as well as fat quality [highest intake of polyunsaturated fatty acids (8.7 E% vs. VG 6.9 E% and OM 4.5 E%) and lowest intake of saturated fatty acids (9.1 E% vs. VG 11.9 E% and OM 14.0 E%)]. In contrast, OM children had the highest intake of vitamin B2 (639 µg/d vs. VG 461 µg/d and VN 429 µg/d), calcium (445 mg/d vs. VG 399 mg/d and VN 320 mg/d), iodine (47 µg/d vs. VG 33 µg/d and VN 31 µg/d), and DHA (35.4 mg/d vs. VG 16.6 mg/d and VN 18.4 mg/d). Without supplementation, OM children had the highest average vitamin B12 intake (1.5 µg/d vs. VG 0.6 µg/d and VN 0.2 µg/d), whereas VN children had the highest average vitamin B12 intake with supplementation (73.8 µg/d vs. VG 1.3 µg/d and OM 1.7 µg/d). Without supplementation, none of the groups' median intakes met the harmonised Average Requirement (h-AR) for vitamin D and iodine. Moreover, VG and VN children did not achieve h-ARs for vitamin B2, vitamin B12, and iron-if a low absorption of iron is anticipated; VN children also did not do so for calcium. CONCLUSION: In early childhood, VN and VG diets can provide most micronutrients in desirable amounts and a preferable fat quality compared to an OM diet. Special focus should be paid to (potentially) critical nutrients, particularly vitamin D, iodine, and DHA for all children regardless of diet, as well as vitamin B2, vitamin B12, calcium, and iron for VG and VN children. TRAIL REGISTRATION: This study was registered with the German Clinical Trials Register (DRKS00010982) on (September 2, 2016).

Chemistry of polyhalogenated nitrobutadienes, 17: Efficient synthesis of persubstituted chloroquinolinyl-1H-pyrazoles and evaluation of their antimalarial, anti-SARS-CoV-2, antibacterial, and cytotoxic activities.

A series of 26 novel 1-(7-chloroquinolin-4-yl)-4-nitro-1H-pyrazoles bearing a dichloromethyl and an amino or thio moiety at C3 and C5 has been prepared in yields up to 72% from the reaction of 1,1-bisazolyl-, 1-azolyl-1-amino-, and 1-thioperchloro-2-nitrobuta-1,3-dienes with 7-chloro-4-hydrazinylquinoline. A new way for the formation of a pyrazole cycle from 3-methyl-2-(2,3,3-trichloro-1-nitroallylidene)oxazolidine (6) is also described. In addition, the antimalarial activity of the synthesized compounds has been evaluated in vitro against the protozoan malaria parasite Plasmodium falciparum. Notably, the 7-chloro-4-(5-(dichloromethyl)-4-nitro-3-(1H-1,2,4-triazol-1-yl)-1H-pyrazol-1-yl)quinoline (3b) and 7-chloro-4-(3-((4-chlorophenyl)thio)-5-(dichloromethyl)-4-nitro-1H-pyrazol-1-yl)quinoline (9e) inhibited the growth of the chloroquine-sensitive Plasmodium falciparum strain 3D7 with EC50 values of 0.2 ± 0.1 µM (85 ng/mL, 200 nM) and 0.2 ± 0.04 µM (100 ng/mL, 200 nM), respectively. Two compounds (3b and 10d) have also been tested for anti-SARS-CoV-2, antibacterial, and cytotoxic activity.

Selective, Modular Probes for Thioredoxins Enabled by Rational Tuning of a Unique Disulfide Structure Motif.

Specialized cellular networks of oxidoreductases coordinate the dithiol/disulfide-exchange reactions that control metabolism, protein regulation, and redox homeostasis. For probes to be selective for redox enzymes and effector proteins (nM to µM concentrations), they must also be able to resist non-specific triggering by the ca. 50 mM background of non-catalytic cellular monothiols. However, no such selective reduction-sensing systems have yet been established. Here, we used rational structural design to independently vary thermodynamic and kinetic aspects of disulfide stability, creating a series of unusual disulfide reduction trigger units designed for stability to monothiols. We integrated the motifs into modular series of fluorogenic probes that release and activate an arbitrary chemical cargo upon reduction, and compared their performance to that of the literature-known disulfides. The probes were comprehensively screened for biological stability and selectivity against a range of redox effector proteins and enzymes. This design process delivered the first disulfide probes with excellent stability to monothiols yet high selectivity for the key redox-active protein effector, thioredoxin. We anticipate that further applications of these novel disulfide triggers will deliver unique probes targeting cellular thioredoxins. We also anticipate that further tuning following this design paradigm will enable redox probes for other important dithiol-manifold redox proteins, that will be useful in revealing the hitherto hidden dynamics of endogenous cellular redox systems.

Targeting spectrin redox switches to regulate the mechanoproperties of red blood cells.

The mechanical properties of red blood cells (RBCs) are fundamental for their physiological role as gas transporters. RBC flexibility and elasticity allow them to survive the hemodynamic changes in the different regions of the vascular tree, to dynamically contribute to the flow thereby decreasing vascular resistance, and to deform during the passage through narrower vessels. RBC mechanoproperties are conferred mainly by the structural characteristics of their cytoskeleton, which consists predominantly of a spectrin scaffold connected to the membrane via nodes of actin, ankyrin and adducin. Changes in redox state and treatment with thiol-targeting molecules decrease the deformability of RBCs and affect the structure and stability of the spectrin cytoskeleton, indicating that the spectrin cytoskeleton may contain redox switches. In this perspective review, we revise current knowledge about the structural and functional characterization of spectrin cysteine redox switches and discuss the current lines of research aiming to understand the role of redox regulation on RBC mechanical properties. These studies may provide novel functional targets to modulate RBC function, blood viscosity and flow, and tissue perfusion in disease conditions.

The impact of preschool child and maternal attention-deficit/hyperactivity disorder (ADHD) symptoms on mothers' perceived chronic stress and hair cortisol.

Providing care for a child with attention-deficit/hyperactivity disorder (ADHD) is associated with parenting stress. Moreover, adults with elevated ADHD symptoms report increased perceived stress. Despite this, it has rarely been examined whether and how child and maternal ADHD symptoms may affect maternal perceived stress and the stress-sensitive hypothalamic-pituitary-adrenal axis. This study therefore investigated the possible impact of child and maternal ADHD symptoms on mothers' perceived chronic stress and hair cortisol concentration (HCC), while simultaneously considering the effects of child oppositional defiant/conduct disorder (ODD/CD) and maternal depressive symptomatology. In total, 124 mothers (35.96 ± 5.21 years) of preschool children were included. Maternal perceived stress, ADHD and depressive symptoms were assessed using self-report measures. Child ADHD symptoms were assessed using an interview and questionnaires completed by mothers and teachers. Additionally, mothers provided information about their children's ODD/CD symptoms. Hair samples were taken from mothers to assess HCC. Child and maternal ADHD, child ODD/CD, and maternal depressive symptoms accounted for 50% of the variance in perceived chronic stress (F(4, 119) = 30.24; p < 0.01), with only maternal ADHD (ß = 0.52, p < 0.01) and depressive symptoms (ß = 0.49, p < 0.01) being uniquely significant. Maternal ADHD symptoms did not moderate the relationship between child ADHD symptoms and maternal perceived chronic stress (b = - 0.01; SE b = 0.17; t(5, 118) = - 0.05; p = 0.96). Mother's age became the only significant predictor of maternal HCC (ß = 0.29; p < 0.01). Based on these findings, practitioners are advised to be aware of and take into account possible maternal ADHD and depressive symptomatology and perceived chronic stress when treating children diagnosed with ADHD.

Editorial Perspective: A plea for the sustained implementation of digital interventions for young people with mental health problems in the light of the COVID-19 pandemic.

The coronavirus disease 2019 pandemic and the consequent global lockdown posed a particular challenge for youths with mental health problems. Crucial interference with their everyday lives likely increased psychological distress while accessibility of conventional mental health care was limited. Ongoing online trials offer a unique opportunity to analyse mental health status and help-seeking behaviour of adolescents during the pandemic. The ProHEAD-online trial aims at improving help-seeking behaviour of children and adolescents with significant psychological impairment. From January to May 2020, 1,042 students had access to the ProHEAD-online platform providing information on mental illness, monitoring, peer support and professional counselling. In the week from 11 March, when schools were closed in Germany, a drastic (more than 2 standard deviations) but time-limited increase in utilization of the ProHEAD-online services became apparent. This may indicate a worsened mental health status and an increased help seeking via digital services during the lockdown. Although this finding is purely observational, it speaks to the importance of evidence-based online service in the field of mental health within the current crisis and beyond.

Antimicrobial susceptibility patterns of respiratory Gram-negative bacterial isolates from COVID-19 patients in Switzerland.

BACKGROUND: Bacterial superinfections associated with COVID-19 are common in ventilated ICU patients and impact morbidity and lethality. However, the contribution of antimicrobial resistance to the manifestation of bacterial infections in these patients has yet to be elucidated. METHODS: We collected 70 Gram-negative bacterial strains, isolated from the lower respiratory tract of ventilated COVID-19 patients in Zurich, Switzerland between March and May 2020. Species identification was performed using MALDI-TOF; antibiotic susceptibility profiles were determined by EUCAST disk diffusion and CLSI broth microdilution assays. Selected Pseudomonas aeruginosa isolates were analyzed by whole-genome sequencing. RESULTS: Pseudomonas aeruginosa (46%) and Enterobacterales (36%) comprised the two largest etiologic groups. Drug resistance in P. aeruginosa isolates was high for piperacillin/tazobactam (65.6%), cefepime (56.3%), ceftazidime (46.9%) and meropenem (50.0%). Enterobacterales isolates showed slightly lower levels of resistance to piperacillin/tazobactam (32%), ceftriaxone (32%), and ceftazidime (36%). All P. aeruginosa isolates and 96% of Enterobacterales isolates were susceptible to aminoglycosides, with apramycin found to provide best-in-class coverage. Genotypic analysis of consecutive P. aeruginosa isolates in one patient revealed a frameshift mutation in the transcriptional regulator nalC that coincided with a phenotypic shift in susceptibility to ß-lactams and quinolones. CONCLUSIONS: Considerable levels of antimicrobial resistance may have contributed to the manifestation of bacterial superinfections in ventilated COVID-19 patients, and may in some cases mandate consecutive adaptation of antibiotic therapy. High susceptibility to amikacin and apramycin suggests that aminoglycosides may remain an effective second-line treatment of ventilator-associated bacterial pneumonia, provided efficacious drug exposure in lungs can be achieved.