SARS-Cov-2 Seroprevalence in a French Kidney Transplant Center Located Within a "High-risk" Zone.

BACKGROUND: Data on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in kidney transplant recipients (KTRs) remain rare. We sought to shed further light on this issue by conducting a single-center study in a kidney transplant center located in one of the France's highest risk zone (Grand Est) for coronavirus disease 2019 (Covid-19) during the initial disease outbreak. METHODS: To this aim, we used a survey approach coupled with systematic investigation of SARS-CoV-2 serology in a cohort of 1390 KTRs. RESULTS: SARS-CoV-2 serologies were available for 780 survey respondents, among whom 48 had anti-SARS-CoV-2 antibodies (total seroprevalence: 6.2%). Thirty-five of the 48 seropositive KTRs had previously received a diagnosis of Covid-19, whereas the remaining 13 patients were not known to be infected (8 asymptomatic cases). Specifically, 18.7% of seropositive KTRs and 1.1% of the entire cohort were asymptomatic. Household exposure was found to markedly increase the risk of SARS-CoV-2 transmission. CONCLUSIONS: Our findings demonstrate that the overall SARS-CoV-2 seroprevalence in KTRs living in one of the France's highest risk zone for Covid-19 during the first French lockdown was as low as 6.3%. Rapid and strict implementation of protective measures could have significantly mitigated virus spread even in an area of high virus circulation.

Implications of the Sap47 null mutation for synapsin phosphorylation, longevity, climbing proficiency and behavioural plasticity in adult Drosophila.

The Sap47 gene of Drosophila melanogaster encodes a highly abundant 47 kDa synaptic vesicle-associated protein. Sap47 null mutants show defects in synaptic plasticity and larval olfactory associative learning but the molecular function of Sap47 at the synapse is unknown. We demonstrate that Sap47 modulates the phosphorylation of another highly abundant conserved presynaptic protein, synapsin. Site-specific phosphorylation of Drosophila synapsin has repeatedly been shown to be important for behavioural plasticity but it was not known where these phospho-synapsin isoforms are localized in the brain. Here, we report the distribution of serine-6-phosphorylated synapsin in the adult brain and show that it is highly enriched in rings of synapses in the ellipsoid body and in large synapses near the lateral triangle. The effects of knockout of Sap47 or synapsin on olfactory associative learning/memory support the hypothesis that both proteins operate in the same molecular pathway. We therefore asked if this might also be true for other aspects of their function. We show that knockout of Sap47 but not synapsin reduces lifespan, whereas knockout of Sap47 and synapsin, either individually or together, affects climbing proficiency, as well as plasticity in circadian rhythms and sleep. Furthermore, electrophysiological assessment of synaptic properties at the larval neuromuscular junction (NMJ) reveals increased spontaneous synaptic vesicle fusion and reduced paired pulse facilitation in Sap47 and synapsin single and double mutants. Our results imply that Sap47 and synapsin cooperate non-uniformly in the control of synaptic properties in different behaviourally relevant neuronal networks of the fruitfly.

An essential role of the mouse synapse-associated protein Syap1 in circuits for spontaneous motor activity and rotarod balance.

Synapse-associated protein 1 (Syap1) is the mammalian homologue of synapse-associated protein of 47 kDa (Sap47) in Drosophila Genetic deletion of Sap47 leads to deficiencies in short-term plasticity and associative memory processing in flies. In mice, Syap1 is prominently expressed in the nervous system, but its function is still unclear. We have generated Syap1 knockout mice and tested motor behaviour and memory. These mice are viable and fertile but display distinct deficiencies in motor behaviour. Locomotor activity specifically appears to be reduced in early phases when voluntary movement is initiated. On the rotarod, a more demanding motor test involving control by sensory feedback, Syap1-deficient mice dramatically fail to adapt to accelerated speed or to a change in rotation direction. Syap1 is highly expressed in cerebellar Purkinje cells and cerebellar nuclei. Thus, this distinct motor phenotype could be due to a so-far unknown function of Syap1 in cerebellar sensorimotor control. The observed motor defects are highly specific since other tests in the modified SHIRPA exam, as well as cognitive tasks like novel object recognition, Pavlovian fear conditioning, anxiety-like behaviour in open field dark-light transition and elevated plus maze do not appear to be affected in Syap1 knockout mice.

Initial characterization of a Syap1 knock-out mouse and distribution of Syap1 in mouse brain and cultured motoneurons.

Synapse-associated protein 1 (Syap1/BSTA) is the mammalian homologue of Sap47 (synapse-associated protein of 47 kDa) in Drosophila. Sap47 null mutant larvae show reduced short-term synaptic plasticity and a defect in associative behavioral plasticity. In cultured adipocytes, Syap1 functions as part of a complex that phosphorylates protein kinase Bα/Akt1 (Akt1) at Ser(473) and promotes differentiation. The role of Syap1 in the vertebrate nervous system is unknown. Here, we generated a Syap1 knock-out mouse and show that lack of Syap1 is compatible with viability and fertility. Adult knock-out mice show no overt defects in brain morphology. In wild-type brain, Syap1 is found widely distributed in synaptic neuropil, notably in regions rich in glutamatergic synapses, but also in perinuclear structures associated with the Golgi apparatus of specific groups of neuronal cell bodies. In cultured motoneurons, Syap1 is located in axons and growth cones and is enriched in a perinuclear region partially overlapping with Golgi markers. We studied in detail the influence of Syap1 knockdown and knockout on structure and development of these cells. Importantly, Syap1 knockout does not affect motoneuron survival or axon growth. Unexpectedly, neither knockdown nor knockout of Syap1 in cultured motoneurons is associated with reduced Ser(473) or Thr(308) phosphorylation of Akt. Our findings demonstrate a widespread expression of Syap1 in the mouse central nervous system with regionally specific distribution patterns as illustrated in particular for olfactory bulb, hippocampus, and cerebellum.

[Cognitive and emotional empathy in children with ADHD and conduct disorder]. / Kognitive und emotionale Empathie bei Kindern und Jugendlichen mit ADHS und Störung des Sozialverhaltens.

OBJECTIVES: This study assesses the cognitive and emotional empathic competence in groups of children and adolescents with psychiatric disorders compared to a nonclinical control group. Subjective and objective diagnostic measures were employed. METHODS: A total of 96 boys were tested: 20 with attention-deficit/hyperactivity disorder (ADHD) predominantly inattentive subtype (ADHD-I); 20 with ADHD combined subtype (ADHD-C); 20 with conduct disorder (CD); 36 healthy boys (control group; CG). Mean age was 12.0 years (SD = 2.36). As aspects of cognitive and emotional empathy emotional reactivity, we tested emotion recognition and perspective taking with subjective questionnaires and objective tasks, using as subjective questionnaires the Interpersonal Reactivity Index (IRI; Davis, 1983) and the Index of Empathy for Children and Adolescents (IECA; Bryant, 1982). As objective tasks, we adopted the Empathy Response Task (ERT; Ricard & Kamberk-Kilicci, 1995) and a task measuring emotion recognition according to Buitelaar et al. (1999). RESULTS: The CG outperformed participants with ADHD-C and CD in objective tasks assessing perspective taking, particularly when complex tasks were applied as stimuli. Children with ADHD-I showed significantly more emotional empathy than boys with ADHD-C when presented with simple tasks. No group differences were found for emotion recognition and subjective questionnaires. DISCUSSION: Deficits in perspective taking and emotional empathy were found for children with ADHD-C and CD, largely in accordance with the literature. Similar to the processing of cognitive information, the processing of emotional information seems to differ in ADHD subtypes. Objective tasks and tasks with a high ecological validity seem suitable for the measurement of empathy.