Haploinsufficiency of the 22q11.2 microdeletion gene Mrpl40 disrupts short-term synaptic plasticity and working memory through dysregulation of mitochondrial calcium.

Hemizygous deletion of a 1.5- to 3-megabase region on chromosome 22 causes 22q11.2 deletion syndrome (22q11DS), which constitutes one of the strongest genetic risks for schizophrenia. Mouse models of 22q11DS have abnormal short-term synaptic plasticity that contributes to working-memory deficiencies similar to those in schizophrenia. We screened mutant mice carrying hemizygous deletions of 22q11DS genes and identified haploinsufficiency of Mrpl40 (mitochondrial large ribosomal subunit protein 40) as a contributor to abnormal short-term potentiation (STP), a major form of short-term synaptic plasticity. Two-photon imaging of the genetically encoded fluorescent calcium indicator GCaMP6, expressed in presynaptic cytosol or mitochondria, showed that Mrpl40 haploinsufficiency deregulates STP via impaired calcium extrusion from the mitochondrial matrix through the mitochondrial permeability transition pore. This led to abnormally high cytosolic calcium transients in presynaptic terminals and deficient working memory but did not affect long-term spatial memory. Thus, we propose that mitochondrial calcium deregulation is a novel pathogenic mechanism of cognitive deficiencies in schizophrenia.

[ZIKA FEVER: CLINICAL, EPIDEMIOLOGICAL, LABORATORY, AND DIAGNOSTIC ASPECTS].

The authors overview data on the prevalence of Zika fever with reference to biological properties of the causative agent, epidemiological process, pathogenesis, and clinical symptoms of the disease. Special attention is given to the identification of the virus in pregnant women, microcephaly in the babies born by Zika-infected women, algorithm of laboratory diagnostics, and measures needed to prevent and control mosquitoes that spread viruses.

[Evacuation of contagious patients in the modern system of medical support].

Evacuation of contagious patients in the modern system. of medical support. The main problematic issues of organizing and conducting the evacuation of contagious patients are defined. A peculiarity of evacuation and healthcare delivery to contagious patients is the need for permanent complex of sanitary and anti-epidemic (preventive) measures aimed at preventing the spread of infectious diseases. Set out fundamental approaches to triage of infectious patients at different stages of medical evacuation, defined sorting group. The attention is focused on the clinical-and-syndrome principle infectious pathology diagnostics. The experience of the medical evacuation of infectious diseases in Afghanistan is analysed. The necessity of protecting the accompanying medical staff is showed. The possibilities, the benefits and how to use for the isolation of infectious patients and the evacuation of mobile autonomous units - the transport of insulating boxes are studied.

[Zika virus infection: clinical and diagnostic aspects and organization of preventive measures].

The article presents modem data about Zika virus outbreak, the biological characteristics of the pathogen, vectors, the nature of the epidemic process, pathogenesis and diagnosis of infection. This infection has a high potential for epidemic spread because vectors are widely represented in the fauna of many climatic and geographic zones. It presents information on the main clinical manifestations of the disease. Particular attention is paid to the problem of congenital maiformations of the nervous system (microcephaly and others) detected in infants born to women infected with Zika virus. The basis of therapy in this disease constitute a pathogenic agent. The'package of, measures for the prevention of disease caused by Zika virus, including early identification and treatment of patients, as well as measures for the destruction of the virus vectors.

[EBOLA HEMORRHAGIC FEVER: DIAGNOSTICS, ETIOTROPIC AND PATHOGENETIC THERAPY, PREVENTION].

The data on diagnostics, etiotropic and pathogenetic therapy, prevention of Ebola hemorrhagic fever are presented including diagnostic algorithms for different clinical situations. Fundamentals of pathogenetic therapy are described. Various groups of medications used for antiviral therapy of conditions caused by Ebola virus are characterized. Experimental drugs at different stages of clinical studies are considered along with candidate vaccines being developed for the prevention of the disease.

[EBOLA HEMORRHAGIC FEVER; ETIOLOGY, EPIDEMIOLOGY, PATHOGENESIS, AND CLINICAL SYMPTOMS].

The data on the prevalence of disease caused by Ebola virus, biological features of its pathogen, character of the epidemiological process, pathogenesis and clinical symptoms are presented. The disease is characterized by suppression of protective immunological mechanisms and systemic inflammatory reaction accounting for the lesions of vascular endothelium, hemostatic and immune systems. It eventually leads to polyorgan insufficiency and severe shock. Lethality amounts to 50%.

[Treatment of Ebola virus disease].

Treatment of Ebola virus disease. The article presents data on the etiology, pathogenesis, clinical presentation, diagnosis and modern approaches to the treatment of Ebola haemorrhagic fever. This serious infectious disease with a high fatality rate is characterized by intoxication, severe haemorrhages, disseminated intravascular coagulation, and multiple organ failure with the development of severe shock. It is emphasized that the treatment of patients with Ebola should be conducted under strict anti-epidemic regime. Since there is currently no effective drugs against Ebola virus, the basis of modern treatment of this disease are pathogenic and symptomatic treatments. The main activities should be aimed at correcting violations homeostasis, blood volume deficiency, disorders of water and electrolyte balance, acid-base status osmolar and oncotic pressure shortfall of clotting factors and blood components. The treatment program should be drawn up taking into account the stage of the disease, the severity of the course and comorbidity.

[Meningococcal disease: early clinical diagnosis and emergency care].

Late diagnosis of meningococcal disease leads to high mortality. Early diagnosis of its generalized forms plays a crucial role in the pre-hospital phase and mainly based on the clinical picture of the disease. In most cases, pre-hospital typical mistake is late diagnosis of meningococcal disease: We propose an algorithm of early diagnosis of generalized forms of the disease in order to reduce the number of diagnostic errors. Proper and timely diagnosis will enable the physician pre-hospital fully implement measures to provide emergency and urgent care in generalized meningococcal infection, leading to. a more.favourable course and a significant improvement in the outcomes of the disease in the course of further hospital treatment.

[Ebola virus disease: clinical and diagnostic aspects and organization of treatment-and-prophylactic measures].

The article presents data about world spread of Ebola virus disease, biological characteristics of the pathogen, the laws of the epidemic process in this disease, its pathogenesis, clinical manifestations and diagnosis. Pointed out that the current anti-viral agents, effective for the Ebola virus, have not been developed. Timely performed pathogenetic therapy improves the prognosis of the disease. The basis of this therapy is infusion-detoxification activities and replenishment of losses, of electrolytes, as well as anti-inflammatory and anti-emetic drugs. The Armed Forces of the Russian Federation received the guidelines for preventive measure that can reduce Ebola virus disease transmission. Recommendations for emergency anti-epidemic commission consisted of representatives of the command, specialists and medical services and logistics, are given. Fundamentally important condition for the effective anti-epidemic measures is not only the constant readiness of medical personnel in the detection of disease EVD, but also the appropriate level of equipment of medical institutions of medical supplies and equipment.

General dynamics of the URT microbiome and microbial signs of recovery in COVID-19 patients.

COVID-19 is caused by an airborne virus, SARS-CoV-2. The upper respiratory tract (URT) is, therefore, the first system to endure the attack. Inhabited by an assemblage of microbial communities, a healthy URT wards off the invasion. However, once invaded, it becomes destabilised, which could be crucial to the establishment and progression of the infection. We examined 696 URT samples collected from 285 COVID-19 patients at three time-points throughout their hospital stay and 100 URT samples from 100 healthy controls. We used 16S ribosomal RNA sequencing to evaluate the abundance of various bacterial taxa, α-diversity, and ß-diversity of the URT microbiome. Ordinary least squares regression was used to establish associations between the variables, with age, sex, and antibiotics as covariates. The URT microbiome in the COVID-19 patients was distinctively different from that of healthy controls. In COVID-19 patients, the abundance of 16 genera was significantly reduced. A total of 47 genera were specific to patients, whereas only 2 were unique to controls. The URT samples collected at admission differed more from the control than from the samples collected at later stages of treatment. The following four genera originally depleted in the patients grew significantly by the end of treatment: Fusobacterium, Haemophilus, Neisseria, and Stenotrophomonas. Our findings strongly suggest that SARS-CoV-2 caused significant changes in the URT microbiome, including the emergence of numerous atypical taxa. These findings may indicate increased instability of the URT microbiome in COVID-19 patients. In the course of the treatment, the microbial composition of the URT of COVID-19 patients tended toward that of controls. These microbial changes may be interpreted as markers of recovery.

[Perspective applications of multi-species probiotics in the prevention of antibiotic-associated diarrhea].

The problem of antibiotic-associated conditions is one of the most actual problems of clinical practice. The antibiotic-associated diarrhea is a multidisciplinary problem. Investigations of the small intestine microecological status and assessment of microflora at the patients receiving antibiotics testifies to dysbiosis existence. In article results of open-label investigation of a multispecies probiotic RioFlora Balance using for antibiotic-associated diarrhea prophylaxis in patients used antibacterial therapy are presented.

[Delivery of healthcare to patients with infectious diseases during the pre-hospital stage].

In the field infectious military hospital work with double-triple overcharge. It leads to reduction of health care to patients, requires the additional hospital departments or evacuation of contagious patients to other hospitals. That is why the pre-hospital care is of prime importance. According to modem concept the number of interim stages is minimal--1 stage--on site of definition of contagious patients (isolator of medical station of military unit) and 2 stage--infectious military hospital. Main measures of health care to contagious patients during the pre-hospital stage are early active detection of patients or suspected of having infection, early clinical diagnosis, medical sorting, delivery of emergency care, treatment in isolators in case of delay of evacuation and evacuation in infectious military hospital.

[Infection agents and irritable bowel syndrome].

The discussion concerns onset and pathogenesis of functional intestinal diseases. Current data are presented on association of functional intestinal diseases with different infectious agents with illustration on the model of postinfectious irritable colon syndrome (ICS). ICS-like conditions in patients who had previously intestinal infections are considered.

[Intestinal dysbiosis in liver cirrhosis].

Intestinal dysbiosis is revealed in 28.5% of patients with liver cirrhosis, mainly in classes B and C by Child-Pugh by the results of hydrogen breath test. It is established that revealed intestinal dysbiosis in patients with liver cirrhosis of viral etiology aggravates the course of the disease.

Dynamics of axonal microtubules regulate the topology of new membrane insertion into the growing neurites.

Nerve growth depends on the delivery of cell body-synthesized material to the growing neuronal processes. The cellular mechanisms that determine the topology of new membrane addition to the axon are not known. Here we describe a technique to visualize the transport and sites of exocytosis of cell body- derived vesicles in growing axons. We found that in Xenopus embryo neurons in culture, cell body-derived vesicles were rapidly transported all the way down to the growth cone region, where they fused with the plasma membrane. Suppression of microtubule (MT) dynamic instability did not interfere with the delivery of new membrane material to the growth cone region; however, the insertion of vesicles into the plasma membrane was dramatically inhibited. Local disassembly of MTs by focal application of nocodazole to the middle axonal segment resulted in the addition of new membrane at the site of drug application. Our results suggest that the local destabilization of axonal MTs is necessary and sufficient for the delivery of membrane material to specific neuronal sites.

Neurotransmitter secretion along growing nerve processes: comparison with synaptic vesicle exocytosis.

In mature neurons, synaptic vesicles continuously recycle within the presynaptic nerve terminal. In developing axons which are free of contact with a postsynaptic target, constitutive membrane recycling is not localized to the nerve terminal; instead, plasma membrane components undergo cycles of exoendocytosis throughout the whole axonal surface (Matteoli et al., 1992; Kraszewski et al., 1995). Moreover, in growing Xenopus spinal cord neurons in culture, acetylcholine (ACh) is spontaneously secreted in the quantal fashion along the axonal shaft (Evers et al., 1989; Antonov et al., 1998). Here we demonstrate that in Xenopus neurons ACh secretion is mediated by vesicles which recycle locally within the axon. Similar to neurotransmitter release at the presynaptic nerve terminal, ACh secretion along the axon could be elicited by the action potential or by hypertonic solutions. We found that the parameters of neurotransmitter secretion at the nerve terminal and at the middle axon were strikingly similar. These results lead us to conclude that, as in the case of the presynaptic nerve terminal, synaptic vesicles involved in neurotransmitter release along the axon contain a complement of proteins for vesicle docking and Ca2+-dependent fusion. Taken together, our results support the idea that, in developing axons, the rudimentary machinery for quantal neurotransmitter secretion is distributed throughout the whole axonal surface. Maturation of this machinery in the process of synaptic development would improve the fidelity of synaptic transmission during high-frequency stimulation of the presynaptic cell.

Phosphatase and tensin homolog, deleted on chromosome 10 deficiency in brain causes defects in synaptic structure, transmission and plasticity, and myelination abnormalities.

The phosphatidylinositol 3-kinase (PI3K) signaling pathway modulates growth, proliferation and cell survival in diverse tissue types and plays specialized roles in the nervous system including influences on neuronal polarity, dendritic branching and synaptic plasticity. The tumor-suppressor phosphatase with tensin homology (PTEN) is the central negative regulator of the PI3K pathway. Germline PTEN mutations result in cancer predisposition, macrocephaly and benign hamartomas in many tissues, including Lhermitte-Duclos disease, a cerebellar growth disorder. Neurological abnormalities including autism, seizures and ataxia have been observed in association with inherited PTEN mutation with variable penetrance. It remains unclear how loss of PTEN activity contributes to neurological dysfunction. To explore the effects of Pten deficiency on neuronal structure and function, we analyzed several ultra-structural features of Pten-deficient neurons in Pten conditional knockout mice. Using Golgi stain to visualize full neuronal morphology, we observed that increased size of nuclei and somata in Pten-deficient neurons was accompanied by enlarged caliber of neuronal projections and increased dendritic spine density. Electron microscopic evaluation revealed enlarged abnormal synaptic structures in the cerebral cortex and cerebellum. Severe myelination defects included thickening and unraveling of the myelin sheath surrounding hypertrophic axons in the corpus callosum. Defects in myelination of axons of normal caliber were observed in the cerebellum, suggesting intrinsic abnormalities in Pten-deficient oligodendrocytes. We did not observe these abnormalities in wild-type or conditional Pten heterozygous mice. Moreover, conditional deletion of Pten drastically weakened synaptic transmission and synaptic plasticity at excitatory synapses between CA3 and CA1 pyramidal neurons in the hippocampus. These data suggest that Pten is involved in mechanisms that control development of neuronal and synaptic structures and subsequently synaptic function.

Visualization of changes in presynaptic function during long-term synaptic plasticity.

Controversy exists regarding the site of modification of synaptic transmission during long-term plasticity in the mammalian hippocampus. Here we used a fluorescent marker of presynaptic activity, FM 1-43, to directly image changes in presynaptic function during both short-term and long-term forms of plasticity at presynaptic boutons of CA3-CA1 excitatory synapses in acute hippocampal slices. We demonstrated enhanced presynaptic function during long-term potentiation (LTP) induced either chemically (with tetraethylammonium), or by high-frequency (200-Hz) electrical stimulation. Both of these forms of LTP required activation of L-type voltage-gated calcium channels and NMDA receptors in the postsynaptic CA1 neuron. These results thus implied that a long-lasting increase in the efficacy of synaptic transmission is likely to depend, at least in part, on enhanced transmitter release from the presynaptic neuron.

Epidemiological, clinical and viral determinants of the increased prevalence of high-risk human papillomavirus (HPV) infections in elderly women.

BACKGROUND: Population-based studies have reported a second peak of human papillomavirus (HPV) prevalence among women > 55 years, but reasons for this U-shaped HPV prevalence curve are poorly understood. OBJECTIVES: To analyse determinants of high-risk HPV (HR-HPV) infections among postmenopausal women. STUDY DESIGN AND METHODS: A cohort of 3,187 women was stratified into three age categories: i) youngest age group < 25 years (n = 1.103); ii) women between 26-55 years (n = 2.004), and iii) women > 55 years (n = 80), analysed for epidemiological, clinical and virological determinants of their HR-HPV infections. Real-time PCR was used for HPV genotyping, analysis of viral loads for HPV16, 18/45, 31, 33/52/58, 35 and 39, and load of integrated HPV16. RESULTS: Age-standardised prevalence of HR-HPV infections showed a second peak among women > 55 years, with a perfect U-shaped curve (R2 = 0.966). The factors explaining this increased HR-HPV prevalence among older women include: i) cohort effect, ii) higher viral loads for HR-HPV types with cubic model curve (R2 = 0.714) for HPV 16, iii) distinct shift (p = 0.0001) from multiple-type infections to single HR-HPV types, iv) transition from episomal to integrated HPV16 (p = 0.009), v) higher load of integrated HPV16 (p = 0.009), and, vi) higher proportion of incident infections, higher rate of viral persistence, and lower rate of HR-HPV clearance. CONCLUSIONS: These data suggest that in women who fail to eradicate their HR-HPV infection until menopause, selection of integrated viral clone has taken place, driving the process towards progressing disease. Consequent to this, most of the HR-HPV infections in women > 55 years were associated with high-grade CIN or invasive carcinoma.