The initial level of heart rate variability determines the dynamics of the neuropathy of the autonomic nervous system and temperature sensitivity in rats with streptozotocin diabetes

BACKGROUND: The development of diabetes mellitus (DM) is accompanied by hyperglycemia, which leads to the development of neuropathy. We assume that the individual characteristics of the organization of the autonomic nervous system (ANS) in humans affect not only the ability to withstand stress, but can determine the course of diseases, including diabetes. AIMS: The study of the dynamics of heart rate variability and temperature sensitivity in rats against the background of hyperglycemia depending on the organization of the initial regulation of the heart under ANS. MATERIALS AND METHODS: 70 male rats were randomized by weight and level of total heart rate variability (HRV) on animals with initially low and high levels of total HRV. Diabetes was modeled by a single i.p. injection of streptozotocin (STZ). The control group received a single i.p. injection of citrate buffer (CB). Before the induction of diabetes, as well as on 21, 42 and 70 days after the injection of STZ, a comprehensive examination of rats’ condition was carried out: 1) assessment of HRV; 2) analysis of temperature-pain sensitivity; 3) assessment of glucose and ketone bodies in the blood. Similarly, animals in the CB group were examined. RESULTS: The change in HRV and temperature-pain sensitivity in rats depends on the initial level of HRV. In rats with low variability, the reaction time in the pain test increased by 8–32% from the 28th day of the experiment, from 21 days the bradycardia increased and the decrease in individual HRV indices at rest, but not the response of these parameters to cold stress. CONCLUSION: The development of ANS’s lesion depends on the initial level of HRV. Low variability animals are more resistant to hyperglycemia: the normal ranges of CP reactions from the side of HR, the parameters of total HRV and the CVHS contribution to it are longer, but there is a loss of temperature sensitivity. Initially, highly variable rats with the development of diabetes do not lose temperature sensitivity, but demonstrate an imbalance in the regulatory circuits of heart rate and HRV

Dynamics of heart rate variability in rats with streptozotocin-induced diabetes

Background: Diabetes mellitus (DM) has a negative impact on all organs. This is due to insufficiency of blood supply and the disruption of the trophic function of the nervous system. One of the most serious complication of DM is diabetic foot caused be vascular and neurological reasons. Correction of vascular disorders is effectively treated by modern therapeutic approaches, but the damage of nervous system has been studied insufficiently. Aims: To investigate the dynamics of damage to the vegetative nervous system on the laboratory model of DM. Materials and methods: DM in rats was induced by injection of streptozotocin at a dose of 65 mg/kg in citrate buffer (DM group). The control group of rats received a citrate buffer equivalent (CB group). Rats with DM were given a maintenance therapy with insulin in a dose of 2 units/kg/day. On 42 days of experience, a round wound with a diameter of 2 cm on the back of the animals was observed. Before the DM simulation, then on the 42, 50, 58 and 66 days of its development, an electrocardiogram (ECG) was recorded in the rats at a frequency of 2 kHz digitising in a state of calm wakefulness and after cold exposure. For 5 minutes ECG fragments, heart rate and heart rate variability (HRV) in the temporal domain were calculated, characterising: 1) the total heart rate variability (tHRV) according to SDRR, SDHR, KVRR and KVHR; 2) the effect of the parasympathetic department of the autonomic nervous system (aANS) for RMSSD and pNN3; 3) the contribution of the sympathetic department of the ANS (sANS) by SDAvgRR, SDAvgHR. The spectral parameters were estimated in the frequency domain: the total power of the spectrum is TR (range: 0–2.5 Hz), the powers in the low and high frequency ranges are LF (range: 0.2–0.8 Hz) and HF (range: 0.8–2.5 Hz) LF/HF. Weekly, the tail withdrawal time was measured in a temperature pain test (55°C). Results: During the development of diabetes, the level of glucose in the blood increased 4–7 times compared with the normal level. The reaction time of the pain test in rats with DM increased by 20%–30% at the end of the experiment. At 42 days, the development of bradycardia (267 beats/min) was observed in rats with DM. The indicators of tHRV decreased by a factor of 2 due to a decrease in the contribution of sANS. The reaction to CP in the SD group differs from the norm by the severity of the individual components of the HRV structure, which indicates functional denervation of the heart and the development of diabetic neuropathy. Conclusions: As the diabetes progressed, signs of neuropathy were observed. The overall HRV parameters decreased, the ratio of the contributions of sANS and pANS to the regulation of heart rate changed, and the temperature sensitivity decreased

Electrical activity in rat retina in a streptozotocin-induced diabetes model

Objectives: Diabetic retinopathy remains the major cause of blindness among the working-age population of developed countries. Considering this, experimental models of diabetes involving laboratory animals are important for assessing clinically significant methods to determine early pathologic alterations of the retina. The early detection of diabetic retinopathy in combination with a search for new pathogenetic targets will enable focusing on new strategies to limit the development of critical changes in the retina and to prolong retinal functioning during the development of diabetes mellitus. Aim: This study aimed to define parameters of electroretinography test that identifies changes due to retinal impairment in diabetes. Methods: Experimental diabetes was induced in Wistar rats by intraperitoneally injecting streptozocin (65 mg/kg; group DM). The control group (CB) received intraperitoneal injections of the vehicle, i.e. citric buffer. On each consecutive day of the experiment, all rats received insulin detemir (2 u/kg). Ophthalmoscopy and electroretinography were conducted before initiating the experiment and after 50, 58 and 66 days of injectin sptreptozocin. Results: Amid 2u\kg insulin injection the glucose level in venous blood in DM group amounted to 30-40 mM. The ophthalmoscopy showed that the optic nerve disk paled by the 50th day, with its line erasing. During electroretinography, wave amplitude in oscillatory potential test tended to decrease. -wave latency of photopic system increased with -wave latency of photopic system and - and -waves latency of scotopic system not altering. In addition, the amplitude of rhythmic stimulation of 8 and 12 Hz decreased. Conclusion: The most apparent parameters of electroretinography for modelling streptozocin-induced diabetes are wave amplitude during the oscillatory potential test, photopic B-wave latency and the amplitude of rhythmic stimulation. These results suggest that in diabetes, ischaemic injury is an important cause of early dysfunction of inner retinal layers

Characteristics of Lipid Peroxidation Processes and Antioxidant Status in Teenagers-Boys of Different Ethnic Groups with Exogenous Constitutional Obesity and Non-Alcoholic Fatty Liver Disease

The aim of this research was to study changes in the LPO-AOD processes in Mongoloid and Caucasian teenagers with exogenous constitutional obesity (ECO), including those complicated by non-alcoholic fatty liver disease (NAFLD). Materials and Methods: A total of 18 Mongoloid teenage boys and 17 Caucasian teenage boys with NAFLD (Clinical group 1 and Clinical group 2, respectively) on the background of ECO of the first degree were examined. For comparison, data of 37 apparently healthy Mongoloid teenage boys (Control group 1) and 23 Caucasian teenage boys (Control group 2) was used. The plasma level of antioxidant parameters (total antioxidant activity [TTA], SOD activity, α-tocopherol and retinol) and primary/secondary products of LPO (conjugated dienes [CD], ketodienes and conjugated trienes [KD-CT], and thiobarbituric acid reactive substances [TBARS]) were determined using spectrophotometric and fluorometric methods. Results: Evaluation of the activity of LPO reactions in Clinical group 1 indicated an increase in the content of compounds with DB relative to Control group 1. A similar trend was found in the concentration of CD and KD-CT. In Clinical group 2, we found a statistically significant increase only in the values of KD-CT. In the parameters of the AOD system, multidirectional changes of patients parameters compared with the control group were observed in Clinical group 1: the increased values of TAA, SOD activity, and reduced levels of α-tocopherol, retinol, and GSSG. In Clinical group 2, lower values of α-tocopherol, GSSG, and SOD activity were observed relative to Control group 2. Differences between the two ethnic groups were present in the control groups—the reduced level of TAA, GSH and the increased level of GSSG in the group of Mongoloids; just as in clinical groups with NAFLD, a high level of SOD activity was observed in Mongoloids compared to Caucasians. Conclusion: The changes revealed in the redox state in Mongoloid and Caucasian teenagers with ECO and NAFLD indicate high activity of LPO processes and severe deficiency of antioxidant vitamins in patients of both ethnic groups. The obtained results allow us to recommend administration of antioxidant drugs in addition to courses of metabolic therapy in comprehensive treatment of patients with ECO and NAFLD

Keratinocytes differentiation and wound healing in rats with streptozotocin – induced diabetes and severe hyperglycemia

BACKGROUND: Diabetes mellitus leads to disruption of the skin repair processes, but the leading mechanisms of this pathology have not yet been identified. In this regard, in our work, we decided to check how hyperglycaemia affects the process of keratinocyte phenotype changes during wound healing. AIMS: To study the effect of hyperglycaemia on wound healing and differentiation of keratinocytes in a rat streptozotocin-induced diabetes model. MATERIALS AND METHODS: Diabetes mellitus was induced in rats by using streptozotocin, 65 mg / kg, intraperitoneally, once. The wound was applied in the supra-scapular region on the 42nd day, after which (after 8, 16, and 24 days) the repair process was evaluated using histological methods. Immunohistochemistry was used to evaluate the expression of cytokeratin-10 and cytokeratin-17. RESULTS: In rats with diabetes mellitus, wound healing slowed down in the later stages, compared with the control group. In general, wound healing was accompanied by an increase in the expression of cytokeratin-10 in its region compared with intact skin, and contractile keratinocytes activation was disrupted in diabetic rat wounds. CONCLUSIONS: Hyperglycaemia slightly slows wound healing in rats and impairs contractile keratinocytes activation

Assessment of physicians’ and senior medical students’ knowledge in treatment of patients with community acquired pneumonia: Current results of the KNOCAP project

Introduction. Community-acquired pneumonia (CAP) remains one of the most acute problems of bronchopulmonary pathology being the 4th in the mortality structure (after cardiovascular, cerebrovascular diseases and malignant neoplasms) and the 1st among all fatalities from infectious diseases. Thanks to the scientific progress achieved in the antibiotic therapy and vaccine prophylaxis, the death toll has decreased four times compared to its rate during the “pre-antibiotic era“. However, nowadays there is a steadily increasing trend in the pneumonia mortality rate in Russia. The only possible way to increase efficacy of CAP treatment is timely initiated rational antibiotic therapy, considering the possible etiologies, risk factors and the severity of the patient’s condition. Materials and methods. The article represents the results of anonymous prospective surveys within the framework of the KNOCAP multi-centered research project aimed at accessing the knowledge on the fundamental issues in diagnosis and treatment of community-acquired pneumonia. The survey involved 222 students in their fifth- and sixth years in medical institute from Belgorod, Dnepr (Dnipro), Voronezh, Kiev (Kyiv) and Saratov and 110 physicians from Krasnodar, Saratov, Belgorod and Dnepr.Results and discussion. According to the results of the survey, such levels of correct answers were given by doctors and students, respectively: the inadmissibility of antimicrobial therapy (AMT) delay in CAP - 82% and 59%; the main criterion for withholding AMT - 56% and 37%; “sequential therapy” - 61% and 59%. At the same time, only 24% of the students and 23% of the physicians surveyed correctly reported typical mistakes in the treatment of a non-severe CAP with 50% or more accuracy; and in case of initial treatment, the number of correct responses was less than 28% for students and 45% for doctors. Conclusion. The survey showed that both senior medical students majoring in Medical Care and general practitioners had a low level of knowledge in CAP treatment. Hence, curricula need to be adjusted both in medical universities and in health institutions for practitioners in order to inform them and, thus, improve the quality of their knowledge in this field

Assessment of physicians’ and senior medical students’ knowledge in treatment of patients with community-acquired pneumonia: Current results of the KNOCAP project

Community-acquired pneumonia (CAP) remains one of the most acute problems of bronchopulmonary pathology being the 4th in the mortality structure (after cardiovascular, cerebrovascular diseases and malignant neoplasms) and the 1st among all fatalities from infectious diseases. Thanks to the scientific progress achieved in the antibiotic therapy and vaccine prophylaxis, the death toll has decreased four times compared to its rate during the “pre-antibiotic era“. However, nowadays there is a steadily increasing trend in the pneumonia mortality rate in Russia. The only possible way to increase efficacy of CAP treatment is timely initiated rational antibiotic therapy, considering the possible etiologies, risk factors and the severity of the patient’s condition

Tandemly repeated DNA families in the mouse genome

<p>Abstract</p> <p>Background</p> <p>Functional and morphological studies of tandem DNA repeats, that combine high portion of most genomes, are mostly limited due to the incomplete characterization of these genome elements. We report here a genome wide analysis of the large tandem repeats (TR) found in the mouse genome assemblies.</p> <p>Results</p> <p>Using a bioinformatics approach, we identified large TR with array size more than 3 kb in two mouse whole genome shotgun (WGS) assemblies. Large TR were classified based on sequence similarity, chromosome position, monomer length, array variability, and GC content; we identified four superfamilies, eight families, and 62 subfamilies - including 60 not previously described. 1) The superfamily of centromeric minor satellite is only found in the unassembled part of the reference genome. 2) The pericentromeric major satellite is the most abundant superfamily and reveals high order repeat structure. 3) Transposable elements related superfamily contains two families. 4) The superfamily of heterogeneous tandem repeats includes four families. One family is found only in the WGS, while two families represent tandem repeats with either single or multi locus location. Despite multi locus location, TRPC-21A-MM is placed into a separated family due to its abundance, strictly pericentromeric location, and resemblance to big human satellites.</p> <p>To confirm our data, we next performed <it>in situ </it>hybridization with three repeats from distinct families. TRPC-21A-MM probe hybridized to chromosomes 3 and 17, multi locus TR-22A-MM probe hybridized to ten chromosomes, and single locus TR-54B-MM probe hybridized with the long loops that emerge from chromosome ends. In addition to <it>in silico </it>predicted several extra-chromosomes were positive for TR by <it>in situ </it>analysis, potentially indicating inaccurate genome assembly of the heterochromatic genome regions.</p> <p>Conclusions</p> <p>Chromosome-specific TR had been predicted for mouse but no reliable cytogenetic probes were available before. We report new analysis that identified <it>in silico </it>and confirmed <it>in situ </it>3/17 chromosome-specific probe TRPC-21-MM. Thus, the new classification had proven to be useful tool for continuation of genome study, while annotated TR can be the valuable source of cytogenetic probes for chromosome recognition.</p

Comparative Analysis of Two Models of the Two-Layer Fluid Motion by means of Ekman’s Approximation

Рассматриваются две модели экмановского типа для стационарного ветрового движения двухслойной жидкости, при этом верхний и нижний слои однородны, но имеют разные плотности. Для них найдены аналитические решения в двумерном и трехмерном случаях. В случае 2D считается, что дно неровное, а коэффициенты турбулентного обмена в верхнем и нижнем слоях зависят от глубины. В случае 3D считается, что дно ровное и коэффициенты турбулентного обмена постоянны в каждом слое. Найденные решения могут применяться для оценки положения линии раздела двух слоёв и в качестве тестов при отладке программ расчёта течений двухслойной жидкости.Two Ekman’s type models for stationary wind-driven motion of two-layer fluid are proposed. Upper and lower layers are homogeneous with different densities. The analytic solutions in the two-dimensional and three-dimensional cases are found for this models. For the 2-D case it is assumed that the bottom of the water basin is not flat and the vertical turbulent exchange coefficients in upper and lower layers depend on the depth. For the 3-D case the vertical turbulent exchange coefficients are constant in each layer and the bottom of the water basin is flat. The obtained solutions could be useful for the evaluation of the boundary location between layers and as a test in the analysis of computational algorithms which are applied for solving problem of the wind current in a two-layer liquid