THE EFFECT OF HYPOXIC BRAIN DAMAGE ON THE SURVIVAL OF PREMATURE INFANTS

The central nervous system injuries are a common neonatal pathology, hypoxia being one of the main causes of cerebral dysfunction. The purpose of this study was studying the incidence of hypoxic cerebral disorders in premature infants with an extremely low body weight and a very low birth weight and revealing the risk factors that adversely affected the disease outcome. The subject of the study was preterm infants whose gestational age did not exceed 31 weeks. The main criterion for inclusion into the study was the presence of hypoxic-ischemic and hypoxic-hemorrhagic brain damage. To reveal the perinatal risk factors, the somatic health of mothers, and pregnancy and childbirth peculiarities were studied. The structure of children’s pathology and intensive care techniques were analyzed. Cerebral disorders were verified in 42 out of 176 patients (23.5 %). 2–3rd-degree intraventricular hemorrhage was diagnosed in 34 newborns (80.9 %), severe ischemia in 8 children (19.1 %). To determine the structure of the disease outcome, all children were divided into deceased and survivors. A fatal outcome was observed in 14 cases (33.3 %). The mothers of deceased children were more likely to have obstetric and concomitant extragenital pathologies. Analysis of pediatric pathology showed that the hemodynamically significant functioning arterial duct and severe asphyxia in childbirth were much more frequent in deceased children. Intensive therapy of deceased children included «hard» parameters of artificial ventilation and high doses of cardiotonic drugs. Thus the presented risk factors can be considered as predictors of an unfavorable outcome in children with this pathology

Upper limits on the isotropic diffuse flux of cosmic PeV photons from Carpet-2 observations

Isotropic diffuse gamma-ray flux in the PeV energy band is an important tool for multimessenger tests of models of the origin of high-energy astrophysical neutrinos and for new-physics searches. So far, this flux has not yet been observed. Carpet-2 is an air-shower experiment capable of detecting astrophysical gamma rays with energies above 0.1 PeV. Here we report the upper limits on the isotropic gamma-ray flux from Carpet-2 data obtained in 1999-2011 and 2018-2022. These results, obtained with the new statistical method based on the shape of the muon-number distribution, summarize Carpet-2 observations as the upgraded installation, Carpet-3, starts its operation.Comment: 5 pages, 3 figures, JETPL.cls; V2: references added, version accepted by JETP Letter

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

60 лет Стоматологическому факультету ПСПбГМУ им. И. П. Павлова

60th anniversary of the Faculty of Dentistry of Pavlov University.История стоматологии в России неразрывно связана с Петроградом – Ленинградом – Санкт-Петербургом. Первые зубные врачи появились в Петербурге, первая школа зубоврачевания появилась в Петербурге, один из первых стоматологических институтов в СССР появился в Ленинграде, один из крупнейших стоматологических факультетов в СССР с всероссийским распределением выпускников появился в Ленинграде. В 1899 году в Женском медицинском институте (в будущем 1ЛМИ) была создана первая кафедра одонтологии (стоматологии) в России, которую возглавил первый профессор-стоматолог России Александр Карлович Лимберг. В 1886 году он зачисляется на службу в Императорское человеколюбивое общество. В мае 1891 года защищает диссертацию на степень доктора медицины «Современная профилактика и терапия костоеды зубов». Огромная заслуга А.К. Лимберга заключается в том, что ему удалось обосновать необходимость высшего медицинского образования для зубных врачей и добиться положительного решения в министерстве народного просвещения. С этого времени повысился уровень практической подготовки зубных врачей, и проблемы одонтологии получили достойное научное развитие. Сегодня стоматологический факультет 1-го ЛОТКЗМИ им. акад. И.П. Павлова (1-го Ленинградского Ордена Трудового Красного Знамени медицинского института имени академика И.П. Павлова), теперь Первого Санкт-Петербургского государственного медицинского университета имени академика И.П. Павлова отмечает свой юбилей – 60 лет в строю. Это те вехи, которые прошел стоматологический факультет за годы своего существования.Авторы заявили об отсутствии потенциального конфликта интересов.Авторы подтверждают, что соблюдены права людей, принимавших участие в исследовании, включая получение информированного согласия в тех случаях, когда оно необходимо, и правила обращения с животными в случаях их использования в работе. Подробная информация содержится в Правилах для авторов

Minimum Criteria for DNA Damage-Induced Phase Advances in Circadian Rhythms

Robust oscillatory behaviors are common features of circadian and cell cycle rhythms. These cyclic processes, however, behave distinctively in terms of their periods and phases in response to external influences such as light, temperature, nutrients, etc. Nevertheless, several links have been found between these two oscillators. Cell division cycles gated by the circadian clock have been observed since the late 1950s. On the other hand, ionizing radiation (IR) treatments cause cells to undergo a DNA damage response, which leads to phase shifts (mostly advances) in circadian rhythms. Circadian gating of the cell cycle can be attributed to the cell cycle inhibitor kinase Wee1 (which is regulated by the heterodimeric circadian clock transcription factor, BMAL1/CLK), and possibly in conjunction with other cell cycle components that are known to be regulated by the circadian clock (i.e., c-Myc and cyclin D1). It has also been shown that DNA damage-induced activation of the cell cycle regulator, Chk2, leads to phosphorylation and destruction of a circadian clock component (i.e., PER1 in Mus or FRQ in Neurospora crassa). However, the molecular mechanism underlying how DNA damage causes predominantly phase advances in the circadian clock remains unknown. In order to address this question, we employ mathematical modeling to simulate different phase response curves (PRCs) from either dexamethasone (Dex) or IR treatment experiments. Dex is known to synchronize circadian rhythms in cell culture and may generate both phase advances and delays. We observe unique phase responses with minimum delays of the circadian clock upon DNA damage when two criteria are met: (1) existence of an autocatalytic positive feedback mechanism in addition to the time-delayed negative feedback loop in the clock system and (2) Chk2-dependent phosphorylation and degradation of PERs that are not bound to BMAL1/CLK

Intestinal Microbiota Regulate Xenobiotic Metabolism in the Liver

BACKGROUND: The liver is the central organ for xenobiotic metabolism (XM) and is regulated by nuclear receptors such as CAR and PXR, which control the metabolism of drugs. Here we report that gut microbiota influences liver gene expression and alters xenobiotic metabolism in animals exposed to barbiturates. PRINCIPAL FINDINGS: By comparing hepatic gene expression on microarrays from germfree (GF) and conventionally-raised mice (SPF), we identified a cluster of 112 differentially expressed target genes predominantly connected to xenobiotic metabolism and pathways inhibiting RXR function. These findings were functionally validated by exposing GF and SPF mice to pentobarbital which confirmed that xenobiotic metabolism in GF mice is significantly more efficient (shorter time of anesthesia) when compared to the SPF group. CONCLUSION: Our data demonstrate that gut microbiota modulates hepatic gene expression and function by altering its xenobiotic response to drugs without direct contact with the liver