Evaluation of folliculogenesis and oxidative stress parameters in type 1 diabetes mellitus women with different glycemic profiles.

BACKGROUND: Despite enormous advances in diabetes treatment, women with type 1 diabetes mellitus (DM) still experience delayed menarche, menstrual irregularities, fewer pregnancies, and a higher rate of stillbirths compared to women without the disease. Due to the fact that type 1 DM occurs at a young age, the preservation of reproductive health is one of the most important goals of treatment. AIMS: The aim of this study was to evaluate the relationship between different glycemic profiles and changes in the pro-oxidant-antioxidant balance and ovarian follicular apparatus in reproductive-age patients with type 1 DM. METHODS: We examined 50 reproductive-age (19-38 years) women with type 1 DM with a disease duration of at least ten years. Carbohydrate metabolism was assessed with the continuous glucose monitoring (CGM) system and glycated hemoglobin (HbA1c) concentration measurement. CGM was performed using the FreeStyle Libre flash glucose monitoring system (Abbott Diabetes Care, Witney, UK). In each patient, malondialdehyde level, catalase activity and 3-nitrotyrosine level in the blood serum were determined. To assess the ovarian function, we measured the ovarian volume, the antral follicle count, and the serum levels of anti-Müllerian hormone and follicle-stimulating hormone. All patients were divided into four groups (glucotypes) based on the CGM results. Group 1 included type 1 DM patients with satisfactory compensation of carbohydrate metabolism; group 2 consisted of patients with frequent hypoglycemic conditions and pathological glucose variability; group 3 included individuals with prolonged hyperglycemic conditions and maximum HbA1c levels; and group 4 comprised patients with the glycemic profile characterized by all the presented types of dysglycemia (intermittent glycemia). RESULTS: We revealed a negative correlation between serum catalase activity and time of hypoglycemic conditions in patients with type 1 DM based on the CGM results (rs = -0.47, p < 0.01). In group 4 (intermittent glycemia), patients demonstrated the lowest serum catalase activity and increased serum 3-nitrotyrosine level, while in group 3, women with chronic hyperglycemia (HbA1c 8.4 [8.1; 9.9]%; 68 [65; 85] mmol/mol) had a moderate change in antioxidant defense and oxidative stress parameters. Correlation analysis of ovarian volume, the antral follicle count, and the serum anti-Müllerian hormone level in type 1 DM women with different glycemic profiles established a negative relationship (rs = -0.82, p < 0.05) between the antral follicle count and glucose variability in group 1, a positive relationship (rs = 0.68, p < 0.05) between ovarian volume and glucose variability in group 2, and a positive relationship (rs = 0.88, p < 0.05) between ovarian volume and time of hypoglycemic conditions, which, according to the CGM results, amounted to a critical value of 57.5 [40.0; 82.0]%. CONCLUSIONS: The data obtained indicate the relationship between the ovarian volume, serum anti-Müllerian hormone level, the antral follicle count and oxidative stress parameters not only in patients with hyperglycemia, but also in those with hypoglycemic conditions, as well as with pathological glucose variability.

[The influence of hyperhomocysteinemia on monoaminoergic systems of hypothalamus and hippocampus of female rats at aging].

The data presented have shown the different effect of hyperhomocysteinemia (induced by 0,12-0,15 mg of methionine loading per os during 30 days) on monoamines content in hypothalamus and hippocampus of young (6-7 month) and old (20-22 month) female rats. It has been established that the level of catecholamines (noradrenaline, dopamine), 5 oxitryptamine and 5 oxyindolacetic acid in hypothalamic areas responsible for synthesis and secretion of gonadoliberin (medial preoptic area and medial eminence with arcuate nuclei) is considerable less in old animals compared with young ones. These data are in agreement with the low content of gonadoliberin found by us in medial eminence with arcuate nuclei. It has been also shown the decreased level of monoamines level in hippocampus of old rats, which does not depend on methionine loading. However in hippocampus of young animals hyperhomocysteinemia induced a noticeable reduction of noradrenaline and 5 oxyindolacetic acid, which can lead to weakening of animal's cognitive function.

[Protective effect of melatonin and epithalon on hypothalamic regulation of reproduction in female rats in its premature aging model and on estrous cycles in senescent animals in various lighting regimes].

Potential neuroprotective effects of the pineal gland hormone melatonin and peptide preparation epitalon on estrous cycles and the central regulation of reproduction in female rats exposed to unfavourable environmental factors have been studied. Estrous cycles of young, mature and aging rats exposed to light pollution were described. The diurnal dynamics and daily mean content of biogenic amines in the hypothalamic areas responsible for gonadotropin-releasing hormone synthesis and secretion in animals of different age groups were investigated. An effect of a chemical factor on the noradrenergic system of the medial preoptic area and on the dopaminergic system of the median eminence with arcuate nuclei of the hypothalamus was studied in premature aging of reproduction model. Administration of the pineal gland peptide melatonin and peptide preparation epitalon was shown to be able to correct a number of impairments of the hypothalamic-pituitary-gonadal axis that can be observed, when the experimental animals were exposed to permanent artificial lighting and a neurotoxic xenobiotic 1,2-dimethylhydrazine. The data obtained testify to an important role of the pineal gland in the circadian signal formation needed for gonadotropin-releasing hormone in order to exert its preovulatory peak secretion and to the protective effect of melatonin and epitalon, which are able to reduce unfavourable environmental influences on reproduction of young and aging female rats.

Redox-reactive membrane vesicles produced by Shewanella.

This manuscript is dedicated to our friend, mentor, and coauthor Dr Terry Beveridge, who devoted his scientific career to advancing fundamental aspects of microbial ultrastructure using innovative electron microscopic approaches. During his graduate studies with Professor Robert Murray, Terry provided some of the first glimpses and structural evaluations of the regular surface arrays (S-layers) of Gram-negative bacteria (Beveridge & Murray, 1974, 1975, 1976a). Beginning with his early electron microscopic assessments of metal binding by cell walls from Gram-positive bacteria (Beveridge & Murray, 1976b, 1980) and continuing with more than 30 years of pioneering research on microbe-mineral interactions (Hoyle & Beveridge, 1983, 1984; Ferris et al., 1986; Gorby et al., 1988; Beveridge, 1989; Mullen et al., 1989; Urrutia Mera et al., 1992; Mera & Beveridge, 1993; Brown et al., 1994; Konhauser et al., 1994; Beveridge et al., 1997; Newman et al., 1997; Lower et al., 2001; Glasauer et al., 2002; Baesman et al., 2007), Terry helped to shape the developing field of biogeochemistry. Terry and his associates are also widely regarded for their research defining the structure and function of outer membrane vesicles from Gram-negative bacteria that facilitate processes ranging from the delivery of pathogenic enzymes to the possible exchange of genetic information. The current report represents the confluence of two of Terry's thematic research streams by demonstrating that membrane vesicles produced by dissimilatory metal-reducing bacteria from the genus Shewanella catalyze the enzymatic transformation and precipitation of heavy metals and radionuclides. Under low-shear conditions, membrane vesicles are commonly tethered to intact cells by electrically conductive filaments known as bacterial nanowires. The functional role of membrane vesicles and associated nanowires is not known, but the potential for mineralized vesicles that morphologically resemble nanofossils to serve as palaeontological indicators of early life on Earth and as biosignatures of life on other planets is recognized.

Disturbances of diurnal rhythms of biogenic amines contents in hypothalamic nuclei as an evidence of neurotropic effects of enterotropic carcinogen 1,2-dimethylhydrazine.

OBJECTIVES: Our data on the contents of norepinephrine (NE), dopamine (DA) and the metabolite of serotonin 5-hydroxyindoleacetic acid (5-HIAA) measured in the suprachiasmatic nuclei (SCN), preoptic area (PA) and median eminence (ME) of hypothalamus of rats after single subcutaneous injection of 1,2-dimethylhydrazine (DMH) as well as the effect of this carcinogen on formation of reactive oxygen species (ROS) in the PA are presented in this paper. RESULTS: Diurnal changes of DA in all studied brain structures and of NE in the PA have been observed in the control group. Their morning levels were higher than evening ones. Rhythms of 5-HIAA in the SCN and diurnal changes of ROS formation have been shown to have contrary changes in control. Both the morning (11 a.m.) and evening (11 p.m.) subcutaneous administration of DMH at the dose of 21 mg/kg of body weight resulted in changes of all rhythms observed in control. In some cases a phase shift was found, in others the rhythms of neurotransmitters and ROS formation disappeared entirely. CONCLUSION: The data obtained confirm the idea of dopaminergic and serotoninergic systems taking part in mechanisms of a response of the hypothalamic nuclei to non-photic stimuli. It is suggested that the effect of DMH on the content and diurnal rhythms of neurotransmitters in the hypothalamic structures under study is due to its affecting activities of the enzymes of biogenic amines synthesis, synaptic transmission, melatonin synthesis and secretion rhythms. The change in ROS formation that is caused by administration of DMH is likely to be due to a disturbance of diurnal rhythms of neurotransmitters that are one of the sources of formation of free radicals in the brain.