Belarusian State Medical University

About: Belarusian State Medical University is a education organization based out in Minsk, Belarus. It is known for research contribution in the topics: Population & Medicine. The organization has 536 authors who have published 513 publications receiving 4635 citations.

HIV1 V3 Loop Hypermutability is Enhanced by the Guanine Usage Bias in the Part of env Gene Coding for it

Abstract: Guanine is the most mutable nucleotide in HIV genes because of frequently occurring G to A transitions, which are caused by cytosine deamination in viral DNA minus strands catalyzed by APOBEC enzymes. Distribution of guanine between three codon positions should influence the probability for G to A mutation to be nonsynonymous (to occur in first or second codon position). We discovered that nucleotide sequences of env genes coding for third variable regions (V3 loops) of gp120 from HIV1 and HIV2 have different kinds of guanine usage biases. In the HIV1 reference strain and 100 additionally analyzed HIV1 strains the guanine usage bias in V3 loop coding regions (2G>1G>>3G) should lead to elevated nonsynonymous G to A transitions occurrence rates. In the HIV2 reference strain and 100 other HIV2 strains guanine usage bias in V3 loop coding regions (3G>2G>1G) should protect V3 loops from hypermutability. According to the HIV1 and HIV2 V3 alignment, insertion of the sequence enriched with 2G (21 codons in length) occurred during the evolution of HIV1 predecessor, while insertion of the different sequence enriched with 3G (19 codons in length) occurred during the evolution of HIV2 predecessor. The higher is the level of 3G in the V3 coding region, the lower should be the immune escaping mutation occurrence rates. This hypothesis was tested in this study by comparing the guanine usage in V3 loop coding regions from HIV1 fast and slow progressors. All calculations have been performed by our algorithms "VVK In length", "VVK Dinucleotides" and "VVK Consensus" (www.barkovsky.hotmail.ru).

Local delivery of temozolomide via a biologically inert carrier (Temodex) prolongs survival in glioma patients, irrespectively of the methylation status of MGMT

Abstract: Glioma is the most common brain malignancy. Standard first-line therapy for glioma includes surgery, radiotherapy and systemic administration of temozolomide. However, temozolomide does not reach the brain in sufficient doses when administered orally and has poor efficiency in more than half of the patients. Strategies to improve the treatment of glial malignancies are therefore needed. We have recently developed a system (Temodex) for local administration of temozolomide by encapsulating the drug in a biologically inert matrix. Here, we assessed the effect of Temodex in combination with standard therapy in a small-scale clinical study. Since the efficacy of temozolomide therapy is known to depend on the methylation status of the O6-methylguanine-DNA methyltransferase gene (MGMT) promoter, we also analyzed whether the effect of Temodex was influenced by the methylation status of MGMT. Our data show that the combination of standard therapy and Temodex was more efficient than standard therapy alone, promoting the overall patient survival by up to 33 weeks. Moreover, the efficacy of Temodex was not dependent on the methylation status of MGMT. Local Temodex administration in combination with standard therapy thereby emerges as a novel therapeutic option, with applicability that is independent on the methylation status of the MGMT promoter.

Glycemic Allostasis during Mental Activities on Fasting in Non-alcohol Users and Alcohol Users with Different Durations of Abstinence.

Abstract: Glycemic allostasis is the process by which blood glucose stabilization is achieved through the balancing of glucose consumption rate and release into the blood stream under a variety of stressors.This paper reviews findings on the dynamics of glycemic levels during mental activities on fasting in non‑alcohol users and alcohol users with different periods of abstinence. Referred articles for this review were searched in the databases of PubMed, Scopus, DOAJ and AJOL. The search was conducted in 2013 between January 20 and July 31. The following keywords were used in the search: alcohol action on glycemia OR brain glucose OR cognitive functions; dynamics of glycemia, dynamics of glycemia during mental activities; dynamics of glycemia on fasting; dynamics of glycemia in non‑alcohol users OR alcohol users; glycemic regulation during sobriety. Analysis of the selected articles showed that glycemic allostasis during mental activities on fasting is poorly regulated in alcohol users even after a long duration of sobriety (1‑4 weeks after alcohol consumption), compared to non‑alcohol users. The major contributor to the maintenance of euglycemia during mental activities after the night’s rest (during continuing fast) is gluconeogenesis. Keywords : Abstainers, Abstinence, Alcohol, Alcohol users, Fasting, Glycemic allostasis, Mental activities, Sobriety

Changes in light sensitivity of the visual system with age and in patients with ischemic optic neuropathy

Abstract: OBJECTIVE To evaluate contrast-color sensitivity (CCS) of central vision, contrast-frequency sensitivity (CFS) and dynamic visual acuity (DVA) in healthy people and patients with ischemic optic neuropathy (ION) MATERIAL AND METHODS The study was performed for 115 eyes with normal static visual acuity (10) in 111 healthy people; 25 patients (39 eyes) with acute anterior ION and 26 patients (26 eyes) with chronic ION Assessment of static visual acuity and refraction as well as ophthalmoscopy of the eye fundus were performed RESULTS AND CONCLUSION Based on the data analysis of CFS, DVA and photometry of CCS, the quantitative estimation of age-related changing in light sensitivity and changing sensitivity of ill and healthy eyes of patients with acute and chronic ION has been carried out The differences between changing of these functional parameters are used for discussion of the role of age-related changes of visual system hemodynamics in decreasing of light sensitivity The possibility of usig the data of light sensitivity decreasing in the early diagnostics of visual system ischemic impairment is discussed