[Effect of exhaustive weightlifting exercise on EMG, biochemical markers of muscle damage and performance capacity in young male subjects].

The aim of this study was to examine the effect of exhaustive weightlifting exercise on electrical and biochemical variables and performance capacity in young male subjects. The onset of exercise (80-50% 1RM) was associated with a decrease in the amount of work performed, which was followed by a steady performance capacity at 40-10% 1RM. There were no significant changes of m. rectus femoris EMG maximal amplitude though it tended to be increased during the first half of exercise. A significant blood lactate concentration increase indicated that an anaerobic metabolism was a predominant mechanism of muscle contraction energy-supply. CK level in blood plasma did not change but plasma myoglobin concentration doubled immediately post-exercise. The data presented here suggest that decrease in performance capacity was likely due to progressive "refusal of work" of the fast motor units and work prolongation of weaker, intermediate and slow motor units. Unchangeable CK activity and relatively small increase in myoglobin concentration in plasma suggest that used weightlifting exercise did not induced substantial damage in myocytes' membranes in our subjects.

[Acute and remote biochemical and physiological effects of exhaustive weightlifting exercise].

The goal of the work was a study of exhaustive weightlifting exercise effect on prolonged changes in physiological and biochemical variables characterized functional status of skeletal muscles. An exercise gave rise to significant blood lactate concentration increase that was indicative of an anaerobic metabolism to be a predominant mechanism of muscle contraction energy supply. A reduction of m. rectus femoris EMG activity (amplitude and frequency), tonus of tension and an increase in tonus of relaxation were found immediately after exercise. Both EMG amplitude and frequency were increased 1 day post-exercise. However, after 3 days of recovery, EMG amplitude and frequency were decreased again and, in parallel, blood serum creatine kinase (CK) activity was significantly increased. After 9 recovery days, all measured variables with the exception of CK were normalized. A significant reverse correlation was found between blood serum lactate concentration and m. rectus femoris EMG activity at the same time points. Blood serum CK activity and m. rectus femoris EMG and tonus variables were observed to be significantly reversely correlated on the 3rd post-exercise day. Presented data demonstrate that exhaustive exercise-induced muscle injury resulted in phase alterations in electrical activity and tonus which correlated with lactate concentration and CK activity in blood serum.

[Evaluation of pepsinogen A expression in stomach cancer]. / Analiz ékspressii genov pepsinogena A pri rake zheludka.

The report deals with a molecular-genetic study of human pepsinogen A (PGA) genetic locus. EcoRI, HindIII and BamH 1 restriction endonuclease technique were employed. The investigation involving 58 patients with stomach cancer (SC) and 18 healthy donors failed to identify any significant PGA genetic restructuring in the blood of healthy donors. However, DNA sampled from tumor tissue showed lower expression and deletion of PGA fragments as compared with those of unaltered gastric mucosa in the same patients. Such changes were identified in 27 SC patients.

[Microsatellite instability of genome in cells of sporadic and hereditary carcinoma of the gastrointestinal tract]. / Mikrosatellitnaia nestabil'nost' genoma v kletkakh sporadicheskikh i nasledstvennykh kartsinom zheludochno-kishechnogo trakta.

Microsatellite instability (MIN) of human genome, i.e. instability of very short (1-5 nt) DNA tandem repeats, points to a deficiency in the mismatch repair system (MMR). To investigate the role of MMR in sporadic and hereditary carcinogenesis in the gastrointestinal tract, four types of carcinomas were compared: sporadic (GC), familial (FGC) gastric carcinoma, sporadic colorectal (CC) and hereditary nonpolyposis colorectal (HNPCC) carcinoma. No significant difference in MIN frequency was found between GC (9 out of 27) (33%) and CC (7 out of 29) (24%). In hereditary carcinoma group, MIN occurrence appeared 2-3 times as high: FGC in 7 out of 10 (70%) and HNPCC in 6 out of 8 patients (75%). No significant differences were recorded in MIN occurrence at early and later stages of the disease in all groups. Therefore, it can be suggested that disorders in the MMR develop at earlier stages of carcinogenesis and may be responsible for tumor progression.

Experimental gastrocarcinogenesis: the dynamics of morphological and biochemical changes.

In many cases of stomach disease, specific epithelial changes of the mucous membrane have already been detected and staged in the past. An attempt has been made in this study to assess with a more up-to-date approach the data concerning the possible molecular biological mechanisms of tumor proliferation in stomach epithelial cells.