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We study parametric down-conversion (PDC) of optical laser radiation in the strongly frequency non-degenerate regime which is promising for the generation of quantum-correlated pairs of extremely different spectral ranges, the optical and the terahertz (THz) ones. The possibility to detect tenuous THz-frequency photon fluxes generated under low-gain spontaneous PDC is demonstrated using a hot electron bolometer. Then experimental dependences of the THz radiation power on the detection angle and on the pump intensity are analyzed.

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AIM: To study the effectiveness of respiratory hypercapnic-hypoxic training in complex treatment of neuropathy due to diabetes type 1. MATERIAL AND METHODS: Fifty children, 31 girls and 19 boys, were examined. The inclusion criteria were the presence of polyneuropathy, verified on the basis of clinical data and electromyographic changes. The patients were divided into 2 groups: the main group (n=25, 15 girls and 10 boys, mean age 12.9±1.8 years (M±SD) and the comparison group (n=25, 16 girls and 9 boys, mean age 13.2±2.0 years). Patients of the main group, along with standard therapy received respiratory hypercapnic-hypoxic training. RESULTS: The positive clinical and neurophysiological dynamics was noted in both groups, with more significant changes in children after respiratory training. CONCLUSION: Hypercapnic exercises significantly contribute to the pathogenetic therapy of diabetes mellitus and polyneuropathy in this disease, have a significant clinical effects reducing serum concentrations of fasting glucose and severity of neurological deficit scores on the NIS-LL, increasing the speed of conduction of excitation through the nerves, reducing the residual latency of EMG activity.

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The effects of mexidole on the higher efficiency of treatment for diseases involving the visual nerve apparatus and on the achievement of stable visual function were studied in children. The study covered a study group of 36 children aged 5 to 12 years (mean 8.50 +/- 0.56 years) who had amblyopla of various genesis. A control group comprised 30 patients (mean age was 8.20 +/- 0.56 years) who had also amblyopia of various genesis and 25 healthy children (mean age was 8.20 +/- 0.63 years). The patients of the first two groups received the similar course pleoptic treatment. Those of the study group were additionally given mexidole by the conventional regimen. Mexidole used in children with amblyopia enhanced the efficiency of complex pleoptic treatment in 83% of cases and long maintained the visual functions achieved during stimulation. The agent has a positive effect on the values of visually evoked potentials.

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There was an examination of 20 patients (12 women and 8 men), aged 30 to 50, with TMJ dysfunction and with partial absence and abrasion of teeth with decrease in the height of the lower facial part and distal mandible shift, and of 12 people (7 women and 5 men), aged 20 to 40, with intact dentitions using electromyography of masticatory muscles and computer tomography, followed by evaluation of the optical density of mandibular head. Analysis of the results enabled to determine the presence of disorders of the balanced activity of masticatory muscles and enables to determine alterations in the optical density of mandibular head. It is necessary to consider the obtained data in planning the prosthetic treatment and preparation of the mouth for prosthetics of patients with TMJ pathology.

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Visual evoked potentials (VEP) in response to reverse chess patterns were studied in 68 patients aged 7-14 years with pathological convolutions of internal carotid arteries and 25 healthy children. The latent period was increased and the amplitude of P100 peak decreased in the patients, which was indicative of dysfunction of the visual route. VEP changed at early stages of cerebral circulation insufficiency. The relationship between hemodynamic parameters and VEP values was proven. Increased latent period and decreased amplitude of the positive peak are the criteria of neurophysiological significance of pathological convolutions in the internal carotid arteries.

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The science suffered a severe loss with the sudden death in November 2, 1991, of and outstanding physiologist Academician Alexander Mikhailovich Ugolev at the age of 66. All life of this man was devoted to the development of the national science. It was the aim and meaning of his life, he has contributed to scientific progress in every possible way. The major scientific interests of A. M. Ugolev were focused on the basic and applied areas of food assimilation, including the physiology of nutrition and digestion. The works of the scientist in this field of knowledge were world-wide recognized. During his scientific activity Dr. Ugolev conducted a number of brilliant studies which remained unforgettable trace in physiology and for ever will be a part of golden fund of science. This was promoted by a unique combination of his illustrious abilities of physiologist and general biologist as well as evolutionist with the gift of experimenter and excellent surgeon. His experimental skill can serve and example of an elegant combination of bold intentions and their masterly realizations. But the most remarkable and world-wide recognized discovery of the scientist was that of membrane digestion--previously unknown mechanism of food assimilation. Just this basic discovery is emphasized in the review devoted to the memory of unforgettable master. The fragmentariness of material depends on a desire to present concisely the major characteristics of membrane digestion.

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In space flights of various duration, the gastropancreatic complex turned out to be the most liable part of the digestive system. The main changes occurring in the gastrointestinal tract involve an increase in the peptic gastric potential, pancreatic hyperenzymemia, change of the glycemic curve forms, a decrease in the liver and pancreas density.

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The article presents an evaluation of the state of the digestive system in astronauts during short-term and long-term space flights. After short-term (7- or 8-day) flights, there was a transitory activation of gastrointestinal enzyme systems. After prolonged space flights, there was an increase in gastric acidity and pepsin excretion, as well as pancreatic and intestinal malfunctions. In summary, there is a transition of the digestive system to a new level of functioning.

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Numerous studies have revealed changes in gastrointestinal secretion, motility, evacuation, and absorption in humans and animals after actual space missions and under hypokinesia of various duration as well. It is found that short-term space missions produce transient changes in the activity of digestive enzymes, instability of bifido- and lactoflora peculiar to stress reaction, and an enhanced evacuation of the stomach. Extended space missions result in more pronounced but transient changes which characterize mainly two states: development of a hypersecretory syndrome of the stomach and decrease in the functional capacity of the pancreas. As a rule, the changes of membranous enzymes are of compensatory-and-adaptive character. Concurrent with this, there occur disbiotic changes of various degree in the intestinal microflora.

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Carbohydrate hydrolysis, transport and utilization were investigated in rats exposed to diminished motor activity for 90 days. Glycemic curves were examined using provocative tests with equivalent quantities (1.5 g/kg body weight) of poly-, oligo- and monosaccharides (starch, maltose, glucose). Simultaneously, carbohydrases were measured in the homogenates of the pancreas, duodenal mucosa and small intestine as well as radioimmune insulin and glucagon were determined in blood. In the course of hypokinesia carbohydrate hydrolysis, transport and utilization varied in a different manner. At the beginning of exposure the activity of carbohydrases responsible for carbohydrate hydrolysis in the cavity and membranes increased which was accompanied by hyperglycemia and rapid utilization of carbohydrates. This is associated with nonspecific reactions to hypokinesia and higher requirements of the body for the energy substrate. By hypokinesia day 30 carbohydrate hydrolysis and transport were inhibited, hypoglycemia developed but glucose utilization remained unchanged. At a later stage of exposure the system of carbohydrate hydrolysis and transport showed an adaptive reaction; inhibition of pancreatic amylase was accompanied by accelerated enzyme transport in the small intestine and glucose resorption. In this situation the glycemic curves became extended suggesting a delay in glucose utilization. The latter was induced by changes in the endocrine compartment of the pancreas.

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The spectrum of bile acids and bile lipids in men exposed to 120-day head-down tilt was investigated. The test subjects were subdivided in to four groups: group 1-bed rest per se, group 2-bed rest + exercise, group 3-bed rest + drugs normalizing calcium metabolism, and group 4-bed rest + exercise + drugs. It was anticipated that biliary concrements would primarily be formed in group 1 and 2 subjects. They showed a low level of bile acids and a high content of total Ca and cholesterol in the bile, which was more pronounced in the C portion (decrease of the cholate/cholesterol coefficient). Group 2 subjects displayed a modified synthetic function of the liver: prevalence of tauroconjugates in the bile (decrease of the ratio of glucoconjugates to tauroconjugates). Group 3 and 4 subjects showed a faster synthesis of bile acids in the liver and a lower content of total calcium and cholesterol in the bile, the latter being more distinct in group 4 subjects. Positive dynamics of these parameters is a factor responsible for a reduced lithogeny of the bile. However, the test subjects of these groups exhibited hazardous changes that may be responsible for concrement formation. This is indicated by a lower concentration of the lipid complex in the bile, possibly at the expense of a lower content of phospholipids. This emphasizes the necessity of further search for prophylactic procedures aimed at normalizing the synthetic function of the liver under hypokinetic conditions.

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Twenty one test subjects exposed to head-down tilt for 120 days were subdivided to four groups: Group 1--nine subjects used as controls, Group 2--three bed rested subjects who performed regular exercises, Group 3--four bed rested subjects who were given selected drugs, including Vitamin F-99 that influenced lipid metabolism, and Group 4--four bed rested subjects who performed regular exercises and received Vitamin F-99. At different stages of bed rest and recovery the content of lipoprotein fractions and lipids of different classes in serum was measured by thin-layer chromatography. The concentration of cholesterol in biliary lipids was determined. In Group 1 and 2 subjects bed rest led to a drastic and significant increase of cholesterol esters in blood, a decrease of phospholipids, variations of triglycerides and non-esterified fatty acids, and a lower percentage content of alpha-lipoproteins. The use of Vitamin F-99 produced positive changes in the above parameters of lipid metabolism (it normalized the level of cholesterol and phospholipids). In Group 4 subjects the effect of exercise combined with drugs was most distinct.

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Full-value diets of similar composition were given to male rats weighing 207-230 g, by intravenous (group 1) or intragastric (group 2) routes. The proportion of amino acids, fats and carbohydrates was 9.9:15.7:74.4 (with regard to their calorific value). The diet calorific value comprised 60.6 kcal/rat/day. An average mass increase in group 1 was 2.44 +/- 0.14 g/day, in group 2 - 1.75 +/- 0.11 g/day. The protein content and activities of alpha- and gamma-amylase, invertase, maltase, and glycil-L-leucine dipeptidase were assayed in the intestinal mucosa of the proximal portion of the small intestine in group 1 rats, while a decreased alpha-amylase activity in the distal portion of the small intestine was recorded in the animals of group 2. The mass of the pancreas in the rats of group 1 and 2 was authentically lower than in the control rats which received oral feeding with natural foods. The lowest mass of the pancreas was observed in the rats of group 1. Specific activity of trypsin, lipase and RNase in the pancreatic tissues of rats in groups 1 and 2 was similar. The results of the study have evidenced a lowered function of the digestive system under conditions of artificial feeding, especially in case of intravenous nutrition.

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