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Biomedical subjects

L Lyhs

Publications and source records attributed to L Lyhs.

At least 19 recordsLinked to original sources

[Neural regulation of food absorption--review].

The periodical food intake (discrete meals) demands a control system, which includes signals for hunger and satiety. Satiety and hunger change with the absorptive and postabsorptive state of the delivery of nutrients to the organism. The brain areas involved in the regulation of food intake receive informations from three sources: periphery, environment and memory. Hypothalamic structures and pathways of neurotransmitters are considered especially. Beside these, the limbic structures are mainly responsible for the development of motivated feeding behaviour. Disturbances in the regulation of feeding behaviour are prone to cause obesity and anorexia nervosa.

Animals

[Interaction between the central nervous system and the immune system--review].

Results of research within the last years suggest that although the immune system has an autonomous regulation, it is nevertheless subject to control and regulation by the central nervous system. Likewise the central nervous system receives many informations from the immune system. There is a complete regulatory circle between both systems. Disturbances in one system cause changes in the other system. The mechanisms of mutual influences are described and their importance in the pathogenesis of diseases and disturbances of functions are discussed.

Central Nervous System

[Use of infrared technic in veterinary medicine. (Review)].

More effectiveness of veterinary examination of the living animal is an important demand of socialist practice which applies equally to conditions of stepwise transition to industrialised production processes and to conventional production. The physiological and physico-technical prerequisites for possible use of infrared techniques in veterinary attention and production monitoring are discussed on the basis of available literature, with particular reference being made also to human medicine.

Animal Diseases

[Blood acid-base status in fattening pigs in exhausting physical stress of high intensity].

Reported in this paper are changes in the acid-base state and lactic concentration of blood and muscle samples taken from 28 pigs prior to, during, and after high-intensity exhausting stress applied at ambient temperatures between 17 degrees C and 21 degrees C and at 35 degrees C. Close correlations were found to exist between acid-base states, on the one hand, and lactic acid concentrations, on the other. The lactic acid concentrations reached in blood plasma were between 30 and 40 mHol/1, pH being below 7.0 and BE values being smaller than -22 mHol/1. Close relationships were established between the lactic acid concentration of venous blood plasma, blood pH, and the pH of the musculus longissimus dorsi. Respiratory compensation was of minor importance with ambient temperatures between 17 degrees C and 21 degrees C, but it was of considerable effectiveness at 35 degrees C.

Acid-Base Equilibrium

[Reactions of the domestic pig to exhausting motor stress of middle intensity].

The VO 2max value was established from twelve pigs, followed by checks of their responses to endurance stress (walk 0.7 m/sec, ambient temperatures between 22 degress C and 24 degrees C, relative humidities between 67 and 78 per cent). Also measured were the rectal temperature, heart rate, respiratory rate, haemoglobin level of the blood, haematocrit, mean corpuscular haemoglobin concentration, plasma volume, blood volume, total haemoglobin, plasma glucose concentration and plasma lactid acid concentration. A differentiation could be made between one group weighing between 53.3 +/- 2.47 kg and enduring 97 +/- 9 minutes and another weighing 60.0 +/- 1.38 kg and enduring 36 +/- 6 minutes. The two groups differed from one another for their plasma and blood volumes, their values being 42.6 +/- 3.8 ml/kg and 67.5 +/- 7.5 ml/kg or 33.5 +/- 3.4 ml/kg and 52.2 +/- 5.9 ml/kg. The groups produced quantitatively different responses to endurance stress. The demands implied in endurance were widely met by the circulatory system, while the energy transfer was characterised primarily by aerobic energy collection.

Animals

[Glucocorticosteroid, catecholamine and protein-bound iodine (PBI) plasma levels in swine following electrocutaneous stimulation].

Application of electrocutaneous stimuli for short-time excitation of swine, accompanied by high locomotor activity, led in animals weighing between 30 kg and 45 kg to steep rises of catecholamine and glucocorticosteroid plasma concentrations, while little change was recordable from protein-linked iodine. Increase in plasma glucose and RQ in animals with higher rises in plasma-borne catecholamines and glucocorticoids was higher than that in animals with lower catecholamine deflection. Both the results reported in this paper and findings obtained from other studies into swine are likely to suggest major involvement of the sympathico-adrenomedullary system in the buildup of transport stress. Interdependence was found to exist between the intensity of the adrenergic reaction, on the one hand, and rises in plasma glucose and RQ as well as drop of pH, on the other. Those findings from various tests seem to support the conclusion that under conditions of severe excitation and high locomotor activity the differentiated resistance of swine to stress is atributable to different intensities of sympathico-adrenergic reaction of the animal concerned.

11-Hydroxycorticosteroids

[Acid-base status in the blood of domestic pigs during exhausting locomotor stress of small and medium intensity].

Twenty-two fattening pigs were stressed until their rectal temperatures had reached 42 degrees C. The means of stress included walking on moving conveyor belt at ambient temperatures between 22 degrees C and 27 degrees C and relative humidities between 69 and 98%, belt speeds of 0.7 m/s, 1.3 m/s or 0.7 m/s, and stimulation by means of a forcing rod. Rectal temperature, respiratory frequency, lactic acid level in blood plasma, pH, as well as pCO2 and base excess in the blood were measured prior to, during, and after stressing. Gasping was strongly pronounced due to severe alkalisis, but it was somewhat mitigated on running on the belt with exposure to additional stress on account of lactic acid accumulation in the plasma.

Acid-Base Equilibrium

[Influence of blood volume drain on some factors of circulation in rabbit].

Blood volume were drained from 20 female rabbits, all White New Zealanders, 2.5 kg in average body weight. Several factors of their circulation were determined twice, prior to and after the blood volume withdrawals. Included in the tests were haematocrit, haemoglobin, plasma volume by means of Evans blue dye dilution technique, and blood volume. The amounts of blood volume, BV0, drained ten, 20, 40, 60, and 70 minutes after beginning of the experiment were 4.4, 6.7, 8.9, 11.2, and 13.4 per cent. The ambient temperature was 15 degrees C and the relative humidity 60 per cent. The haematocrit value dropped to 91.2 per cent of the original figure over the whole experimental period and haemoglobin to 87.5 per cent, but decline of the latter was of minor importance along with blood volume loss from 8.9 per cent to 11.2 per cent BV0. Blood volume drain of 8.9 per cent BV0 was accompanied by 102.04 per cent plasma volume, PV0, and 100.4 per cent BV0. Erythrocyte volume and total haemoglobin exhibited similar behaviour in connection with the above amount of blood drain and did not return to their original values. Rabbit response to blood loss (re-absorption of fluid and splenic depletion) is discussed.

Animals

[Reactions of European wild boars (Sus scrofa scrofa L.) to running stress. 1. Behavior of respiratory and heart rate as well as the rectal temperature in standard tests of varying intensity and duration].

Eight wild boars, aged between twelve and six months and weighing between 81 kg and 39 kg, all kept on floor surfaces and diets used also for domestic pigs, were exposed on a horizontally operated belt to three locomotor stresses which differed by intensity and duration. The speeds were 78 m/min in tests A and C and 138 m/min in test B. The time was limited to ten minutes in test A and 40 minutes in test C, whereas in test B the animals were kept running their rectal temperature had gone up to 41.5 degrees C. Rectal temperature, heart rate, respiratory frequency, as well as the electric diastole-systole quotient were measured in each of the tests. Described are the effects of both intensity and duration in terms of disturbance of the physiological equilibrium. The response produced by wild boar were compared with those recorded from domestic swine and yielded only slight superiority in physical fitness of wild boar.

Animals

[Reactions of European wild boars (Sus scrofa scrofa L.) to running stress. 2. Circulation values, blood glucose and lactates and blood acid-base status].

Four female and four male wild boars, 63.8 +/- 4.43 kg in live weight, were exposed to locomotor stress on a horizontally operated belt set to a speed of 2.5 m/s for ten minutes. The ambient temperatures were between 12 degrees C and 18 degrees C and the relative humidities between 55 and 75%. The following parameters were measured prior to, during, and after the stress tests: rectal temperature, haemoglobin level, haematocrit, plasma and blood volumes, total haemoglobin levels, lactic acid and glucose levels in blood plasma, pH, pCO2, and excess base. Rectal temperatures went up continuously. Haemoglobin levels, blood volumes, haematocrit values, and total heamoglobin were increased due to the mobilisation of erythrocytes from the spleen. The plasma volume remained constant. Lactic acid went up at the beginning of the stress run and declined during running. Respiratory alkalosis occurred in the context of the acid-base state prior to, towards the end, and even more after stressing.

Acid-Base Equilibrium

[Plasma concentration curves of catecholamines and corticosteroids as well as PBI in swine kept under various conditions and acutely exposed to cold].

The response to acute cold (-5 degrees C) of swine kept single was found to differ from that of animals kept in groups. Such difference in reaction was reflected in significant variation of plasma concentration curves in catechol amines and 11-OHKS during and after acute exposure to cold. The response to cold stimulation of animals kept single was primarily and pronouncedly via the sympathicoadrenal system, whereas animals kept in groups responded to acute cold exposure, with the hypothalamic-adrenocortico-pituitary system playing the major role. Significant rise in PBJ in response to 30 and 90 minutes of exposure to cold was recorded only from animals kept single and interpreted as an expression of strong adrenergic reaction of such probands. Such difference in response to one and the same acute stimulus supported the conclusion that there was a difference in adaptation capacity between animals in those two keeping conditions. The results also suggested that type and degree of organic response to a specific stimulus were likely to depend not only on the intensity of the given stimulus, but also on the control potential produced by all closely interconnected control circuits at the time of stimulation.

Adrenal Cortex Hormones

[Effect of noise on the physiological functions in fowl. 1. Effect of primary strong noise on the 11-OHKS level in broilers and leghorns].

The effects of first noises on broilers and white leghorns were tested by plasma levels on 11-hydroxycorticosteroid (11-OHKS). The noises were 100 dB, 60 to 8,00 Hz, and applied 30 minutss to one group of broilers, aged 14, 28, and 56 days, and to another group of broilers and white leghorns in adult age. The reactions were compared. Acoustic stimulation was followed by temporary activation of the hypothalamic pituitary-suprarenal system. The rise of the plasma glucocorticosteroid level in leghorns was three times as high as that in adult broilers, which was interpreted as a reflection of stronger organic stress. Reactions differed in intensity, depending on age as well. Plasma-11-OHKS levels went up by 32 per cent maximum in broilers aged 56 days or by 73 per cent in animals aged 14 days or 120 per cent in those aged 28 days. The above results seemed to support the conclusion that noises of the above quantity and quality represented stress on fowl.

11-Hydroxycorticosteroids

[Effect of noise on the physiological functions in fowl. 2. Adaptation to noise of white leghorns and broilers].

Two experimental groups and series were compared (leghorns and broilers as well as two age groups of broilers) for their adaptive responses to repeated noise application. The noise was 100 dB and applied daily 30 minutes. The reference for comparison was the plasma-11-hydroxycorticosteroid concentration (11-OHKS). The results differed somewhat from those obtained earlier from one first short-time noise application, in that the rise in plasma glucocorticosteroid concentrations dropped from 431 to 210 per cent of the initial values in adult leghorns exposed to repeated noise stress over seven days. Adult broilers, however, did not exhibit any difference in the magnitude of rise of 11-OHKS concentrations by comparison between first and seven days of repeated stress. The initial values, however, were reached earlier by repeated noise application.

11-Hydroxycorticosteroids