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Biomedical subjects

M Harri

Publications and source records attributed to M Harri.

At least 37 records · Page 2Linked to original sources
PubMed1988

Effect of the cold environment on organophosphate toxicity and inhibition of cholinesterase activity.

1. Rats were used for studies on organophosphate (OP) toxicity both in acute and chronic cold exposure. Furthermore the effects of OPs on tissue acetyl- and butyrylcholinesterase activities were studied in the cold environment. 2. No change in the toxicity of dichlorovinyl phosphate (DDVP) was observed whereas that of diisopropylphosphofluoridate (DFP) increased 1.5-fold at +5 degrees C. 3. Chronic exposure to cold produced no change in DFP toxicity. 4. The survival time in acute cold exposure (1.1 x LD50 DFP) was longer than in chronic exposure or at +20 degrees C. 5. In control rats, chronic cold exposure increased blood BuChE and decreased BuChE in lungs. 6. A dose-dependent inhibition of cholinesterases was observed. 7. AcChE in the liver of chronically cold exposed rats was more sensitive to DFP inhibition compared to acute exposure. 8. Blood AcChE activity correlated only to AcChE in brain and lungs in rats.

Acetylcholinesterase↗
PubMed1988

Physical exercise affects cholinesterases and organophosphate response.

1. Cholinesterase activities in blood and tissues of control and exercising rats with and without organophosphate (OP) exposure were studied. 2. Physical exercise increased total cholinesterase and butyrylcholinesterase activities in rats without OP exposure in blood and diaphragm. In brain physical exercise had no effect on acetylcholinesterase activity. 3. Physical exercise diminished cholinesterase inhibition in blood and tissues after OP exposure.

Acetylcholinesterase↗
PubMed1986

Effects of 100-Hz magnetic fields with various waveforms on the development of chick embryos.

Chick embryos were exposed during their 52 first hours of development to 100-Hz magnetic fields. Sinusoidal, square and pulsed waveforms were used at average field strengths from 0.1 A/m to 80 A/m. After exposure, the embryos were examined for abnormalities and classified by the developmental stages. When bipolar oscillations (oscillating at both sides of the zero-level) were used, the percentage of abnormal embryos was significantly increased above 1 A/m. In exposure to unipolar square waves, no significant effect on the percentage of abnormalities could be demonstrated. The developmental stage was possibly affected by unipolar square waves at 0.1 A/m, all other field strengths and waveforms being apparently ineffective.

Animals↗
PubMed1986

Seasonal changes in energy economy of farmed polecat as evaluated by body weight, food intake and behavioural strategy.

An analysis of seasonal changes in energy budget of the farmed polecat (Mustela putorius) was performed in subarctic climate. Cyclical variations were found in the body weight of male polecats from maximum values in February (2.1 kg) to minimum values in June-July (1.5 kg). There were only minor seasonal changes in the body weight of females. There was a direct relationship between body weight and voluntary energy intake on one hand (r = 0.89) and an inverse relationship between body weight and locomotor activity (r = -0.88) on the other hand. Energy intake was significantly (p less than 0.05) higher during winter (224 kcal/animal/day) than during summer (142 kcal/animal/day). Total time spent outside the nest was at its maximum during the winter months (60 min/day). The results suggest that in male polecats, changes in absolute food intake induce seasonal changes in body weight. Seasonal changes in locomotor activity seem to be less important in energy balance regulation. The fact that the body weight of females showed only minor seasonal variation supports the role of sexual hormones in the control of the body weight.

Animals↗
PubMed1986

Ammonia levels in the whelping nests of farmed raccoon dogs and polecats.

Ammonia concentrations were measured in the nests of farmed raccoon dogs (Nyctereutes-procyonoides Gray, 1834) and polecats (Mustela putorius) at weaning time. Ammonia levels in the nests of raccoon dogs and polecats varied from 1 to 43 ppm and from 0 to 5 ppm, respectively. In the raccoon dog, with increasing litter size, the ammonia concentrations tended to increase exponentially. In the polecat, no marked relationship between litter size and ammonia levels were found. The results show that no special adaptations are required in farm life because even the highest ammonia concentrations measured were below the harmful level.

Ammonia↗
PubMed1986

Heat loss of farmed raccoon dogs and blue foxes as evaluated by infrared thermography and body cooling.

Infrared thermographs showed that heat loss of the raccoon dog (Nyctereutes procyonoides Gray 1834) is greatest from the chest, the head, the abdomen and the feet. The blue fox (Alopex lagopus) seems to be somewhat better insulated. Mass-0.75 specific heat transfer coefficients (W/kg 0.75 per degrees C) in both species were similar. The wooden nest was able to decrease it significantly. The results support the conclusion that heat loss, and thus the energy costs, of studied species could be reduced by providing them with either a winter nest or a rest-shelf in the cage.

Animals↗
PubMed1986

Is swimming exercise or cold exposure for rats?

Rats were trained by daily swimming sessions (up to 3 h per day) for at least 6 weeks in water at 30, 36 and 38 degrees C. After this training, the adaptive changes obtained were compared with those typical of cold-acclimated (cold-specific changes) and running-trained (training-specific changes) rats. The most typical training-specific change, an increased activity of oxidative muscle enzymes was negligible for swimming-trained rats, while the lowered activity of muscle lactate dehydrogenase was evident for all trained groups. Cold-specific changes, such as increased food intake, increased calorigenic response to injected noradrenaline, an increase both in mass and metabolic capacity of brown adipose tissue, and maintenance of the stores of ascorbic acid and muscle glycogen during cold exposure, were observed for rats trained at 36 and 30 degrees C. The cold tolerance test in cold air did not make any distinct difference between the rats trained at different water temperatures, while in cool water the 30 degrees C -swimmers were clearly superior to other groups, that is, their cooling rate was slowest. Other adaptive changes were found, to a variable extent, for all trained groups. These included loss of body fat, cardiac hypertrophy, reduced urinary catecholamine excretion after test swimmings either in cold or warm water, increased tail-skin temperature response to isoprenaline, and a higher tail-skin temperature in response to cold. Generally, however, the adaptive changes observed for 30- and 36 degrees C-swimmers were similar, while the changes observed for 38 degrees C-swimmers were different. The latter group neither displayed any cardiac enlargement nor any cold-specific changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1986

Effects of social competition for feed on growth of farmed raccoon dogs.

To test whether or not social competition influences food consumption and growth in farmed raccoon dogs (Nyctereutes procyonoides, Gray 1834), animals were placed singly, in pairs and by threes in standard cages and fed ad libitum or restricted feed portions. Daily feed intake of single, ad libitum freely fed animals, 930 +/- 150 g, was significantly more than that of animals caged in pairs (750 +/- 45 g) or by threes (730 +/- 210 g). Animals on restricted feeding consumed all the feed supplied, i.e. 550 g per animal daily. Higher feed intake was associated with a poorer apparent digestibility of protein, fat, carbohydrates and energy during the period of maximal growth rate in August. Approximately the same final body weights were achieved despite of the number of animals per cage. Animals on ad libitum feeding tended to be heavier than those of restricted feeding. However, the interindividual variation in body size was large even in single animals fed ad libitum. No significant interactions between social status and feed availability were found, i.e. the shortage of feed affected equally all social classes. No marked differences in foot length or skin quality between experimental groups were found.

Animals↗
PubMed1985

Uptake and distribution of radioiodine, and the effect of ambient nitrate, in some fish species.

125I uptake by the thyroid was most pronounced in the smelt (Osmerus eperlanus), perch (Perca fluviatilis), rainbow trout (Salmo gairdneri), roach (Rutilus rutilus) and bleak (Alburnus alburnus). Unlike other tissues, only the muscle in the species studied no relative accumulation of 125I as compared to the ambient water. The Crusian carp (Cyprinus carassius) indicated the lowest levels of accumulation of 125I among the species tested. Thyroid radioiodine concentration was independent of the length of the fish in the rainbow trout and perch. In the rainbow trout, however, the liver and muscle radioiodine concentrations decreased significantly with increasing length of the fish. Exposure of rainbow trout to water containing supranormal concentration of nitrate (1500 micrograms/l) resulted in lowered 125I uptake. The same phenomenon was observed for the perch and Crusian carp, with low nitrate concentrations, while with higher nitrate concentrations, the uptake levels were again increased. Thyroid function, as judged from the conversion ratio and T/S ratio, was not affected by nitrate.

Animals↗
PubMed1985

Response to cold in the blue fox and raccoon dog as evaluated by metabolism, heart rate and muscular shivering: a re-evaluation.

Oxygen consumption (ml kg-0.75/min) in relation to ambient air temperature at or below the lower critical temperature (Tlc) of the winter-furred raccoon dog (+10 degrees C) and the blue fox (-6 degrees C) is described by the equations y = 14.8-0.28x and y = 7.5-0.20x, respectively. Muscular shivering activity (integrated EMG) of both species increased below thermoneutrality parallel with increasing oxygen uptake and heart rate. Seasonal changes in measured metabolic parameters were evident for both species. The results suggest that the overall body insulation or the metabolic response to cold are not essentially worse in the raccoon dog as compared with the blue fox. It is concluded that earlier speculations of surprisingly wide thermoneutral zone and very low Tlc of the Arctic fox are not evident for the blue fox.

Animals↗
PubMed1985

Effect of dietary protein concentration and ambient temperature on the energy, protein and water metabolism of the rat.

Groups of rats (n 8) were offered, to appetite, diets containing 10 (LP), 25 (MP) and 45 (HP)% of gross energy as protein energy from 45 d of age to slaughter 50 d later. At 53 d of age, half the rats on each diet were left at 22 degrees while the other half were transferred to 6 degrees. Water balances were measured daily, and digestibilities of energy and nitrogen and the metabolizability of the diets were measured for each rat over a 7 d period at some stage between the age of 74 and 95 d. The rats were slaughtered at day 95 and their carcasses were analysed for protein, lipid, energy and ash contents. Energy expenditure was calculated as the difference between metabolizable energy intake and energy retained. Growth performance was best on the MP diet at both temperatures. At 22 degrees the rate of gain of body-weight and of energy retention, although not of protein, were slightly reduced on the HP diet while overall performance was markedly inferior on the LP diet. At 6 degrees the LP diet, while not so good as the MP diet, led to significantly better all-round growth performance than did the HP diet. Cold increased the energy expenditure of the rats by 50% (109-138 kJ/d); the increase was greater for the LP group than for the HP group. Intrascapular brown adipose tissue hypertrophied in response to cold and to the LP diet. Adrenal gland size was significantly increased by cold exposure and by increasing level of dietary protein concentration. Urine volume was more closely related to the intake of protein than to that of energy. Urinary N concentration for the HP rats was approximately double that for those on the LP diet. Cold-exposed rats had a high water content in their fat-free carcasses, but there were no differences between the dietary treatments.

Adipose Tissue, Brown↗
PubMed1985

Growth and fur parameter variations of farmed raccoon dogs.

Growth, body composition and hair coat parameter variations were evaluated in farmed raccoon dogs (Nyctereutes procyonoides) reared in a conventional two animals -in-cage-system. Daily rate of body weight gain (BWG) of litters very significantly (p less than 0.001) correlated with their time of birth (r = 0.879); the later in spring they were born the faster they gained weight. Final body weight (FBW) of the whelps was to be predicted from their body weight (BW) in early August (r = 0.689). There was no significant correlation between litter size and FBW, BWG or daily rate of BWG. Social competition for food produced great variation in FBW of the animals; the difference between the heavier and lighter raccoon dogs within a cage averaged 1.2 kg (p less than 0.001). Except in FBW and obesity index, there was no significant differences in other parameters between these social groups. Social status within a cage explained only 3.6% of the pelt quality variation while it could explain 52% of the BW variation. Litter explained 36% of the pelt quality, whereas it could explain 4.9% of the BW variation only. Social status and litter did not show any significant two-way interactions. Pelt weight very significantly (p less than 0.001) correlated with pelt quality (r = 0.48) and mass (r = 0.55). Also mass very positively (p less than 0.001) correlated with pelt quality (r = 0.82), indicating that the subjectively estimated pelt quality, in fact, can be derived directly from its weight. We conclude that differences in growth parameters and fur characteristics are mainly produced by social and hereditary factors, respectively.

Animal Feed↗
PubMed1984

Seasonal changes in thermoregulation of the raccoon dog (Nyctereutes procyonoides Gray 1834).

Oxygen consumption (ml X kg-0.75/min) in relation to ambient temperature (Ta) in the raccoon dog whelps at the ages of 7-9 weeks and 17-19 weeks is described by equations y = 32.9-0.69x and y = 26.2-0.49x, respectively. The corresponding equations to adults in summer and winter pelages are y = 19.6-0.46x and y = 14.5-0.32x, respectively. The cooling constant (min-1) of deceased raccoon dogs decreased exponentially with increasing body mass, while M-0.75 specific heat transfer coefficient (W X kg-0.75/degrees C) regressed linearly on body mass, y = 0.124-0.00066x. Cooling rate of deceased animals were more dependent on body mass than on pelage quality.

Animals↗
PubMed1984

Related and unrelated changes in response to exercise and cold in rats: a reevaluation.

Groups of rats were subjected to various treatments: continuous exposure to cold (5 degrees C); exercise by running; intermittent cold exposure, -20 degrees C daily for 60 min; and in some experiments combined influence of cold acclimation and exercise for at least 6 wk. The resulting adaptive changes can be grouped in three different categories. Cold-specific changes included increased food intake, an increase in both mass and metabolic activity of brown adipose tissue leading to an increased capacity for nonshivering thermogenesis, and maintenance of the stores of ascorbic acid and muscle glycogen during cold exposure. These changes were associated with an improved resistance to cold with which the rats were able to maintain their body temperature in both cold air and water were typical of rats previously exposed to cold. Training-specific changes typically included increased activities of aerobic muscle enzymes and decreased activity of lactate dehydrogenase and a higher O2 uptake and shivering activity during cold exposure as compared with sedentary control rats. These changes were observed for trained rats only and were not associated with an improved resistance to cold. Other adaptive changes were found, to a variable extent, for all treated rat groups. These included cardiac hypertrophy, reduced urinary catecholamine excretion during and after stress situations, increased tail skin temperature response to isoproterenol, and a higher tail skin temperature during exposure to cold. There were no systematic differences between groups in changes of blood glucose, glycerol, or lactate concentrations during cold exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1983

Thermoregulation of polecat and raccoon dog: a comparative study with stoat, mink and blue fox.

1. Oxygen consumption (ml X kg0.75 per min) in relation to ambient temperature (Ta) in the raccoon dog (Nyctereutes procyonoides), polecat (Mustela putorius), mink (Mustela vison) and stoat (Mustela erminea) is described by equations y = 14.2 - 0.23x, y = 26.3 - 0.47x, y = 26.9 - 0.33x and y = 39.0 - 1.06x, respectively. Resting metabolic rate (RMR) of blue fox (Alopex lagopus) could be measured only at thermoneutrality. 2. In polecats, calorigenic response to noradrenaline was about 40% above the RMR, while in raccoon dogs it was absent. 3. The cooling constant (per min) of deceased raccoon dogs was similar to that measured for blue fox (0.0008), but considerably higher than that measured for dog (beagle 0.0016) or polecats (0.0023-0.0031).

Animals↗
PubMed1983

Hepatic biotransformation in farmed blue fox and raccoon dog.

In farmed raccoon dogs and blue foxes, the hepatic content of cytochrome P-450 and the activity of polysubstrate mono-oxygenase with benzo(a)pyrene and 7-ethoxycoumarin as substrates, as well as activity of UDP glucuronosyltransferase were of the same order of magnitude as those in the laboratory rat. The amount of reduced glutathione tended to be higher in canids. There existed differences in the biotransformation activities between raccoon dogs from different farms. These cannot, however, be systematically related to the quality of food, body composition and succinate dehydrogenase activity.

Animals↗
PubMed1983

Health problems in a newly established fur farming area in Eastern Finland.

Health problems of newly established fur farms were defined in Kuopio Province. Three methods of data collection were used: 1) interviews with local farmers 2) authors' personal observations and 3) determination of endoparasitic infestation. Sanitation on farms were found to be rather good. The most commonly occurring diseases were urinary tract inflammations, intestinal infections and ectoparasites. However, health conditions were found to be satisfactory and most problems were of economic nature.

Animal Husbandry↗