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Biomedical subjects

H Fuhrmann

Publications and source records attributed to H Fuhrmann.

At least 37 records · Page 2Linked to original sources
PubMed1998

Studies on equine lipid metabolism. 1. A fluorometric method for the measurement of lipolytic activity in isolated adipocytes of rats and horses.

A simple and sensitive method for direct and continuous monitoring of free fatty acid (FFA) release, by measuring the pH-sensitive change in relative fluorescence intensity of seminaphthofluorescein (SNAFL-1) is described. The method was designed to use a small number of adipocytes isolated from fat pads of rats and biopsy specimens of horses for the detection of decreasing pH in fat cell suspensions caused by released FFA into the incubation medium. Species specific differences of lipolysis were demonstrated when adipocytes of rats and horses are incubated with stimulators or inhibitors of lipolysis. Norepinephrine (NE) stimulated lipolysis in fat cells of rats whereas adipocytes of horses showed a measurable release of FFA when concomitantly incubated with NE and adenosine deaminase (ADA) or NE and 8-Phenyltheophylline (8-PT), respectively). The incubation of equine fat cells with NE and ADA did not influence the antilipolytic response to insulin. The method described enables micro-scaled in vitro studies on lipolytic activity.

Adipocytes↗
PubMed1997

Comparative aspects of glucose tolerance in camels, sheep, and ponies.

The aim of the study was to gain informations about factors responsible for the higher level of plasma glucose in camels as compared to sheep and ponies. An intravenous glucose tolerance test was carried out with four camels, four ponies, and four sheep by infusing 1 mmol glucose per kg body weight intravenously within 3 min. Concentrations of glucose, insulin, and non-esterified fatty acids (NEFA) were estimated in venous plasma samples taken before and within 6 hr after infusion. Basal glucose values were higher in camels (7.1 +/- 0.3 mmol/l) than in ponies (4.2 +/- 0.4 mmol/l) and sheep (3.4 +/- 0.2 mmol/l). The rate of glucose elimination was markedly lower in camels (0.270 +/- 0.018 hr-1) than in sheep (0.804 +/- 0.036 hr-1) and ponies (0.858 +/- 0.084 hr-1). The insulin response after glucose infusion was more pronounced in ponies and sheep than in camels. Concentrations of NEFA in plasma dropped 30 min after the infusion in all species, however, NEFA level decreased slower in camels than in sheep and ponies. It is concluded that the markedly higher plasma concentration of glucose in camels compared to sheep and ponies may be caused by a poorer insulin response and/or a reduced tissue sensitivity to insulin.

Animals↗
PubMed1997

[Effects of vitamins A and E on the antioxidative metabolism of weaning pigs given dietary fats of different qualities].

Early weaned piglets were divided into eight groups of 6 animals each. The animals were fed diets differing in fat quality (4% soybean oil, POZ 5 or 176) and in the content of the vitamins A (5,000 or 20,000 I.U./kg) and E (25 or 125 I.U./kg) over a period of 7 weeks. At the beginning, on day 25 and 47 blood samples were taken and analysed for vitamin A and E. In liver, heart, M. longissimus dorsi and M. semitendinosus vitamin A, E and the TBA-reactive substances were analysed. Induced lipid peroxidation was assessed by the ethane and pentane production rate in the skeletal muscle. During the weaning period a decrease in the alpha-tocopherol level was observed. In groups with the lower doses of vitamin E this effect was more pronounced. After 47 days the alpha-tocopherol concentrations in plasma and heart and skeletal muscle fell about 25-30% by offering high doses of vitamin A compared to those groups fed low doses. Oxidized fats also led to lower tocopherol concentrations in muscle tissues. Hydrocarbon production in M. longissimus dorsi and M. semitendinosus was significantly reduced in groups with the high supplement of vitamin E. A tendentially opposite effect was seen in groups supplied with high levels of vitamin A or oxidized fat. Although retinyl esters in plasma are a minor fraction of the vitamin A activity, they present 99% of the vitamin A in the liver. The distribution pattern of the different retinyl esters was independent of the amount of supplementary vitamin A. In the present experiment 20,000 U of Vitamin A reduced plasma and tissue vitamin E levels. This effect led to an increase of lipid peroxidation indicated by the higher production of hydrocarbons. The results raise concerns about further increases of vitamin A supplementation in piglet feed.

Animals↗
PubMed1996

Phospholipid fatty acids of brain and liver are modified by alpha-tocopherol and dietary fat in growing chicks.

Dietary fatty acids modify phospholipid fatty acids in brain and liver of growing chickens post-hatching. The effect of vitamin E deficiency on this process is unknown and may be relevant to the pathogenesis of chick nutritional encephalomalacia (NE). Therefore laying hens received a diet low in vitamin E (10 mg alpha-tocopherol/kg feed). Resulting chicks were assigned to nine dietary groups each fed with either oleic (18:1n-9, 58 g/kg), linoleic (18:2n-6, 57 g/kg) or linolenic (18:3n-3, 56 g/kg) acid together with 5. 25 or 125 mg alpha-tocopherol/kg feed. NE affecting the cerebellum only occurred in the group given linoleic acid and 5 mg alpha-tocopherol/kg. In 1-d-old chicks and after 1 and 2 weeks the phospholipid fatty acid composition of liver, cerebrum and cerebellum (additionally after 3 weeks) was determined. The feed fatty acids were incorporated into the liver very efficiently during the first week of life. Unsaturation of liver membranes decreased in the order dietary linolenic > linoleic > oleic acid. In liver, also, the effect of alpha-tocopherol supplementation on phospholipid fatty acids was most pronounced. The unsaturation index increased during deficiency, whereas n-9 fatty acids decreased. In the chicken brain the alterations were delayed and less distinct. The cerebellum phospholipids were rich in n-9 fatty acids and as a whole more saturated in comparison with the cerebrum. Cerebellar unsaturation increased when linolenic or linoleic acid was given. However, NE-producing dietary conditions were not accompanied by specific alterations in cerebellar phospholipid fatty acids due to the alpha-tocopherol content of the diet. Rather the alterations of membrane fatty acids in the liver seem to play a role in the pathogenesis of NE.

Animals↗
PubMed1996

[Tissue lipid peroxidation in nutritional encephalomalacia of broiler chickens].

The consequences of different dietary fats in combination with two vitamin E levels on peroxidative tissue damage of chicken brain and liver and its meaning for development of nutritional encephalomalacia (NE) were investigated. A feeding experiment was performed with 1-day-old chickens from hens on a vitamin-E-poor diet. The animals received a vitamin-E-deficient basic diet containing 10% fat, rich in either C18:3n3-, C18:2n6- or C18:1n9-fatty acids. The fat was given either fresh or oxidized (peroxidation number: 250) and 0 or 50 ppm alpha-tocopherylacetate was added. Typical symptoms of NE occurred mainly in those groups fed with n6-fatty acids beginning on day 7. In order to evaluate oxidative tissue damage, conjugated dienes, fluorescent pigments and TBA-reactive substances were determined in liver, cerebrum and cerebellum. Brain was examined histologically. In liver and cerebrum, the feeding of oxidized fats led to a 20% increase in conjugated dienes. Fluorescent pigments could be determined only in the brain tissues. However, feeding conditions had no effect, although autofluorescence was observed histologically in the affected animals. TBA-reactive substances were heightened in cerebrum (30%) and liver (130%) as a result of feeding linolenic acid. Vitamin E deficiency doubled TBA-reactive substances only in the liver. The parameters measured did not show intensified lipid peroxidation in the cerebellum of the animals fed the NE producing diet. Rather, the liver seems to be affected by the oxidative stress.

Animals↗
PubMed1996

[The effect of vitamin A and beta-carotene on the vitamin E status, ejaculation parameters and health of boar used for insemination].

In this study consequences of vitamin A-supplementation to the vitamin E-status was investigated in the boar. Three groups of boars, each with 9 animals were fed over a period of seven month with 30000 I.E. Vit. A/kg concentrate (group A), 90 mg b-carotene + 1000 I.E. Vit. A/kg (group B) and 1000 I.E. Vit. A/kg (group C). Every boar was given 100 mg Vit. E/kg plus 50 ml soybean oil/kg to induce oxidative stress. After four month group C showed a higher amount of tocopherol in serum (p < 0.05). The amount of tocopherol in serum of the group B were exactly between group A and C. The amount of retinol in serum of the group C began to decrease after three month due to the high reserve capacity of the liver (p < 0.01). The retinyl ester in serum reflected the state of supply. 90 mg b-carotene led to an efficiency of 15000 I.E. Vit. A. The vitamin antagonism between Vit. A and Vit. E is not based on an antagonism of the intestinal resorption. There was no influence on the daily sperm production caused by different supplementations. The sperm quality was lowered in group C; the number of defective sperm increased (p < 0.001). The supplementation of soybean oil lead to an increase of the saturated fatty acids in the fatty acid pattern of the sperm cells. The increase of saturated fatty acids was the lowest in group C that showed the highest amount of tocopherol in serum.

Animal Feed↗
PubMed1995

Alpha-tocopherol and phospholipase A2 in liver and brain of chicks posthatching: the influence of dietary fat and vitamin E.

One of the classical vitamin E deficiency syndromes is nutritional encephalomalacia in broiler chicken. Subject of this study was the influence of dietary fatty acids and vitamin E on phospholipase A2 and alpha-tocopherol concentration in liver, cerebrum and affected cerebellum posthatching. Therefore, chicks were fed either oleic, linoleic or linolenic acid rich fats together with 5, 25, or 125 ppm vitamin E. At the end of 0, 1, 2 and 3 weeks the tocopherol content and phospholipase A2 activity of liver, cerebrum and cerebellum were determined. Dietary fatty acids did not influence tissue alpha-tocopherol and phospholipase A2. In the vitamin E-deficient cerebellum the enzyme activity of cytosolic phospholipase A2 was increased. Due to its low content of vitamin E the cerebellum is the most susceptible tissue to oxidative stress during vitamin E deficiency.

Aging↗
PubMed1995

The influence of dietary fatty acids and vitamin E on plasma prostanoids and liver microsomal alkane production in broiler chickens with regard to nutritional encephalomalacia.

Nutritional encephalomalacia (NE) in broiler chicken is considered as a peroxidative dysfunction caused by vitamin E-deficient diets. A feeding experiment was performed to investigate the consequences of feeding different fats in combination with increasing amounts of vitamin E on liver lipid peroxidation and plasma prostanoid pattern. Newly hatched chicks from hens on a vitamin E-poor diet were fed with either mainly linolenic, linoleic or oleic acid-rich oils in a vitamin E-deficient (5 ppm) basic diet. The animals were supplemented with vitamin E on three levels (0, 20 or 120 ppm). On appearance of the first symptoms of NE after 8 days post-hatching, the animals were examined. Typical symptoms with a high incidence only occurred in the group fed linoleic acid and 5 ppm vitamin E. Plasma prostanoids and microsomal alkane production in liver as a measure of endogenous lipid peroxidation were determined. The dietary conditions affected plasma prostaglandin E2 and thromboxane A2, but not prostacyclin. However, it seems unlikely that the prostanoids are involved in the pathogenesis of NE. Liver lipid peroxidation increased in vitamin E deficiency. The level of alkanes depended on the type of fat supplied. The consequences of the different dietary fats in combination with vitamin E deficiency on peroxidative metabolism of broiler chickens are evident, indicating that a high level of oxidative stress is imposed by the linoleic acid-rich fat.

Alkanes↗
PubMed1994

Bioefficiency of different tocopherols in chicken as assessed by haemolysis test and microsomal pentane production.

Bioefficiencies of alpha-, gamma- and delta-tocopherol in comparison with all-rac-alpha-tocopherol were established in broiler chickens. For this, 1-d-old male broiler chickens received a diet deficient in vitamin E and supplemented with increasing doses of the corresponding tocopheryl acetates. After 2 and 3 weeks of feeding, the animals were killed to obtain blood and liver samples. The ex vivo tests used were detergent-induced haemolysis and pentane production by liver microsomes. Bioefficiencies were calculated by comparison of the dose-response curves. It is concluded that haemolysis and pentane production are appropriate indicators of the bioefficiency of tocopherols in broiler chickens. The values obtained by both tests hardly differed and agree well with the figures previously obtained from rats and other species.

Animals↗
PubMed1994

The influence of dietary fat on hepatic bioactivation of aflatoxin B1 in rats.

Fischer 344 rats were fed a low-fat high carbohydrate (HC) diet, an isocaloric fat-containing (IC) diet, a hypercaloric fat-containing (HF) diet or a commercial rodent chow. The effects of these diets were studied on the binding of aflatoxin B (AFB1) to exogenous DNA, and on the activities of hepatic glutathione transferases (GSTs), cytochromes 2B1 and 1A1. Microsome-mediated binding of [3H]AFB1 to exogenous DNA was significantly lower in the HC-rats than in the chow and IC-fed rats. No significant differences were noted between HF and either HC or IC rats. There was no significant difference in hepatic GST activity of rats fed the different diets. Our results suggest that high-carbohydrate low-fat diets reduce microsome mediated epoxidation of AFB1 to a larger extent than high-fat diets. In general, high fat diets increased cytochrome 1A1 and 2B1 activities relative to chow and high carbohydrate diet. This suggests greater detoxification of AFB1, thus reducing the amount of AFB1 available for hepatic macromolecular binding.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1994

[The contributions of the hormones insulin, cortisol, somatotropin and total estrogen to the pathogenesis of sheep ketosis].

The concentrations of hormones, metabolites and electrolytes in plasma of 45 ewes have been examined repeatedly during gestation (day 80 to 149) and at the third day of lactation. Healthy single pregnant (n = 8) and twin pregnant ewes (n = 12) have been compared with ewes sick with subclinical (3-hydroxybutyrate > 1,0 mmol/l, n = 6) and clinical (3-hydroxybutyrate > 1,6 mmol/l, n = 19) pregnancy ketosis. The concentration of 3-hydroxybutyrate, glucose, calcium, sodium and growth hormone in the plasma of the healthy animals were higher post partum than ante partum, while the concentrations of inorganic phosphorus, cortisol and total oestrogen were lower post partum than during pregnancy. In the pregnant ewes the concentrations of 3-hydroxybutyrate, bilirubin, total oestrogen and growth hormone in the plasma increased, while the concentration of insulin decreased with raising number of fetuses. In comparison with the healthy twin pregnant ewes the animals with subclinical and clinical pregnancy ketosis showed increased values of bilirubin, glutamate-dehydrogenase, growth hormone, total oestrogen, cortisol and cortisol/insulin ratios as well as decreased values of glucose, insulin and potassium. Individual differences of the animals within their groups were observed for the examined hormones as well as for glucose, calcium, sodium and potassium (analysis of variance). Beside multiple pregnancy low insulin values and high cortisol/insulin ratios, which are obviously due to individual disposition, influence enhanced ketogenesis and disorder of glucostasis.

Animals↗
PubMed1994

[The effect of treatment with vitamin E or selenium on the course of salinomycin poisoning in swine].

Experimentally induced salinomycin toxicosis in weanling pigs showed typical clinical signs of an intoxication with a polyether antibiotic. Severe ataxia and recumbency were the most prominent symptoms, which could be attributed to acute skeletal muscle necrosis by estimation of muscle enzyme activities (creatine kinase, aspartate aminotransferase) and histopathological examination. Intoxication had neither influence on concentrations of vitamin E and selenium-dependent glutathione peroxidase in plasma and different organs nor on contents of fatty acids in skeletal muscles. No signs of increased lipid peroxidation in muscle tissue could be found. Prophylactic application of vitamin E or selenium one day before administration of salinomycin as well as treatment on the following days produced no protective effects. The treated pigs showed equal clinical and pathomorphological alterations as the untreated animals, although applications caused a significant increase of alpha-tocopherol and glutathione peroxidase concentrations in blood and different organs.

Animals↗
PubMed1993

The effect of diet on aflatoxin B1 binding to hepatic macromolecules in rats.

Fischer 344 rats were fed a low-fat high carbohydrate diet (HC), an isocaloric fat-containing diet (IC), a hypercaloric fat-containing diet (HF) or rat chow. Covalent binding of AFB1 to liver DNA, RNA and total proteins was investigated in a 24 hour period following administration of a single intraperitoneal dose of AFB1 (1 mg/kg body weight). AFB1 binding to nucleic acids was greatest in the HC and was generally significantly lower (p < 0.05) in the HF, IC and rats fed chow. The results suggest that fat decreases hepatic macromolecular adduct formation by inhibiting activation of AFB1 to the epoxide or by enhancing the activity of detoxification pathways.

Aflatoxin B1↗
PubMed1993

[Nutrition disorders in fattening pigs in an "organic" facility].

In a herd of fattening pigs under an organic system of management, the following problems were observed: sudden deaths, skin diseases, diarrhea, increased restlessness and cannibalism. The diet consisted of cereals (barley, wheat, rye), field beans, lime stone and deteriorated, raw potatoes without addition of a mineral mixture. Deficiencies of sodium, zinc and selenium were found in the diet and in the animals (blood samples, autopsy). The vitamin E status in the pigs was also below normal.

Animal Feed↗
PubMed1992

[Intravenous infusion of volatile fatty acids as a metabolic loading test for the evaluation of the possible effects of butafosfane on the energy metabolism of cattle].

In 10 German Black and White heifers metabolic stress reactions were induced by intravenous infusion of propionate and butyrate to demonstrate possible effects of prior medication with butafosfane. This investigation included a preliminary feeding period, followed by 18 hours of feed withdrawal, premedication with butafosfane or placebo and infusion of volatile fatty acids. Reactions were assessed by monitoring biochemical and clinical parameters. A total of 19 blood samples per series were taken in which the concentrations of glucose, free fatty acids, volatile fatty acids, beta-hydroxybutyrate, cortisol and insulin were measured. Clinical parameters recorded included heart rate and respiratory rate. During loading with propionate effects of butafosfane on plasma levels of cortisol and insulin could be demonstrated. The differences noted in the other parameters were only insignificant. The loading test chosen is suitable for the demonstration of effects of butafosfane on metabolic parameters which could hardly be influenced by this substance in unstressed animals.

Animals↗
PubMed1991

Glucose entry rate in dairy cattle as determined by stable isotope 13C-labelled glucose at different stages of reproduction.

1. Uniformly labelled stable 13C-glucose was used to study glucose entry in high yielding Holstein cows (n = 8) under normal production conditions. 2. The single injection technique was repeated at three different reproductive phases. A two compartment model was applied to calculate mean entry rates of glucose resulting in: (1) Terminal phase of pregnancy (2 weeks a.p.): 0.41 g/hr/kg0.75; (2) Peak lactation (6 weeks p.p.): 0.97 g/hr/kg0.75; (3) End of lactation (37 weeks p.p.): 0.61 g/hr/kg0.75. 3. Data from studies using radioactively labelled tracers are in good agreement with our results obtained without any restrictions implied by the handling with radioactive substances.

Animals↗
PubMed1990

Production and use of bovine DNA libraries: DNA-sequencing.

An important part in the use of genomic DNA libraries is the sequencing of identified clones for detailed information. In this study, methods for DNA sequence analysis were elaborated and employed for the k-casein gene, a bovine milk protein. The results encourage further research.

Animals↗