Biomedical subjects

M Kirchgessner

Publications and source records attributed to M Kirchgessner.

At least 19 recordsLinked to original sources

PubMed1992

Studies on the methanolysis of small amounts of purified phospholipids for gas chromatographic analysis of fatty acid methyl esters.

The methanolysis of small amounts of purified phosphoglycerides and sphingomyelin was studied and a quantitative comparison of five methods for the methanolysis of standard phosphoglycerides was made. These methods were based on methanolysis with boron trifluoride-methanol, methanolic sodium methoxide (at ambient temperature and with heating) and methanolic sulphuric acid. A further method was based on saponification with methanolic sodium hydroxide and subsequent esterification with boron trifluoride-methanol. Under the experimental conditions, only the sodium methoxide-catalysed method at ambient temperature gave complete methanolysis of phosphoglycerides. For methanolysis of sphingomyelin, boron trifluoride-methanol, methanolic sulphuric acid and methanolic hydrochloric acid were used. It was found that complete methanolysis of sphingomyelin takes 15 h at 90 degrees C. Based on these results, procedures for the methanolysis of phosphoglycerides and sphingomyelin separated by high-performance liquid chromatography are presented.

Animals↗

PubMed1992

Simultaneous determination of amounts of major phospholipid classes and their fatty acid composition in erythrocyte membranes using high-performance liquid chromatography and gas chromatography.

A method for the simultaneous determination of amounts of major phospholipid classes and their fatty acid composition in erythrocyte membranes is described. The method consists in extraction of phospholipids from erythrocyte membranes, separation of phospholipid classes by high-performance liquid chromatography, methylation of phospholipids and determination of phospholipid-bound fatty acids by capillary gas chromatography. The amounts of phospholipid classes are calculated from the total weight of phospholipid-bound fatty acids and their average molecular weights. The method was applied to erythrocytes from rats. The results show that the method is reproducible and is useful for the determination of amounts of phospholipid classes and their fatty acid composition in small blood samples.

Animals↗

PubMed1992

[Energy balance in repeated under- and overnutrition in model studies in sows].

In a model experiment eight adult sows were used to examine the effect of successive periods of under- and oversupply of energy (MUMU) on thermogenesis and efficiency of energy utilization in comparison to a constant maintenance supply (NNNN). Each treatment sequence was assigned to each animal according to a change-over design over 8 weeks. Before and after the treatment periods all the animals were fed at maintenance level (N). Energy deficiency (M) was performed by use of a basal diet with 45% of maintenance energy requirements and values for all the other nutrients sufficient for requirements. Normal (N) and excessive (U) intakes of energy was provided with supplements of starch. The total inake of gross energy during the periods MUMU was exactly the same as during NNNN. Complete energy balances were performed for each animal and period as well as during the pre- and post-experimental phase. There was no or little response of altered energy intake on carbon and energy excretion in faeces, urine and methane. However, heat production was significantly decreased by 4.1% on energy deficiency, and increased by 15.1% during energy oversupply. Summed up over the total sequence the animals produced 5.4% more heat on MUMU than during NNNN. This response was associated with a mobilization of 1.1 MJ/d tissue energy and a decrease in body weight by 2.0 kg. The efficiency of utilization of ME was 88% with energy undersupply and 75% during overnutrition. Criteria of energy balance did not differ between the pre- and post-treatment periods. It could be demonstrated that the increase in energy expenditure at oversupply was entirely explainable by the so-called obligatory thermogenesis. At the energy deficiency periods the efficiency of energy utilization reflected both energy costs of ingestion and processing of nutrients as well as a slight reduction in metabolic rate. Finally, there were no residual effects of the treatment on the energy expenditure of the animals at the end of the experiment.

Animal Feed↗

PubMed1992

[Hematological parameters, selenium concentration and glutathione peroxidase activities in serum and the liver of rats at different selenium and vitamin E levels].

The aim of the both experiments was to determine whether selenium or selenium/vitamin E supply of rats significantly influences the most important hematological criteria. With experiment 1 the influence of Se deficiency should be determined at two different times of growing. So 36 weaned rats were divided into 2 groups of 18 animals each, the half of them being decapitated at day 22, the rest on day 45. In experiment 2 with the aim to investigate a combination of deficient, adequate and excessive Se and vitamin E supply 90 weaned rats in 9 groups were decapitated at day 44. The basic diet contained 0.04 mg Se and 8 mg vitamin E per kg dry matter and was supplemented in exp. 1 with 0 mg or 0.2 mg Se and 30 mg vitamin E and in exp. 2 with 0 mg, 0.2 mg or 1.0 mg Se and 0 mg, 30 mg or 200 mg vitamin E. With Se deficiency Se concentration and GSH-Px activity in serum and liver were significantly reduced. With excessive Se supply Se concentration in serum was higher; there was no effect on GSH-Px activity. Vitamin E supply had no influence neither on Se content nor on GSH-Px activity in serum or in liver. In exp. 1 Se deficiency caused no clear changes of the analysed hematological criteria although the increase of MCV (+3%) and hematocrit (+7%) on day 22 and the increase of leucocytes (+43%) and the decrease of MCH (-3%) and MCHC (-6%) on day 45 were statistically significant. In exp. 2 these results could not be repeated. The vitamin E supply was without significant effects on the examined hematological parameters.

Animals↗

PubMed1992

Absorption, endogenous excretion, and balance of zinc in growing rats on diets with various sugars replacing starch.

The effect of partially replacing starch for various sugars on the apparent and true absorption, endogenous excretion, and balance of zinc was investigated in a study with growing rats. Six groups of five or six animals with an initial live weight of 39.4 +/- 2.7 g were fed diets that had the same Zn content (22 mg/kg), but differed in the sugar content: 1. Starch only (56%); 2. Glucose (15%); 3. Fructose (15%); 4. Sucrose (30%); 5. Galactose (15%); and 6. Lactose (30%). At the start of a 15-d fecal and urinary collection period, each animal was given an intramuscular injection of 380 kBq 65Zn for estimating endogenous Zn excretion by isotope dilution. The ratio of the specific activity of fecal Zn (after 12 d) to that of urinary Zn (after 9 d) was applied to reflect the ratio of endogenous to total fecal Zn collected from day 10 to 15. This ratio averaged 0.59, without significant differences among treatments. For this period, apparent and true absorption averaged 87.1 and 94.7% of Zn intake, respectively, and did not significantly differ among diets. Urinary excretion of 65Zn and of stable zinc by the galactose-fed rats was markedly higher than that by the other animals. Their Zn balance was, per unit weight gain, comparable with that of the other groups (30.7 vs 28.2 to 30.2 micrograms/g).

Absorption↗

PubMed1992

[Concentrations of metabolites and hormones in the blood plasma of lactating dairy cows during treatment with recombinant bovine somatotropin (BST)].

Sixteen lactating dairy cows were submitted to six injections in a four-week interval of either 640 mg prolonged release bST or of 640 mg saline (control, n = 8). The bST-treated animals were pair fed to the control cows, which were fed according to requirements. Fourteen days after each injection, blood samples were derived and analysed for metabolites and hormones. Plasma contents averaged 0.16 mmol/l non esterified fatty acids (NEFA), 2.69 mmol/l glucose, 0.43 mmol/l beta-hydroxybutyrate, 0.024 mmol/l acetoacetate, 78.8 g/l protein, 4.6 mmol/l urea, 0.81 micrograms/l insulin, 44.4 ng/l thyroxine (T4) and 1.41 ng/l triiodothyronine (T3). The bST-application was without effect on the analysed plasma contents.

3-Hydroxybutyric Acid↗

PubMed1992

[Effect of various unsaturated fatty acids on the stability of the erythrocyte membrane in the rat].

In rats restrictive feeding of a half-synthetic diet, with coconut fat as the dietary fat, caused an essential fatty acid deficiency with increased osmotic fragility of erythrocytes against hypotonic saline solutions. A 60% replacement of the coconut fat in the basal diet by pure oleic acid (18:1 n-9) or linoleic acid (18:2 n-6) by 0.6% alpha-linolenic acid (18:3 n-3), eicosatrienoic acid (20:3 n-3) or eicosapentaenoic acid (20:5 n-3) led, in the case of linoleic acid and eicosapentaenoic acid, to a significant decrease in the fragility of rat erythrocytes in comparison with the basal diet. The inefficacy of the alpha-linolenic acid treatment is possibly the consequence of a too low dietary supplementation.

8,11,14-Eicosatrienoic Acid↗

PubMed1992

Concentration of free calcium in erythrocytes and liver mitochondria of zinc-depleted rats.

The concentration of Ca(2+)-ions in mitochondria and erythrocytes of zinc-depleted rats was determined with the fluorescent Ca(2+)-indicator fura-2. The zinc-concentration of the diet did not affect the mitochondrial Ca(2+)-concentration. There was an elevation of 5% for the Ca(2+)-concentration in erythrocytes of zinc-depleted and pair-fed rats compared to ad libitum-fed animals. The cause of this elevation could be ATP-depletion because of restricted food intake.

Animals↗

PubMed1992

Dose-response relationships of alimentary PtCl2 and PtCl4 in growing rats.

In experiments with rats dose-response relationships of alimentary PtCl2 and PtCl4 were investigated. 2 x 81 animals weighing 35 g were randomly distributed among 9 treatment groups which were fed ad libitum with a synthetic diet containing various amounts of Pt during 4 weeks. Pt was added in the form of PtCl2 or PtCl4 in the amounts 0; 0.01; 0.05; 0.10; 0.50; 1.0; 5.0; 10 and 50 mg/kg diet. The Pt supplementation had no influence on life mass gain or food consumption. In the case of 50 mg/kg Pt in the form of PtCl4 the erythrocyte count and hematocrit were reduced by about 13% in comparison with the control group. Dependent on the Pt dose, the application of PtCl4 and PtCl2 induced Pt retention in nearly all tissues especially in kidney. The effects were greater with PtCl4 than with PtCl2. As a result of the higher Pt retention in the kidneys, the serum creatinine was increased for the higher doses of PtCl4.

Animals↗

PubMed1992

Excretion and distribution of injected radiozinc in rats as influenced by the type of carbohydrate.

The aim of this study was to investigate the effect of different dietary sugars on Zn status by measuring the excretion and body distribution of intramuscularly injected zinc-65 in growing rats. Thirty-two weanling rats (39.4 +/- 2.7 g) were allotted to six diets in which starch (56%) was partially substituted for glucose (15%), fructose (15%), sucrose (30%), galactose (15%) or lactose (30%). Diets uniformly supplied 22 mg/kg (dry matter) of Zn. Three days after the start of the dietary regimen each rat was injected with 40 micrograms Zn, labelled with 380 kBq 65Zn, in saline solution. Feces and urine were collected for 15 days; thereafter 65Zn distribution in the liver, pancreas, kidneys, gastrointestinal tract and residual carcass was assessed. Fecal 65Zn excretion was not significantly influenced by the diets, although the gastrointestinal tract of the galactose- and lactose-fed animals contained more 65Zn than did those fed the other diets. 65Zn in the urine and kidneys of the galactose-fed rats was markedly increased as compared with the other groups. Dietary carbohydrate source did not materially affect concentrations of stable zinc in the liver, kidneys, pancreas and residual carcass.

Animals↗

PubMed1991

[The effect of dietary fats on the hemolysis resistance of the erythrocyte membrane during alimentary zinc and calcium deficiency in rats].

In an earlier Zn-deficiency experiment (8) pair-fed-control rats surprisingly showed a 100% increased osmotic fragility of erythrocytes against hypotonic sodium chloride solutions. Because coconut fat, which is very low in essential fatty acids, was used, a deficiency of essential fatty acids was assumed. When the experiment was repeated the diet's coconut fat was replaced by sunflower oil (21% oleic acid, 69% linoleic acid). The erythrocytes of the animals with Zn-deficiency showed an increase in osmotic fragility as against the control groups fed ad libitum. The data of the pair-fed control animals was in between those two groups and did not differ from the other two groups. Using sunflower oil instead of coconut fat decreased the osmotic fragility of the pair-fed animal's erythrocytes in opposition to the preceding experiment up to 100%. Additional Ca deficiency increased the osmotic fragility of the erythrocytes significantly in all three groups. When the Zn and Ca deficiency animals were repleted over 5 days on the basic diet the osmotic fragility of the erythrocytes was decreased significantly. The results show that the use of coconut fat in a restrictive diet causes essential fatty-acid deficiency. It ist also shown that the osmotic fragility of the erythrocytes depends partially on the status of Zn in dietary fat as well.

Animals↗

PubMed1991

[Digestibility, intestinal passage time and energy value of wheat bran in model studies in sows].

An energy metabolism trial was conducted with four sows allocated to each of four levels of wheat bran (7, 14, 21 or 28 g/kg body weight 0.75.day). During 2-week experimental periods half the number of animals received increasing levels of the wheat bran supplementation, the other sows were fed in decreasing order. The basal diet was given constantly at a level of 36 g/kg Bw 0.75. Total digestibility of energy was determined by the collection method. For partioning the digestible energy into a prececal and postileal component the diet was supplemented with 0.3% Cr2O3, and samples of digesta taken by means of a cecum cannula were analyzed for this marker. The rate of passage of food was evaluated by using plastic pellets fed orally as well as inserted into the cecum. During each experimental period a complete energy balance was performed according to the methods of indirect calorimetry. The digestibility and metabolizability of wheat bran energy over the total alimentary tract was 60% and 57%, respectively. As a percentage of the total digestible energy, 70% were found in the prececal site of the digestive tract, and 30% in the hindgut fermentation. The efficiency of utilization of metabolizable energy (ME) for energy retention was 66.2%. Utilization of hindgut energy was lower by about a quarter than utilization of energy digested in the small intestine. The mean contents of ME of wheat bran amounted to 10.1 kJ/g dry matter. The ME of the wheat bran fiber (non-starch poly-saccharides) was calculated to be 5 kJ/g. The excretion of short-chain fatty acids in the feces was only 1-2% of fecal energy. The rate of passage of food decreased from 78 h (basal diet alone) to 52 h with the highest wheat bran supplementation. The prececal retention time was only 20% of the total rate of passage through the alimentary tract.

Animals↗

PubMed1991

Endogenous iron excretion. A quantitative means to control iron metabolism?

The effects of supplemental oral (0, 40, and 400 ppm) and parenteral iron (0 and 2.72 mg Fe iv given initially as a single dose) on iron absorption, excretion, and retention were determined in 30 rats. Endogenous fecal iron excretion was determined by the radioisotope dilution technique after im injection of 80 kBq Fe-59, using blood and certain body tissues as reference sources for the estimation of the specific activity (Bq Fe-59/micrograms Fe) of endogenous iron. The basal diet contained 3.6 ppm Fe. Fe(III)-hydroxide-polymaltose was used as the sole iron source in oral, iv, and im iron treatments. Iron balance as determined from day 14 to 20 of the experiment was not significantly affected by iv iron administration. Nevertheless, a temporarily reduced retention should have occurred, since differences in final body iron contents were lower than 2.72 mg, as compared to the respective untreated groups. Apparent iron absorption and iron retention increased with surplus oral iron, and the efficiency rates were highest with adequate iron supply (40 ppm). True absorption rates of iron were similar without any, and with 40 ppm Fe amounting 40 to 50% of the intake. In the iron deficient rats, half of the actually absorbed iron (about 16 micrograms/d) was lost by endogenous fecal re-excretion, and another 3 micrograms/d by the urinary route. Endogenous loss with feces and with urine increased with further oral iron supply, but at a considerably lower rate as total fecal excretion. Parenterally administered iron did not affect endogenous loss at all. The results indicate that endogenous excretion cannot be regarded as a means to eliminate excessive iron, and might actually be an inevitable loss.

Absorption↗

PubMed1991

Cellulose fermentation capacity of the hindgut and nitrogen turnover in the hindgut of sows as evaluated by oral and intracecal supply of purified cellulose.

Adult sows fed a constant amount of a basal diet received purified cellulose either orally at levels of 0 and 475 g/animal.d (Experiment 1) or intracecally at levels of 0, 285, 570 and 855 g/animal.d (Experiment 2). Each experiment consisted of subsequent periods of faeces and urine collection with the animals re-allocated to the treatments each time. With that, a total of 36 observations on each parameter was achieved. The faecal samples were analyzed for the contents of organic matter, cell wall carbohydrates and various nitrogen fractions such as bacterial N and undigested dietary N. Furthermore, N balance, urinary allantoin excretion and plasma urea concentrations were determined. In a preliminary study, the effects of freeze-drying and of shaking of the faecal samples as suspensions with water (in order to release bacteria from fibre) on content and composition of faecal nitrogen had turned out to be reproducible. Cellulose significantly enhanced faecal nitrogen loss whereas N retention was not affected due to the counteraction of urinary N loss. Plasma urea concentration reflected the situation with urinary N. The proportion of undigested dietary N and of water-soluble protein in total faecal N was somewhat increased by cellulose at cost of the bacterial N proportion which accounted for about 72% of total N on average. Urinary allantoin did not respond to the higher bacterial activity in the hindgut in the presence of supplementary cellulose. Cellulose significantly decreased the apparent N digestibility by on average about 3 percentage units per 100 g of supplementary cellulose. True N digestibility was also reduced by cellulose but did not go below 95%. The supplementary cellulose was fermented in the hindgut at similar rates of on average about 60% regardless of the route of administration. The almost 100 g of native cellulose incorporated in the basal diets were lignified by about 20%, and that is why they were fermented at a rate of only about 30%. The rate of fermentation was only slightly decreasing with increasing amounts of supplementary cellulose, and a daily quantity of 564 g (11 g/W0.75) cellulose was fermented on average if the highest level of cellulose was provided. This was within a range exclusively reported for easily-fermentable carbohydrates but was achieved in the case of cellulose only at a consistently higher level of supply. The true efficiency of bacterial protein synthesis was 5.2 g bacterial protein/100 g supplementary cellulose on average. The apparent efficiency was 60% higher averaging 8.4 g bacterial protein/100 g further apparently fermented organic matter.

Animals↗

PubMed1991

The role of experience in the development of selective zinc intake in pullets.

Selective food intake behaviour was studied in pullets that were subjected to different zinc supply in early life. During the first four weeks post-hatching three groups, totaling 72 birds, were fed either a low zinc diet (25 ppm), a complete diet (50 ppm) or both diets in a choice situation. The prior feeding experience was investigated during the subsequent ontogenetic development in two-choice dietary tests. Chicks first exhibited a preference for the high zinc diet as deficiency symptoms can be seen in depleted birds. Juvenile pullets did not prefer any diet for the duration of experimental period. Layers were initially indifferent to the supplemented zinc diet, but after reaching high laying capacity they began preferentially to select the complete diet. The results indicate that early experience with diets different in zinc content have no influence on subsequent diet preferences at choice. The ability to select is based on association learning following ingestion. A conditioned diet aversion first developed in phases of high zinc requirement as a result of negative feedback mechanisms produced by the deficient diet.

Animal Feed↗

PubMed1991

Energy metabolism of lactating dairy cows treated with prolonged-release bovine somatotropin or energy deficiency.

Two experiments were carried out with lactating Simmental x Red Holstein Friesian dairy cows. In the first experiment, 8 cows each received six injections at 4-wk intervals of either saline or 640 mg of prolonged-release bST. In the second experiment, 14 of 20 cows received 20 MJ NEL less than their daily requirement for 3 wk. Digestible and metabolizable energy were not affected by the treatments. Mobilization of body energy compensated the bST-induced increase of milk energy and supported milk production of underfed cows by two-thirds of the net energy deficit. The utilization of mobilized body energy and metabolizable energy from the diet for maintenance and milk production was unchanged. The bST and energy deficiency increased N utilization for milk production, because bST increased milk N secretion at the same N intake, and energy deficiency partly compensated the reduced N intake by N mobilization. Milk yield oscillated between the bST injections. Mean milk yield increased by 2.8 kg at constant milk composition. During energy deficit, milk yield dropped by 1.7 kg with decreasing milk protein content.

Animals↗

PubMed1991

Calmodulin activity in tissues of Zn- and Ca- deficient rats.

36 male Sprague-Dawley rats of an average body weight of 48 g were divided into 4 groups of 9 animals each. Group I was fed the basal diet with 63 mg/kg of Zn and 0.88% calcium, group II received a zinc-deficient diet (1.1 mg/kg of Zn), group III a calcium-deficient diet (0.0043%) and group IV a simultaneous zinc/calcium-deficient diet (1.1 mg/kg of Zn; 0.0043% calcium). All 4 groups received the diet in the same daily amounts, which was based on the food intake of the zinc-deficient group (II), in which food intake was reduced (as it also was in group IV) because of zinc deficiency. On day 28 all animals were killed and the calmodulin activity in the brain, muscles and testes was estimated. Calmodulin activity was determined by measuring the activation of a calmodulin-free phosphodiesterase against a calmodulin standard derived from porcine brain. Compared with the control animals zinc and simultaneous zinc/calcium deficiency reduced calmodulin activity in the muscles and testes, but not in the brain. Alimentary calcium deficiency did not influence calmodulin activity in the brain, muscles and testes.

Animals↗

PubMed1990

Activity of Na-K-ATPase and Ca-Mg-ATPase in red blood cell membranes of lead-depleted rats.

Na-K-ATPase and Ca-Mg-ATPase activity of erythrocyte membranes from lead-depleted rats were determined. In P0 generation there was no difference in activity of Na-K-ATPase and Ca-Mg-ATPase between control and depletion rats. In contrast to this, in F1 generation lead-depleted rats showed reduced activity of both enzymes. Possibly, these changes of Na-K-ATPase and Ca-Mg-ATPase activity cause the reduction of the mean corpuscular cell volume (MCV) observed in former lead depletion studies.

Animals↗