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Biomedical subjects

K H Kiessling

Publications and source records attributed to K H Kiessling.

At least 19 recordsLinked to original sources
PubMed1987

Changes in neck muscles in Swedish reindeer bucks during rutting season.

Three neck muscles in Swedish reindeer bucks have been studied before and during the rutting season. These were M. splenius, M. sternocephalicus and M. brachiocephalicus. For comparison, M. longissimus dorsi was chosen. Fibre composition and fibre size were studied in the four muscles as also was the metabolic potential of three enzymes, representing respiratory chain (cytochrome oxidase), beta-oxidation of fatty acids (3-hydroxyacyl-CoA dehydrogenase) and anaerobic glycolysis (lactate dehydrogenase). The extreme increase in size of certain muscles in the neck in connection with the rutting season (e.g. sternocephalicus, which increases from 250 g to 1,500 g) was to a great extent due to an increase in fibre size. In splenius, all three fibre types studied increased (I, IIA, IIB); in brachiocephalicus, mainly IIA and IIB; and in sternocephalicus, only the IIB. No corresponding fibre increase could be found in longissimus dorsi. In splenius and sternocephalicus from bucks older than 54 months, 60-70% of the fibres were of type I, and in brachiocephalicus, only about 40%. In all muscles but one, oxidative capacity (cytochrome oxidase) and beta-oxidation of fatty acids (3-hydroxyacyl-CoA dehydrogenase) decreased significantly during the rutting season. This indicates that purposes other than the enhancement of energy production by fatty acid oxidation must account for the enlargement of the neck muscles.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1987

Metabolism of zearalenone by sow intestinal mucosa in vitro.

Homogenized intestinal mucosa samples from sows were incubated with zearalenone in the presence of NADPH or UDPGA. In addition, UDPglucuronosyltransferase activity in the microsomal fraction of mucosa was determined using 1-naphthol as substrate. In the presence of NADPH, zearalenone was reduced to both alpha- and beta-zearalenol (0.37 +/- 0.18 and 0.29 +/- 0.11 nmol/mg protein/hr in the duodenum and jejunum, respectively). The beta-isomer was the predominant metabolite. Glucuronide conjugation of zearalenone was very high compared with the level of reduction occurring (11.3 +/- 6.1 and 9.4 +/- 5.8 nmol conjugated/mg protein/hr in the duodenum and jejunum, respectively). There was no correlation between the rates of glucuronide conjugation of zearalenone and 1-naphthol, indicating that they depend upon two different isoenzymes of UDPglucuronosyltransferase.

Animals↗
PubMed1985

Plasma and urinary levels of zearalenone and alpha-zearalenol in a prepubertal gilt fed zearalenone.

One prepubertal gilt, fed 192 micrograms zearalenone/kg body weight/day for 4 days, showed plasma concentrations of alpha-zearalenol 3-4 times higher than of the parent compound during the treatment. Zearalenone and alpha-zearalenol could be traced in plasma until the 5th day and in urine until the 4th day of the posttreatment period. A maximum circulating amount of zearalenone plus alpha-zearalenol, 10.4 ng/ml plasma, was found on the 4th day of treatment followed by an urinary excretion of 305 ng/ml urine. All zearalenone and alpha-zearalenol in plasma and urine were bound to glucuronic acid. On the second day of treatment the animal showed oedema and reddening of the vulva which became more pronounced during the treatment. Hormone analysis, however, showed that the animal had no oestrus cycle during the 3 week experimental period.

Animals↗
PubMed1984

Fibre composition and enzyme activities in five different muscles from the Svalbard reindeer.

beta R fibres (type I) constitute less than 10% of the semimembranosus and longissimus dorsi muscles and about twice as much of the gluteobiceps and flexor hallucis. Except for longissimus dorsi, 50% or more consist of alpha W (type IIB) fibres--in semimembranous, as much as 70%. Despite the comparatively large content of alpha W fibres, both the oxidative capacity and the capacity to metabolize fatty acids is high. Furthermore, unexpectedly small differences in oxidative capacity between the three fibre types beta R, alpha R and alpha W (I, IIA and IIB) are revealed by histochemical staining. These results indicate a tendency to bring the three fibre types closer together as regards metabolic activities, as an adaptation to the relatively tranquil life of this animal. However, the large content of alpha W fibres does not accord well with this way of life, as they guarantee quick movements. The comparatively high oxidative capacity of the alpha W fibres in the Svalbard reindeer and the fact that during starvation it is primarily alpha W fibres that contribute to the energy supply by protein degradation may nevertheless account for their abundant occurrence.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1984

Metabolism of aflatoxin, ochratoxin, zearalenone, and three trichothecenes by intact rumen fluid, rumen protozoa, and rumen bacteria.

The effect of rumen microbes on six mycotoxins (aflatoxin B1, ochratoxin A, zearalenone, T-2 toxin, diacetoxyscirpenol, and deoxynivalenol ) considered to be health risks for domestic animals was investigated. The mycotoxins were incubated with intact rumen fluid or fractions of rumen protozoa and bacteria from sheep and cattle in the presence or absence of milled feed. Rumen fluid had no effect on aflatoxin B1 and deoxynivalenol . The remaining four mycotoxins were all metabolized, and protozoa were more active than bacteria. Metabolism of ochratoxin A, zearalenone, and diacetoxyscirpenol was moderately or slightly inhibited by addition of milled feed in vitro. The capacity of rumen fluid to degrade ochratoxin A decreased after feeding, but this activity was gradually restored by the next feeding time. Ochratoxin A was cleaved to ochratoxin alpha and phenylalanine; zearalenone was reduced to alpha-zearalenol and to a lesser degree to beta-zearalenol; diacetoxyscirpenol and T-2 toxin were deacetylated to monoacetoxyscirpenol and HT-2 toxin, respectively. Feeding of 5 ppm (5 mg/kg) of ochratoxin A to sheep revealed 14 ppb (14 ng/ml) of ochratoxin A and ochratoxin alpha in rumen fluid after 1 h, but neither was detected in the blood. Whether such conversions in the rumen fluid may be considered as a first line of defense against toxic compounds present in the diet is briefly discussed.

Aflatoxin B1↗
PubMed1983

Species differences in zearalenone-reducing activity in subcellular fractions of liver from female domestic animals.

The subcellular distribution of the zearalenone-reducing activity in liver from female pig, goat, sheep, cow and hen was investigated. The distribution patterns for the reduction of zearalenone to alpha- or beta-zearalenol differed between species and was also dependent upon coenzyme. Pig and goat had the greatest ability to form both alpha- and beta-zearalenol in the microsomal fraction independently of coenzyme. Cow and hen formed alpha-zearalenol almost entirely in the microsomal fraction and beta-zearalenol only in the cytosol fraction and only with NADPH as coenzyme. The sheep was distinct from the pig and goat in having the highest alpha-zearalenol forming activity in the cytosol fraction when NADPH was used as coenzyme.

Animals↗
PubMed1982

Fibre distribution and fibre diameters in two muscles of Swedish moose (Alces alces L.).

1. Muscle samples from M. semitendinosus (S) and M. longissimus (L) were taken by autopsy, shortly after killing from 36 moose ranging approximately from 5 months to 6 yr of age. 2. The moose muscle contains three populations of fibres namely beta R, alpha R and alpha W. The muscles have a high proportion of beta R and alpha R fibres which indicates a dependence on oxidative metabolism for muscle function. 3. The moose have developed their ultimate fibre distribution at about the age of 5 months, but even after that an increase in fibre diameter for beta and alpha fibres in the (S) muscle was noted with increasing ae. This increase ceases in animals older than 1.5 yr.

Age Factors↗
PubMed1982

The effects of patulin and patulin-cysteine mixtures on DNA synthesis and the frequency of sister-chromatid exchanges in human lymphocytes.

The effects of patulin and patulin-cysteine mixtures on DNA synthesis in human blood lymphocytes were measured by assaying incorporation of [3H]thymidine into cellular DNA. Patulin inhibited and patulin-cysteine mixtures stimulated the incorporation of [3H]thymidine into DNA. The inhibitory action of patulin diminished with time in culture. Patulin was found to be unstable in the culture medium. The sister-chromatid exchange (SCE) frequency was significantly elevated by intermediate concentrations (0 . 1-0 . 2 micrograms/ml culture) of the toxin. The cells are protected from the effect at low concentrations of the toxin. There may be excessive damage at higher concentrations but only the unaffected cells go into mitosis. Therefore an increased frequency of SCEs is detected only at intermediate concentrations, or, at higher concentrations, with early harvesting. Cysteine seems to potentiate the effect of patulin on SCE frequency.

Crossing Over, Genetic↗
PubMed1982

The effect of zearalenone on growth rate, organ weight and muscle fibre composition in growing rats.

The effect of prolonged zearalenone administered to growing rats on body and organ weight as well as on muscle fibre composition has been studied. Two muscles, M. longissimus dorsi and M. vastus lateralis, were selected for fibre analyses, and the different fibre types were identified by histochemical staining. Zearalenone caused retarded growth and reduced carcass weight in both sexes. With low daily doses female growth was retarded more than male growth, with higher doses the effect was the opposite. The most evident effects of zearalenone treatment on organ weight were enlargement of the liver in both sexes and of adrenal glands and the spleen in males. No effects were found on heart, kidney, testes or uterus. No significant changes of fibre number or diameter occurred in male rats after prolonged zearalenone feeding. In female rats, however, there was a 40% decrease in the number of alpha R fibres in vastus and a corresponding increase of alpha W fibres. Simultaneously the alpha R fibre size increased with 25%. No significant changes could be found in the activity of two enzymes in vastus, cytochrome oxidase and lactate dehydrogenase, as a consequence of the zearalenone treatment.

Animals↗
PubMed1981

Partial separation and biochemical characteristics of periportal and perivenous hepatocytes from rat liver.

Suspensions of enzymatically prepared hepatocytes from starved rats were separated according to their buoyant density at 12 degrees C in linear, isosmotic gradients of metrizamide, centrofuged at low speed for a relatively short time. The recovery of cell protein was 86%. Hepatocytes of high viability formed a single band around 1.10 g/cm3 and were recovered as four density populations (P1-P4) form low to high density, respectively. The content of protein was significantly lower in population P1, while the content of neutral fat or the averaged cell size was similar in the various populations. The specific activity of alanine aminotransferase increased in the order P1-P4. The distribution of this enzyme within the intact liver acinus obtained by others indicate that a partial separation of periportal and perivenous hepatocytes had occurred. The activity patterns of lactate dehydrogenase, glutamate dehydrogenase, isocitrate dehydrogenase (NADP+) and pyruvate kinase, also with known intra acinar distributions, supported this conclusion. The hepatocytes showed signs of shrinkage after separation, but since they retained a normal ultrastructure, most enzyme activities and viability, the present technique was regarded superior to previous procedures of hepatocyte separation by density. The degree of separation was calculated from an equation (see Appendix), and the periportal/perivenous ratio for parameters measured in density populations can be obtained. The specific activity of phosphofructokinase, alcohol dehydrogenase and aldehyde dehydrogenase showed no differences between populations. However, the ratio high-Km/low-Km aldehyde dehydrogenase increased in the order P4-P1.

Alcohol Oxidoreductases↗
PubMed1981

Effect of electrical stimulation on human skeletal muscle.

The acute and adaptive effects of electrical stimulation of the quadriceps muscle were investigated in healthy male volunteers. The acute effects, i.e., depletion of phosphagen and glycogen stores and formation of lactate as well as decreases in certain enzyme activities, were similar to those found earlier for intense muscular exercise. Intermittent electrical stimulation for 4 to 5 weeks did not cause any significant changes in enzyme activities, muscle fiber characteristics, or mitochondrial properties. A 4-week period of electrical stimulation resulted in improvements of muscle strength comparable to the results of a corresponding program of voluntary training. However, the effects of electrical stimulation appeared more "position-specific" and less "speed-specific" than those of voluntary training with slow isokinetic contractions.

Adult↗
PubMed1981

Reduction of zearalenone to zearalenol in female rat liver by 3 alpha-hydroxysteroid dehydrogenase.

The distribution of the zearalenone reducing activity was investigated in liver fractions obtained by differential centrifugation of liver homogenate from adult female Sprague Dawley rats. The zearalenone reducing enzyme was identified as 3 alpha-hydroxysteroid dehydrogenase. At least two multiple forms occur of the enzyme with different subcellular locations and pH-optima. The activity was localized in the microsomes with NADH as coenzyme and in both microsomes and cytosol with NADPH.

3-Hydroxysteroid Dehydrogenases↗
PubMed1980

Time course of adaptation to low intensity training in sedentary men: dissociation of central and local effects.

The oxygen transporting capacity and the metabolic capacity of the vastus lateralis muscle were followed in parallel in 9 sedentary, overweighted men during a low intensity training program. Measurements were made at 0, 3, 6, 9, 12 and 30 weeks. Maximal oxygen uptake increased in an approximately linear fashion during the first 12 weeks (11%), but decreased a little (3%) during the following 18 weeks. Mean body weight decreased 8% (7.4 kg) during the training. The distribution of muscle fibre types, including the subgroups of type II fibres, did not change. Muscle enzyme activities remained essentially unchanged during the training. It was concluded that "central" och "local" adaptation need not occur in parallel, and that the leg oxygen utilization capacity probably does not limit the whole body's maximal oxygen uptake.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1979

Skeletal muscle metabolism, morphology and function in sedentary smokers and nonsmokers.

Smokers and nonsmokers of a homogeneous population of sedentary men have been compared with respect to skeletal muscle (vastus lateralis) morphological, metabolic and functional characteristics. The percentage type I fibres was lower and that of type IIB fibres higher in the smokers. Fibre areas were almost equal in the two groups. Muscle oxidative capacity was lowered in the smokers, as judged from decreased mitochondrial enzyme activities and a lowered fibrillar space mitochondrial volume fraction. Isometric and dynamic strengths were lower in the smokers, except at the highest velocity of movement studied. Dynamic strengths expressed in relation to isometric strength were similar at all velocities except the highest, where the smokers were relatively stronger. Muscular endurance, measured in short-term isometric and dynamic tests, was not different. It is suggested that the lowered muscle oxidative capacity and strength in the smokers may be partly a consequence of the different fibre type distribution. A possibly lower physical activity level, and tobacco smoke constituents (e.g. carbon monoxide) may also be instrumental. It is not clear whether the different fibre type distribution in the smokers is an effect of smoking per se, or if background factors are responsible.

Adult↗
PubMed1978

Metabolism of zearalenone in rat liver.

The metabolism of zearalenone in rat liver has been investigated. The studies were performed mainly with liver homogenate, though isolated microsomes and hepatocytes have also been used. Zearalenone was metabolized along two principal pathways, conjugation with glucuronic acid, which was the main route and reduction to an isomer of zearalenol. In no case, however, could all zearalenone metabolized be accounted for as conjugated zearalenone and free and conjugated zearalenol. Therefore another, so far unknown metabolite cannot be excluded. Reduction to zearalenol could be increased three times by the addition of NADH (or NADPH) and is probably catalyzed by a hydroxysteroid dehydrogenase. Some 25-50 per cent of the zearalenol could be conjugated, depending on the incubation conditions. The capacity of hepatocytes to eliminate zearalenone was estimated to be about 100 microgram per gram of liver in one hour. With a liver homogenate the highest value obtained was 82 microgram.

Animals↗
PubMed1978

Skeletal muscle metabolism and ultrastructure in relation to age in sedentary men.

In order to find out if there are age-related changes in human skeletal muscle metabolism or ultrastructure, biopsy material from 56 sedentary men aged 22-65 years was studied by means of enzyme activity determinations, histochemistry and quantitative electron microscopy. For comparison, a younger (16-18 years) and an older (66-76 years) group were included. These subjects were relatively more active. There was an increase in percentage of slow twitch fibres with age. Mitochondrial volume fraction decreased with age, primarily due to diminished mean mitochondrial volume. In spite of this, no overall decrease in the activities of five enzymes, representative of the major pathways in energy metabolism, was observed. Thus, increased amounts of enzymes per unit mitochondrial volume are implicated. Lipofuscin was more frequently found in the older groups. Correlations were present between fibre type distribution and oxidative enzymes, as well as between different enzymes. It was concluded, that the decrease in maximal oxygen uptake and muscular strength in aging humans probably may not be explained in terms of a deteriorating skeletal muscle energy metabolism.

Adolescent↗
PubMed1978

Aflatoxin in a Swedish grain sample.

So far aflatoxin has not been detected in crops grown in Sweden but only in imported feedstuffs or in feed mixtures containing imported products. During the survey for other mycotoxins in Swedish crops a compound was detected in oats which, by further analysis, was identified as aflatoxin B1. Quantitative evaluation showed concentrations as high as 2.6 ppm. The fungal population in this highly contaminated sample consisted almost entirely of Aspergillus flavus.

Aflatoxins↗