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Biomedical subjects

M Frigg

Publications and source records attributed to M Frigg.

32 records · Page 2Linked to original sources
PubMed1984

Relationships between vitamin A and vitamin E in the chick.

Plasma levels of vitamins A and E were analysed during the dietary administration of two levels of vitamin A (10 000 or 50 000 IU/kg) in combination with four levels of supplemental vitamin E (0, 50, 100, or 150 mg/kg) and with or without a supplement of oil to the diet. Tocopherol levels in plasma were markedly decreased by the higher vitamin A supplementation. In contrast, the various vitamin E intakes had no influence on plasma retinol levels. The addition of oil to the diet did not affect this interaction. The absorption, distribution and elimination of labeled 3H-dl-alpha-tocopheryl acetate after an oral or intravenous administration, in combination with a high oral dose of vitamin A (100 000 IU/chick), were studied. The high oral single dose of vitamin A reduced the levels of radioactivity in all the analysed tissues and organs, when both vitamins were administered orally. However, vitamin A did not affect distribution and elimination of radioactivity, when an interaction in the gastro-intestinal tract was avoided by different routes of administration.

Animals↗
PubMed1982

Autoradiographic localisation of 3H-biotin in chick tissues.

In an autoradiographic study with a 243 days' exposure time of the autoradiographs, the tissue distribution of 3H-labelled biotin was investigated. Label being always related to cytoplasma, no label was found in the nucleus in cells suitable for such an observation. High labelling was found in differentiated cells, e.g. in hepatocytes, proximal tubular cells of kidney, villous epithelia of small intestine, fat cells, epithelial cells of proventriculus, and uropygial gland and in ependymal cells of the plexus chorioideus. Undifferentiated and rapidly proliferating tissue compartments were only weakly labelled as for example undifferentiated kidney cortex, bone marrow, lymphatic tissue. Organs engaged in fat synthesis showed intensive labelling. In these organs as well as in liver and kidney the accumulation of label is in agreement with the known biochemical function. The accumulation of label, e.g. in osteoblasts or in the ependymal cells of the plexus chorioideus, gives evidence that biotin is an essential vitamin not only for the liver and the kidney.

Animals↗
PubMed1980

Histological and cytological alterations in the skin of biotin-deficient chicks.

A basal diet with practically no natural biotin was supplemented with 10, 19, 34, 62, 111 or 200 microgram of biotin per kg. Chicks receiving these graded levels of biotin were used for histological investigations of skin samples of the foot pad and the under and upper side of the middle toe. Where there was biotin deficiency, epidermal hyperplasia, papillary growth, acanthosis and hyperkeratosis were observed on the foot pad and the under side of the toe. In the stratum spinosum, cells showed big nuclei and nucleoi, and the glycogen-containing nuclear and perinuclear vacuoles had disappeared. The alterations in the skin of the upper side of the toe were similar but far less pronounced. Cell proliferation measured by the labelling index was significantly increased in all three skin samples.

Animals↗
PubMed1979

Pyruvate carboxylase activities in red blood cells and liver of chicks and their dependency on biotin status. First results with activation assays..

Pyruvate carboxylase activities of erythrocytes and liver preparations and their in vitro stimulation by biotin were used for the determination of the biotin status of chicks. Reasonable stability of the enzyme in erythrocytes was achieved when storing the erythrocytes deep-frozen in a glycerol-containing medium. Results of the activation assays in erythrocytes and liver are compared with biotin levels in feed, plasma and liver. The pyruvate carboxylase activation assay appears to be a useful tool for assessing the biotin status of chicks.

Animals↗
PubMed1978

Stereological composition of the liver of biotin deficient and control chicks.

In an ultrastructural and stereological study the livers of 28-day-old chicks, fed either a biotin-deficient or a supplemented diet, were investigated. The biotin-deficient chicks showed the known dermal lesions and were significantly retarded in growth. About 30% less hepatocytic nuclei per unit volume liver were found in the deficient chicks than in the controls. In biotin deficiency mainly the rough endoplasmic reticulum (RER) and the mitochondria were affected. RER was diminished in volume and surface density, whereas in mitochondria only the surface densities of the outer and inner membrane were reduced. The reduction of RER is in agreement with the known reduction of protein synthesis in biotin deficiency.

Animals↗
PubMed1977

Autoradiographic and histopathologic studies on the mode of action of an aromatic retinoid (Ro 10-9359) on chemically induced epithelial tumors in Swiss mice.

The mode of action of an aromatic analogue of retinoic acid, ethyl all-trans-9-(4-methoxy-2,3,6-trimethyl-phenyl)-3,7-dimethyl-2,4,6,8-nonatetraenoate (Ro 10-9359), a compound known to possess a considerable prophylactic and therapeutic effect on skin papillomas and carcinomas, was investigated with autoradiographic and histopathologic methods. The ip application of a single dose of 1,000 mg Ro 10-9359/kg to female Swiss mice with chemically induced skin papillomas caused a 29% regression of the mean tumor diameter after 3 days and a 51% regression after 7 days. In the tumors, the number of DNA-synthesizing cells [measured by the labeling index (LI)] and the length of the cell cycle were not affected by the retinoid; thus a mode of action at the level of cell proliferation can be excluded. In the normal skin, an increase in the LI of about 30% was observed. A small effect on the cell loss was observed; however, it was not sufficient to explain quantitatively the regression of the tumors. When measured histometrically, it appeared that the loss of the horn and the formation of necroses, 3-10 times larger than in the placebo groups, were mainly responsible for the tumor regressions caused by the retinoid. After 7 days, the proportion of stroma in the tumors was increased, and dilation of the vessels and edema in the stroma proximal to the necroses were frequent.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1977

Effect of graded biotin levels in the diet on liver pyruvate carboxylase of chicks fed ad libitum and after starvation.

Decreasing levels of biotin in the diet from 200 mug/kg to 0 mug/kg reduced the pyruvate carboxylase activity per g liver and in the whole liver of chicks to 17% of the normal activity. Oral supplementation with 3 mg biotin per chick increased the enzyme activity within 24 hours back to normal. In animals well supplemented with biotin (200 mug/kg diet) 24 hours of starvation increased the per g liver pyruvate carboxylase activity. When the pyruvate carboxylase activities were related to the whole liver, no effect of starvation was found.

Animals↗
PubMed1976

Biotin deficiency in chicks fed a wheat-based diet.

A wheat-based diet produced severe biotin deficiency symptoms appearing at the age of ten to fourteen days and becoming very severe in the third and fourth week (group 1). Biotin supplementation with 50 mug/kg (group 2) reduced the symptoms almost completely, but did not restore completely growth compared to chicks receiving the diet supplemented with 300 mug biotin/kg compared to chicks receiving the diet supplemented with 300 mug biotin/kg (group 3). The plasma level of biotin was about, or lower than, 100 ng/100 ml plasma in groups 1 and 2, indicating biotin deficiency. In group 3, plasma biotin was above 200 ng/100 ml. Liver biotin, after two weeks, was low in group 1 (less than 600 ng/g), medium in group 2 (1000 to 1500 ng/g) and in group 3 above 2000 ng/g. Plasma and liver biotin levels are found to be suitable parameters for diagnosis of subclinical biotin deficiency in chicks.

Animals↗
PubMedDate not supplied

An immunohistochemical study of the distribution of biotin in tissues of pigs and chickens.

An optimised indirect peroxidase-anti-peroxidase immunohistochemical technique was used to detect endogenous biotin in frozen tissue sections from biotin-supplemented and biotin-depleted pigs and chickens. A monoclonal anti-biotin antibody was used as primary antibody in this technique. Immunoreactive biotin was detected in many tissues of both species including liver, kidney, pancreas, adipose tissue, adrenal gland, testis, brain, choroid plexus, cardiac and skeletal muscle, epithelium of the respiratory and digestive systems, skin and lymphoid tissues. The specificity of immunostaining for biotin was confirmed by the finding of reduced staining intensities in tissues of biotin-depleted animals compared to those of biotin-supplemented animals. The results of this study suggest that biotin has metabolic functions in a wider range of tissues than previously known. They also indicate that endogenous tissue biotin should be considered as a source of false-positive staining when immunohistochemical or histochemical techniques which use avidin or streptavidin reagents or anti-biotin antibodies as components of the detection system, are applied to tissue sections.

Animals↗