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Biomedical subjects

A Nilsson

Publications and source records attributed to A Nilsson.

At least 541 records · Page 30Linked to original sources

Influence of chain length and unsaturation on the effects of fatty acids on phosphoglyceride biosynthesis in isolated rat and pig hepatocytes.

Hepatocytes isolated from rat or pig by collagenase perfusion were incubated with [3H]glcyerol and different albumin-bount fatty acids. Among C22 fatty acids docosahexaenoic acid stimulated phosphatidylethanolamine synthesis in rat hepatocytes most effectively. Addition of docosahexaenoic acid plus either palmitic or stearic acid resulted almost in the same stimulation whereas combinations of this acid with lauric or myristic acid had no effect. Lauric acid and myristic acid alone inhibited phosphatidylethanolamine synthesis. The chain length specificity for monoenoic fatty acids was similar, the hexadecenoic and octadecenoic acids (both cis and trans) being most stimulatory. The addition of 0.2 mM ethanolamine markedly stimulated phosphatidylethanolamine synthesis, but most effects of fatty acids were similar in its presence or absence.

Adipose Tissue↗

Influence of steroid hormones on the carcinogenicity of 90Sr.

Groups of female CBA-mice were given 90Sr (14.8 kBq/g-0.4muCi/g--bodyweight) alone or in combination with polyestrodiolphosphate, methylprednisolone or nortestosterone, respectively. When 90Sr was given in the first combination, the frequency of osteosarcomas was significantly increased whereas the tumour latency time was decreased compared to mice given 90Sr alone. In combination with nortestosterone such effects were not found, whereas the combination 90Sr + methylprednisolone resulted in a strong reduction of the osteosarcoma incidence and a prolonged tumour latency time. The latter experiment was repeated in a larger experiment whereby the results were confirmed.

Animals↗

Uptake and retention of 133Ba and 140Ba-140La in mouse tissues.

The distribution of barium in the mouse has been determined qualitatively by whole-body autoradiography after i.v. administration of 133BaCl2 solution. The quantitative distribution of 104Ba and 140La has been analyzed after i.p. injections of the two nuclides in equilibrium by measuring the activity in excised organs in a two-channel scintillation counter. Approximate doses to the eyes and different parts of the skeleton have been calculated.

Animals↗

The pathology of americium 241.

Male CBA-mice were injected intraperitoneally with different doses of 241Am-citrate (16, 8, 0.4, 0.2, 0.04 muCi/kg). The two highest doses were highly destructive of the haematopoietic tissues, testes and bone tissue. The highest frequency of induced tumours of the skeleton and haematopoietic tissue was found in the 8 muCi group. In the liver, adrenal glands, kidney and heart degenerative lesions were found mainly in the higher dose groups. In the lower dose groups degenerative lesions seemed to appear earlier and at a higher frequency than in the control group.

Adrenal Glands↗

Increased cholesterol-ester formation during forced cholesterol synthesis in rat hepatocytes.

By comparing the incorporation of 3H20 and [14C]mevalonate into cholesterol in suspensions of rat hepatocytes, it was calculated that the cholesterol biosynthesis could be stimulated 4--7-fold by addition of mevalonate. The addition of 3.3--6.7 mM mevalonate also caused a 5--6-fold increase in the proportion of newly synthesized cholesterol that was esterifield. The esterification of radioactive cholesterol, entering the cells by exchange with surrounding plasma lipoproteins was also increased, indicating that a true increase in the rate of cholesterol ester formation rather than a more selective utilization of newly synthesized cholesterol for esterification, occurred. The increase in cholesterol esterification was not abolished by cycloheximide, indicating that it did not require an increased synthesis of cholesterol esterifying enzyme. Instead the data suggest that the supply of cholesterol to the esterifiable pool may be an important factor, regulating the rate of cholesterol ester formation in rat liver. The addition of 0.5 mM oleic acid to the medium did not increase the degree of cholesterol esterification significantly, whereas 2 mM oleic acid bound to 1% albumin increased the proportion of newly synthesized cholesterol that was esterified, by about 70%. The cells secreted radioactive cholesterol esters into the medium. Cycloheximide inhibited this secretion to about 80% but did not affect the rate at which newly synthesized cholesterol was transferred to surrounding plasma lipoproteins.

Animals↗

Influence of oestrogen on the excretion of strontium-90 and -85 in mice.

Groups of male CBA-mice were treated with oestrogenic hormones alone or in combination with 85Sr and 90Sr. The strontium retention was measured in special skeleton parts and also by means of whole body counting. After a period of increasing bone weight in mice treated with oestrogen and 90Sr, there were signs of a serious breakdown of that newly formed 'oestrogenic' bone tissue. The strontium retention was in no case found higher in animals treated with both the hormones and 90Sr when compared to those treated with 90Sr alone. The life span was shortened in mice given the combined treatment. The results support the theories that at the same time irradiated and stimulated cell populations are exposed to a larger risk for induction of tumours and that the irradiation injury cannot be referred entirely to the irradiation dose in a physical sense.

Animals↗

Induction of histamine release and desensitization in human leukocytes. Effect of anaphylatoxin.

Hog anaphylatoxin (AT) in concentrations from 0.5 to 5 mug/ml gives a dose-dependent histamine release from human leukocytes. Concentration of 100 mug/ml AT give the same high histamine release as 5 mug/ml. This is in contrast to the histamine release obtained with anti-IgE or allergen, which give low histamine release with high doses. The histamine release obtained with AT is completed in 20 sec and the reaction is temperature- and calcium-dependent. Treatment of cells with AT in the presence or absence of calcium makes them insensitive to another challenge with AT. Such treated cells are fully responsive, however, to challenge with anti-IgE if the pretreatment has been performed in the absence of calcium. This, together with the calcium- and temperature-dependence indicates that the AT-induced histamine release is nontoxic. Treatment of cells with AT in the presence of calcium induces, besides histamine release, decrease in sensitivity to anti-IgE, indicating that both AT and anti-IgE release histamine from the same cells. We discuss to what extent AT and cell-bound Ig share intracellular mechanisms for induction of histamine release.

Anaphylaxis↗