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M Boross

Publications and source records attributed to M Boross.

15 recordsLinked to original sources
PubMed1991

Effect of cigarette smoke and 2-mercaptoethanol administration on age-related alterations and immunological parameters.

In old CBA/Ca mice the effect of cigarette smoke was compared with that of 2-mercaptoethanol (2-ME) treatment. It could be stated that spontaneous death was more frequent in animals kept in cigarette smoke than in the control animals. Prevalence of hepatocellular carcinoma was higher in animals kept in cigarette smoke than in the controls. After 2-ME treatment the occurrence of hepatocellular carcinoma was significantly lower and animals without disorders were more frequent than in smokers. Body weights were lower in animals kept in cigarette smoke and differences in organ indices could be observed, too. Immunological changes were also demonstrated: in mice kept in cigarette smoke the reactivity against a foreign antigen such as sheep erythrocytes (SRBC) was lower, while after 2-ME treatment it was higher than in their controls using direct plaque formation technique. The ratio of normal reactivity (against SRBC) and autoreactivity (against mouse erythrocytes) showed a decrease in smoker animals, and an increase in the 2-ME-treated ones. The experiments showed a deleterious effect of cigarette smoke and a beneficial effect of 2-ME on age-related alterations.

Aging↗
PubMed1986

Glucocorticoids and metabolic acidosis-induced renal transports of inorganic phosphate, calcium, and NH4.

The initial rate (5 s) of Na+-dependent inorganic phosphate (Pi) uptake in brush-border membrane vesicles isolated from rat proximal tubule was decreased in metabolic acidosis, 0.42 +/- 0.02 vs. 0.59 +/- 0.05 nmol/mg protein, in vesicles from control animals. Phosphate, ammonium, and Ca2+ excretions were increased 100, 600, and 56%, respectively. These changes in brush-border Pi transport and urinary excretion of ions were largely dependent on intact adrenal glands. After adrenalectomy there were no significant changes in brush-border Pi transport, Pi, and Ca2+ excretion, whereas ammonium excretion increased only 300% compared with controls. When the glucocorticoid dexamethasone was administered to adrenalectomized animals, it mimicked the effects of metabolic acidosis both in the presence and the absence of metabolic acidosis. The initial rate of brush-border Pi transport was decreased by dexamethasone administration to 0.37 +/- 0.04 nmol/mg protein in adrenalectomized acidotic animals and 0.39 +/- 0.03 nmol/mg protein in adrenalectomized animals. Dexamethasone administered to adrenalectomized acidotic animals increased Pi, ammonium, and Ca2+ excretion 190, 690, and 23%, respectively. Dexamethasone administered to nonacidotic adrenalectomized animals increased Pi ammonium and Ca2+ excretion 165, 240, and 31%, respectively. We conclude that changes in Pi, ammonium, and Ca2+ excretion observed during metabolic acidosis were dependent on intact adrenal glands and that glucocorticoids administered to adrenalectomized acidotic or nonacidotic animals mimicked the changes observed in acidotic animals with intact adrenal glands.

Acidosis↗
PubMed1979

Influence of heavy smoking upon the bone mineral content of the radius of the aged and effect of tobacco smoke on the sensitivity to calcitonin of rats.

Using Norland-Cameron Bone Mineral Analyzer BMA 178 Type, it has been found that bone mineral content of the radius is considerably less in male heavy smokers aged 61 to 75 and 76 to 90, then in nonsmokers with similar age. Less difference was found within the group of 61 to 75 year old women. Furthermore, also it has been pointed out that the sensitivity to calcitonin of rats inhaling tobacco smoke is considerably less, than that of control rats. It is possible that smoking promotes the decrease in mineral content of bones i.e. the aggravation of osteoporosis, by the means of calcitonin resistance. The authors recommend tobacco abstinence to patients with osteoporosis and to persons who are particularly endangered by osteoporosis (e.g. in menopause, in post-gastrectomic state ect.).

Age Factors↗
PubMed1978

[Glucose absorption from the small intestine in rats of different ages (authors transl)].

Glucose absorption from the ageing rat's small intestine was studied "in vivo" using the recirculation-perfusion method of Sheff and Smyth. Different initial concentrations were used and animals of various ages (6 mo., 12 mo. and more than 27 mo. old) tested for their glucose uptake from the total small intestine (including duodenum) in the course of a twenty-minute period. Glucose was estimated by the modified o-toluidine method of Hultman. The (reciprocal) absorption data, reduced on dried intestine weight units were plotted by the Lineweaver -- Burk (regression) equations and the Km and Vmax indices derived. The results show that there is an apparent increase of the Km value in case of the old rats. Regarding the Km as an apparent affinity constant of the glucose for the carrier transport, ageing induces a considerable loss in affinity and a concomitant increase of the maximum absorptive capacity (Vmax) possible by the transfer capacity of the ageing small gut. The interpretation of the data suggest that the role of the probable age-dependent changes of diffusion-components cannot be ruled out.

Age Factors↗
PubMed1978

Influence of methyl xanthine treatment on calcitonin effect.

The presented results clearly demonstrate that theophylline, caffeine and theobromine have a blocking action on calcitonin effect as determined by the elevation of serum calcium level, although different degree of potency was found with each drugs. There is no difference in respect of the serum calcium elevation after a single dose of methyl xanthines or after a 9-10 day lasting treatment. The castration had no additional enhancing effect of the calcitonin resistance of methyl xanthine treated animals. The administration of androgens simultaneously with the methyl xanthine treatment failed to produce improvement of calcitonin sensitivty preventing the elevation of serum calcium after calcitonin injection. So the calcitonin resistance of methyl xanthine treated animals appears to be different to the calcitonin resistance of sex hormone deprived conditions because the latter could be abolished by androgen administration. Theophylline treatment resulted in a slightly but significantly elevated serum calcium comparing to controls without exogeneous calcitonin. This magnitude of elevation remains between the normocalcaemic limits.

Androgens↗
PubMed1977

Osteopenia.

Explore the source record for details and available documents.

Calcitonin↗
PubMed1977

Effect of aminoglutethimide on calcitonin sensitivity.

Studying the influence of aminoglutethimide treatment on calcitonin sensitivity, serum calcium levels were measured in normal rats, aminoglutethimide treated rats, adrenalectomized and castrated rats, following i.v. injection of porcine calcitonin. The aminoglutethimide administration caused a more distinct calcitonin resistance than surgical sex hormone deprivation. It was found that castration in most of experiments failed to enhance calcitonin resistance in aminoglutethimide treated animals. The aminoglutethimide administration may influence the steroid synthesis of adrenals, accessory adrenals and testes too. Results obtained with castrated, aminoglutethimide plus dehydroepiandrosterone treated and castrated, aminoglutethimide plus epiandrosterone treated rats affirm the earlier observations, i.e. in state of sex hormone deficiency the exogeneous androgens have an enhancing or restoring effect on calcitonin sensitivity.

Adrenal Cortex Hormones↗
PubMed1975

Postmenopausal osteoporosis: the effect of parathormone and large dose vitamin D3 on the serum calcium level in sex hormone deficient rats.

Rats deprived of adrenal and gonadel sex hormones are more sensitive than normal rats to the hypercalcaemic (osteolytic) effect of parathormone and toxic doses of vitamin D3. It is suggested that sex hormone deficiency and the consecutive decrease of calcitonin sensitivity in postmenopausal osteoporosis makes the patients unprotected against factors inducing increased bone resorption, and this leads over the years of osteoporosis.

Adrenalectomy↗
PubMedDate not supplied

Effect of smoking on different biological parameters in aging mice.

To investigate the harmful effect of smoking three groups of CBA/Ca male mice of different ages were subjected to smoking for different time durations. Body weight changes and acute cold tolerance were measured throughout the experiment. Thyroid hormone levels (T4, T3), TSH and lipid peroxidation products (as malondialdehyde and lipofuscin) were determined from either the blood or some organs. There was a decrease in body weight related to aging and it was most pronounced in the oldest animals (Group III). However, significant body-weight loss due to smoking was found in the youngest animals (Group I). Similarly, smoking resulted in a body-weight loss of the other two older groups (Groups II and III) as well. The greatest change in withstanding cold stress was measured in Group I and less so in Group II, as a consequence of smoking. Simultaneously, the youngest animals (Group I) showed the most remarkable changes in thyroxine (T4) and 3,3,4-triiodothyronine (T3) serum concentrations. Both hormone levels were significantly lower in the smokers. The T3 serum levels of the oldest animals (Group III) did not differ, while the T4 levels apparently increased. The TSH blood level in the oldest group was lower (by 20%) in the smokers compared to controls. Malondialdehyde (MDA) and lipofuscin content in most of the organs were considerably higher in the aging animals than those of the younger ones. The most significant elevations of these lipid peroxidation products were found in the smokers compared to the age-matched controls. The present results indicate that smoking probably accelerates the aging process.

Acclimatization↗