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Biomedical subjects

O Koldovsky

Publications and source records attributed to O Koldovsky.

At least 55 records · Page 3Linked to original sources
PubMed1979

Relationship of thyroid status and serum N-acetyl-beta-glucosaminidase isoenzyme activities in humans.

Serum from 28 hyperthyroid, hypothyroid, and euthyroid pre- or early puberty females was examined for N-acetyl-beta-glucosaminidase (HEX) activity. Total, isoenzyme A (labile), and isoenzyme B (stable) levels were determined for this enzyme. A high degree of correlation (r = 0.76; p less than 0.001) exists between total hexosaminidase activity and thyroid hormone levels (as reflected by the Free Thyroxine Index). Examining each isoenzyme individually, A is selectively enhanced (r = 0.84; p less than 0.0005) whereas B displays no significant change regardless of thyroid activity. In hyperthyroid individuals, levels of total hexosaminidase (730 +/- 67 units) (mean +/- S.D.) and isoenzyme A (516 +/- 46) were significantly higher than levels found in either the hypothyroid (total: 547 +/- 30; isoenzyme A: 352 +/- 31) or euthyroid (total: 620 +/- 81; isoenzyme A: 423 +/- 45) groups. However, no change was observed in levels of isoenzyme B among hypothyroid (195 +/- 19), euthyroid (197 +/- 43) and hyperthyroid (215 +/- 32) groups. These data substantiate our earlier findings in the rat, wherein thyroxine administration evoked a similar response in the liver. They are of particular interest in light of the deficiency of HEX A in variants of GM2 gangliosidosis.

Acetylglucosaminidase↗
PubMed1979

Development of fatty acid esterification mechanisms in rat small intestine.

Fatty acid esterification was measured in fetal jejunal and ileal isografts implanted under the kidney capsules of adult host rats and compared to the age-controlled intestine grown in situ. Studies were conducted on the 21st, 35th, 49th, and 63rd postconceptional days, corresponding to prenatal, suckling, weaning, and weaned rats. Substantial fatty acid esterification activity was found in prenatal jejunum but not in ileum. A proximal-distal gradient of fatty acid esterification was observed in all groups grown in situ, but not in isografts. The monoglyceride pathway (MG-P) accounted for about one-third of total fatty acid esterification (TFAE) in jejunum grown in situ and remained constant through the study. In the ileum, MG-P was the major esterification pathway during the first 4 postnatal weeks, but decreased progressively after weaning to become insignificant in adult rats. TFAE fell in the jejunal isografts, whereas it increased in the ileum. MG-P remained as the major pathway in the implanted jejunum and ileum. Our studies suggest that luminal contents are probably the most important modulator for the development and maintenance of intestinal fatty acid esterification, and "fetal programming" manifested by changes in fatty acid esterification mechanisms in the isografts is less important.

Animals↗
PubMed1978

Effect of cortisone or triiodothyronine administration to pregnant rats on lysosomal hydrolases in fetal forebrain and cerebellum.

Triiodothyronine injected daily to pregnant rats for the last week of gestation (50 microgram/100 g b.wt) increased the specific activities of 5 acid glycosidases in the fetal forebrain and cerebellum. Cortisone (50 mg/100 g b.wt) administered in the same period had no effect on cerebellum acid hydrolases, but decreased their activity in the forebrain.

Animals↗
PubMed1978

Prenatal development of acid beta-glycosidases in the rat liver, effect of triiodothyronine or cortisone administered to pregnant rats.

We have found that acid beta-galactosidase, beta-glucuronidase and N-acetyl-beta-glucosaminidase in the rat fetal liver increase during the last week of pregnancy. These enzyme activities were influenced by treatment of pregnant rats (daily from day 16) with L-tri-iodothyronine (20 or 50 microgram/100 gm b.w.) or cortisone acetate (10 or 50 mg/100 gm b.w.) as studied in their fetuses obtained on day 22 by caesarian section.

Acetylglucosaminidase↗
PubMed1978

Late effects of premature weaning to different diets in the rat.

Female rats were prematurely weaned on the 18th postnatal day to a high fat (HF) or high carbohydrate (HG) diet. Twelve days later they were all given free access to a cereal based stock diet. When aged 10 months, they were all fed an atherogenic diet for the next 2 months and were then killed. Blood cholesterol levels were higher in the HG group at 11 months but not 1 month later. After 2 months of feeding the atherogenic diet, injected 14C-cholesterol disappeared more slowly from the HF group during the first 24 hours after injection but more rapidly during the next 48 hours than the HG group. At that time, serum glucagon levels in the HF group had doubled but remained unchanged in the HG group. Serum insulin levels decreased significantly during that same period in the HF group but not the HG group. Consequently, the I/G molar ratio was lower in the HF than the HG group after 2 months of feeding the atherogenic diet. At 12 months, selected enzyme activities in white adipose tissue and liver did not differ between the two groups, except for phosphoenolpyruvate carboxykinase, the activity of which was higher in the HG

Animal Nutritional Physiological Phenomena↗
PubMed1977

Activities of acid hydrolases in fibroblasts from normal and cystinotic children.

A study of the lysosomal hydrolases bete-galactosidase, beta-glucuronidase, N-acetyl-beta-D-glucosaminidase, and arylsulphatases A and B has been carried out on fibroblasts cultured from seven patients with cystinosis and eight control subjects. beta-Galactosidase activity was found to be consistently lower in cells derived from cystinotics, while the other enzymes studied showed no significant differences between normals and cystinotics.

Arylsulfatases↗
PubMed1977

Prenatal induction of sucrase activity in rat jejunum.

Daily application of cortisone acetate (10mg/100g body wt.) or L-tri-iodothyronine (20 microng/100g body wt.) to female rats in the last (third) week of pregnancy elicits a precocious appearance of jejunal sucrase in their foetuses.

Animals↗
PubMed1977

Comparison of postnatal development of several acid glycosidases in the rat forebrain and cerebellum.

Changes of activity of several glycosidases (beta-galactosidase, beta-glucuronidase, N-acetyl-beta-D-glucosaminidase, alpha-D-mannosidase and alpha-L-fucosidase) were compared in the forebrain and cerebellum during postnatal development of the rat. Detailed analysis of the data showed similarities, but also substantial differences in their development in both organs. This is interpreted as an indication of the presence of common regulatory mechanisms, as well as of other factors which differently influence development of the glycosidases studied in both CNS parts.

Acetylglucosaminidase↗
PubMed1977

Effect of cortisone or L-triiodothyronine administration to pregnant rats on the activity of fetal intestinal disaccharidases and lysosomal acid beta-galactosidase.

Activities of maltase, sucrase, lactase and acid-beta-galactosidase were studied in jejunum and ileum of term rat fetuses obtained by cesarian section. Female rats were either untreated or injected daily in the last (3rd) week of pregnancy with cortisone acetate (10 or 50 mg/100 g body weight) or L-triiodothyronine (20 or 50 microgram/100 g body weight). Two other control groups were injected with appropriate solvents. Cortisone or T3 treatment to mothers increased sucrase and maltase activity in jejunum and ileum of the offspring. Generally, higher doses of hormone were more effective. Lactase activity was increased by 25% in the jejunum by the higher dose of cortisone. Both doses of cortisone increased ileal lactase. Jejunal acid-beta-galactosidase activity was decreased in fetuses of T3-treated mothers.

Animals↗
PubMed1977

Thyroxine-evoked decrease of jejunal lactase activity in adult rats.

Daily administration of L-thyroxine (20 micrograms or 200 micrograms/100 g body weight) to adult male rats decreased jejunal lactase activity by 35% after 2-, 3-, 4- and 10 days. Four days of injections of D-thyroxine (200 micrograms/100 g body weight/day) produced a similar decrease of lactase activity. Sucrase activity was uninfluenced except for a 30% increase after daily injections of L-thyroxine (200 micrograms/100 g body weight) for 10 days. Acid beta-galactosidase activity was unaffected by either D- or L-thyroxine.

Animals↗