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Biomedical subjects

R Grace

Publications and source records attributed to R Grace.

51 records · Page 3Linked to original sources
PubMed1985

Iron deficiency in the rat: effects on energy metabolism in brown adipose tissue.

Mitochondria were prepared from the brown adipose tissue of control rats and animals made iron deficient by means of a low iron diet. The specific activities of the mitochondrial electron transport system (NADH, succinate and alpha-glycerophosphate oxidase activities) were markedly and significantly reduced in preparations of brown adipose tissue from the iron-deficient rats as compared with preparations from the control animals. In contrast, concentrations of the cytochrome pigments a + a3, and c + c1 were normal and cytochrome b was slightly reduced (18%) in the mitochondrial preparations from the iron-deficient animals. Treatment of the iron-deficient animals with triiodothyronine significantly increased the amount of brown fat present per kilogram of body weight in both control and iron-deficient rats, but did not significantly affect the specific activities of the mitochondrial electron transport system.

Adipose Tissue, Brown↗
PubMed1984

Iron deficiency in the rat: effects on oxidative metabolism in distinct types of skeletal muscle.

Studies performed on iron-deficient and control rats demonstrated that oxidative energy production (phosphorylation) by mitochondria from iron-deficient red and intermediate skeletal muscles was greatly reduced with pyruvate-malate, succinate, and alpha-glycerophosphate as substrates. Although phosphorylation was also decreased in iron-deficient white skeletal muscle with succinate and pyruvate-malate as substrates, no change was found with alpha-glycerophosphate as substrate.

Anemia, Hypochromic↗
PubMed1983

Iron deficiency in the rat: biochemical studies of fetal metabolism.

The effects of dietary-induced iron deficiency on fetal and maternal metabolism were studied in the rat. Concentrations of phenylalanine, but not tyrosine, were significantly elevated in plasma from iron-deficient maternal and fetal rats at day 20 of gestation with individual fetal plasma levels of phenylalanine as high as 10 mg per 100 ml. Concentrations of total 5-hydroxyindole compounds were significantly decreased in brain tissue from iron-deficient fetuses (day 20 of gestation), suggesting that synthesis of the compounds may be inhibited by iron deficiency. Mitochondrial NADH oxidase activity was markedly decreased (60%) in homogenates of fetuses at day 14 of gestation and may account for the high fetal resorption rate and small fetal size observed in the rat in iron deficiency.

Animals↗
PubMed1975

Studies of the development of congenital anomalies in rats. III. Effects of inhibition of mitochondrial energy systems on embryonic development.

Pregnant rats were treated with various inhibitors of mitochondrial oxidative energy metabolism and with lowered oxygen tension, and the embryo fetuses examined for the occurrence of congenital malformations and for changes in enzymatic activities. Treatment with all agents tested resulted in the production of skeletal anomalies. Sodium phenobarbital was the most teratogenic of the drugs tested and produced a high incidence of malformations which included cleft palate, tail anomalies, spinal retroflexion, domed head, and facial hypoplasia. Diphenylhydantoin produced a low incidence of syndactyly and oligodactyly. In addition to its effects on fetal growth and development chloramphenicol appeared to interfere with implantation. Tissue preparations from embryos exposed to sodium phenobarbital and chloramphenicol showed markedly lowered levels of DPNH oxidase activity. Cytochrome oxidase activity was also markedly lowered in the preparations from chloramphenicol-exposed embryos. Enzyme activities in preparations from embryos exposed to malonate and diphenylhydantoin appeared unaffected, although the drugs are strong inhibitors of electron transport in vitro; the lack of apparent effect may be due to the fact that both drugs do not bind to the enzyme preparations and were diluted 100- to 200-fold during preparation and assay of the tissue homogenates.

Abnormalities, Drug-Induced↗
PubMed1974

The dynamic structure of a flat small intestinal mucosa studied on the explanted rat jejunum.

Small pieces of jejunum with an intact blood supply were explanted to the anterior abdominal wall in rats. Six weeks after explantation the mucosa appeared totally flat in many areas, both histologically and under the dissecting microscope. The structure of the flattened mucosa was shown to be identical to that in coeliac disease with hypertrophied intervillous ridges. A dynamic study with tritium-labelled thymidine demonstrated a considerably increased turnover in the flat mucosa with some disorganization of cell production and migration.

Animals↗
PubMedDate not supplied

Thromboprophylaxis.

Thromboembolic disease causes significant morbidity and mortality. This article evaluates those patients at risk and the thromboprophylactic strategies that may be employed.

Anticoagulants↗