Search PubMed⌕ Search

Biomedical subjects

J Metcalfe

Publications and source records attributed to J Metcalfe.

At least 109 records · Page 6Linked to original sources
PubMed1976

Failure of carbon monoxide to induce myocardial infarction in cholesterol-fed cynomolgus monkeys (Macaca fascicularis).

Twenty-six adult female cynomolgus monkeys (Macaca fascicularis) were randomly assigned to four groups which were fed on a standard laboratory diet or a semipurified diet containing cholesterol. In two of the groups, the monkeys were exposed intermittently to CO throughout the day for 14 months; the control animals breathed room air. No myocardial infarctions were observed, and the ECG showed a transitory injury current in only one animal. No differences in plasma cholesterol levels or in aortic and coronary atherosclerosis could be attributed to CO exposure.

Animals↗
PubMed1975

Oxygen consumption at rest and during exercise in pregnancy.

The oxygen consumption (Vo2) of 12 normal women was measured at monthly intervals during pregnancy and 2, 6 and 12 weeks and 6 months postpartum. At each study session measurements were made sitting at rest, during standard steady-state exercise on a bicycle ergometer, and for 10 minutes of recovery. A significant increase in exercise Vo2 was observed in late pregnancy when compared to paired postpartum values. The oxygen debt incurred by standard exercise was also greater in late pregnancy than 12-14 weeks postpartum.

Female↗
PubMed1975

Ventilation during rest and exercise in pregnancy and postpartum.

The expiratory minute volume (Ve), respiratory frequency (f), tidal volume (VT), carbon dioxide production (Vco2), and end-tidal carbon dioxide concentration (FETCO2) and pressure (PETCO2) were measured at monthly intervals in 12 normal women during pregnancy and two, six and 12 weeks, and six months postpartum. At eacy study, measurements were made sitting at rest and during steady-state exercise at 306 kpm/min on a bicycle ergometer. During pregnancy, a significant increase in VE occurred, both at rest and during exercise, due to a significantly greater VT. Although VCO2 was significantly increased at rest throughout pregnancy and with exercise in late pregnancy, the respiratory exchange ratio (R) was not significantly altered during pregnancy. The FETCO2 was lower during pregnancy than postpartum, both at rest and during exercise. The ventilatory equivalent for oxygen (VE/VO2) was greater at rest near term and during exercise throughout pregnancy. However, resting physiologic dead space increased during pregnancy. Alveolar ventilation (VA) was calculated on the basis of three alternative assumptions: (1) that PETCO2 during exercise accurately reflects mean alveolar PCO2; (2) that the physiological dead space does not change during exercise; and (3) that mean alveolar PCO2 does not change from rest to exercise. Exercise VA, calculated on the basis of any of these three assumptions, is greater during pregnancy than postpartum.

Carbon Dioxide↗
PubMed1975

Hepatic albumin and urea synthesis: The mathematical modelling of the dynamics of [14C]carbonate-derived guanidine-labelled arginine in the isolated perfused rat liver.

A mathematical model was constructed to define the dynamics of incorporation of radioactivity into urea carbon and the guanidine carbon of arginine in plasma albumin after the rapid intraportal-venous administration of Na214CO3 in the isolated perfused rat liver. 2. The model was formulated in terms of compartmental analysis and additional experiments were designed to provide further information on subsystem dynamics and to discriminate between alternative model structures. 3. Evidence for the rapid-time-constant of labelling of intracellular arginine was provided by precursor-product analysis of precursor [14C]carboante and product [14C]urea in the perfusate. 4. Compartmental analysis of the dynamics of newly synthesized urea was based on the fate of exogenous [13C]urea, endogenous [14C]urea and the accumulation of [12C]urea in perfusate water, confirming the early completion of urea carbon labelling, the absence of continuing synthesis of labelled urea, and the presence of a small intrahepatic urea-delay pool. 5. Analysis of the perfusate dynamics of endogenously synthesized and exogenously administered [6-14C]arginine indicated that although the capacity for extrahepatic formation of [14C]-urea exists, little or no arginine formed within the intrahepatic urea cycle was transported out of the liver. However, the presence of a rapidly turning-over intrahepatic arginine pool was confirmed. 6. On the basis of these subsystem analyses it was possible to offer feasible estimations for the parameters of the mathematical model. However, it was not possible to stimulate the form and magnitude of the dynamics of newly synthesized labelled urea and albumin which were simultaneously observed after administration of [14C]carbonate on the basis of a preliminary model which postulated that both products were derived from a single hepatic pool of [16-14C]arginine. On the other hand these observed dynamics could be satisfied to a two-compartment arginine model, which also provided an explanation for discrepancies observed between albumin synthesis measured radioisotopically and immunologically. This was based on a relative overestimation of [14C]urea specific radioactivity resulting from the rapid dynamics of [14C]carbonate and the [14C]urea subsystem relative to the labelled albumin subsystem. The effects of arginine compartmentalization could be minimized in the model by minor slowing of the rate of [14C]carbonate turnover or by constant infusion of [14C]carbonate, both of which permitted valid determination of albumin-synthesis rates.

Animals↗
PubMed1975

Normal functions of the thyroid gland of the pygmy goat.

Normal values were obtained for blood serum PBI, T3 index. T4, and cholesterol in a colony of pygmy goats (n equal to 55) of mixed sex and age. Serum PBI values averaged 8.1 plus or minus 1.2 mug/dl with no significant sex differences. The mean T3 index and T4 value were 1.1 plus or minus 0.1 and 7.2 plus or minus 1.1 mug/dl, respectively, with no sex differences. The mean serum cholesterol value was 90.0 mg/dl, with sex differences apparent. Serum cholesterol averaged 84.9 mg/dl (n equal to 44) for females and was significantly higher in intact males (97.4 mg/dl; n=8) and significantly lower in castrate males 69.2; n=6. There was a consistent and significant increase in cholesterol values with age in females, an unexplained phenomenon also observed in humans. There was no evidence of thyroid malfunction in the animals studied.

Age Factors↗
PubMed1975

Serum biochemical and electrophoretic values from four deer species and from pronghorn antelope.

Serums from 4 species of deer and 1 species of antelope were analyzed for various components in order to define an animal disease model for sickle cell disease in people. Animal species included black-tailed deer (Odocoileus hemionus columbianus), mule deer (Odocoileus hemionus), sika deer (Cervus nippon nippon), fallow deer (Dama dama), and pronghorn antelope (Antilocapra americana). The mean serum values for total bilirubin, total protein, albumin, creatinine, urea nitrogen, and electrolytes were similar in all species and were in the normal range for human beings. Cholesterol and uric acid values for all animals were lower than those for people. Alkaline phosphatase values in the 4 cervid species were higher than in the pronghorn antelope. Values for glutamic oxalacetic transaminase were lower in the cervids than in the pronghorn antelope. Lactic dehydrogenase values were similar in the 5 species. High activities for glutamic oxalacetic transaminase and lactic dehydrogenase in the 5 species probably related to muscle mass and great muscular activity.

Alkaline Phosphatase↗
PubMed1975

A proposed role for alpha1 macroglobulin in the promotion of alpha1 acute-phase globulin synthesis by the perfused rat liver.

The effects of intravenously administered rat alpha1 macroglobulin (alpha1M), alone and in combination with pancreatic trypsin, on the synthesis of alpha1 acute-phase globulin (alpha1AP globulin) have been measured in the isolated perfused rat liver 24 h after injection. Maximum promotion (approximately five-fold) of alph1AP globulin synthesis was observed after administration of alpha1M complexed with trypsin or alpha1M alone, which after purification had lost most of its trypsin-protein-esterase (T.P.E.) activity. Slightly lesser but still significant degrees of enhancement (approximately four-fold) of alpha1AP globulin synthesis resulted from the injection of alpha1M alone or complexed with trypsin, which after purification had retained sitnificant T.P.E. activity. All these responses were greater than those generated by injection of trypsin or plasma alone, or rabbit plasma complexed with trypsin. However, the synthetic response did not reach the maximum rate observed 24 h after an intramuscular injection or sterile turpentine. An hypothesis is proposed for the role of alpha1 macroglobulin (and its homologue in man, alpha2 macroglobulin) in the mediation of the acute-phase synthetic response by the liver. This predominantly intravascular glycoprotein serves as the principal circulatory porteinase binder. Proteinases released in response to tissue injury, necrosis or inflammation would be bound and inactivated by alpha1M, and in turn the alpha1M-proteinase complex would stimulate the liver to synthesize a number of acute-phase proteins. Certain of these, e.g. alpha2 acute-phase globulin also possess proteinase binding activity and, being of low molecular weight, would be more effective than alpha1M in the inactivation of released tissue enzymes at extravascualr sites. The data presented in this paper are compatible with this biphasic role for plasma proteinase inhibitors in the biological response to injury.

Albumins↗