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Biomedical subjects

M Savage

Publications and source records attributed to M Savage.

At least 73 records · Page 4Linked to original sources

Effect of hypertension and physical training on the morphology of the kidney with special reference to the juxtaglomerular cells.

Changes in blood pressure levels, renal structure and degree of granulation of the juxtaglomerular cells in Dahl S rats fed a normal or high salt diet are reported. The effect of physical training on the hypertensive state of these animals has also been described. Animals fed a high salt diet demonstrated increased blood pressure levels and decreased juxtaglomerular indices when compared with rats fed a normal diet. The extent of renal damage in these animals was observed to be proportional to the amount of sodium in the diet. Physical training, however, brought about a 15-25% reduction in blood pressure levels and decreased renal damage in Dahl S rats fed a normal or high salt diet. The mean juxtaglomerular index was observed to be 30% higher in trained animals fed a normal diet compared with non-trained controls. It is concluded that physical training helps minimize pathological changes in the kidney and effects a reduction in blood pressure levels in hypertensive Dahl S rats.

Animals↗

Influence of tissue compressibility on calibration for strain-gauge plethysmography.

Strain gauges employed in plethysmography for determination of limb blood flow tend to counter the expansion of the limb during venous occlusion. Traditionally a mechanical calibration is performed in situ to compensate for tissue compressibility. Greenfield, Whitney, and Mowbray stated that, otherwise, large errors would result (Br. Med. Bull. 19: 101-109, 1963). Nonetheless, not all of the recent reports on skin blood flow in humans have been based on a calibration procedure that corrects for tissue compressibility. To evaluate the significance of this problem, we developed a new strain-gauge holder that made possible frequent, reproducible, stretching of a single-strand Whitney gauge in situ. We compared the apparent sensitivity thus obtained to electrical or bench mechanical determinations. We independently determined tissue compressibility by recording limb circumference as tension in a circumferential tube was varied. Both techniques showed that tissue compressibility is a small source of error (5%) and that compressibility decreases during occlusion. Therefore the cumbersome holder and potential artifacts associated with the traditional technique need not be tolerated. We also investigated the consequences of nonuniform tension distribution and temperature changes; practical considerations for dealing with these are discussed.

Adult↗

The use of scintigraphic studies in mid-ventricular obstructive cardiomyopathy to rule out pseudoaneurysm.

A "pseudo-pseudo" aneurysm of the left ventricle due to mid-ventricular obstruction from asymmetric septal hypertrophy is presented. A case of mid-ventricular hypertrophic obstructive cardiomyopathy (MVHOCM) was evaluated by means of echocardiography, angiocardiography, gated cardiac blood pool scanning, and a TI-201 myocardial scan. The gated cardiac blood pool scan appearance of MVHOCM is similar to pseudoaneurysm of the left ventricle. TI-201 myocardial imaging, however, was able to distinguish between MVHOCM and pseudoaneurysm of the left ventricle.

Aged↗

Physiological characteristics of high-ability prepubescent wrestlers.

The present study compared the physiological responses to exercise, the anaerobic fitness, and the body composition of high-ability prepubescent wrestlers and normally active boys. The wrestlers (N = 15, mean age +/- S.D. = 11.3 +/- 0.30 yr) were recruited to participate in a summer wrestling camp. Their wrestling experience averaged 3.0 +/- 1.63 yr, during which time they won 78 +/- 10.5% of the matches. The comparison boys (N = 13, 10.7 +/- 0.36 yr) were volunteers from a local Boy's Club. Each subject performed a graded treadmill exercise test (Bruce protocol) and an anaerobic cycle ergometer test. Additionally, body composition was assessed using densitometry and skinfolds. There were no differences (P greater than 0.05) between the wrestlers and the comparison subjects for age or height. The wrestlers exercised for 1.5 min longer on the treadmill and obtained a higher VO2max (54.0 +/- 1.15 ml X min-1 X kg-1, P less than 0.05) than the comparison subjects (45.6 +/- 2.10 ml X min-1 X kg-1). Also, the wrestlers had higher anaerobic test scores, greater body densities, and lower subcutaneous fat totals at all sites than the normally active boys. These data indicate that the favorable fitness and body composition scores found previously for more mature wrestlers are already present in prepubescent wrestlers.

Adipose Tissue↗

The body composition and physical dimensions of 9- to 12-year-old experienced wrestlers.

Body composition and physical dimensions were compared between 23 young, experienced wrestlers (mean age +/- SE = 11.0 +/- 0.21 yr) and 23 school children (11.2 +/- 0.24 yr). The wrestlers were among the best wrestlers from local wrestling clubs and averaged 2.7 (+/- 0.27) yr of experience. They had won 72% (+/- 1.8%) of the total 75 (+/- 9.1) matches. The comparison group consisted of volunteers from local elementary schools. Standard densitometric and anthropometric techniques were used to measure the body composition and physical dimensions of each group. The wrestlers were 4 kg lighter (P less than 0.05) and had a smaller percent fat than the comparison group (13.3 +/- 0.66% and 20.0 +/- 1.13%, respectively). The weight difference between groups was due to the larger fat weight of the comparison group since lean weight differed by only 0.8 kg. Fat differences were also reflected in the larger skinfolds and "fat" circumferences of the comparison group. No group differences were noted in diameters. It is concluded that compared to other children young experienced wrestlers have similar skeletal structures and lean body weights. The comparison group possessed more body fat.

Adipose Tissue↗

Genetic insertion of nuclear spin labels in the lac repressor.

A general strategy for the insertion of nuclear spin labels throughout the sequence of a protein is illustrated with the Escherichia coli lac repressor. Examples are shown where the 19F nucleus is incorporated using 3-fluorotyrosine, as well as the selective insertion of additional protons. These selectively inserted nuclei give additional resonances in the respective NMR spectra that can be used to probe the structure and function of the proteins.

Amino Acid Sequence↗

Thymidine kinase activity is reduced in the developing staggerer cerebellum.

In the mouse cerebellar mutant staggerer, thymidine kinase levels do not increase developmentally at ages when the wild-type level is high. Mixing experiments show that this effect is not due to an endogenous inhibitor of the enzyme. Both the Km and the susceptibility of the thymidine kinase to nucleotide inhibitors are unaltered in the mutant animals, suggesting that the enzyme is not induced in the mutant.

Aging↗

Immediate response of 5-methoxytryptophol in the circulation to hypoglycaemic stress induced by insulin.

Pineal indoles have been shown to affect the release of anterior pituitary hormones but details of the interrelationships are lacking. Using a new gas chromatography-mass spectrometry (g.c.-m.s.) assay the concentration of 5-methoxytryptophol (ML) was measured in plasma samples obtained from 16 children undergoing investigation of pituitary function for delayed growth. All the children received an insulin tolerance test (ITT) to study their endocrine response to stress. Some children received luteinizing hormone releasing hormone (LH-RH) and/or thyrotrophin releasing hormone (TRH). The change in concentration of ML during an ITT was similar to the change in concentration of blood sugar; a drop at 20 min followed by a rise at 30 min. This was not significantly altered by the administration of LH-RH or TRH, nor was there a different pattern of response in children who were deficient in growth hormone as opposed to those with idiopathic delayed growth. The fall in concentration of ML with stress may mediate the increased secretion of pituitary hormones. Alternatively, the pineal gland may respond directly to insulin.

Adolescent↗

DNA-protein interactions of the rat liver non-histone chromosomal protein.

Native rat liver NHC protein-DNA interactions have been investigated by use of a nitrocellulose filter assay sensitive in detection of protein-DNA complexes. Optimal conditions for DNA-protein interactions occurs at low ionic strength conditions (110 mM phosphate buffer). A fraction of NHC proteins was enriched 25-fold by their affinity for rat DNA immobilized on cellulose columns under these conditions. At higher ionic strength (260 mM-0.04M phosphate buffer and 0.15 M sodium chloride), this fraction binds approximately sevenfold less to rat DNA but with a substantial increase in stability of the complexes. Equilibrium competition experiments indicate that at the higher ionic strength there is a considerable DNA sequence specificity of the rat DNA binding NHC protein. Since rat DNA contains three components as defined by their reassociation kinetics: single copy DNA (C0t1/2pure = 1.6 times 103); middle repetitive DNA (C0t1?1PURE = 1.1); and highly repetitive (C0t1/2pure smaller than 0.02). The two former were isolated and employed in the DNA binding assays. At the high ionic strength criterion, the rat DNA binding NHC proteins showed a substantial preference for a subset of middle repetitive DNA sequences. This suggests a preferential interaction between a class of NHC proteins and a class of middle repetitive DNA sequences.

Animals↗

Selective interaction of Neisseria gonorrhoeae and Candida albicans and its possible role in clinical specimens.

A study of 27 clinical specimens from which Neisseria gonorrhoeae and Candida albicans were isolated simultaneously indicated that 44% of the gonococcal isolates were resistant to inhibition by the C. albicans with which they were found and an additional 33% were totally resistant to inhibition by all C. albicans tested. All 27 C. albicans showed inhibitory activity against standard indicator strains of N. gonorrhoeae.

Antibiosis↗