Search PubMed⌕ Search

Biomedical subjects

N W Shock

Publications and source records attributed to N W Shock.

At least 37 records · Page 2Linked to original sources
PubMed1978

Current publications in Gerontology and Geriatrics.

The subject categories are those in A Classified Bibliography of Gerontology and Geriatrics by Nathan W. Shock, published by Stanford University Press, Stanford, California (1951). Only major headings are used and the Roman numerals correspond to those given in the bibliography. Insofar as possible, references are classified according to organ systems. Thus, most of the material on Geriatrics will be found under the organ system involved in the disease. Cross references are indicated by numbers at the end of each section. When available, abstract references are given (B.A.-Biological Abstracts. P.A.-Psychological Abstracts, and P.I.-Population Index). Abbreviations for journals are those in A World List of Scientific Periodicals Published in the years 1900-1933, 2nd Edition. For journals not listed, abbreviations were devised to the general rules used in the above source. It is impossible to cover all journals and list all papers concerned with aging and the aged. Authors and publishers are requested to call attention to publications or to send reprints to the Gerontology Research Center, Baltimore City Hospitals, Baltimore, Maryland 21224.

Bibliographies as Topic↗
PubMed1977

Current publications in gerontology and geriatrics.

THE SUBJECT categories are those in A Classified Bibliography of Gerontology and Geriatrics by Nathan W; Shock, published by Stanford University Press, Stanford, California (1951). Only major headings are used and the Roman numerals correspond to those given in the bibliography. Insofar as possible, references are classified according to organ systems. Thus, most of the material on Geriatrics will be found under the organ system involved in the disease. Cross references are indicated by numbers at the end of each section. When available, abstract references are given (B.A.--Biological Abstracts. P.A.--Psychological Abstracts, and P.I.-Population Index). Abbreviations for journals are those in A World List of Scientific Periodicals Published in the years 1900-1933; 2nd Edition. For journals not listed, abbreviations were devised to the general rules used in the above source. It is impossible to cover all journals and list all papers concerned with aging and the aged. Authors and publishers are requested to call attention to publications or to send reprints to the Gerontology Research Center, Baltimore City Hospitals, Baltimore, Maryland 21224.

Bibliographies as Topic↗
PubMed1977

Increased dynamic stiffness of trabeculae carneae from senescent rats.

Dynamic stiffness was measured in both adult and senescent Wistar rats using sinusoidal length perturbations from 17 to 40 Hz, superimposed on isometric contractions at low and below Lmax. The slope of the stiffness-tension relationship was found to be increased in senescent muscles of both sexes and at two different temperatures. The age dependence of the slope was independent of resting muscle length. The slope also exhibited frequency dependence and hysteresis that indicates the presence of viscoelasticity during activation. No age dependence was seen in peak active tension, peak dT/dt, or resting stiffness. The findings of this study, taken together with other studies that have shown a decreased shortening ability in the senescent muscle, explain in part the maintenance of active tension development in the face of decreased shortening ability associated with the senescent muscle.

Aging↗
PubMed1976

Age differences in vitamin B6 status of 617 men.

The effect of age on vitamin B6 metabolism was studied in 617 community-dwelling subjects, ages 18 to 90. These are, for the most part, clinically healthy, educated men whose intake of nutrients is not limited by economic factors. Plasma pyridoxal phosphate (PLP) was used as the primary criterion of vitamin B6 status. About one-third of the subjects were taking supplementary vitamins on their own initiative. The amount of pyridoxine-HCl varied from 0.1 to 105 mg/day. The average plasma PLP of the men not taking a supplement (N = 414) was 12.3 +/-0.3 ng/ml, with 25% of the values below 7.5 ng/ml and 7% below 5 ng/ml. There was a statistically significant decrease in plasma PLP with age of 0.9 ng/ml per decade. For those taking a supplement, the average plasma PLP was 20.5 +/- 1.0 ng/ml, with only 8% of the values below 7.5 ng/ml and none below 5 ng/ml. Glutamic-oxaloacetic transaminase activity in plasma (PGOT) and erythrocytes (EGOT) was determined on all subjects. The ratio of EGOT with in vitro stimulation by PLP to EGOT actual (alpha-EGOT) was also studied. These studies provide the most extensive normative data on vitamin B6 status available on men in the adult years of life.

Adolescent↗
PubMed1976

The effect of age on creatinine clearance in men: a cross-sectional and longitudinal study.

Standard true 24-hour creatinine clearance determinations were performed on 884 subjects of the Baltimore Longitudinal Study. On the basis of clinical data, subjects were placed in categories indicating the presence of specific diseases or medications which might alter glomerular filtration rate. Subjects not included in these categories were considered normal (N=548). In the normals, cross-sectional analysis by 10-year age groups showed a progressive linear decline in clearance from 140 ml/min/1.73m2 at age 30 to 97 at age 80. Three or more serial clearances were obtained at 12- to 18-mo. intervals on 293 normal subjects. These longitudinal data showed an acceleration of the rate of decline in creatinine clearance with advancing age. The decrease in creatinine clearance with age seen in this study represents true renal aging and is not secondary to diseases which become increasingly prevalent in the elderly. A nomogram constructed from these data provides normative age-corrected standards for creatinine clearance.

Adolescent↗
PubMed1976

The influence of age on the renal response to water deprivation in man.

Alterations in urine concentrating ability with age were examined in 98 active community-dwelling volunteers (aged 20-79 years) who were free from evidence of diseases known to adversely affect renal function. There was a significant decrease in urine osmolality reached after 12 h dehydration with advancing age, which could not be correlated with the age-related decline in creatinine clearance. A significant age-related diminution in the ability to conserve solute was also observed. This inability to conserve solute may result in diminished medullary tonicity and impaired urinary concentrating ability.

Adult↗
PubMed1975

Antipyrine metabolism in man: influence of age, alcohol, caffeine, and smoking.

Age has been shown to influence drug metabolism but effects of aging could be due to other variables that influence metabolism and differ with age. Plasma half-life and metabolic clearance rate of antipyrine were studied in 307 healthy male subjects, aged 18 to 92. Half-life was 16.5% longer and metabolic clearance rate was 18.5% less in a group of the older than in the younger subjects. Both caffeine and cigarette use were positively correlated with the rate of antipyrine metabolism. Multiple regression analysis showed that the effect of smoking was partially responsible for the age differences in antipyrine metabolism. Smoking explained 12% of the variance in metabolic clearance rate and age explained 3%. Our results suggest that studies attempting to quantify the effects of aging on drug metabolism must also take into account other factors that differ with age.

Adolescent↗
PubMed1975

Relationship of intramyocardial oxygen tension and epicardial ST segment changes following acute coronary artery ligation: effects of coronary perfusion pressure.

The relationship between the magnitude of epicardial ST-segment elevation and intramyocardial oxygen tension after coronary artery ligation was examined in 11 dogs at various coronary perfusion pressures. The ST map significantly reflected local intramyocardial oxygen tension, and the level of coronary perfusion pressure proved to be an important determinant of both local myocardial oxygen balance and the magnitude of ischaemic injury.

Animals↗