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Biomedical subjects

N W Shock

Publications and source records attributed to N W Shock.

At least 19 recordsLinked to original sources
PubMed1987

Hypertension and the kidney.

The purpose of this study was to confirm, using longitudinal observations in a normal population, that the rate of decline in renal function (creatinine clearance) is inversely correlated with blood pressure. The negative regression coefficients plotting individual rates of decline over time (Bcr) against mean blood pressures (MBP) were highly significant (p less than 0.001) for all subjects and subjects in category 3 (normals). Although the Bcr also decreases significantly with age and MBP increases with age suggesting this might be an age effect, a multiple regression analysis shows that both MBP and age as independent variables exert statistically significant effects on Bcr, the dependent variable.

Adult↗
PubMed1985

Longitudinal studies on the rate of decline in renal function with age.

Serial creatinine clearances (5 to 14 studies) were obtained for 446 normal volunteers in the Baltimore Longitudinal Study of Aging followed between 1958 and 1981. When those subjects with possible renal or urinary tract disease and subjects on diuretics and antihypertensives were removed from the study, leaving a group of 254 "normal" subjects, the mean decrease in creatinine clearance was 0.75 ml/min/year. The slopes of the creatinine clearance vs. time fell into a normal (Gaussian) distribution around this mean. One third of all subjects followed had no absolute decrease in renal function (positive slope of creatinine clearance vs. time) and there was a small group of patients who showed a statistically significant increase (P less than 0.05) in creatinine clearance with age.

Adult↗
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↗