Biomedical subjects

L J Brant

Publications and source records attributed to L J Brant.

40 records · Page 3Linked to original sources

PubMed1984

Growth and hematological changes in the Eskimo children of Wainwright, Alaska: 1968 to 1977.

The growth and hematological status of all 152 Eskimo children of Wainwright, AK observed in 1977 are reported and compared with the respective status of the children living there in 1968. Fifty-two children (34%) in the 1977 study were also in the 1968 study. Comparison of height data observed in 1977 with those observed in 1968 reveals that male children less than 11 yr of age and female children ages 3 to 9 yr showed a significant improvement in stature (p less than 0.05). At the same time, an improvement in nutrition was observed among the children in 1977 as evidenced by the marked decrease in anemia for children under 6 yr (p less than 0.001). These changes in growth and hematological status have occurred during a time in which health services were improved, a supplemental nutrition program was instituted, and subsistence food gathering remained high. These changes underscore the contribution of environmental factors rather than of genetic variability to the growth potential of these children.

Adolescent↗

PubMedDate not supplied

Mixed-effects regression models for studying the natural history of prostate disease.

Although prostate cancer and benign prostatic hyperplasia are major health problems in U.S. men, little is known about the early stages of the natural history of prostate disease. A molecular biomarker called prostate specific antigen (PSA), together with a unique longitudinal bank of frozen serum, now allows a historic prospective study of changes in PSA levels for decades prior to the diagnosis of prostate disease. Linear mixed-effects regression models were used to test whether rates of change in PSA were different in men with and without prostate disease. In addition, since the prostate cancer cases developed their tumours at different (and unknown) times during their periods of follow-up, a piece-wise non-linear mixed-effects regression model was used to estimate the time when rapid increases in PSA were first observable beyond the background level of PSA change. These methods have a wide range of applications in biomedical research utilizing repeated measures data such as pharmacokinetic studies, crossover trials, growth and development studies, aging studies, and disease detection.

Aged↗

PubMedDate not supplied

Longitudinal evaluation of prostate-specific antigen levels in men with and without prostate disease.

OBJECTIVE: To evaluate longitudinal changes in prostate-specific antigen (PSA) levels in men with and without prostate disease. DESIGN: Case-control study of men with and without prostate disease who were participants in a prospective aging study. SETTING: Gerontology Research Center of the National Institute on Aging; the Baltimore (Md) Longitudinal Study of Aging. PATIENTS: Sixteen men with no prostate disease (control group), 20 men with a histologic diagnosis of benign prostatic hyperplasia (BPH), and 18 men with a histologic diagnosis of prostate cancer. OUTCOME MEASURES: Multiple PSA and androgen determinations on serum samples obtained from 7 to 25 years prior to histologic diagnosis or exclusion of prostate disease. RESULTS: Changes in androgen levels with age did not differ between groups. Control subjects did not show a significant change in PSA levels with age. There was a significant difference in the age-adjusted rate of change in PSA levels between groups (prostate cancer greater than BPH greater than control; P less than .01). At 5 years before diagnosis when PSA levels did not differ between subjects with BPH and prostate cancer, rate of change in PSA levels (0.75 micrograms/L per year) was significantly greater in subjects with prostate cancer compared with control subjects and subjects with BPH. Also, rate of change in PSA levels distinguished subjects with prostate cancer from subjects with BPH and control subjects with a specificity of 90% and 100%, respectively. CONCLUSIONS: The most significant factor affecting serum PSA levels with age is the development of prostate disease. Rate of change in PSA levels may be a sensitive and specific early clinical marker for the development of prostate cancer.

Aged↗

PubMedDate not supplied

Factors affecting streptococcal colonization among children in selected areas of Alaska.

The epidemiology of streptococcal disease affecting 706 Alaskan Eskimo children was investigated by analysis of data on throat cultures obtained during a long-term surveillance program begun in 1971. A binary variable multiple-regression model was used to study the association between streptococcal colonization of these children and six potential risk factors: age, sex, number of children in household, region, health-aide rating, and colonization rate for each child the previous year. Factors found to be significantly associated with streptococcal colonization included age, past colonization, competence of local health-aide in providing care, and health-care region. Age varied most in the standardized colonization ratio (percentage of corresponding adjusted rate to overall crude colonization rate), ranging from 122 percent for children 3--6 years old to 67 percent for children 13--18 years old. The number of children in over-crowded homes and a child's sex were not apparently important. The method of analysis can be used to provide health-care planners with a simple means of identifying potentially important areas of concern for planning effective and economical health-care strategy.

Adolescent↗