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Biomedical subjects

R Short

Publications and source records attributed to R Short.

At least 37 records · Page 2Linked to original sources

Phase I/II trial of superselective arterial 5-FU infusion with concomitant external beam radiation for patients with either anaplastic astrocytoma or glioblastoma multiforme.

From August 1987 through September 1989, 25 patients with either anaplastic astrocytoma (8 patients) or glioblastoma multiforme (17 patients) were entered into a Phase I trial of combined intra-arterial 5-fluorouracil (5-FU) and external beam radiation therapy. The intra-arterial 5-FU was given in a superselective, supraopthalmic fashion, in escalating doses from 200 mg to 600 mg on a weekly basis during the radiotherapy. Each patient received from 1-4 courses of 5-FU. Radiotherapy consisted of 5,000 rads in 25 fractions given to partial brain fields including the mass and surrounding edema plus a 3-cm margin as defined by computed tomography scan. There were a total of 4 significant acute complications out of a total of 70 infusions. These included 3 ischemic events of which 2 were transient. In addition, 1 patient experienced a cerebral bleed. No patients developed ocular complications. Electroencephalograms (EEGs) were performed immediately before and during 21 intra-arterial infusions. Two patients developed significant EEG changes during intra-arterial infusion, and both of these patients experienced untoward reactions. The remaining patients showed no EEG changes during their infusions. The median survival for patients with glioblastoma multiforme was 15 months. We believe the toxicity of superselective intra-arterial 5-FU infusion combined with external beam radiotherapy is acceptable. This type of treatment deserves further study.

Adult↗

Fingernail growth rate as a biomarker of aging in the pigtailed macaque (Macaca nemestrina).

Rate of fingernail growth (FNG) of the middle digit of the right hand was assessed in 46 healthy pigtailed macaques at approximately 6-month intervals for 4 to 6 years. Mean FNG for 24 females, ranging in mean age at measurement from 7 to 24 years, was 104 mu/day; the mean for 22 males, ranging from 7 to 20 years, was 111 mu/day. Longitudinal analysis showed that FNG declined in animals of both sexes and that the rate of decline (-4.8 mu/day/year) did not differ between them, i.e., the mean regression coefficients (beta) of the two sexes were significantly different from zero and not significantly different from each other. Results of cross-sectional analysis differed from those of longitudinal analysis in that the mean FNG appeared to be more rapid in males than in females, particularly in the older animals. Inter- and intra-individual variability in FNG did not increase with age. FNG appears to be an excellent functional marker of the rate of aging because the direction of change is essentially decremental, a significant degree of change can be detected in a few years, and the rate of change is relatively constant across the adult lifespan. In addition, measurement of FNG is innocuous, quantitative, inexpensive, and simple.

Aging↗

Constructing an instrument to measure the rate of aging in female pigtailed macaques (Macaca nemestrina).

To develop a battery of innocuous tests measuring individual differences in the rate of biological aging, longitudinal data were gathered on 28 biochemical, physiological, and morphological characteristics of 40 adult female pigtailed macaques. The change in each variable over time, i.e., the beta coefficient of linear regression, was calculated for each animal, and a matrix of correlations among the variables was constructed. Eight variables correlated well with the first principal component of the matrix. These variables (rate of fingernail growth, blood lymphocytes, mean corpuscular hemoglobin, immunoglobulin A, and serum sodium, chloride, total protein, and creatinine) represented the best subset of the potential biomarkers analyzed to produce an index covering a range of morphologic and functional systems that change with age. A similar set representing a wider range of systems and measured over a larger fraction of the life span should provide a valid index of an individual's rate of biological aging.

Aging↗

Ovarian cyclicity, hormones, and behavior as markers of aging in female pigtailed macaques (Macaca nemestrina).

Age-related differences in reproductive function were studied to identify variables suitable for a battery of noninvasive tests used to measure aging rate. Twenty-seven adult female pigtailed macaques, ranging in age from 8 to 31 years, were studied in a cross-sectional design. Perineal tumescence, menses, and activity in the home environment were recorded daily. Sexual behavior, when paired with unfamiliar males of three age groups, was observed six times in the early follicular phase of two ovarian cycles. Estradiol, LH, and FSH were measured twice during the same time period. Of the behavioral measures, mount, present, and activity were found to be lower in old than in young females. Of the physiological measures, ovarian cyclicity was less regular, estradiol was lower, and FSH and LH were higher in old compared to young females. Correlations between measures suggested two dimensions of reproductive function, a behavioral dimension and a physiological dimension.

Aging↗

Cross-sectional evaluation of potential biological markers of aging in pigtailed macaques: effects of age, sex, and diet.

The objective of our research was to establish a useful battery of innocuous tests suitable for detecting individual differences in biological aging rate in pigtailed macaques. Data were gathered from more than 60 animals of three age groups (8 to 9, 12 to 17, and 18 to 28 years olds) fed two diets differing in lipid, cholesterol, complex carbohydrate, refined sugar, and sodium chloride content. Candidate variables for an aging battery were identified in a cross-sectional analysis by performing a three-way analysis of variance (ANOVA) for the effects of age, sex, and diet on each of 72 variables. Twenty-eight variables were found to be influenced by age. By examining patterns of differences among means, 20 variables were identified that show promise of being useful, including, for example, rectal body temperature, blood albumin, immunoglobulin A, fingernail growth rate, bone thickness, and blood calcium. The set of variables used to estimate biological aging might not be identical for all age-sex classes.

Aging↗