Barry G. England

Social economics of childhood glucocorticoid stress response and health

This study examines socioeconomic conditions, psychosocial stress, and health among 264 infants, children, adolescents, and young adults aged 2 months to 18 years residing in a rural Caribbean village. Fieldwork was conducted over a 9 year period (1988-1996). Research methods and techniques include salivary cortisol radioimmunoassay (N = 22,438), systematic behavioral observations, psychological questionnaires, health evaluations, medical records, informal interviews, and participant observation. Analyses of data indicate complex relations among socioeconomic conditions, stress, and health. Household income, land ownership, parental education, and other socioeconomic measures are weakly associated with child illness. There is no evidence that apparent material benefits of high socioeconomic status--such as improved housing, diet, work loads, and access to private healthcare--have important direct effects on child health in this population. However, social relationships, especially family environment, may have important effects on childhood psychosocial stress and illness. Abnormal glucocorticoid response profiles, diminished immunity, and frequent illness are associated with unstable mating relationships for parents/caretakers and household composition. We suggest that family relationships and concomitant stress and immunosuppression are important intermediary links between socioeconomic conditions and child health.

A specific, non-chromatographic radioimmunoassay for human plasma cortisol

A radioimmunoassay technique has been developed for the measurement of cortisol in a single methylene chloride extract of human plasma without chromatography. The antiserum, obtained by immunizing rabbits with cortisol-3-carboxymethyl-oxime conjugated to bovine serum albumin, had a high affinity (KA = 1.8 X 10(9) 1/mole) and capacity (2.3 X 10(-6) moles/L undiluted serum) for cortisol. The minimum detectable amount determined at the lower 95% confidence limit of the buffer control tubes was 8.3 +/- 4.7 pg/tube and a log dose - logit response standard curve was linear between 20 pg and 20 ng/tube. The antiserum was highly specific for cortisol with only corticosterone, cortisone, 11-deoxycortisol and 21-deoxycortisol showing significant cross-reaction (12.4, 6.6, 3.8 and 3.7%, respectively). The cross-reaction for the other tested naturally occurring and synthetic steroids did not exceed 1%. Regression analysis of cortisol concentration estimates obtained on 20 samples before and after Sephadex LH-20 column chromatography gave a coefficient of correlation (r) of 0.995 and a regression coefficient (b) of 1.04. Recovery of cortisol added to plasma samples was quantitative. The intra-assay error was 8.5% and the inter-assay error averaged 5.7%. The method is simple requiring a single solvent extraction of plasma, therefore permitting large numbers of samples to be handled efficiently by a single technician.

Male-female differences in effects of parental absence on glucocorticoid stress response.

This study examines the family environments and hormone profiles of 316 individuals aged 2 months-58 years residing in a rural village on the east coast of Dominica, a former British colony in the West Indies. Fieldwork was conducted over an eight-year period (1988–1995). Research methods and techniques include radioimmunoassay of cortisol and testosterone from saliva samples (N=22,340), residence histories, behavioral observations of family interactions, extensive ethnographic interview and participant observation, psychological questionnaires, and medical examinations.Analyses of data indicate complex, sex-specific effects of family environment on endocrine function. Male endocrine profiles exhibit greater sensitivity to presence of father than do female endocrine profiles. Father-absent males tend to have (a) low cortisol levels during infancy, (b) high or abnormal cortisol profiles during childhood and adolescence, and (c) high cortisol and low testosterone levels during adulthood compared with those of males raised with a resident father. These results indicate that early family environment has significant effects on endocrine response throughout male life histories.

Hormonal response to competition among male coalitions

Previous research has shown that testosterone (T) and cortisol (C) are released in response to a wide variety of social stimuli including dyadic (one on one) competitive events, but humans also compete as groups. Here we report results from a pilot study of hormonal responses to competition between male coalitions. Salivary T and C levels were assessed in adult males from a rural Caribbean village who competed at dominoes, as two-man teams, against (a) familiar men from their own village (within coalition), and (b) strangers from another village (between coalitions). Analyses indicate that both T and C levels were higher and responses more pronounced for between-village competition than for within-village competition, but we could not compare responses to victory and defeat in the betweenvillage case, since our subjects happened to win both such contests. Further studies of endocrine responses in the context of coalitional competition are warranted. D 2002 Elsevier Science Inc. All rights reserved.

Folliculogenesis in the bovine

Abstract During the follicular phase of the estrous cycle in the cow, there is a rapid turnover in large (ovulatory size) follicles with the ovulatory follicle being identifiable by size not more than 3 days prior to estrus. Characteristics of the ovulatory follicle have been described in terms of steroid production and, to a lesser extent, gonadotropin receptors. It remains yet to be determined which factors permit development of these characteristics rather than leading to the onset of atresia.

A chemical approach to solving bridging phenomena in steroid radioimmunoassays

Steroid radioimmunoassays (RIA) employ antibodies raised against a carrier protein-steroid conjugate. Individual antibodies may recognize the steroid, the protein or the chemical bridge used to join them together. Use of the same bridge in the tracer results in higher affinity binding of the tracer than the native ligand which in turn results in a loss of sensitivity and precision. We have greatly reduced bridge-binding in a RIA for androstenedione. Conjugates and radioiodinated labels were prepared with either an ester or either chemical bridge. By using an antibody and the corresponding label with the heterologous bridge very sensitive assays were obtained.

Is Cortisol Excretion Independent of Menstrual Cycle Day? A Longitudinal Evaluation of First Morning Urinary Specimens

Background Cortisol is frequently used as a marker of physiologic stress levels. Using cortisol for that purpose, however, requires a thorough understanding of its normal longitudinal variability. The current understanding of longitudinal variability of basal cortisol secretion in women is very limited. It is often assumed, for example, that basal cortisol profiles do not vary across the menstrual cycle. This is a critical assumption: if cortisol were to follow a time dependent pattern during the menstrual cycle, then ignoring this cyclic variation could lead to erroneous imputation of physiologic stress. Yet, the assumption that basal cortisol levels are stable across the menstrual cycle rests on partial and contradictory evidence. Here we conduct a thorough test of that assumption using data collected for up to a year from 25 women living in rural Guatemala. Methodology We apply a linear mixed model to describe longitudinal first morning urinary cortisol profiles, accounting for differences in both mean and standard deviation of cortisol among women. To that aim we evaluate the fit of two alternative models. The first model assumes that cortisol does not vary with menstrual cycle day. The second assumes that cortisol mean varies across the menstrual cycle. Menstrual cycles are aligned on ovulation day (day 0). Follicular days are assigned negative numbers and luteal days positive numbers. When we compared Models 1 and 2 restricting our analysis to days between −14 (follicular) and day 14 (luteal) then day of the menstrual cycle did not emerge as a predictor of urinary cortisol levels (p-value >0.05). Yet, when we extended our analyses beyond that central 28-day-period then day of the menstrual cycle become a statistically significant predictor of cortisol levels. Significance The observed trend suggests that studies including cycling women should account for day dependent variation in cortisol in cycles with long follicular and luteal phases.

Half-life determination of serum free prostate-specific antigen following radical retropubic prostatectomy

OBJECTIVES Prostate-specific antigen (PSA) continues to be the the most clinically useful tumor marker for prostate cancer. Recently, several molecular forms of PSA have been detected and characterized. These specific forms, including free PSA and PSA complexed to alpha 1-antichymotrypsin, can be measured and their proportions determined. In doing so, the sensitivity of PSA as a tumor marker can be maintained while the specificity is improved. In order to maximize the clinical utility of free PSA, the half-life and elimination kinetics of free PSA from the serum were determined. METHODS Twenty-five patients, ages 43-74 years (mean 60 years) with biopsy proven, organ-confined adenocarcinoma of the prostate who underwent anatomic radical retropubic prostatectomy, were identified. For each patient, venous blood samples were obtained preoperatively, and at 60-minute intervals beginning 1 hour after the prostate was removed. The specimens were handled and stored in a consistent fashion. Using the AxSYM immunoassay analyzer (Abbott Diagnostics, Abbott Park, IL), the serum free PSA values were determined and plotted as a function of time for each patient. From the 25 individual elimination curves that were generated, the half-life of serum free PSA was determined. RESULTS The mean half-life of serum free PSA was 110 minutes +/- 18.6 minutes (SD). Analysis of the individual and cumulative elimination curves indicates that the elimination of free PSA from the serum following radical prostatectomy follows a biphasic pattern. CONCLUSIONS Unlike PSA, which has a half life of 2-3 days, the half-life of serum free PSA is 110 minutes (1.83 hours). This short half-life may have significant implications for the use of percentage of free PSA as a clinically useful tool in distinguishing patients with early, curable prostate cancer from men with benign prostatic hyperplasia (BPH) only.

In vitro growth regulation of endometrial carcinoma cells by tamoxifen and medroxyprogesterone acetate

The growth inhibitory effects of medroxyprogesterone acetate (MPA) and tamoxifen (TAM) were tested on three long-established endometrial carcinoma cell lines (HEC-1, KLE, and RL95-2) and on UM-EC-1, a new endometrial carcinoma cell line established in our laboratory. MPA and TAM were used in growth experiments either alone, simultaneously, or sequentially. The MCF-7 breast cancer cell line was used as a control. None of the endometrial carcinoma cell lines showed significant sensitivity to 0.1-10 microM MPA. In contrast, 10 days exposure to 5 microM TAM induced 83 and 70% growth inhibition in HEC-1 and KLE cultures, whereas the growth of UM-EC-1 was inhibited by 99.7% and RL95-2 cultures by 100%. TAM-induced growth inhibition was reversible since all cell lines resumed logarithmic growth when TAM was removed from the culture medium. Addition of 17 beta-estradiol (E2) to the culture medium did not accelerate recovery, and reversal of TAM-induced growth inhibition was not seen when TAM and E2 were added simultaneously. This is consistent with our finding that, except for MCF-7, these cell lines did not show detectable estrogen receptor (ER) activity in assays performed at the time of these experiments. When treated sequentially with TAM and MPA, all cell lines resumed logarithmic growth when medium containing TAM was replaced with medium containing MPA. Simultaneous exposure to 5 microM MPA and 5 microM TAM resulted in a slight additive growth inhibitory effects only in KLE cultures. Our results show that MPA does not have growth inhibitory effects in these endometrial carcinoma cell cultures, whereas TAM exerts a potent inhibitory effect that is not reversed by estrogen and may thus be mediated through a mechanism different from blockade of ER. In vitro results with the UM-EC-1 cell line correlated with the clinical response of the cell line donor. Her disease progressed during postoperative MPA therapy, but subsequently she responded to TAM therapy.

The Delivery of Testosterone and Dihydrotestosterone by ALCAP Ceramic Implants in Rats

The objectives of this investigation were to evaluate the release of testosterone (T) and dihydrotestosterone (DHT) from nonimpregnated and polylactic acid (PLA) impregnated ALCAP ceramic reservoirs implanted in rats, and to study the effects of delivered androgens on the reproductive system of male rats. A total of 120 Sprague-Dawley albino male rats were distributed equally into three groups Two ALCAP capsules, one nonimpregnated and the other impregnated with PLA, were implanted into each rat in groups I and II. Capsules implanted into group I rats were loaded with a mixture of 20 mg T and 20 mg DHT. Group II rats were implanted with two empty capsules (sham group), and group III animals served as unimplanted controls. Eight rats from each group were euthanized at the end of 3, 6, 9, and 12 months following the implantation of the ceramics. No significant change in the weights of vital organs of rats was observed among any of the three different groups. Vas deferens and epididymal fluid were devoid of normal spermatozoa within 3 months of implanting the steroid-containing ceramics. Testicular weights decreased significantly in the rats implanted with ALCAP containing steroids and the seminiferous tubules became oligospermic after 1 month and azoospermic after 3 months. The data collected in this study suggest that (1) ALCAP ceramic capsules are capable of delivering T and DHT in combined form, and (2) T and DHT delivered by ALCAP capsules can be used effectively to regulate spermatogenesis in rats.