Biomedical subjects
Publications and source records attributed to B J Davidson.
The problem of lymphadenopathy in HIV-seropositive patients is reviewed, and indications for further study are presented. Implications for patients who later develop AIDS are discussed.
Estrogens are known to increase the renin-angiotensin-aldosterone system and to produce fluid retention, while atrial natriuretic peptide (ANP) induces an increase of the urinary output and tends to return the fluid balance to normal. The aim of this study was to test whether the levels of ANP were decreased during chronic estrogen and progestin administration, thereby possibly decreasing the amount of fluid excreted. The authors also studied women with premenstrual syndrome (PMS), because of the associated fluid retention often described with this syndrome. Levels of ANP, plasma renin activity (PRA), and aldosterone were determined in premenopausal women in the early follicular phase (EFP) and on low-dose oral contraceptives (OC), in postmenopausal patients with and without estrogen replacement therapy (ERT), and in women with PMS associated with fluid retention. The concentrations of ANP and PRA were enhanced in the women on OC, but those of aldosterone were unchanged. No differences were observed in the women on ERT or with PMS. It is concluded that the levels of PRA and ANP are affected by estrogen or progesterone therapy or the combination of the two and this response is dose dependent or additive. Furthermore, ANP and PRA do not seem to play a direct role in PMS.
Before or during labor in humans, changes in peripheral levels of estrogen and progesterone are not evident. Local alterations of estrogen, progesterone, and prolactin concentrations may be present and be accompanied by prostaglandin changes. The purpose of this study was to investigate the differences in concentrations of these hormones across the uterus and to evaluate their interrelationships in patients at term gestation with and without labor. Blood samples were obtained from a radial artery and a uterine vein in 22 women without and in 10 with labor. The difference between levels in the two blood vessels was designated as the gradient. Neither levels nor gradients were different between the two groups for estrone, estradiol, estriol, progesterone, or prolactin. The plasma levels of prostaglandin F2 alpha, 13,14-dihydro-15-keto-prostaglandin F2 alpha, and prostaglandin E2 were significantly increased in labor. Prostacyclin levels, as indicated by the 6-keto-prostaglandin F1 alpha metabolite, were not altered. The gradients for prostaglandin F2 alpha and E2 were significantly increased in labor. The results of the study also suggested that, in gestation at term, serum prolactin is produced mainly by the pituitary and that estrone may originate from peripheral conversion of estradiol. We conclude that in humans prostaglandin gradients of the E and F groups are increased in labor. These increases are not associated with changes in sex steroids or prolactin. Prostacyclin metabolite gradients also appear not to be altered in labor, suggesting that some prostaglandins are selectively increased in early labor either by enhanced production or decreased metabolism or both.
The authors evaluated 774 endometrial biopsies that were performed for infertility. Complications arose in 3.6%. Lag of more than 2 days was found in 19%; luteal phase defect (LPD) was diagnosed in 5.7%. Most of the incidence of LPD can be predicted from chance occurrence. There was no association between abnormal biopsies and basal body temperature patterns, or between pathology, pregnancy outcome, and treatment. Exceptions included women with multiple spontaneous abortions and patients treated with clomiphene citrate (CC). An endometrial biopsy was performed in a pregnancy cycle in 4.0%, with an abortion rate not significantly different from the total study group. The authors conclude that an endometrial biopsy is relatively safe; however, the diagnostic and therapeutic consequences are limited. Endometrial biopsies may be useful only if performed in cases of habitual abortion or ovulation induction with CC.
Ritodrine hydrochloride, a beta-sympathomimetic treatment for premature labor, has been associated with the development of pulmonary edema, various metabolic derangements, myocardial ischemia, and infarction. We present the first reported case of absolute neutropenia after prolonged intravenous administration of ritodrine with rapid, spontaneous reversal once the medication was discontinued.
Three experiments used a new paradigm to examine word-coding processes during reading. Subjects read text passages and occasionally responded to lexical-decision probes. Experiment 1 focused on semantic and surface codes. The activation of semantic codes appeared to increase over time, whereas surface codes did not. In addition, subjects who were instructed to remember the exact wording of the passages showed stronger activation of surface codes than did subjects who read for comprehension. Experiments 2 and 3 explored the role of phonological codes. Experiment 2 showed that phonological codes were activated by specific words in a passage. In contrast, Experiment 3 found no evidence that phonological codes were activated by the more general passage context. Taken together, the experiments suggest some of the roles semantic and phonological codes may play during reading.
There is no simple and rapid test available to predict the outcome of an early pregnancy complicated by vaginal bleeding. In this prospective study, 15 women with normal pregnancies collected a weekly urine sample between 6 and 13 weeks' gestation. A single random urine sample was obtained from 15 women with bleeding who continued to carry their child and 50 women who proceeded to have a spontaneous abortion (SAB). Pregnandiol-3-glucuronide (PDG) was determined with the use of enzyme-multiplied immunoassay technique (EMIT) and estrone conjugates (E1C) were measured by radioimmunoassay (RIA). The ratios of these metabolites to creatinine (C) were calculated. PDG/C ratios in normal women rose gradually from 6 weeks on. All women with bleeding during a normal pregnancy had ratios in the normal range, but 94% of women with a SAB had ratios below the normal range. The E1C/C ratio remained unchanged from 6 to 11 weeks and then rose rapidly. Until 11 weeks, there was no clear separation between the E1C/C ratios of the women with a SAB and the women with bleeding who continued their pregnancies. The prognosis of threatened abortion can be made by a urinary PDG/C ratio but not by an E1C/C ratio. EMIT is simple and quick and uses technology present in many laboratories.
Eight volunteer post partum female patients were examined with high resolution computed tomography during the week immediately after delivery. All patients received high dose (40-70 gm) intravenous iodine contrast administration. The scans were examined for pituitary gland height, shape and homogeneity. All of the patients had enlarged glands by the traditional standards (i.e. gland height of 8 mm or greater). The diaphragma sellae in every case bulged upward with a convex domed appearance. The glands were generally inhomogeneous. One gland had a 4 mm focal well defined area of decreased attenuation. Two patients who were studied again months later had glands which had returned to "normal" size. The enlarged, upwardly convex pituitary gland appears to be typical and normal for the recently post partum period.
The development of phonetic codes in memory of 141 pairs of normal and disabled readers from 7.8 to 16.8 years of age was tested with a task adapted from L. S. Mark, D. Shankweiler, I. Y. Liberman, and C. A. Fowler (Memory & Cognition, 1977, 5, 623-629) that measured false-positive errors in recognition memory for foil words which rhymed with words in the memory list versus foil words that did not rhyme. Our younger subjects replicated Mark et al., showing a larger difference between rhyming and nonrhyming false-positive errors for the normal readers. The older disabled readers' phonetic effect was comparable to that of the younger normal readers, suggesting a developmental lag in their use of phonetic coding in memory. Surprisingly, the normal readers' phonetic effect declined with age in the recognition task, but they maintained a significant advantage across age in the auditory WISC-R digit span recall test, and a test of phonological nonword decoding. The normals' decline with age in rhyming confusion may be due to an increase in the precision of their phonetic codes.
The inhalation, by grain elevator workers, of airborne grain dusts can lead to pulmonary problems. Complement, which is present in human airways, can interact with various grain dusts, producing activation products that have been shown to participate in the inflammatory reaction. Because of this apparent connection between grain-dust inhalation, complement activation, and respiratory difficulties, we are studying the reaction of an aqueous extract of spring wheat dust (swd) with human complement. The swd extract activates both the classical and alternative pathways; it acts on purified C2 to inhibit it, and it reacts with undiluted serum to consume C4 with kinetics significantly different from those shown by a "typical" antigen-antibody complex (sensitized sheep erythrocytes). Enzyme susceptibility experiments suggest that the alternative and classical pathway activators of swd extract are neither protein nor nucleic acid; periodate oxidation indicates these substances are carbohydrate, and gel filtration suggests they are macromolecular. Enzyme vulnerability also indicates that the C2 inhibitor of swd extract is ribonucleic acid. Although endotoxin is present in swd extract, a gel-filtration experiment showed that a major fraction of the complement reactivity was not associated with this substance.
Comparisons were made of the physical characteristics and the sex hormone levels of 50 postmenopausal women, half of whom had sustained an osteoporotic hip fracture while the remainder had developed endometrial carcinoma. None of the patients had received estrogen replacement therapy for longer than 3 months during their lifetime. At the time of injury hip fracture patients were found to be lighter (121 +/- 5 versus 167 +/- 9 pounds) and older (73.4 +/- 1.0 versus 62.6 +/- 1.7 years) than the cancer patients at the time of diagnosis. Estrone, estradiol, percentage of free estradiol, and free estradiol levels were significantly lower in the hip fracture patients than in subjects with endometrial cancer, while sex hormone-binding globulin levels were significantly higher in the former group. Androstenedione and testosterone levels were similar. Previous studies have shown that the incidence of both lesions is influenced by body size. These data suggest that body size may exert this influence through alteration of endogenous estrogen metabolism with hip fracture patients having lower concentrations and endometrial cancer patients having higher concentrations of endogenous estrogens.
Dyslexic and normal readers' eye movements were compared while tracking a moving fixation point and in reading. Contrary to previous reports, the dyslexic and normal readers did not differ in their number of saccades, percentage of regressions, or stability of fixations in the tracking task. Thus, defective oculomotor control was not associated with or a causal factor in dyslexia, and the dyslexics' abnormal eye movements in reading must be related to differences in higher cognitive processes. However, individual differences in oculmotor efficiency, independent of reading ability, were found within both the dyslexic and normal groups, and these differences were correlated in reading and tracking tasks.
Vertebral fractures due to osteoporosis commonly occur in postmenopausal women. Levels of cortisol and sex steroids in the circulation vary among older women. It has been suggested that this variation may contribute to the occurrence of osteoporotic fractures in some subjects but not others. To examine this, 30 patients with osteoporotic spinal fractures were compared to an equal number of controls matched to the patients for age and years since menopause. All subjects had intact ovaries and had not taken estrogen replacement therapy for more than 3 months during their entire lifetime. Spinal bone mineral density determined by dual photon absorptiometry was significantly lower (P less than .01) in the fraction group (0.75 +/- 0.03 g/cm2) than in the controls (1.0 +/- 0.03 g/cm2). No significant differences in body habitus or cortisol and sex steroid levels (both total and free) were found, with the exception of total estradiol levels, which were 16% higher in the fracture patients. This difference was presumably coincidental as there was no difference of free estradiol levels between groups. It is concluded that factors other than the differences of endogenous cortisol and sex steroid levels present in these postmenopausal women were responsible for the reduced bone mineral density of the spine observed in the fracture patients.
The circadian rhythm of prolactin secretion was assessed in postmenopausal women before and after daily administration of ethinyl estradiol for 4 weeks given in the morning (AM) or evening (PM) or in combination with a synthetic progestin, 17-medroxyprogesterone acetate. In response to AM ethinyl estradiol, mean circulating levels of serum prolactin during sleep and awake phases of the day rose 2.5-fold compared to untreated control values. The sleep/wake ratios for serum prolactin were comparable prior to and after AM administration of ethinyl estradiol. Altered time of administration, PM ethinyl estradiol or concomitant ethinyl estradiol and progestin treatment produced similar increases in mean prolactin levels, which were not different from the level observed during AM administration of ethinyl estradiol. These findings indicate that estrogen replacement therapy, in a dosage recommended for treatment of the menopause, stimulated a sustained rise in serum prolactin over 24 hours. This enhanced release of prolactin was not influenced by the time of administration of estrogen or concomitant administration of 17-medroxyprogesterone acetate.
Hip fracture constitutes the most serious complication of postmenopausal osteoporosis. To examine the possible role of circulating estrogen or androgen levels in the development of this type of fracture, 25 patients with hip fractures after minimal trauma were compared to an equal number of controls, matched for age and years since menopause. All were from a retirement community, had intact ovaries, and had not taken estrogen replacement for longer than 3 months during their entire lifetime. Hip fracture patients were found to have a significantly lower (P = 0.031) mean (+/-SE) percent ideal weight (89.4 +/- 2.9%) than controls (100.0 +/- 2.5%). Sex hormone-binding globulin levels were significantly higher (P = 0.004) in patients (6.7 +/- 0.4 X 10-8 M) than in controls (4.9 +/- 0.3 X 10-8 M), resulting in lower concentrations of biologically available estradiol and testosterone. In a subgroup of 12 patients and controls matched for percent ideal weight, differences in sex hormone binding globulin and free testosterone and estradiol levels were no longer statistically significant; however, the difference in the percentage of free testosterone persisted. These data suggest that endogenous sex steroids in their unbound form may play a role in the pathogenesis of postmenopausal hip fractures. The differences in free hormone levels appeared to be influenced by the differences in mean body size of the 2 groups. This factor is known to have an important negative effect on the concentration of sex hormone-binding globulin.
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To assess the role of biologically active estradiol in the development of endometrial cancer, 25 patients with endometrial tumors and a similar number of control subjects matched for age and body size were studied. No differences between the 2 groups were found for levels of total estradiol, sex hormone-binding globulin (SHBG), non-SHBG-bound estradiol, and absolute free estradiol. Body size correlated positively with levels of total, non-SHBG-bound, and absolute estradiol and negatively with SHBG levels. The obese postmenopausal women had higher total circulating levels and proportionally greater concentrations of free estradiol than nonobese subjects, suggesting a dual risk for the cellular action of circulating estradiol. These factors could contribute to the association of obesity and the occurrence of this tumor in susceptible women.