PubMed Health⌕ Search

Biomedical subjects

W Rowe

Publications and source records attributed to W Rowe.

At least 37 records · Page 2Linked to original sources
PubMed1992

Serotonergic regulation of type II corticosteroid receptor binding in hippocampal cell cultures: evidence for the importance of serotonin-induced changes in cAMP levels.

The development of the hypothalamic-pituitary-adrenal response to stress is profoundly altered by environmental events. One target for environmental regulation within the hypothalamic-pituitary-adrenal axis is the hippocampal type II corticosteroid (or glucocorticoid) receptor system, which mediates the negative-feedback effects of glucocorticoids on hypothalamic-pituitary-adrenal activity. Thus, adult rats handled early in life show increased hippocampal type II corticosteroid receptor density and increased sensitivity to the inhibitory effects of circulating glucocorticoids on post-stress hypothalamic-pituitary-adrenal activity. Both effects persist throughout life. The effects of handling on type II corticosteroid receptor development are, at least in part, mediated by changes in hippocampal 5-hydroxytryptamine turnover. Moreover, 5-hydroxytryptamine can regulate type II corticosteroid receptor density in cultured hippocampal cells, providing a paradigm for examining the neurochemical mechanisms by which environmental stimuli might regulate neural differentiation. In the present studies, we examined the intracellular mechanisms underlying the effects of 5-hydroxytryptamine on type II corticosteroid receptors ([3H]RU 28362 binding) in hippocampal cell cultures. cAMP, but not cGMP, levels in cultured hippocampal cells were significantly increased by the addition of 5-hydroxytryptamine to the medium. The cAMP response to 5-hydroxytryptamine was biphasic: an initial increase in cAMP levels occurred in response to nanomolar 5-hydroxytryptamine concentrations (EC50 = 7.2 nM), while a second increase was apparent at low micromolar concentrations. 5-Hydroxytryptamine also increased [3H]RU 28362 binding (EC50 = 4.5 nM) with a maximal effect at a concentration of 10 nM. There was no further increase in [3H]RU 28362 binding even with higher, micromolar concentrations of 5-hydroxytryptamine.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1992

Scanning electron microscopic study of primary teeth in X-linked amelogenesis imperfecta.

Exfoliated primary teeth from a boy and a girl from a family with X-linked amelogenesis imperfecta (XAI) were studied by scanning electron microscopy. Teeth from the boy featured multiple shallow depressions on the enamel surface interspersed with deeper tubular voids. Shallow depressions and similar tubular defects were also apparent in control teeth from an unaffected individual but these were less frequent, irregularly distributed and less marked. Teeth from the heterozygous girl had broad furrows running longitudinally from the cusp(s) of the tooth cervically. These furrows were formed by a series of saucerized depressions which merged together in some areas. The bases of these depressions featured tubular voids extending into the enamel. These similar voids in teeth from both boy and girl probably represent enamel prism spaces vacant because of defective enamel protein synthesis and/or mineralization. Although the scanning electron microscopic features of teeth from females observed in this and previous studies of XAI differ, the enamel appears to be more similar in males with differing clinical XAI phenotypes.

Amelogenesis Imperfecta↗
PubMed1992

Purchase considerations for a radiology information system.

Since choosing a radiology information system can be a trying endeavor, this "nuts and bolts" article offers some practical advice. The authors first emphasize that a strong partnership between the institution and vendor must exist for successful implementation to happen. Ms. Rowe and Ms. Parrish then proceed to outline the commitment, tasks and training necessary to ensure that your organization undertakes this project with favorable results!

Computer User Training↗
PubMed1990

Hypothalamic-pituitary-adrenal activity in aged, cognitively impaired and cognitively unimpaired rats.

There is a tendency for increased hypothalamic-pituitary-adrenal (HPA) activity with age in the rat, and the resulting elevations in circulating glucocorticoid levels have been implicated in the occurrence of hippocampal pathology and memory deficits. In the experiments reported here, we examined whether HPA dysfunction is selectively associated with cognitive impairments in a population of aged rats. Fifty-eight 23-27-month-old male Long-Evans rats were screened for spatial memory impairments using the Morris swim maze, and 2 groups of aged animals were selected; aged, cognitively impaired (AI) animals whose performance was significantly different (greater than 2 SD) from that of 6-month-old controls and aged, cognitively unimpaired (AU) animals whose performance was comparable to that of the young controls (a difference of less than 0.5 SD). Twenty-eight percent of the animals tested were designated as AI and 20% as AU. Histological analysis of a subset of these animals showed that, while both AU and AI animals showed neuron loss in the pyramidal cell fields of the hippocampus, the loss was significantly greater in the AI animals. The AI animals showed clear evidence of increased HPA activity. Thus, basal ACTH and corticosterone levels were significantly higher in the AI animals compared with both AU animals and young controls, especially during the dark phase of the cycle. The AI, AU, and young animals exhibited comparable corticosterone levels during a 20-min immobilization stress; however, following the termination of the stressor, corticosterone levels in AI animals were significantly elevated compared with both AU animals and controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1990

Serotonin regulates type II corticosteroid receptor binding in hippocampal cell cultures.

Previous work from our laboratory has shown that early postnatal handling of rat pups permanently increases hippocampal type II, but not type I, corticosteroid receptor binding. Handling also increases hippocampal 5-HT turnover, and the effect of handling on type II corticosteroid receptor binding is blocked by concurrent administration of the 5-HT2 receptor antagonist ketanserin. In view of these findings, the present studies examined the effects of 5-HT on type I ([3H]corticosterone) and type II ([3H]RU 28362) corticosteroid receptor binding in dispersed hippocampal cell cultures derived from animals killed at E19-20 in order to verify that 5-HT can act directly on hippocampal cells to alter corticosteroid receptor binding. Both type I and type II receptors were measurable in cultured hippocampal cells and the apparent affinity (Kd) for [3H]corticosterone (0.4 +/- 0.1 nM) and [3H]RU 28362 (0.8 +/- 0.1 nM) was similar to that from studies with intact animals. 5-HT increased type II, but not type I, corticosteroid receptor binding capacity in a dose-related manner, with the maximal effect (+188%) observed at 10 nM 5-HT and no change in the affinity of the receptor for [3H]RU 28362. The effect of 10 nM 5-HT on [3H]RU 28362 binding required a minimum of 4 d exposure and persisted for at least 7 d following the removal of 5-HT. The effect of 10 nM 5-HT on [3H]RU 28362 binding was completely blocked by the 5-HT2 receptor antagonists ketanserin and mianserin. There were no effects of the 5-HT1a antagonist, BMY 7378, or the 5-HT3 antagonist, MDL 72222.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Linkage of the Igl-1 structural and regulatory genes to Akv-2 on chromosome 16.

Evidence is presented here for a close linkage between Akv-2, an ecotropic provirus found uniquely on chromosome 16 of AKR/N mice, and the immunoglobulin lambda 1 light chain locus, Igl-1. No recombinants between the Igl-1 locus and Akv-2 were found by Southern blot analysis of DNA obtained from progeny of the backcross of (AKR/N X SJL/J)F1 to SJL/J, indicating that these genes map within 5.9 cM of each other. A probe specific for the flanking sequence of Akv-2 was used to detect the provirus, while one specific for the Igl-1 constant region was used to determine which allele of the structural gene was expressed in the backcross mice. The constant region of Igl-1 differs between AKR/N and SJL/J with respect to a site for the restriction endonuclease KpnI. This backcross was also used to seek recombinants between the regulatory, Igl-1r, and structural, Igl-1, loci of the immunoglobulin light chain locus, since the existence of such recombinants would prove that these loci are distinct. Since only parental types were recovered in the offspring, the structural and regulatory loci are no more than 2.3 cM apart, and the implications of this finding are discussed.

Animals↗
PubMed1983

Cold pressor test in diagnosis of coronary artery disease: echophonocardiographic method.

The cold pressor test was used to induce myocardial ischaemia in patients with coronary artery disease and the rise in left ventricular filling pressure used as the index of myocardial ischaemia. Left ventricular filling pressure was derived from a non-invasive echophonocardiographic method. A study group of 19 consecutive patients with chest pain underwent the cold pressor test before coronary angiography. Eighteen responded with a rise in filling pressure exceeding 30% and, of these, 17 had serious coronary artery disease (three single vessel, one two vessel, and 13 triple vessel disease; one had coronary artery spasm only). The remaining patient, who showed no rise in filling pressure, did not have coronary artery disease. None of 15 normal controls showed a rise greater than 5% (patients with coronary artery disease versus normal controls p less than 0.001). The cold pressor test would be suitable for patients who cannot or should not exercise and may be combined with exercise electrocardiograms to improve the information content, as it uses a different marker of myocardial ischaemia.

Adolescent↗
PubMed1978

Taped vs. "live" desensitization and level of autonomic arousal.

Investigated whether variations in method of presentation of anxiety items (Es voice, E's taped voice, S's taped voice) will result in differences in autonomic arousal (as measured by self-report, galvanic skin responses, cardiac rate, blood pressure). Ss were 24 Naval Academy midshipmen. The procedure involved (1) training in deep muscle relaxation; and (2) measuring arousal after the presentation of anxiety-eliciting stimuli. Statistical analysis indicated that the influence of method of presentation was significant for galvanic skin response and self-reported anxiety. Comparison of cell means showed that verbal presentations were more effective in eliciting autonomic arousal than taped presentations. The results of this study provide partial evidence to support the conventional form of systematic desensitization as more effective than the newer automated or taped versions.

Anxiety↗
PubMedDate not supplied

Individual differences in hypothalamic-pituitary-adrenal activity in later life and hippocampal aging.

Variation in magnitude of cognitive decline in later life is a central feature of human aging. The more severe forms of dementias, such as Alzheimer's disease, clearly define one end of the spectrum. However, among those showing no obvious signs of clinical dementia there are considerable individual differences. Thus, although evidence for learning, memory, and language loss appears in some individuals as early as 50-55 years of age, many people continue to function alertly well into their 90s. These individuals exemplify what Rowe and Kahn (1987) have termed "successful" aging. The wide variability in CNS aging, often a nuisance factor in studies, are becoming a major focus for brain aging research (e.g., Gage et al., 1984;Gallager and Pelleymounter, 1988; Aitken and Meaney, 1990; Issa et al., 1990). Our studies over the past few years have added support to the idea that individual differences in hypothalamic-pituitary-adrenal (HPA) activity can account for part of the variation seen in neurological function among the elderly. In this article we discuss the evidence for the idea that adrenal glucocorticoids can compromise hippocampal function and, thus, produce cognitive impairments, as well as the potential mechanisms for these effects.

Aged↗
PubMedDate not supplied

Neurotrophin receptor and tyrosine hydroxylase gene expression in aged sympathetic neurons.

Ribonuclease protection measurements revealed decreases of 26% in p75 neurotrophin receptor mRNA and 30% in trkA mRNA in superior cervical ganglia (SCG) of aged Long-Evans rats. These declines were not related to the presence of a spatial memory impairment, whose presence is known to strongly predict increased hypothalamic-pituitary-adrenal axis activity in these aged animals. A similar decrease with age was observed in p75, but not cyclophilin mRNA levels in SCG from F-344 inbred rats. In situ hybridization with paired sections from mature and aged F-344 rats revealed a 25% decline in the mean neuronal labeling index (LI) for p75 mRNA. In other paired sections, mean trkA LI decreased 16%, tyrosine hydroxylase (TH) LI increased 74% and cyclophilin LI did not change. Neuronal hypertrophy, p75 decreases and TH increases all occurred to a greatest extent in intermediate-sized neurons, resembling those innervating the pineal and cerebral vessels. In contrast to other SCG targets, this innervation is known to decline nearly 50% with aging. Retrograde tracer/in situ hybridization studies will be required to establish whether decreased p75 represents a marker for selective axonal regression and also to determine the significance of increased TH and neuronal hypertrophy.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Antidepressants restore hypothalamic-pituitary-adrenal feedback function in aged, cognitively-impaired rats.

Aged, cognitively-impaired rats (and humans) show hypothalamic-pituitary-adrenal (HPA) hyperactivity that correlates with hippocampal damage. The resultant increase in plasma glucocorticoid exposure is thought to contribute to impaired hippocampal function and to potentiate hippocampal neuron death. In young, adult rats antidepressant drugs increase corticosteroid receptor expression in brain regions known to regulate the HPA axis, leading to increased negative-feedback control and decreased HPA activity. In the present study we examined basal levels of plasma adrenocorticotropin hormone (ACTH) and corticosterone in aged, cognitively-impaired (AI), aged, cognitively-unimpaired (AU) and young, adult (Yg) rats. Plasma ACTH and corticosterone levels were significantly elevated in the AI rats, but only in samples obtained during the diurnal peak. Five weeks of treatment with desipramine (15 mg/kg) significantly reduced evening levels of both ACTH and corticosterone in all groups, and eliminated the group differences. We then examined delayed, glucocorticoid negative feedback in these animals. Among vehicle-treated animals, a bolus injection of corticosterone (10 mg/kg), administered 3 hours prior to testing, completely inhibited the plasma ACTH response to restraint in AU and Yg, but not AI animals. In contrast, plasma ACTH responses to restraint were completely inhibited in AI rats following chronic treatment with desipramine. These findings indicate that the antidepressant, desipramine, decreases HPA activity and increases glucocorticoid negative-feedback sensitivity in AI rats, suggesting that antidepressant drugs may form a useful therapeutic approach to HPA dysfunction in elderly human populations.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Effect of altered duration of 41.5 degrees C whole body hyperthermia in combination with cis-diamminedichloroplatinum (II) on tumor and normal tissue apoptosis and tumor response in rats.

We investigated the correlation between antitumor efficacy and kinetics of tumor and normal tissue apoptosis when cis-diamminedichloroplatinum (II) (CDDP) was combined with two different durations of whole body hyperthermia [SH-WBH, at 41.5 degrees C for 1 h (1 h WBH) or 2 h (2 h WBH)]. Rats bearing a mammary adenocarcinoma (MTLn3) were treated with 1 or 2 h WBH CDDP and then assessed for tumor growth delay (TGD). A separate study examined the amount of induced apoptosis in tumor and normal tissue (thymus and ileum) over 96 h following the same treatments. 1 h WBH + CDDP increased the TGD to 10.5+/-0.5 days, which was not statistically different from the TGD of 12.3+/-0.5 days obtained with 2 h WBH + CDDP. The area under the curve (AUC) of percentage tumor apoptosis for 1 h WBH + CDDP was 50% of that of 2 h WBH + CDDP. The AUC of percentage thymus apoptosis for 1 h WBH + CDDP was 25% of that of 2 h WBH + CDDP, and the AUC of the score of ileal apoptosis for 1 h WBH + CDDP was 81% of that of 2 h WBH + CDDP. These data indicate that while 1 h WBH + CDDP induced less tumor apoptosis than 2 h WBH + CDDP, antitumor activity was enhanced to a similar degree by both 1 h and 2 h WBH + CDDP, and since 1 h WBH + CDDP caused less normal tissue apoptosis than 2 h WBH + CDDP, a 1 h duration of WBH + CDDP may be a therapy that is both, as effective as, and safer than a 2 h duration of WBH + CDDP.

Adenocarcinoma↗