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Biomedical subjects

R Day

Publications and source records attributed to R Day.

At least 217 records · Page 12Linked to original sources
PubMed1989

Chronic electroconvulsive shock treatment elicits up-regulation of CRF and AVP mRNA in select populations of neuroendocrine neurons.

The effects of repeated electroconvulsive seizures (ECS) on expression of mRNAs coding for corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) in neuroendocrine neurons of the hypothalamo-pituitary-adrenocortical (HPA) axis and hypothalamo-neurohypophysial system (HNS) were assessed via semi-quantitative in situ hybridization histochemical analysis. Measures of mRNA content were accompanied by measurement of peptide- and hormone-expression in the relevant neuroendocrine systems. Following 7 daily ECS treatments, CRF mRNA was significantly increased in the medial parvocellular paraventricular nucleus (PVN) of treated rats relative to controls. CRF peptide content of whole PVN homogenates was decreased to 50% of control levels. Changes in CRF message and peptide levels were accompanied by increases in pituitary ACTH content and by elevated plasma corticosterone, suggesting ECS elicits long-term up-regulation of the HPA axis. AVP mRNA in the medial parvocellular PVN, which is known to up-regulate in response to HPA challenge by adrenalectomy, was not increased by ECS. Chronic ECS causes a clear up-regulation of HNS neurons of the supraoptic nucleus, characterized by increased AVP mRNA content, decreased AVP peptide content, and depletion of neurohypophysial AVP. However, no changes were observed in magnocellular vasopressinergic neurons of the PVN, indicating that magnocellular SON and PVN neurons respond differentially to stimulation by ECS. The data indicate that ECS is a potent stimulus for activation of select components of both the HPA axis and the HNS. As such, ECS provides a useful tool for examining mechanisms underlying neuroendocrine processes.

Animals↗
PubMed1989

Detection of a 15q deletion in a child with Angelman syndrome by cytogenetic analysis and flow cytometry.

A proximal 15q deletion, del(15) (q11:q13), was detected in a child with Angelman syndrome by cytogenetic analysis of peripheral lymphocytes. The chromosomes of both parents appeared normal. Flow karyotype analysis carried out on lymphoblastoid cell lines derived from the child and her parents confirmed the presence of a de novo 15 deletion. The estimated size of the deleted segment ranged from 6.1-9.5% of chromosome 15 (approximately 6-9.3 million base pairs). The parental origin of the deleted chromosome could not be resolved by flow cytometry, but cytogenetic evidence suggested that it was derived from the smaller chromosome 15 homologue in the mother.

Abnormalities, Multiple↗
PubMed1989

Lack of interaction between sulindac or naproxen and propranolol in hypertensive patients.

Seventeen patients with hypertension and osteoarthritis participated in a single-blind crossover study comparing the effects of sulindac 200 mg twice daily, naproxen 500 mg twice daily, and placebo on blood pressure. All patients were treated for hypertension with propranolol monotherapy. Blood pressures were back-titrated to achieve a baseline diastolic blood pressure of 90 to 100 mm Hg while taking naproxen. There were no significant differences in mean sitting or standing blood pressures among the patients receiving naproxen, sulindac, or placebo treatments. There was no change in pulse, weight, or any of the laboratory measurements at the end of each treatment phase. These results suggest that neither sulindac nor naproxen interferes with propranolol therapy for uncomplicated hypertension.

Blood Pressure↗
PubMed1989

An investigation of a reported cancer cluster in Randolph, Massachusetts.

An increasingly common public health problem is the perception that disease incidence has increased or a cluster of disease has occurred in a community. In most cases, the disease of concern is cancer and a local hazardous waste site or other environmental problem is involved. These problems can be difficult to investigate and public health officials are frequently criticized for their inability to address community concerns. This paper reports a case study of such a situation occurring in the Barlett-Green Acres (BGA) neighborhood of Randolph, Massachusetts. Study data were obtained by interviews in households of persons belonging to a list of alleged cancer cases initially supplied by residents and supplemented using records available in town and state public health offices. One objective of the investigation was to develop methods that may be of value in similar situations arising in other communities. From a list of names compiled prior to and during the investigation, 45 incident cases of cancer were identified and found suitable for analysis. An additional four cases were added from the Massachusetts Cancer Registry. The analysis showed the existence of a cancer cluster, but overall cancer incidence and mortality in the BGA neighborhood were not elevated. Residence history, disease site, and other features of the cancer cases were investigated using methods less sensitive to incomplete reporting than total incidence. No unusual features of the cancer data other than the initiating cluster were identified and no environmental hazard likely to impact the BGA neighborhood was discovered, hence we conclude that the most likely cause of the cancer cluster was random variation in cancer rates.

Adolescent↗
PubMed1989

The posttranslational processing of prodynorphin in the rat anterior pituitary.

The posttranslational processing of prodynorphin (Pro-Dyn) is not well understood. The rat anterior pituitary is an interesting tissue which merits examination to address this issue since it is known that Dyn immunoreactivity is stored as high mol wt (HMW) intermediates and not as free products such as dynorphin-A-(1-17) (Dyn-A17) or dynorphin-B-(1-13) (Dyn-B). The aim of our study is to characterize the Pro-Dyn products in the rat anterior pituitary quantitatively as well as qualitatively by keeping a close account of each of the possible domains that are known to compose the protein structure. This was achieved by a convergence of tools: designing RIA with antibodies to each of these domains, including antibodies to Dyn-A17, Dyn-B, alpha-neo-endorphin, bridge peptide, and Pro-Dyn carboxyl-terminal peptide (C-peptide), and using these antisera with gel filtration chromatography, reverse phase HPLC, immunoaffinity, and immunoprecipitation techniques. Our data indicate the presence of at least six distinct molecules which are classified as HMW intermediates (greater than 3.5K). By gel filtration chromatography they have apparent mol wt of 16,000, 10,000, 8,000, 6,000, 4,000, and 3,500, respectively. Each of these structures is characterized by multiple immunoreactivities to account for the observed mass. Based on the relative content of each structure we present a scheme for the posttranslational processing pathway of Pro-Dyn in the rat anterior pituitary. We also analyze other tissues, spinal cord and hypothalamus, for their content of Pro-Dyn HMW intermediates. Our results indicate that these tissues store Pro-Dyn HMW molecules of similar sizes and immunoreactive properties, suggesting that Pro-Dyn may be processed in a similar manner, at least in the initial phases, across tissues.

Animals↗
PubMed1989

Time course of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and messenger ribonucleic acid, biliary lipid secretion, and hepatic cholesterol content in methimazole-treated hypothyroid and hypophysectomized rats after triiodothyronine administration: possible linkage of cholesterol synthesis to biliary secretion.

In an effort to define the mechanism by which thyroid hormone increases the synthesis of hepatic cholesterol, we have investigated both in hypophysectomized and methimazole-treated hypothyroid rats the time course of T3 effects on plasma cholesterol concentration, total hepatic cholesterol, the rate of biliary secretion of cholesterol, bile acids, and phospholipids, and the activity and mRNA levels of 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase, the rate-limiting enzyme in the hepatic synthesis of cholesterol. A single dose of 200 micrograms T3 was estimated to maintain at least 90% nuclear occupancy for the ensuing 54 h of the experiment. In both preparations the relative rise in biliary secretion of cholesterol exceeded that of other biliary constituents and preceded by 12 h an increase in HMG-CoA reductase enzyme activity and its mRNA. The level of total hepatic cholesterol remained constant throughout the experiment. We interpret these findings to suggest that T3-stimulated cholesterol synthesis is mediated by an antecedent T3-induced rise in biliary cholesterol secretion. We postulate that biliary cholesterol secretion is augmented by an intrahepatic shift of cholesterol and depletion of the hepatic sampling center responsible for the feedback regulation of cholesterol synthesis. The level of HMG CoA reductase mRNA appeared to govern enzyme activity in both preparations, but the ratio of mRNA to hepatic enzyme activity was substantially greater in the methimazole-treated compared with the hyphophysectomized animals.

Animals↗
PubMed1988

Regulation of hypothalamic magnocellular neuropeptides and their mRNAs in the Brattleboro rat: coordinate responses to further osmotic challenge.

A paradigm was developed for the chronic osmotic stimulation of homozygous diabetes insipidus rats of the Brattleboro strain, a strain that fails to synthesize vasopressin. This study examines the adaptation of 2 sets of coexisting peptide hormone magnocellular neurons in the hypothalamoneurohypophyseal system (HNS) of Long Evans (LE), Brattleboro heterozygote (HZ), and Brattleboro homozygote (DI) rats: (1) the arginine8-vasopressin (AVP)/dynorphin (DYN) neurons, and (2) the oxytocin (OT)/cholecystokinin (CCK8) neurons of the paraventricular and supraoptic nuclei, which project to the posterior pituitary. The regimen of chronic intermittent salt-loading (CISL) involved the replacement of 2% saline for normal drinking water for 18 hr/d. This protocol effectively increased plasma levels of AVP and OT in LE and HZ rats, oxytocin in DI rats, and maintained the posterior pituitary in a state depleted of AVP, OT, CCK, and peptides derived from pro-dynorphin: DYN A 1-17, DYN A 1-8, and DYN B 1-13. The ratio of pituitary DYN A 1-17 to DYN A 1-8 content in DI rats or in LE, HZ, and DI rats following 6 d of CISL suggests a preferential release of DYN A 1-17 during periods of chronic secretory activity. In response to chronic secretory activity, mRNAs for AVP, OT, DYN, and CCK increased 1.5-2-fold in all 3 AVP rat strains, with mRNAs for coexisting peptide hormones displaying parallel increases. Mutant AVP mRNA in the DI rat was expressed at very low levels and DYN mRNA in very high levels, with each of these mRNAs continuing to be regulated by CISL in a normal manner. These results suggest a regulatory relationship between AVP and OT neurons, in which vasopressin neurons are feedback-regulated by AVP, most likely via plasma osmolarity, and that oxytocin neurons are modulated by peptides derived from pro-dynorphin.

Animals↗
PubMed1987

DNA cross-linking responses of human malignant glioma cell strains to chloroethylnitrosoureas, cisplatin, and diaziquone.

Cell strains derived by culture of malignant glioma (astrocytoma grade III-IV) surgical specimens were tested for the production of DNA interstrand cross-links (ISC) and DNA-protein cross-links following treatment in vitro with 1-(2-chloroethyl)-1-nitrosourea, 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, carmustine), 1-(2-chloroethyl)-3-(2,6-dioxo-1-piperidyl)-1-nitrosourea (PCNU), cis-dichlorodiammineplatinum(II) (cisplatin), and 3,6-diaziridinyl-2,5-bis(carboethoxyamino)-1,4-benzoquinone (diaziquone). ISC and DNA-protein crosslinks were measured by means of the DNA alkaline elution technique. Large differences among the cell strains were observed in DNA cross-linking responses to individual agents. The DNA responses to the chloroethylnitrosoureas, cisplatin, and diaziquone were largely independent of each other, except for a weak correlation between ISC responses to chloroethylnitrosoureas were distributed bimodally, in accord with a phenotypic distinction between Mer+ and Mer- cells. ISC responses to cisplatin and diaziquone showed significant variation among cell strains, but the distributions were not bimodal. The results demonstrate the existence of diverse DNA cross-linking response patterns among cell strains from different tumors of a given histological type.

Aziridines↗
PubMed1987

Stressful life events preceding the acute onset of schizophrenia: a cross-national study from the World Health Organization.

This study reports on the findings from a WHO sponsored cross-national investigation of life events and schizophrenia. Data are presented from a series of 386 acutely ill schizophrenic patients selected from nine field research centers located in developing and developed countries (Aarhus, Denmark; Agra, India; Cali, Colombia; Chandigarh, India; Honolulu, USA; Ibadan, Nigeria; Nagasaki, Japan; Prague, Czechoslovakia; Rochester, USA). On a methodological level, the study demonstrates that life event methodologies originating in the developed countries can be adapted for international studies and may be used to collect reasonably reliable and comparable cross-cultural data on psychosocial factors affecting the course of schizophrenic disorders. Substantive findings replicate the results of prior studies which conclude that socioenvironmental stressors may precipitate schizophrenic attacks and such events tend to cluster in the two to three week period immediately preceding illness onset.

Adolescent↗
PubMed1987

Hyperketotic states due to inherited defects of ketolysis.

From the description of 2 unrelated patients with succinyl-CoA transferase (3-OAT) deficiency and 1 patient with acetoacetyl-CoA thiolase (AAT) deficiency, we have attempted to draw the clinical and metabolic consequences of such defects. The association of recurrent attacks of severe ketoacidosis with blood glucose levels generally high or normal, low lactacidemia and low ammonemia is the most common presentation of these disorders. In 3-OAT deficiency, a potentially fatal disorder, there is a permanent ketosis with the only excretion of 3-hydroxybutyrate, acetoacetate and 3-hydroxyisovalerate. AAT patients usually excrete, in addition to the usual ketone bodies, 2-methyl-3-hydroxybutyrate and tiglylglycine; 2-methyl-acetoacetate may also be present. Both conditions can be identified by enzymatic analysis in cultured fibroblast. These disorders can mimic diabetic ketoacidosis or salicylism and can easily be missed. The knowledge of these ketolytic defects must severely question the complacent diagnosis of 'fasting ketoacidosis' or 'idiopathic ketotic hypoglycemia', mainly when severe metabolic acidosis is present.

Acetoacetates↗
PubMed1987

Changes in autacoid and neuropeptide contents of lung cells in asbestos-induced pulmonary fibrosis.

The purpose of this study was to determine if asbestos-induced pulmonary fibrosis in the rat can affect the levels of autacoids and peptides in freshly isolated lung cells. Lung fibrosis was experimentally induced in rats by a single intratracheal instillation of 5 mg UICC Canadian chrysotile B fibers. Isolated lung cells were prepared from normal and from asbestos-exposed rats. These cells were also fractionated on bovine serum albumin (BSA) gradients. The contents of serotonin (5-HT), histamine (HIST), vasoactive intestinal peptide (VIP), and bombesin (BN) were measured in isolated total cell preparations as well as in density-fractionated cell populations from normal and from asbestos-exposed rats. Analysis of total lung cell preparation showed the presence of heterogeneous populations in normal rat lung. After asbestos exposure, there were significant changes in these cell populations as evidenced by significant increases in lymphocyte and mast cell numbers. In addition, increased levels of 5-HT, HIST, and VIP were observed in isolated lung cells obtained from rats exposed to asbestos 1, 3, and 6 months after instillation. BN content was unchanged 3 months after treatment, but was significantly increased at the 6 month-interval, suggesting a different pattern of response for this neuropeptide. Density fractionation of various cell populations further showed selective changes in specific cell fractions of lung after asbestos exposure. At 6 months, increased levels of 5-HT, HIST, and VIP were associated with cell fraction 7, whereas changes in BN content were found in cell fractions 2 and 3. Similarly, there was a significant increase of mast cells in fraction 7 at the 6-month interval.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Expressed emotion and schizophrenia in north India. I. Cross-cultural transfer of ratings of relatives' expressed emotion.

A bilingual rater was trained in English in a technique of assessing relatives emotional attitudes to patients, and was then required to rate material in Hindi without any further experience. This strategy revealed that the rating of critical comments, hostility and positive remarks could be transferred from English to Hindi without distortion. There were problems with the remaining two scales, over-involvement and warmth, but these were due to technical issues connected with rating and not to cross-cultural distortion.

Adolescent↗
PubMed1987

Expressed emotion and schizophrenia in north India. II. Distribution of expressed emotion components among relatives of schizophrenic patients in Aarhus and Chandigarh.

We measured the components of expressed emotion among two samples of relatives of first-contact patients from Aarhus (Denmark) and Chandigarh (India). The Danes were very similar in most respects to samples of British relatives, whereas the Indian relatives expressed significantly fewer critical comments, fewer positive remarks, and less over-involvement. Within the Chandigarh sample, city-dwellers were significantly more expressive than villagers of all EE components except over-involvement.

Adolescent↗
PubMed1987

Expressed emotion and schizophrenia in north India. III. Influence of relatives' expressed emotion on the course of schizophrenia in Chandigarh.

We conducted a one-year follow-up of patients who had made a first contact with psychiatric services in Chandigarh, North India, and had been assigned a diagnosis of schizophrenia. The expressed emotion (EE) of the patients' relatives was assessed early on. We found the same associations between the individual components of EE and relapse of schizophrenia as in previous Anglo-American studies, but only the association between hostility and relapse was statistically significant. Applying the same criteria as in the Anglo-American studies for 'high EE', we found a significant relationship between high EE and relapse rates. We conclude that the significantly better outcome of Chandigarh first-contact patients compared with a London sample is largely due to the significantly lower proportion of high-EE relatives in the North Indian sample.

Attitude to Health↗
PubMed1987

Asbestos-induced fibrosis in rats: increase in lung mast cells and autacoid contents.

Adult male Wistar rats were treated with one tracheal instillation of 5 or 10 mg chrysotile B asbestos fibers in 0.5 ml saline, or 0.5 ml saline only (controls). Rats were killed at 1, 3, and 6 months postinstillation. Serotonin and histamine were quantitated in lung tissue homogenate using high-performance liquid chromatography with electrochemical and fluorometric detection, respectively. Serotonin was also quantitated in the cytoplasm of grouped (NEB) and individual (NEC) neuroendocrine cells and in mast cells using formaldehyde vapor-induced fluorescence and microspectrofluorometry, and density indices of NEBs, NECs, and mast cells were determined. Tissue edema, fibrotic lesions, and medial hypertrophy of pulmonary arterioles were assessed morphometrically. Test rats had higher pulmonary serotonin and histamine levels than controls at 1, 3, and 6 months. They also had higher cellular serotonin in NEBs at 1 month, but not in NECs, and tended to have higher serotonin levels in mast cells at 6 months. Mast cell numbers were higher among tests at 1 and 3 months, whereas NEBs and NECs were unchanged by asbestos. There was no difference between tests and controls in the amount of tissue edema at any time. However, all test rats had distinct lung lesions characterized by peribronchiolar fibrosis and bronchiolitis obliterans. No such lesions were present among control rats. Typically, mast cells were located immediately beneath the epithelial basal lamina of the bronchiolar fibrotic projections and at their stalks, whereas no mast cells were noted beneath normal epithelium, indicating a role of mast cells in asbestos-induced peribronchiolar fibrosis. Moreover, arteriolar medial hypertrophy at all three ages in conjunction with the increased levels of serotonin was an index of putative chronic pulmonary hypertension. Our results suggest that asbestos-induced rises in serotonin and histamine are due primarily to increased numbers of mast cells.

Animals↗
PubMed1987

Computer-managed instruction: an alternative teaching strategy.

Computer-managed instruction is an instructional strategy whereby the computer is used to provide learning objectives, learning resources, and assessment of learner performance. Computer-managed instruction (CMI) aids the instructor in instructional management without actually doing the teaching. Central CMI themes discussed in the literature are individualization, behavioral objectives, and educational technology. The main objective of this study was to compare the outcomes of two teaching strategies: CMI versus the traditional lecture method. The learning objectives were based on specified theoretical content from a Health Assessment course for baccalaureate nursing students. The design of the study was quasi-experimental incorporating two experimental treatments applied to two groups on two occasions. Data analysis addresses differences between groups using CMI and the traditional lecture method. The variables examined were the cognitive performance of learners, the learner's attitude toward the instructional strategy, the learner's retention of knowledge, the time involved in mastering the learning objectives, and the relationship between learner characteristics and the effectiveness of the instructional strategy. No significant mean difference (p less than 0.05) was found between groups on cognitive performance as measured by written and practical examination scores. For these first-year baccalaureate nursing students, CMI did not prove to be a positive instructional method as assessed by the Attitude Questionnaire. The majority of students preferred a combination of instructional methods. There was no significant difference between groups in the time spent meeting the learning objectives by either teaching strategy. The findings suggested that these students preferred learning strategies that are traditional in nature and teacher directed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗