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Biomedical subjects

M McNally

Publications and source records attributed to M McNally.

34 records · Page 2Linked to original sources

Nuclear localization of type 1 aldosterone binding sites in steroid-unexposed GH3 cells.

The nuclear localization of unoccupied oestrogen receptors has been demonstrated in MCF 7 (human breast tumour) cells by immunocytochemistry, and in GH3 (rat pituitary tumour) cells by enucleation techniques. The present study shows, by similar enucleation techniques, that high affinity (Type 1) aldosterone binding sites are similarly located in the nucleus of steroid-unexposed pituitary GH3 cells. It is, therefore, suggested that such high-affinity Type 1 sites, which are mineralocorticoid receptors in the kidney and glucocorticoid receptors in the hippocampus, are nuclear-associated proteins in the absence of steroid and are found in the cytosol compartment only upon cell disruption.

Cell Line↗

Anterior pituitary cells from Brattleboro (di/di), Long-Evans and Sprague-Dawley rats contain immunoreactive arginine vasopressin.

A radioimmunoassay specific for arginine-vasopressin (AVP) was used to establish the presence of immunoreactive (ir)-AVP in extracts of anterior pituitary glands from Sprague-Dawley (SD) and Long-Evans (LE) rats (3.05 +/- 1.0 and 1.66 +/- 0.9 ng/gland, respectively). Lower levels of ir-AVP (0.56 +/- 0.26 ng/gland) were detected in anterior pituitary gland extracts from rats with hereditary diabetes insipidus (Brattleboro; di/di). The anterior pituitary gland ir-AVP from each rat strain was further characterized by reverse-phase high-performance liquid chromatography (RP-HPLC). In each case the major peak of immunoreactivity co-migrated with synthetic AVP. By peroxidase-antiperoxidase immunocytochemistry, sparsely distributed cells containing ir-AVP were localized in anterior pituitary sections. Levels of ir-AVP in primary cultures of anterior pituitary cells (from SD rats) increased from 52 +/- 5 pg/10(6) cells at 2 days in vitro to 152 +/- 17 pg/10(6) cells at 3 days; during this period 56 +/- 6 pg/ml ir-AVP was secreted into the culture medium. Fewer than 1% of the cells in these cultures were immunostainable for AVP. These data indicate that the anterior pituitary gland of the Brattleboro, Long-Evans and Sprague-Dawley rat contains ir-AVP, and that there is synthesis and secretion of this peptide in primary cultures of anterior pituitary cells in vitro.

Animals↗

Pro-opiomelanocortin messenger ribonucleic acid and posttranslational processing of beta endorphin in spleen macrophages.

We have previously demonstrated low levels of immunoreactive (ir)-beta-endorphin (beta-EP) and ir-ACTH in a subpopulation of mouse spleen macrophages, which is consistent with an involvement of opioid peptides in modulation of immune responses. Gel chromatography studies suggested the presence of an approximately 3.5,000-molecular weight (mol wt) species, putatively beta-EP, an approximately 11.5,000-mol-wt species, putatively beta-lipotropin, and a higher molecular weight species (putative beta-EP precursor, pro-opiomelanocortin (POMC). In this study we have extended our original findings by demonstrating the presence of messenger RNA for POMC by the use of a complementary DNA probe and Northern blot analysis of extracts of mouse and rat spleen. In addition, using high performance liquid chromatography (HPLC), we have shown that the major endorphin species in mouse spleen macrophages is beta-EP1-31, and that there are smaller amounts of each of the acetylated forms, N-acetyl-beta-EP1-16 (alpha-endorphin), N-acetyl-beta-EP1-17 (gamma-endorphin), N-acetyl-beta-EP1-27, and N-acetyl-beta-EP1-31. We interpret these studies as showing that (a) the spleen is an organ of POMC synthesis and that (b) the predominant COOH-terminal product of macrophage POMC is the opiate-receptor active species beta-EP1-31.

Animals↗

Estrogen regulation of kallikrein gene expression in the rat anterior pituitary.

Using a rat pancreatic kallikrein cDNA probe (pcXP39), previously shown to hybridize to kallikrein mRNA in a variety of tissues, we have explored the control of kallikrein gene expression in rat anterior pituitary. Intact female rats have substantially higher levels of AP kallikrein mRNA than intact males; male levels are unaffected by castration, whereas female levels fall markedly postovariectomy. Administration of estradiol benzoate to intact male or ovariectomized female rats causes an increase in anterior pituitary levels of kallikrein mRNA. Since the pattern of responsiveness parallels that of PRL, we have studied GH3 cells grown in the presence and absence of estradiol; in neither instance was kallikrein mRNA above detection limits. Parallel changes were seen on Northern blots and by hybridization histochemistry; on emulsion autoradiography of pituitary sections, scattered positive cells were seen, but precise definition was not possible. We conclude that whereas in the submaxillary gland kallikrein gene expression appears androgen dependent and in the kidney is postulated to be mineralocorticoid regulated, in the anterior pituitary expression of the gene is under estrogen control; and that the local role(s) of pituitary kallikrein, whether precursor processing, control of blood flow, or other effects, would, in turn, appear to be modulated by estrogen in vivo.

Animals↗

Overlapping but not identical protein synthetic domains in cardiovascular cells in response to glucocorticoid hormones.

We have compared, by two-dimensional gel electrophoresis, the effects of glucocorticoids on newly synthesized proteins of cultured cardiovascular cells (rat synthetic- and contractile-state vascular smooth muscle, rat cardiac muscle and non-muscle, and bovine endothelium) and rat hepatoma (H4) cells, as a non-cardiovascular target. In each cell type, glucocorticoids consistently affected a particular set of proteins termed the glucocorticoid domain for that target tissue. Cardiovascular cells exhibited overlapping but non-identical glucocorticoid domains; these domains varied in number of proteins, proportion of induced and repressed proteins, and overlap (extent of shared protein responses) between the various cardiovascular cell types studied. On physico-chemical and co-electrophoresis data the glucocorticoid domain of cardiovascular cells also overlapped with that of hepatoma cells, but to a lesser extent. The glucocorticoid domain in cardiac muscle cells included five proteins not found in cardiac non-muscle cells. Contractile-state vascular smooth muscle cells showed some, but not all, of the proteins affected by glucocorticoids in synthetic-state cells; the only response seen in the contractile but not vascular smooth muscle cells was a protein of Mr-52K and pI-5.3, which was also induced in spontaneously contractile cardiac muscle. Further characterization of contractile and synthetic vascular smooth muscle and cardiac muscle proteins affected by glucocorticoids is necessary to ascertain their role(s) in specialized cardiovascular functions.

Animals↗

Uniform distress.

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Clothing↗

Neonatal abstinence syndrome.

A 12 month review of infants admitted with neonatal abstinence syndrome to a neonatal intensive care unit was undertaken. The relationship of maternal drug abuse to symptoms, the effectiveness of pharmacologic agents in controlling symptoms and the length of inpatient stay were investigated. A retrospective review of maternal and infant records was performed. Those infants with a serial Finnegan score greater than 8 were treated. Pharmacologic treatment was oral morphine sulphate (0.2 mg 4-6 hourly), phenobarbitone (3-7 mgs/kg/day), or combination of the above. 43 infants were admitted to the hospital during the year. The average maternal age was 24.6 years, (18-34 years). Drug use volunteered by the mothers was methadone alone in 6 cases, methadone and benzodiazepines in 14, methadone and heroin and benzodiazepines in 7, methadone and heroin in 10, heroin alone in 2, and other multiple drug use including oral morphine sulphate, dothiepin and cannabis in 4. Average gestational age was 40.3 (35-42 weeks). The average birthweight was 2.81 kgs (1.89-3.91 kgs). Time to onset of withdrawal symptoms was 2.8 (1-13) days. The duration of pharmacologic treatment (oral morphine sulphate and/or phenobarbitone) was 21.8 (1-62) days. The total hospital stay for the 43 infants was 1,011 days. This study confirms that polydrug abuse is the commonest type of drug abuse in Dublin. The duration of withdrawal symptoms is loosely related to drug type, but increasing duration of symptoms is noted for infants exposed to benzodiazepines. Our experience would favour the use of morphine sulphate to treat pure opiate withdrawal symptoms. Over the 12-month period, there was an average occupancy of 3 beds per day in the paediatric department.

Adolescent↗