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R Hall

Publications and source records attributed to R Hall.

At least 19 recordsLinked to original sources
PubMed1992

Regulation of gene expression of rat skeletal muscle/liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. Isolation and characterization of a glucocorticoid response element in the first intron of the gene.

At least two genes encode isoenzymes of rat 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. Alternative splicing of one of these genes generates a skeletal muscle-specific transcript from an upstream promoter and a liver-specific transcript from a downstream promoter. A potent glucocorticoid response element was identified in the first intron of the gene, i.e. between liver exon I and exon II. The element is approximately 3.5 kilobase pairs (kb) downstream of the liver isoenzyme transcription start site and 13 kb upstream of exon II of the gene and confers dexamethasone-sensitive expression of chloramphenicol acetyltransferase (CAT) activity from a heterologous thymidine kinase promoter and from both homologous 5'-flanking regions of the gene. This glucocorticoid response element also exhibits androgen- but not estrogen-sensitive expression of CAT activity in HeLa cells cotransfected with the appropriate receptor expression vector. DNase footprint and sequence analysis revealed that the element is comprised minimally of two adjacent 15-mer glucocorticoid receptor dimer binding sites situated in opposite orientations. Glucocortcoid regulation of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase gene expression in liver and skeletal muscle is mediated by a single complex glucocorticoid response element located in the first intron of the skeletal muscle/liver gene.

Animals↗
PubMed1992

Delayed root canal therapy: an analysis of treatment over time.

A retrospective study of 898 teeth receiving root canal therapy was performed to document the sequelae of delayed completion of root canal treatment. Teeth were categorized into a prompt treatment group and a delayed treatment group. Comparisons of prompt and delayed treatment groups were made with regard to preoperative pain, interappointment emergencies, postobturation pain, and final treatment. Findings from this study show that a palliative endodontic procedure is an extremely effective treatment. However, 56% of teeth with incomplete root canal therapy eventually were extracted compared with 2 to 3% for the root canal filling treatment groups. By emphasizing the potential loss of the tooth rather than the potential of interappointment emergencies, the clinician may be more effective in achieving compliance among patients receiving delayed treatment.

Acute Disease↗
PubMed1992

Clinical pathology testing recommendations for nonclinical toxicity and safety studies. AACC-DACC/ASVCP Joint Task Force.

Clinical pathology testing in nonclinical toxicity and safety studies is an important part of safety assessment. In recent years, clinical laboratory testing has rapidly expanded and improved. Some government regulatory agencies provide guidelines for clinical pathology testing in nonclinical toxicity and safety studies. To improve these testing guidelines and the resultant safety assessments, the American Association for Clinical Chemistry's Division of Animal Clinical Chemistry and the American Society for Veterinary Clinical Pathology formed a joint committee to provide expert recommendations for clinical pathology testing of laboratory species involved in subchronic and chronic nonclinical toxicity and safety studies. These recommendations include technical recommendations on blood collection techniques and hematology, serum chemistry, and urinalysis tests.

Animals↗
PubMed1992

Reversible adrenocorticotropin deficiency due to probable autoimmune hypophysitis in a woman with postpartum thyroiditis.

The natural history and pathogenesis of lymphocytic hypophysitis remain poorly understood. We describe a 34-yr-old woman with postpartum thyroiditis and ACTH deficiency, studied at monthly intervals for 18 months after pregnancy. A significant titer of thyroid peroxidase autoantibodies was detected at 16 weeks gestation, and she was recruited into a prospective study of postpartum thyroid function. Four months postpartum she developed mild hyperthyroidism [free T4 (fT4), 27 pmol/L; TSH, less than 0.2 mU/L] and showed a rise in thyroid peroxidase and thyroglobulin autoantibodies. At 9 months postpartum, serum fT4 and fT3 levels were low normal (8.0 and 1.7 pmol/L, respectively), but TSH was not raised (0.4 mU/L). Subsequent investigation showed a low basal plasma cortisol level (28 nmol/L) in association with undetectable ACTH, and subnormal cortisol responses to depot Synacthen (535 nmol/L at 6 h) and hypoglycemia (peak, 145 nmol/L). FSH, LH, GH, and PRL function and computerized tomography of the pituitary were normal. Retrospective analysis of serum samples taken throughout the postpartum year showed developing hypocortisolemia between 3-9 months postpartum. Each sample was also tested for pituitary autoantibodies using a specific indirect immunofluorescent assay; none was detected. The ACTH deficiency recovered spontaneously, with normal cortisol responses to depot Synacthen (greater than 1380 at 6 h) and hypoglycemia (peak, 590) 14 and 18 months postpartum, respectively. This case illustrates that postpartum pituitary deficiencies are potentially reversible. The pattern of pituitary deficit and postpartum thyroiditis supported a diagnosis of autoimmune hypophysitis.

Adrenocorticotropic Hormone↗
PubMed1979

Effects of bromocriptine on pituitary tumour size.

In a prospective study designed to assess the influence of bromocriptine on pituitary tumour size 12 patients with pituitary tumours, eight of whom had suprasellar extensions, were treated for three months with 20 mg of bromocriptine daily after a gradual increase to this dose. The group comprised eight women and four men, five with prolactin-secreting adenomas, four with acromegaly, two with functionless adenomas, and one with Nelson's syndrome. All five patients with prolactin-secreting adenomas showed a reduction in pituitary tumour size as assessed by computerised tomography and metrizamide cisternography accompanied by a fall in prolactin concentrations and clinical and biochemical improvement in their hypopituitarism. One patient in this group had a visual-field defect before treatment, and this resolved. There was no radiological evidence of reduction in tumour size in the remaining seven patients, though this might refect the fairly short duration of treatment, particularly in view of the ancillary evidence of clinical, biochemical, and visual-field improvement in some of the patients. These results emphasise the potential value of bromocriptine in treating patients with large prolactinomas or recurrences of such tumours after previous chiasmal decompression and conventional external megavoltage irradiation on the pituitary.

Adult↗
PubMed1979

Effect of irradiation on thyroid-autoantibody production.

Irradiated lymphocytes have been found to stimulate thyroid-autoantibody synthesis by lymphocyte cultures. It is proposed that a similar effect is involved in the increased autoimmune response which follows radioiodine treatment for Graves' disease.

Antibody-Producing Cells↗
PubMed1979

The irritancy of chlorhexidine gluconate in the genital tract of the mare.

Uterine irrigation was carried out in eight Welsh pony mares using 50 ml of chlorhexidine gluconate solution diluted to give active ingredient concentrations of 0.25 per cent to 2 per cent. Treatment was repeated up to twice in mares showing no adverse effects and irritancy of treatment judged on clinical symptoms and uterine biopsy. Results indicated the inadvisability of using a higher concentration than 0.25 per cent. Three daily applications of a diluted surgical scub solution containing 2 per cent chlorhexidine gluconate to the penis of an arab stallion failed to produce symptoms or irritation. An in vitro minimum inhibitory concentration test performed with the contagious equine metritis organism confirmed its high sensitivity to both chlorhexidine gluconate preparations.

Animals↗
PubMed1979

Developmental protein malnutrition: influences on the central nervous system of the rat.

Our group has been carrying out interdisciplinary studies on the effects of prenatal and postnatal protein malnutrition on the developing rat brain. Anatomical, physiological, biochemical and behavioral approaches using the same animal model have revealed that protein malnutrition affects the brain at various levels, i.e., (1) anatomical, as revealed by Golgi findings of deranged dendritic trees on analysis of cortical and subcortical areas; (2) physiological, as revealed by delayed sleep pattern maturation, disturbances in seizure thresholds, slowing of sensory cortico-cortical and thalamocortical evoked potentials, and changed power in hippocampal theta activity; (3) biochemical, as revealed by marked increases in biogenic amines dating from birth, as well as modifications in tryptophan metabolism; and (4) behavioral, as revealed by various changes in responses to different kinds of aversive stimulation. Reversal studies have revealed that many changes are permanent and not amenable to nutritional rehabilitation even at birth, which is before the brain growth spurt in the rat. Our paradigm closely mimicks the human condition of low level, chronic protein undernutrition and thus reveals the underlying disturbances due to malnutrition. The dietary reversal studies are attempts at pin-pointing critical brain growth periods, beyond which recovery of functions is not possible.

Animals↗
PubMed1979

Treatment of Cushing's disease with adrenal blocking drugs and megavoltage therapy to the pituitary.

Eighteen patients with Cushing's disease were seen over a 40-month period and considered for treatment by pituitary irradiation and adrenal blocking drugs. Fourteen patients entered the study and each received megavoltage therapy to give a mean dose of 4600 rad to the pituitary over 31 days. Each patient was treated for one (two patients) or two (12 patients) years with one or both of the adrenocortical enzyme inhibitors, metyrapone or aminoglutethmide to suppress cortisol secretion. Doses were adjusted to maintain urinary free cortisol secretion below 300 nmol/24 h. One patient failed to complete the trial. Normal urinary free cortisol excretion and plasma cortisol concentration were maintained after treatment in eight of the remaining 13 patients after therapy. Only one patient required cortisol replacement and normal menstrual function was restored in five of the six women. The remaining five patients relapsed and four were subsequently treated by total adrenalectomy. It was noted that the patients who responded to treatment were substantially younger than the therapeutic failures. It is suggested that this treatment is most useful in the management of younger patients.

Adrenocorticotropic Hormone↗