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Biomedical subjects

E Campbell

Publications and source records attributed to E Campbell.

At least 109 records · Page 6Linked to original sources
PubMed1986

Effects of 6-hydroxydopamine on the hypothalamo-pituitary-adrenocortical axis.

Female rats were treated with two intraventricular injections each of 350 micrograms 6-hydroxydopamine (6-OHDA) and used for experiment 4 or 14 days later. The response to laparotomy, as assessed by subsequent in vitro corticosterone release, was unaffected by the drug, but that to the smaller stress of a skin cut was significantly reduced. Both fast and delayed feedback responses to corticosterone administration were still evident in 6-OHDA-treated animals. When determined 14 days after treatment, hypothalamic concentrations of epinephrine (E) and norepinephrine (NE) were reduced by 46 and 84%, respectively. There was no significant change in content of immunoreactive corticotropin-releasing factor (CRF-41). The acetylcholine-stimulated release of CRF bioactivity from control hypothalami incubated in vitro was significantly inhibited by E or NE, with E being at least 10 times more potent on a molar basis. This effect of NE was enhanced in hypothalami removed from 6-OHDA-treated rats, complete inhibition of acetylcholine-stimulated release of CRF being produced by 0.6 nM NE, as opposed to 6.0 nM for untreated controls. At the level of the anterior pituitary gland, tissue content of adrenocorticotropin (ACTH) was unaffected by treatment, but that of luteinizing hormone (LH) in the same tissues was significantly increased. The corticotrophic response of fragments of the gland incubated or perifused in vitro to hypothalamic extract, CRF-41, arginine vasopressin or E was reduced. In contrast, the response of the tissue to gonadotropin-releasing hormone (GnRH) added in vitro was not significantly affected.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1985

Diurnal variations in responsiveness of the hypothalamo-pituitary-adrenocortical axis of the rat.

Hypothalami, anterior pituitary gland segments and adrenal glands were removed from female Wistar-derived rats decapitated at various times of the day. Blood and tissue hormone concentrations were measured and the tissues challenged with appropriate stimuli in vitro. Both bioactive and immunoreactive corticotrophin-releasing factor (CRF) content of the hypothalami were significantly higher in the evening than in the morning, as was the basal release of bioactive CRF in vitro. The response of the hypothalami to serotonin or acetylcholine added in vitro did not change with time of day. Basal bioactive and immunoreactive adrenocorticotrophin (ACTH) release from the anterior pituitary gland was significantly increased in the evening, as was the response to synthetic ovine CRF in vitro. Plasma ACTH concentrations in intact rats given crude CRF (hypothalamic extract) in vivo were higher in the evening at all times after injection tested, but this difference was markedly reduced in animals with mediobasal hypothalamic lesions. Corticosterone released basally from adrenal glands in vitro was significantly increased in the evening and the response to added ACTH 1-24 was slightly enhanced. For adrenal glands removed from lesioned rats, the pattern was reversed, corticosterone release in vitro being lower in the evening for all doses of ACTH added. Similarly in vivo, in intact rats given ACTH 1-24, plasma corticosterone concentrations and corticosterone release in vitro from adrenal glands removed after the injection were higher in the evening. After the placement of basal hypothalamic lesions, the situation was reversed, the response to ACTH administration in vivo being greater in the morning.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1985

Ovulation induction with pulsatile intravenous GnRH.

Human menopausal gonadotropin has been the treatment of choice for hypogonadotropic hypogonadism patients who fail ovulation induction with clomiphene citrate. Several authors have reported successful ovulation induction with the use of gonadotropin releasing hormone (GnRH). We used commercially available GnRH (Factrel, Ayerst Laboratories) and the Auto Syringe AS6H Infusion Pump for ovulation induction in such patients. Eight patients completed 15 cycles of pulsatile intravenous GnRH therapy. A mean of 12.2 days of therapy was required per cycle. Basal body temperatures and ultrasound documented ovulation of a single, dominant follicle in 12 cycles (80%). There were four singleton pregnancies. The overall corrected pregnancy rate was four pregnancies for ten cycles (40%) in six patients (67%). No complications were observed, and the cost of care was one-third that of human menopausal gonadotropin at our institution.

Amenorrhea↗
PubMed1984

Recovery of the hypothalamo-pituitary-adrenocortical axis in the rat after long-term dexamethasone treatment.

Male rats were treated for 14 days with dexamethasone (2.6 mumol/l in the drinking water) and killed at various times after withdrawal of the drug. Some animals were subjected to stress (ether or sham adrenalectomy) just before killing. The recovery of responsiveness of the components of the hypothalamo-pituitary-adrenocortical axis was assessed by measuring plasma and tissue concentrations of hormones, and the response of the tissue in vitro to appropriate stimuli. In vitro, bioactive corticotrophin-releasing factor (CRF) release in response to acetylcholine and adrenal corticosterone release in response to adrenocorticotrophin (ACTH) were significantly suppressed until 3 days after withdrawal. However, release of immunoreactive or bioactive ACTH in response to ovine CRF or hypothalamic extract did not return to normal until day 5. This was correlated with a reduction in pituitary immunoreactive ACTH content and bioactive plasma ACTH, which were suppressed until days 5 and 4, respectively. No change in hypothalamic immunoreactive CRF content could be detected after treatment, or after stress (ether or sham adrenalectomy) in either treated or control animals. Stress (ether) had no effect on the subsequent response of the anterior pituitary gland in vitro to ovine CRF. The large rises in plasma ACTH and adrenal corticosterone measured after stress (ether) in control animals were completely abolished after dexamethasone treatment and did not return to control values until 5 days after withdrawal. Therefore, it appears that after cessation of chronic dexamethasone treatment in the rat, the responsiveness of the hypothalamus and adrenal gland return to normal before that of the pituitary gland.

Adrenalectomy↗
PubMed1982

The effect of hemoglobin F upon glycosylated hemoglobin determinations.

Glycosylated hemoglobin (Hgb A1) determinations have been advocated for monitoring the control of diabetes mellitus. The prevalent method today for measuring Hgb A1 for most clinical laboratories has been a "mini-column" utilizing ion exchange chromatography. It has been stated that hemoglobin F (Hgb F) will elute with Hgb A1 and interfere with Hb A1 determinations. This study was designed to determine the quantitative effects of Hgb F upon Hgb A1 determinations. Thirty per cent of the study group had elevated Hgb A1 levels at 2% Hgb F concentration, 66% at 3% Hgb F concentration, and all individuals had elevated Hgb A1 levels at Hgb F concentrations of 4% or greater. The relationship of Hgb F to Hgb A1 concentration was not a simple identity, but could be represented by the equation y = 6.03 + 1.24x. If the ion exchange chromatography methodology is used, Hgb F levels should be determined whenever Hgb A1 levels are elevated, particularly in populations where increased Hgb F levels also might be encountered. The authors determined Hgb F levels whenever the concentration of Hgb A1 was 10% or greater. In their population, they found that approximately 1.5% of samples with elevated Hgb A1 concentrations had increased (greater than 2%) Hgb F levels.

Chromatography↗
PubMed1982

Evidence for in vivo internalization of human leukocyte elastase by alveolar macrophages.

Cell lysates from cultured human alveolar macrophages contain detectable amounts of an elastinolytic enzyme. Although particulate elastin was solubilized only after prolonged incubations, lysates readily hydrolyzed T-OC-alanyl-p-nitrophenol-ester. Hydrolysis of the latter substrate was inhibited by the leukocyte elastase site-specific inhibitor, N-ac-(ala)4-chloromethyl ketone. In addition, radioimmunoelectrophoresis of concentrated alveolar macrophage lysates, previously incubated with 3H diisopropyl-phosphofluoridate (DFP), revealed the presence of DFP binding material that comigrated with inactivated human leukocyte elastase. Human leukocyte elastase can cause lung lesions resembling pulmonary emphysema in experimental animals; therefore, the clearance of this enzyme by alveolar macrophages may represent a significant route for the removal of this potentially pathogenic enzyme from the lung.

Cells, Cultured↗
PubMed1981

Carcinoma of the oesophagus associated with membrano-proliferative glomerulonephritis.

Nephrotic syndrome has been observed in association with different types of neoplasia. This appears to be the first report of the occurrence of the nephrotic syndrome due to membrano proliferative glomerulonephritis in association with carcinoma of the oesophagus. Although proteinuria was present before excision of the tumour, the nephrotic phase occurred subsequently. Eventually it disappeared leaving the patient with a clear urine and biochemical and histological improvement of the renal lesion (including immunofluorescent and electronmicroscopy studies). Possible mechanisms responsible for the nephrotic syndrome in this case are discussed.

Carcinoma, Squamous Cell↗
PubMed1980

Factor VII inhibitor.

Factor VII inhibitor activity was identified in a 66 year old man with probable bronchogenic carcinoma. Initial studies indicated a normal partial thromboplastin time (PTT) and a prothrombin time (PT) prolongation which increased with incubation. PT correction failed to occur with 50 per cent normal plasma in vitro and 2 U of fresh frozen plasma in vivo, indicating inhibitor activity. Specific factor assay levels fell within normal limits except for a factor VII level of 30 per cent. Subsequent evaluation with antiglobulin studies suggested an inhibitor of immunoglobulin G [IgG] origin.

Aged↗
PubMed1976

A comparison of histocompatibility antigens in dermatitis herpetiformis and adult coeliac disease.

The incidence of histocompatibility antigens HL-A, 4a and 4b was studied in thirty-eight patients with dermatitis herpetiformis (DH) and thirty-six patients with adult coeliac disease (ACD). The 4b antigen was found in all the DH and ACD patients. HL-A 8 was found in 89% of patients with ACD--similar to the incidence reported in previous studies--and in 79% of patients with DH, a higher incidence than in previous studies which may be due to stricter criteria being used here to diagnose DH. There was no significant difference in the incidence of HL-A 8 between those patients with DH whose small intestinal biopsies appeared macroscopically abnormal and those with a normal macroscopic appearance. These findings suggest that patients with DH form a single disease group and do not support the concept previously postulated that there are two groups of patients with DH, one with an increased incidence of HL-A 8 antigen similar to that in ACD who have a gluten sensitive enteropathy (GSE), and another with a normal incidence of HL-A 8 antigen and without enteropathy.

Celiac Disease↗