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Biomedical subjects

G F Joplin

Publications and source records attributed to G F Joplin.

At least 19 recordsLinked to original sources
PubMed1992

Effects of treatments by calcium and sex hormones on vertebral fracturing in osteoporosis.

Lateral radiographs of the thoracic and lumbar spine were taken periodically in 49 patients with osteoporosis. Thirty patients were postmenopausal, and 19 nonmenopausal with osteoporosis due to steroids, male hypogonadism, alcoholism, thyrotoxicosis or unknown cause. Patients were studied before, during and after treatment with high calcium alone, or with combined calcium and sex steroids. Calcium was given as effervescent calcium lactate gluconate, and sex hormones as oestradiol valerate, testosterone oenanthate, or methenolone oenanthate. A total of 964 films covering 409 patient-years were available for measurement. On each vertebra, deformity due to loss of anterior height was measured and assigned to one of four grades. For the time interval between each consecutive pair of films, a patient's vertebral fracture rate score was calculated and expressed per thousand patient-years. In comparison with the corresponding pretreatment fracture rate score, both the postmenopausal and the nonmenopausal groups who had not received sex hormones previously, failed to show significant changes (p = 0.144; p = 0.017) on high calcium alone during mean periods of 4.3 and 2.8 years respectively. If the first 2 years on high calcium were excluded for the postmenopausal group, they still failed to show a reduction in fracture rate score (observed for a mean period of 5.0 years; p = 0.04). When treated with combined calcium and sex hormones, both postmenopausal and nonmenopausal groups showed a lower fracture rate score of 20 and 207 respectively when compared with the pretreatment levels of 1500 and 1697 (in mean treatment periods of 3.2 and 4.4 years; p less than 0.001 in each case). When given high-dose calcium alone, but after treatment with sex hormones as well, the postmenopausal group showed no change in fracture rate score from pretreatment (in a mean of 3.1 years; p = 0.069); however the nonmenopausal group still showed a significant reduction in fracture rate score from 1697 to 42 over a mean period of 2.3 years (p = 0.001). The postmenopausal group, after stopping all treatment, showed a higher fracture rate score of 1286 (in a mean of 2.6 years) than did those on combined calcium and sex hormones, in whom the fracture rate score was 20 (in a mean of 3.2 years; p = 0.008). A subgroup of 11 patients with osteoporosis of both the menopausal and nonmenopausal types, had data both before (in a mean of 5.5 years) and during (for a mean of 2.5 years) treatment with calcium alone; the fracture rate scores were 1473 and 918 (p = 0.247).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Heel pad thickness is an insensitive index of biochemical remission in acromegaly.

The value of serial measurements of heel pad thickness as a clinical predictor of biochemical remission in acromegaly was assessed in 25 patients followed for up to 20 years after treatment by interstitial irradiation using yttrium-90 implantation. Growth hormone (GH) levels fell to 50% of baseline values within 12 months of therapy (P less than 0.001) and to 21% at 5 years, reaching normal levels after 10 years, constituting a biochemical cure maintained to the end of the study period. By contrast, heel pad thickness remained relatively stable, falling to 95% of baseline after 5 years (P less than 0.05) and to 87% after 20 years. There was no overall correlation between the measured parameters (r = 0.033, P greater than 0.05) suggesting that heel pad thickness is a poor predictor of biochemical remission in acromegaly.

Acromegaly↗
PubMed1990

An evaluation of the distinction of ectopic and pituitary ACTH dependent Cushing's syndrome by clinical features, biochemical tests and radiological findings.

The efficiency of various laboratory and radiological investigations in the differentiation of ectopic from pituitary dependent Cushing's syndrome was studied, based on findings in 23 patients with verified Cushing's disease and seven patients with the ectopic ACTH syndrome. Clinical features strongly favouring the ectopic type were male sex and history for less than 18 months. Basal biochemical features strongly indicating the ectopic syndrome included plasma K+ less than 3.0 mmol/l and HCO3 greater than 30 mmol/l; serum cortisol at 9 a.m. or midnight of greater than 800 nmol/l; urine free cortisol greater than 1300 nmol/24 hours; plasma ACTH greater than 100 ng/l. In the high-dose dexamethasone suppression test, suppression by less than 50 per cent of 9 a.m. serum cortisol, urine free cortisol or 17-oxogenic steroids was usually indicative of an ectopic source of ACTH. A mean suppressed value of greater than 450 nmol/l for the 9 a.m. and midnight cortisol combined occurred in all of those with the ectopic syndrome, but in none of the 23 patients with Cushing's disease. For urine free cortisol, a mean suppressed value of less than 1000 nmol/24 hours was found in all patients with Cushing's disease, but in none of those in the ectopic group. In the metyrapone test, there was an increase of less than or equal to 3-fold in 11-deoxycortisol at 24 hours in patients with ectopic ACTH; the increase was greater than 3-fold in all but one of the patients with Cushing's disease. Failure to respond to either dexamethasone or metyrapone was found in only one of the patients with Cushing's disease (Patient 16); in the ectopic group, all patients except Patient D failed to respond to either test. It is concluded that patients presenting with clinically obvious Cushing's syndrome along with measurable plasma ACTH can be reliably divided by conventional tests into those that are driven from the pituitary and those driven by ectopic ACTH.

ACTH Syndrome, Ectopic↗
PubMed1990

Serum testosterone levels in women with Cushing's disease.

Serum testosterone was measured pre- and post-operatively in 31 women who obtained remission of Cushing's disease following treatment by interstitial irradiation of the pituitary gland. The mean serum testosterone was initially elevated at 3.35 nmol/l, with values ranging from 0.7 to 14.4 nmol/l. Following treatment the mean serum testosterone fell to 1.42 nmol/l (i.e. normal) and all but one of the 15 patients with initially elevated pre-treatment values obtained normal levels. The pretreatment testosterone concentrations correlated significantly (r = 0.47; p = 0.019) with the midnight ACTH concentration. The likely determinant of the raised serum testosterone would appear to be the intensity of the ACTH drive, although an individual's inherent sensitivity to ACTH may also be a factor.

Adolescent↗
PubMed1990

The effectiveness of external beam radiotherapy for acromegaly is not affected by previous pituitary ablative treatments.

Thirty-three acromegalic patients were treated with radiotherapy and followed up for at least 3 years (mean 6 years, range 3 to 12). Seventeen had not had previous pituitary ablative therapy and 16 had. The mean GH level for these two groups before radiotherapy was comparable at 98 and 119 mIU/l. The observed frequency of reaching less than 10 mIU/l was 53% and 75% of patients in the two groups, respectively, the mean observed falls in growth hormone level were 81 and 85% of the initial level, and the calculated exponential decline rate of GH level was 72 and 52% per year. Considering all 35 patients, requirement for pituitary hormone replacement therapy increased from 15 patients before radiotherapy to 20 after radiotherapy, being mostly those who had had prior ablative therapies. There were no complications attributable to the radiotherapy treatment. It appears that radiotherapy is equally efficacious whether a prior unsuccessful ablative procedure had been used or not.

Acromegaly↗
PubMed1990

Immediate and long-term effects on hormone levels following bites by the Burmese Russell's viper.

Studies of anterior pituitary function were made in victims of a bite by the Burmese Russell's viper, who had required admission to a renal unit. Twenty patients at the stage of the acute illness were studied using a single blood sample for several hormone assays. None showed normal levels of all hormones measured. As acute severe illness can have a profound effect on the levels of these hormones, it is only possible to conclude that the results were compatible with although not diagnostic of anterior pituitary failure. Twelve survivors were assessed at eight to 226 weeks after envenoming, by hormone measurement in a basal sample, and a combined pituitary reserve function test with TRH, GnRH, and insulin hypoglycaemia. All but one showed some deficit in pituitary hormone secretion. Seven had already been started on thyroid replacement therapy or corticosteroids. Three survivors were assessed in the acute stage and later and each had similar findings on both occasions. Three survivors who were followed up and assessed with a combined pituitary reserve function test on two occasions had similar results each time. There was no sign of recovery. It seems that severe envenoming may be associated with anterior pituitary failure. Results from five autopsies showed that the lesion was haemorrhagic anterior pituitary necrosis. An additional mechanism may be direct action of the venom upon the function of anterior pituitary cells. We conclude that severely affected victims should be considered at risk of pituitary insufficiency.

Acute Disease↗
PubMed1989

Assessment of computed tomographic artefact in the pituitary fossa following needle implantation of radioactive rods.

Computed tomographic scans of the pituitary fossa following treatment of pituitary tumours by interstitial irradiation were reviewed for the degree of metallic artefact created by the rods. Among 50 patients treated with 90Y rods alone, none showed artefact to a degree that caused technically unsatisfactory images in coronal or axial cuts. Among the seven patients who had been treated with 198Au, either alone (two patients) or with both 198Au and 90Y rods (five patients), six had severe artefact and in five of these the images were technically unsatisfactory in both coronal and axial slices. We conclude that following implantation of 90Y rods, the currently preferred isotope, the pituitary fossa can be satisfactorily assessed by computed tomography.

Adenoma↗
PubMed1989

Use of adrenal arterial embolization in severe ACTH-dependent Cushing's syndrome.

The management of a patient with severe Cushing's syndrome due to ectopic ACTH produced by a medullary carcinoma of the thyroid is described. Initial treatment with maximal adrenolytic medical therapy and two attempts at bilateral adrenal venous infarction had failed to control the disease, and she was at that time unfit for surgery. Subsequent use of bilateral adrenal arterial embolization enabled medical therapy to produce sufficient control of the Cushing's syndrome to allow bilateral adrenalectomy to be performed successfully, with resultant cure of the excessive cortisol production.

ACTH Syndrome, Ectopic↗
PubMed1989

Burmese Russell's viper venom causes hormone release from rat pituitary cells in vitro.

Acute and chronic hypopituitarism is associated with severe envenoming by the Burmese Russell's viper. We have demonstrated that in vitro, Burmese Russell's viper venom (0.1-10 micrograms/ml) causes a dose-dependent release of GH, TSH and ACTH from dispersed rat anterior pituitary cells in culture. At 10 micrograms/ml, venom causes a significant increase in the release of GH (344%, P less than 0.001), TSH (168%, P less than 0.005) and ACTH (greater than 700%, P less than 0.001). We have also shown that the component (or components) responsible for this stimulatory effect is stable to heat (60 degrees C, 1 h) and mild trypsinization. Repeated addition of venom (1 microgram/ml) to pituitary cells in a perifusion column system demonstrated attenuation of GH release. This reduced response was not due to depletion of the GH pool since the pituitary cells were subsequently able to respond to both GH-releasing factor (GRF) stimulation and KCl depolarization. Somatostatin in a dose which abolished GRF-stimulated GH release failed to affect venom-stimulated GH release, implying that venom acts in a cyclic AMP-independent manner. We conclude that Burmese Russell's viper venom has direct effects on pituitary hormone release in vitro. Whether these effects contribute to its known actions in vivo on the function of the pituitary remains to be established.

Adrenocorticotropic Hormone↗
PubMed1988

Inappropriate ACTH concentrations in two patients with functioning adrenocortical carcinoma.

Two female patients with functioning adrenocortical carcinomas had plasma ACTH detectable by RIA at presentation. In both patients there was evidence for biological activity of ACTH. There was no evidence for an ectopic source of ACTH, nor for a pituitary tumour. Urinary steroid analysis showed patterns of multiple hormone secretion characteristic of adrenocortical carcinomas. The finding of detectable ACTH concentrations in a patient with Cushing's syndrome does not exclude the presence of an adrenocortical tumour.

Adrenal Gland Neoplasms↗
PubMed1988

The role of a highly sensitive amplified enzyme immunoassay for thyrotrophin in the evaluation of thyrotroph function in hypopituitary patients.

Using a highly sensitive amplified enzyme-linked immunoassay (AEIA) for thyrotrophin (TSH), we have assessed the ability of a single basal measurement of TSH to predict the subsequent response of TSH to TRH in a group of 11 patients with known pituitary pathology and some evidence of hypopituitarism. All patients were clinically euthyroid. Basal levels of AEIA-TSH ranged from less than 0.2 mU/l ('undetectable') to 0.9 mU/l; within this range there was no correlation with the subsequent TSH levels at 30 min in the TRH test. The TSH response in the TRH test did not correlate with the direct measurements of prevailing thyroid hormone levels (Total T4 or Free T4). We suggest that in patients with pituitary disease, the formal TRH test yields additional information regarding residual thyrotroph function that cannot reliably be predicted by a single basal TSH value, even when measured by a sensitive method. The current and potential thyroid status in patients with hypopituitarism must continue to rest on the overall picture provided by clinical assessment, direct measurement of thyroid hormones and the TRH test response. A basal TSH alone gives little useful information regarding thyroid status in such patients.

Adult↗
PubMed1988

Effect of nivazol in Nelson's syndrome.

We report the use of nivazol in a patient with Nelson's syndrome. Nivazol was highly effective in reducing ACTH secretion but, contrary to reports of its use in other primates, in our patient nivazol did have systemic glucocorticoid effects.

Adrenocorticotropic Hormone↗
PubMed1988

Retinal pigment epithelial change and partial lipodystrophy.

Cuticular drusen and retinal pigment epithelial changes were found incidentally in a 27 year old Lebanese woman during assessment of partial lipodystrophy. Her vision was normal despite involvement of both maculae. The patient had hypocomplementaemia, but serum C3 nephritic factor was absent and renal function was normal. She had impaired glucose tolerance and a continuous infusion of glucose with model assessment (CIGMA) test revealed low normal tissue insulin sensitivity and high normal pancreatic beta cell function. Mild fasting hypertriglyceridaemia (2.0 mmol/l) may have been secondary to impaired insulin sensitivity. Endocrine function was otherwise normal apart from a completely absent growth hormone response to adequate hypoglycaemia. The simultaneous occurrence of partial lipodystrophy and retinal pigmentary epithelial and basement membrane changes appears to be a newly recognized syndrome.

Adult↗
PubMed1988

Incidentally found small pituitary adenomas may have no effect on fertility.

Histological examination of the pituitary glands from 486 unselected autopsies revealed 97 clinically unsuspected adenomas in 78 glands (16%). Prolactinomas numbered 48; no hormone was found in 30, LH in 8, ACTH in 7, growth hormone (GH) and prolactin in 3, and GH alone in 1. Eleven of 194 female subjects and 37 out of 292 males had one or more prolactinoma. Clinical case notes, available for 57 of 78 subjects with adenomas, were reviewed to obtain data on fertility. Of the 25 women with case notes, 6 of the 11 with prolactinomas and 11 of the 14 with adenomas of other types had conceived. For the 32 males, 10 of the 23 with prolactinomas and 5 of the 9 with other types had procreated. These findings show that pituitary tumours not identified in life may have no major anti-fertility effect, and suggest that treatment of small intrasellar lesions discovered clinically by chance may not be necessary.

Adenoma↗