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Biomedical subjects

J Seth

Publications and source records attributed to J Seth.

At least 73 records · Page 4Linked to original sources
PubMed1983

Thyroid status in patients with chronic renal failure.

Serum thyroid hormone concentrations have been measured in 21 patients with chronic renal failure, treated conservatively and compared with values from 19 control subjects. Many patients had serum total T3 and T4 concentrations below the reference ranges. The concentrations of free T4 and free T3 and the free thyroxine index were significantly lower in patients with abnormal total concentrations of the thyroid hormones than in the controls. Both the free and the total concentrations of T4 correlated inversely with the degree of renal failure. The concentration of thyroxine binding globulin (TBG), fell within the reference range in each of the patients, but was significantly lower in the patient group when compared with the controls. These TBG concentrations, however, were not sufficiently decreased to explain the low total thyroid hormone concentrations found in the patients. The affinity of TBG for T4 and T3 in the patient and control groups was not significantly different. The TSH response to TRH was diminished in many of the patients, but the measurement of other pituitary hormones indicated that pituitary function was normal in these patients. The possible mechanisms responsible for the changes observed in thyroid and pituitary hormones are discussed.

Adolescent↗
PubMed1982

Does calcitonin cause hypocalcaemia after thyroidectomy?

Plasma calcitonin, parathyroid hormone, total thyroid hormones and calcium were measured in 6 patients before, during and after thyroidectomy for hyperthyroidism. In 4 patients, plasma calcium fell postoperatively by 0.23--0.46 mmol/l, but there was no change in calcitonin or parathyroid hormone levels. In one patient, in whom there was a postoperative fall in plasma calcium of 0.55 mmol/l, thyroid hormones rose to a peak at 1 h and calcitonin to a peak at 12 h after resection. However, the rise in calcitonin occurred 8 h after the initial decrease in plasma calcium. In this patient, parathyroid hormone levels showed a slight rise only. It is concluded that, while thyroid hormones and calcitonin may leak from the damaged thyroid remnant after surgery, it is unlikely that calcitonin is important in the production of postoperative hypocalcaemia. However, impaired parathyroid hormone secretion may be a contributing factor.

Adolescent↗
PubMed1982

The effect of ethinyl estradiol 20 mcg and levonorgestrel 250 mcg on the pituitary-ovarian function during normal tablet-taking and when tablets are missed.

A new combined pill containing 20 micrograms of ethinyl estradiol and 250 micrograms of levonorgestrel has been developed. The safety margin of this type of low-dose preparation needed to be assessed and this was done by evaluating daily levels of LH, FSH, estradiol, progesterone, 1-NG and EE2 as well as cervical mucus characteristics in six patients when one and then two consecutive pills were deliberately omitted mid-way through the cycle. Results demonstrated that there was no evidence of breakthrough ovulation, although there was some continued ovarian steroidogenesis, a feature consistent with previous studies using combined preparations. Existing instructions to patients regarding missed pills should continue in order to ensure maximal contraceptive safety.

Adolescent↗
PubMed1982

Is testicular endocrine function abnormal in young men with spinal cord injuries?

Plasma concentrations of FSH, LH, testosterone and prolactin have been studied in seventeen men, aged 19 to 38 years, with traumatic paraplegia. Plasma testosterone, FSH and LH values were normal in all patients. The median LH concentration in patients was significantly higher (P less than 0.05) than in controls but there was no difference for FSH or testosterone. Plasma prolactin was high in five patients and the median prolactin concentration in patients was significantly greater (P less than 0.001) than in controls. It is concluded that there is no evidence of primary testicular failure in young paraplegics but it is possible that testicular hypofunction in some paraplegics may be related to increased prolactin production.

Adult↗
PubMed1982

What is the significance of raised plasma TSH levels after thyroid surgery?

Thyroid function was assessed prospectively for five years in 73 patients treated surgically for Graves's disease. No patient developed hypothyroidism after the sixth postoperative month, despite the presence of raised plasma TSH levels in 70 per cent of euthyroid patients at the end of the first year. Indeed, in those with evidence of temporary hypothyroidism (low T4, raised TSh at 3 months but normalisation of T4 at 6 months) plasma TSH continued to fall for up to three years. The majority (6) of patients developing recurrent hyperthyroidism did so within the first year, but in one of three patients who relapsed subsequently, plasma TSH had been elevated at one year. Plasma TSH cannot be used to predict thyroid status following surgery for Graves' disease. Although regular review remains necessary, it should not include measurement of TSH unless this is needed to confirm the validity of a low thyroxine level after the third postoperative month and before starting permanent replacement therapy.

Adult↗
PubMed1982

Prolactin response to metoclopramide in hyperthyroidism.

The response of PRL to the oral administration of the dopamine receptor-blocking agent metoclopramide and the effect of metoclopramide on the TRH-induced release of PRL and TSH were measured in eight patients with hyperthyroidism and in eight age- and sex-matched euthyroid controls. As expected from the known direct inhibitory influence of thyroid hormones on pituitary TSH secretion, there was no TSH rise in response to metoclopramide in either group. PRL levels, on the other hand, rose significantly after the administration of metoclopramide in both the hyperthyroid and euthyroid subjects (P less than 0.0005 at 60 and 120 min). However, the increase in PRL at 120 min was significantly less in the hyperthyroid subjects than in the euthyroid controls (P less than 0.0025). Furthermore, the administration of metoclopramide failed to reestablish normal responsiveness of either PRL or TSH to TRH in the hyperthyroid subjects. We have previously suggested that thyroid hormones inhibit PRL secretion by stimulating the hypothalamic secretion of dopamine. These results suggest, however, that elevated levels of thyroid hormones also inhibit PRL release directly at the anterior pituitary level.

Administration, Oral↗
PubMed1982

Some risk factors associated with cataract in S.E. Scotland: a pilot study.

Problems of epidemiological studies of cataract are outlined. Some results are reported from a study on 931 cataract patients and 325 non-cataractous individuals. After correction by age and sex several single variables were found to have significant positive or negative correlations with cataract. Interactions between variables were found; these include age, diabetes, the use of diuretics and cataract, between age, sex, the level of alcohol consumption and cataract, and between age, sex, plasma urea levels and the use of different diuretic drugs, only some of which were found to have a positive association with cataract.

Aged↗
PubMed1981

Patterns of plasma cortisol and ACTH concentrations in patients with Addison's disease treated with conventional corticosteroid replacement.

Plasma cortisol and adrenocorticotrophin hormone (ACTH) profiles were estimated in twelve patients with Addison's disease following randomized oral administration of either cortisone acetate (25 mg) or hydrocortisone (20 mg) alternately, at 0900 h on consecutive days. Normal corticosteroid replacement therapy was discontinued from 1200 h on the day prior to the study period. In four patients elevated basal plasma ACTH concentrations were not suppressed to the limit of detection following the administration of either drug, and in three of these no suppression was found following the prolonged administration of pharmacological doses of dexamethasone. Diminished sensitivity of pituitary ACTH secretion to cortisol inhibition may result from chronic loss of negative feedback before and/or after diagnosis and treatment. In three patients elevated basal plasma ACTH concentrations were suppressed adequately during the administration of either drug, but in five, low basal ACTH concentrations following corticosteroid withdrawal suggested chronic inhibition of anterior pituitary corticotrophs by over-replacement with glucocorticoid. However, further study is necessary to determine whether the estimation of ACTH profiles is a more accurate reflection of the adequacy of corticosteroid replacement than the estimation of cortisol profiles alone, and whether this estimation leads to an improvement in patient management. Hydrocortisone (20 mg) achieved higher mean cortisol levels and lower mean ACTH levels than cortisone acetate (25 mg), but either drug may be suitable for glucocorticoid replacement provided the dose is tailored to the individual needs.

Addison Disease↗
PubMed1980

Transient hypothyroidism after iodine-131 treatment of thyrotoxicosis.

Thirty consecutive patients with thyrotoxicosis were followed up at monthly intervals for 6 months after treatment with iodine-131. Serum total T4, serum total T3, and serum TSH response to TRH were measured at each review. Biochemical evidence of hypothyroidism (low T4 raised basal TSH) developed in 18 patients 1-4 months after treatment. In 5 of these patients, symptoms and signs of hypothyroidism remained absent or minimal and spontaneous recovery of thyroid function occurred during the ensuing 2 months. If biochemical hypothyroidism occurs during the first 6 months after radioiodine therapy, it is recommended that T4 replacement be withheld for 2 months unless the severity of symptoms demands treatment.

Adult↗
PubMed1980

Prevalence of subclinical thyroid failure in insulin-dependent diabetes.

A study was made of the distribution of primary thyroid failure, indicated by a raised serum TSH concentration, in 605 (294 males and 311 females) insulin-dependent (type I) diabetics, aged 21-84 yr, not previously suspected of having thyroid disease. The prevalence of a raised serum TSH concentration in females of all ages (17%) was significantly greater (P less than 0.0005) than that in males (6.1%) and increased with increasing age at onset of diabetes (P less than 0.05) and age at time of study (P less than 0.001) in females but not in males. There was no significant difference in the duration of diabetes when comparing patients with normal and raised serum TSH concentrations. The prevalence of a raised TSH concentration in late-onset insulin-dependent diabetics was no greater in patients requiring insulin within 3 months of diagnosis of diabetes than in those exhibiting secondary sulfonylurea failure, who required insulin more than 3 months after diagnosis. In type I diabetes, the prevalence of subclinical primary thyroid failure is considerably greater than has previously been suspected, with female late-onset insulin-dependent diabetics being at the greatest risk.

Adult↗
PubMed1980

Influence of thyroid status on dopaminergic inhibition of thyrotropin and prolactin secretion: evidence for an additional feedback mechanism in the control of thyroid hormone secretion.

Serum TSH and PRL concentrations were measured after the randomized oral administration of either metoclopramide, L-dopa, or placebo on 3 consecutive days to five patients with overt primary hypothyroidism (low serum total T4 and raised serum TSH) and to five patients with subclinical hypothyroidism (normal serum total T4 and raised serum TSH). In both groups there was a rise in serum TSH and PRL concentrations after metoclopramide and a fall after L-dopa when compared with the effect of the placebo. However, the rise in serum TSH and PRL concentrations was significantly greater in patients with subclinical hypothyroidism compared to that in patients with overt hypothyroidism. It was not possible to show any significant difference in the degree of fall of these pituitary hormones after L-dopa administration in the two groups. These results suggest that in addition to the established negative feedback of thyroid hormones at the level of anterior pituitary thyrotropes, there is a previously unrecognized effect of thyroid hormones at the hypothalamus, resulting in increased dopaminergic inhibition of TSH release. Stimulation of hypothalamic dopamine by thyroid hormones also inhibits PRL secretion.

Feedback↗
PubMed1979

Failure of the TRH test to predict the clinical course of patients in remission after antithyroid drug therapy for Graves' disease.

In an attempt to assess the predictive value of the TRH test in patients in remission after stopping antithyroid drugs for thyrotoxicosis, 11 euthyroid patients with a subnormal (group I) and 23 euthyroid patients with a normal serum TSH response to TRH (group II) were followed-up for one year. The mean +/- SE intervals since the withdrawal of drug therapy were 23.2 +/- 1.6 and 20.4 +/- 0.7 months, respectively, at the outset of the study. Five patients (45%) from group I and 7 patients (30%) from group II relapsed during the period of observation. In addition, a change from a subnormal TSH response to TRH and vice versa occurred in some patients. It is not possible to predict by means of the TRH test the subsequent clinical course of patients in remission following antithyroid drug therapy.

Adult↗
PubMed1978

How often should patients be reviewed after treatment with iodine-131 for thyrotoxicosis?

Six to 18 years after treatment with iodine-131 for thyrotoxicosis 69 euthyroid patients with raised serum thyrotrophin (TSH) concentrations (mean 25.0 +/- SE 2.0 mU/l) and 61 with normal concentrations (mean 4.0 +/- 0.2 mU/l) were included in a prospective five-year follow-up study beginning in 1972. During this period 13 patients from the original group with raised serum TSH concentrations became hypothyroid. In contrast it was five years before hypothyroidism developed in a single patient from the group with normal serum TSH concentrations in 1972, although raised concentrations were recorded in 19 of these patients during the study.

Aged↗
PubMed1978

A simple radioimmunoassay for plasma cortisol.

A simple radioimmunoassay (RIA) for plasma cortisol is described which combines the advantages of (i) direct analysis of untreated plasma samples, (ii) use of solid-coupled anti-cortisol antibodies and (iii) use of a gamma-labelled radioligand. The reagents are relatively easily prepared and stable, and the analysis can be completed in 4 h. Inter-assay precision (C.V.) is 8-11%. Critical examination of specificity using high pressure liquid chromatography showed that 23-35% of the immunoassayable material in plasma was not cortisol. RIA results on samples collected under basal conditions were on average 40 nmol/l lower than fluorimetric results, while in insulin hypoglycaemia and synacthen (ACTH) stimulation tests, this difference increased to over 100 nmol/l. The RIA is technically more simple than fluorimetric, competitive-protein-binding, and many RIA methods, and can be used with advantage in the routine investigation of adrenocortical function. However, using the present antiserum, the RIA is not applicable to investigations on patients receiving metyrapone, nor in suspected cases of congenital adrenal hyperplasia.

Animals↗
PubMed1978

Thyroid function after surgical treatment of thyrotoxicosis. A report of 100 cases treated with propranolol before operation.

We assessed thyroid function for 12 months after subtotal thyroidectomy in 100 tyrotoxic patients treated with propranolol alone before and immediately after operation. The operation proved safe, with low morbidity. Suppression of the hypothalamic-pituitary-thyroid axis, present in the majority one month after operation, was evidenced by normal or low levels of serum total tri-iodothyronine and thyroxine, but absent or subnormal serum thyrotropin response to thyrotropin-releasing hormone. Eighty patients were euthyroid at 12 months. Three patterns of thyroid function were observed in this group between the first and 12th months: normal serum total tri-iodothyronine, thyroxine and thyrotropin levels at all stages (20 patients); normal serum total tri-iodothyronine and thyroxine, but raised thyrotropin levels on one or more occasions (40 patients); and temporary hypothyroidism (20 patients). Of the remaining 20 patients, permanent hypothyroidism developed in 14, and six relapsed. Postoperative thyroid function was related to the estimated weight of the thyroid remnant.

Adult↗
PubMed1977

Spectrum of thyroid function in patient's remaining in remission after antithyroid drug therapy for thyrotoxicosis.

Thyroid function was assessed in 110 patients who were in remission for a period of 7-6 +/- 0-6 years (mean +/- S.E.) (range 0-25--25 years) after the withdrawal of antithyroid drug therapy for thyrotoxicosis. On the basis of clinical examination and on the results of thyroid-function tests, the following group of patients were identified: (I) euthyroid with normal plasma-total thyroxine (T4) and triiodothyronine (T3) concentrations, but an absent or subnormal response of plasma-thyrotrophin (T.S.H.) to thyrotrophin-releasing hormone (T.R.H.) (16%); (II) euthyroid with normal concentrations of plasma total T4 and T3 and a normal plasma-T.S.H. response to T.R.H. (59%); (III) euthyroid with normal concentrations of circulating thyroid hormones and a normal basal plasma-T.S.H., but an exaggerated plasma-T.S.H. response to T.R.H. (13%); (IV) euthyroid with normal plasma total T4 and T3 concentrations, but a raised basal plasma-T.S.H. concentration and an exaggerated plasma-T.S.H. response to T.R.H. (6%); (V) hypothyroid (6%). Although the need for short-term follow-up to identify those patients treated with antithyroid drugs who will relapse is well recognised, 16% of all patients in remission for longer than 4 years (10-8 +/- 0-7 years) in the present study showed some degree of thyroid failure. Evidence of hypothyroidism was associated with an increased frequency of thyroid microsomal antibodies. If the morbidity of the late development of hypothyroidism is to be avoided, patients who have been treated with antithyroid drugs should have long-term follow-up, as do patients treated surgically or with radioiodine.

Antithyroid Agents↗
PubMed1976

Temporary hypothyroidism after surgical treatment of thyrotoxicosis.

Mild clinical hypothyroidism associated with low levels of serum total thyroxine (T4) and tri-iodothyronine (T3) and raised levels of serum thyroid-stimulating hormone (T.S.H.) has been observed in 14 of 40 patients (35%) in the early months after a subtotal thyroidectomy for thyrotoxicosis under cover of propranolol. In 10 of the patients, however, the hypothyroidism was temporary and at 6 months after operation the thyroid hormone levels were normal and the serum T.S.H. levels had fallen. In 4 of the patients in whom clinical and biochemical evidence of hypothyroidism persisted 6 months postoperatively, long-term T4 replacement therapy was instituted. It is concluded that the diagnosis of permanent hypothyroidism should not be made with confidence before 6 months have elapsed after operation and that the incidence of hypothyroidism following the surgical treatment of thyrotoxicosis may have been overestimated in the past.

Adult↗