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Biomedical subjects

E H Cameron

Publications and source records attributed to E H Cameron.

At least 19 recordsLinked to original sources
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

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↗
PubMed1978

Comparison of plasma hormone changes using a "conventional" and a "paper" pill formulation of a low-dose oral contraceptive.

Two formulations of a low-dose oral contraceptive (Microgynon: 150 microgram of levonorgestrel [NG] +30 micrograms of ethynylestradiol [EE2]) were studied. The first was the "conventional" pill; the second was a "paper" pill prepared by evaporation of aliquots of a solution of the component steroids onto squares of edible cellulose separated by perforations, similar to a sheet of postage stamps. The effects of the two formulations on plasma levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17beta-estradiol (E2), and progesterone were compared. Samples of blood were obtained from five women during a treatment period on the "conventional" pill and from five on the "paper" pill. When possible, blood samples were also obtained from a "control" cycle of each of these female subjects. Plasma LH, FSH, E2, and progesterone levels were determined by specific radioimmunoassay methods during control and treatment periods and NG and EE2 levels during treatment periods. Eight-hour plasma profiles for NG and EE2 at the beginning and in the later stage of the treatment periods were obtained and these samples were also analyzed for LH, FSH, E2, and progesterone. Results showed that with one exceptcrogynon were equally effective in suppressing ovulation. As in a previous study, FSH levels appeared to be one of the most sensitive indices of suppression.

Adult↗
PubMed1978

Serum prolactin, gonadotrophin and oestrogen levels in women receiving hormone replacement therapy.

Prolactin, oestrone, oestradiol, FSH and LH concentrations have been determined in postmenopausal women receiving different forms of hormone replacement therapy. While the serum oestrogen levels achieved were sufficient to cause a significant decrease in circulating FSH and LH levels, no significant change in prolactin concentrations was found. Two other findings are of interest: despite the absolute concentrations achieved, the ratio of FSH to LH and the ratio of oestradiol to oestrone did not change significantly on any of the hormone formulations used; and while FSH and LH were both suppressed to a significant degree on therapy neither was suppressed to premenopausal values suggesting the possibility of a 'female inhibin' in the normal regulation of gonadotrophin secretion.

Estrogens↗
PubMed1977

Prevalence of severe growth hormone deficiency.

Four hundred and forty-nine short children, who were all over 2-5 standard deviations below the mean height for age, were identified by screening the heights of 48 221 6- to 9-year-old children in three Scottish cities. Most were screened for growth hormone deficiency (GHD). The prevalence of severe GHD in this sample may have been as high as 1 in 4018, much higher than reported. The findings suggest that present referral patterns may account for the delayed or missed diagnosis of the condition in girls or children with less severe short stature.

Body Height↗
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↗
PubMed1977

The effect of dialysate calcium concentration on 1alpha-hydroxyvitamin D3 on skeletal calcium loss and hyperparathyroidism in haemodialysis patients.

The response of hyperparathyroidism and skeletal calcium loss in haemodialysis patients to treatment with 1alpha-hydroxyvitamin D3 and a dialysate calcium concentration of 1.375 mmol/l was compared with the response to treatment with a dialysate calcium concentration of 1.375 or 1.75 mmol/l alone over a 6 month period. In patients treated with 1alpha-hydroxyvitamin D3 there was a significant rise in plasma calcium associated with a significant fall in plasma alkaline phosphatase and plasma parathyroid hormone as well as resolution of sub-periosteal erosions. In these patients there was a significant rise in the calcium content of the forearm assessed by neutron activation analysis in comparison to patients treated with a dialysate calcium concentration of 1.75 or 1.375 mmol/l alone. In patients treated with a dialysate calcium concentration of 1.375 or 1.75 mmol/l alone there was no significant change in the plasma calcium, alkaline phosphatase or parathyroid hormone after 6 months and in these patients subperiosteal erosions either did not change or became worse. No significant difference in the response in these two groups was observed. This study indicates that treatment of haemodialysis patients with 1alpha-hydroxyvitamin D3 is significantly more effective than treatment with a dialysate calcium concentration of 1.375 or 1.75 mmol/l alone in preventing progression of hyperparathyroidism and skeletal calcium loss.

Adult↗
PubMed1977

Failure of luteinizing hormone-releasing hormone and insulin to further augment thyrotrophin release in primary hypothyroidism.

The effect of luteinizing hormone-releasing hormone (LH-RH) and insulin-induced hypoglycaemia on the release of thyrotrophin (TSH) was studied in five patients with primary hypothyroidism. All five patients had elevated TSH levels with an exaggerated rise in response to thyrotrophin-releasing hormone (TRH). No rise over control values was found after LH-RH or insulin indicating that despite the augmentation of TSH release in primary hypothyroidism there is no alteration of the specificity of the thyrotroph response.

Adult↗
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↗
PubMed1976

Hypothalamic/pituitary/adrenal function in patients treated with intermittent high-dose prednisolone and cytotoxic chemotherapy.

Hypothalamic/pituitary/adrenal (H.P.A.) function was assessed in ten patients receiving intermittent high-dose prednisolone and cytotoxic chemotherapy for myeloma of lymphoma in order to predict their possible requirement for additional steroid therapy between and at the end of treatment courses. Standard insulin hypoglycaemia tests performed 36 hours after the last dose of prednisolone often demonstrated impairment of corticotrophin (adrenocorticotrophic hormone, A.C.T.H.) and growth-hormone responses, indicating hypothalamic/pituitary suppression; plasma-corticosteroid responses to endogenous A.C.T.H. and tetracosactrin were abnormal in two patients, indicating secondary adrenal suppression. Such hypothalamic/pituitary and adrenal suppression may make these patients susceptible to acute adrenal insufficiency in times of stress. H.P.A. function should be fully assessed on completion of chemotherapy.

Adrenal Cortex Hormones↗
PubMed1976

Studies on low-dose oral contraceptives: cervical mucus and plasma hormone changes in relation to circulating D-norgestrel and 17alpha ethynyl-estradiol concentrations.

A study was undertaken to determine the effects of a low-dose oral contraceptive comprising 150 mug of D-norgestrel and 30 mug of 17alpha-ethynyl estradiol (Microgynon) on the plasma levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17BETA-ESTRADIOL, AND PROGESTERONE AND ON THE PHYSICAl properties of cervical mucus. Samples of blood and cervical mucus were obtained from three women during a treated cycle and the immediately-following "withdrawal" cycle. Specific radioimmunoassay methods were used to determine LH, FSH, 17beta-estradiol, and progesterone levels in treated and withdrawal cycles, and D-norgestrel and 17alpha-ethynyl estradiol in samples obtained during treated cycles. The concentration of synthetic steroids was also measured in blood samples obtained before and 1 hour after ingestion of the contraceptive to determine the maximal daily variation. The results indicated that the contraceptive action of this combined low-dose oral contraceptive is mediated through suppression of ovulation and by rendering the cervical mucus impenetrable to sperm. Plasma FSH levels appeared to be one of the most sensitive indices of suppression. Determination of D-norgestrel and 17alpha-ethynyl estradiol showed that 3 to 4 days were required to reach maximal plasma levels and that daily fluctuations were considerable. Withdrawal of the pill resulted in an immediate return to ovulatory cycles in all three subjects studied.

Biological Clocks↗
PubMed1976

Plasma hormone levels and the incidence of carcinogen-induced mammary tumours in two strains of rat.

The incidence of mammary tumours developing after administration of the carcinogen DMBA (at 50 days of age) has been determined in 2 strains of Sprague-Dawley rat. Untreated animals of each strain were exsanguinated in dioestrus at a time corresponding to the early post-carcinogen stage (at 70 days of age) and the plasma concentrations of prolactin, oestradiol-17B and progesterone were measured by radioimmunoassay. In an inbred strain of rats, tumour-induction rate was 6-4% and plasma prolactin concentration was 2-5 x lower than that found in a random-bred strain with a tumour-induction rate of 41-6%. No difference was found between the 2 strains in the level of either ovarian hormone. It is concluded that the difference between these strains in mammary gland susceptibility to DMBA may be related to plasma prolactin concentration, but it is unlikely to be determined by the ovarian hormones.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1976

Propranolol in the treatment of thyrotoxicosis by subtotal thyroidectomy.

Subtotal thyroidectomy was performed in 40 patients with thyrotoxicosis in whom propranolol alone was used as preparation for surgery. Propranolol was given orally in a dose of 40 mg every 6 h for a mean preoperative period of 17 days (range 4-60 days) and continued for seven days after operation. The mean +/- SE blood loss at operation was only 160 +/- 20 ml. The period of follow-up was from three to nine months. Recurrent thyrotoxicosis has not occurred in any patient. Low levels of total serum triiodothyronine (T3) and total serum thyroxine (T4) were observed in the early postoperative weeks in some patients and were associated with symptoms of mild hypothyroidism, but by six months in the presence of a raised serum thyrotropin (TSH) the thyroid hormone levels returned to normal. Permanent hypothyroidism developed in only two patients. Despite normal or low total serum T3 and T4 levels, the TSH response to thyrotropin-releasing hormone (TRH) was absent in all patients one week after operation. At four weeks and at eight weeks, the response was absent or sub-normal in 70% and 20% of the patients respectively, indicating a delay in the recovery of the hypothalamo-pituitary axis previously exposed to high levels of T3 and T4. It is considered that subtotal thyroidectomy for thyrotoxicosis in patients prepared with propranolol is an acceptable procedure which has some advantages over the conventional preparation with carbimazole and potassium iodide, not the least of which are the potential reduction in preparation time, the more flexible timing of operation, and the reduced operative blood loss.

Female↗
PubMed1976

Measurement of cortisol, cortisone, 11-deoxycortisol and corticosterone in foetal sheep plasma during the perinatal period.

A method is described for the resolution and individual quantitation of cortisol, cortisone, 11-deoxycortisol and corticosterone in foetal sheep plasma. The steroids were extracted by solvent partition and separated by LH-20 Sephadex column chromatography. Radioimmunoassay was used for the measurement of 11-deoxycortisol and cortisone and competitive protein-binding for corticosterone and cortisol. The relative levels of these steroids in the plasma of chronically catheterized sheep foetuses from 12 days before birth to term and then in the newborn lamb until 2 days of age are recorded. Cortisol gradually increased from a basal concentration of between 0 - 5 and 3 - 0 mug/100 ml plasma between days 12 and 5 pre partum, and then rose rapidly to 10 mug/100 ml plasma during the last 5 days of pregnancy to reach a maximum during or just after birth. Two days post partum the levels had fallen to approximately 3 mug/100 ml plasma. The mean value for 11-deoxycortisol between days 8 and 3 pre partum was 0 - 4 mug/100 ml plasma and increased in the final days before delivery to 1 - 0 mug/100 ml. Corticosterone initially showed slightly higher levels (approximately 1 - 5 mug/100 ml) in the earlier period of investigation but then fell during the immediate pre-partum period to 0 - 8 mug/100 ml. Cortisone was not detected at any stage of the investigations. The relationship between levels of cortisol and 11-deoxycortisol in foetal plasma and myometrial contractility is shown. An increase in uterine activity was seen to occur at the time that cortisol levels were at their maximum. The 11-deoxycortisol values throughout this particular study remained low. The results are discussed in relation to recorded levels in the adult and to previous studies in vitro with regard to changing steroid biosynthetic enzyme activity.

Animals↗
PubMed1975

Thyroid function in the long-term follow-up of patients treated with iodine-131 for thyrotoxicosis.

In February, 1972, 58% of patients euthyroid after iodine-131 therapy for thyrotoxicosis between 1954 and 1966 had a raised plasma thyroid-stimulating-hormone (T.S.H.) (greater than 7-4 mU/l) and 42% a normal T.S.H. level. A group of 69 of the euthyroid patients with a raised plasma T.S.H. (25-0 +/- 2-0 mU/l) in 1972 was re-examined annually for three years. There was no apparent change in the mean plasma T.S.H. level between 1972 and 1975 in the patients remaining euthyroid, but overt hypothyroidism developed in 3 patients in 1973, in a further 3 patients in 1974, and in 1 patient in 1975. In contrast, none of a group of 61 patients, euthyroid with a normal plasma T.S.H. (4-0 +/- 0-2 mU/l) in 1972, developed overt hypothyroidism over the next three years, although slightly raised T.S.H. levels were recorded in 3 patients in 1974 and in a further 6 patients in 1975. Both the mean serum T-4 and T-3 in the euthyroid patients with a raised plasma T.S.H. were significantly lower, but still in the respective normal ranges, than those in the euthyroid patients with a normal plasma T.S.H. No significant difference in the fasting serum-cholesterol or triglyceride levels could be demonstrated between the two groups. Since no patient with a normal plasma T.S.H. after iodine-131 treatment for thyrotoxicosis six to eighteen years earlier developed overt hypothyroidism over a three-year period, the follow-up of such patients need not be so frequent as that of similarly treated euthyroid patients with a raised plasma T.S.H. in whom overt hypothyroidism develops at the rate of 2-5% per year.

Cholesterol↗