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Biomedical subjects

W J Kalk

Publications and source records attributed to W J Kalk.

At least 55 records · Page 3Linked to original sources
PubMed1986

Fatty acid induced changes in circulating total and free thyroid hormones: in vivo effects and methodological artefacts.

Elevated levels of nonesterified fatty acids (NEFA) are frequently found in acute illnesses, and they may contribute to changes in serum thyroid hormone concentrations in nonthyroidal illnesses (NTI) by displacing protein bound hormones. We therefore examined the effects of low and raised plasma NEFA levels on circulating total and free thyroxine (TT4 and FT4) and triiodothyronine (TT3 and FT3) concentrations, the Free T4 Index (FT4I) and TSH, in a randomized crossover study in 10 normal subjects. Subjects ate either a high carbohydrate breakfast (low NEFA protocol) or a high fat breakfast followed by an iv injection of 1000 u heparin (high NEFA protocol). Possible biological effects of changes in FT4 and FT3 were evaluated by a 200 micrograms iv TRH test. Free T4 and T3 were measured by a direct analogue method (AFT4 and AFT3). In a similar high NEFA study, but without TRH, FT4 was also measured by equilibrium dialysis (DFT4) and a 2-step RIA method (2-step FT4). Acute elevations of plasma NEFA from 0.67 +/- 0.08 mmol/L to a peak of 2.6 +/- 0.54 mmol/L resulted in a prompt reciprocal fall of mean TT4 (-8.7%, p less than 0.01), AFT4 (-30%, p less than 0.005) and TT3 (-11.5%, p less than 0.01) and AFT3 (-16%, p less than 0.005); DFT4 rose significantly from 23.7 +/- 1.9 pmol/L to 33.0 +/- 3.7 pmol/L (+39%, p less than 0.025) and 2-step FT4 rose by 16% (p less than 0.05). TSH levels declined consistently from 3.3 +/- 0.5 mIU/L to 2.6 +/- 0.4 mIU/L (p less than 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Proteins↗
PubMed1986

Circulating thyroid hormones in primates with mild or severe hepatitis following liver transplantation.

In order to study the effects of acute immunologically mediated liver disease on circulating thyroid hormones, serum levels of thyroxine (T4, total and free) and triiodothyronine (T3) were measured in 8 baboons before and for 60 days after allogeneic liver transplantation. In 3 animals early rejection and jaundice developed; T4 levels declined as liver function deteriorated. In the 5 tolerant animals liver function was only temporarily deranged without jaundice and there was a consistent early rise in T4 (P less than 0.01) followed by a later fall. T3 concentrations were relatively normal in both groups. The T3 resin uptake test remained virtually unchanged in all animals. Serum T4 and T3 responses to exogenously administered bovine thyrotropin (TSH) were similar in the jaundiced and anicteric animals. We conclude that the early rise in T4 in the tolerant animals was caused by transient increases in thyroid binding globulin in (TBG) while the fall in thyroid hormones in these and in the jaundiced animals was related to a decline in TBG levels. Thyroid responsiveness to TSH is not disturbed by moderately deranged liver function.

Animals↗
PubMed1986

Thyroid hormone and carrier protein interrelationships in children recovering from kwashiorkor.

We have studied 15 infants with severe protein energy malnutrition (PEM) as a model of nutritional nonthyroidal illness. Changes in circulating thyroid hormones, binding proteins, and their interrelationships were assessed before and during recovery. Serum concentrations of total thyroxine and triiodothyronine and of thyroxine-binding proteins were extremely reduced, and increased progressively during 3 wk of refeeding. The T4:TBG molar ratio was initially 0.180 +/- 0.020, and increased progressively, parallel to the increases in TT4, to 0.344 +/- 0.038 after 21 days (p less than 0.025). The changes in free T4 estimates varied according to the methods used--FTI and analogue FT4 increased, dialysis FT4 fraction decreased. Serum TSH levels increased transiently during recovery. It is concluded 1) there is reduced binding of T4 and T3 to TBG in untreated PEM which takes 2-3 wk to recover; 2) there are methodological differences in evaluating free T4 levels in PEM; 3) increased TSH secretion appears to be an integral part of the recovery from PEM.

Carrier Proteins↗
PubMed1986

Parathyroid hypertension. A reversible disorder.

A retrospective study of 75 patients who were surgically cured of primary hyperparathyroidism from 1976 to 1984 was performed to evaluate the blood pressure and metabolic responses to parathyroid surgery. Published data on the population prevalence of hypertension (HT) in South Africa were used for comparison. The overall prevalence of HT before surgery was 47%, compared with 23% in the general population. Hypertension was most frequent in patients older than 60 years (62% vs 39% expected). Renal insufficiency was found in 13 of 35 hypertensive patients and in two of 40 normotensive patients. However, the prevalence of HT in patients with normal creatinine levels (37%) exceeded that expected. The frequency of urolithiasis and mean levels of serum and urine calcium and phosphate were similar in normotensive and hypertensive patients. Parathyroidectomy resulted in a substantial fall in both mean systolic and mean diastolic blood pressures in 54% of the hypertensive subjects, unrelated to improvement in renal function.

Blood Pressure↗
PubMed1985

Transplantation for diabetic nephropathy.

The results of renal transplantation for end-stage diabetic nephropathy in 17 patients--11 receiving cadaver (CD) grafts and 6 related living donor (RLD) grafts--are reported. The transplants were rejected in 5 cases, in 4 acutely, and these patients were returned to haemodialysis; 3 of them subsequently died. One patient died of heart failure, but the graft was still functioning. The remaining 11 patients enjoy good renal function. The outcome was superior to results on dialysis, particularly for RLD grafts, and was comparable to results of transplantation for non-diabetic renal failure. Visual acuity tended to stabilize or improve after transplantation, but peripheral vascular disease progressed. Blood glucose control was suboptimal and requires more attention. Lipoproteins did not differ from those in non-diabetic patients. Renal transplantation is feasible and probably the preferred method of treatment for end-stage diabetic nephropathy.

Adult↗
PubMed1985

Evaluation of a new blood glucose reflectance meter and comparison with visually interpreted strips.

The utility of a new glucose reflectance meter (the Reflolux; Boehringer Mannheim) and the accuracy of visually interpreted strips (Haemo-Glukotest 20-800R; Boehringer Mannheim) for the determination of blood glucose levels were assessed in a study of 50 insulin-dependent diabetics who regularly used the strips for home monitoring of their blood glucose levels. There was a highly significant correlation (r = 0,970, P less than 0,0001) between readings on the meter and results of a laboratory reference plasma glucose determination method. The patients' visual assessment of their blood glucose levels using the strips also correlated with the results of a reference method in 44 cases (88%), especially at levels below 11 mmol/l (r = 0,944, P less than 0,0001). However, readings from 6 patients were inaccurate, despite the fact that these patients regularly used the strips. A patient's ability to use the strips should be properly evaluated before it is recommended that they be used for monitoring of blood glucose levels at home. Reflectance meters are not usually necessary for satisfactory blood glucose monitoring at home. This meter may prove useful in training patients to read blood glucose assessment strips accurately, and is suitable for hospital or office use.

Blood Glucose↗
PubMed1985

Nifedipine does not impair the hormonal responses to graded exercise in healthy subjects.

The aim of this study was to assess whether the potent calcium antagonist nifedipine was capable of modifying the hormonal response to graded exercise in 7 healthy young men. After fasting overnight, each subject came to the laboratory on 2 consecutive mornings. On one day he was given 10 mg of nifedipine sublingually and on the other an identical placebo capsule; the order was randomised in a double-blind fashion over the 2 days. Thereafter each subject performed 2 successive short treadmill runs, equivalent to 60 and 100%, respectively, of maximal aerobic power. While significantly blunting the rise in mean systolic blood pressure and inducing a greater fall in diastolic blood pressure during and after exercise compared with the placebo, nifedipine did not impair the brisk response to pituitary-adrenal hormones (ACTH, cortisol and total catecholamines). Nifedipine also did not modify the effects of short-term exercise in raising mean plasma glucose levels, stimulating pancreatic glucagon secretion and producing a delayed increase in plasma insulin concentrations. Nor did the drug blunt the significant rise of growth hormone and prolactin levels occurring during and after the treadmill run. It was concluded that, apart from inducing significant changes in blood pressure, a single dose of nifedipine does not appear to suppress the counterregulatory hormonal responses to short-term physical activity in healthy men.

Adrenal Cortex Hormones↗
PubMed1984

The 8-hour metabolic profile after drinking ethanol.

The acute metabolic changes after drinking ethanol have been studied in 11 fasting, healthy, nonobese, medical students, 6 of whom consumed 40 g ethanol diluted with 750 ml of a sugar-free soft drink over 1 h. The other 5 drank the same volume of soft drink alone. Blood levels of ethanol, glucose, immunoreactive insulin and growth hormone were measured over the ensuing 8 h, as well as the plasma concentrations of prolactin, cortisol and triiodothyronine. After ingesting ethanol, the mean plasma glucose concentration declined, but not to hypoglycemic levels (the nadir was 3.9 mmol/l at 6 h), insulin levels fell gradually and the mean growth hormone concentration showed a modest late rise. Other hormones did not change significantly. We conclude that, in the particular setting examined, the oral administration of ethanol does not cause hypoglycemia or other adverse effects on carbohydrate metabolism.

Adult↗
PubMed1984

Circulating thyroid hormones in progressive renal failure in the baboon (Papio ursinus).

In order to examine the effects of developing renal failure on circulating thyroid hormones, serum concentrations of thyroxine (T4), free T4 (FT4), triiodothyronine (T3) and reverse T3 (rT3) and TBG capacity were measured in 9 baboons before and during the progress of acute (mean survival 12 days), subacute (32 days) and chronic (120 days) renal failure following allogeneic renal transplantation. Irrespective of the rate of development of renal failure, there were significant, non linear (power functions) negative correlations between serum creatinine or urea concentrations and levels of T4, FT4 and T3; rT3 levels remained unchanged, but the T4: rT3 molar ratio fell from 236.5 +/- 61 (+/- SE) to 121.8 +/- 30.9 (p less than 0.05). T4 and T3 levels were invariably subnormal at creatinine concentrations greater than 250 mumol/l (2.8 mg/dl), but FT4 was subnormal only in chronic renal failure. Thyroxine binding globulin (TBG) capacity did not change significantly; thus the TBG: T4 ratio increased from 3.4 +/- 0.2 (basal) to 10.4 +/- 3.4 before death (p less than 0.05). In animals which survived for greater than 25 days after transplantation, a significant linear correlation between FT4 and T3 was found as uremia progressed. Polyacrylamide gel electrophoresis (pH 7.4) of (125I)-T4 labelled preoperative and uremic serum showed a consistent decline in the proportion of tracer bound to TBG, from 67.0 +/- 0.8% to 58.9 +/- 1.0% (p less than 0.001), with a 48% reduction in TBG saturation (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1983

Frequency of euthyroid sick syndrome as assessed by free thyroxine index and a direct free thyroxine assay. A limitation of FT4 assays.

The frequency of the euthyroid sick syndrome (ESS) was assessed in 3444 hospital patients. For the first 6 months the free thyroxine index (FTI) was used: 3.6% of 1674 patients had ESS compared with 17.3% of 1770 in the second 6 months diagnosed by a direct free thyroxine (FT4) assay ("Amerlex'). The relative frequencies of each type of ESS (low triiodothyronine [T3] only, low T3 plus low FT4 or FTI, and high FT4 or FTI with normal or low T3) and the frequencies of hypothyroidism (high TSH) and hyperthyroidism (high FTI/FT4 and T3) were similar in both periods. In the FT4 period requests for T3 assays increased by 300%. Measurements of both FT4 and FTI in 46 patients with ESS confirmed that ESS is diagnosed more frequently with the FT4 assay: the distribution of normal and abnormal T3 and reverse T3 levels were similar in FT4 ESS and FTIESS. FT4 is labile in illness and thus direct FT4 measurements also fluctuate, not necessarily reflecting thyroid status.

Diagnosis, Differential↗
PubMed1983

Cutis verticis gyrata with metabolic abnormalities.

An adult Black South African man with forme fruste pachydermoperiostosis is described. The patient had cutis verticis gyrata, hyperhidrosis, sebaceous plugging and an acneform rash. Basal and dynamic endocrine studies revealed that the hypothalamic, pituitary, thyroid, adrenal, gonadal axes and growth hormone secretion were all normal, but urinary excretion of 17-hydroxy-and corticosteroids, and the prolactin response to thyrotropin-releasing hormone were depressed. Urinary levels of asparagine were markedly elevated and serum levels were subnormal indicating a possible renal leak of this amino acid; glutamic acid and ornithine were present in smaller quantities in the urine. All other tests of proximal and distal renal tubular function were normal. There is no evidence from our studies to suggest a hormonal basis for pachydermoperiostosis. The amino aciduria may be a chance association of, or an (additional) occasional manifestation of the syndrome.

Adult↗
PubMed1982

High radio-isotope uptakes in patients with hypothyroidism.

Hypothyroidism is usually associated with a low radio-isotope uptake by the thyroid gland. We report 8 cases of Hashimoto's thyroiditis with clinical and biochemical hypothyroidism and with borderline high or overtly increased technetium-99m pertechnetate and/or iodine-131 uptakes.

Adolescent↗
PubMed1982

Precocious puberty associated with craniopharyngioma.

Craniopharyngiomas in children are usually associated with growth retardation and hypogonadism. A patient with a craniopharyngioma treated with radiotherapy, who later developed isosexual precocious puberty, is described. She was treated with cyproterone acetate with a good clinical response. We suggest that craniopharyngiomas may become a more frequent cause of precocious puberty now that conservative therapy has been advocated for the condition.

Child, Preschool↗
PubMed1982

Diagnosis of acromegaly on cranial computed tomography.

The characteristic features of acromegaly as demonstrated on cranial computed tomography (CT) are described. These features relate to the increased soft tissue bulk and overpneumatization of sinuses and air cells, as well as the generalized bony overgrowth associated with high growth hormone (GH) levels. In the assessment of these features, the computer window settings must be adjusted accordingly for separate visualization of soft tissues, calvarial bones and cerebral tissue on the scan images. We found positive features in CT scans of 13 patients with established acromegaly and were able to suggest the diagnosis prospectively in 2 additional cases. The finding of an enlarged pituitary fossa should lead the radiologist to search carefully for the ancillary signs of acromegaly on the scans, thus confirming the diagnosis. When an enlarged sella turcica or an enhancing intrasellar mass is not demonstrated, the recognition of the other features on cranial CT scans may be important in suggesting the diagnosis of acromegaly to the clinician.

Acromegaly↗
PubMed1981

Yersinia arthritis mimicking acute rheumatic fever. A case report.

A reactive or post-infectious arthritis is a well-known complication of yersinia enterocolitica infection and tends to occur in patients with the HLA-B27 haplotype. We describe such a patient, who in addition satisfied the revised Jones criteria for a diagnosis of acute rheumatic fever. Our case illustrates that arthritis due to Yersinia may mimic acute rheumatic fever both clinically and serologically. In areas where Yersinia infection is known to occur, infection with this organism should be excluded in all patients who satisfy the revised Jones criteria.

Adult↗