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Biomedical subjects

T H Diamond

Publications and source records attributed to T H Diamond.

At least 19 recordsLinked to original sources
PubMed1992

Reproducibility of lateral spine scans using dual energy X-ray absorptiometry.

Reproducibility of lateral spine dual energy X-ray absorptiometry (LAT DEXA) scans using a Lunar DPX-L scanner was assessed in a cadaveric phantom and in patients. One hundred phantom measurements over 7 months demonstrated a longitudinal stability of 1.7% (coefficient of variation, CV). Additional scans were performed with the phantom rotated by up to 20 degrees in each of the three orthogonal planes to assess the effects of variable patient positioning. Horizontal and vertical rotation of the spine had little effect on the estimated bone mineral density (BMD), however, axial rotation of greater than 8 degrees led to errors in the BMD measurement. One hundred consecutive patients had two lateral scans performed within 1 month. BMD (range 0.10-1.6 g/cm2) was determined for each scan by one operator. Significant overlap from ribs and pelvis was often seen with L2 and L4 vertebrae but one vertebra (L3) could be measured in every case. Intraoperator and interoperator variability was assessed by three experienced operators, each analyzing 10 patients' scans on five separate occasions, and was found to be less than 1.1% for a single vertebra. BMD estimation of vertebral bodies and midslices by lateral DEXA scans (CV% of 3.8% and 4.6%) have a 95% confidence interval of 0.074 g/cm2 and 0.096 g/cm2, respectively for two vertebrae. This variability is due mainly to axial rotation, with operator variability, horizontal rotation, and vertical rotation having little effect on BMD estimation.

Absorptiometry, Photon↗
PubMed1990

The acute effects of glucosidase inhibition on post-meal glucose increments in insulin-dependent diabetics.

The effects of glucosidase inhibition on postprandial glucose tolerance was studied in 11 insulin-dependent diabetics. In comparison with placebo, 50 mg miglitol was able to lower the incremental glucose response significantly at 30 minutes and 60 minutes when insulin was injected: (i) 30 minutes before the meal (2,3 +/- 0,5 mmol/l v. 0,37 +/- 0,2 mmol/l; P less than 0,001; and 5,0 +/- 0,7 mmol/l v. 1,1 +/- 0,8 mmol/l; P less than 0,001); and (ii) immediately before the meal (2,3 +/- 0,5 mmol/l v. 2,2 +/- 0,9 mmol/l; P less than 0,001) respectively. The incremental glucose area under the curve when insulin was injected 30 minutes before breakfast was also significantly reduced on miglitol in comparison with placebo (0,67 +/- 0,15 mmol/l v. 0,16 +/- 0,14 mmol/l; P less than 0,01). The effect of miglitol was more evident when insulin was injected 30 minutes before rather than immediately before the meal. No significant adverse effects were encountered. It is concluded that: (i) miglitol safely reduces the early post-meal glucose increments in insulin-dependent diabetics; and (ii) its effect enhances the hypoglycaemic response of an appropriately timed injection of insulin.

1-Deoxynojirimycin↗
PubMed1989

Time-dependent changes in serum gastrin measurements after parathyroidectomy.

A prospective study involving 7 patients with primary hyperparathyroidism and hypergastrinaemia was conducted to assess the time-dependent change in serum gastrin value before and after parathyroidectomy and to determine at which postoperative stage persistent hypergastrinaemia may be indicative of an associated gastrinoma (Zollinger-Ellison syndrome). Five of the 7 patients had hypergastrinaemia in the early postoperative period. One patient had a strikingly high serum gastrin level pre-operatively (1,500 pg/ml). The mean serum gastrin value declined to within the normal range 6 weeks after parathyroidectomy, except in 1 patient who had a gastrinoma. It is concluded that hypergastrinaemia in patients with primary hyperparathyroidism should only be considered significant if pre-operative gastrin levels are strikingly supranormal and/or levels fail to normalise by the 6th postoperative week.

Adult↗
PubMed1989

Hepatic osteodystrophy. Static and dynamic bone histomorphometry and serum bone Gla-protein in 80 patients with chronic liver disease.

To study the pathogenesis of osteoporosis in patients with chronic liver disease, we performed dynamic bone histomorphometry and measured serum bone Gla-protein in 80 patients with various types of chronic liver disease. These results were compared with results obtained in 40 healthy controls. Mean trabecular bone volume and mean trabecular thickness were significantly reduced in both men and women with chronic liver disease (p less than 0.001 for both measurements in men and p less than 0.01 for both measurements in women). Osteoporosis as defined by histologic parameters was present in 17 (21%) patients with no significant differences in prevalence rates among the various hepatic disorders. No patient had histologic evidence of osteomalacia, although mineralization lag times were prolonged (p less than 0.01 for men and women). Bone formation rates were significantly reduced in 46 (57%) patients, and unlike the static measurements, were related to the type and severity of the underlying liver disease. Patients with alcoholic liver disease, hemochromatosis, and cholestatic liver disease had lower bone turnover rates and osteoblastic surfaces (p less than 0.001 and p less than 0.05, respectively) than patients with chronic active hepatitis. Furthermore, the presence of hepatic cirrhosis was associated with diminished bone formation and lower osteoblast surfaces. Serum bone Gla-protein levels were significantly correlated with bone formation rates and osteoblast surfaces (r = 0.585 and r = 0.434, respectively). A reduction in osteoblast surfaces has not previously been demonstrated in liver disease. This reduction and the associated impairment of osteoblastic activity may contribute to the pathogenesis of osteoporosis and can be assessed by the measurement of serum bone Gla-protein.

Adult↗
PubMed1987

Hypercalcaemia in the Johannesburg Hospital. Differential diagnosis and physician awareness of primary hyperparathyroidism.

A 1-year retrospective study of all serum profiles of patients with hypercalcaemia analysed at the Johannesburg Hospital was carried out to ascertain the causes of hypercalcaemia and physician awareness of primary hyperparathyroidism. Hypercalcaemia was found in 560 subjects (2.9% of 19,200), but in 147 of these (26%) this was not confirmed by repeat estimations. Malignant tumours were the commonest cause (38.4%) and accounted for the most severe hypercalcaemia (mean serum calcium 2.93 mmol/l). Renal disease resulted in significant hypercalcaemia, at times requiring parathyroidectomy. Drug-associated hypercalcaemia was usually mild and reversible on drug withdrawal. Although primary hyperparathyroidism occurred in 21.3% of cases, overall physician awareness of the disease was poor (39%). 'Incidental' profile hypercalcaemia (P less than 0.005) and hypertension (P less than 0.005) were frequent presenting features in this study. Renal disease (P less than 0.001) occurred infrequently.

Calcium↗
PubMed1987

Disseminated Blastomyces dermatitidis infection in a non-endemic area. A case report.

In areas where tuberculosis is endemic other causes of respiratory infection are often overlooked. A pulmonary infiltrate associated with skin lesions without a microbiological diagnosis of tuberculosis should arouse suspicion of a fungal infection. This was demonstrated in a patient in whom Blastomyces dermatitidis, a rare pathogen in southern Africa, was isolated.

Adult↗
PubMed1987

Diabetes in pregnancy. The use of home blood glucose monitoring and intensive monitoring to ensure favourable perinatal outcome.

A combined clinic for pregnant diabetic women was established at Baragwanath Hospital to assess the effects of intensive monitoring of mother and fetus and of good glycaemic control on perinatal outcome. Home blood glucose monitoring was introduced as a method for assessing glycaemic control. Standard methods of maternal and fetal monitoring were used. Sixty-two diabetic pregnancies were evaluated prospectively. Twenty women had diabetes diagnosed for the first time in the current pregnancy and the remaining 42 had established diabetes. All patients followed a diabetic diet, and 95% were treated with insulin. The technique and accurate recording of blood glucose were managed by all patients, and a mean capillary blood glucose of 6.5 mmol/l for the group was achieved. Caesarean section was performed in 52% of cases with a mean period of gestation at the time of delivery for the total study population of 37 weeks. The mean neonatal weight was 3,130 g. The perinatal mortality rate of 64/1,000 was accounted for by 3 stillbirths and 1 early neonatal death. No major congenital anomalies occurred.

Adult↗
PubMed1987

Hyperkalaemia secondary to hypo-aldosteronism. A report of 2 cases differentiating hyperreninaemic from hyporeninaemic hypo-aldosteronism.

Hypo-aldosteronism has been considered an important pathophysiological mechanism in the development of hyperkalaemia. This may occur as a consequence of defective regulatory mechanisms in the plasma renin-angiotensin-aldosterone system. Two case reports of hyperkalaemia are described which illustrate the differentiation of hyperreninaemic from hyporeninaemic hypo-aldosteronism. Laboratory investigations, together with measurements of plasma renin activity and aldosterone concentrations during adrenocorticotrophic hormone stimulation and sodium depletion, demonstrated this difference. Appropriate therapy with fludrocortisone (Florinef; Squibb) and furosemide (Lasix; Hoechst) respectively returned the situation to normal.

Aldosterone↗
PubMed1986

Primary hyperparathyroidism. A study of 100 patients in Johannesburg.

This study comprised 100 white patients with primary hyperparathyroidism treated between 1975 and 1984. Of these, 75 attended Johannesburg Hospital and 25 were managed by private practitioners. The mean age was 56.4 +/- 1.4 years at the time of diagnosis. There were almost twice as many women as men. In patients attending Johannesburg Hospital there was a progressive increase in the detection rate after 1979, which corresponded with the introduction of automated multichannel serum analysis. The commonest major complications were renal stones (54%), renal insufficiency (27%), a history of skeletal fractures (12%), radiographic evidence of osteopenia (38%) and peptic ulcers (20%). Bone disease was particularly common in postmenopausal women (64%). Other notable features were the frequency of weakness and fatigue (40%) and hypertension (45%). Coincidental thyroid abnormalities were frequent (18%). Ninety-three patients were treated surgically; 76 (81.7%) had a single adenoma. Our findings are compared with those of other large series. This study indicates the need for a greater awareness of this condition and earlier diagnosis to forestall the development of its harmful complications, and for the collection of additional information from a prospective study.

Adolescent↗
PubMed1985

Persistent ST-segment elevation in patients with anterior myocardial infarctions. Evaluation by exercise electrocardiography, echocardiography and Holter monitoring.

One hundred and seventy patients who suffered an acute myocardial infarction (MI) were followed up at 3-monthly intervals by a full clinical evaluation, exercise electrocardiography and ambulatory Holter monitoring. Fifty-eight patients (34%) had anterior MIs, and of these 23 (40%) had persistent ST-segment elevation over the infarct zone, reflected by leads presenting with Q-S configuration. Fifteen (65,2%) of the latter demonstrated further ST-segment elevation during exercise. They were further investigated by cross-sectional echocardiography. Left ventricular (LV) dysfunction was diagnosed in 87% of patients with persistent ST-segment elevation, and in 93% of the patients with additional exercise-induced ST-segment elevation. Organized thrombi occurred in 2 patients (8,7%) and 1 experienced a transient ischaemic attack. Ventricular arrhythmias occurred frequently (ventricular ectopy--91,3%, ventricular tachycardia--17,4%, and couplets--47,8%). Death occurred in 3 patients (13,1%) and 1 patient (4,3%) had a second MI over a mean follow-up period of 83,6 months. This study suggests that persistent ST-segment elevation on the resting ECG of patients with anterior MIs is a reliable indicator of LV wall motion abnormalities, and that this correlation further increases if it is associated with exercise-induced ST-segment elevation. Furthermore, the role of echocardiography as a diagnostic tool in evaluating LV function is stressed. The prognosis of patients with post-infarction LV dysfunction is notably poor and may be the result of frequent complex ventricular arrhythmias.

Arrhythmias, Cardiac↗