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Biomedical subjects

D J Tymms

Publications and source records attributed to D J Tymms.

8 recordsLinked to original sources
PubMed1989

Hormonal response to blood volume expansion in diabetic subjects with and without autonomic neuropathy.

The hormonal and renal response to volume expansion, produced by water immersion for 4 h, was studied in 14 insulin-dependent diabetic subjects (seven without complications, seven with autonomic neuropathy) and in 14 age-and-sex-matched normal control subjects. The diabetic subjects showed an impaired natriuretic response to volume expansion (total amount of sodium excreted 21 mmol compared to 39 mmol in normals, P less than 0.01) but the response did not differ in those with and without autonomic neuropathy. There was no significant difference in the suppression of plasma renin or aldosterone during immersion in either group. Plasma catecholamines suppressed on immersion in all groups. Basal values were lowest in the group with autonomic involvement. Atrial natriuretic peptide levels showed a twofold rise (from 4.8 to 9.6 pmol/l, P less than 0.01) on immersion. There was no significant difference in the levels of this hormone between diabetic patients and normal subjects or between those diabetics with and those without autonomic neuropathy. The present study confirms that diabetic subjects retain sodium avidly during volume expansion. This enhancement cannot be ascribed to any measurable difference in the levels of circulating hormones known to be involved in natriuresis and is not influenced by the presence of autonomic neuropathy.

Adult↗
PubMed1989

Proliferative diabetic retinopathy in a patient with maturity-onset diabetes of the young (MODY).

Maturity-onset diabetes of the young (MODY) has been described as being characteristically free from severe complications. This has led to speculation that the type of diabetes may be important in the pathogenesis of complications in diabetes. We report a case of classical MODY in which severe proliferative diabetic retinopathy developed. The retinopathy was detected shortly after the diagnosis of diabetes was made when the patient was 32 years old, and did not progress subsequently. No further complications developed during the subsequent 29 years in which normal postprandial plasma glucose levels were maintained with chlorpropamide therapy (mean 4.7, range 4.1-6.0 mmol I-1). This case demonstrates that severe retinopathy can occur in MODY and we suggest that in this patient there may have been a period of hyperglycaemia prior to diagnosis which was sufficient to lead to the microvascular complication.

Adolescent↗
PubMed1988

Lactic acidosis due to metformin therapy in a low risk patient.

A 55 year old diabetic women treated with chlorpropamide and metformin for three years presented with acute oliguric renal failure and lactic acidosis from which she died. The plasma metformin level was very high suggesting that the lactic acidosis was caused by the drug. There were no contraindications to metformin therapy and renal function was normal three months previously. This case demonstrates that lactic acidosis can occur as a result of metformin therapy in the absence of pre-existing risk factors.

Acidosis, Lactic↗
PubMed1988

The effect of continuous subcutaneous insulin infusion (CSII) on microvascular blood flow in diabetes mellitus.

The effects of strict blood glucose control on total skin blood flow and capillary blood flow velocity in finger nailfold capillaries were assessed in nine diabetics. Measurements were made before (blood glucose: 11.2 +/- 0.8 mmol/l) and after nine days of continuous subcutaneous insulin infusion (CSII) (blood glucose 6.2 +/- 0.8 mmol/l, p less than 0.001). Resting finger skin blood flow, measured by venous occlusion plethysmography, was 18.6 +/- 2.7 ml/100 ml tissue/min before and 12.6 +/- 2.7 ml/100 ml/min (ns) after CSII. Nailfold capillary red cell velocity, measured by television video microscopy, rose significantly from 0.36 +/- 0.09 mm/s before to 0.71 +/- 0.14 mm/s (p less than 0.01) after CSII. Venous oxygen tension, measured in samples of blood taken from an antecubital vein, tended to fall after CSII (from 6.1 +/- 0.4 kPa to 4.6 +/- 0.5 kPa/ns). No change was seen in whole blood viscosity, plasma viscosity or red cell filtration rate during the study although heart rate fell from 81.3 +/- 2.0 to 75.2 +/- 1.7 beats/min (p less than 0.02). The results suggest that there is a redistribution of skin blood flow following improved diabetic control which favours the nutritive microcirculation.

Aged↗
PubMed1980

Oat cell carcinoma, phaeochromocytoma and carcinoid tumours--multiple APUD cell neoplasia--a case report.

A case of non-familial multiple APUD cell neoplasia is described in which an oat cell carcinoma occurred in association with a phaeochromocytoma and two gastric carcinoids. This is the first reported case in which an oat cell carcinoma has formed part of such a syndrome. The arguments for and against this being a chance association are briefly stated and it is suggested that this case provides some support for the view that oat cell carcinomas are themselves derived from APUD cells. The same patient had autoimmune disease, and although this may be purely fortuitous, a speculative hypothesis is advanced suggesting that the deranged anterior pituitary trophic function seen in Hashimoto's thyroiditis may have predisposed to multiple endocrine neoplasia in this case.

Adrenal Gland Neoplasms↗
PubMed1980

Thyroid function tests during carbimazole therapy.

Changes in plasma thyroxine (T4), triiodothyronine (T3), free thyroxine index (FT4I) and thyroid stimulating hormone were studied in 100 patients with Graves' disease treated with carbimazole. During therapy plasma T3 concentrations were disproportionately high compared to those of T4, the T4 : T3 ratio was low, and many patients were clinically euthyroid with a normal plasma T3 but low T4 concentration. Although there was considerable individual variation in response, the order of response was always the same with plasma T4 falling to normal or low levels before T3. Plasma T3 was the best indicator of clinical status and the best predictor of the impending change; additional information of changes in thyroid status was obtained from plasma T4 and FT4I estimation, especially when these were followed sequentially. Single measurements of T4 or FT4I only are not recommended for assessing thyroid function during carbimazole therapy.

Adolescent↗