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Biomedical subjects

J A Weaver

Publications and source records attributed to J A Weaver.

At least 37 records · Page 2Linked to original sources
PubMed1982

Catecholamine content of chromaffin granule "ghosts' isolated from bovine adrenal glands.

Studies on the mechanism of catecholamine transport into chromaffin granules is complicated by the release of endogenous catecholamines. To overcome this problem chromaffin granule ghosts have been prepared by many investigators by osmotic lysis of the granules which results in a loss of over 90% of the endogenous catecholamine. However, in the studies reported here, the resulting ghosts still contained 36 +/- 3.9 nmol epinephrine/mg of protein if they were lysed by passage through a Sephadex G-50 column preequilibrated with hypoosmotic media. This residual catecholamine was found to slowly diffuse out of the ghosts in a temperature-dependent process at a rate sufficient to interfere with kinetic analysis of catecholamine transport. Attempts to remove the endogenous catecholamine from the ghosts indicated that most of it could not be removed by further osmotic shock of freeze-thaw treatments, but that over 85% of it was released from the granules by incubating them at 30 degree C for 90 min or by dialysis with a 35 and 86% loss of rate of catecholamine transport into the ghosts, respectively. If the endogenous catecholamine was removed from chromaffin granule ghosts by preincubating them for 90 min at 30 degree C, the resulting ghosts transported catecholamine with a linear Lineweaver-Burk plot indicating a Km of 12 +/- 2 microM. In addition, the resulting ghosts did not leak catecholamines over a 10 min period at 30 degree C, and the transport of catecholamines was blocked by reserpine and enhanced with increasing pH from 6.0 to 8.5.

Adenosine Triphosphate↗
PubMed1982

The effect of intensive dietary therapy on serum high density lipoprotein cholesterol in patients with Type 2 (non-insulin-dependent) diabetes mellitus: a prospective study.

Intensive dietary therapy in 57 newly diagnosed Type 2 (non-insulin-dependent) diabetic patients led to an increase, compared with pre-treatment levels, in serum high density lipoprotein (HDL) cholesterol and the HDL/total cholesterol ratio after 3 and 6 months (0.05 less than p less than 0.1). The increase in HDL cholesterol was related to the degree of weight loss achieved. In 28 patients whose weight decreased by greater than or equal to 10% average body weight during the 6 months, HDL cholesterol rose from 1.22 +/- 0.06 to 1.36 +/- 0.06 mmol/l (p less than 0.001), whereas patients who lost less weight showed no significant increase in HDL cholesterol. The increase in mean serum HDL-cholesterol levels in female patients was associated with a mean weight reduction of 12.1% average body weight. Patients who were obese at diagnosis lost more weight during the study than non-obese patients (mean 13.2 versus 5.6% average body weight), and showed a significant increase in serum HDL-cholesterol levels. We conclude that intensive dietary therapy may lead to a less atherogenic lipid profile in Type 2 diabetes, particularly in patients who achieve a major weight reduction.

Adult↗
PubMed1980

Dietary management of maturity-onset diabetes.

Dietary management of maturity-onset diabetes is a basic medical concept. It is difficult to study scientifically because of variable eating habits and the impossibility of rigorous measurement. The non-insulin-requiring diabetic patient is often managed by the family doctor, who may not have access to dietetic assistance, and assessment of the success of simple but careful dietary measures is infrequent. We have taken a special interest in this group of patients, and find that most maturity-onset diabetic patients can be satisfactorily managed on diet only. In a group of 58 such patients there was a significant fall in mean weight and fasting plasma glucose and triglyceride concentrations after six months, which persisted for up to three years. This achievement was chiefly due to those patients who were graded as "good" in their dietary adherence, but less good dieting still achieved weight loss, though plasma glucose and triglyceride concentrations did not fall so low. The clinical dietitian has played a central part in this study.

Adult↗
PubMed1980

Antithrombin III activity and other coagulation changes in proliferative diabetic retinopathy.

Antithrombin III, factor VIII, fibrinogen and fibrinolytic activity were measured in two groups of long-standing insulin-dependent diabetic subjects (24 with proliferative retinopathy, 24 without detectable retinopathy) and 24 non-diabetic controls. Mean antithrombin III (+/- 1 SD) was 115.9 (+/- 15.1), 109.8 (+/- 18.1) and 101.4% (+/- 12.5), respectively, in the retinopathy, non-retinopathy and control groups. Statistical significance was obtained when comparing the retinopathy and control groups (p < 0.001) and when comparing all 48 diabetics collectively with controls (p < 0.01). Mean factor VIII coagulant activity was 137.5 (+/- 37.0), 126.2 (+/- 58.2) and 97.0% (+/- 38.7), respectively, in the three groups. Again the differences between all diabetics and controls (p < 0.01) were statistically significant. Similar increases were observed for other modalities of factor VIII activity. Fibrinolytic activity was significantly increased in both diabetic groups but fibrinogen levels, although increased, were not statistically different from levels in controls. It is suggested that the observed changes are more likely to be secondary to the development of retinopathy and that the increase in antithrombin III activity is due to an increase in alpha 2-macroglobulin.

Adult↗
PubMed1979

The prognosis for diabetes.

Microvascular disease is the predominant manifestation of the juvenile-onset diabetic after the third decade of survival, while large vessel atheroma is the major problem in the long-term survival of the maturity-onset diabetic. From the experience of a diabetic-eye clinic, we would estimate that only about 3% of patients attending a hospital diabetic clinic would have a severe form of diabetic retinopathy which might need specialized ophthalmic photocoagulation treatment. The long-term visual prognosis for patients treated in this way remains under review. Among metabolic factors associated with vascular disease, a deficiency of HDL cholesterol may be important in the future prognosis of maturity-onset diabetes.

Arteriosclerosis↗
PubMed1978

Relation of high-density lipoprotein cholesterol concentration to type of diabetes and its control.

Serum cholesterol and high-density lipoprotein (HDL) cholesterol concentrations were measured in 192 diabetics (94 with juvenile-onset and 98 with maturity-onset diabetes) and 177 non-diabetic controls. Hb A1C, an index of blood sugar control, was also measured in the diabetics. Serum cholesterol concentrations were similar in all the diabetics and controls, but HDL cholesterol concentrations were lower in patients with maturity-onset diabetes than in those with juvenile-onset diabetes and controls. There was no correlation in diabetics between HDL cholesterol and Hb A1C. We conclude that HDL cholesterol concentrations are abnormally low in patients with maturity-onset diabetes but essentially normal in those with juvenile-onset diabetes. They are not related to diabetic control.

Adult↗
PubMed1975

Maturity onset diabetes mellitus: response to intensive dietary management.

Analysis of the first six months of intensive dietary management of 57 maturity onset diabetics showed that a large proportion of such patients could be satisfactorily controlled without the need of either oral hypoglycaemic agents or insulin. A dietitian's assessment of the patient's adherence to the prescribed diet allowed groups of good and poor dieters to be selected. Among the poor dieters the plasma insulin and triglyceride levels were significantly increased though plasma glucose levels were not significantly higher. Dietary adherence may thus be an prognostic risk factor in this group of diabetic patients.

Adult↗