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Biomedical subjects

F L Dunn

Publications and source records attributed to F L Dunn.

At least 37 records · Page 2Linked to original sources
PubMed1987

Treatment with artificial beta-cell decreases very-low-density lipoprotein triglyceride synthesis in type I diabetes.

The effect of restoration of euglycemia with the artificial beta-cell (Biostator GCIIS) on triglyceride metabolism was studied in seven normolipidemic patients with type I diabetes mellitus. Very-low-density lipoprotein triglyceride (VLDL-TG) transport was determined with [3H]glycerol as an endogenous precursor of VLDL-TG; the resultant kinetic data were evaluated by multicompartmental analysis. Studies of triglyceride metabolism were performed in diabetic patients taking their usual dose of subcutaneous insulin (control study) and after 72 h of euglycemia with the artificial beta-cell (Biostator study). Treatment with the artificial beta-cell resulted in a decrease in mean (+/- SE) 24-h plasma glucose levels from 199 +/- 9 to 123 +/- 7 mg/dl and an increase in mean plasma free-insulin levels from 12.3 +/- 1.9 to 27.6 +/- 4.2 microU/ml (P less than .05). These changes were accompanied by a decrease in mean plasma TG levels from 134 +/- 29 to 88 +/- 15 mg/dl (P less than .05). Kinetic studies demonstrated that the change in plasma triglyceride levels was primarily due to a decrease in VLDL-TG transport (i.e., synthesis), which fell from 11.7 +/- 2.5 mg X h-1 X kg-1 ideal wt during the control study to 7.5 +/- 2.0 mg X h-1 X kg-1 ideal wt during the Biostator study (P less than .05). There was no significant change in fractional catabolic rates of VLDL-TG between the two studies (0.35 +/- .05 vs. 0.38 +/- .07 h-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Impaired catabolism of very low-density lipoprotein-triglyceride in a family with primary hypertriglyceridemia.

In this report, kinetic studies of plasma very low-density lipoprotein-triglyceride (VLDL-TG) were examined in five brothers (three affected and two unaffected) from a family with primary hypertriglyceridemia. Synthesis and catabolism of VLDL-TG were studied by in vivo labelling of plasma TG with 3H-glycerol, and multicompartmental analysis of the plasma die-away curves. Results of the kinetic studies revealed the following information: (1) one brother, who had the highest plasma TG level and was obese, had both overproduction and a reduced fractional catabolic rate (FCR) of VLDL-TG; (2) second brother, who had moderate hypertriglyceridemia, had a low FCR and high-normal synthesis of VLDL-TG; (3) a third, who had only mildly elevated TG, had a low FCR and normal synthesis of VLDL-TG; and (4) the two normolipidemic brothers had neither overproduction nor decreased FCR of VLDL-TG. The composition of the soluble apoproteins of VLDL was normal. The apoprotein E phenotypes were E4/3 in four brothers, and E3/2 in the fifth. We have reached the following conclusions regarding this family: (1) the common kinetic abnormality of VLDL-TG metabolism in the hypertriglyceridemic brothers was a low clearance of VLDL-TG; (2) impaired catabolism of VLDL could not be explained by the apoprotein C or E patterns; and (3) the most severe hypertriglyceridemia occurred when the decreased FCR was present in conjunction with VLDL-TG overproduction due to obesity. Thus, a moderate defect in catabolism of plasma TG appears to be responsible for one familial form of primary hypertriglyceridemia.

Adult↗
PubMed1984

The effect of diabetic control on very low-density lipoprotein--triglyceride metabolism in patients with type II diabetes mellitus and marked hypertriglyceridemia.

We examined the effect of diabetic control on very low-density lipoprotein-triglyceride (VLDL-TG) metabolism in six patients with type II (noninsulin-dependent) diabetes mellitus and marked hypertriglyceridemia. VLDL-TG transport was determined using 3H-glycerol as an endogenous precursor of VLDL-TG, and the resultant kinetic data were evaluated by multicompartmental analysis. Studies were performed in the hypertriglyceridemic diabetic subjects during poor diabetic control and again after 3 months of diabetic treatment, and the results were compared to studies in nondiabetic normolipidemic subjects and nondiabetic subjects with familial forms of hypertriglyceridemia. In the poorly controlled diabetics, mean VLDL-TG synthesis was threefold higher than in the normolipidemic subjects, and the mean fractional catabolic rate (FCR) of VLDL-TG was only one-third of the normals. With diabetic treatment, plasma triglyceride levels fell by more than 50%, but remained fourfold higher than the normals. This was associated with a decrease in mean VLDL-TG synthesis to a level similar to that observed in the genetic hyperlipidemic subjects, but still 2.6-fold higher than the normals. In addition, the mean FCR rose after diabetic control to a level slightly above that of the genetic hyperlipidemic subjects, but remained less than one-half of the normal value. However, the response of VLDL-TG kinetics to diabetic treatment was not uniform. In four subjects, control of hyperglycemia ameliorated the hypertriglyceridemia primarily by decreasing VLDL-TG overproduction. In the other two subjects, diabetic treatment had a greater effect on the FCR than an overproduction of VLDL-TG. Thus, in this select group of diabetic, hypertriglyceridemic subjects, poor diabetic control contributed to both VLDL-TG overproduction and low FCRs. Failure of diabetic treatment to restore VLDL-TG kinetic parameters to normal suggests that the hypertriglyceridemia was due not only to diabetes mellitus but also to an additional abnormality affecting lipoprotein metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1981

Plasma lipid and lipoprotein levels with continuous subcutaneous insulin infusion in type I diabetes mellitus.

Plasma lipid and lipoprotein-cholesterol levels were measured in 10 insulin-dependent (Type I) diabetics taking their usual dose of conventionally administered insulin during 6 months of a continuous subcutaneous insulin infusion delivered with a small, portable, battery-powered pump. With this insulin delivery system we were able to provide near normal glucoregulation 24 hours a day for the entire study. This improved glucoregulation resulted in significant reductions in total plasma cholesterol and triglyceride, and very low density and low density lipoprotein-cholesterol levels within 2 to 4 weeks of treatment. These changes persisted for the entire 6 months of observation. High density lipoprotein-cholesterol levels rose significantly after 2 months of treatment and continued to increase during the 6-month study. These changes in plasma lipid and lipoprotein-cholesterol levels in response to treatment with continuous subcutaneous insulin infusion would favorably alter the predicted risk for the development of premature atherosclerosis in these patients.

Adolescent↗
PubMed1980

The effect of improved diabetic control on plasma lipid and lipoprotein levels: a comparison of conventional therapy and continuous subcutaneous insulin infusion.

We studied short-term changes in plasma lipid levels in type I diabetics treated with either a conventional insulin regimen or continuous subcutaneous insulin infusion. Mean plasma glucose dropped from 260 +/- 18 to 134 +/- 8 mg/dl when conventional treatment was used and from 194 +/- 18 to 108 +/- 8 mg/dl with CSII. Both forms of therapy were associated with a significant fall in plasma triglyceride levels. However, only CSII treatment produced significant changes in total plasma cholesterol and LDL cholesterol levels. Total cholesterol fell from 195 +/- 17 mg/dl to 161 +/- 11 mg/dl and LDL cholesterol fell from 129 +/- 13 mg/dl to 102 +/- 9 mg/dl. We conclude that improved diabetic control by any method is effective in lowering plasma triglyceride levels, but it requires almost perfect metabolic control to affect plasma cholesterol and LDL cholesterol levels. The changes in plasma lipid and lipoprotein achieved with CSII may favorably alter the prediction for the development of premature atherosclerosis in our patients.

Adult↗
PubMed1979

Behavioural aspects of the control of parasitic diseases.

Human behaviour has been largely neglected in research on the parasitic diseases, in part because of the long-standing separation of the behavioural disciplines from the physical and biomedical sciences. Some of the reasons for the persistence of this "intellectual discontinuity" are discussed. The paper is principally concerned with the prospects for greater use of the methods and orientations of the behavioural sciences in parasitic disease research and control programmes. Behavioural research tends to fall into two categories employing, on the one hand, survey research and epidemiological methods and, on the other, participant observation and interviewing in depth. These approaches are shown to be complementary-equally useful and necessary. Various categories of health-related behaviour and kinds of research objective are reviewed in the following sections. Special attention is given to psychosocial cost-benefit studies, to analyses of control sectors, and to the formulation of a control philosophy. Finally, some specific behavioural research needs are discussed for some of the parasitic diseases of priority in the UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases-schistosomiasis, filariasis, American and African trypanosomiases, and malaria.

Attitude to Health↗
PubMed1973

The role of blood osmolality and volume in regulating vasopressin secretion in the rat.

A sensitive and specific radioimmunoassay for plasma arginine vasopressin (AVP) has been used to study the effects of blood osmolality and volume in regulating AVP secretion in unanesthetized rats. Under basal conditions, plasma AVP and osmolality were relatively constant, averaging 2.3+/-0.9 (SD) pg/ml and 294+/-1.4 mosmol/kg, respectively. Fluid restriction, which increased osmolality and decreased volume, resulted in a progressive rise in plasma AVP to about 10 times basal levels after 96 h. A 2-3-fold increase in plasma AVP occurred as early as 12 h, when osmolality and volume had each changed by less than 2%. Intraperitoneal injections of hypertonic saline, which had no effect on blood volume, also produced a rise in plasma AVP that was linearly correlated with the rise in osmolality (r > 0.9) and quantitatively similar to that found during fluid restriction (plasma AVP increased 2-4-fold with each 1% increase in osmolality). Intraperitoneal injection of polyethylene glycol, which decreased blood volume without altering osmolality, also increased plasma AVP but this response followed an exponential pattern and did not become significant until volume had decreased by 8% or more. At these levels of hypovolemia, the osmoregulatory system continued to function but showed a lower threshold and increase sensitivity to osmotic stimulation. We conclude that AVP secretion is regulated principally by blood osmolality but that the responsiveness of this mechanism may be significantly altered by modest changes in blood volume.

Animals↗
PubMed1972

Intestinal parasitism in Malayan aborigines (Orang Asli).

Surveys were conducted in the southern Malay peninsula to assess intestinal parasitism in the aboriginal ethnic minority groups. Faecal specimens from 1 273 persons were examined by the thiomersal-iodine-formol direct-smear technique. Prevalences are reported and, for helminth infections, data on worm burdens. The state of sanitation in each of 9 cultural-ecological groups was assessed by means of a simplified system of scoring for variables. Particular attention was paid to relationships between cultural and ecological factors, sanitation, and observed patterns of intestinal parasitism. The author also discusses the fact that the number of parasitic species diminishes in habitats simplified by man, whereas an increase occurs in the prevalence and intensity of the more adaptable species that persist in ecosystems of low complexity.

Adolescent↗