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Biomedical subjects

A B Gustafson

Publications and source records attributed to A B Gustafson.

26 records · Page 2Linked to original sources
PubMed1981

Plasma epinephrine disturbances in diabetic subjects during standing and after isometric exercise.

Effects of isometric exercise on plasma norepinephrine (NE), epinephrine (E), and related factors (mean +/- SE) were studied in 10 healthy, insulin-dependent diabetic subjects and 10 matched control adults. Measurements were obtained after 30 min of bedrest and sequentially during 10 min of upright posture and 5 min of handgrip and after 15 min of rest while still upright. In control and diabetic groups, respectively, basal plasma NE (180 +/- 22 vs. 169 +/- 27 pg/ml) and E (24 +/- 4 vs. 33 +/- 8 pg/ml) as well as heart rate and mean blood pressure did not differ. However, E responses to standing and recovery from isometric exercise in diabetic subjects significantly exceeded control values 2-fold (P less than 0.05) and were accompanied by exaggerated increases in heart rate (P less than 0.05); whereas NE, mean blood pressure, plasma GH, and glucagon profiles during all periods were not significantly different. Exaggerated E responses in diabetic patients were associated with plasma glucose increments above resting values during grip and recovery of 21 and 41 mg/dl, respectively; slightly though significantly higher plasma cortisol responses, and low, fixed concentrations of plasma insulin. These findings contrasted to corresponding glucose increments in control subjects of only 3-4 mg/dl and a 2-fold rise in plasma insulin during recovery. It is concluded that E disturbances in this diabetic group after standing and isometric exercise are physiologically linked to abnormal increments in heart rate and plasma glucose concentrations. These observations suggest that altered E, as opposed to NE, may represent an early defect of the sympathoadrenal system in diabetes mellitus.

Blood Glucose↗
PubMed1980

Correlation of hyperprolactinemia with altered plasma insulin and glucagon: similarity to effects of late human pregnancy.

Plasma glucose and insulin concentrations were measured during oral glucose and iv tolbutamide tolerance tests in nine women with hyperprolactinemia and the amenorrheagalactorrhea syndrome (AGS). Glucose tolerance curves, basal insulin levels, and postchallenge plasma insulin responses were significantly higher in AGS women compared to those in an age- and weight-matched control group. Fasting plasma glucagon concentrations were unaltered in AGS, but suppression of the hormone after oral glucose was greater and more prolonged relative to the control response. Oral glucose tolerance tests were performed on nine normal women during late pregnancy who had physiological hyperprolactinemia comparable to that in the AGS group. Glucose tolerance curves, exaggerated plasma insulin responses, and glucagon suppression resembled those observed in the AGS women. These results suggest that elevated plasma PRL concentrations may contribute to the development of hyperinsulinemia and accentuated glucagon suppression in response to glucose that is characteristic of late human pregnancy.

Adult↗
PubMed1979

Cardiovascular and metabolic manifestations of heat stroke and severe heat exhaustion.

We prospectively studied the clinical, biochemical (including creatine phosphokinase (CPK) isoenzymes) and electrocardiographic features of exertional heat stroke in 13 patients (group 1) and severe heat exhaustion in 14 patients (group 2). Despite initial presentations with severe hyperthermia, tachycardia and hypotension, only one patient with heat stroke had myocardial ischemia. The CPK isoenzymes were not indicative of myocardial damage in any patient. The patients with heat stroke were somewhat more dehydrated than those with heat exhaustion as measured by differences in serum creatinine, sodium and osmolality, and the former (group 1) had a significantly lower initial glucose level (P less than 0.05). Although significant differences in potassium were not observed in the pretreatment samples, at 12 hours the serum potassium was significantly lower in group 1 (P less than 0.05). This suggests that this group may have been more potassium-depleted at the time of heat stroke. Prompt recognition and vigorous therapy were successful in rapidly lowering high temperatures and in preventing serious complications.

Alanine Transaminase↗
PubMed1978

Urinary free methyldopa determined by reversed-phase high-performance liquid chromatography.

We describe a chromatographic method, in which 3,4-dihydroxybenzylamine is used as the internal standard, for determining free methyldopa in human urine. The drug was adsorbed onto alumina, eluted, and the eluate directly injected onto a reversed-phase column (octadecyl-bonded silica stationary phase), with dilute acetate buffer (pH 2.7) as the mobile phase and ultraviolet detection at 280 nm facilitated. Methyldopa is well separated from other urinary biogenic amines present in the alumina extract, and other commonly used antihypertensives and diuretics do not interfere with the analysis. The sensitivity of the method is adequate to quantify 8.0 mg of methyldopa per liter in 30 ml of sample; the lower limit of detection is 25 ng. Analytical recovery for methyldopa varied from 95 to 102% with within-run and day-to-day coefficients of variation of 2.7 (n = 10) and 3.8% (n = 5), respectively. This procedure is readily adaptable for use in studies of the pharmacokinetics of methyldopa and to routine clinical laboratory use.

Adult↗
PubMed1977

Urinary free norepinephrine and dopamine determined by reverse-phase high-pressure liquid chromatography.

We used reverse-phase high-pressure liquid chromatography to measure free norepinephrine and dopamine simultaneously in human urine. Samples were treated with alumina, and the catecholamine(s) then eluted from it were directly injected onto a reverse-phase column (octadecyl-silica stationary phase), with 0.17 mol/liter acetic acid as the mobile phase and ultraviolet detection at 280 nm. The assay detects concentrations in urine as low as 5 mug/liter. Assay of 24-h urines (n = 10) gave within-run and day-to-day coefficients of variation of 3.7 and 4.7% for norepinephrine, and 2.6 and 3.5% for dopamine, respectively. Comparison studies with the traditional trihydroxyindole fluorometric method showed the liquid-chromatographic procedure to be more precise and subject to less interference. This relatively rapid procedure for urinary free norepinephrine and dopamine provides an efficient, reproducible method, readily adaptable to routine clinical use.

Ascorbic Acid↗
PubMedDate not supplied

Current therapeutic concepts in diabetic hypertension.

Diabetes mellitus and hypertension are both prevalent in the adult population. The development of hypertension in the diabetic patient is likely to increase the morbidity and mortality in a subgroup already at high risk for atherosclerosis and deserves special consideration. Several studies have confirmed the beneficial effects of antihypertensive therapy on complications such as diabetic nephropathy. This emphasizes the importance of normalizing blood pressure in the diabetic population. It has been suggested that the threshold for initiating antihypertensive therapy should be lower in diabetic patients. All antihypertensive agents have potential disadvantages in patients with diabetes. The commonly encountered effects include deterioration of diabetic control, sexual dysfunction, electrolyte imbalance, and lipid disorders. The adverse effects of these agents on serum lipids have been implicated in the less-than-expected reduction in coronary heart disease noted in some studies. The recent Lipid Research Council study has emphasized the importance of elevated lipid levels and increased cardiovascular mortality. Antihypertensive therapy has advanced rapidly in the last 5 yr. The special problems in the treatment of hypertension within the diabetic population are now receiving greater attention. Undesirable biochemical side effects of drugs used to treat hypertension have become publicized, and the long-term consequences of these abnormalities are under critical scrutiny. The new antihypertensive medications offer exciting alternative approaches to the more traditional agents with less chance of significant metabolic side effects.

Antihypertensive Agents↗