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Biomedical subjects

S Rubenfeld

Publications and source records attributed to S Rubenfeld.

7 recordsLinked to original sources
PubMed1979

Impact of hemodialysis on the abnormal glucose and alanine kinetics of chronic azotemia.

Rates of alanine and glucose turnover and precursor-product interrelationships were determined in patients on chronic hemodialysis and in matched controls using simultaneous primed injection-continuous infusions of [U-14C] alanine and [2-3h] glucose. In eight chronically dialyzed patients studied before their first dialysis of the week, glucose turnover was 866 +/- 120 micromole/min (mean +/- SE); after their last dialysis of the week, glucose turnover was 880 +/- 63 micromole/min. These rates were 35% (p less than 0.05) and 37% (p less than 0.01) greater than rates observed in ten normal volunteers (642 +/- 28.3 micromole/min). Fasting glucose and insulin levels in dialyzing patients were unchanged from normal. Alanine turnover was increased predialysis (318 +/- 55.2 micromoles/min; p less than 0.01) and postdialysis (248 +/- 32.4 micromole/min; p less than 0.01) as compared to normal (168 +/- 14.3 micromole/min). In patients pre- and postdialysis, gluconeogenesis from alanine was increased to 34.6 +/- 10.9 micromole/min (p less than 0.05) and 39.0 +/- 6.33 micromole/min (p less than 0.05) compared to 20.9 +/- 1.63 micromole/min in normal subjects. We conclude that neither acute nor chronic hemodialysis corrects the increased glucose and alanine production and utilization and gluconeogenesis observed in chronic renal failure.

Adult↗
PubMed1978

Abnormal carbohydrate metabolism in chronic renal failure. The potential role of accelerated glucose production, increased gluconeogenesis, and impaired glucose disposal.

To delineate the potential role of disordered glucose and glucose-precursor kinetics in the abnormal carbohydrate metabolism of chronic renal failure, alanine and glucose production and utilization and gluconeogenesis from alanine were studied in patients with chronic compensated renal insufficiency and in normal volunteers. With simultaneous primed injection-continuous infusions of radiolabeled alanine and glucose, rates of metabolite turnover and precursor-product interrelationships were calculated from the plateau portion of the appropriate specific activity curves. All subjects were studied in the postabsorption state. In 13 patients with chronic renal failure (creatinine = 10.7+/-1.2 mg/100 ml; mean+/-SEM), glucose turnover was found to be 1,035+/-99.3 mumol/min. This rate was increased 56% (P = 0.003) over that observed in control subjects (664+/-33.5 mumol/min). Alanine turnover was 474+/-96.0 mumol/min in azotemic patients. This rate was 191% greater (P = 0.007) than the rate determined in control subjects (163+/-19.4 mumol/min). Gluconeogenesis from alanine and the percent of glucose production contributed by gluconeogenesis from alanine were increased in patients with chronic renal failure (192% and 169%, respectively) as compared to controls (P < 0.05 for each). Alanine utilization for gluconeogenesis was increased from 40.2+/-3.86 mumol/min in control subjects to 143+/-39.0 mumol/min in azotemic patients (P < 0.05). The percent of alanine utilization accounted for by gluconeogenesis was not altered in chronic renal insufficiency. In nondiabetic azotemic subjects, mean fasting glucose and immunoreactive insulin levels were increased 24.3% (P = 0.005) and 130% (P = 0.046), respectively.These results in patients with chronic renal failure demonstrate (a) increased glucose production and utilization, (b) increased gluconeogenesis from alanine, (c) increased alanine production and utilization, and (d) a relative impairment to glucose disposal. We conclude that chronic azotemia is characterized by increased rates of glucose and glucose precursor flux and by a relative impairment to glucose disposal. These findings may suggest an underlying hepatic and peripheral insensitivity to the metabolic action of insulin in patients with chronic renal insufficiency.

Adult↗
PubMed1978

Effects of guanadrel on patients with thyrotoxicosis.

Eleven patients with Graves' disease were treated with guanadrel sulfate and observed for changes in neuromuscular and cardiovascular manifestations. No notable changes in pulse rate or muscle strength were detected in either these patients during a three-day pretreatment period or in five control patients with Graves' disease receiving placebo for six days. Thyroid hormone levels were not altered by seven days of guanadrel sulfate therapy (5 to 20 mg orally every six hours), and no adverse side effects were encountered. Mean supine resting pulse fell from 102 +/- 6 (mean +/- SEM) to 90 +/- 3 beats per minute (P less than .02). The patients' proximal and distal muscle strengths were initially decreased, when compared with healthy subjects, and improved substantially with guanadrel therapy. We conclude that guanadrel sulfate may be useful in the symptomatic management of patients with thyrotoxicosis.

Adult↗
PubMed1977

Leukocytoclastic angiitis in subacute bacterial endocarditis.

The case of a patient who had palpable purpura on his lower extremities due to Lactobacillus-caused subacute bacterial endocarditis is reported. Histologic examination of the purpuric lesions demonstrated a leukocytoclastic angiitis. It is postulated that purpuric and other cutaneous lesions of subacute bacterial endocarditis are related to circulating immune complexes.

Adult↗