Plasma l-[3H]norepinephrine, d-[14C]norepinephrine, and d,l-[3H]isoproterenol kinetics in essential hypertension.

We infused tracer-labeled l-[3H]-norepinephrine, d-[14C]norepinephrine, and d,l-[3H]-isoproterenol simultaneously into patients with essential hypertension and into normotensive control subjects, in order to determine whether abnormalities in the disappearance kinetics of these substances characterized the hypertensive patients. The mean preinfusion venous plasma norepinephrine concentration was somewhat higher in the hypertensive group (260 vs. 194 pg/ml, P = 0.

Can aspartame meet our expectations?

Aspartame is a dipeptide containing aspartic acid and phenylalanine methyl ester. It is a nutritive sweetener with a caloric value equivalent to that of other proteins and with sweetness approximately 180 times that of sucrose. Thus, for equivalent sweetening power, it contributes only 0.

T lymphocyte subsets in systemic lupus erythematosus. Correlations with corticosteroid therapy and disease activity.

The contribution of immune regulation to the etiology of systemic lupus erythematosus (SLE) is poorly understood. Using the monoclonal antibodies OKT4 and OKT8, we quantitated, by flow cytometry, T inducer/helper and T cytotoxic/suppressor cells in patients with SLE. Serologically active patients, who had clinical manifestations such as arthritis or rash and were not receiving prednisone, were characteristically lymphopenic due to a marked reduction in OKT4+ cells.

Defective production of interleukin 1 and interleukin 2 in patients with systemic lupus erythematosus (SLE).

The objective of this study was to define some causes of the immunologic impairment characteristic of systemic lupus erythematosus. Blood mononuclear cells from 19 patients were stimulated to produce interleukin 1 and interleukin 2 and compared with controls. A severe defect in both IL 1 and IL 2 activity was observed.

Fludrocortisone suppression of sympathetic nervous activity.

Fludrocortisone depressed plasma norepinephrine in normal subjects but to a lesser degree than it depressed renin activity or urinary aldosterone excretion. Sympathetic nervous reactivity (defined as upright/supine plasma norepinephrine) was decreased more than supine plasma norepinephrine. Pretreatment supine plasma norepinephrine (but not plasma renin activity or aldosterone excretion) correlated with blood pressure changes during fludrocortisone dosing, which suggests participation of the sympathetic nervous system in the blood pressure elevations reported during exogenous steroid administration or primary aldosteronism.

Contrasting effects of lactoferrin on human lymphocyte and monocyte natural killer activity and antibody-dependent cell-mediated cytotoxicity.

Iron and the iron-binding protein lactoferrin (LF) have significant effects on natural killer (NK) and antibody-dependent cellular cytotoxicity (ADCC). Human adherent and nonadherent blood mononuclear cells were incubated with K562 cells and antibody-sensitized Chang cells in short-term chromium-release assays. Ferric citrate (10(-3) M) inhibited both adherent and nonadherent NK cell activity, but had no effect upon ADCC.

Comparison of techniques for measuring baroreflex sensitivity in man.

Because discrepancies about baroreflex sensitivity in essential hypertension may have resulted from the use of different measurement techniques, we assessed the extent to which the results of different techniques agree in the same subjects. The eight techniques studied were the change in RR interval per unit change in systolic pressure during the Valsalva maneuver, upon release of the Valsalva maneuver, after injection of phenylephrine and after injection of nitroglycerin; the changes in RR interval and in systolic pressure per mm Hg externally applied neck suction; and the changes in RR interval and systolic pressure per mm Hg externally applied neck pressure. The average intercorrelation among these measures in 30 subjects was statistically significant (r = 0.

Effects of restriction of sodium or administration of fludrocortisone on parotid salivary kallikrein in man.

Urinary kallikrein is increased by restriction of dietary sodium and by administration of fludrocortisone, a sodium-retaining steroid. In order to determine whether salivary kallikrein responds similarly, we studied 16 normal volunteers after 1-week periods of daily intake of 9, 109, and 259 mEQ of sodium; 10 subjects were studied after addition of 0.6 mg/day fludrocortisone for a week to a regimen of 109 mEq/day sodium.

Defective monocyte cytotoxicity in rheumatoid arthritis: a correlation with disease activity and reversal by levamisole.

The cytotoxic activities of human blood mononuclear cells against certain established cell lines were evaluated prospectively in 17 patients with rheumatoid arthritis before and after treatment with low (150 mg per week) and moderate doses (300 mg per week) of levamisole. Spontaneous or "natural" killer activity (NK) and antibody-dependent cellular cytotoxicity (ADCC) of plastic adherent cells ("monocytes") and lymphocytes were studied. We report a selective cytotoxic defect in monocyte NK and a correlation of this defect with severely active disease.

Regulation of antigen-induced lymphoproliferation by BSA gradient-separated T cell fractions.

Human T cells from 6 volunteers immunized with keyhole limpet hemocyanin (KLH) or tetanus toxoid were fractionated on bovine serum albumin (BSA) gradients. These T cell fractions were then recombined with autologous unseparated mononuclear cells or unseparated T cells to determine the effect of each fraction on the proliferative (DNA synthetic) response to the immunizing antigen. Using this separation technique, we were able to define 2 fractions of T cells of widely different densities that had a suppressive effect on the proliferative response to KLH of unfractionated T cells.

Effects of mild hyperinsulinemia on the metabolic response to exercise.

To assess the effects of mild hyperinsulinemia on the metabolic adaptations to exercise, five normal male subjects were studied during 2 cycles of 30 min rest followed by 60 min mild exercise. During one cycle, insulin was infused at a rate of 0.33 mU/kg/min.