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Biomedical subjects

H W Schnaper

Publications and source records attributed to H W Schnaper.

15 recordsLinked to original sources
PubMed1992

Angiotensin-converting enzyme inhibitors for systemic hypertension in young and elderly patients.

Whereas many physicians have been reluctant to treat hypertension in the elderly because of perceived limited benefits and the risk of side effects associated with traditional antihypertensive agents such as diuretics and beta blockers, studies and clinical experience have shown that elderly as well as younger patients can benefit from treatment. In recent years, angiotensin-converting enzyme (ACE) inhibitors have been found to be safe and effective in both young and elderly hypertensive patients without many of the adverse effects associated with traditional agents. ACE inhibitors possess characteristics that meet many of the special needs of elderly patients, including reduction of left ventricular mass, lack of metabolic and lipid disturbances, no central nervous system effects, no risk of induction of cardiac failure, and low risk of orthostatic hypotension.

Aging↗
PubMed1992

Early occurrence of end-stage renal disease in a patient with infantile nephropathic cystinosis.

We report the case of a patient with infantile nephropathic cystinosis who required renal transplantation at age 30 months. Exhaustive evaluation did not identify a cause of progressive renal failure other than cystinosis. The patient's genetic lesion was allelic with those of other patients with cystinosis; fusion of this patient's fibroblasts with fibroblasts from another patient with infantile nephropathic cystinosis did not demonstrate complementation of the biochemical defect.

Clone Cells↗
PubMed1992

MIDAS: hypertension and atherosclerosis. A trial of the effects of antihypertensive drug treatment on atherosclerosis. MIDAS Research Group.

Although clinical trials of the efficacy of antihypertensive treatment have demonstrated impressive reductions in the incidence of stroke, the reduction in coronary artery disease mortality has been less impressive. It may be that the antihypertensive drugs used in these trials induced metabolic disturbances, or produced inadequate regression of left ventricular hypertrophy, thus blunting the reduction in risk of coronary artery disease expected with blood pressure-lowering. Isradipine, a dihydropyridine calcium antagonist known to be an effective antihypertensive agent, has also displayed pronounced antiatherogenic effects in animals. Thus, a reasonable hypothesis could be that isradipine not only reduces the level of blood pressure, but also may have a positive effect on the evolution of atherosclerotic plaque in coronary and carotid arteries, thereby leading to prevention of clinical sequelae of atherosclerosis. On this basis, a 3-year clinical trial is being carried out in the United States--the Multicenter Isradipine/Diuretic Atherosclerosis Study (MIDAS)--to establish the efficacy of isradipine in inhibiting atherogenesis and retarding the progression of atherosclerosis in carotid arteries of hypertensive patients. The primary end point of the study is intima-media thickness and the extent of atherosclerotic plaque in the carotid arteries, as measured by B-mode ultrasonography.

Antihypertensive Agents↗
PubMed1991

Steroid-dependent nephrotic syndrome following renal transplantation for congenital nephrotic syndrome.

A boy developed recurrent steroid-responsive nephrotic syndrome following renal transplantation for congenital nephrotic syndrome. The first episode was associated with mild tubulointerstitial rejection on kidney biopsy. Subsequent episodes showed normal histology by light microscopy and epithelial foot process fusion on electron microscopy, consistent with minimal change nephrotic syndrome. Serum analysis for soluble immune response suppressor was negative pre-nephrectomy, positive during each bout of nephrotic syndrome, and negative during each remission. This case represents de novo occurrence of steroid-sensitive minimal change nephrotic syndrome following renal transplantation for congenital nephrotic syndrome. We stress the need for histological examination of the renal allograft to diagnose rejection, recurrent disease, or de novo disease.

Child, Preschool↗
PubMed1991

Dose-response relationship of ramipril in patients with mild-to-moderate hypertension.

The dose-response relationship of ramipril was examined in 216 subjects with mild-to-moderate essential hypertension in a double-blind, placebo-controlled, multicenter study. Ramipril capsules (1.25, 2.5, 5, or 10 mg) or placebo capsules were administered once daily for 12 weeks. Significant reductions in supine and standing diastolic and systolic blood pressures were seen at end point in the ramipril 2.5, 5, and 10 mg treatment groups compared with placebo. The antihypertensive effect was greater at higher doses. The minimum effective dose of ramipril was 2.5 mg once daily.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1991

Control of interleukin 1 (IL-1) activity. I. Inhibition of IL-1 activity by soluble immune response suppressor (SIRS) in vitro.

Soluble immune response suppressor (SIRS), a nonspecific inhibitor of cellular and humoral immune responses and cellular proliferation, reversed IL-1-induced inhibition of autologous rosette formation by thymocytes. In addition, SIRS prevented the IL-1-induced increase in resistance of thymocytes to the lytic action of hydrocortisone. Kinetic experiments showed that the action of SIRS on thymocytes was rapid (less than 15 minutes), although a longer time was required to exert protective effects on thymocytes. SIRS also inhibited the stimulation of thymocyte proliferation induced by Con A and IL-1 a costimulatory assay of IL-1 activity. Moreover, SIRS inhibited the IL-1-stimulated expression of complement receptors on neonatal B cells. The inhibitory effects of SIRS were selectively directed towards IL-1, since SIRS did not interfere with induction of LAK cells by IL-2, and did not reverse inhibition of autologous rosette formation induced by factors other than IL-1, such as IL-4, a proline rich polypeptide and lactoferrin. The results presented in this report demonstrate that SIRS may be a selective inhibitor of IL-1 activity with respect to T and B cells, rendering them unresponsive to IL-1 activation and/or maturation signals.

Animals↗
PubMed1990

A regulatory system for soluble immune response suppressor production in steroid-responsive nephrotic syndrome.

Patients with nephrotic syndrome frequently have suppressed immune responses. Previously, it has been determined that subjects with steroid-responsive nephrotic syndrome (SRNS) produce the lymphokine, soluble immune response suppressor (SIRS). In the present group of experiments, a potential pathway of suppressor cell activation was investigated. Sera from patients with SRNS stimulated normal CD8+ lymphocytes to produce SIRS. Serum SIRS-inducing activity was abrogated by treatment with proteinase K or boiling, but was not affected by dialysis, acidification to pH 2, or heating to 56 degrees C. This serum factor could be distinguished functionally and antigenically from SIRS and from interferon (IFN) alpha or IFN gamma. Supernatants of cultured patient lymphocytes enriched for CD4+ cells were also found to activate normal CD8+ lymphocytes to produce SIRS. The lymphocyte-derived activity showed similar characteristics to those of the serum factor. Molecular weight of both factors was estimated to be 13,000 to 18,000 daltons by gel filtration chromatography, and activity of serum and lymphocyte supernatant from the same patients eluted with similar patterns on reversed-phase HPLC. These data suggest that serum SIRS-inducing activity is derived from a suppressor-inducer lymphocyte, and indicate the presence of a regulatory mechanism for SIRS production in steroid-responsive nephrotic patients.

Child↗
PubMed1990

The management of hypertension in older patients.

Hypertension need not be a natural consequence of aging; nevertheless, as many as 70% of individuals aged 70 years or more have diastolic blood pressures greater than or equal to 90 mm Hg and/or systolic blood pressures greater than 160 mm Hg. Well-controlled trials have documented significant reductions in cardiovascular mortality with treatment of diastolic elevation. Double-blind, long-term, open-label studies have been conducted of quinapril, a new angiotensin-converting enzyme (ACE) inhibitor, in 451 older patients compared with 1,887 younger patients. Results of these studies showed that quinapril is equally effective in older and younger patients. The studies also demonstrated that the safety of quinapril in the treatment of older patients is comparable with that in younger patients, in terms of both the incidence of adverse events and the types of adverse events reported. However, because many older patients have impaired renal function, which can prolong the half-life of renally excreted ACE inhibitors such as quinaprilat (the active metabolite of quinapril), they should be started on lower doses of quinapril (5 mg) than are used in younger patients. The shorter half-life and duration of action of quinaprilat compared with other once-daily ACE inhibitors may make quinapril better suited than these other agents for use in older patients.

Aged↗
PubMed1975

Double-blind studies of the clinical effectiveness of prazosin.

In separate double-blind trials, prazosin was compared with placebo and with methyldopa and placebo. In both, prazosin was well tolerated and succeeded in lowering blood pressure in patients with mild to moderate hypertension. The mean reductions with methyldopa were greater, but the difference was not statistically significant and a higher percentage of the patients in the prazosin group became normotensive.

Adult↗