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Biomedical subjects

H W Schnaper

Publications and source records attributed to H W Schnaper.

At least 91 records · Page 5Linked to original sources
PubMed1987

Background and design of the new U.S. trial on diet and drug treatment of "mild" hypertension (TOMHS).

A multicenter, randomized, controlled, double-blind U.S. trial is comparing the combined effects of diet treatment and 1 of 5 active drug regimens with diet treatment alone, for the long-term management of middle-aged adults with "mild" hypertension. Factors stimulating this trial are data documenting the high prevalence of mild hypertension in the adult population; mild hypertension's responsibility for a high proportion of morbidity and mortality attributable to hypertension overall; data from long-term hypertension intervention trials showing reduced morbidity and mortality of people with mild hypertension with use of either diuretics or beta blockers as step-1 therapy, and other trials that failed to demonstrate beneficial impact on morbidity and mortality, possibly due to residual questions concerning aspects of benefit to risk ratios with these medications; recent data from trials showing long-term control of mild hypertension and other risk factors by nutritional means; lack of data from long-term trials on benefit to risk ratios with newer drugs such as selective alpha 1 inhibitors, angiotensin converting enzyme inhibitors and calcium channel blockers; paucity of data from trials on long-term combined effects of diet and drug therapy, and of diet alone, for people with mild hypertension. During the next few years, phase 1 of the trial will study 6 groups of drugs. The step-1 drugs are angiotensin converting enzyme inhibitor (enalapril), alpha 1 inhibitor (doxazosin), beta blocker (acebutolol), calcium channel blocker (amlodipine), diuretic (chlorthalidone) and placebo. All participants are to receive vigorous sustained nutritional counseling to reduce obesity, moderate sodium intake and avoid heavy use of alcohol. Key endpoints for phase 1 of the study are the need for additional medication to control mild hypertension, side effects (i.e., clinical and biochemical) and consequent need to discontinue drug and quality of life. Phase-1 data are to be used to complete the phase-2 design, with the ultimate aim to assess effects on morbidity and mortality.

Adult↗
PubMed1987

Immunology.

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Humans↗
PubMed1987

Prolonged survival in a child with renovascular hypertension from abdominal-pulmonary Takayasu's arteritis.

Takayasu's disease is an inflammatory condition of the large arteries which comprises circulation to the head, extremities, and, less often, the abdominal viscera or lungs. A 10-year-old girl with renovascular hypertension secondary to Takayasu's arteritis has been followed for over 5 years. Her course is unusual in that (1) her disease is not related to tuberculosis; and (2) despite a persistently active disease course, she has been allowed to experience a fairly normal life-style through continued, extensive medical and surgical management. Vascular involvement has been documented by digital subtraction angiography; less invasive techniques were not useful for monitoring disease progression.

Child↗
PubMed1987

Immunology.

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Glomerulonephritis↗
PubMed1987

Comparison of enalapril and thiazide diuretics in the elderly hypertensive patient.

One hundred seventy-four patients, 65 years of age or older, entered a double-blind, seven-center, 16-week, controlled study to compare the effects of enalapril and hydrochlorothiazide (HCTZ) in an elderly hypertensive population. Sixty-eight percent of the patients were men, 32% were women. Thirty-two percent of the patients had isolated systolic hypertension. Approximately 80% of the patients were white. After a 4-week placebo run-in period, patients with sitting diastolic BP (DBP) of 90-120 mm Hg or systolic BP (SBP) greater than or equal to 160 mg Hg and DBP less than 90 mm Hg (isolated systolic hypertension) were randomized to receive 10 mg of enalapril or 12.5 mg of HCTZ once daily. If after 4 weeks their BPs were not controlled (i.e., DBP greater than 85 mm Hg or SBP greater than 140 mm Hg), the dose of the drug was doubled. If after successive 4-week intervals, their BPs were still not controlled, the other drug was added to their regimen and this was then doubled. The initial mean BPs were 167/94 mm Hg in both groups. By the end of the monotherapy phase at 8 weeks, the mean BPs had fallen significantly (p less than or equal to 0.01) to 148/85 mm Hg in both groups. By 16 weeks, the mean BPs had again fallen similarly: in the enalapril group to 144/83 mm Hg, and in the HCTZ group to 145/83 mm Hg. Seventy-nine percent of the enalapril group and 85% of the HCTZ group had controlled BPs at this time (DBP less than or equal to 85 or SBP less than or equal to 140 mm Hg). White and nonwhite patients in both drug groups had similar falls in SBP and DBP both at the end of the monotherapy period and the overall study. The white patients experienced more rapid falls in BP with enalapril, the nonwhite patients with HCTZ. Three serious adverse experiences occurred in the enalapril group, none of which were considered likely to be due to the drug therapy. Overall, 49% of the enalapril group and 61% of the HCTZ group reported an adverse effect during the study (not significant). Laboratory adverse effects occurred 10% more frequently in the HCTZ group: enalapril, 22%; HCTZ, 32% (not significant); none was serious. Both drugs therefore appeared to be equally efficacious antihypertensive agents in these elderly patients.

Aged↗
PubMed1987

Steroid-sensitive mechanism of soluble immune response suppressor production in steroid-responsive nephrotic syndrome.

Soluble immune response suppressor (SIRS), a lymphokine that suppresses antibody production and delayed type hypersensitivity in vivo, has been detected in urine and serum from certain patients with nephrotic syndrome. In the present paper, the relationship between SIRS production and nephrotic syndrome is further characterized. A striking correlation was found between detection of SIRS and the presence of steroid-responsive nephrotic syndrome (SRNS). A potential mechanism of SIRS production in SRNS patients was identified, in that lymphocytes from patients produced SIRS without requiring activation by exogenous agents, and incubation of normal lymphocytes with serum from patients activated the cells to secrete SIRS in culture. Although SIRS disappears rapidly from urine or serum after initiation of corticosteroid therapy, hydrocortisone (10(-6)-10(-7) M) did not block secretion of SIRS by activated suppressor cells. It did, however, inhibit in vitro activation of lymphocytes to produce SIRS by concanavalin A, interferon, or SRNS patient serum. The association of suppressor cell activation with SRNS and the sensitivity of both to steroids suggest that the pathogeneses of albuminuria and SIRS production are related.

Antigen-Antibody Reactions↗
PubMed1986

Suppression of immune responses to sheep erythrocytes by the lymphokine soluble immune response suppressor (SIRS) in vivo.

Soluble immune response suppressor (SIRS) is a protein produced by activated suppressor T lymphocytes which inhibits division by tumor cells and plaque-forming cell (PFC) responses in vitro. Although this lymphokine has been fairly well characterized in vitro, little is known about its effects in vivo. Purified murine SIRS, 10(3) to 10(4) U injected i.p., suppressed murine PFC responses to sheep erythrocytes (SRBC) in vivo. Suppression occurred when SIRS was injected into mice 5 days before assay, and also occurred when SIRS activated with 10(-6) M H2O2 was injected 24 hr before assay. These kinetics are similar to those observed in tissue culture, where suppression of PFC responses requires the addition of SIRS 4 to 5 days before assay unless SIRS is activated to SIRSox by H2O2. Levamisole, an inhibitor of SIRS-mediated suppression in vitro, also blocked suppression by SIRS in vivo. Delayed-type hypersensitivity reaction to footpad injection of SRBC was also inhibited by SIRS. Suppression of PFC responses by recombinant immune interferon (IFN-gamma), which activates lymphocytes to produce SIRS in vitro, was blocked by injection of levamisole or monoclonal anti-SIRS antibodies. These results show that SIRS suppresses immune responses in vivo, and suggest that suppression of PFC responses by IFN-gamma may be largely mediated by SIRS. These findings indicate that SIRS could contribute to the development of suppressed immunity in vivo.

Animals↗
PubMed1986

Use of diuretics in treatment of hypertension in the elderly.

Men and women with isolated systolic hypertension who were at least 60 years of age were treated for 1 year with chlorthalidone (25-50 mg daily) or matching placebo as the step I drug. Most patients reached goal blood pressure without requiring a step II drug. The blood pressure response was similar in all age, sex and race subgroups, with an overall difference between the randomised groups of 17 mm Hg for systolic blood pressure (p less than 0.001) and 6mm Hg for diastolic blood pressure (p less than 0.001). The only common adverse effects were asymptomatic changes in the serum concentrations of potassium (0.5 mmol/L lower in the chlorthalidone group, p less than 0.001), uric acid (0.9 mg/dl higher, p less than 0.001), and creatinine (0.08 mg/dl higher, p = 0.02). Compliance was good, and more than 80% of participants were still taking the study medications at the end of the year.

Aged↗
PubMed1986

Reflections on the pediatric chief residency.

The chief residency in pediatrics, with its variety of functions, can be both a rewarding and trying experience. The author conducted two surveys of pediatric chief residents, which were taken at the beginning and end of their terms, in order to gauge how various educational, interpersonal, and clinical factors changed in importance during the course of their residencies. From these findings and from his own personal experiences, the author offers ways to improve the quality of a chief resident's tenure.

Internship and Residency↗
PubMed1986

Systolic Hypertension in the Elderly Program, Pilot Study (SHEP-PS): morbidity and mortality experience.

SHEP-Pilot Study, a randomized, double-blind, placebo-controlled trial of drug therapy for isolated systolic hypertension, followed 551 participants aged 60 years or more with untreated blood pressures of greater than or equal to 160/less than 90 mmHg for an average of 34 months. Mean age was 72 years, 63% were female and 82% white. Pretreatment blood pressures averaged 172/75 mmHg. As their Step I drug, 443 participants were assigned chlorthalidone and 108 placebo. Of 512 surviving participants, 80% and 84% of the chlorthalidone and placebo groups, respectively, attended their last clinic visit; 71% and 60% were still taking blinded drug; and 60% and 33% had systolic blood pressures less than 160 mmHg. Final blood pressures averaged 140/67 and 154/72 mmHg for the chlorthalidone and placebo groups, respectively. All-cause mortality rates were 25 and 23 deaths per 1000 participant-years of risk, respectively; rates for 'definite' first strokes were 8.3 and 13 deaths. Differences between chlorthalidone and placebo groups were significant for blood pressure but not for event rates.

Aged↗
PubMed1985

Systolic Hypertension in the Elderly Program (SHEP): antihypertensive efficacy of chlorthalidone.

The Systolic Hypertension in the Elderly Program (SHEP) is a randomized, blinded test of the efficacy of antihypertensive drug treatment. In a large feasibility trial, 551 men and women who had isolated systolic hypertension and were at least 60 years old received chlorthalidone (25 to 50 mg/day) or matching placebo as the step I drug. After 1 year, 83% of the chlorthalidone group and 80% of the placebo group were still taking SHEP medications. Of those still taking chlorthalidone, 88% had reached goal blood pressure (BP) without requiring a step II drug, and most had responded to the lower dose (25 mg/day). The BP response was similar in all age, sex and race subgroups, with an overall mean difference between randomized groups of 17 mm Hg for systolic BP (p less than 0.001) and 6 mm Hg for diastolic BP (p less than 0.001). The only common adverse effects were asymptomatic changes in the serum levels of potassium (0.5 mEq/liter lower in the chlorthalidone group, p less than 0.001), uric acid (0.9 mg/dl higher, p less than 0.001) and creatinine (0.08 mg/dl higher, p = 0.02). This study indicates that chlorthalidone is effective for lowering BP in elderly patients with systolic hypertension and sets the stage for a larger trial of the effects of such treatment on the incidence of cardiovascular disease.

Aged↗
PubMed1985

Identification of the lymphokine soluble immune response suppressor in urine of nephrotic children.

Patients with minimal change nephrotic syndrome (MCNS) frequently have suppressed in vivo and in vitro immune responsiveness of uncertain etiology. Because increased suppressor cell activity has been associated with this disease, urines from MCNS patients were screened for activity of the lymphokine soluble immune response suppressor (SIRS), a product of concanavalin A- or interferon-activated suppressor T cells. Urines from untreated MCNS patients suppressed polyclonal plaque-forming cell responses of cultured splenocytes. This suppressive activity was identified as human SIRS by the following functional and physical criteria: molecular weight estimated by gel filtration; kinetics of suppression; inhibition of suppression by catalase, levamisole, and 2-mercaptoethanol; abrogation of activity by acid or protease treatment; elution pattern on high performance liquid chromatography; and cross-reactivity with monoclonal antimurine SIRS antibodies. Suppressive activity disappeared from urine after initiation of treatment but before remission of symptoms. Urines were tested from 11 patients with MCNS, all of whom excreted SIRS. In addition, two nephrotic patients with acute glomerulonephritis and three nephrotic patients with membranoproliferative disease excreted SIRS, but other nephrotics and all nonnephrotic patients did not. These results indicate that excretion of SIRS occurs in certain cases of nephrotic syndrome and that the presence of SIRS in the urine is not accounted for solely by the presence of proteinuria or nephrosis. Serum from four nephrotic patients also contained SIRS, whereas neither serum nor urine from six normal subjects contained SIRS activity. The systemic presence of SIRS in these four patients, and the identification of SIRS in urines from a larger group of patients, suggest a possible role for SIRS in the suppressed immune responses often found in nephrotic syndrome.

Adolescent↗
PubMed1985

Cystinosis presenting with features suggesting Bartter syndrome. Case report and literature review.

Features suggestive of Bartter syndrome (hypokalemia, hypochloremic metabolic alkalosis, and normal blood pressure despite hyperreninemia and hyperaldosteronism) were found in a 5-year-old black child with cystinosis and Fanconi syndrome. Review of his medical records revealed that these abnormalities had probably been present when he first became clinically ill at 2 years of age. Sodium and potassium chloride supplementation lead to improved growth and strength, partial correction of his electrolyte abnormalities, and a decrease in markedly elevated plasma renin activity. Literature review disclosed a similar presentation in four Caucasian children with cystinosis. Biochemical findings compatible with Bartter syndrome can occur together with evidence of generalized proximal renal tubular dysfunction (Fanconi syndrome) in nephropathic cystinosis.

Anemia, Aplastic↗
PubMed1984

Identification and initial characterization of concanavalin A- and interferon-induced human suppressor factors: evidence for a human equivalent of murine soluble immune response suppressor (SIRS).

Human suppressor T cells activated by leukocyte interferon have properties similar to murine suppressor cells activated by interferon or by concanavalin A. Murine suppressor cells release a soluble mediator, soluble immune response suppressor (SIRS), which accounts, at least in part, for suppressive activity in murine systems. To compare and contrast murine and human suppressor pathways, we evaluated the suppression of human polyclonal plaque-forming cell responses by concanavalin A, by leukocyte interferon, and by immune interferon, or by suppressor cells activated by these agents. In each instance, suppressive activity was prevented by levamisole, ascorbic acid, catalase, or 2-mercaptoethanol, agents known to interfere with murine SIRS activity. Furthermore, concanavalin A, immune interferon, and leukocyte interferon induced T lymphocytes to release 110,000 to 150,000 m.w. proteins which suppressed responses only when added early in the culture period. As with murine SIRS, suppression by each of these human factors was inhibited by 2-mercaptoethanol, ascorbic acid, catalase, or levamisole. The reaction of human suppressor factors with H2O2 (10(-6) M) activated suppressor factors so that they suppress responses when added late in the culture period. Human suppressor factors were protease- and acid (pH 2)-sensitive. The similarities between these human suppressor factors and murine SIRS show the existence of a human SIRS pathway.

Animals↗
PubMed1983

Protective effects of aspirin against acute myocardial infarction and death in men with unstable angina. Results of a Veterans Administration Cooperative Study.

We conducted a multicenter, double-blind, placebo-controlled randomized trial of aspirin treatment (324 mg in buffered solution daily) for 12 weeks in 1266 men with unstable angina (625 taking aspirin and 641 placebo). The principal end points were death and acute myocardial infarction diagnosed by the presence of creatine kinase MB or pathologic Q-wave changes on electrocardiograms. The incidence of death or acute myocardial infarction was 51 per cent lower in the aspirin group than in the placebo group: 31 patients (5.0 per cent) as compared with 65 (10.1 per cent); P = 0.0005. Nonfatal acute myocardial infarction was 51 per cent lower in the aspirin group: 21 patients (3.4 per cent) as compared with 44 (6.9 per cent); P = 0.005. The reduction in mortality in the aspirin group was also 51 per cent--10 patients (1.6 per cent) as compared with 21 (3.3 per cent)--although it was not statistically significant; P = 0.054. There was no difference in gastrointestinal symptoms or evidence of blood loss between the treatment and control groups. Our data show that aspirin has a protective effect against acute myocardial infarction in men with unstable angina, and they suggest a similar effect on mortality.

Adrenergic beta-Antagonists↗
PubMed1983

Cerebral cortical atrophy in pediatric patients with end-stage renal disease.

Computed tomography of the head in 15 children with end-stage renal disease revealed cerebral cortical atrophy in eight and ventricular enlargement in an additional two. These changes were not necessarily associated with any clinical signs or symptoms. Although high doses of steroids may have been responsible for some of the lesions, alternate etiologies are required to explain the abnormality in others cases. The mean length of time the patients received chronic hemodialysis was twice as long in patients with atrophy as in those with normal scans. However, possible causative factor/s related to dialysis could not be identified. The high incidence of cerebral atrophy is cause for concern and indicates the need for further study of this phenomenon.

Adolescent↗
PubMed1983

Suppressor T cell activation by human leukocyte interferon.

Murine fibroblast interferon (IFN beta) activates murine suppressor T lymphocytes in vitro, which suppress plaque-forming cell responses by spleen cells. Suppression of human in vitro immune responses by IFN was investigated to determine whether human IFN also activates suppressor T cells. Human leukocyte IFN (IFN alpha) suppressed pokeweed mitogen-induced polyclonal immunoglobulin production by human peripheral blood mononuclear cells (PBMC) by 80 to 90% at doses of 200 to 350 U/ml. Responses by IFN alpha-treated PBMC were suppressed in a dose-dependent manner; control cultures had maximal responses on day 7. PBMC incubated with 10,000 U/ml of IFN alpha contained activated suppressor cells that decreased pokeweed mitogen-stimulated, polyclonal immunoglobulin production by autologous cells by 70 to 80%. Suppression mediated by these cells was prevented by catalase, ascorbic acid, and 2-mercaptoethanol (2-ME). In murine systems, these reagents interfere with expression of suppressor T cell activity by preventing activation of soluble immune response suppressor. Selection procedures with monoclonal antibodies identified the suppressor cell as an OKT8+ (suppressor/cytotoxic) T lymphocyte. Selected OKT8+ cells required less IFN alpha (1000 U/ml) for activation and were effective in smaller numbers than unfractionated activated PBMC. IFN alpha-activated suppressor cells also inhibited proliferation in mixed lymphocyte and mitogen-stimulated PBMC cultures; again, catalase and 2-ME blocked suppression. These results indicate that IFN alpha activates suppressor T cells in human PBMC cultures; the ability of catalase, 2-ME, and ascorbic acid to block suppression suggests that these suppressor T cells have certain similarities to IFN beta or to concanavalin A-activated murine suppressor T cells.

Animals↗