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Biomedical subjects

J M Long

Publications and source records attributed to J M Long.

At least 55 records · Page 3Linked to original sources
PubMed1988

Predictors of total and low-density lipoprotein cholesterol change after partial ileal bypass.

POSCH is a prospective, randomized secondary intervention trial examining the effect of maximal lipoprotein modification achieved by partial ileal bypass on overall mortality and the course of coronary heart disease. In the initial 189 surgical patients, total cholesterol levels decreased from 256.7 +/- 2.6 mg/dl to 166.6 +/- 2 mg/dl, and low-density lipoprotein cholesterol levels decreased from 181.5 +/- 2.7 mg/dl to 94.1 +/- 1.7 mg/dl 3 months after operation. These significant decreases were sustained through 5 years of follow-up (p less than 0.001). The total cholesterol level was 29.2 +/- 0.9 percent lower and the low-density lipoprotein cholesterol level was 43.2 +/- 1 percent lower at 5 years compared with the baseline level. Decreases of similar magnitude were seen in each of the common WHO lipoprotein phenotypes. The baseline total cholesterol level was the only significant independent preoperative predictor of the 5 year total cholesterol level (correlation coefficient 0.547; p less than 0.001), and the baseline low-density lipoprotein cholesterol level was the only significant independent preoperative determinant of the 5 year low-density lipoprotein cholesterol level (correlation coefficient 0.599; p less than 0.001). These relationships are expressed by the following equations: 5 year total cholesterol = 0.54 X baseline total cholesterol + 42.3, and 5 year low-density lipoprotein cholesterol = 0.455 X baseline low-density lipoprotein cholesterol + 19.2. The decrease in total and low-density lipoprotein cholesterol levels after partial ileal bypass are greater than reported by any trial of drug or diet intervention, including the Lipid Research Clinics Coronary Primary Prevention Trial which examined cholestyramine. Estimation of the change in total and low-density lipoprotein cholesterol levels after partial ileal bypass can be made based on preoperative lipid analysis and is essential in comparing different therapeutic modalities and assessing the role of partial ileal bypass among strategies aimed at lowering coronary heart disease risk.

Adult↗
PubMed1987

Program on Surgical Control of the Hyperlipidemias (POSCH): recruitment experience.

The Program on Surgical Control of the Hyperlipidemias (POSCH) is an investigator-initiated NHLBI grant-funded secondary coronary heart disease intervention trial using partial ileal bypass (PIB) for lipid reduction. Randomization started in September 1975 and ended in July 1983 with enrollment of 838 participants (421 surgery, 417 controls). The trial is scheduled to reveal the atherosclerosis impact of the lipid changes in 1990, at which time the average individual in the program will have been followed for 9.6 years. Initially, the magnitude of the recruitment task was greatly underestimated. An area containing 500,000 people was judged to be sufficient to randomize one patient per month. Actually, a population of 2.4-10.5 million, depending upon proximity to a clinic, was needed to achieve this goal. The study design was changed in 1981, due to recruitment costs, with reduction of the number of individuals to be randomized from 1000 to 838 and with extension of the duration of minimum follow-up from 5 to 7 years. Only with the development of a uniform model clinic concept, with specified levels of performance calculated from actual recruitment data, did accrual of patients into the trial become predictable and achievable. Some of the recruitment delays in POSCH were related to problems, in part generic to the existent grant funding mechanism and associated with decisions made by NHLBI and its Advisory Council. These delays were manifested by denial of reallocation of approved funds to initiate replacement clinics for discontinued ones, an 18-month delay in implementation of a protocol change in lipid criteria suggested by the Data Monitoring Committee, and a 2-year delay in the starting date for the fourth active clinic.

Adult↗
PubMed1987

An example of expert systems applied to clinical trials: analysis of serial graded exercise ECG test data.

Clinical trials collect large amounts of data over time. The use of statistical methods to compare and interpret these serial data often fall short of complete evaluation because the analysis requires clinical judgment. As an alternative, some trials use individual experts or panels of experts to evaluate data, but this method usually requires the participation of clinicians who must spend large amounts of time performing tedious, repetitive tasks. The authors examined the use of expert systems to analyze serial clinical trial data where the analyses required use of clinical judgment. A prototype expert system was built to assess the data obtained from a pair of serial graded exercise ECG tests and reach a decision that would duplicate the decision reached by a cardiologist. The experiment was successful. Expert systems should be further developed and tested in other areas, such as serial coronary arteriography data.

Clinical Trials as Topic↗
PubMed1987

Lipoprotein modification achieved by partial ileal bypass: five-year results of The Program on the Surgical Control of the Hyperlipidemias.

The Program on the Surgical Control of Hyperlipidemias (POSCH) is a multicentered, randomized, secondary intervention trial assessing the effect of lipoprotein modification achieved by partial ileal bypass (PIB) on overall mortality rates and the course of coronary heart disease. Of the 838 participants, 396 (196 control and 200 surgical patients) have complete 5-year lipoprotein results and are the basis of this report. After PIB, total cholesterol level decreased 24 +/- 1.2% (mean +/- SEM) and low-density lipoprotein cholesterol level fell 38 +/- 1.5% in comparison with control subjects. High-density lipoprotein (HDL) cholesterol level was not changed by PIB; however, a significant decrease in HDL occurred over 5 years in the control group (41.7 +/- 0.7 mg/dl versus 39.5 +/- 0.6 mg/dl, p less than 0.05). This led to consistently higher HDL levels in the surgical group in comparison with control subjects after PIB. Very low-density lipoprotein cholesterol and triglyceride levels were higher in the surgery group than in control subjects (24 +/- 7.6% and 21 +/- 5.4% at 5 years). Apolipoprotein B-100 was significantly lower, and apolipoprotein A-I and HDL-2 were significantly higher in the surgery group. These lipoprotein changes are greater than have been reported from any previous trial of dietary or pharmacologic intervention, including the Lipid Research Clinics-Coronary Primary Prevention Trial, which used cholestyramine. Based on available epidemiologic data, these changes predict a marked reduction in morbidity and mortality rates associated with coronary heart disease after PIB.

Adult↗
PubMed1986

The POSCH data processing experience. The problem of metadata.

Metadata, the term, may be new but metadata, the concept, is not new. For purposes of this paper, the term metadata is defined as the data used to define, store, retrieve, combine, analyze, and present the data values (the "real" data, so to speak). As clinical research studies get larger, it becomes desirable to use automated managers of the metadata. The Program on the Surgical Control of the Hyperlipidemias (POSCH), a national multiclinic clinical trial, manages most of its metadata manually but has been experimenting with ways to more fully automate them. Its Information Management System (IMS) is described with special emphasis on how it manages the metadata. The case is presented for further automation and standardization of metadata in large clinical research studies so that costs can be contained and smaller increments of "progress" can be measured. The concept of a Metadatabase Management System (MDBMS) is developed and illustrated using POSCH.

Arteriosclerosis↗
PubMed1985

Nutritional assessment indications of postburn complications.

This study evaluates the use of nutritional assessment indexes measured on the fifth day after injury to predict subsequent wound infections, episodes of septicemia, and other infectious complications in burned patients. Nutritional assessment data collected included anthropometric measurements (weight, height, triceps skinfold, and upper-arm circumference); biochemical testing (serum albumin concentration, serum transferrin concentration, total lymphocyte count, creatinine/height index, and nitrogen balance); and recall skin antigen testing. Seventy-four adult patients (mean age of 35 years) who had burn injuries ranging from 10% to 96% total body surface were studied. Indexes predictive of imminent wound infection include serum transferrin concentrations less than 150 mg/dl (p = .0006) and anergy to the skin test battery (p = .01). Those indexes were also prognostic of the development of septicemia (p = .0002 and p = .0001, respectively). Although statistically insignificant, total lymphocyte count also showed a similar trend toward predicting complications. Serum albumin concentration (less than 3.0 gm/dl), creatinine/height index (less than 60% standard), percent ideal body weight (less than 80%), percent weight change, and nitrogen balance did not contribute to group discrimination. Severe depletion of the visceral protein compartment was documented in a large percentage of patients on the fifth postburn day. Serum transferrin concentration and recall skin antigen testing can be helpful in identifying thermally injured patients who are at high risk of infectious complications.

Adolescent↗
PubMed1982

The effect of status on blood pressure during verbal communication.

Blood pressures and heart rates of 40 subjects were recorded at 1-min intervals over 35 min during which subjects engaged in a variety of verbal activities with either a high-status or an equal-status experimenter. All subjects showed statistically significant increases in blood pressure and heart rate when speaking compared to when quiet. Blood pressure increases during speaking of the 20 subjects exposed to a high-status experimenter were significantly greater than those of subjects exposed to an equal-status experimenter. While the blood pressure increase was related partly to the act of speaking, the amount of increase was also related to the social distance between experimenter and subject. The results are discussed relative to behavioral interventions for the treatment of hypertension.

Adult↗
PubMed1982

Interpersonal aspects of blood pressure control.

Recent observations of large, consistent increases in blood pressure during human communication prompted a reassessment of the role of interpersonal factors in the behavioral control of hypertension. It was noted that the conceptual framework around which earlier behavioral studies have been carried out, as well as in the physical methods of pressure determination themselves, have contributed to a general lack of information about the role of interpersonal interactions in hypertension. An awareness of the relationship between speaking and pressure elevations has led to the development of a new conceptual approach to understanding the etiology and treatment of hypertension. Using techniques developed out of transactional psychophysiology, hypertensive patients have been able to observe the importance of interpersonal communications in the regulation of their own blood pressure. Evidence from the clinical use of such information suggests that a new way can be developed to help patients lower their blood pressure.

Behavior Therapy↗
PubMed1982

Automated blood pressure recording: the phenomenon of blood pressure elevations during speech.

The recent development of automatic non-invasive blood pressure devices has allowed the rapid and repeated assessment of both the blood pressure and pulse rate in the clinical setting. The development of this technology has allowed us to observe a striking relationship between human communication and blood pressure. Talking produces rapid increases in their systolic, diastolic and mean arterial pressures as well as pulse rate in both normotensive and hypertensive subjects. This phenomenon has been obscured by the conventional assessment techniques of blood pressure measurement. Ignoring the pattern of verbal communication during the assessment of blood pressure can result in marked differences in recorded blood pressure and its interpretation.

Adult↗
PubMed1982

The Program on the Surgical Control of the Hyperlipidemias: a status report.

The Program on Surgical Control of the Hyperlipidemias (POSCH) is a multicentered secondary coronary heart disease intervention trial utilizing maximal plasma lipid reduction as achieved by the partial ileal bypass operation. With over 500 patients recruited into this trial at present, the 4-year sequential lipid changes are statistically highly significant and include an approximate 30% plasma total cholesterol and 40% low density lipoprotein (LDL)-cholesterol reduction, with a slight increase in the high density lipoprotein (HDL)-cholesterol and a marked increase in the HDL-cholesterol:LDL-cholesterol ratio of about 75% or higher. A definitive answer to the lipid-atherosclerosis theory corollary--whether a decrease in the plasma cholesterol engenders a reduction in the incidence or severity of atherosclerotic cardiovascular disease--can be expected from these marked lipid changes in POSCH.

Adult↗
PubMed1982

Blood pressure changes while talking.

Using a noninvasive automatic device to rapidly and repeatedly measure blood pressure, a striking relationship was found between talking and an increase in blood pressure and heart rate. This finding was demonstrated in a variety of experimental settings (the laboratory, medical clinic, classroom and home) in both children and adults and in both normotensive and hypertensive individuals. A significant positive correlation was also observed between the level of resting pressure and the magnitude of increase in pressure while talking. These findings point toward an important link between human communication and blood pressure control that has previously been overlooked. They also suggest a new conceptual approach to the understanding and treatment of hypertension.

Adolescent↗
PubMed1981

The effects of talking on the blood pressure of hypertensive and normotensive individuals.

The use of a recently developed noninvasive automated blood-pressure device has revealed a striking relationship between human communication and elevations in blood pressure in both normotensive and hypertensive individuals. Individuals with higher resting baseline pressures tended to show greater increases during talking than did those with lower pressures. In some hypertensive individuals increases blood pressure greater than 25-40% occurred within 30 sec after the initiation of human speech. Links between difficulties surrounding human communication and elevations in blood pressure are discussed.

Adult↗
PubMed1980

Cultural determinants of achievement, aggression, and psychological distress.

We present a cross-cultural exploration of the interrelationships among six concepts: achievement (ie, cultural attainment), aggression, psychological distress, competition, interpersonal intensity (strength of passionate attachments), and social synergy (patterned behavior that simultaneously benefits both individual and society). Of interest is the proposition that levels of achievement, aggression, and psychological distress are partly determined by corresponding levels of competition and interpersonal intensity; however, in the presence of high levels of social synergy, aggression and psychological distress are lowered without affecting the level of achievement. We have tested the implied linear relationships, using blind ratings (of five variables assessed from ethnographic extracts) obtained from ten cross-cultural scholars, and a Social Development Index (from Tatje and Naroll) to indicate achievement. A sample of 58 societies was employed in correlation and multivariate analysis of variance.

Achievement↗
PubMed1980

The POSCH Information Management System: experience with alternative approaches.

An unconventional approach to the information management system for a clinical trial is presented in this paper: employment of a large shared computer utility, use of existing packaged software, and use of a generalized data base management system. An easily maintained system was developed at a very economical cost. The paper is designed to present our experiences and include descriptions of a series of problems that were faced and solved: design problems, problems with error corrections, and problems unique to our operational procedures. The good results are due as much to careful management as to the initial decision to use the unconventional approach. Special attention has been paid to cost controls, patient safety, and data security. The approach has been successful, and others are encouraged to consider a similar approach.

Clinical Trials as Topic↗