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PubMed1981

[Fibrinolytic treatment of acute myocardial infarction (author's transl)].

Fibrinolytic treatment of acute myocardial infarction with streptokinase and urokinase has now been under investigation for almost 20 years. Initially encouraging reports of beneficial effects of streptokinase were not substantiated by carefully controlled studies performed on coronary care and intensive care units. Studies carried out during the last tne years were characterized by non-uniform trial conditions and results. Similarly, to date no clearly beneficial effects of urokinase could be established. In order to provide more concise analysis, the "European Cooperative Study Group for Streptokinase Treatment in Myocardial Infarction" conducted a multi-center controlled trial. Patients were allocated to risk-groups. Three-hundred fifteen patients with medium and high risk were randomized to a 24-hour infusion of streptokinase or glucose. The overall mortality within six months was significantly lower in the streptokinase group (p less than 0.01) contributed primarily by eight of the eleven centers. Only 13.5% of patients with myocardial infarction, however, were eligible for the study. Interpretation of the results yielded no indication of the nature of the fibrinolytic effects nor how the benefit could be explained pathophysiologically. Furthermore, it remains questionable whether systemically-administered streptokinase can lyse coronary thrombosis or reduce the size of myocardial necrosis. An indirect effect of streptokinase through lowering of blood viscosity and subsequently, peripheral capillary resistance may represent a theoretical possibility. the indication of routine systemic administration of streptokinase has not yet been established. Recent reports of promising results obtained by direct, intracoronary infusion of thrombolytic agents indicate that this alternative may lead to realization of a specific effect in reduction of coronary thrombosis and, consequently, myocardial necrosis.

Acute Disease↗
PubMed1979

Coronary-artery bypass surgery in stable angina pectoris: Survival at two years. European Coronary Surgery Study Group.

768 men aged under 65 with angina pectoris, at least 50% obstruction in two or more major vessels, and a left-ventricular ejection fraction greater than or equal to 0.5 took part in a prospective randomised trial of the effect of coronary-artery bypass on prognosis. 373 patients were alloted to medical and 395 to surgical treatment. There was no significant difference between the two groups in the distribution of variables recorded at the time of randomisation. 1. "surgical" patient was lost to follow-up. 26 "surgical" patients did not undergo surgery and 50 "medical" patients were operated on. All these 76 patients were retained in their original treatment groups for the analysis. At 2 years there was no significant difference in mortality between the two groups. A significant difference was, however, found in the subset of patients with three-vessel disease, survival being significantly better for surgical patients. Operative (in-hospital) mortality was 3.6% in all operated patients and 1.5% in the last third. On average, 1.9 grafts per patient were inserted in the two-vessel-disease subgroup and 2.4 grafts per patient in the three-vessel-disease subgroup. Graft-patency rate was 90% within 9 months and 77% between 9 and 18 months after surgery. Symptomatic improvement was significantly better and deterioration less in the surgical group.

Adrenergic beta-Antagonists↗
PubMed1984

Treatment allocation for nonlinear models in clinical trials: the logistic model.

Many clinical trials have a binary outcome variable. If covariate adjustment is necessary in the analysis, the logistic-regression model is frequently used. Optimal designs for allocating treatments for this model, or for any nonlinear or heteroscedastic model, are generally unbalanced with regard to overall treatment totals and totals within strata. However, all treatment-allocation methods that have been recommended for clinical trials in the literature are designed to balance treatments within strata, either directly or asymptotically. In this paper, the efficiencies of balanced sequential allocation schemes are measured relative to sequential Ds-optimal designs for the logistic model, using as examples completed trials conducted by the Eastern Cooperative Oncology Group and systematic simulations. The results demonstrate that stratified, balanced designs are quite efficient, in general. However, complete randomization is frequently inefficient, and will occasionally result in a trial that is very inefficient.

Biometry↗
PubMed1985

Treatment of locally unresectable cancer of the stomach and pancreas: a randomized comparison of 5-fluorouracil alone with radiation plus concurrent and maintenance 5-fluorouracil--an Eastern Cooperative Oncology Group study.

One hundred ninety-one patients with pathologically confirmed, locally unresectable adenocarcinoma of the stomach (57 patients) and pancreas (91 patients), were randomly allocated to therapy with 5-fluorouracil (5-FU) alone, 600 mg/m2 intravenously (IV) once weekly, or radiation therapy, 4,000 rad, plus adjuvant 5-FU, 600 mg/m2 IV, the first three days of radiotherapy, then follow-up maintenance 5-FU, 600 mg/m2, weekly. Forty-three patients (22%) could not be analyzed because of ineligibility or cancellation, thus 148 patients were evaluable. The median survival time was similar for both treatment programs and for both types of primary carcinoma, and was as follows: gastric primary carcinoma, 5-FU, 9.3 months; 5-FU plus radiotherapy, 8.2 months; pancreatic primary carcinoma, 5-FU, 8.2 months; 5-FU plus radiotherapy, 8.3 months. Substantially more toxicity was experienced by patients treated with the combined modality arm than by those patients receiving 5-FU alone. Severe or worse toxicity experienced by patients with gastric primary carcinoma treated by 5-FU was 19%, and the combined modality arm was 31%. The toxicity experienced by patients with pancreatic primary carcinoma treated with 5-FU was 27%, and the combined modality arm was 51%. Significant prognostic variables included: weight loss in stomach-cancer patients; and performance status, degree of anaplasia, and reduced appetite in pancreas-cancer patients.

Adenocarcinoma↗
PubMed1979

Research related to validation of treatment modalities by large-scale clinical trials.

The history of randomized, controlled, clinical trials is reviewed. Cooperative clinical trials are reviewed and summarized, and specific needs for future trials are identified. Improved policy on resource allocation decisions for clinical trials vs other forms of research is necessary, particularly as such trials begin to translate improved therapeutic knowledge into community level disease control.

American Heart Association↗
PubMed2005

Learned kin recognition cues in a social bird.

In many cooperatively breeding birds, kin selection has an important role in the evolution and maintenance of social behaviour, and 'helpers' can maximize indirect fitness gains by preferentially allocating care to close relatives. Although there is evidence for kin-biased helping behaviour in several species, the mechanism of kin recognition underlying this behaviour is poorly understood. Vocalizations are the most commonly used cues in avian recognition systems, but the effectiveness of vocal signals as reliable recognition cues must depend on how they are acquired. However, there have been no experimental studies of the development of vocal recognition cues in cooperative birds; indeed, the ontogeny of all bird vocalizations other than song is poorly known in any species. Here, we show that cooperatively breeding long-tailed tits (Aegithalos caudatus) can discriminate between kin and non-kin according to the individual-specific characteristics of contact calls, and show experimentally that individuals learn these calls from provisioning adults during the nestling period. Finally, we show that the pattern of cooperative behaviour in this species is consistent with the use of recognition cues learned through association.

Animals↗
PubMed1984

[Statistical standards for clinical long-term studies].

Interest in the implementation of long-term clinical studies has grown considerably in Austria in recent years, partly encouraged by studies of this nature performed in West Germany, Great Britain and the United States. However, such studies have to be based on biometric standards that must be adhered to in the planning, implementation and reporting phases of long-term studies if they are to be regarded as authoritative and to find international acceptance. The present paper deals with such standards, based on the current level of methodological development as well as the authors' experience gathered over many years of participation in such projects. Special emphasis is placed on planning, random sampling and analysis, randomization, documentation, organization, termination of studies, reporting, multicentre investigations and cooperation between doctors and statisticians. The authors present several alternatives with and without the use of computers, attempt to explain to clinicians the role of the biostatistician in the supervision of long-term studies and offer their services to those interested in their cooperation.

Austria↗
PubMed2000

From human-machine interaction to human-machine cooperation.

Since the 1960s, the rapid growth of information systems has led to the wide development of research on human-computer interaction (HCI) that aims at the designing of human-computer interfaces presenting ergonomic properties, such as friendliness, usability, transparency, etc. Various work situations have been covered--clerical work, computer programming, design, etc. However, they were mainly static in the sense that the user fully controls the computer. More recently, public and private organizations have engaged themselves in the enterprise of managing more and more complex and coupled systems by the means of automation. Modern machines not only process information, but also act on dynamic situations as humans have done in the past, managing stock exchange, industrial plants, aircraft, etc. These dynamic situations are not fully controlled and are affected by uncertain factors. Hence, degrees of freedom must be maintained to allow the humans and the machine to adapt to unforeseen contingencies. A human-machine cooperation (HMC) approach is necessary to address the new stakes introduced by this trend. This paper describes the possible improvement of HCI by HMC, the need for a new conception of function allocation between humans and machines, and the main problems encountered within the new forms of human-machine relationship. It proposes a conceptual framework to study HMC from a cognitive point of view in highly dynamic situations like aircraft piloting or air-traffic control, and concludes on the design of 'cooperative' machines.

Ergonomics↗
PubMed2000

Peer teaching and computer-assisted learning: An effective combination for surgical skill training?

BACKGROUND: The surgical literature suggests that collaborative learning using peers may be a valid way to teach surgical skills and there is a growing interest in the use of computer-assisted learning for this purpose. Combining this evolving technology with this type of teaching would theoretically offer a number of advantages including a reduction in the amount of faculty time devoted to this task. In this study, we evaluate the efficacy of a type of collaborative learning in a computer-assisted learning environment. MATERIALS AND METHODS: We designed a prospective, randomized study comparing novice learners who were allowed to work in pairs with those who worked independently in a specially equipped computer-assisted learning classroom. Both pretest and posttest assessments were performed by videotaping this skill. Three experts then evaluated the videotapes, in a blinded fashion. Three different outcomes were assessed. RESULTS: Seventy-seven subjects were enrolled in and completed the study. Comparison of the outcome measures demonstrated no between group difference in the average performance scores or posttest times. The proportion of subjects who correctly tied a square knot was significantly lower in the computer-assisted peer teaching group when compared with the computer-assisted learning alone group (P = 0.04). CONCLUSIONS: Collaborative learning in a computer-assisted learning environment is not an effective combination for teaching surgical skills to novices.

Computer-Assisted Instruction↗
PubMed1985

Beneficial effect of azathioprine and prediction of prognosis in primary biliary cirrhosis. Final results of an international trial.

The effect of azathioprine on survival of patients with primary biliary cirrhosis was studied prospectively in a multinational, double-blind, randomized clinical trial including 248 patients of whom 127 received azathioprine and 121 placebo. There were 57 deaths in the azathioprine group and 62 in the placebo group. The actual survival was slightly longer during azathioprine than during placebo treatment. Using Cox multiple regression analysis and adjusting for slight imbalance between the two treatment groups, the therapeutic effect of azathioprine was statistically significant (p = 0.01), with azathioprine reducing the risk of dying to 59% of that observed during placebo treatment (95% confidence interval 40%-90%) or improving survival time by 20 mo in the average patient. Furthermore, azathioprine slowed down progressing incapacitation. Side effects of azathioprine were relatively few. The analysis revealed that the following five variables independently implied poor prognosis: high serum bilirubin, old age, cirrhosis, low serum albumin, and central cholestasis. These factors were combined to a "prognostic index" for prediction of outcome in new patients. The index was validated on independent patient data. On the basis of these results we recommend azathioprine as a routine treatment of primary biliary cirrhosis.

Actuarial Analysis↗
PubMed1994

From the editors.

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Age Factors↗
PubMedDate not supplied

The chosen.

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Decision Making↗
PubMed2005

[Do the Japanese drink less alcohol than other peoples?: the finding from INTERMAP].

It has been pointed out that Japanese men drink more than American and British men. In this presentation, we report the comparison of drinking habits from the findings of the International Study of Macro-nutrients and Blood Pressure (INTERMAP) conducted during 1997-99 in Japan, China, the United States of America (U.S.), and the United Kingdom (U.K.). INTERMAP was conducted with highly standardized procedures including dietary assessment, blood pressure measurement and questionnaires to clarify and compare their relationship in randomly selected 4680 men and women aged 40-59 years from 17 centers in the four countries. For alcohol drinking habits, four times of 24-hour dietary recall studies and two times of one-week recall studies were conducted. The drinking prevalence of Japanese men was the highest among the four countries. For women, it was also higher than in U.S. but lower than in U.K. Abstinence rates in U.S. were extremely higher than those of Japanese (19, 20% vs. 1, 4% in men and women, U.S. vs. Japan, respectively). Japanese men consumed the average of 27 g per day of alcohol and it was the highest among the populations. Energy intake from alcohol per total energy intake was also the highest in Japanese men. Health professionals in Japan need to recognize from the findings of INTERMAP and other studies such as INTERSALT that Japanese men drink more alcohol than Americans and British counterparts.

Adult↗