Showing papers by "University of Vermont published in 1991"

National survey of problems and competencies among four- to sixteen-year-olds: parents' reports for normative and clinical samples.

Abstract: We compared parent-reported problems and competencies for national samples of 2,600 4-16-year-olds assessed at intake into mental health services and 2,600 demographically matched nonreferred children assessed in a home interview survey. Parents responded to the ACQ Behavior Checklist, which includes 23 competence items, three competence scales, 216 problem items, eight syndrome scales, Internalizing, Externalizing, and total competence and problem scores. Most items and scales discriminated significantly (p less than .01) between referred and nonreferred samples. There were important sex and age differences in problem patterns, but regional and ethnic differences were minimal. Somewhat more problems and fewer competencies were reported for lower- than upper-socioeconomic-status children. Referral rates were similar in the most urban and rural areas, but they were significantly higher in areas of intermediate urbanization. Correlations of problem scores with those obtained 10 years earlier in a regional survey and with surveys in other countries showed considerable consistency in the rank order of prevalence rates among specific problems. Apparently owing to its more differentiated response scales, the ACQ was susceptible to respondent characteristics that reduced its discriminative power below that of the Child Behavior Checklist. Comparisons of procedures for discriminating between the normal and the clinical range supported the value of a borderline category for children who are neither clearly normal nor clearly deviant. Interview data from the survey sample yielded significantly higher ACQ problem scores for children who had fewer related adults in their homes, those who had more unrelated adults in their homes, those whose biological parents were unmarried, separated, or divorced, those whose families received public assistance, and those whose household or family members had received mental health services. Children who scored higher on Externalizing than Internalizing problems tended to have unmarried, separated, or divorced parents and to come from families receiving public assistance. However, among children whose household or family members had received mental health services, there were greater proportions of both Externalizing and Internalizing patterns than among other children.

A behavioral approach to achieving initial cocaine abstinence.

Abstract: Objective: The aim ofthis study was to assess the efficacy ofa behavioral treatment program f or achieving initial cocaine abstinence in individuals enrolled in outpatient treatment for cocaine dependence. Method: Thirteen consecutively admitted outpatients were offered behavioral treatment consisting of contingency management procedures and the community reinforcement approach. Fifteen consecutively admitted outpatients were offered treatment with 12-step counseling. All 13 of the patients who were offered the behavioral treatment accepted it; 12 ofthe patients offered 12-step counseling accepted it. Results: Eleven ofthe 13 patients in the behavioral treatment were retained for 12 weeks of treatment, compared with five of the I 2 patients given 12-step counseling. Ten of the patients given behavioral therapy achieved 4 weeks of continuous cocaine abstinence, compared with only three of those given 1 2-step counseling. Six of the patients in the behavioral treatment group achieved 8 weeks, and three achieved 12 weeks; none ofthe patients in the 12-step counseling program achieved 8 weeks. Conclusions: The behavioral treatment described in this paper offers promise as an effective intervention for achieving initial cocaine abstinence. A randomized trial is underway to assess the generality of these findings. (AmJ Psychiatry1991; 148:1218-1224)

Symptoms of Tobacco Withdrawal: A Replication and Extension

Abstract: • Smokers (n = 315) who wished to quit were randomly assigned in a double-blind manner to groups using either nicotine or placebo gum. Self-reported and observed symptoms of tobacco withdrawal were collected before cessation and at follow-ups of 1 to 2 weeks, 1 month, and 6 months. Self-reported and/or observed anger, anxiety, craving, difficulty concentrating, hunger, impatience, and restlessness were the most prominent symptoms of tobacco withdrawal. These symptoms had returned to precessation levels by 1 month except increased weight, hunger, and craving continued for 6 months in many smokers. Nicotine gum decreased most symptoms, including craving and hunger but not weight. Abstinent smokers with more intense withdrawal were not more likely to relapse. Abstinent smokers who gained more weight were less likely to relapse.

Hemorrhagic events during therapy with recombinant tissue-type plasminogen activator, heparin, and aspirin for acute myocardial infarction. Results of the Thrombolysis in Myocardial Infarction (TIMI), Phase II Trial.

Abstract: Objectives To assess the effects of invasive procedures, hemostatic and clinical variables, the timing of beta-blocker therapy, and the doses of recombinant plasminogen activator (rt-PA) on hemorrhagic events. Design A multicenter, randomized, controlled trial. Setting Hospitals participating in the Thrombolysis in Myocardial Infarction, Phase II trial (TIMI II). Interventions Patients received rt-PA, heparin, and aspirin. The total dose of rt-PA was 150 mg for the first 520 patients and 100 mg for the remaining 2819 patients. Patients were randomly assigned to an invasive strategy (coronary arteriography with percutaneous angioplasty [if feasible] done routinely 18 to 48 hours after the start of thrombolytic therapy) or to a conservative strategy (coronary arteriography done for recurrent spontaneous or exercise-induced ischemia). Eligible patients were also randomly assigned to either immediate intravenous or deferred beta-blocker therapy. Measurements Patients were monitored for hemorrhagic events during hospitalization. Main results In patients on the 100-mg rt-PA regimen, major and minor hemorrhagic events were more common among those assigned to the invasive than among those assigned to the conservative strategy (18.5% versus 12.8%, P less than 0.001). Major or minor hemorrhagic events were associated with the extent of fibrinogen breakdown, peak rt-PA levels, thrombocytopenia, prolongation of the activated partial thromboplastin time (APTT) to more than 90 seconds, weight of 70 kg or less, female gender, and physical signs of cardiac decompensation. Immediate intravenous beta-blocker therapy had no important effect on hemorrhagic events when compared with delayed beta-blocker therapy. Intracranial hemorrhages were more frequent among patients treated with the 150-mg rt-PA dose than with the 100-mg rt-PA dose (2.1% versus 0.5%, P less than 0.001). The extent of the plasmin-mediated hemostatic defect was also greater in patients receiving the 150-mg dose. Conclusions Increased morbidity due to hemorrhagic complications is associated with an invasive management strategy in patients with acute myocardial infarction. Our findings show the complex interaction of several factors in the occurrence of hemorrhagic events during thrombolytic therapy.

Prognostic value of thallium-201 myocardial perfusion imaging. A diagnostic tool comes of age.

Abstract: D uring the past 10 years, the use of thallium201 myocardial perfusion imaging has undergone considerable expansion and evaluation. Originally conceived as a noninvasive diagnostic tool useful in determining the presence or absence of anatomical coronary artery disease,1-4 201T1 imaging has now been shown to have important prognostic value in a wide spectrum of patients with coronary artery disease.5-49 This prognostic value derives from the ability of 201T1 imaging to identify the presence and extent of jeopardized viable myocardium. After a brief background discussion, data are reviewed that concern the prognostic value of 201T1 imaging in three primary populations-1) patients presenting with known or suspected coronary artery disease, 2) post-myocardial infarction patients, and 3) patients undergoing noncardiac surgery. Data comparing the prognostic value of 201T1 predictors to other patient variables, including clinical, electrocardiographic, and angiographic variables, are discussed. Finally, the physiological basis of these observations are examined.

Diversity of cytokine synthesis and function of mouse CD4+ T cells.

Abstract: The immune response is capable of invoking a variety of difTerent effector mechanisms, each of which is particularly effective against a certain set of pathogens. The regulation of the type of effector mechanisms chosen during an immune response is of critical importance to the host, and thus it is not surprising that this aspect of the immune system is subject to precise and complex regulation. Over the past few years, it has become clear that subsets of T cells secreting distinct patterns of cytokines have a major role in the regulation of the effector functions induced against a particular infectious agent. Two major patterns of cytokine synthesis were initially recognized, and these two patterns appear to correlate with the induction of delayed-type hypersensitivity (DTH) and help for antibody synthesis, thus providing a possible explanation for the separate and often reciprocal regulation of these two responses. Recent information suggests that additional cytokine secretion phenotypes exist, and that there is extensive regulation of the differentiation and effector function of the various cell types.

A meta-analysis of the factors affecting exercise-induced changes in body mass, fat mass and fat-free mass in males and females.

Abstract: A meta-analysis was performed to assess the effects of type, duration and frequency of exercise training on changes in body mass (BM), fat mass (FM), fat-free mass (FFM) and percent body fat (percent fat) both for adult males and females. Weight loss following aerobic type exercise training, though modest, was greater for males. Stepwise regression suggests that, both for males and females, energy expended during exercise and initial body fat levels (or body mass) account for most of the variance associated with changes in BM, FM and percent fat associated with aerobic-type exercise training. In females, weeks of training and duration of exercise per session were also significant predictors. These findings confirm earlier research in males concerning exercise training effects on body mass and body composition and extend them both to females and to a broader range of exercise types. Of particular interest in this regard is the finding that weight training exercise which is similar to aerobic exercise in facilitating body fat loss, can also preserve or increase fat-free mass.

Perceived control and coping with stress: A developmental perspective.

Abstract: This article discusses developmental changes in perceptions of control, the relationship between perceived control and strategies used by children to cope with stress, and the interaction between perceived control and coping in their association with psychological adjustment and disorder. Developmental research on children’s perceptions of control has identifed both changes and consistencies in contingency, competence, and control beliefs during childhood and early adolescence. Developmental changes in coping have also been documented, with problem-focused skills emerging during childhood, and more rapid development of emotion-focused coping skills during later childhood and early adolescence. Studies have shown that perceptions of control are related to the ways that children and adolescents cope with stress. The implications of this research for interventions aimed at enhancing children’s problem-solving and coping skills are discussed. Josh, an 11-year-old boy, and Amy, an 11-year-old girl, both share the common experience of being teased by other children. They find such experiences stressful, but they differ considerably in their beliefs about the controllability of these problems and in their actions to try to deal with them. Although

Calcium-activated chloride current in rabbit ventricular myocytes.

Abstract: We have used the whole-cell patch-clamp technique to examine the ionic basis for a transient outward current in rabbit ventricular myocytes. High concentrations of intracellular calcium buffer prevented the current, isoproterenol increased it, and cadmium, nisoldipine, ryanodine, or caffeine blocked it. These data are consistent with a current that is calcium activated, by the calcium transient that causes contraction. The current was not blocked by external 4-aminopyridine or tetraethylammonium, and it was still present if external potassium was omitted and internal potassium was replaced by cesium. The current was absent when intracellular and extracellular chloride concentrations were drastically reduced, even when intracellular and extracellular potassium concentrations were normal. The current was blocked by the anion transport blockers 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) and responded to extracellular chloride changes as expected for a chloride current. We used SITS and DIDS to define the voltage dependence of the transient outward current. The current first appeared at voltages positive to the threshold of the calcium current and declined as voltage approached the calcium reversal potential. Tail-current experiments suggested that the current rectified strongly in the outward direction. We propose that the 4-aminopyridine-resistant transient outward current of rabbit ventricular myocytes is a calcium-activated chloride current.

Chromium cycling in soils and water : links, gaps, and methods

Abstract: The major links in the cycling of chromium in soils and in natural waters are between chromium(III) and chromium (VI) Between the larger links are lesser links involving processes of mobilization and oxidation of CrIII and reduction of CrVI The gaps are mainly in our understanding of the factors that control these processes If soluble CrIII is added to an "average" soil, a portion of it will become immediately oxidized by manganese oxides to CrVI The rest of the CrIII may remain reduced for long periods of time, even in the presence of electron-accepting manganese oxides However, this less available CrIII can be mobilized by low molecular weight organic complexers and then oxidized where redox conditions are optimal Usually part of any CrVI added to a soil or sediment will be reduced instantly, especially under acid conditions On the other hand, high concentrations of polluting CrVI may quickly exhaust the readily available reducing power of the matrix material and excess CrVI, the thermodynamically stable form in air, may persist for years in soils or lagoons without reduction Cleanup of chromium pollution must involve the surrounding of both CrIII and CrVI with excesses of slowly available reducing substances and sealing them permanently from inputs of atmospheric oxygen Monitoring the effectiveness of the measures is mandatory, but fortunately the chemical testing for CrVI in soil and water is simple and problem free compared with most colorimetric determinations

Chronic lateral ankle instability.

Abstract: Chronic lateral ankle instability may be present in as many as 10% to 30% of people suffering from acute lateral ankle ligament injuries. Ankle instability has been referred to as either functional instability or mechanical instability. Management options consist of either nonoperative or operative treatment, with the majority of the literature emphasizing operative management for chronic instability. Long-term studies assessing the different types of available operative repairs have now been published. This review article discusses chronic lateral ankle ligament instability from a functional, anatomical point of view. The indications for treatment, nonoperative and operative treatment, as well as the biomechanical information available regarding these methods of treatment are considered. The major emphasis of this review is discussion and analysis of the many different surgical treatment options. Following this review, we presently recommend anatomical repair to the bone of both the anterior talofibular ligament and the calcaneofibular ligament, together with imbrication of the ligaments. In patients with hypermobility, long-standing instability, or arthritis, reconstruction using the Chrisman-Snook technique is recommended.

Exosome formation during maturation of mammalian and avian reticulocytes: evidence that exosome release is a major route for externalization of obsolete membrane proteins.

Abstract: We have assessed whether exosome formation is a significant route for loss of plasma membrane functions during sheep reticulocyte maturation in vitro. Although the recovery of transferrin binding activity in exosomes is at best approximately 25-30% of the lost activity, recoveries of over 50% of the lost receptor can be obtained if 125I-labelled transferrin receptor is measured using an that receptor instability may contribute to the less than quantitative recovery of the transferrin receptor. Significantly higher (75-80%) levels of the nucleoside transporter can be recovered in exosomes during red cell maturation using 3H-nitrobenzylthioinosine binding to measure the nucleoside transporter. These data suggest that exosome formation is a major route for removal of plasma membrane proteins during reticulocyte maturation and plasma membrane remodelling. We have also shown that both in vivo and in vitro, embryonic chicken reticulocytes form exosomes which contain the transferrin receptor. Thus, exosome formation is not restricted to mammalian red cells, but also occurs in red cells, which retain organelles, such as nuclei and mitochondria, into the mature red cell stage.

Successful treatment of experimental allergic encephalomyelitis with transforming growth factor-beta 1.

Abstract: Transforming growth factor-beta 1 (TGF-beta 1) is a multifunctional cytokine with immunosuppressive effects on T cells in vitro. Experimental allergic encephalomyelitis is an archetypal T cell-mediated autoimmune demyelinating disease of the central nervous system that often serves as a model for multiple sclerosis. In vivo administration of TGF-beta 1 into SJL mice was successful in reducing the incidence of clinical disease and the histologic severity of inflammation and demyelination in the brain and spinal cord. Immunohistochemical studies performed on control animals showed that TGF-beta-1, -2, and -3 were present in inflammatory perivascular lesions in the brain. The use of a naturally occurring cytokine with immunoregulatory functions in the treatment of an autoimmune disease is novel. However, potential long term complications of such therapy must be addressed before its use in human autoimmune disease such as multiple sclerosis.

Anterior cruciate ligament reconstruction using quadriceps patellar tendon graft Part I. Long-term followup

Abstract: Eighty-three patients with ACL reconstructions using the quadriceps patellar tendon graft were evaluated in a 10 year (mean, 55 years) follow-up study A five-part analysis, consisting of physical examination, questionnaire, Genucom analysis, operative note review, and radiographs, was performed Seventy-six percent were categorized as satisfactory Ninety-two percent were content with their results, while only 4% were unsatisfied Ninety-three percent of the patients had no significant pain and 95% had no giving way postreconstruction Ninety-two percent had no more than a mild functional deficit Eighty-seven percent and 90% of the patients had no significant Lachman or pivot shift by examination, respectively Our results showed no increase in failure over time (1 to 10 years), although those operated on during the initial 5 years showed more radiographic degenerative changes Plotting our results in classification systems of other authors yielded success rates as good as or better than those using our own criteria An objective means by which to quantify laxity did not reliably correlate with the quantifying of laxity made by physical examination Only the lack of a formal rehabilitation program greater than 4 months postoperatively and repaired tears of the medial or lateral collateral ligaments proved to be significant risk factors for poor recovery

Biomechanics of thoracolumbar spinal fixation. A review.

Abstract: Extensive development of spinal instrumentation has occurred recently, benefitted by improved biomechanical knowledge. Reviewed here are various devices and the major biomechanical issues relevant to them. The devices are categorized by site of attachment. The major emphasis is on the most recently developed category: devices attached by transpedicular screws. Aspects of this last category reviewed here include screw design, screw placement, longitudinal linking devices (rods, plates), and transverse connectors (cross-linking). Emphasis is placed not only on current knowledge, but also on unresolved issues.

Effect of thyroid hormone on the expression of mRNA encoding sarcoplasmic reticulum proteins.

Abstract: The purpose of this study was to determine the expression of genes encoding various sarcoplasmic reticulum components that are functionally coupled with calcium release, uptake, and storage function during cardiac hypertrophy induced by thyroid hormone. Hyperthyroidism was induced in two groups of rabbits by the injection of 200 micrograms/kg L-thyroxine (T4) daily for 4 days (T4-4-day group) and 8 days (T4-8-day group). Hypothyroidism was induced in another group of rabbits by adding 0.8 mg/ml propylthiouracil to the drinking water for 4 weeks. The relative expression level of mRNA encoding different sarcoplasmic reticulum proteins was determined by RNA slot blot and Northern blot analysis. In hyperthyroid hearts, the steady-state level of cardiac ryanodine receptor mRNA and sarcoplasmic reticulum cardiac/slow-twitch Ca(2+)-ATPase mRNA were both increased to 147% (T4-4-day group) and 186% (T4-8-day group) of control, respectively, but decreased to 71% and 75%, respectively, in hypothyroid ventricles. The mRNA level for phospholamban was decreased in both hyperthyroidism (T4-8-day group, 72%) and hypothyroidism (77%) in these hearts. On the other hand, calsequestrin mRNA levels did not change in hyperthyroid and hypothyroid ventricles. In accord with the changes in Ca(2+)-ATPase mRNA levels, the Ca(2+)-ATPase protein was increased to 199% (T4-8-day group) in hyperthyroid ventricles and decreased to 86% of control in hypothyroid ventricles. The expression levels of ryanodine receptor, Ca(2+)-ATPase, phospholamban, and calsequestrin mRNAs were similarly altered in skeletal muscle tissues from hyperthyroid and hypothyroid rabbits. These results indicate that the mRNA levels of sarcoplasmic reticulum proteins responsible for calcium release and calcium uptake are coordinately regulated in response to changes in thyroid hormone level in both heart and skeletal muscle. These changes in mRNA level should lead to changes in protein levels and thus to altered calcium release and uptake in the chronic stages of hyperthyroidism and hypothyroidism.

Evidence for invasion of a human oral cell line by Actinobacillus actinomycetemcomitans.

Abstract: Actinobacillus actinomycetemcomitans, an oral bacterial species associated with periodontal disease, was found to invade human cell lines. Invasion was demonstrated by recovery of viable organisms from gentamicin-treated KB cell monolayers and by light and electron microscopy. Internalization occurred through a cytochalasin D-sensitive process. Invasion efficiencies of some A. actinomycetemcomitans strains were comparable to those of invasive members of the family Enterobacteriaceae. Differences in invasiveness were correlated with bacterial colonial morphology. Smooth variants invaded more proficiently than rough variants. A. actinomycetemcomitans can undergo a smooth-to-rough colonial morphology shift which results in the loss of invasiveness. Coordinated regulation of genes involved in the rough-to-smooth phenotypic transitions may play a role in the episodic nature of periodontal disease.

Mutational analysis of CDC42Sc, a Saccharomyces cerevisiae gene that encodes a putative GTP-binding protein involved in the control of cell polarity.

Abstract: The Saccharomyces cerevisiae CDC42 gene product, a member of the ras superfamily of low-molecular-weight GTP-binding proteins, is involved in the control of cell polarity. We have analyzed the effects of three CDC42 mutations (Gly to Val-12, Gln to Leu-61, and Asp to Ala-118) in the putative GTP-binding and hydrolysis domains and one mutation (Cys to Ser-188) in the putative isoprenylation site. The first three mutations resulted in either a dominant-lethal or dose-dependent dominant-lethal phenotype when present on plasmids in haploid cdc42-1ts or wild-type strains. Both wild-type and cdc42-1ts cells carrying plasmids (pGAL) with either the CDC42Val-12 or CDC42Leu-61 alleles under the control of a GAL promoter were arrested with a novel phenotype of large cells with elongated or multiple buds. Cells carrying pGAL-CDC42Ala-118 were arrested as large, round, unbudded cells reminiscent of cdc42-1ts arrested cells. The different phenotype of the CDC42Ala-118 mutant versus the CDC42Val-12 and CDC42Leu-61 mutants was unexpected since the phenotypes of all three analogous ras mutants were similar to each other. This suggests that aspects of the biochemical properties of the Cdc42 protein differ from those of the Ras protein. The cdc42Ser-188 mutant gene was incapable of complementing the cdc42-1ts mutation and was recessive to both wild-type and cdc42-1ts. In double-mutant alleles, the cdc42Ser-188 mutation was capable of suppressing the dominant lethality associated with the three putative GTP-binding and hydrolysis mutations, suggesting that isoprenylation is necessary for the activity of the wild-type and mutant proteins.

The life and times of PSI.

Abstract: This paper describes the essential features of the personalized system of instruction (PSI). Results from outcome research examining the effectiveness of PSI-based courses relative to traditional methods provide unequivocal support for the superiority of PSI. Parametric studies, or component analyses, show that the mastery requirement, immediate performance feedback, and review units are the key features underlying high quality student performances in PSI courses. The use of student proctors as peer-tutors, optional lectures, and selfpacing do not, in and of themselves, appear to be vital to student success in PSI courses. Despite its superiority, PSI has not supplanted traditional methods as the dominant pedagogical system in higher education. Difficulties inherent in overcoming the inertia of the lecture within our established instructional system, the implications of PSI for that system, and the Zeitgeist that permeates educational reform are the major obstacles to widespread adoption of PSI.

The Relation between Serum Albumin Levels and Risk of Coronary Heart Disease in the Multiple Risk Factor Intervention Trial

Abstract: The relation between serum albumin levels and subsequent incidence of myocardial infarction and coronary heart disease deaths was evaluated using stored serum from the Multiple Risk Factor Intervention Trial (MRFIT). There were 91 coronary heart disease deaths, 113 myocardial infarction patients, and 405 controls matched to cases within 5 years of age, treatment group, and clinic site. There was a highly significant inverse relation between serum albumin level and risk of coronary heart disease. Individuals with a baseline level of serum albumin greater than or equal to 4.7 g/dl had an odds ratio of 0.45 as compared with individuals with a baseline level of serum albumin less than 4.4 g/dl. The relation persisted after adjusting for other cardiovascular risk factors (blood pressure, smoking, and serum cholesterol). The association was stronger for coronary heart disease deaths than for surviving myocardial infarction patients, and for cigarette smokers as compared with cigarette nonsmokers. The deaths studied occurred in the time period at least 6 years after the sera had been obtained and up to 10.5 years of follow-up, and the myocardial infarctions studied occurred within the first 6.5 years of follow-up. There was no consistent relation between time and death due to coronary heart disease or myocardial infarction and albumin levels. Albumin levels are related to the acute phase reaction. Lower albumin levels may be a marker of persistent injury to arteries and progression of atherosclerosis and thrombosis. The consistent relation between albumin and coronary heart disease risk requires further evaluation.

Identifying Patients at Risk of Becoming Disabled Because of Low-Back Pain: The Vermont Rehabilitation Engineering Center Predictive Model

Abstract: A predictive risk model of low-back pain (LBP) disability was developed by a panel of six experts in the fields of chronic pain and disability. It comprised 28 factors organized into eight categories: job, psychosocial, injury, diagnostic, demographic, medical history, health behaviors, and anthropometric characteristics and was administered as a 15-minute written questionnaire. The model was tested prospectively on 250 patients (age range, 18-65 years) attending two secondary-care low-back clinics. Disability, as predicted by the model, was compared with 1) actual disability assessed 3 and 6 months later; 2) predictions of disability made by the attending physicians; and 3) predictions obtained from an empirically derived model. These results showed that 1) the expert-generated risk model had a predictive accuracy of 89% and did better in predicting disability than the physicians across all samples and 2) the empirically weighted model did best of all (91% predictive accuracy), suggesting that the expert model used appropriate factors but that the weights assigned to these factors by the panel of experts could be improved.

Energetics of isometric force development in control and volume-overload human myocardium. Comparison with animal species.

Abstract: Alteration in crossbridge behavior and myocardial performance have been associated with myosin isoenzyme composition in animal models of myocardial hypertrophy or atrophy. In the hypertrophied human heart, myocardial performance is altered without significant changes in myosin isoenzymes. To better understand this discrepancy, isometric heat and force measurements were carried out in 1) control and volume-overload human myocardium, 2) control, pressure-overload, and hyperthyroid rabbit myocardium, and 3) control and hypothyroid rat myocardium. In control human myocardium, peak isometric twitch tension was 44.0 +/- 11.7 mN/mm2, and maximum rate of tension rise was 69.2 +/- 21.0 mN/sec.mm2. In volume-overload human myocardium, peak twitch tension and maximum rate of tension rise were reduced by 55% (p less than 0.05) and 65% (p less than 0.05), respectively. The average force-time integral of the individual crossbridge cycle, calculated by myothermal techniques, was increased by 85% (p less than 0.005) in volume-overload human myocardium. In control and hormonally altered myocardium, both across and within species (control human, control rat, control rabbit, hypothyroid rat, and hyperthyroid rabbit), there was a close relation between the crossbridge force-time integral and the percentage of V3-type myosin isoenzyme in the myocardium. However, hemodynamically altered (volume-overload human and pressure-overload rabbit) myocardium did not follow this relation. Across and within species, there were significant correlations between maximum rate of tension rise and average tension-dependent heat rate (r = 0.97, p less than 0.001) and between maximum rate of tension fall and average tension-independent heat rate (r = 0.82; p less than 0.025). Furthermore, there were close inverse relations between these heat rates and the crossbridge force-time integral. In addition, there was an inverse relation between tension-independent heat and the crossbridge force-time integral. Across and within species total myocardial energy turnover was significantly correlated with the crossbridge force-time integral (relative total heat, r = -0.84, p less than 0.02; relative total-activity related heat, r = -0.88, p less than 0.01). The present findings indicate that 1) factors separate from myosin isoenzymes account for the altered crossbridge cycle in volume-overload human and pressure-overload rabbit myocardium, 2) changes in excitation-contraction coupling processes accompany changes in the crossbridge cycle within and across species, and 3) the force-time integral of the crossbridge cycle is a major determinant of total myocardial energy turnover.