Street-level diplomacy and local enforcement for meat safety in northern Tanzania: knowledge, pragmatism and trust.

BACKGROUND: With increasing demand for red meat in Tanzania comes heightened potential for zoonotic infections in animals and humans that disproportionately affect poor communities. A range of frontline government employees work to protect public health, providing services for people engaged in animal-based livelihoods (livestock owners and butchers), and enforcing meat safety and food premises standards. In contrast to literature which emphasises the inadequacy of extension support and food safety policy implementation in low- and middle-income countries, this paper foregrounds the 'street-level diplomacy' deployed by frontline actors operating in challenging contexts. METHODS: This research is based on semi-structured interviews with 61 government employees, including livestock extension officers/meat inspectors and health officers, across 10 randomly-selected rural and urban wards. RESULTS: Frontline actors combined formal and informal strategies including the leveraging of formal policy texts and relationships with other state employees, remaining flexible and recognising that poverty constrained people's ability to comply with health regulations. They emphasised the need to work with livestock keepers and butchers to build their knowledge to self-regulate and to work collaboratively to ensure meat safety. Remaining adaptive and being hesitant to act punitively unless absolutely necessary cultivated trust and positive relations, making those engaged in animal-based livelihoods more open to learning from and cooperating with extension officers and inspectors. This may result in higher levels of meat safety than might be the case if frontline actors stringently enforced regulations. CONCLUSION: The current tendency to view frontline actors' partial enforcement of meat safety regulations as a failure obscures the creative and proactive ways in which they seek to ensure meat safety in a context of limited resources. Their application of 'street-level diplomacy' enables them to be sensitive to local socio-economic realities, to respect local social norms and expectations and to build support for health safety interventions when necessary. More explicitly acknowledging the role of trust and positive state-society relations and the diplomatic skills deployed by frontline actors as a formal part of their inspection duties offers new perspectives and enhanced understandings on the complicated nature of their work and what might be done to support them.

Genomic and clinical characterization of a familial GIST kindred intolerant to imatinib.

Familial gastrointestinal stromal tumors (GIST) are rare. We present a kindred with multiple family members affected with multifocal GIST who underwent whole genome sequencing of the germline and tumor. Affected individuals with GIST harbored a germline variant found within exon 13 of the KIT gene (c.1965T>G; p.Asn655Lys, p.N655K) and a variant in the MSR1 gene (c.877 C > T; p.Arg293*, pR293X). Multifocal GISTs in the proband and her mother were treated with preoperative imatinib, which resulted in severe intolerance. The clinical features of multifocal GIST, cutaneous mastocytosis, allergies, and gut motility disorders seen in the affected individuals may represent manifestations of the multifunctional roles of KIT in interstitial cells of Cajal or mast cells and/or may be suggestive of additional molecular pathways which can contribute to tumorigenesis.

Measuring Glymphatic Flow in Man Using Quantitative Contrast-Enhanced MRI.

On the basis of animal models, glymphatic flow disruption is hypothesized to be a factor in the development of Alzheimer's disease. We report the first quantitative study of glymphatic flow in man, combining intrathecal administration of gadobutrol with serial T1 mapping to produce contrast concentration maps up to 3 days postinjection, demonstrating performing a quantitative study using the techniques described feasibility and providing data on pharmacokinetics.

One Health contributions towards more effective and equitable approaches to health in low- and middle-income countries.

Emerging zoonoses with pandemic potential are a stated priority for the global health security agenda, but endemic zoonoses also have a major societal impact in low-resource settings. Although many endemic zoonoses can be treated, timely diagnosis and appropriate clinical management of human cases is often challenging. Preventive 'One Health' interventions, e.g. interventions in animal populations that generate human health benefits, may provide a useful approach to overcoming some of these challenges. Effective strategies, such as animal vaccination, already exist for the prevention, control and elimination of many endemic zoonoses, including rabies, and several livestock zoonoses (e.g. brucellosis, leptospirosis, Q fever) that are important causes of human febrile illness and livestock productivity losses in low- and middle-income countries. We make the case that, for these diseases, One Health interventions have the potential to be more effective and generate more equitable benefits for human health and livelihoods, particularly in rural areas, than approaches that rely exclusively on treatment of human cases. We hypothesize that applying One Health interventions to tackle these health challenges will help to build trust, community engagement and cross-sectoral collaboration, which will in turn strengthen the capacity of fragile health systems to respond to the threat of emerging zoonoses and other future health challenges. One Health interventions thus have the potential to align the ongoing needs of disadvantaged communities with the concerns of the broader global community, providing a pragmatic and equitable approach to meeting the global goals for sustainable development and supporting the global health security agenda.This article is part of the themed issue 'One Health for a changing world: zoonoses, ecosystems and human well-being'.

Straelensiosis in two cats and ten dogs from Israel.

Straelensiosis is uncommonly described outside Europe. This report describes straelensiosis in two cats and in ten dogs diagnosed with the disease outside Europe. Both cats displayed erythematous macules or nodules on the abdominal skin. One cat was extremely pruritic, while in the other the lesions were incidental findings when the cat was presented for neutering. The mites were noted in skin scrapings in both cats and histopathologically in one cat. All dogs showed a general distribution of papules, and intense pruritus was noted in six dogs. The diagnosis in all dogs was based on histopathology. Treatment of the animals in this study varied, and among the various administrated treatments, amitraz showed promising results.

Relative morbidity of abdominal hysterectomy and myomectomy for management of uterine leiomyomas.

OBJECTIVE: To compare the morbidity of total abdominal hysterectomy and abdominal myomectomy in the surgical management of uterine leiomyomas. METHODS: Hospital records were reviewed for all women who underwent hysterectomy (n = 89) or myomectomy (n = 103) between May 1, 1988, and May 1, 1993, for the preoperative diagnosis of leiomyoma. RESULTS: There were significant differences between the two groups for average age (hysterectomy 39.2 years, myomectomy 34.4 years; mean difference 4.8, 95% confidence interval [CI] of difference 3.7-5.9), uterine size (hysterectomy 15.2, myomectomy 11.5 weeks; mean difference 3.8, 95% CI of difference 2.0-5.4) and use of a GnRH agonist (hysterectomy 23.6%, myomectomy 55.3%; relative risk [RR] 0.4, 95% CI 0.3-0.6). Myomectomy was associated with decreased estimated blood loss (hysterectomy 796 mL, myomectomy 464 mL; mean difference 331, 95% CI 121-542) and febrile morbidity (risk of temperature 38C or 48 or more hours postoperatively: for hysterectomy 49.4%, for myomectomy 32%; RR 1.5, 95% CI 1.1-2.2). Using multivariate linear regression, estimated blood loss was similar between the groups after controlling for uterine size. There was no difference in blood transfusion rates. There were two ureteral, one bladder, one bowel, and one femoral nerve injury in the hysterectomy group, and there were no intraoperative visceral injuries in the myomectomy group. CONCLUSION: Myomectomy compares favorably to hysterectomy in the surgical management of leiomyomas, with a possible decreased risk for visceral injury and infection.

Myomectomy fever: testing the dogma.

OBJECTIVE: To test the hypothesis that elevated temperature is more common after abdominal myomectomy than after hysterectomy. DESIGN: Retrospective cohort study. SETTING: Academic medical center. PATIENT(S): One hundred one women who underwent abdominal myomectomy and 160 women who underwent total abdominal hysterectomy for benign disease from 1988-1993. INTERVENTION(S): Abdominal myomectomy. MAIN OUTCOME MEASURE(S): Temperature of > or = 38.5 degrees C within 48 hours after operation. RESULT(S): Although univariate analysis showed that the incidence of elevated temperature was slightly greater among patients who underwent myomectomy (33% versus 26%, relative risk 1.29, 95% confidence interval 0.88-1.90), multivariate logistic regression analysis showed a 3.29 relative risk of elevated temperature (95% confidence interval 1.56-6.96) with myomectomy after controlling for age, parity, estimated blood loss, and treatment by the general gynecology service. CONCLUSION(S): After controlling for confounders, myomectomy was found to be an independent predictor for fever in the first 48 hours after operation.

Large-scale finite element analysis of the beating heart.

The regional mechanics of the beating heart are directly related to factors such as ventricular pumping performance, coronary blood flow, myocardial energetics and oxygen consumption, vulnerability to ischemia and injury, hypertrophy and remodeling, and arrhythmogenesis. Important characteristics include: the complex three-dimensional geometry and fibrous architecture; the nonlinear, nonhomogeneous, anisotropic material properties of the myocardium; the hierarchical collagen connective tissue matrix; the time- and history-dependent active tension development of the cardiac muscle cells; and the three-dimensional anisotropic patterns of cardiac impulse propagation. To model these features realistically requires large-scale computational analysis with sophisticated numerical methods. As described in the chapter by Dr. Hunter and colleagues, an accurate three-dimensional finite element model has been developed to describe the geometry, fiber architecture, and extracellular matrix structure of the heart. The model is based on extensive anatomical measurements in the left and right ventricles (LV and RV) of the canine heart. In this chapter, we illustrate some new approaches to the special problems of large-scale finite element modeling in biomechanics using examples from the analysis of stress and electrical activation in the heart. Prospects for further progress--particularly in coupled problems such as cardiac electromechanics--are examined in light of new developments in high-performance computing.

Distributed mechanics of the canine right ventricle: effects of varying preload.

Fundamental questions in the mechanics of the right ventricle (RV) include: what are the distributions of diastolic and systolic strains across the RV epicardium and how do these strains change with increasing preload? Arrays (approximately 4 x 4 cm) of 25 to 30 lead markers were sutured to the epicardium of the RV anterior free wall in 6 open-chest, anesthetized dogs. Biplane cinéradiography (16 mm, 120 fps) was used to track marker positions throughout the cardiac cycle as loading conditions were altered by intravenous volume infusion. Continuous two-dimensional nonhomogeneous deformations were estimated across the region by fitting high-order finite element surfaces to the three-dimensional marker coordinates in successive ciné frames. End-systolic strains referred to end-diastole did not change with increasing preload, but did exhibit considerable longitudinal variation, e.g. the principal strain associated with maximal shortening (E1) was more than twice as great nearer the apex (E1 = -0.18 +/- 0.08) than in more basal (E1 = -0.09 +/- 0.05) regions. However, large amounts of lengthening occurred during diastolic inflation. End-diastolic extensional strains referred to an unloaded configuration were moderate at low pressure (E2 = 0.13 +/- 0.08) but increased to large values at high preloads (E2 = 0.28 +/- 0.11). End-diastolic strains also showed considerable longitudinal variation, i.e. near the base lengthening (E2 = 0.31 +/- 0.13) tended to be much greater than near the apex (E2 = 0.15 +/- 0.12). These results indicate that both diastolic sarcomere lengths and systolic sarcomere shortening increase in proportion to diastolic loading leaving end-systolic sarcomere strains unchanged.

Nonhomogeneous analysis of epicardial strain distributions during acute myocardial ischemia in the dog.

To study the nonuniform mechanical function that occurs in normal and ischemic ventricular myocardium, a new method has been developed and validated. An array of 25 lead markers (approximately 4 x 4 cm) was sewn onto the epicardium of the anterior free wall of the left ventricle in an open-chest, anesthetized canine preparation. Biplane cineradiography was used to track marker positions throughout the cardiac cycle before and during episodes of acute ischemia induced by occlusion of the left anterior descending coronary artery. To estimate two-dimensional nonhomogeneous deformations in the region at risk and its border zone with normally perfused tissue, surfaces defined by bicubic Hermite isoparametric finite element interpolation were fitted by least squares to the three-dimensional marker coordinates in successive cine frames. Global smoothing functions prevented ill-conditioning in areas of low marker density. Continuous distributions of systolic finite strains referred to the end-diastolic state were obtained under normal and ischemic conditions without the conventional assumption of homogeneous strain analysis. Substantial regional variations in epicardial strains were observed in both the normal and ischemic heart. The method was validated in regions of small to moderate strain variations by comparing the continuous distributions of strain components with piecewise-constant measurements made using marker triplets and homogeneous strain theory. The influence of marker density was examined by recomputing strains from surfaces fitted to subsets of the original array. Further validation of moderate to large strain variations was obtained by simulating a nonuniform distribution of stretch across a planar sheet and computing strains both analytically and using the current method. The new method allows for more comprehensive measurements of distributed ventricular function, providing a tool with which to quantify better the nonhomogeneous function associated with regional ischemia.

Emergency contraception: prescribing practices of general internists compared with other primary care physicians.

Primary care physicians of all specialties should be familiar with prescribing emergency contraception (EC). We conducted a mail survey of 282 randomly sampled physicians in general internal medicine (31%), family medicine (34%) and obstetrics-gynecology (35%). Experience with prescribing EC significantly differed by specialty (63% of general internists, 76% of family physicians, and 94% of obstetrician-gynecologists, p < 0.0001). Controlling for year of graduation, gender, religion and practice location, family physicians [adjusted odds ratio (OR): 2.5, 95% confidence interval (CI): 1.2-5.2] and obstetrician-gynecologists (adjusted OR: 11.2, 95% CI: 4.0-31.3) were still significantly more likely to have ever prescribed EC than general internists. Efforts to increase awareness and knowledge of EC should be aimed at general internists since they provide primary care for many reproductive age women.

Seasonal flank alopecia in affenpinschers.

Two intact, distantly related, female affenpinschers, belonging to a breeder, were referred in March 1993 for the investigation of bilateral, symmetrical flank alopecia in one bitch and bilateral, symmetrical flank, dorsum and tail alopecia in the other; the alopecia occurred from November to May and January to May, respectively. During that period the bitches were kept in a conservatory without artificial heating or lighting. The owner reported that the mother of one bitch had had bilateral, symmetrical flank alopecia during one winter when kept in the conservatory, but was normal the following winter when kept in the house. Three other females and a male exhibited the same clinical signs when kept in the conservatory during the winter. Seasonal flank alopecia has not previously been reported in affenpinschers.

Qualitative development of a patient-reported outcome symptom measure in diarrhea-predominant irritable bowel syndrome.

OBJECTIVES: Despite a documented clinical need, no patient reported outcome (PRO) symptom measure meeting current regulatory requirements for clinically relevant end points is available for the evaluation of treatment benefit in diarrhea-predominant IBS (IBS-D). METHODS: Patients (N=113) with IBS-D participated in five study phases: (1) eight concept elicitation focus groups (N=34), from which a 17-item IBS-D Daily Symptom Diary and four-item IBS-D Symptom Event Log (Diary and Event Log) were developed; (2) one-on-one cognitive interviews (N=11) to assess the instrument's comprehensiveness, understandability, appropriateness, and readability; (3) four data triangulation focus groups (N=32) to confirm the concepts elicited; (4) two hybrid (concept elicitation and cognitive interview) focus groups (N=16); and (5) two iterative sets of one-on-one cognitive interviews (N=20) to further clarify the symptoms of IBS-D and debrief a revised seven-item Diary and four-item Event Log. RESULTS: Of thirty-six concepts initially identified, 22 were excluded because they were not saturated, not clinically relevant, not critical symptoms of IBS-D, considered upper GI symptoms, or too broad or vaguely defined. The remaining concepts were diarrhea, immediate need (urgency), bloating/pressure, frequency of bowel movements, cramps, abdominal/stomach pain, gas, completely emptied bowels/incomplete evacuation, accidents, bubbling in intestines (bowel sounds), rectal burning, stool consistency, rectal spasm, and pain while wiping. The final instrument included a daily diary with separate items for abdominal and stomach pain and an event log with four items completed after each bowel movement as follows: (1) a record of the bowel movement/event and an assessment of (2) severity of immediacy of need/bowel urgency, (3) incomplete evacuation, and (4) stool consistency (evaluated using the newly developed Astellas Stool Form Scale). Based on rounds of interviews and clinical input, items considered secondary or nonspecific to IBS-D (rectal burning, bubbling in intestines, spasms, and pain while wiping) were excluded. CONCLUSIONS: The IBS-D Symptom Diary and Event Log represent a rigorously developed PRO instrument for the measurement of the IBS-D symptom experience from the perspective of the patient. Its content validity has been supported, and future work should evaluate the instrument's psychometric properties.

Facial cellulitis caused by unrecognized foreign body.

Reported is a case of acute infection thought to be of odontogenic origin. The cause of the infection turned out to be a foreign body which had remained asymptomatic for more than 25 years.

Nonhomogeneous ventricular wall strain: analysis of errors and accuracy.

Nonhomogeneous distributions of strains are simulated and utilized to determine two potential errors in the measurement of cardiac strains. First, the error associated with the use of single-plane imaging of myocardial markers is examined. We found that this error ranges from small to large values depending on the assumed variation in stretch. If variations in stretch are not accompanied by substantial regional changes in ventricular radius, the associated error tends to be quite small. However, if the nonuniform stretch field is a result of substantial variations in local curvature from their reference values, large errors in stretch and strain occur. For canine hearts with circumferential radii of 2 to 4 cm, these errors in stretch may be as great as 30 percent or more. Moreover, gradients in stretch may be over- or underestimated by as much as 100 percent. In the second part of this analysis, the influence of random measurement errors in the coordinate positions of markers on strains computed from them is studied. Arrays of markers covering about 16 cm2 of ventricular epicardium are assumed and nonuniform stretches imposed. The reference and deformed positions of the markers are perturbed with Gaussian noise with a standard deviation of 0.1 mm, and then strains are computed using either homogeneous strain theory or a nonhomogeneous finite element method. For the strain distributions prescribed, it is found that the finite element method reduces the error resulting from noise by about 50 percent over most of the region. Accurate measurements of cardiac strain distributions are needed for correlation with and validation of realistic three-dimensional stress analyses of the heart.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of ventricular pacing on finite deformation in canine left ventricles.

Despite the fact that myofibers would be expected to shorten only along their axes, there is now evidence for substantial deformation away from the local myofiber direction in the left ventricle. To determine if the principal directions of deformation could be altered by a physiological stimulus, we examined local three-dimensional finite deformation in the anterior free wall of the left ventricle during normal atrial activation (AA) and, subsequently, during epicardial ventricular pacing (VP) at the site of deformation measurement in open-chest anesthetized dogs. An analysis of variance by repeated measures revealed the following significant changes (P less than or equal to 0.05) in the overall (average of epicardial and endocardial data) strain variables at end systole. Circumferential strain increased from -0.07 (AA) to 0.14 (VP), radial strain decreased from 0.16 (AA) to 0.01 (VP), shear in the tangent plane of the local epicardium decreased from 0.04 (AA) to -0.02 (VP), shear in the plane of the longitudinal and radial coordinates decreased from 0.03 (AA) to -0.03 (VP). Neither the first (greatest shortening) nor the third (greatest lengthening) principal strain changed significantly, but the direction of the first principal axis of deformation projected on the epicardial tangent plane changed from -51 degrees (AA) to -80 degrees (VP) from circumferential. In addition, substantial tipping of the plane of principal shortening away from the epicardial tangent plane was observed, particularly with ventricular pacing. These data indicate that the principal directions of deformation can be altered substantially by changing the activation sequence. In conjunction with the observed shearing deformations, particularly near the endocardium, they support the concept that locally the heart wall deforms as a unit with significant transmural tethering.

Time-dependent inhibition of insulin release: glucose-arginine interactions in the perfused rat pancreas.

The isolated perfused rat pancreas was stimulated sequentially with arginine or glucose to analyze the time-dependent modulation of insulin release. A 10-min perfusion with arginine (5.0 mmol/l) induced 75% inhibition of the insulin response to repeated arginine stimulation 10 min later. When glucose (8.3 mmol/l) was given as two pulses, inhibition of the second insulin response was less pronounced. The inhibitory effect generated by arginine also suppressed the insulin response to glucose (27.7 mmol/l), and this inhibitory effect persisted for over 80 min. Stimulation for 30 min with glucose (27.7 mmol/l) strongly potentiated the insulin responses to a pair of arginine stimuli given 20 min later. However, despite augmented secretion rates, the insulin response to the second arginine pulse was still inhibited by 75%. When insulin secretion was strongly amplified by two 10 min pulses of the synergistic mixture of arginine (5.0 mmol/l) and glucose (8.3 mmol/l), there was no inhibition of the second insulin response. If glucose (8.3 mmol/l) was present during the first arginine stimulation only, the response to the second arginine pulse was inhibited as in control experiments. However, when glucose was added to the second arginine pulse only, the inhibition generated by the first arginine pulse did not express itself, insulin release remaining similar to control.(ABSTRACT TRUNCATED AT 250 WORDS)

Technique for measuring regional two-dimensional finite strains in canine left ventricle.

We developed a technique to measure regional two-dimensional deformations in the myocardium. Three piezoelectric crystals were implanted in a triangular array in the left ventricular anterior midwall in six anesthetized dogs. Each crystal was used in a dual function, to both transmit and receive ultrasonic signals from the other two crystals. In this manner, the three segment lengths of the crystal triangle throughout the cardiac cycle were simultaneously recorded. The orientation of the crystal triangle with reference to the left ventricular long and minor axes was determined. The orientation and three segment lengths of the crystal triangle were used to calculate the circumferential strain E11, the longitudinal strain E22, the in-plane shear strain E12, and the mutually perpendicular principal strains E1 and E2. Also, the orientation of the first principal direction or the in-plane angle was determined, which was defined as the angle between the first principal direction (E1) and the circumferential direction (0 degree). This information fully describes the regional two-dimensional myocardial deformations. This technique was applied to measure regional myocardial deformations at three different left ventricular end-diastolic pressures (LVEDP) of 2 +/- 1 (mean +/- SD), 8 +/- 1, and 17 +/- 2 mm Hg. The first principal direction at end-systole was oriented away from the circumferential direction at low LVEDP (-43 +/- 21 degrees) but became progressively closer in each animal to the circumferential direction as LVEDP increased to mid (-26 +/- 18 degrees) and high (-14 +/- 13 degrees) levels. The end-systolic ratio E11/E1 was 0.6 +/- 0.2 at low LVEDP, but increased toward unity in each animal to 0.9 +/- 0.1 at mid and high LVEDP. Thus, at low LVEDP, the greatest systolic deformation occurred in a direction different from the circumferential orientation. Therefore, circumferential strain measurements (E11) significantly underestimated the greatest systolic deformation (E1). However, as LVEDP increased, the first principal direction rotated closer toward the circumferential orientation, and circumferential strain measurements adequately estimated the greatest systolic deformation. Nevertheless, the presence of significant amounts of shortening along either the longitudinal (E22) or the second principal direction (E2) in the midwall necessitated the use of the two-dimensional method. The change in end-diastolic configuration as LVEDP increased from 1 +/- 1 to 16 +/- 1 mm Hg was also examined. Unlike the end-systolic data, the end-diastolic first principal direction did not deviate significantly from the circumferential direction at any LVEDP.(ABSTRACT TRUNCATED AT 400 WORDS)

Transmural myocardial deformation in the canine left ventricle. Normal in vivo three-dimensional finite strains.

To examine transmural finite deformation in the wall of the canine left ventricle, closely spaced columns of lead beads were implanted at a single site on the left ventricular free wall. The three-dimensional coordinates of these myocardial markers were obtained with high-speed biplane cineradiography. Any four noncoplanar markers forming small tetrahedral volumes (less than or equal to 0.1 cc) were used to calculate finite normal and shear strains with respect to a cardiac coordinate system at end diastole. Due to the symmetry of the finite strain tensor, the algebraic eigenvalue problem could be solved to compute principal strains and the directions of the principal axes of deformation with respect to the reference coordinates. An examination of the principal strains in a number of tetrahedra in five animals indicates that deformation increases with depth beneath the epicardium. For example, the transmural variation of principal shortening strain averages -0.014 +/- 0.009 per 10% increment in thickness from epicardium to endocardium. Furthermore, shortening and thickening strains at midwall and deeper are too large (0.10 to 0.40) to be described accurately by infinitesimal theory. These strains are often accompanied by substantial in-plane and transverse shears which are not predicted by typical membrane or shell theories, indicating that these theories must be applied with caution when computing indices of regional ventricular performance. The directions of the principal axes of shortening vary substantially less than the fiber direction varies across the wall (20 degrees - 40 degrees compared with 100 degrees - 140 degrees for fiber direction), supporting the concept that there are substantial interactions between neighboring fibers in the left ventricular wall.

Mechanics of active contraction in cardiac muscle: Part II--Cylindrical models of the systolic left ventricle.

Models of contracting ventricular myocardium were used to study the effects of different assumptions concerning active tension development on the distributions of stress and strain in the equatorial region of the intact left ventricle during systole. Three models of cardiac muscle contraction were incorporated in a cylindrical model for passive left ventricular mechanics developed previously [Guccione et al. ASME Journal of Biomechanical Engineering, Vol. 113, pp. 42-55 (1991)]. Systolic sarcomere length and fiber stresses predicted by a general "deactivation" model of cardiac contraction [Guccione and McCulloch, ASME Journal of Biomechanical Engineering, Vol. 115, pp. 72-81 (1993)] were compared with those computed using two less complex models of active fiber stress: In a time-varying "elastance" model, isometric tension development was computed from a function of peak intracellular calcium concentration, time after contraction onset and sarcomere length; a "Hill" model was formulated by scaling this isometric tension using the force-velocity relation derived from the deactivation model. For the same calcium ion concentration, the sarcomeres in the deactivation model shortened approximately 0.1 microns less throughout the wall at end-systole than those in the other models. Thus, muscle fibers in the intact ventricle are subjected to rapid length changes that cause deactivation during the ejection phase of a normal cardiac cycle. The deactivation model predicted rather uniform transmural profiles of fiber stress and cross-fiber stress distributions that were almost identical to those of the radial component. These three components were indistinguishable from the principal stresses. Transmural strain distributions predicted at end-systole by the deactivation model agreed closely with experimental measurements from the anterior free wall of the canine left ventricle.