Construction and use of a replication-competent human immunodeficiency virus (HIV-1) that expresses the chloramphenicol acetyltransferase enzyme.

The construction and properties of an infectious human immunodeficiency virus (HIV) that expresses the bacterial gene chloramphenicol acetyltransferase are described. This virus can be used in vitro to screen for drugs that inhibit HIV infection. The marked virus may also be used to trace the routes of infection from the site of inoculation in animal experiments.     

Myocardial ischaemic/reperfusion injury in the anaesthetized rabbit: comparative effects of halothane and isoflurane

The effects of halothane and isoflurane anaesthesia on myocardial injury in rabbits subjected to coronary artery ligation and subsequent reperfusion were analyzed. Although halothane and isoflurane (at inspired concentrations of 1.0 and 1.5 per cent, respectively) exerted comparable effects on cardiovascular status during ischaemic and reperfusion phases, greater preservation of subcellular integrity (as assessed by mitochondrial and sarcoplasmic reticular ATPase activities and myocardial ionic alterations) and a lower incidence of ventricular fibrillation and severe hypotension occurred with halothane. Our results indicate that in studies of experimental myocardial ischaemia anaesthetics may, independently of cardiovascular actions, influence the nature and extent of resulting injury, possibly by virtue of their differing effects on subcellular membrane systems.     

Interaction between FGF and BMP signaling pathways regulates development of metanephric mesenchyme

Nephrogenesis in the mouse kidney begins at embryonic day 11 and ends approximately 10 days postpartum. During this period, new nephrons are continually being generated from a stem-cell population-the nephrogenic mesenchyme-in response to signals emanating from the tips of the branching ureter. Relatively little is known about the mechanism by which the nephrogenic mesenchyme cell population is maintained at the tips of the ureter in the presence of signals promoting tubulogenesis. Previous studies have shown that a loss of Bmp7 function leads to kidney defects that are a likely result of progressive loss of nephrogenic mesenchyme by apoptosis. The studies presented here demonstrate that BMP7 signaling can prevent apoptosis in explants of metanephric mesenchyme. The surviving mesenchyme cell population, however, is not competent to respond to signals promoting tubulogenesis. In conjunction with FGF2, BMP7 promotes growth and maintains competence of the mesenchyme in vitro. In addition, FGF2 and BMP7 signaling, both independently and in combination, inhibit tubulogenesis. Interestingly, FGF2 and BMP7 also promote expansion of the stromal progenitor cell population in whole kidney culture. Because BMP7 is not produced by stromal progenitor cells, these data suggest a novel interaction between the nephrogenic mesenchyme and stromal progenitor cell populations. A model for the regulation of nephrogenesis by FGF and BMP signaling is presented.     

Chondromalacia of the fabella: a case report

A 46-year-old man suffered from chondromalacia of the fabella after minor trauma to the back of the knee. The condition was misdiagnosed initially as fasciitis, tendinitis, a Baker's cyst and a herniated lumbar intervertebral disc. Pathognomonic signs were pain behind the lateral femoral condyle on palpation and compression of the fabella and also on passive extension of the knee. Conservative management was unsuccessful. Excision of the fabella gave quick and lasting relief.     

Prediction of leisure time exercise behavior among a group of lower-limb disabled adults

The aim of this study was to predict leisure time exercise behavior among a group of 62 lower-limb disabled adults. The theory of reasoned action proposed by Fishbein (Fishbein & Ajzen, 1975) provided a framework for the study. Variables measured included the Fishbein model variables, habit, education, disability type, fitness level, and a 7-day follow-up of exercise behavior. Some 35% of the variance in exercise behavior could be explained; intention was the strongest predictor (.31, p less than .05). In comparison, the ability to predict intentions to exercise by using the other variables was quite poor, with only 7% of the variance explained by habit. None of the Fishbein model variables contributed to this prediction. These results indicated the importance of specific factors, such as the strength of the exercise habit and the cause of disability, on exercise behavior.     

Subcellular myocardial abnormalities in experimental diabetes: role of long-chain acylcarnitines

Long-chain acylcarnitines are membrane-active intermediates of fatty acid metabolism whose intracellular accumulation has been implicated in the myocardial injury associated with both streptozotocin-induced diabetes and acute ischemia. In the present study, rats treated with streptozotocin (50 mg/kg i.v.) exhibited increases in myocardial long-chain acylcarnitines comparable to those previously reported to occur in moderate to severe ischemic injury. With the exception of a reduction in the sedimentable (lysosome-associated) fraction of myocardial N-acetyl-beta-glucosaminidase and a decrease in sarcoplasmic reticulum K+, Ca++-stimulated ATPase activity, other characteristic indices of myocardial ischemic damage, notably inhibition of sarcolemmal and mitochondrial ATPase activities as well as alterations in the ionic composition of myocardial tissue, were not apparent in the hearts of the streptozotocin-diabetic animals. On the basis of in vitro studies using palmitylcarnitine, it does not seem that differential sensitivity to long-chain acylcarnitine inactivation can explain the preferential inhibition of the sarcoplasmic reticulum ATPase enzyme observed in vivo. Our data are consistent with the findings of others suggesting that long-chain acylcarnitines are unlikely to be the most important or sole mediators of myocardial ischemic injury. However, a modulatory role of these substances in myocardial ischemic injury or in determining the increased susceptibility of diabetics to the complications of ischemic heart disease cannot be excluded at present.     

Moderators of the intention-behaviour and perceived behavioural control-behaviour relationships for leisure-time physical activity

Background  

Intention is a key determinant of action. However, there is a gap between intention and behavioural performance that remains to be explained. Therefore, the aim of this study was to identify moderators of the intention-behaviour and perceived behavioural control (PBC)- behaviour relationships for leisure-time physical activity.