Microcirculatory disorders in cerebral ischemia in rats and their correction by using leu-enkephalin

Leu-enkephalin (LE) induced mainly a constriction of pial arterioles, diameter of the venules did not change. The effect of the LE involved preservation of the cerebral blood flow and that in microvessels, constriction of some arterioles and reduced dilatation against the background of decreased arterial pressure, bradycardia, increased lymphatic flow and survival of the animals during first hours of occlusion of common carotid arteries.     

Perforation of terminal ileum and appendix in typhoid enteritis: report of two cases

Two cases of simultaneous typhoid perforation of terminal ileum and appendix are reported from Harare Central Hospital. These findings have not been reported before. Perforations were associated with schistosomiasis and HIV/AIDS. Definitive diagnosis was made only after laparotomy, serology and histopathology. With early diagnosis, effective resuscitation and timely intervention, this life-threatening condition is not necessarily fatal. Septic shock is however, an ominous sign of poor prognosis. In the tropics, bradycardia, leukopaenia and perforation in a febrile patient with right iliac fossa tenderness should arouse suspicion. Perforations may occur in patients with underlying diseases.     

Techno-economic aspects of hydrogen storage in an automobile

A comparative techno-economic evaluation of the methods of hydrogen storage in an automobile as to the overall energy consumption is presented. The effect is demonstrated of the storage vessel mass and the primary energy expenditures on the specific energy consumption of the automobile at its given fuel distance endurance. It is shown that, at present, the most expedient systems for automobiles of all types are metal hydride systems. Some aspects of thermal exchange and mass transfer in metal hydride are discussed, which allows an evaluation of the dynamic performance of storage vessels. Test results of prototype automobiles confirm that the use of metal hydride storage vessels is promising, especially if the engine operates on mixed fuel (gasoline and hydrogen).     

Salt effects on ligand-DNA binding. Minor groove binding antibiotics

Salt dependent electrostatic effects play a central role in intermolecular interactions involving nucleic acids. In this paper, the finite-difference solution to the nonlinear Poisson-Boltzmann (NLPB) equation is used to evaluate the salt dependent contribution to the electrostatic binding free energy of the minor groove binding antibiotics DAPI, Hoechst 33258 and netropsin to DNA using detailed molecular structures of the complexes. For each of these systems, a treatment based on the NLPB equation accurately describes the variation of the experimentally observed binding constant with bulk salt concentration. A solvation formalism is developed in which salt effects are described in terms of three free energy contributions: the electrostatic ion-molecule interaction free energy, delta delta G degrees im; the electrostatic ion-ion interaction free energy, delta delta G degrees ii; and the entropic ion organization free energy, delta delta G degrees org. The electrostatic terms, delta delta G degrees im and delta delta G degrees ii, have both enthalpic and entropic components, while the term delta delta G degrees org is purely a cratic entropy. Each of these terms depends significantly on salt dependent changes in the counterion and coion concentrations around the DNA. In each of the systems studied, univalent ions substantially destabilize charged ligand-DNA complexes at physiological salt concentrations. This effect involves a salt dependent redistribution of counterions near the DNA. The free energy associated with the redistribution of counterions upon binding is dominated by the unfavorable change in the electrostatic ion-molecule interactions, delta delta G degrees im, rather than the change in the cratic entropy of ion organization, delta delta G degrees org. In addition, the observed slope of the salt dependence of the free energy is determined by electrostatic ion-molecule and ion-ion interactions as well as the cratic entropy of ion release. These findings are in contrast to models in which the cratic entropy of counterion release drives binding.     

Reproducibility of the acetylene rebreathe technique for determining cardiac output

Acute and subacute extrapyramidal movement disorders are rarely reported in uremic patients. We report three such cases with basal ganglia lesions. All three had advanced renal failure with high serum creatinine levels. One of the patients had a history of ischemic heart disease and acute pulmonary edema with hypoxemia. Another patient had experienced arterial hypotension during previous hemodialysis. The third had prominent metabolic acidosis. One of the patients developed generalized dyskinesias, whereas the other two developed gait disturbances. Neuroimaging studies in all three cases showed bilateral changes in the basal ganglia. The natural history was self-limiting with gradual improvement. Diminution of the basal ganglia lesions was demonstrated on follow-up imaging in two of the three cases. We conclude that acute or subacute movement disorders with bilateral basal ganglia lesions may occur in uremia. Hypoperfusion with global brain ischemia and selective vulnerability of the basal ganglia to uremic toxins may account for these lesions.     

Decreased amniotic fluid volume at < 32 weeks of gestation is associated with decreased fetal movements

The objective of this study was to assess the relationship between amniotic fluid volume (AFV) and fetal movements at < 32 weeks gestation as assessed by routine biophysical profile (BPP). From a database of 465 consecutive nonhypertensive, nondiabetic patients delivering at < 32 weeks gestation, patients with singleton, nonanomalous fetuses with AFV and fetal movements determined as part of a BPP assessment within 24 hours of delivery were studied. Amniotic fluid volume was scored 0 to 2, according to the following criteria: largest pocket in vertical diameter < 1 cm = 0; < 2 but > 1 cm = 1; > or = 2 cm = 2. Fetal movements (FM) were scored over 30 minutes: 0 if absent, 1 if 1 to 2 movements, 2 if > or = 3 gross (limb/trunk) movements. Variables assessed included fetal presentation, gestational age (GA), premature rupture of membranes (PROM) as a principal indication for delivery, clinical chorioamnionitis (diagnosed by previously published criteria), histologic parameters of infection (in amnion and umbilical cord assessed by a single pathologist blinded to clinical data), and neonatal outcome. Statistical analyses included contingency tables and analysis of variance with p < 0.05 considered significant. Three hundred and fifty-two patients met the inclusion criteria. One hundred and sixty-seven patients (47%) had PROM as a primary indication for delivery. Infrequently, decreased fetal well-being manifested by a BPP < 7 of 10 points was an indication for delivery despite prematurity (n = 7). Of the 352 patients, 80 (23%) had AFV = 0, 60 (17%) had AFV = 1, and 212 (60%) had AFV = 2; and 12 (3%) had FM = 0, 30 (9%) FM = 1, and 310 (88%) FM = 2. There was a significant correlation between decreased AFV and decreased fetal movements (p < 0.0001). Fetal presentation and GA were not significantly different between patients based on score of fetal movements. The incidence of clinical chorioamnionitis was significantly greater in patients with FM = 0 (p < 0.005). We conclude that decreased AFV is associated with decreased fetal movements irrespective of fetal presentation or gestational age. Neonatal outcome (umbilical vasculitis, sepsis, intraventricular hemorrhage) is affected only in unusual cases in which otherwise uncompromised (nonhypoxic, nonacidotic) fetuses have low scores on both these antepartum ultrasonographic parameters.