Biotransformation of organic sulfides. Part 9. Formation of (S) para-substituted phenyl methyl sulfoxides by biotransformation usingHelminthosporium species NRRL 4671

Phenyl methyl sulfides substituted in thepara position with methyl, fluoro, chloro, bromo, cyano, nitro, amino, acyl, methoxy, thiomethyl and methylsulfinyl groups have been converted to (S) sulfoxides by biotransformation usingHelminthosporium species NRRL 4671. The highest yields and enantiomeric excesses were obtained with bromo, cyano, methoxy, thiomethyl and methylsulfinyl substituents and in two cases (para-Br and -CN) the products could be crystallized to give (S) sulfoxide of ≥ 96% ee.     

Low cost multi user multi platform accessible HPLC data acquisition system

Summary A low cost multi user multi platform accessible HPLC data acquisition system has been designed for use in a laboratory environment. This system uses available HPLC measurement systems that lack modern network communication tools and a low cost computer with reliable software. HPLC data are portable to any other computer by means of File Transport Protocol (FTP) communication and can then be used for data analysis. Off line analysis of ethanol data showed a substantial improvement over the old system in terms of data accuracy and skewness. Furthermore, off line data analysis could resolve hidden acetaldehyde peaks which revealed to be oscillatory.     

Comparison of techniques for measuring pulse-wave velocity in the rat

Mitchell, Gary F., Marc A. Pfeffer, Peter V. Finn, andJanice M. Pfeffer. Comparison of techniques for measuringpulse-wave velocity in the rat. J. Appl.Physiol. 82(1): 203-210, 1997.We evaluatedmethods for measuring average and regional pulse-wave velocity alongthe full length of the aorta in 18-mo-old ether-anesthetized malespontaneously hypertensive rats. Catheter-tip manometers were placed inthe ascending and descending thoracic aorta via the right carotid andleft femoral arteries, respectively. As the distal catheter waswithdrawn at 1-cm intervals, the relationship between distal catheterinsertion distance and distance between transducers was determined fromthe intercept of the insertion distance vs. transmission delayregression line. Methods that assessed the foot-to-foot time delaybetween pressures accurately predicted the separation between catheters(measured distance of 14.3 cm; intercept of 14.0 ± 0.5 cm;P = not significant) were highlyreproducible (coefficient of variation of 2.3% for repeated measurements) and showed minimal variability (range 509 ± 30 to 600 ± 29 cm/s) along the full length of the aorta. Methods that madeuse of the pressure-pressure transfer function were spatially (range ofvalues along the aorta 367 ± 17 to 722 ± 39 cm/s) and temporally more variable, especially during vasoconstriction with methoxamine, due to the effects of reflected waves.

     

Modeling the population dynamics of annual plants with seed bank and density dependent effects

A model is proposed for the population dynamics of an annual plant (Sesbania vesicaria) with a seed bank (i.e. in which a proportion of seeds remain dormant for at least one year). A simple linear matrix model is deduced from the life cycle graph. The dominant eigenvalue of the projection matrix is estimated from demographic parameters derived from field studies. The estimated values for population growth rate () indicates that the study population should be experiencing a rapid exponential increase, but this was not the case in our population.The addition of density dependent effects on seedling survivorship and adult fecundity, effects for which field studies provide evidence, considerably improves our model. Depending on the demographic parameters, the model leads to stable equilibrium, oscillations, or chaos. Study of the behaviour of this model in the parameter space shows that the existence of a seed bank allows higher among-year variation of adult fecundity, without leaving the region of demographic stability. Field data obtained over 3 years confirm this prediction.     

Increased Neopterin Levels in Brains of Patients with Human Immunodeficiency Virus Type 1 Infection

Postmortem levels of native neopterin (D-erythro-neopterin) were measured in cerebral cortical samples from 44 human immunodeficiency virus type 1-infected and eight uninfected, nonneurological control patients. Cerebral cortical gray and white matter neopterin levels for the controls ranged from 0.5 to 7.2 pmol/mg of protein in contrast to neopterin levels in brains of the virus-infected patients, which frequently were more than threefold and occasionally more than 30-fold higher than mean control levels. Cortical neopterin levels did not correlate with severity of the acquired immunodeficiency syndrome dementia complex, but subcortical levels correlated with the presence of active human immunodeficiency virus type 1 infection, as reflected by pathological evidence of multinucleated giant cell encephalitis. Evidence of opportunistic cytomegalovirus infections in approximately 25% of the human immunodeficiency virus type 1-infected patients was associated with enhanced levels of neopterin in frontal cortex.     

Lactate dehydrogenase (LDH) activity of the cultured eukaryotic cells as marker of the number of dead cells in the medium [corrected]

One significant problem in monitoring a culture's evolution is to assess change in cell viability. We have demonstrated that LDH release could be a good indicator of cellular damage of many cell lines, especially during shear stress or sonication. Moreover, we have found a significant correlation between the number of dead cells, determined by Trypan Blue staining, and LDH activity measurements in the supernatant of hybridoma strains, whatever the culture conditions. We have also shown that when viability is still near 100% no LDH is released even at high cell concentrations. Therefore, LDH should serve as a potential marker of cell injury and death.     

Effect of clinician information sessions on diagnostic testing for Chagas disease

BackgroundChagas disease is a potentially life-threatening neglected disease of poverty that is endemic in continental Latin America. Caused by Trypanosoma cruzi (T. cruzi), it is one of six parasitic diseases in the United States targeted by the Centers for Disease Control as a public health problem in need of action. An estimated 300,000 people are infected with T. cruzi in the United States (US). Although its morbidity, mortality and economic burden are high, awareness of Chagas disease is lacking among many healthcare providers in the US. The purpose of this analysis is to determine if the number of diagnostic tests performed at a community health center serving an at-risk population for Chagas disease increased after information sessions. A secondary aim was to determine if there was a difference by provider type, i.e., nurse practitioner vs. physician, or by specialty in the number of patients screened.Methodology/Principal findingsWe conducted a retrospective data analysis of the number of Chagas serology tests performed at a community health center before and after information sessions for clinicians. A time series analysis was conducted focusing on the Adult and Family Medicine Departments at East Boston Neighborhood Health Center (EBNHC). Across all departments there were 1,957 T. cruzi tests performed before the sessions vs. 2,623 after the sessions. Interrupted time series analysis across departments indicated that testing volume was stable over time prior to the sessions (pre-period slope = +4.1 per month; p = 0.12), followed by an immediate shift after the session (+51.6; p = 0.03), while testing volume remained stable over time after the session (post-period slope = -6.0 per month; p = 0.11).Conclusion/SignificanceIn this study, Chagas testing increased after information sessions. Clinicians who began testing their patients for Chagas disease after learning of the importance of this intervention added an extra, potentially time-consuming task to their already busy workdays without external incentives or recognition.