HEp-2 cell-adherent Escherichia coli in patients with human immunodeficiency virus-associated diarrhea

Diarrhea occurs commonly in African human immunodeficiency virus (HIV) infections. A case-control (HIV-positive vs. -negative) study of adults with diarrhea was done in Lusaka, Zambia, to determine the prevalence of intestinal infection by HEp-2 cell-adherent Escherichia coli. Adherent E. coli were more common in HIV-positive patients with acute diarrhea than among HIV-negative controls (60% vs. 33%) and were found significantly more often in HIV-positive patients with chronic diarrhea than among HIV-negative controls with chronic diarrhea (79% vs. 17%, P < .002). Adherent strains were found significantly more often among HIV-positive patients (69%) than in 22 asymptomatic subjects (36%, P < .02). The HEp-2 cell adherence of the E. coli strains did not show a common pattern. Adherent bacteria were also observed in colonic biopsies from 32% of Zambians with chronic diarrhea who underwent endoscopy. Adherent E. coli may be an important cause of HIV-associated diarrhea in Zambia.     

Uptake of tyramine by rat hepatocytes

Observations on the uptake of tyramine by hepatocytes indicate that the amine is taken up by simple diffusion and a transporter mediated system, with a Km of 39 microM and a Vmax of 270 pmol/min/10(5) cells. The carrier-mediated process is pH- and temperature-dependent and requires an activation energy of 12.9 kcal/mol. An overshoot uptake is achieved a few minutes after adding this amine to the cell suspension, suggesting that active transport is involved. This is supported by the finding that partial inhibition of the uptake can be induced by oligomycin, azide, cyanide and dinitrophenol. NO3-, SCN- and SO4(2-), which change the membrane potential significantly, and depress the transporter mediated uptake further, suggesting that the membrane potential is the driving force for the entry of this amine across hepatic membrane. Cysteine is essential for the normal carrier function; whereas, histidine, tryptophan, arginine and lysine do not directly deal with the activity of the carrier. Many substances, but not amino acids, H, M, and N receptor agonists, can inhibit the uptake of tyramine. It is possible that other amines can enter hepatocytes by using this transporter.     

A robust,portable H-TDMA for field use

The complexity of a typical hygroscopicity tandem differential mobility analyser (H-TDMA) can make it an awkward instrument for fieldwork. An improved design is presented here which is both light-weight, portable and permits very precise, reliable hygroscopic growth, deliquescence and efflorescence measurements for aerosols over a continuous relative humidity range from 10% to 95% without reconfiguration.The method achieves this through three significant advances in H-TDMA design: Firstly, the approach efficiently regulates the humidity by rapidly alternating the air flow between a dryer and a saturator, with the time spent in each path controlled by a feedback loop connected to the humidity sensor. Secondly, the temperature of the aerosol humidifier is directly coupled to that of the wet DMA by enveloping the humidifier in the wet DMAs excess air flow. Thirdly, a novel arrangement of two Nafion? tubes in the humidifier allows for high humidities without needing to pre-wet the aerosol flow.     

Rapid identification of high particle number emitting on-road vehicles and its application to a large fleet of diesel buses

Pollutant concentrations measured in the exhaust plume of a vehicle may be related to the pollutant emission factor using the CO2 concentration as a measure of the dilution factor. We have used this method for the rapid identification of high particle number (PN) emitting on-road vehicles. The method was validated for PN using a medium-duty vehicle and successfully applied to measurements of PN emissions from a large fleet of on-road diesel buses. The ratio of PN concentration to CO2 concentration, Z, in the exhaust plume was estimated for individual buses. On the average, a bus emitted about 1.5 x 10(9) particles per mg of CO2 emitted. A histogram of the number of buses as a function of Z showed, for the first time, that the PN emissions from diesel buses followed a gamma distribution, with most of the values within a narrow range and a few buses exhibiting relatively large values. It was estimated that roughly 10% and 50% of the PN emissions came from just 2% and 25% of the buses, respectively. A regression analysis showed that there was a positive correlation between Z and age of buses, with the slope of the best line being significantly different from zero. The mean Z value for the pre-Euro buses was significantly greater than each of the values for the Euro I and II buses.     

Child malnutrition in China--present status and changing trend

Halving the malnutrition of under five of years has been set as one of the goals to be achieved by the year of 2000 by Chinese government. So it is important to know the present status of child malnutrition and its trend of changing, in order to predict the possible outcome of the achievement of the goal. According to the Child Survey carried out by the State Statistic Bureau (SSB) in 26 provinces and autonomous regions and 3 municipalities in 1992, the prevalence of malnutrition of under five was: moderate and severe underweight, stunting and wasting were 17.9%, 34.7% and 4.7% respectively. But there are significant differences among urban and rural children and between different provinces. The highest prevalence rate usually occurred in the second year of life of the children, and this may be the result of inadequate weaning food provided to the children. As compared with the data collected in 1987 by SSB in 9 provinces and autonomous regions, an impressive improvement in underweight has occurred within these 5 years. The average declined prevalence was 20.5%. It is specially true for urban children. To stunting, there was also improvement for urban children but not in the rural, resulting and over all increasing of prevalence by 5.9%. To wasting, the prevalence for urban children was low and remained at the same level while there was some what increase in the rural. So, according to these results, with constant economic development and more attempt made in areas and groups at risk, the goal to decrease malnutrition in half in terms of underweight could be reached by the year of 2000.