Filtration effectiveness of HVAC systems at near-roadway schools.

UNLABELLED: Concern for the exposure of children attending schools located near busy roadways to toxic, traffic-related air pollutants has raised questions regarding the environmental benefits of advanced heating, ventilation, and air-conditioning (HVAC) filtration systems for near-road pollution. Levels of black carbon and gaseous pollutants were measured at three indoor classroom sites and at seven outdoor monitoring sites at Las Vegas schools. Initial HVAC filtration systems effected a 31-66% reduction in black carbon particle concentrations inside three schools compared with ambient air concentrations. After improved filtration systems were installed, black carbon particle concentrations were reduced by 74-97% inside three classrooms relative to ambient air concentrations. Average black carbon particle concentrations inside the schools with improved filtration systems were lower than typical ambient Las Vegas concentrations by 49-96%. Gaseous pollutants were higher indoors than outdoors. The higher indoor concentrations most likely originated at least partially from indoor sources, which were not targeted as part of this intervention. PRACTICAL IMPLICATIONS: Recent literature has demonstrated adverse health effects in subjects exposed to ambient air near major roadways. Current smart growth planning and infill development often require that buildings such as schools are built near major roadways. Improving the filtration systems of a school's HVAC system was shown to decrease children's exposure to near-roadway diesel particulate matter. However, reducing exposure to the gas-phase air toxics, which primarily originated from indoor sources, may require multiple filter passes on recirculated air.

Gonococcemia in pregnancy.

A case of gonococcemia in pregnancy in which the patient presented with the classic clinical manifestations of gonococcemia--cutaneous lesions, arthritis, and possibly pericarditis--is reported. A review of the literature reveals a dramatic increase in incidence of gonorrhea and the increasing importance of the complications associated with this disease, particularly in pregnancy. Recommendations regarding recognition of gonococcemia, criteria for diagnosis, and treatment are presented.

Enzymatic formation and electrochemical characterization of multiply substituted glutathione conjugates of hydroquinone.

1,4-Benzoquinone can undergo redox cycling in the presence of glutathione to produce multiply substituted products. It has previously been shown that the nephrotoxicity of the hydroquinone-glutathione conjugates increases with increasing substitution. However, based on chromatographically-assisted hydrodynamic voltammetry (CA-HDV), the oxidation potential was shown to apparently increase which, should lead to decreased toxicity. From the chemical formation of multiply substituted hydroquinone-glutathione conjugates from benzoquinone and glutathione, it is clear that the thermodynamic oxidation potential must decrease as substitution increases. This was confirmed by cyclic voltammetric (CV) characterization of the isolated conjugates. The discrepancy between the CV and CA-HDV data apparently results from kinetic factors arising from differences in the treatment of the electrode surface between the two experiments. The multiply substituted hydroquinone-glutathione conjugates were also produced in horseradish peroxidase incubations containing hydroquinone and glutathione. These products were identified chromatographically, spectrophotometrically, and electrochemically. The increasing ease of oxidation and the possible enzymatic formation of multiply substituted hydroquinone-glutathione conjugates indicates that this pathway may occur in vivo and contribute to the toxicity of quinones.

Intravenous alcohol -- a single blind study in the prevention of premature delivery: a preliminary report.

A single blind study for the evaluation of intravenous ethanol in the prevention of premature delivery is reported. Randomly selected patients admitted to Tripler General Hospital with uncomplicated pregnancies between 24 and 36 weeks' gestation having regular, sustained contractions were evaluated. Therapy consisted of intravenous 5% ethanol in 5% dextrose/water according to a weight-time-dose schedule. Control patients were given conventional treatment. Statistical evaluation of data has shown no significant difference between success and failure between the study and control groups to date.

Blood volume in pre-eclampsia: fantasy and reality.

A great deal has been stated recently about the importance of hypovolemia in pre-eclampsia and eclampsia from the point of view of pathogenesis and management. Some authors even believe that the so-called hypovolemia represents an etiologic factor and should be "corrected." In this paper, the hemodynamic factors that maintain the circulation in the normal nonpregnant and pregnant states are discussed. These factors are then used as a background for explaining the pathophysiologic abnormalities of the acute hypertensive disease of pregnancy. It is concluded that the slight decrease in blood volume observed in pre-eclampsia has no hemodynamic relevance; the blood volume is merely "fitting" a contracted vascular bed. The major abnormality resides in the constricted arteriolar system and not in the blood volume.

Circulatory effects of endotoxin on unanesthetized sheep and the response to dopamine.

The cardiovascular effects of endotoxin in the unanesthetized chronically instrumented sheep were investigated. The observations were extended to include the response to intravenous infusions of dopamine to the same sheep at the height of endotoxin action. When the cardiovascular effects of endotoxin in the unanesthetized and anesthetized sheep were compared, there were distinct differences. Unanesthetized sheep tolerated considerably greater dosages of endotoxin. In anesthetized sheep, the compensatory stimulation of the sympathoadrenal system seems to have been blunted and all of the circulatory parameters deteriorate rapidly, ending in death within three hours. In the absence of anesthesia, there was clear evidence of a compensatory sympathoadrenal stimulation, as reflected by the return of most of the circulatory parameters to normal values, and furthermore, the sheep recovered from the effects of endotoxin. The exact mechanism by which anesthesia altered the response of the sheep to endotoxin was not clear. Depression of the baroreceptor and neurohumoral compensatory mechanisms was suggested. The present data indicated that dopamine was a useful agent in correcting the cardiovascular changes brought about by endotoxin.

Acute cardiovascular effects of delta-9-tetrahydrocannabinol in pregnant anesthetized sheep.

The effects of pulmonary artery infusion of delta-9-tetrahydrocannabinol (delta 9-THC), 0.5 mg/kg, have been studied in four pregnant sheep. Cardiac output (CO) decreased from a baseline of 4.49 +/- 0.91 l/min (mean +/- s.e.m.) to 4.19 +/- 0.87 at 3 min, 3.69 +/- 0.76 at 5 min, and 3.35 +/- 0.77 at 15 min post infusion and returned to baseline by 1 h post infusion. Maternal blood pressure (MBP) decreased from 114 +/- 9 to a nadir of 69 +/- 8 mmHg at 15 min post infusion. Uterine artery blood flow (UTABF) increased from 256 +/- 88 to 317 +/- 132 ml/min at 3 min post infusion, but this was not statistically significant. Maternal acidosis, hypercapnia, and hypoxemia also developed during the first 15 min post infusion. Although fetal blood pressure (FBP) decreased throughout the 1st h post infusion, statistically significant changes in FBP or fetal heart rate (FHR) were not observed. Umbilical artery blood flow (UMABF) increased from 188 +/- 58 to 211 +/- 68 1/min at 5 min post infusion and declined thereafter. This change was also statistically significant. As in the ewe the fetus developed acidosis and hypoxemia, but hypercapnia, although present, was not statistically significant. A single animal was studied following i.v. infusion of delta 9-THC (1 mg/kg). More pronounced effects, including a decrease in UTABF and UMABF, were noted. The sheep were maintained under pentobarbital anesthesia for the duration of the study.