Evaluation of a personal air sampler for twenty-four hour collection of fine particles and semivolatile organics.

The U.S. EPA has conducted an evaluation of a commercially available lightweight fine particle personal sampler for use in human exposure and biomarker studies involving 24-h collections of particulate matter, particle-bound organics such as polycyclic aromatic hydrocarbons (PAHs), and semivolatile organics (PAHs). Independent laboratory evaluation of the prototype design, intended to produce a 2.5-micron aerodynamic diameter cut-point at a flow between 1.5 and 1.7 lpm (liters per minute), indicated that at a challenge flow rate of 1.5 lpm, the sampler provided an aerodynamic cut-point (dp50) of only 1.7 microns. The variance between expected size selection resulted from the prototype's jet diameter dimension being inadvertently based upon a flow rate of 2.0 lpm rather than an intended 1.5-1.7 lpm. Other aerodynamic factors not presently accounted for may also have played an influence. Extrapolated cut-points for flow rates at 1 and 3 lpm for the prototype were determined to be 2.1 and 1.2 microns, respectively. Total losses attributed to unwanted particle retention within the sampler ranged from 10% for 0.91 micron size particles to essentially zero approaching diameters greater than 2.0 microns. The ambient concentration of particles (< 1.7 microns) needed for acceptable gravimetric filter measurements involving 24-h sample collection was determined to be 10 micrograms/m3. Investigation of the sampler to retain and recover PAHs using XAD-2 resin, often of importance in human exposure biomarker studies, indicated that corrected recoveries between 94% and 108% could be obtained for 16 priority pollutant PAH species. Overall evaluation of the personal monitor indicates that it has research utility due to its modular features and size but reconfiguration should be performed that would permit true PM2.5 size selection. The current configuration collects particles less than 2.5 microns at approximately 95% collection efficiency.

Teplice program--the impact of air pollution on human health.

The aim of the Teplice Program is to investigate and assess the impact of air pollution on the health of the population in the district of Teplice, Czech Republic. Characterization of the air pollutants demonstrated unusually high concentrations during winter inversions of fine particles dominated by acidic sulfates, genotoxic organic compounds, and toxic trace elements. The major source of airborne fine particles is the burning of coal for heating and power. Human exposure and biomarker studies demonstrated large seasonal variations in air pollution within the Teplice District and higher seasonal average pollution levels than the comparative district, Prachatice. Personal exposures to fine particles and organic carcinogens [e.g., polycyclic aromatic hydrocarbons (PAH)] were correlated with excretion of PAH metabolites in urine, several trace metals in blood, and DNA adducts in white blood cells. Respiratory and neurobehavioral studies of school children were conducted using questionnaires and clinical measures. A significantly higher prevalence of adverse respiratory symptoms and decreased lung function were found in the Teplice district than in Prachatice. The neurobehavioral studies indicated significantly higher teacher referrals for clinical assessment in Teplice, but the majority of objective performance measures did not differ. Reproductive studies were conducted in both males and females. A study of the effects of exposure on pregnancy and birth found an excess prevalence of low birth weight and premature births in Teplice; these adverse effects were more common in infants conceived in the winter and whose mothers were smokers. Based on questionnaires and medical examination, the reproductive development of young men was not different between districts and seasons, however, measures of semen quality suggest that exposure to high levels of air pollution are associated with transient decrements in semen quality.

Bleb-related endophthalmitis after trabeculectomy with mitomycin C.

PURPOSE: To determine whether filtering blebs resulting from adjunctive use of mitomycin C (MMC) leads to an increased risk of endophthalmitis. METHODS: The authors retrospectively reviewed the records of 232 consecutive trabeculectomies performed at the W. K. Kellogg Eye Center with adjunctive use of MMC from May 1990 through June 1993. Data obtained from the records included patient age, sex, race, type of glaucoma, site of filtration surgery, concentration and duration of exposure to MMC, presence of early or late bleb leakage, and the occurrence of endophthalmitis. RESULTS: Three patients were lost to follow-up less than 1 month after surgery. A total of 229 eyes of 192 patients (11 women and 82 men) were included in the study. Mean follow-up of patients remaining free of infection was 18.5 +/- 10.8 months (range, 1-44 months). The overall incidence of bleb-related endophthalmitis was 2.6%. Endophthalmitis developed in 8% of patients (4 or 50) in whom an inferior approach was used and in 1.1% (2 or 179) in whom a superior approach was used (P = 0.02, Fisher's exact test). The estimated odds ratio for the development of endophthalmitis after trabeculectomy with adjunctive MMC for inferior versus superior filtration sites was 7.7. CONCLUSION: Short-term follow-up of trabeculectomies performed with adjunctive use of MMC demonstrates an overall incidence of endophthalmitis comparable to filtrationprocedures performed with 5-fluorouracil or without antifibrotic agents. However, inferior trabeculectomy performed with adjunctive MMC carries a significantly increased risk of bleb-related endophthalmitis compared with filters performed superiorly.

Mycobacterium fortuitum keratitis. A comparison of topical ciprofloxacin and amikacin in an animal model.

The effect of topical amikacin or topical ciprofloxacin on Mycobacterium fortuitum keratitis was studied in a rabbit model. Two strains of M fortuitum were used: ATCC-6841 [for which mean inhibitory concentrations (MICs) indicated in vitro sensitivity to both drugs] and a cutaneous isolate from a human infection (for which MICs indicated relative in vitro resistance to amikacin but in vitro sensitivity to ciprofloxacin). Both drugs reduced the number of organisms in eyes infected with either strain (all p values < or = 0.01), but in no cases were organisms eliminated from eyes after 4 days of treatment. Amikacin was more effective in reducing the number of organisms in corneas infected with ATCC-6841 than in corneas infected with the patient isolate (p = 0.004), whereas ciprofloxacin was equally effective for treatment of both strains (p > 0.10). These results suggest that topical amikacin or ciprofloxacin may be useful in the treatment of M fortuitum keratitis. However, neither drug was shown to be more effective for treatment of either strain studied (all p values > 0.3).

Sources of mutagenic activity in urban fine particles.

Samples were collected during the winter of 1984-1985 in the cities of Albuquerque, NM and Raleigh NC as part of a US Environmental Protection Agency study to evaluate methods to determine the emission sources contributing to the mutagenic properties of extractable organic matter (EOM) present in fine particles. Data derived from the analysis of the composition of these fine particles served as input to a multi-linear regression (MLR) model used to calculate the relative contribution of wood burning and motor vehicle sources to mutagenic activity observed in the extractable organic matter. At both sites the mutagenic potency of EOM was found to be greater (3-5 times) for mobile sources when compared to wood smoke extractable organics. Carbon-14 measurements which give a direct determination of the amount of EOM that originated from wood burning were in close agreement with the source apportionment results derived from the MLR model.

Hypertension and neurofibromatosis. Case report.

A 14-year-old girl with neurofibromatosis presented with severe hypertension. She was subsequently found to have a cerebellar glioblastoma multiforme and vascular lesions producing coarctation of the abdominal aorta and 50% and 95% stenosis of the left and right renal arteries respectively. No evidence of pheochromocytoma was found. After removal of the cerebellar tumor, marked amelioration of the hypertension suggested that the tumor had a major role in the pronounced elevation of her blood pressure. Patients who have both neurofibromatosis and hypertension should be carefully evaluated for these several potential lesions.

The right paratracheal stripe in blunt chest trauma.

Supine chest radiographs and thoracic arteriograms were obtained in 102 consecutive patients with blunt chest trauma. The initial chest radiographs were reviewed retrospectively without knowledge of the arteriographic findings, and measurements of the right paratracheal stripe were obtained. All patients with right paratracheal stripes less than 5 mm in width had normal arteriograms. In those patients in whom the right paratracheal stripe measured 5 mm or greater, arteriography revealed major arterial injury in 22.9% of cases. It is concluded that measurement of the right paratracheal stripe on supine 102-cm radiographs provides a reliable and quantitative indicator of mediastinal hemorrhage, allowing early arteriographic evaluation.

Fractures of first and second ribs: predictive value for arterial and bronchial injury.

Fractures of the first and second ribs had a very low association with ruptured bronchus (2%) and ruptured aorta or brachiocephalic vessel (8%) in a series of 50 patients. Radiographic abnormalities indicative of ruptured bronchus include massive pneumothorax, pneumomediastinum, subcutaneous emphysema, and lobar or whole lung collapse which may fall to the dependent part of the thorax on erect views. Abnormalities pointing to a laceration of the aorta or one of the brachiocephalic vessels include widening of the superior mediastinum, shift of the trachea or nasogastric tube to the right, enlargement or indistinctness of the aortic knob, and widening of the right paraspinal line. One or more of these abnormalities indicates the need for thoracic aortography. In the absence of these abnormalities, aortography is not indicated solely by the presence of a first or second rib fracture on the chest radiograph.

Polycystic horseshoe kidney.

Polycystic horseshoe kidney is a rare occurrence. Only 8 cases have been previously reported; we add another case to the literature.