Modeling breathing-zone concentrations of airborne contaminants generated during compressed air spray painting

This paper presents a mathematical model to predict breathing-zone concentrations of airborne contaminants generated during compressed air spray painting in cross-flow ventilated booths. The model focuses on characterizing the generation and transport of overspray mist. It extends previous work on conventional spray guns to include exposures generated by HVLP guns. Dimensional analysis and scale model wind-tunnel studies are employed using non-volatile oils, instead of paint, to produce empirical equations for estimating exposure to total mass. Results indicate that a dimensionless breathing zone concentration is a nonlinear function of the ratio of momentum flux of air from the spray gun to the momentum flux of air passing through the projected area of the worker's body. The orientation of the spraying operation within the booth is also very significant. The exposure model requires an estimate of the contaminant generation rate, which is approximated by a simple impactor model. The results represent an initial step in the construction of more realistic models capable of predicting exposure as a mathematical function of the governing parameters.     

Application of evaporative light scattering detection to the characterization of combinatorial and parallel synthesis libraries for pharmaceutical drug discovery

The advent of combinatorial and parallel synthesis methodologies in drug discovery have necessitated the development of analytical techniques which permit high throughput quantitative analysis of mixtures of small organic molecules. High pressure liquid chromatography with evaporative light scattering detection has become the major tool for this task. In this article we briefly review the theory of evaporative light scattering detection and the design of commercial instruments, as well as discuss the operational constraints imposed by the exigency of analyzing en masse the product libraries generated by these new drug discovery methods. The application of evaporative light scattering detection to library analysis is illustrated using examples from our library synthesis program. Complemented by ultraviolet absorbance detection for purity assessment and mass spectrometry for product identification, evaporative light scattering detection is the only technique affording sufficient accuracy and sensitivity for high throughput library analysis.     

The use of chemical restraint in helicopter transport

Introduction: Helicopter transport of the combative patient is a major safety hazard facing air medical teams. Although physical restraints alone are helpful, the addition of chemical restraint (CR) often is necessary to control these patients while in flight.

Methods: A survey was conducted to determine the current practices of using nonparalyzing CR in air medical transport programs nationwide. The survey consisted of 24 questions on the use of CR during transport. Each U.S. program belonging to the Association of Air Medical Services was contacted by telephone, and a flight nurse or paramedic provided answers based on personal experience and statistics compiled by his or her individual program.

Results: Of the 100 programs responding, benzodiazepines were used most commonly to control agitation with 51% using midazolam. Patients with a head injury required CR more frequently than any other condition (73%). Crews flying larger aircraft reported less need for CR. A physician order was required by only 30% of the programs, but delays infrequently endangered the patient (2%). Only 7% of the responding programs had a patient whose condition deteriorated because of CR.

Conclusion: CR is necessary in air medical transport. Most programs use short-acting benzodiazepines. Crews in smaller aircraft use CR more frequently, and head injury is the most common condition requiring such restraint.     

Inflammation-induced changes in peripheral glutamate receptor populations

The ionotropic glutamate receptors N-methyl-d-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate (KA) have been localized on subpopulations of unmyelinated and myelinated sensory axons in normal skin. Behavioral studies indicate that activation of these receptors results in nociceptive behaviors and contributes to inflammatory pain. The goal of the present study was to determine if these glutamate receptors might contribute to the peripheral hypersensitivity observed in inflammation. The major findings were that 48 h following complete Freund's adjuvant (CFA)-induced inflammation, the proportions of unmyelinated axons labeled for NMDA, AMPA or KA receptors were 61%, 43% and 48%, respectively, in cutaneous nerves in the inflamed paw compared to 48%, 22% and 27%, respectively, in the non-inflamed paw. The proportions of myelinated axons labeled for NMDA, AMPA or KA receptors were 61%, 61% and 43%, respectively, compared to 43%, 42% and 28%, respectively, in the non-inflamed hindpaw. These increases were all significant. These data indicate that the number of sensory axons containing ionotropic glutamate receptors increases during inflammation, and this may be a contributing factor to peripheral sensitization in inflammation.     

Rapid repeat pregnancy and experiences of interpersonal violence among low-income adolescents

CONTEXT: Rapid repeat pregnancy (RRP) among adolescents, usually defined as pregnancy onset within 12-24 months of the previous pregnancy outcome, has frequently been the target of public health interventions, due to the exacerbation of negative consequences associated with recurrent adolescent pregnancy (and more specifically with childbearing). OBJECTIVE: To examine what, if any, relationship exists between RRP and the experience of interpersonal violence and abuse among low-income adolescents at one semi-urban health center. DESIGN: Case-control study using retrospective chart review. PARTICIPANTS AND SETTING: 100 women aged 13-21 who received prenatal care at one independent nonprofit health center that serves adolescents and their children from June 1994 through June 1996. MAIN OUTCOME MEASURES: Number and timing of pregnancies, occurrence of physical or sexual abuse; other psychosocial risk factors were evaluated. RESULTS: In this population, the experience of any form of physical or sexual violence during the study interval was associated with RRP within 12 months (p = 0.01, OR = 3.46) and 18 months (p = 0.013, OR = 4.29). Other previously reported predictors of RRP, including family stress, financial stress, and other environmental stressors did not reach statistical significance at either 12 months or 18 months in this sample. Of additional note, young women who experienced any form of abuse during the 12-month study interval were substantially more likely to miscarry than were their nonabused peers, and spontaneous abortion was also very strongly associated with RRP (p < 0.00001; OR = 22.6). CONCLUSIONS: The experience of interpersonal violence is correlated with rapid repeat pregnancy among low-income adolescents. This study strongly suggests a need for both extensive screening for partner and family violence among pregnant and postpartum adolescents, and follow-up safety planning support in combination with family planning interventions.     

Transfer of Bacillus thuringiensis plasmids coding for delta-endotoxin among strains of B. thuringiensis and B. cereus.

The recently discovered high-frequency transfer of plasmids between strains of Bacillus thuringiensis was used to study the genetic relationship between plasmids and production of the insecticidal delta-endotoxin crystal. Three strains of B. thuringiensis transmitted the Cry+ (crystal-producing) phenotype to Cry- (acrystalliferous) B. thuringiensis recipients. Agarose gel electrophoresis showed that one specific plasmid from each donor strain was always present in Cry+ "transcipients." The size of the transmissible crystal-coding plasmid varied with the donor strain, being 75 MDal (megadaltons) in size in HD-2, 50 MDal in HD-73, and 44 MDal in HD-263. Immunological analysis showed the Cry+ transcipients to be hybrid strains, having flagella of the recipient serotype and crystals of the donor serotype. These results demonstrate that the structural genes for the delta-endotoxin are plasmid borne. Crystal-coding plasmids also transferred into two strains of the related species Bacillus cereus and yielded transcipients that produced crystals of the same antigenicity as the donor strain.     

Managing drug shortages: seven years' experience at one health system.

A health system's experience in monitoring drug shortages since 1996 within the organization and since 2001 on a national level is described. Since January 1996, the Drug Information Service (DIS) at the University of Utah Hospitals and Clinics (UUHSC) has systematically prepared written bulletins to affected practitioners when drug shortages occurred. The DIS began providing information on a national level to the American Society of Health-System Pharmacists in January 2001. A total of 224 drug shortages were tracked from January 1996 to June 2002. All shortages at UUHSC were also national shortages, but only about two thirds of national shortages also affected UUHSC. The most common reasons for shortages were manufacturing problems (28%) and product discontinuation (20%). The most frequently represented pharmacologic-therapeutic categories were central nervous system agents (24%) and serums, toxoids, and vaccines (17%). Of the 119 shortages in 2001, 70 (59%) were still ongoing as of the end of June 2002. The most common potential safety problems were that clinicians might be unfamiliar with the alternative agent (54%) and that the alternative's dosage requirement was different (50%). Over half of the shortages were cost neutral, but the assessment did not include substantial potential indirect costs. Detailed information on drug shortages collected by a health system's drug information service since 1996 indicated a trend toward more frequent shortages.