Evaluation of emissions and exposures at workplaces using desktop 3-dimensional printer.

There is a paucity of data on additive manufacturing process emissions and personal exposures in real-world workplaces. Hence, we evaluated atmospheres in four workplaces utilizing desktop "3-dimensional" (3-d) printers [fused filament fabrication (FFF) and sheer] for production, prototyping, or research. Airborne particle diameter and number concentration and total volatile organic compound concentrations were measured using real-time instruments. Airborne particles and volatile organic compounds were collected using time-integrated sampling techniques for off-line analysis. Personal exposures for metals and volatile organic compounds were measured in the breathing zone of operators. All 3-d printers that were monitored released ultrafine and fine particles and organic vapors into workplace air. Particle number-based emission rates (#/min) ranged from 9.4 × 109 to 4.4 × 1011 (n = 9samples) for FFF3-d printers and from 1.9 to 3.8 × 109 (n = 2 samples) for a sheer 3-d printer. The large variability in emission rate values reflected variability from the printers as well as differences in printer design, operating conditions, and feedstock materials among printers. A custom-built ventilated enclosure evaluated at one facility was capable of reducing particle number and total organic chemical concentrations by 99.7% and 53.2%, respectively. Carbonyl compounds were detected in room air; however, none were specifically attributed to the 3-d printing process. Personal exposure to metals (aluminum, iron) and 12 different organic chemicals were all below applicable NIOSH Recommended Exposure Limit values, but results are not reflective of all possible exposure scenarios. More research is needed to understand 3-d printer emissions, exposures, and efficacy of engineering controls in occupational settings.

Insights Into Emissions and Exposures From Use of Industrial-Scale Additive Manufacturing Machines.

BACKGROUND: Emerging reports suggest the potential for adverse health effects from exposure to emissions from some additive manufacturing (AM) processes. There is a paucity of real-world data on emissions from AM machines in industrial workplaces and personal exposures among AM operators. METHODS: Airborne particle and organic chemical emissions and personal exposures were characterized using real-time and time-integrated sampling techniques in four manufacturing facilities using industrial-scale material extrusion and material jetting AM processes. RESULTS: Using a condensation nuclei counter, number-based particle emission rates (ERs) (number/min) from material extrusion AM machines ranged from 4.1 × 1010 (Ultem filament) to 2.2 × 1011 [acrylonitrile butadiene styrene and polycarbonate filaments). For these same machines, total volatile organic compound ERs (µg/min) ranged from 1.9 × 104 (acrylonitrile butadiene styrene and polycarbonate) to 9.4 × 104 (Ultem). For the material jetting machines, the number-based particle ER was higher when the lid was open (2.3 × 1010 number/min) than when the lid was closed (1.5-5.5 × 109 number/min); total volatile organic compound ERs were similar regardless of the lid position. Low levels of acetone, benzene, toluene, and m,p-xylene were common to both AM processes. Carbonyl compounds were detected; however, none were specifically attributed to the AM processes. Personal exposures to metals (aluminum and iron) and eight volatile organic compounds were all below National Institute for Occupational Safety and Health (NIOSH)-recommended exposure levels. CONCLUSION: Industrial-scale AM machines using thermoplastics and resins released particles and organic vapors into workplace air. More research is needed to understand factors influencing real-world industrial-scale AM process emissions and exposures.

Particle and vapor emissions from vat polymerization desktop-scale 3-dimensional printers.

Little is known about emissions and exposure potential from vat polymerization additive manufacturing, a process that uses light-activated polymerization of a resin to build an object. Five vat polymerization printers (three stereolithography (SLA) and two digital light processing (DLP) were evaluated individually in a 12.85 m3 chamber. Aerosols (number, size) and total volatile organic compounds (TVOC) were measured using real-time monitors. Carbonyl vapors and particulate matter were collected for offline analysis using impingers and filters, respectively. During printing, particle emission yields (#/g printed) ranged from 1.3 ± 0.3 to 2.8 ± 2.6 x 108 (SLA printers) and from 3.3 ± 1.5 to 9.2 ± 3.0 x 108 (DLP printers). Yields for number of particles with sizes 5.6 to 560 nm (#/g printed) were 0.8 ± 0.1 to 2.1 ± 0.9 x 1010 and from 1.1 ± 0.3 to 4.0 ± 1.2 x 1010 for SLA and DLP printers, respectively. TVOC yield values (µg/g printed) ranged from 161 ± 47 to 322 ± 229 (SLA printers) and from 1281 ± 313 to 1931 ± 234 (DLP printers). Geometric mean mobility particle sizes were 41.1-45.1 nm for SLA printers and 15.3-28.8 nm for DLP printers. Mean particle and TVOC yields were statistically significantly higher and mean particle sizes were significantly smaller for DLP printers compared with SLA printers (p < 0.05). Energy dispersive X-ray analysis of individual particles qualitatively identified potential occupational carcinogens (chromium, nickel) as well as reactive metals implicated in generation of reactive oxygen species (iron, zinc). Lung deposition modeling indicates that about 15-37% of emitted particles would deposit in the pulmonary region (alveoli). Benzaldehyde (1.0-2.3 ppb) and acetone (0.7-18.0 ppb) were quantified in emissions from four of the printers and 4-oxopentanal (0.07 ppb) was detectable in the emissions from one printer. Vat polymerization printers emitted nanoscale particles that contained potential carcinogens, sensitizers, and reactive metals as well as carbonyl compound vapors. Differences in emissions between SLA and DLP printers indicate that the underlying technology is an important factor when considering exposure reduction strategies such as engineering controls.

Expansion of the concept of the Opistholebetinae Fukui, 1929 (Digenea: Opecoelidae Ozaki, 1925), with Magnaosimum brooksae n. g., n. sp. from Tripodichthys angustifrons (Hollard) (Tetraodontiformes: Triacanthidae) in Moreton Bay, Australia.

The Opecoelidae Ozaki, 1925, the largest trematode family, currently lacks an adequate subfamilial organisation. In particular, recent analyses have shown that the sequenced representatives of the Opistholebetinae Fukui, 1929 are nested among taxa currently recognised in the Plagioporinae Manter, 1947, which itself is polyphyletic. The concept of the Opistholebetinae persists because its 25 or so species are united by a distinctive morphology and a narrow host range; species are known only from tetraodontiform fishes, specifically of the Tetraodontidae and Diodontidae, and possess a muscular post-oral ring, unusual pigmented granules throughout the body and a ventral sucker positioned more posteriorly than is typical for other opecoelids. Here we report on Magnaosimum brooksae n. g., n. sp. from a tetraodontiform, Tripodichthys angustifrons (Hollard) (Triacanthidae), collected in Moreton Bay, Australia. The new species has a longer forebody than hindbody, but lacks a post-oral ring and pigmented granules. It resolves to the plagioporine clade containing the Opistholebetinae, but does not form a monophyletic grouping with those taxa. We propose to expand the concept of the Opistholebetinae to include Magnaosimum, as well as Gaevskajatrema Gibson & Bray, 1982, Macvicaria Gibson & Bray, 1982, Pachycreadium Manter, 1954, Peracreadium Nicoll, 1909, Pinguitrema Siddiqi & Cable, 1960, Propycnadenoides Fishcthal & Kuntz, 1964, Pseudopycnadena Saad-Fares & Maillard, 1986, Pycnadena Linton, 1911 and Pycnadenoides Yamaguti, 1938.

Factors related to meeting physical activity guidelines in active college students: A social cognitive perspective.

OBJECTIVE: To examine the relations of sex, exercise self-efficacy, outcome expectations, and social support with meeting physical activity guidelines (PAGs). PARTICIPANTS: Three hundred ninety-six college students participated in this study in the summer 2013. METHODS: Students completed online questionnaires that assessed physical activity behaviors and psychosocial factors (ie, self-efficacy, outcome expectancies, and social support). Students' physical activity profile was categorized as meeting no PAGs, meeting aerobic PAGs only, meeting muscle-strengthening PAGs only, or meeting both PAGs. RESULTS: A multinomial logistic regression revealed that students' sex and psychosocial factors significantly affected the odds of meeting any and all PAGs. Sex significantly moderated the relationship between outcome expectancy and meeting aerobic PAGs and between outcome expectancy meeting muscle-strengthening PAGs. CONCLUSIONS: Results indicate that interventions designed to increase psychosocial factors may increase the likelihood of students meeting any and all PAGs. Social support may be especially beneficial for increasing muscle-strengthening activity.

First Report of Stubby Root Caused by Trichodorus obtusus on Zoysiagrass and Bermudagrass in South Carolina.

In September 2011, diagnostic samples were taken from 'Tifway' Bermudagrass (Cynodon dactylon × C. transvaalensis) tees and from 'Emerald' Zoysia (Zoysia japonica) roughs of a golf course in Charleston, SC. Additional samples were taken from a sod farm located near Charleston, SC from a field of 'Empire' Zoysia. The soil was sandy loam and the samples were taken at a depth of 10 to 15 cm from symptomatic turf. Symptoms on bermudagrass and zoysiagrass included stubby roots and lightly to severely chlorotic or dead patches of irregular sizes and shapes. Nematodes were extracted by sugar centrifugal-flotation and counted. The predominant nematode species recovered was Trichodorus obtusus Cobb, 1913: syn. T. proximus Allen, 1957, n.syn. (3). Nematode densities (per 100 cm3 of soil) were 30 to 170 (average 94, n = 5) at the sod farm, and 30 to 230 (average 107, n = 7) at the golf course. This nematode has been reported as a pathogen of bermudagrass in Florida, where it is more damaging than Paratrichodorus minor, the other stubby root nematode commonly associated with turfgrass (1). In Florida, 120 T. obtusus individuals per 100 cm3 is considered high risk (2). We have encountered several additional samples from across South Carolina with comparable densities since our first diagnosis. Infested soil (94 individuals per 100 cm3) collected from the sod farm was put into columns and planted with 'Empire' sod and maintained in the greenhouse. After 140 days, the population density increased to an average of 230 individuals per 100 cm3. Plants were prone to wilting and new root growth showed symptoms similar to those observed in the field. Morphologic and morphometric identification of T. obtusus was made by examining male and female specimens in temporary water mounts. Males had ventrally curved spicules with three ventral precloacal papillae, with the posterior papilla just anterior to the head of the retracted spicules, one ventromedian cervical papilla anterior to the excretory pore, and tail with non-thickened terminal cuticle. Females had a deep, barrel-shaped, pore-like vulva, and one or two postadvulvar lateral body pores on each side. Males and females had distinctly offset esophagus. Females (n = 10) were 1,100 to 1,440 (1,250) µm long, body width 40 to 53 (45) µm, onchiostyle 63 to 75 (67) µm, and V 583 to 770 (673) µm. Males (n = 10) were 1,076 to 1,353 (1,222) µm long, body width 33 to 45 (39) µm, onchiostyle 62 to 69 (65) µm, and spicule 55 to 63 (59) µm. From individuals representing the two locations, an 898-bp section of the 18S rDNA region was sequenced using primers 37F (5'-GCCGCGAAAAGCTCATTACAAC-3') and 932R (5'-TATCTGATCGCTGTCGAACC-3') (4). A BLASTn search revealed no similar sequences to those of our two populations (Accessions JX289834 and JX279930). As such, it appears that these are the first sequences of this portion of the 18S rDNA for T. obtusus, although a different, non-overlapping portion of 18S was found in GenBank (AY146460) under the synonym T. proximus. To our knowledge, this is the first report of T. obtusus on zoysiagrass and the first report of the species on bermudagrass in South Carolina. References: (1) W. T. Crow and J. K. Welch. Nematropica 34:31, 2004. (2) W. T. Crow et al. Florida Nematode Management Guide. SP-54. University of Florida, Gainesville, 2003. (3) W. Decraemer. The Family Trichodoridae: Stubby Root and Virus Vector Nematodes. Kluwer Academic Publishers, Dordrecht, The Netherlands. Pp. 27-30, 1995. (4) I. Duarte et al. Nematology 12:171, 2010.

Molecular identification of the turf grass rapid blight pathogen.

Rapid blight is a newly described disease on turf grasses, primarily found on golf courses using suboptimal water for irrigation purposes. On the basis of shared morphological characteristics, it has been proposed that the rapid blight pathogen belongs to a genus of stramenopiles, Labyrinthula, which had been known to cause disease of marine plants only. We have collected 10 isolates from four species of turf grass in five states and sequenced portions of the SSU (18S) rDNA gene from each to provide a definitive taxonomic placement for rapid blight pathogens. We also included sequences from Labyrinthuloides yorkensis, Schizochytrium aggregatum, Aplanochytrium sp., Thraustochytrium striatum, Achlya bisexualis and several nonturf-grass isolates of Labyrinthula. We found that rapid blight isolates indeed are placed firmly within the genus Labyrinthula and that they lack detectable genetic diversity in the 18S rDNA region. We propose that the rapid blight pathogens share a recent common ancestor and might have originated from a single, infected population.

Decrease in GABA synthesis rate in rat cortex following GABA-transaminase inhibition correlates with the decrease in GAD(67) protein.

gamma-Aminobutyric acid (GABA) synthesis in the brain is mediated by two major isoforms of glutamic acid decarboxylase, GAD(65) and GAD(67). The contribution of these isoforms to GABA synthesis flux (V(GAD)) is not known quantitatively. In the present study we compared V(GAD) in cortex of control and vigabatrin-treated rats under alpha-chloralose/70% nitrous oxide anesthesia, with total GAD activity and GAD isoform composition (GAD(65) and GAD(67)) measured by enzymatic assay and quantitative immunoblotting. V(GAD) was determined by re-analysis of 13C NMR data obtained ex vivo and in vivo during infusions of [1-13C]glucose using an extension of a model of glutamate-glutamine cycling that included a discrete GABAergic neuronal compartment with relevant interconnecting fluxes. V(GAD) was significantly lower in vigabatrin-treated rats (0.030-0.05 micromol/min per g, P<0.003) compared to the non-treated control group (0.10-0.15 micromol/min per g). The 67-70% decrease in V(GAD) was associated with a 13% decrease in total GAD activity (P=0.01) and a selective 44+/-15% decrease in GAD(67) protein (from 0.63+/-0.10 to 0.35+/-0.08 microg protein/mg tissue, P<0.05); GAD(65) protein was unchanged. The reduction in GAD(67) protein could account for a maximum of approximately 65% of the decrease in V(GAD) in vigabatrin-treated animals suggesting that inhibition of GAD(65) must have also occurred in these experiments, although product inhibition of GAD(67) by increased GABA could play a role. GAD(67) could account for 56-85% of cortical GABA synthesis flux under basal conditions and the entire flux after vigabatrin treatment.

Variables related to meeting the CDC/ACSM physical activity guidelines.

PURPOSE: The purpose of this study was to investigate the relation between perceived importance of physical activity and demographic variables and current physical activity level with specific reference to the CDC/ACSM guidelines for sufficient physical activity for a health benefit. METHODS: Physical activity levels were assessed by a telephone survey of 2002 households throughout the continental United States and the District of Columbia to determine whether the individuals met the CDC/ACSM physical activity guidelines. RESULTS: Results indicate that 68% of the respondents are physically active below the CDC/ACSM criterion. Chi-square analysis revealed significant relationships between meeting the CDC/ACSM physical activity guidelines and 1) perceived importance of physical inactivity as a health risk (P < 0.0001), and 2) gender (P < 0.0001). Logistic regression analysis revealed that having a greater awareness of the health risks of physical inactivity improved the odds ratio (OR = 1.40, 95% CI = 1.21-1.62) of being sufficiently physically active for a health benefit by 40% (P < 0.0001) and being a male improved the odds ratio (OR = 1.45, 95% CI = 1.17-1.79) of being sufficiently physically active for a health benefit by 45% (P < 0.0006). CONCLUSIONS: Implications for health and physical fitness researchers and practitioners are that they need to improve awareness of life span fitness benefits and develop intervention programs based on individuals' current physical activity levels.

Electrostatic respirator filter media: filter efficiency and most penetrating particle size effects.

New electrostatic filter media has been developed for use in 42 CFR 84 negative pressure particulate respirator filters. This respirator filter media was not available for evaluation prior to the change from 30 CFR 11 to 42 CFR 84. Thus, characterization of this filter media is warranted. In this study, the new 42 CFR 84 electrostatic respirator filters were investigated with respect to filter penetration and most penetrating particle size. Three different models of N95 filters, along with one model each of the N99, R95, and P100 class filters were used in this study. First, three of each filter were loaded with a sodium chloride (NaCl) aerosol, and three of each filter were loaded with a dioctyl phthalate (DOP) aerosol to obtain normal background penetration results for each filter. Then, two new filters of each type were dipped in isopropanol for 15 seconds and allowed to dry. This isopropanol dip should reduce or eliminate any electrostatic charge on the fibers of each filter, as reported in the technical literature. These dipped filters, along with controls of each filter type, were tested on a TSI 8160 filter tester to determine the most penetrating particle size. These same filters were then tested against a NaCl aerosol to get final penetration values. Electret filters rely heavily on their electrostatic charge to provide adequate filter efficiencies, and correlations between penetration and a filter's electrostatic characteristics are found in the technical literature. In all six of the filter models tested, filter penetration values increased considerably and the most penetrating particle size noticeably shifted toward larger particles. These results are important in better understanding how these new filter materials perform under various conditions, and they indicate the need for additional research to define environmental conditions that may affect electrostatic filter efficiency.

Structural features and regulatory properties of the brain glutamate decarboxylases.

It is widely recognized that the two major forms of GAD present in adult vertebrate brains are each composed of two major sequence domains that differ in size and degree of similarity. The amino-terminal domain is smaller and shows little sequence identity between the two forms. This domain is thought to mediate the subcellular targeting of the two GADs. Substantial parts of the amino-terminal domain appear to be exposed and flexible, as shown by proteolysis experiments and the locations of posttranslational modifications. The carboxyl-terminal sequence domain contains the catalytic site and shows substantial sequence similarity between the forms. The interaction of GAD with its cofactor, pyridoxal-5' phosphate (pyridoxal-P), plays a key role in the regulation of GAD activity. Although GAD(65) and GAD(67) interact differently with pyridoxal-P, their cofactor-binding sites contain the same set of nine putative cofactor-binding residues and have the same basic structural fold. Thus the cofactor-binding differences cannot be attributed to fundamental structural differences between the GADs but must result from subtle modifications of the basic cofactor-binding fold. The presence of another conserved motif suggests that the carboxyl-terminal domain is composed of two functional domains: the cofactor-binding domain and a small domain that closes when the substrate binds. Finally, GAD is a dimeric enzyme and conserved features of GADs superfamily of pyridoxal-P proteins indicate the dimer-forming interactions are mediated mainly by the carboxyl-terminal domain.

Nutrient Solution Temperature Affects Pythium Root Rot of Tobacco in Greenhouse Float Systems.

Float nutrient solution, soilless media, and ambient temperatures were monitored in two tobacco greenhouses with different heating regimes. Water temperatures at seeding were 11°C in an unheated greenhouse and 17°C in a heated greenhouse. Water temperature differences between greenhouses continued over the duration of seedling production. Media and air temperatures varied diurnally, but not float solution. In a greenhouse float system where water temperatures were constant at 15, 20, 25, or 30°C, seedling disease caused by Pythium myriotylum was correlated with float-water temperature and could be described by quadratic equations (R2 = 0.99) with the lowest level of root necrosis at 15°C. Pythium spp.-infected and noninfected seedlings grown in controlled-temperature water baths were transplanted to the field and evaluated for disease development. Previous infection with P. myriotylum, regardless of float-temperature regime, failed to alter yield, leaf quality, or root necrosis (P = 0.05) in field-grown tobacco.

Regional distribution and relative amounts of glutamate decarboxylase isoforms in rat and mouse brain.

The levels of the two isoforms of glutamate decarboxylase (GAD) were measured in 12 regions of adult rat brain and three regions of mouse brain by sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunoblotting with an antiserum that recognizes the identical C-terminal sequence in both isoforms from both species. In rat brain the amount of smaller isoform, GAD65, was greater than that of the larger isoform, GAD67, in all twelve regions. GAD65 ranged from 77-89% of total GAD in frontal cortex, hippocampus, hypothalamus, midbrain, olfactory bulb, periaqueductal gray matter, substantia nigra, striatum, thalamus and the ventral tegmental area. The proportion of GAD65 was lower in amygdala and cerebellum but still greater than half of the total. There was a strong correlation between total GAD protein and GAD activity. In the three mouse brain regions analysed (cerebellum, cerebral cortex and hippocampus) the proportion of GAD65 (35,47, and 51% of total GAD) was significantly lower than in the corresponding rat-brain regions. The amount of GAD67 was greater than the amount of GAD65 in mouse cerebellum and was approximately equal to the amount of GAD65 in mouse cerebral cortex and hippocampus.

Pseudoacids. II. 2-Acylbenzoic acid derivatives.

Structures of derivatives of cyclic o-acylbenzoic acids, including the chloride, endo- and exocyclic amides, esters and anhydrides, are examined. 3-Chloro-1(3H)-isobenzofuranone (1), orthorhombic, Pbca, a = 11.616 (5), b = 8.120 (3), c = 15.640 (9) A; 3-methoxy-3-phenyl-1(3H)-isobenzofuranone (3), orthorhombic, P2(1)2(1)2(1), a = 6.923 (2), b = 8.291 (4), c = 21.551 (8) A; 3-hydroxy-3-phenyl-N-propyl-1(3H)-isoindolone (4), orthorhombic, P2(1)2(1)2(1), a = 8.662 (4), b = 9.551 (7), c = 17.649 (14) A; 3-(N-morpholino)-1(3H)-isobenzofuranone (5), triclinic, P1, a = 6.172 (4), b = 11.163 (7), c = 17.33 (2) A, alpha = 105.91 (6), beta = 99.85 (6), gamma = 97.57 (5) degrees; 3-(2'-benzoylbenzoyloxy)-3-phenyl-1(3H)-isobenzofuranone (7), triclinic, P1, a = 9.694 (3), b = 10.505 (4), c = 11.163 (4) A, alpha = 80.58 (3), beta = 80.41 (3), gamma = 76.49 (3) degrees; bis[1(3H)-isobenzofuranone-3-yl]ether (8), monoclinic, I2/a, a = 15.31 (2), b = 6.111 (12), c = 28.30 (5) A, beta = 101.61 (12) degrees. An open oxoacid tertiary amide is also described: N-morpholino 2'-benzoylbenzamide (6): monoclinic, P2(1)/c, a = 6.844 (4), b = 15.696 (8), c = 14.154 (7) A, beta = 99.43 (4). Pseudoacid derivatives form planar isobenzofuran and isoindole rings, and the former aldehyde/ketone carbon-heteroatom endocyclic and exocyclic bond distances show bond length variations which correlate with the relative basicities of the attached groups. Structures of both endocyclic and exocyclic nitrogen pseudoamides are reported as well as examples of the normal-pseudoanhydride and the dipseudoanhydride.

Evaluation of a school-based asthma education program for inner-city children.

BACKGROUND: We have previously reported a high prevalence of current asthma-related symptoms affecting predominantly Hispanic, socioeconomically disadvantaged schoolchildren in Southeast San Diego. OBJECTIVE: We sought to assess the impact of a school-based education program on asthma outcomes. METHODS: In cooperation with the San Diego Unified Schools, we developed and implemented a school-based asthma education program. Based on the National Heart, Lung, and Blood Institute consensus guidelines for asthma, the five-session bilingual, interactive curriculum was conducted in 20-minute segments. Asthma knowledge was tested before and after the education program, and asthma severity was prospectively assessed at monthly intervals. Outcome parameters were compared in educated and control (noneducated) fourth grade students with asthma by using nonparametric techniques. RESULTS: After asthma education, students demonstrated improvement with increases in mean scores for: asthma knowledge quiz from 9.9 (SEM = 0.44, n = 34) to 13.7 (SEM = 0.30); peak flowmeter technique from 3.9 (SEM = 0.33, n = 32) to 6.4 (SEM = 0.29); and inhaler technique from 2.3 (SEM = 0.26, n = 32) to 4.3 (SEM = 0.26). All changes were highly significant (p < or = 0.00001 as determined by Wilcoxon matched-pairs signed-rank test). Mean score comparisons for asthmatic control students given paired examinations after a time interval matched with the educated students, did not reach statistical significance: quiz score of 11.3 (SEM = 0.80, n = 11) versus 10.9 (SEM = 0.68), peak flowmeter technique score of 2.6 (SEM = 0.50, n = 18) versus 3.1 (SEM = 0.37) , and inhaler technique score of 2.5 (SEM = 0.37, n = 18) versus 2.2 (SEM = 0.31). Prospective monthly data were collected on 27 educated and 15 control asthmatic subjects. Severity of asthma was not significantly different between groups at entry to the study. Symptom questionnaires, validated for functional asthma severity, revealed a significant reduction in mean symptom scores at 180 days for the educated (2.87, SEM = 0.447) versus the control (4.36, SEM = 0.573) groups (p = 0.0188 as determined by the Mann-Whitney U test). CONCLUSION: Child-centered asthma education can be successfully conducted in the school setting, resulting in increased asthma knowledge, improved skills for peak flowmeter and inhaler use, and a reduction in the severity of asthma symptoms.

First Report of Pythium myriotylum in a Tobacco Seedling Float System in South Carolina.

Float bay production of seedlings accounts for approximately 62% of tobacco (Nicotiana tabacum L.) transplant production in South Carolina. Float systems utilize styrofoam trays containing soilless media that float in plastic-lined bays filled with nutrient solution. Oomycete fungi with motile zoospores, such as Pythium spp., can devastate plants grown hydroponically (3). This poses a serious concern for growers because no fungicides are labeled for control of Pythium spp. in nutrient solutions for tobacco greenhouse float systems. In May 1996, Pythium myriotylum Drechs. was recovered from diseased seedlings produced in float bays in Walterboro, SC. The pathogen was isolated on PAR selective medium (2). Koch's postulates were fulfilled by inoculating plants in an experimental float bay and then reisolating the pathogen on PAR from symptomatic plants. Diseased plants appeared chlorotic and stunted, with water-soaked lesions on the stem. Root systems were severely necrotic and infected plants could not be used as transplants. Disease development was confined to plants sharing a common nutrient solution in individual bays. Within affected bays nearly 100% of plants were diseased, suggesting pathogen spread through the nutrient solution. At the time of disease onset, the grower was attempting a second crop of transplants. The high late-season temperatures were favorable for P. myriotylum, which has a growth optimum of 37°C. Primary inoculum could potentially arise from contaminated media or water and/or improper sanitation procedures in greenhouse maintenance. Pathogenic isolates of several Pythium spp. were found in commercial potting media in North Carolina in 1995 (1). References: (1) D. K. Cartwright et al. Plant Dis. 79:538, 1995. (2) S. N. Jeffers and S. B. Martin. Plant Dis. 70:1038, 1986. (3) M. E. Stanghellini and S. L. Rasmussen. Plant Dis. 78:1129, 1994.

Exposure and sensitization to environmental allergen of predominantly Hispanic children with asthma in San Diego's inner city.

BACKGROUND: Environmental living conditions co-sorting with economic status may influence the disease morbidity rate of childhood asthma in ethnic minority urban poor populations. OBJECTIVES: This study was carried out to assess exposure and sensitization to environmental allergens in southeast San Diego children with current asthma-related symptoms and to determine the utility of environmental control measures. METHODS: Children, 9 to 12 years old, with current asthma-related symptoms were identified and enrolled at four school sites. Skin prick testing with aeroallergens was performed, and allergen in collected dust (from mattresses, pillows, and bedroom carpets) was quantified by enzyme immunoassay. Environmental control instruction and products were provided. RESULTS: Of 41 subjects who underwent skin testing, 51.2% were reactive to environmental allergens (39% to mite, 22% to cockroach, and 9.8% to cat). Mean allergen levels for sensitized subjects were: Der p 1 (11 subjects), 18,722 ng/gm dust; Der f 1 (8 subjects), 5345 ng/gm dust; Fel d 1 (3 subjects), 214 ng/gm dust; Bla 1 (8 subjects), 7.15 U/gm dust; and Bla 2 (8 subjects) 7.13 U/gm dust. Environmental allergen exposure levels were not significantly different between sensitized and nonsensitized subjects. Environmental control measures for mite exposure were completed in six homes of sensitized subjects. One month after treatment, allergen levels fell 91.2% for Der p 1, 98.9% for Der f 1, and 88.2% for Fel d 1. One year after treatment, mite and cat allergen levels remained low. Environmental control had no consistent impact on cockroach allergen levels. CONCLUSION: Environmental allergen sensitization and exposure may be cofactors contributing to increased disease severity in urban poor populations.

Current prevalence of asthma-related symptoms in San Diego's predominantly Hispanic inner-city children.

Ethnic minorities of low socioeconomic status are disproportionately represented in the trends of increasing asthma prevalence, morbidity, and mortality. We surveyed a cohort of 998 fourth-grade students in an impoverished area of southeast San Diego with a high percentage of Hispanic Mexican-Americans. Of the 654 Hispanic 9-12-year-olds, 14.4% were categorized as probable current asthma (within the past year), based on symptom of wheezing or physician diagnosis of asthma [with respiratory symptom(s) or medication]. An additional 13.5% had respiratory symptoms indicating possible asthma. Differences by ethnic group in the percentage of probable asthma or related symptoms were highly significant (p < 0.0001). Among Hispanics with a category of probable asthma, only 57.4% had a physician diagnosis versus 80.6% of black and 85.7% of white students. The frequency of health insurance coverage differed significantly between ethnic groups (p < 0.0001), with Hispanics among the lowest (37.2%).