Mosaic BRAF Fusions Are a Recurrent Cause of Congenital Melanocytic Nevi Targetable by MAPK Pathway Inhibition

Among children with multiple congenital melanocytic nevi, 25% have no established genetic cause, of whom many develop a hyperproliferative and severely pruritic phenotype resistant to treatment. Gene fusions have been reported in individual cases of congenital melanocytic nevi. We studied 169 patients with congenital melanocytic nevi in this study, 38 of whom were double wild type for pathogenic NRAS/BRAF variants. Nineteen of these 38 patients had sufficient tissue to undergo RNA sequencing, which revealed mosaic BRAF fusions in 11 of 19 patients and mosaic RAF1 fusions in 1 of 19. Recurrently, fusions involved the loss of the 5´ regulatory domain of BRAF or RAF1 but preserved the kinase domain. We validated all cases and detected the fusions in two separate nevi in 5 of 12 patients, confirming clonality. The absence of the fusion in blood in 8 of 12 patients indicated mosaicism. Primary culture of BRAF-fusion nevus cells from 3 of 12 patients demonstrated highly increased MAPK activation, despite only mildly increased BRAF expression, suggesting additional mechanisms of kinase activation. Trametinib quenched MAPK hyperactivation in vitro, and treatment of two patients caused rapid improvement in bulk tissue, improving bodily movement and reducing inflammation and severe pruritus. These findings offer a genetic diagnosis to an additional group of patients and trametinib as a treatment option for the severe associated phenotypes.

PTPN11 Mosaicism Causes a Spectrum of Pigmentary and Vascular Neurocutaneous Disorders and Predisposes to Melanoma

Phakomatosis pigmentovascularis is a diagnosis that denotes the coexistence of pigmentary and vascular birthmarks of specific types, accompanied by variable multisystem involvement, including CNS disease, asymmetrical growth, and a predisposition to malignancy. Using a tight phenotypic group and high-depth next-generation sequencing of affected tissues, we discover here clonal mosaic variants in gene PTPN11 encoding SHP2 phosphatase as a cause of phakomatosis pigmentovascularis type III or spilorosea. Within an individual, the same variant is found in distinct pigmentary and vascular birthmarks and is undetectable in blood. We go on to show that the same variants can cause either the pigmentary or vascular phenotypes alone, and drive melanoma development within pigmentary lesions. Protein structure modeling highlights that although variants lead to loss of function at the level of the phosphatase domain, resultant conformational changes promote longer ligand binding. In vitro modeling of the missense variants confirms downstream MAPK pathway overactivation and widespread disruption of human endothelial cell angiogenesis. Importantly, patients with PTPN11 mosaicism theoretically risk passing on the variant to their children as the germline RASopathy Noonan syndrome with lentigines. These findings improve our understanding of the pathogenesis and biology of nevus spilus and capillary malformation syndromes, paving the way for better clinical management.

Abstract 2014: Mosaic BRAF fusions are a recurrent cause of multiple congenital melanocytic naevi

Congenital melanocytic naevi (CMN) are moles present at birth, and when multiple or very extensive can involve other organ systems as well as predisposing to melanoma. Some CMN patients develop a highly proliferative multinodular phenotype leading to chronic intense pruritus, and the causes for that specific phenotype progression are poorly understood. Genotypically CMN are mosaic single gene disorders. Thus far only two recurrent variants have been described as clearly causative: NRAS missense variants affecting codon 61 accounting for 68% of cases, and BRAF missense variants affecting codon 600 accounting for 7% of cases. Small numbers of cases of CMN have been reported to carry gene-fusions, and in 2 cases in the world literature (one BRAF-fusion and one RAF1-fusion) these have been shown to be clonal and therefore likely causal. We sought to address the issue of causation of the remaining 25%. From an initial large cohort study, skin biopsies from 19 patients were shown to be double wildtype for NRAS/BRAF and had sufficient tissue for further study after deep whole exome sequencing. These 19 samples then underwent transcriptome-wide paired-end RNA sequencing with bioinformatics analysis (STAR-Fusion v1.6 and Fusion Inspector v2.3) for gene fusion transcripts. 11/19 patients were found to have BRAFgene fusions, of which 7 had the multinodular proliferative phenotype. Fusions were confirmed on Sanger sequencing of the cDNA across the fusion junction, specifically demonstrated in 8 children from more than one separate skin lesion, confirming clonality. In the fusions identified, BRAF was fused to 11 different partner genes (GOLGA4, QKI, STRN3, AGAP3, MKRN2, PHIP, LCA5, EEA1, AKAP9, SEC31A, MIER3). This resulted in loss of the 5’ regulatory domain of BRAF but preservation of the kinase domain, such that expression was driven by the 5’ fusion partner. This structure follows the pattern of somatic BRAF-fusions reported previously in solid tumors including melanoma. Potential dimerization domains in the partner genes were identified in 9 cases. We identify here mosaic BRAF fusions as a recurrent cause of multiple CMN allowing genetic diagnosis in a further 15% of cases and linking this genotype to a highly proliferative pruritic phenotype. In vitro data from melanoma cell lines have suggested that higher expression levels of the fusion protein as well as dimerization domains in the partner gene correlate with resistance and/or paradoxical MAP-kinase activation after treatment with RAF and MEK inhibitors. This may have implications for the use of targeted therapies for attempted reduction of the nodular phenotype, or where melanoma arises in CMN patients caused by mosaic BRAF-fusions.

Citation Format: Sara Barberan Martin, Satyamaanasa Polubothu, Alicia Bruzos, Neil Bulstrode, Gavin Kelly, Veronica Kinsler. Mosaic BRAF fusions are a recurrent cause of multiple congenital melanocytic naevi [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2014.

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.

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.

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.

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.

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%).

MIF is a pituitary-derived cytokine that potentiates lethal endotoxaemia

Cytokines are critical in the often fatal cascade of events that cause septic shock. One regulatory system that is likely to be important in controlling inflammatory responses is the neuroendocrine axis. The pituitary, for example, is ideally situated to integrate central and peripheral stimuli, and initiates the increase in systemic glucocorticoids that accompanies host stress responses. To assess further the contribution of the pituitary to systemic inflammatory processes, we examined the secretory profile of cultured pituitary cells and whole pituitaries in vivo after stimulation with bacterial lipopolysaccharide (LPS). Here we identify macrophage migration inhibitory factor (MIF) as a major secreted protein release by anterior pituitary cells in response to LPS stimulation. Serum analysis of control, hypophysectomized and T-cell-deficient (nude) mice suggests that pituitary-derived MIF contributes to circulating MIF present in the post-acute phase of endotoxaemia. Recombinant murine MIF greatly enhances lethality when co-injected with LPS and anti-MIF antibody confers full protection against lethal endotoxaemia. We conclude that MIF plays a central role in the toxic response to endotoxaemia and possibly septic shock.

The role of cricopharyngeus muscle in pharyngoesophageal disorders

The cricopharyngeus muscle is generally thought to be responsible for the high pressure zone of the pharyngoesophageal (upper esophageal) sphincter. In this review we critically examined the evidence for the role of the cricopharyngeus muscle in the manometric pharyngoesophageal sphincter. The available studies show disparities between the anatomic location of the cricopharyngeus muscle and the manometric high pressure zone of the pharyngoesophageal sphincter. The cricopharyngeus muscle seems to correspond to the distal 1/3 of the sphincteric high pressure zone and the peak high pressure zone appears to be located proximal to the cricopharyngeus muscle. The discrepancy between the upper high pressure zone and the anatomic cricopharyngeus is important in understanding the role of the cricopharyngeus muscle in the pathophysiology and treatment of clinical disorders of the pharyngoesophageal sphincter.

Regulatory properties of brain glutamate decarboxylase (GAD): the apoenzyme of GAD is present principally as the smaller of two molecular forms of GAD in brain

The apoenzyme of glutamate decarboxylase [enzyme without bound cofactor, pyridoxal 5'-phosphate (pyridoxal-P)] serves as a reservoir of inactive glutamate decarboxylase (GAD) that can be activated when additional GABA synthesis is required. We have investigated which of two molecular forms of GAD is present as apoenzyme in synaptosomes and in cortex, caudate nucleus, hippocampus, and cerebellum of rat brain. Endogenous glutamate apodecarboxylase (apoGAD) was labeled by incubating extracts of synaptosomes or punches of each region with 32P-pyridoxal-P, followed by reduction with NaBH4, to link covalently the 32P-pyridoxal-P to GAD. Proteins were separated by SDS-PAGE. Punches from all four brain regions and forebrain synaptosomes contained two forms of GAD with apparent Mrs of 63 and 65 kDa as identified by immunoblotting with four antiGAD sera. Punches and synaptosomes contained a major 32P-pyridoxal-P-labeled band with an apparent Mr of 63 kDa that was stained on immunoblots by the antiGAD serum 1440 and the monoclonal antibody GAD-6, and a minor labeled band at 65 kDa that was stained by the 1440, 6799, and K2 antisera. Synaptosomes contained remarkably few other strongly labeled proteins, but punches contained several other labeled bands. Three additional lines of evidence indicate that the labeled 63-kDa protein is apoGAD: (1) it was purified by immunoaffinity chromatography with the GAD-1 monoclonal antibody; (2) it yielded one major labeled peptide when digested with chymotrypsin, and that peptide appeared identical in peptide-mapping experiments to the labeled active-site peptide isolated from chromatographically prepared rat brain GAD; and (3) its labeling was selectively blocked by 4-deoxypyridoxine 5'-phosphate, a competitive inhibitor of the binding of pyridoxal-P to GAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolonged lumbar spinal drainage after the resection of tumors of the skull base: a cautionary note

A combined transcranial and facial approach was used for an en bloc resection of a malignant angiosarcoma of the ethmoid sinuses. The patient awoke neurologically intact and was monitored in the Intensive Care Unit. A lumbar subarachnoid drain was placed for the continuous removal of the cerebrospinal fluid (CSF). Approximately 36 hours after surgery, she deteriorated neurologically and demonstrated bilateral extensor posturing to painful stimuli. A computed tomographic scan demonstrated obliteration of the basal cisterns indicative of transtentorial herniation and a small amount of extradural air. Eight hours after the lumbar drain was turned off, the patient had recovered completely. We propose that the patient manifested transtentorial herniation caused by a pressure gradient between the supratentorial and lumbar cistern compartments brought on by the continuous removal of CSF from the lumbar subarachnoid space. We suggest that ventricular drainage should be considered for these cases rather than lumbar drainage. This offers the same advantage of removing the CSF and maintaining low-to-normal intracranial pressure without the risk of transtentorial herniation.

Cofactor interactions and the regulation of glutamate decarboxylase activity

More than 50% of glutamate decarboxylase (GAD) in brain is present as apoenzyme. Recent work has opened the possibility that apoGAD can be studied in brain by labeling with radioactive cofactor. Such studies would be aided by a compound that inhibits specific binding. One possibility is 4-deoxy-pyridoxine 5'-phosphate, a close structural analog of the cofactor pyridoxal 5'-phosphate. The effects of deoxypyridoxine-P on the cyclic series of reactions that interconverts apo- and holoGAD was investigated and found to be consistent with simple competitive inhibition of the activation of apoGAD by pyridoxal-P. As expected from the cycle GAD was inactivated when incubated with glutamate and deoxypyridoxine-P even though cofactor was present, but no inactivation was observed with deoxypyridoxine-P in the absence of glutamate. Deoxypyridoxine-P also stabilized apoGAD against heat denaturation. These effects were quantitatively accounted for by a kinetic model of the apo-holoGAD cycle. Deoxypyridoxine-P inhibited the labeling by [32P]pyridoxal-P of GAD isolated from rat brain. Hippocampal extracts were labeled with [32P]pyridoxal-P and analyzed by SDS-polyacrylamide gel electrophoresis. Remarkably few bands were strongly labeled. The major labeled band (at 63 kDa) corresponded to one of the forms of GAD. Other strongly-labeled bands were observed at 65 kDa (corresponding to the higher molecular weight form of GAD) and at 69--72 kDa. Labeling of the 63- and 65-kDa bands was inhibited by deoxypyridoxine-P, but the 69-72 kDa bands were unaffected, suggesting that the latter were non-specifically labeled. The results suggest that the 63-kDa form of GAD makes up the majority of apoGAD in hippocampus.

Spring or Fall Fumigation for Control of Meloidogyne spp. on Tobacco

Tests were conducted in 1987-88 to compare the efficacy of spring or fall fumigant nematicide applications for control ofMeloidogyne arenaria and M. incognita on tobacco. Chloropicrin, 1,3-D, methyl isothiocyanate, and a methyl isothiocyanate-l,3-D mixture were applied as row treatments. Fenamiphos, fenamiphos + fensulfothion, or ethoprop were applied in the spring as nonfumigant nematicide standards. Fumigant nematicides increased yields and reduced galling (P = 0.01) in all four tests. Spring or fall applications of fumigant nematicides were effective in controlling M. arenaria and M. incognita and were superior to the nonfumigant nematicides tested.

Glutamate-dependent active-site labeling of brain glutamate decarboxylase

A major regulatory feature of brain glutamate decarboxylase (GAD) is a cyclic reaction that controls the relative amounts of holoenzyme and apoenzyme [active and inactive GAD with and without bound pyridoxal 5'-phosphate (pyridoxal-P, the cofactor), respectively]. Previous studies have indicated that progression of the enzyme around the cycle should be stimulated strongly by the substrate, glutamate. To test this prediction, the effect of glutamate on the incorporation of pyridoxal-P into rat-brain GAD was studied by incubating GAD with [32P]pyridoxal-P, followed by reduction with NaBH4 to link irreversibly the cofactor to the enzyme. Adding glutamate to the reaction mixture strongly stimulated labeling of GAD, as expected. 4-Deoxypyridoxine 5'-phosphate (deoxypyridoxine-P), a close structural analogue of pyridoxal-P, was a competitive inhibitor of the activation of glutamate apodecarboxylase by pyridoxal-P (Ki = 0.27 microM) and strongly inhibited glutamate-dependent labeling of GAD. Analysis of labeled GAD by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis showed two labeled proteins with apparent molecular masses of 59 and 63 kDa. Both proteins could be purified by immunoaffinity chromatography on a column prepared with a monoclonal antibody to GAD, and both were labeled in a glutamate-dependent, deoxypyridoxine-P-sensitive manner, indicating that both were GAD. Three peaks of GAD activity (termed peaks I, II, and III) were separated by chromatography on phenyl-Sepharose, labeled with [32P]pyridoxal-P, purified by immunoaffinity chromatography, and analyzed by SDS-polyacrylamide gel electrophoresis. Peak I contained only the 59-kDa labeled protein. Peaks II and III contained the both the 59- and 63-kDa proteins, but in differing proportions.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of acidity level in simulated rain on disease progress in four plant pathosystems

Field investigations were performed in 1984-1985 on the effects of acidity level in simulated rain on disease dynamics in four pathosystems: alfalfa leaf spot (ALS), peanut leaf spot (PLS), potato late blight (PLB), and soybean brown spot (SBS). Studies were performed in an ambient rain exclusion apparatus with simulated rain acidity levels of pH 2.8, 3.6, 4.2, 4.8, or 5.6 and four plots per pH level. In 1984 for ALS and PLB, rain was simulated three times a week at 6-8 mm per event. For PLS and SBS in 1984 and for PLB, PLS, and SBS in 1985, rain was simulated twice a week at 13-16 mm per event with a 10 min pause halfway through each event. Disease was assessed three times a week. In 1984, no significant effect of acidity level in simulated rain on disease severity was detected in any pathosystem. Severity of PLB differed among treatments in 1985 with significant quadratic and cubic components for the dose-response relationship. PLS severity decreased with increasing level of acidity in simulated rain in 1985 and the dose-response relationship was linear. No differences in severity of ALS or SBS due to acidity of simulated rain were found. Thus, disease response to acidity of simulated rain is system dependent.

Activation of glutamate apodecarboxylase by succinic semialdehyde and pyridoxamine 5'-phosphate

Glutamate apodecarboxylase was activated by incubation with succinic semialdehyde and pyridoxamine 5'-phosphate. Activation required both compounds and was highly selective for succinic semialdehyde. Of 18 analogs tested, only glyoxylate, pyruvate, oxaloacetate, and 2-oxoglutarate activated the apoenzyme significantly, but much higher concentrations of these compounds than of succinic semialdehyde were required. In the presence of pyridoxamine 5'-phosphate, the concentration of succinic semialdehyde giving half-maximal activation of apoenzyme was 7 microM. In contrast, the Ki for succinic semialdehyde as a competitive inhibitor of glutamate decarboxylation was 1.2 mM, indicating that apoenzyme with bound pyridoxamine 5'-phosphate has a much higher affinity for succinic semialdehyde than does holoenzyme. The concentration of pyridoxamine 5'-phosphate giving half-maximal activation was 17 microM, which is more than an order of magnitude greater than the corresponding value for pyridoxal 5'-phosphate.

Transaminations catalysed by brain glutamate decarboxylase

In addition to normal decarboxylation of glutamate to 4-aminobutyrate, glutamate decarboxylase from pig brain was shown to catalyse decarboxylation-dependent transamination of L-glutamate and direct transamination of 4-aminobutyrate with pyridoxal 5'-phosphate to yield succinic semialdehyde and pyridoxamine 5'-phosphate in a 1:1 stoichiometric ratio. Both reactions result in conversion of holoenzyme into apoenzyme. With glutamate as substrate the rates of transamination differed markedly among the three forms of the enzyme (0.008, 0.012 and 0.029% of the rate of 4-aminobutyrate production by the alpha-, beta- and gamma-forms at pH 7.2) and accounted for the differences among the forms in rates of inactivation by glutamate and 4-aminobutyrate. Rates of transamination were maximal at about pH 8 and varied in parallel with the rate constants for inactivation from pH 6.5 to 8.0. Rates of transamination of glutamate and 4-aminobutyrate were similar, suggesting that the decarboxylation step is not entirely rate-limiting in the normal mechanism. The transamination was reversible, and apoenzyme could be reconstituted to holoenzyme by reverse transamination with succinic semialdehyde and pyridoxamine 5'-phosphate. As a major route of apoenzyme formation, the transamination reaction appears to be physiologically significant and could account for the high proportion of apoenzyme in brain.

Effect of clonidine on growth hormone, prolactin, luteinizing hormone, follicle-stimulating hormone, and thyroid-stimulating hormone in the serum of normal men

Clonidine (0.15 mg iv), a selective noradrenergic receptor agonist, increased serum growth hormone (GH) levels (greater than 6 ng/ml) on 8 out of 12 administrations to 6 normal men. This increase was independent of the hypotensive effects of the drug and unrelated to changes in serum cortisol. Clonidine induced a hyperglycemic effect in all subjects which was greatest 15 min after commencint the injection. No changes in blood sugar or GH occurred after placebo injection. Apomorphine, a selective dopamine receptor agonist, elevated GH in each of these 6 subjects (greater than 10 ng/ml). Clonidine had no effect on serum prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), or thyroid-stimulating hormone (TSH). These data are compatible with a dual dopaminergic and noradrenergic mechanism modulating GH secretion in normal men and with the absence of a noradrenergic mechanism in the regulation of PRL, LH, FSH, or TSH.