The Impact of ACEs on BMI: An Investigation of the Genotype-Environment Effects of BMI

Adverse Childhood Experiences are stressful and traumatic events occurring before the age of eighteen shown to cause mental and physical health problems, including increased risk of obesity. Obesity remains an ongoing national challenge with no predicted solution. We examine a subset of the Healthy Nevada Project, focusing on a multi-ethnic cohort of 15,886 sequenced participants with recalled adverse childhood events, to study how ACEs and their genotype-environment interactions affect BMI. Specifically, the Healthy Nevada Project participants sequenced by the Helix Exome+ platform were cross-referenced to their electronic medical records and social health determinants questionnaire to identify: 1) the effect of ACEs on BMI in the absence of genetics; 2) the effect of genotype-environment interactions on BMI; 3) how these gene-environment interactions differ from standard genetic associations of BMI. The study found very strong significant associations between the number of adverse childhood experiences and adult obesity. Additionally, we identified fifty-five common and rare variants that exhibited gene-interaction effects including three variants in the CAMK1D gene and four variants in LHPP; both genes are linked to schizophrenia. Surprisingly, none of the variants identified with interactive effects were in canonical obesity-related genes. Here we show the delicate balance between genes and environment, and how the two strongly influence each other.

Using phenome-wide association studies and the SF-12 quality of life metric to identify profound consequences of adverse childhood experiences on adult mental and physical health in a Northern Nevadan population

In this research, we examine and identify the implications of Adverse Childhood Experiences (ACEs) on a range of health outcomes, with particular focus on a number of mental health disorders. Many previous studies observed that traumatic childhood events are linked to long-term adult diseases using the standard Adverse Childhood Experience Questionnaire. The study cohort was derived from the Healthy Nevada Project, a volunteer-based population health study in which each adult participant is invited to take a retrospective questionnaire that includes the Adverse Childhood Experience Questionnaire, the 12-item Short Form Survey measuring quality of life, and self-reported incidence of nine mental disorders. Using participant's cross-referenced electronic health records, a phenome-wide association analysis of 1,703 phenotypes and the incidence of ACEs examined links between traumatic events in childhood and adult disease. These analyses showed that many mental disorders were significantly associated with ACEs in a dose-response manner. Similarly, a dose response between ACEs and obesity, chronic pain, migraine, and other physical phenotypes was identified. An examination of the prevalence of self-reported mental disorders and incidence of ACEs showed a positive relationship. Furthermore, participants with less adverse childhood events experienced a higher quality of life, both physically and mentally. The whole-phenotype approach confirms that ACEs are linked with many negative adult physical and mental health outcomes. With the nationwide prevalence of ACEs as high as 67%, these findings suggest a need for new public health resources: ACE-specific interventions and early childhood screenings.

Histopathology is required to identify and characterize myopathies in high-throughput phenotype screening of genetically engineered mice

The development of mouse models that replicate the genetic and pathological features of human disease is important in preclinical research because these types of models enable the completion of meaningful pharmacokinetic, safety, and efficacy studies. Numerous relevant mouse models of human disease have been discovered in high-throughput screening programs, but there are important specific phenotypes revealed by histopathology that are not reliably detected by any other physiological or behavioral screening tests. As part of comprehensive phenotypic analyses of over 4000 knockout (KO) mice, histopathology identified 12 lines of KO mice with lesions indicative of an autosomal recessive myopathy. This report includes a brief summary of histological and other findings in these 12 lines. Notably, the inverted screen test detected muscle weakness in only 4 of these 12 lines (Scyl1, Plpp7, Chkb, and Asnsd1), all 4 of which have been previously recognized and published. In contrast, 6 of 8 KO lines showing negative or inconclusive findings on the inverted screen test (Plppr2, Pnpla7, Tenm1, Srpk3, Sidt2, Yif1b, Mrs2, and Pnpla2) had not been previously identified as having myopathies. These findings support the need to include histopathology in phenotype screening protocols in order to identify novel genetic myopathies that are not clinically evident or not detected by the inverted screen test.

Gene-by-environment modulation of lifespan and weight gain in the murine BXD family

How lifespan and body weight vary as a function of diet and genetic differences is not well understood. Here we quantify the impact of differences in diet on lifespan in a genetically diverse family of female mice, split into matched isogenic cohorts fed a low-fat chow diet (CD, n = 663) or a high-fat diet (HFD, n = 685). We further generate key metabolic data in a parallel cohort euthanized at four time points. HFD feeding shortens lifespan by 12%: equivalent to a decade in humans. Initial body weight and early weight gains account for longevity differences of roughly 4-6 days per gram. At 500 days, animals on a HFD typically gain four times as much weight as control, but variation in weight gain does not correlate with lifespan. Classic serum metabolites, often regarded as health biomarkers, are not necessarily strong predictors of longevity. Our data indicate that responses to a HFD are substantially modulated by gene-by-environment interactions, highlighting the importance of genetic variation in making accurate individualized dietary recommendations.

Cutaneous Effects of In Utero and Lactational Exposure of C57BL/6J Mice to 2,3,7,8-Tetrachlorodibenzo-p-dioxin

To determine the cutaneous effects of in utero and lactational exposure to the AHR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), pregnant C57BL/6J mice were exposed by gavage to a vehicle or 5 μg TCDD/kg body weight at embryonic day 12 and epidermal barrier formation and function were studied in their offspring from postnatal day 1 (P1) through adulthood. TCDD-exposed pups were born with acanthosis. This effect was AHR-dependent and subsided by P6 with no evidence of subsequent inflammatory dermatitis. The challenge of adult mice with MC903 showed similar inflammatory responses in control and treated animals, indicating no long-term immunosuppression to this chemical. Chloracne-like sebaceous gland hypoplasia and cyst formation were observed in TCDD-exposed P21 mice, with concomitant microbiome dysbiosis. These effects were reversed by P35. CYP1A1 and CYP1B1 expression in the skin was increased in the exposed mice until P21, then declined. Both CYP proteins co-localized with LRIG1-expressing progenitor cells at the infundibulum. CYP1B1 protein also co-localized with a second stem cell niche in the isthmus. These results indicate that this exposure to TCDD causes a chloracne-like effect without inflammation. Transient activation of the AhR, due to the shorter half-life of TCDD in mice, likely contributes to the reversibility of these effects.

Genome-Wide Identification of Rare and Common Variants Driving Triglyceride Levels in a Nevada Population

Clinical conditions correlated with elevated triglyceride levels are well-known: coronary heart disease, hypertension, and diabetes. Underlying genetic and phenotypic mechanisms are not fully understood, partially due to lack of coordinated genotypic-phenotypic data. Here we use a subset of the Healthy Nevada Project, a population of 9,183 sequenced participants with longitudinal electronic health records to examine consequences of altered triglyceride levels. Specifically, Healthy Nevada Project participants sequenced by the Helix Exome+ platform were cross-referenced to their electronic medical records to identify: (1) rare and common single-variant genome-wide associations; (2) gene-based associations using a Sequence Kernel Association Test; (3) phenome-wide associations with triglyceride levels; and (4) pleiotropic variants linked to triglyceride levels. The study identified 549 significant single-variant associations (p < 8.75 × 10-9), many in chromosome 11's triglyceride hotspot: ZPR1, BUD13, APOC3, APOA5. A well-known protective loss-of-function variant in APOC3 (R19X) was associated with a 51% decrease in triglyceride levels in the cohort. Sixteen gene-based triglyceride associations were identified; six of these genes surprisingly did not include a single variant with significant associations. Results at the variant and gene level were validated with the UK Biobank. The combination of a single-variant genome-wide association, a gene-based association method, and phenome wide-association studies identified rare and common variants, genes, and phenotypes associated with elevated triglyceride levels, some of which may have been overlooked with standard approaches.

Early onset of renal oxidative stress in small for gestational age newborn pigs

OBJECTIVE

Oxidative stress, a common feature in cardiovascular and renal disease is associated with the causes and consequences of fetal growth restriction. Hence, renal redox status is likely an early determinant of morbidity in small-for-gestational-age (SGA) infants. In this study, we examined renal oxidative stress in naturally-farrowed SGA newborn pigs.

METHODS

We studied SGA newborn pigs with 52% less body weight and 59% higher brain/liver weight ratio compared with their appropriate-for-gestational-age (AGA) counterparts.

RESULTS

The kidneys of the SGA newborn pigs weighed 56% less than the AGA group. The glomerular cross-sectional area was also smaller in the SGA group. SGA newborn pigs exhibited increased renal lipid peroxidation, reduced kidney and urine total antioxidant capacity, and increased renal nitrotyrosine immunostaining. Whereas the protein expression level of NADPH oxidase (NOX)2 was unchanged, NOX4 expression was significantly higher in SGA kidneys. The level of serum potassium was lower, but serum sodium and creatinine were similar in SGA compared with AGA newborn pigs. The serum concentrations of C-reactive protein and NGAL, the biomarkers of inflammation and early acute kidney injury were significantly elevated in the SGA group.

CONCLUSION

Early induction of oxidative stress may contribute to the onset of kidney injury in growth-restricted infants.

Genome-wide rare variant analysis for thousands of phenotypes in over 70,000 exomes from two cohorts

Understanding the impact of rare variants is essential to understanding human health. We analyze rare (MAF < 0.1%) variants against 4264 phenotypes in 49,960 exome-sequenced individuals from the UK Biobank and 1934 phenotypes (1821 overlapping with UK Biobank) in 21,866 members of the Healthy Nevada Project (HNP) cohort who underwent Exome + sequencing at Helix. After using our rare-variant-tailored methodology to reduce test statistic inflation, we identify 64 statistically significant gene-based associations in our meta-analysis of the two cohorts and 37 for phenotypes available in only one cohort. Singletons make significant contributions to our results, and the vast majority of the associations could not have been identified with a genotyping chip. Our results are available for interactive browsing in a webapp (https://ukb.research.helix.com). This comprehensive analysis illustrates the biological value of large, deeply phenotyped cohorts of unselected populations coupled with NGS data.

Population-based association analyses of rare genetic variants with complex traits are limited by the availability of data from sufficiently large cohorts. Here, Cirulli et al. report gene-based collapsing analysis of exomes from 49,960 participants of the UK Biobank and 21,866 participants of the Healthy Nevada Project over a total of 4377 traits.

GWAS and PheWAS of red blood cell components in a Northern Nevadan cohort

In this study, we perform a full genome-wide association study (GWAS) to identify statistically significantly associated single nucleotide polymorphisms (SNPs) with three red blood cell (RBC) components and follow it with two independent PheWASs to examine associations between phenotypic data (case-control status of diagnoses or disease), significant SNPs, and RBC component levels. We first identified associations between the three RBC components: mean platelet volume (MPV), mean corpuscular volume (MCV), and platelet counts (PC), and the genotypes of approximately 500,000 SNPs on the Illumina Infimum DNA Human OmniExpress-24 BeadChip using a single cohort of 4,673 Northern Nevadans. Twenty-one SNPs in five major genomic regions were found to be statistically significantly associated with MPV, two regions with MCV, and one region with PC, with p<5x10^-8. Twenty-nine SNPs and nine chromosomal regions were identified in 30 previous GWASs, with effect sizes of similar magnitude and direction as found in our cohort. The two strongest associations were SNP rs1354034 with MPV (p = 2.4x10^-13) and rs855791 with MCV (p = 5.2x10^-12). We then examined possible associations between these significant SNPs and incidence of 1,488 phenotype groups mapped from International Classification of Disease version 9 and 10 (ICD9 and ICD10) codes collected in the extensive electronic health record (EHR) database associated with Healthy Nevada Project consented participants. Further leveraging data collected in the EHR, we performed an additional PheWAS to identify associations between continuous red blood cell (RBC) component measures and incidence of specific diagnoses. The first PheWAS illuminated whether SNPs associated with RBC components in our cohort were linked with other hematologic phenotypic diagnoses or diagnoses of other nature. Although no SNPs from our GWAS were identified as strongly associated to other phenotypic components, a number of associations were identified with p-values ranging between 1x10^-3 and 1x10^-4 with traits such as respiratory failure, sleep disorders, hypoglycemia, hyperglyceridemia, GERD and IBS. The second PheWAS examined possible phenotypic predictors of abnormal RBC component measures: a number of hematologic phenotypes such as thrombocytopenia, anemias, hemoglobinopathies and pancytopenia were found to be strongly associated to RBC component measures; additional phenotypes such as (morbid) obesity, malaise and fatigue, alcoholism, and cirrhosis were also identified to be possible predictors of RBC component measures.

Resource Concentration Modulates the Fate of Dissimilated Nitrogen in a Dual-Pathway Actinobacterium

Respiratory ammonification and denitrification are two evolutionarily unrelated dissimilatory nitrogen (N) processes central to the global N cycle, the activity of which is thought to be controlled by carbon (C) to nitrate (NO3 -) ratio. Here we find that Intrasporangium calvum C5, a novel dual-pathway denitrifier/respiratory ammonifier, disproportionately utilizes ammonification rather than denitrification when grown under low C concentrations, even at low C:NO3 - ratios. This finding is in conflict with the paradigm that high C:NO3 - ratios promote ammonification and low C:NO3 - ratios promote denitrification. We find that the protein atomic composition for denitrification modules (NirK) are significantly cost minimized for C and N compared to ammonification modules (NrfA), indicating that limitation for C and N is a major evolutionary selective pressure imprinted in the architecture of these proteins. The evolutionary precedent for these findings suggests ecological importance for microbial activity as evidenced by higher growth rates when I. calvum grows predominantly using its ammonification pathway and by assimilating its end-product (ammonium) for growth under ammonium-free conditions. Genomic analysis of I. calvum further reveals a versatile ecophysiology to cope with nutrient stress and redox conditions. Metabolite and transcriptional profiles during growth indicate that enzyme modules, NrfAH and NirK, are not constitutively expressed but rather induced by nitrite production via NarG. Mechanistically, our results suggest that pathway selection is driven by intracellular redox potential (redox poise), which may be lowered when resource concentrations are low, thereby decreasing catalytic activity of upstream electron transport steps (i.e., the bc1 complex) needed for denitrification enzymes. Our work advances our understanding of the biogeochemical flexibility of N-cycling organisms, pathway evolution, and ecological food-webs.

Localized Delivery of Cl-Amidine From Electrospun Polydioxanone Templates to Regulate Acute Neutrophil NETosis: A Preliminary Evaluation of the PAD4 Inhibitor for Tissue Engineering

Upon interaction, neutrophils can potentially release neutrophil extracellular traps (NETs) on the surface of an implanted electrospun template, which may be a significant preconditioning event for implantable biomaterials of yet unknown consequences. In this study, we investigated the potential of polydioxanone templates as a delivery vehicle for Cl-amidine, an inhibitor of peptidyl arginase deiminase 4 (PAD4), and if drug elution could attenuate PAD4-mediated NETosis in the vicinity of implanted templates. Electrospun polydioxanone templates were fabricated with distinct architectures, small diameter (0.4 μm) or large diameter (1.8 μm) fibers, and incorporated with 0-5 mg/mL Cl-amidine to examine dose-dependent effects. Acute neutrophil-template interactions were evaluated in vitro with freshly isolated human neutrophils and in vivo with a rat subcutaneous implant model. The in vitro results suggest large diameter templates with 0 mg/mL Cl-amidine significantly attenuate NETosis compared to small diameter templates. As the drug concentration increased, NETosis was significantly decreased on small diameter templates in a dose-dependent manner. The opposite was observed for large diameter templates, indicating multiple mechanisms of NETosis may be regulating neutrophil template preconditioning. Similar results were observed in vivo, verifying local NETosis inhibition by Cl-amidine eluting templates in a physiological environment. Importantly, large diameter templates with Cl-amidine enhanced neutrophil invasion and survival, supporting the potential for long-term modulation of tissue integration and regeneration. This preliminary study demonstrates a novel delivery vehicle for Cl-amidine that can be used to regulate acute NETosis as the potential critical link between the innate immune response, inflammation, and template-guided tissue regeneration.

West Nile Virus Encephalitis in a Dog

In November 2002, a 2-year-old, spayed Maltese Terrier in central Mississippi was presented for an acute illness characterized by uncontrolled hyperactivity that rapidly progressed to generalized tremors, ataxia, and intermittent hyperthermia. Postmortem examination after a 2-week course revealed mild, multifocal, nonsuppurative meningo encephalitis, with focal necrosis in the medulla. Reverse transcriptase-nested-polymerase chain reaction for West Nile virus (WNV) was positive on brain and negative on other tissues. Immunohistochemistry was negative on all tissues. The clinical, postmortem, and laboratory findings are consistent with acute encephalitis due to WNV infection. WNV infection should be considered in dogs showing signs of encephalitis when and where WNV and mosquito vectors occur.

Simultaneous measurement of tabun, sarin, soman, cyclosarin, VR, VX, and VM adducts to tyrosine in blood products by isotope dilution UHPLC-MS/MS

This work describes a new specific, sensitive, and rapid stable isotope dilution method for the simultaneous detection of the organophosphorus nerve agents (OPNAs) tabun (GA), sarin (GB), soman (GD), cyclosarin (GF), VR, VX, and VM adducts to tyrosine (Tyr). Serum, plasma, and lysed whole blood samples (50 μL) were prepared by protein precipitation followed by digestion with Pronase. Specific Tyr adducts were isolated from the digest by a single solid phase extraction (SPE) step, and the analytes were separated by reversed-phase ultra high performance liquid chromatography (UHPLC) gradient elution in less than 2 min. Detection was performed on a triple quadrupole tandem mass spectrometer using time-triggered selected reaction monitoring (SRM) in positive electrospray ionization (ESI) mode. The calibration range was characterized from 0.100-50.0 ng/mL for GB- and VR-Tyr and 0.250-50.0 ng/mL for GA-, GD-, GF-, and VX/VM-Tyr (R(2) ≥ 0.995). Inter- and intra-assay precision had coefficients of variation of ≤17 and ≤10%, respectively, and the measured concentration accuracies of spiked samples were within 15% of the targeted value for multiple spiking levels. The limit of detection was calculated to be 0.097, 0.027, 0.018, 0.074, 0.023, and 0.083 ng/mL for GA-, GB-, GD-, GF-, VR-, and VX/VM-Tyr, respectively. A convenience set of 96 serum samples with no known nerve agent exposure was screened and revealed no baseline values or potential interferences. This method provides a simple and highly specific diagnostic tool that may extend the time postevent that a confirmation of nerve agent exposure can be made with confidence.

Nephronophthisis and retinal degeneration in tmem218-/- mice: a novel mouse model for Senior-Løken syndrome?

Mice deficient in TMEM218 (Tmem218(-/-) ) were generated as part of an effort to identify and validate pharmaceutically tractable targets for drug development through large-scale phenotypic screening of knockout mice. Routine diagnostics, expression analysis, histopathology, and electroretinogram analyses completed on Tmem218(-/-) mice identified a previously unknown role for TMEM218 in the development and function of the kidney and eye. The major observed phenotypes in Tmem218(-/-) mice were progressive cystic kidney disease and retinal degeneration. The renal lesions were characterized by diffuse renal cyst development with tubulointerstitial nephropathy and disruption of tubular basement membranes in essentially normal-sized kidneys. The retinal lesions were characterized by slow-onset loss of photoreceptors, which resulted in reduced electroretinogram responses. These renal and retinal lesions are most similar to those associated with nephronophthisis (NPHP) and retinitis pigmentosa in humans. At least 10% of NPHP cases present with extrarenal conditions, which most often include retinal degeneration. Senior-Løken syndrome is characterized by the concurrent development of autosomal recessive NPHP and retinitis pigmentosa. Since mutations in the known NPHP genes collectively account for only about 30% of NPHP cases, it is possible that TMEM218 could be involved in the development of similar ciliopathies in humans. In reviewing all other reported mouse models of NPHP, we suggest that Tmem218(-/-) mice could provide a useful model for elucidating the pathogenesis of cilia-associated disease in both the kidney and the retina, as well as in developing and testing novel therapeutic strategies for Senior-Løken syndrome.

The development of an analytical method for urinary metabolites of the riot control agent 2-chlorobenzylidene malononitrile (CS)

The analysis of biomedical samples such as urine and blood can provide evidence of exposure to chemicals for a range of applications including occupational exposure monitoring, detection of drugs of abuse, performance enhancement in sport and investigations of poisoning and incapacitation. This paper reports the development of an analytical method for two suspected urinary metabolites of the riot control agent 2-chlorobenzylidene malononitrile (CS): 2-chlorohippuric acid and 2-chlorobenzyl-N-acetylcysteine. 2-Chlorohippuric acid was identified in all 2h post-exposure samples from a set of urine samples taken from army recruits exposed to low levels of thermally dispersed CS during training. 2-Chlorobenzyl-N-acetylcysteine, a metabolite known to be formed in the rat, was not identified in any of the samples. The lower limit of detection (LLOD) for 2-chlorohippuric acid and 2-chlorobenzyl-N-acetylcysteine was 1ng/ml and 0.5ng/ml in pooled urine from the pre-exposed subjects. 2-Chlorohippuric acid was rapidly excreted but was detectable in the urine of 17 of the 19 subjects tested 20h after exposure.

Analysis of clothing and urine from Moscow theatre siege casualties reveals carfentanil and remifentanil use

On October 26, 2002, Russian Special Forces deployed a chemical aerosol against Chechen terrorists to rescue hostages in the Dubrovka theatre. Its use confirmed Russian military interest in chemicals with effects on personnel and caused 125 deaths through a combination of the aerosol and inadequate medical care. This study provides evidence from liquid chromatography-tandem mass spectrometry analysis of extracts of clothing from two British survivors, and urine from a third survivor, that the aerosol comprised a mixture of two anaesthetics--carfentanil and remifentanil--whose relative proportions this study was unable to identify. Carfentanil and remifentanil were found on a shirt sample and a metabolite called norcarfentanil was found in a urine sample. This metabolite probably originated from carfentanil.

Amelogenesis imperfecta and other biomineralization defects in Fam20a and Fam20c null mice

The FAM20 family of secreted proteins consists of three members (FAM20A, FAM20B, and FAM20C) recently linked to developmental disorders suggesting roles for FAM20 proteins in modulating biomineralization processes. The authors report here findings in knockout mice having null mutations affecting each of the three FAM20 proteins. Both Fam20a and Fam20c null mice survived to adulthood and showed biomineralization defects. Fam20b (-/-) embryos showed severe stunting and increased mortality at E13.5, although early lethality precluded detailed investigations. Physiologic calcification or biomineralization of extracellular matrices is a normal process in the development and functioning of various tissues (eg, bones and teeth). The lesions that developed in teeth, bones, or blood vessels after functional deletion of either Fam20a or Fam20c support a significant role for their encoded proteins in modulating biomineralization processes. Severe amelogenesis imperfecta (AI) was present in both Fam20a and Fam20c null mice. In addition, Fam20a (-/-) mice developed disseminated calcifications of muscular arteries and intrapulmonary calcifications, similar to those of fetuin-A deficient mice, although they were normocalcemic and normophosphatemic, with normal dentin and bone. Fam20a gene expression was detected in ameloblasts, odontoblasts, and the parathyroid gland, with local and systemic effects suggesting both local and/or systemic effects for FAM20A. In contrast, Fam20c (-/-) mice lacked ectopic calcifications but were severely hypophosphatemic and developed notable lesions in both dentin and bone to accompany the AI. The bone and dentin lesions, plus the marked hypophosphatemia and elevated serum alkaline phosphatase and FGF23 levels, are indicative of autosomal recessive hypophosphatemic rickets/osteomalacia in Fam20c (-/-) mice.

Ocular albinism and hypopigmentation defects in Slc24a5-/- mice

As part of a high-throughput mutagenesis and phenotyping process designed to discover novel drug targets, we generated and characterized mice with a targeted mutation in Slc24a5, a gene encoding a putative cation exchanger. Upon macroscopic examination, Slc24a5-/- mice were viable, fertile, and indistinguishable by coat color from their heterozygous and wild-type litter mates. Ophthalmoscopic examination revealed diffuse retinal hypopigmentation, and a histologic examination of the eye confirmed the presence of moderate-to-marked hypopigmentation of the retinal pigmented epithelium (RPE), ciliary body, and iris pigment epithelium (IPE). Hypopigmentation was most severe in the anterior layer cells of the IPE, where melanosomes were smaller, paler, and more indistinct than those of the anterior stroma and posterior IPE. The pigment granules of the posterior IPE appeared to be nearly as dark as those in stromal melanocytes; however, both cell layers were thinner and paler than corresponding layers in wild-type mice. Ultrastructural analysis of the RPE, IPE, and ciliary body pigmented cells confirmed that mutation of Slc24a5 results in marked hypopigmentation of melanosomes in optic cup-derived pigmented neuroepithelium in the eyes. Milder reductions in melanosome size and pigmentation were noted in neural crest-derived melanocytes. The severe hypopigmentation of neuroepithelium-derived cells in the eyes resulted in a novel form of ocular albinism in Slc24a5-/- mice. Our findings suggest that SLC24A5 may be a candidate gene for some forms of ocular albinism and for the BEY1/EYCL2 locus previously associated with central brown eye color in humans.

Phosphylated tyrosine in albumin as a biomarker of exposure to organophosphorus nerve agents

The organophosphorus nerve agents sarin, soman, cyclosarin and tabun phosphylate a tyrosine residue on albumin in human blood. These adducts may offer relatively long-lived biological markers of nerve agent exposure that do not 'age' rapidly, and which are not degraded by therapy with oximes. Sensitive methods for the detection of these adducts have been developed using liquid chromatography-tandem mass spectrometry. Adducts of all four nerve agents were detected in the blood of exposed guinea pigs being used in studies to improve medical countermeasures. The tyrosine adducts with soman and tabun were detected in guinea pigs receiving therapy 7 days following subcutaneous administration of five times the LD(50) dose of the respective nerve agent. VX also forms a tyrosine adduct in human blood in vitro but only at high concentrations.

Analysis of the sulphur mustard metabolites thiodiglycol and thiodiglycol sulphoxide in urine using isotope-dilution gas chromatography–ion trap tandem mass spectrometry

A sensitive method has been developed for the trace analysis of the sulphur mustard metabolite thiodiglycol (TDG) in urine, and its oxidation product thiodiglycol sulphoxide (TDGO) after reduction to thiodiglycol. Thiodiglycol was extracted from urine by solid phase extraction onto a polymeric cartridge and, after isolation, converted to its bis-heptafluorobutyryl derivative with heptafluorobutyryl imidazole. An ion trap mass spectrometer in selected reaction monitoring mode detected spiked concentrations down to 0.2 ng/ml with a signal to noise ratio>3:1. Urine, from human volunteers with no known exposure to sulphur mustard, contained detectable but very low concentrations (<0.2 ng/ml) of thiodiglycol, consistent with previous observations using different methodologies. Combined concentrations of thiodiglycol and thiodiglycol sulphoxide were determined after reduction of the latter with titanium trichloride. In this case higher background levels (up to 3 ng/ml) were observed, consistent with the sulphoxide being the major excretion product of the two metabolites. The method was applied to urine samples, stored frozen for 13 years, from two casualties of accidental mustard poisoning. Levels of thiodiglycol were 1 and 3 ng/ml, which increased to 78 and 104 ng/ml after treatment of the urine with titanium trichloride.

Histologic Comparison of Canine Skin Biopsies Collected Using Monopolar Electrosurgery, CO2Laser, Radiowave Radiosurgery, Skin Biopsy Punch, and Scalpel

OBJECTIVE

To compare the histologic appearance of canine skin biopsies collected by use of a scalpel, skin biopsy punch, monopolar electrosurgery, CO2 laser, and radio wave radiosurgery in fully rectified wave form (RWRS).

STUDY DESIGN

Experimental, randomized design.

ANIMALS

Healthy adult grayhounds (n=4).

METHODS

Skin biopsies were collected using 5 techniques. Cut margins of biopsy specimens and adjacent peripheral skin were evaluated using light microscopy to compare penetration of the dermis by tissue carbonization (char).

RESULTS

No char occurred in skin specimens collected by biopsy punch and scalpel. Char penetration occurred in all specimens collected by electrosurgery, CO2 laser, and RWRS. Mean char penetration in skin biopsies collected by RWRS (0.158 mm) was significantly less than for monopolar electrosurgery (0.223 mm) and CO2 laser (0.215 mm). Mean char penetration in adjacent peripheral skin surrounding biopsies collected by RWRS (0.171 mm) was significantly less than monopolar electrosurgery (0.255 mm) but not less than CO2 laser (0.215 mm, P<.07).

CONCLUSIONS

RWRS (blended waves in cut-coagulate mode) caused less lateral thermal damage to canine skin biopsies than monopolar electrosurgery and CO2 laser and less lateral thermal injury to peripheral skin than monopolar electrosurgery.

CLINICAL RELEVANCE

Excision of canine skin biopsies with heat-generating devices may not allow reliable histologic interpretation, particularly when assessing margins of small biopsy specimens. RWRS may be less traumatic to canine skin than monopolar electrosurgery and CO2 laser when used to make incisions.

The trace analysis of alkyl alkylphosphonic acids in urine using gas chromatography-ion trap negative ion tandem mass spectrometry

A sensitive method has been developed for the trace analysis of alkyl alkylphosphonic acids, metabolites of nerve agents, in urine using a benchtop ion trap mass spectrometer. The acids were isolated from urine by simple solid phase extraction and converted to their pentafluorobenzyl esters. An ion trap mass spectrometer in selected reaction monitoring mode provided limits of detection of 0.1 ng/ml for isopropyl, isobutyl, pinacolyl and cyclohexyl methylphosphonic acids and for ethyl ethylphosphonic acid. The detection limit for ethyl methylphosphonic acid was higher (0.5 ng/ml) due to a lower recovery.

Analysis of β-Lyase Metabolites of Sulfur Mustard in Urine by Electrospray Liquid Chromatography-Tandem Mass Spectrometry

A method is described for the analysis of b-lyase metabolites of sulfur mustard, 1-methylsulfinyl-2- [2-(methylthio)ethylsulfonyl]ethane and 1,1'-sulfonylbis [2-(methylsulfinyl)ethane], in human urine. The analytes were concentrated from urine on an ENV+ solid-phase extraction cartridge and analyzed by liquid chromatography-positive ion electrospray-tandem mass spectrometry in the selected reaction monitoring mode. Quantitation was performed against deuterated internal standards. Limits of detection were 0.1-0.5 ng/mL. The metabolites were detected in samples of urine from human casualties of sulfur mustard poisoning. The method provides a simpler alternative to gas chromatography-tandem mass spectrometry analysis, avoiding the need for reduction to less polar analytes.

Analysis of the Sulfur Mustard Metabolite 1,1′-Sulfonylbis[2-S-(N-acetylcysteinyl)ethane] in Urine by Negative Ion Electrospray Liquid Chromatography-Tandem Mass Spectrometry

A method is described for the analysis of the sulfur mustard metabolite 1,1'-sulfonylbis[2-S-(N-acetylcysteinyl)ethane] in human urine. The analyte was concentrated from urine on a polymeric SPE cartridge and analyzed by liquid chromatography-negative ion electrospray tandem mass spectrometry in the selected reaction monitoring mode. The limit of detection was 0.5-1 ng/mL. The metabolite was detected at concentrations close to the detection limit in samples of urine from two casualties accidentally exposed to sulfur mustard from a First World War munition.

Identification of iso- and n-propylphosphonates using liquid chromatography–tandem mass spectrometry and gas chromatography–Fourier transform infrared spectroscopy

Organophosphorus nerve agents and their precursors, specifically listed in the schedules of chemicals in the Annex to the Chemical Weapons Convention (CWC), include analogues with C1-C3 alkyl groups on phosphorus. The Organisation for the Prohibition of Chemical Weapons (OPCW) requires designated laboratories to unequivocally identify isomeric propyl groups bonded to phosphorus in analytes that may be present in samples submitted for analysis. Homologous series of isomeric pairs of dialkyl iso- and n-propylphosphonates, alkyl iso- and n-propylphosphonochloridates, and alkyl iso- and n-propylphosphonofluoridates, have been analysed by liquid chromatography-ion trap tandem mass spectrometry and/or by gas chromatography-Fourier transform infrared spectroscopy. The results show that P-propyl isomers can be reliably differentiated by collision induced dissociation (CID) of selected fragment ions and by their infrared P=O stretching and C-H deformation frequencies.

Association between orbital fracture location and ocular injury: a retrospective study

BACKGROUND

Orbital fractures are frequently accompanied by ocular injury. Any findings that provide information for diagnosing a concurrent ocular injury should improve patient care. A greater incidence of severe ocular injury with certain fracture types was hypothesized, based on orbital wall thickness.

METHODS

A retrospective review of 87 consecutive patients (107 fractured orbits) was performed by the Ophthalmology Department of an urban Level 1 trauma center.

RESULTS AND CONCLUSIONS

Severe injuries were associated with orbital apex fractures (p = 0.00001), with lateral wall fractures (p < 0.04), and with Le Fort Type III fractures (p < 0.02). Moderate injuries were associated with isolated orbital floor fractures (p < 0.01). Apex, lateral wall, and Le Fort Type III fractures have a greater association with severe ocular injuries than other fracture types.

Metastatic adenocarcinoma with rupture through the Bruch membrane simulating a choroidal melanoma

PURPOSE

To report a case of adenocarcinoma metastatic to the choroid with rupture through the Bruch membrane, thus, simulating a choroidal melanoma.

METHODS

Interventional case report. Evaluation in a university-based clinic, including a complete eye examination, fluorescein angiography, and ultrasonography; oncological evaluation; and eventual enucleation with histopathological study, including immunohistochemical stains.

RESULTS

A 62-year-old Hispanic female presented with visual loss, right eye, of short duration because of a choroidal mass with retinal detachment. Ultrasonography showed a dome-shaped lesion with an eccentric collar-button projection and medium internal reflectivity, which suggested a choroidal melanoma. Initial systemic evaluation was negative. Severe pain necessitated enucleation, RE, and histopathology of the choroidal mass demonstrated an adenocarcinoma. Further examination revealed a left, upper lobe, nonsmall cell lung carcinoma.

CONCLUSION

Metastatic choroidal tumors may present, although rarely, with collar-button configurations.

An outbreak of trematode-induced granulomas of the conjunctiva

PURPOSE

To describe the epidemiologic, clinical, and histopathologic features of trematode granulomas of the conjunctiva, eyelid, and anterior chamber in pediatric patients.

DESIGN

Prospective noncomparative case series.

PARTICIPANTS

Forty-one children from a southern Indian village with conjunctival granulomas.

METHODS

The village of Sellananthal was selected for a field visit after analysis of earlier hospital-based allergic conjunctival granuloma cases. Children with ocular diseases were examined, and histories of exposure to assumed risk factors and clinical findings were evaluated. Selected patients were brought to the base hospital for excisional biopsy. Serial sections obtained from the excised nodules were examined for the presence of a parasite.

MAIN OUTCOME MEASURES

Histopathologic examination of excised conjunctival lesions or response of lesions to local medical therapy.

RESULTS

In this year-long prospective study, 41 children (16 years or younger; 38 boys and 3 girls) with clinical features of allergic conjunctival granulomas were examined. Thirty-four patients were from a single village located in the southern Indian state of Tamil Nadu; the remaining 7 were from various parts of the same state. All children swam in their village's freshwater pond. Twenty patients with nodules less than 5 mm in diameter received medical treatment; 13 with larger nodules underwent surgical excision of the lesions. Nine of these 13 cases revealed a zonal granulomatous inflammation admixed with eosinophilic leukocytes; 4 of these 9 displayed fragments of the tegument and internal structures of a trematode and Splendore-Hoeppli phenomenon. The remaining 4 of the 13 cases revealed nongranulomatous inflammation made up of lymphocytes, histiocytes, and eosinophils. Eight patients refused surgical treatment.

CONCLUSIONS

In southern India, one cause of allergic conjunctival granulomas in children seems to be trematode infection. The clustering of cases in a single village and exposure to a village freshwater pond indicate the need for an epidemiologic investigation and study of the parasite's life cycle. Sporadic cases from other parts of the state with similar histories of exposure to their local pond or river water suggest a widespread distribution of the etiologic agent.

Fluorous Boc ((F)Boc) carbamates: new amine protecting groups for use in fluorous synthesis

The first fluorous variants of the Boc (tert-butyloxycarbonyl) group have been prepared and tested for their suitability as nitrogen protecting groups. A group with two fluorous chains and an ethylene spacer, (RfCH2CH2)2(CH3)COC(O)-, was readily attached to a representative amine but was difficult to cleave. In contrast, groups with two fluorous chains and a propylene spacer, (RfCH2CH2CH2)2(CH3)COC(O)-, or one fluorous chain and an ethylene spacer, (RfCH2CH2)(CH3)2COC(O)-, were readily formed and cleaved. The fluorous alcohol component of the (F)Boc group can be removed by evaporation and can be recovered and reused. The utility of the new (F)Boc group (C8F17CH2CH2)(CH3)2COC(O)- was demonstrated in 16 and 96 compound library synthesis exercises. Separations can be achieved either by manual, parallel fluorous solid-phase extraction, or automated, serial fluorous chromatography. The results provide additional confirmation of the value of "light" fluorous synthesis techniques, and the new fluorous Boc groups expand the applicability of fluorous synthesis techniques to many classes of nitrogen-containing organic compounds.

Complications and prognostic factors in Vogt-Koyanagi-Harada disease

PURPOSE

To identify associations between complications of disease and final visual acuity in patients with Vogt-Koyanagi-Harada disease and to identify prognostic factors for disease outcome.

METHODS

All patients diagnosed with Vogt-Koyanagi-Harada disease at the Doheny Eye Institute or the Los Angeles County/University of Southern California Medical Center between 1983 and 1997 were reviewed. Data extracted included initial and final visual acuities, age, gender, ethnicity, complications, treatment, duration of disease, and number of recurrences.

RESULTS

One hundred one patients with Vogt-Koyanagi-Harada disease were identified, 68 (67%) of which were female. Mean age was 34 +/- 14 years (range, 8 to 75 years). Asians presented at a significantly older age than all other groups. One hundred three eyes (51%) developed at least one complication, including cataract in 84 eyes (42%), glaucoma in 54 eyes (27%), choroidal neovascular membranes in 22 eyes (11%), and subretinal fibrosis in 13 eyes (6%). Patients who developed at least one complication had a significantly longer median duration of disease and number of recurrent episodes of inflammation (P =.0001 for each) than did those patients who developed no complications. Statistically significant associations existed between poor final visual acuity and greater numbers of complications (P =.001), greater age at onset (P =.03), a longer median duration of disease (P =.03), and greater number of recurrent episodes of inflammation (P =.0004). Eyes possessing a better visual acuity at presentation were more likely to have a better visual acuity at final follow-up (P =.001).

CONCLUSIONS

Factors associated with a worse final acuity included increasing numbers of complications, greater age at onset, and worse acuity at presentation.

Revised diagnostic criteria for Vogt-Koyanagi-Harada disease: report of an international committee on nomenclature

PURPOSE

To present revised criteria for the diagnosis of Vogt-Koyanagi-Harada disease, a chronic, bilateral, granulomatous ocular and multisystem inflammatory condition of unknown cause.

METHODS

Diagnostic criteria and nomenclature were subjects of discussion at the First International Workshop on Vogt-Koyanagi-Harada Disease on October 19-21, 1999, at the University of California, Los Angeles, Conference Center, Lake Arrowhead, California. A committee appointed by the workshop participants was charged with drafting revised criteria for Vogt-Koyanagi-Harada disease, based on discussions held during the conference. This article is the consensus committee report.

RESULTS

New criteria, taking into account the multisystem nature of Vogt-Koyanagi-Harada disease, with allowance for the different ocular findings present in the early and late stages of the disease, were formulated and agreed upon by the committee. These criteria are based on additional knowledge and experience of experts in the field and are believed to reflect disease features more fully than previously published criteria.

CONCLUSIONS

The revised definition of Vogt-Koyanagi-Harada disease, with expanded diagnostic criteria, will facilitate performance of studies involving homogeneous populations of patients, at various stages of disease, that address unanswered questions regarding treatment and disease mechanisms.

Rifabutin-associated hypopyon uveitis in human immunodeficiency virus-negative immunocompetent individuals

OBJECTIVE

To report the occurrence of rifabutin-associated hypopyon uveitis in human immunodeficiency virus (HIV)-negative immunocompetent individuals.

DESIGN

Retrospective case series.

PARTICIPANTS

Three HIV-negative subjects on rifabutin and clarithromycin for Mycobacterium avium complex infections with hypopyon uveitis are described. One subject was iatrogenically immunosuppressed because of a prior lung transplant. Two subjects had no known immunosuppressive conditions.

INTERVENTION

Topical and regional steroid therapy. Discontinuation of rifabutin was required in two subjects.

MAIN OUTCOME MEASURES

Visual acuity, resolution of hypopyon, anterior uveitis, and vitreitis.

RESULTS

All subjects had resolution of hypopyon after therapy, two within 24 hours of beginning topical steroids. Vitreitis resolved with the discontinuation of rifabutin in two subjects. Chronic low-grade anterior uveitis and vitreitis were observed in the remaining subject, whose rifabutin dose was lowered but not discontinued because of active Mycobacterium avium complex osteomyelitis.

CONCLUSIONS

Rifabutin-associated uveitis is well described in HIV-positive individuals, but it has been reported only once in an HIV-negative individual. We report two cases of hypopyon uveitis in immunocompetent individuals and one case in an immunosuppressed HIV-negative individual. All three subjects were receiving concurrent rifabutin and clarithromycin. Awareness that this entity can occur in HIV negative and nonimmunosuppressed individuals and that it can mimic infectious endophthalmitis may spare the subject from an invasive workup of systemic infection.

Rhabdomyomatous mesenchymal hamartoma of the eyelid: report of a case and literature review

PURPOSE

To report a rare case of rhabdomyomatous mesenchymal hamartoma and to compare its features with those cases previously reported.

DESIGN

Interventional case report and literature review.

INTERVENTION

Complete ophthalmologic and systemic examinations followed by excisional biopsy and histopathologic examination.

MAIN OUTCOME MEASURES

Clinical examination features and histopathologic findings.

RESULTS

A 6-month-old Latino male presented with a congenital, elevated, smooth, flesh-colored right lower eyelid lesion. An ipsilateral right limbal dermoid and an upper eyelid coloboma were also present. Excisional biopsy of the eyelid lesion revealed randomly oriented mature striated muscle tissue with associated adipose tissue, blood vessels, pilosebaceous units, and peripheral nerves, findings consistent with rhabdomyomatous mesenchymal hamartoma. Of the 24 reported cases (including the current case), eight had associated congenital anomalies.

CONCLUSIONS

Although rhabdomyomatous mesenchymal hamartomas are rare and benign, they may be associated with other congenital anomalies and anomaly syndromes. As a result, we recommend systemic evaluation of patients diagnosed with this entity.

Self-inflicted anterior scleritis

PURPOSE

To describe and clinically characterize a syndrome of self-inflicted scleritis.

STUDY DESIGN

Case reports and literature review.

METHODS

Two patients had persistent scleritis at presentation. Both did not respond to prescribed therapy, including systemic corticosteroids and immunosuppression. The first had unexplained, diffuse anterior scleritis and persistent linear keratoconjunctival abrasions after a work-related injury. Several objective indicators pointed to concealed noncompliance with medications. The second patient was a medical assistant with diffuse, unilateral anterior scleritis and unexplained visual loss. Systemic work-up was negative. She had pharmacologic mydriasis and keratoconjunctival abrasions at presentation.

RESULTS

Systemic therapy was stopped in both patients. The first patient, who was in the process of requesting permanent disability status, showed persistent inflammation on each follow-up visit. The second patient improved with no further therapy after she was confronted with objective indicators of a self-inflicted condition.

CONCLUSIONS

Although the presentation of self-inflicted scleritis can be similar to that of idiopathic or autoimmune anterior scleritis, the former may show additional findings of traumatic conjunctival and corneal abrasions. Indicators of self-inflicted etiology, of which malingering is one such entity, include evidence of concealed noncompliance with prescribed treatments and lack of response to potent antiinflammatory and immunosuppressive agents. Correct diagnosis including early psychiatric evaluation in all such cases, may help prevent unnecessary treatment and unjustified work-related compensation.

Vogt-Koyanagi-Harada disease

Vogt-Koyanagi-Harada (VKH) disease affects primarily persons who are Asian, Latino, Native American, or Asian Indian. Women appear to be affected more commonly than men, and VKH disease may occur at all ages, including childhood. Experimental data continue to support an autoimmune etiology for VKH disease, directed most probably against an antigenic component of the melanocyte, possibly tyrosinase or a tyrosinase-related protein. The clinical diagnosis of VKH disease continues to be based on physical findings. Newer imaging modalities such as magnetic resonance imaging, indocyanine green angiography, and digital image analysis have not added appreciably to our understanding of the condition. First-line therapy consists of high-dose corticosteroids, with use of corticosteroid-sparing agents for resistant or recalcitrant disease. Complications are the main cause of reversible and irreversible vision loss, with subretinal fibrosis and choroidal neovascular membranes having particularly poor prognoses.

Utility of existing Vogt-Koyanagi-Harada syndrome diagnostic criteria at initial evaluation of the individual patient: a retrospective analysis

The diagnosis of Vogt-Koyanagi-Harada syndrome is hampered by its variable manifestations and the lack of unique ancillary and laboratory findings. In this study, the diagnostic criteria established in 1978 by the American Uveitis Society (AUS) are retrospectively analyzed via their application to a population of 71 consecutive patients, using only those features present at the initial evaluation. All patients were previously diagnosed with Vogt-Koyanagi-Harada syndrome based on the clinical features and course of the disease combined with fluorescein angiography with or without ultrasonography in selected cases. Mean age of all patients was 36.7 years +/- 15.1 years. Fifty (70%) were female and 45 (65%) were Hispanic. Patients presenting acutely, subacutely, and in the chronic stages met the AUS criteria for Vogt-Koyanagi-Harada syndrome in 56%, 48%, and 58% of cases, respectively. Allowance for variation in features, incomplete cases, and modification of the disease by treatment might increase the sensitivity of the criteria. While diagnostic criteria in general are useful for establishing the likelihood that a patient has a disease, the current AUS criteria for the diagnosis of Vogt-Koyanagi-Harada syndrome do not seem adequate.

Peroxynitrite formation in the orbit of diabetics with rhinocerebral mucormycosis

OBJECTIVE

To evaluate whether an intact respiratory burst exists within the orbit of diabetics with rhinocerebral mucormycosis.

METHODS

Immunohistochemical detection of nitrotyrosine in the orbital tissue of diabetics requiring exenteration due to rhinocerebral mucormycosis. Nitrotyrosine is the stable product of the nitration of tyrosine residues by peroxynitrite. Peroxynitrite is a potent oxidant produced by the combination of superoxide and nitric oxide during the respiratory burst.

RESULTS

Four specimens were analyzed. All showed focal areas of specific staining against nitrotyrosine of the walls and internal structures of fungal organisms.

CONCLUSIONS

An intact respiratory burst is present in the orbit of diabetics during infection with rhinocerebral mucormycosis. Possible mechanisms of peroxynitrite's microbicidal effects and reasons for a deficiency in diabetics are discussed.

Traumatic Acremonium atrogriseum keratitis following laser-assisted in situ keratomileusis

A 52-year-old man underwent bilateral laser-assisted in situ keratomileusis. Eight months later, he sustained a penetrating corneal injury to the left eye. A dense white infiltrate, unresponsive to antimicrobial therapy, developed in the corneal stroma. Corneal biopsy and eventual penetrating keratoplasty were performed, and both specimens demonstrated fungal elements with branching, septate hyphae. Culture identified the organism as Acremonium atrogriseum. Histopathologic features of this organism and its differentiation from other, more common fungal organisms are discussed herein.

Episcleritis in childhood

OBJECTIVE

To describe the characteristics and systemic disease associations of episcleritis in childhood.

DESIGN

Retrospective, observational case series.

PARTICIPANTS

Twelve children diagnosed with episcleritis between July 1981 and June 1998. METHODS/TESTING: Complete eye and systemic evaluations.

MAIN OUTCOME MEASURES

Characteristics of episcleritis and presence and nature of concurrent systemic disease.

RESULTS

The 12 children (10 boys and 2 girls) ranged in age from 13 months to 16 years. Five children had bilateral simple episcleritis, one had bilateral nodular episcleritis, and six had unilateral simple episcleritis. The eye examination was otherwise normal and recovery was uneventful in all cases. Six of the nine children older than 5 years of age had one of the following rheumatologic diseases: systemic lupus erythematosus, juvenile rheumatoid arthritis, spondyloarthropathy, inflammatory bowel disease, rheumatic fever, or polyarteritis nodosa. All three children younger than 5 years of age had simple episcleritis, an antecedent viral illness, and presented within 2 months of each other.

CONCLUSIONS

Episcleritis is a rare occurrence in childhood, especially in children younger than 5 years of age. In older children, it is frequently associated with rheumatologic disease.

Evaluation of the role of human retinal vascular endothelial cells in the pathogenesis of CMV retinitis

Previous studies of cytomegalovirus (CMV) retinitis have failed to definitively explain the exact mechanism by which CMV gains access to and initiates infection in the retina. Proposed theories have included leakage of the virus through vessels with altered permeability, with subsequent infection of surrounding glial cells. In an attempt to shed further light on this subject, a histopathologic examination of 30 autopsy eyes from patients with known systemic CMV disease was carried out using light microscopy, immunohistochemical and immunofluorescent techniques, and in-situ hybridization. Dual-staining methods were used to identify the exact cell type showing the presence of CMV antigens, namely vascular endothelial cells, glial cells, neuronal cells, and/or leukocytes. In those eyes with CMV retinitis, the sites of full-thickness retinal necrosis revealed viral presence mostly within Müller cells and perivascular glial cells, with focal areas of positive staining within retinal pigment epithelial cells (RPE) and neuronal cells. The retinal capillaries were devoid of endothelial cells in these areas. Adjacent to regions of full-thickness necrosis, some vessels showed the presence of a viral antigen within the endothelial cells. These findings suggest that retinal vascular endothelial cells can be infected with CMV. It can further be hypothesized that infection of vascular endothelial cells leads to infection of the surrounding glial and neuronal cells, with eventual spread to the RPE. Endothelial cells might not be present in areas of full-thickness necrosis due to mechanical forces from adjacent blood flow resulting in the sloughing of these cells.

Rapid screening procedures for the hydrolysis products of chemical warfare agents using positive and negative ion liquid chromatography-mass spectrometry with atmospheric pressure chemical ionisation

Qualitative screening procedures have been developed for the rapid detection and identification of the hydrolysis products of chemical warfare agents in aqueous samples and extracts, using liquid chromatography-mass spectrometry with positive and negative atmospheric pressure chemical ionisation (APCI). Previously reported screening procedures, which used positive APCI or electrospray ionisation (ESI), were modified by using LC conditions that allowed acquisition of positive and negative ion mass spectra. APCI was generally found to be more robust than ESI, probably due to variable adduct ion formation with ESI, depending on the condition of the sample and the system. Negative APCI provided selective detection of acidic analytes and allowed facile differentiation of alkyl alkylphosphonic acids from isomeric dialkyl alkylphosphonates. The combination of positive and negative APCI, using a C18 column and water-methanol mobile phase modified with ammonium formate, provides a rapid screening procedure for chemical warfare agent degradation products, with limits of detectability in the range 10-100 ng/ml. In the case of proficiency test samples, where analyte concentrations are in the range 1-10 ppm, introduction of the sample by infusion may provide an even faster preliminary screening procedure.