Eastern equine encephalitis in Tennessee: 2002-2008

Human and equine outbreaks caused by eastern equine encephalomyelitis virus (EEEV) typically occur in North America adjacent to coastal wetlands associated with the presence of Culiseta melanura (Coquillet) mosquitoes. Eastern equine encephalomyelitis (EEE) is an emerging disease in Tennessee, as the first records of equine disease began in 2002. In 2006 we trapped and tested mosquitoes for EEEV at hardwood swamps in western Tennessee that were at the epicenter of a multi-equine outbreak in fall of 2005. Additionally, the Tennessee Valley Authority tested mosquito pools collected in Tennessee swamps from 2000 to 2007 for the presence of arboviruses. Two pools of EEEV positive Culex erraticus (Dyer and Knab) mosquitoes were found (one each in 2003 and 2004) in a county adjacent to where the 2005 outbreak occurred. In 2008, another EEE outbreak involving multiple horses occurred in West Tennessee. A brain specimen was collected from a horse during this outbreak and the first isolate of EEEV from Tennessee was obtained. In total, 74,531 mosquitoes collected from 2000 to 2008 were tested via polymerase chain reaction and VecTest for EEEV. The traditional enzootic vector, Cs. melanura, was found in low numbers at all collection sites. Cx. erraticus, however, was consistently found in high numbers and was the only mosquito species in which EEEV was detected. We suggest that EEE transmission may be maintained by Cx. erraticus in a nontraditional cycle. We discuss the importance of a nontraditional cycle from the perspective of EEEV adaptation and emergence.     

Racial and ethnic disparities in United States: stillbirth rates: trends, risk factors, and research needs

As with most adverse health outcomes, there has been long standing and persistent racial and ethnic disparity for stillbirth in the United States. In 2005, the stillbirth rate (fetal deaths ≥ 20 weeks' gestation per 1000 fetal deaths and live births) for non-Hispanic blacks was 11.13 compared with 4.79 for non-Hispanic whites. Rates were intermediate for American Indian or Alaska Natives (6.17) and Hispanics (5.44). There is racial disparity for both early (< 28 weeks' gestation) and late stillbirths. We review available data regarding risk factors for stillbirth with a focus on those factors that are more prevalent in certain racial/ethnic groups and those factors that appear to have a more profound effect in certain racial/ethnic groups. Although many factors, including genetics, environment, stress, social issues, access to and quality of medical care and behavior, contribute to racial disparity in stillbirth, the reasons for the disparity remain unclear. Knowledge gaps and recommendations for further research and interventions intended to reduce racial disparity in stillbirth are highlighted.     

The primary neutralization epitope of porcine respiratory and reproductive syndrome virus strain VR-2332 is located in the middle of the GP5 ectodomain

Summary.  Pigs infected with porcine respiratory and reproductive syndrome virus (PRRSV) strain VR-2332 were found to generate high levels of antibodies (Abs) that bound in an indirect ELISA to synthetic peptides representing segments of the primary envelope glycoprotein (GP5) ectodomain of this virus. Use of overlapping GP5 ectodomain peptides of various length indicated that the epitope recognized by the Abs was located in the middle of the ectodomain (amino acids 36-52), in the same relative segment that contains the single linear neutralization epitope of the closely related mouse arterivirus, lactate dehydrogenase-elevating virus (LDV). The VR-2332 GP5 segment exhibits 77% amino acid homology with the corresponding GP5 ectodomain segments of both the European PRRSV strain Lelystad virus (LV) and LDV. This explains some observed crossreaction between the pig Abs and neutralizing anti-LDV monoclonal Abs with peptides representing the GP5 ectodomains of VR-2332, LV and LDV. The GP5 binding Abs of pigs seem to be the primary PRRSV neutralizing Abs, since the well timed appearance in sera of all VR-2332 infected pigs of GP5 peptide binding Abs correlated 100% with the appearance of neutralizing Abs and earlier studies indicated that GP5 of PRRSV, like that of other arteriviruses, contains the main neutralization epitope of PRRSV. In addition, one neutralizing anti-LDV monoclonal Ab that is specific for the GP5 ectodomain epitope of LDV also strongly neutralized both PRRSV strains, VR-2332 and LV. The PRRSV GP5 epitope is associated with an N-glycan that is conserved in both PRRSV genotypes and all LDV isolates. This N-glycan may impede the humoral immune control of PRRSV in infected pigs and might be responsible for the low immunogenicity of PRRSV when injected into mice. Received April 2, 2002; accepted July 9, 2002     

Frontal EEG delta/alpha ratio and screening for post-stroke cognitive deficits: The power of four electrodes

This study analysed correlations between post-stroke, quantitative electroencephalographic (QEEG) indices, and cognition-specific, functional outcome measures. Results were compared between QEEG indices calculated from the standard 19 versus 4 frontal (or 4 posterior) electrodes to assess the feasibility and efficacy of employing a reduced electrode montage. Resting-state EEG was recorded at the bedside within 62–101 h after onset of symptoms of middle cerebral artery, ischaemic stroke (confirmed radiologically). Relative power for delta, theta, alpha and beta, delta/alpha ratio (DAR) and pairwise-derived brain symmetry index (pdBSI) were averaged; over all electrodes (global), over F3, F4, F7, F8 (frontal) and P3, P4, T5, T6 (posterior). The functional independence measure and functional assessment measure (FIM–FAM) was administered at mean 105 days post-stroke. Total (30 items) and cognition-specific (5 items) FIM–FAM scores were correlated with QEEG indices using Spearman's coefficient, with a Bonferroni correction. Twenty-five patients were recruited, 4 died within 3 months and 1 was lost to follow-up. Hence 20 cases (10 female; 9 left hemisphere; mean age 68 years, range 38–84) were analysed. Two QEEG indices demonstrated highly-significant correlations with cognitive outcomes: frontal DAR (ρ = − 0.664, p ≤ 0.001) and global, relative alpha power (ρ = 0.67, p ≤ 0.001). After correction there were no other significant correlations. Alpha activity – particularly frontally – may index post-stroke attentional capacity, which appears to be a key determinant of functional and cognitive outcomes. Likewise frontal delta pathophysiology influences such outcomes. Pending further studies, DAR from 4 frontal electrodes may inform early screening for post-MCA stroke cognitive deficits, and thereby, clinical decisions.     

Detection of chromosomes and estimation of aneuploidy in human spermatozoa using fluorescence in-situ hybridization

The development and application of fluorescence in-situ hybridization (FISH) has opened the way for comprehensive studies on numerical chromosome abnormalities in human spermatozoa. FISH can be rapidly applied to large numbers of spermatozoa and thus overcomes the major limitation of karyotyping spermatozoa after penetration of zona-free hamster oocytes. The simultaneous hybridization of two or more chromosome-specific probes to spermatozoa and subsequent detection of the bound probes using different fluorescent detection systems enables two or more chromosomes to be localized simultaneously in the same spermatozoon and provides a technique for undertaking reasonable estimates of aneuploidy. The most commonly used probes are those which bind to the centromeric region of specific chromosomes. Most studies to date have concentrated on estimating aneuploidy in spermatozoa from normospermic men, although reports are beginning to appear on aneuploidy in spermatozoa from subfertile and infertile men. Multi- probe FISH studies have generally reported disomy (hyperhaploidy) estimates of 0.05-0.2% per chromosome. There is preliminary evidence that some chromosomes such as X, Y and 21 are predisposed towards higher rates of non-disjunction during spermatogenesis. There are also suggestions of inter-donor variability in aneuploidy frequencies for specific chromosomes, although this requires confirmation in larger studies. While FISH is clearly a powerful technique that has many applications in reproductive medicine, it must also be realized that it does have limitations and the technology itself is still evolving and has yet to be fully validated on spermatozoa.      

Identification of MEN1 gene mutations in sporadic carcinoid tumors of the lung

Lung carcinoids occur sporadically and rarely in association with multiple endocrine neoplasia type 1 (MEN1). There are no well defined genetic abnormalities known to occur in these tumors. We studied 11 sporadic lung carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene were inactivated. All four tumors showed the presence of a MEN1 gene mutation and loss of the other allele. Observed mutations included a 1 bp insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide substitution affecting a donor splice site. Each mutation predicts truncation or potentially complete loss of menin. The remaining seven tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH. The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a complex germline MEN1 gene mutation. The data implicate the MEN1 gene in the pathogenesis of sporadic lung carcinoids, representing the first defined genetic alteration in these tumors.      

Variability in fecal water genotoxicity, determined using the Comet assay, is independent of endogenous N-nitroso compound formation attributed to red meat consumption

Red meat consumption causes a dose-dependent increase in fecal apparent total N-nitroso compounds (ATNC). The genotoxic effects of these ATNCs were investigated using two different Comet assay protocols to determine the genotoxicity of fecal water samples. Fecal water samples were obtained from two studies of a total of 21 individuals fed diets containing different amounts of red meat, protein, heme, and iron. The first protocol incubated the samples with HT-29 cells for 5 min at 4 degrees C, whereas the second protocol used a longer exposure time of 30 min and a higher incubation temperature of 37 degrees C. DNA strand breaks were quantified by the tail moment (DNA in the comet tail multiplied by the comet tail length). The results of the two Comet assay protocols were significantly correlated (r = 0.35, P = 0.003), however, only the second protocol resulted in detectable levels of DNA damage. Inter-individual effects were variable and there was no effect on fecal water genotoxicity by diet (P > 0.20), mean transit time (P = 0.588), or weight (P = 0.705). However, there was a highly significant effect of age (P = 0.019). There was no significant correlation between concentrations of ATNCs in fecal homogenates and fecal water genotoxicity (r = 0.04, P = 0.74). ATNC levels were lower in fecal water samples (272 microg/kg) compared to that of fecal homogenate samples (895 microg/kg) (P < 0.0001). Failure to find dietary effects on fecal water genotoxicity may therefore be attributed to individual variability and low levels of ATNCs in fecal water samples.     

De novo duplication of MECP2 in a girl with mental retardation and no obvious dysmorphic features

Makrythanasis P, Moix I, Gimelli S, Fluss J, Aliferis K, Antonarakis SE, Morris MA, Béna F, Bottani A. De novo duplication of MECP2 in a girl with mental retardation and no obvious dysmorphic features. Loss‐of‐function mutations of MECP2 are responsible for Rett syndrome (RTT), an X‐linked neurodevelopmental disorder affecting mainly girls. The availability of MECP2 testing has led to the identification of such mutations in girls with atypical RTT features and the recognition of milder forms. Furthermore, duplication of the entire gene has recently been described in boys with mental retardation and recurrent infections. We describe a girl with a heterozygous de novo MECP2 duplication. The patient, at the age of 19, has mental retardation with no autistic features. She is friendly but gets frequently anxious. She has neither dysmorphic features nor malformations. Her motor development was delayed with walking at 20 months. Speech is fluid with good pronunciation but is simple and repetitive. Diagnosis was made after single‐strand conformation analysis (SSCA) and multiplex ligation‐dependent probe amplification (MLPA) analysis of MECP2. Array comparative genomic hybridization (aCGH) analysis showed a duplication of 29 kb including MECP2 and part of IRAK1. Fluorescent in situ hybridization (FISH) has revealed that the duplicated region is inserted near the telomere of the short arm of chromosome 10. X‐chromosome inactivation in leukocyte DNA was not skewed. We conclude that it is likely that this MECP2 duplication is responsible for the mental retardation in this patient. This case broadens the phenotypic spectrum of MECP2 abnormalities with consequent implication in diagnosis and genetic counselling of girls with non‐syndromic mental retardation.