Studies of porcine reproductive and respiratory syndrome (PRRS) virus infection in avian species

Porcine reproductive and respiratory syndrome virus (PRRSV) is a recently recognized virus of swine. As a newly emerging virus, much of the basic information regarding PRRSV is in the process of discovery. We report three experiments with PRRSV in birds, and a fourth experiment to evaluate the infectivity and transmissibility of avian-derived PRRSV in swine. Experiment 1 compared the susceptibility of Muscovy ducks, Mallard ducks, guinea fowl, and chickens to PRRSV. Birds were exposed to PRRSV (ATCC VR-2402) in drinking water and virus isolation was attempted from feces collected from cages. Based on the duration of fecal shedding of the virus, this experiment showed that Mallard ducks were particularly susceptible to PRRSV. Experiment 2 was done in mallards to corroborate and augment the observations of experiment 1. Virus was isolated from pooled mallard feces up to 25 days post exposure (PE) and from the intestinal contents of 8 of 20 birds euthanized on day 38 PE. No gross or microscopic lesions were observed in ducks collected between 0 and 15 days PE. Experiment 3 evaluated the infectivity and transmissibility of mallard-derived PRRSV in mallards. A cage of mallards orally exposed to PRRSV shed the virus in feces. Exposure of a second cage of mallards to feces from the first cage resulted in fecal shedding of PRRSV by birds in cage two. In turn, exposure to feces from the second cage led to fecal shedding by mallards in a third cage. Experiment 4 assessed the infectivity and transmissibility of mallard-derived virus in swine. Pigs intranasally exposed to PRRSV isolaed from mallard feces in experiment 2 became viremic, seroconverted by ELISA, and transmitted the virus to sentinel swine. Collectively, these studies show that the possibility exists for avian species to be involved in the epidemiology of PRRSV. This is the first report of PRRSV infection in a species other than swine.     

Molecular analysis of Shiga toxigenic Escherichia coli O111:H- proteins which react with sera from patients with hemolytic-uremic syndrome

Western blot analysis was used to assess the reactivity of convalescent-phase sera from patients who were associated with an outbreak of hemolytic-uremic syndrome (HUS) caused by fermented sausage contaminated with Shiga toxin-producing Escherichia coli (STEC). The predominant STEC isolated from HUS patients belonged to serotype O111:H-, and reactivity to O111:H- whole-cell lysates, treated or untreated with proteinase K, was examined. As expected, all five serum samples demonstrated a marked anti-lipopolysaccharide response, but several protein bands were also immunoreactive, particularly one with an apparent size of 94 kDa. One convalescent-phase serum sample was subsequently used to screen an O111:H- cosmid bank and 2 of 900 cosmid clones were found to be positive, both of which contained a similar DNA insert. Western blot analysis of one of these clones identified three major immunoreactive protein bands of approximately 94, 70, and 50 kDa. An immune response to the three proteins was detectable with all five convalescent-phase serum samples but not with healthy human serum. Immunoreactive 94- and 50-kDa species were produced by a deletion derivative of the cosmid containing a 7-kb STEC DNA insert. Sequence analysis of this region indicated that it is part of the locus for enterocyte effacement, including the eaeA gene which encodes intimin. The deduced amino acid sequence of the O111:H- intimin was 88.6% identical to intimin from O157:H7 STEC, and the most divergent region was the 200 residues at the carboxyl terminus, which were only 75% identical. Such variation may be antigenically significant as serum from a HUS patient infected only with the O111:H- STEC reacted with intimin from an enteropathogenic E. coli O111 strain, as well as several other eaeA-positive STEC isolates, but not with an eaeA-positive STEC belonging to serotype O157:H-. Sera from two of the other HUS patients also failed to react with intimin from this latter strain. However, intimin from O157:H- STEC did react with serum from a patient infected with both O111:H- and O157:H- STEC.     

E2A deficiency leads to abnormalities in alphabeta T-cell development and to rapid development of T-cell lymphomas

The E2A gene products, E12 and E47, are critical for proper early B-cell development and commitment to the B-cell lineage. Here we reveal a new role for E2A in T-lymphocyte development. Loss of E2A activity results in a partial block at the earliest stage of T-lineage development. This early T-cell phenotype precedes the development of a T-cell lymphoma which occurs between 3 and 9 months of age. The thymomas are monoclonal and highly malignant and display a cell surface phenotype similar to that of immature thymocytes. In addition, the thymomas generally express high levels of c-myc. As assayed by comparative genomic hybridization, each of the tumor populations analyzed showed a nonrandom gain of chromosome 15, which contains the c-myc gene. Taken together, the data suggest that the E2A gene products play a role early in thymocyte development that is similar to their function in B-lineage determination. Furthermore, the lack of E2A results in development of T-cell malignancies, and we propose that E2A inactivation is a common feature of a wide variety of human T-cell proliferative disorders, including those involving the E2A heterodimeric partners tal-1 and lyl-1.     

Molecular analysis of the Drosophila catalase gene

OBJECTIVE: To determine whether genetic and non-genetic components of interindividual variation in systolic and diastolic blood pressure are constant throughout the day or are time or activity dependent. METHODS: We obtained 24 h ambulatory blood pressure recordings in 263 members of 68 unrelated nuclear families (i.e. parents and their offspring) representative of the Caucasian population of Rochester, MN, USA. Using the time each patient got into bed as a reference point, we identified 198 records in which this reference point was preceded by eight consecutive active hours (out of bed) and followed by four consecutive inactive hours (in bed) in which four or more blood pressure readings taken each hour were judged to be technically satisfactory. For each hourly mean for systolic and diastolic blood pressure, we estimated total interindividual variance, variance associated with concomitant variables (generation; sex within generation strata; and age, height, weight, body mass index, and abdomen-to-hip ratio within generation and sex strata), and variance associated with additive genetic effects (i.e. the chief cause of resemblance between relatives). To assess trends in each component of interindividual blood pressure variance over the 12 h period, we estimated the slope of the linear regression line fit to the hourly estimates. RESULTS: For systolic blood pressure, total interindividual variance did not change significantly (slope of regression line = -0.23, P = 0.717). In contrast, total interindividual variance for diastolic blood pressure was greater during active hours than inactive hours (slope of regression line = -5.53, P < 0.001). For both systolic and diastolic blood pressure, variance associated with the concomitant variables was greater during active hours than during inactive hours (for systolic blood pressure slope of regression line = -2.98, P = 0.001; for diastolic blood pressure slope of regression line = -6.14, P < 0.001). Likewise, for both systolic and diastolic blood pressure, variance associated with additive genetic effects was also greater during active hours than during inactive hours (for systolic blood pressure slope of regression line = -1.65, P = 0.090; for diastolic blood pressure slope of regression line = -1.47, P = 0.018). CONCLUSIONS: This study demonstrates that components of interindividual variation in blood pressure are not constant, but are time or activity dependent.     

Personality disorders and treatment outcome in methadone maintenance patients

This study examined the relationship between personality disorder (PDs) and 7-month treatment outcome in 197 men admitted to methadone maintenance. Subjects reported pervasive improvement, and the amount of improvement did not significantly differ for those subjects with and without PDs. PD subjects entered treatment with more severe self-reported drug, alcohol, psychiatric, and legal problems, and despite progress, remained more problematic in those areas relative to subjects without PDs. Subjects with antisocial PD had admission and 7-month problem status similar to subjects with other PDs. The 7-month urinalysis results for opiates and cocaine showed no significant differences between subjects with and without PDs. Fewer PD subjects stayed in treatment continuously for the 7-month period. Several cluster B PDs-borderline, antisocial, and histrionic-predicted poorest overall outcomes. Methadone-maintained patients with PDs may warrant additional treatment services if they are to approach the functional level of patients without PDs.     

Hypertension and its treatment in the NINDS rt-PA Stroke Trial

The effects of dietary oligosaccharides on the hepatotoxic action of D-galactosamine (GalN) were investigated in this study. Male Wistar rats fed with 20% casein diets containing 10% oligosaccharide or D-galactose (Gal) for 2 weeks were injected with GalN (1,900 mg/kg of body weight), and the plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities and the hepatic glycogen concentration were examined 20 hours after the injection. The plasma AST and ALT activities in experiment 1 for the Gal + neomycin (NEO) group were significantly lower than those for the control (C), NEO, raffinose (RAF) + NEO and galacto-oligosaccharide (GA-LO) + NEO groups. In experiment 2, these activities were significantly lower in the Gal, Gal + NEO and RAF groups than in the RAF + NEO group when the groups were treated with GalN. On the other hand, in respect of the hepatic glycogen concentration in experiment 1, that of the Gal + NEO group was higher than that of the C, NEO, RAF + NEO or GALO + NEO groups. In experiment 2, this parameter was significantly higher in the Gal, Gal + NEO and RAF groups than in the RAF + NEO group after the GalN treatment. As a result, it is suggested that the GalN-hepatitis-suppressive effects of indigestible oligosaccharides such as RAF or GALO is mediated by the action of intestinal bacteria.     

The impact of motivationally neutral cues on psychopathic individuals: assessing the generality of the response modulation hypothesis

Psychopathic individuals' lack of responsiveness to punishment cues and poor self-regulation have been attributed to fearlessness (D. T. Lykken, 1957, 1982, 1995). Alternatively, deficient response modulation (RM) may hinder the psychopathic individual's processing of peripheral information and self-regulation when they are engaged in goal-directed behavior (C. M. Patterson & J. P. Newman, 1993). Although more specific than the fearlessness hypothesis in some respects, the RM hypothesis makes the more general prediction that psychopathic individuals will have difficulty processing motivationally neutral as well as fear-related stimuli. The authors assessed this prediction by using psychopathic and nonpsychopathic male inmates subdivided by level of anxiety/negative affectivity (NA). As predicted by the RM hypothesis, peripheral presentation of motivationally neutral cues produced significantly less interference in low-NA psychopathic individuals than in low-NA controls.     

An explicit construction of a sequence of codes attaining theTsfasman-Vladut-Zink bound. The first steps

We present a sequence of codes attaining the Tsfasman-Vladut-Zink bound. The construction is based on the tower of Artin-Schreier extensions described by Garcia and Stichtenoth (1995). We also determine the dual codes. The first steps of the constructions are explicitly given as generator matrices