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PROBLEM ADDRESSED: Shiga toxin-producing Escherichia coli (STEC) are a group of bacteria responsible for food-associated diseases. Clinical features include a wide range of symptoms such as diarrhea, hemorrhagic colitis and the hemolytic uremic syndrome (HUS), a life-threatening condition. OBJECTIVE: Our group has observed that animals naturally colonized with STEC strains of unknown serotype were not efficiently colonized with E. coli O157:H7 after experimental infection. In order to assess the basis of the interference, three STEC strains were isolated from STEC persistently-colonized healthy cattle from a dairy farm in Buenos Aires, Argentina. METHODS AND RESULTS: The three isolated strains are E. coli O22:H8 and carry the stx1 and stx2d genes. The activatable activity of Stx2d was demonstrated in vitro. The three strains carry the adhesins iha, ehaA and lpfO113. E. coli O22:H8 formed stronger biofilms in abiotic surface than E. coli O157:H7 (eae+, stx2+) and displayed a more adherent phenotype in vitro towards HeLa cells. Furthermore, when both serotypes were cultured together O22:H8 could reduce O157:H7 adherence in vitro. When calves were intragastrically pre-challenged with 108 CFU of a mixture of the three STEC strains and two days later challenged with the same dose of the strain E. coli O157:H7 438/99, the shedding of the pathogen was significantly reduced. CONCLUSIONS: These results suggest that E. coli O22:H8, a serotype rarely associated with human illness, might compete with O157:H7 at the bovine recto-anal junction, making non-O157 carrying-calves less susceptible to O157:H7 colonization and shedding of the bacteria to the environment.

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Escherichia coli O157:H7 is the main causative agent of haemolytic uremic syndrome. Cattle are the main reservoir of these bacteria, and have been shown to develop immune response to colonization. Our aim was to investigate the faecal shedding pattern of E. coli O157:H7 in calves challenged intragastrically with either 10(8) or 10(10) CFU, as well as the ability of specific preexisting antibodies to reduce shedding of the pathogen. Shedding was analysed by direct counting as well as enrichment of rectoanal mucosal swabs. Statistical analysis was performed using a linear model for repeated measures with and without the inclusion of preexisting antibodies against the carboxy-terminal fraction of intimin-γ (γ-intimin C280) as a covariable. Results suggest that there is a statistical difference in the area under the shedding curves between both doses for 14 as well as 28 days after challenge (p = 0.0069 and 0.0209, resp.). This difference is increased when the prechallenge antibodies are taken into account (p = 0.0056 and 0.0185). We concluded that the bacterial dose influences shedding on calves experimentally challenged and that preexisting antibodies against E. coli O157:H7 γ-intimin C280 could partially reduce faecal excretion.

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El objetivo del presente trabajo fue determinar en cerebros postmortem, las correlaciones entre los valores de las superficies corticales de cada uno de los hemisferios del área anterior del lenguaje, el plano temporal, el plano ascendente posterior, el giro cingular anterior y sus respectivas asimetrías por ciento (ASIM por ciento). Se calcularon los coeficientes de correlación de Pearson y sus significaciones estadísticas. Los valores de asimetrías y de superficies corticales fueron determinados y publicados anteriormente (ALBANESE et al. 1989; 1995; 1997). Las correlaciones que se muestran en el presente trabajo no han sido publicadas. El área anterior del lenguaje (n=24) y el plano temporal (n=17) que presentan lateralidad izquierda, muestran correlaciones de signo positivo y estadísticamente significativas, entre las respectivas ASIM por ciento y las correspondientes superficies derechas. Sus coeficientes de correlación (r) y sus significaciones estadísticas son respectivamente 0,43 p<0,05 y 0,65 p<0,01. Dichas asimetrías no correlacionan significativamente con las correspondientes superficies izquierdas. El plano ascendente posterior (n=17) y el giro cingular anterior (n=20) que presentan lateralidad derecha muestran correlaciones de signo negativo y estadísticamente significativas entre las respectivas ASIM por ciento y sus correspondientes superficies izquierdas. Sus coeficientes de correlación (r) y sus significaciones estadísticas son respectivamente -0,50 p<0,05 y -0,72 p<0,01. Dichas asimetrías no se correlacionan significativamente con las correspondientes superficies derechas. Los resultados indican que en las cuatro zonas estudiadas, las respectivas asimetrías se correlacionan significativamente con la superficie correspondiente al hemisferio contralaleral al dominante. Esto sugiere su probable compromiso en el desarrollo de la asimetría. El hallazgo de estas y otras correlaciones entre valores obtenidos de estudios morfológicos cerebrales en sujetos controles, sugiere la existencia de patrones de orden aún poco explorados, los que podrían estar alterados en enfermos mentales

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Morphological brain alterations have long been noted in schizophrenia, although it is unclear whether they are a consequence of an early disturbance in brain development or represent a deterioration of a normal brain structure. The purpose of the present study is to establish a relationship between corpus callosum (CC) surface and perimeter. A female right handed schizophrenic group (n = 31) was compared with a control group (n = 25) of comparable sex, age (range: 40-68 years) and handedness on measures of the CC area from a midsagittal T1 weighted image magnetic resonance imaging. Patients completed DSM IV criteria for Residual Schizophrenia. Patients with a known history of brain injury or neurologic illness were excluded. All had received neuroleptic drugs but no electroconvulsive treatment. Control and schizophrenic groups were subdivided into two age-ranges (E1 < or = 54 years and E2 > 54 years). Mean +/- SE (cm2) of CC surface in controls E < or = 54 and E > 54 were respectively 7.09 +/- 0.42 and 8.97 +/- 0.62 (p < 0.01) and in schizophrenics E < or = 54 and E > 54 were respectively 7.61 +/- 0.24 and 6.60 +/- 0.29 (p < 0.05). Among control and schizophrenic E > 54 sub-groups there were significant differences (p < 0.01). Statistically significant differences among sub-group values were obtained through analysis of variance. Correlation coefficient (r) between age and surface in control and schizophrenic groups were respectively 0.55; p < 0.05 and -0.45; p < 0.02. Our results provide evidence that chronic female schizophrenic patients have diminished CC surface and altered proportionality among surface and perimeter, that increases with age. However, in the control group, there is an increment of corpus callosum surface without altered perimeter proportionality.

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The anterior cingulate gyrus (acg) is involved in mechanisms of attention and emotion, where the right hemisphere is considered to be dominant. One of the models for neuropsychological dysfunction in schizophrenia suggests an impairment in the balance of lateralized functions. Fourteen adult human female brains, having no macroscopic lesions, were used in this study. Seven brains came from female patients with clinical diagnoses of residual schizophrenia (DSM-III-R; APA 1987). Seven female brains were used as controls. Thirteen male brains were also studied, with the sole purpose of establishing the typicality of the female controls. All schizophrenic brains were age matched with control brains. Right laterality for weight (71.4%) and surface (85.7%) was observed in the acg of female control brains. The inversion of this laterality in a significant number of the schizophrenic cases was the most relevant finding in this study.

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Seventy-eight patients who had constitutional delay of growth and puberty were included in a retrospective study to determine whether, at the time of first evaluation, any predictive features could suggest final height outcome. Mean chronologic age was 14.3 years (range, 12 to 18 years), and all were either prepubertal or in an early stage of pubertal maturation (4 ml testicular volume). Initial mean (+/- SD) height standard deviation score was -2.74 (+/- 0.71); 85% had a relatively short spine compared with subischial leg length. Mean (+/- SD) growth rate was 4.8 (+/- 1.6) cm/year, and epiphyseal maturation was delayed by 2.4 (+/- 1) years. Sixteen boys were treated with a sustained-action preparation of testosterone (50 mg monthly for 3 to 4 months), six with oxandrolone (1.25 mg daily for a mean of 4 months), and one with both drugs in sequence. At final height attainment, 58% of the boys failed to achieve their full genetic potential; among the remaining 42%, only 0.7% attained a final height above corrected mid-parental height. The relative disproportion between the segments had no significant change at final height attainment. Regression analysis showed that final height impairment (the difference between mid-parental height and final height) was negatively influenced by standing height and growth velocity when initially evaluated and positively by the degree of segmental body proportion; that is, patients who were taller, were growing at a faster rate, and who had a major degree of segmental body disproportion with a short spine and long leg length attained a final height closer to their mid-parental height, irrespective of the degree of delayed epiphyseal maturation. Neither testosterone nor oxandrolone administered during early puberty modified final height attainment or segmental proportion. We conclude that a late onset in the timing of puberty seems to be deleterious to spinal growth and consequently to final height attainment. An alternative diagnosis should be sought among patients with features of constitutional delay of growth and puberty who do not have a significant degree of body disproportion. In these patients, as well as in those who are extremely short, who have a poor growth rate, or who have an unfavorable genetic potential, an alternative therapeutic approach may be required.

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Results of this work show, in the inferior frontal gyrus and in the different portions into which it was divided, asymmetry of weight and cortical surface and left predominance in the posterior portion, which is concerned with language. In spite of the difference among the absolute individual values, the correlation between weight and surface values is excellent in all cases, and the weight and surface ratio is the same for the portions related to language and different for the remainder of the inferior frontal gyrus.

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