Global molecular epidemiology of the O15:K52:H1 extraintestinal pathogenic Escherichia coli clonal group: evidence of distribution beyond Europe

Escherichia coli O15:K52:H1 is a significant extraintestinal pathogen in Europe (G. Prats et al., J. Clin. Microbiol. 38:201-209, 2000). To search for evidence of this clonal group outside of Europe, 75 non-European E. coli isolates of serogroup O15 were compared with five members of the O15:K52:H1 clonal group from Barcelona, Spain, according to genomic background, virulence genotypes, and antimicrobial resistance profiles. Amplification phylotyping showed that 16 (21%) of the 75 non-European O15 isolates corresponded with the O15:K52:H1 clonal group. The 16 non-European O15:K52:H1 clonal group members represented diverse geographic locales. They were isolated almost exclusively from humans with extraintestinal infections and accounted for 50% of all O15 isolates from five human clinical collections studied. Most non-European clonal group members exhibited a consensus virulence factor profile that included the F16 or F7-2 papA alleles (P fimbrial structural subunit), papG allele II (P fimbrial adhesin), iha (putative adhesin siderophore), and iutA (aerobactin receptor). This resembles the virulence profiles of (i) European representatives of the O15:K52:H1 clonal group and (ii) phylogenetically related "clonal group A," a recently recognized significant contributor to trimethoprim-sulfamethoxazole resistance in the United States (A. R. Manges et al., N. Engl. J. Med. 345:1007-1013, 2001). Antimicrobial resistance profiles were variable, and resistance was inconsistently transferred by conjugation. These findings indicate that the O15:K52:H1 clonal group is broadly distributed beyond Europe, exhibits previously unrecognized phenotypic and genotypic diversity, and contributes significantly to extraintestinal infections in humans.     

The effects of co-culture with human fibroblasts on human embryo development in vitro and implantation

In a human in-vitro fertilization (IVF) programme, the effect of co- culture of embryos with human fibroblasts was evaluated with respect to pregnancy rate and embryo development. Patients were included in the study after giving informed written consent. The IVF treatments were randomly assigned by stratification of both age (<36 versus > or =36 years) and previous IVF attempts (yes versus no). After fertilization was established, the zygotes were transferred to a 4-well dish with or without fibroblasts and cultured for 2 days. On the third day after ovum pick-up (OPU), cell number and quality [5 (good) to 1 (poor)] of the embryos were scored and a maximum of three embryos was transferred. Supernumerary embryos of good quality were cryopreserved. The design of this study was a group sequential trial with the objective of detecting differences between pregnancy rates following IVF with conventional incubation or incubation in co-culture with fibroblasts. This design included one evaluation at half-way data collection. In the study, 148 patients had an OPU, of whom 77 were allocated to the co-culture group. There was no statistically significant difference in pregnancy rate, cell number and embryo quality between the two groups. The ongoing pregnancy rate per embryo transfer was 27% in co-culture and 30% in the conventional culture group. The implantation rates per transferred embryo were 17 and 18% respectively. Using a multivariate logistic regression model for the probability of ongoing pregnancies, the odds ratio of co-culture, adjusted for age and previous IVF attempts, was not statistically significant. In conclusion, co-culture with human fibroblasts does not contribute to an improvement of embryo quality nor to a higher pregnancy rate after IVF in an unselected group of patients.      

The right to an heir in the era of assisted reproduction

The latest remarkable technological advances in assisted reproduction, which enable cryopreservation of spermatozoa, embryos and ovarian tissue, raise difficult and debatable legal, social, ethical and moral issues concerning the right to posthumous reproduction. Furthermore, reports on the attitudes of the general public and of centres licensed for infertility treatment in the United Kingdom found that the majority of women and centres support the idea of posthumous reproduction. In this paper we review the data published on this issue, and after considering the various aspects, we conclude that each case should be discussed and authorized by a multidisciplinary committee that includes physicians, clergy, psychiatrists, psychologists, sociologists and other appropriate parties. In our opinion, the main principles that should guide this committee would allow posthumous reproduction in the context of marriage when a prior consent exists. For unmarried persons, post-mortem donation of gametes should be done only anonymously, if they are in agreement with existing laws concerning infertility treatments in every country and after appropriate consent and proper counselling. Moreover, any case which involves consanguinity or a possibility of incest should be forbidden, both for ethical and genetic reasons. In a case of pre-existing siblings, they should be consulted and their informed consent should be granted in advance so as to avoid legal problems in the inheritance of property.      

Blood supply of the olfactory nerve

Summary The authors report the results of a series of dissections and anatomic sections of the fronto-basal region of the brain and of the anterior cranial fossa in human cadavers. The constant presence of an arachnoidal cistern above the olfactory nerve was verified. The arachnoid separates from the pial membrane and forms a bridge with the ventral part of the olfactory bulb and tract, from the lateral edge of the olfactory sulcus to the medial edge of the gyrus rectus. The cistern is wide in its anterior portion, between the gyrus rectus and the olfactory bulb, and is reduced to a virtual slit in its posterior portion where the tract is lodged in the olfactory sulcus. The olfactory nerve can be separated without damaging fronto-basal arachnoidial adhesions over several centimeters. Dissection of this region after intravascular injection of colored media shows the constant presence of an artery destined to the olfactory bulb and tract. It originates either from the lateral surface of the anterior cerebral a. (segment A2), or from the medial fronto-basal a., and consistently provides terminal branches in front of the olfactory trigone in the medial olfactory sulcus. At their ventral extremity, the olfactory structures are therefore vascularised independently for several centimeters, from the lower face of the frontal lobe. The independent vascularisation of the olfactory nerve, the tenuous and easily detachable adhesions, and the actual presence of a true arachnoidal cistern all contribute to enabling surgical techniques which conserve olfactory function during anterior approaches.

---

Vascularisation du nerf olfactif. Rapports méningés et applications chirurgicales

Résumé Les auteurs rapportent les résultats d'une série de dissections et de coupes de la région fronto-basale de l'encéphale et de la fosse crânienne antérieure sur sujets cadavériques. La présence constante d'une citerne arachnoïdienne au dessus du n. olfactif a été vérifiée. L'arachnoïde se sépare du feuillet pial et passe en pont à la partie ventrale du bulbe et du tractus olfactifs, du bord latéral du sillon olfactif au bord médial du gyrus rectus. La citerne est large dans sa portion antérieure, entre le gyrus rectus et le bulbe olfactif, se réduit à une fente virtuelle postérieure lorsque le tractus se loge dans le sillon olfactif. Le n. olfactif peut être séparé sans dommage des adhérences arachnoïdiennes fronto-basales sur quelques centimètres. La dissection de cette région, après injection intravasculaire de masses colorées montre, de façon originale, la présence constante d'une artère destinée au tractus et au bulbe olfactifs. Elle naît soit de la face latérale de l'a. cérébrale antérieure (segment A2), soit de l'a. fronto-basale médiale, pour donner ses branches terminales toujours en avant du trigone olfactif dans le sillon orbitaire médial. Sur quelques centimètres à leur extrémité ventrale, les structures olfactives ont donc une vascularisation indépendante de la face inférieure du lobe frontal. L'indépendance vasculaire du n. olfactif, des adhérences ténues, facilement détachables, et la réalité vérifiée d'une véritable citerne arachnoïdienne permettent d'imaginer des techniques conservatrices de la fonction olfactive utilisées dans plusieurs indications de la chirurgie de la fosse crânienne antérieure.

     

<Emphasis Type="Italic">TCF7L2</Emphasis>variant genotypes and type 2 diabetes risk in Brazil: significant association,but not a significant tool for risk stratification in the general population

Background  

Genetic polymorphisms of the TCF7L2 gene are strongly associated with large increments in type 2 diabetes risk in different populations worldwide. In this study, we aimed to confirm the effect of the TCF7L2 polymorphism rs7903146 on diabetes risk in a Brazilian population and to assess the use of this genetic marker in improving diabetes risk prediction in the general population.     

Critical stages of tumor growth regulation in transgenic mice harboring a hepatocellular carcinoma revealed by distinct patterns of tumor necrosis factor-alpha and transforming growth factor-beta mRNA production

There is now good evidence that cytokines contribute to the regulation of tumor growth. The cytokine-driven modulation of tumor growth was investigated during the progression of a hepatocellular carcinoma (HCC) in SV40 large T tumor antigen transgenic mice. In vivo, an increased rate of liver growth correlated with increased transforming growth factor (TGF)-beta 1 mRNA expression, while the greatest amounts of tumor necrosis factor (TNF)-alpha mRNA were detected earlier during tumor development. Conversely, no particular alteration of IL-1 alpha, IL-1 beta, IL-6, IL-2, IL-4 and IFN-gamma mRNA production could be reported. In vitro, hepatocyte-like tumor cell lines established at two stages, either before or after HCC differentiation, were characterized. The early-stage-derived cell line produced TNF-alpha mRNA, but had barely detectable expression of TGF-beta 1 mRNA, while later-stage- derived cell lines showed the reciprocal pattern. All cell lines displayed a lack of sensitivity to TNF-alpha, although some degree of sensitivity to TNF-alpha could be observed in the presence of actinomycin-D or after treatment with IFN-gamma. The early-stage- derived cell line was sensitive to the growth inhibitory effects of TGF- beta 1, but late-stage-derived tumor cell lines displayed a loss of sensitivity to TGF-beta 1 which correlated with the increased expression of TGF-beta 1 mRNA. Altogether, this suggests that tumor cells contribute to the discrete TNF-alpha and TGF-beta 1 expression patterns during HCC progression. This model of HCC could be of valuable interest to assess the impact of various immunotherapeutic strategies on modulation of tumor growth.