Pax-1 in the development of the cervico-occipital transitional zone

The Pax-1 gene has been found to play an important role in the development of the vertebral column. The cervico-occipital transitional zone is a specialized region of the vertebral column, and malformations of this region have frequently been described in humans. The exact embryonic border between head and trunk is a matter of controversy. In order to determine a possible role of Pax-1 in the development of the cervico-occipital transitional zone we studied the expression of this gene in a series of quail embryos and murine fetuses with in situ hybridization and immunohistochemistry. Pax-1 is expressed in all somites of the embryo, including the first five occipital ones. During embryonic days 3–5 the gene is down-regulated in the caudal direction within the first five somites, whereas more caudally Pax-1 is strongly expressed in the cells of the perinotochordal tube. In 5-day-old quail embryos, the cartilaginous anlage of the basioccipital bone has developed and there is no more expression of Pax-1 in this region. The fusion of the dens axis with the body of the axis also coincides with switching off of the Pax-1 gene. More caudally, the gene is continuously expressed in the intervertebral discs of murine embryos and therefore seems to be important for the process of resegmentation. Quail embryos do not possess permanent intervertebral discs. Hyper- or hyposegmentation defects may be explained by an over- or under-expression of Pax-1 during development. We also reinvestigated the border between the head and trunk in chick embryos by performing homotopical grafting experiments of the 5^th somite between chick and quail embryos. Grafted quail cells formed mainly the caudal end of the basioccipital bone. They were also located in the cranial half of the ventral atlantic arch, and only a few cells were found in the tip of the dens axis.     

Interactions between smokers and non-smokers in public places: a qualitative study

Few studies have employed a qualitative approach to better understand how both smokers and non-smokers experience and make sense of no-smoking restrictions in their daily lives. We describe qualitative research involving an examination of self-reported interpersonal interactions between smokers and non-smokers in public places regarding exposure to environmental tobacco smoke (ETS). Five focus group discussions and twenty individual in-depth interviews were conducted with smokers and non-smokers in the Metropolitan Toronto region as a complement to a quantitative survey of the adult population of Ontario. Strategies used by non-smokers in responding to ETS exposures included verbal confrontations, non-verbal cues, use of a third party, and moving away. The perceived consequences of such actions, as described by both smokers and non-smokers, are discussed, together with implications for tobacco control policy and practice.     

Mutational specificity of aflatoxin B1. Comparison of in vivo host-mediated assay with in vitro S9 metabolic activation

An intrasanguineous host-mediated assay was used to determinethe pattern of mutagenesis induced by the carcinogen aflatoxinBl in the lacl gene of Escherichia coli recovered from rat liver.To investigate the influence of different types of metabolicactivation, the mutation spectrum induced by AFB1 activatedin vitro by a commercially prepared S9 microsomal fraction fromAroclor 1254-treated rats was also obtained. A total of 281forward mutations affecting the N-terminal region of the laclgene were characterized by DNA sequencing analysis. AFB1 inducedsimilar type of mutations with similar site specificity whenactivated by the standard S9 fraction or by employing a rathost-mediated assay. These results indicate the ability of thein vitro S9 fraction to mimic the in vivo metabolism, suggestingthat the same active metabolite, presumably AFB1 8, 9-epoxide,is responsible for generating a similar pattern of DNA damage,as reflected in the similarity of mutational spectra. For bothactivation systems, most mutations (>90%) were base substitutionsthat occurred primarily at G: C pairs. Somewhat over one-halfof G: C targeted substitutions were GC>TA transversions,other mutations being evenly divided between G: C>AT transitionsand GC>CG trans-versions. The mutational specificity exhibitedby activated AFB1 can be explained by incorporation of differentbases opposite a single type of non-instructive lesion duringerror-prone DNA synthesis. To what extent the mutations aredue to the main adduct (AFB1-N7-Gua), its imidazole-ring-openedderivative or an apurinic site remains unknown.     

Clinical and laboratory evaluation of the Shiley S-100-A oxygenator-heat exchanger

A new oxygenator the Shiley S-100-A has been evaluated. It incorporates a heat exchanger based on an anodised aluminium tube which replaces the polyurethane coated tube of the previous S-100 model. Data from 46 patients perfused with the Shiley S-100-A were reviewed and compared with figures derived from a previous group of 225 patients in whom the S-100 model was used. The gas transfer capacity of the S-100-A model is very good and comparable to that of the S-100 oxygenator at a low gas flow/blood flow ratio. However both "in vitro" and "in vivo" studies confirmed the superiority of the heat exchange capacity of the S-100-A model. The times required for cooling (from 36.5 to 29.6 degrees C) and rewarming (from 29.6 to 37 degrees C) for an adult patient of average build were 9.1 and 26 minutes for the S-100 model and 6.7 and 15 minutes for the S-100-A model respectively. In a separate group of patients cooled to and rewarmed from 26 degrees C the cooling and rewarming times were 12.4 and 23 minutes respectively.     

Gallium scintigraphy in Hansen's disease

Gallium 67 imaging was used in 12 patients with documented Hansen's disease undergoing treatment or not, in an attempt to determine the pattern of the disease. Diagnosis was confirmed by histopathology in all patients. The Mitsuda reaction was seen in all patients. Specific nuclear studies were performed when needed to evaluate particular organs better. Gallium 67 images show homogeneous, diffuse and moderate accumulation over the entire skin surface (except for the face) of untreated patients with multibacillary disease. The facial skin in these cases presented homogeneous, diffuse but very marked uptake of gallium. Internal organ involvement was variable. There was a very good correlation among clinical, scintigraphic, immunological and histopathological data. The pattern of the body skin (skin outlining) and facial skin (beard distribution) may be distinct for untreated patients with multibacillary leprosy.     

Seroreactivity to human papillomavirus (HPV) types 16, 18, or 31 and risk of subsequent HPV infection: results from a population-based study in Costa Rica.

Whether antibodies to human papillomavirus (HPV) capsids, elicited by natural infection, are protective is unknown. This question was addressed in a population-based cohort of 7046 women in Costa Rica by examining the association between baseline seroreactivity to HPV-16, HPV-18, or HPV-31 virus-like particles and the risk of subsequent HPV infection at a follow-up visit 5-7 years after enrollment. Seropositivity to HPV-16, HPV-18, or HPV-31 was not associated with a statistically significant decreased risk of infection with the homologous HPV type [relative risk (RR) and [95% confidence interval (CI)], 0.74 (0.45-1.2), 1.5 (0.83-2.7), and 0.94 (0.48-1.8), respectively]. Seropositivity to HPV-16 or HPV-31 was not associated with a decreased risk of infection with HPV-16 or its genetically related types [RR (95% CI), 0.82 (0.61-1.1) and 0.93 (0.68-1.2), respectively]. Seropositivity to HPV-18 was not associated with a decreased risk of infection with HPV-18 or its genetically related types (RR 1.3; 95% CI 1.0-1.8). Thus, we did not observe immunity, although a protective effect from natural infection cannot be excluded because of the limits of available assays and study designs.     

Predictors of cervical coinfection with multiple human papillomavirus types.

Women infected with multiple human papillomavirus (HPV) types seem to be at higher risk of cervical intraepithelial neoplasia, although there is controversy about whether coinfections are associated with lower or higher grades of dysplasia. There is no established risk factor profile for infection with multiple HPV types. We analyzed data from a prospective cohort of 2,075 Brazilian women to identify determinants of HPV coinfection. Cervical specimens were collected for cytology and HPV DNA detection. Data on baseline and time-dependent putative risk factors were obtained by interview. Baseline predictors of HPV coinfection included younger age, greater number of recent sexual partners, a history of condyloma but not of other sexually transmitted diseases, and younger age at first sexual intercourse. In repeated measures analyses, there was a weak positive association between the number of sexual partners in the time interval between two study visits and the risk of coinfection. Our results suggest that the risk factor profile for HPV coinfection among HPV-infected women shares several similarities with risk factors for any HPV infection.     

Tissue factor expression correlates with tumor angiogenesis and invasiveness in human hepatocellular carcinoma.

PURPOSE: Recent studies have shown that tissue factor (TF) may be involved in tumor angiogenesis and metastasis. The role of TF in hepatocellular carcinoma (HCC) was unknown. This study evaluated whether TF expression correlates with microvessel density (MVD), vascular endothelial growth factor (VEGF) expression, tumor invasiveness, and prognosis in human HCC. EXPERIMENTAL DESIGN: Tissue samples were obtained from 58 specimens of resected HCC. Immunohistochemical expression of TF was examined, and tumor MVD was evaluated using CD34 as the endothelial marker. TF and VEGF protein levels in the tumor cytosol were quantified by ELISA. Clinicopathologic and follow-up data of patients were prospectively collected. RESULTS: The immunohistochemical expression of TF in the tumors correlated significantly with tumor MVD (P = 0.002). The median cytosolic TF protein level in the tumors was 720 pg/mg total protein (range, 67-2406 pg/mg total protein). A significant positive correlation was found between TF and VEGF levels in the tumor cytosol (r = 0.475, P < 0.001). High tumor cytosolic TF level was associated with venous invasion (P = 0.004), microsatellite nodules (P = 0.024), unencapsulated tumor (P = 0.007), and advanced tumor stage (P = 0.010). A higher than median tumor cytosolic TF level was an independent predictor of poor survival (risk ratio, 1.836; 95% confidence interval 1.130-5.312, P = 0.023). CONCLUSIONS: This study shows that TF is related to tumor angiogenesis and invasiveness in HCC. Evaluation of tumor TF expression may be useful as a prognostic indicator in patients with HCC.     

Knowledge of reproduction in teenagers and young adults in Sweden.

OBJECTIVE: To investigate the knowledge of reproductive physiology and anatomy among adolescents and young adults in Sweden, and to evaluate the education obtained on these issues. METHODS: Two hundred and nine study specific questionnaires were distributed, of which 206 were answered by students in primary school, upper secondary school and at first year of university. A total knowledge score based on 21 out of the 35 questions in the questionnaire was calculated. As only 44 of the 206 respondents answered all the questions a revised score was also calculated, in which partial dropouts were interpreted as wrong answers. RESULTS: The mean of the total knowledge score was 28.7 out of 54 among the 44 respondents answering all questions, and the revised knowledge score was 24.0. The level of knowledge tended to be higher in older age groups, among women, as well as among respondents who had visited a Youth clinic. The time of ovulation was known by 21.4% of men compared to 63.4% of women. Almost 50% of the students knew one mechanism whereby oral contraceptives act to protect against pregnancy. Of the respondents, 77.2% knew of Chlamydia trachomatis but the knowledge of other STIs, like condyloma, was poorer (16.5%). Reasons for infertility were relatively well known among the respondents. Of the respondents, 57.5% stated that they had not received enough information on reproductive issues. CONCLUSIONS: The students have not achieved sufficient knowledge concerning sexual and reproductive matters that they, according to the national curriculum, should have attained by the end of the 9th grade. An improvement of the quality of the education, adapted to the students' age and pre-existing knowledge, and a review of the contents of the education is therefore needed.