Human malignant mesothelial cells: Variability of ultrastructural features in established and nude mice transplanted cell lines

The aim of this study was to determine, by transmission electron microscopy, the differentiation features of 21 human malignant mesothelioma cell lines (HMCLs) established from 13 specimens of 12 confirmed human malignant mesotheliomas, and of tumours induced in nude mice injected with 16 HMCLs. Fifty per cent of HMCLs showed typical mesothelial differentiation (long and slender microvilli, desmosomes, perinuclear intermediate filaments); 29 per cent did not show differentiation; and the remainder were poorly differentiated. Three human tumour specimens gave several different HMCLs; the cell lines obtained from a given tumour exhibited variable mesothelial differentiation. Eleven HMCLs were compared with the native tumour. Four were similar to the tumour and seven were less well differentiated, in most cases in relation to their microvilli. With six HMCLs, tumours induced in nude mice were less well differentiated than the corresponding cell lines, whereas with four HMCLs, tumours were equally or better differentiated. However, in most nude mice tumours, typical mesothelial microvilli were present. These results show that cell lines established from malignant mesothelioma may exhibit dedifferentiated features. However, while the variability in ultrastructural differentiation may result from the culture microenvironment, it could also be related to the state of differentiation, of the native tumour sample and to tumour cell heterogeneity.     

Electronic implementation of guidelines in the EsPeR system: a knowledge specification method

Despite initiatives to standardize methods for the development of clinical guidelines, several barriers hinder their integration in daily clinical practice: failure to fulfil quality criteria, poor effectiveness of their dissemination. Computerization of guidelines can favor their dissemination. The initial step of computerization is the knowledge specification from the text of the guideline. We describe the method of knowledge specification, which is used in EsPeR (Personalized Estimate of Risks), a web-based decision support system in preventive medicine, which allows, for a given person, to estimate risks and access recommendations, based on clinical profile. This method is based on a structured and systematic analysis of text allowing detailed specification of a decision tree. We use decision tables to validate the decision algorithm and decision trees to specify this algorithm, along with elementary messages of recommendation. Editing tools are used to facilitate the process of validation and the workflow between expert physicians and computer scientists. Applied to eleven different guidelines, the method allows a quick and valid computerization and integration in the EsPeR system. The method used for computerization could help to define a framework usable at the initial step of guideline development in order to produce guidelines ready for electronic implementation.     

Factors involved in the sensitivity of different hematopoietic cell lines to infection by subgroup C adenovirus: implication for gene therapy of human lymphocytic malignancies

Gene transfer approaches using viruses such human adenovirus (HAdV) may provide an alternative treatment for diseases involving hematopoietic cells. Better understanding of the cellular mechanisms by which the HAdV introduces DNA into these cells should help in vector design. We examined HAdV intracellular delivery in several cell lines including B and T lymphocytes. We demonstrated that HAdV resistance in most B lymphocytes is the result of moderate HAdV uptake. In contrast, high levels of coxsackie and HAdV receptor (hCAR) are expressed on the surface of HSB2 (T cells), allowing efficient binding and uptake but no transgene expression, probably because of deficient endosomolysis and subsequent exocytose. This work demonstrates the existence of hCAR-dependent and -independent endocytic route in hematopoietic cells. Moreover, it precises the intracellular barriers to be overcome by HAdV in such cells to be infectious and gives previous information's to design new vectors for gene transfer.     

Origin and filiation of human plasmacytoid dendritic cells

Human plasmacytoid dendritic cells represent a rare population of leukocytes which produce high amounts of type I interferon in response to certain viruses. Although those cells were first described in 1958, there are still unsolved issues related to their origin and function. Recently, a leukemic counterpart of plasmacytoid dendritic cells was identified. Molecular approaches using either normal or leukemic plasmacytoid dendritic cells provide some new insights into the controversial lymphoid origin of those cells. The need for specific markers is still a critical aspect for the identification of plasmacytoid dendritic cells, whatever stage of differentiation, in normal as well as in pathological conditions. Hopefully, novel markers will allow delineation of the relationships between dendritic cells at different stages of differentiation/maturation along the myeloid and lymphoid lineages.     

Immune status and uptake of antiretroviral interventions to prevent mother-to-child transmission of HIV-1 in Africa

The aim of this study performed in Abidjan, C?te d'Ivoire, was to describe the distribution of CD4+ T-cell lymphocytes (CD4) in HIV-1-infected (HIV+) pregnant women diagnosed during prenatal voluntary counseling and testing and to assess whether HIV-related immunodeficiency influenced the acceptance of an antiretroviral (ARV) package (zidovudine beginning at 36 weeks of amenorrhea plus intrapartum nevirapine) to prevent mother-to-child transmission. Between April and June 2002, a CD4 count was systematically performed in all HIV+ women (n=221) in 5 antenatal clinics carrying out voluntary counseling and testing. No difference in CD4 count was found in HIV+ women who did not return for their test result (n=50) and those who were informed of their positive serostatus (n=171) (median CD4 count: 389/mm3 vs. 420/mm3; P=0.19). We also found a lack of difference in CD4 count in those who accepted ARV (n=72) and those who did not but knew their HIV status (n=99) (median CD4 count: 405/mm3 vs. 425/mm3; P=0.47). The overall uptake of the intervention (31.9%) appeared to be independent of the maternal immune status.     

Causal pathways of the effects of age and the CCR5-Delta32, CCR2-64I, and SDF-1 3'A alleles on AIDS development

OBJECTIVE: To investigate the causal pathways by which age and the CCR5-Delta32, CCR2-64I, and SDF-1 3'A alleles influence progression to AIDS. DESIGN: Analysis of follow-up data from 2 cohort studies among homosexual men (n=400), having >10 years of follow-up. METHODS: The effects of the 4 cofactors on the CD4 and HIV-1 RNA trajectories after seroconversion were modeled in a random-effects model. A proportional hazards model was used to investigate their effect on the risk of AIDS after correction for CD4 cell count and RNA level. This approach allows investigation as to whether they influence AIDS progression by affecting CD4 count and RNA level or by other pathways. RESULTS: Persons of younger age or having the CCR2-64I or SDF-1 3'A mutation have significantly higher CD4 levels. Persons with the CCR5-Delta32 deletion or CCR2-64I mutation have significantly lower RNA levels. After correction for both CD4 count and RNA level, only the SDF-1 3'A mutation significantly increases the AIDS risk. CONCLUSIONS: Age and the CCR5-Delta32 deletion and CCR2-64I mutation influence AIDS progression by affecting CD4 and HIV-1 RNA. The SDF-1 3'A allele increases the AIDS risk, but this effect is countered by its effect on CD4 and HIV-1 RNA level.     

Clinical and molecular overlap in overgrowth syndromes

Here, we report the clinical and molecular analysis of 75 patients with overgrowth and mental retardation, including 45 previously reported cases [Rio et al., 2003; Baujat et al., 2004]. Two groups are distinguished: group I corresponding to patients with recognizable overgrowth syndromes (Sotos syndrome (SS), Weaver syndrome (WS), Beckwith-Wiedemann syndrome, Simpson-Golabi-Behmel syndrome (SGBS), and del(22)(qter) syndrome) (60 cases) and group II corresponding to unclassified cases (15 patients). We investigated NSD1 and GPC3 deletions or mutations, 11p15 abnormalities, and 22qter deletions. Surprisingly, in Group I, two SS patients had 11p15 abnormalities and two patients with Beckwith-Wiedemann syndrome had NSD1 aberrations. In group II, two cases of del(22)(qter) were identified but neither NSD1, 11p15, nor GPC3 abnormalities were detected. These results emphasize the clinical and molecular overlap in overgrowth conditions.     

Genetic counseling dilemmas: Down syndrome,paternal age,and recurrence risk after remarriage

The recent demonstration that about 20–30% of cases of Down syndrome are of paternal origin has again raised interest in the question of the possible contribution of paternal age independent of maternal age to a couple's risk of a Down syndrome live birth. In this paper the nature of the available evidence is critically reviewed, interpretations reconciling differences between studies that reached opposite conclusions are presented, and an approach to genetic counseling in the face of such apparent differences in the literature is discussed. It is not likely that data from ad hoc studies of parental origin of the extra chromosome will be sufficient to judge the existence or magnitude of paternal age-specific risk, and reliance must be made on statistical studies that searched for paternal age effects while controlling for maternal age. The literature is consistent with an apparent doubling of risk for paternal age 55 and over, but no effect at younger paternal ages. With regard to remarriage, it is suggested that if members of a couple with a 47, +21 child remarry it be assumed that the excess risk “travels” to that new couple which includes the parent in whom non-disjunction occurred in the previous marriage. If parental origin is not known, it is suggested that the risk be calculated on the assumption of a 20–30% likelihood that it was of paternal origin and a 70–80% likelihood that it was of maternal origin, and that the excess empiric risks be apportioned accordingly in the new marriages.     

Virilism as a late manifestation in the Bardet-Biedl syndrome

The second case of virilism as a late manifestation of Bardet-Biedl syndrome (BBS) is described, with endocrine and histological evaluation. Both cases manifested ovulatory cycles and developed virilism in adulthood. Elevated plasma testosterone and 17-OH-progesterone were not suppressed by dexamethasone but were suppressed by medroxyprogesterone acetate. Peripheral and ovarian venous blood obtained at the time of surgery demonstrated a marked gradient for testosterone in both ovaries and for progesterone in the ovary bearing the corpus luteum. Histological evaluation of the ovaries demonstrated bilateral ovarian stromal hyperplasia with focal hyperthecosis. Bilateral ovariectomy resulted in complete correction of the endocrine abnormality, although the established hirsutism remains a mark of previous androgen excess.