[Celiac disease: special features in Africa. Description of 8 cases in Djibouti (horn of Africa)]. / Maladie coeliaque: particularités africaines. A propos de 8 cas à Djibouti.

Celiac disease is poorly documented in intertropical Africa. The purpose of this retrospective report was to describe 8 cases observed at the Groupement Medico-Chirurgical of Bouffard Hospital in Djibouti (Horn of Africa) between January 2003 and January 2006. There were 5 females and 3 males ranging in age from 9 months to 17 years old (mean age: 48 months). Six patients were of Somali ethnic origin and two of Yemenite ethnic origin. Six were classified as middle class and 2 as lower class. All forms were symptomatic associating constant loss of weight with digestive manifestations (diarrhoea and vomiting). Diagnosis of celiac disease was based on the presence of anti-gliadin antibodies IgA and IgG associated with anti-endomysium or anti-transglutaminase antibodies that were measured in six and two cases respectively. Gastroduodenal endoscopy performed in three cases including two with duodenal biopsy demonstrated villous atrophy associated with gross of intra-epithelial lymphocytosis. A gluten-free diet initiated in five patients led to clinical improvement in four cases with a follow-up of 8.25 months. The findings of this study in Djibouti show that celiac disease exists in intertropical Africa. Its presentation is quite similar to elsewhere but diagnosis is more difficult due to poor knowledge about the disease and limited diagnostic facilities. Favourable response to presumptive treatment by a gluten-free diet is an alternative for diagnosis especially in Djibouti where eating habits differ from those in industrialized countries and this type of diet is easier to follow.

[Extensive bone marrow necrosis as presenting manifestation of sickle cell disease in Africa]. / Necrose médullaire etendue en Afrique révélant une drépanocytose homozygote.

Extensive bone marrow necrosis is a rare but severe complication of sickle cell disease. A formerly healthy man was admitted for bone pain, fever, and jaundice with severe aregenerative anemia. Bone marrow aspiration and biopsy showed extensive bone marrow necrosis while hemoglobin electrophoresis demonstrated homozygotic sickle cell disease. Despite early onset of septic arthritis of the right shoulder, outcome after blood transfusion and nonspecific treatment was favorable. Six months later, hemoglobin level remained stable up to 97 g/L. This first African case report illustrates typical features and good prognosis of extensive bone marrow necrosis in sickle cell disease. Extensive bone marrow necrosis is a highly unusual presenting manifestation of sickle cell in an adult.

[Management of Grave's disease in the tropics (experience at Bouffard Army Hospital Center in Djibouti]. / Prise en charge de la maladie de Basedow en milieu tropical (expérience du cha Bouffard de Djibouti).

Based on their experience in managing Grave's disease at the Bouffard Army Hospital Center within the local health care context in Djibouti, the authors advocate surgery as the first line treatment. Medical and economical factors supporting this preference are discussed so that readers can adapt them to his own local context.

[Clinical overview of New World tegumentary leishmaniasis]. / Panorama clinique des leishmanioses tégumentaires du Nouveau Monde.

This richly illustrated article (80 color photographs) based on the authors' experience in French Guyana documents the clinical diversity of American tegumentary leishmaniasis. Main highlights include the often outstanding aspect of lesions, the high frequency of forms not associated with ulceration or scab formation that must be recognized to achieve diagnosis in travellers returning from endemic zones, and the special prognosis of clinical forms associated with intradermic, lymphatic or hematogenous spread. The article also reviews an original diagnostic method based on culture of cutaneous biopsy specimens on specific nutrient mediums that provides isolates in a high percentage of cases (80%) and thus allows identification of offending parasite.

[An uncommon cause of persistent fever in France]. / Une fièvre au long cours inhabituelle en France.

Miliary tuberculosis is rare and requires rapid diagnosis. Outcome is fatal in 25% of the cases. Since radiography and laboratory tests contribute little to early diagnosis, clinical findings are primordial. Antituberculosis antibiotic therapy is frequently started before microbiological confirmation of the diagnosis.

Identification of SV40 T-antigen mutants that alter T-antigen-induced chromosome damage in human fibroblasts.

The SV40 T antigen causes numerical (aneuploidy) and structural (aberrations) chromosome damage when expressed in human diploid fibroblasts. This chromosome damage precedes the acquisition of neoplastic traits such as anchorage independence, colony formation in reduced serum growth factors, immortalization, or tumorigenicity. Therefore, chromosome damage may be important in acquiring these traits because it could provide a mutational mechanism. To determine how the T antigen causes chromosome damage, point mutations were constructed that altered previously defined biochemical functions of the T protein. Mutant T antigen constructs were introduced into human diploid fibroblasts and selected by using G418. Clones of G418r cells that expressed mutant T antigens were expanded and scored for chromosome damage. Most of these mutant T antigens caused [corrected] levels of chromosome damage similar to those caused by [corrected] the wild-type T antigen. However, some T-antigen mutants induced fewer chromosome changes. A subset of these clones that induced less chromosome damage than wild-type T were examined further. Mutant T-antigen protein levels from this subset were quantified with flow cytometry and compared with wild-type protein expression levels. Mutations of T antigen shown previously to form less stable complexes with p53 caused less chromosome damage. A mutation in the zinc finger domain of T antigen also caused less chromosome damage. Interestingly, a mutant that caused loss of the ATPase activity of T antigen caused an increase in endoreduplicated cells. Also, a correlation was noted between cells expressing very low levels of T antigen (below detection limits when using flow cytometry) and an undamaged karyotype. This correlation indicates that there is a threshold level of T-antigen expression that induces chromosome damage and that expression levels on a per-cell basis rather than on a population basis should be considered in subsequent studies.

[Soft tissue eosinophilic granuloma or Kimura's disease: a case report]. / Le granulome eosinophile des tissues mous ou maladie de Kimura: a propos d'un cas.

Soft tissue eosinophilic granuloma or Kimura's disease is a chronic inflammatory disorder of unknown etiology. It is endemic in the Far East but can occur sporadically in other populations especially Middle Eastern peoples as illustrated by the present case involving a 55-year-old man. Examination 8 years after an initial episode revealed masses in the cheek and submaxillary regions with hypereosinophilia and characteristic histological findings. The usual clinical presentation of Kimura's disease includes subcutaneous nodules with lymph node involvement or presence of tumor in the salivary glands. These clinicopathological findings require differential diagnosis with Hodgkin's lymphoma, dermopathic lymphoma, or Castelman's disease. However, the most difficult distinction involves angiolymphoid hyperplasia with eosinophilia. Final diagnosis requires anatomopathological study. The most frequently encountered histological criteria are preservation of node structure, highly developed germinal centers, eosinophilic infiltration, and presence of numerous postcapillary veinlets. Prognosis is favorable but multiple relapses are possible. Corticosteroid therapy is usually effective but radiation treatment may be necessary in patients with recurrent disease.

[Diagnostic and treatment of hypereosinophilia upon return from the tropics: 102 patients]. / Diagnostic et traitement des hypereosinophilies sanguines au retour des tropiques: a propos de 102 patients.

Management of blood eosinophilia in travelers returning from the tropics is controversial. In this prospective study, 102 asymptomatic tropical travelers underwent investigation and treatment for hypereosinophilia. In contrast with direct tests for parasitic infection which were positive in only 15% of cases, immunological tests were suggestive of helminthic infection is 77%. The most common diagnoses were toxocarosis (49%), strongyloidiasis (30%), and filariasis (19%). Anti-parasite treatment was undertaken based on laboratory findings (12 cases) or on presumptive diagnosis using two-agent therapy (ivermectin and praziquantel) in 13 cases or three-agent therapy (ivermectin, praziquantel, flubendazole) in 77 cases. As a result of treatment, eosinophil count returned to normal in 61% of cases and decreased in 30%. These findings suggest that presumptive treatment of blood eosinophilia can be undertaken in tropical travelers using three anti-parasitic drugs: ivermectin (1 x 0.4 mg/kg), flubendazole (2 x 100 mg per day for 3 days), and praziquantel (1 x 40 mg). As a precaution before using ivermectin, tests should be performed to detect loiasis which can lead to adverse reactions.

SEN6, a locus for SV40-mediated immortalization of human cells, maps to 6q26-27.

Normal cells show a limited lifespan in culture and the phenotype of cellular senescence. Tumors and tumor cell lines have typically overcome this form of growth suppression and grow continuously as immortal cell lines in culture. We have exploited the DNA virus SV40 to study the mechanism by which human fibroblasts overcome senescence and become immortal. Multiple steps have now been identified, including inactivation of cellular growth suppressors through direct interaction with SV40 large T antigen and through mutation of a gene on chromosome 6 (designated SEN6). In this study, we sublocalize the site of SEN6 to 6q26-27 based on molecular genetic analysis. Twelve SV40-immortalized fibroblast cell lines share a deletion in this area based on assessment for loss of heterozygostiy (LOH) for seven informative markers on 6q. Two immortal cell lines (AR5 and HALneo) appeared to have retained separate single copies of chromosome 6 despite the fact that they are both derived from the same preimmortal SV40-transformant and should share the same mutated allele of SEN6 (Hubbard-Smith et al., 1992). Detailed analysis by polymerase chain reaction, restriction fragment length polymorphism and fluorescence in situ hybridization shows, however, that although they differ for 17 markers from the centromere to 6q26, they share AR5 derived sequences (eight markers) distal to 6q26 including the minimal deletion region, further supporting the assignment of SEN6 to this region. Since human tumors including non-Hodgkins lymphoma, mammary carcinoma and ovarian carcinoma show LOH in 6q26-27, inactivation of SEN6 may be responsible for immortalization of these tumors as well.

Altered neuronal and microglial responses to excitotoxic and ischemic brain injury in mice lacking TNF receptors.

Brain injury, as occurs in stroke or head trauma, induces a dramatic increase in levels of tumor necrosis factor-alpha (TNF), but its role in brain injury response is unknown. We generated mice genetically deficient in TNF receptors (TNFR-KO) to determine the role of TNF in brain cell injury responses. Damage to neurons caused by focal cerebral ischemia and epileptic seizures was exacerbated in TNFR-KO mice, indicating that TNF serves a neuroprotective function. Oxidative stress was increased and levels of an antioxidant enzyme reduced in brain cells of TNFR-KO mice, indicating that TNF protects neurons by stimulating antioxidant pathways. Injury-induced microglial activation was suppressed in TNFR-KO mice, demonstrating a key role for TNF in injury-induced immune response. Drugs that target TNF signaling pathways may prove beneficial in treating stroke and traumatic brain injury.

Immortalization of human fibroblasts by SV40 large T antigen results in the reduction of cyclin D1 expression and subunit association with proliferating cell nuclear antigen and Waf1.

Protein complexes containing cyclins and cyclin-dependent protein kinases (cdks) have been shown to be rearranged in both spontaneous and viral tumor antigen-transformed cells. We have examined G1- and S-phase cyclin/cdk complexes as a function of the neoplastic progression of human diploid fibroblasts transfected with the SV40 large T antigen. We find that the expression of cyclin D1 and its association with proliferating cell nuclear antigen (PCNA) and Waf1 remain unchanged in precrisis human fibroblasts transfected with SV40 large T antigen. However, in these same cells the association of cdk4 with cyclin D1, PCNA, and Waf1 is disrupted. Upon immortalization, cyclin D1 protein expression is decreased, and binding of both PCNA and Waf1 with the remaining cyclin D1 is reduced. In contrast, large T antigen increased the expression of cyclin A and cyclin E proteins in both precrisis and immortal cells and did not reduce the binding of PCNA or Waf1 to either cdk2 or cyclin A proteins. These results show that large T-antigen expression in human fibroblasts selectively uncouples cyclin D1 from cdk4, and subsequent immortalization of these cells results in additional changes to the cyclin D1-dependent cell cycle regulatory pathways.

Iterative chromosome mutation and selection as a mechanism of complete transformation of human diploid fibroblasts by SV40 T antigen.

The acquisition of an extended lifespan and of neoplastic properties, including anchorage independence, ability to grow in low serum-containing media, morphological transformation, immortalization and tumorigenicity in nude mice were studied in 31 human fibroblast lineages transfected with plasmids containing the SV40 early genes. Plasmids were used that contained sequences for large T alone, or large T plus small t or large T plus small t plus the SV40 origin. Cells expressing large T antigen gradually acquired the ability to form colonies in low serum or to form anchorage-independent colonies. Large T antigen was sufficient to cause complete transformation to tumorigenicity if multi-step lineage evolution was obtained by prolonged serial passage and if in vivo progression was assisted by means of a gelatin sponge implantation technique. Cells derived from progressive tumors initiated in sponges showed enhanced tumorigenicity as measured by ability to obtain tumors without using sponges and with reduced latent period, higher incidence and with fewer cells inoculated. Multiple lineages of human fibroblasts have been converted to tumorigenicity without additional treatments such as transfection with activated oncogenes or exposure to carcinogens. These data, taken in conjunction with earlier studies showing that T antigen causes chromosome mutation preceding and accompanying the accumulation of the neoplastic phenotype, suggests that the T protein drives the transformation process by acting as a mutagen and cells with growth advantages were selected for in vitro and in vivo. With the possible exception of morphological transformation, the presence or absence of genes for small t and the SV40 origin were not critical for the process.

Abrogation of a kinase-mediated G1 cell cycle arrest point is a late event in the neoplastic progression of human fibroblasts transfected with the SV40 large T antigen gene.

Cell cycle arrest points that are sensitive to the kinase inhibitor staurosporine have been shown to have widely differing sensitivities for processes in G1 and G2. In addition, the exquisitely sensitive G1 arrest point has been reported to be abrogated in neoplastically transformed cells. Using a multistep model of the neoplastic process in human cells, we show here that abrogation of the G1 arrest point occurred in 5 of 11 tumorigenic cell populations. The abrogation, in those instances when it occurred, was a late step and associated with the acquisition of tumorigenicity, but apparently independent of conventional criteria for in vitro transformation.

SV40 T antigen induced chromosomal changes reflect a process that is both clastogenic and aneuploidogenic and is ongoing throughout neoplastic progression of human fibroblasts.

In human fibroblasts, the expression of SV40 large T antigen is known to cause a variety of chromosomal aberrations and especially dicentric chromosomes. In some cases, the later aberrations have been reported to be reversible telomeric associations. We report here aberration and chromosome number studies of twenty-nine T antigen positive lineages, studied from their initiation by transfection of T antigen sequences into human diploid fibroblasts, until crisis or immortalization occurred or, in some cases until the lines became tumorigenic in nude mice. The data show that T antigen consistently produced chromosomal instability of both number and structure by an active process that began before transformation indicators were positive and continued throughout neoplastic progression. The most frequently observed aberrations were dicentric chromosomes, which were shown to be true dicentrics by examination by in situ hybridization with telomeric sequences. These data are consistent with the hypothesis that T antigen causes human fibroblasts to become neoplastically transformed by successive rounds of chromosomal mutation and lineage evolution.

Frequent deletions in nine newly immortal human cell lines.

Nine newly immortal lines of human fibroblasts transfected with SV40 T antigen were examined for recurrent chromosome losses. In order of decreasing frequency, all nine lines had three or more of the following minimal deletions specifically associated with the immortalization event: del(6)(q21), del(3)(p24), del(1)(p34), del(4)(p25), del(5)(p14), del(11)(p11), del(11)(q14), del(12)(p12), and del(14)(p?). Many other chromosome changes were not clearly associated with immortalization, but were acquired during other stages of this multistep model of neoplastic transformation. We propose that these chromosome loci associated with immortalization are candidates for the location of genes involved in cellular senescence.

Karyotype evolution in a simian virus 40-transformed tumorigenic human cell line.

Normal human foreskin fibroblasts (HSF4) were transfected using the pSV3-neo plasmid. A pool of 10 G418-resistant colonies, HSF4-T12, showed a progressive increase in the expression of a number of in vitro transformation markers with passage in culture and became immortalized. Although no tumors were formed when cells were injected subcutaneously into nude mice, this cell line produced progressive tumors when cells were injected into preimplanted Gelfoam sponges in the mice. When these tumors were cultured in vitro and subsequently injected subcutaneously, progressive tumors were produced with median latency periods as short as 4 weeks. Three phases of cytogenetic change could be distinguished. At early passages after transfection. HSF4-T12 exhibited many random chromosomal changes. At a time just after immortalization, both flow karyotype and G-banded analyses showed the appearance of balanced clonal rearrangements. These included t(2;4), t(2;14), t(3;?), 6p-, i(6p), 8p-, t(14;15), i(15), and t(18;?). These clonal rearrangements were stable with passage in culture, and less variability from cell to cell was noted. The only consistent chromosomal loss observed was -Y. Analysis of three independent tumors showed characteristic loss of chromosomal material rather than balanced chromosomal rearrangements. Frequent loss of 6q and chromosomes #13, 15, 20, and Y was noted.

Trans-acting factors in chromosomal instability.

The hypothesis that trans-acting factors affect chromosome stability was explored using human X Chinese hamster somatic cell hybrids. Two types of hybrids were examined. In either case, the human parent consisted of human diploid fibroblasts, the chromosomes of which tended to be lost from the hybrid cell. Comparisons were made between hybrid clones in which the hamster parent had a very stable karyotype (line CHO) and clones from a hamster parent with an unusual ongoing unstable karyotype (line CHX). Chinese hamster-human hybrid cell clones were expanded, and metaphase spreads were analyzed with an in situ hybridization procedure that uses biotin-labeled human genomic DNA as probe. Analyses of chromosome numbers and interspecies translocations were made after 20, 60, and 100 population doublings. Throughout the experiments, the generation of human-hamster-translocated chromosomes was more frequent in the hybrid cells with the CHX background. In addition, these cells also generated human acentric fragments, which were rare in cells with the CHO background. These results favor explanations for the instability of the CHX line that involve ongoing production of a diffusible clastogenic factor.

SV40 T antigen alone drives karyotype instability that precedes neoplastic transformation of human diploid fibroblasts.

To define the role of SV40 large T antigen in the transformation and immortalization of human cells, we have constructed a plasmid lacking most of the unique coding sequences of small t antigen as well as the SV40 origin of replication. The promoter for T antigen, which lies within the origin of replication, was deleted and replaced by the Rous sarcoma virus promoter. This minimal construct was co-electroporated into normal human fibroblasts of neonatal origin along with a plasmid containing the neomycin resistance gene (neo). Three G418-resistant, T antigen-positive clones were expanded and compared to three T antigen-positive clones that received the pSV3neo plasmid (capable of expressing large and small T proteins and having two origins of replication). Autonomous replication of plasmid DNA was observed in all three clones that received pSV3neo but not in any of the three origin minus clones. Immediately after clonal expansion, several parameters of neoplastic transformation were assayed. Low percentages of cells in T antigen-positive populations were anchorage independent or capable of forming colonies in 1% fetal bovine serum. The T antigen-positive clones generally exhibited an extended lifespan in culture but rarely became immortalized. Large numbers of dead cells were continually generated in all T antigen-positive, pre-crisis populations. Ninety-nine percent of all T antigen-positive cells had numerical or structural chromosome aberrations. Control cells that received the neo gene did not have an extended life span, did not have noticeable numbers of dead cells, and did not exhibit karyotype instability. We suggest that the role of T antigen protein in the transformation process is to generate genetic hypervariability, leading to various consequences including neoplastic transformation and cell death.