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Biomedical subjects

M Nicolas

Publications and source records attributed to M Nicolas.

At least 19 recordsLinked to original sources
PubMed2006

[Intestinal parasitosis in French West Indies: endemic evolution from 1991 to 2003 in the University Hospital of Pointe-a-Pitre, Guadeloupe].

Guadeloupe is one of the French West Indies, where, until 1960, intestinal parasitic infections were endemic. In the microbiological laboratory of the university hospital of the island, we carried out a retrospective study of the 17,660 stool examinations received from 1991 to 2003. All the stool specimens were examined using at least a wet mount preparation and a concentration method (Bailenger). Specific techniques such as Ziehl-Neelsen modified acid fast stain, chromotrope staining procedure or Baermann's technique were used when indicated. A parasite considered as really pathogenic is detected in only 5.6% of the cases of the 17,660 stool examinations. The intestinal protozoa count for 10.8% of them, G. intestinalis (60%) is the most common, followed by Cryptosporidium sp (26%) and Isospora belli in AIDS patients while Entamoeba histolytica/dispar rarely appears (2.3%). Among the parasitic intestinal helminths, Strongyloïdes stercoralis is seen as the most prevalent (82%) whereas hookworms and Trichuris trichuria count respectively for 9.8% and 5.6%. Schistosoma mansoni appears as an exception. This epidemiological change for intestinal parasitic infections results from the improvement of socio-economic and sanitary way of living of the population. However the persistence of the strongyloidiasis constitutes the outstanding fact in a area of strong prevalence of the HTLV1 infection.

Endemic Diseases↗
PubMed2005

[Dynamic evaluation of lower limb arteries using the ECTRICKS MRI technique].

PURPOSE: This article presents a new MR angiography technique, Elliptic Centric Time Resolved Imaging on Contrast KineticS (ECTRICKS), which allows dynamic evaluation of the lower limb arteries opacification when venous return prevents adequate diagnostic evaluation of calf arteries. PATIENTS AND METHODS: Comparative examinations could be compared. Additional arteries in 59 patients using a standard MRA technique and the ECTRICKS technique. RESULTS: A total of 33 examinations could be compared. Additional arteries could be evaluated in 10% of our patient population using the ECTRICKS technique, and in 20% for our diabetic population. Arterial evaluation was better with the ECTRICKS technique in patients with diabetes and venous insufficiency. CONCLUSION: ECTRICKS is a good complementary sequence for evaluation the calf arteries in patients with diabetes or early venous return.

Adult↗
PubMed2005

[Lymphoepithelial cyst of the pancreas: a case report].

Lymphoepithelial cyst is a rare benign dysembryoplastic lesion of the pancreas, difficult to diagnose before surgery. The authors report the case of a 44 year old man with low left sided chest pain. CT-scan described a multilocular cystic tumor of the tail of the pancreas. The patient underwent a distal pancreatectomy with splenectomy. Histologic analysis led to the diagnosis of lymphoepithelial cyst of the pancreas. Through this observation, the authors stress the value of imaging in this benign entity that must be considered when evaluating a cystic pancreatic lesion because a different therapeutic approach may be required.

Adult↗
PubMed2005

Retrospective review of leptospirosis in Guadeloupe, French West Indies 1994-2001.

Demographic, clinical, biological and personal data were obtained from patients hospitalized with symptoms of leptospirosis in the Hospital of Pointe a Pitre, Guadeloupe, French West Indies from 1994 to 2001. Of the 897 screened patients, 212 were acute cases, 607 were non-infected and 78 were undetermined cases. There was no predominant age group. Leptospirosis transmission followed the rainfall cycle and was greater in rural areas. Jaundice and conjunctival suffusion were significantly more frequent in cases than non-cases. Males, professions considered to be at risk and contact with swine or bovine were associated with infection. Serogroups Icterohaemorrhagiae, Cynopteri, Australis, Sejroe, Pomona and Ballum were serovars presumed responsible for acute cases.

Adult↗
PubMed2004

Lymphoplasmacytic hyperplasia (possibly pre-PTLD) has varied expression and appearance in intestinal transplant recipients receiving Campath immunosuppression.

Posttransplant lymphoproliferative disorders (PTLD) are a frequent complication in bowel transplant recipients. Histological changes in PTLD range from expansile lymphoplasmacytic (LP) hyperplasia to frank lymphoma. Small bowel allograft biopsies obtained in the first 250 days posttransplant were retrospectively graded after patients had received induction immunosuppression with either anti-CD52 (Campath) or anti-CD25 (Zenapax) monoclonal antibodies. The biopsies were analyzed with respect to the onset intensity of lymphoplasmacytic infiltrates and presence of in situ EBV hybridization (EBER) positivity. We observed that lymphoplasmacytic infiltrates were a frequent change in all bowel transplant patients over the examined period. Campath-treated patients developed earlier LP infiltrates of mild to moderate intensity between day 1 and 100 posttransplant, thereafter decreasing to mild. No EBER positivity was detected in this group. Zenapax-treated patients presented with LP infiltrates later of mild to moderate intensity through day 100 posttransplant. However, more persistent and intense LP infiltrates was observed after day 101 in this group, including a case of lymphoma and two cases of EBER positivity. We conclude that Campath immunosuppression results in an earlier appearance of LP lesions that are generally less intense than those evident with Zenapax. We attribute these findings to the more profound immunodeficiency and cell targeting following Campath treatment.

Alemtuzumab↗
PubMed2004

[Secondary diseases of the peritoneum].

Most inflammatory, infectious or tumoral diseases of the bowel and abdominal organs may secondarily involve the peritoneum which acts as a mirror of the diseases. Multidetector CT allows breathhold acquisitions through the abdomen and pelvis providing high spatial and contrast resolution imaging at all phases of contrast distribution as well as MPR and 3D capabilities.

Abdominal Neoplasms↗
PubMed2004

Epidemiologic study of the association between human T-cell lymphotropic virus type 1 and Strongyloides stercoralis infection in female blood donors (Guadeloupe, French West Indies).

This case control study was conducted among female blood donors in Guadeloupe. A total of 85 HTLV-1 positive subjects were matched by age (+/- 5 years) in a 1:3 ratio to 255 HTLV-1 negative controls. The mean age was 48.5 and 48.9 years respectively. Ethnic, environmental and socio-economic risk factors were studied. Four risk factors were found independently associated with HTLV-1 seropositivity: Strongyloides stercoralis antibodies (OR = 3.6, CI 1.8, 7.3), low socio-economic status (OR = 2.0 CI 1.0, 4.0), low educational level (OR = 2.0 CI 1.0, 4.0) and agricultural activity (OR = 2.8 CI 1.4, 5.6). This logistic regression analysis demonstrates the reality of the association between HTLV-1 carriers and Strongyloides stercoralis, and its association with socio-economic and environmental risk factors.

Animals↗
PubMed2003

Anti-Müllerian hormone levels in serum from human foetuses and children: pattern and clinical interest.

Serum anti-Müllerian hormone (AMH) determination has been used to investigate gonadal development and abnormal sexual differentiation, but until recently, it was based on assays developed by specialized laboratories. A short time ago, a sensitive assay kit was developed commercially (Immunotech-Beckman Coulter) for clinical use. With this method, we established usual levels of serum AMH in fetuses, newborns, and pre-pubertal children, and evaluated the clinical value of this assay. AMH measurement required only 25 microl of sample and could be performed within 3 h. In females, AMH emerged after birth at low levels (median: 4 ng/ml). In males, AMH levels remained stable during fetal life (median: 44.4 ng/ml), peaked in the first months of life to reach a median of 124.7 ng/ml, then fell with wide individual variations. Cord blood AMH levels at birth may be useful to investigate ambiguous genitalia suspected prenatally. In children with isolated microphallus or hypospadias, decreased AMH values are in favor of testis dysfunction. When testes cannot be palpated, a single determination of serum AMH levels can distinguish between anorchia and cryptorchidism.

Age Factors↗
PubMed2003

Fluctuating particle motion during shear induced granular compaction.

Using a refractive index matching method, we investigate the trajectories of particles in three dimensional granular packing submitted to cyclic shear deformation. The particle motion observed during compaction is not diffusive but exhibits a transient cage effect, similar to the one observed in colloidal glasses. We precisely study the statistics of the step size between two successive cycles and observe that it is proportional to the shear amplitude. The link between the microscopic observations and the macroscopic evolution of the volume fraction during compaction is discussed.

Journal Article↗
PubMed2003

Sclerosing mesenteritis in small bowel transplantation: possible manifestation of acute vascular rejection.

BACKGROUND: Acute rejection of human small bowel allografts is characterized by clinical symptoms combined with characteristic morphologic alterations. The typical geographic distribution of acute rejection in the bowel is involvement of the intestinal parenchyma, which can be transmural, particularly when the rejection is more severe. However, little is known concerning the potential for donor-derived soft tissue adjacent to the bowel to become involved by the host alloimmune response. METHODS: We describe a male patient who, several weeks after combined small bowel and liver transplantation, demonstrated sclerosing mesenteritis with vasculitis and acute rejection of the bowel. RESULTS: The vascular lesions in the mesentery demonstrated increased IgG deposition and the patient developed an alloantibody to the donor. CONCLUSIONS: The changes described herein may represent a novel presentation of acute vascular rejection.

Acute Disease↗
PubMed2003

Malaria in Guadeloupe (French West Indies) 1991-2000.

The only islands in the Caribbean that still have endemic malaria are Haiti and the Dominican Republic. Cases of imported malaria occur on the other islands, particularly Martinique and Guadeloupe, due to the movement of people to and from endemic regions that are geographically and/or culturally close. The re-emergence of transmission cannot be ruled out due to the local persistence of the potential vectors, the anopheles mosquitoes. This retrospective study, over a ten year-period (1991-2000), included all of the cases of malaria confirmed by blood tests at Pointe-à-Pitre University Hospital. This hospital is the main healthcare facility in Guadeloupe. Fifty-nine bouts of malaria occurred in 56 patients. The annual incidence was estimated at 2 to 2.5 cases per 100,000 inhabitants. Plasmodium falciparum largely predominated, accounting for over 80% of cases. The only pernicious case observed resulted in the death of the patient. In all cases the patient had recently travelled to an endemic region, except in one case, caused by P ovale which has never been endemic in the Caribbean. African countries accounted for 43% of cases. No Asian or Pacific strains were identified. In all cases, anti-malarial drugs were not taken, taken incorrectly or were inappropriate. All of the cases of malaria reported in Guadeloupe in the last decade were imported and this region cannot be considered to be at risk of malaria infection. However, long-term epidemiological monitoring is necessary, together with specific entomological monitoring.

Adolescent↗
PubMed2001

Notch signaling is a direct determinant of keratinocyte growth arrest and entry into differentiation.

The role of Notch signaling in growth/differentiation control of mammalian epithelial cells is still poorly defined. We show that keratinocyte-specific deletion of the Notch1 gene results in marked epidermal hyperplasia and deregulated expression of multiple differentiation markers. In differentiating primary keratinocytes in vitro endogenous Notch1 is required for induction of p21WAF1/Cip1 expression, and activated Notch1 causes growth suppression by inducing p21WAF1/Cip1 expression. Activated Notch1 also induces expression of 'early' differentiation markers, while suppressing the late markers. Induction of p21WAF1/Cip1 expression and early differentiation markers occur through two different mechanisms. The RBP-Jkappa protein binds directly to the endogenous p21 promoter and p21 expression is induced specifically by activated Notch1 through RBP-Jkappa-dependent transcription. Expression of early differentiation markers is RBP-Jkappa-independent and can be induced by both activated Notch1 and Notch2, as well as the highly conserved ankyrin repeat domain of the Notch1 cytoplasmic region. Thus, Notch signaling triggers two distinct pathways leading to keratinocyte growth arrest and differentiation.

Animals↗
PubMed2001

KCNQ1/KCNE1 potassium channels in mammalian vestibular dark cells.

The high [K(+)] in the inner ear endolymph is essential for mechanosensory transduction in hearing and balance. Several ion channels, including a slowly activating, voltage-dependent, outwardly conducting K(+) channel composed of the KCNQ1 (KvLQT1) and KCNE1 (IsK/minK) subunits, are expressed at the apical surface of vestibular dark cells. We investigated the underlying molecular mechanisms of this conductance using in situ hybridization, RT-PCR, and immunocytochemistry and by tracking the ultrastructural changes of vestibular structures in kcne1(-/-) mice. In the wild type mice, the KCNE1 and KCNQ1 proteins are expressed specifically at the apical membrane of dark cells, as early as gestational day (GD) 17 for KCNE1 while KCNQ1 mRNAs can be detected at GD 18. This is the first demonstration that the two protein components of this potassium channel co-localize in a polarized fashion at the cellular level. Although the vestibular end-organs are normal at birth in kcne1(-/-) mice, they begin to show modifications during postnatal development: we observed an increase in the height of the dark cells, in their number of mitochondria, and in basolateral membrane infoldings. Subsequently, the epithelium degenerates and the endolymphatic space collapses. Similar changes are known to occur in the cardio-auditory Jervell--Lange-Nielsen syndrome which is caused by mutations in the same channel.

Amino Acid Sequence↗
PubMed2001

Inactivation of Notch 1 in immature thymocytes does not perturb CD4 or CD8T cell development.

Notch proteins influence cell-fate decisions in many developing systems. Several gain-of-function studies have suggested a critical role for Notch 1 signaling in CD4-CD8 lineage commitment, maturation and survival in the thymus. However, we show here that tissue-specific inactivation of the gene encoding Notch 1 in immature (CD25+CD44-)T cell precursors does not affect subsequent thymocyte development. Neither steady-state numbers nor the rate of production of CD4+ and CD8+ mature thymocytes is perturbed in the absence of Notch 1. In addition, Notch 1-deficient thymocytes are normally sensitive to spontaneous or glucocorticoid-induced apoptosis. In contrast to earlier reports, these data formally exclude an essential role for Notch 1 in CD4-CD8 lineage commitment, maturation or survival.

Animals↗
PubMed2001

[Incremental lower extremity CT venography, a simplified approach for the diagnosis of phlebitis in patients with pulmonary embolism].

PURPOSE: To demonstrate that incremental CT venography, performed at the time of CT pulmonary angiography, can easily diagnose deep venous thrombosis. Materials and Methods. Retrospective analysis of 152 combined incremental CT venography and CT pulmonary angiography. Results were compared to Doppler US examinations in 18 cases. RESULTS: 61% of venous thrombosis was found on incremental CT examination in case of pulmonary embolism. In 5 cases, isolated venous thrombosis was found without pulmonary embolism. The CT diagnosis of DVT was confirmed by US; CT appeared more accurate than US in the calf. CONCLUSION: CT venography combined with CT pulmonary angiography is a useful tool in order to obtain a comprehensive evaluation for thrombo-embolic disease.

Adolescent↗