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Biomedical subjects

G Bertrand

Publications and source records attributed to G Bertrand.

At least 19 recordsLinked to original sources
PubMed2006

Predictive value of sequential maternal anti-HPA-1a antibody concentrations for the severity of fetal alloimmune thrombocytopenia.

BACKGROUND: Fetal/neonatal alloimmune thrombocytopenia results from maternal immunization against fetal platelet alloantigens (HPAs), and the major risk is intracranial hemorrhage. The severity of thrombocytopenia increases in subsequent pregnancies, and antenatal therapy has been developed. Until now, the fetal status can only be assessed by fetal blood sampling, which carries a risk of fetal loss or premature delivery. OBJECTIVES: To develop non-invasive methods to gain information on the fetal condition. PATIENTS/METHODS: Quantification of the maternal anti-HPA-1a alloantibody concentration was performed with a standardized monoclonal antibody-specific immobilization of platelet antigens (MAIPA) procedure for 43 mothers. A correlation between this concentration and the fetal/neonatal platelet counts was studied. RESULTS: (i) Before antenatal therapy, there was a significant correlation between maternal anti-HPA-1a concentrations > or =250 AU mL(-1) and fetal thrombocytopenia (2-66 x 10(9) L(-1)) whatever the gestational age (Fisher's exact test P = 0.0021). (ii) During subsequent pregnancies, we observed a decrease of the maternal anti-HPA-1a concentration for 14/19 women. Just before delivery, all women had anti-HPA-1a concentrations <250 AU mL(-1). In four cases, there was a therapy failure and the severely thrombocytopenic babies required postnatal therapy. CONCLUSION: The maternal anti-HPA-1a concentration could provide obstetricians with clinically useful information concerning the appropriateness and the timing of invasive monitoring procedures. However, though we observed a tendency toward a decrease in maternal antibody concentration after treatment, this finding does not allow us to draw any conclusions on the effectiveness of therapy.

Antigens, Human Platelet↗
PubMed2004

Germline mutations of the INK4a-ARF gene in patients with suspected genetic predisposition to melanoma.

Germline anomalies of the INK4a-ARF and Cdk4 genes were sought in a series of 89 patients suspected of having a genetic predisposition to melanoma. Patients were selected based on the following criteria: (a) familial melanoma (23 cases), (b) multiple primary melanoma (MPM; 18 cases), (c) melanoma and additional unrelated cancers (13 cases), (d) age at diagnosis less than 25 years (21 cases), and (e) nonphoto-induced melanoma (NPIM; 14 cases). Mutations of INK4a-ARF and Cdk4 were characterised by automated sequencing, and germline deletions of INK4a-ARF were also examined by real-time quantitative PCR. Seven germline changes of INK4a-ARF, five of which were novel, were found in seven patients (8%). Four were very likely to be pathogenic mutations and were found in three high-risk melanoma families and in a patient who had a pancreatic carcinoma in addition to melanoma. Three variants of uncertain significance were detected in one MPM patient, one patient <25 years, and one NPIM patient. No germline deletion of INK4a-ARF was found in 71 patients, and no Cdk4 mutation was observed in the 89 patients. This study confirms that INK4a-ARF mutations are infrequent outside stringent familial criteria, and that germline INK4a-ARF deletions are rarely involved in genetic predisposition to melanoma.

Adolescent↗
PubMed2004

Characterization of human FCGR3B*02 (HNA-1b, NA2) cDNAs and IMGT standardized description of FCGR3B alleles.

The low-affinity Fc gamma receptor IIIb (Fc gamma RIIIb and CD16b) is constituted by a unique FCGR3B polypeptide chain that comprises two extracellular immunoglobulin-like domains, and is expressed as a glycosylphosphatidyl inositol-anchored receptor on the neutrophils. The FCGR3B chain bears allotypes that define the human neutrophil antigen-1 (HNA-1 and NA) system involved in major post-transfusional reactions. FCGR3B is highly homologous to FCGR3A, which is expressed as a transmembrane receptor on natural killer cells and monocytes/macrophages. Its transcription products were not yet fully characterized. In the present work, we sequenced FCGR3B cDNAs with complete 3' untranslated region from purified granulocytes of HNA-1b/HNA-1b (NA2/NA2) genotyped donors. We characterized two FCGR3B cDNAs of different lengths corresponding to two polyadenylation sites. This result was corroborated by data raised by serial analysis of gene expression (SAGE). FCGR3B allele polymorphisms, from this article [FCGR3B*02 (HNA-1b, NA2)] and from the literature, are described for the first time according to the IMGT standardized nomenclature and to the IMGT unique numbering for C-LIKE-DOMAIN (http://imgt.cines.fr). These rules, described in the IMGT Scientific chart, are based on the IMGT-ONTOLOGY concepts. IMGT allele alignments and IMGT Collier de Perles graphical two-dimensional representations are provided for the two Ig-like domains (or C-LIKE-DOMAINs) [D1] and [D2] of FCGR3B*02. The standardized description of FCGR3B allele polymorphisms was approved by the IMGT Nomenclature Committee (IMGT-NC) and is freely available in IMGT repertoire at IMGT, http://imgt.cines.fr.

Alleles↗
PubMed2001

(Amino)(aryl)carbenes: stable singlet carbenes featuring a spectator substituent.

Several (amino)(aryl)carbenes have been shown to be stable at room temperature in solution and in the solid state. Electroneutrality of the carbene center is ensured by the amino group, which has both pi-donor and final sigma-acceptor electronic character. The aryl group remains a spectator substituent, as shown by single-crystal x-ray analysis and by its chemical behavior. Because only one electron-active substituent is needed, numerous stable carbenes will become accessible, which will open the way for new synthetic developments and applications in various fields.

Journal Article↗
PubMed2001

Prognostic factors in localized primary synovial sarcoma: a multicenter study of 128 adult patients.

PURPOSE: To identify most significant and therapeutically relevant prognostic factors in adults with localized primary synovial sarcomas (SS) and to confirm the usefulness of the French Federation of Cancer Centers (FNCLCC) grading system, the prognostic impact of which has been already proven in soft tissue sarcomas. PATIENTS AND METHODS: Data on 128 patients with nonmetastatic SS collected from a cooperative database by the FNCLCC Sarcoma Group between 1980 and 1994 were studied retrospectively. Immunohistochemistry was performed at diagnosis in 77 cases (61%). The tumors were classified as biphasic (n = 45), monophasic fibrous (n = 72), and poorly differentiated (n = 10) subtypes. Histologic grade was determined according to the FNCLCC method, and vascular invasion was assessed in every case. RESULTS: The 5-year disease-specific survival (DSS) rate for this series of patients with localized SS was 62.9% (+/- 9.6% [SD]) with a median follow-up time of 37 months (range, 8 to 141 months). In multivariate analysis, the adverse risk factors associated with decreased DSS were International Union Against Cancer/American Joint Committee on Cancer stage III/IVA disease, male sex, and truncal tumor locations. For metastasis-free survival (MFS), disease stage III/IVA, tumor necrosis, and monophasic subtypes were the major factors associated with a less favorable prognosis. Separately, when not using disease stage, tumor necrosis, and mitotic activity, histologic grade became the most significant prognostic factor for both DSS and MFS. In addition, larger tumors and older patients become associated with a significantly worse prognosis. Independent adverse risk factors for local recurrence-free survival included histologic grade 3 and truncal tumor location. CONCLUSION: These data confirm that not all SS present the same severe outcome. High-risk patients identified on the basis of these parameters may qualify for an aggressive treatment approach.

Adult↗
PubMed2001

Plasma chitotriosidase activity in beta-thalassemia major: a comparative study between Sicilian and Sardinian patients.

BACKGROUND: Chitotriosidase is a functional chitinase secreted by activated macrophages, which is extremely increased in plasma of patients with Gaucher disease (beta-glucocerebrosidase deficiency). Recently, we found that chitotriosidase plasma levels were increased to a variable extent in Sicilian patients with beta-thalassemia major. The aim of this study is to elucidate the possible mechanisms underlying chitotriosidase overproduction in beta-thalassemia major. METHODS: Plasma chitotriosidase was measured in 134 patients with beta-thalassemia major (64 from Sardinia and 70 from Sicily), which are treated chronically by blood transfusions leading to systemic iron overload. They all have peripheral anemia and enormous enlargement of the reticulo-endothelial system. RESULTS: Plasma chitotriosidase activity was found most frequently elevated among Sardinian (48.4%) than Sicilian (17.1%) patients. In either group, the highest levels of plasma chitotriosidase were observed in patients with the highest degree of iron overload, suggesting that this factor could trigger chitotriosidase overproduction. CONCLUSIONS: The higher rate of subjects with increased plasma chitotriosidase values among Sardinian than Sicilian could be related to distinct molecular basis of beta-thalassemia and environmental features.

Female↗
PubMed2000

A cyclic carbanionic valence isomer of a carbocation: diphosphino analogs of diaminocarbocations

Diaminocarbocations (or amidinium salts) feature a three-center 4pi electron system with an open planar structure. Their 2pi electron three-membered cyclic valence isomers, in which the carbon atom bears a negative charge, are predicted to be about 541 kilojoules per mole higher in energy than the open form. This isomer has not been identified yet. In contrast, the attempted synthesis of a diphosphorus analog of amidinium salts leads to the cyclic carbanionic form. There is no precedent for such a transformation of a carbocationic center into a carbanionic center, but with the help of heavier main-group elements, numerous examples can be imagined. This approach will enable the preparation of many unknown structural moieties that are difficult or even impossible to access in the corresponding carbon and nitrogen series.

Journal Article↗
PubMed2000

Stable versions of transient push-pull carbenes: extending lifetimes from nanoseconds to weeks

A (phosphanyl)(trifluoromethyl)carbene is shown to be stable for weeks in solution at temperatures up to -30 degrees C. Its chemical behavior exactly matches that of its transient congeners, even to the extent that subtle effects, such as the recently discovered weak pi interaction with aromatics, are observed. The influence of substituents on the structure of push-pull carbenes is demonstrated by a single-crystal x-ray diffraction study of a (phosphanyl)[2, 6-bis(trifluoromethyl)phenyl]carbene. The lifetime of these molecules makes them accessible to a wider range of standard techniques, allowing their chemical and physical behaviors to be studied in more detail than was previously possible.

Journal Article↗
PubMed2000

Evidence that ventrolateral thalamotomy may eliminate the supraspinal component of both pathological and physiological tremors.

Ventrolateral (VL) thalamotomy produced a marked reduction of oscillations related to the supraspinal components of Parkinson's disease tremor (4-7 Hz) and physiological tremor (8-12 Hz). Finger tremor was examined in nine patients undergoing unilateral VL thalamotomy and in nine age-matched controls. In comparison to the preoperative state, the relative percentage of power within the 7.6-12.5 Hz band did not increase after the surgical procedure. Furthermore, the amount of absolute power within the 7.6-12.5 Hz band was much lower for post-surgical patients in comparison to matched controls when periods of tremor having equal amplitudes were compared. These results suggest that VL thalamotomy interrupts a common circuit involved in the supraspinal component of both physiological and pathological tremors. We provide evidence that the thalamus may be involved in circuits generating physiological tremor in humans.

Adult↗
PubMed2000

Absence of microsatellite instability in transitional cell carcinoma of the bladder.

OBJECTIVES: To investigate the prevalence of the microsatellite instability related to mismatch repair (MMR) gene defects using a panel of six microsatellite markers, as recommended by a recent workshop on microsatellite instability in colon cancer, because it is still unclear whether abnormalities in DNA MMR genes are involved in transitional cell carcinoma (TCC) of the bladder. METHODS: Three mononucleotide repeats (BAT26, TGFbetaRII, and BAX) were studied in 33 TCC samples and in four bladder cancer cell lines. Three dinucleotide repeats (D2S123, D5S346, and D17S250) were studied in 21 of these 33 TCC samples. RESULTS: No alteration was detected either in the 33 TCC samples analyzed or in the four bladder cancer cell lines (T24, J82, 647V, and 1207) studied. A difference between normal and tumor DNA was observed in only 1 of 21 tumor samples for D17S250. CONCLUSIONS: These data indicate that microsatellite instability is very uncommon in TCC of the bladder.

Aged↗
PubMed2000

Comparison of the Bard Trak test with voided urine cytology in the diagnosis and follow-up of bladder tumors.

OBJECTIVES: To compare the results of the BTA Trak test with voided urine cytology (VUC) in the diagnosis and follow-up of bladder tumors. PATIENTS AND METHODS: Urine samples were obtained from 53 patients with bladder tumor (77 samples) and 53 patients treated for bladder tumor with no evidence of disease on the basis of cystoscopic evaluation (88 samples). Urine samples were collected prior to cystoscopy. The BTA assay was performed by the BTA Trak test according to the manufacturer's recommendations. A value >14 U/ml was considered abnormal. RESULTS: There was a statistically significant increase in median BTA value with increasing stage of tumor: 11.9, 57.9 and 391.0 U/ml respectively for stages pTa, pT1 and pT2/3 (p<0.0001, Kruskal-Wallis test). There was also a correlation between increasing grade and median BTA values measured at 6.9, 13.1 and 235.0 U/ml in grades 1, 2 and 3 tumors respectively (p<0.0001, Kruskall-Wallis test). The overall sensitivity of the BTA Trak test was 58.4% compared to 46.7% for VUC, a difference of 11.7%, which was statistically significant (McNemar test, p<0.005). The sensitivity of both tests combined was 63.6%. The specificity of the VUC (94.3%) was significantly higher than that of the BTA Traktrade mark (75.0%) (p<0.005, McNemar test). The accuracy of the Bard Trak test (67.3%) was similar to that of VUC (66.9%). CONCLUSION: The BTA Trak test is more sensitive than urinary cytology in the detection of bladder tumors but the improvement involved is insufficient to consider decreasing the frequency of endoscopic examinations in the follow-up of superficial bladder tumor.

Antigens, Neoplasm↗