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Biomedical subjects

V Siguret

Publications and source records attributed to V Siguret.

At least 37 records · Page 2Linked to original sources
PubMed1989

[Frequency and severity of systemic infections caused by Streptococcus mitis and sanguis II in neutropenic children].

We have retrospectively evaluated 24 sepsis episodes caused by viridans streptococci in 23 neutropenic children during a 21 months period at the Pediatric Hematology Unit of St. Louis Hospital. The underlying malignancies included acute lymphoblastic leukemia, acute non lymphoblastic leukemia, aplastic anemia and solid tumor. In 17 children neutropenia, defined as a neutrophil count of less than 500 per cubic millimeter, was caused by cytotoxic chemotherapy. For 6 other children neutropenia was consequential to pretransplant treatment regimen for autologous bone marrow transplantation including cytotoxic chemotherapy and total body irradiation. All patients had a silicone rubber atrial catheter. In 9 patients sepsis was associated only with fever for less than 48 hours. In 5 other children fever was prolonged more than 72 hours in spite of specific antimicrobial therapy. No other organism was isolated. In 10 patients, however, the infectious syndrome was severe and the features included cardiac failure (7 patients), pneumonia (7 patients) resembling adult respiratory distress syndrome, encephalopathy (3 patients) without meningitis and proteinuria, 7 of these patients needed a management in a pediatric intensive care unit and 2 died in spite of adapted antibiotics. Streptococci were isolated in blood cultures in 23 children.

Adolescent↗
PubMed1988

Identification of a CpG mutation in the coagulation factor-IX gene by analysis of amplified DNA sequences.

In a family with no previous bleeding history, the sister of a single, severely affected haemophilia B patient requested carrier detection and prenatal diagnosis. In Southern blots, using Taq I digested DNA and a factor-IX cDNA probe, a normal invariant band at 1.6 kb was missing in the haemophiliac suggesting the loss of the Taq I site at the 5' end of exon h. A 162 bp sequence which includes the suspected mutant region was amplified by the polymerase chain reaction in each DNA. Two oligonucleotide probes were synthesized and differed by only one base pair which substituted a T for C in the normal Taq I recognition sequence. The amplified DNA was dot-blotted and hybridized with the labelled probes. The altered sequence hybridized to DNA from the affected individual, his sister and her fetus and not to DNA from the normals. The mutation, involving the haemophiliac, his mother, his sister and her fetus, transforms a CGA codon that encodes for arginine in the catalytic domain of the protein into a UGA stop codon.

Adult↗
PubMedDate not supplied

[Myelodysplastic syndromes].

Myelodysplastic syndromes (MDS) are clonal disorders of pluripotent hematopoietic stem cells. MDS occur predominantly over the age of 60 years. The diagnosis of MDS is based on the examination of both blood films and bone marrow aspirate. Diseases such as vitamin B12 and/or folate deficiency, or cytotoxic therapy leading to a marrow dysplasia should be ruled out. Five subtypes are described in the FAB classification : refractory anaemia or refractory cytopenia, refractory sideroblastic anaemia, refractory anaemia with excess of blasts, refractory anaemia with excess of blasts in transformation, chronic myelomonocytic leukaemia. This FAB classification is based on a small number of parameters: percentage of blood and marrow blasts, percentage of ringed sideroblasts and blood monocytes. The anaemia is typically normo- or macrocytic, non regenerative, and in half cases is associated with neutropenia and/or thrombocytopenia. During blood film examination, cell abnormalities have to be notified, i.e. anisocytosis, poikilocytosis of red cells, morphological abnormalities of neutrophils including hypogranulation, hypolobulation, abnormal large platelets. The prognostic and the treatment of MDS depend on the subtype of the FAB classification, the patient's age, the percentage of marrow blasts, the importance of cytopenia, the presence or not of cytogenetic abnormalities and the existence or not of HLA-identical donor.

Diagnosis, Differential↗
PubMedDate not supplied

[Evaluation of a new automatic hematological system: the Advia 70 (Bayer-Diagnostics)].

The Advia 70 hematology system is a new automated analyser manufactured in Texas (USA) by MWI-DANAM and marketed by Bayer- Diagnostics in France. The throughput is 70 complete blood counts (CBC) with leukocyte differential counts (diff) per hour. Three sample modes are proposed: normal mode (180 muL of whole blood), sample saver mode (90 muL) or automatic sampler (180 muL). The principles used on Advia 70 are: 1) electrical impedance for cell counting (WBC, RBC, platelets, MCV) and RBC/plt sizing; 2) multi-dimensional optical system and absorbance for white cell differential. The Advia 70 has been evaluated in our laboratory over a three-week period. Within-run variations of blood counting (CBC & diff) were determined on normal and abnormal patient specimens whereas between run-variations were determined on normal controls. Linearity and detection limits were also tested. The Advia 70 system results were reproducible and reliable. The correlations between the various sample modes were very good. Contamination and store assays were performed. Thirty normal and abnormal samples were successively analysed on the Advia 70 system and on the Advia 120 system which methodologies are different (myeloperoxidase staining coupled with flow cytometry-nuclear lobularity analysis for WBC/Diff, flow cytometry and laser diffraction for RBC/platelets), and the results were compared: despite the different technologies used on both analysers, the correlations were very good (CBC and diff parameters). Finally, we evaluated the leukocyte differential flags on 72 patients samples with abnormal cells, using the blood smear examination as the reference method. In conclusion, the Advia 70 can be used in private and hospital laboratories.

Autoanalysis↗
PubMedDate not supplied

[Myelodisplasic syndromes diagnosed in a geriatric hospital: morphological profile in 100 patients].

Myelodysplastic syndrome (MDS) is particularly common in geriatric practice. As few data are available in very elderly patients, we conducted a 54-month retrospective study in patients over 70 years with MDS diagnosed at Hôpital Charles Foix. Patients with cobalamine, folate or iron deficiency were excluded. Regarding biological and morphologic approaches, MDS patients were classified according to the FAB criteria. We then tempted to reclassify the patients according to the WHO criteria. The Bournemouth scoring system was used as a prognostic tool. During the study period, 100 patients were included, 29 males and 71 females, median age 86 +/- 7 years (70-103). At the time of bone marrow sampling, a peripheral blood cytopenia was documented in 64 patients, a bicytopenia in 27 patients and a pancytopenia in 9 patients. Isolated anaemia (Hb < 12 g/dL) was found in 60 patients and isolated thrombocytopenia (< 150 x 10(9)/L) in 4. Macrocytosis (MCV > 100 fL) was observed in 21 % of the cases. According to the FAB criteria, the 100 patients were classified as follows: refractory anaemia (RA): 79%; RA with ringed sideroblasts (RARS): 8%; RA with excess of blasts (RAEB): 8%; RAEB in transformation: 1%; chronic myelomonocytic leukaemia: 4%. According to the WHO classification, the patients were reclassified as follows: RA (unilineage) (with or without ringed sideroblasts): 10%; refractory cytopenia with multilineage dysplasia with or without ringed sideroblasts (RCMD): 73%; RAEB: 7% (RAEB-1 6%, RAEB-21%); MDS/Myeloproliferative disorder: 4%; unclassified (hypocellularity): 5%; acute leukaemia: 1%. In order to estimate prognosis at the time of the bone marrow aspirate, we calculated the Bournemouth'score: 8 patients scored 0,57 scored 1,25 scored 2,8 scored 3 and 2 scored 4. In this geriatric population, 83% cases of MDS are RA or RCMD (with or without sideroblasts); MDS with excess of blasts are uncommon. Thus, elderly patients under study with MDS were diagnosed at an earlier stage of the disease than younger ones from series published in the literature. Due to frequent comorbidities, geriatric patients may be symptomatic for a slight decrease of haemoglobin level. Therefore, elderly patients are investigated as soon as they present with moderate anaemia that may explain the early MDS diagnosis.

Aged↗
PubMedDate not supplied

[ABO incompatibility and newborn haemolytic disease: two cases with major erythroblastosis].

Two cases of newborn haemolytic disease because of ABO incompatibility are reported. In both cases, blood erythroblastosis exceeded 300 per 100 leukocytes at birth. Both newborns developed early jaundice and one presented with anaemia. Intensive phototherapy begun soon after birth was an effective treatment. The diagnosis of newborn jaundice and the patho-physiological basis of haemolytic disease because of ABO incompatibility are discussed.

ABO Blood-Group System↗
PubMedDate not supplied

[Plasma cell leukaemia].

We report a case of primary plasma cell leukaemia, with an absolute count of plasma cells of 53 Giga/L, diagnosed in a 83-year-old woman. The patient's condition improved, with no circulating plasma cells after 3 weeks of treatment, in response to the combination of thalidomide and dexamethasone administered for 5 days followed by thalidomide alone. The clinical presentation, the morphological, flow cytometric and pathophysiological characteristics of the plasma cell leukaemia and the treatment are summarised in this paper.

Aged, 80 and over↗
PubMedDate not supplied

[Prescribing guidance pocket chart on the initiation of warfarin therapy in a geriatric hospital: a useful but challenging tool].

Elderly patients are at high risk of over-anticoagulation and of haemorrhagic risk when on warfarin, especially during treatment induction. In Charles Foix Hospital, a 800-bed geriatric hospital, we specifically developed for in-patients older than 70 years (target INR 2.5) a simple low-dose warfarin induction regimen. The dosing recommendations were summarized on a prescribing guidance pocket chart. Eighteen months after the distribution of the chart, we conducted a one-year observational study in order to evaluate: i/ the time needed to achieve the warfarin maintenance dose; ii/ the prescriber'adherence to the recommendations; iii/ the benefit for elderly patients receiving warfarin therapy. The mean time needed to achieve the warfarin maintenance dose was 12.3 +/- 7.0 days for the 89 patients included in the study: 10.6 +/- 5.9 days for the 30 patients whose prescribers followed the recommendations versus 13.5 +/- 7.6 days for the 59 patients whose prescribers did not follow the recommendations. There is a trend to a more frequent over-anticoagulation in patients whose prescribers did not follow the recommendations. The duration of the heparin-warfarin overlap was significantly shorter when the recommendations were followed. Finally, the reasons for non-adherence to the recommendations were analyzed. This study illustrates an assessment of practice in an health care institution.

Aged, 80 and over↗
PubMedDate not supplied

[Biological diagnosis of hemoglobinopathies by phenotype analysis].

Haemoglobinopathies are defined by the presence of qualitative and/or quantitative globin chains abnormalities. In most cases, laboratory diagnosis relies on phenotype analysis. Ethnic group, clinical data, complete blood count in absence of recent blood transfusion, iron status, should be taken into account for the diagnosis. Electrophoresis using an alkaline pH buffer system is used as an initial technique for the detection of haemoglobin variants, showing abnormal bands as compared with reference samples. Isoelectric focusing is more resolutive and could be preferred for this reason: If the migration pattern differs from normal, additional confirmatory tests, as citrate agar electrophoresis (acid pH), are required. Relative amounts of variant haemoglobin (Hb A2, F and S...) are quantified using chromatographic methods. Other tests, such as solubility tests, stability tests, Kleihauer-Betke test, are useful in specific cases. The diagnosis relies on clinical and laboratory findings. In the Paris area, the most common variant is Hb. S. Taalassemia traits are also very common. Screening of SS. S beta D. SO Arab, SD Punjab, SC, or thalassaemia major should be made early so that patients found to have one of these varieties should be referred to haemoglobinopathy centers.

Chromatography↗
PubMedDate not supplied

[Evaluation of hemostasis in venous thromboembolism pathology].

Thromboembolic disease results from an hypercoagulable state and multifactorial causes may lead to hypercoagulability. Thrombogenic risk factors can be acquired and/or inherited. For each thrombophilic patient, the main clinical features retained are: the patient age, the familial history, the recurrence of thromboembolic events, an unusual site of thrombosis. Anti-phospholipid antibodies, which are considered as acquired thrombogenic risk factors, can be detected with coagulation tests and/or Elisa methods. The association of antiphospholipid antibodies with thrombosis is defined as the anti-phospholipid syndrome. Last decades, genetic risk factors were identified. First of all, antithrombin, protein C and protein S deficiencies were described. These deficiencies are involved in about 10% of patients who develop thrombosis before the age of 50. In 1993, a new genetic risk factor was discovered: activated protein C resistance which is due to the Q506 mutation in factor V. This defect represents the most prevalent abnormality of inherited thrombophilia, affecting 20 to 40% of thrombophilic patients. Interestingly, hyperhomocysteinemia, known as potentially predisposing to arterial disease, was also recognized as a risk factor for venous occlusive disease. Several genes encoding homocystein metabolism enzymes, such as cystathionine beta-synthase or methylenetetrahydrofolate reductase are concerned. Establishment of a causal association between the presence of a biological abnormality and the occurrence of thrombosis may lead to an adapted prophylaxis whatever the risk situation.

Antiphospholipid Syndrome↗