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Biomedical subjects

B Lamy

Publications and source records attributed to B Lamy.

At least 19 recordsLinked to original sources
PubMed2001

Plateletpheresis concentrates produced with the COMTEC cell separator: the French experience.

The latest generation of cell separators such as Trima (Gambro), Amicus (Baxter) and AS-TEC 204 (Fresenius), allow the collection of leucocyte-reduced platelet concentrates without secondary filtration. Fresenius has recently developed the COMTEC cell separator whose performance has been evaluated by several teams in France. This new cell separator is an improved version of the Fresenius AS-TEC 204 cell separator, designed to allow more efficient platelet collections. This study reports on the experience of six French teams (from Bordeaux, Clermont-Ferrand, Creteil, Dijon, Lille and Nancy) who obtained 696 leucocyte-reduced plateletpheresis concentrates in the course of collection using the new Fresenius COMTEC cell separator. All healthy volunteer donors fulfilled French selection criteria for platelet apheresis. Donors were eligible if they had suitable venous accesses, if their bodyweight was *50 kg and if their pre-apheresis platelet count was >150 x 10(9) l(-1). Between 4606 and 5229 ml of blood were processed. The mean volume of the platelet concentrates was between 439 and 493 ml (mean 460 +/- 63 ml). The platelet yield was of the order of 5.18 +/- 1.02 x 10(11) with only one platelet concentrate below the norm of 2 x 10(11) platelets (0.91 x 10(11)). No plausible explanation for this was found. The residual leucocyte levels conform to current norms. The platelet concentrates contained less than 1 x 10(6) leucocytes per concentrate (mean 0.233 +/- 0.150 x 10(6) leucocytes) in more than 97% of the components produced with >95% statistical confidence. The efficacy of the cell separator (52.44 +/- 7.35%) is comparable to that of other separators. The Fresenius COMTEC cell separator makes it possible to obtain leucocyte-reduced platelet concentrates which comply with current standards both in terms of platelet content and residual leucocyte level.

Adult↗
PubMed1999

[Can one use probabilistic protocols for antibiotic therapy in intensive care units?].

Due to a large spectrum, empiric antibiotics treatments participate to the increase in bacterial resistance. In order to improve its indications, the implementation of therapeutic guidelines in an ICU was studied. Empiric therapy was administered in 30% of the 178 patients receiving antimicrobial agents. Large spectrum drugs were prescribed in 26% of empiric treatments. The mean duration of empiric antibiotics administration was 3.2 days. It was concluded that it was possible to use guidelines of empiric antibiotic in an intensive care unit.

Anti-Bacterial Agents↗
PubMed1997

Fortuitous detection of uniparental isodisomy of chromosome 6.

Uniparental isodisomy is defined as the inheritance of two copies of the same parental chromosome and can result in defects when it produces homozygosity for a recessive mutation or in the presence of imprinting. We describe the detection of a chromosome 6 uniparental isodisomy in a 9 year old girl, discovered during a search for an HLA identical sib. HLA typing, erythrocyte phenotyping, and genotypes of microsatellite polymorphisms were compatible with a paternal isodisomy of chromosome 6, with normal biparental origin of the other chromosomes. Paternal cells were not responsive to the patient's cells in mixed lymphocyte cultures. This fortuitous detection of a chromosome 6 isodisomy suggests that cases of chromosome 6 UPD may not be deleterious and may therefore go undetected.

Cells, Cultured↗
PubMed1996

[Immuno-hemolytic transfusion reactions. III. Report of 61 cases].

Blood transfusion is mainly bound to immunological and infectious risks. The immunological risk originates from an incompatibility between the blood of the donor and that of the recipient; this risk remains insufficiently assessed. A multicentre study has been carried out by the French Blood Transfusion Society and the National Institute for Blood Transfusion. Sixty-one accidents due to an erythrocyte incompatibility were found: 26 cases with ABO incompatibility, and 35 cases with alloantibodies of other blood group systems. For the former category of accidents, the most frequent cause was due to a failure in the realization of the bedside ABO check. For the latter, the main problem was the achievement and the interpretation of antibody screening. The long term follow-up shows no chronic after-effects of immunological accidents. For each accident, errors have been identified and analysed. It was proven that they all originate from health care establishments.

ABO Blood-Group System↗
PubMed1996

Novel gene transcripts preferentially expressed in human muscles revealed by quantitative hybridization of a high density cDNA array.

A set of 1091 human skeletal muscle cDNA clone inserts representing more than 800 human gene transcripts were spotted as PCR products at high density on nylon membranes. Replicas of the filters were hybridized in stringent conditions with 33P-radiolabeled cDNA probes transcribed from skeletal muscle poly(A)+ RNA. Hybridization signals were collected on phosphor screens and processed using a software specifically adapted for this application to identify and quantitate each spot. Parameters likely to influence the hybridization signal intensity were assessed to eliminate artifacts. Each clone was assigned to one of four intensity classes reflecting the steady-state level of transcription of the corresponding gene in skeletal muscle. Differential expression of specific gene transcripts was detected using complex cDNA probes derived from nine different tissues, allowing assessment of their tissue specificity. This made it possible to identify 48 novel gene transcripts (including 7 homologous or related to known sequences) with a muscle-restricted pattern of expression. These results were validated through the analysis of known muscle-specific transcripts and by Northern analysis of a subset of the novel gene transcripts. All these genes have been registered in the Genexpress Index, such that sequence, map, and expression data can be used to decipher their role in the physiology and pathology of human muscles.

Blotting, Northern↗
PubMed1996

A genotype study of the c-Ha-ras-1 locus in human bladder tumors.

PURPOSE: To clarify the role of the c-Ha-ras-1 gene in bladder cancer predisposition and prognosis. MATERIALS AND METHODS: The c-Ha-ras-1 locus was studied by Southern blotting in white blood cells and tumor samples obtained from 126 patients with bladder cancer (74 Ta-T1 and 52 T2-T4). A comparison with 84 unaffected patients and a survival analysis were performed. RESULTS: The patients with bladder cancer presented 7 different c-Ha-ras-1 alleles, 12 different genotypes, heterozygosity in 49% of cases and a loss of heterozygosity (in the tumor) in 13 cases. The most frequent allele (a1, 6.6 kb) was present in 83% of patients. Heterozygosity correlated with vascular invasion in the tumor (p < 0.0001). In the small subgroup of 11 patients with rare alleles and genotypes, these alleles and genotypes occurred more often in patients with T2-T4 tumors (p < 0.01 for alleles and genotypes), aneuploid tumors (p < 0.001, p < 0.005) and tumors with vascular invasion (p < 0.01, p < 0.005). However, in this study, the majority of patients with high risk tumors possessed common alleles and genotypes. Survival analysis showed that neither the c-Ha-ras-1 genotype nor allelomorphism was an independent prognostic factor. Elsewhere, no rare allele occurred more frequently in bladder cancer affected patients than in unaffected patients. CONCLUSION: This study confirms c-Ha-ras-1 gene polymorphism in a bladder cancer affected population and, in some cases, a loss of genetic material in the vicinity of this locus. No specific genotype can be implicated in the predisposition to bladder carcinoma, and c-Ha-ras-1 genotyping appears of limited value in the clinical management of these patients.

Chromosome Mapping↗
PubMed1996

Clinical evaluation of cell deoxyribonucleic acid content measured by flow cytometry in bladder cancer.

PURPOSE: We evaluated the clinical value of flow cytometry in bladder cancer. MATERIALS AND METHODS: Deoxyribonucleic acid (DNA) content was measured by flow cytometry in 275 untreated patients with bladder tumor followed for 1 to 8 years. Four pathological parameters (stage, grade, observed vascular invasion and associated carcinoma in situ) and 3 flow cytometric parameters (ploidy, number of aneuploid cell lines and DNA index) were defined. RESULTS: Univariate survival analysis showed that every parameter, when considered separately, was a significant prognostic factor (p < 0.0001 in call cases). Multivariate analysis showed that stage (p < 0.0001), DNA index (p < 0.01) and associated carcinoma in situ (p < 0.05) were independent, significant prognostic factors. However, ploidy and DNA index enhanced prognostic information above the traditional stage and grade only in patients with a stage pT1, grade 3 tumor (p < 0.05). Retrospectively, different therapeutic decisions could have been made using DNA content only in 4% of cases. CONCLUSIONS: In patients with bladder cancer DNA content is an independent predictor of survival but its clinical usefulness is limited.

Aged↗
PubMed1995

The Genexpress Index: a resource for gene discovery and the genic map of the human genome.

Detailed analysis of a set of 18,698 sequences derived from both ends of 10,979 human skeletal muscle and brain cDNA clones defined 6676 functional families, characterized by their sequence signatures over 5750 distinct human gene transcripts. About half of these genes have been assigned to specific chromosomes utilizing 2733 eSTS markers, the polymerase chain reaction, and DNA from human-rodent somatic cell hybrids. Sequence and clone clustering and a functional classification together with comprehensive data base searches and annotations made it possible to develop extensive sequence and map cross-indexes, define electronic expression profiles, identify a new set of overlapping genes, and provide numerous new candidate genes for human pathologies.

Amino Acid Sequence↗
PubMed1995

[IMAGE: molecular integration of the analysis of the human genome and its expression].

We have developed an integrated approach for the analysis of human cDNA libraries from neuromuscular tissues, based on the acquisition of primary structural, expression and mapping data. 26,938 sequence signatures (over 7 million bases) have been derived from both ends of skeletal muscle and brain cDNA clones. Primary redundancy analysis and classification of database similarities made it possible to characterize by structural data about 8,000 human gene transcripts, the majority of which is catalogued for the first time. Collecting hybridization signatures of complex cDNA probes derived from the tissues of origin to cDNA clones arrayed on high density filters provided a global and quantifiable view of the complexity and level of expression of the different transcripts. The development of 2,792 eSTS markers amplifiable by PCR defined the chromosomal localization of some 2,500 genes corresponding to the transcripts sequenced. The data collected are part of the corpus of the human gene transcript catalog and the genic map of the human genome.

Brain Chemistry↗
PubMed1994

Successful response to alpha-interferon 2b in a refractory IgM autoagglutinin-mediated hemolytic anemia.

We describe the beneficial effect of recombinant alpha 2b interferon in a woman with an idiopathic and refractory IgM-mediated autoimmune hemolytic anemia due to low-titer, high-thermal-amplitude cold agglutinins. The response was partial but sustained, 2 months after interruption of interferon, with hemoglobin concentrations ranging between 8.5 and 10 g/dl. In the literature, such rarely encountered hemolyzing warm-reacting agglutinins are described as causing severe hemolysis with a frequently fatal clinical outcome.

Aged↗
PubMed1994

Red cell antibody screening, red cell antibody identification and compatibility testing with the Column Agglutination Technology (CAT). The Bio Vue system.

A new system for irregular antibody screening was described in 1993 by Reis K.J. This test is performed in a microcolumn prefilled with glass microbeads in suspension in a neutral or Anti Human Globulin isotonic solution. When the red cells are sensitized they are trapped by the microbead suspension during column centrifugation. 21365 irregular antibody screenings were performed with this Column Agglutination Technology (CAT) and the results were compared to those obtained with conventional manual tests. The CAT was more efficient than the manual tests. The number of positive samples containing specific antibodies was higher with CAT tests (924 samples) than with manual tests (802 samples). The CAT is easy to perform and the elimination of washing steps decreases the overall test time. It allows the use of this test for pre-transfusion compatibility testing particularly in emergency transfusion cases. The red cell age and more generally the red cell storage conditions seem to be an influential parameter on the percentage of unspecific reactions. In this study the unspecific reaction rate was low but we used only reagent red cells prepared every day. This new technology may be considered as an alternative technology to the Gel Test in Blood Transfusion security.

Blood Grouping and Crossmatching↗
PubMed1993

A transformant of Aspergillus fumigatus deficient in the antigenic cytotoxin ASPFI.

The aspfI gene encoding a ribonucleotoxin, a putative virulence factor of Aspergillus fumigatus, was inactivated by gene disruption. Gene replacement through homologous recombination by the disrupted allele tagged by the hygromycin B resistance marker was performed by transformation of a pathogenic strain. One transformant with the disrupted aspfI gene failed to produce the ASPFI protein and was shown to be pathogenic for mice. We concluded that this ribotoxin is not a main factor in the colonization of the lung tissues by A. fumigatus.

Allergens↗
PubMed1993

Flow cytometry versus urinary cytology in the diagnosis and follow-up of bladder tumors: critical review of a 5-year experience.

The authors report the results of a 5-year experience with flow cytometry (FCM) in the diagnosis and evaluation of bladder tumors. FCM was applied to 400 patients (225 without a urinary tumor and 175 with a past or recent bladder tumor). For the patients without a tumor, bladder-irrigation-fluid FCM was positive in 22% of samples vs 1% of those tested with conventional cytology. The high rate of false-positive results may have been due to an imperfect quality of the samples, to the staining procedure and to the high amount of squamous cells. For 72 selected tumors in which the bladder washing was performed under specific requirements, the detection rate of FCM was lower than that of conventional cytology, including G1-grade tumors. A comparison between bladder-irrigation-fluid FCM and disaggregated-biopsy FCM revealed a 22% rate of discordant results. From these data it does not seem desirable tu use bladder-irrigation FCM instead of conventional cytology in routine urologic examinations. The use of this technique must be more selective in bladder tumor evaluation.

Aged↗
PubMed1993

First results obtained in France with the latest model of the Fresenius cell separator: AS 104.

In Besançon, we carried out 40 plateletphereses with the latest model of the Fresenius cell separator AS 104 to check this new system against the new generation of cell separators, according to the following criteria: less than 2x10 6 leukocytes (before filtration) and more than 5x10 11 platelets. The results show that platelet concentrates contained 5.04+/-0.88x10 11 platelets in a total volume of 435+/-113 mL. The mean platelet recovery was 40.95+/-4.86% (from 31.7 to 51.6). The leukocyte content was 2.28+/-5.48x10 6 and the red blood cell contamination was 3.48+/-2.38x10 8. The quality of the platelets was very satisfactory. There was no problem with donor biocompatibility or procedure safety, few adverse donor reactions (0.6%) and good therapeutic efficiency of platelet concentrates.

Cell Separation↗
PubMed1991

Isolation and nucleotide sequence of the Aspergillus restrictus gene coding for the ribonucleolytic toxin restrictocin and its expression in Aspergillus nidulans: the leader sequence protects producing strains from suicide.

We describe the cloning and characterization of the gene coding for the ribotoxin restrictocin, from Aspergillus restrictus (gene res, EMBL accession Number X56176). This toxin is a potent inhibitor of protein synthesis in eucaryotes and is of potential interest as a component of immunotoxins. To analyze the mechanism of self-protection in the producing organism, the res gene was cloned into the vector pFB39 and introduced into Aspergillus nidulans. The secretion of active restrictocin from transformants suggests that the pro-toxin is not an active nuclease but is activated during the process of secretion.

Allergens↗