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Biomedical subjects

C Fretz

Publications and source records attributed to C Fretz.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Why remove leukocytes from labile blood products in 1995?].

During the last 15 years, the techniques to prepare leukocyte-poor cellular blood components greatly improved, as well as our knowledge about the role of leukocytes in many adverse effects of transfusion. These two facts favor the extension of indication of leukocyte-poor blood components. Leukocytes in blood components may be detrimental to their storage, due to their metabolic needs and to their progressive lysis, leading to the release of cytokines. Leukocytes are the exclusive vector in blood of CMV and HTLV viruses. Leukocytes are a key element of the immune modifications induced by transfusion. HLA alloimmunization is favored by the transfusion of large quantities of leukocytes HLA different from the recipient whose immune functions are intact. Conversely, the risk of transfusion associated graft versus host disease is dependent of the transfusion of mature T lymphocytes sharing a partial identity with the recipient, and/or an immune deficient status of the recipient. Between these two extremes, many other effects related to the presence of leukocytes in cellular blood components, as are the transfusion effect observed in transplant recipients, the increased risk for bacterial infection after transfusion, the increased risk for tumor recurrence or the reactivation of virus infections, remain to be fully understood. Despite recent significant improvements, further studies, experimental as well as clinical, will be needed to expand the indications of leukocyte-poor blood components.

Bacterial Infections↗
PubMed1996

Hepatitis C virus (HCV) genotype analysis in apparently healthy anti-HCV-positive Parisian blood donors.

BACKGROUND: As only a few studies have examined the prevalence of various hepatitis C virus (HCV) subtypes in blood donors, information about the variability and route of infection in apparently healthy persons is limited. STUDY DESIGN AND METHODS: Blood donations collected at a large Parisian hospital (52,441) were investigated for antibodies to HCV. Serum samples were screened with an enzyme immunoassay. All HCV-positive donations were retested with a second enzyme immunoassay and confirmed by immunoblot. The HCV genotype was determined for all polymerase chain reaction-positive subjects. Untypable genotypes were sequenced in the NS5B region. RESULTS: In total, 83 (0.26%) blood donors were anti-HCV positive. Men (0.34%) were significantly more likely to be infected (p < 0.001) than women (0.19%). Prevalence rates in men between 20 and 39 years of age were higher than those in similar women (p = 0.01), but greater in women aged from 50 to 65 years (p = 0.05). Fifty-five sera were viremic, of which 49 could be genotyped by a line probe assay. One new HCV type 1 subtype and three new HCV type 2 subtypes were discovered. In total, 28, 10, 11, 5, and 1 serum samples were grouped into HCV types 1 through 5, respectively, involving a total of 13 subtypes. The mean age of HCV type 2-infected donors was 42 +/- 11 years, but that for type 3-infected subjects was only 30 +/- 4 years (p = 0.0048). Forty-nine subjects showed elevated alanine aminotransferase levels; 39 (80%) of these subjects were viremic (p < 0.05). CONCLUSION: Among the sampled population, an HCV prevalence rate of 0.26 percent was found, with the five most common European genotypes causing the infections. Four new subtypes were discovered. Correlation between genotype and risk factors was not apparent, but links with age, sex, and ethnic origin emerged.

Adult↗
PubMed1995

[Magnetic resonance tomography of hypophyseal tumors].

After describing the topographical anatomy of the pituitary gland, the sellar and parasellar region, in magnetic resonance (MR) imaging, the morphology of pituitary adenomas in MR imaging will be discussed and illustrated, with special reference to differential diagnostic aspects. The diagnostic information and the present clinical relevance of MR imaging, both in pretherapeutic and follow-up situations, will be considered. This will be done using unenhanced and gadolinium-enhanced T1-weighted spin-echo sequences in coronal as well as in sagittal cross sections at 1.5 tesla. Using MR imaging, questions of therapeutic significance concerning the definition of the tumor (evidence of its presence, size, the extent and the degree of infiltration) can be answered with greater precision. The procedure can be repeated with consistency. The contribution of magnetic resonance imaging to tissue characterization is limited. The latter requires consideration of the clinical symptoms and endocrine laboratory findings for differential diagnostic purposes. As disadvantages of MR imaging we should mention the exclusion of certain classes of patients (e.g. those with cardiac pacemaker), the limited potential for evaluation of the extent of invasion of the dura, poor visualization of calcification and insufficient recognition of changes in compact bone.

Adenoma↗
PubMed1995

HCV infection in a rural population of the Central African Republic (CAR): evidence for three additional subtypes of genotype 4.

The prevalence of hepatitis C virus (HCV) antibodies, HCV infection, and genotypes was studied in a rural population of the Central African Republic. In five villages, blood samples were taken from all the inhabitants present during the survey, belonging to Pygmies (299) and to Bantu and Banda ethnic groups (247). Using a second-generation ELISA screening and confirmation by immunoblot assay for the detection of HCV antibodies, all the Pygmies were negative, whereas seven Bantus/Bandas, aged > 35 years and with no familial relationship, were positive, giving a prevalence of 2.8% in this ethnic group. Five samples were also PCR positive; all belonged to genotype 4, but with three new subtypes identified by phylogenic analysis. These results indicate the co-existence of different HCV subtypes and raise questions about the natural transmission of HCV in this secluded population.

Adolescent↗
PubMed1994

Severe inflammatory upper airway stenosis in ulcerative colitis.

Severe upper airway stenosis was diagnosed in a 23 year old woman who presented with hoarseness, cough and dyspnoea 8 yrs after initial diagnosis of ulcerative colitis. The respiratory symptoms worsened over the next few months, the patient eventually developing dysphagia and ultimately severe upper airway obstruction. The narrowest site was the glottis, which was severely stenosed by inflammatory swellings. Systemic corticosteroids led to rapid clinical improvement and restoration of normal airway patency within a few months. Ulcerative colitis is frequently associated with extraintestinal inflammatory manifestations. In the respiratory tract these usually take the form of chronic bronchitis, which occasionally develops into bronchiectasis. This case confirms that the inflammation can also involve the larynx and large airways.

Adult↗
PubMed1993

Post-transfusional anti-HCV-negative, non-A, non-B hepatitis. (I) a prospective clinical and epidemiological survey.

Despite the identification of hepatitis C virus (HCV) and the detection of anti-HCV antibodies in the serum of infected individuals, a sizeable proportion of patients who develop transfusion-associated acute non-A, non-B hepatitis following surgery do not develop anti-HCV antibodies. The cause of this disease remains unknown. To assess the role of homologous blood transfusion in anti-HCV-positive and -negative, non-A, non-B hepatitis following surgery, patients receiving homologous blood, autologous blood alone, or no transfusions were prospectively studied. Consumption of potentially hepatotoxic drugs was also quantified. Anti-HCV antibodies were tested retrospectively when commercial assays became available. Of the 181 patients who received homologous blood which tested negative for surrogate markers of infectivity, 19 (10.5%) developed non-A, non-B hepatitis, associated with anti-HCV seroconversion in three cases. Of the 90 autologous blood recipients, non-A, non-B hepatitis developed in one (1.1%), who did not seroconvert to anti-HCV. Of the 64 untransfused patients, non-A, non-B hepatitis developed in one (1.6%), who was anti-HCV-positive before surgery. Logistic regression analysis showed that the occurrence of non-A, non-B hepatitis was associated with homologous blood transfusion, but not with the consumption of potentially hepatotoxic drugs. The 16 homologous-blood recipients who developed anti-HCV-negative, non-A, non-B hepatitis had received blood from 70 donors, none of whom had detectable anti-HCV antibodies but six of whom had minimal elevations of serum aminotransferase activity. Anti-HCV-negative, non-A, non-B hepatitis is mainly transfusion-transmitted in the surgical setting. Known hepatotropic agents may be involved despite the absence of usual serum markers, but our results are also consistent with the involvement of an unidentified non-A, non-B, non-C agent.

Adult↗
PubMed1993

Post-transfusional anti-HCV-negative non-A non-B hepatitis (II) serological and polymerase chain reaction analysis for hepatitis C and hepatitis B viruses.

Hepatitis C virus (HCV) is a major etilogical agent of post-transfusional and sporadic acute and chronic hepatitis in various geographical areas. However, anti-HCV seroconversion was uncommon in a recent study of patients with post-transfusional hepatitis in Paris, France (N. Asar et al., companion paper). The aim of the present study was to detect viral markers, in particular HCV RNA and hepatitis B virus (HBV) DNA, in these patients. A combination of second-generation assays for anti-HCV antibodies and the polymerase chain reaction were used to identify HCV RNA and HBV DNA sequences in serum samples collected before and after transfusion from patients who developed non-A, non-B hepatitis. Eighteen cases of acute, post-transfusional, non-A, non-B hepatitis were identified in the prospective clinical survey. Only three of these 18 subjects developed anti-HCV antibodies in second-generation tests. HCV RNA was identified in the serum of these three subjects but in none of the others. Two patients who were anti-HCV-negative had polymerase chain reaction evidence of HBV DNA. Known viral markers were not identified in 13 of the 18 patients with acute post-transfusional non-A, non-B hepatitis. These results raise the issue of HCV strains or 'non-A, non-B, non-C' viruses not identified by current HCV and HBV markers and implicated in post-transfusional hepatitis in France.

Base Sequence↗
PubMed1991

[Investigation of a transfusion contaminated by HTLV-I virus].

In front of the successive development of an HTLV-I seroconversion and a neuromyelopathy in a French Caucasian following a cardiac transplantation, an ascendant epidemiologic investigation must be manage to search a risk factor or a possible blood donor contaminated with HTLV-I virus. We selected an HTLV-I seropositive donor whose RBC participated to the patient's transfusion. This woman from Martinique island was a regular donor in our blood center and a second investigation was initiated to examine the patients transfused with the blood products issued from her previous donation. Nine were identified and controlled among them a patient who has received a RBC was found HTLV-I seropositive. An evaluation of the infectivity of the different blood products according to their type and specificity has been done. These data confirm that transmission of the HTLV-I is possible through donation of healthy seropositive donor and can induce the development of associated pathology, and prove the importance of screening blood donors for HTLV-I antibodies.

Adult↗