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Biomedical subjects

J Duval

Publications and source records attributed to J Duval.

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

Development of fluoroquinolone resistance in Enterococcus faecalis and role of mutations in the DNA gyrase gyrA gene.

We have analyzed the development of fluoroquinolone resistance between 1986 and 1993 among clinical isolates of Enterococcus faecalis from a French hospital. One hundred randomly selected isolates per year were screened for resistance to ciprofloxacin (MIC > 2 micrograms/ml) and for high-level resistance to gentamicin (MIC > 1,000 micrograms/ml). The percentages of ciprofloxacin-resistant strains for these years were as follows: 1986, 0; 1987, 1; 1988 to 1989, 2; 1990, 6; 1991, 16; 1992, 24; and 1993, 14. Eighty-three percent of the ciprofloxacin-resistant isolates were coresistant to high levels of gentamicin. Forty-eight high-level gentamicin-resistant E. faecalis strains, which were resistant (24 strains) or susceptible (24 strains) to ciprofloxacin, were examined by pulsed-field gel electrophoresis (PFGE) of SmaI-digested total DNA. Numerous PFGE types were observed among the ciprofloxacin-susceptible isolates, whereas one type was largely predominant among the ciprofloxacin-resistant strains, which suggests that the increase in fluoroquinolone resistance was due to the spread of a single clone. A 241-bp fragment of gyrA, corresponding to the quinolone resistance-determining region, was amplified and sequenced for seven ciprofloxacin-resistant isolates. Six strains had high levels of resistance (MICs, 32 to 64 micrograms/ml) and had a mutation at position 83 (Escherichia coli coordinates) from Ser to Arg (three strains) or to Ile (two strains) or at position 87 from Glu to Gly (one strain), whereas the low-level-resistant isolate (MIC, 8 micrograms/ml) had no mutations.

Anti-Infective Agents↗
PubMed1996

Effect of alpha interferon (IFN-alpha) on 2'-5' oligoadenylate synthetase activity in peripheral blood mononuclear cells of patients with chronic hepatitis C: relationship to the antiviral effect of IFN-alpha.

Alpha interferon (IFN-alpha) is, to date, the only treatment with proven efficacy in patients with chronic hepatitis C. However, less than 15% of the patients have a sustained response to IFN-alpha. Interferon acts through the induction of various cellular enzymes. Among them, the 2'-5' oligoadenylate synthetase (2-5OAS) is (at least in part) responsible for a direct antiviral effect of IFN-alpha. The aim of this study was to determine whether basal and IFN-alpha-induced in vivo and in vitro 2-5OAS activities measured in peripheral blood mononuclear cells predict biochemical and virological responses to IFN-alpha in patients with chronic hepatitis C. 2-5OAS activity in peripheral blood mononuclear cells and the antiviral effect of IFN-alpha were studied in 36 patients with chronic hepatitis C (27 men and 9 women; mean age, 44.7 years). Basal in vivo 2-5OAS activity (mean +/- standard error of the mean) was 4.41 +/- 0.69 nmol/10(6) cells. It was significantly induced at month 3 of IFN-alpha therapy (18.07 +/- 2.74 nmol/10(6) cells; P = 0.0001). No significant differences were found in basal in vivo 2-5OAS activities, in IFN-alpha-induced/basal in vitro 2-5OAS activity ratios, in IFN-alpha-induced in vivo 2-5OAS activities, and in IFN-alpha-induced/basal in vivo 2-5OAS activity ratios between the patients with and without a biochemical response (normal alanine aminotransferase activity in serum) or a virological response (normal alanine aminotransferase activity in serum and negative hepatitis C virus RNA detection) at any step of the study. At month 3 of therapy, p69, which is considered to be the active isoform of 2-5OAS, was induced, as demonstrated by Western blot (immunoblot) analysis in 50% of the patients, and induction of the p100 isoform was observed in 70% of the patients. No significant relationship with the response to IFN-alpha therapy was observed. Our results suggest that a deficiency of the IFN-alpha-dependent 2-5OAS system, which could be genetically determined, is unlikely to be responsible for the failure to achieve biochemical and virological responses to IFN-alpha therapy in patients with chronic hepatitis C.

2',5'-Oligoadenylate Synthetase↗
PubMed1996

Significance of indeterminate third-generation hepatitis C virus recombinant immunoblot assay.

Indeterminate hepatitis C virus (HCV) third-generation recombinant immunoblot assay (RIBA3.0; Ortho Diagnostic Systems) patterns were arbitrarily defined by the manufacturer as the detection of only one antibody out of the four that were sought, namely, c100 (NS4 encoded), c22 (core encoded), c33c (NS3 encoded), and NS5 (NS5 encoded). The aims of the present study were (i) to determine the prevalence of indeterminate RIBA3.0 patterns in patients consecutively tested for anti-HCV antibodies in a university hospital; (ii) to evaluate the significance of these patterns in terms of viral replication, liver disease, and risk factors for HCV; and (iii) to get an insight into the mechanism underlying this peculiar immune response. Among 3,074 serum samples consecutively tested for anti-HCV antibodies, 588 were found to be positive by screening assays. Fifty-nine of them (10%) were RIBA3.0 indeterminate and were compared with 59 RIBA3.0-positive ones. Thirty-one RIBA3.0-indeterminate and 53 RIBA3.0-positive serum samples were HCV RNA positive by PCR (53 versus 90%; P < 10(-6). RIBA3.0-indeterminate and RIBA-3.0-positive patients with positive PCR results were not significantly different for the prevalence of risk factors for HCV infection and elevated serum alanine aminotransferase activities. Immunosuppression, attributable to coexisting human immunodeficiency virus infection, organ transplantation, or the administration of immunosuppressive drugs, was significantly more frequent in PCR-positive, RIBA3.0-indeterminate patients than in PCR-negative, RIBA3.0 indeterminate patients (P < 0.001) and PCR-positive patients with a positive RIBA3.0 result (P < 0.01). The distribution of HCV genotypes did not differ significantly between HCV RNA-positive patients with indeterminate or positive RIBA3.0 results. In conclusion, the prevalence of indeterminate RIBA3.0 patterns in virology laboratories is about 10%; in about half of these patients HCV replication is detected by PCR; the main factor responsible for indeterminate RIBA3.0 patterns could be immunosuppression, whereas HCV genotypes do not seem to play major role.

Antigens, Viral↗
PubMed1996

Molecular cloning of a hemopexin-like cDNA from rainbow trout liver.

Hemopexin is an abundant heme-binding serum protein synthesized in the liver and for which the sequence is determined only for mammals. Little is known about fish heme-binding proteins. We have cloned a rainbow trout complementary DNA that encodes a 445 amino acid polypeptide exhibiting an overall 30% homology with human hemopexin and 69% with the goldfish warm temperature acclimation-related 65-kDa protein. Structural homology, deduced from hydrophobic cluster analysis (HCA), was strong between the trout and human proteins since global HCA scores of 76% were obtained when the N- or C-terminal halves of the two proteins were compared. Moreover, several characteristics of hemopexin were found in the trout protein; finally, the trout hemopexin-like messenger RNA was specifically expressed in the liver. We conclude that the trout protein is a good candidate for a true fish hemopexin.

Amino Acid Sequence↗
PubMed1995

Serial quantitative determination of hepatitis C virus RNA levels after liver transplantation. A useful test for diagnosis of hepatitis C virus reinfection.

After liver transplantation for hepatitis C virus (HCV)-related cirrhosis, recurrent viral infection is almost constant, resulting in acute graft dysfunction in 30-75% of cases. Acute graft dysfunction in the post-transplant period may also be the result of various causes (such as rejection, CMV infection, sepsis, or technical problems). Therefore, the role of HCV reinfection is often difficult to document. The aim of this study was to assess the diagnostic value of serial HCV RNA quantitation in this setting. Fourteen patients transplanted with follow-up greater than 6 months were studied. HCV RNA was quantitated before and serially after transplantation, using branched DNA technology. In cases of acute graft dysfunction, usual investigations and additional HCV RNA quantitation were conducted. There were 15 episodes of acute graft dysfunction in 12 patients. Six episodes had a hepatitic biochemical pattern, and 5 of them were associated with a concomitant HCV RNA peak. Nine episodes had a mixed, hepatitic, and cholestatic biochemical pattern, and 5 of them were associated with a concomitant peak of HCV RNA. Overall, 10 of 15 (66%) episodes of acute graft dysfunction were associated with HCV RNA peak, which strongly suggests that HCV was the etiologic factor. In 9 of these 10 episodes, no other cause of dysfunction was found, and one had associated CMV disease. In 5 cases, no peak of HCV RNA was observed and the causes of dysfunction were CMV (in 2 cases) and rejection, granulomatosis, and unknown (in 1 case each). Serial quantitations of HCV RNA levels after liver transplantation for cirrhosis C provide a useful tool in the diagnosis of HCV reinfection of the graft.

Adult↗
PubMed1995

Extrahepatic immunologic manifestations in chronic hepatitis C and hepatitis C virus serotypes.

OBJECTIVE: To determine, using a serotyping assay, whether the occurrence of extrahepatic immunologic disorders in patients with chronic hepatitis C is dependent on hepatitis C virus serotype. DESIGN: Prospective study. SETTING: Liver unit and virology laboratory of a university hospital. PATIENTS: 59 consecutive patients with chronic hepatitis C. MEASUREMENTS: Hepatitis C virus serotype was determined using a recently developed immunoenzymatic assay that detects antibodies directed to serotype-specific immunodominant epitopes. Cryoglobulin, rheumatoid factor, and numerous antitissue antibodies were sought. Biopsies of labial salivary glands were done in 49 of the 59 patients. RESULTS: Prevalence was 59% for serotype 1, 10% for serotype 2, 12% for serotype 3, and 3% for mixed infection. Fifteen percent of patients could not be serotyped. Cryoglobulinemia was found in 36% of patients and rheumatoid factor was found in the serum of 71%. At least one antitissue antibody was found in the serum of 41% of patients; salivary gland biopsy showed lymphocytic capillaritis in 49% of patients. These immunologic abnormalities were seen in patients infected with any of the three serotypes, and prevalences of the abnormalities did not differ significantly among patients infected with different serotypes. CONCLUSIONS: We confirm that the prevalence of extrahepatic immunologic abnormalities is high in patients with chronic hepatitis C. These abnormalities may occur in patients infected with any of the three major hepatitis C virus serotypes now present in developed countries.

Adolescent↗
PubMed1995

Is the detection of anti-hepatitis C virus core IgM influenced by the presence of serum rheumatoid factor?

Rheumatoid factor (RF) induces false-positive results in the detection of serum antibodies, especially of the IgM type. About 70% of the patients with chronic hepatitis C have abnormal levels of serum RF. The aim of this study was to determine whether the presence of serum RF could influence the detection of anti-HCV core IgM, using an assay designed not to pick up RFs by the addition of goat antibodies directed against human IgG in the sample diluent. Serum anti-HCV core IgM antibodies and RF were sought in 60 patients with chronic hepatitis C. Serum anti-HCV IgG antibodies and anti-HCV core IgM antibodies were also sought in 101 patients with high levels of RF. Anti-HCV core IgM antibodies were found in 45% and serum RF in 72% of the patients with chronic hepatitis C. Neither the prevalence nor the levels of RF differed significantly between IgM positive and negative patients. Eight percent of the 101 patients with raised RF had anti-HCV antibodies and two of them had anti-HCV core IgM antibodies. No patient without anti-HCV antibodies had anti-HCV core IgM antibodies. These results show that: a) the detection of anti-HCV core IgM in patients with chronic hepatitis C is independent of the presence of serum RF; b) high titers of serum RF are not responsible for false-positive results of anti-HCV IgM tests. The study suggests that the test used could be a confident tool for studies on the significance of anti-HCV core IgM antibodies in chronic hepatitis C.

Chronic Disease↗
PubMed1995

High prevalence of hepatitis B, C, and E markers in young sexually active adults from the Central African Republic.

The Central African Republic is located in tropical Africa, where both the human immunodeficiency virus (HIV) and hepatitis B virus (HBV) are highly endemic. The exact prevalence of hepatitis C virus (HCV) and hepatitis E virus (HEV) markers in this country is unknown. The aim of the study was to determine, according to HIV and HBV serostatus, the prevalence of these markers in young sexually active adults in the Central African Republic. One hundred and fifty-seven consecutive patients attending the National Centre for Sexually Transmitted Diseases in Bangui were included. The following serological markers were examined: (i) anti-HIV1 and anti-HIV2 antibodies; (ii) markers of HBV infection; (iii) anti-HCV antibodies; (iv) anti-HEV antibodies. Anti-HIV1 antibodies were found in 31 of the 157 patients (20%). The prevalence of anti-HBc antibodies, reflecting exposure to HBV, was 140/157 (89%) and 45 had detectable anti-HBs antibodies. Twenty-two patients (14%) were chronic carriers of hepatitis B surface antigen (HBsAg), but only one was HBe antigen-positive. Anti-HCV antibodies were found in 8 persons (5%) and anti-HEV antibodies in 38 (24%). No difference was found in the prevalence of these markers according to the presence or absence of anti-HIV antibodies. This study confirms the high rate of HIV infection, HBV exposure and chronic carriage of HBsAg in sexually active young adults in the Central African Republic. A high prevalence of HCV markers was found in this population, similar to that reported in neighbouring countries, together with a high rate of HEV markers, suggesting that HEV is endemic in this region.

Adolescent↗
PubMed1995

Hepatitis C virus infection and autoimmune thrombocytopenic purpura.

BACKGROUND/AIMS: Chronic hepatitis C virus infections are often associated with extra-hepatic immunological manifestations, including various autoimmune disorders. The aims of this study were: (i) to determine the prevalence of hepatitis C virus markers in patients with autoimmune thrombocytopenic purpura, and (ii) to determine whether a relationship could exist between autoimmune thrombocytopenic purpura and hepatitis C virus infections. METHODS: One hundred and thirty-nine patients with autoimmune thrombocytopenic purpura (45 men, 94 women, mean age 42 years, range 16-90) were studied. RESULTS: Anti-HCV antibodies were sought in their first and last available cryopreserved sera. In case of seropositivity, all their available cryopreserved sera were tested for anti-HCV antibodies and for HCV-RNA. Anti-HCV antibodies were detected in 14 of the 139 patients (10%). Four patients had transient anti-HCV seropositivity due to passive transfer of anti-HCV antibodies secondary to the infusion of intravenous immunoglobulin concentrates. Three patients seroconverted during follow up, due to intravenous drug use in one case, transfusion of non-HCV-screened blood units in one case, and infusion of intravenous immunoglobulins in one case. Seven patients had chronic hepatitis C discovered at the same time as autoimmune thrombocytopenic purpura. In two of them, hepatitis C virus transmission was the consequence of autoimmune thrombocytopenic purpura treatment but, in five cases, hepatitis C virus infection predated autoimmune thrombocytopenic purpura, so that the role of hepatitis C virus in autoimmune thrombocytopenic purpura could be suggested. CONCLUSIONS: Whereas hepatitis C virus does not appear to be the main etiological agent of autoimmune thrombocytopenic purpura can be envisaged. On the other hand, treatment of autoimmune thrombocytopenic purpura or autoimmune thrombocytopenic purpura-related symptoms by blood product infusion can be complicated by hepatitis C virus transmission.

Adolescent↗
PubMed1995

Evolution of bacterial susceptibility to antibiotics during a six-year period in a haematology unit.

A knowledge of the bacterial ecology of a haematology unit should help in the management of the febrile patient with or without neutropenia. We studied the prevalence and the susceptibility profiles of bacteria isolated during a six-year period among patients hospitalized in a 44-bed haematology unit. Antibiotic use over this period was also studied. The most prevalent bacteria were coagulase-negative staphylococci (CNS) (35.1%), Escherichia coli (11.4%), Staphylococcus aureus (9.9%), Enterococcus spp. (8.2%), and Pseudomonas aeruginosa (7.5%). The susceptibility of CNS to oxacillin decreased from 67-44% over six years, while that of enterobacteriaceae to amoxycillin and piperacillin was reduced by about 50%. P. aeruginosa susceptibility to ceftazidime remained remarkably stable at around 90%, despite extensive empirical use. Imipenem and ciprofloxacin were used restrictively and ceftazidime-resistant P. aeruginosa remained susceptible to these two agents in most cases. Our antibiotic policy was found to be compatible with the frequency of the bacterial strains isolated in our department and with their susceptibility profiles.

Anti-Bacterial Agents↗
PubMed1995

Occurrence of secretogranin II in the prolactin-immunoreactive neurons of the rat lateral hypothalamus: an in situ hybridization and immunocytochemical study.

The occurrence of secretogranin II in a neuron population of the rat lateral hypothalamus specifically detected by an anti-serum to ovine prolactin was examined. As this population was previously reported to synthesize dynorphin, the distribution of neurons recognized by ovine prolactin-, dynorphin B- and secretogranin II anti-sera was investigated on adjacent sections of hypothalami. The prolactin immunoreactive neurons were the only cells in the lateral hypothalamus to be stained by secretogranin II anti-serum. Moreover, coupling immunocytochemical detection and in situ hybridization with an oligonucleotide probe complementary to secretogranin II mRNA showed that these neurons expressed the secretogranin II gene. These new findings should help to study the physiological role of the prolactin immunoreactive neurons of the lateral hypothalamus.

Animals↗
PubMed1995

Activity of the interferon-induced 2',5'-oligoadenylate synthetase in patients with chronic hepatitis C.

The interferon-induced 2',5'-oligoadenylate synthetase (2-5OAS) is responsible, at least in part, for the antiviral state established in cells in response to viral infections. The purpose of this work was to study the relationship between hepatitis C virus (HCV) infection and 2-5OAS in patients with chronic hepatitis C. Peripheral blood mononuclear cells (PBMC) of 27 patients with chronic hepatitis C were investigated, as well as PBMC of 10 control subjects. Then, the patients were treated with 3 mu interferon-alpha 2a three times per week. At month 3 of therapy, PBMC were sampled. Of the total PBMC samples obtained, half were used for determination of in vivo 2-5OAS activity. The remaining cells were cultured for 24 h in either the absence or presence of 500 U/ml of interferon-alpha 2a for the determination of in vitro 2-5OAS activity. The mean basal in vivo 2-5OAS activities were 3.6 +/- 2.8 nmol/10(6) cells in patients versus 1.6 +/- 1.1 nmol/10(6) cells in controls (p < 0.01). Basal in vivo 2-5OAS activity did not correlate with mean HCV viremia, quantified by a "branched DNA"-based assay. Before treatment, interferon-alpha was detected in the serum of 2 patients in 27. After a 24 h culture of PBMC in the presence of interferon, in vitro 2-5OAS activity was significantly induced in the PBMC of both the patients and the controls. However, in vitro induction of 2-5OAS activity was significantly lower in the PBMC of the patients than in the PBMC of the controls (p < 0.01). At month 3 therapy, in vivo 2-5OAS activity was significantly induced (20.5 +/- 17.9; p < 0.0001). In vitro IFN inductions of 2-5OAS activity in PBMC before treatment and at month 3 of therapy were not significantly different. In conclusion, in vivo 2-5OAS activity is significantly induced in patients with chronic hepatitis C, but endogenously produced interferon-alpha does not seem to be involved. Chronic induction of 2-5OAS activity results in a decreased sensitivity of PBMC to exogenous interferon induction. Whether this phenomenon plays a role in the resistance of chronic hepatitis C to interferon therapy remains uncertain.

2',5'-Oligoadenylate Synthetase↗
PubMed1995

Relationship between hepatitis C virus genotypes and sources of infection in patients with chronic hepatitis C.

This study examined the relationships between hepatitis C virus (HCV) genotypes and the routes of HCV transmission in 101 patients with chronic hepatitis C. Patients who received blood transfusions (43%) and those with chronic hepatitis C of unknown cause (37%) had similar mean ages, age distribution, and HCV genotype distribution (1a, 19% vs. 14%; 1b, 52% vs. 54%; 3a, 10% vs. 9%; other, 19% vs. 23%). Intravenous drug users (IVDUs) were significantly younger and had a different genotype distribution (1a, 33%; 1b, 0; 3a, 63%; other, 5%; P < .001). Transmission of HCV 3a has been observed only over the past 20 years; other genotypes were transmitted up to 40 years ago. These results suggest that for 20 years there have been two independent ongoing hepatitis C epidemics. One affects persons who received blood transfusions or whose source of infection is unknown. These persons are older and are mainly infected by HCV 1b. The second type of infection occurs in IVDUs and infects younger persons, mainly with HCV 3a.

Adult↗
PubMed1995

Critical influence of resistance to streptogramin B-type antibiotics on activity of RP 59500 (quinupristin-dalfopristin) in experimental endocarditis due to Staphylococcus aureus.

In order to determine the microbiological and pharmacokinetic parameters that best predicted the in vivo antistaphylococcal activity of the streptogramin RP 59500 (quinupristin-dalfopristin), we evaluated the activity in rabbit aortic endocarditis of three regimens of quinupristin-dalfopristin against five strains of Staphylococcus aureus with various streptogramin B-type antibiotic resistance phenotypes and susceptible to streptogramin A-type antibiotics. Quinupristin-dalfopristin was as active as vancomycin against three strains that were susceptible to its streptogramin B component quinupristin, including one strain that was inducibly resistant to erythromycin, but had a significantly decreased activity against two strains that were resistant to quinupristin, for all quinupristin-dalfopristin regimens tested (P < 0.05). The area under the concentration-time curve for quinupristin-dalfopristin in plasma divided by the MIC of quinupristin was the only parameter retained by multilinear regression that predicted the in vivo activity of quinupristin-dalfopristin (P = 0.0001), emphasizing the importance of determining the susceptibility to quinupristin in order to predict the in vivo activity of quinupristin-dalfopristin against S. aureus.

Animals↗