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Biomedical subjects

H Khiri

Publications and source records attributed to H Khiri.

27 records · Page 2Linked to original sources
PubMed1997

Cloning and initial characterization of human and mouse Spot 14 genes.

The intricate regulation of Spot 14 expression in rat lipogenic tissues has provided a useful tool in studying nutritional and hormonal factors involved in transcription. To gain insight into its function and its possible involvement in human lipid disorders, we cloned human and mouse Spot 14 genes that shared with the rat gene a strong homology concerning the deduced amino acid sequence (81 and 94%, respectively) as well as the promoter region. The mouse promoter was characterized by transfection studies, while quantitative RT-PCR and in situ hybridization experiments showed that Spot 14 is expressed in human liver and, at a high level, in multiple symmetric lipomatosis nodules.

Amino Acid Sequence↗
PubMed1997

Serotyping and genotyping of hepatitis C virus (HCV) strains in chronic HCV infection. Commission Hepatologie du CREGG. Club de Reflexion des Cabinets de Groupes en GastroEnterologie.

Hepatitis C virus (HCV) genotypes can be established by methods based on PCR typing and serological typing. The accuracy of these methods depends on their sensitivity and specificity. These should be compared with the reference method, direct sequencing, and analysis of viral genomes. Among the serologic methods recently developed, the performance of a new serotyping assay (RIBA HCV 3.0 SIA, Chiron corporation, Emeryville) was assessed using a panel of 147 well-characterized French isolates from chronic hepatitis C patients. Definitive genotypes of the isolates were established by direct sequencing in 5' NC and in some cases in NS-5B. HCV serotypes 1, 2, and 3 were determined by measuring type specific antibodies to core and NS-4 derived peptide antigens. Of the 147 sera, serotypic-specific antibodies were detected in 136 (sensitivity, 92.5%). The specificity of the RIBA SIA HCV serotyping assay was 92.6% (including samples with mixed results); without these, the specificity was 80.1%. Analysis of the 28 discrepant samples showed that (1) a different serotype was found in 18 samples including five for genotype 1, three for genotype 2, two for genotype 3, five for genotype 4, and three for genotype 5, and that (2) ten patients showed a reactivity with mixed serotypes, one had circulating antibodies to type 1 or 2, and nine had circulating antibodies to type 1 or 3. In summary, except for genotypes 4 and 5, the results of the test were well correlated (85.7%) with those of direct sequence genotyping. The former test is rapid and does not require the strict HCV RNA storage and preservation conditions of the latter. This new method may thus be considered as an alternative for HCV typing. However, although it is convenient, its lower sensitivity compared to the molecular typing method and the discrepant results limit its routine use in a clinical context.

Antibodies, Viral↗
PubMed1996

Quantitative multistandard RT-PCR assay using interspecies polymorphism.

The use of RT-PCR to quantify mRNA is often compromised by the variability of reverse-transcription and amplification reactions as well as by the difficulty of assessing the amount and/or the integrity of input RNA. Use of a competitor RNA or the coamplification of an endogenous standard are widespread methods of monitoring these steps. Taking advantage of both sequence conservation between homologous genes in related animal species and interspecific polymorphism, a protocol that may be regarded as a compromise between these two methods is described here. Total RNA samples, extracted from even minute amounts of tissue belonging to a first animal species, were supplemented with a constant amount of total RNA prepared from a second animal species, which thus acts as a multistandard source. The mixture was reverse-transcribed using hexa-random primers. Separate PCRs were then undertaken so that, for each mRNA of interest, products from both origins could be distinguished. Since the ratio between amplified mRNAs is constant in the standard preparation, an accurate normalization in the assay samples of most variations inherent to PCR is obtained. This protocol allows quantification of several mRNAs species, whose amounts may be very different, in a single cDNA preparation.

Actins↗
PubMed1996

Impact of various handling and storage conditions on quantitative detection of hepatitis C virus RNA.

BACKGROUND/AIMS: Both HCV RNA viral load and HCV genotype have been described as important predicting factors determining the response to interferon in chronic hepatitis C. To investigate whether processing and storage conditions might influence the stability and could alter the concentration of the HCV RNA in serum, quantification of HCV RNA was performed by branched DNA assay. METHODS: We studied serum samples obtained from seven patients with histologically proven chronic hepatitis C. These were subjected to the following physical conditions: (1) immediate quantification, (2) storage at room temperature for 5 days, (3) storage at 4 degrees C for 5 days, (4) storage at -20 degrees C for 5 days, (5) storage at -80 degrees C for 5 days, (6) five freeze-thaw cycles, (7) blood unspun for 4 h at room temperature then centrifuged and stored at -80 degrees C for 5 days, (8) storage at 4 degrees C for 6 months, (9) storage at -20 degrees C for 6 months, (10) storage at -80 degrees C for 6 months. RESULTS: A loss of 100% HCV RNA titers was observed after storage at RT for 5 days and then storage at 4 degrees C for 6 months. A surprising decrease of HCV RNA titer (15.6%) was observed in sera stored for 5 days at -20 degrees C. Five freeze-thaw cycles resulted in a 16% decrease of the HCV RNA level. When centrifugation was performed after a 4 h delay at room temperature, a significant loss of HCV RNA titers of 29.5% was observed. Long-term stability (6 months) was observed at -80 degrees C with a slight loss of about of 10% HCV RNA titers, but a significant decrease in HCV RNA of 23% was observed at -20 degrees C. The reproducibility of the bDNA assay on five patient samples was performed eight times in duplicate and showed an average coefficient of variation of 9.1%. CONCLUSIONS: These data confirm the importance of storage and handling in measuring the amount of HCV RNA in clinical samples.

Blood Preservation↗
PubMed1996

Myasthenia gravis and hepatitis C virus infection.

Chronic hepatitis C virus (HCV) infections are often associated with extrahepatic immunological manifestations, including various autoimmune disorders. The aims of this study were to determine the prevalence of HCV markers in patients with myasthenia gravis (MG) and to determine any relationship with HCV infection. Eighty-three patients with MG. 40 men aged 20-93 years and 43 women aged 13-87 years (mean age 54 years) were studied. The MG patients were positive for antibody to acetylcholine receptor in addition, their sera was analysed for antibody to HCV (HCVAb) and HCV RNA, HCVAb was detected in two of the 83 patients (2.4%). Four patients were repeatedly HCV RNA positive. They were infected by HCV genotype 1 (one patient), HCV genotype 2a (two patients) and an undetermined HCV genotype in one patient. They received plasmapheresis or intravenous immunoglobulin treatment. Among the four patients, one was infected after the onset of MG without receiving a blood transfusion or using intravenous drugs. The other three had chronic hepatitis C which was discovered at the same time as MG and only one patient had been exposed to blood products. The prevalence of HCV markers in patients with MG (4.8%) was higher than that reported for the general French population, about 1%. This prevalence is similar to that occurring in patients exposed to plasmapheresis or intravenous immunoglobulin. In conclusion, HCV appears to play little, if any, role in causing MG. The higher prevalence of infection among MG patients may be related to transmission in the course of therapy.

Adolescent↗
PubMed1995

[Risk of transmission of hepatitis C virus by digestive endoscopy].

OBJECTIVE: In 30 to 50% of cases, the route of transmission of virus C remains unknown. The aim of this study was to investigate the effectiveness of manual cleaning and disinfection procedures after endoscopic examinations in highly infected patients. METHODS: In 39 patients with chronic hepatitis C and a high level of replication, a gastroscopy with biopsy was performed with a fully submersible endoscope. Cleaning and disinfection were carried out with the following protocol: cleaning with detergent solution (Sekulyse), rinsing, 3 to 5 min immersion into a glutaraldehyde disinfectant solution (Sekucid) and final rinsing. One hundred mL of sterile water was flushed through the biopsy channel immediately after removal of the endoscope (T1), after cleaning (T2), and after final disinfection (T3). These 100 mL were collected in aliquots for viral and bacterial screening. Virus C particles were searched for in the effluent of the biopsy channel using two methods of polymerase chain reaction. RESULTS: Virus C particles were found in 2 of 39 patients in T1 aliquots collected before washing. Routine cleaning with a detergent eliminated all viral particles, as tests were negative at T2 and T3. The usual bacteria (Pseudomonas, Streptococcus, Neisseria...) were detected at T1 and had disappeared after total disinfection at T3. CONCLUSION: Virus C hepatitis could be transmitted during endoscopic examination, but cleaning and disinfection procedures effectively eliminated all viral particles.

Disinfection↗