摘要:

ObjectivesThe predictive value of positively charged amino acids at positions 11 and 25 within the V3 loop region of the human immunodeficiency virus type 1 (HIV-1) envelope gene for the syncytium-inducing (SI) phenotype was assessed.Study Design/MethodsSequencing was performed on DNA extracted from primary peripheral blood mononuclear cells (PBMCs) and complementary DNA (cDNA) prepared from serial viral isolates from 10 HIV-1–seropositive subjects. Proviral DNA sequencing was also performed on biologic clones from most of these subjects.ResultsPositive charge at position 11 and/or 25 in 257 isolate cDNA, PBMC DNA, and biologic clone PBMC DNA sequences was compared with 69 phenotypic determinations, of which 62.3% were SI. V3 genotype was 51.2% sensitive and 85.8% specific for the SI phenotype, with positive and negative predictive values of 62.8% and 79.0%, respectively. Cellular tropism failed to correlate with V3 genotype, coreceptor use, or biologic phenotype. Exclusive use of CCR5 was associated with the nonsyncytium-inducing (NSI) phenotype. Overall, V3 loop charge was higher in SI than in NSI isolates (5.01 and 3.78, respectively;p= 0.0211).ConclusionsThe predictive power of SI phenotype from V3 genotype is relatively weak, especially in a low SI prevalence population. The direct measurement of viral phenotype, cellular tropism, and coreceptor use in HIV-1 isolates is essential for accurate biologic characterization.

ISSN:1090-9508    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

IntroductionHuman immunodeficiency virus type 1 (HIV-1), HIV-2, and simian immunodeficiency virus all use chemokine receptors (CCR5, CXCR4, and minor receptors) to gain entry into a susceptible cell and establish infection successfully by way of membrane fusion. Many such chemokine receptors that can act as entry cofactors under in vitro conditions have been identified, but the roles of CCR5 and CXCR4 chemokine receptors in infection, tropism, and pathogenesis have been studied in greater detail. The promoter region of CCR5 gene is quite polymorphic in humans, and mutations that affect the progression of HIV-1 have been identified.Study Design/MethodsWe studied the nature of mutations in the CCR5 promoter region in rabbits. Large number of mutations, deletions, substitutions, and point mutations were observed all along the 400 base pair region of the promoter.ResultsWe show that rabbit CCR5 promoter possesses features common to both humans and monkeys and lacks the second highly polymorphic region B in the CCR5 promoter that was previously identified in monkeys. Besides providing important evolutionary information, our findings can directly make an impact on the known expression levels of CCR5 protein that can modulate the progression of HIV-1 in rabbits. The CXCR4 promoter of monkeys showed polymorphisms that were largely caused by single nucleotide changes when compared with humans.ConclusionsThis distinctly different evolutionary pattern suggests a more important role for chemokine receptor-CCR5 in the host defense.

ISSN:1090-9508    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectivesThe impact of intrahepatic messenger RNA (mRNA) levels of interferon &ggr; (IFN-&ggr;) and tumor necrosis factor &agr; (TNF-&agr;) on the outcome of antiviral treatment of chronic hepatitis C was evaluated.MethodsSemiquantitative mRNA determination was performed on 36 pretreatment liver biopsies by reverse transcription/competitive polymerase chain reaction.ResultsSustained response (normal aminotransferase levels and negative hepatitis C virus [HCV] RNA for more than 6 months) was achieved in 13 patients, whereas 23 of 36 patients did not achieve sustained response (12 partial responders, 11 complete nonresponders). In sustained responders, pretreatment intrahepatic mRNA levels of IFN-&ggr; and TNF-&agr; were lower than in nonsustained responders (IFN-&ggr;, 0.23 ± 0.10 vs. 0.35 ± 0.07, respectively;p= 0.024 and TNF-&agr;, 1.2 ± 0.7 vs. 2.3 ± 1.4, respectively;p= 0.009); similarly, HCV viral load was lower in sustained responders than in nonresponders (663,424 ± 756,389 copies/mL vs. 1,656,713 ± 1,517,683 copies/mL, respectively;p= 0.037). In addition, TNF-&agr; mRNA levels were correlated to HCV viral load and liver fibrosis scores.ConclusionsHigher intrahepatic mRNA levels of IFN-&ggr; and TNF-&agr; may reflect interferon resistance of HCV strains and may contribute to tissue damage in patients refractory to antiviral treatment.

ISSN:1090-9508    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectivesTo study the factors that determine malignant B cell growth in human immunodeficiency virus type 1 (HIV-1)–infected patients.Study DesignB-cell lines (lymphocyte cell lines [LCL]) were developed after nonstimulated culture of peripheral blood mononuclear cells (PBMC) from HIV-1–positive (HIV-1+) patients. Human immunodeficiency virus type 1 replication in culture, Epstein–Barr virus (EBV) latent oncogene expression, and cell-to-cell interaction were studied after nonstimulated culture of HIV-1+PBMC, analyzing their contribution to LCL appearance.MethodsNonstimulated PBMC cultures of HIV-1+PBMC and controls (N-PBMC) were established. Lymphocyte cell lines were characterized. Epstein–Barr virus latent membrane protein 1 (LMP-1) and Epstein–Barr nuclear antigen 2 were detected by polymerase chain reaction (PCR). Clonality of LCL was determined by light chain restriction (flow cytometry) and immunoglobulin H chain rearrangement (semi-nested PCR). Peripheral blood mononuclear cell phenotypes were studied at different intervals of culture.ResultsLymphocyte cell lines were obtained in 73% of HIV-1+PBMC cultures, compared with 6% in N-PBMC. All LCL were EBV-positive (EBV+). B-cell lineage was established, and up to 12 different B-cell clones were expanded from the same individual. Occurrence of LCL was more frequent in cultures with HIV-1 replication, high LMP-1 expression in viable B cells, and high CD4:CD8 ratio. Human immunodeficiency virus type 1 replication persisted in 53% of the LCL.ConclusionsIn vitro HIV-1 replication and persistence of viable EBV+lymphoblasts favor spontaneous in vitro outgrowth of LCL in HIV-1+patients.

ISSN:1090-9508    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectivesTo determine the impact of genotypic resistance testing on physician selection of antiretroviral therapy.Study Design/MethodsThis was a prospective, observational study. A single genotypic resistance test was done when patients failed highly active antiretroviral therapy. The antiretroviral regimen predicted at the time the genotypic resistance assay was done was compared with the regimen that was ultimately selected after review of resistance testing results.ResultsIn the vast majority of cases (83%), the regimen that the physician selected after resistance testing was different from the predicted regimen. In 54% of cases, these changes involved changing more than two antiretroviral agents, and in 22%, one agent was changed. In 1% of cases, all medications were discontinued, and in 6%, the physician ultimately decided not to change the baseline regimen. Although patients were screened for nonadherence to their medication regimen, 11% had no detectable resistance mutations.ConclusionsAccess to genotypic resistance testing has a significant impact on physician selection of antiretroviral therapy.

ISSN:1090-9508    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveThe type and frequency of mutations in the human immunodeficiency virus type 1 (HIV-1) reverse transcriptase coding region observed in virus from antiretroviral therapy (ART)-experienced, zidovudine (ZDV)-naive subjects receiving stavudine (d4T)-based therapies were compared with mutations observed in virus from ART-experienced subjects with previous ZDV exposure.MethodsPlasma HIV-1 RNA was isolated from 67 ART-experienced subjects. Reverse transcriptase mutations were assessed by sequencing polymerase chain reaction products.ResultsThirty-four subjects (51%) were ZDV-experienced (Zexp) and 33 (49%) were ZDV-naive and d4T-experienced (dexpZnaive). Human immunodeficiency virus type 1 from 16 of 33 (48%) dexpZnaivesubjects and from 16 of 34 (47%) Zexpsubjects had thymidine analog mutations (TAMs). Multi-nucleoside resistance (MNR) mutations were observed in virus from 5 of 33 (15%) dexpZnaivesubjects and 3 of 34 (9%) Zexpsubjects. At least one TAM or MNR mutation was identified in 18 of 33 (55%) of the former and in 19 of 34 (56%) of the latter group.ConclusionsThese results confirm recent reports that TAMs and MNR mutations can arise in subjects receiving d4T-based therapy who are naive with respect to ZDV.

ISSN:1090-9508    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveUnlike bacterial infections, herpes simplex virus (HSV) infections are rarely considered as the diagnosis in neonates less than 1 month of age who present with fever alone. We wanted to determine the proportion of neonates with HSV who presented with fever alone and to compare that with the proportion of neonates with bacterial infection who presented with fever alone over the same period of time at our institution.Study Design/MethodsWe retrospectively reviewed all neonatal medical records from March 1995 to February 1997 with a discharge diagnosis of HSV infection and all laboratory reports of a positive assay for HSV. We reviewed the medical records of neonates with a discharge diagnosis of bacterial infection over the same period of time. We excluded neonates who were afebrile, whose fever source was evident on physical examination, or who were immunocompromised.ResultsEighteen neonates were diagnosed with an HSV infection over the 2-year period. One presented with fever alone. Twenty-seven of 113 neonates who presented with fever alone had a bacterial infection; 2 of these babies had meningitis.ConclusionThe proportion of neonates with HSV infection who presented with fever alone was comparable to that of neonates with bacterial meningitis who presented with fever alone at our institution. Testing and empirically treating for HSV infection might be warranted in febrile neonates with negative bacterial cultures.

ISSN:1090-9508    

出版商:OVID    

年代:2001

数据来源: OVID