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Biomedical subjects

A Iwamoto

Publications and source records attributed to A Iwamoto.

At least 109 records · Page 6Linked to original sources
PubMed1997

CD8+ T lymphocyte counts as an adjunctive predictor of cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome.

We encountered a case of cytomegalovirus (CMV) retinitis with spontaneous regression in association with an increased number of CD8+ but not CD4+ T lymphocytes in a patient with acquired immunodeficiency syndrome (AIDS). Thus, we examined the number of CD4 and CD8 counts at the diagnosis of CMV retinitis and compared with those of Pneumocystis carinii pneumonia (PCP). All 21 patients with a confirmed diagnosis of PCP (22 episodes) and 14 CMV retinitis patients were included in this study. Although PCP occurred after depletion of CD4 count to below 200/microl, CD8 count at that time varied widely and remained normal in some patients (median: 276.5/microl, range: 133-900/microl). In contrast, as CMV retinitis occurred after further depletion of CD4 count to below 50/microl, CD8 count decreased to below 500/microl (median: 238/microl, range: 43-448/microl) (p<0.05; PCP vs CMV retinitis). The values of the sensitivity and specificity for CMV retinitis obtained at the cutoff point of either 400/microl in CD8 count and 50/microl in CD4 count were similar. When these two cutoff points were combined, the positive predictive value was 46%. Monitoring of CD8 count may prove valuable as an additional predictor of CMV retinitis in patients with AIDS after CD4 depletion.

AIDS-Related Opportunistic Infections↗
PubMed1997

Dual phasic suppression of viral replication following de novo human immunodeficiency virus type 1 (HIV-1) infection in lymphocytes of asymptomatic HIV-1 carriers.

Replication of human immunodeficiency virus type 1 (HIV-1) is suppressed in asymptomatic HIV-1 carriers (ACs). By using an in vitro experimental system, the mechanism of this suppression was investigated. Following in vitro infection of a laboratory HIV-1 strain, the peripheral blood mononuclear cells (PBMC) of ACs transiently supported a low level of viral replication, then the virus production rapidly decreased. PCR analysis revealed that HIV-1 proviral DNA integrated in the PBMC of ACs following infection gradually decreased. Such tapering consequences of in vitro HIV-1 infection in the PBMC of ACs were abrogated by depletion of CD8+ T cells from the culture. Furthermore, the viruses subsequently produced by the PBMC of an AC were less able to replicate than the virus produced by CD8+ cell-depleted PBMC of the same donor. These observations suggested that the CD8+ T cell-mediated suppression of HIV-1 replication in ACs may involve both cytocidal and cytostatic mechanisms: the former kills the cells producing viruses, and the latter inhibits viral spread by reducing viral infectivity.

CD8-Positive T-Lymphocytes↗
PubMed1996

Type of human papillomavirus is related to clinical features of cervical carcinoma.

BACKGROUND: Despite the fact that approximately ten types of human papillomavirus (HPV) are associated with cervical carcinoma, the question of whether the HPV type present in cervical carcinoma is related to clinical behavior had yet to be answered when this study was conducted. METHODS: The presence and type of HPV were determined by polymerase chain reaction (PCR)-based assay (LI-PCR) in 146 cervical carcinomas. Clinical features were compared among the following 4 groups: Group 18 (27 patients positive for HPV 18), Group 16 (55 patients positive for HPV 16), Group O (47 patients positive for the other HPV types), and Group N (17 HPV negative patients). Special focus was given to histologic type, patient's age at onset, and patient survival as indicators of the biologic properties of the carcinomas. RESULTS: Occurrence of adenocarcinoma or adenosquamous carcinoma was higher in Group 18 (48%) than in Group 16 (13%) or Group O (9%) (P < 0.0005). The mean age of the patients at onset was different among the 4 groups (Group 18, 46 years; Group 16, 55 years; Group O, 63 years; Group N, 58 years) (P < 0.005). The prevalence of HPV 18, HPV 16, and other forms of the virus was most frequent in ages < 40, 50-79, and > 60, respectively. Group 18 had a poorer prognosis than Group 16, O, or N. A statistical difference in the 5-year survival rate was found between Groups 18 and 16 (52% vs. 74%, P < 0.05). CONCLUSIONS: These data suggest that the HPV type present in cervical carcinoma is related to clinical behavior.

Adenocarcinoma↗
PubMed1996

Genomic organization of human papillomavirus type 18 in cervical cancer specimens.

It has been reported that cervical cancers positive for human papillomavirus (HPV) 18 have a poorer prognosis than those with other HPV types. To gain a better understanding of the aggressive character of HPV 18-positive cancers, we examined the difference in genomic organization between HPV 18 and HPV 16 harbored in cervical cancers. We amplified E1 and E2 genes from 9 HPV 18-positive and 31 HPV 16-positive cervical cancers by polymerase chain reaction (PCR). At least one of the two early genes was missing in 3 out of 9 HPV 18-positive cancers, while both PCRs were positive in all 31 HPV 16-positive cancers (P < 0.05). We then analyzed the 9 HPV 18-positive cancers by 15 contiguous polymerase chain reactions covering collectively the whole HPV 18 genome. In addition to the three with a deletion of the E1 or E2 gene, one had a deletion in the E5 and L2 genes and one had an insertion in the long control region. The frequent alterations in genomic organization, especially preferential deletion of the E1 or E2 gene, may be related to the more aggressive properties of HPV 18-positive cervical cancers.

Adenocarcinoma↗
PubMed1996

Association of multiple human papillomavirus types with vulvar neoplasias.

OBJECTIVE: The purpose of this study was to clarify the association of multiple genital human papillomavirus (HPV) types with vulvar neoplasias. METHODS: We examined vulvar neoplasias by the polymerase chain reaction (PCR) method, which can detect almost all genital HPV types sensitively (L1-PCR). RESULTS: Eight HPV types (types 6, 11, 16, 18, 52, 53, 56, and 68) were detected in 52 of 53 (98.1%) vulvar condylomas; 2 HPV types (types 16 and 18) were detected in all 6 Grade-3 vulvar intraepithelial neoplasias; and 5 HPV types (types 6, 16, 18, 51, and 56) were detected in 8 of 11 (72.7%) invasive vulvar carcinomas. Detection of HPV types 52, 53, 56, and 68 in vulvar condylomas and detection of HPV types 51 and 56 in vulvar carcinomas are the first examples ever reported. CONCLUSION: This study suggests that more HPV types are associated with the generation of vulvar neoplasias than was thought to be the case up to now.

Adolescent↗
PubMed1996

Possible role of splice acceptor site in expression of unspliced gag-containing message of Moloney murine leukemia virus.

Moloney murine leukemia virus (MLV) having the gag coding region alone, G3.6, produced a low level of mRNA (1/10 of the wild-type level). Ligation of 441 nucleotides (nt) containing a splice acceptor (SA) site to the downstream portion of the remaining gag region restored the level of the unspliced message, simultaneously activating a cryptic splice donor (SD) site in the middle of the p30 coding region (between nt 1596 and 1597). Ligation of the 441 nt in the same site in the inverted orientation also increased the level of the unspliced message, activating the same SD site (between nt 1596 and 1597) and a new SA site just in front of the inserted 441 nt (between nt 4770 and 4771). Deletion or inversion of the 441-nt SA sequence from the wild-type MLV or from int in-frame deletion or int frameshift mutant MLVs of nearly full size resulted in the loss of spliced mRNA and concomitantly in a severe reduction of the unspliced mRNA, particularly at 37 degrees C. Deletion of the 5' SD site did not result in the reduction of the unspliced-mRNA level. When the gag region in G3.6 was replaced with a Neo(r) coding region, the level of expression was high. The data taken together suggest that the presence of an SA signal is necessary for high-level expression of unspliced mRNA encoding Gag or Gag-Pol.

3T3 Cells↗
PubMed1996

[Intravitreal injection of ganciclovir in AIDS patients with cytomegalovirus retinitis].

The therapeutic effects and safety of intravitreal ganciclovir injection were evaluated in 16 acquired immunodeficiency syndrome (AIDS) patients with cytomegalovirus (CMV) retinitis. The induction therapy was done in a total of 23 courses, i.e., in 14 eyes of 10 patients. Active lesions of CMV retinitis were suppressed by 3 to 7 injections over 21 to 42 days after the initiation of the induction therapy. Intravitreal injections once a week for maintenance suppressed the reactivation of the lesions for at least 6 weeks in 9 eyes of 7 patients among 10 eyes of 8 patients. As for the safety of intravitreal ganciclovir injections in the 16 AIDS patients with CMV retinitis, a total of 354 injections were given and two serious complications, that is, endophthalmitis and retinal detachment were observed in one eye each. During the course of intravitreal injection, 3 of 7 patients developed CMV retinitis in the contralateral eye and systemic CMV infections were suspected in 3 of 12 patients. Intravitreal injection of ganciclovir is thought to be effective for the treatment of CMV retinitis in AIDS patients, but careful procedure and examinations are needed.

AIDS-Related Opportunistic Infections↗
PubMed1995

Selective transmission of hepatitis C virus in vivo and in vitro.

A human plasma containing quasi-species of hepatitis C virus (HCV) was inoculated to a chimpanzee and to human lymphocytic cell lines, HPB-Ma clone 10-2, AD HPB, and Daudi, which support replication of HCV. Among six different hypervariable region (HVR) sequences detected in the inoculum, the same two were recovered both in vivo and in vitro.

Amino Acid Sequence↗
PubMed1995

Targeted infection of a retrovirus bearing a CD4-Env chimera into human cells expressing human immunodeficiency virus type 1.

We constructed a hybrid Moloney murine leukaemia virus (MoMLV) bearing both a chimeric CD4 and the wild-type MoMLV envelope protein (Env) on its surface. The chimeric molecule, consisting of a surface domain of CD4 and the C-terminal two-thirds of MLV Env, was expressed on the cell surface. When expressed in MoMLV-infected cells, the CD4-Env chimera was incorporated into the virion as efficiently as the wild-type MoMLV Env. The hybrid MoMLV could infect human HeLa cells (although not with high efficiency) only if the cells were expressing human immunodeficiency virus type 1 genome. This method of ligand incorporation into a virion may lead to a development of a cell-specific retroviral vector for targeting gene therapy.

3T3 Cells↗
PubMed1995

[Comparison of amplified Mycobacterium Tuberculosis Direct Test (MTD), Amplicor Mycobacteria kit (Amplicor) and PCR method for detection Mycobacterium tuberculosis in clinical specimens].

Accuracy amplified Mycobacterium Tuberculosis Direct Test (MTD), Amplicor Mycobacteria kit (Amplicor) and PCR method routinely used in the University of Tokyo Hospital (J. Clin. Microbiol. 31: 446-450 1991) were evaluated and compared with the same samples. The detection limits of MTD, Amplicor and PCR method (University of Tokyo) were 0.01-0.1 CFU/tube, 0.625 CFU/tube and 0.2 CFU/tube respectively, which were almost the same. These were shown to be at least as sensitive as the conventional culture techniques. The Tokyo Univ. method using radioisotope, takes up to 3 days, on the other hand 2 kits take 4-5 hours. These kits become useful tools for the early and rapid detection of M. tuberculosis in uncultured clinical specimens. But the risk of laboratory contamination and false-positive results remain. These must be further improved.

Bacteriological Techniques↗
PubMed1995

[The efficacy of midazolam-famotidine suppository for premedication in children].

We evaluated the efficacy of midazolam-famotidine suppository (M-F suppository) for premedication in children. After obtaining informed parental consent, we studied children aged 5m-7y, ASA I status, scheduled for minor elective surgery. The suppository group (n = 26) was given suppository of both midazolam 0.5 mg.kg-1 and famotidine 2 mg.kg-1, and the intramuscular injection group (n = 19) was given hydroxyzine 1 mg.kg-1. In the suppository group, gastric pH (3.90 +/- 0.34) was significantly higher, and gastric volume (1.88 +/- 0.54 ml) was significantly less than in the intramuscular injection group (1.82 +/- 0.15, 8.42 +/- 1.76 ml). The M-F suppository may offer similar sedative effect as an intramuscular injection of hydroxyzine. We concluded that the M-F suppository is an effective premedicant for pediatric patients.

Administration, Rectal↗