[Antimicrobial therapy for patients with HIV infection].
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Anti-Bacterial Agents↗
Biomedical subjects
Tomohiko Koibuchi
Publications and source records attributed to Tomohiko Koibuchi.
Molecular epidemiology of hepatitis A virus in metropolitan areas in Japan.
BACKGROUND: Transmission routes of hepatitis A virus (HAV) in Japan have changed. The present study investigated changes of transmission routes in relation to genetic drift. METHODS: All 60 patients who were admitted between 1993 and 2003 with a diagnosis of hepatitis A were retrospectively analyzed. Nucleotide sequences of the VP1/2A region of the HAV recovered from their sera were determined. RESULTS: The suspected transmission routes were household contact, 19 (31%); food or waterborne, 16 (27%); homosexual activity, 11 (18%); international travel, 4 (7%); and unknown 10. (17%). The 11 patients presumably infected through homosexual activity were found exclusively in 1998 and 1999. The proportion of patients exposed through homosexual behavior and household contact was higher in those 2 years than in other years. Nucleotide sequences could be determined for 58 patients. Fifty-seven of the 58 sequences belonged to genotype IA HAV, with less than 10% nucleotide diversity. Of the 27 sequences isolated during 1998 and 1999, 25 had an identical nucleotide sequence regardless of the suspected transmission route. In contrast, sequences obtained in the other years differed from one another. A phylogenetic tree constructed from sequences recovered from patients without a history of travel abroad showed several clusters. CONCLUSIONS: Our results suggest that (1) HAV acquired through homosexual activity may be transmitted to nonhomosexual individuals; (2) hepatitis A in metropolitan areas in Japan is caused mainly by sporadic infection with genotype IA HAV; and (3) several subtypes of genotype IA HAV are endemic in Japan.
Adult↗
Questionnaire-based analysis of mefloquine chemoprophylaxis for malaria in a Japanese population.
Although mefloquine is the only drug licensed for malaria chemoprophylaxis in Japan, there have been few reports describing the effects of and adverse events in the prophylactic usage of mefloquine in a Japanese population. We therefore performed a questionnaire-based study in 21 travelers who were prescribed mefloquine for malaria chemoprophylaxis between October 2001 and December 2003. The study revealed that only 8 out of 21 (38.1%) of the travelers could complete the prophylaxis schedules. Another 8 travelers (38.1%) with incomplete adherence stated that they did not take mefloquine because of either actually experienced or anticipated adverse events. Twelve of the 16 travelers (75.0%) who took mefloquine complained of at least one adverse event probably related to mefloquine. As an overall impression about mefloquine chemoprophylaxis, 14 of the 21 travelers stated that they would take mefloquine again for the next travel to malaria-endemic areas, although 5 of them were concerned about adverse events. These results suggest that, although mefloquine is an indispensable drug for malaria prevention, other effective and well-tolerated chemoprophylactic antimalarials should be available for Japanese travelers who do not tolerate mefloquine.
Antimalarials↗
Frequent detection of Epstein-Barr Virus and cytomegalovirus but not JC virus DNA in cerebrospinal fluid samples from human immunodeficiency virus-infected patients in northern Thailand.
Applying nested-PCRs, we frequently detected DNA of Epstein-Barr virus and cytomegalovirus but not JC virus in cerebrospinal fluid samples from 140 human immunodeficiency virus-infected patients with central nervous system symptoms in northern Thailand. Despite the low incidence of primary central nervous system lymphoma or cytomegalovirus encephalitis among Thai AIDS patients, Epstein-Barr virus and cytomegalovirus infections in the central nervous system are common.
Adult↗
Limited sequence evolution within persistently targeted CD8 epitopes in chronic human immunodeficiency virus type 1 infection.
Studies in acute human immunodeficiency virus type 1 (HIV-1) infection indicate viral evolution under CD8 T-cell immune selection pressure, but the effects of ongoing immune pressure on epitope evolution during chronic infection are not well described. In this study, we performed a detailed longitudinal analysis of viral sequence variation within persistently targeted cytotoxic T-lymphocyte (CTL) epitopes in two HIV-1-infected persons during 6 years of persistent viremia. Responses were quantitated using freshly isolated peripheral blood lymphocytes in direct lytic assays as well as by gamma interferon (IFN-gamma) Elispot assays on cryopreserved cells. Seven targeted epitopes were identified in each person. In the majority of cases, the dominant epitope sequence did not change over time, even in the presence of responses of sufficient magnitude that they were detectable using fresh peripheral blood mononuclear cells in direct lytic assays. Only 4 of the 14 autologous epitopes tested represented potential CTL escape variants; however, in most cases strong responses to these epitopes persisted for the 6 years of study. Although persistent IFN-gamma responses were detected to all epitopes, direct lytic assays demonstrated declining responses to some epitopes despite the persistence of the targeted sequence in vivo. These data indicate limited viral evolution within persistently targeted CD8 T-cell epitopes during the chronic phase of infection and suggest that these regions of the virus are either refractory to sequence change or that persistently activated CD8 T-cell responses in chronic infection exert little functional selection pressure.
Acquired Immunodeficiency Syndrome↗
Clinical characteristics of imported malaria in Japan: analysis at a referral hospital.
Imported malaria remains an important problem in Japan. We have reviewed the medical records of 170 cases of malaria in our hospital, which corresponds to 14.9% of the total cases in Japan. The predominant malarial species was Plasmodium falciparum (52.3%), and the most frequent area of acquisition was Africa (54.2%), followed by Asia (20.9%) and Oceania (19.6%). The most common reason for travel among Japanese patients was business. A significant proportion (22.2%) of vivax malaria cases experienced relapse despite standard primaquine therapy. Most primaquine failures were from Oceania. We also found that a substantial number of Japanese patients contracted malaria without chemoprophylaxis and consulted medical facilities with an unfavorably long delay from initial symptoms (median: 3.0 days). Direct education of travelers and travel companies, in addition to health care providers, is likely necessary to improve outcomes of imported malaria.
Adult↗
Acute disseminated encephalomyelitis following Plasmodium vivax malaria.
A 24-year-old Japanese man showed neurological disturbances 2 weeks after complete recovery from Plasmodium vivax infection. Magnetic resonance (MR) images of the brain showed multiple high-intensity spotty lesions in the left cerebral cortex and subcortex. Cerebrospinal fluid examination, including polymerase chain reaction analysis for viruses, revealed no sign of active infection. Repeated blood smears were negative for malaria. We diagnosed acute disseminated encephalomyelitis (ADEM) following Plasmodium vivax malaria from the clinical course and MR images. ADEM should be regarded as one of the neurological complications after malarial infection.
Adult↗
Molecular analysis of human herpesvirus 8 by using single nucleotide polymorphisms in open reading frame 26.
Human herpesvirus 8 (HHV-8) can be classified into distinct subtypes on the basis of sequence polymorphisms in several open reading frames (ORFs). We analyzed the subtypes of HHV-8 in 59 human immunodeficiency virus-infected Japanese patients by using polymorphisms in ORF26 and found that over two-thirds of the HHV-8 isolates fell into major subtype A. We also found that single nucleotide polymorphisms (SNPs) at nucleotide positions 1032 (C-to-A substitution) and 1055 (G-to-T substitution) in HHV-8 ORF26 were correlated with increased susceptibility to Kaposi's sarcoma, compared to the results obtained with HHV-8 with wild-type nucleotides at these positions (P = 0.0106). This observation suggests that molecular heterogeneity of the HHV-8 genome affects the biological properties of HHV-8, resulting in different clinical phenotypes of HHV-8 infection. Since sensitive PCR of ORF26 allowed us to analyze the SNPs by using peripheral blood from HHV-8-infected patients, the ORF26 SNPs will be a potent tool for investigating the pathogenesis of HHV-8 infection.
AIDS-Related Opportunistic Infections↗
The first isolation of Nocardia nova from an HIV-1 infected individual in Japan.
Nocardia species are opportunistic pathogens of immunocompromised patients. We report a case of Nocardia nova infection complicating Pneumocystis carinii pneumonia (PCP) in an HIV-1 infected individual. A 27-year-old man with hemophilia A was admitted on October 17, 2000, with fever and dyspnea. CD4 cell counts were 5/microl on admission. Prophylaxis against PCP was administered by inhalation of pentamidine isethionate because he was allergic to sulfamethoxazole-trimethoprim (SMZ-TMP). He was diagnosed with PCP from chest X-ray and bronchoalveolar lavage. The sputum obtained for culture on admission was positive for Gram-positive branching rods; the organism was later identified as Nocardia nova. He died from respiratory failure on November 7, 2000. Although PCP might be a principal factor in respiratory failure, this case shows the need to consider pulmonary nocardiosis as a cause of respiratory illness in patients with advanced HIV-1 infection.
Acquired Immunodeficiency Syndrome↗