Atsuko Nabeshima

Seroepidemiology of hepatitis C virus infection in hemodialysis patients and the general population in Fukuoka and Okinawa, Japan

In 1992, a seroepidemiologic study was carried out among hemodialysis patients and the general population in Fukuoka and Okinawa, Japan to determine the presence of hepatitis C virus (HCV) infection and HCV viremia. The markers used were antibody to HCV, determined by second-generation assay (anti-HCV), and HCV RNA, determined by the polymerase chain reaction. The prevalence of anti-HCV in Fukuoka was 3.3%, 73 per 2237 persons, significantly (P<0.001) higher than the 0.4%, 5 per 1295, in Okinawa. The prevalence of anti-HCV in hemodialysis patients in Fukuoka was 51.9% (161 of 310 patients), significantly (P<0.001) higher than the 9.1% (13 of 143 patients) in Okinawa. The ratio of HCV RNA-positive to anti-HCV-positive persons was significantly higher in hemodialysis patients (147/174, 84.5%) than in the general population (49/78, 62.8%) (P<0.001). Elimination of HCV among hemodialysis patients appears to be difficult, as such patients have lower immune responses than the general population. In Fukuoka, but not in Okinawa, blood used for transfusion was supplied by paid donors at commercial blood banks from 1953 to 1969. This may explain why HCV infection is endemic in Fukuoka and not in Okinawa. Differences between the prevalence of anti-HCV in the hemodialysis patients in Fukuoka and Okinawa reflect differences in the prevalence in the general population in these two areas of Japan.

Comparison of HCV RNA levels by branched DNA probe assay and by competitive polymerase chain reaction to predict effectiveness of interferon treatment for patients with chronic hepatitis C virus

To compare hepatitis C virus (HCV) RNA levelsdetermined by branched DNA probe assay and bycompetitive polymerase chain reaction (PCR) aspredictive markers of the response to interferon fortreatment of patients with chronic HCV infection, westudied data on 140 patients treated for six months withnatural interferon-alpha. Serum samples were tested forHCV RNA by PCR. HCV RNA was grouped into four genotypes by PCR with type-specific primers,and HCV RNA level was measured by branched DNA probeassay and by competitive PCR. HCV RNA was detected inall patients prior to initiation of the treatment. A complete response, sustained elimination ofHCV RNA, occurred in 51 patients (36.4%). With multiplelogistic regression analysis assessment, when usingcompetitive PCR, a low level of HCV RNA (P < 0.0001), younger age (P = 0.0054) and genotype 2a and 2b(P < 0.0158) were significant predictive markers fora complete response to interferon treatment. When usingbranched DNA probe assay, a low level of HCV RNA (P < 0.0001) and age (P = 0.0089) werepredictive markers, but genotype was not. The branchedDNA probe assay had a narrower linear range forquantitation of HCV RNA level than competitive PCR. In conclusion, HCV RNA level determined bybranched DNA probe assay proved to be useful forprediction of effects of interferon and it is costeffective as a marker of complete response to interferontreatment for patients with chronic HCVinfection.

Identifying interacting predictors of falling among hospitalized elderly in Japan : A signal detection approach

Falling is a complex phenomenon that involves interaction of multiple risk factors. The authors analyzed factors related to falls in a geriatric hospital to elucidate interaction of multiple risk factors for falls in elderly inpatients. Subjects were 364 patients (mean age, 81.7; women 76.7%) who were aged 60 years and over and had been hospitalized for more than 6 months between April 2000 and March 2001. A signal detection model was used to identify baseline variables that best divided the sample into subgroups using incidence of falling as an outcome variable. During a follow‐up period, 91 patients (25%) had at least one incident of fall. Out of 14 independent variables, a higher‐order interaction consisting of six significant variables was identified. Consequently, the subjects were categorized into seven subgroups whose fall rate varied 5.7–80.9%. We found that the combination of non‐bedridden state, dementia, and medication of tranquilizers or sleeping drugs was the highest fall rate (80.9%). Signal detection analysis is useful to identify the combination of multiple risk factors of falling, and applicable to develop prevention programs for each subgroups.

The relationship between the daily dosage of the carbapenem meropenem (MEPM) and MEPM-resistant Pseudomonas aeruginosa

Pseudomonas aeruginosa is a pathogen which is known to be responsible for nosocomial infection. The appropriate use of antibiotics has become important for preventing the spread of drug-resistant P. aeruginosa. In Hara-doi Hospital, two carbapenem antibiotics, imipenem (IPM) and meropenem (MEPM), are used for patients aged 65 years or older at a daily dosage of 1.0 g and 0.5 g, respectively. Of P. aeruginosa samples isolated in 2003, the sensitivity to IPM was 54% and to MEPM it was 58%. In 2004, the sensitivity to IPM was 55%, i.e., not significantly different from 2003. In 2004, the daily dosage of MEPM was increased to 1.0 g/day, and the sensitivity to MEPM increased to 71%. Based on the Pharmacokinetics/Pharmacodynamics (PK/PD) theory, even though the patients were elderly, a sufficient dosage of antibiotics given over a shorter period of time was effective against MEPM-resistant P. aeruginosa in a hospital ward, and there were no side effects.

Evaluation of a rapid enzyme immunoassay for detection of influenza A virus among adult and elderly patients

Directigen Flu A, an enzyme immunoassay membrane test for the detection of influenza A virus, was compared with serum hemagglutinine inhibition assay in adult and elderly patients. Throat specimens were collected by vigorous swabbing from febrile patients who were suspect for influenza by clinical symptoms and tested with Directigen Flu A. Serum samples were collected from the patients at onset of illness and two to eleven weeks later and tested for antibody titer to influenza A/H1N1, A/H3N2, and B. A total of 57 patients were involved in this study; 32 under 59 years of age and 25 over 60 years of age. Influenza was diagnosed in 42 patients by HI titer elevation (73.7%). Directigen Flu A was positive in 25 patients. Results of Directigen Flu A and HI test agreed in 40 patients. Sensitivity and specificity of Directigen Flu A were 59.5% (25/42) and 100% (15/15), respectively. There was no significant difference in sensitivity between the two age groups. These results indicate the potential usefulness of Directigen Flu A in the surveillance of influenza A infection in the geriatric population. Directigen Flu A gives results within 15 minutes without expensive equipment. Use of Directigen Flu permits the timely administration of antiviral therapy and infection control among hospitalized and institutionalized geriatric patients.