Search PubMed⌕ Search

Biomedical subjects

T Yoshiyama

Publications and source records attributed to T Yoshiyama.

At least 19 recordsLinked to original sources
PubMed2002

Current epidemiological trend of tuberculosis in Japan.

OBJECTIVE: To observe the recent epidemiological trend of tuberculosis and to determine the factors related to the deteriorating trend in incidence and mortality rates in Japan. DESIGN: Descriptive analyses of tuberculosis notification rates and mortality rates by age, sex, year and birth-cohort. RESULTS: The decline in the tuberculosis notification rate has started slowing down since around 1980. Among the cohorts born before 1950, the trend of notification rate by age has levelled off since around 1980. The reduction in the tuberculosis mortality rate has also recently begun to slow down, but later and to a lesser extent than that of the notification rate. Although deaths due to tuberculosis occur mostly among the elderly, the rate of decline in mortality among middle-aged males has slowed down recently. The trend in the mortality rate of birth-cohorts has recently shown an upward trend with age. CONCLUSION: A major cause of the current stagnation of the decline in notification rates is the increase in the elderly population with a high prevalence of tuberculosis infection in the past, who are more likely to develop the disease as they approach biological senescence. Other possible causes are a gradual shift of the tuberculosis problem to socio-economically deprived segments of the urban population, and behavioural changes causing delay in case-finding.

Adolescent↗
PubMed2001

Change of migration time and separation window accompanied by field-enhanced sample stacking in capillary zone electrophoresis.

When field-enhanced sample stacking was used in capillary zone electrophoresis (CZE) analysis of cations, the decrease of migration time and the reduction of separation window was observed with increase of sample plug length. A simple equation expressing the migration velocity in the stacking process was derived to explain the above phenomenon. From experiments and theoretical consideration, we confirmed that this effect was caused by the higher potential gradient and larger eletroosmotic flow (EOF) mobility at the sample plug than those at the supporting electrolyte. A mathematical model appropriate for the computer simulation of such a system was studied considering the experimental results, and it was concluded that electroosmotic velocity (v(eof)) should be introduced to the equation of continuity as a constant.

Cations↗
PubMed2001

Prevalence of drug-resistant tuberculosis in an HIV endemic area in northern Thailand.

SETTING: Chiang Rai Province in Northern Thailand, where human immunodeficiency virus (HIV) infection has been prevalent since the 1990s. OBJECTIVE: To observe the prevalence of drug-resistant tuberculosis (TB) and investigate the factors related to the level of drug resistance in an HIV endemic area. DESIGN: Population-based surveillance study covering the whole province. METHOD: Drug susceptibility testing was performed at the Thai Ministry of Public Health laboratory for all sputum smear-positive TB patients diagnosed in hospitals in Chiang Rai Province over a 25-month period in 1996-1998. Patient characteristics were obtained through interview by trained personnel. HIV testing was performed with informed consent. RESULTS: Among the 1077 incident patients without previous history of treatment, the proportion of patients with resistance to isoniazid was 13.2%, 10.8% to rifampicin, 15.6% to streptomycin, and 5.8% to ethambutol. Multidrug resistance (MDR), i.e., resistance to at least both isoniazid and rifampicin, was observed in 6.3%. Factors associated with primary MDR-TB were HIV positivity (OR 2.2, 95%CI 1.3-3.9), age <50 years (OR 2.0), and treatment in the provincial hospital (OR 2.3), compared to patients treated in the community and private hospitals. Stratified analysis shows a significantly high prevalence of primary MDR-TB among HIV-positive patients treated in the provincial hospital against HIV-negative patients or HIV-positive patients in other hospitals. CONCLUSION: The prevalence of primary MDR-TB in this area was high. It is necessary to strengthen TB control activities in order to reduce the burden of MDR-TB.

AIDS-Related Opportunistic Infections↗
PubMed2001

[Tuberculosis].

Explore the source record for details and available documents.

Age Factors↗
PubMed2000

New method for standardization of electropherograms obtained in capillary zone electrophoresis.

A new method for standardization of electropherograms obtained by capillary zone electrophoresis was proposed, where the migration time axis was replaced by the effective mobility axis. The mobility increase due to temperature increase by Joule heating and the relaxation effect of the potential gradient were eliminated successfully by introducing a temperature coefficient for mobility expression and a delay time, respectively. The precision of the mobility evaluated by the proposed conversion methods was evaluated for a model sample. By using the conversion method, almost the same electropherograms could be obtained even from the electropherograms originally obtained by using different hardware conditions.

Electrophoresis, Capillary↗
PubMed2000

Standardization of capillary zone electropherograms obtained by using field enhanced sample stacking.

Migration times in a capillary zone electropherogram obtained by using the field enhanced sample stacking technique are strongly affected by the injected sample volume. That is, the migration times significantly decrease with the increase of the sample volume. To avoid inaccurate qualitative analysis due to the above phenomena, the time axis of the electropherograms was converted into an effective mobility axis using our conversion method taking account of the temperature increase in the separation tube and relaxation of the potential gradient of the separation field. After the conversion, accurate qualitative analysis was possible in spite of drastic change of the migration time, suggesting our conversion method could be successfully used for the standardization of electropherograms obtained even by using the stacking effect. The cause of the decrease of the migration time in the stacking process was briefly discussed.

Electrophoresis, Capillary↗
PubMed2000

[Epidemiology and control activities of tuberculosis in Japan].

Tuberculosis has declined in Japan for 50 years, however it is more prevalent than other developed countries and speed of decline is much slower recently in Japan than in European countries in 1950-80s when the incidence rate was almost the same as that in Japan now. Most of old cases were reactivation and most of young cases were those soon after new infection. Early case detection and treatment and cutting the chain of transmission is necessary for the reduction of young cases. The defaulter rate among smear positive new cases is 3.6% and is higher among non-skilled workers. DOT has not been widely done on outpatient clinic basis but should be considered for those who cannot stay in hospitals.

Age Factors↗
PubMed2000

[Cost effectiveness analysis of isoniazid preventive therapy to the contacts of tuberculosis patients under Japanese settings].

The target for isoniazid preventive therapy against tuberculosis in Japan has been contact persons of tuberculosis patients with the age of less than 30. This paper discusses about the cost effectiveness analysis of preventive therapy with the mathematical model. The effectiveness was measured with averted tuberculosis cases, averted death, averted loss of DALY (disability adjusted life years), averted loss of healthy years of life. With all indicators, isoniazid preventive therapy was effective if preventive chemotherapy is given to persons younger than 70 years old and with the higher probability of new infection than 20%, and if it is given following the present criteria of tuberculin testing for preventive therapy in Japan. The total medical cost is cheaper among persons with the preventive therapy than those without the preventive therapy, if the probability of new infection among the contact persons is more than 29% at the age of 40. The isoniazid preventive therapy for health care workers, whose prevalence of infection is higher than the average population, was also effective in both cases with and without baseline tuberculin testing. However, the positive predictive value of criteria of preventive therapy highly depends on the probability of new infection.

Adult↗
PubMed2000

[Limits of nucleic acid amplification tests for diagnosis of smear negative pulmonary tuberculosis].

STUDY OBJECTIVES: To assess the usefulness of commercial kits of nucleic acid amplification test (NAAT) for diagnosis of smear negative (SN) pulmonary tuberculosis. DESIGN AND PATIENTS: Retrospective study of patients who were diagnosed as, or suspected of pulmonary tuberculosis during 3 years from January 1996 to December 1998 in Fukujuji Hospital which has 100 beds for tuberculosis patients. MEASUREMENTS AND RESULTS: 145 smear-negative culture-positive pulmonary tuberculosis patients are entered to our analysis. The DNA-based amplification test kit (Amplicor Mycobacterium Tuberculosis Test (AMPL), Roche Diagnostic Systems, Basel, Switzerland) detected 39.2% (20/51, 95% confidence interval (CI): 25.8-52.6%) of smear-negative culture-positive (SNCP) pulmonary tuberculosis cases. The RNA-based amplification test kit (Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test (AMTDT), Gen-Probe Inc., San Diego, Calif., USA) detected 40.5% (15/37, 95% CI: 24.7-56.3%) of SNCP pulmonary tuberculosis cases. For both NAATs (AMPL and AMTDT), between two groups with and without the NAAT at diagnosis of SNCP pulmonary tuberculosis, there was statistical difference in culture-positive rate (proportion of positivity in sputum culture tests at diagnosis), but no statistical difference in maximum number of colony of Mycobacterium tuberculosis (MTB). When stratified for the culture-positive rate, adjusted sensitivity for SNCP patients was 44.2% (AMPL) and 40.4% (AMTDT) respectively. On the other hand, among 245 patients with sputum AMPL positive results during the 3 years, 8 were smear-negative culture-negative (SNCN), only one out of these 8 cases was judged as true active tuberculosis without treatment. Among 89 patients with sputum AMTDT positive results, 7 were SNCN, and 3 out of them were judged as true active tuberculosis without treatment. CONCLUSION: Usefulness of commercial NAAT kits (AMPL and AMTDT) to diagnosis SN pulmonary tuberculosis is limited in the point of sensitivity.

DNA, Bacterial↗
PubMed1999

[Comparison of double-segment technique with single-space technique for cesarean section using combined spinal epidural anesthesia].

In patients scheduled for cesarean section (c-section) using combined spinal epidural anesthesia (CSEA), we compared the cephalad spreading speed during double-segment technique (DST) with that of single-space technique (SST) of CSEA. In the patients of SST group (n = 169), a 17-G Tuohy needle was introduced at the L 3-4, and then a long spinal needle was inserted through the Tuohy needle. In the patients of DST group (n = 16), a Tuohy needle was introduced at the T 11-12, and a spinal needle was inserted at the L 3-4. After 0.3% hyperbaric dibucaine 1.0 ml was injected through the spinal needle, 1.5% mepivacaine 10 ml was injected through the epidural catheter in both the groups. The analgesic level was measured at 5-min intervals, and blood pressure and complaints of patients were also recorded. The cephalad spread of analgesia was significantly higher in DST group than in SST group at 5 and 10 min after the administration of local anesthetics. Two patients in SST group, epidural catheterization was not possible. There were no difference in the incidences of hypotension, nausea and dyspnea between the groups. We conclude from these results that DST for CSEA is preferable to SST for c-section.

Adult↗
PubMed1999

[Severe hypoxia due to persistent left supra vena cava draining to the left atrium after weaning from cardiopulmonary bypass in a patient with endocardial cushion defect].

We report a case of severe hypoxia after weaning from cardiopulmonary bypass in a ten-month-old patient with endocardial cushion defect. The severe hypoxia was improved abruptly when the persistent left supra vena cava (PLSVC) was ligated. The hypoxia, therefore, was considered to be caused by venous blood which was directly drained into the left atrium through the PLSVC. In cases with large right-to-left shunt which is difficult to explain only by intracardiac shunt, attention must be paid to existence of PLSVC directly draining into the left atrium.

Anesthesia, General↗
PubMed1999

[Six-months chemotherapy (2HRZS or E/4HRE) of new cases of pulmonary tuberculosis--six year experiences on its effectiveness, toxicity, and acceptability].

The incidence of tuberculosis in Japan, 33.7 per 100,000 in 1997, is very high compared with USA or Western European countries. The decrease in the incidence has slowed down from the early 1980s, and the average annual rate of decrease has been 3.8% in the last 5 years. About 9 percent of tuberculosis patients defaulted from the nine-month regimen (6HRS or E/3HR) in urban areas. Regimens shorter than nine-month are needed to achieve high effectiveness of tuberculous chemotherapy. Out of 1128 new pulmonary tuberculosis patients, six-hundred twenty started treatment with six-month (2HRZS or E/4HRE) in Fukujuji Hospital, JATA, in Tokyo from January 1991 to December 1996. Out of 620, four-hundred twenty eight were both smear and culture positive, 136 were smear negative and culture positive and 56 were bacilli negative. Out of 564 bacilli positive cases, 530 were susceptible to INH and RFP. Out of 530 drug susceptible cases three hundred ninety-three patients completed the regimen. Ninety-three percent of these patients had converted to negative at two months of chemotherapy and all of them at five months. Out of 450, two-hundred ninety five completed 6-month regimen, one-hundred fifty-five were changed their regimen or prolonged duration of chemotherapy. Out of 295, nine patients (3.1%) relapsed after the completion of 6-month chemotherapy. Mean follow-up period was 17.2 months and the median was 15.5 months. The relapse rate was 2.2 per 100 person-years. Six of the relapsed cases were complicated with Diabetes Mellitus. Relapse rate was higher in patients with Diabetes Mellitus than in patients without (6/54, 7.9 per 100 person-years vs 3/237, 0.8 per 100 person-years) (p < 0.001). Drug-induced hepatotoxicity was defined as elevated serum transaminase level with clinical symptoms of hepatitis or elevated serum transaminase level more than 5 times of upper limit of normal range with or without symptoms. Drug-induced hepatotoxicity developed in 43 (8.0%) of 535 with initial normal liver function test results, this rate was similar to that in patients treated with nine-month regimen (34/420, 8.1%). But the frequency of hepatotoxicity of more than 400 IU/ml of serum transaminase level was higher in patients treated with PZA-containing regimen than with nine-month regimen (16/536, 3.0% vs 4/420, 1.0%), but this deference was not statistically significant. Hepatotoxicity developed in 13/85 (15.3%) of patients treated with PZA-containing regimen with abnormal liver function tests at the beginning of chemotherapy, and this frequency was similar to 7/65 (10.8%) in patients with nine-month regimen. The relapse rate in patients with Diabetes Mellitus was statistically higher than in without Diabetes Mellitus (7.9 vs 0.8 per 100 person-years). We concluded that the six-month regimen was highly effective, but the frequency of severe hepatotoxicity was relatively higher than in nine-month regimen and the duration of chemotherapy was not enough for patients complicated with Diabetes Mellitus. Further study is needed for sufficient chemotherapy in patients with Diabetes Mellitus.

Adult↗
PubMed1999

[Current epidemiological trend of tuberculosis among foreigners in Japan].

In Japan, the proportion of foreign patients among the total tuberculosis patients is still very small, but their problems in tuberculosis case finding and treatment require intensive control activities as in other low prevalence countries with higher proportion of foreign-born cases. The latest national survey for the foreign tuberculosis patients conducted in 1996 shows the epidemiological status between 1990 and 1993. The number of foreign tuberculosis patients in 1993 was 484, consisting of 1.0% of the total new patients in Japan. The new case rate among foreigners was estimated to be 53 per 100,000 against 38 for whole Japan in 1993. Compared with the figure in the 1993 survey, the number of foreign patients declined from 585 in 1992 to 484 in 1993. However, the number of bacillary positive tuberculosis patients in 1992 was 230 and almost the same as in 1992. The decline or stagnation of total number of tuberculosis patients can be due either to the decrease in the foreign population inflow into Japan (real decline), or partially to the reduction of overdiagnosis in X ray examination and the possible loss of some cases in the 1996 survey method. A manual sorting method from the registration cards was used at each public health center, since there is no item of country of origin in the routine tuberculosis surveillance system, and some cards might have already been displaced by the time of the survey for patients who were excluded from the registry, either cured, died or defaulted. The average treatment completion rate (1991-93) among foreign patients was 51%, which was much lower than the national figure of 81% for the same years. Moreover the rate showed deteriorating trend by year. For more accurate information, the foreigner's data must be taken in the national tuberculosis surveillance system and control activities for foreigners need to be strengthened.

Adolescent↗
PubMed1999

[Cross-contamination of Mycobacterium tuberculosis culture in clinical laboratories].

For many years, it has been thought that positive culture of M. tuberculosis is a definitive diagnostic evidence of tuberculosis and cross-contamination of M. tuberculosis culture in clinical laboratories is rare. However recently introduced RFLP analysis has enabled us to identify a strain of M. tuberculosis, and many cases of the cross-contamination in clinical laboratories confirmed by RFLP analysis have been reported. In this report, we present the first case of the cross-contamination confirmed by RFLP in Japan. In our case, 5 patients without any personal link to each other were suspected based on clinical findings to have cross-contaminated results of M. tuberculosis culture. All their specimens were processed on the same day, and were smear negative and culture positive with only a small number of colonies (less than 8 colonies). The sputum from the suspected source of contamination processed on the same day was strongly positive for AFB smear and heavily culture positive. The RFLP patterns of these 6 patients were identical, so it was concluded that the positive cultures of the sputum from the 5 patients who were not expected to be culture positive on clinical findings were caused by the cross-contamination in our hospital laboratory. We review all the charts of patients with M. tuberculosis culture positive results in the same year of this case, but we didn't find no other cases suspected of the cross-contamination. Then we reviewed the literature of M. tuberculosis culture cross-contamination. The patterns of the cross-contamination are divided into two. One is associated with malfunction of a sampling needle in the BACTEC 460 system and the other associated with the initial processing of the specimens, mostly involving reagents such as NaOH solution. Cross-contaminated specimens are usually smear negative with only a few colonies (less than 5), and processed just after the source specimen of the contamination in most reported cases, but not in all. In almost half of them the cross-contamination results had significant influence on the clinical management. The frequency of the cross-contamination is estimated around 1% of the patients with M. tuberculosis culture positive results. For early detection of the cross-contamination, not only clinicians but also laboratory staffs have important role and close cooperation between them is mandatory. To prevent the contamination, it is advisable to process smear positive and probable culture positive specimens separately from others, and not to use a large same container of reagents for processing of different specimens.

Adult↗
PubMed1998

[Multidrug-resistant tuberculosis. 3. Epidemiology of drug-resistant tuberculosis in Japan].

In Japan, the frequency of drug-resistant tuberculosis has been investigated every 5 years since 1950s and increase of initial and acquired drug resistance has not been observed. However, the mathematical model analyse of time trend of prevalence of drug-resistant tuberculosis and frequency of initial drug resistance in Korea shows that there is little difference of infectivity and/or proportion of clinical breakdown between susceptible bacilli and resistant ones. The prognosis of isoniazid (INH) and rifampicin (RFP) resistant tuberculosis cases in Fukujuji Hospital was investigated. 367 cases including 50 initial drug resistant cases were analyzed with life table analysis. 50% of all cases and 70% of initial drug resistant cases became negative, 13% of all cases and 4% of initial drug resistant cases remained as positive, 37% of all cases and 27% of new cases died. Among cases who did not convert negative within one year, 41% of all cases and 34% of initial drug resistant cases died. The prognosis of INH and RFP resistant tuberculosis cases were still not satisfactory.

Adolescent↗
PubMed1995

Endothelium-dependent and -independent vasodilation of isolated rat aorta induced by caffeine.

Caffeine (10(-4)-10(-3) M) induced concentration-dependent relaxations of phenylephrine-precontracted rat aortic rings with endothelium. Endothelial denudation significantly, but only partially, attenuated caffeine-induced relaxation. Pretreatment with NG-nitro-L-arginine, oxyhemoglobin, and methylene blue attenuated the relaxations to an extent similar to endothelial denudation. Guanosine 3',5'-cyclic monophosphate (cGMP) and adenosine 3',5'-cyclic monophosphate (cAMP) contents of aortic strips with endothelium increased significantly after exposure to caffeine (10(-3) M). Endothelial denudation attenuated caffeine-induced cGMP increase. Pretreatment with ryanodine (2 x 10(-5) M), which has been shown to combine with receptors on endoplasmic reticulum (ER) of endothelium, attenuated caffeine-induced relaxation and cGMP content increase of rings with endothelium. Pretreatment with caffeine potentiated sodium nitroprusside-induced relaxations and cGMP increase of rings without endothelium. These results demonstrated that caffeine-induced relaxation comprises two components. In the endothelium-dependent mechanism, caffeine promotes nitric oxide synthesis in endothelium by release of Ca2+ from ER through a ryanodine-sensitive Ca2+ channel, and the suppression of cGMP degradation also contributes to the relaxation. In the endothelium-independent mechanism, caffeine acts as a 3',5'-cyclic-nucleotide phosphodiesterase inhibitor.

Animals↗