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Biomedical subjects

N Chiba

Publications and source records attributed to N Chiba.

At least 19 recordsLinked to original sources
PubMed2006

The prevalence of Barrett's oesophagus in a cohort of 1040 Canadian primary care patients with uninvestigated dyspepsia undergoing prompt endoscopy.

BACKGROUND: The prevalence of Barrett's oesophagus in patients undergoing gastroscopy may be influenced by possible referral bias. AIM: To present the prevalence of Barrett's oesophagus from the the Canadian Adult Dyspepsia Empirical Therapy Prompt Endoscopy study and to explore potential risk factors for its presence. METHODS: Patients had not been on treatment for dyspepsia for 2-4 weeks prior to endoscopy, which was performed within 10 working days of presentation. RESULTS: Barrett's oesophagus was endoscopically suspected in 53 of 1040 cases (5%) and histologically confirmed by the presence of intestinal metaplasia in 25 (2.4%). The prevalence of biopsy-proven Barrett's oesophagus was 4% in patients with dominant reflux-like symptoms. Sixty-four percent with confirmed Barrett's oesophagus had dominant reflux-like symptoms compared with 37% without Barrett's oesophagus. Barrett's oesophagus was more common in patients >50 years of age; 68% of cases were males. The mean duration of symptoms was 10 years, yet 16% had symptoms of <1-year duration. Endoscopic reflux oesophagitis was present in 68% of confirmed Barrett's oesophagus patients. CONCLUSIONS: Barrett's oesophagus is confirmed on biopsy in about half of endoscopically suspected Barrett's oesophagus patients. Barrett's oesophagus is more common in males, in those with dominant reflux-like symptoms, and in patients with a longer symptom history.

Aged↗
PubMed2006

Validation of a 7-point Global Overall Symptom scale to measure the severity of dyspepsia symptoms in clinical trials.

BACKGROUND: Currently there is no consensus on the optimal method to measure the severity of dyspepsia symptoms in clinical trials. AIM: To validate the 7-point Global Overall Symptom scale. METHODS: The Global Overall Symptom scale uses a 7-point Likert scale ranging from 1 = no problem to 7 = a very severe problem. Validation was performed in two randomized-controlled trials (n = 1121 and 512). Construct validity: Global Overall Symptom was compared with the Quality of Life in Reflux And Dyspepsia, Gastrointestinal Symptom Rating Scale, Reflux Disease Questionnaire and 10 specific symptoms using Spearman correlation coefficients. Test-retest reliability: The Intraclass Correlation Coefficient was calculated for patients with stable dyspepsia defined by no change in Overall Treatment Effect score over two visits. Responsiveness: effect size and standardized response mean were also calculated. RESULTS: Construct validity: Change in Global Overall Symptom score correlated significantly with Quality of Life for Reflux And Dyspepsia, Gastrointestinal Symptom Rating Scale, Reflux Disease Questionnaire and specific symptoms (all P < 0.0002). Reliability: The Intraclass Correlation Coefficient was 0.62 (n = 205) and 0.42 (n = 270). Responsiveness: There was a positive correlation between change in Global Overall Symptom and change in symptom severity. The effect size and standardized response mean were 1.1 and 2.1, respectively. CONCLUSION: The Global Overall Symptom scale is a simple, valid outcome measure for dyspepsia treatment trials.

Adolescent↗
PubMed2006

Validation of a symptom diary for patients with gastro-oesophageal reflux disease.

BACKGROUND: Symptom diaries are potentially attractive but, because of concerns about patient compliance, they have had limited use in clinical trials. We assessed the validity and responsiveness of a symptom diary for patients with gastro-oesophageal reflux disease. METHODS: We included 215 patients with gastro-oesophageal reflux disease after starting treatment for 4 weeks with 40 mg esomeprazole once daily. Patients recorded whether they experienced night-time heartburn (yes/no), the severity of daytime heartburn on a scale from 1 (no heartburn) to 4 (severe heartburn) and their antacid use. Patients also completed a number of disease-specific and preference-based Health-related Quality of Life questionnaires at baseline and follow-up. RESULTS: Consistent with a priori predictions, daytime heartburn showed moderate to strong correlations with the Quality of Life in Reflux and Dyspepsia questionnaire (0.36-0.67) and four scales of symptom severity (0.36-0.70) for baseline, follow-up and change scores, but low correlations with the Standard Gamble. Responsiveness of the daytime heartburn item was excellent with a mean change from baseline to follow-up of -1.3 (95% CI -1.4 to -1.1) and a standardized response mean of 1.33 while responsiveness of the daily antacid use item was moderate (mean change scores -1.8 tablets taken, 95% CI -2.3 to -1.3 and standardized response mean of 0.64). CONCLUSIONS: The excellent psychometric properties of this simple gastro-oesophageal reflux disease diary make it an attractive measure for future trials.

Antacids↗
PubMed2006

Changes in coagulative and fibrinolytic activities in patients with intracranial hemorrhage.

OBJECTIVE: To investigate whether any changes occur in the coagulative/fibrinolytic cascade in patients with subarachnoid hemorrhage (SAH) or hypertensive intracerebral hemorrhage (HICH). DESIGN AND METHODS: Subjects included 143 patients with intracranial hemorrhage (SAH, n = 50; HICH, n = 82; ROSC-SAH [return of spontaneous circulation after cardiopulmonary arrest due to SAH], n = 11). Coagulative and fibrinolytic factors were measured in blood samples taken on admission. RESULTS: The prothrombin fragment 1+2 level was significantly higher (p < 0.005) in SAH patients than in HICH patients. The fibrinolytic factors (plasmin alpha 2-plasmin inhibitor complex, D-dimer, or fibrinogen degradation products) in SAH and ROSC-SAH were both significantly higher than those in HICH, but the significance of difference was stronger in the case of ROSC-SAH (p < 0.05). DISCUSSION: Both coagulative and fibrinolytic activities were altered after the onset of SAH. These results demonstrate that the coagulative/fibrinolytic cascade might be activated via different mechanisms in different types of stroke. It remains unclear, however, whether a significant alteration of the fibrinolytic cascade in patients with ROSC-SAH might be a nonspecific phenomenon attributable to the reperfusion after collapse.

Blood Coagulation↗
PubMed2006

Effect of non-steroidal anti-inflammatory ophthalmic solution on intraocular pressure reduction by latanoprost in patients with primary open angle glaucoma or ocular hypertension.

AIM: To investigate the effects of a non-steroidal anti-inflammatory drug (NSAID) ophthalmic solution on latanoprost induced intraocular pressure (IOP) reduction in glaucoma patients. METHODS: Examination was conducted on 16 eyes of 16 glaucoma patients who had been given only latanoprost for at least 6 weeks. The NSAID ophthalmic solution, sodium 2-amino-3-(4-bromobenzoyl) phenylacetate sesquihydrate, was additionally given for 12 weeks into one eye (NSAID group), while sodium hyaluronic acid ophthalmic solution was administered into the other eye (control group) in a double masked fashion. The IOP measurement was performed before the start of additional administration of ophthalmic solutions, 2, 4, 6, 8, 10, and 12 weeks after the start of additional administration, and 2, 4, and 6 weeks after discontinuing additional administration. RESULTS: No significant difference was observed in the IOPs before additional administration of ophthalmic solution between the NSAID group and the control group. Following the additional administration of ophthalmic solution, IOP in the NSAID group was consistently higher than that in the control group, and a maximum difference in IOP between the two groups was 1.08 (SD 1.75) mm Hg (p = 0.03). This trend was observed even after additional administration was discontinued. CONCLUSION: NSAID ophthalmic solution may partly affect IOP reduction by latanoprost.

Adult↗
PubMed2006

Pb(II) biosorption on reed biosorbent derived from wetland: effect of pretreatment on functional groups.

Reed biomass harvested from wetland constructed for water purification was modified into a biosorbent for Pb(ll) removal from aqueous solution. The enhancement of Pb(ll) adsorption by reed biosorbent depended not only on the types of reagent used for pretreatment, but also on the pH during the pretreatment process. The mechanisms, as elucidated using relational data obtained from Boehm titration, Fisher esterification and FTIR, involved the conversion of carboxylic groups into carboxylate groups, and proved the role of the carboxylate group, which occupied more than 80% in binding Pb(ll). The Langmuir sorption isotherm of Pb(ll) by R-NaOH-12 showed QO, and b values of 0.082 mmol/g and 312.5 g/mmol, suggesting enough adsorption performance to reduce the concentration of Pb(ll) to meet the range of WHO guidelines. The salinity of aqueous solution containing NaH2PO4 and NaN03 promoted the adsorption of Pb(ll), while NaCl and Na2SO4 suppressed the adsorption capacity of Pb(ll). The adsorption mechanism of reed biosorbent provides valuable insight on the pretreatment effects and the advantages of utilizing this plant as biosorbent for Pb(ll) and other heavy metals.

Adsorption↗
PubMed2005

Heartburn-dominant, uninvestigated dyspepsia: a comparison of 'PPI-start' and 'H2-RA-start' management strategies in primary care--the CADET-HR Study.

BACKGROUND: There are few data on empiric, stepped therapy for heartburn relief or subsequent relapse in primary care. AIMS: To compare heartburn relief produced by a proton pump inhibitor-start or an H(2)-receptor antagonist-start with step-up therapy, as needed, followed by a treatment-free period to assess relapse. METHODS: Heartburn-dominant uninvestigated dyspepsia patients from 46 primary care centres were randomized to one of two active treatment strategies: omeprazole 20 mg daily (proton pump inhibitor-start) or ranitidine 150 mg bid (H2-receptor antagonist-start) for the first 4-8 weeks, stepping up to omeprazole 40 or 20 mg daily, respectively, for 4-8 weeks for persistent symptoms. Daily diaries documented heartburn relief (score < or = 3/7 on < or = of 7 prior days) and relapse (score > or = 4 on > or = 2 of 7 prior days). RESULTS: For 'proton pump inhibitor-start' (n = 196) vs. 'H2-receptor antagonist-start' (n = 194), respectively, heartburn relief occurred in 55.1% vs. 27.3% (P < 0.001) at 4 weeks and in 88.3% vs. 87.1% at 16 weeks. After therapy, 308 patients were heartburn-free (159 vs. 149); median times to relapse were 8 vs. 9 days and cumulative relapse rates were 78.6% vs. 75.8%, respectively. CONCLUSIONS: An empiric 'proton pump inhibitor-start' strategy relieves heartburn more effectively than an 'H2-receptor antagonist-start' strategy up to 12 weeks but has no effect on subsequent relapse, which is rapid in most patients.

Adolescent↗
PubMed2004

Do physicians correctly assess patient symptom severity in gastro-oesophageal reflux disease?

BACKGROUND: The accuracy of physicians' assessment of the severity of gastro-oesophageal reflux disease is unclear. AIM: To correlate physician and patient assessment of gastro-oesophageal reflux disease severity and its response to treatment. METHODS: Adult uninvestigated gastro-oesophageal reflux disease patients (n = 217) completed symptom and health-related quality of life questionnaires at baseline and after treatment with esomeprazole 40 mg p.o. daily. Pearson coefficients quantified correlations between physician assessments and patient responses. RESULTS: At baseline, the strongest correlations were heartburn severity (0.31), overall symptom severity (0.44) and a domain of the quality of life in reflux and dyspepsia questionnaire (0.31) (P < 0.001). Correlations of change with treatment were greater than baseline correlations: heartburn (0.39), overall symptoms (0.50) and global rate of change -- stomach problems (0.72, all P < 0.001). The mean difference between the physicians' assessment of change and the patients' global rating of change was 0.20 (95% confidence intervals: 0.10-0.29) with physicians overestimating benefit. CONCLUSIONS: Correlations were often significant, although weak to moderate and better with symptom severity than with health-related quality of life instruments as well as with change after therapy than at baseline. Increasing attention to health-related quality of life may help physicians better understand patients' experience. In clinical trials, treatment success should be assessed by the patient as well as the physician.

Adolescent↗
PubMed2004

Economic evaluation of Helicobacter pylori eradication in the CADET-Hp randomized controlled trial of H. pylori-positive primary care patients with uninvestigated dyspepsia.

BACKGROUND: Adult Helicobacter pylori-positive patients by 13C-urea breath test with uninvestigated dyspepsia symptoms were randomized to 1-week eradication treatment with omeprazole, metronidazole and clarithromycin (OMC) vs. omeprazole and placebo antimicrobials (OPP) in the Canadian Adult Dyspepsia Empiric Treatment-H. pylori-positive (CADET-Hp) study. AIM: To perform an economic evaluation of this 1-year study. METHODS: Following blind eradication treatment, family practitioners managed patients according to their usual practices. Health resource utilization information was collected prospectively. From the mean costs of the health resources consumed and the treatment outcomes, the incremental cost-effectiveness ratios and incremental net benefits of eradication treatment vs. OPP were determined. RESULTS: Eradication therapy significantly improved dyspepsia symptoms (treatment success: OMC, 50%; OPP, 36%; P = 0.02). The incremental cost-effectiveness ratio of OMC vs. OPP was - 387 Canadian dollars (CAD$) per treatment success (90% CI, - CAD$1707, CAD$607), indicating a lower cost with treatment success. The incremental net benefit analysis showed that H. pylori eradication was cost-effective if the willingness-to-pay value exceeded a nominal figure of CAD$100 from a health service perspective or CAD$607 from the societal perspective. CONCLUSION: In uninvestigated patients presenting with dyspepsia at the primary care level, eradication of H. pylori in those who are H. pylori positive leads to a cost-effective improvement in dyspepsia symptoms compared with a strategy of not eradicating H. pylori in these patients.

Adolescent↗
PubMed2004

Specific alcoholic beverage and blood pressure in a middle-aged Japanese population: the High-risk and Population Strategy for Occupational Health Promotion (HIPOP-OHP) Study.

The purpose of this study was to clarify the effects of popular Japanese alcoholic beverages on blood pressure. We performed a cross-sectional study on 4335 Japanese male workers using baseline data from an intervention study. We defined six groups according to the type of alcoholic beverage that provided two-thirds of the subject's total alcohol consumption: beer, sake (rice wine), shochu (traditional Japanese spirits), whiskey, wine and others. The partial regression coefficients of daily alcohol intake (1 drink=11.5 g of ethanol) to systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 0.87(P<0.001, standard error (s.e.)=0.09) and 0.77(P<0.001, s.e.=0.06), respectively. A comparison among the types of alcoholic beverages mainly consumed revealed significant differences in SBP and DBP. Both SBP and DBP were highest in the shochu group. However, an analysis of covariance adjusting for total alcohol consumption resulted in the disappearance of these differences. Although after adjustment for total alcohol consumption, the shochu group exhibited a significant positive association with 'high-normal blood pressure or greater' (odds ratio 1.43, 95% confidence interval 1.06-1.95) compared with the beer group, this significant relation disappeared after adjusting for the body mass index (BMI), urinary sodium and potassium excretion. The pressor effect, per se, of popular Japanese alcoholic beverages on blood pressure may not be different among the types of alcoholic beverages after adjusting for other lifestyle factors.

Adult↗
PubMed2004

The high-risk and population strategy for occupational health promotion (HIPOP-OHP) study: study design and cardiovascular risk factors at the baseline survey.

In order to establish the methodology of a population strategy for improving cardiovascular risk factors, we have planned the High-risk and Population Strategy for Occupational Health Promotion Study (HIPOP-OHP study). This study is a nonrandomized control trial in approximately 6500 participants in six intervention and six control companies. Our population strategy is based on three factors, nutrition, physical activity, and smoking. For each factor, a researcher's working team was organized and has been supporting the intervention. A standardized method to obtain comparable data has also been established. In the baseline survey, urinary sodium excretion in male subjects was higher, and urinary potassium excretion was lower in both genders in the intervention group compared to the control group. The prevalence of hypertension for both genders was also higher in the intervention group. Male subjects in the intervention group had higher serum total cholesterol than controls, while high-density lipoprotein cholesterol was lower in both genders in the intervention group compared to the control group. These differences were reflected by our finding that the predicted relative risk of coronary heart disease for male subjects was significantly higher in the intervention group (relative risk, RR: 1.17; 95% confidence interval, 95% CI.: 1.09, 1.25) and significantly lower in the control group (RR: 0.93; 95% CI.: 0.89, 0.98) compared to a model Japanese population. Similar results were observed in the female subjects. Taken together, these findings indicate that it is possible to compare trends of predicted relative risk for coronary heart disease between two groups.

Adult↗
PubMed2003

The prevalence of clinically significant endoscopic findings in primary care patients with uninvestigated dyspepsia: the Canadian Adult Dyspepsia Empiric Treatment - Prompt Endoscopy (CADET-PE) study.

BACKGROUND: Uninvestigated dyspepsia is common in family practice. The prevalence of clinically significant upper gastrointestinal findings (CSFs) in adult uninvestigated dyspepsia patients, and their predictability based on history, is unknown. METHODS: Prompt endoscopy was performed within 10 days of referral, in 1040 adult patients presenting with uninvestigated dyspepsia at 49 Canadian family practitioner centres. Subsequent management strategies during a 6-month follow-up period were determined by the individual family practitioners. RESULTS: CSFs were identified in 58% (603/1040) of patients. Erosive oesophagitis was most common (43%; N = 451); peptic ulcer was uncommon (5.3%; N = 55). Alarm symptoms were uncommon (2.8%; N = 29). Most patients had at least three dyspepsia symptoms, more than 80% had at least six, and approximately half had eight or more. Based on the dominant symptom, 463 (45%) patients had ulcer-like, 393 (38%) had reflux-like and 184 (18%) had dysmotility-like dyspepsia. The patients' dominant symptom was not predictive of endoscopic findings. Oesophagitis was more common in those with dominant reflux-like symptoms and was the most common finding in all subgroups. The prevalence of gastroduodenal findings was similar in all symptom subgroups. Helicobacter pylori (H. pylori) infection (30%; 301/1013) was associated with gastroduodenal findings. CONCLUSIONS: Dyspepsia subclassifications, based on dominant symptom, are of limited value in predicting the presence and nature of CSFs. Oesophagitis was by far the most common diagnosis (43% of patients). CSFs were common in uninvestigated dyspepsia patients and their nature suggests patients could be initially treated effectively, without endoscopy, using empirical acid suppressive therapy.

Adolescent↗
PubMed2003

Comparison of iridial pigmentation between latanoprost and isopropyl unoprostone: a long term prospective comparative study.

AIM: To compare incidence of iridial pigmentation prospectively induced by long term treatment with latanoprost and isopropyl unoprostone (hereafter, unoprostone) in Japanese patients with glaucoma. METHODS: Patients with glaucoma treated with prostaglandin (PG) related ophthalmic solutions were sequentially enrolled. Patients treated for more than 30 months with PG related ophthalmic solutions were subjected to analysis. The entry criteria were no history of intraocular surgery, laser iridotomy, and/or laser trabeculoplasty within 12 months before and after the enrolment; and no history of uveitis; no changes in antiglaucoma drugs within 6 months before and after the enrolment. Photographs of the irides were taken under the same conditions and three glaucoma specialists evaluated the iridial pigmentation with masking of patient information. The correlation of iridial pigmentation with the background factors and the reduction of intraocular pressure (IOP) before and after the treatment were investigated. RESULTS: 48 eyes in 48 patients satisfied the enrolment criteria (25 eyes in the latanoprost group, 23 eyes in the unoprostone group). At the end of the follow up period, iridial pigmentation was present in 15 patients (60.0%) in the latanoprost group and seven patients (30.4%) in the unoprostone group. The correlation between development of iridial pigmentation and age, sex, concurrent use of other ophthalmic solutions, and IOP reduction was not significant. CONCLUSIONS: The incidence of iridial pigmentation induced by latanoprost or unoprostone is high in the case of long term treatment. Iridial pigmentation did not affect PG related ophthalmic solution induced IOP reduction.

Adult↗
PubMed2001

3-(Arylacetylamino)-N-methylbenzamides: a novel class of selective anti-Helicobacter pylori agents.

After chemical modification preceded by the random screening of our chemical library, a novel class of selective anti-Helicobacter pylori agents was generated. Consequently, the 3-(arylacetylamino)-N-methylbenzamides, which were quite easy to prepare, showed potent inhibitory activity against Helicobacter pylori but exhibited no inhibitory activity against other sorts of bacteria and fungi, e.g., Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Bacteroides fragilis, and Candida albicans. These compounds showed potent anti-H. pylori activity under acidic conditions, whereas amoxicillin and clarithromycin decreased activity. The 3-(3-arylpropionylamino)-N-methylbenzamides, 3-(aryloxyacetylamino)-N-methylbenzamides, and (3-methylcarbamoylphenyl)carbamic acid 1-arylmethyl esters also exhibited potent anti-H. pylori activity. Finally, we selected 7n (BAS-118) as a candidate compound for further evaluation.

Anti-Bacterial Agents↗
PubMed2001

Redistribution of BRCA1 among four different protein complexes following replication blockage.

The BRCA1 protein is known to participate in multiple cellular processes. In these experiments, we resolved four distinct BRCA1-containing complexes. We found BRCA1 associated with the RNA polymerase II holoenzyme (holo-pol), a large mass complex called the fraction 5 complex, the Rad50-Mre11-Nbs1 complex, and a complex that has not been described previously. We observed this new complex after treating cells with hydroxyurea, suggesting that the hydroxyurea-induced complex (HUIC) is involved with the response to DNA replication blockage. After hydroxyurea treatment of cells, BRCA1 content decreased in the holo-pol and the fraction 5 complex, and BRCA1 was redistributed to the HUIC. The HUIC was shown not to contain a number of holo-pol components or the Rad50-Mre11-Nbs1 complex but was associated with the BRCA1-associated RING domain protein BARD1. These data suggest that BRCA1 participates in multiple cellular processes by multiple protein complexes and that the BRCA1 content of these complexes is dynamically altered after DNA replication blockage.

Adenoviridae↗
PubMed2001

Survival and sinus rhythm maintenance after modified Cox/maze procedure and mitral valve operation in patients with chronic atrial fibrillation.

OBJECTIVE: Sinus rhythm gained after the Cox/maze procedure concomitant with mitral valve operation has demonstrated long-term attrition during the follow-up, no information exists on whether the type of mitral valve operation--(repair vs. replacement)--affects this sinus rhythm maintenance rate. We retrospectively studied patients undergoing concomitant mitral valve operation and Cox/maze procedure to answer this question. METHODS: Between April 1993 and August 1995, 87 consecutive patients--35 men and 52 women (mean age: 59.3 years)--with chronic atrial fibrillation and mitral valve disease underwent the modified Cox/maze procedure and concomitant mitral valve operation, with 56 having mitral valve repair (repair group) and 31 mitral valve replacement (replacement group). Patients were followed up and changes in rhythm studied retrospectively. RESULTS: Follow-up for a mean 51.3 +/- 11.6 months was completed in 82 of 83 long-term survivors (99%). Repair group surgery survival was 98.1 +/- 1.9% at 1 year and 94.2 +/- 3.2% at 5 based on the Kaplan-Meier method. Replacement group surgery survival was 85.7 +/- 5.9% at 1 year and 82.9 +/- 6.4% at 5. Probability in sinus rhythm maintenance for the repair group at 1 year was 88.6 +/- 5.4% and at 5 years was 67.6 +/- 9.1%. Probability in sinus rhythm maintenance for the replacement group at 1 year was 95.7 +/- 4.3% and at 5 years was 65.0 +/- 11.1%. CONCLUSIONS: Medium-term results after the Cox/maze III procedure concomitant with mitral valve operation are good. The attrition of sinus rhythm maintenance appears similar by the completion of 5-year follow-up.

Atrial Fibrillation↗
PubMed2001

Ca(2+) function in photosynthetic oxygen evolution studied by alkali metal cations substitution.

Effects of adding monovalent alkali metal cations to Ca(2+)-depleted photosystem (PS)II membranes on the biochemical and spectroscopic properties of the oxygen-evolving complex were studied. The Ca(2+)-dependent oxygen evolution was competitively inhibited by K(+), Rb(+), and Cs(+), the ionic radii of which are larger than the radius of Ca(2+) but not inhibited significantly by Li(+) and Na(+), the ionic radii of which are smaller than that of Ca(2+). Ca(2+)-depleted membranes without metal cation supplementation showed normal S(2) multiline electron paramagnetic resonance (EPR) signal and an S(2)Q(A)(-) thermoluminescence (TL) band with a normal peak temperature after illumination under conditions for single turnover of PSII. Membranes supplemented with Li(+) or Na(+) showed properties similar to those of the Ca(2+)-depleted membranes, except for a small difference in the TL peak temperatures. The peak temperature of the TL band of membranes supplemented with K(+), Rb(+), or Cs(+) was elevated to approximately 38 degrees C which coincided with that of Y(D)(+)Q(A)(-) TL band, and no S(2) EPR signals were detected. The K(+)-induced high-temperature TL band and the S(2)Q(A)(-) TL band were interconvertible by the addition of K(+) or Ca(2+) in the dark. Both the Ca(2+)-depleted and the K(+)-substituted membranes showed the narrow EPR signal corresponding to the S(2)Y(Z)(+) state at g = 2 by illuminating the membranes under multiple turnover conditions. These results indicate that the ionic radii of the cations occupying Ca(2+)-binding site crucially affect the properties of the manganese cluster.

Calcium↗