Comparing factors related to perceived control and preventive behaviors from COVID-19 between Japanese and American nursing students: A cross-sectional study

AIM

Higher levels of perceived control are important to maintain health. The difference in factors related to perceived control and preventive behaviors during the COVID-19 pandemic between Japanese and American nursing students remains unknown. This study aimed to compare factors related to perceived control and infection preventive behaviors between the two countries.

METHODS

This cross-sectional study included nursing students attending four universities in Japan and one in the United States. Using Google Forms, the participants answered a survey comprising sociodemographic data, the Perceived Control and Self-Efficacy Scale, the Perceived Health Competence Scale, and a preventive behavior questionnaire. The data were collected from November 2020 to May 2021. Linear and logistic regressions were used to analyze the factors related to perceived control and preventive behaviors, respectively.

RESULTS

Data from 878 students were analyzed. University/campus emerged as a strong predictor for perceived control and preventive behaviors in both countries, with a positive correlation between perceived control and preventive behaviors. Older age, less frequent alcohol consumption, higher perceived health competence, less frequent work in Japan; and chronic conditions in the United States were associated with frequent preventive behaviors. Younger age was correlated with higher perceived control in Japan, while religion and increased workload were potential factors for American students.

CONCLUSION

Individual factors were pivotal in Japan, whereas interpersonal factors were more likely related to perceived control in the United States. Additionally, in both countries, policy or organizational factors significantly influenced students' preventive behaviors.

Cross-sectional study of factors related to COVID-19 vaccination uptake among university healthcare students

Introduction

Healthcare students are more likely to become infected than other university students as they may encounter patients with COVID-19 during clinical training. Vaccination uptake is essential to prevent infection. This study explored factors related to COVID-19 vaccination uptake among healthcare students.

Methods

This cross-sectional study conducted online surveys of undergraduate and graduate nursing and healthcare graduate students from four medical universities in the Tokyo Metropolitan Area of Japan. Data were collected from June to August 2022, when the fourth vaccination program was initiated.

Results

Data from 1,169 students were analyzed (response rate = 37.3%). The mean age was 25.1 ± 7.6 years, and most were female (82.3%). Academic majors included nursing (68.0%), medicine (16.3%), dentistry (9.3%), and others (6.4%). Thirty students (2.6%) were not vaccinated, one student (0.1%) had received one vaccination, 997 (85.3%) had received three, and 27 (2.3%) had received four. The major reason for not being vaccinated was insufficient confirmation of its safety (n = 25). Students who had received at least one vaccination (n = 1,139), 965 (84.7%) reported experiencing adverse side effects, the most frequent being pain at the injection site (76.2%), followed by fever (68.3%). In the logistic regression, a greater number of vaccinations (3-4 times) was associated with older age (odds ratio, OR = 1.53), working (OR = 1.67), and more frequent infection-preventive behaviors (OR = 1.05). Significantly fewer students were vaccinated at University B than at University A (OR = 0.46). Additionally, those majoring in subjects other than nursing (OR = 0.28), and students from non-Asian countries (OR = 0.30) were less likely to be vaccinated.

Discussion

It is necessary to pay attention to and encourage the vaccination of students who engage in low levels of preventive behavior, students who are young, international, or unemployed, and those in non-healthcare professional majors.

Factors related to mental health effect among nursing students in Japan and the United States during the coronavirus pandemic: A cross-sectional study

In the context of mental health, university students have been considered a vulnerable population. However, limited studies have underscored the association between preventive health behaviour levels and mental health effects among nursing students. The current cross-sectional study provides a comparative analysis of the impact of mental health factors on nursing students in Japan and the United States (US) in the context of the coronavirus disease 2019 (COVID-19) pandemic. The study consisted of 878 participants, comprising both undergraduate and graduate nursing students from four universities in Japan, and one from the US. Hierarchical logistic regression was used to analyse the participant data in this study. In contrast to the American students, the Japanese students demonstrated significantly lower levels of perceived control and significantly higher levels of preventive health behaviours. Furthermore, Japanese students exhibited significantly higher levels of stress and/or symptoms of depression induced by the social distancing orders compared to the American students (z = -4.218, P < 0.001). However, no difference was observed after adjusting for perceived control, individual factors, socio-economic factors, and preventive behaviours. During the pandemic, risk factors that can worsen mental health among the nursing students included younger age [odds ratio (95%CI) = 0.62 (0.48-0.81)], women [OR = 2.17 (1.02-4.61)], higher preventive health behaviour [OR = 1.05 (1.02-1.08)], lower perceived control [OR = 0.97 (0.94-0.99)], and lower perceived health competence [OR = 0.93 (0.90-0.96)]. Thus, this study recommends establishing training programmes that enhance perceived control and perceived health competence while encouraging preventive behaviour to support the mental health of nursing students, particularly young female students.

Association between lowering heart rate during IMPELLA support and favorable short-term outcome in patients with cardiogenic shock

Background

Impella has been increasingly used in patients with cardiogenic shock (CGS). Target values for clinical indices for appropriate management of Impella have not yet been established.

Purpose

We aimed to elucidate the association between heat rate (HR) during Impella treatment in patients with CGS and clinical outcomes.

Methods and results

We retrospectively evaluated 62 patients (68±14 years; male 77%) with CGS receiving temporary circulatory support with the Impella between February 1, 2019, and February 31, 2021. The primary end point was 30-day mortality. Clinical characteristics, laboratory and hemodynamic markers at implantation of Impella (baseline), 12, 24 hr after implantation, and removal of Impella were assessed. There were 28 patients with concomitant use of extracorporeal membrane oxygenation (ECMO). Treatment periods using Impella were 8±6 days. After excluding 11 patients who died during Impella support, the relationship between clinical indicators at each time points and 30-day mortality was evaluated. There were 22 patients (43%) with 30-day mortality. Factors associated with 30-day mortality were: female, ECMO, higher 24-hr lactate level, lower 24-hr cardiac power output, and higher HR at removal. Lower HR of ≤81 bpm at removal was found to most accurately predict lower 30-day mortality (Figure 1). Higher increases in dose of beta-blockers during Impella support and lower absolute doses of norepinephrine at removal were correlated with decreases in HR during Impella support.

Conclusions

In patients with CGS treated with Impella, lower HR at removal was associated with lower incidence of 30-day mortality. Lowering HR during Impella treatment was recognized as a simple indicator for favorable clinical outcomes in patients with CGS. It was suggested that chronotropic interventions during Impella treatment may be novel therapeutic options in patients with CGS.

Funding Acknowledgement

Type of funding sources: None. Figure 1

Factors related to perceived control and health-related quality of life of patients after acute coronary syndrome during admission and after discharge

Aim

To explore the relationship between demographic factors, acute coronary syndrome‐related factors, perceived control and health‐related quality of life during admission, 3 months and 6 months after discharge, in patients with acute coronary syndrome.

Methods

Participants were recruited for this longitudinal study after admission for acute coronary syndrome in three university hospitals in the Tokyo metropolitan area, Japan. Self‐administered questionnaires included demographic data, perceived control, health‐related quality of life, acute coronary syndrome symptoms, fatigue, depression and anxiety.

Results

Participants (N = 137) had an average age of 62.8 (SD 11.6) years and 80.3% were male. As a result of Path analysis, higher perceived control (β = 0.258, p = .001), lower anxiety (β = −0.226, p = .009) and lower fatigue (β = −0.231, p = .010), were significantly related to better health‐related quality of life (General health). Only annual income was significantly related to perceived control (β = 0.187, p = .029). Eighty‐two (59.9%) participants at 3 months and 54 (39.4%) participants at 6 months completed the questionnaires. Perceived control (F = 7.074, p = .001) and General health (χ² = 10.22, p = .006) significantly increased over the 6 months. Perceived control during admission was significantly related with health‐related quality of life at 3 months. Perceived control at 3 months was significantly related with health‐related quality of life at 6 months.

Conclusion

Perceived control was an important factor for health‐related quality of life of the Japanese patients with acute coronary syndrome. It is necessary to investigate whether nursing interventions to enhance perceived control lead to improvement of health‐related quality of life.

Perceived Control, Preventative Health Behaviors, and the Mental Health of Nursing Students During the COVID-19 Pandemic: A Cross-Sectional Study

Introduction: Perceived control is an individual's subjective beliefs about the amount of control he or she has over the environment or outcome. Objective: To examine the relationship between perceived control, preventive health behaviors, and mental health effects of undergraduate nursing students during the COVID-19 pandemic. Methods: This cross-sectional correlational study used online self-administered questionnaires. Participants were nursing students attending 3 universities in Tokyo, Japan. Relationships among variables were quantitatively analyzed using linear regressions and a structural equation modeling after adjusting for demographic factors. Results: A total of 557 students participated in the survey. The analysis indicated that higher levels of perceived control were significantly related to higher levels of preventive health behaviors. Although higher preventive health behaviors were related to negative mental health effects, higher levels of perceived health competence translated to improved mental health effects. Perceived control was not directly related to mental health effects but positively related to perceived health competence. Long work hours per week and short hours of sleep per day were associated with lower preventive health behaviors. There were significant differences in the levels of perceived control and preventive health behaviors among students at the 3 universities. Discussion: To improve health behaviors and health competence and subsequently alleviate the mental health effects caused by strictly adhering to recommended health behaviors, students may be supported by the strategies that increase their perceived control. In addition to institutional support, students also require adequate sleep and financial stability to help prevent infections while protecting their mental health.

Prognostic implications of late gadolinium enhancement for re-worsening left ventricular ejection fraction in patients with dilated cardiomyopathy: a longitudinal study of left ventricular function

Background

Re-worsening left ventricular ejection fraction (LVEF) after initial recovery occurs in some patients with dilated cardiomyopathy (DCM). However, prevalence and predictors of re-worsening LVEF in longitudinal follow-up are unclear. Late gadolinium enhancement of cardiovascular magnetic resonance (LGE-CMR) can evaluate the damage of myocardial tissue.

Purpose

This study sought to evaluate the clinical parameters including LGE-CMR to predict re-worsening LVEF in patients with recent-onset DCM.

Methods

We included patients with recent-onset DCM who had an LVEF &lt;45% and underwent LGE-CMR at diagnosis. We performed yearly echocardiographc follow-up [median 6 [4–8.3] years]. Initial LVEF recovery defined as patients increased in &gt;5% LVEF from baseline and had an LVEF≥45% after medical therapy. Patients were divided into three groups: (1) Improved: defined as those with sustained LVEF ≥45% after initial LVEF recovery; (2) Re-worse: those with decreased &gt;5% and had an LVEF &lt;45% after initial LVEF recovery. and (3) Not-improved: those with no initial LVEF recovery during follow-up. To evaluate the prognostic factors for Re-worsening LVEF after initial LVEF recovery, multivariate logistic regression analysis performed between the Improved group and the Re-worse group. Cardiac events defined as hospitalization due to heart failure and sudden death.

Results

Of 138 patents, 82 patients (59%) were the Improved group, 42 patients (30%) were the Re-worse group, and 14 (10%) were the Not-improved group. Loess curves of long-term LVEF trajectories showed that LVEF in the Re-worse group increased first 2 years and declined slowly thereafter (Fig. 1A). Re-worsening LVEF occurred 4.5±2.2 years after initial LVEF recovery. Multivariate logistic regression analysis demonstrated that LGE area at baseline (Odds ratio: 1.09, 95% confidence interval (CI) 1.02–1.18, p=0.014) and Log brain natriuretic peptide (BNP) at initial LVEF recovery (Odds ratio: 1.53, 95% confidence interval (CI) 1.01–2.31, p=0.042) were independent predictors for Re-worsening LVEF. Kaplan Meier analysis demonstrated that the risk of cardiac events in the Re-worse group was significantly higher (hazard ratio: 3.93, 95% CI 1.49–10.36, p=0.006) than in the Improved group and lower risk than in the Not-improved group (hazard ratio: 0.28, 95% CI 0.12–0.62, p=0.002) (Fig. 1B).

Conclusion

Re-worsening LVEF occurred in 30% of patients in patients with recent-onset DCM. LGE area and BNP at initial LVEF recovery were independently associated with re-worsening LVEF after initial LVEF recovery.

Figure 1

Funding Acknowledgement

Type of funding source: None

P338Combined assessment using clinical and imaging parameters to predict response to pharmacotherapy in patients with dilated cardiomyopathy

Background

Normalization of left ventricular (LV) contraction is a strong surrogate marker of favorable prognosis in patients with dilated cardiomyopathy (DCM). Although several studies have reported the individual predictive significance of clinical and imaging parameters for LV recovery in patients with DCM, there have been no reports on the scoring systems that combine these multifactorial parameters.

Methods and results

In 406 idiopathic patients with DCM, there were 185 (46%) with LV recovery at 1-year follow-up after pharmacotherapy, which was defined as improvements in LV ejection fraction of ≥+10% together with absolute values of ≥50%. Multivariate analysis demonstrated that eight baseline clinical factors and the absence of late gadolinium enhancement (negative LGE) on magnetic resonance imaging were independently associated with LV recovery. The highest odds ratio for the prediction of LV recovery was negative LGE (odds ratio: 5.62, 95% confidence interval: 2.97–10.6; p<0.0001). Response score for the prediction of LV recovery that included these nine parameters had a predictive accuracy of 0.76 for LV recovery (Figure).

Conclusion

Combined assessment using clinical and imaging parameters has a high prognostic value for predicting response to pharmacotherapy in patients with DCM.

Double-blind, placebo-controlled pilot trial of anthocyanin-rich purple sweet potato beverage on serum hepatic biomarker levels in healthy Caucasians with borderline hepatitis

The objective is to evaluate the efficacy of anthocyanin-rich purple-fleshed sweet potato (PSP) beverage on the serum levels of gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in healthy Caucasians with borderline hepatitis. Forty healthy Caucasians (41-69 years) consumed three bottles of the PSP beverage (177 mg anthocyanins per 125-ml bottle) or placebo (1.3 mg) per day for 8 weeks. Thirty-nine subjects completed the study and two subjects were excluded from statistical analysis. GGT levels in the PSP group on days 15 and 43 were lower (P=0.077 and 0.038, respectively), AST levels in the PSP group on days 29 and 43 were lower (P=0.010 and 0.045, respectively) and ALT level in the PSP group on day 43 was lower (P=0.037) than in the placebo group. The PSP beverage did not induce clinically relevant changes in other blood and clinical chemistry parameters.

Anti-Human Immunodeficiency Virus (HIV) Activity of the Novel Antiviral Antibiotic Quartromicins which Enhance Inhibitory Effect of 3′-azido-2′,3′-dideoxythymidine (AZT) in vitro

Novel antiviral antibiotic quartromicins A1 and D1, isolated from Amycolatopsis orientalis, significantly inhibited human immunodeficiency virus (HIV)-induced cytopathic effect and virus specific antigen expression at concentrations of 25–100 μg ml−1 In MT-4 cells infected with HTLV-IIIB. The reverse transcriptase activity of disrupted HTLV-IIIB particles, recombinant HIV-1 enzyme, and purified avian myeloblastosis virus (AMV) enzyme were also significantly inhibited by quartromicins A1 and D1. The combined antiviral effect of quartromicin A1 and AZT on the replication of HIV in MT-4 cells was also examined. Quartromicin A1 synergistically enhanced the inhibitory effect of AZT as revealed by HIV-specific antigen expression.

Successful delivery following intracytoplasmic sperm injection with calcium ionophore A23187 oocyte activation in a partially globozoospermic patient

PURPOSE

To describe a successful pregnancy outcome following intracytoplasmic sperm injection (ICSI) with assisted oocyte activation (AOA) in a case of partial globozoospermia.

METHODS

AOA was accomplished with calcium ionophore A23187. Sperm morphology was observed via light, fluorescent and electron microscopy following a Diff-Quik stain and fluorescein isothiocyanate-labeled peanut agglutinin (FITC-PNA) staining. An activation ability test was employed using a mouse oocyte exposed to strontium chloride.

RESULTS

Via light microscopy, it was found that a large number of sperm possessed deficient acrosomes and a sharply rounded head; however, we observed both normal and the aforementioned abnormal sperm via FITC-PNA staining of a semen specimen. Mouse oocyte activation was 87.5 % via natural activation without AOA. With AOA after ICSI, 100 % oocyte activation was observed. Five oocytes were retrieved, and AOA with A23187 after ICSI resulted in a high fertilization rate (4 of 5, 80 %). Two embryos developed and the patient subsequently delivered a healthy female infant without any congenital abnormalities.

CONCLUSIONS

We report a successful pregnancy outcome using an early stage embryo, which developed following ICSI using sperm from a partially globozoospermic patient who possessed temporary potential oocyte activation.

Expression of ADAMTS4 in Ewing's sarcoma

Ewing's sarcoma (EWS) is a malignant bone tumor that frequently occurs in teenagers. Genetic mutations which cause EWS have been investigated, and the most frequent one proved to be a fusion gene between EWS gene of chromosome 22 and the FLI1 gene of chromosome 11. However, a limited numbers of useful biological markers for diagnosis of EWS are available. In this study, we identified ADAMTS4 (a disintegrin and metalloproteinase with thrombospondin motifs) as a possible tumor marker for EWS using the retrovirus-mediated signal sequence trap method. ADAMTS4 is a secreted protein of 837 amino acids with a predicted molecular mass of 98-100 kDa. It is a member of metalloprotease family, is expressed mainly in cartilage and brain, and regulates the degradation of aggrecans. ADAMTS4 has been suggested to be involved in arthritic diseases and gliomas. Herein, we show that ADAMTS4 mRNA was expressed in all primary EWS samples and all EWS-derived cell lines examined, while its expression was detected only in small subpopulations of other solid tumors. Furthermore, ADAMTS4 expression was found to be regulated by EWS-FLI1 fusion gene-dependent manner. We also demonstrated that ADAMTS4 protein was highly expressed in tumor samples of the patients with EWS by using immunohistochemistry. These results suggest that ADAMTS4 is a novel tumor marker for EWS.

AID-induced T-lymphoma or B-leukemia/lymphoma in a mouse BMT model

Activation-induced cytidine deaminase (AID) diversifies immunoglobulin through somatic hypermutation (SHM) and class-switch recombination (CSR). AID-transgenic mice develop T-lymphoma, indicating that constitutive expression of AID leads to tumorigenesis. Here, we transplanted mouse bone marrow cells transduced with AID. Twenty-four of the 32 recipient mice developed T-lymphoma 2-4 months after the transplantation. Surprisingly, unlike AID-transgenic mice, seven recipients developed B-leukemia/lymphoma with longer latencies. None of the mice suffered from myeloid leukemia. When we used nude mice as recipients, they developed only B-leukemia/lymphoma, presumably due to lack of thymus. Analysis of AID mutants suggested that an intact form with SHM activity is required for maximum ability of AID to induce lymphoma. Except for a K-ras active mutant in one case, specific mutations could not be identified in T-lymphoma; however, Notch1 was constitutively activated in most cases. Importantly, truncations of Ebf1 or Pax5 were observed in B-leukemia/lymphoma. In conclusion, this is the first report on the potential of AID overexpression to promote B-cell lymphomagenesis in a mouse model. Aberrant expression of AID in bone marrow cells induced leukemia/lymphoma in a cell-lineage-dependent manner, mainly through its function as a mutator.

Assessment of abnormal left atrial relaxation by transesophageal pulsed Doppler echocardiography of pulmonary venous flow velocity

BACKGROUND

Several studies on left ventricular relaxation have been undertaken in the past; however, left atrial (LA) relaxation has not been fully evaluated.

HYPOTHESIS

The purpose of this study was to assess abnormalities in LA relaxation by evaluating pulmonary venous flow velocity and interatrial septal motion using transesophageal echocardiography.

METHODS

The subjects were 56 untreated patients in sinus rhythm, including 25 with previous myocardial infarction, 9 with hypertrophic cardiomyopathy, 11 with dilated cardiomyopathy, as well as 11 with chest pain syndrome as controls. Peak first systolic velocity (PVS1), peak atrial systolic velocity (PVA), and their time-velocity integrals (PVS1-I and PVA-I, respectively) were calculated from the pulmonary venous flow velocity.

RESULTS

The PVS1 and PVS1-I correlated negatively with the maximum LA dimension and mean pulmonary capillary wedge pressure, and correlated positively with the amplitude of the interatrial septal motion during LA relaxation and percent fractional LA relaxation. The PVA and PVA-I did not correlate with the mean pulmonary capillary wedge pressure. There was a weak positive correlation between PVA and PVS1, and a close positive correlation between the ratio of PVA to PVS1 and mean pulmonary capillary wedge pressure. Multiple regression analysis indicated that the PVS1 was most closely related to percent fractional LA relaxation, followed by mean pulmonary capillary wedge pressure.

CONCLUSION

The PVS1 determined from the pulmonary venous flow velocity is closely related to parameters of LA relaxation which may be determined by transesophageal M-mode echocardiography, and the ratio of PVA to PVS1 is useful for noninvasive evaluation of LA pressure.

Evaluation of left atrial filling using systolic pulmonary venous flow velocity measurements in patients with atrial fibrillation

BACKGROUND

The pattern of pulmonary venous flow velocity is useful for understanding the hemodynamic relationship between the left atrium and left ventricle in patients with a variety of diseases, and the systolic flow wave, in particular, is considered a clinically important parameter that reflects left atrial filling.

HYPOTHESIS

The study was undertaken to determine whether systolic pulmonary venous flow velocity patterns can be used to evaluate left atrial filling in patients with atrial fibrillation.

METHODS

We performed transesophageal pulsed Doppler echocardiography and cardiac catheterization in 34 patients with chronic atrial fibrillation (10 with hypertrophic cardiomyopathy, 5 with dilated cardiomyopathy, 7 with previous myocardial infarction, and 12 with isolated atrial fibrillation) and 15 normal controls in sinus rhythm.

RESULTS

Mean pulmonary capillary wedge pressure, V-wave height in the pulmonary capillary wedge pressure curve, and left ventricular end-diastolic pressure were significantly higher in the hypertrophic cardiomyopathy and dilated failing heart (previous myocardial infarction and dilated cardiomyopathy) groups than in the isolated atrial fibrillation and normal groups. The peak velocity and time-velocity integral of the systolic pulmonary venous flow velocity, and percent left atrial emptying fraction were significantly lower in the dilated failing heart group than in the isolated atrial fibrillation, hypertrophic cardiomyopathy, and normal groups. The peak velocity and time-velocity integral of the systolic pulmonary venous flow velocity, percent left atrial emptying fraction, and V-wave height were comparatively constant when the preceding R-R intervals were relatively stable in the isolated atrial fibrillation group and in 4 of the 10 patients with hypertrophic cardiomyopathy. However, changes in these variables correlated with the preceding R-R interval in all patients with dilated failing hearts and in 6 of the 10 patients with hypertrophic cardiomyopathy.

CONCLUSION

Transesophageal pulsed Doppler echocardiographic measurements of systolic pulmonary venous flow velocity are valid indicators of left atrial filling in patients with atrial fibrillation.

Echocardiographic characteristics and causal mechanism of physiologic mitral regurgitation in young normal subjects

BACKGROUND

It has become evident that mitral regurgitation (MR) is not uncommon in healthy subjects, and Doppler color flow mapping is a technique that imparts important information relevant to its detection.

HYPOTHESIS

Using transthoracic echocardiography, this study evaluated the mechanism of physiologic MR in young normal subjects using transthoracic echocardiography.

METHODS

The study population consisted of 48 young normal subjects (mean 21 +/- 5 years) with MR (physiologic MR group), 40 age-matched young normal subjects (mean 20 +/- 5 years) without MR (control group), 45 patients (mean 41 +/- 15 years) with mitral valve prolapse with MR (MVP group), and 27 patients (mean 59 +/- 13 years) with ruptured chordae tendineae (rupture group).

RESULTS

Men were predominant in the rupture group, whereas there were no significant gender differences in the other three groups. Left ventricular end-diastolic dimension and left atrial systolic dimension were slightly smaller in the physiologic MR group than in the control group, but were significantly smaller than those in the MVP and rupture groups. The ratio of the maximum anteroposterior diameter to the maximum transverse diameter on chest radiography and the ratio of the short- to long-axis diameter of the left ventricular cavity at end diastole, determined from two-dimensional short-axis echocardiogram, were significantly lower in the physiologic MR group than in the other three groups. Mitral regurgitation occurred more frequently at the posteromedial commissural site in the physiologic MR and MVP groups, whereas there was no preference for location in the rupture group. Early systolic MR was often observed in the physiologic MR group, whereas pansystolic MR was common in the MVP and rupture groups.

CONCLUSION

As a causal mechanism for physiologic MR detected in young normal subjects, "flattening" of the thorax during growth may cause morphologic abnormalities of the left atrial and ventricular cavities, resulting in spatial imbalance of the mitral complex and resulting in malcoaptation of the valve.

Transesophageal pulsed Doppler echocardiographic evaluation of left atrial systolic performance in hypertrophic cardiomyopathy: combined analysis of transmitral and pulmonary venous flow velocities

BACKGROUND

Hypertrophic cardiomyopathy (HC) is characterized by impaired left ventricular (LV) diastolic function due to an increase in LV wall thickness. The severity of this disease varies depending on the localization and extent of the hypertrophied myocardium and the presence and extent of myocardial disarray or fibrosis.

HYPOTHESIS

The purpose of this study was to examine the background of hemodynamic abnormalities between the left atrium and the left ventricle during atrial systole in patients with HC using pulsed Doppler echocardiography.

METHODS

Hemodynamic abnormalities between the left atrium and left ventricle during atrial systole were evaluated in patients with HC using transmitral flow (TMF) and pulmonary venous flow (PVF) velocities obtained by transesophageal pulsed Doppler echocardiography. The study population included 50 patients with HC, including 39 with asymmetric septal hypertrophy and 11 with apical hypertrophy, and showing fractional shortening of the left ventricle > or = 30%. They were classified into three groups: (1) Group A (n = 11): the ratio of the late to early TMF velocity < 1, and peak atrial systolic PVF velocity (PVA) < 25 mm/s; (2) Group B (n = 13): their ratio < 1, and PVA > or = 25 mm/s; and (3) Group C (n = 26): their ratio > or = 1. The mean age of patients in Group A was lower than that in Groups B and C.

RESULTS

Left atrial dimension in Group B was significantly greater than that in the other HC groups and the control group. Furthermore, left atrial volume changes during atrial systole in Group B were significantly smaller than those in the other HC groups and the control group. Peak atrial systolic PVF velocity in Group B was significantly higher than that in the control group and in Group C. The duration of the atrial systolic waves of the TMF and PVF in Group B was significantly shorter and longer, respectively, than that in Group A. Left ventricular end-diastolic pressure (LVEDP) decreased in descending order with Group B > Group C > Group A. In all patients there was a significant positive correlation between the LVEDP and peak atrial systolic PVF velocity or the difference in duration between the atrial systolic waves of PVF and TMF. Plots of these values shifted toward the left and inferiorly in Group A, and toward the right and superiorly in Group B.

CONCLUSION

Peak velocity and duration of TMF and PVF during atrial systole by transesophageal pulsed Doppler echocardiography are useful indices of hemodynamic abnormalities between the left atrium and the left ventricle during atrial systole, particularly a forceful atrial contraction mismatched to the left atrial afterload and severity of LV diastolic dysfunction, in HC.

Evaluation of miniY-STR multiplex PCR systems for extended 16 Y-STR loci

We developed three short amplicon Y-chromosomal short tandem repeat (miniY-STR) polymerase chain reaction multiplex systems for 16 Y-STR loci (DYS441, DYS446, DYS462, DYS481, DYS485, DYS495, DYS505, DYS510, DYS511, DYS549, DYS 575, DYS578, DYS593, DYS618, DYS638, and DYS643), using newly designed primer sets. In an assay of 238 Japanese males using the three miniY-STR systems, amplification product lengths ranged from 91 to 151 bp for all 16 Y-STR loci. We identified 212 different haplotypes among the 238 individuals, finding haplotype diversity and discrimination capacity of 0.9974 and 0.8908, respectively. An assay of degraded DNA samples using the three miniY-STR multiplex systems, including artificially degraded samples and degraded forensic casework samples, proved remarkably effective. In conclusion, analyses of miniY-STR multiplex systems will play an important role in forensic applications involving degraded DNA samples for which genotyping using only commercial kits is ill-suited.

Identification of TSC-22 as a potential tumor suppressor that is upregulated by Flt3-D835V but not Flt3-ITD

Transforming growth factor-beta (TGF-beta)-stimulated clone-22 (TSC-22) was originally isolated as a TGF-beta-inducible gene. In this study, we identified TSC-22 as a potential leukemia suppressor. Two types of FMS-like tyrosine kinase-3 (Flt3) mutations are frequently found in acute myeloid leukemia: Flt3-ITD harboring an internal tandem duplication in the juxtamembrane domain associated with poor prognosis and Flt3-TKD harboring a point mutation in the kinase domain. Comparison of gene expression profiles between Flt3-ITD- and Flt3-TKD-transduced Ba/F3 cells revealed that constitutive activation of Flt3 by Flt3-TKD, but not Flt3-ITD, upregulated the expression of TSC-22. Importantly, treatment with an Flt3 inhibitor PKC412 or an Flt3 small interfering RNA decreased the expression level of TSC-22 in Flt3-TKD-transduced cells. Forced expression of TSC-22 suppressed the growth and accelerated the differentiation of several leukemia cell lines into monocytes, in particular, in combination with differentiation-inducing reagents. On the other hand, a dominant-negative form of TSC-22 accelerated the growth of Flt3-TKD-transduced 32Dcl.3 cells. Collectively, these results suggest that TSC-22 is a possible target of leukemia therapy.

Associated Reaction and Spasticity Among Patients with Stroke

OBJECTIVES

The objectives were to investigate the relationship between associated reaction (AR) and clinical spasticity in the paretic arm.

DESIGN

The participants were ten patients with hemiparetic stroke, mean age of 65.2 yrs, and duration of stroke of 13.3 mos. The AR of the hemiparetic arm was analyzed with surface EMG, and AR ratio was calculated on the basis of comparison of the surface amplitude of the affected side to that of the nonaffected side. Simultaneously, we measured M-, H-, and T-wave amplitudes and calculated H/M and T/M in the paretic arm. The AR ratio, H/M, and T/M were compared with spasticity as assessed with the modified Ashworth scale (MAS). We repeated the same measurements after median nerve block to examine its effects on the parameters.

RESULTS

The AR ratio correlated significantly with MAS (P < 0.01), whereas H/M and T/M did not. Median nerve block did not alter these relationships.

CONCLUSION

AR, which could be elicited easily in patients with spastic hemiparesis, correlated strongly with spasticity, both before and after the median nerve block. However, the so-called monosynaptic reflex (H- and T reflexes) did not correlate significantly with spasticity. These results indicate that AR and spasticity partially share common pathways.

Muscarinic and Alpha 1-Adrenergic Receptor Binding Characteristics of Saw Palmetto Extract in Rat Lower Urinary Tract

OBJECTIVES

To elucidate the in vitro and ex vivo effects of saw palmetto extract (SPE) on autonomic receptors in the rat lower urinary tract.

METHODS

The in vitro binding affinities for alpha 1-adrenergic, muscarinic, and purinergic receptors in the rat prostate and bladder were measured by radioligand binding assays. Rats received vehicle or SPE (0.6 to 60 mg/kg/day) orally for 4 weeks, and alpha 1-adrenergic and muscarinic receptor binding in tissues of these rats were measured.

RESULTS

Saw palmetto extract inhibited specific binding of [3H]prazosin and [N-methyl-3H]scopolamine methyl chloride (NMS) but not alpha, beta-methylene adenosine triphosphate [2,8-(3)H]tetrasodium salt in the rat prostate and bladder. The binding activity of SPE for muscarinic receptors was four times greater than that for alpha 1-adrenergic receptors. Scatchard analysis revealed that SPE significantly reduced the maximal number of binding sites (Bmax) for each radioligand in the prostate and bladder under in vitro condition. Repeated oral administration of SPE to rats brought about significant alteration in Bmax for prostatic [3H]prazosin binding and for bladder [3H]NMS binding. Such alteration by SPE was selective to the receptors in the lower urinary tract.

CONCLUSIONS

Saw palmetto extract exerts significant binding activity on autonomic receptors in the lower urinary tract under in vitro and in vivo conditions.

Comparative evaluation of central muscarinic receptor binding activity by oxybutynin, tolterodine and darifenacin used to treat overactive bladder

PURPOSE

We characterized muscarinic receptor binding in the mouse cerebral cortex after oral administration of anticholinergic agents used to treat overactive bladder.

MATERIALS AND METHODS

Muscarinic receptors in the mouse cerebral cortex and bladder after oral administration of anticholinergic agents were measured using [(3)H]N-methylscopolamine.

RESULTS

In vitro binding affinities of tolterodine and its metabolite 5-hydroxymethyl metabolite in the mouse cerebral cortex and bladder were considerably greater than those of oxybutynin and darifenacin. Also, muscarinic receptor binding affinity of oxybutynin and its metabolite N-desethyl-oxybutynin in the cerebral cortex compared with that in the bladder was 2 to 3 times higher, whereas that of tolterodine and 5-hydroxymethyl metabolite was approximately 2 times lower. Oral administration of oxybutynin (76.1 micromol/kg), tolterodine (6.31 micromol/kg) and darifenacin (59.1 micromol/kg) showed binding activity that was approximately equal to that of bladder muscarinic receptors. Oral administration of oxybutynin (76.1 micromol/kg) showed significant binding of cerebral cortical muscarinic receptors in mice, as indicated by about a 2-fold increase in K(d) values for specific [(3)H]N-methylscopolamine binding 0.5 and 2 hours later. On the other hand, tolterodine and darifenacin given at oral doses that would exert a similar extent of bladder receptor binding activity as oxybutynin showed only a low level of binding activity of central muscarinic receptors in mice.

CONCLUSIONS

Significant binding of brain muscarinic receptors in mice was observed by the oral administration of oxybutynin but not tolterodine and darifenacin.

Effects of Ginkgo biloba extract on pharmacokinetics and pharmacodynamics of tolbutamide and midazolam in healthy volunteers

This study was undertaken to clarify the influence of repeated oral administration of Ginkgo biloba extract (GBE) on CYP2C9 and CYP3A4. CYP2C9 probe (tolbutamide, 125 mg) and CYP3A4 probe (midazolam, 8 mg) were orally administered to 10 male healthy volunteers before and after GBE intake (360 mg/d) for 28 days, and they received 75 g glucose after the dosing of tolbutamide. Plasma drug concentrations and blood glucose levels were measured. The area under concentration versus time curve (AUC0-infinity) for tolbutamide after GBE intake was slightly but significantly (16%) lower than that before GBE intake. Concomitantly, GBE tended to attenuate AUC0-2 of blood glucose-lowering effect of tolbutamide. AUC0-infinity for midazolam was significantly (25%) increased by GBE intake and oral clearance was significantly (26%) decreased. Thus, it is suggested that the combination of GBE and drugs should be cautious in terms of the potential interactions, especially in elderly patients or patients treated with drugs exerting relatively narrow therapeutic windows.

Urodynamics and bladder muscarinic receptors in rats with cerebral infarction and bladder outlet obstruction

We characterized muscarinic receptor binding and urodynamic parameters in rats with cerebral infarction and chronic bladder outlet obstruction as models of detrusor overactivity. Bladder weight showed little significant difference between the cerebral-infarcted and sham rats, but the bladder weight was about three times greater in the bladder outlet-obstructed rats. Bladder capacity and voided volume were significantly lower (36.7 and 55.1%, respectively) in the cerebral-infarcted than in the sham rats. Involuntary contractions before micturition were seen in the bladder outlet-obstructed rats but not in sham rats. The bladder outlet-obstructed rats showed significant increases (2.65 and 2.57 times, respectively) in bladder capacity and voided volume, compared with those in sham rats. Bmax values for specific [N-methyl-3H]scopolamine ([3H]NMS) binding in the bladder were significantly (34%) increased in the cerebral-infarcted rats compared with sham rats, whereas Kd was unaffected by infarction. On the other hand, there was little significant change in Kd and Bmax for specific [3H]NMS binding in the bladder-obstructed rats compared with sham rats. In conclusion, the present study shows that cerebral infarction but not bladder outlet obstruction in rats causes up-regulation of bladder muscarinic receptors, and that such regulation of bladder muscarinic receptors may be at least partly associated with the symptoms of detrusor overactivity subsequent to cerebral infarction.

In vivo demonstration of M3 muscarinic receptor subtype selectivity of darifenacin in mice

A novel muscarinic receptor antagonist, darifenacin, inhibited specific binding of [N-methyl-(3)H]scopolamine ([(3)H]NMS) in the mouse bladder, submaxillary gland and heart in a concentration-dependent manner. The inhibitory effect was most potent in the submaxillary gland, followed by the bladder and heart. In addition, darifenacin inhibited specific [(3)H]NMS binding in the membranes of CHO-K1 cell lines expressing muscarinic M(2) and M(3) receptor subtypes, and the potency was significantly (22-fold) greater at the M(3) than at the M(2) subtype. At 0.5 to 12 h after oral administration of darifenacin, a significant increase in K(d) values for specific [(3)H]NMS binding was seen in the bladder, submaxillary gland and lung of mice, compared with control values. Also, there was a sustained decrease in the B(max) values in the submaxillary gland. These data suggest that muscarinic receptor binding of oral darifenacin is rapid in onset and of a long duration. On the other hand, oral darifenacin exerted only temporary or little binding of muscarinic receptors in the heart and colon. Pilocarpine-induced salivary secretion in mice was continuously suppressed by oral darifenacin. The time-course of suppression coincided well with that for the muscarinic receptor binding in the submaxillary gland. The antagonistic effect of darifenacin against the dose-response curves for pilocarpine appeared to be insurmountable. In conclusion, the present study has shown that oral darifenacin may exert a pronounced and long-lasting binding of muscarinic receptors in tissues expressing the M(3) subtype.

Serum matrix metalloproteinase-3 levels correlate with disease activity in relapsing-remitting multiple sclerosis

BACKGROUND

Adhesion molecules and matrix metalloproteinases (MMPs) are known to be relevant to the ongoing development and disappearance of areas of demyelination in the white matter of the CNS of multiple sclerosis (MS) patients. This study examined whether serum matrix metalloproteinase-3 (MMP-3) levels correlate with disease activity in MS.

METHODS

Serum MMP-3 levels in 47 consecutive patients with relapsing-remitting MS were measured by immunoassay every 4 weeks over a 15 month period.

RESULTS

During the study period, 48 clinical relapses occurred. Serum MMP-3 levels within 1 month of relapse were significantly higher than during the remission phase. Sequential analysis showed that serum MMP-3 levels had increased transiently at the time of clinical relapse but returned to the normal range within a month.

CONCLUSIONS

Circulatory MMP-3 levels are correlated with disease activity in relapsing-remitting MS. This may contribute to the breakdown of the blood-brain barrier at the time of relapse.

177 ANTHOCYANIN ISOLATED FROM PURPLE SWEET POTATO IMPROVES DEVELOPMENT AND REDUCES OXIDATIVE STRESS OF BOVINE PRE-IMPLANTATION EMBRYOS EXPOSED TO HEAT SHOCK

Development of cleavage-stage pre-implantation embryos is disrupted by exposure to heat shock. Heat shock also increases intracellular reactive oxygen species (ROS) in pre-implantation embryos. Therefore, reduction of intracellular ROS levels might improve the development of heat-shocked embryos. Recently the antioxidative activities of polyphenols have been widely reported to reduce the oxidative stress. In this study, we investigated the effect of purple sweet potato anthocyanin, a kind of polyphenol that is a strong ROS scavenger, on development and intracellular redox status of bovine pre-implantation embryos exposed to heat shock. Experiment 1: In vitro-produced 8-16-cell-stage embryos on Day 2 after fertilization were exposed to 41.5�C for 6 h in CR1aa containing 0, 0.1, 1, and 10 �g/mL anthocyanin at 5% CO2, 5% O2, and 90% N2. After heat shock, embryos were cultured at 38.5�C at 5% CO2, 5% O2 until Day 8. On Day 8, the proportion of embryos developing to the blastocyst stage was evaluated. Blastocyst total cell number and the ratio between inner cell mass and tropheoderm were evaluated by differential staining. The experiment was replicated five times with more than 70 embryos used in each treatment. Experiment 2: Heat shock treatment of in vitro-produced 8-16-cell-stage embryos was carried out as described in experiment 1. After heat shock, intracellular ROS and glutathione (GSH) levels were measured in individual 8-16 cell stage embryos with fluorescent probes (22,72-dichlorodihydrofluorescein diacetate for ROS and CellTracker" Blue (Invitrogen Japan K. K., Tokyo, Japan) for GSH). The fluorescence emissions of each treatment were normalized to those of 8-16 cell stage embryos cultured at 38.5�C without anthocyanin to obtain the relative fluorescence emission. This experiment was replicated four times. Embryos treated with heat stress without anthocyanin (0 �g/mL) showed low development (14.6 � 3.6%) and blastocyst total cell number (88.2 � 9.4). However, embryos treated with 0.1 �g/mL anthocyanin improved development (31.7 � 4.5%, P < 0.05) and increased the total cell number (96.5 � 11.3). The higher concentrations of anthocyanin (1 and 10 �g/mL) did not affect development and cell number. The intracellular ROS levels in heat-shocked embryos were significantly reduced by all concentrations of anthocyanin (P < 0.05). In addition, anthocyanin increased GSH levels at all doses tested (P < 0.05). These results indicate that an appropriate concentration of anthocyanin improves development by regulating intracellular redox balance in bovine embryos exposed to heat shock.

Comparative Evaluation of Exocrine Muscarinic Receptor Binding Characteristics and Inhibition of Salivation of Solifenacin in Mice

Anticholinergic agents such as oxybutynin are clinically useful in the treatment of overactive bladder. However, oral administration of oxybutynin is frequently accompanied by side effects such as dry mouth, and novel bladder-selective anticholinergic agents such as solifenacin and tolterodine are now under development. The aim of the present study was to characterize the suppression of cholinergic salivation and exocrine muscarinic receptor binding of solifenacin on oral administration to mice in comparison with those of oxybutynin. Results showed that both drugs produced a significant increase in K(d) values for specific [N-Methyl-(3)H]scopolamine methyl chloride ([(3)H]NMS) binding in the mouse submaxillary gland, compared with control values. However, this enhancement in K(d) values was significantly smaller with solifenacin than with oxybutynin. Moreover, the inhibitory effect of solifenacin on pilocarpine-induced salivary secretion was significantly weaker than that of oxybutynin. Solifenacin dissociated more readily from muscarinic receptors in the mouse submaxillary gland than oxybutynin. In conclusion, the present study indicates that the weak suppression of cholinergic salivation by solifenacin compared with oxybutynin may be partially attributed to its relatively fast dissociation kinetics from exocrine muscarinic receptors.

Human Muscarinic Receptor Binding Characteristics of Antimuscarinic Agents to Treat Overactive Bladder

PURPOSE

We characterized the binding affinities of several antimuscarinic agents in human muscarinic receptors.

MATERIALS AND METHODS

Competitive inhibitory effects of antimuscarinic agents on specific NMS [H] (PerkinElmer Life Sciences, Boston, Massachusetts) binding were examined in human tissue homogenates and in CHO-K1 cell membranes expressing human muscarinic receptor subtypes.

RESULTS

Oxybutynin, propiverine, tolterodine, the respective metabolites DEOB, DPr-P-4(N-->O) and 5-HM, and darifenacin inhibited in concentration dependent fashion specific [(3)H]NMS binding in homogenates of the human bladder and parotid gland as well as in membranes of CHO-K1 cell lines expressing human muscarinic M(1) to M(5) receptor subtypes. Based on inhibition constant values the inhibitory effects of tolterodine, 5-HM and DPr-P-4(N-->O) were 1.4 to 1.7 times greater in the bladder than in the parotid gland, whereas the inhibitory effects of oxybutynin, DEOB, propiverine and darifenacin were 2 to 10 times greater in the parotid gland. Consequently tolterodine, 5-HM and DPr-P-4(N-->O) compared with oxybutynin, DEOB, propiverine and darifenacin were found to show 3 to 4 times greater affinity to muscarinic receptors in the human bladder than in the parotid gland. Tolterodine and 5-HM were 2-fold more potent for inhibiting specific [(3)H]NMS binding at cell membranes expressing the M(2) vs the M(3) subtype. Conversely oxybutynin, DEOB, propiverine, DPr-P-4(N-->O) and darifenacin showed 2 to 22 times higher affinity to the M(3) than to the M(2) subtype.

CONCLUSIONS

Compared with oxybutynin, tolterodine, 5-HM and DPr-P-4(N-->O) may bind more selectively to muscarinic receptors in the human bladder than in the parotid gland.

Characterization of muscarinic receptor binding and inhibition of salivation after oral administration of tolterodine in mice

The current study was undertaken to characterize the effects of oral administration of tolterodine on muscarinic receptor binding in the bladder and submaxillary gland and on salivation in mice. In the in vitro experiment, tolterodine and its metabolite (5-hydroxymethyl metabolite: 5-HM) competed concentration-dependently with [N-methyl-(3)H]-scopolamine ([(3)H]NMS) in the mouse bladder, submaxillary gland and heart, and the potencies of both agents were greater than that of oxybutynin. After oral administration of tolterodine (6.31, 21.0 micromol/kg) and oxybutynin (76.1 micromol/kg), there was a dose and time-dependent increase in K(d) values for specific [(3)H]NMS binding in the bladder, prostate, submaxillary gland, heart, colon and lung, compared with control values, suggesting significant muscarinic receptor binding in each tissue. The K(d) increase in each tissue by oral oxybutynin reached a maximum value of 0.5 h after oral administration and then rapidly declined, while that by tolterodine was greatest 2 h after the administration and it was maintained for at least 6 or 12 h, depending on the dose and on the tissue. Thus, muscarinic receptor binding of oral tolterodine was slower in onset and of a longer duration than that of oxybutynin. Also, oral oxybutynin showed relatively greater receptor binding in the submaxillary gland as compared with other tissues, but such high selectivity to the exocrine gland muscarinic receptors was not observed by oral tolterodine. Oral administration of tolterodine and oxybutynin reduced significantly the pilocarpine-induced salivary secretion in mice, and the attenuation of oral tolterodine appeared more slowly and it was more persistent than that of oral oxybutynin. The antagonistic effect of oral tolterodine on the dose-response curves to pilocarpine was significantly weaker than that of oxybutynin. These data suggest that oral tolterodine, compared with the case of oral oxybutynin, binds more selectively to muscarinic receptors in the mouse bladder than in the submaxillary gland, which may be advantageous in treating patients with overactive bladder.

Advantages for transdermal over oral oxybutynin to treat overactive bladder: Muscarinic receptor binding, plasma drug concentration, and salivary secretion

To clarify pharmacological usefulness of transdermal oxybutynin in the therapy of overactive bladder, we have characterized muscarinic receptor binding in rat tissues with measurement of plasma concentrations of oxybutynin and its metabolite N-desethyl-oxybutynin (DEOB) and salivation after transdermal oxybutynin compared with oral route. At 1 and 3 h after oral administration of oxybutynin, there was a significant increase in apparent dissociation constant (Kd) for specific [N-methyl-3H]scopolamine ([3H]NMS) binding in the rat bladder, submaxillary gland, heart, and colon compared with control values. Concomitantly, submaxillary gland and heart showed a significant decrease in maximal number of binding sites (Bmax) for [3H]NMS binding, which lasted until 24 h. Transdermal application of oxybutynin caused dose-dependent increases in Kd values for specific [3H]NMS binding in rat tissues. The increment of Kd values by transdermal oxybutynin was dependent on the application time. Plasma concentrations of oxybutynin and DEOB peaked at 1 h after oral oxybutynin. In contrast, plasma concentrations of oxybutynin increased slowly, depending on the transdermal application time of this drug until 12 h. Suppression of pilocarpine-induced salivation in rats due to transdermal oxybutynin was significantly weaker and more reversible than that by oral oxybutynin, which abolished salivary secretion. The present study has shown that transdermal oxybutynin binds significantly to rat bladder muscarinic receptors without producing both long-lasting occupation of exocrine receptors and cessation of cholinergic salivation evoked by oral oxybutynin. Thus, the present study provides further pharmacological basis for advantage of transdermal over oral oxybutynin in the therapy of overactive bladder.

Muscarinic receptor binding, plasma concentration and inhibition of salivation after oral administration of a novel antimuscarinic agent, solifenacin succinate in mice

1 A novel muscarinic receptor antagonist, solifenacin succinate, inhibited specific binding of [N-methyl-(3)H]-scopolamine ([(3)H]-NMS) in the mouse bladder, submaxillary gland and heart in a concentration-dependent manner. This inhibitory effect was greatest in the submaxillary gland, followed by the bladder and heart. 2 After oral administration of oxybutynin (76.1 micromol kg(-1)) or solifenacin (62.4, 208 micromol kg(-1)), a significant dose- and time-dependent increase in K(D) values for specific [(3)H]-NMS binding was seen in the bladder, prostate, submaxillary gland, heart, colon and lung, compared with control values. The increase in K(D) induced by oxybutynin in each tissue reached a maximum 0.5 h after oral administration and then rapidly declined, while that induced by solifenacin was greatest 2 h after administration and was maintained for at least 6 or 12 h, depending on the dose. The muscarinic receptor binding of oral solifenacin was slower in onset and of a longer duration than that of oxybutynin. 3 Plasma concentrations of oxybutynin and its active metabolite (N-desethyl-oxybutynin, DEOB) were maximum 0.5 h after its oral administration and then declined rapidly. Oral solifenacin persisted in the blood for longer than oxybutynin. 4 Pilocarpine-induced salivary secretion in mice was significantly reduced by oral administration of solifenacin and was completely abolished 0.5 h after oral oxybutynin. Although the suppression induced by solifenacin was more persistent than that due to oxybutynin, the antagonistic effect of solifenacin on the dose-response curves to pilocarpine was significantly weaker than that of oxybutynin. It is concluded that oral solifenacin persistently binds to muscarinic receptors in tissues expressing the M(3) subtype, such as the bladder.

In vivo demonstration of muscarinic receptor binding activity of N-desethyl-oxybutynin, active metabolite of oxybutynin

The present study was undertaken to characterize in vivo muscarinic receptor binding of N-desethyl-oxybutynin (DEOB), active metabolite of oxybutynin (anticholinergic agent), in the bladder, submaxillary gland, heart and colon of rats, in relation to the plasma concentrations and inhibition of salivation. In the in vitro experiment, DEOB, as well as oxybutynin, inhibited the concentration-dependently specific [3H]N-methylscopolamine (NMS) binding in rat tissues and the affinity of DEOB in the rat bladder, submaxillary gland and colon was significantly (about 2 times) greater than that of oxybutynin. Following i.v. injection of DEOB (2.73-27.3 micromol/kg), there were dose- and time-dependent increases in the apparent dissociation constant (Kd) for specific [3H]NMS binding in the bladder, submaxillary gland, heart and colon of rats, compared with control values, and the effect was similar to that by i.v. injection of oxybutynin (2.54-25.4 micromol/kg). Plasma concentrations of DEOB and oxybutynin in these rats showed dose- and time-dependent increases. The pilocarpine-induced salivary secretion in rats was equipotently reduced by the i.v. injection of DEOB and oxybutynin. In conclusion, it has been shown that intravenously injected DEOB, as well as oxybutynin, binds significantly to muscarinic receptors in rat tissues including the bladder and salivary gland and the receptor binding activity of DEOB is roughly similar to that of oxybutynin.

EFFECTS OF SAW PALMETTO EXTRACT ON MICTURITION REFLEX OF RATS AND ITS AUTONOMIC RECEPTOR BINDING ACTIVITY

PURPOSE

We examined the effects of saw palmetto extract (SPE) on the rat micturition reflex and on autonomic receptors in the lower urinary tract.

MATERIALS AND METHODS

The effect of SPE was examined on cystometrograms of anesthetized rats induced by intravesical infusion of saline or 0.1% acetic acid. SHR/NDmc-cp (cp/cp) rats received repeat oral administration of SPE and nighttime urodynamic function was determined. The autonomic receptor binding activity of SPE in the rat bladder and prostate was examined by radioligand binding assay.

RESULTS

Intraduodenal administration of SPE (60 mg/kg) in anesthetized rat cystometry caused a significant increase in the micturition interval, micturition volume and bladder capacity during intravesical saline infusion. Also, similar administration of SPE at doses of 12 and 20 mg/kg significantly reversed the shortened micturition interval as well as the decreased micturition volume and bladder capacity due to 0.1% acetic acid infusion in a dose dependent manner. In conscious SHR/NDmc-cp (cp/cp) rats repeat oral administration of SPE (6 mg/kg daily) constantly increased the micturition interval and concomitantly decreased voiding frequency. SPE inhibited specific binding of [H]NMS ([N-methyl-H]scopolamine methyl chloride) (bladder) and [H]prazosin (prostate) with IC50 values of 46.1 and 183 microg/ml, respectively.

CONCLUSIONS

SPE significantly alleviates urodynamic symptoms in hyperactive rat bladders by increasing bladder capacity and subsequently prolonging the micturition interval. Our data may support the clinical efficacy of SPE for the treatment of lower urinary tract symptoms.

Quantitative analysis of binding parameters of [3H]N-methylscopolamine in central nervous system of muscarinic acetylcholine receptor knockout mice

We have studied binding parameters (Kd, Bmax) of [3H]N-methylscopolamine ([3H]NMS) in various brain regions and spinal cord of wild-type (WT) and muscarinic acetylcholine receptor (mAChR) subtype (M1-M5) knockout (KO) mice. In the M1-M4 KO mice, the number of [3H]NMS binding sites (Bmax) was decreased throughout the central nervous system (CNS) with significant regional differences. Our results collectively suggest that M1 receptor was present in a relatively high density in the cerebral cortex and hippocampus, and the densities of M1 and M4 subtypes were highest in the corpus striatum. M2 receptor appeared to be the major subtype in the thalamus, hypothalamus, midbrain, pons-medulla, cerebellum and spinal cord. These findings may contribute significantly not only to the further understanding of the physiological roles of mAChR subtypes in the central cholinergic functions, but also to the development of selective therapeutic agents targeting specific subtype.

Natural vanadium-containing Mt. Fuji ground water improves hypo-activity of liver insulin receptor in Goto-Kakisaki rats

After daily treatments with Mt. Fuji ground water containing natural vanadium (approximately 65 microg/l) at doses of 0.53 microg/kg/day for 12 weeks, blood glucose (BG), serum hemoglobin A1C (HbA1C) levels and insulin secretion from the pancreas of Goto-Kakisaki (GK) rats, a genetic model of Type 2 diabetes, were improved. In GK rat liver insulin receptors, the binding properties of [125I] insulin, and the activities of insulin receptor beta subunit and primary insulin-like growth factor-1beta all recovered to normal levels of those found in Wistar rats. These results suggest that daily treatment with small concentrations of natural vanadium improves hyperglycemia by ameliorating liver insulin receptor activity.

DEMONSTRATION OF BLADDER SELECTIVE MUSCARINIC RECEPTOR BINDING BY INTRAVESICAL OXYBUTYNIN TO TREAT OVERACTIVE BLADDER

PURPOSE

The current study was done to elucidate the in vivo mechanism of action of intravesical instillation of oxybutynin to treat overactive bladder.

MATERIALS AND METHODS

In rats receiving oral and intravesical oxybutynin we measured muscarinic receptors in the bladder and other tissues by radioligand binding assay using [3H]NMS ([N-methyl-3H] scopolamine methyl chloride) with the simultaneous measurement of plasma concentrations of oxybutynin and its active metabolite N-desethyl-oxybutynin. Pilocarpine induced salivary secretion was also measured.

RESULTS

Following oral administration of oxybutynin there was a significant increase in the apparent dissociation constant (Kd) for specific [3H]NMS binding in the bladder, submaxillary gland, heart and colon of rats at 1 and 3 hours with a consistent decrease in the maximal number of binding sites (Bmax) in the submaxillary gland. Furthermore, a marked and prolonged decrease in pilocarpine induced salivary secretion in rats was observed by oral oxybutynin. In contrast, intravesical instillation of oxybutynin produced a significant increase in Kd for specific [3H]NMS binding in the bladder of rats at 0.5 to 4 hours later and also in the submaxillary gland only at 0.5 hours later. The enhancement in Kd was much larger and longer lasting in the bladder than in the submaxillary gland. Moreover, intravesical oxybutynin had little muscarinic receptor binding activity in the heart and colon, and little significant suppression of pilocarpine induced salivation in rats. The plasma concentrations of oxybutynin and N-desethyl-oxybutynin were much higher in rats receiving oxybutynin orally than intravesically.

CONCLUSIONS

Intravesical oxybutynin in rats may cause selective binding of bladder muscarinic receptors via a direct local effect, while oral oxybutynin may exert predominant binding of salivary gland receptors.

Functional analysis of muscarinic acetylcholine receptors using knockout mice

Because of the low selectivity of available ligands, pharmacological approaches to elucidate the functional difference among muscarinic acetylcholine receptor (mAChR) subtypes have been problematic. As an alternative approach, we have established a series of mutant mouse lines deficient in each mAChR subtype (mAChR KO mice). The systematic analyses of these mice have been useful in revealing the functional difference among mAChR subtypes. Here, we review our prior research on these mutant mice and also some notable findings reported by other research groups.