Evaluation of the direct protective effects of Canagliflozin on the Isoproterenol-induced cell injury in rat cardiomyocytes

Background

Sodium-glucose cotransporter-2 (SGLT2) inhibitors are agents that act by inhibiting glucose and sodium reabsorption in the proximal renal tubule which promotes urinary glucose excretion. More recently, significant benefit data of SGLT2 inhibitors in patients with heart failure, independent of the presence of type 2 diabetes has been reported. We have previously demonstrated that Canagliflozin (Cana), a SGLT2 inhibitor, reduced the ventricular effective refractory period in isoproterenol (ISP)-induced myocardial injury rat model accompanied with the suppression of reactive oxygen species and the elevation of ketone bodies, suggesting the effect of Cana on electrical cardiac remodeling. The direct effect of Cana to the cardiomyocytes and its underlying molecular mechanism was remained to be clarified. We therefore established an ISP-induced neonatal rat ventricular cardiomyocyte (NRVCM) in vitro model, pretreated with Cana and/or ketone bodies.

Methods

Primary NRVCM were isolated from Wistar rats, were pretreated by Cana with or without βOHB (the most abundant ketone body in circulation), followed by a stimulation of ISP (10μM). Cells without drug or ketone body pretreatment were used as control. We then analyzed its effect on cell viability, apoptosis, and mitochondrial membrane potential using MTT assay, TUNEL assay, and mitochondrial membrane potential assay, respectively. MTT assay was also performed with or without PI3k inhibitor, LY294002. The end-labeling of DNA fragmentation were labelled with FITC, followed by the nuclei counterstain with DAPI and were observed with confocal microscope. The apoptotic index was defined as the percentage of TUNEL positive cells / total nuclei.

Results

Cana rescued the reduction of NRVCM cell viability induced by ISP stimulation for 24 hours which was inhibited by LY294002 compared to cells without pretreatment. Interestingly, pretreatment of βOHB with or without Cana improved also the NRCVM cell viability whereas there was no significant difference between these two conditions or with cells treated with Cana only, suggesting the direct protective effect of Cana. In 48 hours of ISP stimulation, the apoptotic index intends to decrease in Cana and/or βOHB compared to cells without pretreatment (Figure 1). Although the mitochondrial function was maintained in Cana-pretreated cells compared to cells without pretreatment, there was no significant difference in βOHB-pretreated cells.

Conclusions

Cana has a direct protective effect on cardiomyocytes cell viability, apoptosis as well as the mitochondrial function impaired by ISP through the cell survival signaling PI3K/Akt pathway. This brings a new insight to the therapeutic target of cardiovascular disease.

Funding Acknowledgement

Type of funding sources: None.

Prognostic impact of atrial fibrillation under oral anticoagulation therapy in patients with type B acute aortic dissection

Background

Patients with acute aortic dissection (AAD) sometimes are complicated with atrial fibrillation (AF). However, the impact of AF and the use of oral anticoagulation (OAC) on the prognosis of AAD remains unclear. In this study, we evaluated the prognostic impact of AF and OAC therapy in patients with type B AAD.

Methods

Consecutive patients diagnosed with type B AAD between January 2010 and December 2020 in our university hospital were retrospectively analyzed. All patients were divided into 2 groups based on the concomitance with or without AF. The primary endpoint was set as major adverse cardiovascular events (MACEs), including all-cause death, enlargement of aortic diameter, aortic ruptures, and cerebral infarction. Kaplan-Meier survival curves were constructed, and Cox proportional hazards analysis was performed to identify independent predictors of clinical events at 1 year.

Results

A total of 146 patients diagnosed with type B AAD were enrolled, with a mean age of 66±12 years, and 81% of male. Thirty-two patients (22%) experienced MACEs during 272±142 days-observation. Concomitant AF was observed in 27 patients (18%). In the Kaplan-Meier curve analysis, the patients with AF showed significantly higher events than those without AF (log-lank p<0.001). In the multivariate Cox proportional hazards models, presence of AF (HR: 2.402, 95% CI: 1.099–4.978 p=0.029), maximum descending aorta diameter (HR: 1.0366, 95% CI: 1.005–1.064 p=0.023), and age>75 years (HR: 2.635, 95% CI: 1.268–5.388 p=0.011) were independent predictors of MACEs. Regarding OAC in patients with AF, Kaplan-Meier analysis showed that usage of OAC was associated with a higher incidence of MACEs than those without (log-rank, p=0.036)

Conclusion

Presence of AF, enlargement of descending aorta diameter, and age were independent predictors of future MACEs in patients with type B AAD. Additionally, usage of OAC is associated with MACEs in patients with type B AAD complicated with AF.

Funding Acknowledgement

Type of funding sources: None.

Aspirin vs. P2Y12 inhibitors with anticoagulation therapy for atrial fibrillation: insights from the AFIRE trial

Background

Patients with coronary artery disease (CAD) and atrial fibrillation (AF) can be treated with multiple antithrombotic therapies including antiplatelets and oral anticoagulants; however, this has the potential to increase bleeding risk.

Purpose

This sub-analysis aimed to evaluate the efficacy and safety of P2Y12 inhibitors and aspirin in patients also receiving oral anticoagulant therapy.

Methods

We evaluated patients from the Atrial Fibrillation and Ischemic Events with Rivaroxaban in Patients with Stable Coronary Artery Disease (AFIRE) trial who received combination therapy (rivaroxaban plus a single antiplatelet agent). The choice of antiplatelets was left to the physician's discretion. The primary efficacy endpoint was a composite of stroke, systemic embolism, myocardial infarction, unstable angina requiring revascularization, and death from any cause. The primary safety endpoint was major bleeding according to the International Society on Thrombosis and Haemostasis criteria.

Results

A total of 1,075 patients were included (P2Y12 inhibitor group, n=297; aspirin group, n=778). Approximately 60% of patients were administered proton pump inhibitors (PPIs), and there was no significant difference in PPI use in the P2Y12 inhibitor and aspirin groups. Regarding the primary efficacy endpoint, there was no significant difference between the P2Y12 inhibitor and aspirin groups (hazard ratio, 1.31; 95% confidence interval, 0.88–1.94; p=0.178). Likewise, the primary safety endpoint was not different between the groups (hazard ratio, 0.79; 95% confidence interval, 0.43–1.47; p=0.456). In the detailed subgroup analysis, there were no differences in the efficacy and safety endpoints.

Conclusions

There were no significant differences between P2Y12 inhibitors and aspirin in cardiovascular events in patients with AF and stable CAD taking rivaroxaban in the chronic phase.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The Japan Cardiovascular Research Foundation based on a contract with Bayer Yakuhin, Ltd. Summary of this study

Catheter contact angle influences local impedance drop during radiofrequency catheter ablation: insight from a porcine experimental study

Background

Local impedance (LI) at a distal tip of the ablation catheter can indirectly measure catheter contact and tissue temperature during radiofrequency catheter ablation (RFCA). LI decreases by RFCA, and a degree of LI drop is correlated with lesion size. However, data on the effects of catheter contact angle on lesion size and LI drop were scarce. This study aimed to evaluate the influence of catheter contact angle on lesion size and LI drop in a porcine experimental study.

Methods

Lesions were created on porcine myocardial left ventricles by the LI-sensing ablation catheter (IntellaNav MiFi OI®). Contact force (CF) was measured using pressure to current transducer (load cell). Radiofrequency ablation was performed with a power of 30 Watt and a duration of 30 seconds. CF (0g, 5g, 10g, 20g, and 30g) and catheter angle (30°, 45°, and 90°) were changed in each set (total 120 lesions, n=8 each). LI rise, LI drop by RF application, and lesion size (maximum lesion width, maximum surface width, and maximum lesion depth) were evaluated.

Results

There was no angular dependence in LI rise in all CF. The values of LI rise increased as CF increased. The LI drop also increased as CF increased in all contact angles. Regarding the difference of catheter angles, LI drop with 90° was lower than those with 30° and 45°in CF 10g, 20g, and 30g, respectively. Maximum lesion width and surface width were larger in 30° and 45° than those in 90°, whereas there were no differences in maximum lesion depth.

Conclusion

LI drop in 90° were significantly lower than those in 45° and 30°. Although lesion depths were not different among the three angles, the absolute values of LI drop were different. Caution should be exercised to comprehend the LI drop with catheter angles.

Funding Acknowledgement

Type of funding sources: None.

Novel risk factor for fatal arrhythmia in Brugada syndrome

Background

Brugada syndrome (BrS) is a genetic disease associated with increased risk of ventricular fibrillation (VF)/ventricular tachycardia (VT). The VF/VT in BrS occurs more frequently during a night time or at a rest with parasympathetic nerve activation. Some risk factors of VF/VT occurrence in BrS have been elucidated, however, it remains controversial about risk stratification. Salusin-β is an endogenous bioactive peptide that systemically exerts rapid and profound hypotensive and bradycardic activities and parasympathomimetic hemodynamic actions in vivo. Previous reports suggested that salusin-β is suppressed following physiological parasympathetic stimulation and appears to constitute a negative feedback relationship with the parasympathetic nervous system.

Purpose

We hypothesized that salusin-β is associated with the occurrence of VF/VT in BrS.

Methods

The study population consisted of 26 BrS patients with newly implantation of implantable cardioverter defibrillator (ICD) during 2003–2008. In all patients, salusin-β was measured in supine position after 20 minute rest. The date of salusin-β sampling was set as the registration point for this study. The VF/VT was defined as any episode of fatal ventricular tachyarrhythmia or any appropriate shock. In accordance with the presence or absence of VF/VT events within 5 years, all patients were divided into VF/VT group (n=6) and non-VF/VT group (n=20).Various clinical parameters were compared between the two groups. For analysis of autonomic nervous function, heart rate variability (HRV) and pupil function were evaluated.

Results

The mean age was 54±17 years old. There is no differences between the two groups in clinical parameters. In analysis of HRV, the high-frequency component (0.15–0.40 Hz; HF), low frequency component (0.04–0.15 Hz; LF) and the LF/HF ratio were analyzed over 24 h. LF/HF ratio was significantly lower over 24h in VF/VT groups in comparison with non-VF/VT groups [day-time; 1.8 (1.2–5.6) vs. 5.2 (3.4–8.8), p=0.048, night-time; 1.2 (1.1–1.3) vs. 3.9 (2.5–8.7), p=0.003]. Furthermore, in analysis of pupil function, right/left miosis ratio was higher in VT/VF groups in comparison with non-VT/VF groups [right pupil; 0.39 (0.37–0.59) vs. 0.34 (0.28–0.38), p=0.035, left pupil; 0.43 (0.36–0.50) vs. 0.33 (0.28–0.40), p=0.049]. In plasma total salusin-β levels, the VF/VT groups exhibited significantly lower than non-VF/VT groups (55.2±14.6 vs. 73.2±22.2, p=0.039, Figure).

Conclusions

Salusin-β was associated with the occurrence of VF/VT in Brugada syndrome. Salusin-β might be useful to identify high-risk patients for the occurrence of VT/VF events in Brugada syndrome.

Funding Acknowledgement

Type of funding source: None

Remote monitoring can predict lethal arrhythmic events through time-domain analysis of heart rate variability in patients with implantable cardioverter defibrillator

Background

We prospectively collected device and heart rate data, i.e. heart rate variability (HRV), through remote monitoring (RM) of patients with implantable cardioverter defibrillator (ICD). Several studies have demonstrated usefulness of RM in implanted device patients, however, reports concerning the predictors of lethal ventricular arrhythmias are limited.

Purpose

The objective was to identify the predictors of lethal arrhythmic events (VT/VF).

Methods

Thirty-three patients (mean age: 50 years) with ICDs [with functionality of HRV analysis] were divided into 2 groups [VT/VF(+), VT/VF(−)]. Clinical, device (ventricular lead impedance; amplitude of ventricular electrogram), and HRV data were compared between the 2 groups. As the index of time-domain HRV analysis, NN intervals-index (SDNNi) was calculated for every 5 minutes, and the mean, maximum, and minimum SDNNi during the 24-hour period were used.

Results

During the observation period (median 12 months), 10 patients experienced VT/VF events. In HRV data, the mean, max, and min SDNNi were higher in VT/VF(+) than VT/VF(−) group (132.9±9.3 v.s. 93.5±6.1, p=0.0013; 214.6±10.6 v.s. 167.0±7.0, p=0.0007; 71.2±7.5 v.s. 43.9±4.9, p=0.0047). The other parameters did not exhibit significant difference. On logistic regression analysis, the mean SDNNi of 100.1, max SDNNi of 185.0 and min SDNNi of 52.0 as cut-off values for prediction of VT/VF event demonstrated significant receiver operating characteristics (ROC) curves (AUC=0.86, p=0.0007; AUC=0.84, p=0.0005; AUC=0.78, p=0.0030). Furthermore, in cases of VT/VF(+) group, the max ΔSDNNi, i.e., difference from baseline SDNNi, and min ΔSDNNi in 7 and 28 days preceding VT/VF events exhibited time course changes in comparison with baseline values. They were significant predictors of VT/VF events (max ΔSDNNi cut-off: 46.8, AUC=0.91, p=0.0002; min ΔSDNNi cut-off: −42.4, AUC=0.88, p=0.0014).

Conclusion

Time-domain analysis of HRV through RM may help identify patients at high risk of lethal arrhythmic events, and predict occurrence of such arrhythmic events.

Funding Acknowledgement

Type of funding source: None

P3106Atrial fibrillation is not associated with the responses to exercise training in heart failure patients with preserved ejection fraction

Background

Atrial fibrillation (AF) is known as a common arrhythmia in heart failure patients with preserved left ventricular ejection fraction (HFpEF). Several studies have reported that HFpEF patients with AF show lower exercise tolerance and poorer prognosis as compared with those with sinus rhythm (SR). On the other hand, exercise training is documented to improve peripheral muscle function and exercise tolerance in HFpEF patients. However, the relationship between AF status and outcomes due to exercise training is still unclear in these patients.

Purpose

We aimed to investigate the influence of AF on the responses to outcomes with exercise training in HFpEF patients.

Methods

We studied 426 patients with HFpEF who received 5-month cardiac rehabilitation including exercise training during hospitalization and after hospital discharge. As clinical characteristics, we obtained body mass index, disease aetiology, comorbidity conditions, blood examination and echocardiographic variables from medical records. We also measured isometric quadriceps strength (QS) and 6-minute walk distance (6MWD) as peripheral muscle strength and exercise tolerance, respectively. The QS and 6MWD were assessed at hospital discharge as the baseline and 5 months later. AF status was determined by the presence on electrocardiogram at baseline 6MWD or medical history of AF during hospitalization. In statistical analysis, we compared baseline clinical characteristics, QS and 6MWD between the rhythm status (SR group or AF group). We also examined the changes in QS and 6MWD from baseline to the 5-month observation period (ΔQS and Δ6MWD) and compared them between the 2 groups using analysis of covariance with adjustment for baseline clinical confounding factors.

Results

At baseline, 289 patients (68%) were in SR, and 111 patients (26%) had AF. The AF was associated significantly with older age (P<0.001) and lower levels of estimated glomerular filtration rate (P=0.013), QS (P<0.001) and 6MWD (P<0.001) at baseline. The QS increased significantly from 25.2±11.0 kg at baseline to 30.8±13.0 kg after 5-month cardiac rehabilitation in the SR group, and from 21.1±8.3 kg to 26.0±9.4 kg in the AF group (P<0.001, respectively). The 6MWD also increased significantly from 394.8±129.2 to 463.5±133.5 meters in the SR, and from 343.7±107.9 to 403.0±114.5 meters in the AF (P<0.001, respectively). There were no significant differences in ΔQS and Δ6MWD between the SR and AF groups even after adjustment for clinical confounding factors including baseline QS or 6MWD (Figure).

Conclusions

The AF status in HFpEF patients was associated with older age, lower peripheral muscle function and also lower exercise tolerance at baseline, but not associated with the responses to exercise training.

Acknowledgement/Funding

JSPS KAKENHI JP16K16442

P1495Energy loss by right ventricular pacing: normal left ventricular function vs. hypertrophic cardiomyopathy

Background

Right ventricular (RV) pacing causes left ventricular (LV) dysfunction. On the other hand, RV pacing for hypertrophic obstructive cardiomyopathy (HOCM) is an established treatment. LV flow energy loss (EL) is a new hemodynamic index for assessing cardiac function. However, the impact of RV pacing on EL remains unknown.

Objective

The objective of this study was to investigate the EL by RV pacing on normal LV function and hypertrophic cardiomyopathy (HCM).

Methods

A total of 28 patients underwent echocardiography for EL assessment under AAI (without RV pacing) and DDD (with all RV pacing) mode. Among them, 16 were sick sinus syndrome (SSS) patients with normal LV function, and 12 were HCM patients. EL was calculated from color Doppler images using a vector flow mapping.

Results

There were no significant difference in patients' background parameters between the SSS and the HCM groups. In the SSS group, mean systolic EL was significantly increased from AAI to DDD mode (14.9 to 19.2 mW/m, P<0.01, Panel A), whereas diastolic EL was not changed from AAI to DDD mode (22.3 to 18.8 mW/m, P=0.12). In the HCM group, systolic mean EL was significantly decreased from AAI to DDD mode (29.9 to 22.5 mW/m, P<0.01, Panel B) irrespectively of with or without LV outflow obstruction, whereas diastolic mean EL was not changed from AAI to DDD mode (28.6 to 24.3 mW/m, P=0.47).

Change of flow energy loss

Conclusion

RV pacing increased mean systolic EL in normal LV function, but decreased in HCM with or without LV outflow obstruction. In the patients with HCM, the impact of RV pacing on EL is different compared with normal LV function.

Review of lattice results concerning low-energy particle physics: Flavour Lattice Averaging Group (FLAG)

We review lattice results related to pion, kaon, D- and B-meson physics with the aim of making them easily accessible to the particle-physics community. More specifically, we report on the determination of the light-quark masses, the form factor [Formula: see text], arising in the semileptonic [Formula: see text] transition at zero momentum transfer, as well as the decay constant ratio [Formula: see text] and its consequences for the CKM matrix elements [Formula: see text] and [Formula: see text]. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of [Formula: see text] and [Formula: see text] Chiral Perturbation Theory. We review the determination of the [Formula: see text] parameter of neutral kaon mixing as well as the additional four B parameters that arise in theories of physics beyond the Standard Model. The latter quantities are an addition compared to the previous review. For the heavy-quark sector, we provide results for [Formula: see text] and [Formula: see text] (also new compared to the previous review), as well as those for D- and B-meson-decay constants, form factors, and mixing parameters. These are the heavy-quark quantities most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. Finally, we review the status of lattice determinations of the strong coupling constant [Formula: see text].

Review of lattice results concerning low-energy particle physics

We review lattice results related to pion, kaon, [Formula: see text]- and [Formula: see text]-meson physics with the aim of making them easily accessible to the particle-physics community. More specifically, we report on the determination of the light-quark masses, the form factor [Formula: see text], arising in semileptonic [Formula: see text] transition at zero momentum transfer, as well as the decay-constant ratio [Formula: see text] of decay constants and its consequences for the CKM matrix elements [Formula: see text] and [Formula: see text]. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of [Formula: see text] and [Formula: see text] Chiral Perturbation Theory and review the determination of the [Formula: see text] parameter of neutral kaon mixing. The inclusion of heavy-quark quantities significantly expands the FLAG scope with respect to the previous review. Therefore, we focus here on [Formula: see text]- and [Formula: see text]-meson decay constants, form factors, and mixing parameters, since these are most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. In addition we review the status of lattice determinations of the strong coupling constant [Formula: see text].

Determination of the chiral condensate from (2+1)-flavor lattice QCD

We perform a precise calculation of the chiral condensate in QCD using lattice QCD with 2+1 flavors of dynamical overlap quarks. Up and down quark masses cover a range between 3 and 100 MeV on a 16{3}x48 lattice at a lattice spacing approximately 0.11 fm. At the lightest sea quark mass, the finite volume system on the lattice is in the regime. By matching the low-lying eigenvalue spectrum of the Dirac operator with the prediction of chiral perturbation theory at the next-to-leading order, we determine the chiral condensate in (2+1)-flavor QCD with strange quark mass fixed at its physical value as Sigma;{MS[over ]}(2 GeV)=[242(04)(+19/-18) MeV]{3} where the errors are statistical and systematic, respectively.

S parameter and pseudo Nambu-Goldstone boson mass from lattice QCD

We present a lattice calculation of L10, one of the low-energy constants in chiral perturbation theory, and the charged-neutral pion squared-mass splitting, using dynamical overlap fermion. The exact chiral symmetry of the overlap fermion allows us to reliably extract these quantities from the difference of the vacuum polarization functions for vector and axial-vector currents. In the context of the technicolor models, these two quantities are read as the S parameter and the pseudo Nambu-Goldstone boson mass, respectively, and play an important role in discriminating the models from others. This calculation can serve as a feasibility study of the lattice techniques for more general technicolor gauge theories.

Convergence of the chiral expansion in two-flavor lattice QCD

We test the convergence property of the chiral perturbation theory using a lattice QCD calculation of pion mass and decay constant with two dynamical quark flavors. The lattice calculation is performed using the overlap fermion formulation, which realizes exact chiral symmetry at finite lattice spacing. By comparing various expansion prescriptions, we find that the chiral expansion is well saturated at the next-to-leading order for pions lighter than approximately 450 MeV. Better convergence behavior is found, in particular, for a resummed expansion parameter xi, with which the lattice data in the pion mass region 290-750 MeV can be fitted well with the next-to-next-to-leading order formulas. We obtain the results in two-flavor QCD for the low energy constants l[over ]_{3} and l[over ]_{4} as well as the pion decay constant, the chiral condensate, and the average up and down quark mass.

A cyclosporin A/maltosyl-alpha-cyclodextrin complex for inhalation therapy of asthma

The inhalation of cyclosporin (Cs)A to the lung is limited by its hydrophobic properties. In order to improve the poor solubility of CsA, cyclodextrin (CD) was evaluated for its suitability for dry powder inhaler formation, and the benefit of an inhaled CsA/CD complex in vivo was demonstrated. The solubilising effect of CDs on CsA was measured by high-performance liquid chromatography. Ciliostatic activity and haemolysis were determined to assess some safety profiles of CDs. The efficacy of an inhaled CsA/CD complex was evaluated by eosinophil infiltration into the bronchoalveolar lavage fluid in actively sensitised mice. CDs markedly improved the poor solubility of CsA. The ciliostatic and haemolytic activities of maltosyl-alpha-CD were the weakest of all the tested CDs. CsA inhaled alone showed inhibitory effects on allergen-induced eosinophilia. Inhalation of the complex of CsA with maltosyl-alpha-CD, where the dose of CsA was approximately nine-times less than that of CsA inhaled alone, also inhibited eosinophil accumulation significantly, with a longer duration of action in comparison with the response to CsA alone. Thus the effective dose of cyclosporin A could be reduced by formation of a complex with maltosyl-alpha-cyclodextrin, and a wider therapeutic safety margin by inhalation of cyclosporin A as a complex with maltosyl-alpha-cyclodextrin could be expected.

Analysis of a uranium solution for evaluating the total number of fissions in the JCO criticality accident in Tokai-mura

The uranium solution in the precipitation tank in the JCO's uranium conversion facility was analyzed in order to evaluate the total number of fissions in the criticality accident. Two analytical groups at JAERI performed chemical analyses independently in order to check the validity of the results: the concentration of the fission products (95Zr, 99Mo, 103Ru, 131I, 140Ba, etc), uranium, boron and impurity elements in the solution. The analytical results obtained by the two groups were almost in agreement within the analytical error. The number of fissions per one gram of uranium in the accident was determined to be (1.5 +/- 0.1 ) x 10(14). Also, the total number of events was evaluated to be (2.5 +/- 0.1) x 10(18) fissions using the total amount of uranium (16.6 kg) fed into the precipitation tank at the accident.

Temporal bone findings in multiple endocrine neoplasia type 2B

To our knowledge, present case is the first published report of temporal bone findings in multiple endocrine neoplasia type 2B (MEN-2B). We describe a 43-year-old Japanese man with medullary thyroid carcinoma (MTC), pheochromocytoma, mucosal neuroma and a Marfanoid body habitus. The collateral adrenal tumors and MTC were removed surgically. However, 14 years after surgery, the MTC and pheochromocytoma recurred and the patient died of intracranial hemorrhage due to hypertension. During the autopsy, metastatic MTC was detected in the liver, lungs, kidneys, pancreas and cervical lymph nodes. Recurrent pheochromocytoma was present in the right kidney. Mucosal neuromas were found in the tongue, gastrointestinal tract and vesical nerve plexus. The following histopathological findings were seen in both temporal bones: metastatic MTC was found as well as neuromas and the cochlear aqueduct was widely patent.

[Experimental studies of the protective effect of ginkgo biloba extract (GBE) on cisplatin-induced toxicity in rats]

Cisplatin (CDDP) is an effective antineoplastic agent in the treatment of solid malignant tumors. Its clinical use, however, is limited because of various side effects including sensorineural hearing loss. Several agents have been proposed to reduce these side effects. GBE has recently been reported to scavenge superoxide and hydroxyl radicals, resulting in a reduction of lipid peroxidation. GBE is expected to protect against CDDP-induced toxicity because its generative mechanism is thought to be associated with free-radical formation. The purpose of the present study was to evaluate GBE's efficacy as a protective agent against cisplatin-induced ototoxicity. Fisher rats were used in this study and were divided into three treatment groups: 1) animals administered 1.0 mg of CDDP per kg for 10 days (Group I), 2) animals receiving 100 mg of GBE per kg 90 min before administration 1.0 mg of CDDP per kg (Group II) and 3) a vehicle control (Group III). First, the protective effect of GBE on CDDP-induced ototoxicity was investigated. The auditory threshold was evaluated by means of the compound action potential (CAP) recording. After CAP recordings, cochlear sensory epithelia were observed throughout the cochlea by scanning electron microscopy. In Group II, the elevation of CAP thresholds at 12 kHz, 16 kHz, 20 kHz and the missing rate for the outer hair cells were significantly reduced as compared to those in Group I. These data suggest that GBE is effective for otoprotection against CDDP. Second, the protective effect of GBE on CDDP-induced nephrotoxicity was evaluated. Nephrotoxicity was evaluated by means of measurement of serum BUN and creatinine and histopathological examination of the kidney. These were significant differences in serum BUN and creatinine levels between Group I and Group II. Third, the influence of GBE against the antitumor effect of CDDP was researched in the rats inoculated subcutaneously with SCC-158 squamous cell carcinoma cells. There was no difference in tumor growth rate (TGR) between Group I and Group II. The result suggested that the combined administration had no influence on the antitumor activity of CDDP. In conclusion, the co-administration of CDDP with GBE is beneficial to ameliorate CDDP-induced toxicity without attenuation of CDDP antitumor activity.

Effects of chroman derivatives on platelet aggregation induced by some aggregating agents in rabbits

1. We synthesized 10 chroman derivatives (CD-1 to CD-10) derived from khellactone, including praeruptorin A and praeruptorin B and examined the effects of these compounds on rabbit platelet aggregation. 2. These compounds exhibited an inhibitory effect on platelet-activating factor (PAF)-induced platelet aggregation and their effects were more potent on PAF-induced platelet aggregation than on adenosine triphosphate (ADP)-, arachidonate (AA)- or collagen-induced platelet aggregation. In particular, (+/-)-cis-5-methoxy-6-methoxycarbonyl-2,2-dimethyl-3,4-ditiglyloxychr oman (CD-6), (+/-)-cis-5-methoxy-6-(2-methoxycarbonylethenyl)-2,2-dimethyl- 3,4-ditiglyloxychroman (CD-8), (+/-)-cis-3,4-diacetoxy-5-methoxy-2,2-dimethyl-6-propylchroman (CD-9) and (+/-)-cis-5-methoxy-2,2-dimethyl-6-propyl-3,4-ditiglyloxychroman (CD-10) showed a moderate inhibition of PAF-induced platelet aggregation. 3. From these findings, it is suggested that compounds with potent PAF antagonist activities have the following features: (i) a tiglyloxy moiety is required at the 3 and 4 positions; and (ii) the methoxy moiety is also required at the 5 position of chroman skeleton in khellactone.

SDZ ENA 713 facilitates central cholinergic function and ameliorates spatial memory impairment in rats

We have clarified the effects of SDZ ENA 713 (ENA), a new phenyl-carbamate derivative, on the spatial learning impairment and neurochemical indices of central cholinergic neurons in rats. Basal forebrain (BF) lesioning with ibotenic acid markedly impaired acquisition ability in the water maze task without changing swimming rates and decreased choline acetyltransferase (ChAT) activity in the frontal cortex of rats. ENA (0.1, 0.2 mg/kg, p.o.) significantly ameliorated the impairment in acquisition ability in a dose-dependent manner. At 0.2 mg/kg, ENA prevented the reduction in ChAT activity. In normal rats, ENA (1 mg/kg, p.o.) increased extracellular ACh concentration of the prefrontal cortex. On the other hand, tissue concentrations of norepinephrine, serotonin, dopamine and their metabolites were not changed in the frontal cortex, hippocampus and striatum of normal rats. These results suggest that ENA ameliorates spatial learning disability by not only facilitating the cholinergic transmission, but normalizing impaired ChAT activity in the learning-impaired rat model.

Ameliorating effects of SDZ ENA 713 on age-associated decreases in learning performance and brain choline acetyltransferase activity in rats

In the present study, we have investigated the effects of SDZ ENA 713 on spatial learning deficits in aged rats. Using the same animals, the effect of SDZ ENA 713 on choline acetyltransferase was simultaneously studied to obtain a basis for the behavioral study. In the aged rats, the spatial learning and choline acetyltransferase activity in the frontal cortex were significantly deteriorated compared with young adult rats. SDZ ENA 713 (0.2 mg/kg) significantly shortened the time to reach a hidden platform without affecting swim rates in the water maze task. SDZ ENA 713 (0.1 and 0.2 mg/kg) inhibited aging-induced decreases in choline acetyltransferase activity in the frontal cortex. These results suggest that SDZ ENA 713 ameliorates aging-induced learning deficits and cholinergic dysfunction in rats.

Photochemistry of acetylenic ketones in micellar solutions as studied by product-yield-detected ESR and transient absorption techniques

The electron spin resonance (ESR) spectra of the transient radical pairs in the photoreduction of 1,5-diphenyl-1,4-pentadiyn-3-one(I) and 1,3-diphenyl-2-propyn-1-one(II) in sodium dodecyl sulfate (SDS) micellar solutions have been obtained by using the product-yield-detected ESR (PYESR) technique. The PYESR spectra, detected by tracing the microwave effect on the spin-adduct yield as functions of the magnetic field, show the ESR spectra of the ketyl radical of the ketone and SDS radical as the components of the radical pairs. In addition, the growth and the decay processes of the radical pair were observed through detecting the effect of microwave pulse as functions of the delay period between a laser pulse and the off and on time, respectively, of a microwave pulse. The absorption spectra of transient species have also been obtained by using the laser flash photolysis technique. Through the analysis of these data and molecular orbital calculations, the role of acetylenic groups in the photoreactivity of acetylenic ketones is discussed.

[Intravenous DSA as a screening method for cerebral aneurysms]

Intravenous DSA (IVDSA) was evaluated as a screening method for cerebral aneurysms. It was performed 390 times in 372 cases. Clinically useful images were obtained in 94.1% in all examinations. Nineteen aneurysms were visualized in cerebral angiography among 21 cases with SAH or 3rd nerve palsy, whereas in IVDSA 15 aneurysms were noted. Aneurysms not visualized in IVDSA were all 4 mm or less in size. Therefore, aneurysms, more than 4 mm in size, which have higher risks for rupture, were detectable in IVDSA. Based on these findings, IVDSA is considered to be clinically useful in screening for aneurysms. In all 372 cases, 33 aneurysms were suspected in IVDSA findings, whereas in cerebral angiography 21 of them turned to be aneurysms. Such 12 false positive cases were distributed mainly at anterior communicating and middle cerebral arteries. Improvement of image resolution, avoidance of vessel overlapping and proper selection of screened cases should be investigated for further development of this screening method.

Biphenyls, a new class of compound that inhibits platelet-activating factors

Honokiol (1), a constituent of Magnoliae cortex, and related synthetic biphenyls inhibited the platelet aggregation induced by a few aggregating agents. In particular, compounds 3, 5, and 10 had an inhibitory effect on platelet activating factor (PAF), which provides a new class of PAF inhibitor.

Effect of blood purification on the kidney function of the jaundiced rat

This paper is aimed at evaluating the effect of blood purification on the mitochondrial functions of the kidney in jaundiced rats. At 1, 2, or 3 weeks after bile duct ligation and dissection, obstructive jaundiced rats were utilized for experiment. Cross circulation in 1 ml/min between jaundiced rats and normal rats was performed for 1 or 3 h. Immediately and 24 h after cross circulation, the rats were killed and mitochondrial respiratory functions of the kidney were assessed by measuring oxygen consumption. Mitochondrial function, especially ATP synthesis, showed significant improvement in jaundiced rat with 2 or 3 weeks of biliary obstruction. Cross circulation for 3 h was more effective than that for 1 h. These data suggest that the renal energy production can be increased significantly in obstructive jaundice by blood purification treatment.

Development of tolerance and supersensitivity to phencyclidine in rats after repeated administration of phencyclidine

In rats treated with phencyclidine (PCP) repeatedly (PCP 10 mg/kg per day for 14 days), the back-pedalling, head-weaving and turning induced by PCP were attenuated (tolerance), while PCP-induced sniffing, rearing and ambulation were potentiated (supersensitivity). The behavior induced by the direct and indirect serotonin (5-HT) agonists, 5-methoxy-N,N-dimethyltryptamine and p-chloroamphetamine, was attenuated, while the sniffing, rearing or licking induced by the direct and indirect dopamine (DA) agonists, apomorphine and methamphetamine, were potentiated in the chronic PCP-treated rats. The DA and 5-HT contents in the nucleus accumbens and the ratio of HVA to DA in the striatum increased following the repeated PCP administration. Pentobarbital-induced sleep time did not change in the chronic PCP-treated rats as compared with the control rats. In addition, there was no significant difference between the disappearance rate of PCP in the brain of the rats treated with PCP repeatedly and the rate in the control rats. These results suggest that functional changes in the dopaminergic and serotonergic neuronal systems develop on repeated administration of PCP but that such changes do not develop in the hepatic drug-metabolizing system. In addition, tolerance develops in the serotonergic neuronal system while supersensitivity develops in the dopaminergic neuronal system. Biochemical findings suggest that increased mesolimbic dopaminergic neuronal function plays an important role in the development of the supersensitivity.

Potentiation of phencyclidine-induced stereotyped behaviors in rats by thiorphan and bestatin

We investigated the effects of thiorphan, a specific inhibitor of enkephalinase A and bestatin, a specific inhibitor of aminopeptidase, on the stereotyped behaviors induced by phencyclidine (PCP) in cannulated rats. The PCP-induced turning was significantly potentiated when thiorphan (50 micrograms) and bestatin (50 micrograms) were injected simultaneously into the rat lateral ventricle. The increase of PCP-induced turning was completely antagonized by the pretreatment with naloxone. Thiorphan (50 micrograms) or bestatin (50 micrograms) alone failed to potentiate PCP-induced turning. Thiorphan and/or bestatin did not affect significantly the PCP-induced head weaving and back-pedalling except that thiorphan (50 micrograms) potentiated the PCP-induced head weaving 15-18 min after the PCP injection. The combination of thiorphan and bestatin alone did not induce any behavioral change. These results suggest that thiorphan and bestatin produce an increase of endogenous enkephalins and that as a result, PCP-induced turning may be enhanced.

[Significance of cross-circulation on obstructive jaundice in rats with special reference to the mitochondrial function of the liver and kidney]

Cross-circulation was performed to investigate the mitochondrial respiratory function of the liver and kidney in rats after 1, 2 and 3 weeks of biliary obstruction. Serum bilirubin and total bile acids concentration in blood in rats with biliary obstruction markedly decreased with 3 hours cross-circulation. There demonstrated, however, no significant change in mitochondrial function in the liver after cross-circulation. In contrast, mitochondrial function in the kidney showed significant improvement after 3 hours cross-circulation. Mitochondrial respiratory function in normal partner rats cross-circulation with jaundiced rats demonstrated temporal deterioration in the kidney and prolonged deterioration in the liver. It can be concluded that cross-circulation or plasma exchange might be useful for the prevention of renal failure in obstructive jaundice, since cross-circulation induced persistent improvement of the mitochondrial respiratory function in the kidney deteriorated by biliary obstruction.

Human ACTH, beta-lipotropin and beta-endorphin levels in maternal plasma at delivery

Adrenocorticotropic hormone (ACTH), beta-lipotropin (beta-LPH) and beta-endorphin (beta-EP) were measured simultaneously in maternal plasma at delivery. Mean concentrations of beta-LPH and beta-EP in maternal plasma at delivery were significantly higher than those in normal control. There were significant positive correlations among ACTH, beta-LPH and beta-EP concentrations, respectively. These data suggest that beta-LPH and beta-EP were elevated during delivery and in parallel with each other.

Experimental and clinical studies on renal disturbance in obstructive jaundice

Renal functions and the clinical courses of 14 patients with renal disturbances associated with obstructive jaundice were studied. All patients had high concentrations of serum bilirubin, long durations of jaundice and episodes of shock due to massive hemorrhage or severe inflammation. In an experimental study on jaundiced rats, effects of hypotension or bilateral renal artery occlusion on renal function and renal cortical mitochondrial respiration at 1 week, 3 or 6-weeks after biliary obstruction were investigated. In jaundiced rats, there was no remarkable difference in renal function, but the renal mitochondrial respiration indices decreased with prolongation of the biliary obstruction. In hypotensive rats with prolonged biliary obstruction, the mitochondrial function was impaired, and in the rats with renal artery occlusion, the mitochondrial impairment was more severe. Based on these clinical and experimental data, it is tentatively suggested that patients with prolonged jaundice should be considered in a prodromal state of renal failure and that any minute circulatory failure may induce acute renal failure.

Simple uniaxial and uniform biaxial deformation of nearly isotropic incompressible tissues

A method is developed for analyzing in a unified manner both uniaxial and uniform biaxial strain data obtained from nearly isotropic tissues. The formulation is a direct application of nonlinear elasticity theory pertaining to large deformations. The general relation between Eulerian stress (sigma) and extension ratio (lambda) in soft isotropic elastic bodies undergoing uniform deformation takes the simple form: sigma = ((lambda(3) - 1)/lambda) f(lambda), where f(lambda) must be determined for each material. The extension ratio may be either greater than 1.0 (uniaxial elongation), or lie between zero and 1.0 (uniform biaxial extension). Simple analytical functions for f(lambda) are most readily found for each tissue by plotting all data as (lambda(3) - 1)/lambdasigma vs. lambda. Of those tissues investigated in this way (dog pericardium and pleura, and cat mesentery and dura), all but pleura could be adequately described by a parabola: 1/f(lambda) = 1/k{[(lambda(M) - lambda)(lambda - lambda(m))]/[lambda(M) - lambda(m)}. In these instances, three material constants per tissue (K, lambda(M), lambda(m)) served to predict approximately the stresses attained during both small and large deformations, in strips and sheets alike. It was further found that the uniaxial strain asymptote (lambda(M)) was linearly related to the biaxial strain asymptote (Lambda(M)), thus effectively reducing the number of constants by one.