Sufficient prophylactic efficacy with minor adverse effects by intravesical instillation of low-dose bacillus Calmette-Guérin for superficial bladder cancer recurrence

BACKGROUND: Intravesical instillation of bacillus Calmette-Guérin (BCG) is the most efficient strategy for prophylaxis of superficial bladder cancer recurrence. Adverse effects of BCG are major obstacles, but the reduction of BCG dose could minimize these effects. The efficacy and adverse effects of half-dose (40 mg) BCG, Tokyo 172 strain, were prospectively evaluated. METHODS: A total of 93 patients with superficial bladder cancer (pTa or pT1) were sequentially assigned to receive either 40 or 80 mg of BCG after transurethral resection. BCG was administered weekly for 6 weeks postoperatively. Eighty patients observed longer than 12 months after BCG therapy (41, 40 mg group; 39, 80 mg group) were analyzed. RESULTS: BCG therapy course was completed in 71 patients. Tumor recurrence was recognized in 11 of 40 patients in the 40 mg group and in 5 of 31 patients in the 80 mg group. There was no significant difference in tumor recurrence rate between the two groups (P = 0.547). BCG therapy was withdrawn in 1 patient in the 40 mg group and in 8 patients in the 80 mg-group because of BCG-related adverse effects. The morbidity of BCG-related toxicity was significantly higher in the 80 mg group. CONCLUSION: Half-dose of BCG Tokyo 172 strain had a similar efficacy and its toxicity was significantly lower compared to the standard dose. Thus, half-dose of this strain might be suitable, at least for initial BCG therapy, for the prophylaxis of bladder cancer recurrence. Further study would be necessary to clarify the efficacy of low-dose instillation in high-risk patients.     

Frequency Dependent Shortening of Conduction Time through the Reentrant Pathway during Transient Entrainment of Ventricular Tachycardia

In a patient with nonischemic ventricular tachycardia (VT), VT was entrained and the conduction time from the pacing site to the entrained local electrogram showed a rate dependent shortening and its degree affected by the pacing site. The QRS complex, which was entrained by the last pacing stimulus, was constant and identical to that of VT and no rate dependent facilitated conduction was observed when the heart was paced at similar paced cycle lengths during sinus rhythm. As the mechanism of the shortening of the conduction time through the reentrant circuit, a shift of the entrance seems most likely.     

Intraoperative transesophageal echocardiography for inferior vena caval tumor thrombus in renal cell carcinoma

BACKGROUND: We investigated the advantages of intraoperative transesophageal echocardiography (TEE) during inferior vena caval tumor thrombectomy in renal cell carcinoma (RCC). METHODS: Five patients with RCC that extended into the inferior vena cava (IVC) underwent radical nephrectomy. To remove the tumor thrombus in the IVC, an inflated Fogarty balloon catheter was used to pull the thrombus below the level of the hepatic veins with real-time TEE monitoring. RESULTS: In all cases, TEE monitoring during surgery provided an accurate and excellent view of the IVC thrombus. TEE was particularly helpful for the thrombectomy to minimize hepatic mobilization by using occlusion balloon catheter in two patients whose thrombus extended to the intrahepatic IVC. CONCLUSIONS: Intraoperative real-time TEE monitoring is a safe, minimally invasive technique that can provide accurate information regarding the presence and extent of IVC involvement, guidance for placement of a vena caval clamp, confirmation of complete removal of the IVC thrombus and intervention using catheters to assist in thrombectomy.     

Deficiency of Testosterone Associates with the Substrate of Atrial Fibrillation in the Rat Model

Background: Since the prevalence of atrial fibrillation (AF) increases progressively with aging, especially in men, we hypothesized that testosterone might affect the occurrence of AF.
Methods and Results: We examined the electrophysiological properties of the atria in isolated-perfused hearts of sham-operated male (SM), female (SF), orchiectomized male with and without administration of testosterone (ORCH-T and ORCH), and ovariectomized female (OVX) Sprague-Dawley rats. An electrophysiological study revealed that repetitive atrial responses induced by electrical stimuli significantly increased in ORCH rats without changes in other electrophysiological properties and were abolished by administration of testosterone. To investigate the underlying mechanisms, we evaluated the expression level of calcium-handling proteins. In ORCH rats, the immunoreactive protein level of ryanodine receptor type 2 (RyR2) and sodium–calcium exchanger significantly increased as compared with SM and ORCH-T rats without alterations in the level of FK506-binding protein (FKBP12.6), sarcoendoplasmic reticulum Ca-ATPase, and phospholamban. Immunoprecipitation analysis demonstrated decreased binding of FKBP12.6 to RyR2 in ORCH rats, which was prevented by testosterone. In contrast, the expression levels of these proteins showed no significant differences between SF and OVX rats.
Conclusion: Deficiency of testosterone was arrhythmogenic in rat atria possibly through less binding of FKBP12.6 to RyR2, which could induce feasible calcium leakage from the sarcoendoplasmic reticulum. These results would explain, at least in part, the increase in the prevalence of AF in accordance with the decline of testosterone particularly in elderly men.     

Experimental Study About Removal of the Implanted Tined Polyurethane Ventricular Lead by Radiofrequency Waves Through the Lead

Polyurethane pacemaker leads are widely used nowadays. However, only a few studies have been done to investigate the fixation mechanism of polyurethane leads. To elucidate how pacemaker leads are fixed at the early phase after implantation, polyurethane-insulated tined ventricular leads were implanted in seven mongrel dogs. One to 4 months later, tips of the leads were anchored among the trabeculae and the distal part of the leads were encapsulated by whitish fibrous tissue. It was found that not organized thrombi, but cell reaction with various stages of inflammatory cells was responsible for forming the fibrous tissue. We attempted to remove the lead by delivering radiofrequency wave through the lead. However, no lead could be removed.     

Effects of Chronotropic Responsive Cardiac Pacing on Ventilatory Response to Exercise in Patients with Complete AV Block

To identify the effect of chronotropic responsive cardiac pacing on the ventilatory response to exercise, ten selected patients with complete atrioventricular block underwent paired cardiopulmonary exercise tests in fixed rate ventricular (WI) and dual chamber (DDD) or rate responsive ventricular (VVIR) pacing modes. Compared to VVI pacing, DDD or VVIR pacing increased peak oxygen uptake (P < 0.005) and augmented anaerobic threshold (P < 0.001), In eight patients, dyspnea was the major symptom limiting exercise with VAT pacing and this was markedly attenuated with DDD or VVIR pacing. In all patients, ventilation (VE) and the ratio of ventilation to CO₂ production (VE/VCO₂) were consistently higher with VVI pacing during exercise. To compare the response of the two pacing modes at the same workloads in an aerobic condition, we measured ventilatory variables 1 minute prior to the anaerobic threshold obtained with VVI pacing. When DDD or VVIR pacing was compared with VVI pacing, VE and VE/VCO₂ significantly decreased from 20.5 ± 5.3 L/min to 18.3 ± 5.0 L/min (P < 0.005) and from 35.9 ± 5.8 to 31.9 ± 5.0 (P < 0.003), respectively. Respiratory frequency rose significantly more with VVI pacing (P < 0.001) despite an unchanged tidal vohame. Although peak VE did not differ between the two pacing modes, VE/VCO₂ at the peak exercise increased significantly more with VVI pacing (P < 0.005). Respiratory frequency also rose more with VVI pacing (P < 0.005) and tidal volume did not change. This study suggests that chronotropic responsive cardiac pacing attenuates the exertional dyspnea by improving the ventilatory response to exercise as well as increasing the cardiac output in patients with complete atrioventricular block.     

Impact of COVID-19 on the Volume of Acute Stroke Admissions: A Nationwide Survey in Japan

This study aimed to measure the impact of the COVID-19 pandemic on the volumes of annual stroke admissions compared with those before the pandemic in Japan. We conducted an observational, retrospective nationwide survey across 542 primary stroke centers in Japan. The annual admission volumes for acute stroke within 7 days from onset between 2019 as the pre-pandemic period and 2020 as the pandemic period were compared as a whole and separately by months during which the epidemic was serious and prefectures of high numbers of infected persons. The number of stroke patients declined from 182,660 in 2019 to 178,083 in 2020, with a reduction rate of 2.51% (95% confidence interval [CI], 2.58%-2.44%). The reduction rates were 1.92% (95% CI, 1.85%-2.00%; 127,979-125,522) for ischemic stroke, 3.88% (95% CI, 3.70%-4.07%, 41,906-40,278) for intracerebral hemorrhage, and 4.58% (95% CI, 4.23%-4.95%; 13,020-12,424) for subarachnoid hemorrhage. The admission volume declined by 5.60% (95% CI, 5.46%-5.74%) during the 7 months of 2020 when the epidemic was serious, whereas it increased in the remaining 5 months (2.01%; 95% CI, 1.91%-2.11%). The annual decline in the admission volume was predominant in the five prefectures with the largest numbers of infected people per million population (4.72%; 95% CI, 4.53%-4.92%). In conclusion, the acute stroke admission volume declined by 2.51% in 2020 relative to 2019 in Japan, especially during the months of high infection, and in highly infected prefectures. Overwhelmed healthcare systems and infection control practices may have been associated with the decline in the stroke admission volume during the COVID-19 pandemic.