Ionic currents in single smooth muscle cells of the human vas deferens

PURPOSE: Smooth muscle cells of the vas deferens have an important role in carrying sperms to the exterior but little is known of their electrophysiological properties. We characterized the voltage-gated ion channel currents in single smooth muscle cells of the human vas deferens (HVSMCs). MATERIALS AND METHODS: We observed contractile responses of 8 circular smooth muscle strips of the human vas deferens to a high concentration (10 mM) of tetraethylammonium. HVSMCs were isolated using proteolytic enzymes (collagenase and papain), and were used for an electro-physiological study using whole cell and inside-out patch clamp configurations. RESULTS: The application of 10 mM tetraethylammonium induced rhythmic contractions of the strips. When HVSMCs were dialyzed with a KCl solution, step depolarizations of membrane potential evoked oscillatory outward K currents that were not inactivated. The large conductance Ca activated K (BKCa) and delayed rectifier components of the outward current were identified. The BKCa channel showed a large single channel conductance (162.7 +/- 13.2 pS with 5 mM K in the patch pipette). Two types of Ca currents were identified in the whole cell configuration. With a cell held at -50 mV an L-type Ca current was present during a depolarizing step pulse. From a holding potential of -90mV L-type and T-type Ca currents were elicited by depolarizing step pulses. CONCLUSIONS: HVSMCs have 2 (L and T) types of Ca channels and 2 types of K (BKCa and delayed rectifier) channels. Voltage dependent changes of these ion channels and their interactions may be important in regulating vas contractility.     

Hemodynamic changes during posterior vessel off-pump coronary artery bypass: comparison between deep pericardial sutures and vacuum-assisted apical suction device

Background

Displacement of the heart to expose posterior vessels during off-pump coronary artery bypass may cause hemodynamic derangement. The aims of this study were (1) to elucidate the hemodynamic changes during off-pump coronary artery bypass for the obtuse marginal branch (OM) of the left circumflex artery; and (2) to compare the hemodynamic changes caused by a deep pericardial suture technique with those caused by a vacuum-assisted apical suction device for displacement of the heart.

Methods

Hemodynamic changes during posterior vessel off-pump coronary artery bypass were studied in a prospective randomized manner. A deep pericardial suture technique (group 1, n = 10) or a vacuum-assisted apical suction device (group 2, n = 10) was used to facilitate the exposure of the OM. Hemodynamic variables such as cardiac index, stroke volume index (SVI), mean arterial pressure, mean pulmonary artery pressure, central venous pressure, pulmonary capillary wedge pressure, heart rate, systemic vascular resistance, pulmonary vascular resistance, left ventricular stroke work index, and right ventricular stroke work index were monitored during off-pump coronary artery bypass. Hemodynamic data were obtained before revascularization of the left anterior descending coronary artery at a baseline (T0), 3 minutes after heart displacement for revascularization of OM (T1), 3 minutes after the beginning of OM grafting (T2), and 3 minutes after the completion of OM grafting and heart repositioning (T3).

Results

There were no significant differences in the baseline hemodynamic variables (T0) between the two groups. In group 1, SVI, cardiac index, left ventricular stroke work index, and right ventricular stroke work index decreased significantly, and central venous pressure and pulmonary capillary wedge pressure increased significantly, during displacement of the heart (T1, p < 0.05). In group 2, SVI decreased significantly, and central venous pressure, pulmonary capillary wedge pressure, and mean pulmonary artery pressure increased significantly during displacement of the heart (T1, p < 0.05). The percent changes of cardiac index, SVI, and right ventricular stroke work index during OM grafting (T2) in comparison with baseline values (T0) were significantly larger in group 1 than in group 2 (cardiac index, 73% ± 12% versus 90% ± 11%; SVI, 69% ± 12% versus 86% ± 8%; right ventricular stroke work index, 30% ± 17% versus 71% ± 25%, in groups 1 versus 2, respectively; p < 0.05).

Conclusions

Displacement of the heart using either a deep pericardial suture technique or a vacuum-assisted apical suction device caused a significant decrease in SVI. The hemodynamic changes during OM grafting were smaller when using a vacuum-assisted apical suction device.     

The effects of subluxation of the femoral head with avascular necrosis in growing rabbits

To validate the adverse effects of subluxation of the femoral head in Legg-Calve-Perthes disease, the authors made an experimental model of Perthes disease with subluxation in growing rabbits by interrupting the epiphyseal artery (devascularization) and immobilizing the knee in extension (immobilization). Seventy-two rabbits, 4 to 5 weeks old, were divided into three groups: group A with both devascularization and immobilization (25 rabbits), group B with devascularization only (25 rabbits), and group C with immobilization only (22 rabbits). In each experimental group, four to six rabbits each were killed at 1, 2, 4, 8, and 12 weeks. After reviewing the serial radiographs and gross specimens, the authors found six radiologic and six macroscopic abnormalities. The incidence and the severity of deformity in group A rabbits were higher than that of groups B or C in terms of the overall incidence of deformities (P <0.001), head deformity scores (P <0.001), and the incidence of a total collapse of the capital femoral epiphysis. In conclusion, subluxation of the immature femoral head with avascular necrosis in rabbits increased femoral head deformities.     

Does Functional Mitral Regurgitation Improve with Isolated Aortic Valve Replacement?

BACKGROUND: The surgical treatment of mitral valve regurgitation (MR) at the time of aortic valve replacement (AVR) remains controversial. The purpose of this study was to evaluate the change in severity of MR following isolated AVR, and to determine survival benefit. METHODS: Between 1991 and 2001, 250 patients underwent isolated AVR; 196 patients had concomitant functional MR. Follow-up transthoracic echocardiography (TTE) was available on 107 patients, with a median of 818 +/- 752 days. Aortic valve was stenotic in 77 and regurgitant in 30 patients. RESULTS: Mean age was 67 +/- 15 years and 57 (53%) were male. Preoperative MR was trivial (1+) in 27 (25%), mild (2+) in 44 (41%), moderate (3+) in 29 (27%), and severe (4+) in 7 (7%). At follow-up TTE, MR improved by 1 or 2 grades in 48 patients (45%). Of patients with preoperative 2+ MR, 19 (43%) improved, 16 (36%) remained unchanged, and 9 (21%) worsened. Although some patients with preoperative 3+ MR exhibited improvement, 11 (38%) remained with moderate-to-severe MR. Of those with a preoperative MR of 4+, 3 (71%) improved, and 4 remained with 3-4+ MR. For patients with preoperative 1 to 2+ MR, survival at 3 years was 98% compared to 78% for those with 3 to 4+ MR (p = 0.038). CONCLUSION: Functional MR does not always improve after isolated AVR. Survival is lower for patients with preoperative 3 to 4+ MR. Moderate-to-severe MR should be repaired at the time of aortic valve surgery.     

Intramuscular nerve distribution pattern of ankle invertor muscles in human cadaver using sihler stain

Introduction: We sought to the ideal sites for botulinum toxin injection by examining the intramuscular nerve patterns of the ankle invertors. Methods: A modified Sihler method was performed on the flexor hallucis longus, tibialis posterior, and flexor digitorum longus muscles (10 specimens each). The muscle origins, nerve entry points, and intramuscular arborization areas were measured as a percentage of the total distance from the most prominent point of the lateral malleolus (0%) to the fibular head (100%). Results: Intramuscular arborization patterns were observed at 20–50% for the flexor hallucis longus, 70–80% for the tibialis posterior, and 30–40% for the flexor digitorum longus. Conclusions: These findings suggest that treatment of muscle spasticity of the ankle invertors involves botulinum toxin injections in specific areas. These areas, corresponding to the areas of maximum arborization, are recommended as the most effective and safest points for injection. Muscle Nerve 53 : 742–747, 2016     

Pitfalls and Important Issues in Testing Reliability Using Intraclass Correlation Coefficients in Orthopaedic Research

Background

Intra-class correlation coefficients (ICCs) provide a statistical means of testing the reliability. However, their interpretation is not well documented in the orthopedic field. The purpose of this study was to investigate the use of ICCs in the orthopedic literature and to demonstrate pitfalls regarding their use.

Methods

First, orthopedic articles that used ICCs were retrieved from the Pubmed database, and journal demography, ICC models and concurrent statistics used were evaluated. Second, reliability test was performed on three common physical examinations in cerebral palsy, namely, the Thomas test, the Staheli test, and popliteal angle measurement. Thirty patients were assessed by three orthopedic surgeons to explore the statistical methods testing reliability. Third, the factors affecting the ICC values were examined by simulating the data sets based on the physical examination data where the ranges, slopes, and interobserver variability were modified.

Results

Of the 92 orthopedic articles identified, 58 articles (63%) did not clarify the ICC model used, and only 5 articles (5%) described all models, types, and measures. In reliability testing, although the popliteal angle showed a larger mean absolute difference than the Thomas test and the Staheli test, the ICC of popliteal angle was higher, which was believed to be contrary to the context of measurement. In addition, the ICC values were affected by the model, type, and measures used. In simulated data sets, the ICC showed higher values when the range of data sets were larger, the slopes of the data sets were parallel, and the interobserver variability was smaller.

Conclusions

Care should be taken when interpreting the absolute ICC values, i.e., a higher ICC does not necessarily mean less variability because the ICC values can also be affected by various factors. The authors recommend that researchers clarify ICC models used and ICC values are interpreted in the context of measurement.     

Prediction of Recurrence after Curative Resection of Hepatocellular Carcinoma using Liver Stiffness Measurement (FibroScan?)

Background

The purpose of this study was to investigate whether preoperative liver stiffness measurement (LSM) can predict recurrence after curative resection of hepatocellular carcinoma (HCC). LSM using FibroScan^? can assess the severity of liver fibrosis, which is significantly associated with recurrence after curative resection of HCC.

Methods

Between February 2006 and March 2009, 133 patients who underwent preoperative LSM and curative resection for HCC were enrolled in this prospective study. LSM values were analyzed for association with recurrence, together with other clinical variables.

Results

The mean age of the patients (117 men and 16 women) was 57?years. During the follow-up period (median, 25.0 (range, 3.0?C54.6) months), HCC recurred in 62 (46.6?%) patients. In multivariate analysis, together with satellite nodule and Edmonson-Steiner grade III?CIV, LSM was selected as an independent predictor of recurrence (P?<?0.05; hazard ratio, 1.034; 95?% confidence interval, 1.007?C1.061). When the study population was stratified into two groups using the optimal cutoff value (13.4?kPa) that maximized the sum of sensitivity (64.7?%) and specificity (76.1?%) from time-dependent receiver operating characteristic curves (area under the receiver operating characteristic curve?=?0.676), patients with LSM values >13.4?kPa were at a significantly greater risk for recurrence with a hazard ratio of 1.925 (P?=?0.01; 95?% confidence interval, 1.17?C3.168) compared with those with LSM values ??13.4?kPa.

Conclusions

Our data suggest that LSM can be a useful predictor of recurrence after curative resection of HCC.     

The optimal dose of esmolol and nicardipine for maintaining cardiovascular stability during rapid-sequence induction

Study ObjectiveTo determine the optimal dose of esmolol in combination with nicardipine in effectively blocking undesirable cardiovascular responses during rapid-sequence induction.DesignProspective, randomized clinical comparison study.SettingOperating room of a university hospital.Patients200 ASA physical status 1 and 2 patients requiring general anesthesia with endotracheal tube placement.InterventionsPatients were randomly allocated into one of 4 groups: Group E0 (no esmolol; control), Group E0.25 (esmolol 0.25 mg/kg), Group E0.5 (esmolol 0.5 mg/kg), and Group E1.0 (esmolol 1.0 mg/kg). All patients received 20 μg/kg of nicardipine, and esmolol was then given according to group allocation. Ninety seconds later, thiopental sodium 5 mg/kg and succinylcholine 1.0 mg/kg were injected. Endotracheal intubation was performed 60 seconds after injection of the anesthetic agents.MeasurementsSystolic (SBP), diastolic (DBP), and mean arterial (MAP) pressures; heart rate (HR), and rate-pressure product (RPP) were measured 30 seconds before and after intubation, and at 1, 3, 5, and 10 minutes after intubation. Rate changes using baseline values as the standard [rate changes = measured value/baseline value × 100 (%)] were calculated.Main ResultsSignificant attenuations in SBP, MAP, HR, and RPP after intubation were noted in the experimental groups as compared with the control group (P < 0.05). Rate changes in HR in Groups E0.5 and E1.0 were significantly lower than those in Group E0.25 immediately and one minute after intubation (P < 0.05). No difference in rate changes in HR were noted between the E0.5 and E1.0 groups.ConclusionsThe combination of nicardipine 20 μg/kg and esmolol 0.5 mg/kg most effectively attenuates the cardiovascular responses during rapid-sequence induction.