Left Ventricular Lead Placement Targeted at the Latest Activated Site Guided by Electrophysiological Mapping in Coronary Sinus Branches Improves Response to Cardiac Resynchronization Therapy.

INTRODUCTION: Electrophysiological mapping (EPM) in coronary sinus (CS) branches is feasible for guiding LV lead placement to the optimal, latest activated site at cardiac resynchronization therapy (CRT) procedures. However, whether this procedure optimizes the response to CRT has not been demonstrated. This study was to evaluate effects of targeting LV lead at the latest activated site guided by EPM during CRT. METHODS: Seventy-six consecutive patients with advanced heart failure who were referred for CRT were divided into mapping (MG) and control groups (CG). In MG, the LV lead, also used as a mapping bipolar electrode, was placed at the latest activated site determined by EPM in CS branches. In CG, conventional CRT procedure was performed. Patients were followed for 6 months after CRT. RESULTS: Baseline characteristics were comparable between the 2 groups. In MG (n = 29), EPM was successfully performed in 85 of 91 CS branches during CRT. A LV lead was successfully placed at the latest activated site guided by EPM in 27 (93.1%) patients. Compared with CG (n = 47), MG had a significantly higher rate (86.2% vs. 63.8%, P = 0.039) of response (>15% reduction in LV end-systolic volume) to CRT, a higher percentage of patients with clinical improvement of ≥2 NYHA functional classes (72.4% vs. 44.7%, P = 0.032), and a shorter QRS duration (P = 0.004). CONCLUSIONS: LV lead placed at the latest activated site guided by EPM resulted in a significantly greater CRT response, and a shorter QRS duration.

Effects of Exercise on Stress-induced Attenuation of Vaccination Responses in Mice.

Studies suggest that exercise can improve vaccination responses in humans. Chronic stress can lead to immunosuppression, and there may be a role for exercise in augmenting immune responses. PURPOSE: To investigate the effects of acute eccentric exercise (ECC) and voluntary wheel exercise training (VWR) on antibody and cell-mediated immune responses to vaccination in chronically stressed mice. We hypothesized that both ECC and VWR would attenuate chronic stress-induced reductions in vaccination responses. METHODS: Mice were randomized into four groups: control (CON), stress (S)-ECC, S-VWR, and S-sedentary (SED). Stressed groups received chronic restraint stress for 6 h·d, 5 d·wk for 3 wk. After the first week of stress, S-ECC were exercised at 17 m·min speed at -20% grade for 45 min on a treadmill and then intramuscularly injected with 100 µg of ovalbumin (OVA) and 200 µg of alum adjuvant. All other groups were also vaccinated at this time. Stress-VWR mice voluntarily ran on a wheel for the entire experiment. Plasma was collected before, and at 1, 2, and 4 wk postvaccination. Enzyme-linked immunosorbent assay was performed to analyze anti-OVA IgG and IgM antibodies. After 3 wk of chronic stress, all mice were injected with OVA into the ear to determine the delayed-type hypersensitivity. RESULTS: We found that chronic restraint stress significantly reduced body weight and caused adrenal hypertrophy. We also found both S-ECC and S-VWR groups had significantly elevated anti-OVA IgG (P < 0.05), whereas no significant differences between the two exercise groups. Neither S-ECC nor S-VWR altered anti-OVA IgM or delayed-type hypersensitivity responses compared with S-SED group. CONCLUSIONS: Acute eccentric exercise and voluntary exercise training alleviated the chronic stress-induced anti-OVA IgG reductions in vaccination responses.

Muscle Near-Infrared Spectroscopy Signals versus Venous Blood Hemoglobin Oxygen Saturation in Skeletal Muscle.

PURPOSE: The study aimed to examine the relationship between near-infrared spectroscopy (NIRS) signals and venous hemoglobin oxygen saturation (O2Hb%) and venous oxygen concentration (CvO2). METHODS: Gastrocnemius muscles (GS) in six dogs were surgically isolated and pump perfused. NIRS signals were recorded, and venous blood samples were collected at constant flow rates (control flow, high flow, and low flow) at rest as well as during electrically stimulated tetanic muscle contractions at rates of one contraction per 2 s (1/2 s) and two contractions per 3 s (2/3 s). Similar data were also collected at three different inspired O2 percentages (12%, 21%, and 100%) with constant blood flow. RESULTS: Complete data from five animals were analyzed; all data from one animal were deleted because of erratic oxy-NIRS signals. Venous O2Hb% ranged from 7.6% to 97.5% across the various experimental conditions. After the NIRS signals were normalized to the physiological range, a high linear correlation was seen between the deoxygenated heme signal (HHbMb%) and the venous O2Hb% (R = 0.92 ± 0.05), between the oxygenated heme signal (HbMbO2%) and the venous O2Hb% (R = 0.92 ± 0.03), between the HHbMb% and the CvO2 (R = 0.89 ± 0.06), and between the HbMbO2% and the CvO2 (R = 0.90 ± 0.05). The overall relationships between HHbMb%, HbMbO2%, and venous O2Hb% as well as between HHbMb%, HbMbO2%, and CvO2 were also linear and highly correlated with R values ranging from 0.81 to 0.90. CONCLUSION: In this controlled canine muscle model, NIRS signals are highly correlated with venous O2Hb% and CvO2 across a wide range of physiological conditions. The practical application of our results is that for an individual muscle or perhaps muscle group, normalized NIRS HHbMb and HbMbO2 signals accurately reflect the mean venous O2 saturation of the interrogated muscle tissue.

Hot Sauce: No Elimination of Vibrio vulnificus in Oysters.

Either Tabasco® sauce or a horseradish-based seafood cocktail sauce was placed on freshly shucked oysters which were incubated for 10 min on the half shell. Oysters were then assayed for numbers of Vibrio vulnificus cells present on the surface and within the oyster tissue, and the results compared to control oysters to which no sauce was added. Results indicated that Tabasco® sauce, but not the cocktail sauce, was highly effective in reducing the number of V. vulnificus cells present on the oyster meat surface. However, little reduction in the numbers of V. vulnificus cells present within the oysters was observed with either sauce. Our results suggest that hot sauces are not capable of significantly reducing the overall numbers of V. vulnificus cells associated with oysters, and that persons who are at risk for infection with this bacterium should continue to avoid the consumption of raw seafood, especially raw oysters.

Value of Cellobiose-Polymyxin B-Colistin Agar for Isolation of Vibrio vulnificus from Oysters.

Twenty-eight samples, comprising a total of 224 oysters, were examined for the presence of Vibrio vulnificus . Oyster homogenates were plated onto cellobiose-polymyxin B-colistin (CPC) agar or V. vulnificus enumeration (VVE) agar, with subsequent hybridization with a gene probe specific for this pathogen. Of over 3,500 cellobiose-positive colonies initially tested from CPC agar, 28.7% could be identified as V. vulnificus on the basis of probe hybridization. Of the 19,000 colonies developing on VVE agar, only 2.8% were identified as this species. When in subsequent CPC agar studies colony morphology as well as color was considered, 81.6% of over 1,000 colonies probed proved to be V. vulnificus . We conclude that CPC agar is highly selective for this pathogen, and may be effectively employed in monitoring studies to determine levels of this bacterium in molluscan shellfish.

Effects of GRAS Compounds on Natural Vibrio vulnificus Populations in Oysters.

Vibrio vulnificus is a bacterium indigenous to estuarine waters and is known to be a significant human pathogen. Infections are generally associated with the consumption of raw shellfish, especially oysters. We have previously determined that a variety of FDA-approved food preservatives were effective agents in causing lethality of V. vulnificus in vitro. In the present study we tested the effects of these compounds in treating natural oysters and found that diacetyl at concentrations of 0.05% or greater could significantly decrease the number of V. vulnificus naturally present in oysters. Lactic acid and BHA were found not to be effective at concentrations up to 0.05%. We conclude that diacetyl is a possible antimicrobial agent for this organism that might be used in shellfish stock.