Repolarization changes induced by mental stress in normal subjects and patients with coronary artery disease: effect of nitroglycerine.

OBJECTIVES: Mental stress can significantly affect ventricular repolarization, which could potentially trigger arrhythmias. We compared the effect of mental stress on repolarization indexed by the amplitude and area of the T wave in patients with coronary artery disease (CAD) and healthy subjects. METHODS: Fourteen healthy controls (11 M, mean age 42 years) and 14 patients with stable CAD (12 M, mean age 64) underwent a mental stress protocol consisting of mental arithmetic followed by a speech (5 minutes each), which was performed on two occasions following either nitroglycerine (NTG) or placebo. Multiple 12-lead electrocardiograms were acquired and repolarization was analyzed using automatically measured T wave amplitude (T(amp)) and area (T(area)). RESULTS: When preceded by placebo the overall effect of mental stress, whether induced by arithmetic or speech, was significantly different in CAD patients compared with controls, with a decrease in T(amp) and T(area) in controls and an increase in patients; e.g., change in T(amp) during arithmetic -20 +/- 3 microV in controls versus 4 +/- 2 microV in patients, p < .001, and during speech -9 +/- 3 microV in controls versus 7 +/- 1 microV in patients, p < .001. Following NTG, the effect of stress on repolarization was similar in the 2 groups, with a reversed effect, i.e., decrease instead of increase in T(amp) and T(area) in CAD patients. CONCLUSIONS: The effect of mental stress on ventricular repolarization is significantly different in CAD patients compared with healthy controls. These differences are considerably reduced by NTG.

Hospitals with more-active participation in conducting standardized in-situ mock codes have improved survival after in-hospital cardiopulmonary arrest.

AIM: The American Heart Association (AHA) and the Institute of Medicine have published a national "call-to-action" to improve survival from in-hospital cardiopulmonary arrest (IHCA). Our aim was to determine if more-active hospital participation in standardized in-situ mock code (ISMC) training is associated with increased IHCA survival. METHODS: We performed an ecological study across a multi-state healthcare system comprising 26 hospitals. Hospital-level ISMC performance was measured during 2016-2017 and IHCA hospital discharge survival rates in 2017. We performed univariate and multivariate analysis of the hospital-level association between more-active ISCM participation and IHCA survival, with adjustment for hospital expected mortality as determined by a commercial severity scoring system. Other potential confounders were analyzed using univariate statistics. RESULTS: Hospitals with more-active ISMC participation conducted a median of 17.6 ISMCs/100 beds/year (vs 3.2/100 beds/year in less-active hospitals, p = 0.001) in 2016-2017. 220,379 patients were admitted and 3289 experienced IHCA in study hospitals in 2017, with an overall survival rate of 37.4%. Hospitals with more-active ISMC participation had a mean IHCA survival rate of 42.8% vs. 31.8% in hospitals with less-active ISMC participation (p < 0.0001), and a significantly reduced odds ratio (OR) of 0.62 for IHCA mortality (95% CI: 0.54-0.72; p < 0.0001) which was unchanged after adjustment for hospital-level expected mortality (adjusted OR: 0.62; 95% CI: 0.54-0.71; p < 0.001). CONCLUSIONS: Hospitals in our healthcare system with more-active ISMC participation have higher IHCA survival. Prospective trials are needed to establish the efficacy of standardized ISMC training programs in improving patient survival after cardiac arrest.

Superconducting RF coils for clinical MR imaging at low field.

RATIONALE AND OBJECTIVES: A number of recent reports in the MRI literature have established that substantial signal-to-noise ratio (SNR) gains can be achieved with small samples or low resonance frequencies, through the use of high-quality factor high-temperature superconducting (HTS) RF receive coils. We show the application of HTS coils to the imaging of human subjects with improved SNR compared with copper coils. MATERIALS AND METHODS: HTS coils were constructed from 7.62-cm YBa2Cur3O7-delta thin films on LaAlO3 substrate and cooled in a liquid nitrogen cryostat. Human and phantom images were acquired on a 0.2-T scanner. The SNR improvements compared with equivalent-sized copper coils are reported. RESULTS: SNR gains of 2.8-fold and 1.4-fold were observed in images of a phantom acquired with an HTS coil versus a room temperature copper coil and a liquid nitrogen-cooled copper coil, respectively. Preliminary results suggest higher image quality can be obtained in vivo with an HTS coil compared with copper coil imaging. Images of human orbit, brain, temporomandibular joint, and wrist are presented. CONCLUSION: The experimental results show that benefits can be expected from application of HTS surface coils in human MR imaging with low-field scanners. These potential benefits justify the continued development of practical HTS coil imaging systems despite the considerable technical difficulties involved in cryostat and coil design.

Elevated expression of TGF-beta1 in head and neck cancer-associated fibroblasts.

Head and neck cancers are characterized by a vigorous desmoplastic response, but the contribution of stromal-derived growth factors to the tumor microenvironment is poorly understood. We evaluated the expression of stromal growth factor expression in head and neck squamous cell carcinoma (HNSCC) in normal and tumor-associated stromal cells. Stromal tissue was isolated from epithelial cells with laser capture microdissection (LCMD) and analyzed by cDNA array for the expression of TGFalpha, TGF-beta1, HGF, PDGF-alpha, IGFII, bFGF, aFGF, VEGFC, and VEGF. Primary fibroblasts were isolated in vitro from HNSCC tumors, adjacent histologically normal mucosa, and skin in vitro. Fibroblast populations were assessed for TGF-beta1 expression by ELISA and luciferase reporter assay to assess protein expression. We identified TGF-beta1 and IGFII overexpression in normal and tumor-associated stromal cells; however, only TGF-beta1 was significantly overexpressed (3.4-fold) in tumor-associated stroma. Assessment of carcinoma-associated fibroblasts (CAFs), normal dermal fibroblasts (NDFs), and normal mucosal fibroblasts (NMFs) in propagated fibroblasts demonstrated persistently elevated levels of TGF-beta1 in CAFs compared to NMF and NDF populations. Elevated levels of TGF-beta1 were identified in the stromal compartment of HNSCC tumors compared to normal mucosa by immunohistochemical analysis. These results suggest that TGF-beta1 mRNA and protein is specifically upregulated in CAFs in vitro and in vivo.

Ratings of perceived exertion and muscle activity during the bench press exercise in recreational and novice lifters.

This study examined ratings of perceived exertion (RPE) and electromyography (EMG) during resistance exercise in recreational and novice lifters. Fourteen novice (age = 21.5 +/- 1.5 years) and 14 recreationally trained (age = 21.9 +/- 2.2 years) women volunteered to perform the bench press exercise at 60 and 80% of their 1 repetition maximum (1RM). RPE and EMG were measured during both intensities. Statistical analyses revealed that active muscle RPE increased as resistance exercise intensity increased from 60% 1RM to 80% 1RM (12.32 +/- 1.81 vs. 15.14 +/- 1.74). Integrated EMG also increased as resistance exercise intensity increased from 60% 1RM to 80% 1RM (in the pectoralis major; 98.62 +/- 17.54 vs. 127.98 +/- 29.02). No significant differences in RPE or EMG were found between novice and recreational lifters. These results indicate that RPE is related to the relative exercise intensity lifted as well as muscle activity during resistance exercise for both recreational and novice lifters. These results support the use of RPE as a method of resistance exercise intensity estimation for both types of lifters.