Correlation between atrial and ventricular contractility a possible use of the atria to control the artificial heart

The possibility of using the atrial myocardium to control artificial ventricles is examined. Correlation was studied between the tension of the atrial wall and the tension and pressure in the ventricles during random variation of the cardiac rhythm was studied. Tension in the wall of the corresponding part of the heart was recorded by means of arch strain gauges and the intraventricular pressure by means of an electromanometer during catheterization of the chambers of the ventricles. The cardiac rhythm varied from 2.0 to 4.0 sec^–1. Correlation was demonstrated in the atria between the tension and interspike interval (coefficient of correlation 0.62±0.05). Close correlation was detected between tension in the atrial wall and the intraventricular pressure. The coefficient of correlation in this case varied from 0.713±0.09 to 0.874±0.02 depending on the mean duration of the interspike interval. Information on atrial contractions can be used to control an artificial heart.Institute of Organ and Tissue Transplantation, Ministry of Health of the USSR, Moscow. Laboratory of Biophysics of the Myocardium, Interregional Cardiac Surgical Center, Sverdlovsk. Translated from Byulleten Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 6, pp. 515–518, June, 1979.     

Effects of intermittent hypobaric hypoxia on blood lipid concentrations in male coronary heart disease patients

The objective of the study was to evaluate the effects of intermittent hypobaric hypoxia (IHH) on plasma lipid concentrations of male coronary heart disease (CHD) patients. Forty-six male coronary patients were enrolled in the study. Thirty had a history of myocardial infarction and 16 had ischemic episodes documented by ergometer testing or Holter monitoring. The patients underwent acclimation to hypoxia by means of a protocol of intermittent exposure in a hypobaric chamber. Lipid profiles, including coefficient of atherogenity (CA) by A.N. Klimov, were assessed at baseline, on completion of the study, and at 3-, 6-, and 10-month follow-ups. Total cholesterol decreased by 7% on completion of the IHH and by 9% at 3 months and persisted on that level to month 6. HDL levels increased by 12% at 3-month follow-up and remained significantly higher than baseline until month 6. LDL levels declined on completion of IHH, but the changes from baseline were most prominent at 3-month (13%) and 6-month (11%) follow-ups. Similar changes were found in levels of VLDL and TG. CA declined by 26% on treatment completion and by 37% at 3-month follow-up and increased to baseline at 10 months. No changes in lipid profiles were found in patients with CA < 3 (n = 22). In subjects with CA > 3 (n = 24), beneficial effects were more pronounced. IHH in CHD patients with abnormal lipid metabolism leads to favorable changes of plasma lipid patterns persisting to month 6 following IHH.     

Preparation of high specific activity tritium‐labelled leukotriene B4 suitable for radioligand binding assay

We describe a method of preparation of high specific activity tritium‐labelled leukotriene (LT) B₄ from [5,6,8,9,11,12,14,15‐³H] arachidonic acid (AA; 6.66 TBq/mmol) utilizing a LTB₄‐synthesizing enzyme system from rat basophilic leukemia (RBL‐1) cells. It was shown that both cyclooxygenase inhibitor indomethacin and adenosine 5′‐triphosphate induced [³H] AA transformation to [³H] LTB₄. In optimized conditions up to 15% of total radioactivity of the incubation mixture was present in [³H] LTB₄. A separation of [³H] LTB₄ from other labelled C_20:4 products was achieved by a three‐step reverse phase‐high‐performance liquid chromatography in methanol‐ and acetonitrile‐based solvent systems. [³H] LTB₄ was confirmed to be identical to the naturally occurring LTB₄ by a radioligand binding assay using a culture of HF1 cells that express a BLT₁ receptor. Copyright © 2008 John Wiley & Sons, Ltd.     

Arrhythmia in patients after heart transplantation

Holter monitoring was performed in 15 patients surviving over 3 months after homotopic cardiac transplantation. The frequency and types of arrhythmias occurring in the grafted innervated heart were studied according to its postoperative period duration. The follow-up lasted 3 to 29 months. Supraventricular arrhythmias were detected in 80%, whereas ventricular ones were found in 86.7%. Ventricular arrhythmias accompanied chronic graft rejection in 2 patients. It was ascertained that Holter monitoring was of greater diagnostic value than routine ECG recording. Innervation is not essential in the occurrence of cardiac arrhythmias.     

Two-Dimensional sixteen channel transmit/receive coil array for cardiac MRI at 7.0 T: Design, evaluation, and application

Purpose:

To design, evaluate, and apply a 2D 16‐channel transmit/receive (TX/RX) coil array tailored for cardiac magnetic resonance imaging (MRI) at 7.0 T.

Materials and Methods:

The cardiac coil array consists of two sections each using eight elements arranged in a 2 × 4 array. Radiofrequency (RF) safety was validated by specific absorption rate (SAR) simulations. Cardiac imaging was performed using 2D CINE FLASH imaging, T mapping, and fat–water separation imaging. The characteristics of the coil array were analyzed including parallel imaging performance, left ventricular chamber quantification, and overall image quality.

Results:

RF characteristics were found to be appropriate for all subjects included in the study. The SAR values derived from the simulations fall well within the limits of legal guidelines. The baseline signal‐to‐noise ratio (SNR) advantage at 7.0 T was put to use to acquire 2D CINE images of the heart with a very high spatial resolution of (1 × 1 × 4) mm³. The proposed coil array supports 1D acceleration factors of up to R = 4 without significantly impairing image quality.

Conclusion:

The 16‐channel TX/RX coil has the capability to acquire high contrast and high spatial resolution images of the heart at 7.0 T. J. Magn. Reson. Imaging 2012;36:847–857. © 2012 Wiley Periodicals, Inc.     

The Association of Intimate Partner Violence,Recreational Drug Use with HIV Seroprevalence among MSM

Intimate partner violence (IPV) has been significantly associated with HIV among heterosexual individuals. Yet a similar relationship has not been so clearly described among men who have sex with men (MSM). The aim of this study was to investigate the association of IPV with HIV seroprevalence among MSM. Participants consisted of 7,844 MSM clients who visited the Whitman Walker Clinic in Washington DC from 2000 through 2007, the majority of whom were Caucasian with a median age of 30. The univariate analysis showed that self-reported IPV was significantly associated with HIV (OR: 1.67, CI: 1.14–2.45) among the sampled MSM clients. However, when adjusting for sexually transmitted infection (STI) status and self-reported risk behaviors including recreational drug use, condom use, number of male sex partners, and having sex with a positive HIV partner, the association of IPV with HIV was not statistically significant. Results indicated that the strong independent association of recreational drug use with HIV seroprevalence decreased the association of IPV with HIV significantly (with recreational drug use, OR: 1.36, CI: 0.93–2.00 vs. without recreational drug use, OR: 1.51, CI: 1.03–2.22).     

The functional state of local immunity in the female genital tract during the HPV-infection

[ Objective] The study was aimed to assess the state of antigen-presenting cells (APC) and humoral immunity in the female genital tract during the HPV- infection. [Method] This study was conducted at t...