Increased risk of heart valve regurgitation after mediastinal radiation for Hodgkin's disease: an echocardiographic study.

OBJECTIVE: To assess by echocardiography the occurrence and degree of late cardiac sequelae after treatment for Hodgkin's disease by radiation and chemotherapy. PATIENTS AND METHODS: In Norway from 1980 to 1988, 129 patients < 50 years old with Hodgkin's disease had curative treatment with mediastinal radiation, with or without chemotherapy. 116 (90%) of these patients (mean (SD) age 37 (7) years, 67 males) were examined by echocardiography 5-13 years after treatment. 40 healthy individuals (mean (SD) age 40 (11), 20 males) were examined as controls. All those examined were in regular sinus rhythm. RESULTS: Grade > 1 (scale 0-3) aortic and/or mitral valvar regurgitation was found in 24% of the patients (15% aortic, 7% mitral, and 2% aortic+mitral), affecting 46% of the females v 16% of the males (P < 0.001). Female gender was a significant risk factor for aortic and mitral regurgitation (odds ratio 4.7, 95% confidence interval 2.0 to 11.2), whereas age, period of follow up, radiation dose, and chemotherapy were not. Thickened pericardium was diagnosed in 15% of the patients. No risk factors were identified. No cases of pericardial thickening or valvar regurgitation grade > 1 were recorded in the control group. Mean values for measured and calculated indices of systolic and diastolic function were within the normal range for patients and controls. The patients had reduced E/A ratio compared with the healthy controls (E/A 1.1 v 2.0, P < 0.001). CONCLUSIONS: Abnormal left sided valvar regurgitation was detected in one fourth of the patients, affecting the aortic valve in more than half of the cases. Females had an increased risk of valvar regurgitation. Echocardiographic screening after high-dose mediastinal radiation is recommended.

Separation and characterization of oligomers by reversed-phase high-performance liquid chromatography: a study on well-defined oligothiphenes.

Reversed-phase high-performance liquid chromatography (RP-HPLC) was used for the separation of 3-hexylthiophene oligomers in the range of 3 to 30 monomeric units, while systematically varying stationary and mobile phases. A set of different columns was chosen, covering a broad range of silica types, pore sizes and bonding chemistry. Mobile phases of tetrahydrofuran (THF) combined with water, acetonitrile (ACN) or methanol (MeOH) were used. Although differences between columns were small, a higher selectivity correlated with a lower hydrophobicity parameter from the Galushko column test. The model of Jandera, based on the linear solvent strength model of Snyder, was used to describe the retention of the oligomers in gradient mode. This gave information about selectivities on different stationary phases similar to the hydrophobicity parameter. Contrary to the stationary phase, the mobile phase had a major influence on the selectivity. The THF-water combination gave much higher selectivities compared to THF combined with MeOH or ACN. Using the aqueous mobile phase even enabled separation of different isomers. Determination of thermodynamic parameters for the model compounds showed that retention of the different isomers was mainly determined by the orientation of the side chains at both ends of the chain. An additional repeating unit in the middle of the polymer backbone gave a similar contribution to retention, irrespective of the orientation of its side chain. Three model isomers were separated by preparative RP-HPLC and identified by proton nuclear magnetic resonance spectroscopy. The combination of subsequent preparative size-exclusion chromatography, RP-HPLC and matrix-assisted laser desorption ionization time-of-flight mass spectrometry enabled the identification of the two major oligomeric series in the sample as the regioregular product with one bromine end group and, in smaller amounts, a regioirregular product with two bromine end groups. reserved.

Repeatability of measurements of pulmonary venous flow indices.

We investigated the measurement repeatability of four pulmonary venous flow indices. The indices were measured on 45 anonymised, transthoracic Doppler recordings of adequate technical quality. Measurements were taken by two independent observers, and repeated after 10 days. Plus/minus the repeatability coefficient, which was used to quantify repeatability, gives the 95% probability limits for random variation between repeated measurements. The index D-diff, which is the difference in duration of the pulmonary venous flow reversal during atrial systole and the transmitral A-wave, had repeatability coefficients of 50 and 57 ms intra- and inter-observer. For the fraction of antegrade pulmonary venous flow during ventricular systole, the coefficients were 12 and 13 percentage points, but improved to 6 and 7 among the high-quality recordings. The retrograde pulmonary venous flow during atrial systole as a fraction of the antegrade flow, had coefficients of 5 percentage points both intra- and inter-observer. The coefficient for the peak velocity of retrograde pulmonary venous flow was 0.05 m/s intra- and inter-observer. Thus, the systolic fraction was the only index that showed a satisfactory repeatability. We suggest that if the other indices are used, measurements should be taken by a blinded observer to avoid observer bias.

Influence of heart rate and left atrial pressure on pulmonary venous flow pattern in dogs.

In six open-chest anesthetized dogs we investigated the effect of heart rate (HR) on the relationship between left atrial pressure (LAP) and pulmonary venous flow (QPV). QPV was measured by ultrasonic transit time during volume loading and right atrial pacing. Consistent with previous studies, we found a negative correlation between LAP and mean flow rate during atrial systole divided by mean flow rate in the R-R interval. However, this relationship was shifted upward by tachycardia. The QPV maximum amplitude divided by mean flow rate in the R-R interval increased with loading but decreased with tachycardia. mean flow rate during ventricular systole divided by mean flow rate during the R-R interval increased with both loading and tachycardia. Regression coefficients for HR and LAP as predictors of these indexes were all significantly different from zero (P = 0.0001). We conclude that HR significantly influences the relationship between the QPV pattern and LAP. This could be a limitation of the pulmonary venous flow pattern as an indicator of left ventricular diastolic function.