Edo A. van der Velde

Reproducibility of MRI-derived measurements of right ventricular volumes and myocardial mass

Magnetic resonance (MR) imaging has been shown to provide accurate measurements of right ventricular (RV) volumes and myocardial mass. The purpose of this study was to evaluate the reproducibility of MR imaging, which in clinical practice may be as important as its absolute accuracy. The reproducibility of MR imaging measurements of the right ventricle was assessed by analyzing 40 serial functional MR imaging examinations of the right ventricle with variance component analysis. Standard deviations and 95% ranges for change were: for RV myocardial mass, 5.9 and 16 g; and for RV ejection fraction, 6.0% and 16%, respectively. Reproducibility was similar for cine and spin-echo MR imaging. The intraobserver and interobserver errors were especially large, indicating that observer subjectivity is the limiting factor in the interpretation of the MR images. This study suggests that the reproducibility of RV measurements is adequate to detect RV hypertrophy and a low ejection fraction in the individual patient. For accurate follow-up examinations, whereby smaller changes are to be detected, the reproducibility of MR imaging measurements may not be sufficient. More effort is needed to improve the reproducibility of MR imaging measurements.

Echo planar MRI of the heart on a standard system : Validation of measurements of left ventricular function and mass

OBJECTIVE Our goal was to validate cardiac measurements derived from multishot echo planar MRI (EPI) as compared with the well validated conventional GRE technique. METHOD Ten healthy subjects underwent breath-hold EPI and non-breath-hold GRE imaging in the short axis orientation of the left ventricle (LV) on a standard 1.5 T MR system. Ten section levels were obtained to encompass the entire LV. Measurements were obtained of end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), LV mass, time to end-systole (TES), and peak filling rate (PFR). Analysis of variance was performed to determine agreement between GRE- and EPI-derived measurements. RESULTS The acquisition time for EPI was much shorter than that for GRE (2.5 vs. 15 min). Both imaging techniques yielded good quality images allowing LV volumetrics. Agreement between GRE and EPI was best for measurements of EDV, SV, and LV mass; somewhat less agreement was found for ESV, EF, TES, and PFR. The intraobserver variability for measuring TES and PFR was higher for GRE than EPI (one sided F test; critical values at p = 0.05 were > 3.18). CONCLUSION Multishot EPI of the heart provides accurate measurements of LV function and mass in a time-efficient manner.

Assessment of left ventricular volume and mass by cine magnetic resonance imaging in patients with anterior myocardial infarction intra-observer and inter-observer variability on contour detection

Remodeling of the left ventricle after myocardial infarction can be documented by calculation of left ventricular volume and mass, using endocardial and epicardial tracings of multilevel multiphase short-axis cine magnetic resonance (MR) imaging series. We assessed left ventricular volume and mass from 8 slices and during 12 phases of the cardiac cycle in seven patients with an anterior wall myocardial infarction; one patient was studied twice, leaving eight MR examinations to be evaluated. Purpose of this study was to assess the intra-observer and interobserver variability of epicardial volume, endocardial volume, and left ventricular mass from contours manually traced by two independent observers. For the eight MR examinations, epicardial volume was found to be 292 ± 51 ml (mean ± SD) at end-diastole, which decreased to 237 ± 55 ml at end-systole. Endocardial volume was 141 ± 31 ml at end-diastole, which decreased to 79 ± 27 ml at end-systole. Left ventricular ejection fraction was 45 ± 8%. Mean left ventricular mass, when averaged over all patient studies and all phases, was 159 ± 30 g. Intra-observer and inter-observer variability were found to be 3.5% and 5.2% for endocardial volume, 2.0% and 2.5% for epicardial volume, and 3.6% and 3.6% for left ventricular mass, respectively. The contour analysis showed a statistically significant phase effect in the endocardial contour in the midventricular slices, which was resolved after establishing a more precise definition for the tracing of the endocardial border. In conclusion, left ventricular volume and mass in patients with an anterior wall myocardial infarction can be assessed with high reproducibility and relibility from manual contour tracings. A precise protocol for the definition of endocardial and epicardial contours is required to obtain reproducible and reliable results.

Caspase-3 activity as a prognostic factor in colorectal carcinoma

Several techniques to determine apoptotic frequencies in tumors have been described. In this study, we report that biochemical detection of enzymatic caspase-3 activity is a simple and quantitative technique to measure apoptosis in colorectal tumor cells. The relevance of the level of apoptosis in colorectal cancer for the clinical course remains unclear. Therefore, we studied the correlation between caspase-3 activity and prognosis of the disease in relation to different factors known to be involved in apoptosis induction. High caspase-3 activity significantly correlated with a higher risk of recurrence and was preferentially found in tumors of the right side of the colon. No correlation was detected between high caspase-3 activity and altered protein expression of p53, β-catenin, or proteins of mismatched repair genes. This indicates that high caspase-3 activity has no evident correlation with the genetic Wnt-signaling or the mismatch repair mutational pathways. The caspase-3 activity significantly correlated with CD57+ tumor infiltrating cells. Therefore, high caspase-3 activity in right-sided tumors might be induced by a specific lymphocytic reaction.

Submersion in The Netherlands: Prognostic Indicators and Results of Resuscitation

STUDY OBJECTIVES To analyze prognostic indicators and the outcome of resuscitation in submersion victims (drowning and near drowning). DESIGN Retrospective study. SETTING Intensive and Respiratory Care Unit. Between January 1, 1979, and December 31, 1985, 87 submersion victims were admitted. The files of 83 victims were available for statistical analysis. There were 66 male victims and 17 female victims; the average age was 31.4 +/- 25.8 years. There were ten salt water and 73 fresh water submersions. MEASUREMENTS AND MAIN RESULTS Predictors for better survival potentials were a young age, submersion of less than ten minutes, no signs of aspiration, and a central body temperature of less than 35 C at admission. We did not detect factors that accelerated a decrease in core body temperature at admission and assume that lethal hypoxia had preceded protective hypothermia in our submersion victims. The Orlowski score had a predictive value but at the same time we found nonindependent indicators in this score. Neurologic outcome in our patients, who were not treated according to a brain protection protocol, was not worse than the outcome published by authors who have used such a protocol. Thirty-three percent of the victims with a cardioventilatory arrest (15) and all victims with a ventilatory arrest (11) survived resuscitation and were discharged. Five nonarrest victims died due to late complications. CONCLUSION This study shows that no indicator at the rescue site and in the hospital is absolutely reliable with respect to death or survival.

Somatosensory evoked potentials in Huntington's chorea.

Somatosensory evoked potentials were measured in 21 patients with Huntingtons chorea and 12 controls. Central brain conduction time was normal. Early cortical component amplitudes were reduced in the patient group, latencies were normal. These abnormalities probably can be attributed to cortical dysfunction in Huntingtons chorea. No indication of brain-stem dysfunction was found.

Submersion cases in the Netherlands

Epidemiologic analysis of submersion cases admitted to the intensive and respiratory care unit showed that several interrelated factors preceded submersion. Accidental submersion and traffic accidents represented one third of the causes of submersion. Other relevant causes were illness (29.9%), psychosocial causes (20.1%), alcohol (18.1%), and suicide (9.1%). Age distribution, gender, and mortality rate were different in each group. Young age, submersion during recreational activities, summer months, and normothermia were epidemiologic factors with a favorable prognosis. Our data were compared with national data. WHO-ICD code 994.1 (drowning and nonfatal submersion) is the best entrance for epidemiologic analysis. Five hundred twenty deaths and 690 hospital admissions due to submersion occur in The Netherlands each year. About 460 victims die before they reach a hospital.

On the reliability of non‐metrical morphological sex determination of the skull compared with that of the pelvis in The Low Countries

In order to study the suitability of the skull for sex determination, a sample of 202 adult human skeletons with pelves was analysed according to the recommendations of the Workshop of European Anthropologists (1980). The remains originated from citizens of the medieval city of Dordrecht in The Netherlands (AD 1275–1572). Sex was determined by means of non-metrical morphological sex-descriminant features of the skull (cranium plus mandible) and of the separate cranium and separate mandible, and compared against determination made using the pelvis. The reliability of the pelvic sex determination was verified by evaluating the position of the lowest intermediate frequency of the bimodal distribution of the degrees of sexualization of the pelvis. Contingency diagrams and tables were drawn with respect to the sex diagnosis and the degree of sexualization of (i) the skull (cranium plus mandible) and related pelvis, (ii) the cranium and related pelvis, and (iii) the mandible and related pelvis. It was concluded that sex diagnosis using the skull, cranium and mandible corresponded to that using the pelvis in 96.2 per cent (N=106), 95.7 per cent (N=140) and 69.5 per cent (N=118) of the cases, respectively. Notably, in the case of female pelves (N=64), 51.6 per cent of the related mandibles were diagnosed as ‘male’. Therefore a caveat must be entered in the use of the mandible for the determination of sex, because in the Low Countries it was found to lack reliability.

Determinants of vibration perception thresholds in IDDM and NIDDM patients

The relative influence of diabetes mellitus-related and physiological factors on vibration perception thresholds was assessed in 353 patients in a hospital-based setting (173 insulin-dependent and 180 non-insulin dependent patients, aged 51.1 +/- 15.9 years) and 80 healthy controls (aged 43.3 +/- 15.2 years) employing a Biothesiometer. Vibration perception thresholds were bilaterally measured at the thumbs, medial malleoli and halluces. Sixty (17.0%) older patients had off-scale thresholds (> 50 V). As no systematic side differences were found, values of contralateral sites were averaged. Considering the effects of age, height, gender and skin temperature in controls, age accounted for 46.7 and 52.2% threshold variance at the ankles and halluces, respectively, while height explained 5.1 and 5.1%, respectively. At the thumbs, only age was of relevance. Age relationships with vibration thresholds in health did not differ from published reports at any site. In the patient group, influences of age, height, gender, skin temperature, years from diagnosis, HbAlc, serum creatinine, drop in systolic blood pressure on standing, and ankle/arm blood pressure indices were assessed for each type of diabetes. For both types, age and height again had relevant effects at the lower extremities as did age and gender at the thumbs. Skin temperature was only marginally significant at the halluces of NIDDM patients. Of the disease-related factors, HbAlc had the strongest effect: for both IDDM and NIDDM higher levels were associated with lower vibration sensitivity. Increasing disease duration led to significantly higher thresholds in IDDM patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Endogenous natural killer cells do not play a role in antitumor effects induced by interleukin-2 in a syngeneic rat colon tumor model

Abstract Previous experiments in a syngeneic rat liver tumor model using the colon adenocarcinoma CC531 demonstrated that injection of interleukin-2 (IL-2) induced significant antitumor responses. Furthermore, it was found that this treatment strategy was accompanied by an increase in the number of natural killer (NK) cells in and around the tumor. In the present study, the role of endogenous NK cells in IL-2-mediated antitumor responses was further elucidated by depleting tumor-bearing rats of NK cells, using the anti-CD161A mouse IgG1 antibody 3.2.3. Rats were depleted either after or prior to tumor induction and subsequently treated with IL-2. The results demonstrated that depletion of NK cells in tumor-bearing rats did not influence IL-2-induced antitumor effects. In addition, injection of IL-2 in NK-cell-depleted rats induced repopulation of NK cells in the peripheral blood from 3 days on and further after the last injection with IL-2. Therefore, the possibility cannot be excluded that de novo recruited NK cells play a role in attaining IL-2 mediated antitumor effects, but NK cells, which were present before or during the start of IL-2 therapy, were not relevant.