Differential birthweights and the clinical relevance of birthweight standards in a multiethnic society.

Using a computer-stored database, birthweights and related variables over 25,000 infants born in Amsterdam (The Netherlands) were analysed retrospectively. Only after allowing for maternal height, did the difference between mean birthweights of Dutch and Asian infants disappear, whereas Negroid and Mediterranean infants continued to show respectively lower and higher means than the others. These results confirm that the birthweight standards presently used are inappropriate for detection of deviant weight in non-Dutch groups.

Some characteristics of labor in ethnic minorities in Amsterdam.

A retrospective study of labor in immigrants, subdivided into Blacks, Asians and Mediterraneans (Turks and Moroccans) and autochthonous Dutch in Amsterdam over a 10-year period showed definite differences. The second stage was shortest in Blacks and Mediterraneans but they sustained perineal tears and episiotomies less frequently. Differences in positions at birth were small except for occipito-posterior position which was very rare in Asians and Mediaterraneans. The rate of cesarean section was highest and that of instrumental vaginal delivery lowest in Blacks, and latter being highest in Asians. Retained placenta occurred less often in immigrants than in Dutch.

[Doppler echocardiography determination of systolic and diastolic function in sequential and ventricular stimulation]. / Dopplerechokardiographische Bestimmung der systolischen und diastolischen Funktion bei sequentieller und ventrikulärer Stimulation.

In 16 patients with sequential pacing and partly impaired left-ventricular function (mean shortening fraction 23 +/- 7%), the flow through the mitral and aortic valves were studied with Doppler echocardiography at different AV-intervals, keeping heart rate constant at 70/min. The time-velocity integral of the early and late diastolic filling, the first one-third filling fraction, and the diastolic-filling time were found to be significantly dependent on the length of the AV interval (p less than 0.001). In the left ventricular outflow tract, the maximum stroke volume of 85.6 +/- 28.4 ml was measured at an AV interval of 200 ms. The stroke volume under VOO stimulation (70.5 +/- 24.1 cm) was 17% less (p less than 0.003). There was no correlation between the increase in stroke volume during sequential pacing and M mode or Doppler echocardiographic parameters. Thus, the haemodynamic benefit of sequential pacing cannot be predicted by echocardiography. Doppler echocardiography is useful for determining the AV interval leading to the maximal cardiac output at rest. In the Doppler echocardiographic assessment of left-ventricular function, the influence of the AV interval on diastolic-filling parameters must be considered.

Perinatal mortality in Curacao, Netherlands Antilles

The Perinatal Mortality Rate (PNMR) is considered to be an indicator of perinatal health. To ascertain the validity of the perinatal mortality statistics in Curacao, medical records and death certificates were reviewed over a five year period. Using a birth weight of 1,000 gm as a cut-off point, 366 foetal and first-week deaths were recovered from the statutory death certificates. Using similar criteria, 19 perinatal deaths, identified in the medical records, were not registered as such on the death certificates (registration failure 4.9 percent). Hence, the revised annual PNMR ranged from 19.0 to 31.2 per 1,000 births during the period 1979-1983. Additionally, the contribution of low birth weight (LBW)(<2,500gm) to perinatal mortality was examined during 1984-1985. LBW was associated with 68.6 percent of all perinatal deaths using a birth weight of 500gm as truncation point. However, it is argued that the high proportion of LBW to perinatal mortality is not the result of an adverse birth weight distribution of the Curacao population (AU)

The reliability of perinatal mortality statistics in The Netherlands.

All 13 hospitals in the municipality of Amsterdam cooperated in this study; labor ward records for the years 1981 and 1982 were personally searched for cases of perinatal death that corresponded with the World Health Organization definitions of perinatal mortality, presently applied in The Netherlands. The 360 cases that had apparently occurred in the Amsterdam hospitals were individually linked to the cases that had been entered into the national records at the Central Bureau of Statistics. The study established that the magnitude of underregistration of perinatal mortality is considerable (14.3%). Underregistration at the national level is due to underreporting by physicians and not due to errors in statistical bookkeeping. Underreporting is related to birth weight, that is, viability of the infant, and immigrant status of the mother. Recommendations are made to improve uniformity of notification criteria and reliability of perinatal mortality statistics.

[Effect of the calcium antagonist nisoldipine on electrophysiologic parameters in the human]. / Der Einfluss des Calciumantagonisten Nisoldipin auf elektrophysiologische Parameter beim Menschen.

We investigated the influence of nisoldipine, a new calcium antagonist, on sinus node function, intracardiac conduction times, and the refractoriness of different compartments of the heart. Three catheters were placed in the right heart: a quadripolar one in the high right atrium, a bipolar one in the His position, and one in the apex of the right ventricle. Nisoldipine given i.v. in a dose of 1.5 microgram/kg body weight shortened the sinus node cycle length and the sinus node recovery time by 10%. The rate corrected sinus node recovery time, the sinoatrial conduction time, and the intracardiac conduction times remained unaffected. The effective refractory period of the right ventricle decreased slightly but significantly. The refractoriness of the other compartments did not change significantly. Systolic blood pressure decreased by 6%, whereas diastolic blood pressure remained constant. Nisoldipine thus exhibits no major effects on electrophysiological parameters in man. The increase in heart rate is regarded as a sympathetic reflex mechanism due to the decrease of systemic resistance.

Machakos project studies. Agents affecting health of mother and child in a rural area of Kenya. XXII. Schistosomiasis transmission in relation to some socio-economic and other environmental factors.

A schistosomiasis research project, carried out in part of the Machakos area, yielded data by which it was possible to relate household egg outputs to some socioeconomic and other environmental variables. A significant negative correlation with schistosome scores was found for most variables when tested individually. Multiple regression analysis revealed a relatively strong relation with altitude and a much weaker association with some other variables. It is discussed whether the influence of altitude may be explained by differences in temperature, 'distance from infected water', or both. Furthermore it is hypothesized whether relations with social and economical variables are due to the fact that members of wealthier families stay away from contaminated water more often, have more knowledge of schistosomiasis and differ in hygienic behaviour.

[Elevated serum myoglobin in renal failure (author's transl)]. / Erhöhtes Serum-Myoglobin bei Niereninsuffizienz.

In 44 patients with chronic renal failure of varied etiology serum immunoreactive myoglobin was measured and compared to values obtained in patients with normal renal function. Irrespective of the underlying disease a highly significant linear correlation was found between serum immunoreactive myoglobin and serum creatinine concentration. In patients with serum creatinine concentrations above 550 mu mol/1 (6.2 mg%) serum myoglobin was as a rule elevated above the range found in the controls with normal renal function. This was also true in dialysis patients. These result demonstrate that serum myoglobin may only be used with restrictions in the diagnosis of myocardial infarction in patients suffering from advanced chronic renal failure.

The role of ATP and lactic acid for mitochondrial function during myocardial ischemia.

Phosphorylation rates of canine heart mitochondria isolated after various periods of myocardial ischemia after cardioplegic arrest were correlated with the myocardial ATP-, lactate- and undissociated lactic acid content as well as with interstitial H+-concentration. The following correlation coefficients were found: ATP: 0.87, lactate: 0.93, interstitial H+: 0.73. The calculated undissociated lactic acid content and the mitochondrial phosphorylation rate during ischemia showed a correlation coefficient of r = 0.95. Swelling measurements of mitochondria, isolated immediately after cardioplegic arrest, demonstrated that an undissociated lactic acid- and an ATP-concentration of 70 microM and 28 microM respectively are necessary for a half maximal swelling reaction under anaerobic conditions. The results suggest that the accumulation of undissociated lactic acid during myocardial ischemia could play an important role for mitochondrial damage in vivo.

Functional behaviour of isolated heart muscle mitochondria after in situ ischemia. Polarographic analysis of mitochondrial oxidative phosphorylation.

Heart muscle mitochondria with satisfactory functional parameters of oxidative phosphorylation and with morphologically intact structure were isolated from canine myocardium employing a modified KEA-medium (0.18 M KCl, 10 mM EDTA, 0.5% bovine serum albumin, pH 7.1) according to Sordahl and Schwartz (1). The functional behaviour of mitochondria was investigated after different durations of in situ ischemia (cardioplegia, 15 degrees C) and correlated with metabolic findings. During ischemia the following changes were seen: 1. Successive reduction of electron flow. 2. Relatively small impairment of phosphorylation efficiency. 3. Less damage of FAD- than NAD-catalyzed oxidative phosphorylation. 4. A marked increase of electron flow and thus recovery of phosphorylation rate even after longer ischemic periods by addition of cytochrome c. As important factors of accelerating mitochondrial impairment during ischemia the myocardial ATP decrease, the lactate and H+-activity increase are discussed.

[Comparison of tolerance to ischemia in human and animal myocardium during various forms of induced cardiac arrest (author's transl)]. / Vergleichende Untersuchungen zur Ischämietoleranz des isolierten menschlichen und tierischen Myokards bei verschiedenen Formen des künstlichen Herzstillstandes

In a total of 16 patients the tissue pH was determined on myocardium both during surgery and on isolated samples. Cardiac arrest was induced by hypothermal infusion cardioplegia and external cooling. In the isolated human myocardium section pH values were continuously determined at 15 degrees C. Parallel to these measurements samples were taken for electron microscopic examinations. In this way the pH limit under which the human myocardium cannot be revived could be visualized by additional morphologic examination. These results and those from the intrasurgical measurements with a fixed heart muscle surface probe were compared with each other and with results from animal experiments.

Myocardial resistance and tolerance to ischemia: physiological and biochemical basis.

This article is a short review of newer findings concerning the physiological and biochemical bases of the heart's tolerance to ischemia. The following themes are discussed. I. Energy-pool, energy-demand, and efficiency of anaerobic metabolism, the essential determinants of reanimation time and the heart's tolerance to ischemia. II. Experimental results of ischemic heart arrest and the heart arrest induced by a sodium-poor calcium-free, procaine-containing cardioplegic solution, developed by the author. III. Equivalents of function, metabolism and structure during the anaerobic period of the myocardium. IV. The myocardium's capability to recover in dependence on the metabolic state of ischemia and summary of the most important points of gaining a long time of tolerated ischemia. V. Survey and prospects.