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Biomedical subjects

H Schlebusch

Publications and source records attributed to H Schlebusch.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Significance of microproteinuria for early detection of hypertension-induced end organ damage].

To investigate the clinical importance of microproteinuria, we examined the prevalence of microproteinuria and its relation to cardiac structural adaptation in 80 male, middle-aged patients with essential hypertension. Patients with secondary causes of hypertension were ruled out. 14 out of 80 hypertensives (18 percent) were found to have microproteinuria defined as "negative" for urinary protein excretion in the conventional test, but "positive" (above the upper normal limit) in the 24-hour urine samples. Patients with microproteinuria had a similar age and body weight, but a higher systolic and diastolic pressure (161 +/- 14/104 +/- 12 vs 148 +/- 14/97 +/- 9 mmHg, p less than 0.02) and greater creatinine clearance (163 +/- 36 vs 136 +/- 33 ml/min, p less than 0.01) than those with normal protein excretion. Also, hypertensives with microproteinuria had a greater left ventricular mass (241 +/- 57 vs 207 +/- 45 g, p less than 0.05) and greater cross sectional area (22.2 +/- 2.8 vs 20.5 +/- 2.9 cm2, p less than 0.05) evaluated by 2-D guided M-mode echocardiography than the control group. A positive Sokolow-index was more prevalent in patients with microproteinuria than in those without (x2 = 6.2, p less than 0.02). Patients with essential hypertension and microproteinuria (prevalence 21 per cent) were characterized by a higher arterial pressure, by a higher degree of echocardiographic and electrographic evidence of left ventricular hypertrophy. Thus, microproteinuria might serve as a marker for early target organ damage in essential hypertension.

Adult↗
PubMed1990

Comparison of five routine methods with the candidate reference method for the determination of bilirubin in neonatal serum.

Using five routine methods and the candidate reference method of Doumas (Clin. Chem. 31, 1779-1789 (1985)), total bilirubin was determined in 77 neonatal serum samples (concentration range 63-444 mumol/l, average value 227 mumol/l). Four of the routine methods (Jendrassik & Grof's (Biochem. Z. 297, 81-89 (1938)) method, Hertz's (Scand. J. Clin. Lab. Invest. 33, 215-230 (1974)) method, the bilirubinometer procedure, and the method employing 2,5-dichlorophenyldiazonium (Scand. J. Clin. Lab. Invest. 29, Suppl. 126, Abstr. 11. 12. (1972]) gave values that were generally higher than those of the reference method. In contrast, the results from Vink's (Clin. Chem. 34, 67-70 (1988] direct spectrophotometric method differed only negligibly from those of the reference method. The accuracy of Jendrassik & Grof's method, and to a limited extent that of the 2,5-dichlorophenyldiazonium method, can be improved by redetermination of the molar absorption coefficient, or by using a standard containing a matrix of human albumin, with an assigned value determined by the reference method. It was found that Hertz's direct spectrophotometric method can be replaced by that of Vink. The accuracy of the bilirubinometer results could be improved only by using calibrators with assigned values specific for the bilimeter, or by calibration with a serum pool.

Bilirubin↗
PubMed1990

Accumulation of pollutants in the genital tract of sterility patients.

In order to assess the burden of environmental pollutants in the genital tract, 12 different chlorinated hydrocarbons were determined in 152 samples of follicular, seminal and cervical fluids from sterility patients in the in vitro fertilization programme at the Centre for Obstetrics and Gynaecology of the University of Bonn. The lowest concentrations were found in the follicular fluids of patients who eventually became pregnant by in vitro fertilization. Higher concentrations were found in patients with sterility of unknown origin. Concentrations in the cervical secretion were up to twenty times higher than those in the seminal or follicular fluids. The results show that considerable concentrations of chlorinated hydrocarbons may be present in parts of the reproductive system, and that these compounds accumulate in the reception zone for spermatozoa. Certain pollutants therefore probably contribute to infertility.

Cervix Uteri↗
PubMed1990

[Fructosamine reference ranges for pregnant patients and children determined using an improved NBT method].

Reference values for fructosamine in pregnancy show a decrease with progressing pregnancy, which can be explained by pregnancy-associated hemodilution. A normalization to 7.0 g/dl total protein leads to values independent of gestational age. For children and adolescents age-dependency of the reference range is abolished if values are related to total protein. More plausible values are obtained in longitudinal profiles if fluctuations of protein concentration are taken into account.

Adolescent↗
PubMed1989

[Pregnancy and labor in acute intermittent porphyria].

We report on the pregnancy and delivery of a 33-year old nullipara suffering from acute intermittent porphyria. Despite high risk of mortality and exacerbation of the disease, no complications occurred, since basic therapeutic principles were followed.

Acute Disease↗
PubMed1989

External quality assessment of absorbance measurements on spectral and spectral-line photometers.

From 1984-1987, 12 quality control surveys on photometric measurements were carried out in 600-800 laboratories. The participants measured the photometric absorbance of the control samples at 4 wavelengths of the mercury spectrum: 334.1 nm, 365.4 nm, 404.7 nm and 546.1 nm. The medians of the results were without exception lower than the target values, but only very few of them deviated more than 1%. The dispersion of the values did not follow a normal distribution. Two thirds of the values were concentrated within a very small range, while about 10% lay outside the 2- to 3-fold range. It was found that longer wavelengths resulted in a smaller dispersion of readings than shorter ones. Furthermore, precision showed a significant dependency on the absorbance readings of the samples, on the one hand, and on the different photometers, on the other.

Chemistry, Clinical↗
PubMed1989

Polychlorinated biphenyls: the occurrence of the main congeners in follicular and sperm fluids.

We have studied the presence of polychlorinated biphenyls in human body fluids associated with reproduction. Since the polychlorinated biphenyls represent a family of compounds, 3 of the main congeners of this family were selected for this study. The distribution of these 3 congeners was investigated in 37 specimens of follicular fluid and in 16 specimens of sperm fluid. Both fluids showed a similar, low contamination with total polychlorinated biphenyls (ca. 10 micrograms/kg on average), but it was evident that the follicular fluids preferentially accumulated the more highly chlorinated components. This finding must be taken into account when interpreting the concentration levels of the main congeners in relation to total pollution and the toxic potential of polychlorinated biphenyls.

Female↗
PubMed1988

External quality control in the determination of neonatal bilirubin. An approach to the improvement of results.

The reliability of bilirubin analyses is especially important in cases of neonatal hyperbilirubinaemia. However, when the means of the results of external quality control surveys and the method-dependent stated values for control sera were compared with reference method values, differences of up to 10% were found. Further inaccuracy arose from interlaboratory imprecision, which showed coefficients of variation of at least 7%, and from greater or lesser interference from contamination of samples with haemoglobin. The present work investigates whether the current situation can be improved by available means.

Bilirubin↗
PubMed1987

[PMN elastase in extracorporeal circulation procedures].

Proteolytic enzymes released by polymorphonuclear neutrophils are assumed to be important mediators in the development of shock-induced and sepsis-induced organ failure, especially of ARDS. The most remarkable of these enzymes is elastase because of its relatively high intracellular concentration and low substrate specificity. The release of elastase can be monitored by measuring the plasma concentration of elastase-proteinase inhibitor complex. In this study, the elastase concentration pointed towards side effects of methods of extracorporeal circulation. The elastase concentration rose more than sixfold in 20 patients during membrane oxygenation (mean time 124 min) and 15 patients during bubble oxygenation (mean time 77 min). We found that the elastase concentration was affected by the kind of foreign material surface, the time of perfusion and the perfusion volume. The comparison of in-vitro and in-vivo circulation underlines the importance of the terminal capillary bed (in the lung) and of a pre-existent activation of leukocytes, since elastase levels rose only insignificantly during in-vitro recirculation. These results confirm that extracorporeal circulation seems to be able to induce harmful disturbances of the ARDS type. This fact should be taken into consideration when using methods of extracorporeal gas exchange.

Adolescent↗
PubMed1985

Studies on the role of sodium- and potassium-activated adenosine triphosphatase inhibition in the pathogenesis of human hypertension. Changes in vascular and cardiac function following inhibition of the sodium pump in normotensive subjects and effects of calcium entry blockade.

An endogenous humoral factor which inhibits the sodium- and potassium-activated adenosine triphosphatase (Na-K-ATPase) enzyme in vitro has been incriminated recently of playing a pathogenetic role in experimental and human hypertension. The present study was therefore performed in six healthy volunteers to investigate the hemodynamic consequences of an inhibition of this enzyme by ouabain, a potent and specific inhibitor of Na-K-ATPase. In addition, the role of intracellular calcium as a potential mediator was studied indirectly by the administration of nifedipine, a potent calcium entry blocker with predominant vasodilator properties. Intravenous administration of 8.5 micrograms ouabain/kg body weight inhibited red blood cell (RBC) - Na-K-ATPase by 49% which was accompanied by a significant increase in RBC - ATP and a decrease in intracellular potassium concentrations. This enzyme inhibition resulted in a 24% increase in peripheral vascular resistance. The parallel decrease in cardiac output and heart rate, however, prevented a rise in arterial pressure. This increase in vascular resistance was completely abolished by pretreatment with nifedipine (10 mg orally). In the absence of an effect of nifedipine on Na-K-ATPase, its attenuation of the vasoconstrictor effect of ouabain suggests that the effects of ouabain on the vascular smooth muscle cell are mediated by intracellular calcium. These results demonstrate that inhibition of the Na-K-ATPase enzyme in vivo causes a marked peripheral vasoconstriction. They are also compatible with the concept that an endogenous inhibitor of Na-K-ATPase - in the presence of decreased baroreceptor reflex sensitivity due to blood volume expansion - may play a role in the pathogenesis of human arterial hypertension.

Adenosine Triphosphate↗
PubMed1985

[The ISE 2020 electrolyte analyzer: results of a multicenter evaluation].

The ISE 2020 electrolyte analyzer has been investigated within the framework of a multicentre evaluation in 5 laboratories. The users quickly learnt how to operate the instrument, and changes of personnel in the course of the trial had no influence upon the quality of the results. Regardless of the sample material (blood, serum, plasma) and the manner of introduction of the sample (manual or with the sampler), the in-series precision averaged 0.8% for sodium and 1.0% for potassium. The day-to-day precision was only slightly worse, at 1% (Na) and 2% (K). The recover, referred to the nominal values of control sera, averaged 100.3%. Investigations of linearity for potassium in the range from 0 to 12 mmol/l and for sodium in the range from 80 to 180 mmol/l confirmed a linear course of the measurements in the range of electrolyte concentrations of diagnostic interest. In extensive investigations by the testers with serum and plasma samples, the results showed good comparability with those from flame emission photometry. The mean values obtained by the two methods differed from one another only minimally in the case of sodium and potassium. The results with whole blood and with plasma prepared from it were in very close agreement. The ISE 2020 is regarded as highly suitable for routine work and emergency investigations in the central laboratory as well as for wards and operating rooms.

Anticoagulants↗
PubMed1984

[Comparison of various methods for determining glycosylated hemoglobins].

Determination of glycosilated haemoglobin (HbA1) has become an important parameter for the control of diabetes mellitus. Although several methods are available today, some are time consuming and complicated and may lead to differing results. Two methods, the thiobarbituric-acid (TBA) method and microcolumn chromatography, were compared with the reference method, high performance liquid chromatography (HPLC), with respect to precision, accuracy and practicability. Seventy different blood samples from diabetics were analysed. Using the TBA method, good results were achieved which were generally consistent with those of the reference method (r = 0.90); there were no significant differences in values determined with the two methods. However, the TBA method requires an inordinate amount of work. Microcolumn chromatography is better suited to the needs of physicians in private practice. Results with this method also correlate well with those of the reference method (r = 0.92) when the labile aldimine fraction has been removed by dialysis of the sample. Quality control can be performed using either lyophilized or deep-frozen control samples.

Chromatography↗
PubMed1984

Influence of intravenous Mg++ solutions on renal excretion of potassium, sodium, calcium, chloride, intraleukocytic potassium and peripheral vascular resistance: a metabolic and hemodynamic study in normal volunteers.

In an open randomized crossover trial 8 healthy male volunteers received an intravenous infusion of potassium chloride, potassium/magnesium chloride, potassium-(D,L)-aspartate, and potassium/magnesium-(D,L)-aspartate. Equimolar amounts of potassium (27.75 mmol) and magnesium (13.9 mmol) were given in a 500-ml volume during 24 h. During two 9-day periods subjects were maintained on a constant diet with a daily intake of 80 mmol potassium and 60 mmol magnesium. Infusions were administered on day 5 and 7 of each period. Serum and urine electrolyte concentrations as well as intraleukocyte potassium were measured before, during, and after the tests; cardiac output and systemic vascular resistance were determined by impedance cardiography. Potassium and magnesium containing solutions did not influence renal elimination of potassium, and also the circadian rhythm of potassium excretion did not show any change. The elimination of sodium, calcium, potassium, and chloride rose significantly over the corresponding control values during magnesium infusions, but not when potassium salts were given. The increase of calcium excretion after Mg++ is most probably due to suppression of parathyroid hormone. Intraleukocyte potassium was not affected significantly by the various infusions, indicating that intracellular compartments are completely filled. There was no evidence that the anion (D,L-aspartate or chloride) had a significant effect on all measured variables. Mean arterial blood pressure and peripheral vascular resistance were not altered significantly during the infusions.

Adult↗
PubMed1983

An improved method for the determination of potassium in leucocytes.

1. In twenty normal subjects and five patients with disturbances of potassium balance, the potassium concentration in leucocytes was measured by a modified technique. 2. The precision of the method was three to four times greater than that of techniques previously described, with a coefficient of variation for duplicate analyses of 2.3%. 3. A comparison between intraleucocyte potassium concentration and total body potassium in five patients with pathological alterations in their potassium balance showed that intracellular potassium concentration may reflect the clinical state better than total body potassium.

Adolescent↗
PubMed1983

[Biochemical findings in gestosis patients with pulmonary complications].

Lysosomal proteases from the granula of polymorphonuclear leucocytes play an important part in the development of the shock lung syndrome and its preliminary stages. If there is a local imbalance between the neutral proteinases (e.g. elastase) and its inhibitors, the interstitium consisting of collagenous fibres and glycosaminoglycanes is damaged. In 4 patients with gestosis and pulmonary complications it became evident that the plasma levels of the elastase-alpha 1-proteinase inhibitor complex correlate well with the clinical status and the x-ray findings. Significantly increased values are seen already prepartally; maximum values represent a severe interstitial oedema, and the drop of the values occurs parallel with the improvement of the clinical pattern. The increased consumption of inhibitors is expressed by the absence of the reactive increase of alpha 1-antitrypsin. By determining the elastase-alpha 1-PI complex it becomes possible to recognize the possible risk of development of an interstitial pulmonary oedema well in time, and the success of therapeutic measures is easily ascertained and controlled.

Adult↗
PubMed1982

[A new, sensitive haemagglutination inhibition test for the specific detection of human choriongonadotropine (HCG) in urine].

The reliability and clinical usefulness of a new pregnancy tube test with a sensitivity of 125 IU HCG/l was tested on 1142 urine samples. No false-negative results and 0.6% false-positive results were observed; a crossreaction with LH was seen above 1400 IU LH/l. In all cases of ectopic pregnancies (n = 49) the test yielded a positive result. In daily urine samples, collected during the luteal phase of the cycle, of 10 women who became pregnant, the test gave a positive result 13.6 days (on the average) after the rise of the basal body temperature. Especially in acute gynaecological emergencies the test is of value, because of its sensitivity and practicability.

Body Temperature↗