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Biomedical subjects

W Schulz

Publications and source records attributed to W Schulz.

At least 37 records · Page 2Linked to original sources
PubMed1992

[The size of the liver metastases in a low metastatic count. A quantitative study of postmortem livers].

In this postmortem study 34 livers with one or few "large" metastases (greater than 1 cm) were investigated for the presence of synchronous "small" metastases (less than 1 cm). A total of 671 metastases were investigated morphometrically. Of these, 134 were large and 537 were small according to the given definitions. The relation of large to small metastases was 1:4 and turned out to be relatively constant in most cancer types, except for colorectal cancers. The latter showed a relation of 1:1.6 which is more favourable for the detection of occult small secondaries. The results are discussed in the view of the preoperative diagnosis of liver metastases.

Autopsy↗
PubMed1991

Response of coronary arteries to nitrates, the EDRF-donor SIN-1, and calcium antagonists.

Intracoronary drug administration is an important tool to study coronary effects without interaction of systemic effects. The difficult methodological aspects and the results of clinical trials in which the effects of vasodilating drugs were evaluated with respect to coronary dilatation are reviewed. Major (coronary substrate, study design) and minor (measuring devices, methods of evaluation) methodological problems make it difficult to precisely evaluate pharmacological effects such as dose-response relationship, duration of action, and selective responses, and to compare the effects of different drugs. From a clinical point of view, knowledge of the maximal effect (EDmax) in coronary stenoses and the duration of action is essential. NO-donors tend to act stronger than CA-channel blockers which may be attributable to their different modes of action. Among those NO-donors investigated, SIN-1 showed stronger effects than nitroglycerin. Only with SIN-1 were maximal effects obviously achieved. The additional administration of nitroglycerin or nisoldipine never led to a more prominent dilatation. In coronary stenoses, the underlying morphology causes a wider range of responses than is seen in normal segments: deendothelialized stenoses with high coronary tone show a larger dilatation, while fully sclerotic stenoses may not react.

Calcium Channel Blockers↗
PubMed1991

Reduced lipid concentrations during four years of dialysis with low molecular weight heparin.

Heparin is used as standard anticoagulant in the extracorporeal circuit of hemodialysis. Widespread use of this drug revealed several potentially adverse effects, such as release of lipoprotein lipase and hepatic lipase from the endothelial surface. Recently it was found that anticoagulatory potency and provocation of adverse effects are linked to different subfractions of heparin. A heparin subfraction of 4000 to 6000 Daltons rather specifically inhibits factor Xa and therefore has a very high antithrombotic potency. Its effects on release of lipases are minor. During a four year period five patients on maintenance hemodialysis were treated with this low molecular weight heparin (LMWH) subfraction. Additionally, another five patients successively received standard heparin, LMWH and again standard heparin. At all circumstances during treatment with LMWH there was a significant (0.001 less than P less than 0.05) reduction both of cholesterol and triglyceride blood concentrations. LMWH is efficient in avoiding clotting in extracorporeal circuit during hemodialysis in doses of 17 to 95 U/kg (initial dose) and 7 to 20 U/kg/hr (continuous dose).

Aged↗
PubMed1991

[Peritoneal deciduosis: cause for mechanical ileus in pregnancy].

Decidual transformation of the peritoneum is a frequent occurrence during pregnancy. Incidence and pathogenesis are vague. Complications like bleeding, suspicion of cancer and adhesions are rare. We present a case of mechanical ileus, followed by acute prerenal failure of the kidney caused by decidual transformation of the peritoneum.

Adult↗
PubMed1991

Theoretical approach and clinical application of kinetic modelling in dialysis.

Using kinetic modelling for shaping profile dialysis, we present a promising approach to improve the cardiovascular stability of patients during dialysis treatment. In order to obtain an insight into the physiological mechanisms of increased stability, a model considering alterations of electrolytes and water distribution and of acid-base status was developed. This algorithm was used for the evaluation of 114 dialysis sessions, which were performed with highly individualised profiles. Each profile was developed for one patient by trying empirically to prevent episodes of hypotension as well as other clinical problems throughout dialysis. The main advantage of profile dialysis compared to standard bicarbonate dialysis, for example, is a reduced water influx into the cell during the treatment. According to our clinical and theoretical results a correlation between water influx into the cell and time of occurrence of hypotensive episodes in individuals can be assumed. Hypotension usually starts after 0.5 litres of water have entered the intracellular space, regardless of the time necessary for this fluid shift.

Acid-Base Equilibrium↗
PubMed1991

Bacterial nutrients in drinking water.

Regrowth of coliform bacteria in distribution systems has been a problem for a number of water utilities. Efforts to solve the regrowth problem have not been totally successful. The current project, which was conducted at the New Jersey American Water Co.-Swimming River Treatment Plant, showed that the occurrence of coliform bacteria in the distribution system could be associated with rainfall, water temperatures greater than 15 degrees C, total organic carbon levels greater than 2.4 mg/liter, and assimilable organic carbon levels greater than 50 micrograms of acetate carbon equivalents per liter. A multiple linear regression model based on free chlorine residuals present in dead-end sections of the distribution system and temperature predicted 83.8% of the heterotrophic plate count bacterial variation. To limit the growth of coliform bacteria in drinking water, the study concludes that assimilable organic carbon levels should be reduced to less than 50 micrograms/liter.

Carbon↗
PubMed1991

[Determination of duration of action of beta blockers with Holter-ECG registration].

Duration of Action of Betaadrenergic Blockers Determined with Holter-ECG in Healthy Volunteers In phase I, the duration of action of betaadrenergic blockers is usually determined from the reduction of exercise induced tachycardia. In this randomized placebocontrolled doubleblind trial, however, ambulatory 24-h heart rate monitoring was used in 12 healthy volunteers to evaluate the duration of action of the new cardioselective and vasodilating betaadrenergic blocker ridazolol (CAS413). After the control periods as well as after prospectively defined hours the following mean values of heart rate were obtained: Ridazolol: Control 65.2, 12 h 69.6, 16 h 64.9, 24 h 74.0 beasts/min, placebo: Control 64.8, 12 h 78.5, 16 h 69.7, 24 h 73.5 beats/min. Differences after 12 h were statistically significant and would have been significant after 16 h with more volunteers. Additional explorative analysis with adjustment of significance levels for multiple analysis resulted in significant effects from 2 to 14 h. It was not useful, however, to calculate the time of maximal and half-maximal effects because of the large individual variation. Holter-monitoring of spontaneous heart rate in volunteers provides a rapid orientation on the duration of action of betaadrenergic blockers. The method allows to fix prospectively reasonable times of evaluation in efficacy trials in patients with coronary artery disease.

Adrenergic beta-Antagonists↗
PubMed1991

[The diagnostic value of conventional x-ray diagnosis and quantitative mineral measurements in patients with clinical symptoms of osteoporosis].

The problem of differentiating between patients suffering from osteoporosis and those with healthy bones is discussed on the basis of distribution of the age-specific and sex-specific mineral salt values in a healthy population and in a population with clinically manifest osteoporosis. By comparing the results of quantitative mineralometry and conventional x-ray films of the human skeleton in a histologically clarified group of persons with clinically manifest osteoporosis signs and symptoms, the diagnostic ranking of both methods is assessed and discussed.

Bone Density↗
PubMed1990

Leukemic transformation in polycythemia vera: analysis of risk factors.

Forty-eight patients with polycythemia vera (PV) were retrospectively studied for incidence of acute leukemia over a 12 year period. Initial clinical features, hemogram, RBC mass, B12 levels, neutrophil alkaline phosphatase (NAP), and therapy given were studied for association with development of acute leukemia. There were 25 males and mean age at diagnosis was 61.4 years. Initial Hg was 18.38 +/- 1.86 g/dl, WBC 16.44 +/- 12.92 (x 1,000/mm3), platelets 632.94 +/- 303.81 (x 1,000/mm3), B12 1,030.93 +/- 445.20 pg/ml, and neutrophil alkaline phosphatase (NAP) score 136.63 +/- 55.14. Twenty-three patients were treated with phlebotomy alone and 25 received additional myelosuppressive therapy as follows--2 received p32 alone, 4 alkylating agents alone, 8 hydroxyurea (HU) alone, and 11 received 2 or more (multiple) of these agents. None of those treated with phlebotomy alone but 6 of 25 (24%) patients given myelosuppressive therapy developed acute leukemia (P = .03) after a mean period of 46.8 months from start of myelosuppressive therapy. Four of the 11 patients (36%) receiving multiple agent therapy developed acute leukemia (P = .019). Initial hemoglobin levels, but not the other clinical parameters, were significantly higher in patients who developed acute leukemia (P = .002), and this difference persisted in various subgroups receiving myelosuppressive therapy. Thus, high initial hemoglobin and use of any myelosuppressive therapy are associated with an increased risk of leukemic transformation in polycythemia vera. This risk becomes substantial with the use of two or more myelosuppressive agents. Since myelosuppressive therapy does not prolong survival, its role in the management of polycythemia vera should be reexamined.

Acute Disease↗
PubMed1990

Heterozygous expression of X-linked chondrodysplasia punctata. Complex chromosome aberration including deletion of MIC2 and STS.

Two females showing partial expression of X-linked chondrodysplasia punctata were identified in a family. Bone dysplasia was caused by an aberrant X chromosome that had an inverse duplication of the segment Xp21.2-Xp22.2 and a deletion of Xp22.3-Xpter. To characterise the aberrant X chromosome, dosage blots were performed on genomic DNA from a carrier using a number of X-linked probes. Anonymous sequences from Xp21.2-Xp22.2 to which probes D2, 99.61, C7, pERT87-15, and 754 bind were duplicated on the aberrant X chromosome. The proposita was heterozygous for all these markers. Dosage blots also showed that the loci for steroid sulfatase and the cell surface antigen 12E7 (MIC2) were deleted as expected from the cytogenetic results. Mouse human cell hybrids were constructed that retained the normal X in the active state. Analysis of these hybrid clones for the markers from Xp21.2-Xp22.2 revealed that all the alleles of the informative markers, present in a single dosage in the genomic DNA, were carried on the normal X chromosome of the proposita. The duplicated X chromosome therefore had two identical alleles, indicating that the aberration resulted from an intrachromosomal rearrangement.

Adult↗
PubMed1990

[Eccentric coronary stenoses--definition and incidence in coronary angiograms].

The frequency of "eccentric" stenoses was determined in 676 coronary angiograms, which proved to be useful to classify stenoses according to their position (central, eccentric), as well as to the form of residual lumen (round, not round). The results for 616 stenoses which could be evaluated for both position and form were: 30% (183/616) centrally located with round residual lumen; 10% (60/616) centrally located with no round residual lumen; 41% (255/616) eccentrically located with round residual lumen; 19% (115/616) eccentrically located with no round residual lumen. These results are in agreement with previous autopsy findings. The location and form of coronary stenoses may have different meanings: the prevalent round form of residual lumina (71% of all evaluated stenoses) may characterize a normal growing of stenoses, while no round forms might indicate complications such as ruptures with hemorrhage within plaques. The prevalent eccentric location of residual lumina (63% of all evaluated stenoses) may reflect a tendency to dynamic coronary tone within the respective coronary stenosis. This assumption is supported by similar frequencies of dilatative or constrictive responses in patients with coronary artery disease. Individual prognoses, however, with respect to coronary tone or coronary reactions cannot be predicted from morphology.

Coronary Angiography↗
PubMed1989

Expression in Escherichia coli of catalytically active phenylalanine ammonia-lyase from parsley.

In parsley (Petroselinum crispum), phenylalanine ammonia-lyase (PAL) is encoded by 4 structurally similar genes. The nucleotide sequence of a near full-length cDNA and the deduced amino acid sequence of PAL-4 are presented and compared with the corresponding sequences of PAL-1, a previously described representative of the gene family. Transformation of Escherichia coli cells with PAL-1 or PAL-4 cDNA yielded catalytically active PAL, suggesting that the catalytic center of the enzyme is formed spontaneously rather than by a plant-specific mechanism.

Ammonia-Lyases↗
PubMed1989

POEMS syndrome associated with polycythemia vera.

POEMS syndrome is a multisystem disorder associated with polyneuropathy, organomegaly, endocrinopathy, a monoclonal protein (M-protein), and skin changes. The authors describe a patient with POEMS syndrome who has polyneuropathy of the upper and lower extremities, splenomegaly, impotence, IgA-lambda monoclonal protein (M-protein), and marked thickening of his skin. In addition, he has polycythemia vera. Although myeloproliferative disorders have been reported to occur in association with multiple myeloma, they have not been described with POEMS syndrome. The possible etiology of this association is discussed. This patient was successfully treated with melphalan and prednisone at the time of his initial diagnosis, but relapsed 10 years later. The relapse was treated with pulse doses of prednisone alone with complete resolution of his polyneuropathy and skin changes. This was accompanied by a fall in his IgA levels and improvement of his polycythemia.

Adult↗
PubMed1989

Renal epithelial cell lines (BSC-1, MDCK, LLC-PK1) express 11 beta-hydroxysteroid dehydrogenase activity.

Renal tissue of several species has been shown to express considerable 11 beta-hydroxysteroid dehydrogenase (11-HSD, EC 1.1.1.146) activity. However, it is uncertain as to which renal cell types exhibit 11-HSD activity. In the present study, we investigated corticosterone metabolism in BSC-1 cells, a continuous renal epithelial cell line derived from the African green monkey (Cercopithecus aethiops). In incubation experiments using 3H-labelled corticosterone and HPLC, we have demonstrated oxidative 11-HSD activity in intact monolayers of BSC-1 cells as well as in BSC-1 cell homogenates. 11-HSD activity in cell homogenates could be stimulated 7-9-fold by the addition of exogenous NADP+ (1 mM). In contrast, no reductive 11-HSD could be detected either in intact cells or in cell homogenates under various experimental conditions which were designed to favor reductive 11-HSD activity. Pilot experiments were performed in cell homogenates from two other renal epithelial cell lines derived from canine (MDCK) and porcine (LLC-PK1) kidney. They also revealed oxidative but no reductive 11-HSD activity. The data provide evidence for an epithelial localization of renal oxidative 11-HSD activity.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1989

[Cor triatriatum in adulthood].

Cor triatriatum was diagnosed in a 32-year-old woman (Case 1) and a 36-year-old man (Case 2). The definitive diagnosis in Case 1 was made by transthoracic 2-D echocardiography, in Case 2 (after a chance finding) only after additional transoesophageal echocardiography. Colour Doppler echo in Case 1 provided information on the number and localization of membrane openings, while in Case 2 simultaneous measurement of maximal flow velocity and normal right-sided pressures indicated that the anomaly was haemodynamically insignificant owing to the size of the central opening in the membrane (maximal diameter 2.1 cm). In Case 1, abnormal haemodynamic findings on right-heart catheterization provided the indication for surgery and the membrane was successfully removed. Postoperatively the patient was much improved and cardiac catheterization demonstrated normal values.

Adult↗