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Biomedical subjects

U Maurer

Publications and source records attributed to U Maurer.

At least 55 records · Page 3Linked to original sources
PubMed1996

Activation of the clotting system during extracorporeal membrane oxygenation in term newborn infants.

OBJECTIVES: To determine the degree of clotting activation that occurs with the usual anticoagulation regimen with systemic heparinization. METHODS: To allow a standardized comparison of the patients, this study focused on the first 48 hours of extracorporeal membrane oxygenation (ECMO) in term newborn infants. The ECMO perfusion circuit consisted of a roller pump, silicone membrane lungs, and silicone rubber tubing. Coagulation was controlled routinely by measuring prothrombin time, fibrinogen, antithrombin III, and reptilase time. Platelet counts, activated clotting time, and heparin concentration were controlled regularly. The following specific activation markers of the clotting system were measured: prothrombin activation fragment 1 + 2(F1+2), thrombin-antithrombin III complexes, and D-dimer. Measurements were done before the start of ECMO, after 5 minutes, and at hours 1, 2, 3, 4, 6, 12, 24 and 48. RESULTS: All seven term infants had excessively high levels of clotting activation markers within the first 2 hours of ECMO: F1+2, 11.6(+/- O.9) nmol/L (mean +/- SEM); thrombin-antithrombin, 920(+/- 2.2) microg/L; D-dimer, 15.522(+/- 3.689) ng/L. During the next 46 hours of ECMO, F1+2 and thrombin-antithrombin III complexes decreased from those high values, whereas D-dimer did not. The increase of activation markers was accompanied by low fibrinogen, low platelet counts. and prolongation of reptilase time. CONCLUSIONS: These findings fit the pattern of consumptive coagulopathy during neonatal ECMO, especially in the first 24 hours.

Anticoagulants↗
PubMed1996

[5-fluorouracil: cause of a fatal myocardial infarction in combined radiochemotherapy?].

PURPOSE: A 53-year-old female patient was treated with combined radiochemotherapy with 5-fluorouracil (5-FU) because of adenocarcinoma of the lung. She died after the 2nd day of the first course on fatal myocardial infarction. The histological evaluation of the heart revealed no severe chronic fibrosis. In our opinion the myocardial infarction was partly 5-fluorouracil-related in this case. PATIENTS AND METHODS: Published case reports on this theme were reviewed and discussed. RESULTS: The review of the literature showed a 5-FU associated cardiotoxicity in 98 cases. Most of the patients were without evidence of pre-existing myocardial disorders. The discussion about the reasons of the 5-FU-associated cardiotoxicity is still going on. Cardiotoxicity will rise up in 1.1% to 4.5% of the patients treated with 5-FU. Patients with a history of cardiac disease were at significantly increased risk for 5-FU-induced cardiotoxicity. CONCLUSION: In high-risk-patients 5-FU should not be given without electrocardiographic monitoring. The continuous infusion is better than a bolus treatment.

Adenocarcinoma↗
PubMed1996

[Radiotherapy in advanced osseous destruction in chronic myeloid leukemia. A case report].

PURPOSE: Chronic myelocytic leukemia is a disease of myeloproliferative disorder. In chronic myelocytic leukemia occasionally myelosarcomas occur as defined tumors which can cause localized symptoms. We report a case of successful palliative radiotherapy. PATIENT AND METHODS: A 44-year-old patient with total destruction of the left humerus caused by myelosarcoma of the bone in chronic myelocytic leukemia was treated with percutaneous megavoltage radiotherapy, the total applied dose was 40 Gy. After radiotherapy the patient was free of pain. The tumorous swelling of soft tissue subsided completely, there was total formation of callus in the affected humerus and the patient could be mobilized. CONCLUSIONS: This case report confirms the high effectiveness of palliative radiotherapy even in advanced cases of myelosarcomas which has been described in literature.

Adult↗
PubMed1995

Sonographically guided cannula positioning for extracorporeal membrane oxygenation.

Drainage problems due to catheter malpositioning are acutely life-threatening in patients undergoing extracorporeal membrane oxygenation. In order to reduce these complications we introduced sonographically guided catheter positioning. We compare the outcome in a group of patients with blind cannula positioning to that in a group with sonographically guided catheter positioning. Our results show that neonates and young infants especially are at high risk of drainage problems due to catheter malposition and that their outcome could be markedly improved by introducing sonographically guided cannula insertion.

Catheterization↗
PubMed1995

The Wilms' tumor gene is frequently expressed in acute myeloblastic leukemias and may provide a marker for residual blast cells detectable by PCR.

BACKGROUND: The tumor suppressor gene wt-1 was isolated by cytogenetic deletion analysis of patients with Wilms' tumor (wt-1). This gene encodes for a zinc finger DNA-binding protein with transcription-repressing properties. During normal ontogenesis it is expressed in a time- and tissue-dependent manner mainly in the kidneys and gonads. Recently, the expression of wt-1 in acute leukemias (AL) was reported. Here we investigated the prognostic potential of wt-1 mRNA expression during the course of the disease using the PCR technique. PATIENTS AND METHODS: Blast cells from 83 patients with newly diagnosed AML and 20 AML patients during follow-up in complete remission were analyzed for wt-1 mRNA expression. Peripheral blood mononuclear cells (PBMNC) and bone marrow (BM) from healthy persons (n = 13) and sorted CD34-positive cells from normal donors (n = 4) were used as negative controls. RESULTS: Wt-1-specific m-RNA was detectable in 67/83 (81%) patients with AML. Normal donors did not express wt-1 m-RNA but in 1/4 sorted CD34+ cell samples a weak amplified product was observed. After achieving cytological CR 14/20 studied patients lost wt-1 expression. In 7/8 patients in morphological CR the reappearance of wt-1 expression preceded relapse of the disease, in 1/8 patients wt-1 remained positive in CR. Response to therapy, disease-free survival, overall survival and FAB-subtype did not correlate with wt-1 m-RNA expression in newly diagnosed AML before therapy. CONCLUSIONS: In the majority of acute leukemias wt-1 is expressed and probably blast cell-associated, at least in levels detectable by PCR. Wt-1 mRNA was detectable in bone marrow cells of AML patients in clinical CR. The results strongly suggest that the persistence or reappearance of wt-1 predicts relapse of the disease prior to morphological relapse.

Adult↗
PubMed1995

[Extracorporeal membrane oxygenation in newborn infants and children].

The purpose of this report is to describe our experience with veno-arterial (VA) and veno-venous extracorporeal membrane oxygenation (VV-ECMO) for neonates and children with severe acute respiratory or cardiocirculatory failure. From 1990 to 1994 20 neonates and 12 children were treated at the ECMO center in Graz. Indications for ECMO were acute respiratory failure in 27 patients and cardiocirculatory failure in 5 patients. Mean duration of ECMO was 228 +/- 30 hours. Fifteen neonates were weaned from ECMO and were subsequently extubated. Of the 12 children 7 had severe acute respiratory failure and underwent VV-ECMO. Five of these 7 children were weaned from ECMO and subsequently extubated. Only two of 5 patients with cardiac ECMO support could be weaned from bypass; one patient subsequently died, but the other patient is a long-term survivor. All patients with cardiac ECMO support after open heart surgery had severe mediastinal bleeding. The survival rate in neonates and pediatric patients with respiratory failure treated by ECMO was 75% and 71%, respectively, whereas it was only 20% in children with cardiocirculatory failure. Major complications on ECMO were local and intracerebral bleeding. ECMO is an effective therapy for neonates and children with acute respiratory failure. It is less effective for cardiac support in children after open heart surgery, but the use of heparin-layered ECMO systems might increase the safety of the procedure.

Carbon Dioxide↗
PubMed1994

Different distributions of glycosphingolipids in mouse and rabbit skeletal muscle demonstrated by biochemical and immunohistological analyses.

The expression of neutral glycosphingolipids and gangliosides was investigated in mouse and rabbit skeletal muscle by means of biochemical and immunochemical techniques. Neutral glycosphingolipids from muscle of the inbred rabbit strain used in this study showed a simple TLC pattern, comprising mainly monohexosylceramide. In addition to this compound, lactosylceramide, lacto-N-neotetraosylceramide, globoside and Forssman GSL were detected in mouse muscle. The major ganglioside in both species was GM3; GM3 (Neu5Ac) and GM3(Neu5Gc) were found in a 3:1 ratio in mouse muscle, whereas the absence of GM3(Neu5Gc) is characteristic of rabbit muscle. As a general structural feature of all muscle GM3 gangliosides investigated, a C18 fatty acid and C18 sphingosine were the major components besides minor C22 and C24:1 fatty acids of the respective ceramide portions, as revealed by positive and negative ion FAB-MS. alpha 2-3 sialylated lacto-N-neotetraosyl-ceramide (sialylparagloboside) was expressed in both species, whereas the alpha 2-6 sialylated isomeric compound was found only in mouse muscle. Minute quantities of ganglio-series GM1, GD1a, GD1b, and GT1b were detected in muscles from both species. Glycosphingolipid expression could be confirmed immunohistochemically by examining transverse and longitudinal cryosections of skeletal muscle samples. The results provide the basis for the investigation of muscle specific glycosphingolipids that might modulate membrane protein functions in muscle.

Animals↗
PubMed1993

Scintigraphy and sonography in reflux nephropathy: a comparison.

The evaluation of reflux nephropathy (RNP) is a major task in the following up of children with vesicoureteral reflux (VUR). Adequate monitoring of RNP development depends on the frequent use of sonographical and scintigraphical examinations. In order to evaluate the accuracy of sonography in monitoring RNP 63 patients suffering from VUR (mean age: 8.8 years, range: newborn to 18 years, male:female = 19:44) were examined prospectively. We calculated renal size sonographically and compared our data to static and dynamic renographic findings. Our results showed a good correlation between relative DMSA uptake and sonographically estimated relative renal size (r = 0.95, P < 0.001), whereas not unexpectedly the correlation between relative kidney function and sonographically estimated renal size was poor (r = 0.83, P < 0.01). We therefore believe, that in monitoring children with VUR, sonography can offer accurate information on questions about renal size and renal parenchymal structure as well as pelvic distention. With very small kidneys as well as with kidneys showing severe dilatation and above all for evaluating renal function, scintigraphy proved to be the better method.

Adolescent↗
PubMed1993

[Artificial respiration of premature infants].

Better understanding of respiratory physiology and progress in ventilator technology have contributed to improved mortality and morbidity of premature neonates. Yet, pulmonary complications remain high and there is no consensus about the optimal regimen of mechanical ventilation. We report our satisfactory 10-year experience with conventional mechanical ventilation based on a relatively low incidence of pulmonary barotrauma. The introduction of surfactant has facilitated the ventilatory management of premature neonates since the usually rapid improvement of the acute lung disease after surfactant administration allows for earlier weaning from mechanical ventilation. However, our own results and the results from most surfactant studies show no significant reduction in the incidence of intraventricular haemorrhage. Thus, though mechanical ventilation and surfactant administration are milestones in neonatal therapeutic management, the problems encountered in very low birth weight neonates both with respect to mortality and morbidity have not been generally solved and underline the role of optimal perinatal management.

Asphyxia Neonatorum↗
PubMed1992

The role of sonography in the evaluation of gastro-oesophageal reflux--correlation to pH-metry.

Sonography was compared to pH-metry and/or oesophagomanometry to evaluate the accuracy of sonography in the early diagnosis of gastro-oesophageal reflux. Thirty children with a mean age of 72 days (21-252 days) were studied. The results showed that specificity of sonographic diagnosis was 87.5% and sensitivity was 100% (with P less than 0.001). Sonography also proved helpful in providing both functional and morphological data in addition to pH-metric results. This study therefore suggests that sonography is useful as the first approach in the diagnosis of vomiting babies as it is non-invasive and provides sufficient diagnostic accuracy.

Female↗
PubMed1992

[The effect of high-dose peroral zidovudine treatment in a 4-year-old child with HIV encephalopathy].

We report a four-year-old boy with HIV encephalopathy after vertical HIV infection. On the first admission to our hospital he showed ataxia, loose of expressive language and interstitial pneumonia. After treatment of the pneumonia the patient was started on oral zidovudine with 6 x 6 mg/kg bw/day, because of persisting neurologic symptoms and deep white matter lesions in the MR tomogram of the brain. Two months later he showed an improvement of the gait and the reappearance of the expressive language. Seven months after the start with zidovudine the MR tomogram of the brain revealed the disappearance of white matter lesions with exception of little areas of demyelinisation. No side effects of treatment were observed. The only persisting pathological clinical signs were developmental delay of about a half year and moderately hyperactive tendon reflexes of the lower extremities. Our case suggests that even oral treatment with zidovudine can have a beneficial effect on the HIV encephalopathy in infants.

AIDS Dementia Complex↗
PubMed1990

Sequence of DNA replication in Macaca fuscata chromosomes: an outgroup for phylogenetic comparison between man and apes.

The relative replication times of every band in the standardized 300 band G-band idiogram of the chromosomes of the Japanese macaque are presented, and compared to the human sequence. Many chromosomes thought to be homologous between Macaca fuscata and man on the basis of standard chromosome banding and gene mapping show a conservation of the replication sequence. Other supposed chromosomal homologies between these two species show no good correspondence, and the replication sequence data suggest that these chromosomes have been subject to complex rearrangements. The replication sequence data also point to possible additional chromosomal homologies between man and M. fuscata. Asynchrony in replication time between homologues from the same cell may also be evolutionarily conserved, because these species share a number of asynchronous homologous bands. Replication band sequence data can provide significant information for comparative cytogenetics. However, usually only the full replication R- or G-band pattern has been used for interspecific comparisons. The dynamic sequence data presented here determine the replication time of every band in the karyotype, and provide a quantitatively and qualitatively more sensitive tool to characterize chromosomes. Such data could provide valuable new information on which to make phylogenetic reconstructions, and shed light on the relationship between chromosome change and evolutionary process. Finally, the M. fuscata replication sequence presented here will provide a necessary foundation for future comparisons between apes and man.

Animals↗
PubMed1989

Control of ribonucleotide reductase in heat- and cold-sensitive mammalian cell-cycle mutants.

Two heat-sensitive (reversibly arrested in G1 phase at 39.5 degrees C, multiplying at 33 degrees C) and two cold-sensitive (reversibly arrested in G1 phase at 33 degrees C, multiplying at 39.5 degrees C) cell-cycle mutants of the P-815-X2 murine mastocytoma line were tested for ribonucleotide reductase activity, using cells made permeable to nucleotides. After transfer of the heat-sensitive mutant cells to 39.5 degrees C, ribonucleotide reductase activity, similar to thymidine kinase (Schneider, E., Müller, B. and Schindler, R. (1983) Biochim. Biophys. Acta 741, 77-85), but unlike DNA polymerase alpha (Schneider, E., Müller, B. and Schindler, R. (1985) Biochim. Biophys. Acta 825, 375-383), decreased rapidly and in parallel with numbers of cells in S phase, whereas in the cold-sensitive mutant cells brought to 33 degrees C, ribonucleotide reductase activity decreased approx. 8 h later than numbers of DNA-synthesizing cells. When arrested heat- or cold-sensitive mutant cells were returned to the permissive temperature, ribonucleotide reductase activities, similar to DNA polymerase alpha and to thymidine kinase in heat-sensitive mutants, increased essentially in parallel with reentry of cells into S phase, whereas the increase in thymidine kinase activity in the cold-sensitive mutants was previously shown to occur approx. one cell-cycle time later. This indicates that ribonucleotide reductase and thymidine kinase are coordinately expressed in the heat-sensitive, but independently regulated in the cold-sensitive mutants.

Animals↗
PubMed1982

Thymidine nucleotide synthesis and catabolism by CHO cells and their changes during the cell cycle.

At 0 degrees C, CHO cells efficiently incorporated [3H]thymidine into the nucleotide fraction, but not into DNA. Upon reincubation of asynchronous cultures at 37 degrees C, 15-25% of the radioactivity contained in the cellular nucleotide fraction was released, in the form of thymidine, into the culture medium. At 0 degrees C, however, radioactivity of the nucleotide fraction was retained within the cells. Similarly, dTMP phosphatase (EC 3.1.3.35) in cell extracts was active at 37 degrees C, but not at 0 degrees C, whereas thymidine kinase (EC 2.7.1.21) was active at both temperatures. If synchronous cultures in Gl phase were prelabeled at 0 degrees C and reincubated at 37 degrees C, almost all radioactivity in the nucleotide fraction was released into the medium, whereas in S-phase cultures nearly all radioactivity of the nucleotide fraction was incorporated into DNA. In synchronous S-phase cultures treated with hydroxyurea, radioactivity in the nucleotide fraction was released into the medium at a rate considerably lower than that observed for Gl-phase cells. Rates of endogenous synthesis of thymidine nucleotides were calculated from changes of cellular thymidine nucleotide content, incorporation of thymidine nucleotides into DNA and release of thymidine into the medium during reincubation of prelabeled cultures in thymidine-free medium. The results obtained (see Table III) reveal marked differences between Gl and S phases with respect to the determinants of thymidine nucleotide metabolism.

Animals↗
PubMed1978

Determination of thymidine in serum used for cell culture media.

Thymidine concentrations in serum used for cell culture media were determined with an assay based on isotope dilution. In this assay, incorporation of (3H)-thymidine into DNA of cultured cells was measured in the presence of 5 and 20% serum as a function of the concentration of unlabeled thymidine added to the medium. In three batches of horse serum, thymidine concentrations were 0--0.17 micron, while in fetal calf serum values of 0.75--2.1 micron were obtained. Dialysis of serum resulted in a reduction of thymidine levels by factors of at least 10.

Cells, Cultured↗
PubMed1977

Comparison of ethinylestradiol and mestranol in sequential-type oral contraceptives in their effects on blood glucose and serum insulin in oral glucose tolerance tests.

Forty 3-hour oral glucose tolerance tests (OGTTs) were performed in 10 assumedly healthy female volunteers 19 to 30 years old, each serving four times as her own control. Each subject was taking a sequential type oral contraceptive containing either 50 microgram of ethinylestradiol or 80 microgram of mestranol alternatingly in four consecutive treatment cycles. The OGTTs were performed on the 6th day of each cycle, during pure estrogen medication. Blood glucose and serum insulin values did not differ significantly under either estrogen as tested by the t-test for paired observations. Our results do not support the findings of others that mestranol has a more pronounced or even exclusively adverse effect on glucose tolerance as compared with ethinylestradiol.

Adult↗