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Biomedical subjects

M Schmidt

Publications and source records attributed to M Schmidt.

At least 1,081 records · Page 60Linked to original sources
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[Homologous blood use and possibilities for autologous hemotherapy as exemplified in hip and knee endoprostheses].

In a retrospective study we documented the need for blood transfusion in total knee (TKR) and hip replacement (THR). The problems with homologous blood transfusion in orthopedic surgery and alternative techniques of autologous-blood transfusions are discussed. In this series patients with primary THR needed 1.69 (+/- 2.25) blood units, with primary TKR 1.58 (+/- 1.54) blood units, and secondary TKR 1.19 (+/- 1.47) blood units, Secondary THR required significantly more units (3.85 +/- 3.07). These procedures also asked for significantly more plasma (3.27 +/- 3.95) than all other procedures. For secondary THR 2.63 (+/- 2.45) blood units were intraoperatively used and only 1.23 (+/- 1.09) blood units postoperatively. All other procedures needed postoperatively significant more units than intraoperatively. In secondary THR the use of blood transfusions increased with age. 45% of the patients with primary THR and 15% with secondary THR were operated without additional blood transfusion. In secondary THR 36% of all patients needed more than 4 blood units and 27% more than 4 plasma units. In TKR 39% of the primary cases and 50% of the secondary cases were operated on without additional homologous blood. Based on these results we established a transfusion concept for our department. Economic, practical, as well as legal aspects were taken into account.

Adult↗
PubMedDate not supplied

[Treatment of varus gonarthrosis using Coventry's modified technic].

A high plane femoral head osteotomy technique after Coventry, modified by Blauth, is described; during the last 10 years it has been used in over 200 cases at Kiel University Orthopedic Clinic. In the present paper the mid-term findings in follow-ups of 100 osteotomies in 86 patients are analyzed. Of these interventions, 83% resulted in a significant reduction in complaints at rest and on loadbearing, a considerable improvement in walking ability, and clinically a strengthening of the ligamentous apparatus as well as a reduction in irritation. The 17% poor results were mainly patients with advanced panarthroses, knee-bending contractures and increased loosening of the ligaments. In almost all of these cases, the axial error was insufficiently corrected, while the good results were usually associated with over-correction. In cases of varus gonarthrosis we therefore aim for 5 degrees overcorrection. With the exception of a motoric paresis of the peroneal nerve and a deep infection which healed without sequelae, there were no serious complications. This method can thus be recommended as a reliable procedure.

Arthritis↗
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Changes in sexual function during acute and six-month fluoxetine therapy: a prospective assessment.

Sexual dysfunction has been reported as an unwanted effect associated with selective serotonin reuptake inhibitors therapy, but the nature and frequency of such effects have not been characterized systematically. Sexual function was assessed in depressed patients participating in a multicenter trial of acute and continuation fluoxetine therapy using a 4-item self-rated scale. Patients were evaluated at study entry, after 13 weeks of fluoxetine 20 mg daily, and during 25 weeks of continuation therapy with fluoxetine 20 mg daily, fluoxetine 90 mg weekly, or placebo. In a 13-week open-label trial, among 501 patients who met Diagnostic and Statistical Manual of Mental Disorders criteria for depression, 51.6% of women and 40.6% of men reported improvement, 35.0% of women and 41.9% of men reported no change, and 13.4% of women and 17.4% of men reported worsening in overall sexual function. During double-blind continuation therapy, there were no statistically significant differences in change in sexual function between treatments. Worsened sexual function that occurred during continuation treatment was strongly associated with worsened depressive symptoms. Depression is associated with sexual dysfunction, and improvement in sexual functioning related to the antidepressant effects of fluoxetine may be more common than drug-associated deterioration in sexual function. Among patients who report worsening, effects may be most pronounced on orgasm. Deterioration in sexual function does not appear to be a late-onset drug-specific event, but is strongly related to worsening depressive symptoms.

Adult↗
PubMedDate not supplied

Monoclonal antibodies against human endothelin-converting enzyme-1.

Endothelin-converting enzyme-1 (ECE-1) is a membrane-bound metalloprotease which specifically converts the inactive precursor big-endothelin-1 (big ET-1) to the vasoactive endothelin-1 (ET-1). Six different mouse hybridoma cell lines have been generated secreting monoclonal antibodies specific to human ECE-1. These antibodies have been proven useful in a fast and efficient one-step purification of membrane-bound ECE-1 as well as of artificial soluble ECE-1 by immunoaffinity chromatography. The antibodies are suitable for a quantification of ECE-1 in solution by a sandwich-ELISA and for the immunohistochemical detection of ECE-1 in the cell membrane.

Animals↗
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Molecular analysis of the Rhizobium meliloti mucR gene regulating the biosynthesis of the exopolysaccharides succinoglycan and galactoglucan.

The Rhizobium meliloti Tn5 mutant Rm3131, producing galactoglucan (EPS II) instead of succinoglycan (EPS I), was complemented by a 3.6-kb EcoRI-fragment of the Rhizobium meliloti genome. Sequencing of this fragment revealed six open reading frames (ORFs). The ORF found to be affected in the mutant Rm3131 codes for a putative protein of 15.7 kDa and forms a monocistronic transcriptional unit. Further genetic analysis revealed that the gene mutated in Rm3131 is identical to the previously described R. meliloti mucR gene (H. Zhan, S.B. Levery, C. C. Lee, and J.A. Leigh, 1989, Proc. Natl. Acad. Sci. USA 86:3055-3059). By hybridization it was shown that a mucR homologous gene is present in several rhizobacteria. The deduced amino acid sequence of MucR showed nearly 80% identity to the Agrobacterium tumefaciens Ros protein, a negative regulator of vir genes and necessary for succinoglycan production. MucR contains like Ros a putative zinc finger sequence of the C2H2 type. Transcriptional fusions of genes for EPS I and EPS II synthesis, the so-called exo and exp genes, with the marker gene lacZ were used to delineate the role of mucR for exo and exp gene expression. It was found that exp genes are negatively regulated by MucR on the transcriptional level, whereas a posttranscriptional regulation by MucR is assumed for exo genes. Furthermore, mucR is negatively regulating its own transcription.

Amino Acid Sequence↗
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Pharmacological characterization of renal vascular dopamine receptors.

We present an in vitro method for studying the renal effects of dopamine in the isolated rat kidney. The organ is perfused in an open circuit and can be maintained satisfactorily for up to 180 min. The responses to dopamine were studied in the presence of phenoxybenzamine (10(-5) M) and sotalol (10(-5) M) while stable renal vasoconstriction was maintained by perfusion with prostaglandine F2 alpha. Dopamine induced dose-dependent renal vasodilation with an ED50 of 2.53 X 10(-6) moles/liter, which was not modified by reserpine pretreatment. (+) Butaclamol but not (-) butaclamol shifted the dopamine dose-response curve to the right in a parallel fashion, indicating competitive antagonism. Haloperidol and sulpiride at concentrations without intrinsic effect on vascular resistance also acted as competitive inhibitors for dopamine. Calculation of empirical pA2 values yielded the following relative potencies for these antagonists: (+) butaclamol greater than haloperidol greater than sulpiride. The renal vascular dopamine receptors are tentatively classified as being of the D1 type.

Animals↗
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Blockade of dopamine receptors in the renal vasculature by isomers of flupenthixol and sulpiride.

We studied the renal vascular effects of flupenthixol and sulpiride isomers in the isolated perfused rat kidney in the presence of phenoxybenzamine (10(-5) M) and sotalol (10(-5) M). The vascular bed was contracted with prostaglandin F2 alpha (10(-7) -3 X 10(-6) M) and dose-dependently relaxed with dopamine. Cis-flupenthixol (10(-9)-10(-7) M) antagonized competitively the response to dopamine (apparent pA2 = 8.34 +/- 0.09; mean +/- SD) without affecting papaverine-induced relaxation. Trans-flupenthixol was without effect at 10(-7) M. The dopamine receptor antagonist activities of the sulpiride isomers are low and d-sulpiride is twice as active as 1-sulpiride. Thus, the renal vascular dopamine receptor can be further characterized by the relative antagonist activities of cis-flupenthixol and sulpiride and by a rather low stereospecificity in favor of d-sulpiride.

Animals↗
PubMedDate not supplied

Postprocessing techniques for gadolinium-enhanced three-dimensional MR angiography.

Contrast material-enhanced three-dimensional (3D) magnetic resonance (MR) angiography is rapidly gaining acceptance as a versatile noninvasive alternative to conventional angiography. The technique has proved useful in the visualization and assessment of complex pathologic entities in the thoracic and abdominal aorta, renal arteries, pelvic arterial system, and pulmonary arteries. Several postprocessing techniques are available for reformation of the imaging data, including maximum intensity projection (MIP), surface rendering, and virtual intraluminal endoscopy (VIE). MIP and subvolume MIP reconstructions can be produced quickly and are useful for demonstration and archiving purposes. Because of its unique ability to display vessels without overlap, surface rendering is especially useful in depicting diseases that influence either the outer shape of the vessels or their topographic arrangement. VIE allows assessment of the inside of the vascular wall and is helpful in detecting wall-bound thrombus and evaluating the degree of stenosis. Most clinically relevant questions (eg, presence of pulmonary embolism, aortic aneurysm, renal artery stenosis) can be fully answered if analysis is based on MIP and thin multiplanar reformations of contrast-enhanced 3D MR angiograms. In some cases, the use of additional postprocessing techniques enhances diagnostic confidence.

Aorta↗
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Marine biosurfactants, I. Screening for biosurfactants among crude oil degrading marine microorganisms from the North Sea.

Three bacterial strains of marine origin were isolated during a screening for biosurfactants among n-alkane degrading microorganisms. One strain-identified as Alcaligenes sp. MM1-produced a novel glucose lipid. In the case of Arthrobacter sp. EK 1 the well-known trehalose tetraester was found as major component. From another pure culture classified as Arthrobacter sp. SI 1, extracellular emulsifying agents with properties indicating high molecular weight substances were detected. Furthermore trehalose corynomycolates were found at up to 2 g/l. The isolated biosurfactants showed good interfacial and emulsifying properties.

Alcaligenes↗
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MRI assessment of coronary artery disease.

With the application of magnetic resonance imaging (MRI) in clinical cardiology, important tools have been added to the currently available techniques for the evaluation of coronary artery disease (CAD). Technical advantages of MRI in comparison to established imaging techniques are the excellent spatial resolution, the characterization of myocardial tissue and the potential to acquire a three dimensional set of data. This allows the accurate assessment of left ventricular mass and volume and the determination of systolic wall thickening and wall motion abnormalities. Myocardial perfusion, metabolism and inducible myocardial ischemia with the use of pharmacological stress also can be assessed by MRI. Future technical improvements in real-time imaging and development of non-invasive visualization of the coronary arteries and coronary artery bypasses will constitute a considerable progress in clinical cardiology. A particular strength of MRI is the potential to encompass cardiac anatomy, function, perfusion, metabolism and coronary angiography in a single study. The replacement of multiple diagnostic tests with a single MR study allowing to assess different aspects of CAD may have a major impact on cardiovascular health care economics.

Cardiac Volume↗
PubMedDate not supplied

Involvement of p21Waf1 in mediating inhibition of paclitaxel-induced apoptosis by epidermal growth factor in MDA-MB-468 human breast cancer cells.

Paclitaxel (Taxol) is currently one of the most widely used anti-cancer drugs for human breast cancer. In this study, we investigated how epidermal growth factor (EGF) modulated paclitaxel-induced apoptosis in MDA-MB-468 human breast adenocarcinoma cells. Pulse-exposure of the cells to paclitaxel resulted in cell death through apoptosis. When EGF was present during the post-paclitaxel culture period, this paclitaxel-induced apoptosis was inhibited in an EGF dose-dependent manner. The induction of apoptosis by paclitaxel was accompanied by an elevated level of p34cdc2 kinase activity, which was inhibited in the presence of EGF during the post-paclitaxel culture period. Exposure of MDA-MB-468 cells to EGF induced expression of the cyclin-dependent kinase inhibitor p21Waf1. Incubation of paclitaxel-treated MDA-MB-468 cell extracts with EGF-treated MDA-MB-468 cell extract, which exhibited elevation of p34cdc2 activity, inhibited the kinase activity. This inhibition was not observed with p21Waf1-immunodepleted EGF-treated cell extract. Transfection of the cells with p21Waf1 antisense oligonucleotide abolished the induction of p21Waf1 and also significantly reduced inhibition by EGF of paclitaxel-induced apoptosis. These studies demonstrate that p21Waf1 plays a key role in the inhibition of paclitaxel-induced apoptosis by EGF in MDA-MB-468 cells.

Adenocarcinoma↗
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Marginal quality of tooth-colored restorations in class II cavities after artificial aging.

This in vitro study compared the proximal marginal adaptation of direct composite restorations with composite and ceramic inlays inserted with different resin cements. Standardized MOD Class II inlay cavities with one proximal box extending below and the other above the CEJ were cut in 48 extracted human molars and randomly assigned to six groups (n=8). Incrementally layered direct composite restorations (P60), composite inlays (P60) and ceramic inlays (Empress; Cerec Vitablocs Mark II) were placed in the cavities. Three different resin cements (RelyX ARC; Variolink II high viscosity; Panavia 21) were used for luting the composite inlays. All ceramic inlays were cemented with RelyX ARC. After finishing and polishing, the teeth were stored for 24 hours in Ringer solution at 37 degrees C before they were subjected to thermal and mechanical loading (5/55 degrees C, 2000x; 50 N vertical load, 50000x). Margins were evaluated on epoxy replicas using a scanning electron microscope at X200 magnification. Statistical analysis was performed with non-parametric test methods (alpha=0.05). The adhesive interfaces to enamel exhibited high percentages of perfect margins for all groups (91.8% to 96%) and a maximum of 5.2% marginal gap formation. Dentin-limited cavity segments demonstrated more marginal openings and less perfect margins than enamel-bound areas; however, this was only statistically significant for direct composite restorations and composite inlays inserted with Variolink II and Panavia 21. RelyXARC showed a significantly better adaptation to P60 inlays compared with the leucite-reinforced Empress ceramic but not the Vitablocs Mark II ceramic.

Aluminum Silicates↗
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[Not Available].

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Expeditions↗
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Reversible MRI changes in a patient with uremic encephalopathy.

A 19-year-old patient on chronic ambulatory peritoneal dialysis experienced severe neurologic disturbances caused by uremia. Increased signal intensity was seen bilaterally in the cortical and subcortical areas of the occipital and parietal lobe on cranial magnetic resonance imaging (MRI). Insufficient peritoneal dialysis efficacy was documented and the patient was switched from peritoneal to hemodialysis. Cranial MRI indicated a marked regression of the lesions to nearly normal, confirming the diagnosis of uremic encephalopathy.

Adult↗
PubMedDate not supplied

[HLA antigens in cleft lip-palate patients].

HLA typing of 50 patients with cleft lip and/or cleft palate (50 HLA-ABC and 35 HLA-DR tests) and, in part, also of their families showed an increased frequency of the antigens HLA-AII, DRw6 and the haplotype HLA-A11, B35 as against the normal population. Disorders of wound healing were observed more frequently in patients with HLA antigens A11 and B15 than in those without these antigens. Based on these hints of an HLA association (p values after correction are not significant), and the frequent coincidence of HLA-DR antigen in the patients' parents, as well as the increased rate of HLA-DR homozygosity of the patients, it is assumed that genetic factors of the HLA complex or an HLA-linked complex play a part in the etiology of clefts of the lip and cleft palate.

Adolescent↗