Older recipient age is associated with reduced alloreactivity and graft rejection after cardiac transplantation.
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Journal Article↗
Biomedical subjects
M Schuster
Publications and source records attributed to M Schuster.
Intravenous immunoglobulin therapy in highly sensitized cardiac allograft recipients facilitates transplantation across donor specific IGG positive cross matches.
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Journal Article↗
[NPPE - a rare anaesthetic complication].
We report a rare anaesthetic complication: NPPE (negative pressure pulmonary edema). A 20-year-old otherwise healthy man developed pulmonary edema in the early postoperative phase after uneventful general anaesthesia. The release of the edema was acute obstruction of the upper airways due to postoperative drowsiness.
Adult↗
Mitoxantrone and paclitaxel combination chemotherapy in metastatic breast cancer.
This study evaluated mitoxantrone and paclitaxel combination chemotherapy in the treatment of patients with metastatic breast cancer. Thirty-seven patients who had developed progressive disease after prior chemotherapy were treated with mitoxantrone (14 mg/m2) and paclitaxel (150 mg/m2) every 21 days for a maximum of six cycles. The most frequent grade 3 or 4 nonhematological toxicities were fever and nausea. Grade 4 neutropenia occurred in 71% of patients. Cardiotoxicity occurred in 2 patients, both of whom had previously received doxorubicin. Objective response was achieved in 35% of patients (5% complete response and 30% partial response) and 41% had stable disease. Median time to disease progression and median survival were 6 and 12 months, respectively. The percent of patients with an objective response was not different for those who had received prior doxorubicin or had chemotherapy in the preceding 6 months. This regimen appears to be effective and well tolerated as salvage therapy and merits further evaluation.
Adult↗
Persistent measles virus infection and otosclerosis.
The cause of otosclerosis is still unknown. Recently, measles virus involvement has been implicated. The aim of this study was to analyze the presence of measles virus RNA within the otosclerotic focus and to evaluate the perilymphatic antibody pattern. Bone and perilymph specimens from 40 patients with the spontaneous form of otosclerosis and from control patients were investigated by reverse transcription polymerase chain reaction (RT-PCR), Western blot techniques, and cell culture. By the use of RT-PCR, measles virus RNA could be detected in 32 patients, but not in controls. Analysis of perilymph revealed the presence of antibodies to N, F1, and M measles virus proteins in all cases, and antibodies against H protein in 2 additional cases. In preosteoblasts cultured from otosclerotic bone chips, no measles virus RNA could be amplified. We conclude that the spontaneous form of otosclerosis is, in the vast majority of cases, a measles virus-associated disease of the otic capsule.
Adult↗
Protein expression in yeast; comparison of two expression strategies regarding protein maturation.
The driving force for the modification of existing, or the development of new, protein expression systems lies in the identification of a tremendous number of potential novel drug targets through recent genomics approaches. Saccharomyces cerevisiae as a host for recombinant protein expression, offers many advantages, as its biosynthetic pathways resemble higher eukaryotic cells in many aspects. Two yeast vectors were compared to evaluate the versatility of this organism for expression of recombinant proteins. One expression vector enables the secretion of the recombinant protein into the culture medium through fusion with the leader sequence of the mating-type pheromone alpha; the other directs the expression product into the cytoplasm of the yeast cell through fusion with ubiquitin. To facilitate immunological detection and purification, proteins were expressed as fusions to an octapeptide, the so-called Flag-tag, which is recognised by a monoclonal antibody in the presence of Ca2+. We chose 20 functionally different cDNAs to compare the efficiency of both expression systems. All cDNAs could be expressed at the correct size but at varying yields and purity. Both expression systems differed greatly in the degree of glycosylation and other, not further analysed, post-translational modifications. Secretion of all model proteins into the cell culture supernatant could be accomplished if membrane domains or signal sequences were absent, but many proteins were heavily glycosylated as demonstrated by lectin mapping or enzymatical deglycosylation. Some proteins, however, were expressed as homogenous products, and could be easily purified for further functional studies. Further investigations on the expression biology of yeast are required, in order to optimise the conditions of fermentation which may finally lead to more homogeneous expression products.
Cloning, Molecular↗
Antagonism between C/EBPbeta and FOG in eosinophil lineage commitment of multipotent hematopoietic progenitors.
The commitment of multipotent cells to particular developmental pathways requires specific changes in their transcription factor complement to generate the patterns of gene expression characteristic of specialized cell types. We have studied the role of the GATA cofactor Friend of GATA (FOG) in the differentiation of avian multipotent hematopoietic progenitors. We found that multipotent cells express high levels of FOG mRNA, which were rapidly down-regulated upon their C/EBPbeta-mediated commitment to the eosinophil lineage. Expression of FOG in eosinophils led to a loss of eosinophil markers and the acquisition of a multipotent phenotype, and constitutive expression of FOG in multipotent progenitors blocked activation of eosinophil-specific gene expression by C/EBPbeta. Our results show that FOG is a repressor of the eosinophil lineage, and that C/EBP-mediated down-regulation of FOG is a critical step in eosinophil lineage commitment. Furthermore, our results indicate that maintenance of a multipotent state in hematopoiesis is achieved through cooperation between FOG and GATA-1. We present a model in which C/EBPbeta induces eosinophil differentiation by the coordinate direct activation of eosinophil-specific promoters and the removal of FOG, a promoter of multipotency as well as a repressor of eosinophil gene expression.
Animals↗
Correlated switch binding and signaling in bacterial chemotaxis.
In Escherichia coli, swimming behavior is mediated by the phosphorylation state of the response regulator CheY. In its active, phosphorylated form, CheY exhibits enhanced binding to a switch component, FliM, at the flagellar motor, which induces a change from counterclockwise to clockwise flagellar rotation. When Ile(95) of CheY is replaced by a valine, increased clockwise rotation correlates with enhanced binding to FliM. A possible explanation for the hyperactivity of this mutant is that residue 95 affects the conformation of nearby residues that potentially interact with FliM. In order to assess this possibility directly, the crystal structure of CheY95IV was determined. We found that CheY95IV is structurally almost indistinguishable from wild-type CheY. Several other mutants with substitutions at position 95 were characterized to establish the structural requirements for switch binding and clockwise signaling at this position and to investigate a general relationship between the two properties. The various rotational phenotypes of these mutants can be explained solely by the amount of phosphorylated CheY bound to the switch, which was inferred from the phosphorylation properties of the mutant CheY proteins and their binding affinities to FliM. Combined genetic, biochemical, and crystallographic results suggest that residue 95 itself is critical in mediating the surface complementarity between CheY and FliM.
Bacterial Proteins↗
Determination of palladium in airborne particulate matter in a German city.
The part of palladium in ambient urban air that is bound to particles and soluble in aqua regia was determined by means of sorbent extraction, coupled with graphite furnace atomic absorption spectrometry (GFAAS) and laser absorption fluorescence spectrometry (LAFS). Samples of about 200 m3 air were taken in a suburb of Berlin, Germany. The coupling of the selective and automated pre-concentration procedure for Pd as N,N-diethyl-N'-benzoylthiourea complex with the respective detection methods proved to be sufficiently sensitive. Severe interference with other matrix constituents, occurring mainly by direct LAFS detection, could be overcome and the detection limit was improved tremendously. The concentration of Pd in ambient air was determined to be in the range from 0.2 to 14.6 pg/m3.
Air Pollutants↗
Increased hypoxic ventilatory response during hypovolemic stress imposed through head-up-tilt and lower-body negative pressure.
The aim of this study was to quantify the influence of head-up-tilt (HUT) on the isocapnic hypoxic ventilatory response (HVR) in man, and to investigate the effect of orthostatic blood shifts separately from other gravitational effects by the application of lower-body negative pressure (LBNP) with subjects in a horizontal position. HVR was measured in 15 subjects during passive HUT from 0 degrees to 85 degrees as well as during -7 degrees head-down-tilt and while they were in a sitting position. In a subgroup of eight subjects the effect of 85 degrees HUT was compared to a corresponding LBNP of -70 mbar on HVR. Moreover, by imposing graded HUT (7 degrees, 15 degrees, 30 degrees, 50 degrees) and LBNP (-15, -30 mbar) we studied the effect of low-level orthostatic stress on HVR. Ventilation, end-tidal partial pressure of CO2, heart rate and blood pressure were recorded continuously for 1 min before, and during HVR. HVR was significantly increased by approximately equal to 50% through both 85 degrees HUT and -70 mbar LBNP as compared to 0 degrees and 0 mbar, respectively, at unchanged mean arterial pressure. Low-level HUT and LBNP had no effect on HVR. It was concluded that the orthostatic HVR increase may be attributable to caudal blood shifts (i.e., central hypovolemia). This HVR increase requires a pronounced hypovolemic stress but no decrease in arterial blood pressure. It is suggested that a central interaction of arterial and cardiopulmonary baroreceptors is underlying this response. Their separate contribution remains to be assessed.
Adult↗
Short cut of protein purification by integration of cell-disrupture and affinity extraction.
Screening strategies based on functional genomics require the isolation of gene products of several hundred cDNA clones in a fast and versatile manner. Conventional purification strategies will fail to accomplish this goal within a reasonable time frame. In order to short-cut these procedures, we have developed a combination of cell disintegration and affinity technique for rapid isolation and purification. For our purpose, tagged proteins have been produced in yeast by fusing the FLAG-sequence adjacent to the 5' end of cDNAs coding for the respective protein. The example of an over-expressed FLAG-tagged fusion protein, human serum albumin (HSA), was released into the cytoplasm. Detection and purification of the FLAG-fusion protein were carried out by using a mouse monoclonal antibody directed against the FLAG-peptide. For purification purposes, the antibody was immobilized on PROSEP magnetic glass beads. These magnetic glass beads with 500 microns diameter have been investigated for disintegration of yeast and simultaneous capturing of the target protein. After 60 s, 90% of the maximal disintegration level was achieved when a ratio of 20 microliters yeast cell suspension and 100 microliters glass are vortexed. After a wash step, the FLAG-fusion proteins have been eluted with chelating agents such as EDTA. The short-cut procedure has been compared to a conventional purification strategy using an affinity chromatography process. Due to the highly favorable binding characteristics of the applied immunoaffinity sorbent the yield observed in batch operation was 90% and purity in the range of 70-80%.
Amino Acid Sequence↗
A randomized placebo-controlled trial of lisofylline in HLA-identical, sibling-donor, allogeneic bone marrow transplant recipients. The Lisofylline Marrow Transplant Study Group.
The purpose of the study was to evaluate the effect of lisofylline (LSF) on engraftment, regimen-related toxicities (RRT), and mortality in patients undergoing allogeneic bone marrow transplantation (BMT). We performed a multicenter, randomized placebo-controlled trial in 60 patients with hematologic malignancies receiving BMT from HLA-identical sibling donors. Patients were randomized to receive either placebo, 2 mg/kg LSF or 3 mg/kg LSF every 6 h, beginning before conditioning and continuing to day 21 or hospital discharge. Treatment groups were balanced with respect to conditioning regimen and disease stage. However, significantly more patients in the 2 mg/kg LSF group were at high risk for RRT due to performance status >/=1, age >/=40 years, and prior exposure to CMV. Nausea and vomiting were the only adverse events observed in a higher proportion of LSF-treated patients that led to study withdrawal in six of 42 patients (14%). The times to neutrophil recovery to >/=500/microl and platelet recovery (>20 000/microl) were not improved by LSF treatment. Nevertheless, no patient who received treatment with 3 mg/kg LSF developed a documented infection between day 0 and 35 or had a serious or fatal infection between day 0 and 100 (P = 0.003 vs placebo for both). The day-100 survival rate was also significantly improved in the 3 mg/kg LSF group (89%), compared with either the 2 mg/kg LSF (48%) or placebo (61%) groups (log-rank test, 3 mg/kg LSF vs placebo, P = 0. 026). We conclude that treatment with LSF 3 mg/kg reduced the incidence of infections and improved 100-day survival in patients receiving related-donor allogeneic bone marrow transplantation. Bone Marrow Transplantation (2000) 25, 283-291.
Adult↗
[Multi-sequential arterial chemoembolization of advanced hepatocellular carcinomas: computerized tomography follow-up parameters for evaluating effectiveness of therapy].
PURPOSE: An evaluation of clinical and computed tomography parameters for the transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). MATERIAL AND METHODS: Retro- and prospective analysis of 123 TACE procedures in 37 patients (mean age: 63.3 years). RESULTS: Overall mean survival rate for all treated patients was 785 days with a mean value of 387 days. The 1 year survival rate was 62%. Quantitative tumor volumetry revealed a significant difference in survival rate with a mean value of 678 days for patients with a reduction of tumor volume between 0 and 50%, 976 days for a volume reduction of 51-100% and 277 days for an increase in tumor volume during therapy. Patients with a high lipiodol retention presented improved survival data (902 days) versus patients with a low lipiodol retention (513 days). Homogeneous retention of lipiodol was a positive factor on survival as compared to an inhomogenous form of retention. CONCLUSION: In patients with a positive therapy response after TACE the prognosis can be improved by repeated embolization.
Aged↗
Electrocardiographic guidance in placing central venous catheters.
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Catheterization, Central Venous↗
Diuretic effect of hypoxia, hypocapnia, and hyperpnea in humans: relation to hormones and O(2) chemosensitivity.
We studied the contributions of hypoxemia, hypocapnia, and hyperpnea to the acute hypoxic diuretic response (HDR) in humans and evaluated the role of peripheral O(2) chemosensitivity and renal hormones in HDR. Thirteen healthy male subjects (age 19-38 yr) were examined after sodium equilibration (intake: 120 mmol/day) during 90 min of normoxia (NO), poikilocapnic hypoxia (PH), and isocapnic hypoxia (IH) (days 1-3, random order, double blind), as well as normoxic voluntary hyperpnea (HP; day 4), matching ventilation during IH. O(2) saturation during PH and IH was kept equal to a mean level measured between 30 and 90 min of breathing 12% O(2) in a pretest. Urine flow during PH and IH (1.81 +/- 0.92 and 1.94 +/- 1.03 ml/min, respectively) but not during HP (1.64 +/- 0.96 ml/min) significantly exceeded that during NO (control, 1.38 +/- 0.71 ml/min). Urine flow increases vs. each test day's baseline were significant with PH, IH, and HP. Differences in glomerular filtration rate, fractional sodium clearance, urodilatin, systemic blood pressure, or leg venous compliance were excluded as factors of HDR. However, slight increases in plasma and urinary endothelin-1 and epinephrine with PH and IH could play a role. In conclusion, the early HDR in humans is mainly due to hypoxia and hypocapnia. It occurs without natriuresis and is unrelated to O(2) chemosensitivity (hypoxic ventilatory response).
Adult↗
Lymphocytes migrate from the blood into the bronchoalveolar lavage and lung parenchyma in the asthma model of the brown Norway rat.
Lymphocyte migration from the blood into the lung has been suggested as being responsible for the increase of lymphocytes, in particular CD4 T cells, in the bronchoalveolar lavage (BAL) and bronchial mucosa in human asthma, but so far there has been no direct proof. We studied lymphocyte immigration and lymphocyte subpopulations in three lung compartments in ovalbumin (OVA)-sensitized and -challenged brown Norway (BN) rats. Increased numbers of CD4 and interleukin 2 (IL-2) receptor-positive T cells were found in the BAL and lung parenchyma in treated animals, but also increased numbers of CD8 T cells, B cells, and natural killer (NK) cells. For direct proof of lymphocyte migration from the blood into the lung, leukocytes were labeled with a fluorescent dye, 5- (and 6-) carboxyfluorescein-diacetate-succinimidyl-ester (CFSE), and injected intravenously immediately prior to OVA aerosol challenge. One day after challenge the number of CFSE(+), i.e., newly immigrated lymphocytes, was determined by flow cytometry gated on the lymphocyte cluster. A 15 times (1.5 times) higher number of CFSE(+) lymphocytes was found in the BAL (the lung parenchyma) of treated animals in comparison with control rats. In the BAL 51.8% of CFSE(+) cells were CD4-positive (parenchyma 72.7%) and 29.4% IL-2 receptor-positive (parenchyma 34.2%). There was no difference whether the leukocytes for labeling and injection were obtained from untreated or from OVA-sensitized donor animals. Our data show that lymphocyte immigration is at least in part responsible for the increase in lymphocyte numbers in the BAL and lung parenchyma in this animal asthma model.
Animals↗
Protein expression strategies for identification of novel target proteins.
Identification of new target proteins is a novel paradigm in drug discovery. A major bottleneck of this strategy is the rapid and simultaneous expression of proteins from differential gene expression to identify eligible candidates. By searching for a generic system enabling high throughput expression analysis and purification of unknown cDNAs, we evaluated the YEpFLAG-1 yeast expression system. We have selected cDNAs encoding model proteins (eukaryotic initiation factor-5A [eIF-5A] and Homo sapiens differentiation-dependent protein-A4) and cDNA encoding an unknown protein (UP-1) for overexpression in Saccharomyces cerevisiae using fusions with a peptide that changes its conformation in the presence of Ca2+ ions, the FLAG tag (Eastman Kodak, Rochester, NY). The cDNAs encoding unknown proteins originating from a directionally cloned cDNA library were expressed in all three possible reading frames. The expressed proteins were detected by an antibody directed against the FLAG tag and/or by antibodies against the model proteins. The alpha-leader sequence, encoding a yeast mating pheromone, upstream of the gene fusion site facilitates secretion into the culture supernatant. EIF-5A could be highly overexpressed and was secreted into the culture supernatant. In contrast, the Homo sapiens differentiation-dependent protein-A4 as well as the protein UP-1, whose cDNA did not match to any known gene, could not be detected in the culture supernatant. The expression product of the correct frame remained in the cells, whereas the FLAG-tagged proteins secreted into the supernatant were short, out-of-frame products. The presence of transmembrane domains or patches of hydrophobic amino acids may preclude secretion of these proteins into the culture supernatant. Subsequently, isolation and purification of the various proteins was accomplished by affinity chromatography or affinity extraction using magnetizable beads coated with the anti-FLAG monoclonal antibody. The purity of isolated proteins was in the range of 90%. In the case of unknown cDNAs, the expression product with the highest molecular mass was assumed to represent the correct reading frame. In summary, we consider the YEpFLAG-1 system to be a very efficient tool to overexpress and isolate recombinant proteins in yeast. The expression system enables high throughput production and purification of proteins under physiological conditions, and allows miniaturization into microtiter formats.
Blotting, Western↗
Pharmacoeconomic analysis of liposomal amphotericin B versus conventional amphotericin B in the empirical treatment of persistently febrile neutropenic patients.
PURPOSE: In a randomized, double-blind, comparative, multicenter trial, liposomal amphotericin B was equivalent to conventional amphotericin B for empirical antifungal therapy in febrile neutropenic patients, using a composite end point, but was more effective in reducing proven emergent fungal infections, infusion-related toxicities, and nephrotoxicity. The purpose of this study was to compare the pharmacoeconomics of liposomal versus conventional therapy. PATIENTS AND METHODS: Itemized hospital billing data were collected on 414 patients from 19 of the 32 centers that participated in the trial. Hospital length of stay and costs from the first dose of study medication to the time of hospital discharge were assessed. RESULTS: Hospital costs from the time of first dose to discharge were significantly higher for all patients who received liposomal amphotericin B ($48,962 v $43,183; P =.022). However, hospital costs were highly sensitive to the cost of study medication ($39,648 v $43,048 when drug costs were not included; P =.416). Using decision analysis models and sensitivity analyses to vary the cost of study medications and the risk of nephrotoxicity, the break-even points for the cost of liposomal therapy were calculated to range from $72 to $87 per 50 mg for all patients and $83 to $112 per 50 mg in allogeneic bone marrow transplant patients. CONCLUSION: The cost of liposomal amphotericin B and patient risk for developing nephrotoxicity play large roles in determining whether liposomal amphotericin B is cost-effective as first-line empirical therapy in persistently febrile neutropenic patients.
Adult↗