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Biomedical subjects

M Krüger

Publications and source records attributed to M Krüger.

At least 55 records · Page 3Linked to original sources
PubMed1999

Quadrileaflet stentless mitral valve replacement.

BACKGROUND: The study evaluates clinical results and hemodynamic parameters one year after implantation of a stentless quadrileaflet mitral valve (QMV). METHODS: Since August 1997 28 patients received the QMV, patient age was 69 +/- 8 years; 13 had predominant mitral stenosis and 15 incompetence, preoperative NYHA functional class was III or IV and cardiac index 1.8 +/- 0.6 L/min/m2. RESULTS: Surgery was performed using a conventional (25) or a minimally invasive approach (3). 20 patients received a medium and 8 a large-size prosthesis, crossclamp time was 58 +/- 19 min. Additional procedures were myocardial revascularization in four, tricuspid repair in two, and left-atrial radiofrequency ablation to restore sinus rhythm in six patients. Perioperative mortality (1) was not valve-related. All other patients were discharged on time. At postoperative, 6-, and 12-months follow-up mean transvalvular pressure gradients were 4.2 +/- 1.5 / 4 +/- 0.9/ 3.8 +/- 1.4 mmHg and mitral valve orifice area index was 1.5 +/- 0.3 / 1.6 +/- 0.3 / 1.6 +/- 0.4, NYHA class was I or II. CONCLUSIONS: The QMV is well suited for mitral valve replacement. The anulo-ventricular continuity is preserved and the QMV function resembles native mitral valve function. If its performance is maintained in the long term the QMV may be the mitral prosthesis of choice.

Aged↗
PubMed1999

[Examination of systemic tumor necrosis factor activity under physiologic and pathophysiologic conditions].

Tumor necrosis factor (TNF) activity in the circulation of several animal species was determined by a bioassay, using the murine cell line L929. In healthy adult cattle, horses, pigs and dogs, species specific differences of systemic TNF activity were visible. In cattle, TNF activity in the circulation increased during growing up from calf to adult animal. In cattle suffering from various diseases, unchanged, elevated, but also reduced systemic TNF activity have proved to possess clinical relevance. Low systemic TNF activity frequently occurs during lethal inflammatory diseases and may be an indicator of generalized monozyte paralysis.

Aging↗
PubMed1999

[Effect of lactation state (1st-20th week of lactation) on dynamics of C-reactive protein (CRP) in initial quarter milk samples in relation to somatic cell count, lactose content and blood serum CRP levels].

The concentration of C-reactive protein (CRP) in milk and blood serum varies during the first half of lactation. Somatic cell count and lactose content also depend on the stage of lactation. CRP blood serum levels show a distinct tendency to increase from the 2nd to the 20th week of lactation. In contrary the milk CRP content decreases from the 1st week to the end of the 2nd month post partum and increases again from the 8th to the 20th week post partum. Somatic cells and CRP-concentrations in milk increase parallelly but the lactose content shows a contrary pattern in the first five months of lactation.

Animals↗
PubMed1999

[Investigations on the behavior of C-reactive protein, cell count, lactose content as well as electric conductivity in quarter milk samples of subclinically diseased quarters of the udders in relation to bacteriologic results].

Inflammations of the udder influence the amount of somatic cells and lactose as well as electrical conductivity in milk. They are often caused by bacterial agents. Similar reactions are to be seen in relation to C-reactive protein (CRP). The amount of CRP in milk depends on concentration and characteristics of the agents and the phase of inflammation. We found a significant increase of CRP in milk samples with Streptococcus (Sc.) uberis. There was no significant difference in CRP concentrations in samples with coagulase positive Staphylococcus spp. (CPS) and bacteriological negative samples and such with Corynebacterium (C.) bovis, Micrococcus spp. and Staphylococcus (S.) epidermidis. We only found high correlations to the amount of somatic sells and lactose as well as electrical conductivity in samples with Sc. uberis. The results of our investigations show that CRP may be a parameter for better understanding subclinical inflammations of udder.

Animals↗
PubMed1999

Regression of left ventricular hypertrophy after stentless versus conventional aortic valve replacement.

The goal of this study was to analyze regression of left ventricular hypertrophy after randomization to conventional biological versus stentless aortic valve replacement. Stentless (Freestyle, Toronto, n = 106) or conventional biological aortic valves (Carpentier-Edwards, n = 74) were evaluated prospectively. Preoperatively there were no differences with regard to aortic valve pathology, left ventricular function, and pressure gradients between the two patient groups. The patient annulus index (13.55 vs. 13.46 mm; NS) measured intraoperatively was used as baseline for further comparison. Postoperatively, left ventricular mass index was 213+/-77 g/m2 (stentless) compared with 202+/-72 (conventional group) g/m2 (NS), whereas after 6 months it was 141+/-41 g/m2 in the stentless and 170+/-43 g/m2 in the conventional group (P<.05). Regression of left ventricular hypertrophy occurs in all patients after aortic valve replacement. Nevertheless, the use of stentless bioprostheses leads to a significant enhancement, which may result in a reduction of the cardiac risk profile for the patient.

Aged↗
PubMed1999

Stentless mitral valve replacement using the quattro valve.

This study analyzed early clinical results after stentless mitral valve (Quadrileaflet Mitral Valve (QMV)/Quattro) implantation. A total of 28 patients have received a Quattro valve since August 1997. Patient age was 69+/-8 years; the underlying disease was mitral incompetence (14) and stenosis (13). Preoperative New York Heart Association functional class was 3.2+/-0.4 and cardiac index was 1.8+/-0.6. Mean cross-clamp duration was 58+/-19 minutes. Twenty patients received a 28-mm prosthesis, and eight patients received a 30-mm prosthesis. Four patients had myocardial revascularization, two had tricuspid valve repair, and six had radiofrequency ablation therapy to restore sinus rhythm. Mortality (1) was nonvalve related. Reoperation was necessary in two patients for posterior paravalvular leakage (1) and for functional stenosis (1). Echocardiography showed satisfactory hemodynamic function. By stentless mitral valve implantation the annuloventricular continuity is preserved to stabilize left ventricular function. The Quattro valve resembles native mitral valve function and is well suited for mitral valve replacement.

Aged↗
PubMed1998

Integrity of a Zn finger-like domain in SamB is crucial for morphogenesis in ascomycetous fungi.

Genetic features determine the site of polarized growth in filamentous fungi and lead to hyphal tip extension or subapical branching. We have isolated the samB gene (suppressor of anucleate metulae) of Aspergillus nidulans which encodes a 66 kDa protein carrying an atypical Cys4 and an additional Cys2/His/Cys Zn finger motif at the carboxy-terminus. Such novel Zn finger-like domains have recently been found in several other developmental regulators in organisms ranging from yeast to man. Deletion of this domain at the carboxy-terminus of SamB led to premature hyphal ramification, mislocalization of septa and suppression of the asporogenous phenotype of the developmental mutant aps (anucleate primary sterigmata). A DeltasamB deletion strain displayed an identical phenotype. A homologous gene in Saccharomyces cerevisiae was also characterized whose deletion resulted in a multi-budding phenotype; thus it was named MUB1. An underlying common mechanism for both genes in determination of the onset of polarized growth and its links to other cellular developmental processes is discussed.

Amino Acid Sequence↗
PubMed1998

Postoperative complications after bronchoplastic procedures in the treatment of bronchial malignancies.

OBJECTIVE: The purpose of this study was to determine the frequency of postoperative complications after bronchoplastic procedures in the treatment of pulmonary malignant tumors and to analyze the factors influencing the complication rate. METHODS: During a 5-year-period (1992-1996) 79 patients (68 male, 11 female, mean age 57 years) underwent reconstructive operations for bronchial malignancies. We performed 58 bronchoplastic procedures and 21 combined broncho- and angioplastic procedures. Among the bronchoplastic procedures the number of sleeve resections (n = 44) and wedge resections (n = 35) were comparable. RESULTS: Fifty-nine patients (74,7%) showed a regular postoperative course; 12 patients (15,2%) had severe postoperative complications (death, re-operation). Concerning the primary operation the operative 30-day mortality was 5.1% (n = 4) and including the two deaths after re-operation it was 7.6% (n = 6). After subdividing the patients into three groups (severe, less severe and no complications) we tried to determine predictors for occurrence of postoperative complications. There was a higher rate of severe complications in the age group 61-70 years (6/25 = 24%) as compared with younger patients between 51 and 60 years (4/38 = 10,5%; P < 0,05). Concerning the location, the outcome was better after sleeve- or wedge lobectomies of the upper lobes (four complications/51 patients = 7.8%) compared with procedures of the lower lobes (3/14 = 21.4%). The data could not prove a lower frequency of severe postoperative complications or specific morbidity after pleural coverage following bronchial sleeve resection. The complication rate was higher when sleeve resection of the bronchus was performed (10/44 = 22.7%) as compared with wedge resections (2/35 = 5.7%; P = 0,011) and after resection of T3/T4 tumors (6/28 = 21,4%) compared with T1/T2 tumors (4/37 = 10.8%; P < 0,05). CONCLUSIONS: Bronchoplastic procedures represent a fairly safe therapy opportunity in patients with centrally localized bronchial carcinoma and compromised or uncompromised pulmonary function. In this study the complication rate was higher after sleeve resection of the bronchus as compared with wedge resection. Pleural coverage of the anastomosis was not effective to prevent major complications due to dehiscence of the bronchial anastomosis. A pedicled muscle flap could be a valuable alternative.

Bronchi↗
PubMed1998

Poisoning with tilidine and naloxone: toxicokinetic and clinical observations.

The opioid analgesic tilidine and its metabolites were detected by high performance liquid chromatography (HPLC) with UV-detection in serum from a 28 year-old woman who ingested 100 ml Valoron (o)N containing 6.94 g of tilidine and about 0.56 g of naloxone with suicidal intention. Data on the toxicokinetics of tilidine in severe poisonings are missing. Therefore we followed serum concentrations of tilidine and metabolites for 48 or 96 h and for the first time calculated basic kinetic parameters in a massive life threatening poisoning. Serum concentration of tilidine 3 h after ingestion was 38.1 mg/l which is about 70 times of the upper therapeutic level in man and about ninefold above toxic concentrations known so far. The concentration of nortilidine, the primary active metabolite at this time was 18.8 mg/l. The terminal elimination half life's of tilidine and nortilidine were explicit, prolonged with 23.9 and 13.9 h respectively. The competitive opiate antagonist naloxone, which is added as a part of the industrially produced preparation Valoron N solution to minimise oral abuse is not able to prevent ventilatory depression in massive overdoses.

Adult↗
PubMed1998

[Thoracic surgery relevant indications for adjuvant and/or palliative measures in breast carcinoma].

Metastatic lesions of breast cancer represent rare indications for operation in thoracic surgery. Only in case of persistent malignant pleural effusions or in case of tumour progress despite all other available therapy modalities thoracic surgery can be indicated. Over a period of 5 years between 1993 and 1997 53 patients with metastatic breast cancer were treated in our institution. 36 pts. suffered from persistent pleural effusions, 13 pts. had pulmonary metastases and 4 pts. had metastases involving the chest wall. In all these patients the disease could not be controlled by conservative measures. Our experiences are the following: Thoracoscopy is the diagnostic method of choice for pleural effusions in patients with malignant tumors. If a malignant pleural effusion is confirmed, a talc poudrage represents the most reliable treatment to palliate the dyspnea. The resection of a single solitary pulmonary metastasis can be indicated to confirm the histologic type of the nodule. Resections for centrally localized lesions causing hemoptysis or atelectasis represent rare occasions. Metastatic lesions of breast cancer involving the ribs or the sternum are resected in order to confirm the histologic diagnosis. According to the literature these procedures, with a 5-year survival rate of 50% and without perioperative mortality, can be beneficial.

Biopsy↗
PubMed1998

[Generation and characterization of avian vitelline antibodies against lipopolysaccharide and lipid A. 1. Induction and preparation of specific egg yolk antibodies (IgY) against endotoxins].

The immunisation of mammals with LPS- and lipid A-antigens leads to the production of specific antibodies. In the present study, we describe the generation and preparation of antibodies from egg yolks of immunized chickens. Egg yolk antibodies were raised by immunizing laying hens with five LPS- and three lipid A-preparations from various gram-negative bacteria species in different immunisation protocols. Antibodies from collected egg yolks were extracted and purified by means of several standard methods. The purity of antibody-preparations was measured and compared by SDS-PAGE. Specific antibodies were assayed by two different EIA procedures. It could be shown that the immunisation of hens with LPS- and lipid A-Antigens resulted in the production of specific egg yolk antibodies, regardless of immunisation-scheme and amount of antigen.

Animals↗
PubMed1998

[Effect of transport stress on the content of endotoxin in blood of slaughter pigs].

Stress during transportation of slaughter pigs could lead to an increased level of translocation of endotoxin from the gut. In particular, during longtime transportation increased concentrations of endotoxin in blood are likely. Since nonlethal doses of endotoxin could trigger translocation of bacteria from the gut to systemic organs an endogenous contamination of the carcasses also with human pathogens may occur. Therefore, it is necessary to evaluate transportation regimes of slaughter animals also with regard to food-borne infections and intoxications.

Abattoirs↗
PubMed1998

[Determination of C-reactive protein and neopterin in serum of diseased and bacterially infected swine].

The parameters C-reactive protein (CRP) and neopterin, which are associated with immunological reactions, were investigated in serum of healthy, diseased and with Haemophilus parasuis infected pigs. When comparing diseased young pigs with healthy young pigs significant increases of the CRP- and neopterin concentrations can be seen. The increase of the CRP-concentration was most remarkable. After the infection of SPF-piglets with Haemophilus parasuis, significantly decreased neopterin concentrations and increased CRP concentrations were determined in comparison with non-infected animals. The animals with the symptoms of arthritis and disorders of the central nervous system showed the lowest neopterin concentrations and the highest concentrations of CRP. It seems that CRP and neopterin are interesting serum parameters in pigs with regard to the recognition of immunological reactions after illness or infection.

Animals↗
PubMed1997

Synaptopodin: an actin-associated protein in telencephalic dendrites and renal podocytes.

Synaptopodin is an actin-associated protein of differentiated podocytes that also occurs as part of the actin cytoskeleton of postsynaptic densities (PSD) and associated dendritic spines in a subpopulation of exclusively telencephalic synapses. Amino acid sequences determined in purified rat kidney and forebrain synaptopodin and derived from human and mouse brain cDNA clones show no significant homology to any known protein. In particular, synaptopodin does not contain functional domains found in receptor-clustering PSD proteins. The open reading frame of synaptopodin encodes a polypeptide with a calculated Mr of 73.7 kD (human)/74.0 kD (mouse) and an isoelectric point of 9.38 (human)/9. 27 (mouse). Synaptopodin contains a high amount of proline ( approximately 20%) equally distributed along the protein, thus virtually excluding the formation of any globular domain. Sequence comparison between human and mouse synaptopodin revealed 84% identity at the protein level. In both brain and kidney, in vivo and in vitro, synaptopodin gene expression is differentiation dependent. During postnatal maturation of rat brain, synaptopodin is first detected by Western blot analysis at day 15 and reaches maximum expression in the adult animal. The exclusive synaptopodin synthesis in the telencephalon has been confirmed by in situ hybridization, where synaptopodin mRNA is only found in perikarya of the olfactory bulb, cerebral cortex, striatum, and hippocampus, i.e., the expression is restricted to areas of high synaptic plasticity. From these results and experiments with cultured cells we conclude that synaptopodin represents a novel kind of proline-rich, actin-associated protein that may play a role in modulating actin-based shape and motility of dendritic spines and podocyte foot processes.

Actins↗
PubMed1997

Inhibition of CREB- and cAMP response element-mediated gene transcription by the immunosuppressive drugs cyclosporin A and FK506 in T cells.

The clinically important immunosuppressant drugs cyclosporin A and FK506 (tacrolimus) inhibit in T-cells calcineurin phosphatase activity and nuclear translocation of the cytosolic component of the transcription factor nuclear factor of activated T-cells (NF-ATc) that is involved in the induction of early genes during T-cell activation. This effect has been proposed to explain at least part of the immunosuppressive effect of these drugs. Previous studies in pancreatic islet cell lines have shown that cyclosporin A and FK506 through inhibition of calcineurin interfere also with the function of the transcription factor cAMP response element binding protein (CREB) that is activated by cAMP and calcium signals and binds to cAMP/calcium response elements (CRE). By transient expression of CRE-reporter genes or GAL4-CREB fusion proteins, the present study shows that inhibition of CREB/CRE-directed transcription by cyclosporin A and FK506 occurs in a great variety of cell types including in cell lines derived from tissues in which adverse effects of the immunosuppressants develop. CREB activity and CRE-mediated transcription was blocked by these drugs also in Jurkat T-cells. When taken together with recent evidence for an essential role of CREB in T-cell activation and proliferation, the present results suggest that inhibition of CREB/CRE-directed transcription may be a molecular mechanism of the immunosuppressive effect of cyclosporin A and FK506.

Animals↗
PubMed1997

[Liver transplantation in familial amyloid polyneuropathy. Case report and review of the literature].

A 59-year old male of German origin noticed exercise-independent cardiac arrhythmia two years before admission. An alanine 47 transthyretin variant of Familial Amyloid Polyneuropathy with hypertrophic cardiomyopathy, peripheral sensory-motor polyneuropathy, I, degree AV heart block was diagnosed. To diminish production and deposition of mutant transthyretin and to prevent disease progression orthotopic liver transplantation was performed. Prior to transplant the patient complained of inappetence. Postoperatively, he received a chemically defined enteral nutrition regime that was discontinued after 30 months until return of appetite and weight gain indicated marked improvement. However, a duodenal biopsy still demonstrated amyloid deposits 24 months after transplantation. Echocardiographic findings remained unchanged. Neurologic examination showed an improvement of sensory-motor polyneuropathy with regression of electromyographic changes. Only traces of variant transthyretin were detectable in plasma samples taken 12 months after the operation. During the 3 year follow-up, no additional symptoms have occurred and progression of amyloidosis was prevented. Currently, orthotopic liver transplantation is the only specific treatment to prevent progression of familial amyloid polyneuropathy.

Amyloid↗