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Biomedical subjects

R Wagner

Publications and source records attributed to R Wagner.

At least 253 records · Page 14Linked to original sources
PubMed1994

The Escherichia coli ribosomal RNA leader: a structural and functional investigation.

The structure of the E. coli ribosomal RNA leader was analyzed by treatment with single and double strand specific ribonucleases and by chemical modification. The experimentally derived data together with secondary structure calculations according to minimum free energy was used to construct a secondary structure model. The binding of purified Nus proteins to the ribosomal leader RNA was further tested. Contrary to the recently reported interactions of NusB and NusE with a nut RNA sequence we obtained evidence that the presence of NusA and NusE resulted in protection against hydroxyl radical reaction of the leader nut elements boxA, boxB and boxC. The possible significance of this interaction is discussed. In the second part of the study we analyzed effects of leader mutations, which are known to affect cell growth, on the activity of ribosomes in vivo. A system was used able to distinguish the proportion of ribosomes assembled from rRNA of chromosomal origin (wild type) and plasmid origin (mutant). It turned out that the amount of 16S RNA transcribed from genes with point mutations in the leader region decreased if ribosomal pools with different translational activities were compared. High amounts of transcripts from mutant operons were present in the free ribosomal RNA and the free 30S fractions. Significantly less 16S RNA transcripts from the mutated genes were detected in the functionally active and homogeneous 70S tight couple preparations, and even less in the polysome fraction involved in active translation. The results allow a better understanding of the function of rRNA leader sequences in structure formation and correct ribosome biogenesis.

Bacterial Proteins↗
PubMed1994

Lack of immunohistological changes in the islets of nondiabetic, autoimmune, polyendocrine patients with beta-selective GAD-specific islet cell antibodies.

We examined the pancreases from three nondiabetic, autoimmune, polyendocrine patients with islet cell antibodies (ICAs) and glutamic acid decarboxylase (GAD) antibodies who died without developing insulin-dependent diabetes mellitus (IDDM). All three patients had the beta-selective GAD-specific ICA subtype and antibodies to the GAD-derived 50 kD tryptic fragment. None had whole islet ICA or antibodies to the non-GAD-derived 37k islet antigen, which appear to be more closely associated with IDDM than antibodies to GAD. The three patients also were negative for insulin autoantibodies. Islets within pancreas from patients 1 and 2 appeared well preserved as assessed by hematoxylin and eosin staining. In these two patients, insulin content, as assessed by indirect immunofluorescence on cryostat sections, was normal. Patient 3 had a prolonged postmortem time, and the islet insulin content was reduced slightly. In all three pancreases, no evidence was found of increased human leukocyte antigen class I or de novo class II molecule expression on islet cells, and islet infiltration by T- or B-cells or macrophages was not detected. Islet capillary endothelial cells did not show signs of hypertrophy. No immunoglobulin or complement deposition within or around islets was found. These data indicate that humoral GAD autoimmunity does not necessarily associate with visible beta-cell damage.

Adenocarcinoma↗
PubMed1994

[Pouches of the upper gastrointestinal tract].

The own findings about the functional behavior of the gastric substitute together with the results from the literature demand a jejunal J-pouch after gastrectomy, if it is not a palliative resection. It is an open question, whether the good experience with the Roux-en-Y-pouch-reconstruction--only 15 min. more time of operation, low rate of complications--allows a wider indication for this procedure.

Anastomosis, Roux-en-Y↗
PubMed1994

Induction of a MHC class I-restricted, CD8 positive cytolytic T-cell response by chimeric HIV-1 virus-like particles in vivo: implications on HIV vaccine development.

New insights into HIV-pathogenesis suggest that the cell mediated immune response might play a crucial role in controlling HIV infection by suppressing HIV-replication in CD4-positive cells by a lymphokine-like soluble factor and by killing HIV-infected cells via classical CTL mediated lysis. This type of a cellular immune response rather than an antibody response seems to be most promising to protect if not from infection, so at least from disease. Therefore rationally designed candidate vaccines should be capable of inducing a cell mediated immunity in addition to a humoral immune response. In order to avoid adverse side effects upon immunization, carefully selected antigens and epitopes should be presented in a favourable manner to the immune system. In previous experiments, we could demonstrate that the gag-polyprotein precursor, known to include a series of T-helper and CTL epitopes, assembles to highly immunogenic, complete noninfectious HIV-1 virus-like particles (VLP). Based on these VLP we developed a novel antigen presentation system, which allows the presentation of selected epitopes derived from HIV reading frames other than gag to the immune system. Alternatively complete derivatives of the HIV-1 external glycoprotein can be presented by the VLP. Immunological analysis of different VLP preparations in a BALB/c mouse model revealed the induction of a strong CTL response. The significance of these observations for future vaccine strategies is discussed.

AIDS Vaccines↗
PubMed1994

[Technique and significance of the Kock pouch].

The development of the continent ileostoma (Kock pouch) is delineated and its results are reviewed. Leading centers achieved continence in more than 90%. High rates of complications and relaparotomies in the early phase could be significantly reduced by technical modifications. Development of ileoanal pouch procedures have, however, confined the continent ileostomy to special indications.

Adenomatous Polyposis Coli↗
PubMed1994

[Pelvic pouches].

Since Nissen performed his first ileo-anal anastomosis for a benign large bowl disease in 1933, restorative proctocolectomy has undergone substantial developments, thus especially in the last two decades. Different pouch designs (J-, S-, W- and H-pouch) obtain normal defecation in patients treated with proctocolectomy. Many groups prefer the J-Pouch for it's technical simplicity and good results.

Adenomatous Polyposis Coli↗
PubMed1994

[Techniques of follow-up examination of the ileoanal and colo-anal pouch].

For the assessment of ileoanal and coloanal pouches different diagnostic tests should be applied. Apart from case history and rectal digital examination the most important methods comprise a radiologic evaluation of the pouch and its afferent loop as well as anorectal manometry for the assessment of pouch motility and sphincter function. Increasingly transanal endosonography is being used for the precise examination of size, volume, and shape of ileoanal and coloanal pouches. The afferent loop is also easily accessible to endosonography, e.g. for evaluation of bowel wall morphology and function. Furthermore, in cases of coloanal pouches following an oncologic lower anterior resection, endosonography is used in follow-up examinations for the detection of local tumor recurrence.

Adenomatous Polyposis Coli↗
PubMed1994

[Left heart failure in anesthesia in a child pretreated with propranolol--case report].

A 13-year-old girl suffering from nephrogenic hypertension, treated with high-dose propranolol and other antihypertensive medication, developed acute hypoxaemia (oxygen saturation at 60% at 100% oxygen ventilation) shortly after induction of anaesthesia. The auscultatory findings first suggested bronchospasm; however, specific measures failed to improve pulmonary function. The planned procedure was delayed and further investigations showed acute left heart failure due to beta-blockade combining with general anaesthesia.

Adolescent↗
PubMed1994

From HIS to IAIMS: expanding the scope of information processing applications in a German university hospital.

Since the mid eighties the department of medical informatics at the University Hospital of Giessen (Germany) has been engaged in the development of a comprehensive hospital information system. The installation of a campus wide network has set the basis to provide not only clinical patient-oriented information, but also general information resources for research, medical education and administrative purposes, thus creating an environment which in the U.S. became known as an integrated academic information management system (IAIMS). The underlying concept of the whole approach is to provide one-stop information shopping capabilities at the clinicians and administrators desktop in order to meet the increasing information needs of health professionals with the emerging reality of the potential benefits of computer and communication technologies. This paper describes the various steps performed to realize this concept at Giessen University Hospital and the evaluation results derived from analysis of the acceptance of these new technologies among our hospital staff.

Computer Systems↗
PubMed1994

Early and long-term results of cardiac surgery in dialysis patients.

Cardiac surgery in patients receiving dialysis has a high mortality and morbidity. Early long-term results have been analysed following various cardiac operative procedures. Between 1981 and 1992, 40 patients, of mean age 55.7 (range 31-71) years underwent cardiac surgery. Procedures included coronary artery bypass grafting (20 patients), aortic valve replacement (six), mitral valve replacement (four), aortic valve or mitral valve plus coronary artery bypass grafting (one each), aortic plus mitral valves (two), heart and renal transplantation (one each), atrial septal defect closure (one) and pericardial decortication (three). Before surgery, patients were in the New York Heart Association (NYHA) classes II (5%), III (52.2%) and IV (42.5%). The operative mortality rate was 15%; survivors were in NYHA classes I (3%), II (88.2%) and III (8.8%). There were 11 late deaths. Follow-up at a mean of 35 (range 1-93) months showed actuarial survival rates of 91% (1 year) and 69% (5 years). After coronary artery bypass grafting, survival rates were 95% (1 year) and 72% (5 years). Survivors were in NYHA classes I (4.7%), II (85.5%) and III (9.5%). Cardiac surgery in dialysis patients is associated with an acceptable hospital mortality; quality of life in long-term survivors is increased. Hence, surgical treatment is advocated in patients with symptomatic heart disease. Early diagnosis and surgical intervention in NYHA class II patients may lead to a lower perioperative mortality.

Adult↗
PubMed1994

[Assessing myocardial viability in chronic myocardial infarct with 18F-fluoro-D-glucose positron emission tomography and 99mTc-MIBI SPECT].

The determination of residual viability in regions of myocardial infarcts is of considerable clinical interest. In order to assess residual viability in regions with chronic myocardial infarction, 18 patients with anterior myocardial infarcts and 14 patients with inferior myocardial infarcts as confirmed by ECG and cine ventriculography underwent 99mTc-methoxyisobutyl-isonitrile single photon emission computed tomography (MIBI-SPECT) and 18F-fluoro-D-glucose positron emission tomography (FDG-PET). Tracer uptake was quantified in 13 segments for each patient (a total of 416 segments). MIBI uptake was normalized to the maximal uptake in the heart, FDG uptake was normalized to the maximal uptake of left ventricular segments with normal contraction by cine ventriculography and without significant stenosis of the coronary artery supplying this region. MIBI-SPECT scar and FDG-PET scar were defined as tracer uptake of less than 2.5 SD below mean values of a healthy control group. Both methods scored 258 segments concordantly viable and 74 segments concordantly scar; 61 segments were scored scar by MIBI-SPECT and viable by FDG-PET, 23 segments were scored viable by MIBI-SPECT and scar by FDG-PET (p < 0.0001). In patients with anterior myocardial infarction, 136 segments were scored viable and 53 segments were scored scar by both methods, 29 segments were scored scar by MIBI-SPECT and viable by FDG-PET, 16 were scored discordantly viable by MIBI-SPECT and scar by FDG-PET (p < 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

[Complications of plate osteosynthesis of the femur shaft. An analysis of 199 femoral fractures].

From January 1982 to June 1987 a total of 189 patients with 199 fractures of the femoral shaft were treated by internal plate fixation. Aseptic complications were found in 41 osteosyntheses (20.5%) and were due variously to implant deficiencies (11%: loosening 2.5%, deformation 1.0%, implant fracture 7.5%), delayed union (3%), non-union (4.5%), axial deformities (2.5%) and differences in femoral length (5%). Septic complications were seen in 2.5%. There are three main ways of limiting the rate of aseptic complications: (1) restrictive indications for internal plate fixation or femoral shaft fractures; (2) a precise surgical technique taking account of local biomechanical and biological needs; and (3) generous application of bone grafting.

Adolescent↗
PubMed1994

[Surgical therapy of lung metastases].

The operative treatment of lung metastases is a procedure which is performed world-wide in a carefully selected group of patients. Operative treatment can be performed on the assumption that the treatment of the primary tumor has been successfully completed, that there are no extrapulmonary metastases, and that the patient will be operable under local and general aspects. The success of the operation depends on the complete resection of all visible and palpable metastases. As approach we choose total median sternum splitting or lateral thoracotomy. The most common surgical technique is the atypical resection of the metastases, i.e. the transsegmentectomy. The mortality rate was found between 0.0 and 2.0 (-5.0)%. The aim of the operation is the individual prolongation of life with a good quality. However, some patients can be cured definitively. The 5-year-survival-rate was found between 30 and 45%. Significant prognostic factors are the resectability as well as the tumor-free interval. Of minor importance are the type and class of the primary tumor, a union bilateral metastatic spread, and an involvement of lymph nodes.

Humans↗
PubMed1994

[Autologous fibrin glue from preoperative blood or plasma donors].

Cryoprecipitate was prepared from autologous plasma donation (fresh frozen plasma). The composition of this cryoprecipitate (fibrinogen, factor XIII, fibronectin) meets the requirements for the fibrinogen component of a fibrin glue. The prepared glue has tensile strength values in dura mater gluing as good as the commercial tissue glues.

Blood Donors↗
PubMed1993

Spinal dynorphin immunoreactivity increases bilaterally in a neuropathic pain model.

Increased spinal levels of dynorphin, an endogenous opioid kappa agonist, are seen in models of both chronic and acute hyperalgesia. This study determined the extent and localization of spinal immunoreactive dynorphin following sciatic cryoneurolysis (SCN), a neuropathic pain model produced by a peripheral nerve freeze lesion. SCN results in behaviors associated with neuropathic pain such as autotomy (the gnawing and scratching of the affected limb), touch-evoked and mechanical allodynia, and spontaneous nociceptive behavior. Following SCN, 4 rats that displayed autotomy and 3 rats that did not were randomly chosen for immunohistochemical staining of dynorphin-like immunoreactivity (DLIR). The area of DLIR above a standardized threshold level was quantified in both dorsal horns of each spinal cord section using a computer-assisted image analyzer to express DLIR in pixels. DLIR was observed both ipsilateral and contralateral to the injured peripheral nerve. In addition, the area of DLIR was significantly greater (P = 0.05) in rats that showed autotomy behavior (mean = 52.6 x 10(3) +/- 25.6) compared to rats with no autotomy (mean = 13.8 x 10(3) +/- 4.78). In sharp contrast to the ipsilateral dynorphin increases observed in other neuropathic pain models, we observe a bilateral increase at 21 days following SCN.

Animals↗
PubMed1993

[Immune activity and serum interleukin-2-receptor concentration in autoimmune thyroid diseases].

Serum interleukin-2 receptor (IL-2R) concentrations were compared in 55 patients with thyrotoxicosis (14 men, 41 women, mean age 43.5 +/- 17 years), 18 patients with Hashimoto's thyroiditis (5 men, 13 women, mean age 47 +/- 15 years) and 28 healthy subjects (12 men, 16 women, mean age 30 +/- 10 years). The patients with thyrotoxicosis were divided into three groups depending on the activity or stage of the disease: 17 patients with florid untreated hyperthyroidism, 23 euthyroid patients receiving treatment with antithyroid drugs and 15 patients with thyrotoxicosis in remission after completing one year's antithyroid treatment. The patients with untreated thyrotoxicosis had significantly higher IL-2R values than the euthyroid patients receiving treatment or those in remission (207 +/- 112 vs 139 +/- 66 and 91 +/- 26 U/ml, P < 0.05 and P < 0.01). The IL-2R values of patients with thyrotoxicosis in remission were, however, significantly lower than those of the 28 healthy subjects (126 +/- 34 U/l; P < 0.01) or the euthyroid patients receiving treatment (P < 0.05). The 18 patients with Hashimoto's thyroiditis had significantly lower serum IL-2R values (70 +/- 39 U/ml) than the healthy controls. These data show that the serum IL-2R level depends on the state of thyroid metabolism and on the activity phase of the thyrotoxicosis. The low serum levels of IL-2R in patients with Hashimoto's thyroiditis could signify a genetically determined decrease in IL-2R production or might be linked with the destruction of thyroid tissue by the chronic autoimmune process.

Adult↗
PubMed1993

HIV-1 reverse transcriptase: polymerization properties of the p51 homodimer compared to the p66/p51 heterodimer.

The polymerase activity of the p51 homodimeric form of HIV reverse transcriptase was characterized by activity gel analysis, steady-state kinetic measurements, and processivity assays, and the activity was shown to be highly similar to that for the p66/p51 heterodimer. Recombinant 51- and 66-kDa reverse transcriptase proteins were individually expressed from an HIV-1 Pol gene having an accumulation of natural amino acid mutations compared to the BH10 clone (Ratner et al., 1985). The preparation of an active p51 homodimer critically depended on low temperature during its expression in bacterial cultures. Activity gel analysis demonstrates that refolded p51 protein derived from denatured p66/p51 heterodimer yields an active polymerase. The p51 homodimer has approximately one-half the activity and processivity of the heterodimer, while both enzymes have similar thermostability. Steady-state measurements reveal no significant differences in apparent affinities for substrate or homopolymeric template-primer, suggesting that the subunits in both enzyme forms have similar conformations. Template challenge experiments show that the off-rates for template-primer are lower, but as indicated by primer extension analyses, processivity is less for p51 homodimer. These results show that the RNase H domain is not essential for the assembly of the functional polymerase, but suggest that it enhances processivity.

Amino Acid Sequence↗