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Biomedical subjects

M Betzler

Publications and source records attributed to M Betzler.

At least 19 recordsLinked to original sources
PubMed2000

Pore mutations affecting tetrameric assembly and functioning of the potassium channel KcsA from Streptomyces lividans.

Designed mutations within the Streptomyces lividans kcsA gene resulted in a set of mutant proteins, which were characterized in respect to their assembly and channel activities. (i) The amino acid residue leucine 81 located at the external side of KcsA was found to be exchangeable by a cysteine residue without affecting the channel characteristics. (ii) Substitution of the first glycine (G77) residue within the GYG motif by an alanine or substitution of the tyrosine (Y) residue 78 by a phenylalanine (F) led to mutant proteins which form tetramers of reduced stability. In contrast to the AYG mutant protein, GFG functions as an active K(+) channel whose characteristics correspond to those of the wild-type KcsA channel. (iii) The investigated mutant proteins, which carry different mutations (T72A, T72C, V76A, V76E, G77E, Y78A, G79A, G79D, G79E) within the signature sequence of the pore region, do not at all or only to a very small degree assemble as tetramers and lack channel activity.

Amino Acid Motifs↗
PubMed1998

[Surgical technical guidelines in intestinal ischemia].

Acute occlusive mesenteric ischemia is caused by a local impairment of splanchnic blood flow and poses a particular surgical challenge. Acute superior mesenteric occlusion is a medical/surgical emergency mandating prompt diagnosis (clinical awareness, angiography) and therapy (exploratory laparotomy with possible arterial reconstruction; embolectomy, thrombectomy; and/or bowel resection). The difficulty of early diagnosis is probably the most important cause of the high mortality which varies from 70% to 90% in arterial and functional mesenteric ischemia and from 20% to 70% in an acute thrombosis of the mesenteric veins. Improved survival from nonocclusive mesenteric ischemia is dependent upon the identification of high-risk groups and on aggressive diagnostic and therapeutic measures (intra-arterial infusion of papaverine through the angiographic catheter with or without bowel resection). For assessment of bowel viability, the clinical judgement during first- or second-look exploration is still the most reliable parameter. The surgical management of chronic mesenteric ischemia includes aortomesenteric grafting and transaortic endarterectomy in the majority of patients with comorbidity of cardiovascular arteriosclerotic diseases and results in a high rate of symptom-free patients. Prophylactic reconstruction of visceral arteries is indicated only in certain limited circumstances.

Arteriovenous Shunt, Surgical↗
PubMed1998

[Hospital comparison--status quo and prospects].

Hospitals are competing with each other for the limited financial resources available in the health care sector. Comparison of hospitals is legally required (BPf1V section 5) to improve financial efficiency in the health care sector and make competition between hospitals keener, while also objectivizing it. If comparison of the hospitals is really to enhance profitability or efficiency, and not just to reduce the prices for hospital stays regardless of quality, it must extend to far more than the global figures in the compilation summarizing performance and calculation and the hospital statistics (no. of cases, days of care, length of stay, case lump sums and special fees). Documentation of particular features of the patient population, the potentials of the hospital and description of the treatment processes yield valuable information on capacity and performance level. With rising costs, the danger is growing that the quality and risk dimension of the actual medical treatment will not be promoted with the same enthusiasm by those offering the service. Hospital audit does not only allow a check on the hospital's own situation with regard to performance, quality, efficiency and patient satisfaction, but can also provide a basis of structural planning. The fact is that all efforts made and steps taken by the responsible persons in the hospital to improve the quality of structures, processes and results can only be successful if they are also perceived by the patients, the doctors who refer them and the visitors. If hospital audit is restricted to the bed occupancy and the invoicing data, it is only realistic to expect cuts in performance level. This would be bad for the patient and, in view of the consequent costs, also for the overall costs in the health care sector. Against the backdrop of a future performance-related system of remuneration instead of the principle of covering one's own costs that has been in place hitherto, openness about treatment results gains in importance as a competition parameter for qualified hospitals.

Cost-Benefit Analysis↗
PubMed1997

[Interdisciplinary guidelines: inflammatory bowel diseases (Crohn disease, ulcerative colitis)].

Crohn's disease and ulcerative colitis are characterized by common problems and findings but also disease-specific differences. The most frequent indication for surgery concerns the refractory situation occurring both after and during systematic conservative treatment. The aim of surgery in patients with Crohn's disease is to induce remission of symptoms by removing the segment of diseased bowel. Because of the relatively high rate of postoperative recurrence, extensive resections should be avoided. Proctocolectomy with ileal pouch--anal anastomosis has become the surgical treatment of choice for most patients with uncontrolled ulcerative colitis. This technique offers these patients cure of the disease and in most cases a better quality of life.

Colitis, Ulcerative↗
PubMed1997

[Continuing medical education seminars of the professional society as preparation for specialist certification (surgery specialty and subspecialties)].

The Berufsverband der Deutschen Chirurgen (BDC) established the Academy for Surgical Education and Training and started in 1986 a structured educational program. It consists of an annual congress (Chirurgentag) and different seminars. In the meantime 15 seminars--nine in general surgery and six in surgical specialities such as traumatology and vascular, visceral, and thoracic surgery--are offered annually in 12 different locations in Germany. The basic seminars (since 1986) 5,264 and the specialised seminars (since 1992) have attracted 1,078 participants. The evaluation of these educational efforts by the BDC in respect to the annual certifications by the official authorities (Landesärztekammer, Bundesärztekammer) demonstrates a high level of acceptance.

Congresses as Topic↗
PubMed1997

[Performance and cost transparency as quality assurance measures].

The use of a Hospital Information System--Network Configuration, Information--Storage and Retrieval, Medical-Administration and -Documentation--lead in the Department of Surgery to positive effects concerning transparency and consciousness of costs and allowed an accurate budget planing and controlling of proceeds.

Budgets↗
PubMed1997

[Embolism detection after carotid endarterectomy].

Embolic phenomena, early after endarterectomy of the internal carotid artery, were observed in 8 of 28 cases. No patient suffered from ischemic events. 24 h later, no further embolic signals could be detected. These and other observations of an increased risk of perioperative thrombosis and cerebral infarction, in the case of persistent embolic signals during the early recovery period, confirm the probably important role of the transcranial emboli detection in the monitoring of carotid surgery.

Aged↗
PubMed1995

A prokaryotic potassium ion channel with two predicted transmembrane segments from Streptomyces lividans.

We report the identification, functional expression, purification, reconstitution and electrophysiological characterization of an up to now unique prokaryotic potassium ion channel (KcsA). It has a rectifying current-voltage relationship and displays subconductance states, the largest of which amounts to A approximately equal to 90 pS. The channel is blocked by Cs- ions and gating requires the presence of Mg2+ ions. The kcsA gene has been identified in the gram-positive soil bacterium Streptomyces lividans. It encodes a predicted 17.6 kDa protein with two potential membrane-spanning helices linked by a central domain which shares a high degree of similarity with the H5 segment conserved among eukaryotic ion channels. Multiple alignments of deduced amino acids suggest that the novel channel has the closest kinship to the S5, H5 and S6 regions of voltage-gated K+ channel families, mainly to the subfamily represented by the Shaker protein from Drosophila melanogaster. Moreover, KcsA is most distantly related to eukaryotic inwardly rectifying channels with two putative predicted transmembrane segments.

Amino Acid Sequence↗
PubMed1992

Soluble interleukin-2 receptor, interleukin-6 and interleukin-1 beta in patients with Crohn's disease and ulcerative colitis: preoperative levels and postoperative changes of serum concentrations.

Crohn's disease (CD) and ulcerative colitis (UC) show an intestinal activation of T cells and macrophages within the inflamed lesions. The aim of the present prospective study was to determine whether circulating interleukins (IL) represent useful markers of immune activation in vivo and to characterize their respective roles in monitoring disease activity. Serum concentrations of the soluble IL-2 receptor (sIL-2R), IL-6 and IL-1 beta were measured in 10 patients with CD and 10 patients with UC before, at day 10 and 2 years after resection of inflamed bowel segments. The data were correlated with neopterin, C-reactive protein and other standard parameters of disease activity. Preoperatively, mean sIL-2R concentration was 495 +/- 62 U/ml (mean +/- SEM; healthy controls; 210 +/- 25 U/ml; p less than 0.02) in CD and 705 +/- 120 U/ml (p less than 0.00002) in UC. The corresponding IL-6 serum concentrations were 37 +/- 6 U/ml in CD (controls: 11 +/- 0.6 U/ml; p less than 0.0036) and 33 +/- 6 U/ml (p less than 0.04) in UC. Two years postoperatively, sIL-2R was still elevated in 6 out of 9 patients in both disease groups. These patients did not differ from the remaining group with respect to disease activity. Serum IL-6, elevated in 7 patients with CD and in 6 patients with UC at day 10 postoperatively, had returned to normal in all patients by this time.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Down-regulation of protein kinase C activation in human lamina propria T lymphocytes: influence of intestinal mucosa on T cell reactivity.

Human lamina propria T lymphocytes (LPL-T) were shown to have lower proliferative responses to CD3 triggering than autologous peripheral blood T lymphocytes (PBL-T), yet preserved their responsiveness to CD2 stimulation. In order to elucidate the basis of these differences, freshly recovered human LPL-T and autologous PBL-T were stimulated with CD2 monoclonal antibodies anti-T11(2/3) plus sheep red blood cells and phorbol 12,13-dibutyrate (PBu2) plus ionomycin, respectively. LPL-T showed invariably lower responses to PBu2 plus ionomycin than PBL-T. In contrast, LPL-T still preserved proliferation to CD2 activation even when their responses to PBu2 plus ionomycin were decreased almost to background levels. Preincubation of PBL-T with intestinal mucosa supernatant led to a similar reactivity as observed in fresh LPL-T. Moreover, the protein kinase C (PKC) inhibitor sphinganine was able to inhibit DNA synthesis to stimulation with PBu2 plus ionomycin but not to CD2 triggering. This study suggests that CD2-induced proliferation is not dependent on PKC activation and that down-regulation of PKC activation may be one of the mechanisms for inhibition of the CD3-Ti-dependent activation pathway in LPL-T by intestinal mucosa-derived influences in vivo.

Antigens↗
PubMed1991

Mononuclear cells in peripheral venous blood of patients with Crohn's disease: preoperative status and postoperative course, influence of duration, activity and extent of disease.

In Crohn's disease (CD) the intestinal lesion is supposed to be the cause of the observed systemic immunologic changes. Based on this assumption, peripheral blood mononuclear cells (PBMC) are of specific interest as a possible indicator of intestinal activity of the disease. From 151 surgical patients CD3+, CD4+, CD8+, B cells, macrophages, leucocytes and the relative number of lymphocytes were analysed preoperatively and 10 days, 3 and 6 months postoperatively. The cell data were correlated with the main clinical data of disease. There was a highly significant preoperative increase of leucocytes, macrophages, CD8+, and B cells in the CD group, and a marked decrease of CD3+, CD4+ cells, and the relative lymphocyte count in the same group. Six months postoperatively, highly elevated macrophages, and leucocytes, and a depressed number of CD4+ cells were the only changes. The preoperative cell data did not correlate with the duration of illness, CDAI, localisation, and extent of the intestinal lesion nor did they correlate with any modality of preoperative drug treatment. Thus, the determination of PBMC characteristics in CD is only of limited value for routine diagnostic purposes. However, the persistence of some pathological values long after operation might be caused by residual microscopic lesions and thus reflect the intestinal process.

Adolescent↗