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Biomedical subjects

J Köhler

Publications and source records attributed to J Köhler.

At least 19 recordsLinked to original sources
PubMed2007

[Applicability, duration, and sociomedical course of rehabilitation of alcohol dependency. Current results and perspectives from the insurers' point of view].

Reducing the paucity of German studies on the rehabilitation of alcohol-dependent patients, this article presents current data of Germany's national Pension Insurance Federal Institution. Numbers of applications, grants and use of rehabilitation, length and duration of treatment, percentage of nonattendance, comorbidity, and sociomedical course after 2 years are discussed. There has been a constant increase in numbers of rehabilitative treatment, especially in the outpatient setting with decreased treatment length, a high rate of comorbidity, and improvements in the sociomedical course and vocational integration. Two years after rehabilitation, 87% of inpatients and 92% of outpatients were recontributing to the pension system continuously or sporadically. Despite the still marked deficits in the provision of rehabilitative treatment for addicted patients, rehabilitation plays an important and established role in this field and shows promising clinical results.

Adult↗
PubMed2006

[The effectiveness of psychosocial treatment approaches for alcohol dependence--a review].

Treatment approaches which are used in the context of inpatient alcoholism treatment are frequently neither theoretically justified nor empirically examined. In view of the enormous method variety the necessity exists for the development of treatment guidelines in order to offer indicators of promising treatment achievement for practitioners and pension funds. In a first step, it must be examined which treatments are effective, which are ineffective and which are possibly even counter-productive. This article aims to give a comprehensive review of randomized-controlled studies/meta-analysis on the efficacy of different treatment approaches. This article reporting the literature review is part of a larger programme to develop clinical practice guidelines for rehabilitation which is supported in form, content and finance by the German Pension Institute for Salaried Employees (Bundesversicherungsanstalt für Angestellte, BfA). Summing up, treatment is effective compared to no treatment. Cognitive behavioural therapy included in a multimodal treatment program is effective. There are a number of treatment protocols for which controlled research has consistently found positive results like social skills training, community reinforcement approaches, behaviour contracting, motivation-enhancing treatment, and family/marital therapy. There is also a number of commonly used treatment approaches that brought neither a positive result or were counter productive like relapse prevention, non-behavioural marital therapy, and insight psychotherapy, confrontational counseling, education, relaxation training, and milieu therapy. Support for matching to a specific treatment is weak, but interventions against alcohol problems should be differentiated according to the severity of the alcohol problem. Since treatment evaluation is mainly accomplished in the US and supplying structures with respect to the US and Germany are substantially different, a generalized transmission of US-American research results on Germany is to be evaluated carefully. Randomized-controlled studies are needed in Germany.

Alcoholism↗
PubMed2006

Epifluorescence, confocal and total internal reflection microscopy for single-molecule experiments: a quantitative comparison.

Epifluorescence, confocal and total internal reflection microscopy are the most widely used techniques for optical single-molecule experiments. Employing these methods, we recorded the emission intensity of the same single molecule as a function of the excitation rate under otherwise identical experimental conditions. Evaluation of these data provides a quantitative comparison of the signal-to-background ratios that can be achieved for the three microscopic techniques.

Journal Article↗
PubMed2003

[Carcinoma of the pancreas head, papilla Vateri, and cystadenocarcinoma--different biologic entities and different results].

Between 1986-1995 we operated 337 patients with ductal adenocarcinoma of the pancreas, 45 cases of carcinoma of the papilla of Vater and 11 patients with cystadenocarcinoma of the pancreas. The evaluation of prognostic factors showed the influence of lymph node invasion. Furthermore we saw a significant influence of lymph- and haemangiosis carcinomatosa, of tumor-grading and tumor-size. The carcinoma of the papilla showed a better 5-year survival even in nodal-positive patients--this as a result of a different biological behaviour. We think that--instead of missing improvement of cure in ductal adenocarcinoma over the past decade--there is no place for therapeutic nihilism especially in non-ductal cancer, which represents almost 15 % of all pancreatic neoplasms.

Aged↗
PubMed2002

[Subarachnoid hemorrhage without aneurysm].

The rupture and bleeding of intracranial aneurysms is the most common cause of a spontaneous, non-traumatic subarachnoid hemorrhage (SAH). In up to 20% of these patients, no aneurysm is found, but the prognosis of these patients is known to be better than in those with aneurysms. The retrospective evaluation of the initial CT- and angiographic findings of 773 patients with spontaneous SAH, who underwent (up to three) 4-vessel DSA, brought a percentage of 12.4% with negative angiography. We found the favourable prognosis of these patients with negative angiography not only to be dependent from the distribution of the hemorrhage, with preference to perimesencephalic pattern, but the initial clinical state. 85% of our patients, who presented with perimesencephalic blood pattern and even 80% of those patients with additional intraventricular hemorrhage but the good clinical condition of Hunt-Hess I/II were discharged without neurological deficits. We recommend the obligatory 4-vessel catheter-angiography (DSA) in all patients with spontaneous SAH, independent of the blood pattern on initial CT, and one control in the presence of other than perimesencephalic subarachnoid hemorrhage, CTA might be reserved for additional controls.

Adult↗
PubMed2002

[Cystic pancreatic tumors--differential diagnosis, surgical therapy. Prognosis of cystic pancreatic tumors].

From 1986-2001 we treated 31 patients with cystic neoplasms of the pancreas. 13 patients showed a cystadenocarcinoma including one rare case of a serous cystadenocarcinoma. A curative resection (R0) was possible in 10 patients (resection rate: 76.9%). After median 61 months (range 29-144 months) 8 patients are alive without evidence of tumour. 2 patients died 2 months (pneumonia) and 36 months (local recurrence) respectively after operation. The latter case of tumour recurrence showed nodal involvement (pN1) in the Whipple specimen. One patient died 44 months after Whipple procedure with tumour-positive resection margin (R1 Situation) from local recurrence and hepatic spread. Our data reflect the good prognosis of cystic neoplasms of the pancreas reported in literature after curative resection--a result of the different biological behaviour compared with ductal adenocarcinome.

Adenocarcinoma↗
PubMed2001

Recruitment of cortexillin into the cleavage furrow is controlled by Rac1 and IQGAP-related proteins.

Cytokinesis in eukaryotic organisms is under the control of small GTP-binding proteins, although the underlying molecular mechanisms are not fully understood. Cortexillins are actin-binding proteins whose activity is crucial for cytokinesis in Dictyostelium. Here we show that the IQGAP-related and Rac1-binding protein DGAP1 specifically interacts with the C-terminal, actin-bundling domain of cortexillin I. Like cortexillin I, DGAP1 is enriched in the cortex of interphase cells and translocates to the cleavage furrow during cytokinesis. The activated form of the small GTPase Rac1A recruits DGAP1 into a quaternary complex with cortexillin I and II. In DGAP1(-) mutants, a complex can still be formed with a second IQGAP-related protein, GAPA. The simultaneous elimination of DGAP1 and GAPA, however, prevents complex formation and localization of the cortexillins to the cleavage furrow. This leads to a severe defect in cytokinesis, which is similar to that found in cortexillin I/II double-null mutants. Our observations define a novel and functionally significant signaling pathway that is required for cytokinesis.

Amino Acid Sequence↗
PubMed2001

Dynamics of the Dictyostelium Arp2/3 complex in endocytosis, cytokinesis, and chemotaxis.

The Arp2/3 complex is a ubiquitous and important regulator of the actin cytoskeleton. Here we identify this complex from Dictyostelium and investigate its dynamics in live cells. The predicted sequences of the subunits show a strong homology to the members of the mammalian complex, with the larger subunits generally better conserved than the smaller ones. In the highly motile cells of Dictyostelium, the Arp2/3 complex is rapidly re-distributed to the cytoskeleton in response to external stimuli. Fusions of Arp3 and p41-Arc with GFP reveal that in phagocytosis, macropinocytosis, and chemotaxis the complex is recruited within seconds to sites where actin polymerization is induced. In contrast, there is little or no localization to the cleavage furrow during cytokinesis. Rather the Arp2/3 complex is enriched in ruffles at the polar regions of mitotic cells, which suggests a role in actin polymerization in these ruffles.

Actin-Related Protein 2↗
PubMed2001

Optical spectroscopy of individual objects.

With the introduction of single-molecule spectroscopy it was immediately realised that studying molecules and molecular aggregates individually opens up a completely new approach to elucidate information commonly washed out by the ensemble average process. In contrast with ensemble experiments, this technique permits us to determine the whole distribution of parameters rather than their moments. This allows a more direct verification of theoretical models without the need to average over (unknown) distributions to calculate observables. Here we illustrate how single-molecule spectroscopy can be utilised to circumvent the classical diffraction limit of microscopy and show an investigation of the electronic structure of pigment protein complexes that are relevant for bacterial photosynthesis.

Adenosine Triphosphate↗
PubMed2001

Spectroscopy on the B850 band of individual light-harvesting 2 complexes of Rhodopseudomonas acidophila. I. Experiments and Monte Carlo simulations.

The electronic structure of the circular aggregate of 18 bacteriochlorophyll a (BChl a) molecules responsible for the B850 absorption band of the light-harvesting 2 (LH2) complex of the photosynthetic purple bacterium Rhodopseudomonas acidophila has been studied by measuring fluorescence-excitation spectra of individual complexes at 1.2 K. The spectra reveal several well-resolved bands that are obscured in the single, broad B850 band observed in conventional absorption measurements on bulk samples. They are interpreted consistently in terms of the exciton model for the circular aggregate of BChl a molecules. From the energy separation between the different exciton transitions a reliable value of the intermolecular interaction is obtained. The spectra of the individual complexes allow for a distinction between the intra- and the intercomplex disorder. In addition to the random disorder, a regular modulation of the interaction has to be assumed to account for all the features of the observed spectra. This modulation has a C(2) symmetry, which strongly suggests a structural deformation of the ring into an ellipse.

Bacterial Proteins↗
PubMed2001

Spectroscopy on the B850 band of individual light-harvesting 2 complexes of Rhodopseudomonas acidophila. II. Exciton states of an elliptically deformed ring aggregate.

Spectroscopy of individual light-harvesting 2 complexes from purple photosynthetic bacteria revealed a deformation of the circular complex into C(2) symmetry. The present work relates the geometry of the deformed aggregate to its spectroscopic properties. Different models of elliptical deformation are discussed and compared with the experimental findings. It is shown that the model with smaller interpigment distances, where the curvature of the ellipse is small, provides the best agreement with fluorescence excitation spectra of individual complexes.

Bacterial Proteins↗
PubMed2001

Long-term follow-up of reflux nephropathy in adults with vesicoureteral reflux--radiological and pathoanatomical analysis.

PURPOSE: To study the long-term development of urographic renal morphology in adults with vesicoureteral reflux, to investigate the relationship between renal damage and reflux grade, and to analyse the association between the long-term urographic outcome and the occurrence of acute pyelonephritis and reflux during follow-up. The purpose was also to try to distinguish between acquired and developmental renal damage, based on analyses of renal histological specimens and urographic features, and to analyse associated congenital urogenital abnormalities and family history of reflux, reflux nephropathy, urological malformation or death from end-stage renal disease. MATERIAL AND METHODS: Renal damage was identified in 100 (83 women) of 115 adults, selected because of documented reflux. Eighty-seven patients had two urographies done (median interval 14.3 years). The extent and progression of renal damage were assessed and features of developmental renal damage were determined. Histological renal specimens were available in 23 patients with renal damage. RESULTS AND CONCLUSIONS: The extent of renal damage correlated positively with the severity of reflux. No renal damage developed during the follow-up in 45 previously undamaged kidneys and progression of renal damage was rare (4 of 120 previously damaged kidneys), despite persisting reflux in half of the cases and episodes of acute pyelonephritis during follow-up. Thus, repeated renal imaging is rarely justified in adults with reflux nephropathy. Histological examination showed "chronic pyelonephritis" in all 23 cases and co-existing renal dysplasia in 1 case. The detailed urographic analysis did not reveal support for developmental renal damage. High frequencies of associated congenital urogenital abnormalities and of a positive family history were found. Thus, congenital and/or hereditary factors cannot be discarded as background factors for the development of renal damage.

Acute Disease↗
PubMed2001

Conservative treatment and anti-reflux surgery in adults with vesico-ureteral reflux: effect on urinary-tract infections, renal function and loin pain in a long-term follow-up study.

STUDY PURPOSE: To investigate the long-term effects in adults of conservative treatment and anti-reflux surgery for vesico-ureteral reflux on urinary-tract infections, renal function, and loin pain. METHODS: Of 115 adult patients with vesico-ureteral reflux diagnosed between 1968 and 1984, conservative treatment was given to 46 patients (36 women) and anti-reflux surgery was performed in 57 patients (52 women). The remaining 12 patients underwent nephrectomy or heminephrectomy and were excluded from the study. The anti-reflux surgical methods used were the Politano-Leadbetter procedure in 44 patients (73 ureters) and the Hutch procedure in 19 patients (25 ureters). Six of these patients were operated on with both methods. RESULTS: The frequency of acute pyelonephritis was significantly reduced after anti-reflux surgery (P < 0.0001) as well as after diagnosis of vesico-ureteral reflux in the group given conservative treatment (P or < 0.001). The frequency of lower-urinary-tract infections was not altered in either group. Surgery had no effect on significant albuminuria (Albustix > or = 2+) or on progressive renal functional deterioration. Forty-three patients reported recurrent loin pain at the time of diagnosis or anti-reflux surgery. Only one of the 12 patients in the conservative group, compared with 29 of the 31 patients in the anti-reflux surgery group, obtained relief from loin pain during the follow-up. Nine patients in the anti-reflux surgery group reported restitution of reduced general well-being after surgery. These patients had experienced weariness and/or headache before surgery. Vesico-ureteral reflux was eliminated more frequently (P < 0.01) in the patients operated on by the Politano-Leadbetter procedure (94%) than in those operated on by the Hutch procedure (68%). CONCLUSIONS: Loin pain is common in adults with vesico-ureteral reflux and is effectively eliminated by anti-reflux surgery. Anti-reflux surgery should be considered in adults with vesico-ureteral reflux and very frequent acute pyelonephritic attacks only if conservative treatment has failed to alleviate these symptoms. Anti-reflux surgery is not indicated with the aim of arresting renal functional deterioration.

Adolescent↗
PubMed2001

beta(3)A-integrin downregulates the urokinase-type plasminogen activator receptor (u-PAR) through a PEA3/ets transcriptional silencing element in the u-PAR promoter.

Migration of cells requires interactions with the extracellular matrix mediated, in part, by integrins, proteases, and their receptors. Previous studies have shown that beta(3)-integrin interacts with the urokinase-type plasminogen activator receptor (u-PAR) at the cell surface. Since integrins mediate signaling into the cell, the current study was undertaken to determine if in addition beta(3)-integrin regulates u-PAR expression. Overexpression of beta(3)-integrin in CHO cells, which are avid expressers of the receptor, downregulated u-PAR protein and mRNA expression. The u-PAR promoter (-1,469 bp) that is normally constitutively active in CHO cells was downregulated by induced beta(3)-integrin expression. A region between -398 and -197 bp of the u-PAR promoter was critical for beta(3)-integrin-induced downregulation of u-PAR promoter activity. Deletion of the PEA3/ets motif at -248 bp substantially impaired the ability of beta(3)-integrin to downregulate the u-PAR promoter, suggesting that the PEA3/ets site acts as a silencing element. An expression vector encoding the transcription factor PEA3 caused inhibition of the wild-type but not the PEA3/ets-deleted u-PAR promoter. The PEA3/ets site bound nuclear factors from CHO cells specifically, but binding was enhanced when beta(3)-integrin was overexpressed. A PEA3 antibody inhibited DNA-protein complex formation, indicating the presence of PEA3. Downregulation of the u-PAR promoter was achieved by the beta(3)A-integrin isoform but not by other beta(3)-integrin isoforms and required the cytoplasmic membrane NITY(759) motif. Moreover, overexpression of the short but not the long isoform of the beta(3)-integrin adapter protein beta(3)-endonexin blocked u-PAR promoter activity through the PEA3/ets binding site. Thus, besides the physical interaction of beta(3)-integrin and u-PAR at the cell surface, beta(3) signaling is implicated in the regulation of u-PAR gene transcription, suggesting a mutual regulation of adhesion and proteolysis receptors.

Amino Acid Sequence↗
PubMed2000

Taxonomy and palaeoecology of dinoflagellate cysts from Upper Oligocene freshwater sediments of Lake Enspel, Westerwald area, Germany.

Freshwater dinoflagellates play an important role as primary producers in the lacustrine environment. A new species of dinoflagellates, Cleistosphaeridium lacustre, is described from Upper Oligocene sediments of palaeo-lake Enspel. They are associated with other phytoplankton, such as diatoms, chrysophytes, green algae and benthic cyanobacteria. Mass occurrences of this species are interpreted as algal blooms and may partly reflect seasonal successions. This phenomenon was controlled by volcanic activities in the depositional area, which led to an increase in nutrient supply.

Journal Article↗
PubMed2000

[PtIn]

Explore the source record for details and available documents.

Journal Article↗
PubMed2000

Two-step positioning of a cleavage furrow by cortexillin and myosin II.

BACKGROUND: Myosin II, a conventional myosin, is dispensable for mitotic division in Dictyostelium if the cells are attached to a substrate, but is required when the cells are growing in suspension. Only a small fraction of myosin II-null cells fail to divide when attached to a substrate. Cortexillins are actin-bundling proteins that translocate to the midzone of mitotic cells and are important for the formation of a cleavage furrow, even in attached cells. Here, we investigated how myosin II and cortexillin I cooperate to determine the position of a cleavage furrow. RESULTS: Using a green fluorescent protein (GFP)-cortexillin I fusion protein as a marker for priming of a cleavage furrow, we found that positioning of a cleavage furrow occurred in two steps. In the first step, which was independent of myosin II and substrate, cortexillin I delineated a zone around the equatorial region of the cell. Myosin II then focused the cleavage furrow to the middle of this cortexillin I zone. If asymmetric cleavage in the absence of myosin II partitioned a cell into a binucleate and an anucleate portion, cell-surface ruffles were induced along the cleavage furrow, which led to movement of the anucleate portion along the connecting strand towards the binucleate one. CONCLUSIONS: In myosin II-null cells, cleavage furrow positioning occurs in two steps: priming of the furrow region and actual cleavage, which may proceed in the middle or at one border of the cortexillin ring. A control mechanism acting at late cytokinesis prevents cell division into an anucleate and a binucleate portion, causing a displaced furrow to regress if it becomes aberrantly located on top of polar microtubule asters.

Animals↗