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Biomedical subjects

T Becker

Publications and source records attributed to T Becker.

At least 55 records · Page 3Linked to original sources
PubMed2003

[Surgical treatment for hilar cholangiocarcinoma (Klatskin's tumor)].

Surgical treatment of hilar bile duct carcinoma remains difficult, which is due to the inadequate possibilities in assessing tumor extent during the preoperative diagnostic procedure as well as intraoperatively. Radical resection with negative histologic margins offers the best chance for long-term survival. The decision regarding the appropriate surgical approach is challenging due to the complexity of tumor localization and neighboring vascular structures. Aggressive resection demands extended liver resection, which is associated with the risk of postoperative liver failure. However, even limited surgery such as hilar resection can be curative and leads to long-term survival in individual cases. The principles of surgical oncology have led to more aggressive procedures, including the combination of liver transplantation and multivisceral resection, and can be performed with calculable morbidity and mortality. Nevertheless, the high risk of tumor recurrence under long-term immunosuppression, the limited availability of donor organs and the excellent results of liver transplantation in non-malignant diseases do not justify this procedure at present. Neoadjuvant radiochemotherapy has failed to demonstrate major benefit. In patients with irresectable tumor or distant metastases palliative measures are aimed at restoring an unobstructed bile flow with endoscopic placement of metal stents. Palliative treatment with additional radio- or photodynamic therapy may be considered in individual cases.

Adult↗
PubMed2003

[Angiodysplasia of the colon combined with portal hypertension and recurrent gastrointestinal bleeding].

Angiodysplasia of the colon has been reported as one of the most common sources of lower gastrointestinal bleeding in the elderly whereas it is very rare in younger patients. Apart from this, portal hypertension may also have effects on the colon. There are, however, only a few reports which have investigated the colon in patients with portal hypertension. We report the case of a 16-year-old woman who presented massive bleeding from angiodysplasia of the colon assembled together with portal hypertension due to portal vein thrombosis caused presumably by neonatal umbilical cord infection. In this regard we discuss diagnosis, therapy and prognosis of this disease.

Adolescent↗
PubMed2002

Intrinsic inhomogeneities in manganite thin films investigated with scanning tunneling spectroscopy.

Thin films of La0.7Sr0.3MnO3 on MgO show a metal insulator transition and colossal magnetoresistance. The shape of this transition can be explained by intrinsic spatial inhomogeneities, which give rise to a domain structure of conducting and insulating domains at the submicrometer scale. These domains then undergo a percolation transition. The tunneling conductance and tunneling gap measured by scanning tunneling spectroscopy were used to distinguish and visualize these domains.

Journal Article↗
PubMed2002

Optimizing high strength acetic acid bioprocess by cognitive methods in an unsteady state cultivation.

Methods of adapting micro-organisms to an inhibiting factor in an active industrial bioprocess were examined with an acetic acid fermentation as model. With the aim of automatic control, a fuzzy-logic system was developed on the basis of the collected knowledge of skilled vinegar brewers. In a first step, this fuzzy system was to assess the actual adaptation degree of the bacteria on the basis of data from robust and reasonably priced sensors. From this information an appropriate setpoint value for the inhibiting factor 'final acid concentration' was derived for each batch cycle. As a result a further acid tolerance was found after several batch cycles. This adaptation effect should be used to increase the product concentration to more than 20 g per 100 ml acetic acid with a high productivity. The stepwise adapted culture was productive over the aimed acetic acid concentration, a 10% improvement of the product formation rate could be found compared with the status before conditioning. High product concentration and increased productivity finally result in shorter cycle times, less transport and storage volumes, an improved utilization of energy and material resources, and, last but not least, they are an essential steps towards the fulfillment of economical and ecological demands.

Acetic Acid↗
PubMed2002

Successful outcome of acute graft-versus-host disease in a liver allograft recipient by withdrawal of immunosuppression.

BACKGROUND: Graft-versus-host disease (GVHD) after liver transplantation is uncommon, and the outcome is almost always fatal. Since 1987, about 30 cases have been described, and patient survival is mostly exceptional. METHODS: A 29-year-old man underwent retransplantation due to chronic cholestatic syndrome, 5 years after his first liver transplantation. Indication for the first liver transplantation was acute liver failure caused by exsiccosis. After the second transplantation, the patient had an initially uneventful course, developing thrombocytopenia at day 21 followed by skin rash and septic complications. Diagnosis of acute GVHD was made by using serological techniques for HLA-A and HLA-DRB and subsequently by fluorogenic sequence-specific primed polymerase chain reaction. In addition, donor lymphocytes were marked by immunohistochemical methods via biopsies of the skin. Immunosuppressive therapy was withdrawn to allow the patient's own immune system to eliminate donor cells. RESULTS: By withdrawing the immunosuppressive therapy, clinical and morphological signs of GVHD vanished. The patient is doing well without recurrence 13 months after transplantation. CONCLUSION: Withdrawal of immunosuppressive therapy is a promising approach in the treatment of acute GVHD to allow the patient's immune system to reconstitute itself, reject offending lymphocytes, and avoid lethal septic complications.

Acute Disease↗
PubMed2002

[Neuroendocrine tumors of the stomach. Surgery therapy and prognosis].

Gastric carcinoid tumors are rare lesions characterized by hypergastrinemia that arise from enterochromaffin-like (ECL) cells of the stomach. A classification system distinguishing three types of gastric carcinoid tumors has been proposed: 1) tumors related to chronic atrophic gastritis, 2) tumors associated with Zollinger-Ellison syndrome, and 3) sporadic lesions. It is apparent that hypergastrinemia-associated gastric carcinoids show a rather benign biological behavior. Normo-gastrinemic sporadic lesions, on the other hand, require an aggressive surgical management. We report seven patients with gastric neuroendocrine tumors ("carcinoids"), who underwent surgical treatment in our department between 1988 and 2000. Surgical therapy included total gastrectomy with D2 lymphadenectomy in two cases with type I tumors and for one patient with type III tumor. One patient with a type II tumor was treated by distal subtotal gastrectomy and another by antrectomy. A local excision was performed on one patient with type I tumor. After a mean follow-up of 8 years, 5 of 7 patients are alive without recurrence.

Adult↗
PubMed2002

Provision of services for people with schizophrenia in five European regions.

BACKGROUND: An increasing diversity of public, voluntary sector and private providers offer services for the mentally ill in the ongoing process of psychiatric reform. Good service description is one important prerequisite for mental health service research. Aims 1) To describe service provision for the mentally ill in five European centres using the European Service Mapping Schedule (ESMS); and 2) to discuss the use of the instrument in describing service provision. METHODS: All services providing care for people with severe mental illness in five European catchment areas (in Amsterdam, the Netherlands; Copenhagen, Denmark; London, UK; Santander, Spain; Verona, Italy) were identified through various sources. The identified services were classified, and service provision was quantified in accordance with the ESMS manual. Descriptive information was obtained. RESULTS: We identified from 10 to 45 different services for catchment areas of between 50,000 (Copenhagen) and 560,000 (Santander) population run by three to 16 providers. They varied in aims, staffing and functioning. Hospital and non-hospital residential services, community-based services, and social support agencies were available in all sites. There was substantial variation across centres in the range, number and activities of services. Collecting comparable data sets on all service types, particularly for day and structured activity services and outpatient and community services required substantial effort. CONCLUSION: Operationalised description of mental health services across Europe is possible but requires further refinement.

Adolescent↗
PubMed2002

Quality of life in patients with schizophrenia in five European countries: the EPSILON study.

OBJECTIVE: To compare subjective quality of life (QOL) and objective QOL indicators in patients with schizophrenia from five European sites: Amsterdam, Copenhagen, London, Santander and Verona. METHOD: A representative sample of 404 patients with schizophrenia, in contact with mental health services, was randomly selected and evaluated with the Lancashire Quality of Life Profile (EU). RESULTS: The level of satisfaction in certain domains, religion, family and social relations appears to be associated with local style of living and culture while work, finances, and safety were more independent from local variations. In addition to the severity of symptoms, frequency of contacts with family, friendship and age appear as predictors of QOL, all of them influenced by the characteristics of the surroundings. CONCLUSION: The centres participating in the study presented differences in subjective measures of QOL, objective indicators and also in service provision and styles of living.

Adult↗
PubMed2002

[Comparison between treatment results for gastric cancer in younger and elderly patients].

INTRODUCTION: While gastric cancer shows an increased incidence in elderly patients, the rate of younger patients affected by this disease represents up to 15 %. Younger patients are frequently diagnosed with advanced tumor stages with a poor prognosis although literature data on this issue are controversial. PATIENTS AND METHODS: 643 patients with primary gastric carcinoma were operated in our institution between March 1986 and December 2000. No neoadjuvant treatment was administered in these patients. We analysed the data of these patients retrospectively. A comparison of the results between patients younger than 40 years (n = 38, median age 37 years) and older than 70 years (n = 182, median age 75 years) was performed. RESULTS: The radical (R0-) resectability rate was rather high for both, younger (78.9 %) and elderly (76.9 %) patients. Postoperative morbidity was higher in elderly than in younger patients (32.9 % vs. 23.2 %; p < 0.05), as well as the postoperative mortality (7.7 % vs. 2.6 %; p < 0.05). Both younger and elderly patients showed advanced (II to IV) tumor stages (76.3 % vs. 73.3 %, n. s.). There was a significant difference between the rate of diffuse carcinomas in young and elderly patients (63.2 % vs. 22.5 %). The 5-years survival rate following R0-resection was significantly higher for younger patients (54.2 % vs. 32.9 %; p = 0.01), differences occurred only after the second postoperative year. CONCLUSIONS: The resectability of gastric carcinoma is not related to the patients age. Due to comorbidity, postoperative morbidity may be increased in elderly patients. Although both younger and elderly patients show advanced tumor stages, diffuse carcinomas are more frequent in younger patients. The short-term prognosis is similar for both age groups, long-term results are better for younger patients. The different life expectancy should be considered when interpreting these results.

Adult↗
PubMed2002

The relationship of fetal eye movements to non-stress test results.

OBJECTIVE: This study was designed to correlate ultrasound-observed fetal eye movements with fetal heart rate reactivity to determine its potential role in fetuses with persistent non-reactivity. METHODS: A total of 104 non-stress tests (NSTs) were evaluated in 62 patients referred for fetal surveillance for standard antepartum indications. Ultrasound-observed eye movements, assessed during portions of these NSTs, were categorized as negative (0), intermittent (1-5/min), or rapid (> or = 6/min). RESULTS: Of the NSTs, 97 were reactive and seven were non-reactive. All studied fetuses were apparently healthy, as the seven patients with persistently non-reactive NSTs had biophysical profile scores of 8/10. During the NSTs, 120 reactive portions and 81 non-reactive portions were evaluated for ultrasound-observed eye movements. During reactive portions, eye movements were negative 19% of the time, intermittent 24% of the time and rapid 56% of the time. During non-reactive portions, eye movements were negative 84% of the time, intermittent 7.8% of the time and rapid 7.8% of the time. All fetuses demonstrating eye movements during non-reactive periods became reactive shortly thereafter, and all of the seven persistently non-reactive fetuses displayed negative ultrasound-observed eye movements throughout the entire observation period. CONCLUSIONS: Healthy fetuses display a strong relationship between non-reactive heart rate tracings and absent or diminished eye movements, consistent with quiet sleep. Conversely, reactive periods are associated with a high incidence of rapid eye movement. Further study is needed in fetuses documented to be hypoxic.

Cardiotocography↗
PubMed2001

Risk factors for the presence of varices in cirrhotic patients without a history of variceal hemorrhage.

BACKGROUND: Current medical management dictates that all cirrhotic patients without a history of variceal hemorrhage undergo endoscopic screening to detect large varices. However, referral for endoscopic screening of only patients at highest risk for varices may be most cost-effective. The aim of this case-control study was to identify clinical, laboratory, and radiologic findings that predict the presence of varices in patients with cirrhosis. METHODS: Three hundred patients without a history of variceal hemorrhage underwent upper endoscopy as part of an evaluation before liver transplantation. Cases defined as the presence of any varices and cases defined as the presence of large varices were used for examining the risks associated with finding varices on upper endoscopy. Logistic regression was performed to evaluate associations between the presence of varices and patient characteristics. RESULTS: Platelet count and Child-Pugh class were independent risk factors for the presence of any varices and the presence of large varices. For the presence of any varices, a platelet count of 90 x 10(3)/microL or less (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.4-4.0) and advanced Child-Pugh class (OR, 3.0; 95% CI, 1.6-5.6) were independent risk factors. For large varices, a platelet count of 80 x 10(3)/microL or less (OR, 2.3; 95% CI, 1.4-3.9) and advanced Child-Pugh class (OR, 2.8; 95% CI, 1.3-5.8) were independent risk factors associated with varices. CONCLUSIONS: Low platelet count and advanced Child-Pugh class were associated with the presence of any varices and with large varices. These factors allow identification of a subgroup of cirrhotic patients who would benefit most from referral for endoscopic screening for varices.

Adult↗
PubMed2001

The structure of the coliphage HK022 Nun protein-lambda-phage boxB RNA complex. Implications for the mechanism of transcription termination.

Nun protein from coliphage HK022 binds to phage boxB RNA and functions, in contrast to phage lambda N protein, as a transcriptional terminator. The basic Nun-(10-44) peptide contains the boxB RNA binding arginine rich motif, ARM. The peptide binds boxB RNA and competes with the phage lambda ARM peptide N-(1-36) as indicated by nuclear magnetic resonance (NMR) spectroscopy titrations. In two-dimensional nuclear Overhauser enhancement spectroscopy experiments boxB RNA in complex with Nun-(20-44) exhibits the same pattern of resonances as it does in complex with N peptides containing the ARM, and we could show that Nun-(20-44) forms a bent alpha-helix upon binding to the boxB RNA. The structure of the boxB RNA-bound Nun-(20-44) was determined on the basis of 191 intra- and 30 intermolecular distance restraints. Ser-24 is anchored to the lower RNA stem, and stacking of Tyr-39 and A7 is clearly experimentally indicated. Arg-28 shows numerous contacts to the RNA stem. Leu-22, Ile-30, Trp-33, Ile-37, and Leu-41 form a hydrophobic surface, which could be a recognition site for additional host factors such as NusG. Such a hydrophobic surface area is not present in N-(1-36) bound to boxB RNA.

Amino Acid Sequence↗
PubMed2001

Regenerating descending axons preferentially reroute to the gray matter in the presence of a general macrophage/microglial reaction caudal to a spinal transection in adult zebrafish.

We analyzed pathway choices of regenerating, mostly supraspinal, descending axons in the spinal cord of adult zebrafish and the cellular changes in the spinal cord caudal to a lesion site after complete spinal transection. Anterograde tracing (by application of the tracer rostral to the spinal lesion site) showed that significantly more descending axons (74%) regenerated in the spinal gray matter of the caudal spinal cord than would be expected from random growth. Retrograde tracing (by application of the tracer caudal to the spinal lesion site) showed that, rostral to the lesion, most of these axons (80%) extended into the major white matter tracts. Thus, ventral descending tracts often were devoid of labeled axons caudal to a spinal lesion but contained many axons rostral to the lesion in the same animals, indicating a pathway switch of descending axons from the white matter to the gray matter. Ascending axons of spinal neurons were not observed regrowing to the rostral tracer application site; therefore, they most likely did not contribute to the axonal populations analyzed. A macrophage/microglia response within 2 days of spinal cord transection, along with phagocytosis of myelin, was observed caudal to the transection by immunohistochemistry and electron microscopy. Nevertheless, caudal to the lesion, descending tracts in the white matter were filled with myelin debris during the time of axonal regrowth, at least up to 6 weeks postlesion. We suggest that the spontaneous regeneration of axons of supraspinal origin after spinal cord transection in adult zebrafish may be due in part to the axons' ability to negotiate novel pathways in the spinal cord gray matter.

Age Factors↗
PubMed2001

Differentiation of liver cell adenomas from well-differentiated hepatocellular carcinomas by comparative genomic hybridization.

Liver cell adenomas (LCAs) are rare tumours which may be difficult to differentiate from low-grade hepatocellular carcinomas (HCCs). This study used comparative genomic hybridization (CGH) to look for cytogenetic aberrations which would serve to distinguish between these tumours. For this purpose, ten LCAs and six well-differentiated HCCs were analysed and the results were compared with those reported previously for 15 well-differentiated HCCs. Aberrations were seen in 2/10 LCAs: a gain of chromosome 7p was observed in one and gains of 17q and 20 in a second case. In 6/6 well-differentiated HCCs, up to 13 aberrations were detectable, with a mean of 7.2 aberrations per case in chromosome sites 1q, 4p, 4q, 5p, 5q, 6p, 6q, 7p, 7q, 8p, 8q, 10q, 11p, 13q, 14q, 16p, 16q, 17p, 17q, 20p, 20q, and 21q. Aberrations focused on gains or losses of six chromosome sites, 1q, 4q, 8p, 8q, 16p, and 17p; in all HCC samples, at least two of these sites were affected. None of these aberrations occurred in any of the LCAs analysed. CGH is therefore helpful in distinguishing between LCA and well-differentiated HCC. Detection of one or more of the six most frequent aberrations in HCC supports the diagnosis of carcinoma and makes LCA unlikely.

Adenoma, Liver Cell↗
PubMed2001

Increased NCAM-180 immunoreactivity and maintenance of L1 immunoreactivity in injured optic fibers of adult mice.

The injury related expression of two axon-growth promoting cell adhesion molecules (CAMs), NCAM-180 which is developmentally downregulated and L1 which is regionally restricted, were compared in optic fibers in the adult mouse. The neuron-specific isoform of NCAM (NCAM-180) is present at very low levels in unlesioned adult optic axons. At 7 days after nerve crush, immunoreactivity was strongly and uniformly increased in optic axons within the nerve and throughout retina. Reactivity in surviving axons had returned to control levels at 4 weeks. To induce regrowth of adult retinal ganglion cell axons retinal explants were placed in culture. Strong NCAM-180 staining was observed on these regenerating optic axons. The neuronal cell adhesion molecule L1 is restricted to retina and to the unmyelinated segment of the optic nerve near the optic nerve head in unlesioned adult animals. Following nerve crush, L1 immunoreactivity was retained within retina and proximal nerve and novel staining was detected in the more distal segment of the optic nerve up to the lesion site where it persisted for at least eight months. The capacity of optic fibers to show increased NCAM-180 immunoreactivity and maintain L1 expression after a lesion may explain why these fibers exhibit relatively good potential for regeneration.

Animals↗
PubMed2001

Antibody to the HNK-1 glycoepitope affects fasciculation and axonal pathfinding in the developing posterior lateral line nerve of embryonic zebrafish.

The HNK-1 glycoepitope, carried by many cell recognition molecules, is present in the developing posterior lateral line nerve and on other primary axons of zebrafish. To elucidate the function of HNK-1 in vivo, the antibody 412 to HNK-1 was injected into zebrafish embryos at 16 h post fertilization (hpf). The injected antibody bound specifically to axons carrying HNK-1. This treatment selectively affected the growth of either one or both posterior lateral line nerves in 39% of the experimental cases (13 of 33 animals), which was significantly more (P<0.0002) than in uninjected, vehicle injected, and non-immune IgG injected controls (1.2% of the animals; one of 85 animals), as assessed at 27 or 33 hpf. Other HNK-1 immunoreactive nerves, such as the ventral motor nerves were unaffected, indicating that antibody binding per se did not interfere with axon growth. The primordium of the posterior lateral line was not affected in its caudal migration and in depositing differentiating neuromasts along the trunk, showing that injections did not retard development and that initial formation of lateral line organs is probably independent of contact with nerve fibers. We suggest that the HNK-1 glycoepitope is an important modulator of embryonic nerve growth.

Animals↗