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Biomedical subjects

I Becker

Publications and source records attributed to I Becker.

At least 19 recordsLinked to original sources
PubMed2007

Quantitative protein analysis from formalin-fixed tissues: implications for translational clinical research and nanoscale molecular diagnosis.

Owing to its cross-linking effects, it is currently believed that formalin fixation of routinely processed tissues in the clinic prevents protein extraction and profiling. The aim of our study was to develop a robust, fast, standardized, and easy to use technique for the solubilization of non-degraded, full length, and immunoreactive proteins from formalin-fixed tissues for western blot and protein microarray analysis. Sections of routinely processed formalin-fixed and paraffin-embedded tissues of various origin were analysed. After deparaffination, tissues were manually dissected from the slides and transferred into an optimized protein extraction buffer system. Proteins were solubilized and subsequently analysed by western blot and reverse phase protein microarrays. We succeeded in isolating non-degraded, soluble, and immunoreactive proteins from routinely processed formalin-fixed tissues. We were able to detect membrane, cytoplasmic and nuclear proteins at the expected molecular weight. No differences were found in the protein yield and protein abundances between fresh frozen and formalin-fixed tissues. Using western blots and reverse phase protein microarrays, the receptor tyrosine kinase HER2, an important protein target for antibody based cancer treatment, was reliably measured in formalin-fixed breast cancer biopsy samples when compared with measurement by immunohistochemistry and fluorescence in situ hybridization; remarkably, immunohistochemically equivocal cases (score 2+) can be categorized according to HER2 protein abundance. Our new clinically orientated multiplexed protein measurement system may be generally applicable to determine the relative abundances of known disease-related proteins in small amounts of routinely processed formalin-fixed tissue samples for research and diagnosis. This technique may also be used to identify, characterize, and validate known and new protein markers in a variety of human diseases.

Animals↗
PubMed2006

Leishmania major : detection of membrane-bound protein tyrosine phosphatase.

PTPases have been reported as a virulence factor in different pathogens. Recent studies suggest that PTPases play a role in the pathogenesis of Leishmania infections through activation of macrophage PTPases by the parasite. We report here the presence of a membrane-bound PTPase in Leishmania major promastigotes. We detected differences in the PTPases present in the procyclic and metacyclic stages of promastigotes. In metacyclic promastigotes, the PTPase activity was totally inhibited by specific PTPase and serine/threonine inhibitors, whereas in procyclic promastigotes the PTPase activity was inhibited only with PTPase inhibitors. Two antibodies against the catalytic domains of the human placental PTPase1B and a PTPase from Trypanosoma brucei cross-reacted with a 55-60 kDa molecule present in the soluble detergent-extracted fraction of a Leishmania homogenate. Metacyclic promastigotes expressed more of this molecule than parasites in the procyclic stage. Yet the specific activity of the enzyme was lower in metacyclic than in procyclic promastigotes. Ultrastructural localization of the enzyme showed that it was more membrane-associated in metacyclic promastigotes, whereas in procyclic promastigotes it was scattered throughout the cytoplasm. This is the first demonstration of a PTPase present in Leishmania major promastigotes that differs in expression, activity and ultrastructural localization between the procyclic and metacyclic stages of the parasite's life-cycle.

Acid Phosphatase↗
PubMed2005

Hereditary non-polyposis colorectal cancer: clinical and molecular evidence for a new entity of hereditary colorectal cancer.

BACKGROUND: Hereditary non-polyposis colorectal cancer (HNPCC) is clinically defined by familial clustering of colorectal cancer and other associated tumours. METHODS: By thorough molecular and clinical evaluation of 41 families, two different groups were characterised: group 1, 25 families with truncating mutations in MLH1 or MSH2 (12 novel mutations); and group 2, 16 Amsterdam positive families without mutations in these genes and without microsatellite instability in their corresponding tumours. RESULTS: Significant clinical differences between these two groups were found. Firstly, earlier age of onset for all colorectal cancers (median 41 v 55 years; p < 0.001) and all tumours (median 43 v 56 years; p = 0.022) was observed, comparing groups 1 and 2. Secondly, 68% of the index colorectal cancers were localised proximally of the splenic flexure in group 1 compared with 14% in group 2 (p < 0.010). Thirdly, more synchronous and metachronous colorectal (p = 0.017) and extracolorectal tumours (p < 0.001) were found in group 1. Fourthly, a higher colorectal adenoma/carcinoma ratio (p = 0.030) and a tendency towards more synchronous or metachronous adenomas in group 2 (p = 0.084) was observed, indicating a slower progression of adenomas to carcinomas. As three mutation negative tumours revealed chromosomal instability after comparative genomic hybridisation, these tumours may be caused by one or more highly penetrant disease alleles from the chromosomal instability pathway. CONCLUSION: These data show that HNPCC includes at least two entities with clinical and molecular differences. This will have implications for surveillance programmes and for cancer research.

Adaptor Proteins, Signal Transducing↗
PubMed2005

COX2 expression, angiogenesis, proliferation and survival in Barrett's cancer.

OBJECTIVES: To examine COX2 expression and its relation to angiogenesis, Ki67 and Bcl2 expression in Barrett's cancer. METHODS: Specimens from 48 R0-resected Barrett's adenocarcinoma were immunostained for cyclooxygenase 2 (COX2), CD 31 and alpha-sm actin to discriminate between mature and immature vessels, Mib-1 and Bcl2. COX2 staining, angiogenesis, Ki67 expression and Bcl2 expression were also measured. RESULTS: COX2 expression was increased in 25 of 48 cases. There was no significant correlation between COX2 expression and age, sex and tumor differentiation. A significant association was found between lymph node positive cases and elevated COX2 expression (p=0.008). The percentage of Ki67 positive cancer cells was 43.8% (range 15.4-67.5%) in the low COX2 group and 57.8% (range 12.0-84.6%) in the high COX2 group. The difference was statistically significant (p=0.046). The median neovascularisation coefficient in the low COX2 group was 11.68 (range 8.22-43.64) and 25.47 (range 8-38.3) in the high COX2 group. The difference was statistically significant (p=0.012). A significant difference in survival was observed between patients in the COX2 low category when compared with the COX2 high category (log-rank test p=0.013). CONCLUSIONS: Elevated COX2 expression is associated with lymph-node metastases and reduced survival in Barrett's cancer. This appears to be related to the induction of angiogenesis and proliferation.

Barrett Esophagus↗
PubMed2005

The innate immune response to Entamoeba histolytica lipopeptidophosphoglycan is mediated by toll-like receptors 2 and 4.

Entamoeba histolytica is a human pathogen that may invade the intestinal mucosa, causing amoebic colitis or hepatic abscesses when the trophozoites travel through the portal circulation to the liver. Lipopeptidophosphoglycan (LPPG) is a molecular pattern of E. histolytica recognized by the human immune system. Here we report that LPPG is exposed on the cell surface of E. histolytica trophozoites, and is recognized by the host through toll-like receptor (TLR) 2 and TLR4. Correspondingly, human embryonic kidney (HEK)-293 cells were rendered LPPG responsive through overexpression of TLR2 or TLR4/MD2. Moreover, co-expression of CD14 enhanced LPPG signal transmission through TLR2 and TLR4. The interaction of LPPG with TLR2 and TLR4 resulted in activation of NF-kappaB and release of interleukin (IL)-10, IL-12p40, tumour necrosis factor (TNF)-alpha, and IL-8 from human monocytes. Consistent with these findings, responsiveness of mouse macrophages lacking TLR2 expression (TLR2-/-) or functional TLR4 (TLR4d/d) to E. histolytica LPPG challenge was impaired while double deficient macrophages were unresponsive. In contrast to wild-type control and TLR2-/- animals succumbing to lethal shock syndrome, TLR4d/d mice were resistant to systemic LPPG challenge-induced pathology.

Animals↗
PubMed2004

[Esophageal perforation by portions of a wild boar].

We report a case of esophageal perforation by impacted portions of a wild boar. The 77-year-old patient was admitted 5 days after an opulent dinner. He complained of dysphagia and retrosternal pain and showed signs of severe sepsis. Endoscopy revealed meat and bone portions impacted in the esophagus. Surprisingly, impactation had not happened near any of the anatomical narrowings, but in the middle third. A CT scan showed penetration of the foreign body into the mediastinum and purulent mediastinitis. The patient underwent transthoracic esophagectomy and drainage of the severe, purulent mediastinal infection. Postoperative multi organ failure required a prolonged treatment in the intensive care unit. After recovery the gastrointestinal continuity was restored with gastric pull-up in the anterior mediastinum. The further course was uneventful.

Aged↗
PubMed2004

The genome of Desulfotalea psychrophila, a sulfate-reducing bacterium from permanently cold Arctic sediments.

Desulfotalea psychrophila is a marine sulfate-reducing delta-proteobacterium that is able to grow at in situ temperatures below 0 degrees C. As abundant members of the microbial community in permanently cold marine sediments, D. psychrophila-like bacteria contribute to the global cycles of carbon and sulfur. Here, we describe the genome sequence of D. psychrophila strain LSv54, which consists of a 3 523 383 bp circular chromosome with 3118 predicted genes and two plasmids of 121 586 bp and 14 663 bp. Analysis of the genome gave insight into the metabolic properties of the organism, e.g. the presence of TRAP-T systems as a major route for the uptake of C(4)-dicarboxylates, the unexpected presence of genes from the TCA cycle, a TAT secretion system, the lack of a beta-oxidation complex and typical Desulfovibrio cytochromes, such as c(553), c(3) and ncc. D. psychrophila encodes more than 30 two-component regulatory systems, including a new Ntr subcluster of hybrid kinases, nine putative cold shock proteins and nine potentially cold shock-inducible proteins. A comparison of D. psychrophila's genome features with those of the only other published genome from a sulfate reducer, the hyperthermophilic archaeon Archaeoglobus fulgidus, revealed many striking differences, but only a few shared features.

Arctic Regions↗
PubMed2004

The Munich Barrett follow up study: suspicion of Barrett's oesophagus based on either endoscopy or histology only--what is the clinical significance?

BACKGROUND: The incidence of distal oesophageal adenocarcinoma is rising, with chronic reflux and Barrett's oesophagus being considered risk factors. Reliable detection of Barrett's oesophagus during upper endoscopy is therefore mandatory but requires both endoscopy and histology for confirmation. Appropriate management of patients with endoscopic suspicion but negative on histology, or vice versa, or of patients with no endoscopic suspicion but with a biopsy diagnosis of intestinal metaplasia at the gastro-oesophageal junction, has not yet been studied prospectively. PATIENTS AND METHODS: In a prospective multicentre study, 929 patients (51% male, mean age 50 years) referred for upper gastrointestinal endoscopy were included; 59% had reflux symptoms. The endoscopic aspect of the Z line and any suspicion of Barrett's oesophagus were noted, and biopsies were taken in all patients from the Z line (n = 4), gastric cardia (n = 2), and body and antrum (n = 2 each). Biopsies positive for specialised intestinal metaplasia (SIM) were reviewed by a reference pathologist for a final Barrett's oesophagus diagnosis. All patients with endoscopic and/or histological suspicion of Barrett's oesophagus were invited for a follow up endoscopy; the remaining cases (no endoscopic or histological suspicion of Barrett's oesophagus) were followed clinically. RESULTS: Of 235 patients positive for Barrett's oesophagus on endoscopy and/or histology, 63% agreed to undergo repeat endoscopy (mean follow up period 30.5 months). 46% of patients with an endoscopic Barrett's oesophagus diagnosis but no histological confirmation (group A) showed the same distribution, a further 42% did not have Barrett's oesophagus, and 11% had confirmed Barrett's oesophagus on both endoscopy and biopsy on follow up. In the group with a histological Barrett's oesophagus diagnosis but negative on initial endoscopy (group B), follow up showed the same in 26% whereas 46% had no Barrett's oesophagus, and confirmed Barrett's oesophagus (endoscopy plus histology) was diagnosed in 17%. Of the study population, 16 patients had Barrett's oesophagus on initial endoscopy confirmed by histology which remained constant in 70% at follow up (group C). Of the remaining patients without an initial Barrett's oesophagus diagnosis on either endoscopy or histology (group D) and only clinical follow up (mean follow up period 38 months), one confirmed Barrett's oesophagus case was found among 100 patients re-endoscoped outside of the study protocol. However, no single case of dysplasia or cancer of the distal oesophagus was detected in any patient during the study period. CONCLUSIONS: Even in a specialised gastroenterology setting, reproducibility of presumptive endoscopic or histological diagnoses of Barrett's oesophagus at follow up were poor. Only 10-20% of cases with either endoscopic or histological suspicion of Barrett's oesophagus had established Barrett's oesophagus after 2.5 years of follow up. The risk of dysplasia in this population was very low and hence meticulous follow up may not be required.

Adolescent↗
PubMed2003

[Condylar reconstruction after resection of an intracapsular stomach carcinoma metastasis].

BACKGROUND: The mandible is a very uncommon place for a metastasis of a gastric carcinoma. Normally the area of the temporomandibular joint (TMJ) remains unaffected. The separate vascularization is discussed as one reason among others. Primary reconstruction after resection of the condyle is often problematic because an early onset of adjuvant systemic therapy is required. In this case, the insertion of a Quinn joint prosthesis is presented after resection of a TMJ metastasis. CASE: We report a hematogenic metastatic gastric adenocarcinoma in a 51-year old male who initially presented with increasing disclusion in the left molar region. Suspecting a metastatic adenocarcinoma of the TMJ, a condylectomy with immediate replacement by a total joint prosthesis was performed via a preauricular approach. Corresponding to the clinically and radiologically suspected diagnosis, the decalcified histological specimen presented as a metastatic gastric adenocarcinoma within the intracapsular region. RESULTS: The healing period of the implanted modified Quinn prosthesis was fast and uncomplicated after resection of this, to our knowledge, first documented metastatic gastric adenocarcinoma of the intracapsular region. After early restoration of joint function and patient satisfaction, the required radiochemotherapy of further unresectable bony metastases could be started in time. DISCUSSION: This example of an extremely rare case of a metastasis shows that such a total joint prosthesis appears to be a very good alternative to extended autogenous reconstruction or an unsatisfactory primary resection. Due to the mating of the spherical condylar head and glenoid fossa, the modified Quinn prosthesis is very suitable for total joint replacement after extended resection or in multiply preoperated cases.

Adenocarcinoma↗
PubMed2003

The 'angiogenic switch' in the progression from Barrett's metaplasia to esophageal adenocarcinoma.

AIMS: We investigated VEGF expression and neovascularisation in the metaplasia-dysplasia-carcinoma sequence of Barrett's esophagus and 47 shades of adenocarcinoma. METHOD: Slides of 27 cases of Barrett's metaplasia and high grade dysplasia were immunostained for VEGF, CD 31 and alpha-sm actin to discriminate between mature and immature vessels. VEGF stained slides were quantitatively evaluated measuring optical density with a computer based program. The neovascularisation coefficient was estimated with an interactive analytic computer program. RESULTS: The median VEGF expression increased from metaplasia to advanced carcinoma. VEGF expression and the neovascularisation coefficient reached statistical significance between Barrett's metaplasia and high grade dysplasia (p<0.001), but were not statistically different between high grade dysplasia and microinvasive carcinoma (p=0.421; p=0.146). Comparing microinvasive to advanced carcinoma the difference was significant for both parameters (p<0.001). CONCLUSIONS: Based on a quantitative computer based evaluation program, the present study suggests, that an angiogenic switch might exist and that it is an early event in the metaplasia-dysplasia-carcinoma sequence of Barrett's carcinoma. The neovascularisation phase in Barrett's carcinoma may precede tumour growth.

Adenocarcinoma↗
PubMed2003

Delayed aortic rupture after radiochemotherapy and esophagectomy for esophageal cancer.

Spontaneous rupture of major vessels is a known though rare complication in treatment of patients with esophageal cancer, but its pathophysiology is not very well understood. We herein report about the sudden death of a 42-year-old man due to spontaneous aortic rupture, 11 days after transthoracic esophagectomy. Because of a locally advanced squamous cell carcinoma of the distal esophagus, which was considered irresectable at the time of presentation, the patient had received one course of chemotherapy followed by synchronous chemoradiation (60 Gy, 5-fluorouracil and cisplatin) prior to surgery. We discuss the patho-anatomic findings of the postmortem examination concerning alterations of the aortic wall and the potential correlations with aggressive radiochemotherapy protocols.

Adult↗
PubMed2002

[Breast scintigraphy using 99mTc-sestamibi--use and limitations].

AIM: Until now scintimammography did not achieve any definite role in the assessment of breast lesions. Purpose of this study was to elaborate its use as well as the limitations of scintimammography after 500 examinations completed. METHODS: Scintigraphic findings were correlated with the histopathologic outcome of 219 patients, who underwent surgery or biopsy for histopathological confirmation. The results were determined with respect to palpability of the lesion and tumour size. Additionally, a distinct analysis was performed for the patient subpopulation with indeterminate results of previously performed physical examination, mammography, and sonography. RESULTS: Overall sensitivity for scintimammography was 82.1% at a specificity of 87.5%. For palpable lesions sensitivity was 91.7% which was evidently higher as compared to 64.9% for non palpable lesions. For palpable lesions specificity was 81.1% and 88.6% for non palpable lesions. According to tumour size sensitivity ranged between 65.2% for carcinoma with a diameter < 1 cm and 93.7% for carcinoma > 1 cm. In the patients subgroup with indeterminate preliminary diagnosis (n = 143) sensitivity decreased to 71.7% at a specificity of 87.8%. Patients undergoing neoadjuvant chemotherapy showed decreasing sestamibi uptake as early as 8 days after therapy if tumour response was evident. However, small residual invasive tumours in patients with complete remission could not be visualised. CONCLUSION: Scintimammography is neither suited for screening, nor early diagnosis of breast cancer, nor for the further evaluation of small and unclear mammographic findings. Scintimammography should not be used whenever histopathological clarification of a suspicious lesion is necessary. It is useful to further investigate patients with unclear or probably benign findings in physical examination and/or mammography and to monitor tumour response to neoadjuvant chemotherapy.

Breast↗
PubMed2001

HIV type 1 Nef promotes neoplastic transformation of immortalized neural cells.

To study the effects of HIV-1 Nef on CNS-derived cells in vivo, an expression system based on the murine neural stem cell line C17.2 was established. Stable expression of LAV-1(Bru)-nef in these cells induced a transformed phenotype and enhanced cell growth in soft agar. Further experiments using previously established nef-expressing human astrocytoma cell lines as well as nef-expressing murine fibroblasts suggested a brain cell-specific transforming activity of Nef. After implantation into syngeneic or nude mice both murine and human nef-expressing CNS-derived cells induced tumor development. Interestingly, human astrocytoma cells expressing a Nef mutant carrying a disrupted SH3-binding motif involved in protein-protein interactions failed to induce tumor formation. These in vivo data suggest that Nef promotes neoplastic transformation of immortalized murine neural stem cells and enhances malignancy of low-tumorigenic human astrocytoma cells. Nef may therefore be involved in the development of AIDS-associated brain tumors.

Animals↗
PubMed2001

Highly specific tumor binding of a 213Bi-labeled monoclonal antibody against mutant E-cadherin suggests its usefulness for locoregional alpha-radioimmunotherapy of diffuse-type gastric cancer.

A monoclonal antibody (E-cadherin delta 9-1) directed against a characteristic E-cadherin mutation (in-frame deletion of exon 9), found in diffuse-type gastric cancer but not in any normal tissue, was conjugated with the high linear energy transfer alpha-emitter 213Bi and tested for its binding specificity in s.c. and i.p. nude mice tumor models. After intratumoral application in s.c. tumors expressing mutant E-cadherin, the 213Bi-labeled antibody was specifically retained at the injection site as shown by autoradiography. After injection into the peritoneal cavity, uptake in small i.p. tumor nodules expressing mutant E-cadherin was 17-fold higher than in tumor nodules expressing wild-type E-cadherin (62% injected dose/g versus 3.7% injected dose/g). 78% of the total activity in the ascites fluid was bound to free tumor cells expressing mutant E-cadherin, whereas in control cells, binding was only 18%. The selective binding of the 213Bi-labeled, mutation-specific monoclonal antibody E-cadherin delta 9-1 suggests that it will be successful for alpha-radioimmunotherapy of disseminated tumors after locoregional application.

Animals↗
PubMed2001

Key importance of the Helicobacter pylori adherence factor blood group antigen binding adhesin during chronic gastric inflammation.

Helicobacter pylori has been assigned as a class I carcinogen because of its relation to gastric adenocarcinoma. Chronic H. pylori infection may lead to severe gastritis, glandular atrophy (AT), and intestinal metaplasia (IM). Strains secreting the vacuolating toxin VacA and producing the cytotoxin-associated antigen CagA (type 1 strains), as well as the blood group antigen binding adhesin (BabA) targeting Lewis(b) antigens, have been associated previously with distal gastric adenocarcinoma (M. Gerhard et al., Proc. Natl. Acad. Sci. USA, 96: 12778-12783, 1999) and may therefore also be related to lesions preceding gastric cancer. Antral and corpus biopsies were collected from 451 patients; 151 were H. pylori positive, as determined by PCR. Gastric biopsies were histologically evaluated for activity of gastritis (G0-G3, granulocyte infiltration), chronicity of gastritis (L1-L3, lymphocyte infiltration), and the presence of IM and/or AT according to the Sydney classification. Simultaneously, the presence of bacterial genes encoding virulence and adherence factors (racAs1/s2, cagA, and babA2) was determined by PCR. The presence of cagA+ and vacAs1 (alone or combined) both correlated with activity and chronicity of gastritis (P < 0.05); however, the overall prevalence of these genes was 60 or 72%, respectively, and was thus relatively frequent. The babA2 gene, encoding the adhesin BabA, was detected in 38% of infected patients and was correlated with the activity of gastritis in antrum and corpus (P < 0.005). cagA+/vacAs1+ strains (suggesting the presence of type 1 strains) that were also babA2 positive were detected more frequently in patients with severe histological alterations (such as G3, IM, or AT) compared with subjects without these changes (P < 0.01). cagA+/vacAs1+ strains that were babA2 negative, however, lacked a significant correlation with severe histological changes, activity, or chronicity of gastritis in antrum and corpus. Adherence of H. pylori via BabA appears to be of importance for efficient delivery of VacA and CagA and may play a special role in the pathogenesis of severe histological changes.

Adhesins, Bacterial↗
PubMed2001

Proliferation kinetics and prognosis in gastric cancer after resection.

The influence of proliferation and proliferation kinetics on prognosis in gastric cancer after complete resection are controversial. In a prospective study we investigated the tumour specimens of 111 patients after resection of gastric cancer, who received 200 mg intravenous (i.v.) bromodeoxyuridine (BrdU) pre-operatively. The following biological parameters were analysed in the tumour tissue using flow-cytometry: DNA ploidy, proportion of S-phase cells, BrdU labelling index (LI), DNA synthesis time (T(s)), potential tumour doubling time (T(pot)), proliferating cell nuclear antigen (PCNA) and Ki-67 LI. The median follow-up time was 40 months (range 19-62 months). Besides the established pathohistological prognostic factors, univariate analysis revealed a prognostic influence on survival for BrdU LI, T(pot) and the proportion of S-phase cells. By multivariate Cox analysis of the completely resected cases, only tumour stage and T(pot) had a significant, independent influence on survival. By classification and regression trees (CART) analysis, resection status, tumour stage and T(pot) defined risk groups with significantly different outcomes. A short T(pot) was a predictor of better survival in stage I, II and IIIA tumours. Ploidy and the other investigated proliferation-related parameters failed to demonstrate any influence on prognosis after resection of gastric cancer.

Adenocarcinoma↗
PubMed2001

The European perspective of psychiatric reform.

OBJECTIVE: To provide a framework of mental health care reform across Europe. METHOD: On the basis of summary quantitative indices and expert ratings of broad aspects of mental health care structure, the process and outcome of psychiatric reform common trends and differences are outlined. RESULTS: There has been a broad trend away from an institutional model of care with the mental hospital as the dominant institution, and community- and general hospital-based mental health services of varying comprehensiveness are in place in most countries. The social and broad community aspects of psychiatric reform have generally been somewhat less successful than changes in service set-up. Assessment of reform outcomes proves particularly difficult. CONCLUSION: Psychiatric reform processes have achieved some of their aims, and there are broadly similar trends. Regional variation is substantial and may be as important as cross-national differences. Mental health care reform is ongoing across the European region.

Europe↗