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Biomedical subjects

Peter Bauerfeind

Publications and source records attributed to Peter Bauerfeind.

18 recordsLinked to original sources
PubMed2006

Acute gastrointestinal bleeding: detection of source and etiology with multi-detector-row CT.

This study was conducted to determine the ability of multi-detector-row computed tomography (CT) to identify the source and etiology of acute gastrointestinal bleeding. Eighteen patients with acute upper (n = 10) and lower (n = 8) gastrointestinal bleeding underwent 4-detector-row CT (n = 6), 16-detector-row CT (n = 11), and 64-slice CT (n = 1) with an arterial and portal venous phase of contrast enhancement. Unenhanced scans were performed in nine patients. CT scans were reviewed to determine conspicuity of bleeding source, underlying etiology, and for potential causes of false-negative prospective interpretations. Bleeding sources were prospectively identified with CT in 15 (83%) patients, and three (17%) bleeding sources were visualized in retrospect, allowing the characterization of all sources of bleeding with CT. Contrast extravasation was demonstrated with CT in all 11 patients with severe bleeding, but only in 1 of 7 patients with mild bleeding. The etiology could not be identified on unenhanced CT scans in any patient, whereas arterial-phase and portal venous-phase CT depicted etiology in 15 (83%) patients. Underlying etiology was correctly identified in all eight patients with mild GI bleeding. Multi-detector-row CT enables the identification of bleeding source and precise etiology in patients with acute gastrointestinal bleeding.

Acute Disease↗
PubMed2006

Efficacy and safety of botulinum toxin a injection compared with topical nitroglycerin ointment for the treatment of chronic anal fissure: a prospective randomized study.

OBJECTIVES: To evaluate the efficacy and safety of botulinum toxin A injection compared with topical nitroglycerin ointment for the treatment of chronic anal fissure (CAF). METHODS: Fifty outpatients with CAF were randomized to receive either a single botulinum toxin injection (30 IU Botox) or topical nitroglycerin ointment 0.2% b.i.d. for 2 wk. If the initial therapy failed, patients were assigned to the other treatment group for a further 2 wk. If CAF still showed no healing at wk 4, patients received combination therapy of botulinum toxin and nitroglycerin for 4 additional wk. Persisting CAF at wk 8 was treated according to the investigator's decision. Healing rates, symptoms, and side effects of the therapy were recorded at wk 2, 4, 8, 12, and 24 after randomization. RESULTS: The group initially treated with nitroglycerin showed a higher healing rate of CAF (13 of 25, 52%) as compared with the botulinum toxin group (6 of 25, 24%) after the first 2 wk of therapy (p < 0.05). At the end of wk 4, CAF healed in three additional patients, all receiving nitroglycerin after initial botulinum toxin injection. Mild side effects occurred in 13 of 50 (26%) patients, all except one were on nitroglycerin. CONCLUSIONS: Nitroglycerin ointment was superior to the more expensive and invasive botulinum toxin injection for initial healing of CAF, but was associated with more but mild side effects.

Administration, Topical↗
PubMed2006

Nickel represses the synthesis of the nickel permease NixA of Helicobacter pylori.

Nickel acquisition is necessary for urease activity, a major virulence factor of the human gastric pathogen Helicobacter pylori. NixA was identified as a specific nickel uptake system in this organism. Addition of small amounts of nickel to media strongly stimulates urea hydrolysis. On the other hand, high nickel concentrations are deleterious to cell growth. As a possible protective reaction, nickel uptake seems to be reduced in H. pylori grown in nickel-rich media. These observations led to investigations of regulation of the expression of the nickel permease NixA. We found that increasing the nickel concentration in media reduced the amount of NixA. In order to address the question of whether this phenomenon was subject to transcriptional or translational regulation, we quantified nixA mRNA from H. pylori by real-time PCR. The amount of nixA mRNA was gradually reduced five- to sevenfold in a time- and concentration-dependent manner. Repression could be measured as soon as 5 min after nickel addition, and the maximum repression occurred after 20 to 30 min. The maximum repression was obtained with an external nickel concentration of 100 microM. The observed nickel repression of NixA was dependent on nikR encoding the nickel-responsive regulatory protein NikR. In conclusion, we demonstrated that synthesis of the NixA nickel permease of H. pylori shows nickel-responsive regulation mediated by NikR to maintain the balance between effective nickel acquisition and a toxic overload.

Bacterial Proteins↗
PubMed2005

Improved capsule endoscopy after bowel preparation.

BACKGROUND: The diagnostic yield of capsule endoscopy depends on the quality of visualization of the small-bowel wall and complete passage through the small bowel. This study examined the effect of bowel preparation on the volume of intestinal content and on small-bowel transit. METHODS: Sixty-one consecutive patients (34 men, 27 women; mean age 56 years, range 17-88 years) were enrolled in the study. Although not randomized, 33 patients received a bowel preparation, and 28 had no preparation. Gastric emptying, small-bowel transit time, overall preparation assessment, and bowel-wall visualization were evaluated by 3 investigators who were unaware of whether the patient had undergone bowel preparation. RESULTS: Small-bowel transit time was significantly shorter in patients with bowel preparation (median 213 minutes: 95% CI[190, 267]) than in those without preparation (median 253 minutes: 95% CI[228, 307]) (p <0.01). The capsule reached the cecum in 97% of patients in the bowel-preparation group, compared with 76% in the nonpreparation group (p=0.02). Bowel preparation improved the quality of visualization significantly; this effect was more pronounced in the distal small bowel. CONCLUSIONS: This study demonstrated that bowel preparation accelerates small-bowel capsule transit and leads to a higher rate of complete capsule endoscopy. Visualization of the small bowel was improved by bowel preparation. Bowel preparation before capsule endoscopy is recommended.

Adolescent↗
PubMed2005

Positron emission tomography/computed tomography influences on the management of resectable pancreatic cancer and its cost-effectiveness.

OBJECTIVE: We sought to determine the impact of positron emission tomography/computed tomography (PET/CT) on the management of presumed resectable pancreatic cancer and to assess the cost of this new staging procedure. SUMMARY BACKGROUND DATA: PET using 18F-fluorodeoxyglucose (FDG) is increasingly used for the staging of pancreatic cancer, but anatomic information is limited. Integrated PET/CT enables optimal anatomic delineation of PET findings and identification of FDG-negative lesions on computed tomography (CT) images and might improve preoperative staging. MATERIAL AND METHODS: Patients with suspected pancreatic cancer who had a PET/CT between June 2001 to April 2004 were entered into a prospective database. Routine staging included abdominal CT, chest x-ray, and CA 19-9 measurement. FDG-PET/CT was conducted according to a standardized protocol, and findings were confirmed by histology. Cost benefit analysis was performed based on charged cost of PET/CT and pancreatic resection and included the time frame of staging and surgery. RESULTS: Fifty-nine patients with a median age of 61 years (range, 40-80 years) were included in this analysis. Fifty-one patients had lesions in the head and 8 in the tail of the pancreas. The positive and negative predictive values for pancreatic cancer were 91% and 64%, respectively. PET/CT detected additional distant metastases in 5 and synchronous rectal cancer in 2 patients. PET/CT findings changed the management in 16% of patients with pancreatic cancer deemed resectable after routine staging (P = 0.031) and was cost saving. CONCLUSIONS: PET/CT represents an important staging procedure prior to pancreatic resection for cancer, since it significantly improves patient selection and is cost-effective.

Adenocarcinoma↗
PubMed2004

Retroperitoneal perforation of the colon caused by colonic tuberculosis: report of a case.

We present a 25-year-old, HIV-negative patient from Kosovo, with no significant past medical history, who was admitted to a local hospital for nonspecific upper abdominal discomfort. He was transferred to us after a retroperitoneal mass with contact to the right colonic flexure had been found during workup. Colonoscopy demonstrated an edemateous area with a central fistula in the right flexure, and histology showed caseous necrosis. Although neither bacteriology nor histology could detect any germs, gastrointestinal tuberculosis seemed to be very probable. Laparotomy with a segmental resection of the colon was performed to remove the fistula-bearing segment, and histologic examination of the resected specimen confirmed the intraoperative suspect of a retroperitoneal colonic perforation. Again, all cultures from the specimen were negative for tuberculosis, but polymerase chain reaction of a regional lymph node revealed acid-fast bacilli of the Mycobacterium tuberculosis/bovis species. Although the patient had no other sites of tuberculosis infection like pulmonary or urinary, he received adjuvant standard tuberculosis treatment for six months. At control examination one year after the operation, the patient was free of recurrence and in very good general condition. We report this extremely rare presentation of gastrointestinal tuberculosis to sensitize physicians to tuberculosis again, because incidence rates are increasing and this disease will certainly play a more important role in the future.

Abdominal Pain↗
PubMed2004

Patient-controlled analgesia and sedation in gastrointestinal endoscopy.

Variations in pain threshold, drug tolerance, and visceral sensitivity among patients make it difficult to anticipate the appropriate dose of sedation for gastrointestinal endoscopy. Propofol was recently introduced for sedation in endoscopy and has a rapid onset and offset of action, making it an ideal substance for patient-controlled administration. Several controlled trials have demonstrated that during colonoscopy, patient-controlled application of propofol alone or in combination with various opioids is effective,safe, and yields high patient satisfaction. Target-controlled infusion of propofol has shown encouraging results for prolonged upper endoscopy procedures like endoscopic retrograde cholangio pancreatography.

Analgesia, Patient-Controlled↗
PubMed2003

Living donor liver transplantation and tolerance: a potential strategy in cholangiocarcinoma.

BACKGROUND: Donor-specific immune tolerance has been reported in isolated cases of kidney transplantation associated with bone marrow transplantation. The following is a description of a living donor liver transplantation for a hilar cholangiocarcinoma in a previous recipient of an allogeneic bone marrow transplant. METHOD: A right hemi-liver transplantation was performed using a liver allograft obtained from the same previous bone marrow donor. A neoadjuvant chemo-irradiation protocol was implemented before the procedure. Because of the presence of full chimerism, no immunosuppression has been necessary for the last 22 months. RESULTS: Liver graft function has remained excellent, and a magnetic resonance imaging scan at one and a half years has shown no tumor recurrence. A control liver biopsy at 1 year showed no rejection. CONCLUSIONS: Neoadjuvant chemo-irradiation therapy and removal of all immunosuppression after liver transplantation formed the basic structure of this approach. Additional benefits provided by living donor liver transplantation included limitation of tumor progression by diminishing the pretransplantation waiting time, radical excision of the tumor through a complete hepatectomy, and optimal timing of the transplant procedure within a neoadjuvant chemo-irradiation protocol.

Adult↗
PubMed2002

The presence of more than two index adenomas is the strongest predictor of metachronous colon adenomas.

QUESTION UNDER STUDY: To assess whether patient or adenoma characteristics at index colonoscopy could be predictors of metachronous adenomas and of advanced metachronous adenomas at first surveillance colonoscopy. METHODS: This retrospective study evaluated polypectomies of 372 adenomas in 214 patients who underwent a first follow-up colonoscopy after a median of 17 months. Logistic regression analysis was used to assess the association of baseline patient and adenoma characteristics with the development of any metachronous adenomas and of advanced adenomas (>1.0 cm, or villous component, or severe dysplasia, or early cancer). RESULTS: Eighty-one patients (38%) demonstrated 130 metachronous adenomas including 21 cases (10%) with advanced adenomas. The presence of more than 2 baseline adenomas was significantly associated with the finding of adenomas at follow-up (odds ratio 2.44, 95% confidence interval 1.27-4.68, p = 0.010). Patient age (>or= 60 versus <60) and size of largest adenoma (>1.0 cm versus <or= 1.0 cm) demonstrated borderline significance. However, neither gender, most advanced histology (tubulo-villous/villous versus tubular), nor most advanced dysplasia (severe/early cancer versus mild/moderate) at baseline colonoscopy were related with the development of metachronous adenomas. Furthermore, none of the analysed patient and polyp characteristics demonstrated an association with the development of advanced metachronous adenomas. CONCLUSION: Patients with over 2 adenomas at baseline colonoscopy are at highest risk for the finding of adenomas at follow-up.

Adenoma↗
PubMed2002

Yucatec Mayan medicinal plants: evaluation based on indigenous uses.

As part of an ethnopharmacological field study 48 medicinal plants were evaluated using several biological assays with the goal to obtain information on the pharmacological effects of these plants, which may be of direct relevance to the indigenous uses. Three species used to treat gastrointestinal disorders showed remarkable activity against Helicobacter pylori. One of them showed activity against Giardia duodenalis. Cytotoxic effects against KB cells were found for six species. In the group of plants used for dermatological conditions several species were active against gram-positive bacteria and Candida albicans. Two plant species of this group were found to be active in an Nuclear Factor-kappaB (NF-kappaB) assay measuring inhibition of this pro-inflammatory transcription factor. A species of the Solanaceae, applied in cases of pain and fever, showed a weak activity against Plasmodium falciparum. One species traditionally used for diabetes exhibited antihyperglycemic activity. None of the six species from the group of 'women's medicine' showed relevant affinity to the D(2) dopamine receptor. Based on this evaluation, plants with strong activities should be further investigated phytochemically and pharmacologically to identify active fractions and compounds.

Animals↗
PubMed2002

Conserved low-affinity nickel-binding amino acids are essential for the function of the nickel permease NixA of Helicobacter pylori.

Nickel acquisition is necessary for urease activity, a major virulence factor of the human gastric pathogen Helicobacter pylori. The nickel permease NixA of H. pylori is a member of the single-component nickel-cobalt transporter family. To identify functionally relevant amino acids of NixA, single-site exchanges were introduced into NixA via PCR-based mutagenesis. This study investigated one of the recognition motifs for this family in transmembrane segment III and other conserved amino acids, mostly with possible nickel-binding capacities. The mutant alleles were expressed in Escherichia coli, and activity of the altered permeases was analyzed by measuring nickel accumulation and urease activity. Expression was checked by immunoblotting after sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a NixA-specific antibody. Replacement of Phe-75 and His-79-both part of the characteristic sequence motif-and of Asn-127, Thr-195, and Ser-197 with alanine abolished nickel uptake in the E. coli system. The results were unchanged if these amino acids were replaced with residues more similar to the original amino acid. The phenotype of the null mutants was independent of the culture medium. Mutation of Val-82, Tyr-242, Thr-260, His-181, and His-15 strongly affected uptake activity under nickel limitation on complex Luria-Bertani medium but had little effect in minimal medium. Eight other conserved amino acids (Ser-80, Ser-81, Phe-119, Trp-180, Tyr-183, Trp-244, Pro-249, and Asn-256) were found to be dispensable for the function of NixA. These results show that atypical nickel-binding amino acids play an important function in nickel uptake and that most of the essential amino acids are clustered in conserved motifs.

Amino Acid Motifs↗
PubMedDate not supplied

Expression of COX-2 and Wnt pathway genes in adenomas of familial adenomatous polyposis patients treated with meloxicam.

BACKGROUND: Familial adenomatous polyposis (FAP) is an autosomal, dominantly inherited predisposition to colorectal cancer caused by germline mutations within the adenomatous polyposis coli (APC) gene, a key member of the Wnt signalling pathway. A new class of non-steroidal anti-inflammatory drugs (NSAIDs), the specific cyclooxygenase 2 (COX-2) inhibitors, have recently been applied for the treatment of FAP patients. PATIENTS AND METHODS: The expressions of the Wnt members and targets APC, c-myc, cyclin D1 and COX-2, as measured by real-time quantitative RT-PCR, have been evaluated in fresh samples of normal colorectal mucosa and matched adenoma tissue of six unrelated FAP patients before and after treatment with meloxicam. RESULTS: A significant up-regulation of COX-2 in adenomas after treatment with meloxicam was found. Furthermore, in adenomas, a down-regulation of APC after treatment and a tight correlation of the expressions of the two Wnt targets, c-myc and cyclin D1, in both stages of treatment were observed. CONCLUSION: A feedback loop mediated by the peroxisome proliferator-activated receptor (PPAR) gamma is discussed as being responsible for the up-regulation of COX-2

Adenomatous Polyposis Coli↗
PubMedDate not supplied

Overexpression of Wnt target genes in adenomas of familial adenomatous polyposis patients.

Germline mutations within the adenomatous polyposis coli (APC) gene, a key member of the Wnt signalling pathway, have been shown to cause adenoma development in familial adenomatous polyposis (FAP), a dominantly inherited predisposition to colorectal cancer. Although it has been suggested for several years that alterations within the Wnt pathway are the underlying events for the development of colorectal adenomas in FAP patients, no detailed analysis of the gene expressions of Wnt pathway members has been available in fresh colorectal tissue of FAP patients, so far. Thus, we investigated potential differences in the expressions of APC and its Wnt partners conductin, beta-catenin, cyclin D1, and c-myc in normal colorectal mucosa and matched adenoma tissue of 14 FAP patients using real-time quantitative PCR. The expressions of both Wnt target genes, cyclin D1 and c-myc, were significantly increased in adenoma compared to matched normal mucosa. Furthermore, the overexpressions of these two genes showed a highly significant positive correlation. Our data suggest that the concomitant overexpression of the Wnt targets and cell cycle regulators cyclin D1 and c-myc plays an important role in the neoplastic proliferation of adenomas in FAP patients.

Adenomatous Polyposis Coli↗