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H D Becker

Publications and source records attributed to H D Becker.

At least 37 records · Page 2Linked to original sources
PubMed2002

Evaluation of the barostat for recordings of gastrointestinal motility.

BACKGROUND: The barostat has been used to investigate gastrointestinal motility. No detailed technical evaluation to characterize the properties of this device for motility recordings has been reported. We, therefore, aimed to test the barostat in vitro under standardized conditions. METHODS: Barostat and manometry recordings were performed using a combined catheter in a pressure chamber. Some of the experiments were made in pig sigmoid colon in order to mimic recordings in a hollow organ. Data are mean +/- SD. RESULTS: Baseline changes of the bag volume under constant conditions were 3.9 +/- 2.0%. The bag volume increased by 4.5 +/- 1.1% with a temperature increase from 22 to 37 degrees C (p < 0.05). At external pressures above the bag operating pressure, the barostat bag collapsed, while only minimal volume reductions occurred at external pressures below the bag pressure. Barostat recordings of pressure events were delayed when compared with manometry and not linearly related to the pressure increases. CONCLUSION: The influence of temperature changes on barostat recordings is small. The volume decrease in the barostat bag is not linearly related to the external pressure increase and influenced by the operating pressure in the bag. This experimental study provides insight and caveats for those planning to use the barostat device for motility recordings of the gastrointestinal tract.

Animals↗
PubMed2002

Cultivation of porcine hepatocytes in polyurethane nonwovens as part of a biohybrid liver support system.

Many patients suffering from end-stage liver disease cannot be transplanted within reasonable time due to the shortage of donor organs. Bioartificial liver support systems may contribute to the liver regeneration or bridging the time until a liver graft for transplantation becomes available. Nonwovens with integrated oxygenation capacity have been developed and manufactured by melt blow technology using thermoplastic polyurethane. Capillary membranes for oxygenation were integrated into the nonwoven during the processing. The polyurethane nonwoven structures with adapted pore size and high pore volume allow high cell densities in the hepatocyte culture. The three-dimensional cell culture was housed by a flow bioreactor system and was integrated in a closed loop circulation with monitoring possibilities for pressure, pH, temperature, ammonia, and oxygen. Hepatocytes were isolated from rats or pigs by collagenase perfusion and infused into the medium-perfused circulation. Cells showed high viability and hepatocyte specific cytochrome P450-dependent metabolic function in culture (MEGX test).

Albumins↗
PubMed2002

Endobronchial ultrasound-guided transbronchial lung biopsy in solitary pulmonary nodules and peripheral lesions.

Transbronchial biopsy (TBBX) for peripheral lung lesions is usually performed with the help of fluoroscopy, but the yield varies widely. This feasibility study aimed to assess the ability of endobronchial ultrasound (EBUS) to provide imaging guidance for TBBX. In a prospective study, 50 consecutive patients referred for TBBX for peripheral lesions underwent fluoroscopy-guided and EBUS-guided TBBX in random order. Diagnostic yields were compared for both modalities and feasibility was assessed for EBUS. Diagnostic material was obtained in 80% of patients with EBUS and 76% of patients with fluoroscopy. There was a nonsignificant trend for EBUS to be better than fluoroscopy for lesions <3 cm in diameter. Four lesions could not be visualised with EBUS. There were no significant complications associated with the use of EBUS. Endobronchial ultrasound-guided transbronchial biopsy is feasible. It appears to be at least equivalent to fluoroscopy without the accompanying radiation exposure. Further large-scale studies are indicated to assess the possible role of endobronchial ultrasound as a potential imaging method of choice for the biopsy of peripheral lung lesions.

Adult↗
PubMed2002

Endobronchial ultrasound in therapeutic bronchoscopy.

Endobronchial ultrasound (EBUS) has been introduced as an adjunct to diagnostic bronchoscopy as it allows evaluation of the submucosal and parabronchial structures. Its use in therapeutic bronchoscopy has not been assessed. A large observational study of the value of EBUS in therapeutic bronchoscopy is presented here. From January 1998-January 2001 all patients undergoing therapeutic bronchoscopy and EBUS were evaluated prospectively. Patient demographics, indication for bronchoscopy, interventional treatments used and changes in therapy as influenced by the use of EBUS were documented. A total 2,446 therapeutic bronchoscopies were performed. In 1,174 cases EBUS was used (29% mechanical tumour debridement, 20% airway stenting, 13% Neodymium:yttrium aluminium garnet (Nd:YAG) laser use, 23% argon plasma coagulation, 11% brachytherapy, 2% foreign body removal and 2% endoscopic abscess drainage). EBUS guided or changed therapy significantly in 43% of cases. Changes included adjustment of stent dimensions, termination of tumour debridement when nearing vessels, and referral for surgical interventions rather than endoscopic treatment. Complications associated with EBUS use were minimal. No patient undergoing EBUS guided tumour destruction experienced severe bleeding or fistula formation. In summary, endobronchial ultrasound was easily performed and changed or guided therapeutic decisions during therapeutic bronchoscopic procedures in a substantial number of cases. As this may result in better outcomes, it has become a standard adjunct in the authors practice.

Adult↗
PubMed2002

Aspirin does not increase bleeding complications after transbronchial biopsy.

STUDY OBJECTIVES: The present study was performed to determine whether the risk of bleeding after transbronchial lung biopsy is increased in patients taking aspirin. DESIGN: Prospective cohort study. PATIENTS AND INTERVENTIONS: After excluding patients with other coagulation problems, 1,217 patients who had undergone transbronchial lung biopsy during a prospective 1.5-year study period were included in this study. The use of aspirin was not discontinued before the procedure. Two hundred eighty-five patients (23%) had consumed aspirin within 24 h of the procedure, and most of them (82%) used aspirin on a daily basis. Transbronchial biopsies were performed, and the bleeding incidence was compared between the groups. RESULTS: A total of 57 patients (4.7%) experienced procedure-related bleeding. Minor bleeding occurred in 5 of 285 patients (1.8%) taking aspirin and in 27 of 932 control patients (2.9%; not significant). Moderate bleeding was seen in 3 of 285 patients (1.1%) in the aspirin group and in 13 of 932 patients (1.4%) in the control group (not significant). Major bleeding occurred in only 9 patients, 2 of 285 (0.9%) in the aspirin group and 7 of 932 (0.8%) in the control group (not significant). All bleeding was controlled by endoscopic means, and there were no fatalities and no need for blood transfusions. CONCLUSIONS: We conclude that the risk of severe bleeding after transbronchial lung biopsy is small (ie, < 1%) and that the use of aspirin is not associated with any increased risk of bleeding.

Adult↗
PubMed2001

A single amidotransferase forms asparaginyl-tRNA and glutaminyl-tRNA in Chlamydia trachomatis.

Aminoacyl-tRNA is generally formed by aminoacyl-tRNA synthetases, a family of 20 enzymes essential for accurate protein synthesis. However, most bacteria generate one of the two amide aminoacyl-tRNAs, Asn-tRNA or Gln-tRNA, by transamidation of mischarged Asp-tRNA(Asn) or Glu-tRNA(Gln) catalyzed by a heterotrimeric amidotransferase (encoded by the gatA, gatB, and gatC genes). The Chlamydia trachomatis genome sequence reveals genes for 18 synthetases, whereas those for asparaginyl-tRNA synthetase and glutaminyl-tRNA synthetase are absent. Yet the genome harbors three gat genes in an operon-like arrangement (gatCAB). We reasoned that Chlamydia uses the gatCAB-encoded amidotransferase to generate both Asn-tRNA and Gln-tRNA. C. trachomatis aspartyl-tRNA synthetase and glutamyl-tRNA synthetase were shown to be non-discriminating synthetases that form the misacylated tRNA(Asn) and tRNA(Gln) species. A preparation of pure heterotrimeric recombinant C. trachomatis amidotransferase converted Asp-tRNA(Asn) and Glu-tRNA(Gln) into Asn-tRNA and Gln-tRNA, respectively. The enzyme used glutamine, asparagine, or ammonia as amide donors in the presence of either ATP or GTP. These results suggest that C. trachomatis employs the dual specificity gatCAB-encoded amidotransferase and 18 aminoacyl-tRNA synthetases to create the complete set of 20 aminoacyl-tRNAs.

Amino Acyl-tRNA Synthetases↗
PubMed2001

Sensitive detection of rare cancer cells in sputum and peripheral blood samples of patients with lung cancer by preproGRP-specific RT-PCR.

RT-PCR-based amplification of transcripts expressed in cancer but not in normal non-neoplastic cells is increasingly used for the sensitive detection of rare disseminated or exfoliated cancer cells to improve cancer staging and early detection protocols. However, these assays are frequently hampered by false-positive test results due to low-level transcription of the marker genes in normal cells. To overcome these limitations, target transcripts have to be identified that are tightly suppressed in normal non-neoplastic tissues, whereas they should be actively transcribed in the respective cancer cells. Here, we tested RT-PCR assays for 7 neuroendocrine marker transcripts including NCAM, PGP 9.5, gastrin, gastrin receptor, synaptophysin, preprogastrin-releasing peptide (preproGRP) and GRP-receptor to detect rare exfoliated tumor cells in peripheral venous blood and sputum samples from patients with lung cancer. Among these preproGRP RT-PCR was the only assay with which illegitimate transcription in blood or sputum samples from healthy donors or patients with unrelated diseases did not interfere. However, it reproducibly detected up to 10 small-cell lung cancer cells diluted in either 10 ml blood or 5 ml sputum samples. Single blood and sputum samples were collected directly before diagnostic bronchoscopy from 175 patients suspected to have lung cancer. Twenty-six of these had small-cell lung cancer (SCLC). Thereof, 13 patients (50%) tested positive in the blood sample and 5 of 23 patients (22%) tested positive in the sputum sample. Moreover, among 92 patients with non-small-cell lung cancer (NSCLC) 25 patients (27%) had disseminated cancer cells in peripheral blood. Amplification of preproGRP transcripts from clinical samples is a sensitive and specific assay to detect disseminated or exfoliated lung cancer cells either in peripheral blood or sputum samples.

Biomarkers, Tumor↗
PubMed2001

Methanococcus jannaschii prolyl-cysteinyl-tRNA synthetase possesses overlapping amino acid binding sites.

The protein translation apparatus of Methanococcus jannaschii possesses the unusual enzyme prolyl-cysteinyl-tRNA synthetase (ProCysRS), a single enzyme that attaches two different amino acids, proline and cysteine, to their cognate tRNA species. Measurement of the ATP-PP(i) exchange reaction revealed that amino acid activation, the first reaction step, differs for the two amino acids. While Pro-AMP can be formed in the absence of tRNA, Cys-AMP synthesis is tRNA-dependent. Studies with purified tRNAs indicate that tRNA(Cys) promotes cysteine activation. The k(cat) values of wild-type ProCysRS for tRNA prolylation (0.09 s(-1)) and cysteinylation (0.02 s(-1)) demonstrate that both aminoacyl-tRNAs are synthesized with comparable rates, the cysteinyl-tRNA synthetase activity being only 4.5-fold lower than prolyl-tRNA synthetase activity. Kinetic analysis of ProCysRS mutant enzymes, generated by site-directed mutagenesis, shows glutamate at position 103 to be critical for proline binding, and proline at position 100 to be involved in cysteine binding. The proximity in ProCysRS of amino acid residues affecting binding of either cysteine or proline strongly suggests that structural elements of the two amino acid binding sites overlap.

Acylation↗
PubMed2001

[Network of surgical wound centers using a new electronic data processing documentation system].

UNLABELLED: Care of chronic wounds is of enormous medical, social and economic importance. Nevertheless there is a lack of epidemiological and economical data. A network of ten wound care centers was created and data were documented in a new computerized wound documentation system. METHODS: Treatment was performed according to a comprehensive and standardized wound care protocol. The new documentation system is a network-capable solution. Digital images and planimetry as well as patient and wound related data are recorded. RESULTS: During the first year the ten centers treated and documented already 3281 wounds. There is a wide spectrum of different chronic wounds treated in the participating centers. Despite of long wound duration of several wounds with a median of 5 weeks (range 0-62 years), the healing rate was 80% within 455 days. CONCLUSION: Large amounts of data can be collected and scientifically evaluated in the wound net. This is realized by a new computerized documentation system, which was integrated into the clinical routine and enables clear and standardized documentation. Therefore even large multicenter therapy studies may be performed easily in the wound net and economical data could be collected.

Chronic Disease↗
PubMed2001

[Endobronchial juvenile hemangioma in infancy--removal by main bronchus cuff resection. Case report].

The rare case of a 3.5 month-old infant diagnosed with a endobronchial haemangioma is presented and discussed against a background of reference literary material. A main-bronchus sleeve resection with end-to-end anastomosis was performed without reduction of lung parenchyma. No complications were documented during the period of observation. The results of repeated bronchoscopy showed the post-operative period to be of a non-problematic nature.

Bronchi↗
PubMed2001

[Proliferation rate of small cell lung carcinoma. A cytomorphometric parameter with prognostic significance].

AIM: Evaluation of prognosis-associated parameters in patients with small cell lung carcinoma. MATERIAL AND METHODS: Biopsies of 46 patients suffering from a non-treated small cell lung carcinoma were stained with Feulgen and immunohistochemically with Ki-67 antibody. The integrated optical density (IOD) and proliferation rate was measured by syntactic structure analysis and correlated with survival. RESULTS: About 85% of patients had a smoking history (46 pack years on average). The median survival time was 13.5 months, the proliferation rate (Ki-67 positive tumor cell nuclei) 68.2% and S-phase percentage 9.2%. Ot average, 25 proliferating tumor cell nuclei formed clusters (mean diameter 95 microns). The prognosis was associated with the proliferation rate (p < 0.04), tumor stage (stage I versus lib, p < 0.05), at threshold limits with S-phase rate (p < 0.07) and serum levels of LDH and NSE (p < 0.06 and p < 0.07 respectively). CONCLUSIONS: Immune histochemical determination of the Ki-67 protein is a useful method to estimate the prognosis of patients with small cell lung carcinoma.

Antigens, Neoplasm↗
PubMed2001

Intraperitoneal capsaicin treatment reduces postoperative gastric ileus in awake rats.

INTRODUCTION: Postoperative gastric ileus interferes with postoperative recovery of the patients. Previous studies suggest that capsaicin-sensitive afferent neurons are involved in the mediation of postoperative gastric ileus. METHODS: A group of rats were equipped with a strain gauge transducer sutured to the gastric wall. Gastric motility was recorded after intraperitoneal injection of capsaicin (0.1 micromol/kg and 1 micromol/kg) or vehicle. The rats were given 2 days of recovery before gastric motility was investigated in a postoperative ileus model. RESULTS: Pretreatment with capsaicin 2 days prior to abdominal surgery significantly increased postoperative gastric motility, with complete recovery of gastric motility at 30 min postoperatively (with the baseline motility index set at 100+/-4%, the gastric motility index 30-45 min postoperatively was 64+/-4% for the vehicle, 138+/-20% for capsaicin 0.1 micromol/kg, and 110+/-12% for capsaicin 1 micromol/kg: P=0.0008 vehicle vs capsaicin). In contrast, capsaicin treatment 2 h prior to abdominal surgery did not increase postoperative gastric motility (gastric motility index 30-45 min postoperatively was 64+/-4% for the vehicle and 51+/-8% for capsaicin 0.1 micromol/kg). The acute intraperitoneal injection of capsaicin decreased gastric motility by about 50-60%, the response lasting for 15-30 min. CONCLUSIONS: Intraperitoneal capsaicin treatment 2 days prior to abdominal surgery resulted in immediate recovery of postoperative gastric motility, indicating an important role for serosal visceral afferent nerve fibers in the mediation of postoperative gastric ileus. Possibly, capsaicin or vanilloid (capsaicin) receptor agonists can be used to treat postoperative ileus in the future.

Animals↗
PubMed2001

Endobronchial ultrasound.

Endobronchial ultrasound (EBUS) is a new diagnostic tool, which has expanded the view of the bronchoscopist beyond the confinements of the airways. It has great potential for diagnosis of mediastinal processes and staging of lung cancer. These will be discussed and illustrated. EBUS will become a superior tool for staging of lung cancer, and several comparative studies on EBUS as compared with standard techniques in order to assess its role in the staging procedure are just on their way or already completed.

Endosonography↗
PubMed2001

Bronchoscopy. Year 2001 and beyond.

The current revolution in technology, imaging, and information processing will be of major influence on bronchoscopy within the next two decades. Clinicians will be able to visualize structures in vivo that up to now only the pathologist could see. Clinicians will reach anatomic structures that are inaccessible by the bronchoscope, yet treat diseases that are still the domain of surgeons, medical oncologists, and radiotherapists. Clinicians will be able to communicate online worldwide, improving standards of patient care, teaching, and finally even perform interventional procedures by way of networks. Because of the exponential growth of sciences like nanotechnology and biotechnology, these changes will come very rapidly. The new quality of these intelligent instruments will demand a new ideological and ethical discourse on the future of science in general.

Bronchoscopes↗
PubMed2001

Documentation in bronchology.

With the performance of more endoscopic procedures and newly developed diagnostic and therapeutic modalities, a wealth of information around the actual procedure is created. To date, accepted guidelines for standardized documentation are lacking. The authors present recommendations for minimal guidelines that may help to facilitate good documentation and also address future developments that will be possible with the help of computer-assisted approaches.

Bronchoscopy↗
PubMed2001

Functional T lymphocytes infiltrate implanted polyvinyl alcohol foams during surgical wound closure therapy.

Vacuum-assisted closure involving the implantation of polyvinyl alcohol foam is a technique recently developed for the treatment of patients suffering from either wound infection or chronic wounds. This method has been shown to improve and accelerate wound healing. However, little is known about the cell populations that infiltrate the foam, and their potential role in resolving the infection and promoting granulation tissue formation. Our study demonstrates that wound-implanted foams are mainly infiltrated with granulocytes, but that mononuclear cells, including macrophages and minor populations of T, B and natural killer lymphocytes, are also present. We show that foam-infiltrating T cells, especially CD4(+) T cells, constitute a phenotypically and functionally heterogeneous population influenced by wound-infecting bacteria. Thus, T lymphocytes could play a role in wound cleansing. In addition, our data indicate that implanted polyvinyl alcohol foams might be suitable microenvironments for manipulating T cell-mediated immune responses in patients.

Adult↗