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Biomedical subjects

T Benter

Publications and source records attributed to T Benter.

At least 19 recordsLinked to original sources
PubMed2006

[Ultrasound education by simulator training high acceptance by ultrasound trainees of all qualification levels].

Ultrasound education improves by simulator training, however, the acceptance of ultrasound simulator training has not been investigated. Therefore we evaluated the participants response to simulator education during an ultrasound course of abdominal emergencies at an international ultrasound congress, at a regular ultrasound course and during courses at a regional hospital and an university hospital. Altogether, 62.3% of the participants judged the simulator image quality to be good. 84.3% considered the case selection to be good and 92.7% of the participants viewed the educational benefit to be good. 98.5% whished to have further ultrasound simulator courses to be developed and 95.3% of the participants opted for the integration of simulator training into the conventional ultrasound education.

Attitude of Health Personnel↗
PubMed2004

[Long-term central venous lines and their complications].

The implantation of permanent (> 14 days) central venous catheters is constantly increasing, accelerated by a trend toward outpatient therapies. Subcutaneous tunneled and non-tunneled catheters as well as port systems are available. The interventional radiologist plays an important role in the implantation of central venous catheters as well as in detection and treatment of any complications. Various access ways via peripheral and central veins are described and the implantation techniques for the different systems explained. The use of peel-away sheaths allows the radiologist to implant subcutaneous tunneled catheters via the Seldinger technique without surgical preparation. Procedure-related early and late complications may occur, and the radiologist plays an important role in the surveillance and management of catheter-associated complications. This review demonstrates the different catheter systems and implantation techniques.

Catheterization, Central Venous↗
PubMed2003

[Accuracy of the sonographic determination of the splenic weight in comparison with the weight at autopsy].

PURPOSE: The weight of the spleen can be easily calculated from sonographic measurements. This study investigates the correlations between the weight of the spleen determined sonographically and the weight measured at autopsy or after splenectomy. MATERIALS AND METHODS: The splenic weight at autopsy or after splenectomy was correlated with the calculated sonographic splenic weight in 55 patients who had a sonographic examination within the preceding three weeks. RESULTS: A significant correlation (r = 0.978) was found between the sonographically calculated splenic weight (460.82 grams) and the measured weight of the removed spleen (average weight 463.18 grams). Spleens weighing more than 1 kg showed a slightly weaker correlation. CONCLUSION: This study proves that the simple formula of length x transverse diameter x vertical diameter x 0.6 provides a reliable calculation of the weight of the spleen.

Autopsy↗
PubMed2001

Hydrogen sensors and switches from electrodeposited palladium mesowire arrays.

Hydrogen sensors and hydrogen-activated switches were fabricated from arrays of mesoscopic palladium wires. These palladium "mesowire" arrays were prepared by electrodeposition onto graphite surfaces and were transferred onto a cyanoacrylate film. Exposure to hydrogen gas caused a rapid (less than 75 milliseconds) reversible decrease in the resistance of the array that correlated with the hydrogen concentration over a range from 2 to 10%. The sensor response appears to involve the closing of nanoscopic gaps or "break junctions" in wires caused by the dilation of palladium grains undergoing hydrogen absorption. Wire arrays in which all wires possessed nanoscopic gaps reverted to open circuits in the absence of hydrogen gas.

Journal Article↗
PubMed2001

Selective ultra-trace detection of NO and NO2 in complex gas mixtures using broad-bandwidth REMPI mass spectrometry.

In this paper we demonstrate the feasibility of ultra-trace resonance enhanced multiphoton ionization (REMPI) detection employing a small broad-bandwidth solid state laser system. The results reported here are compared with measurements carried out with a conventional excimer pumped dye laser combination. Mass selected broad-bandwidth REMPI spectra for the environmentally relevant nitrogen oxides NO and NO2 are presented. Tunable broad-bandwidth laser radiation with a spectral resolution of > 10 cm(-1) in the wavelength range 560-400 nm was employed for the detection of NO2. For NO detection, the range 230-224 nm was covered. Laser radiation was generated using an optical parametric oscillator pumped by an unseeded Nd:YAG laser. A mobile time-of-flight mass spectrometer equipped with an atmospheric pressure laser ionization source allowed for mass selective parent ion detection at m/z 30 for NO and m/z 46 for NO2. The limit of detection was 10 pptV for NO and 20 pptV for NO2. A selectivity of > 2000 for both compounds with respect to N2O5, organic nitrates and NO2 in the case of NO is reported. An improved laser system currently under construction is expected to provide detection limits below pptv mixing ratios for both nitrogen oxides in a 20 s integration interval.

Environmental Pollutants↗
PubMed2001

Anatomical variations in the internal jugular veins of cancer patients affecting central venous access. Anatomical variation of the internal jugular vein.

PURPOSE: Establishing a reliable central venous access is an important procedure in clinical haematology and oncology. The purpose of this study was to determine how anatomical variations in the internal jugular vein (IJV) and its position in relation to the common carotid artery (CCA) in cancer patients affects external landmark puncture. PATIENTS AND METHODS: In 113 patients with haematological or oncological diseases we examined sonographically potential target regions for placement of a central catheter via the IJV. RESULTS: 36% of our patients showed anatomical variations in the IJV and surrounding tissue. CONCLUSIONS: External landmark puncture may be difficult in a considerable number of patients since the IJV might not be situated in the presumed location anteriorly or laterally to the CCA, or a normal lumen may not be present in approximately 1/3 of cancer patients. This study supports the use of ultrasound-guided techniques for central venous catheters particularly in haematological and oncological patients.

Adult↗
PubMed2000

A REMPI method for the ultrasensitive detection of NO and NO2 using atmospheric pressure laser ionization mass spectrometry.

We report on the development of a quasi-simultaneous highly selective method for NO and NO2 detection at the ultratrace level. Atmospheric pressure laser ionization (APLI), recently introduced by our group, is used to detect both compounds at low parts per trillion by volume (pptv) mixing ratios. APLI is based on resonance-enhanced multiphoton ionization mass spectrometry. Two-color pump-probe experiments employing a single excimer pumped dye laser combination allow for the ultrasensitive measurement of NO and NO2 within a narrow range of maximum pumping efficiency of the laser dye Coumarin 120. NO is detected via excitation of the long-lived A 2sigma+ (nu' = 1) level at 215.36 nm and subsequently ionized with 308-nm radiation provided by the excimer pump laser. NO2 is ionized after double resonant excitation of the A2B1 and 3psigma manifolds in a (1 + 1' + 1(')) process using 431.65 + 308 nm. The selectivity of the NO measurement exceeds 2,000 with respect to NO2 and N2O5. For NO2, a selectivity of >3,000 with respect to N2O5 and organic nitrates is observed. The current APLI detection limit of NO and NO2 is 0.5 and 5 pptv, respectively, with a 20-s integration time.

Journal Article↗
PubMed2000

Impaired BAX protein expression in breast cancer: mutational analysis of the BAX and the p53 gene.

We have previously shown that the pro-apoptotic BAX protein is differentially expressed in breast cancer and in other epithelial tumors. In this line, a reduced BAX protein expression is a negative prognostic factor in various carcinomas including breast cancer. For p53, a trancriptional activator of BAX in apoptosis, mutations in the coding sequence were shown to modulate BAX protein expression in cell line models on the transcriptional level. We therefore investigated the BAX gene in 68 breast cancer specimens for the presence of mutations in the coding sequence by single-strand conformation polymorphism (SSCP)-PCR and direct sequencing. The expression of BAX protein was assessed by immunohistochemistry. In addition, we screened for mutations in the exons 5-8 of the p53 gene by SSCP-PCR to assess whether mutations in the DNA-binding domain of this upstream regulator of BAX gene transcription are responsible for differences in BAX protein expression. As previously observed, BAX was differentially expressed in the breast cancer samples, but no mutations in the coding sequence of the BAX gene were found besides a polymorphism in exon 6 at the position 552 (G->A) and additional intronic polymorphisms. In contrast, we identified 16 of 68 (23.5%) tumors to bear mutations in the p53 gene. In the subset of BAX-expressing tumors, the mutational inactivation of p53 did result in a reduced BAX protein expression (Fisher exact test, p = 0. 047). Nevertheless, we identified a subset of BAX-negative tumors lacking BAX or p53 mutations. Thus, additional, not yet identified regulators, apart from p53, appear to be involved in the regulation of BAX protein expression.

Base Sequence↗
PubMed2000

[Ultrasonographically guided puncture technique for central venous vessels as a one-person technique].

AIM: The traditional anatomic landmark technique usually allows a rapid and easy central venous access but this technique is not always successful and can be associated with severe complications. We developed an ultrasonically guided one-operator-catheterization technique whereas a second operator to place and hold the ultrasound transducer is not necessary. METHOD: The catheterisation technique consists of 3 functional components: the swivel arm, the ultrasound unit and the conventional Seldinger central venous catheterization technique. As swivel arm we used a device with a 300 mm column with a 700 mm span attached to ultrasound unit. There were 234 catheterizations of the internal jugular vein performed in the period of January 1999 to July 1999. The indication and complication rate for the catheterization procedure was documented. RESULTS: There were 2 plexus irritations and 1 hematoma observed in all performed catheterization procedures which remained without therapeutic consequences. CONCLUSION: Once the decision for central venous access has been made the safest technique should be applied. The ultrasonically guided catheterization technique allows a fast, safe and convenient central venous access for our patients.

Catheterization, Central Venous↗
PubMed2000

Weekly 24-hour infusion of high-dose 5-fluorouracil plus folinic acid in combination with mitomycin C for the treatment of advanced gastric cancer.

PURPOSE: This study was performed to investigate the activity and safety of high dose 5-fluorouracil (5-FU) given as a weekly 24-hour infusion in combination with folinic acid plus mitomycin C in patients with advanced gastric cancer. PATIENTS AND METHODS: Chemonaive patients with locally advanced inoperable, recurrent or metastatic gastric cancer were treated with 15 mg/m(2) i.v. mitomycin C as bolus on day 1 of a 7-week cycle followed by a 2-hour infusion of folinic acid (500 mg/m(2)) and a 24-hour infusion of 5-FU (2,600 mg/m(2)) given on days 1, 8, 15, 22, 29, and 36 as outpatient treatment. RESULTS: Thirty evaluable patients (median age 58 years and median ECOG performance status 1) received 1-4 cycles (median 3). 53% of the patients had liver metastases. Treatment-related toxicity was low with 10% of patients experiencing diarrhea >/=grade 3, 3% mucositis grade 3 and 3% nausea grade 3 (CTC). Hematological toxicity was mild with 13% thrombopenia grade 3 and no leukopenia grade 4. Eleven patients achieved a partial remission (major response rate 37%; 95% confidence interval 22-53%). Median time to progression was 5 months and median overall survival time was 7 months. CONCLUSION: This regimen is a well-tolerated outpatient treatment for patients with advanced gastric cancer with efficacy being comparable to other chemotherapy protocols.

Adolescent↗
PubMed1999

[Project graph technique for time management in abdominal ultrasound evaluations].

PURPOSE: German insurance companies are cutting down the time required for ultrasound examinations. To determine the minimal examination time to perform an ultrasound examination a project graph technique was applied. MATERIALS AND METHODS: Time measurements of abdominal ultrasound examinations were performed by two independent observers. The different jobs for the performance of an ultrasound examination were determined and the critical pathway method applied. The total available time for abdominal ultrasound examinations (leeway) was determined, the minimal time to perform each job was measured and the critical time required for the procedure was calculated. RESULTS: 14 different jobs were identified to complete one abdominal ultrasound examination. The project graph displayed the shortest possible time of 24 minutes to perform an ultrasound examination. The pure ultrasound exam without colour Doppler examination was 6 minutes ("hands on the ultrasound probe"). The jobs performed by the physician were fully within the critical period. In consequence, the physician had no leeway or time lag in relation to a total time of 24 minutes for an ultrasound examination, whereas by contrast the nurse has a total leeway of 7.5 minutes. CONCLUSIONS: The applied project graph technique is an effective instrument for the purpose of quality management for hospitals as well as in private practice. The workflow and actions necessary to perform a treatment or examination can be analysed. Human resources management and cost planning should be performed on the basis of project graphs.

Abdomen↗
PubMed1998

Raltitrexed (Tomudex): an alternative drug for patients with colorectal cancer and 5-fluorouracil associated cardiotoxicity.

Two patients with proven 5-fluorouracil (5-FU)-associated cardiotoxicity were treated with the specific thymidylate synthase inhibitor raltitrexed safely, without evidence of cardiotoxicity. Raltitrexed might be an alternative for patients with advanced colorectal cancer and 5-FU-associated cardiotoxicity. 5-FU cardiotoxicity is not due to the antineoplastic mechanisms via thymidilate synthase.

Adenocarcinoma↗