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Biomedical subjects

R Trapp

Publications and source records attributed to R Trapp.

11 recordsLinked to original sources
PubMed2006

Successful maintenance of continuous ambulatory peritoneal dialysis in a patient after fungal peritonitis and dialysate leakage.

Fungal peritonitis (FP) and dialysate leakage have often been reported in association with continuous ambulatory peritoneal dialysis (CAPD), which has to be discontinued in many cases due to these complications. This report describes the first case of dialysate leakage into the urinary bladder of a 70-year-old male patient, after the area of the left ureteral ostium had been very deeply resected. The leakage probably led to severe fungal peritonitis developing 1 day after the ostium resection. The ostium resection was performed in November 2003 after detection of a carcinoma in situ (Cis) in this area and after previous bilateral nephroureterectomies due to multifocal urothelial carcinoma in the kidneys, ureters and bladder. In spite of prior fungal peritonitis and dialysate leakage, CAPD could be successfully initiated 41 days after biochemical manifestation of peritonitis and could be maintained in the patient because of the following reasons: early and effective treatment of FP with fluconazole and voriconazole, spontaneous occlusion of the slitted ostium area, allowance of enough healing time after 2 major abdominal surgeries, during which the patient was placed on extracorporal hemodialysis (which had been started 1 day after nephroureterectomy and ended after the antimycotic treatment) and thorough monitoring of the patient after starting CAPD. In January 2004, the patient could be placed on a cycler peritoneal dialysis and was fully rehabilitated 1 year later.

Aged↗
PubMed1996

Tactile optical sensor for use in minimal invasive surgery.

In minimal invasive surgery high sensory palpation of the organs is largely lost. It is the purpose of this work to recover tactile sensing for the surgeon. To achieve this goal, a new tactile optical pressure sensor has been developed which allows to display 64 measuring points on a 0.64 cm2 surface area with a digital resolution of 12 bits. The sensor has been conceived for application in laparoscopic grasping forceps and can also be integrated into a sensing rod, both 15 mm in outside diameter. This optical sensor allows us to display graphically indurations spread in the tissue. Furthermore, the measured values serve to activate a vibrotactile display unit for tactile feedback onto the surgeon's fingertip. In order to obtain further information about the requirements for an analog tactile display, an actuatorarray with 144 pins on a 4 cm2 surface area was built. The array allows various test objects to be recognized in a true scale presentation by exploratory movements of the fingers.

Computer Graphics↗
PubMed1993

Kinematic problems of manipulators for minimal invasive surgery.

The article discusses handling problems in endoscopic surgery and concepts for the augmentation of instrument dexterity. The authors present a kinematic concept for improved surgical tool positioning and orientation. Using a trunk mechanism it is possible to assure augmented dexterity and stiffness for endoscopic handling. The paper addresses the use of steerable endoscopic instruments in a manipulator system for minimal invasive surgery.

Biomechanical Phenomena↗
PubMed1991

[Color-coded Doppler ultrasonography in early detection of rejection reactions after allogeneic kidney transplantation].

A prospective study of 45 consecutive patients (27 men, 18 women, mean age 42 [22-64] years) who had undergone allogeneic renal transplantation was carried out to ascertain whether rejection of the graft can be detected by routine follow up with colour-coded Doppler ultrasonography even in the presence of acute renal failure requiring dialysis. Conventional diagnostic methods detected 44 episodes of rejection in 33 patients: 26 of these arose in 18 patients with acute renal failure requiring dialysis and 18 in 15 patients who did not require dialysis. Colour-coded Doppler ultrasonography was used to determine the "pulsatility index" (PI) at intervals of 3 to 6 days. 17 of the 18 episodes of rejection occurring in transplant patients with stable serum creatinine levels (3.41 +/- 1.48 mg/dl) were detected by colour-coded Doppler ultrasonography 3.8 +/- 5.6 days earlier than by conventional diagnostic methods, the indicator being the rise in PI (sensitivity 93.8%). 25 of the 26 rejection reactions which arose in patients with oligo-anuria due to post-operative renal failure were detected 2.0 +/- 2.7 days earlier (sensitivity 96%). The rise in PI was greater in episodes of vascular rejection than in purely interstitial rejection episodes (40.9 +/- 73.9% versus 10.0 +/- 8.8% per day). Colour-coded Doppler ultrasonography ia a new, highly sensitive, noninvasive method for the early detection of rejection reactions after renal transplantation. Acute postischaemic renal failure does not reduce its sensitivity.

Acute Kidney Injury↗
PubMed1988

Analysis of the phosphofructokinase subunits and isoenzymes in human tissues.

The 6-phosphofructo-1-kinase (PFK) subunits and isoenzymes were studied in human muscle, heart, brain, liver, platelets, fibroblasts, erythrocytes, placenta and umbilical cord. In each tissue, the subunit types in the native isoenzymes were characterized by immunological titration with subunit-specific antibodies and by column chromatography on QAE (quaternary aminoethyl)-Sephadex. Further, the subunits of the partially purified native isoenzymes were resolved by SDS/polyacrylamide-gel electrophoresis, identified by immunoblotting, and quantified by scanning gel densitometry of silver-stained gels and immunoblots. Depending on the type of tissue, one to three subunits were detected. The Mr values of the L, M and C subunits regardless of tissue were 76,700 +/- 1400, 82,500 +/- 1640 and 86,500 +/- 1620. Of the tissues studied, only the muscle PFK isoenzymes exhibited one subunit, which was the M-type subunit. Of the other tissues studied, the PFK isoenzymes contained various amounts of all three subunits. Considering the properties of the native PFK isoenzymes, it is clear that, in human tissues, they are not simply various combinations of two or three homotetrameric isoenzymes, but complex mixtures of homotetramers and heterotetramers. The kinetic/regulatory properties of the various isoenzyme pools were found to be dependent on subunit composition.

Adenosine Triphosphate↗
PubMed1982

The single erythrocyte rigidometer (SER) as a reference for RBC deformability.

The SER allows the "deformability" of individual red blood cells to be quantitated by determining their passage time through a pore (d = 5.8 microns, 1 = 50 microns) under the shear stresses of 1.5 Pa-4 Pa. Using this system, we examined the influence of: 1. cytoplasmic viscosity, 2. membrane viscoelastic properties, 3. area to volume relationship. To change these determinants of RBC-deformability, the cells have been altered with 1. Acetylphenylhydrazine (0.016 mol/l), 2. diamide (0.5 mmol/l), 3. osmotic swelling (200 mosm/l) and osmotic shrinking (480 mosm/l) by suspending the cells in hypo- and hypertonic saline. The passage time has been found to be primarily influenced by changes in cytoplasmic viscosity. The same cells when tested in 4 other systems considered to measure RBC-deformability (filtrometer, packed cell viscometry, rheoscope and ektacytometry) behaved differently.

Blood Viscosity↗
PubMedDate not supplied

Comparison of the efficacy and safety of oxaprozin and nabumetone in the treatment of patients with osteoarthritis of the knee.

This multicenter, 6-week, double-blind, placebo-controlled, parallel-group study compared the efficacy and safety of oxaprozin 1200 mg once daily with that of nabumetone 1000 mg once daily in patients with moderate-to-severe osteoarthritis (OA) of the knee. To be eligible, patients had to experience a flare of OA within 2 weeks of discontinuing their usual OA medication (nonsteroidal anti-inflammatory drug or analgesic). Eligible patients were assessed at baseline and then randomized to receive oxaprozin (n = 109), nabumetone (n = 110), or placebo (n = 109). Efficacy assessments were performed at weeks 1, 2, 4, and 6. Primary efficacy variables included knee pain on weight bearing, knee pain on motion, and patient's and physician's global assessments of OA. Secondary efficacy variables included pain intensity, time to walk 50 feet, and duration of morning stiffness. Safety was evaluated by use of routine laboratory analyses; physical examination at screening, baseline, and week 6 (or study termination); assessment of symptoms at baseline and at each visit; and testing stools for occult blood at screening and between week 4 and the final visit. Adverse events were monitored throughout the study. Between-group differences in efficacy variables were evident by week 1. The mean change in improvement from baseline with oxaprozin compared with placebo was statistically significant in favor of oxaprozin at weeks 1, 2, 4, and 6 for all primary efficacy variables. The mean change in improvement from baseline with nabumetone compared with placebo, however, was statistically significant only at week 1 for knee pain on motion, patient's global assessment, and physician's global assessment. The mean change in improvement from baseline was statistically significant (P < or = 0.035) in favor of oxaprozin versus nabumetone at weeks 2 and 6 for all four primary efficacy variables and also at week 4 for knee pain on motion. The incidence of adverse clinical events between treatment groups was not statistically significant. However, nine oxaprozin-treated patients had asymptomatic liver enzyme elevations reported as adverse events. Four of these patients had reversible elevations of aspartate aminotransferase and alanine aminotransferase greater than three times the upper limit of normal range (P < 0.05); two of these patients were taking other medications known to induce liver enzyme abnormalities. The study showed that oxaprozin 1200 mg once daily was statistically significantly more efficacious than nabumetone 1000 mg once daily for the treatment of patients with moderate-to-severe OA of the knee. Both drugs were clinically well tolerated.

Aged↗
PubMedDate not supplied

The efficacy, tolerability, and safety of 1200 mg/d of oxaprozin and 1500 mg/d of nabumetone in the treatment of patients with osteoarthritis of the knee.

This 6-week, multicenter, double-masked, placebo-controlled study compared the efficacy, tolerability, and safety of the recommended starting dose of oxaprozin (1200 mg/d) and a 1500-mg/d dose of nabumetone in the treatment of patients with moderate-to-severe osteoarthritis (OA) of the knee. A total of 347 patients with a mean age of 61.1 years were randomized to receive oxaprozin (116 patients), nabumetone (115 patients), or placebo (116 patients). Adults of either sex who were older than 18 years of age were eligible for entry into the study, if they had had OA of the knee for at least 6 months. Efficacy variables included knee pain on weight bearing, knee pain on motion, patients' and physicians' global assessments of OA, pain intensity as measured on a visual analog scale, and time to walk 50 feet as quickly as possible. Efficacy variables were assessed at baseline and at weeks 1, 2, 4, and 6. Between-group differences in efficacy variables were evident by week 1. Mean improvements were significantly greater with oxaprozin than with placebo for all efficacy variables at all time periods, except knee pain on motion at weeks 2 and 4 and time to walk 50 feet at weeks 1, 2, and 4. Mean improvements were significantly greater with nabumetone than with placebo for all efficacy variables at all time periods, except the following: knee pain on weight bearing at weeks 2, 4 and 6; knee pain on motion at weeks 2 and 4; patients' global assessment at week 4; and pain intensity as measured on a visual analog scale at weeks 2 and 4. There were, however, no significant differences between oxaprozin and nabumetone in any of these efficacy variables. Adverse events were reported by 83 (71.6%) patients who took oxaprozin, by 80 (69.6%) patients who took nabumetone, and by 57 (49.1%) patients who took placebo. Adverse events were reported for significantly more patients taking oxaprozin or nabumetone than placebo. However, adverse events tended to be mild or moderate and rarely resulted in patients withdrawing from the study. Combined with the results of an earlier study, the results of this study showed that a 1500-mg/d dose of nabumetone, which is higher than the recommended starting dose of 1000 mg/d, is required for efficacy equivalent to that of the recommended starting dose of oxaprozin, 1200 mg/d, in relieving the symptoms of OA. Thus nabumetone may require dosage titration from the recommended starting dose. Oxaprozin and nabumetone were found to have similar tolerability profiles, as shown by adverse-event monitoring and withdrawal rates, as well as clinically similar safety profiles, as demonstrated by physical examinations, hematologic and biochemical laboratory testing, hemoccult testing, and adverse-event monitoring and symptom assessment.

Adult↗
PubMedDate not supplied

Histologic effects of different technologies for dissection in endoscopic surgery: Nd:YAG laser, high frequency and water-jet.

Precise cutting combined with reliable coagulation of the margins of the lesion is an important requirement for dissection techniques in endoscopic surgery. These requirements are met by the two most common ancillary energy sources applied for endoscopic dissection today, electrosurgery and "thermal lasers", mostly the Nd:YAG. For the comparison of the histological effects of monopolar and bipolar high frequency with the Nd:YAG laser an experimental in vitro and in vivo study has been performed. In order to evaluate the advantages of non thermal dissection for endoscopic procedures, a water jet cutting system was included in the in vitro study. In parenchymatous tissue the water jet was found to be the least traumatic technique, followed by bipolar high frequency, laser and monopolar high frequency. The water jet was not applicable for intestinal dissection since uncontrolled bloating of the rectal wall with uncontrolled disruption of the tissue layers occurred. A general disadvantage is that secure haemostasis in the line of incision is hard to achieve. In the microscopic comparison of the shape of the incision, the Nd:YAG laser produced the smoothest lesions with well-defined margins. The monopolar technique was more often associated with irregular and sometimes fissured margins. These results were confirmed in the in vivo part of the study (Transanal Endoscopic Microsurgery).

Animals↗
PubMedDate not supplied

Development of steerable instruments for minimal invasive surgery in modular conception.

The augmenting complexity of minimal invasive interventions requests a continuous improvement of technologies. Extended endoscopic procedures, e.g. laparoscopic-transanal sigmoidectomy or thoracoscopic esophagus dissection require difficult surgical manipulations like mobilisation, sceletonization as well as ligatures and sutures. They are difficult to perform with the present endo-surgical instruments. A major instrumental weakness is represented by the restricted steerability because of the rigid shaft axis and the resulting low degrees of freedom (DOF). Therefore a series of steerable flexible instruments has been developed in interdisciplinary cooperation between surgeons and engineers. The prototypes provide a multi-joint working as the instrument's elbow, which allows to incline the tip around +/- 280 degrees. The second additional DOF is the rotation of the surgical tool. The prototypes have been experimentally tested in laparoscopy and thoracoscopy, showing a clear improvement in the carrying out of complex operative manipulations. The further development is performed in modular conception, including electric drives.

Animals↗