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Biomedical subjects

C Ell

Publications and source records attributed to C Ell.

At least 73 records · Page 4Linked to original sources
PubMed1996

Biophysical effects of high-energy pulsed ultrasound on human cells.

Human benign and malignant cells of different human origin (pancreas, liver, kidney, pharynx, tongue, lip) were exposed to high-energy pulsed ultrasound (HEPUS) in vitro to evaluate the effects of various physical parameters and sonication conditions on cell viability. This included the number of pulses, focal pressure, pulse repetition rate, pulse shape, cell suspension volume, water level of the basin and cell density. Cell viability was found to depend significantly on the number of pulses (exponential), the focal pressure (linear) and the pulse repetition rate (minimum at 1 Hz). Other parameters showed no marked influence. Furthermore, electron microscopy revealed intracellular damage, and proliferation rates of cells surviving sonication were normal after HEPUS exposure. The experimental piezoelectric ultrasound transducer used in the experiments generated oscillating bipolar pulses with high negative pressure amplitudes. Measurements were made of the pulse shape and ultrasonic field of the experimental device and of a conventional lithotripter for comparison.

Biopsy↗
PubMed1996

Colon decompression using an anatomically adapted, large-caliber decompression probe.

Intestinal pseudo-obstruction, paralytic (e.g. postoperative or drug-induced) hyperdistension of the large bowel and colonic stenosis often require endoscopic decompression. The decompression probes currently available have the disadvantage of an insufficiently large diameter or inadequate adaptation to the given anatomic configuration of colon, or both. A new decompression probe system consisting of a guide wire, a 12-Fr polyethylene guide catheter, and a 24-Fr polyurethane decompression probe, is presented and two cases are described. The probe was tested in a pilot study in 16 patients. In all patients, implantation was successfully performed without complications. No undesired dislocation was observed. The introduction time varied between four and 16 minutes. Clinically successful decompression was achieved in 14 of the 16 patients.

Aged↗
PubMed1996

Self-expanding metal stents for palliation of malignant obstruction in the upper gastrointestinal tract. Comparative assessment of three stent types implemented in 96 implantations.

Self-expanding metal stents provide a new option for the palliative treatment of malignant stenoses from tumors of the esophagus. Our present study provides a comparative assessment of clinical experience gained consecutively in the implementation of three stent versions in a total of 87 patients and 96 implantations. Thirty-one Wallstents (Scheider, Lusanne, Switzerland) (five coated) were implanted in 23 patients, 35 Ultraflex stents (Boston Scientific, Boston, MA, U.S.A.) (uncoated) in another 34 patients, and 30 Gianturco-Z stents (Cook, Winston-Salem, NC, U.S.A.) (all coated) in a group of 30 patients. In the three patient groups there were no significant differences as to the degree of dysphagia, number of pretreatments, length of the tumor stenosis, tumor location, or histological classification. Seven patients who had been treated with Gianturco-Z stents presented with an esophagorespiratory fistula. Technically, all 96 implantation procedures were successful. Complete sealing of the fistulas was verified by radiography in all patients who had developed fistulas. Severe early complications in the form of stent migration were encountered in only three of 96 implantations (3%). Within the early period after stent placement in five patients of the Wallstent group (22%), 13 patients of the Ultraflex group (37%), and three patients of the Gianturco group (10%), retreatments were necessary due to stent dislocation and/or insufficient stent expansion. The degree of dysphagia improved distinctly and with a comparable development in all three patient groups. The rate of reintervention (percentage of patients) due to major and minor problems in the follow-up period amounted to 43% (Wallstents), 35% (Ultraflex stents), and 21% (Gianturco-Z stents). In view of the low number of complications (3%) in the early stage of implantation, self-expanding metal stents provide an improved approach for palliative therapy of malignant stenoses of the esophagus. Nevertheless, further technological improvements are necessary to reduce the great frequency of unavoidable reinterventions (20-43%) in the follow-up period.

Adult↗
PubMed1996

Correlation of polypoid lesions in the distal colorectum and proximal colon in asymptomatic screening subjects.

OBJECTIVE: Knowledge of a possible correlation between distal polyps found at screening sigmoidoscopy and proximal colonic lesions is important for deciding whether to perform total colonoscopy or not. PATIENTS: A prospective analysis of 2439 consecutive patients with colorectal polyps. Of these, 304 were asymptomatic subjects who underwent complete colonoscopy for screening and were found to have adenomatous or hyperplastic polyps in the distal colorectum. RESULTS: Ten (15%) out of 65 patients with distal hyperplastic polyps only and 86 (36%) out of 239 with distal adenomatous polyps were found to have adenomatous polyps in the proximal colon as well (P < 0.001). The frequency of synchronous proximal adenomas in patients with small (< or = 5 mm) or large distal adenomas (> 5 mm) was comparable (37% and 35%, respectively). However, patients with small distal adenomas had significantly smaller proximal adenomas (P = 0.004) containing less villous component (P = 0.017) than those with large distal adenomas. Neither the patient's age nor the presence of multiple distal adenomas increased the prevalence of proximal adenomas. CONCLUSION: Hyperplastic polyps found on rectosigmoidoscopy do not indicate a need for a complete colorectal examination, as 15% of patients with distal hyperplastic polyps will have proximal adenomatous polyps, a figure that is comparable with that of asymptomatic patients having no distal polyps, either hyperplastic or adenomatous. When only small distal adenomas are found at screening sigmoidoscopy in asymptomatic persons the decision to do a total colonoscopy should be based on individual considerations, as in such cases only small polyps are to be expected in the proximal colon.

Adenomatous Polyps↗
PubMed1996

[Photodynamic therapy of dysplasia and early cancer of the esophagus].

Photodynamic therapy (PDT) is a new local, endoscopically controlled therapeutic concept based on the selective sensitization of malignant and precancerous lesions prior to light-induced tissue destruction. The first therapeutic experiences with the conventional photosensitizer dihematopor-phyrineter in the treatment of Barrett's esophagus without or with severe dysplasia and mucosal carcinomas of the esophagus demonstrate the efficacy and the curative potential of photodynamic therapy. The unwanted skin photosensitivity and only relative selectivity of the haematoporphyrins however, are somehow unsatisfactory and therefore, an optimization of the method of PDT is necessary. The endogenous photosensitizer aminolaevulinic acid with its high mucosa specificity without phototoxic side effects of the skin which can be administered orally was successfully used by our group for the treatment of patients with severe dysplasia of Barrett's esophagus and superficial squamous cell carcinomas. In patients with severe dysplasia/carcinoma in situ of Barrett's esophagus and early squamous cell carcinomas who pose high surgical risk, photodynamic therapy might be an effective alternative treatment modality in the future.

Animals↗
PubMed1996

[Abscess development caused by ingrown nitinol spiral as a fatal complication of a partially deteriorated MEMOSOND-PEG].

Percutaneous endoscopic gastrostomy (PEG) is a safe method with a low complication rate for providing enteral nutrition. While the "pull" method is the standard technique for PEG placement, alternatively "push" methods were developed in order to minimize peristomal wound infections caused by micro-organisms from the oropharyngeal cavity. Intragastral fixation of the "push" type PEG tube has always been a problem. The MEMOSOND-PEG uses a heat activated nitinol memory spiral as an anchor-like intragastral fixation. So far, an intraabdominal dislocation and a perforation have been reported as severe complications of this type of PEG tube. Five years after insertion we observed the development of an abscess induced by ingrowth of a nitinol spiral into the stomach wall as a further fatal complication in a patient with a MEMOSOND-PEG. The memory metal spiral had pierced the stomach wall after partial destruction of the polyurethane covering. The nitinol spiral was endoscopically extracted in several fragments. Ten days after extraction however, the patient died of combined kidney and liver failure due to a sepsis with Staphylococcus.

Abdominal Abscess↗
PubMed1996

K-ras point mutations are rare events in premalignant forms of Barrett's oesophagus.

OBJECTIVE: In Barrett's adenocarcinomas, in contrast to squamous oesophageal carcinomas, K-ras point mutations are thought to be a frequent event. The frequency of K-ras point mutations in premalignant forms of Barrett's oesophagus (metaplasia, dysplasia) leading to adenocarcinoma with increased risk is currently not known. To establish the frequency of K-ras mutations in premalignant forms of Barrett's oesophagus, we investigated oesophageal biopsy specimens with Barrett's metaplastic and dysplastic epithelium for point mutations in the K-ras gene/codons 12, 13. DESIGN: A total of 412 biopsies from patients with Barrett's oesophagus were histologically classified into biopsies with metaplasia (n = 252), dysplasia (n = 105) and adenocarcinoma (n = 11), as well as biopsies distant from disease (normal, n = 37 and hyperplastic squamous epithelium, n = 7). METHODS: DNA from biopsy specimens was amplified by polymerase chain reaction (PCR) with a modified primer for generating a restriction site in the case of wild type in codon 12. Wild-type or point mutations in the K-ras gene/codons 12, 13 were detected by restriction fragment length analysis of the PCR products. RESULTS: Point mutations in K-ras/codon 12 were found in 9 biopsies (n = 1 in metaplasia, n = 4 in dysplasias, n = 4 in adenocarcinomas). All the other biopsies showed the wild type of K-ras/codon 12. No K-ras/codon 13 mutation (GGCgly-->GACasp) was observed. CONCLUSION: Mutations in K-ras/codon 12 were rarely found in premalignant forms of Barrett's oesophagus. Whereas the screening for K-ras point mutations in metaplastic sites of Barrett's epithelium seems not to be of practical value, the screening for mutations in dysplastic lesions might be helpful to estimate the individual risk for progression of Barrett's epithelium to adenocarcinoma. A further evaluation in larger numbers of patients is needed.

Adenocarcinoma↗
PubMed1995

[The risks of percutaneous endoscopic gastrostomy].

AIM OF STUDY: Percutaneous endoscopic gastrostomy (PEG) having established itself as the standard procedure and preferred method for artificial long-term intestinal nutrition, a retrospective study was undertaken to evaluate the complications and course after PEG. PATIENTS AND METHODS: 1299 patients in whom PEG had been performed between 1.8. 1984 and 1.8. 1993 were sent a standardised questionnaire, 1182 of which could be evaluated (954 males, 228 females; mean age 56.7 [3-94] years). RESULTS: Total duration of PEG was 279830 days, with a mean of 216.2 days per patient. Mortality rate due to the procedure was 0.5%. Severe complications (peritonitis, perforation or faulty puncture) occurred in 9 patients (0.9%). The most common relatively minor complications were peristomal wound infection (8.7%) and brief periods of abdominal pain (4.8%). Typical side effects specific to nutrition were gastrointestinal symptoms, like constipation, diarrhoea, meteorism, vomiting and other signs of illness (39.3%). CONCLUSION: Long-term intestinal nutrition via PEG is a safe, efficacious and cost-effective form of treatment which decreases demands on hospital care and reduces costs.

Adolescent↗
PubMed1995

[Self-expanding metal endoprosthesis in palliation of stenosing tumors of the upper gastrointestinal tract. Comparison of experience with three stent types in 82 implantations].

INTRODUCTION AND AIM OF STUDY: As there are no reports of studies comparing different self-expanding metal stent types the results obtained with three stent types in 73 patients (58 men, 15 women; mean age 65 [43-90] years who had a total of 82 implantation were analysed. PATIENTS AND METHODS: 31 Wallstents were implanted in 23 patients, 31 Ultraflex stents (all without covering) in 30 patients, and 20 Gianturco-Z stents (with covering) in 20 patients. The three groups of patients did not differ significantly with respect to degree of dysphagia, frequency of previous treatment, length of stenosis by tumour, tumour localization and histological tumour type. Six patients, treated with the Gianturco-Z stent, had an tracheo-oesophageal fistula. RESULTS: All 82 implantations were technically successful. Complete occlusion was achieved in all patients with fistulas, as proven radiologically. Serious early complications, namely stent migration, occurred in two patients (2.4%). The degree of dysphagia improved equally in all three groups (Wallstent, from 2.0 to 0.7; Ultraflex from 2.2 to 0.9, Gianturco-Z from 2.1 to 0.5 (not significant). The median follow-up time differed: 89 days for the Wallstent group, 129 for the Ultraflex group and 77 days for the Gianturco-Z group. Tumour ingrowth was the main problem with the non-covered stents. Accordingly, there were 43% reinterventions with the Wallstent, 37% with the Ultraflex and 20% with the Gianturco-Z stents. CONCLUSIONS: Self-expanding metal stents improve palliative treatment of stenosing tumours of the oesophagus and cardia, particularly in view of the low complication rate (< 3%) in the early postimplantation phase. But technical improvements are needed to reduce the number of reinterventions for restenosis in the follow-up period.

Adult↗
PubMed1995

[Restriction enzyme mismatch polymerase chain reaction in the demonstration of Ki-ras-oncogene mutation in carcinoma of the pancreas].

A pilot study was undertaken to test whether combining the polymerase chain reaction with restriction fragment length polymorphism is suitable for the routine diagnosis of carcinoma of the pancreas. The method makes it possible to recognize point mutations in codon 12 of the Ki-ras oncogene. 60 cytological specimens from the pancreatobiliary tract, the bronchopulmonary system (by bronchoalveolar lavage or from pleural effusion) and ascites were tested. Results from nine pancreas carcinoma cell lines served as control. A PCR product was successfully amplified in all cell lines and 47 of the clinical specimens. In all eight samples in which a mutated Ki-ras oncogene was demonstrated, there was at least a suspicion of malignancy by cytological examination. A mutation was also found in four of five pancreas carcinomas. But no mutation was found in one, clinically certain, case of pancreas carcinoma. The described method is an elegant and, most of all, rapid means to complement and optimize any cytological diagnosis.

Ascitic Fluid↗
PubMed1995

[20 years of endoscopic papillotomy. Analysis of 2752 patients at Erlangen Hospital].

Following the development and introduction of endoscopic papillotomy (EPT), 2752 procedures were performed at Erlangen University Hospitals between 1973 and 1993. All papillotomies were evaluated with regard to indications, technique, results, complications and mortality. To show the development process clearly, results for the periods 1973-1980 (A), 1981-1987 (B) and 1988-1993 (C) were summarised separately. The proportion of patients with common bile duct stones was 91% in group A, 60% in group B and 41% in group C. By contrast the number of papillotomies for malignant disease rose from 1% (A) to 26% (B) and 29% (C). More recent indications such as chronic pancreatitis (11%), biliary pancreatitis (5%) and others (for example sphincter of Oddi dysfunction) (11%) were first seen in group C. While the Erlangen standard papillotomy was used in almost all cases in group A (96%), the precut technique was used (mostly with needle knife) in one-third of all papillotomies in groups B and C (32%). The success rate for EPT in all three periods was highest for common bile duct stones (from 96% for group A to 98% for groups B and C). For malignancies, the success rate was lower (89% in groups B and C). The complication rate fell significantly with time (P < 0.05) from 11% (A) to 7.6% (B) and 6.3% (C). Precut techniques did not increase the complication rate. While 71% of all complications were treated surgically in period A, the proportions fell to 28% (B) and then to 7.5% (C). Method-related mortality fell from 1.1% (A) to 0.4% (B) and 0.5% (C).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1995

[Multicenter prospective study of the current status of treatment for bleeding ulcer in Germany].

The current state of ulcer treatment in Germany was analysed in a prospective multi-centre study. It was based on 1139 consecutive patients admitted to the participating hospitals because of upper gastrointestinal bleeding. The source of the bleeding was identified by diagnostic endoscopy in 1075 patients (94%), from a gastric and/or duodenal ulcer in 546 of them (mean age 62 +/- 18 years). Using Forrest's classification, 4% of patients were in bleeding stage Ia, 17% in stage Ib, 16% stage IIa, 30% stage IIb and 33% stage III. An attempt to arrest bleeding through the endoscope was made in 233 patients (43%): more often with tissue-preserving substances (epinephrine +/- NaCl in 36%, fibrin glue +/- epinephrine in 24%) than with tissue-damaging procedures (epinephrine + polidocanol +/- NaCl in 26%, epinephrine + thermocoagulation in 7%). Primary haemostasis was achieved in 219 patients (94%). There was a total of 66 recurrences of bleeding (12%), but the rate was 18% after endoscopic haemostasis. 64 patients (12%) required operative intervention, including initial emergency operations. Severe complications (infections, organic failure) occurred in 82 patients (16%). 114 of the 546 patients were in the high risk group (older than 60 years; high amount of bleeding). Their bleeding recurrence and mortality rates (27 and 22%, respectively) were significantly higher (P < 0.01) than those of the total group. Overall mortality rate was 11% (58 patients). The mortality rate depended on the severity of initial bleeding (26% for Forrest group Ia). After recurrent bleeding the mortality rate was 34% with conservative and 33% with operative treatment. 7% of all deaths were the direct result of bleeding. The following factors prognostically closely correlated with mortality rate: age of patient (P < 0.01); haemoglobin < 8 g/dl on admission (P < 0.05); initial severity of bleeding (Forrest group I; P < 0.05); and recurrence of bleeding (P < 0.001).

Age Factors↗
PubMed1995

Gianturco-Z stents in the palliative treatment of malignant esophageal obstruction and esophagotracheal fistulas.

BACKGROUND AND STUDY AIMS: The palliative endoscopic treatment of malignant obstruction of the upper gastrointestinal tract, including esophagorespiratory fistulas, is often difficult. The efficacy of polyethylene-coated [corrected] Gianturco-Z stents in these sometimes complicated tumor stenoses was investigated. PATIENTS AND METHODS: Twenty patients with malignant obstruction of the esophagus and the cardia, including six patients with esophagotracheal fistulas, were treated with Gianturco-Z stents. Five patients had previously been provided with another type of self-expanding metal endoprosthesis (two with Wallstents and three with Ultra-flex memory metal stents), and needed retreatment because of tumor ingrowth or overgrowth, esophagotracheal fistulas, or insufficient stent expansion. All data acquired prior to and during stent implantation, as well as during the follow-up period, were recorded prospectively. RESULTS: No technical problems occurred during the implantation of the stents. Nineteen of 20 Gianturco-Z stents (95%) spontaneously showed sufficient expansion at the endoscopic control, which was conducted within the following 48 hours. All patients, with the exception of one, reported immediate improvement of their dysphagia. The sealing of the six fistulas was also achieved. Severe early complications, such as bleeding or perforation, did not occur, but one stent migration was encountered. Two types of minor problems were observed: short-term retrosternal and epigastric pain (11 patients) and formation of a pouch at the upper rim of the stent (one patient). In the follow-up, tumor overgrowth of the stent ends was found in one patient, who was retreated with electrocoagulation. Tumor infiltration of the wire mesh has not been observed so far. In one patient, dislocation of a stent into the stomach occurred (probably as a result of endoscopic measures being performed to control tumor bleeding). CONCLUSIONS: We conclude that the treatment of malignant esophageal obstructions, including esophagorespiratory fistulas, with Gianturco-Z stents is effective, and that implantation is safe, especially in the case of tumor stenoses in the proximal esophagus. The expansile force of the stent is sufficient even for very firm strictures; and the polyethylene [corrected] covering of the stent seems to prevent tumor ingrowth.

Adenocarcinoma↗
PubMed1995

Memory metal stents for palliation of malignant obstruction of the oesophagus and cardia.

Thirty patients with incurable malignant obstruction of the oesophagus and cardia were treated with self expanding oesophageal memory metal stents (Ultraflex) in a prospective study. The endoprostheses were successfully placed in all patients. Within one week after implantation dysphagia had improved in 25 of 30 patients (83%). Stent expansion was incomplete within one week after implantation in 12 of 30 patients (40%). After an average of two dilatation sessions eight of 12 stents had expanded completely. Five patients complained of retrosternal pain and three of them suffered from heartburn over several days despite acid inhibition. Major problems in the follow up period occurred in 10 of 30 patients (30%) and included late perforation (one) and tumour ingrowth/overgrowth (nine). All of these complications were treated endoscopically. Improvement of the dysphagia of the patients with tumour ingrowth/overgrowth lasted for about eight weeks (median; range: 2-38 weeks). Until November 1994 six of 30 patients were still alive with a survival time of 309 days (median; range: 103-368 days). It is concluded that oesophageal memory metal stents are easy to implant, prove effective in the palliation of malignant oesophageal obstructions, and have a low risk of severe complications. The only disadvantages are that incomplete initial stent expansion as well as tumour ingrowth/overgrowth occurred in nearly one third of the patients.

Adenocarcinoma↗