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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
PubMed2001

Development of early gastric cancer 4 and 5 years after complete remission of Helicobacter pylori associated gastric low grade marginal zone B cell lymphoma of MALT type.

AIM: To report 3 of 120 patients on the German MALT lymphoma trial with H. pylori associated gastric MALT lymphoma who developed early gastric cancer 4 and 5 years, after complete lymphoma remission following cure of H. pylori infection. PATIENTS AND RESULTS: Three patients (two men, 74 and 70 years; one women, 77 years) with H. pylori-associated low-grade MALT lymphoma achieved complete lymphoma remission after being cured. Surveillance endoscopies were performed twice a year in accordance to the protocol. Four years after complete lymphoma remission in two patients, and after 5 years in the other, early gastric adenocarcinoma of the mucosa-type, type IIa and type IIc, respectively, was detected, which were completely removed by endoscopic mucosa resection. In one patient, the gastric cancer was diagnosed at the same location as the previous MALT lymphoma, in the other patients it was detected at different sites of the stomach distant from location of the previous MALT lymphoma. The patients were H. pylori negative during the whole follow-up time. CONCLUSION: These findings strengthen the importance of regular Long-term follow-up endoscopies in patients with complete remission of gastric MALT lymphoma after cure of H. pylori infection. Furthermore, gastric adenocarcinoma may develop despite eradication of H. pylori.

Adenocarcinoma↗
PubMed2000

Quantum correlations in the nonperturbative regime of semiconductor microcavities.

The nonlinear optical response of semiconductor microcavities in the nonpertubative regime is studied in resonant single-beam-transmission and pump-probe experiments. In both cases a pronounced third transmission peak lying spectrally between the two normal modes is observed. A fully quantized theory is essential for the agreement with the experimental observations, demonstrating that quantum fluctuations leading to intraband polarizations are responsible for this effect.

Journal Article↗
PubMed2000

Dominance of radiative coupling over disorder in resonance Rayleigh scattering in semiconductor multiple quantum-well structures.

Resonance Rayleigh scattering by periodic semiconductor multiple quantum-well structures is studied experimentally and theoretically. Polaritonic effects are found to dominate disorder in the secondary emission dynamics. The coexistence of several radiant polaritonic modes with different radiative decay times leads to polarization beating between modes, strongly influences the rise times, and determines the fast decay times of the resonance Rayleigh scattered signals.

Journal Article↗
PubMed2000

Photodynamic therapy.

Photodynamic therapy (PDT) is a treatment modality that utilizes a photosensitizing drug activated by laser-generated light and is proving effective for oncologic and nononcologic applications in the gastrointestinal tract. This article provides an overview of the most frequently used photosensitizers and clinical PDT studies in the upper gastrointestinal tract. In the future, the best indications for PDT in the esophagus will not comprise the palliative treatment of obstructing tumors but precancerous lesions such as Barrett's esophagus with or without dysplasia and early cancer. PDT might establish itself as a minimally invasive treatment alternative compared with surgery for high-grade dysplasia or early mucosal cancer of the esophagus.

Esophageal Neoplasms↗
PubMed2000

Rectal stricture associated with the long-term use of ibuprofen suppositories.

Here, we report the case of a 64-year-old woman who suffered from chronic lower backache for which she received ibuprofen suppositories. The patient was admitted to the hospital with a suspected rectal tumor. Clinical examination did not reveal any abnormal finding apart from a mild, bilateral peritibial edema. On rectal examination, an area of stenosis was detected approximately 7 cm above the anal verge. All laboratory parameters, including different tumor markers, were within normal range. Pelvic CT scan and colonoscopy revealed a circular rectal stenosis with severe destruction of the rectal mucosa. The rectal biopsy taken during endoscopy showed severe acute and chronic ulceration, chronic granulation and fibrosis with lymphocytic infiltration. After exclusion of sexually transmitted diseases such as syphilis and lymphogranuloma venerium or exposure to drugs as a possible cause of rectal stenosis, the history in this particular case suggests that the prolonged use of the cyclooxygenase (COX) inhibitor "ibuprofen" as a suppository is the cause of mucosal destruction and rectal stenosis.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

Endoscopic mucosal resection of early cancer and high-grade dysplasia in Barrett's esophagus.

BACKGROUND & AIMS: In view of the mortality and morbidity rates of esophagectomy and the relatively large group of inoperable patients, local therapeutic techniques are required for high-grade dysplasia and early Barrett's cancer. METHODS: A prospective investigation of endoscopic mucosal resection was conducted in 64 patients (mean age, 65 +/- 10 years) who had early carcinoma (61 patients) or high-grade dysplasia (3 patients) in Barrett's esophagus. Thirty-five patients met the criteria for low risk: macroscopic types I, IIa, IIb, and IIc; lesion diameter up to 20 mm; mucosal lesion; and histological grades G1 and G2 and/or high-grade dysplasia (group A). The remaining 29 patients were included in group B (high risk). RESULTS: A total of 120 resections were performed, with no technical problems encountered. The mean number of treatment sessions per patient was 1. 3 +/- 0.6 in group A and 2.8 +/- 2.0 in group B (P < 0.0005). Only one major complication occurred, a case of spurting bleeding, which was managed endoscopically. Complete local remission was achieved significantly earlier (P = 0.008) in group A than in group B. In May 1999, complete remission had been achieved in 97% of the patients in group A and in 59% of those in group B; however, 1 patient in group A and 9 in group B are still undergoing treatment or awaiting the first check-up. During a mean follow-up of 12 +/- 8 months, recurrent or metachronous carcinomas were found in 14%. CONCLUSIONS: Endoscopic mucosal resection of early carcinoma in Barrett's esophagus is associated with promisingly low morbidity and mortality rates. The procedure may offer a new minimally invasive therapeutic alternative to esophagectomy, especially in low-risk situations. Comparisons with surgical results will need to be done when the long-term results of this procedure become available.

Adult↗
PubMed2000

Analysis of the risk factors associated with endoscopic sphincterotomy techniques: preliminary results of a prospective study, with emphasis on the reduced risk of acute pancreatitis with low-dose anticoagulation treatment.

BACKGROUND AND STUDY AIMS: The aim of the present study was to analyze the risk factors associated with complications of endoscopic sphincterotomy (ES). PATIENTS AND METHODS: In all consecutive endoscopic sphincterotomies carried out between September 1994 and December 1996, the possible risk factors (12 patient-related factors and 12 procedure-related ones), as well as the concomitant medical treatment, indications, techniques, and success of endoscopic sphincterotomy were evaluated prospectively. Risk factors were analyzed on an exploratory basis using univariate methods. "Potential risk factors" (univariate, P<0.1) underwent multivariate analysis to determine independent "risk factors" (multivariate, P<0.05). In addition, the complication rate was calculated according to the number of potential risk factors present. RESULTS: A total of 438 patients who underwent ES were analyzed. Complications occurred in 7.5% (n = 33; acute pancreatitis 4.3%, hemorrhage 2.3 %, cholangitis 0.9%, technical 0.2%). Statistical analysis of the complications identified three independent risk factors (coagulopathy, patient age (< or =60 years, pancreas divisum), and one protective factor (pancreatic duct obstruction). The frequency of acute pancreatitis was increased by two independent risk factors (pancreas divisum, ES frequency <40 procedures/year) and was reduced if low-dose anticoagulation (unfractionated heparin or low molecular weight heparin) was administered (0.9%, one of 115 vs. 5.8%, 18 of 313; P<0.05). The effect of anticoagulation was not confounded by the presence or absence of other potential risk factors for acute pancreatitis. Neither the risk nor the severity of hemorrhage were increased by low-dose anticoagulation. Due to the low number of events, only potential risk factors for hemorrhage were identified (coagulopathy, intensive-care treatment). The overall complication rate and the incidence of pancreatitis and hemorrhage increased significantly depending on the number of simultaneous potential risk factors present (P<0.0001). CONCLUSIONS: Patients at risk for complications after endoscopic sphincterotomy can be identified by risk factor analysis. These data suggest the hypothesis that low-dose anticoagulation prior to endoscopic sphincterotomy reduces the risk of acute pancreatitis after sphincterotomy.

Acute Disease↗
PubMed2000

The Erlangen Endo-Trainer: life-like simulation for diagnostic and interventional endoscopic retrograde cholangiography.

The Erlanger Endo-Trainer offers a large spectrum of training possibilities in endoscopic techniques using life-like biological specimens. We organised the first pilot study of interventions at the papilla and the bile duct under x-ray control. Specially prepared upper visceral porcine organ packages including the esophagus, stomach, duodenum, liver, gallbladder and bile ducts were implanted into the Endo-Trainer. Furthermore, small stones were introduced into the bile duct. The test study was carried out by a senior endoscopist assisted by his endoscopy nurse. The following steps could therefore be carried out as a structured team-training scheme: Introduction of the side-viewing endoscope and passage into the duodenum; identification and adjustment at the papilla; cannulation of the papilla; selective bile duct imaging with contrast application under x-ray vision; placement of a guidewire; papillotomy; stone extraction and finally placement of a plastic stent. The special value of this type of simulation is the fact that endoscopic techniques can be trained in the usual manner with real tissue-feeling using regular commercial instruments. Although there is general consent that individual practice on the patient cannot be completely replaced by simulator training, a suitable and realistic simulation model can be of great value, for initial steps prior to "real" patient contact as well as for refining techniques and tactics.

Animals↗
PubMed2000

Is endoscopic drainage of common bile duct stenoses in chronic pancreatitis up-to-date?

OBJECTIVE: Common bile duct (CBD) stenoses often complicate chronic pancreatitis (CP). Although endoscopic drainage is employed as a standard procedure in malignant CBD stenoses, it is not yet the approved standard therapy of CBD stenosis in CP. METHODS: The records of 31 patients with CBD stenosis in CP who had undergone endoscopic placement of plastic endoprostheses into the bile duct between January 1991 and February 1997 were analyzed retrospectively. In all, 18 patients suffered from jaundice and 13 patients exclusively showed serological cholestasis. Upstream dilation of the CBD (19 +/- 6.6 mm, 12-35 mm) was detected by ERCP in all patients. In total, 101 endoprostheses were implanted endoscopically, exchanged after 3 +/- 2 months, and removed after 10 +/- 8 months. RESULTS: All jaundiced patients showed immediate improvement of cholestasis after drainage. At the time of last exchange or after stent removal, prestenotic CBD dilation was reduced in 55% of all patients. Complete regression of stenosis and prestenotic dilation was accomplished only in 13%; dilation remained unchanged in 10%, and even showed progression in 22%. A total of 29 patients were followed-up over 24 months. Cholestatic parameters remained normal in all patients with complete normalization of the CBD, and were only moderately increased in another 10 patients, 7 and 28 months after stent removal, respectively. CONCLUSIONS: Technical and immediate clinical success of CBD stenting in patients with CBD stenoses due to CP is high; however, long-term complete normalization of the bile duct is rare. Endoscopic drainage of CBD-stenosis in patients with CP can be recommended to alleviate acute cholestasis, but not yet as a definite treatment.

Acute Disease↗
PubMed2000

Photodynamic therapy of gastric cancer.

Photodynamic therapy is a fascinating concept that will continue to occupy many research groups around the world in coming years. Although a widespread clinical application for the method has not yet emerged, there are good prospects that photodynamic therapy will establish itself at major gastroenterologic centers as an endoscopic procedure with few or no side effects in the treatment of Barrett's esophagus (sever dysplasia and early carcinoma) and, in selected cases, for the treatment of early gastric carcinoma.

Drug Administration Routes↗
PubMed1999

Photodynamic destruction of high grade dysplasia and early carcinoma of the esophagus after the oral administration of 5-aminolevulinic acid.

BACKGROUND: 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. 5-aminolevulinic acid (5-ALA) appears to be a promising alternative photosensitizer with a high mucosa specificity without phototoxic side effects on the skin. The authors report on their experiences with this new form of PDT in 27 patients. METHODS: Twenty-seven patients (6 females and 21 males; ages 47-79 years) with histologically proven high grade dysplasia (n = 9) and early carcinoma (normal endoultrasonography or classified as uT1N0M0; n = 19; 1 patient had 2 lesions) of the esophagus were included in this study. Approximately 4-6 hours after oral ingestion of 5-ALA in a dosage of 60 mg/kg of body weight, laser light irradiation was conducted with a dye laser system with a wavelength of 635 nanometers at a light dose of 150 J/cm(2). RESULTS: The length of the segment of the esophagus with severe dysplasia or carcinoma of the mucosa varied between 0.5-9.0 cm (mean length, 2.5 cm). High grade dysplasia was eradicated in all patients. In addition, 19 mucosal tumors in 18 patients were treated successfully in 10 of 19 cases with an average of 1.7 treatment sessions and a mean follow-up of 16.9 months (range, 3-37 months). Method-related morbidity and mortality were not observed. CONCLUSIONS: Severe dysplasia and superficial (</=2 mm) mucosal carcinoma of the esophagus can be ablated completely by 5-ALA-PDT. PDT with 5-ALA has few side effects and might offer an alternative to esophagectomy or radiochemotherapy.

Aged↗
PubMed1999

Extraction of migrated self-expanding esophageal metal stents.

BACKGROUND: When self-expanding metal stents are used in the palliative treatment of malignant stenoses complications can occur and require the endoscopic extraction of the stent. METHODS: Three Gianturco-Z stents and two EsophaCoil stents had to be extracted because of migration (4 patients) and strangulation of healthy esophageal tissue between the coil loops during EsophaCoil stent release (1 patient). Because of the strong expansion force of the Gianturco-Z stent, the plastic sheath of a polypectomy snare was replaced by the steel sheath of a basket used for mechanical lithotripsy of bile duct stones. The sufficient resistance of the steel sheath allowed the stents to be compressed. The EsophaCoil stents were gradually retracted with a polypectomy snare over a plastic tube. RESULTS: All stents could be extracted successfully. There were no severe complications related to extraction. CONCLUSION: By means of the endoscopic extraction techniques described above, it is possible to safely remove self-expanding esophageal stents.

Aged↗
PubMed1999

KTP laser destruction of dysplasia and early cancer in columnar-lined Barrett's esophagus.

BACKGROUND: The rising incidence of esophageal adenocarcinoma in western countries requires a new strategy in the management of dysplasia in Barrett's esophagus. Esophagectomy, which has high morbidity and mortality rates, has been recommended to treat patients with severe dysplasia. Strictly superficial laser coagulation with tissue ablation therefore is a desirable option for the management of dysplasia in Barrett's esophagus because the tissue to be ablated is only about 2 mm thick. Potassium-titanyl-phosphate (KTP) laser light with a wavelength of 532 nm is preferentially absorbed by hemoglobin and therefore combines excellent coagulation with limited tissue penetration. We report first clinical results with KTP laser superficial vaporization of dysplasia and early cancer in Barrett's esophagus. METHODS: Eight men and 2 women 43 to 84 years of age with short segments of Barrett's esophagus or traditional Barrett's esophagus and histologically proved low-grade (n = 4) and high-grade (n = 4) dysplasia or early adenocarcinoma (n = 2) were selected for this pilot study. For all patients thermal endoscopic destruction was conducted with a frequency-doubled neodymium:yttrium-aluminum-garnet (Nd:YAG) KTP laser system. Laser therapy was performed by means of the free-beam method with coaxial insufflation of gas. An average of 2.4 sessions per patient were required for ablation of the Barrett's mucosa. RESULTS: Two to three days after laser treatment the response of the ablated mucosa was assessed with endoscopy and biopsy. Samples taken showed fibrinoid necrosis of the mucosal layer. A complete response was obtained for all 10 patients. Replacement by normal squamous cell epithelium was induced in combination with acid suppression therapy of up to 80 mg omeprazole daily. No complications occurred. In two patients biopsy showed specialized mucosa beneath the restored squamous cell epithelial layer. Follow-up times were as long as 15 months (mean value 10.6 months). CONCLUSIONS: KTP laser destruction of Barrett's esophagus induced mucosal regeneration with normal squamous cell epithelium in combination with acid suppression. Limitation of the depth of thermal destruction in Barrett's esophagus minimizes risk for perforation or stricture formation. KTP laser ablation of Barrett's esophagus seems to be feasible and safe in short segments of Barrett's esophagus with dysplasia or early cancer.

Adenocarcinoma↗
PubMed1999

Impact of skill and experience of the endoscopist on the outcome of endoscopic sphincterotomy techniques.

BACKGROUND: Our aim was to assess the influence of the skill and experience of the endoscopist on the success and risk of endoscopic sphincterotomy techniques. METHODS: The outcome of all endoscopic sphincterotomies (n = 1335) carried out between 1988 and 1995 were retrospectively analyzed with respect to the endoscopist performing the procedure. Endoscopists were differentiated according to whether they had previous experience with endoscopic sphincterotomy techniques (n > 100) and the frequency of endoscopic sphincterotomy during the study period (>40, 26 to 40, 10 to 25, <10 per year). RESULTS: Indications for endoscopic sphincterotomy techniques and technical execution had only a minor influence on the results of endoscopic sphincterotomy and were comparable for the individual endoscopists. The overall success rate of endoscopic sphincterotomy was 94.4% and did not significantly differ among the endoscopists. The overall complication rate of endoscopic sphincterotomy was 7.3%. Endoscopists learning endoscopic sphincterotomy techniques with a case frequency of less than 10 procedures per year had a consistently high complication rate (10.5%). Those learning endoscopic sphincterotomy techniques with a case frequency of more than 25 procedures per year had an above-average complication rate for their first 40 endoscopic sphincterotomy procedures and a significant decrease in complication rate as the number of procedures increased. The complication rate for experienced endoscopists was 7.7%. There were distinct and, in one case, significant differences in complication rates between individual endoscopists (11.5% vs. 4.8%, p = 0.01). However, when corrected for multiple testing, there were no significant differences at the p < 0. 05 level. The endoscopic sphincterotomy frequency of the endoscopist was the only significant risk factor for complications. Endoscopists with a frequency of more than 40 procedures per year had a significantly lower complication rate (5.6%) than endoscopists with a lower case frequency (9.3%, p < 0.05). CONCLUSIONS: A low endoscopic sphincterotomy frequency is, even for endoscopists with previous experience with the procedure, a risk factor for complications after endoscopic sphincterotomy. The learning of endoscopic sphincterotomy techniques requires a minimum of 40 procedures, but also after 100 procedures a further decrease of the complication rate can be expected.

Adult↗
PubMed1999

Antibiotic prophylaxis in percutaneous endoscopic gastrostomy (PEG): a prospective randomized clinical trial.

BACKGROUND AND STUDY AIMS: The most frequent complication reported for percutaneous endoscopic gastrostomy (PEG) is peristomal wound infection which occurs in as many as 30 % of patients. In the studies published so far, the question of whether antibiotic prophylaxis reduces the incidence of peristomal wound infection has remained controversial. We therefore conducted a prospective, randomized trial to determine whether antibiotic prophylaxis can reduce the incidence of peristomal wound infection associated with PEG. PATIENTS AND METHODS: During a 2-year-period a total of 347 patients (251 men, 96 women; mean age 60.2+/-5) were included in our study. In all cases, a 9-French gauge Freka gastrostomy tube was inserted using the "pull" technique. The patients were randomly assigned to three different treatment groups (group 1, antibiotic prophylaxis with 2 g cefotaxime; group 2, antibiotic prophylaxis with 4g piperacillin plus 0.5g tazobactam; group 3, no antibiotic prophylaxis). For a period of one week after gastrostomy, the peristomal area was evaluated using a wound score. According to the score, peristomal infections were classified as being of degree I-IV. Infections of up to degree III were regarded as minor, while an infection of degree IV was defined as a severe complication. RESULTS: PEG tubes were successfully placed in 336/347 patients (97 %). Of the 336 patients, 29 were excluded because of incomplete follow up (dropout rate 9%). Cases included were: in group 1, n = 101; in group 2, n = 100, and in group 3, n = 106. There was no mortality related to PEG insertion. There were five instances of severe complications (1.6%). Patients who received antibiotic prophylaxis had mean daily combined wound scores that were significantly lower than those of patients without antibiotic prophylaxis (P < 0.01). The control group (no antibiotic prophylaxis) exhibited significantly more peristomal wound infections of degree III (n = 8) than antibiotic prophylaxis group 1 (n = 0, P < 0.001) or antibiotic prophylaxis group 2 (n = 1, P < 0.012). Three patients in group 3 (no antibiotic prophylaxis) and one patient in group 2 developed peritonitis. CONCLUSIONS: Severe wound infections requiring medical or endoscopic intervention are very rare events after PEG insertion. Antibiotic prophylaxis significantly reduces the risk of peristomal wound infection associated with PEG insertion. Antibiotic prophylaxis, therefore, is to be recommended as a general measure in percutaneous endoscopic gastrostomy.

Antibiotic Prophylaxis↗
PubMed1999

A new long-range through-the-scope balloon applicator for photodynamic therapy in the esophagus and cardia.

BACKGROUND AND STUDY AIMS: Photodynamic therapy (PDT) is a new local, endoscopically controlled therapeutic technique based on the sensitization of malignant and precancerous lesions prior to light-induced tissue destruction. PDT of Barrett's esophagus with severe dysplasia, or of mucosal carcinomas and superficial squamous-cell cancer of the esophagus, requires light application devices allowing homogeneous illumination of the tissue surface in spite of esophageal motility and respiratory movement. On the basis of a commercially available through-the-scope balloon system, we developed a long-range light applicator for homogeneous and circumferential irradiation during PDT, and describe here the initial clinical experience with the device. PATIENTS AND METHODS: The new balloon applicator consists of a flexible cylindrical diffuser fiber with a length of up to 10 cm, depending on the lesion to be illuminated, and an inflatable balloon based on the type of balloon used for esophageal dilation. The balloon is made of a transparent polyurethane membrane with negligible absorption (<5%) at lambda = 600-700 nm, and it can be positioned through the biopsy channel of a conventional endoscope, with direct endoscopic visualization of the targeted lesion. The light intensity distribution perpendicular to the optical axes of the diffuser was measured for red laser light (lambda = 632.8 nm) and for green laser light (lambda = 542 nm). The study of photodynamic treatment included two women and four men (aged 48-79 years) with histologically proved high-grade dysplasia (n = 2) or mucosal cancer in Barrett's esophagus (n = 2) and superficial squamous-cell cancer (SCC) (n = 2), who had undergone EUS staging showing uT0 or uT1N0. Laser light irradiation was conducted after oral ingestion of 5-aminolevulinic acid (5-ALA) or intravenous administration of meta-(tetrahydroxyphenyl)chlorin (mTHPC). RESULTS: Both in vitro and in vivo, precise positioning of the new application system at the targeted tissue and homogeneous illumination were feasible, safe and effective. The total efficiency of transmitted light at wavelengths of lambda = 632.8 nm and lambda = 542 nm was 85-90%. A high degree of homogeneity was measured with applicator lengths of between 15 mm and 95 mm, and the maximum deviation from the mean intensity extended over a range of 40% over the total length of 80 mm. High-grade dysplasia was eradicated in all patients, and in addition mucosal cancer was successfully destroyed in three-quarters of them, requiring an average of 1.3 treatment sessions, with a mean follow-up of 12 months (range 10-15 months). CONCLUSIONS: This centering balloon system may in the future be capable of improving light application techniques during esophageal photodynamic therapy, making PDT a more reliable alternative modality for minimally invasive treatment of high-grade dysplasia and early Barrett's esophagus or squamous-cell carcinoma, as compared with esophagectomy.

Adenocarcinoma↗