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Biomedical subjects

S Seewald

Publications and source records attributed to S Seewald.

At least 19 recordsLinked to original sources
PubMed2006

Endoscopic mucosal resection of early esophageal squamous cell cancer using the Duette mucosectomy kit.

BACKGROUND AND STUDY AIM: Endoscopic mucosal resection (EMR) is a less invasive alternative treatment strategy to surgery for intramucosal esophageal squamous cell carcinoma (SCC). This study described our initial experience with the newly introduced Duette Multiband Mucosectomy Kit (Cook Ireland Ltd, Limerick, Ireland) for the treatment of extensive early esophageal SCC. PATIENTS AND METHODS: Five patients with extensive early esophageal SCC, covering at least half of the circumference of the esophageal wall and measuring a mean of 2.8 cm longitudinally, underwent EMR after EUS staging. RESULTS: EMR was successfully completed in one session in five patients. Post-EMR stricture occurred in four patients but was successfully treated with bougienage. One patient did not return for follow-up after bougienage and died from ischemic heart disease 3 months later. For the remaining four patients, there was no recurrence over a mean follow up of 14.7 months. CONCLUSION: This new device obviates the need for repeated insertion of the endoscope during the process of ligation and resection and thus facilitates EMR of extensive SCC.

Aged↗
PubMed2006

Primary precutting versus conventional over-the-wire sphincterotomy for bile duct access: a prospective randomized study.

BACKGROUND AND STUDY AIMS: Precut is a well-known technique that is used if repeated attempts at common bile duct (CBD) cannulation fail. Opinions on the complication rate of precut are conflicting, however. The aim of the present study was to compare the efficacy and complication rate of precut used as a primary method of CBD access with the efficacy and safety of the conventional technique. PATIENTS AND METHODS: During the 19-month study period, consecutive patients who were scheduled for first-time endoscopic sphincterotomy (ES) for a variety of biliary disorders were randomized into two groups: patients in group A underwent conventional wire-guided biliary cannulation followed by ES (with precut being performed only when this failed); in patients in group B precut was used as a primary technique to gain biliary access, followed by wire-guided ES. We used a specially designed, modified Erlangen type of sphincterotome for precutting. RESULTS: A total of 291 patients (100 men, 191 women; mean +/- SD age 65 +/- 17.5 years) were recruited: 146 patients were assigned to group A (conventional approach) and 145 to group B (primary precut approach). The indications for ES were comparable in the two groups. In group A, wire-guided cannulation of the CBD failed in 42 patients. Secondary precut was successful in 41 of these patients, leading to an overall success rate of 99.3 %. In group B, the ES success rate using primary precut was 100 % at the first attempt. The mean time to successful deep CBD cannulation was 8.3 +/- 2.1 minutes in group A and 6.9 +/- 1.8 minutes in group B ( P < 0.001). The incidence of mild to moderate pancreatitis was similar in the two groups (2.9 % in group A vs. 2.1 % in group B, P > 0.05). Mild bleeding occurred in only one patient (from group A) and this was controlled by epinephrine injection. None of the study patients developed severe pancreatitis or perforation. CONCLUSIONS: In experienced hands, an approach using primary precut appears to be at least as successful and safe as a conventional approach using guide-wire-based CBD cannulation followed by ES, and might also be a quicker method.

Adolescent↗
PubMed2004

Is endoscopic polypectomy an adequate therapy for malignant colorectal adenomas? Presentation of 114 patients and review of the literature.

PURPOSE: This study was designed to evaluate the outcome of endoscopic polypectomy of malignant polyps with and without subsequent surgery based on histologic criteria. METHODS: Consecutive patients with invasive carcinoma in colorectal polyps endoscopically removed between 1985 and 1996 were retrospectively studied. Patients with complete resection, grading G1 or G2, and absence of vascular invasion were classified as "low risk." The other patients were classified "high risk." Available literature was reviewed by applying similar classification criteria. RESULTS: A total of 114 patients (59 males; median age, 70 (range, 20-92) years) were included. Median polyp size was 2.5 (0.4-10) cm. After polypectomy, of 54 patients with low-risk malignant polyps, 13 died of unrelated causes after a median of 76 months, 5 had no residual tumor at surgery, and 33 were alive and well during a median follow-up of 69 (range, 9-169) months. Of 60 patients with high-risk malignant polyps, 52 had surgery (residual carcinoma 27 percent). Five of eight patients not operated had an uneventful follow-up of median 57 (range, 47-129) months. Patients in the high-risk group were significantly more likely to have an adverse outcome than those in the low-risk group (P < 0.0001). Review of 20 studies including 1,220 patients with malignant polyps revealed no patient with low-risk criteria with an adverse outcome. CONCLUSIONS: For patients with low-risk malignant polyps, endoscopic polypectomy alone seems to be adequate. In high-risk patients, the risk of adverse outcome should be weighed against the risk of surgery.

Adenoma↗
PubMed2003

Variceal bleeding and portal hypertension: has there been any progress in the last 12 months?

A review of the literature on the management of esophagogastric varices published in the last 12 months shows that the data are still quite conflicting. In the primary and secondary prophylaxis of variceal bleeding, beta-blockers are still the mainstay of pharmacotherapy. Measurement of the hepatic portal venous pressure gradient is considered to be a reliable parameter for successful reduction of portal pressure using medical therapy. However, intolerance of propranolol requiring discontinuation of therapy has been observed in approximately 30 % of patients. Patients' compliance with medication may represent another drawback of medical therapy. The role of endoscopic band ligation in secondary prophylaxis is now indisputable, especially in comparison with sclerotherapy. In the primary prevention of variceal bleeding, band ligation is beginning to have a competitive edge over pharmacological therapy. Acute variceal bleeding is no longer a frequent morbid emergency. Most cases of bleeding can now be managed successfully with band ligation and N-butyl-2-cyanoacrylate obliteration. N-butyl-2-cyanoacrylate has come into increasingly widespread use in the treatment of bleeding gastric fundal varices in which surgery or transjugular intrahepatic portosystemic shunting were previously regarded as the preferred therapies.

Acute Disease↗
PubMed2003

Long-term results of endoscopic removal of large colorectal adenomas.

BACKGROUND AND STUDY AIMS: Endoscopic removal of large colorectal polyps has not been widely accepted. The aims of this study were to evaluate our longterm experiences justifying endoscopic resection technique as the treatment of choice. PATIENTS AND METHODS: During a period of 12 years, 288 patients with a total of 302 polyps larger than 3 cm in diameter were treated endoscopically. 224 polyps were sessile and 78 pedunculated. Sessile polyps were removed using the piecemeal technique. Surgery was recommended in patients with unfavorable histology. Patients with favorable histology were followed up at 3 - 6 month intervals in the first year and then every 1 - 2 years. RESULTS: A total of 184 patients with sessile polyps were followed up for at least 6 months. Recurrence rate of 166 benign polyps was 17 % (29/166). Only two patients had malignant recurrence. 8 of 18 patients with malignant polyps underwent surgery while 10 were unfit for surgery. 8 of these patients remained free of recurrence. CONCLUSIONS: Previous concerns about endoscopic removal of large colorectal polyps are no longer justified. The results of this study showed that endoscopic resection of large colorectal polyps is safe and effective. In patients with high operative risk, endoscopic removal may be adequate.

Adenoma↗
PubMed2002

Impact of endoscopic ultrasound for evaluation of submucosal lesions in gastrointestinal tract.

BACKGROUND: Endoscopic ultrasound is widely used following endoscopy for evaluation of suspected submucosal lesions and may guide further management of patients. PATIENTS AND METHOD: A total of 181 consecutive patients with suspected submucosal lesion in the upper gastrointestinal tract were diagnosed by endoscopic ultrasound between 1990-97. We evaluated: 1) the potential of endoscopic ultrasound criteria to predict histological type of submucosal lesions in 69 patients with available histology, 2) the ability of endoscopic ultrasound alone or with clinical presentation, to predict malignancy in 86 patients with available histology or follow-up of >12 months. RESULTS: Sensitivity and specificity for diagnosing 44 gastrointestinal stromal tumours were 95 and 72%, respectively, while 25 miscellaneous lesions were diagnosed correctly in only 56% by endoscopic ultrasound. Diagnosis of malignancy, using any two of three endoscopic ultrasound criteria (heterogeneous echotexture, size >3 cm, irregular margins) showed a sensitivity of 80% and specificity of 77%, giving accurate endoscopic ultrasound diagnosis in 16/20 malignant and 51/66 benign submucosal lesion. Heterogeneous echotexture, size >3 cm, and irregular margins showed a relative risk of 7.2, 5.4 and 4.6, respectively, for presence of malignancy. The presence of symptoms, potentially suggesting malignancy (dysphagia, gastrointestinal bleeding, pain and weight loss), had a relative risk of 4.2, however this did not increase the accuracy of diagnosing malignancy based on endoscopic ultrasound criteria alone. CONCLUSION: The accuracy of endoultrasound is high in diagnosing gastrointestinal stromal tumours, which show a significant potential of malignancy. Endoscopic ultrasound morphology appears to be helpful in selection of patients for surgical or conservative treatment. The accuracy of endoscopic ultrasound in differential diagnosis of non-gastrointestinal stromal tumour lesions is limited.

Adolescent↗
PubMed2001

Interventional endoscopic treatment of upper gastrointestinal bleeding--when, how, and how often.

Acute upper gastrointestinal (GI) bleeding is still associated with high mortality. Reducing the rebleeding rate is the major challenge in therapeutic endoscopy. The following article describes the indications, techniques and limitations of endoscopic treatment of upper GI bleeding. Endoscopic techniques such as endoscopic sclerotherapy (EIS), endoscopic variceal ligation (EVL), cyanoacrylate obliteration, argon plasma coagulation (APC), and the application of hemoclip are described and compared concerning their efficacy. The pros and cons of "second-look" endoscopy are discussed.

Acute Disease↗
PubMed2001

Variceal bleeding and portal hypertension: still a therapeutic challenge?

In the primary prevention of variceal hemorrhage, beta-blockers continue to be the first-line treatment. Newer nonselective beta-blockers with anti-alpha1-adrenergic activity, such as carvedilol, appear to have a better impact on reducing the hepatic venous pressure gradient than propranolol. The addition of isosorbide mononitrate appears to improve the effectiveness of beta-blockers in primary prophylaxis, but not that of somatostatin in the treatment of acute variceal hemorrhage. The use of vasoactive drugs alone in acute variceal bleeding has not proved to be more effective than endoscopic treatment. The advent of endoscopic variceal ligation (EVL) has strengthened the role of endoscopy in the management of bleeding esophageal varices. EVL has improved the results, particularly in terms of lowering the treatment-related morbidity, compared with endoscopic variceal sclerotherapy (EVS). However, the variceal recurrence rate after initial eradication with EVL is relatively high. In contrast to synchronous combined therapy with EVL plus EVS, metachronous combination of EVL and low-dose EVS may improve the results of EVL alone. For bleeding fundic varices, obliteration using cyanoacrylate is currently the treatment of choice. Endosonography (EUS) is coming into more widespread use in the assessment of variceal eradication and in further attempts to improve the results of endoscopic injection therapy. According to two meta-analysis studies, transjugular intrahepatic portosystemic shunt (TIPS) is not yet capable of replacing endoscopic treatment in the secondary prevention of variceal bleeding.

Adrenergic beta-Antagonists↗
PubMed2000

Green tea compounds inhibit tyrosine phosphorylation of PDGF beta-receptor and transformation of A172 human glioblastoma.

The effect of the green tea compounds 2-(3,4-dihydroxyphenyl)-3, 4-dihydro-2H-1-benzopyran-3,5,7-triol (catechin), epicathechin (EC), epigallocathechin-3 gallate (EGCG), epicathechin-3 gallate (ECG) and catechin-3 gallate (CG) on the tyrosine phosphorylation of PDGF beta-receptor (PDGF-Rbeta) and on the anchorage-independent growth of A172 glioblastoma cells in semisolid agar has been investigated. Treatment of A172 glioblastoma with 50 microM CG, ECG, EGCG and 25 microM Tyrphostin 1296 resulted in an 82+/-17%, 77+/-21%, 75+/-8% and 55+/-11%, respectively (mean+/-S.D., n=3) inhibition of the PDGF-BB-induced tyrosine phosphorylation of PDGF-Rbeta. The PDGF-Rbeta downstream intracellular transduction pathway including tyrosine phosphorylation of phospholipase C-gamma1 (PLC-gamma1) and phosphatidylinositol 3'-kinase (PI 3'-K) was also inhibited. Spheroid formation was completely inhibited by 50 microM ECG, CG, EGCG and by 25 microM Tyrphostin 1296. We conclude that catechins of the green tea possessing the gallate group in their chemical structure act as anticancer agents probably partly via their ability to suppress the tyrosine kinase activity of the PDGF-Rbeta.

Catechin↗
PubMed2000

Cholera toxin treatment of vascular smooth muscle cells decreases smooth muscle alpha-actin content and abolishes the platelet-derived growth factor-BB-stimulated DNA synthesis.

The second messenger cyclic AMP regulates diverse biological processes such as cell morphology and cell growth. We examined the role of the second messenger cyclic AMP on rat aortic vascular smooth muscle cell (VSMC) morphology and the intracellular transduction pathway mediated by platelet-derived growth factor beta-receptor (PDGF-Rbeta). The effect of PDGF-BB on VSMCs growth was assessed by [(3)H]-thymidine incorporation. Tyrosine phosphorylation of PDGF-Rbeta, PLC-gamma1, ERK1 and ERK2, p125(FAK) and paxillin as well as Sm alpha-actin was examined by the chemiluminescence Western blotting method. Actin mRNA level was quantitated by Northern blotting. Visualization of Sm alpha-actin filaments, paxillin and PDGF-Rbeta was performed by immunfluorescence microscopy. Cholera toxin (CTX; 10 nM) treatment lead to a large and sustained increase in the cyclic AMP concentration after 2 h which correlated with change of VSMC morphology including complete disruption of the Sm alpha-actin filament array and loss of focal adhesions. Treatment of VSMCs with CTX did not influence tyrosine phosphorylation of p125(FAK) and paxillin but decreased the content of a Sm alpha-actin protein. Maximal decrease of 70% was observed after 24 h of treatment. CTX also caused a 90% decrease of the actin mRNA level. CTX treatment completely abolished PDGF-BB stimulated DNA-synthesis although PDGF-Rbeta level and subcellular distribution and translocation was not altered. Furthermore CTX attenuated the PDGF-BB-induced tyrosine phosphorylation of the PDGF-Rbeta, PI 3'-K, PLC-gamma1 and ERK1/2 indicating an action of cyclic AMP on PDGF-beta receptor. We conclude that although cyclic AMP attenuates the PDGF-Rbeta mediated intracellular transduction pathway, an intact actin filament may be required for the PDGF-BB-induced DNA synthesis in VSMCs.

Actins↗
PubMed2000

Short-term stimulation of vascular smooth muscle cells with platelet-derived growth factor (PDGF)-BB and angiotensin II induces.

Growth factors such as the platelet-derived growth factor (PDGF)-BB and angiotensin II (Ang II) have been shown to induce vascular smooth muscle cell (VSMC) proliferation after long stimulation periods. Little is known though, about the effects of PDGF-BB and Ang II on VSMC proliferation after short stimulation periods. The purpose of our study was to examine whether a short term (3-60 min) stimulation of VSMC with PDGF-BB or Ang II is sufficient to induce cell proliferation. Incubation of VSMC with Ang II (100 nM) or PDGF-BB (50 ng/ml) caused a significant increase in [3H]thymidine incorporation starting after a 3-min stimulation, while the cell counts required 32 and 8 h of stimulation, respectively. Mitogen-activated protein kinase activation reached a maximum at 5-10 min of PDGF-BB or Ang II stimulation. This study demonstrates that the growth-promoting effects of PDGF-BB and Ang II are strongly dependent on the length of the stimulation period and that while prolonged stimulation periods (>8-32 h) result in VSMC proliferation, short ones (3-60 min) result only in [3H]thymidine incorporation without an increase in cell count, a fact of considerable pathophysiological significance, considering that the time kinetics of growth factors in the VSMC microenvironment have not as yet been clarified.

Angiotensin II↗