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Biomedical subjects

M Classen

Publications and source records attributed to M Classen.

At least 91 records · Page 5Linked to original sources
PubMed1996

Initial experience with a new, partially covered Wallstent for malignant biliary obstruction.

BACKGROUND AND STUDY AIMS: Metal billiary stents have been shown to be superior to plastic stents with regard to patency and the risk of dislocation. However, tumor ingrowth through the mesh continues to be a significant problem. We report here on our preliminary experience with covered metal stents. PATIENTS AND METHODS: Ten patients (mean age 68 years) with malignant biliary obstruction, who were not considered to be surgical candidates, received a partially covered Wallstent. The patients were followed up prospectively for one year, including laboratory tests, abdominal ultrasound, and plain abdominal radiographs during the first three months, and by monthly telephone interview thereafter. RESULTS: Stent insertion was technically successful in all patients, and led to a reduction in bilirubin levels from 8.4 mg/dl to 0.7 mg/dl. The mean survival of the patients was 7.5 months after the diagnosis of malignancy, and six months after stent insertion; only two patients were still alive after 12 months. During the observation period, four patients suffered from stent dysfunction for periods of one to nine months. These dysfunctions included three stent occlusions, which were successfully treated by inserting plastic stents, and one dislocation, which was treated by endoscopic replacement of the stent. There appeared to be a correlation between the narrowest stent diameter immediately after release and stent dysfunction. CONCLUSION: Covering biliary metal stents is a potential solution to prevent tissue ingrowth. However, current prototypes need to be improved in order to achieve this goal.

Aged↗
PubMed1996

Efficacy of low-molecular-weight heparin and unfractionated heparin to prevent adhesion of human prostate and bladder carcinoma and melanoma cells to bovine endothelial monolayers. An in vitro study and review of the literature.

Adherence of human prostate carcinoma (PC 3, DU 145), bladder (647 V, J 82) carcinoma and melanoma (RPMI-8252) cell lines to plastic and bovine endothelial monolayers (BEM) was tested in the presence of 0.5, 1, 5, 10, 20 IU of low-molecular-weight heparin (LMWH), unfractionated heparin (UFH) or saline as a control. Culture medium was supplemented either with 5% fetal calf serum or with human plasma. Floating tumor cells were counted after 2, 4, 24 h of culture in microtiter plates without BEM and after 1.5, 3 and 24 h of culture on BEM. Twenty IU of LMWH increased the numbers of bladder carcinoma cells adhering to BEM as did 20 IU of UFH in cultures of DU 145 prostate carcinoma and RPMI-8252 melanoma cells. LMWH obviously does not prevent human prostate and bladder carcinoma and melanoma cells from adhering to BEM more effectively than UFH. The in vivo effect of UFH and perhaps also LMWH that hinders intravenous tumor cell colonization in blood vessels obviously does not depend on the interaction with endothelial cells alone.

Adult↗
PubMed1996

Local cellular immune response in Helicobacter pylori associated type B gastritis--selective increase of CD4+ but not gamma delta T-cells in the immune response to H. pylori antigens.

During recent years the infectious etiology of the majority of cases of chronic active type B gastritis and peptic ulcers has become increasingly evident. The chronicity of clinical symptoms and histopathological features such as numerous mucosal lymphocytic aggregates have implied a role of the specific cellular immune system. Whereas in Type A chronic active gastritis a pathogenetic role of lymphocytes and their target structures have been amply documented, in chronic active type B gastritis particularly that associated with Helicobacter pylori infection the nature of a specific immune response and its role in the pathogenesis of the epithelial and mucosal lesion has remained obscure. Here we report that CD4+ mucosal lymphocytes appear to selectively accumulate in Helicobacter pylori associated chronically active antral gastritis. Moreover, lamina propria gamma delta T lymphocytes were found to be more frequent in chronic active type B gastritis irrespective of the presence of absence of Helicobacter pylori.

Adult↗
PubMed1996

A minimally invasive palliative approach to advanced pancreatic and papillary cancer causing both biliary and duodenal obstruction.

BACKGROUND: In patients with both duodenal and biliary obstruction in whom endoscopic drainage is not feasible, the standard approach has been gastroenterostomy plus biliodigestive anastomosis. We present our results of percutaneous biliary drainage in combination with gastroenterostomy. PATIENTS AND METHODS: Twenty-one patients, who received permanent percutaneous transhepatic biliary drainage (PTBD) and gastroenterostomy in case of symptomatic gastric outlet obstruction were retrospectively evaluated. RESULTS: PTBD insertion succeeded in all patients; minor complications were encountered in 47.6% of cases. Bilirubin fell from 9.2 mg/dl (SD 7.6) to 4.9 mg/dl (SD 3.6). Gastroenterostomy, either open (n = 10) or laparoscopic (n = 6), had to be performed in 16 patients before, during or after PTBD. Thirty day mortality was 23.8%, not related to the procedure, but due to advanced neoplastic disease. Mean survival and hospital stay were 4.9 months (SD 3.6) and 21.5 days (SD 7.3) respectively. CONCLUSIONS: The combination of PTBD and gastroenterostomy offers a promising alternative to surgery. However efforts to reduce complications as well as the duration of hospital stay are necessary.

Adult↗
PubMed1995

[Hemorrhage caused by duodenal varices].

HISTORY AND CLINICAL FINDINGS: A 53-year-old man had been passing tarry stools and bright red blood per rectum for 6 days. He had a history of pyloroplasty for duodenal ulcers, alcoholic liver cirrhosis, stage B in Child's classification, a Le Veen shunt for ascites, grade I oesophageal varices and several episodes of intestinal bleeding of uncertain cause on repeated endoscopies. Haemoglobin levels was now 4.4 g/dl. Neither oesophago-gastro-duodenoscopy nor colposcopy, radiological examination of the small intestine nor scintigraphy discovered the source of bleeding. Computed tomography revealed varices in the horizontal part of the duodenum, confirmed by arteriography. TREATMENT AND COURSE: At a second endoscopy, this time with a long scope, acute bleedings were seen in the venous convolutions and stopped with 4 ml Polidocanol. Bleeding recurred after 10 days, thought to be due to persisting portal hypertension. A transjugular intrahepatic portosystemic stent shunt (TIPSS) was inserted to lower the pressure. Colour-coded Doppler examination at the time of another bleeding 10 weeks later demonstrated occlusion of the TIPSS. It was re-opened by balloon catheter dilatation, since when there have been no further episodes of bleeding. CONCLUSION: The implantation of a TIPSS is a new causative treatment for recurrent bleeding from ectopic varices due to portal hypertension that cannot be treated by endoscopy.

Angiography↗
PubMed1995

Effect of endogenous opioids on vagally induced release of gastrin, somatostatin and bombesin-like immunoreactivity from the perfused rat stomach.

The aim of the present study was to evaluate the effect of the opiate receptor antagonist naloxone on vagally stimulated secretion of bombesin-like immunoreactivity (BLI), somatostatin and gastrin from the isolated rat stomach, which was perfused via the celiac artery with Krebs-Ringer buffer. Vagal stimulation was performed for 10 min with 1 ms, 10 V and 2, 5, 10 or 20 Hz, respectively. In control experiments BLI release increased significantly above basal secretion during a stimulation frequency of 10 Hz (1367 +/- 357 pg/10 min; P < 0.001) and 20 Hz (996 +/- 202 pg/10 min; P < 0.01), but not at 2 and 5 Hz. In comparison to the controls naloxone (10(-6) M) significantly increased BLI secretion at 5 Hz by 573 +/- 150 pg/10 min (P < 0.05), but attenuated the BLI response to higher stimulation frequencies of 10 and 20 Hz to 284 +/- 143 pg/10 min (P < 0.001) and 490 +/- 114 pg/10 min (P < 0.01), respectively. At 2 Hz naloxone had no effect on BLI release. As shown previously the cholinergic blocker atropine (10(-7) M) induced a significant BLI release during vagal stimulation at 2 Hz (680 +/- 233 pg/10 min; P < 0.01) and 5 Hz (935 +/- 324 pg/10 min; P < 0.05), but was without effect at 10 and 20 Hz compared to the controls. The effects of the combination of naloxone and atropine were similar to naloxone and atropine alone. Naloxone had no effect on vagal or GRP-induced regulation of gastrin and somatostatin release.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Pyrimethamine-sulfadiazine resistant cerebral toxoplasmosis in AIDS].

A 48-year-old man with known HIV infection for 4 years was admitted with a 2-week history of increasing brachio-facial paraesthesiae of the left side of the body and pains in the head and neck. Physical examination also showed discrete slowing of mental activity and oral candidiasis. Toxoplasmosis serology showed a low titre with a borderline IgM titre. Cranial computer tomography showed two confluent contrast medium concentrating foci in the region of the head of the caudate nucleus and the right internal capsule. Because toxoplasmosis encephalitis was suspected, treatment was started with sulfadiazine (1 g four times daily), pyrimethamine (25 mg four times daily), folic acid (15 mg daily) and dexamethasone (8 mg three times daily). After 19 days of treatment there was no clinical improvement, and a check CT scan showed worsening with increased oedema of the cerebellar medulla, compression of the lateral ventricles and a mid-line shift of 5 mm. Since the Sabin-Feldman test titre had increased, and there was no evidence to suggest a lymphoma or a viral or fungal infection, toxoplasmosis resistant to standard therapy was postulated, and treatment was started with clindamycin (600 mg three times daily) and pyrimethamine (25 mg four times daily). The clinical features subsided within 4 days. A further check CT scan 14 days later showed almost complete resolution.

AIDS-Related Opportunistic Infections↗
PubMed1995

Treatment of esophagorespiratory fistulas with silicone-coated self-expanding metal stents.

Nine self-expanding silicone-coated modified Gianturco metal stents were inserted in 8 patients (mean age, 58.2 years) for palliation of malignant esophagorespiratory fistulas caused by esophageal (n = 5) or bronchial (n = 3) carcinoma. One patient with a fistula above a 12-cm-long malignant stenosis received two overlapping stents. The implantation procedure was well tolerated by all patients under intravenous sedation and analgesia. After release, the stents expanded to their full diameter, leading to complete occlusion of the fistulas and bridging of the concomitant stenoses. Two patients with lung cancer received an additional tracheobronchial stent before esophageal stent insertion. Failure to maintain complete contact between the proximal stent margin and the esophageal wall led to insufficient sealing of the fistula of 1 patient and recurrent aspiration, manifested 6 days after stent implantation (overall success, 87.5%). The other patients could swallow semi-solid food until death. Seven patients died of advanced metastatic disease after 21 to 121 days (mean, 54 days) and 1 patient of massive hemoptysis 10 days after stent placement, which could be regarded as a complication (procedure-related mortality rate, 12.5%). These preliminary results suggest that peroral insertion of the modified silicone-coated Gianturco stent is a rapid, reasonably safe, and effective procedure for palliation of malignant esophagorespiratory fistulas.

Adenocarcinoma↗
PubMed1995

Comparative trial of pantoprazole and ranitidine in the treatment of reflux esophagitis. Results of a German multicenter study.

In 249 patients with acute symptomatic reflux esophagitis grade II and III (Savary-Miller classification), we compared the efficacy and safety of pantoprazole, a newly developed proton pump inhibitor given at a once-daily dose of 40 mg, with a standard dose of the H2 receptor antagonist ranitidine (150 mg b.i.d.) in a randomized, double-blind, multicenter study. Complete healing was achieved after 4 and 8 weeks of therapy (protocol-correct) in 69 and 82% (pantoprazole) and 57 and 67% (ranitidine), respectively (p = 0.054 at 4 weeks and p < 0.01 at 8 weeks). The predominant symptoms of gastroesophageal reflux, i.e., heartburn and acid eructation, were more effectively reduced in pantoprazole- than in ranitidine-treated patients. The frequency of adverse events was low and did not differ between the two treatment groups. We conclude that pantoprazole is superior to ranitidine in the acute treatment of reflux esophagitis.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

Interstitial buffer capacity influences Na+/H+ exchange kinetics and oxyntic cell pHi in intact frog gastric mucosa.

We studied the influence of interstitial buffer capacity and CO2-HCO3- on oxyntic cell intracellular pH (pHi) in intact frog gastric mucosa. Oxyntic cells in stripped gastric mucosa of Rana esculenta were loaded with the pH-sensitive dye 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, and pHi was assessed fluorometrically. In the presence of a constant serosal and luminal pH, oxyntic cell pHi was dependent on the serosal but not the luminal concentration of cell-impermeable buffer ions such as N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES), tris(hydroxymethyl)aminomethane, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid, and 3-(N-morpholino)propanesulfonic acid. The stepwise increase in oxyntic cell pHi from 6.74 +/- 0.05 with 1 mM HEPES to 7.23 +/- 0.08 was almost completely inhibited by removal of serosal Na+ and by amiloride and dimethyl amiloride, suggesting that it was largely due to Na+/H+ exchange. Increasing the serosal concentration of a CO2-HCO3- buffer from 1% CO2-4 mM HCO3- to 10% CO2-40 mM HCO3- increased oxyntic cell pHi from 7.03 +/- 0.06 to 7.39 +/- 0.07. This CO2-HCO(3-)-dependent pHi increase was also Na+ and amiloride sensitive, but high HCO3- concentrations increased pHi even in the absence of Na+, K+, or Cl-, and in the presence of omeprazole, bafilomycin A1, or acetazolamide. We suggest that in intact frog gastric mucosa, cellular proton extrusion acidifies the interstitial pH immediately adjacent to the basolateral membrane of the oxyntic cells in the absence of a high interstitial buffer capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Cholestasis induced hyperthyroidism after liver transplantation.

We report the case of a 68-year-old woman who underwent liver transplantation because of hepatitis-C-induced cirrhosis. She developed iodine-reduced hyperthyroidism postoperatively in temporal relation with cholestatic jaundice. Hepatic biopsies revealed moderate intrahepatic cholestasis and mild lobular inflammatory infiltration with some eosinophils. No histological evidence of acute graft rejection or reactivated hepatitis was found. Treatment with methimazole markedly reduced the serum parameters of cholestasis which, after subtotal thyroidectomy, returned to normal. Liver function recovered, as confirmed by repeated aminopyrine breath tests.

Aged↗
PubMed1995

Pantoprazole and ranitidine in the treatment of acute duodenal ulcer. A multicentre study.

BACKGROUND: Pantoprazole is a new substituted benzimidazole that inhibits the parietal cell H+,K(+)-adenosine triphosphatase. METHODS: Pantoprazole (40 mg) was compared with ranitidine (300 mg) in the treatment of acute duodenal ulcer. Two hundred and sixty-six patients with endoscopically diagnosed duodenal ulcers entered this multicentre, double-blind study. The primary efficacy variable was complete ulcer healing at 2 weeks; treatment then continued for a further 2 weeks if ulcers were unhealed. RESULTS: After 2 weeks 112 of 164 (68%) patients in the pantoprazole group had healed ulcers, compared with 36 of 81 (44%) taking ranitidine (p < 0.001). After 4 weeks the cumulative healing rates were 96% and 85% (p < 0.01). Improvement in ulcer pain was also significantly better with pantoprazole than with ranitidine (81% versus 62% with no pain at 2 weeks, p < 0.01). CONCLUSIONS: Pantoprazole is clinically superior to ranitidine in the treatment of acute duodenal ulcer, in terms of both healing and symptom relief.

2-Pyridinylmethylsulfinylbenzimidazoles↗