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Biomedical subjects

M Classen

Publications and source records attributed to M Classen.

At least 109 records · Page 6Linked to original sources
PubMed1992

Endosonographic diagnosis of submucosal upper gastrointestinal tract tumors.

Endoscopic ultrasound (EUS) was performed in 37 patients with upper gastrointestinal tract submucosal tumors (SMT). Fourteen of these were located in the esophagus, 20 in the stomach, and 3 in the duodenum. In 26 patients histologic confirmation was achieved by operation (n = 15) or biopsy/puncture (n = 11). EUS was able to visualize all tumors and, with one exception, determined their originating wall layer correctly. It became evident that myogenic tumors arise from the echo-poor layers (second layer and fourth--that is, muscularis propria) and that other lesions, such as cysts or fibromas, originate from the third, echo-rich layer (submucosa). Tumor size was correctly (+/- less than 5 mm) predicted in 87% of cases. Computed tomography, performed in 22 patients, was successful in visualizing the SMT in only two-thirds of cases. No single endosonographic criterion could be obtained which enabled accurate differentiation between benign and malignant SMT. However, from a clinical point of view, it seems reasonably safe to regard smaller (less than 3 cm), smoothly demarcated SMT as benign and follow them up by repeated EUS, especially in patients at risk for surgery. Larger masses (greater than 5 cm) and those with irregular borders should be suspected of being malignant. In the future, application of new, small ultrasound probes that can be used during conventional endoscopy (two SMT were visualized successfully) may greatly simplify the procedure.

Diagnosis, Differential↗
PubMed1992

Nonspecific immunostimulation with low doses of cyclophosphamide (LDCY), thymostimulin, and Echinacea purpurea extracts (echinacin) in patients with far advanced colorectal cancers: preliminary results.

Outpatients (n = 15) with metastasizing far advanced colorectal cancers received immunotherapy consisting of low-dose cyclophosphamide (LDCY) 300 mg/m2 every 28 days i.v., thymostimulin 30 mg/m2, days 3-10 after low-dose cyclophosphamide i.m. once daily, then twice a week, and echinacin 60 mg/m2 together with thymostimulin i.m. All patients had had previous surgery and/or chemotherapy and had progressive disease upon entering the study. Two months after onset of therapy a partial tumor regression was documented in one and a stable disease in 6 other patients by abdominal ultrasonography, decrease of the tumor markers carcinoembryonic antigen (CEA), CA 19-9, CA 15-3, and/or chest roentgenography, which may also be attributed to the natural course of disease. Mean survival time was 4 months, 2 patients survived for more than 8 months. Immunotherapy was well tolerated by all patients without side effects.

Adjuvants, Immunologic↗
PubMed1992

[Clinical relevance of endosonography in diagnosis of pancreatobiliary diseases].

Endoscopic ultrasonography allows a high-resolution imaging of the pancreas and the extrahepatic biliary tract due to the high ultrasonic frequencies employed. This is of clinical benefit in the delineation of small pancreatic carcinomas complementary to ERCP and in the preoperative localization of endocrine tumors of potential pancreatic origin. Endosonography is the most accurate method presently available for the local staging of pancreatobiliary malignancy and thus helps avoiding diagnostic laparotomy for staging purposes. The role of endoscopic ultrasonography in the diagnosis of benign diseases such as chronic pancreatitis and choledocholithiasis has not yet fully been established. Endosonography, however, has no role in the differential diagnosis of benign and malignant disorders of the pancreas and biliary tract.

Ampulla of Vater↗
PubMed1992

[Endosonography in gastroenterology--an intermediate evaluation].

Endoscopic ultrasonography has widened the diagnostic spectrum of gastrointestinal disorders in two respects: For the first time it became possible to visualize the gastrointestinal wall with its layer structure. EUS was shown to be highly accurate in the local staging of gastrointestinal tumors (T and N stage). The clinical relevance of endosonography derives from stage-dependent treatment protocols selecting patients for different forms of tumor therapy. The second advantage of endosonography is a high-resolution imaging of the pancreas enabling the detection of small lesions (e.g. endocrine tumors). Endoscopic ultrasonography is furthermore the most reliable method for local staging of pancreatic and ampullary carcinoma. The role of endosonography in benign gastroenterological disorders is less well established. With the increasing use of laparoscopic surgery endosonography may become even more important in the future.

Diagnosis, Differential↗
PubMed1991

[Endoscopic papillotomy (sphincterotomy) in the 1990-s].

This review summarizes the past history and presence of endoscopic papillotomy (EPT, sphincterotomy) in the treatment of biliary and pancreatic tract diseases. The indications of the different techniques used, and the comparison of the effectiveness of EPT with that of the traditional surgical treatment is also discussed. Based on the results, EPT is an up-to-date technique with good effectiveness, low risk for patients and widening indication range. EPT in the future, will play a determining role in the effective treatment of biliary and pancreatic tract diseases.

Ampulla of Vater↗
PubMed1991

Neuropeptide Y and food intake in fasted rats: effect of naloxone and site of action.

Central administration of neuropeptide Y (NPY) induces food intake in freely feeding animals and this effect is mediated by hypothalamic sites. Little is known, however, about the effect of NPY on food intake and site of action in food-deprived animals. To examine this further, 24-h fasted rats received injections of saline or NPY into the lateral cerebral ventricle (10 micrograms/10 microliters; n = 8) or into the lateral (LH) or ventromedial hypothalamus (VMH) (1 microgram/0.5 microliters; n = 44). In addition, intracerebroventricular (i.c.v.) injections of NPY were carried out with or without i.c.v. naloxone (25 micrograms), a specific opioid receptor antagonist. During the first 40 min food intake was not different with or without NPY. After 60 and 120 min, food intake was 5.9 +/- 0.4 g and 8.3 +/- 0.6 g with i.c.v. saline which was significantly augmented by i.c.v. NPY to 8.7 +/- 0.9 g and 14.4 +/- 1.5 g, respectively (P less than 0.05). This increase in food consumption was due to a prolongation of feeding time. The opioid receptor antagonist naloxone significantly augmented latency to feed, both in the absence and presence of NPY (8.0 vs 1.7 min or 14.7 vs 2.8 min, respectively) and abolished the NPY-induced increase in food intake. Following intrahypothalamic injection of NPY, an increase in food intake (greater than 20%) was observed in 50% of the histologically identified LH and VMH sites, but only in 15% of the injection sites outside the LH/VMH.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

A major fraction of human intraepithelial lymphocytes simultaneously expresses the gamma/delta T cell receptor, the CD8 accessory molecule and preferentially uses the V delta 1 gene segment.

The frequency of T cell receptor (TcR) type and the variable gene segment expression in human intraepithelial lymphocytes (IEL) from the large intestinal mucosa were studied by flow cytometry and immunohistochemistry, and compared to those in peripheral blood lymphocytes (PBL) - or lamina propria lymphocytes (LPL). Employing anti-gamma/delta TcR and anti-alpha/beta TcR monoclonal antibodies (mAb), flow cytometric analysis revealed that a large fraction of IEL (37%) are gamma/delta T cells, whereas within LPL and PBL gamma/delta T cells comprise a minor population (4.6% and 3.8% respectively). At these sites the number of gamma/delta T cells labeled with anti-CD8 mAb were 58.3% (IEL), 43.3% (LPL) and 24.4% (PBL). In situ staining of serial sections of large intestine confirmed these results. Hence, these data suggest a selective accumulation of CD8+ gamma/delta T cells in the human epithelium of the large intestine. Furthermore, analysis of gamma/delta TcR bearing IEL+ disclosed a marked preponderance of cells using the V delta 1 gene segment, whereas gamma/delta TcR+ PBL preferentially express V delta 2. Strikingly, the majority of these V delta 1+ IEL bear the CD8 molecule on their surface. These results are taken as evidence for a selective localization of V delta 1+ CD8+ gamma/delta T cells in the epithelium of the large intestine.

Adult↗
PubMed1991

The effect of glucose and insulin on vagally induced gastrin, bombesin-like immunoreactivity and somatostatin secretion from the perfused rat stomach.

Previous studies in the isolated perfused rat stomach have shown that elevated glucose and insulin concentrations modulate BLI and somatostatin release during arterially administered peptidergic stimuli. In the present study the effect of elevated levels of glucose or insulin was examined on vagally induced changes of gastrin, somatostatin and BLI secretion. The lumen of the stomach was perfused with saline pH 7 or pH 2. Vagal stimulation (5 Hz, 1 msec, 10V) increased gastrin and BLI secretion and inhibited somatostatin release. The increase of the perfusate glucose concentration from 100 mg/dl to 150 or 300 mg/dl or the addition of insulin (100 microU/ml) augmented vagally stimulated gastrin release at luminal pH 7 but not pH2. Vagally induced inhibition of somatostatin was attenuated by both concentrations of glucose at either luminal pH while insulin had no effect. BLI secretion was affected neither by elevated glucose nor by insulin. On the other hand, the noncholinergic component of vagally induced BLI secretion in the presence of atropine was augmented by insulin. These data demonstrate that glucose and insulin can modulate vagally activated gastric neuroendocrine functions which could be of relevance during the ingestion of carbohydrate containing meals.

Animals↗
PubMed1991

Gastric fundus impression caused by splenic vessels: detection by endoscopic ultrasound.

When a submucosal impression of the stomach fundus is seen during upper GI endoscopy, a true submucosal tumor can reliably be differentiated from an extragastric impression by endoscopic ultrasound (EUS). We report on 15 patients in whom EUS identified splenic vessels near the splenic hilum causing an impression of the posterior wall of the gastric fundus. Neither by EUS nor conventional ultrasound, computed tomography or clinical follow-up, was a tumor in the stomach or upper abdomen that could have been the cause of the gastric wall impression, identified. Two of the 15 patients had portal hypertension with multiple intra-/paramural venous collateral vessels. Twenty patients examined for other reasons and 10 patients with portal hypertension but without fundic impressions, served as controls: In these cases the splenic vessels were shown by EUS to follow a course more distant to the gastric wall. Thus, normal vascular structures should be included in the differential diagnosis of gastric fundus impression detected by endoscopy.

Diagnosis, Differential↗
PubMed1991

The quality of gastroenterological reports based on free text dictation: an evaluation in endoscopy and ultrasonography.

The majority of physicians consider the use of free dictation for medical reports to be essential in many domains. One of the main criticisms of structured data entry is the possible lack of flexibility and completeness. Electronic documentation systems exist for endoscopy and ultrasonography examinations which are based on structured input as well as on free dictation. Endoscopy and ultrasonography reports based on free dictation were evaluated for omissive errors. The data evaluated was drawn from a database of 18,239 gastroscopy and 3,340 colonoscopy reports dictated by 28 physicians over 74 months, and 18,834 ultrasonography reports dictated by 37 physicians over 42 months. The error rates varied from 0% to 41.8% depending upon the particular feature and the particular examination, but were usually below 15%. The results were independent of the experience of the examiner. This study provides baseline measurements of omissive error rates for selected findings in gastrointestinal endoscopy and abdominal ultrasonography which can be used as standards for the development and evaluation of systems for collection of clinical data.

Database Management Systems↗
PubMed1991

An unusual case of active tuberculosis of the oesophagus in an adult.

A case is reported of a 56-year-old woman of Libyan origin presenting with dysphagia, retrosternal pain and weight loss. Oesophago-gastroduodenoscopy revealed an ulcerated tumor in the upper oesophagus strongly suggesting a malignancy. A positive Mendel-Mantoux test along with histological evidence of epitheloid cell granulomas and clinical findings consistent with pulmonary and lymph node tuberculosis led to the presumptive diagnosis of oesophageal tuberculosis. The diagnosis was later confirmed by positive bacteriological cultures of oesophageal biopsies and gastric washings. It is very unusual for dysphagia to be the presenting symptom of active adult tuberculosis. Oesophageal tuberculosis is extremely rare and must be distinguished predominantly from oesophageal carcinoma.

Deglutition Disorders↗