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Biomedical subjects

M Classen

Publications and source records attributed to M Classen.

At least 55 records · Page 3Linked to original sources
PubMed2000

The role of diet and lifestyle measures in the pathogenesis and treatment of gastroesophageal reflux disease.

Gastroesophageal reflux disease (GERD) and the complications associated with it are very common in the Western world. There has been speculation for many years that certain dietary and lifestyle factors may play a role in the pathogenesis or course of GERD. However, a wide-ranging review of the available data reveals conflicting findings regarding the impact of most of these factors. In addition, the majority of the studies concerned have been based on small numbers of patients, and in most cases these studies do not meet the criteria for evidence-based medicine. Consequently, any advice given on modifying diet and/or lifestyle in the management of GERD represents a form of empirical therapy. A general consensus on the control of GERD through alterations in diet and lifestyle factors could hardly be based on the results of clinical or outcome studies. In practice, however, the treatment of GERD is oriented toward the individual patient's symptoms, and includes offering reasonable advice on how to adapt to personal dietary intolerance and lifestyle factors.

Feeding Behavior↗
PubMed1999

Clinical relevance of the Helicobacter pylori gene for blood-group antigen-binding adhesin.

Infection with Helicobacter pylori is associated with different human gastric diseases. Biochemical studies, in vitro adherence assays, and in vivo animal models revealed that epithelial attachment of H. pylori can be mediated by the blood-group antigen-binding adhesin (BabA) targeting human Lewis(b) surface epitopes. Studies with transgenic mice expressing the Lewis(b) epitope have shown that such attachment can alter disease outcome. In the current study, the presence of the babA2 gene encoding the adhesin was investigated in clinical isolates from a German population by using PCR and reverse transcription-PCR. A positive genotype was correlated to allelic variations in the genes encoding VacA and CagA and also to the prevalence of duodenal ulcer, distal gastric adenocarcinoma, mucosa-associated lymphoid tissue lymphoma, and antral gastritis. The presence of babA2 was significantly associated with duodenal ulcer (P = 0.0002) and adenocarcinoma (P = 0.033). In contrast, type 1 strains (vacAs1- and cagA-positive) were associated with only duodenal ulcer (P = 0.004) but not adenocarcinoma (P = 0.235). Genotype presence of babA2, vacAs1, and cagA ("triple-positive" strains) showed a highly significant correlation to the prevalence of ulcer (P = 0.000002) and adenocarcinoma (P = 0.014) and discriminated significantly better between disease outcome than did the current type 1 classification. These results indicate that the babA2 gene is of high clinical relevance and would be a useful marker to identify patients who are at higher risk for specific H. pylori-related diseases.

Adhesins, Bacterial↗
PubMed1999

[Prospective Epidemiologic Study of Epigastric Discomfort (PRESTO). Ground work and preliminary results].

BACKGROUND AND OBJECTIVE: Symptoms of dyspepsia (indigestion; upper abdominal discomfort) are one of the most frequent reasons for consulting a general practitioner or internist. Yet there are no up-to-date national data on the epidemiology and course of this symptom complex. PATIENTS AND METHODS: In an open, prospective, multicentre, epidemiological study (PRESTO) 3016 patients with the suspected diagnosis of "functional dyspepsia" (1228 males, 1788 females, mean age 50 +/- 15 years) were followed for 2 years by 983 physicians in private practice (general practitioners or specialists in internal medicine). Patients with proven gastro-oesophageal reflux or peptic ulcer were excluded. Treatment was at the discretion of the physician. Patients were seen after one month (if under treatment) and then at 6, 12, 18 and 24 months. In addition to personal data, (1) symptoms, diagnosis and treatment of the dyspepsia, (2) socioeconomic aspects and (3) any limitations and the quality of life of each patient were recorded in a standard manner. RESULTS: At the first interim analysis more than half the patients judged there situation to be one of "chronic stress" or having to cope with a stressful event; nearly 50% thought this to be the cause of the symptoms. Concomitant illnesses were present in 63% of patients. Oesophagogastroduodenoscopy with subsequent medication was performed in 20.6%, a trial of medication (usually drugs stimulating gastric motility) in 65%. No medication was initially given to 14.4% of patients. The most common symptoms were feeling of fullness (92.9%, epigastric pressure sensation (91.5%) and flatulence (87.4%). CONCLUSION: These preliminary results indicate that a large epidemiological study can be performed by general practitioners and has advantages over the more usual method of enquiry by telephone. Dyspepsia exerts an unusually high degree of stress and results in considerable demands on medical facilities.

Adolescent↗
PubMed1999

[Metal stents in gastroenterology].

Self-expanding metal stents have, when introduced in their constrained form through gastrointestinal and biliary strictures, a relatively small diameter. Once placed through the stricture and released, however, they expand to a much larger internal diameter, thus giving rise to sufficient palliative reopening of these strictures. Since metal stents are usually not removable, their primary use has been in malignant stenoses. Benign strictures should be treated with metal stents only in exceptional situations. For palliation of dysphagia in esophagocardial malignancies, metal stents have been shown to be associated with significantly fewer initial complications on placement than plastic tubes. The long-term fate of both stent types seems to be similar. In the palliation of malignant jaundice, metal stents were demonstrated to have a significantly longer patency rate, resulting in a favourable cost-benefit ratio despite the high price of metal stents. Continued developments are necessary to further reduce long-term complications and effectiveness.

Bile Duct Neoplasms↗
PubMed1999

Performance, patient acceptance, appropriateness of indications and potential influence on outcome of EUS: a prospective study in 397 consecutive patients.

BACKGROUND: Although there is a large body of data on the accuracy of endoscopic ultrasonography (EUS) in the diagnosis and staging of various gastroenterological disorders, little has been published on the influence of EUS in the management of patients. Data on the performance of EUS and patient acceptance are also sparse. METHODS: During a 10-month period, all consecutive EUS examinations were categorized by the examiner according to the appropriateness of the indications. Prior examinations, performance of EUS (duration, premedication, complications), and patient acceptance (assessed using a questionnaire by an independent investigator) were recorded. A mean of 2 months after the procedure, referring physicians were asked about the extent to which the EUS results had influenced their further diagnostic and therapeutic approach. RESULTS: A total of 397 patients were included; they were referred for EUS after a mean of 1. 8 specific tests had been performed. The appropriateness of the indications for EUS was categorized as "classic," "useful," and "potentially useful" (categories 1 to 3) in 81% of cases. The referring physicians replied that EUS had provided useful additional information in 55% of cases; the EUS findings prompted further tests in 22% and made further examinations unnecessary in 30%. A change in therapy was believed to be directly due to EUS in only 6% of cases. The duration of the EUS examinations ranged from a mean of 8.1 minutes (esophageal indications) to 18.9 minutes (biliary indications). There were no complications. In patients who were able to remember the EUS examination (42%), 90% found it tolerable, and 83% of all the patients interviewed were willing to have the examination repeated with the same level of sedation. CONCLUSIONS: EUS is a safe examination that can be carried out within a reasonable time frame by experienced examiners and without significant patient discomfort when performed under conscious sedation. With regard to patient management, EUS mainly influences further diagnostic tests.

Adolescent↗
PubMed1999

Albumin dialysis: effective removal of copper in a patient with fulminant Wilson disease and successful bridging to liver transplantation: a new possibility for the elimination of protein-bound toxins.

BACKGROUND: Acute liver failure may be the first manifestation of Wilson disease. If copper elimination fails, liver transplantation is the only remaining therapeutic option. Albumin dialysis, a new method for the removal of protein-bound toxins, was performed in a patient with fulminant Wilson disease. METHODS: An 18-year-old man with Wilson disease presented with hyperacute liver failure, hepatic encephalopathy III, oligo-anuric renal failure, haemolytic anaemia, rhabdomyolysis, pancreatitis and thrombocytopenia. He was treated with albumin dialysis using a 44 g/l albumin-containing dialysate and a slow dialysate flow rate (1-2 l/h). The other details of the technique used are similar to routine continuous veno-venous haemodiafiltration. RESULTS: One hundred and five milligrams of copper were removed by albumin dialysis within the first six treatments, resulting in normalisation of blood-copper levels. Successful treatment of the multiorgan failure was achieved. Hepatic encephalopathy improved within 2 days. The patient initially refused liver transplantation. Therefore 35 additional albumin dialysis treatments were performed. Forty-three grams of bilirubin (an indicator of detoxified substances in the liver) and 196 mg of copper were removed. Multiorgan failure, in particular hepatic encephalopathy, did not recur during 59 days of treatment. Eventually, the patient agreed to liver transplantation and that was successful. CONCLUSION: Albumin dialysis is a new method for the effective treatment of fulminant Wilson disease, resulting in the removal of protein-bound toxins copper and bilirubin. It may serve as a new treatment option in hyperacute liver failure of other origin, acting as an extracorporeal detoxifier.

Adolescent↗
PubMed1999

Initial experience with a new Yamakawa-type prosthesis for long-term percutaneous transhepatic drainage.

BACKGROUND AND STUDY AIMS: In a previous study evaluating the problems of long-term percutaneous transhepatic biliary drainage (PTBD) using Yamakawa-type prostheses in patients with benign and malignant stenoses, breakage of the tube proved to be a serious problem, occurring in 19.7 % of PTBD exchanges. As a consequence of these results, a new PTBD tube made of Tecothane has been developed. PATIENTS AND METHODS: From September 1997 to September 1998, this new PTBD tube was applied in 64 patients (39 men, 25 women; median age: 70, range 29-89) in the treatment of benign (n = 30) or malignant stenoses (n=31; three stenoses remained indeterminate), and the course was followed. RESULTS: A total of 134 stent exchanges were performed, 52 of these being ahead of schedule (39 %). Not a single case of breakage occurred. However, other PTBD-related problems remained unchanged. Patients accepted the new prosthesis very well; among 19 patients who had experience of both the new one and the conventional one, 11 had preferences-eight for the new one and three for the old one. CONCLUSIONS: This new Tecothane prosthesis has solved the problem of PTBD breakage, which was often accompanied by serious problems. As was to be expected, other PTBD-related problems were not substantially affected. Nevertheless, this new tube represents progress in the percutaneous treatment of biliary stenoses.

Adult↗
PubMed1999

Long-term results of endoscopic and percutaneous transhepatic treatment of benign biliary strictures.

BACKGROUND AND STUDY AIMS: Benign biliary strictures, mostly associated with biliary surgery, are of growing importance for the therapeutic endoscopist. In the short term, endoscopic therapy has success rates similar to those of surgery. With regard to the long-term results, fewer data are available, particularly concerning forms of treatment including percutaneous transhepatic biliary drainage (PTBD) as an additional tool. The present study was aimed at allowing evaluation of the short and long-term results of endoscopic and percutaneous treatment in patients with benign biliary strictures. PATIENTS AND METHODS: The charts of 40 consecutive patients treated during the period 1992-1994 (12 men, 28 women; median age 60.5 years, range 24-86) were analyzed retrospectively. Long-term follow-up was carried out by direct contact. In almost all of the cases, the endoscopic treatment consisted of papillotomy and stenting (single stent treatment 10 or 11.5 Fr); Yamakawa-type prostheses (14 or 16 Fr) were used in the PTBD patients. RESULTS: The primary treatment was successful in 37 of the 40 patients, including nine of 21 patients (43 %) treated endoscopically and 28 of 31 patients (90%) treated using the percutaneous approach. The complication rates after endoscopic retrograde cholangiopancreatography (ERCP) were 14%, compared with 26% after PTBD. Relief of the stricture was achieved in 25 patients after a median period of stent treatment of nine months (range 3-44), while recurrences were seen in six patients with stents in place for only 4.5 months (range 1-8), and in one patient with a metal stent. Therapy failed in two patients, and three were lost to follow-up. Serious long-term complications were rare, but there was a fatal complication in one patient with metal stents. The follow-up period was 44 months (range 11-66). Three patients underwent successful primary surgery, and three more underwent successful surgery after stricture recurrence; all were free of complaints after 49 months (range 40-44). CONCLUSIONS: Endoscopic and percutaneous treatment of benign biliary strictures is not only a short-term treatment, but also an adequate long-term therapeutic alternative to surgery, with tolerable complication rates. The period of stenting appears to influence the outcome, and the diameter of the stents used also probably plays a role. Prospective studies are required for further evaluation of these observations.

Adult↗
PubMed1998

[Polyposis of the gastrointestinal tract as a manifestation of diffuse follicular lymphatic hyperplasia].

HISTORY AND ADMISSION FINDINGS: A 21-year-old previously healthy Turkish man who had been living in Germany for 15 years was admitted because of worsening cramp-like abdominal pain with nausea, vomiting and watery diarrhoea. Palpation elicited diffuse muscular guarding over the entire abdomen and a mass of about 8 cm in the right lower abdomen. INVESTIGATIONS: Abnormal laboratory results were erythrocyte sedimentation rate (55 mm), C-reactive protein (6.2 mg/dl), total bilirubin (2.1 mg/dl), creatine kinase (137 U/l) and thymidine kinase (5.5 U/l). There was a slight leucocytosis (13,700/microliter) and mild anaemia (haemoglobin 13.4 g/dl) with a normal differential count. Listeria ivanovii was repeatedly cultured from stool. Ultrasonography and computed tomography of the abdomen demonstrated a 6 cm mass in the right lower abdomen, splenomegaly (15.5 x 5 cm) and several lymphomas, up to 1.8 cm in diameter. Endoscopy revealed dense, in part grass-like, polyps, 3 to 6 mm deep, in the mucosa from the terminal ileum to the rectum, and to a lesser extent also in the duodenum. Histological examination of the polyps demonstrated diffuse follicular hyperplasia without evidence of malignancy. TREATMENT AND COURSE: On antibiotic treatment with ofloxacin (2 x 400 mg intravenously) the symptoms quickly regressed, but the endoscopic findings remained unchanged. CONCLUSION: Diffuse follicular lymphatic hyperplasia manifested itself in this patient as diffuse gastrointestinal polyposis. Listeria ivanovii cannot be ruled out as a causative factor.

Abdominal Pain↗
PubMed1998

Randomized study of intracorporeal laser lithotripsy versus extracorporeal shock-wave lithotripsy for difficult bile duct stones.

BACKGROUND: Endoscopic treatment modalities are well established for the removal of bile duct stones. For the small percentage of stones that are difficult or impossible to extract by conventional means, more sophisticated endoscopic techniques or associated modalities such as intracorporeal laser lithotripsy (ILL) and extracorporeal shock wave lithotripsy (ESWL) have to be applied. Little is known, however, about the relative value of these different techniques. We therefore compared endoscopic ILL with ESWL in patients with difficult bile duct stones in a prospective randomized study. METHODS: The study included 60 patients (35 women; mean age 70+/-15 years) with bile duct stones in whom standard extraction failed (n=33) or in whom the papilla was not accessible, thus requiring percutaneous access (n=27). They were randomized to receive ESWL under fluoroscopic targeting (maximum discharge number per session: 6000) or ILL using a pulsed dye laser with an automatic stone recognition system, which was mostly performed (28 of 30 cases) under cholangioscopic control. Endoscopic removal of fragments was attempted within the subsequent (ESWL) or the same (ILL) session. Failure was defined as failure to remove all ductal stones/fragments after a maximum of three lithotripsy sessions. RESULTS: There were no statistical differences in background variables between the two groups. Bile duct clearance was achieved in 22 of 30 patients (73%) in the ESWL group and in 29 of 30 patients (97%) in the ILL group (p < 0.05). The number of treatment sessions (ESWL 3.0+/-1.3; ILL 1.2+/-0.4; p < 0.001) and the duration of treatment (ESWL 3.9+/-3.5 days; ILL 0.9+/-2.3 days; p < 0.001) were also significantly different in favor of ILL. Two minor complications occurred in each group; there was no 30-day mortality. Crossover therapy to ILL led to stone removal in seven of the eight cases in which ESWL failed, whereas ESWL fragmented the stone in the single patient in whom ILL failed. CONCLUSIONS: ILL is more effective in the treatment of difficult bile duct stones than ESWL in terms of stone clearance rate and treatment duration.

Aged↗
PubMed1998

Biomagnetic 3-dimensional spatial and temporal characterization of electrical activity of human stomach.

Biomagnetic measurements are based on the noninvasive recording of magnetic signals produced by biological sources such as nervous system and muscle. The aim of this study was to obtain multichannel magnetic field recordings from the human gastrointestinal tract and to localize the sources of these signals three-dimensionally. The magnetic field was recorded in eight human healthy subjects using a sensor array with 37 superconducting quantum interference devices (SQUIDs); an electrogastrogram was recorded simultaneously. Biomagnetic source localization was carried out with an iterative nonlinear optimization algorithm using the model of an equivalent current dipole (ECD) and correlated to magnetic resonance imaging (MRI) in four volunteers. Magnetogastrograms and electrogastrograms demonstrated a similar frequency distribution with a peak at 3/min. In all subjects the centers of the calculated dipoles plotted vs time showed a characteristic migration across the stomach area. One volunteer demonstrated tachygastric episodes, during which his magnetic field amplitudes increased fivefold and his dipole migration disappeared. In absence of an attack his recordings changed to normal. This demonstrates multichannel magnetic recordings can be used to localize the sources of the biomagnetic field, which could be useful for the understanding of motility disturbances.

Adult↗
PubMed1998

Significance of antibodies to the recombinant E2 protein of hepatitis G virus in haemodialysis patients.

Patients on maintenance haemodialysis represent a high-risk group for parenterally transmitted viral infections, such as hepatitis B, C and G. In addition to hepatitis G virus (HGV) (GBV-C) RNA, analysed in previous studies, we characterized the seroprevalence rates of antibodies to the putative E2 protein (anti-E2) of HGV in a German cohort of patients on maintenance dialysis (n = 72) in comparison to healthy blood donors (n = 100). The presence of anti-E2 and/or HGV RNA as indicators of present or past HGV infection could be demonstrated in 34.7% of patients and in 16% of the blood donors (P < 0.01). The infection rates with HGV seem to increase only during the first 6 years of haemodialysis. The simultaneous presence of viraemia and anti-E2 was found very rarely in patients and controls. Therefore, the emergence of anti-E2 indicates clearance of HGV viraemia. In conclusion, patients on haemodialysis are at high risk of acquiring HGV infection, but a chronic carrier state with viraemia is rare. The risk of infection is not strictly correlated with the duration of dialysis.

Antibodies, Viral↗