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Biomedical subjects

C Niederau

Publications and source records attributed to C Niederau.

At least 109 records · Page 6Linked to original sources
PubMed1994

Clinical spectrum and management of haemochromatosis.

Haemochromatosis is one of the most common inborn errors of metabolism. In prospective epidemiological studies the frequency of haemochromatosis is 0.0037 (76/20333 subjects) for homozygotes which corresponds to a gene frequency of 0.061 and a frequency of heterozygotes of 0.115. Abnormality in liver function tests, weakness and lethargy, skin hyperpigmentation, diabetes mellitus, arthralgia, impotence and ECG abnormalities are the most frequent findings and symptoms at diagnosis. In recent years about 50% of patients were detected without having liver cirrhosis and 20% of patients did not have any symptoms and pathology except iron overload. Survival analyses in long-term studies showed that in the absence of cirrhosis and diabetes, iron removal by phlebotomy therapy prevents further tissue damage and guarantees a normal life expectancy. Patients with massive and long-lasting iron overload had a worse prognosis than those with less severe iron excess. Iron removal in general ameliorated liver disease, weakness and cardiac abnormalities, and also prevented the progression of endocrine alterations. Therapy, however, did not influence insulin-dependent diabetes. Most deaths in patients with hereditary haemochromatosis were caused by liver cancers which often occurred many years after complete iron removal. In patients with haemochromatosis, liver cirrhosis, cardiomyopathy, and diabetes mellitus are also significantly more frequent causes of deaths when compared with the general population. Further strategies have to evaluate the design of screening programmes in order to diagnose more patients in the precirrhotic and asymptomatic stage.

Bloodletting↗
PubMed1994

The effect of L-buthionine-[S,R]-sulfoximine on the pancreas in mice. A model of weakening glutathione-based defense mechanisms.

L-Buthionine-[S,R]-Sulfoximine (BSO) decreases glutathione levels in various organs by inhibition of gamma-glutamylcysteine synthetase. We have examined the levels of total glutathione and oxidized glutathione in the pancreas of mice, as well as serum amylase and pancreatic histology, after BSO administration in two different ways. The injection of a single dose of BSO (5 mmol/kg body wt) decreased total glutathione to 10% of the control value. A similar depletion was observed after 24 h of oral administration of a 10 mM BSO solution, without changes in the levels of oxidized glutathione. BSO-induced pancreatic glutathione depletion--even if maintained for up to 14 d--did not cause morphological alterations of the pancreas or hyperamylasemia. Thus pancreatic glutathione depletion in itself does not lead to pancreatitis, although during development of experimental acute pancreatitis, glutathione depletion has been described. BSO might be used in animal models to weaken the glutathione-based acinar defense mechanisms against oxidant stress or to alter other physiologic processes in which glutathione is involved.

Acute Disease↗
PubMed1994

Inhibition of exocrine pancreatic secretion by somatostatin and its analogues.

The stimulation of exocrine pancreatic secretion has extensively been studied in the past. On the other hand, little is known about the factors and mechanisms which regulate inhibition of exocrine pancreatic secretion. This review, therefore, focuses on somatostatin as one candidate of several peptides which may physiologically mediate inhibition of pancreatic secretion and on its possible mode of action. Somatostatin probably inhibits pancreatic exocrine secretion by a variety of mechanisms which depend on the species and the type of secretion studied (postprandial vs. interdigestive secretion, protein vs. bicarbonate secretion): Somatostatin may act via inhibition of the release of circulating hormones such as cholecystokinin (CCK) and secretin or via intrapancreatic inhibition of the release or action of CCK. Somatostatin may inhibit acetylcholine release from nerve terminals which express specific somatostatin receptors or directly affect the secretory response of the acinar cells via specific somatostatin receptors by a reduction of intracellular cAMP. Somatostatin may also indirectly alter the pancreatic response to a meal by its extrapancreatic effects, e.g. inhibition of gastric secretion, gastric emptying, gallbladder emptying and gastrointestinal motility.

Animals↗
PubMed1994

Free radical science: the long road from basic science to clinical medicine.

The process of translating our exploding knowledge in the area of free radicals and antioxidants from basic science to clinical medicine may take longer than many scientists and physicians had hoped. The field of "oxidant/antioxidant" science is only one example of how the translation of knowledge from controlled molecular or cellular systems to applications in an organ or even a complex animal or human being, requires an enormous amount of classical pathophysiological work. The articles on the special topic of the role of free radicals in gastroenterological and hepatological diseases will, it is hoped, contribute to this process.

Antioxidants↗
PubMed1994

Oxidative stress-induced changes in pancreatic acinar cells: insights from in vitro studies.

Oxidative stress is regarded a major factor in the pathogenesis of both acute and chronic pancreatitis. The mechanisms by which free radicals damage the acinar cells are not yet clear. Standard models of oxidative stress were applied to investigate the susceptibility of isolated rat pancreatic acinar cells and zymogen granules to oxidant attack and to explore the potential of several antioxidants and radical scavengers to prevent such injury. Short-term peak production of free radicals by xanthine oxidase was more injurious to the acinar cells than continual radical generation at a lower level by iron/adenosine diphosphate. Isolated zymogen granules were much more susceptible to oxidative damage that isolated acinar cells. In both models, a combination of catalase and superoxide dismutase effectively prevented cell damage. In contrast, the classical hydroxyl radical scavengers mannitol, dimethyl sulphoxide and dimethyl thiourea, as well as the iron chelator deferoxamine were ineffective and at a higher concentration were even toxic. The novel low molecular weight 21-aminosteroid substances called "lazaroids" showed a highly protective potential when applied at a concentration of 1-50 mumol/l and are therefore considered to be the substances most likely to protect the pancreas cells against oxidative injury. Higher concentrations of the lazaroids, however, also caused additional damage to the cells. The results indicate that multiple radical species and several mechanisms are involved in oxidative injury to the pancreatic acinar cell. From present in vitro data, no single substance can be recommended for use in animal experiments or human studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMed1994

[Endoscopy in the intensive care unit].

The present study retrospectively evaluates all endoscopies performed on a medical intensive care unit during the period from 1986 to 1992. During these seven years, 415 endoscopies were performed of which 77.8% were done as an upper gastrointestinal endoscopy. The most frequent findings consisted in esophagitis (23.6%), ulcers of the stomach or duodenum (20.2%), esophageal varices (10.1%) and erosive-hemorrhagic gastritis (9.6%). More than 2/3 of all endoscopies were performed because of an gastrointestinal bleeding with upper bleeding being three times more frequent than lower bleeding. The endoscopy was able to identify the cause and site of bleeding with certainty or high probability in 92.8%. Esophagitis was the most frequent cause of bleeding (30.7%) followed by ulcers in the duodenum and stomach (25.6%), esophageal varices (14.8%) and erosive gastritis (13.7%). In more than 90% of patients with esophagitis a nasogastric tube had been administered during the two preceding days. Therefore, the tube is probably responsible for the esophagitis. The present data show that bleeding from esophageal lesions are about ten times more frequent in patients treated in an intensive care unit when compared to data published for the general group of patients with gastrointestinal bleeding. Considering the frequency of bleeding from esophagitis in intensive care patients, an administration of a nasogastric tube should be done only when mandatory.

Critical Care↗
PubMed1994

Rhodococcus equi pneumonia in an HIV-infected patient.

We report a case of a 46-year-old HIV-infected patient suffering Rhodococcus equi pneumonia and septicaemia. After the failure of an initial antibiotic treatment, the upper lobe of the right lung was resected due to a cavitating pneumonia. After that the patient stabilized for a period of 7 months by administration of a resistogram-adapted combination of tetracycline, erythromycin and clindamycin. Due to the patient's decision, antibiotic treatment was stopped when a cytomegalovirus retinitis was diagnosed. Six weeks later new pulmonary infiltrations were diagnosed and a Rhodococcus equi bacteraemia evolved. The patient died one year after the first diagnosis of the Rhodococcus equi infection. The present case suggests that the infection with Rhodococcus equi in patients with advanced HIV infection demands permanent antibiotic prophylaxis.

AIDS-Related Opportunistic Infections↗
PubMed1993

[How many patients with chronic viral hepatitis qualify for interferon therapy? Prospective analysis of university ambulatory care].

How many patients with chronic viral hepatitis are suitable for interferon therapy? A prospective analysis of a university out-patient department. The present study prospectively analyzes 273 consecutive patients admitted to the outpatient-hepatology clinic for interferon therapy of chronic viral hepatitis from 1989 to 1991. 149/273 (54.6%) patients suffered from hepatitis-B viral infection (HBV). Of the 107 patients with NANB-hepatitis (39.2%) 103 patients finally proved to have hepatitis-C viral infection (HCV) (96.3%). In 17/273 patients (6.2%) the outside diagnosis of viral hepatitis was wrong. The percentage of men versus women was significantly greater in HBV (71.8% vs. 28.2%) than in HCV infection (52.4% vs. 47.5%) (p < 0.01; c2-test). The admittance of patients increased from 68 patients in 1989 to 88 patients in 1990 and 117 patients in 1991. The percentage of HCV-patients increased from 26.4% in 1989 to 38.6% in 1990 and 43.6% in 1991. The number of patients with HCV-infection admitted by non-university hospitals versus practitioners and internists was significantly greater in HCV-infection (48.5% vs. 51.5%) compared to HBV-infection (hospitals: 36.9%; practitioners: 63.1%) (p < 0.05). Interferon therapy was initiated in 131/252 patients (52%) with HBV- or HCV-infection. HCV-patients were treated with interferon significantly more frequently (59.2%) compared with HBV-patients (46.9%) (p = 0.05). Since interferon therapy was initiated in only about 50% of HBV- and HCV-patients, the selection criteria for such treatment need to be publicized more effectively. The marked increase in patients with HCV-infection suggests that recent improvements in serology of viral hepatitis are widely and appropriately used in clinical practice.

Adult↗
PubMed1993

Effects of bile and pancreatic digestive enzymes on permeability of the pancreatic duct system in rabbits.

In order to reproduce what may occur during the initial phase of biliary acute pancreatitis, the rabbit pancreatic duct was perfused with preincubated mixtures of bile and different digestive enzymes at low physiologic pressure. Permeability of the pancreatic duct system, serum amylase, and histological appearance of pancreatic tissue were studied after orthograde duct perfusion in the anesthetized animal. The ductal permeability was estimated by recovery of fluoresceinated dextran (molecular weight 17,200) in central venous blood following duct perfusion with this substance. Perfusion with preincubated bile failed to increase permeability significantly (11.10 +/- 3.04 nmol/L compared to 5.80 +/- 2.71 nmol/L in the control group), whereas mixtures of bile and trypsin (27.19 +/- 5.21 nmol/L), bile and lipase (16.68 +/- 3.75 nmol/L), and bile and pancreatic juice (13.92 +/- 0.48 nmol/L) caused significant increases (p < 0.05). Similar observations were made regarding serum amylase and histology. Thus, the presence of mixtures of bile with pancreatic enzymes (following their prolonged common incubation) in the absence of elevated pressure, results in an increase in duct permeability for molecules up to the size range of pancreatic enzymes and thereby may contribute to the initiation of acute pancreatitis.

Acute Disease↗
PubMed1993

Pathogenesis of genetic haemochromatosis.

Genetic haemochromatosis is an autosomal recessive inherited iron overload disease. The genetic defect and the underlying metabolic error are not known. Several observations indicate that the 2-4-fold increase of iron absorption is due to a regulatory defect of a membrane iron transport system in duodenal mucosal cells. The key pathophysiologic factor may be the increase of gut-derived non-transferrin bound iron liganded to low-molecular mass organic molecules. A putative membrane carrier protein for non-transferrin bound iron was identified and preliminary data suggest its enrichment in plasma membranes of human mucosal cells as well as in liver and other organs which are affected in genetic haemochromatosis. Cellular accumulation of ionic iron leads to peroxidative decomposition of organelle membrane phospholipids with the consequence of cell degeneration and cell death. Impairment of organ function and structural alterations such as cirrhosis of the liver are clinical manifestations.

Ferritins↗
PubMed1993

Differentiation between autoimmune hepatitis and hepatitis C virus related liver disease.

In some patients differentiation between autoimmune hepatitis and chronic viral disease may be difficult. In patients with chronic active hepatitis the coincidence of various types of autoantibodies and antibodies to hepatitis C virus (HCV-Ab) has been reported. It is important to diagnose the true etiology of the underlying liver disease because treatment for viral disease and autoimmune hepatitis is different. This paper reports about five patients who were referred to the liver outpatient clinic with the diagnosis of chronic active hepatitis. All of them had antibodies to liver-pancreas-antigen (LP-Ab) and HCV-Ab. Some authors believe that LP-Ab and anti-soluble-liver-antigen antibodies (SLA-Ab) are found with the same entity of autoimmune hepatitis. Nevertheless none of our patients had detectable antibodies against Cytokeratin 8/18, the major target antigen of SLA-Ab positive autoimmune hepatitis. Serum transaminases were elevated for more than 6 months and all patients were positive for HCV-RNA by PCR. Three patients had a history of exposure to blood products. In all five patients liver biopsy showed chronic active hepatitis compatible with chronic hepatitis C. All patients were treated with alfa-interferon. In four of five patients interferon led to improvement or normalization of serum transaminases. Thus we conclude that in a considerable number of patients with chronic active hepatitis associated with both LP-Ab and HCV-Ab, hepatitis C virus is the true etiology. Such patients with both LP-Ab and HCV-Ab may successfully be treated with alfa-interferon.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗