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Biomedical subjects

R Nitsche

Publications and source records attributed to R Nitsche.

At least 19 recordsLinked to original sources
PubMed2004

Correct interpretation of spectral interference measurements of weakly absorbing films of micrometer thickness.

We present analytical equations based on thin-film optics with which to extract the thickness of weakly absorbing films from spectral interference measurements, using only the observed constant interference frequency. It is shown that the assumption of a constant index of refraction n for the analysis of interference frequency omega 0 introduces significant errors into the thickness calculation. Instead, the first derivative of n with respect to the energy, n', has to be included as well to yield the correct film thickness, even for small values of n'. The equations presented can be used as constraints in appropriate numerical methods to improve the film thickness iteratively.

Journal Article↗
PubMed2001

Yersinia enterocolitica infection with multiple liver abscesses uncovering a primary hemochromatosis.

A 60-year-old man, although treated with antibiotics, suffered from a severe pyrexial illness of unknown origin, weight loss and intermittent abdominal pain. There was no history of diarrhea or common infections. Computed tomography and ultrasound imaging showed uncharacteristic multiple small lesions of the entire liver parenchyma. These lesions were histologically pyogenic abscesses. In addition, an unexpected, pronounced accumulation of iron pigment in hepatocytes and second degree fibrotic changes of the liver were detected. Serum iron and serum transferrin were low, but serum ferritin concentration and transferrin saturation were increased to the maximum. The demonstration of the cysteine-282-tyrosine mutation confirmed underlying primary hemochromatosis. Bacteriological cultures of the abscess material yielded Yersinia enterocolitica serotype O:3, while stool and blood cultures were negative. Antibiotic therapy with piperacillin/tazobactam and tobramycin was successful within a few days. A repeat CT scan and ultrasound imaging demonstrated complete regression of the pathologic liver morphology. The patient was discharged and treated with an orally administered fluoroquinolone for an additional 6 months. After this time the patient had no morphological residues of the infection except one enlarged lymph node near the portal vein but still was so weak that he was unable to work again. In conclusion, severe septic forms of yersiniosis are mainly found in patients with iron overload, due to a handicapped iron metabolism of the Yersinia bacteria. Mortality is high despite treatment.

Hemochromatosis↗
PubMed2000

High complication rate of bile duct stents in patients with chronic alcoholic pancreatitis due to noncompliance.

BACKGROUND AND STUDY AIMS: Biliary obstruction in chronic pancreatitis is frequently treated by endoscopic insertion of a plastic stent into the common bile duct, a therapy regarded as having a low complication rate. The aim of this study is to analyze the frequency and severity of complications caused by biliary stents in patients with chronic alcoholic pancreatitis. PATIENTS AND METHODS: We retrospectively analyzed all our patients with chronic pancreatitis (n = 14) who were provided with a plastic stent for biliary stenosis between June 1993 and December 1997. Stent exchanges were followed until December 1998. RESULTS: Stent insertion was performed without early complications and was successful in each patient. Only two patients were admitted after 3-4 months at the scheduled dates for stent exchange, both without complications. In one of these patients, the bile duct stenosis was reopened after two stent exchanges over a total period of 8 months. Most of our patients (n=12) did not come at the arranged dates for stent exchange. They were repeatedly admitted (mean 2.9 times/patient, range 1-5) as emergency cases with severe complications of biliary obstruction, such as cholangitis or biliary sepsis. Reopening of the bile duct stenosis was not achieved in these patients. CONCLUSIONS: We associate the high rate of complications with the noncompliance of our patients, who were all alcoholics. The high incidence of late complications in noncompliant patients is a limitation of biliary stenting, and appears to be potentially harmful.

Adult↗
PubMed1999

Ethanolamine ammonia-lyase has a "base-on" binding mode for coenzyme B(12).

Ethanolamine ammonia-lyase (EAL, EC 4.3.1.7) catalyzes a coenzyme B(12)-dependent deamination of vicinal amino alcohols. The mode of binding of coenzyme B(12) to EAL has been investigated by electron paramagnetic resonance spectroscopy (EPR) using [(15)N]-dimethylbenzimidazole-coenzyme B(12). EAL was incubated with either unlabeled or (15)N-enriched coenzyme B(12) and then either exposed to light or treated with ethanol to generate the cleaved form of the cofactor, cob(II)alamin (B(12r)) bound in the active site. The reaction mixtures were examined by EPR spectroscopy at 77 K. (15)N superhyperfine splitting in the EPR signals of the low-spin Co(2+) of B(12r), bound in the active site of EAL, indicates that the dimethylbenzimidazole moiety of the cofactor contributes the lower axial ligand consistent with "base-on" binding of coenzyme B(12) to EAL.

Benzimidazoles↗
PubMed1999

Binding of Cob(II)alamin to the adenosylcobalamin-dependent ribonucleotide reductase from Lactobacillus leichmannii. Identification of dimethylbenzimidazole as the axial ligand.

The ribonucleoside triphosphate reductase (RTPR) from Lactobacillus leichmannii catalyzes the reduction of nucleoside 5'-triphosphates to 2'-deoxynucleoside 5'-triphosphates and uses coenzyme B12, adenosylcobalamin (AdoCbl), as a cofactor. Use of a mechanism-based inhibitor, 2'-deoxy-2'-methylenecytidine 5'-triphosphate, and isotopically labeled RTPR and AdoCbl in conjunction with EPR spectroscopy has allowed identification of the lower axial ligand of cob(II)alamin when bound to RTPR. In common with the AdoCbl-dependent enzymes catalyzing irreversible heteroatom migrations and in contrast to the enzymes catalyzing reversible carbon skeleton rearrangements, the dimethylbenzimidazole moiety of the cofactor is not displaced by a protein histidine upon binding to RTPR.

Benzimidazoles↗
PubMed1999

Linear IgA disease associated with lymphocytic colitis.

A 66-year-old woman presented with a bullous skin eruption and chronic diarrhoea. Lesional skin showed subepidermal blistering, and direct immunofluorescence of perilesional skin revealed linear deposits of IgA at the dermoepidermal junction, establishing a diagnosis of linear IgA disease (LAD). Chronic watery diarrhoea complicated by substantial loss of body weight preceded the skin eruption for several months. On endoscopy, the colon appeared macroscopically normal. On histology, the colon mucosa showed increased numbers of intraepithelial lymphocytes and infiltrates of mononuclear cells in the lamina propria, indicative of lymphocytic colitis. Treatment with methylprednisolone and dapsone led to complete clearing of the bullous skin eruption and marked improvement of the patient's diarrhoea. Gastrointestinal disorders such as lymphocytic colitis have rarely been reported in patients with LAD. Whether the simultaneous occurrence of these two diseases is coincidental or due to related pathogenetic mechanisms remains to be seen.

Aged↗
PubMed1999

Role of ERCP and endoscopic sphincterotomy in acute pancreatitis.

When assessing the indications for interventional endoscopy, obstructive and non-obstructive causes of acute pancreatitis should be distinguished. In non-obstructive (e.g. alcoholic) pancreatitis, no data are available proving any benefit for endoscopic retrograde cholangiopancreatography (ERCP) and sphincterotomy. In obstructive (e.g. biliary) pancreatitis, the pathogenetic role of gallstones is controversial. The vast majority of gallstones initiating biliary pancreatitis pass spontaneously through the papilla of Vater into the duodenum without causing cholangitis or obstructive jaundice. Three prospective randomized published studies have attempted to answer the question of whether urgent removal of the stone improves the prognosis of patients suffering from acute pancreatitis. From these studies it can be concluded that the use of ERCP in acute biliary pancreatitis should depend on biliary symptoms: in cases of obstructive jaundice or cholangitis, bile duct stones should be removed as soon as possible; in patients without biliary complications, emergency ERCP is neither beneficial nor cost-effective; if retained stones (without biliary complications) are suspected, they can be removed electively.

Acute Disease↗
PubMed1999

Evidence for an anion exchange mechanism for uptake of conjugated bile acid from the rat jejunum.

Absorption of conjugated bile acids from the small intestine is very efficient. The mechanisms of jejunal absorption are not very well understood. The aim of this study was to clarify the mechanism of absorption of conjugated bile acid at the apical membrane of jejunal epithelial cells. Brush-border membrane vesicles from intestinal epithelial cells of the rat were prepared. Absorption of two taurine-conjugated bile acids that are representative of endogenous bile acids in many variate vertebrate species were studied. In ileal, but not jejunal brush-border membrane vesicles, transport of conjugated bile acids was cis-stimulated by sodium. Transport of conjugated bile acids was trans-stimulated by bicarbonate in the jejunum. Absorption of conjugated dihydroxy-bile acids was almost twice as fast as of trihydroxy-bile acids. Coincubation with other conjugated bile acids, bromosulfophthalein, and DIDS, as well as by incubation in the cold inhibited the transport rate effectively. Absorption of conjugated bile acids in the jejunum from the rat is driven by anion exchange and is most likely an antiport transport.

Absorption↗
PubMed1999

Crohn's disease mimicking sarcoidosis in bronchoalveolar lavage.

Granulomatous disorders like sarcoidosis or Crohn's disease are commonly associated with extrapulmonary or extraintestinal manifestations which occasionally may represent the only symptoms. We describe a 28-year-old female patient suffering from atypical erythema nodosum and arthritis. Although the chest x-ray was unremarkable bronchoalveolar lavage revealed lymphocytic alveolitis with an elevated CD4/CD8 ratio of 8 and 11.4 at repeated examinations suggesting a diagnosis of sarcoidosis. Further diagnostic workup included endoscopy of the bowel. The macroscopic aspect and histology of the terminal small bowel and colon ascendens indicated Crohn's disease. The patient recovered on steroids and sulfasalazine. Six months later she developed a perianal abscess for which she needed surgery supporting the diagnosis of Crohn's disease. This is the first case of a significantly (>6) elevated CD4/CD8 ratio in Crohn's disease previously regarded as highly specific for sarcoidosis.

Adult↗
PubMed1999

Association of lymphocytic colitis with linear IgA dermatosis.

The case of a 66-year-old female patient is presented, who suffered from chronic watery diarrhea. In addition, she developed linear IgA dermatosis after oral treatment of a presumed yeast infection with nystatin. To evaluate the reason for her diarrhea, colonoscopy was performed. The macroscopic aspect of the colon mucosa was described as normal with no specific alterations for chronic inflammatory bowel disease or for bacterial infections. In contrast, the histologic examination revealed the typical characteristics of lymphocytic colitis. This disease is thought to be caused by immunological reactions against as yet unknown luminal antigens. After treatment with steroids and dapsone the diarrhea as well as the skin disease disappeared. To our knowledge, the present report describes for the first time the association of linear IgA dermatosis with lymphocytic colitis after oral treatment with nystatin. A possible causative link between these two disease entities is discussed.

Administration, Oral↗
PubMed1998

Evaluation of a cacao drink as a simple oral stimulus to assess gallbladder contraction.

UNLABELLED: Gallbladder contractility plays an important role in the pathogenesis of gallstones and in the course of cholelithiasis. Furthermore, a functioning gallbladder is an important condition for performing a successful disolution of gallstones by bile acids. Therefore, a reliable simple physiological test is desired to assess gallbladder contractility. In ten volunteers gallbladder contraction was stimulated by 50 g chocolate, 330 ml cacao drink or in comparison by intramuscular injection of 0.3 microgram/kg ceruletide. Gallbladder volume was measured sonographically and CCK in serum was determined by radioimmunoassay (RIA) after 0, 15, 30 and 45 min. Additionally gallbladder contraction was determined in 20 patients with symptomatic gallstones using cacao drink on ceruletide. In health volunteers remaining gallbladder volume after 30 min was 28% +/- 5% using ceruletide and 37% +/- 7% using cacao. Stimulation by chocolate resulted in a remaining volume of 59% +/- 12% after 45 min only. Simultaneously to gallbladder contraction an increase of CCK in serum was registered. 30 min after cacao CCK had increased from 0.9 to 3.3 pmol/l. Using chocolate an increase of CCK amounted to 2.1 pmol/l after 45 min only. In patients with gallstones the positive predictive value of the cacao test for a functioning gallbladder was 91% and the negative predictive value was 78% in comparison to the unphysiologic stimulation by ceruletide injection. CONCLUSION: Cacao test but not chocolate is suitable and reliable to assess gallbladder contraction in patients with symptomatic gallstones.

Adult↗
PubMed1998

Endoscopic sphincterotomy for acute pancreatitis: arguments against.

ERCP and sphincterotomy (EPT) are well accepted as the procedure of choice for diagnostic and therapeutic purposes of extrahepatic biliary obstructions. In case of obstructive jaundice and biliary sepsis urgent sphincterotomy is the method of choice, also during acute pancreatitis. The question has been debated whether endoscopic sphincterotomy improves the prognosis of acute (e.g. biliary) pancreatitis itself. With regard to biliary problems different causes of pancreatitis should be distinguished: If the cause of pancreatitis is not obstructive like biliary pancreatitis but metabolic or toxic like alcoholic pancreatitis, no sphincterotomy is indicated. With regard to biliary pancreatitis three prospective randomised trials have been published. All agree to an urgent endoscopic treatment of biliary complications like obstructive jaundice or biliary sepsis during acute pancreatitis. Two of these studies did not find any benefit of interventional endoscopy concerning local or systemic complications of pancreatitis but observed a benefit concerning biliary complications. In one study including patients with biliary problems the complication rate but not mortality rate has been diminished by endoscopy in a subgroup of patients. It is concluded that urgency of ERCP in patients with acute pancreatitis depends on biliary symptoms. Sphincterotomy cannot be generally recommended for acute pancreatitis but only for biliary complications.

Acute Disease↗
PubMed1997

Early ERCP and papillotomy compared with conservative treatment for acute biliary pancreatitis. The German Study Group on Acute Biliary Pancreatitis.

BACKGROUND: The role of early endoscopic retrograde cholangiopancreatography (ERCP) and papillotomy in the treatment of patients who have acute biliary pancreatitis without obstructive jaundice is uncertain. METHODS: We conducted a prospective, multicenter study in which 126 patients were randomly assigned to early ERCP (within 72 hours after the onset of symptoms) and endoscopic papillotomy for the removal of stones in the common bile duct, when appropriate, and 112 patients were assigned to conservative treatment. In the conservative-treatment group, ERCP was performed within three weeks if signs of biliary obstruction or sepsis developed. Overall mortality, mortality due to pancreatitis, and complications were compared in the two groups. RESULTS: Early ERCP was successful in 121 of the 126 patients in the invasive-treatment group. Endoscopic papillotomy was performed to remove bile-duct stones in 58 patients; stones were successfully extracted in 57. ERCP was performed in 22 of the 112 patients in the conservative-treatment group; papillotomy for stone removal was successful in 13 patients. Fourteen patients in the invasive-treatment group and 7 in the conservative-treatment group died within three months (P=0.10); 10 patients in the invasive-treatment group and 4 in the conservative-treatment group died from acute biliary pancreatis (P=0.16). The overall rate of complications was similar in the two groups, but patients in the invasive-treatment group had more severe complications. Respiratory failure was more frequent in the invasive-treatment group, and jaundice was more frequent in the conservative-treatment group. CONCLUSIONS: In patients with acute biliary pancreatis but without obstructive jaundice, early ERCP and sphincterotomy were not beneficial.

Acute Disease↗
PubMed1996

Influence of density and viscosity of fluids on extracorporeal shock wave lithotripsy of gallstones in vitro.

BACKGROUND: It is hitherto still questionable which of the physical properties of the bile fluid influence the outcome of extracorporeal shock wave lithotripsy (ESWL). METHODS: In this study the influence of the density and viscosity of bile simulating fluid on ESWL was tested in vitro by applying CsCl solutions of densities 1.0, 1.3, 1. 5, 1.7 and 1.9 g/ml. Five almost identical "sister" stones from one patient were fragmented in these five fluids. The number of shock waves required for adequate fragmentation (fragments < 4 mm) was measured for comparison. This was repeated on a further seven patients (five "sister" stones per patient). Subsequently, the influence of the viscosity of the fluid on ESWL was tested using polyethylene glycol (PEG) solutions of the viscosities 1, 5, 17, 30 and 59 mPa.s. Analogous to the first part of this investigation, 40 gallstones from an additional eight patients (again five almost identical sister stones) were fragmented, registering the number of shock waves required for adequate fragmentation. RESULTS AND CONCLUSIONS: The density of the fluid did not reveal any monotone correlation to the number of shock waves required. In contrast to the density of the fluid there was a distinct correlation (r subsets = 0.84; p < 0.001) between its viscosity and the number of shock waves required. On average, the number of shock waves required in a fluid with a viscosity of 59 mPa . s must be more than three times that required in water, which has a viscosity of 1 mPa.s.

Cholelithiasis↗
PubMed1995

Urgent ERCP in all cases of acute biliary pancreatitis? A prospective randomized multicenter study.

In this prospective multicenter study, the effect of early ERCP within 72 hours after the beginning of symptoms in the treatment of acute biliary pancreatitis was investigated. 100 patients with acute biliary pancreatitis but without biliary sepsis or obstructive jaundice were randomized in this trial. 48 patients of the invasive group received urgent ERCP within 72 hours after the beginning of pain. 52 patients of the conventional group received ERCP only if biliary sepsis or obstructive jaundice occurred during the clinical course of the disease (which was the case in 10 patients). Sphincterotomy and stone extraction were undertaken if bile duct stones were identified during ERCP. In the invasive group, ERCP was successfully performed in 44 cases (92%). In 19 of these patients (43%), common bile duct stones were identified and a sphincterotomy was performed. The stones could be removed completely during the first ERCP examination in 16 cases. In the conventional group, 2 patients died from pancreatitis within 3 months, versus 4 patients in the invasive group. Cholecystitis occurred significantly more often in the conventional group (11 versus 4; odds ratio OR = 5.1), but no patient with cholecystitis or cholangitis died. Cholangitis (OR = 3.3) and sepsis (OR = 3.5) were slightly more frequent in the conventional group (not significant) while renal failure (OR = 0.5) and pulmonary failure (OR = 0.8) were slightly more frequent in the invasive group (not significant). Jaundice (6 patients) only occurred in the conventional group. In this multicenter study, it is concluded that early ERCP is not superior to conventional treatment in patients with acute biliary pancreatitis. On the other hand, patients with biliary complications (jaundice, sepsis, cholangitis) should receive urgent ERCP. However, most bile duct stones which initiate a pancreatitis pass spontaneously into the duodenum. The vast majority of patients suffering from biliary pancreatitis without biliary sepsis or obstructive jaundice require only elective ERCP when remaining bile duct stones are assumed. The lethality of biliary pancreatitis without initial biliary complications (sepsis, jaundice) tends to be elevated rather than diminished by emergency ERCP.

Acute Disease↗
PubMed1994

Extracorporeal shock wave lithotripsy of gallstones in different biles and water in vitro.

Twenty-four gallstones were fragmented by extracorporeal shock wave lithotripsy (ESWL) to compare the influence of three different biles (bovine bile, human bile, synthetic bile) and water on the rapidity of fragmentation. Four groups of comparable stones were used for lithotripsy in vitro. The stones were collected from 6 patients, four nearly identical 'sister' stones from each patient. The number of shock waves required for adequate fragmentation (fragments < or = 4 mm) was measured for comparison. Overall highly significant differences were found for the four different 'biles' with regard to the number of shock waves required for adequate fragmentation. Using synthetic bile, which was artificially composed according to a textbook on hepatology, significantly more shock waves were necessary for fragmentation compared to the use of water, bovine bile or human bile. On the other hand, no significant difference between water and human bile could be registered. We conclude that the number of shock waves required for adequate lithotripsy is influenced by the composition of bile in which the stone is fragmented. Possibly results of ESWL can be improved by manipulation of the bile.

Animals↗