Biomedical subjects

C Müller

Publications and source records attributed to C Müller.

At least 199 records · Page 11Linked to original sources

PubMed1999

[The diagnosis of acute aortic diseases with multiplanar-detector CT using the spiral technic].

UNLABELLED: Acute diseases of the central arteries require an immediate investigation. An efficient, fast and reliable diagnosis is necessary because of the high mortality, if the patient remains untreated. These requirements are perfectly fulfilled by the new CT-techniques. METHODS: Suspected aortic diseases were examined with a new multi-slice helical CT. The thoracic or the abdominal aorta as well as the entire vascular tree from the supra-aortic branches to the inguinal arteries were investigated with different CT protocols. The slice-thickness and the scan mode were changed while the total examination time was kept constant for the first two groups. In the third group a monophasic examination was compared to a biphasic one. RESULTS: In the diagnosis of acute aortic diseases multi-slice helical CT proved to be a fast and reliable method with all scan protocols. The objective measurements of contrast homogeneity and image quality were comparable in the first two groups. The monophasic contrast medium injection protocol was superior to the biphasic administration mode. CONCLUSIONS: Multi-slice helical CT appears to be a very effective approach for the diagnosis of acute aortic diseases and seems to be the new gold standard.

Acute Disease↗

PubMed1999

Kinetics and characteristics of an acute phase response following cardiac arrest.

OBJECTIVE: Inflammation and hypoxia are frequently associated, but their interaction is poorly understood. In vitro studies have shown that hypoxia stimulates the genes of acute phase proteins (APP) and cytokines known to induce APP. We decided to determine kinetics and potential determinants of an acute phase response after cardiac arrest and to assess whether isolated moderate hypoxia can induce APP in humans in vivo. DESIGN: Prospective, observational study in patients and human experiment. SETTING: Tertiary care university hospital. PATIENTS AND PARTICIPANTS: 22 patients after primarily successful cardiopulmonary resuscitation (CPR) and 7 healthy volunteers. INTERVENTIONS: None in patients; exposure of volunteers to simulated altitude (460 torr/6 h). RESULTS: Following CPR, type-1 APP (C-reactive protein, alpha 1-acidglycoprotein, serum amyloid A) and type-2 APP (haptoglobin, alpha 1-antitrypsin) increased consistently within 1-2 days and the 'negative' APP transferrin was downregulated. This APP response occurred irrespective of the cause of arrest, the estimated time of anoxia, clinical course or patient outcome and was not different in patients with and without infectious complications. Exposure of healthy volunteers to less severe but more prolonged hypoxia did not induce APP, although a time dependent increase of serum erythropoietin (EPO) was measurable under these conditions, indicating the activation of oxygen dependent gene expression. CONCLUSIONS: (i) A marked acute phase response occurs regularly after cardiac arrest, but within the complexity of this situation the severity of hypoxia is not a predominant determinant of this response. (ii) Despite in vitro evidence for similarities in the oxygen dependent regulation of APP and EPO production, the oxygen sensitivity of these proteins in vivo is different. (iii) Measurements of APP are not revealing regarding infectious complications in the early phase after CPR.

Acute-Phase Proteins↗

PubMed1999

The urinary ratio of 5-hydroxytryptophol to 5-hydroxyindole-3-acetic acid in surgical patients with chronic alcohol misuse.

The urinary ratio of 5-hydroxytryptophol to 5-hydroxyindole-3-acetic acid was reported to be elevated for a period of up to 22 h following acute alcohol ingestion. Therefore, the ratio could detect continuous alcohol consumption, in what was considered to be a high-risk surgical group, on the evening prior to surgery. The aim of this study was to determine the preoperative ratio of 5-hydroxytryptophol to 5-hydroxyindole-3-acetic acid in patients with continuous preoperative alcohol misuse. Forty-two patients participated in this institutionally approved study, once their written informed consent had been obtained. Chronic alcoholics were defined by meeting the criteria of the Diagnostic and Statistical Manual of Mental Disorders criteria and an ethanol consumption > or =60 g/day. The urine samples were taken preoperatively and determined by means of gas chromatography-mass spectrometry and high performance liquid chromatography. The urinary ratio of 5-hydroxytryptophol to 5-hydroxyindole-3-acetic acid was significantly increased in chronic alcoholics. The ICU stay of these patients was significantly prolonged due to an increased incidence of pneumonia and sepsis. Five chronic alcoholics died, whereas no deaths occurred in the nonalcoholic group (p = 0.05). As the measurement of the urinary ratio of 5-hydroxy-tryptophol to 5-hydroxyindole-3-acetic acid could detect alcohol consumption immediately prior to operation, this marker could assist the carbohydrate-deficient transferrin in screening for patients with high-level dependency; these patients were considered to be at a high risk of developing intercurrent complications.

Adult↗

PubMed1999

Use of failed-fertilized oocytes for diagnostic zona binding purposes after sperm binding improvement with a modified medium.

PURPOSE: Because the availability of prophase oocytes for zona binding testing is limited, we compared sperm binding to the zona of failed-fertilized intracytoplasmic sperm injection (ICSI) and in vitro fertilization (IVF) oocytes after incubation in a standard IVF medium and a specially composed binding improvement medium. METHODS: Semen samples from nine patients and nine fertile donors were separated in parallel by the standard swim-up method in both media. Subsequently, hemizona assays were performed with prophase, failed-fertilized ICSI and IVF oocytes. RESULTS: Sperm separation resulted in a significantly higher sperm count (P < 0.01) and progressive motility (P = 0.018) in binding improvement medium. Moreover, spermatozoa coincubated with hemizonae (prophase, failed-fertilized ICSI and IVF oocytes) in binding improvement medium bound significantly more to hemizonae than in the controls (P < 0.01). However, the hemizona index did not differ. CONCLUSIONS: Thus, the limited number of human zonae can be increased by the use of oocytes that failed to fertilize during ICSI or IVF. This will lead to a qualitative improvement of the diagnostic spectrum in male-factor infertility.

Adolescent↗

PubMed1999

Interim analysis of a randomized controlled trial of combination of ribavirin and high dose interferon-alpha in interferon nonresponders with chronic hepatitis C.

UNLABELLED: This trial investigated the efficacy of a combination of high-dose interferon-alpha (IFN-alpha) with ribavirin in IFN nonresponders. STUDY PROTOCOL: 304 patients with chronic hepatitis C were treated with 5 MU IFN-alpha2b (IntronA(R), Schering-Plough) per TIW for 3 months. Nonresponders (defined by HCV-RNA positivity in serum after the 3 months of therapy) were randomized either to continue with IFN (5 MU IFN per TIW followed by 10 MU per TIW for each 3 months) alone (group A) or in combination with ribavirin (1-1.2 g per day) (group B). ALT was measured in monthly intervals, HCV-RNA in 3 monthly intervals. Pretreatment characteristics of the randomized patients were as follows: group A, n = 76; m/f, 54/22; 16% cirrhosis, age, 45. 7 +/- 12 years; ALT (U per litre), 66 +/- 35; group B, n = 81; m/f, 57/24; 17% cirrhosis, age, 48.2 +/- 12; ALT, 71 +/- 40. After 9 months of treatment, nine (11.6%) and 27 (32.5%, P = 0.0066) patients were HCV-RNA negative and 51 and 39 were HCV-RNA positive, in groups A and B, respectively. There were 17 drop-outs in group A and 15 in group B. Six months after treatment only two patients in group A (2.5%) and five (6%, P = 0.06) in group B had normal ALT and no detectable HCV-RNA in serum. In addition to the well-known side-effects of IFN the mean haemoglobin concentration dropped by 2 g per litre in group B. These data indicate that a combination of high-dose IFN with ribavirin is effective in inducing a short-lasting complete response in one-third of IFN nonresponders. Prolonged treatment with IFN/ribavirin may be necessary to obtain a sustained response.

Adult↗

PubMed1999

Pathogenicity of GBV-C/HGV infection.

Extensive studies of GBV-C/HGV in acute and chronic hepatitis non-A-non-E have failed to provide hard evidence for a major role in this disease. Persistent GBV-C/HGV viraemia is in most cases associated with normal ALT levels, and only in a minority of patients are mild elevations of aminotransferases found. Its disease-inducing capacity is questionable and the findings accumulated so far are best explained by looking at GBV-C/HGV as a well-adapted, predominantly parenterally transmitted, persistent virus; it might be transmitted concomitantly with another, still unidentified hepatitis non-A-non-E virus. This does not exclude the possibility that GBV-C/HGV might, in some rare cases and under certain circumstances, induce a hepatitis-like illness as seen with other viruses such as EBV or CMV. GBV-C/HGV definitely plays a minor role only, if any, in post-transfusion and community-acquired hepatitis non-A-non-E.

Alanine Transaminase↗

PubMed1999

Secretion of human meprin from intestinal epithelial cells depends on differential expression of the alpha and beta subunits.

Human meprin (N-benzoyl-l-tyrosyl-p-aminobenzoic acid hydrolase, EC 3.4.24.18), an astacin-type metalloprotease, is expressed by intestinal epithelial cells as a dimeric protein complex of alpha and beta subunits. In transfected cells, intracellular proteolytic removal of the membrane anchor from the alpha subunit results in its secretion, while the beta subunit and alpha/beta heterodimers are retained at the cell membrane. We investigated the consequence of differential intracellular processing of alpha and beta subunits in the human small and large intestine using subunit-specific immunohistochemistry, in situ hybridization and biosynthetic studies in organ culture. In the ileum, both subunits localize to the brush-border membrane of villus enterocytes. In contrast, the beta subunit is not expressed in the colon, which leads to the secretion of the alpha subunit. We conclude that differential expression of meprin alpha and beta subunits is a unique means of targeting the proteolytic activity of the alpha subunit either to the brush-border membrane in the ileum or to the lumen in the colon, suggesting dual functions of cell-associated and luminal meprin. Meprin alpha and beta subunits are also coexpressed in distinct lamina propria leukocytes, suggesting an additional role for this protease in leukocyte function in the intestinal mucosa.

Colon↗

PubMed1999

Tacrolimus (FK506) as primary immunosuppressant after lung transplantation.

BACKGROUND: Our positive experience with tacrolimus (FK 506) in heart transplantation has led to our assessing the use of this medication as a primary immunosuppressant in lung transplantation. 62 of our patients after lung transplantation were included in this study. The first 34 patients were treated with cyclosporine A (CyA), the remaining 28 with tacrolimus. No meaningful differences were found in baseline characteristics. The actuarial one-year survival rate was 70.6% for the CyA group and 92.3% for the tacrolimus group. The number of acute rejection episodes per patient was 1.50 for the CyA group versus 1.18 for the tacrolimus group (p < 0.05). The incidence of infection and their spectrum were comparable in both groups. The most frequently reported adverse events were diabetes mellitus 57% (tacrolimus) vs 23% (CyA), and renal insufficiency (27% vs 15%). Tacrolimus seems to be a more potent immunosuppressant after lung transplantation than CyA; on the other hand, diabetes and nephrotoxicity were diagnosed more frequently using tacrolimus. Although our results are very promising, further follow-up on the incidence of obliterative bronchiolitis is warranted.

Actuarial Analysis↗

PubMed1999

Prevention of radiocontrast-media-induced nephropathy in patients with pre-existing renal insufficiency by hydration in combination with the adenosine antagonist theophylline.

BACKGROUND: Radiographic contrast media (CM) application causes a decline in renal function, especially in patients with pre-existing renal dysfunction. In addition to hydration, several vasodilating substances have been evaluated for their ability to prevent renal damage after CM application. In a prospective, double-blind, placebo-controlled study we investigated the effect of the oral administration of theophylline, an adenosine receptor antagonist, on changes in renal haemodynamics and tubular injury induced by CM in well-hydrated patients with mild-to-moderate renal insufficiency. METHODS: We studied 80 patients with pre-existing chronic renal insufficiency (creatinine > 1.5 mg/dl) who received more than 100 ml iopromide. Hydration (either oral or intravenous) started at least 24 h before and lasted until 24 h after CM application. In addition, patients were randomly assigned to receive either theophylline (810 mg daily) or placebo. Serum creatinine and creatinine clearance were measured before and for 3 days after CM application. Urine was collected to measure N-acetyl-beta-glucosaminidase (NAG) enzymuria for the same period. Sixty-four patients completed the entire study protocol (theophylline, n = 35 and placebo, n = 29). RESULTS: During the study period serum creatinine concentration and creatinine clearance did not change significantly in either group. Acute renal failure (increase of serum creatinine of at least 0.5 mg/dl) could be observed in two patients from the theophylline group (5.7%) and one from the placebo group (3.4%). The increase in NAG excretion reached statistical significance (P < 0.05) in the placebo group on days 2 and 3 after CM application. CONCLUSIONS: Our results indicate a role for adenosine in CM-induced tubulotoxicity. However, the glomerular filtration rate is preserved by hydration alone in these patients. The application of theophylline did not bring an additional benefit. The use of adenosine antagonists may be beneficial in patients where sufficient hydration may be impossible or in patients with a concomitant decrease in renal blood flow (e.g. congestive heart failure).

Acetylglucosaminidase↗

PubMed1999

Prognostic value of cardiac troponin T and I elevations in renal disease patients without acute coronary syndromes: a 9-month outcome analysis.

BACKGROUND: Moderate elevations of cardiac troponin (Tn) T, up to levels presumably diagnostic for minor myocardial damage, are suspected to be false positive in nearly 0.3 of end-stage renal disease (ESRD) patients undergoing haemodialysis (HD). It is not clear whether cardiac TnI is superior to TnT in those patients, if differences between ESRD and pre-ESRD occur, and what the prognostic meaning of these troponin elevations might be. SUBJECTS AND METHODS: We examined 40 chronic renaldisease patients [56.4 SD 13.9 years; 22 male, 18 female) without evidence of an acute coronary syndrome (ACS) for at least 28 days prior to the investigation. Cardiac status was determined by history, physical examination, ECG and echocardiography. Patients were divided into subgroups with HD (n = 20) and without HD (n = 20). Patients without HD had a mean creatinine clearance (CC) of 13.45 ml/min. Tn were measured by immunoassay techniques. TnT was compared to two different TnI tests (TnID, TnIB), CK/CKMB activity and myoglobin (MYO) concentrations. In all patients, a 9-month follow-up for acute myocardial infarction, re-hospitalization, and death was completed. RESULTS: None of the troponins significantly predicted patient outcome. Tn did not correlate with CC (r<0.6). Applying the lowest reported threshold values for all tests in the HD group, 0.3 patients were positive for TnT, 0.55 patients were positive for TnID, and 0.15 for TnIB. In the group without HD, 0.2 patients were positive for TnT and TnID and 0.1 for TnIB. CONCLUSIONS: Moderate elevations of cardiac troponins are common in clinically stable patients with renal disease and are neither diagnostic for an acute coronary syndrome nor predictive of outcome. It is concluded that increased troponins in asymptomatic renal patients are of questionable value for risk stratification, most probably due to unspecific elevations.

Adult↗

PubMed1999

Important role of nondiagnostic blood loss and blunted erythropoietic response in the anemia of medical intensive care patients.

OBJECTIVE: To determine incidence, severity, characteristics, and causes of anemia and transfusion requirements in medical intensive care patients. DESIGN AND SETTING: Open prospective clinical study in a 24-bed medical intensive care unit in a tertiary-care university hospital. PATIENTS: Patients (N = 96) treated in the intensive care unit for >3 days. INTERVENTIONS: None. MEASUREMENTS: Parameters of erythropoiesis and red blood cell metabolism, including hemoglobin, reticulocyte counts, serum iron, transferrin, ferritin, haptoglobin, vitamin B12, folic acid, and erythropoietin concentrations were determined serially. Diagnostic blood loss and red blood cell transfusions were recorded, and the total blood loss was estimated from changes in hemoglobin concentrations and the amount of hemoglobin transfused. MAIN RESULTS: The median hemoglobin concentration was 12.1 g/dL at admission and 11.2 g/dL at the end of the intensive care unit stay. A total of 74 patients (77%) suffered from anemia and received 257 red blood cell units, approximately half of which were given within the first 5 days. Three patients who received 19 red blood cell units were admitted with acute gastrointestinal bleeding, but in the remainder, a median total blood loss of 128 mL/d was not (n = 60) or not solely (n = 11) a result of overt bleeding. Diagnostic blood loss declined from a median of 41 mL on day 1 to <20 mL after 3 wks and contributed 17% (median) to total blood loss. Acute renal failure, fatal outcome, and simplified acute physiology score >38 on admission were associated with a 5.8-, 7.0-, and 2.8-fold increase in total blood loss. Reticulocyte counts and erythropoietin concentrations were inappropriately low for the degree of anemia, and plasma transferrin saturation was mostly <20%. CONCLUSIONS: Anemia is frequent and results in a high requirement for red blood cell transfusions in the medical intensive care setting. A major proportion of blood loss is not caused by overt bleeding or diagnostic blood sampling but, rather, may result from various other reasons, e.g., occult gastrointestinal bleeding and renal replacement therapy. The erythropoietic response to anemia is blunted, probably as a consequence of an inappropriate increase in erythropoietin production and diminished iron availability. (Crit Care Med 1999; 27:2630-2639)

APACHE↗

PubMed1999

Description of Pseudaminobacter gen. nov. with two new species, Pseudaminobacter salicylatoxidans sp. nov. and Pseudaminobacter defluvii sp. nov.

An aerobic bacterium, strain BN12T, which degrades substituted naphthalenesulfonates and substituted salicylates was isolated from a 6-aminonaphthalene-2-sulfonate-degrading microbial consortium originating from the River Elbe, Germany. Chemotaxonomic investigations of quinones, polyamines and polar lipids allowed allocation of this strain to the alpha-subclass of the Proteobacteria and revealed similarity to species of the genera Aminobacter, Chelatobacter and Mesorhizobium. This was confirmed by typing with 16S rRNA-targeted oligonucleotide probes and 16S rDNA sequencing and phylogenetic analysis, indicating that BN12T clusters most closely with a strain 'Thiobacillus' THI 051T and with the above genera but comprising a separate branch. DNA-DNA hybridizations demonstrated that strain BN12T is different from all species of Aminobacter currently described and recognized. The fatty acid patterns, substrate utilization profile and biochemical characteristics displayed no obvious similarity to the characteristics of Aminobacter and Chelatobacter species. 'Thiobacillus' THI 051T, however, revealed phenotypic similarities to BN12T. Furthermore, 16S rRNA sequences of Chelatobacter heintzii showed a high similarity to the 16S rRNA sequences of all currently recognized Aminobacter species. On the basis of these and previously published results, the new genus Pseudaminobacter is proposed, harbouring the two new species Pseudaminobacter salicylatoxidans sp. nov. and Pseudaminobacter defluvii sp. nov. The type strains are BN12T (= DSM 6986T) and THI 051T (= IFO 14570T), respectively.

Bacterial Typing Techniques↗

PubMed1999

Large-scale clustering of cDNA-fingerprinting data.

Clustering is one of the main mathematical challenges in large-scale gene expression analysis. We describe a clustering procedure based on a sequential k-means algorithm with additional refinements that is able to handle high-throughput data in the order of hundreds of thousands of data items measured on hundreds of variables. The practical motivation for our algorithm is oligonucleotide fingerprinting-a method for simultaneous determination of expression level for every active gene of a specific tissue-although the algorithm can be applied as well to other large-scale projects like EST clustering and qualitative clustering of DNA-chip data. As a pairwise similarity measure between two p-dimensional data points, x and y, we introduce mutual information that can be interpreted as the amount of information about x in y, and vice versa. We show that for our purposes this measure is superior to commonly used metric distances, for example, Euclidean distance. We also introduce a modified version of mutual information as a novel method for validating clustering results when the true clustering is known. The performance of our algorithm with respect to experimental noise is shown by extensive simulation studies. The algorithm is tested on a subset of 2029 cDNA clones coming from 15 different genes from a cDNA library derived from human dendritic cells. Furthermore, the clustering of these 2029 cDNA clones is demonstrated when the entire set of 76,032 cDNA clones is processed.

Algorithms↗

PubMed1999

Prevalence of GBV-C/HGV-RNA, virus genotypes, and anti-E2 antibodies in autoimmune hepatitis.

OBJECTIVE: We investigated the prevalence of hepatitis G-RNA (GBV-C/HGV-RNA), a recently cloned new flavivirus, and of antibodies to the envelope 2 antigen (anti-E2), a marker of past infection, in patients with autoimmune hepatitis, and compared it with the prevalence in patients with chronic viral hepatitis and healthy control individuals. METHODS: Sera of 63 patients with autoimmune hepatitis were studied for the presence of GBV-C/HGV-RNA by reverse-transcription polymerase chain reaction and for anti-E2 by enzyme-linked immunosorbent assay. GBV-C/HGV genotypes were determined by genome sequencing. RESULTS: Patients with autoimmune hepatitis had a similar high prevalence of GBV-C/HGV-RNA and anti-E2 antibodies as patients with chronic viral hepatitis B or C. GBV-C/HGV-RNA was found significantly more often in patients with autoimmune hepatitis (11%, p = 0.045), hepatitis B (16%, p = 0.004), or hepatitis C (21%, p = 0.001) than in healthy controls (2%). The prevalence of anti-E2 antibodies in patients with autoimmune hepatitis was not different from healthy controls (17% vs 13%, NS). The various subtypes of autoimmune hepatitis had similar prevalence rates of GBV-C/HGV-RNA as patients with liver-kidney microsomal antibody-positive hepatitis C. All of our anti-E2+ (GBV-C/HGV-RNA-) patients were positive for anti-smooth-muscle antibody, whereas only 29% of GBV-C/HGV-RNA+ (anti-E2-) patients were positive (p = 0.025). All seven of the GBV-C/HGV-RNA+ patients with autoimmune hepatitis had genotype 2a, which is also the most prevalent genotype in our region. CONCLUSION: The prevalence of GBV-C/HGV-RNA is significantly increased in patients with autoimmune hepatitis, compared with healthy controls, and is similar to the increased prevalence seen in chronic hepatitis B or C patients. Anti-E2 positivity was associated with antibodies against smooth-muscle antigen in all cases. All GBV-C/HGV+ autoimmune hepatitis patients were infected with genotype 2a.

Adult↗

PubMed1999

Effects of salicylic acid derivatives on red blood cell membranes.

Salicylamide, sodium salicylate and acetylsalicylic acid are salicylic acid derivates. They differ in their substitution on the benzene ring and may have different effects on membranes. Red blood cells were used as a prototypical cellular system regarding drug mediated plasma bilayer effects. Established photometric methods sensing tiny changes of red blood cell morphology at rest (red blood cell shape) and at very low shear forces (red blood cell stiffness, red blood cell relaxation time) were applied. The derivative induced effects were detected in a time- and dose-dependent manner. Salicylamide induced a most pronounced echinocytic shape at 5 mM. The shape effect was smaller above as well as below 5 mM. Sodium salicylate induced echinocytes with increasing concentrations showing a saturation above 10 mM. In contrast, the shape was not affected by acetylsalicylic acid. All shape changes occurred within 2 min, and were reversible. The above tendencies were in parallel to a slight red blood cell stiffening. The relaxation time continuously increased with increasing concentrations in both salicylamide and sodium salicylate, with salicylamide always acting stronger. Acetylsalicylic acid again showed no effect. We hypothesize that the observed effects of sodium salicylate and salicylamide are due to their phenolic character mediating a molecular hydrophobicity. According to the bilayer couple hypothesis this would lead to an insertion into the red blood cells outer plasma bilayer leaflet. The extension induced here would cause a positive membrane bending leading to echinocytic shapes and the observed loss of red blood cell fluidity. In contrast, the hydrophilic aspirin would penetrate and thus not affect the red blood cell plasma membrane.

Aspirin↗

PubMed1999

Catalytic properties of the 3-chlorocatechol-oxidizing 2, 3-dihydroxybiphenyl 1,2-dioxygenase from Sphingomonas sp. strain BN6.

The 2,3-dihydroxybiphenyl dioxygenase from Sphingomonas sp. strain BN6 (BphC1-BN6) differs from most other extradiol dioxygenases by its ability to oxidize 3-chlorocatechol to 3-chloro-2-hydroxymuconic semialdehyde by a distal cleavage mechanism. The turnover of different substrates and the effects of various inhibitors on BphC1-BN6 were compared with those of another 2,3-dihydroxybiphenyl dioxygenase from the same strain (BphC2-BN6) as well as with those of the archetypical catechol 2,3-dioxygenase (C23O-mt2) encoded by the TOL plasmid. Cell extracts containing C23O-mt2 or BphC2-BN6 converted the relevant substrates with an almost constant rate for at least 10 min, whereas BphC1-BN6 was inactivated significantly within the first minutes during the turnover of all substrates tested. Furthermore, BphC1-BN6 was much more sensitive than the other two enzymes to inactivation by the Fe(II) ion-chelating compound o-phenanthroline. The reason for inactivation of BphC1-BN6 appeared to be the loss of the weakly bound ferrous ion, which is the cofactor in the catalytic center. A mutant enzyme of BphC1-BN6 constructed by site-directed mutagenesis showed a higher stability to inactivation by o-phenanthroline and an increased catalytic efficiency for the conversion of 2,3-dihydroxybiphenyl and 3-methylcatechol but was still inactivated during substrate oxidation.

Catalytic Domain↗

PubMed1999

Functions of cyclin A1 in the cell cycle and its interactions with transcription factor E2F-1 and the Rb family of proteins.

Human cyclin A1, a newly discovered cyclin, is expressed in testis and is thought to function in the meiotic cell cycle. Here, we show that the expression of human cyclin A1 and cyclin A1-associated kinase activities was regulated during the mitotic cell cycle. In the osteosarcoma cell line MG63, cyclin A1 mRNA and protein were present at very low levels in cells at the G0 phase. They increased during the progression of the cell cycle and reached the highest levels in the S and G2/M phases. Furthermore, the cyclin A1-associated histone H1 kinase activity peaked at the G2/M phase. We report that cyclin A1 could bind to important cell cycle regulators: the Rb family of proteins, the transcription factor E2F-1, and the p21 family of proteins. The in vitro interaction of cyclin A1 with E2F-1 was greatly enhanced when cyclin A1 was complexed with CDK2. Associations of cyclin A1 with Rb and E2F-1 were observed in vivo in several cell lines. When cyclin A1 was coexpressed with CDK2 in sf9 insect cells, the CDK2-cyclin A1 complex had kinase activities for histone H1, E2F-1, and the Rb family of proteins. Our results suggest that the Rb family of proteins and E2F-1 may be important targets for phosphorylation by the cyclin A1-associated kinase. Cyclin A1 may function in the mitotic cell cycle in certain cells.

Animals↗

PubMed1999

Impacted papilla minor stone in pancreas divisum causing severe acute pancreatitis: a case for early ERCP in acute pancreatitis of unknown origin.

This is the first description of severe acute pancreatitis in pancreas divisum caused by a solitary stone impacted in the minor papilla. Recovery was rapid after diagnostic endoscopic retrograde cholangiopancreaticography (ERCP) and endoscopic stone removal. Since other etiological factors accounting for the acute pancreatitis were carefully excluded, it seems that obstruction of the minor papilla by a solitary pancreatic concrement was the most likely cause of acute pancreatitis. This case report demonstrates the diagnostic importance of early ERCP in cases of etiologically unexplained acute pancreatitis.

Acute Disease↗