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Biomedical subjects

R Baumann

Publications and source records attributed to R Baumann.

At least 37 records · Page 2Linked to original sources
PubMed2000

Antioxidant and immune status in active Crohn's disease. A possible relationship.

BACKGROUND AND AIMS: As reactive oxygen has been demonstrated to participate in immune genes transcription, the aim of this study was to examine the relationship between systemic concentrations of several antioxidants and markers of inflammatory and immune activation in patients with Crohn's disease (CD). METHODS: In 26 CD patients and 15 controls we compared plasma selenium and zinc concentrations, erythrocyte glutathione peroxidase (GSHPx) and superoxide dismutase activities, as well as erythrocyte sedimentation rate (ESR), C-reactive protein, tumor necrosis factor-alpha, interleukin-6, blood neopterin and soluble receptors of interleukin-2 (sIL-2R), and examined the link between these parameters. RESULTS: Selenium concentration and GSHPx activity were decreased in CD patients (54.5 +/- 3.2 vs 79 &plusmn 2.2 microg/l, P<< 0.05; 28 +/- 1.6 vs 38 +/- 2.6 IU/g Hb, P<< 0.05) and positively correlated to each other's (r= 0.59, P<< 0.01). TNF-alpha was significantly increased in patients (18 +/- 2.6 vs 5 +/- 0.6 pg/ml;P<< 0.001), negatively correlated to GSHPx activity (r= -0.56, P<< 0.05) and selenium concentration (r= -0.72, P<< 0.001), and positively to neopterin and sIL-2R concentrations. Selenium showed negative correlation with sIL-2R (r= -0.83, P<< 0.0001) and ESR. CONCLUSIONS: In CD patients low selenium concentration may participate in reduced GSHPx activity facilitating inflammatory and immune activation. In these patients, selenium monitoring and, if needed, supplementation may be of therapeutical interest.

Adult↗
PubMed2000

Factors associated to hypermanganesemia in patients receiving home parenteral nutrition.

BACKGROUND: Home parenteral nutrition (HPN) patients often present hypermanganesamia. AIM: To examine which factors may be associated to hypermanganesemia in HPN patients. METHODS: Plasma manganese (Mn), liver function tests, C-reactive protein concentrations, erythrocyte sedimentation rate (ESR), tumor necrosis factor-alpha (TNF- alpha), interleukin-6, soluble receptors of interleukin-2, and blood neopterin concentrations were determined in 21 HPN patients and 10 healthy controls. Brain magnetic resonance imaging (MRI) and careful neurologic clinical examination were performed in 11 patients. RESULTS: Mn concentration was higher in HPN patients than controls (1.96+/-1.1 vs 0.81+/- 0.4 microg/L;P<0.001) and positively correlated to the amount of parenteral nutrition (PN) supply, transaminases and alkaline phosphatase (r=0.53, P<0.0001) concentrations, as well as to ESR (r=0.61, P<0.0001), TNF- alpha and blood neopterin. The amount of calories provided by PN was positively correlated to inflammatory markers and liver parameters. All patients investigated by MRI showed hyperintense basal ganglia on T1-weighted images suggesting brain Mn deposition. Only one had slight clinical extrapyramidal symptoms. CONCLUSION: In HPN patients, sustained inflammation may facilitate hypermanganesemia through 1. cholestatic liver disease and thereby decreased Mn biliary excretion, 2. high nutritional requirements (responsible for increased Mn supply), and/or 3. modified Mn metabolism or body distribution. Neurologic complications appeared marginal whereas Mn brain deposition seems frequent.

Adult↗
PubMed2000

Vitamins and trace elements in home parenteral nutrition patients.

AIMS: to study the micronutrient status in home parenteral nutrition (HPN) patients and its relationship to inflammatory markers, and clinical outcome. METHODS: Vitamins (A, 25OH D3, E, B12), serum folic acid, as well as trace elements (selenium, zinc, copper, iron and manganese) were measured in 22 adult HPN patients and 14 controls. They were compared to serum malondialdehyde (MDA) concentration (as a marker of lipid peroxidation), erythrocyte superoxide dismutase (SOD) and gluthatione peroxidase (GSHPx), inflammatory markers, and clinical outcome. RESULTS: In HPN patients MDA concentration was increased whereas vitamin E concentrations were decreased, and significantly negatively correlated to MDA. Erythrocyte GSHPx and plasma selenium were decreased in the patients and positively correlated to each other. By contrast, manganese concentration was significantly increased in HPN patients and correlated to inflammatory markers. CONCLUSIONS: Adult HPN patients showed increased lipid peroxidation. This seems principally the result of low vitamin E status. In addition, these patients presented often a decrease in plasma selenium responsible for low GSHPx activity. These combined antioxidant system deficiencies contribute probably to peroxidative damage in HPN patients. Increased manganese concentrations, in view of their potential neurotoxicity have to be closely surveyed. In HPN patients micronutrient status needs regular monitoring in regard to the possibility of vitamin and/or trace element abnormalities.

Adult↗
PubMed1999

Ontogeny of catecholamine and adenosine receptor-mediated cAMP signaling of embryonic red blood cells: role of cGMP-inhibited phosphodiesterase 3 and hemoglobin.

We have previously shown that the cAMP signaling pathway controls major aspects of embryonic red blood cell (RBC) function in avian embryos (Glombitza et al, Am J Physiol 271:R973, 1996; and Dragon et al, Am J Physiol 271:R982, 1996) that are important for adaptation of the RBC gas transport properties to the progressive hypercapnia and hypoxia of later stages of avian embryonic development. Data about the ontogeny of receptor-mediated cAMP signaling are lacking. We have analyzed the response of primitive and definitive chick embryo RBC harvested from day 3 to 18 of development towards forskolin, beta-adrenergic, and A2 receptor agonists. The results show a strong response of immature definitive and primitive RBC to adenosine A2 and beta-adrenergic receptor agonists, which is drastically reduced in the last stage of development, coincident with the appearance of mature, transcriptionally inactive RBC. Modulation of cGMP-inhibited phosphodiesterase 3 (PDE3) has a controlling influence on cAMP accumulation in definitive RBC. Under physiological conditions, PDE3 is inhibited due to activation of soluble guanylyl cyclase (sGC). Inhibition of sGC with the specific inhibitor ODQ decreases receptor-mediated stimulation of cAMP production; this effect is reversed by the PDE3 inhibitor milrinone. sGC is acitivated by nitric oxide (NO), but we found no evidence for production of NO by erythrocyte NO-synthase. However, embryonic hemoglobin releases NO in an oxygen-linked manner that may activate guanylyl cyclase.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1999

Craniospinal axis irradiation in children. Treatment in supine position including field verification as a prerequisite for anesthesia without intubation.

PURPOSE: For craniospinal axis irradiation in young children sometimes anesthesia is required. In order to minimize risks from the anesthesist's point of view supine position would be preferable to standard prone position. In case of irradiation in supine position verification of the 3-field junction in the cervical region causes problems, because there is no direct visual control. For such situations the clinical application of a new technique is presented. PATIENTS AND METHODS: For treatment planning a modern 3D planning system was necessary. Patient's positioning was done by using a vacuum-form body immobilizer and an integrated head mask. Radiation fields were placed only by table movements being calculated by the planning system in relation to a reference point at the patient's surface. In addition to common verification films specially prepared small films were used for the 3-field junction in the cervical region. These films were placed close to the patient for the whole time of each radiation session being exposed by every radiation field. RESULTS: Two children (age 3 and 5 years, respectively) were irradiated as described. Twenty-eight of those specially prepared films were exposed. Two films (7%) had to be excluded because of inadequate exposure. An overlap of radiation fields was seen on 1 of the 26 remaining films (4%), whereas an unacceptable gap was not found. Acute skin reactions were comparable to those observed in patients being irradiated in standard prone position. CONCLUSION: The presented technique for craniospinal axis irradiation in supine position including field verification was not only precise and reproducable, but also comfortable and safe for the patient. We suggest it as a new option for craniospinal axis irradiation in children.

Anesthesia, General↗
PubMed1999

Management of common bile duct stones in a single operation combining laparoscopic cholecystectomy and perioperative endoscopic sphincterotomy.

BACKGROUND: Laparoscopic cholecystectomy (LC) has become the reference treatment for biliary lithiasis, but the management strategy for common bile duct stones (CBDS) remains a subject of controversy in the absence of an established consensus. While conventional surgery remains the reference treatment for CBDS, minimally invasive techniques are becoming more and more popular. These methods consist of the extraction of the common bile duct stones either exclusively by laparoscopy or by sequential treatment with endoscopic sphincterotomy (ES) followed by LC. The aim of this study was to evaluate the treatment of CBDS in a one-stage operation by laparoscopic cholecystectomy (LC) and perioperative endoscopic sphincterotomy. PATIENTS AND METHODS: Between January 1994 and March 1998, 44 patients, 20 male and 24 female, (sex ratio 1.2) with a median age of 57 years (range 28-84 years) were treated for suspected or confirmed CBDS. The CBDS were uncomplicated in 39 cases (88%) and associated with a complication in 5 cases (12%), namely, cholangitis (2 cases) or acute pancreatitis (3 cases). The perioperative ES was performed immediately after the LC during the same operative time, with perioperative cholangiography being systematically performed (1 failure). In 6 cases, a transcystic drain was left in place (to ensure complete evacuation of the CBDS postoperatively) when there were more than three stones and/or when they were larger than 6 mm. The patient was positioned in the left lateral position in order to perform the ES. RESULTS: Mean operative time for LC was 60 min, range 40-90 min. The general anesthesia was prolonged by 40 min in order to perform an ES (range 30-60 min). The perioperative ES was unsuccessful in one case (2%), due to the impossibility of catheterizing the papilla, the preoperative MR cholangiogram being normal. Immediate clearance of the CBD was achieved in 95% of the cases (42 p). In 2 cases, residual stone was found in the sixth day after cholangiography and was spontaneously evacuated as shown by 21st-day control. There was no mortality or postoperative complications. The duration of the postoperative hospitalization was 4.6 days (range 3-6). CONCLUSIONS: We believe that LC combined with perioperative ES is a quick, reliable, and safe technique for the treatment of CBDS during a single operative procedure, although this approach is limited by the proximity and availability of an endoscopic team.

Adult↗
PubMed1999

Frequent factor II G20210A mutation in idiopathic portal vein thrombosis.

BACKGROUND & AIMS: Despite extensive investigations of portal vein thrombosis, no underlying cause is identifiable in up to 30% of patients. A recently described mutation of the prothrombin gene at nucleotide position 20210 is associated with history of venous thrombosis and was assessed in this study. METHODS: We compared the frequency of factor II G20210A and factor V G1691A (factor V Leiden) mutations in 10 patients with idiopathic portal vein thrombosis, 10 patients with nonidiopathic portal vein thrombosis, 60 patients with deep vein thrombosis of the legs, and 42 control subjects. RESULTS: The frequency of factor II G20210A mutation was increased in patients with idiopathic portal vein thrombosis (40.0%; confidence interval, 3.1%-76.9%) compared with controls (4.8%; confidence interval, 0%-11.5%) or patients with nonidiopathic portal vein thrombosis or deep vein thrombosis (P = 0.0001). In contrast, the frequency of the factor V G1691A mutation was similar in subjects with portal vein thrombosis and in controls but was increased in patients with deep vein thrombosis (P = 0.0001). CONCLUSIONS: The factor II G20210A mutation is frequent in patients with idiopathic portal vein thrombosis and should therefore be assessed under this circumstance.

Adult↗
PubMed1999

Metachromatic activity of beta-cyclodextrin sulfates as heparin mimics.

Heparin is a versatile biologically active substance which has been reported to have an inhibitory effect on angiogenesis if administered together with hydrocortisone. Since very little is known about the mechanism of this activity, beta-cyclodextrin sulfates were prepared to mimic heparin. The sulfate groups were introduced into beta-cyclodextrin regioselectively using protecting groups. The obtained polyanions were tested for their complex binding properties by mixing them with cationic dyes and measuring the metachromatic response which proved to be a very useful tool to evaluate the biological activity of these compounds. The results reveal that the activity depends largely upon the charge density at the surface of the beta-cyclodextrin sulfates: a large number of sulfate groups or anionic groups relatively close to each other display high activity, whereas molecules with fewer sulfate groups or with them more distant from each other exhibit smaller activities.

Cyclodextrins↗
PubMed1999

Nitric oxide end products in patients hospitalized for diarrhoea.

OBJECTIVE: Increased nitric oxide (NO) has been demonstrated in inflammatory bowel diseases (IBD). Plasma and urinary nitrite and nitrate are usually considered to reflect global NO generation. Recently it has been suggested that plasma nitrate may be a discriminant indicator between infectious enterocolitis (IC) and IBD. To investigate this hypothesis we compared plasma and 24 h urinary nitrite and nitrate in 13 healthy controls, 44 patients with IBD [Crohn's disease (CD) n = 30; ulcerative colitis (UC) n = 14], 16 patients presenting with IC and seven chronic radiation enterocolitis (RE) patients. RESULTS: Despite a trend towards higher plasma nitrate in IC (54.6+/-11.4 micromol/l) than in the other groups (CD: 38.4+/-4.8, UC: 34.8+/-8.4, RE: 34.7+/-7.5, controls: 31.1+/-5.2), this difference was not statistically significant. Urinary nitrate was higher in IBD, IC and RE than in controls, with no difference between these groups. Nitrite concentrations were not different. Nitrate levels were positively correlated with blood and 24 h urinary neopterin (e.g. plasma nitrate and blood neopterin: r = 0.54, P<0.0001), and in some cases, to C-reactive protein. CONCLUSIONS: High nitrate (in our case only urinary nitrate) appears to be secondary to the magnitude of the inflammation rather than the aetiology of the diarrhoea. It should therefore more likely be considered as a marker of the severity of the inflammatory response rather than used as a discriminant indicator between IC and IBD patients.

Case-Control Studies↗
PubMed1999

Home parenteral nutrition: clinical and laboratory analysis of initial experience (1994-1997). Implications for patient management.

UNLABELLED: BACKGROUND/AIM AND METHOD: Severe malabsorption often necessitates prolonged parenteral nutrition. Home parenteral nutrition (HPN) offers the opportunity for treatment at home. We report clinical and laboratory data of initial 27 HPN patients of one center since its opening in 1994. RESULTS: Clinical and biological markers of nutritional status were normalized and well maintained in most patients. Except for vitamin E and selenium (lower in HPN patients), the other vitamin and micronutrient levels were normal. There was no obvious essential fatty acid deficiency. Cholestasis was usual, but only 1 patient had a severe hepatic disease. Catheter infection occurred 18 times in 13 patients, but the frequency decreased with time (from 4.2 to 1.7 infections/1,000 days on HPN). No patient died from HPN complications. Social rehabilitation and, in some patients, full professional rehabilitation were constant. CONCLUSIONS: These data confirm that HPN performed in centers with expertise allowed patients to overcome gut failure and to recover subnormal or normal nutritional status. Satisfactory social rehabilitation was obtained in all patients. HPN complications were rarely life-threatening, and their frequency decreased with experience.

Aged↗
PubMed1999

Management of common bile duct stones by laparoscopic cholecystectomy and endoscopic sphincterotomy: pre-, per- or postoperative sphincterotomy?

BACKGROUND/AIMS: The aim of this study was to evaluate the treatment of common bile duct stones (CBDS) by endoscopic sphincterotomy (ES) and laparoscopic cholecystectomy (LC), ES being performed either pre-, per- or postoperatively. METHODS: Between January 1990 and June 1997, 386 patients with a median age of 60 (range 18-92) years were treated for suspected or confirmed CBDS. The CBDS were uncomplicated in 264 cases (70%) but associated with a complication in 122 cases (30%), namely, cholangitis (69 cases) or acute pancreatitis (53 cases). ES combined with LC was carried out in 233 cases (60%): ES was preoperative (sequential treatment in two stages) in 197 cases (51%); peroperative in 30 cases (7%), or postoperative in 6 cases (2%). Laparoscopic extraction was performed in 58 cases (15%) and conventional surgery in 82 cases (21%). RESULTS: With respect to sequential treatment, endoscopic retrograde cholangiography showed the presence of CBDS in 117 cases (60%) and preoperative ES allowed the release of the CBDS in 82% of these cases. The complication rate of sequential treatment was 8% (15 cases) after ES and 7% (13 cases) after LC, with 1 death (0.5%). A peroperative ES performed after LC enabled evacuation of the CBDS in 28 cases (93%) without any complications or mortality. Postoperative ES was successful in 100% of cases with residual lithiasis in 16% (1 case) and a complication rate of 16% (1 case). CONCLUSION: Along with conventional surgery and laparoscopic extraction, ES combined with LC represents an effective alternative in the management of CBDS. Since it can be performed peroperatively, it allows a one-stage, minimally invasive treatment of most uncomplicated CBDS.

Adult↗
PubMed1999

Effect of high altitude and in vivo adenosine/(&bgr;)-adrenergic receptor blockade on ATP and 2,3BPG concentrations in red blood cells of avian embryos

In chick embryos, developmental changes of the blood oxygen tension control hemoglobin (Hb) oxygen affinity via modulation of ATP and 2, 3BPG concentrations in red blood cells. Hypoxia, which is a normal developmental condition for late chick embryos, causes a decrease of the red cell ATP concentration (and increase of red cell oxygen affinity) as well as activation of 2,3BPG synthesis via cyclic AMP-dependent signaling. Adenosine and catecholamines have been implicated as signaling substances in these red cell responses. To assess the extent to which adenosine and catecholamines are involved in vivo in the control of red cell ATP/2,3BPG concentrations, day 13 chick embryos were treated for 24 h with adenosine A(2) and/or (&bgr;)-adrenergic receptor blockers and red cell ATP and 2,3BPG levels were determined. The data suggest that adaptive effects later in development in chick embryos induced by adenosine and catecholamines are vital. We have also tested whether avian embryos of the free-living, high-altitude, native white-tailed ptarmigan (Lagopus leucurus) alter their organic phosphate pattern in red cells in response to incubation at different altitudes. Embryos incubated at 3600-4100 m decrease their red cell ATP concentration much more rapidly than embryos of the same clutch incubated at 1600 m. From these data it can be inferred that the oxygen affinity of high altitude embryos will be adjusted to the altitude at which the eggs are incubated.

Journal Article↗
PubMed1999

The influence of ionizing radiation on the CLARION 1.2 cochlear implant during radiation therapy.

OBJECTIVE: This study aimed to determine the maximum dose of radiation the CLARION 1.2 cochlear implant can withstand safely. INTRODUCTION: Cochlear implants restore functional hearing to patients with sensorineural deafness. Because some patients may need radiation therapy, it is important to investigate the influence of ionizing radiation on cochlear implant function. METHODS: This study tested the function of four CLARION 1.2 implants (Advanced Bionics, Sylmar, CA, U.S.A.) after varying radiation treatments with gamma rays. The first implant received a cumulative dosage of 69 Gy over nine treatments (single doses between 0.1-30 Gy). The second was irradiated with a total of 90 Gy, receiving three treatments of 30 Gy each. The third and fourth received doses more typical of patient therapy (i.e., 2 Gy) approximately 30 times, for a cumulative dosage of approximately 60 Gy. Implant function was tested after every treatment; the CLARION implant incorporates a back-telemetry system, allowing impedance and current output testing. RESULTS: Despite the type of treatment, the results were quite consistent: difficulties in function occurred when the cumulative dosage inside the implant was approximately 60 Gy. The first implant recovered completely and the second recovered partially. DISCUSSION: The CLARION 1.2 cochlear implant seems to safely withstand approximately 60 Gy of radiation before experiencing functional difficulties. In a clinical situation, the implant would not likely be in the target volume irradiated, and thus the patient's therapeutic cumulative dosage might be higher.

Cochlear Implants↗
PubMed1998

Adenosine 3':5'-cyclic monophosphate (cAMP)-inducible pyrimidine 5'-nucleotidase and pyrimidine nucleotide metabolism of chick embryonic erythrocytes.

Terminally differentiating erythrocytes degrade most of their RNA with subsequent release of mononucleotides. Pyrimidine mononucleotides are preferentially cleaved by an erythrocyte-specific pyrimidine 5'-nucleotidase; deficiency of this enzyme causes hemolytic anemia in humans. Details of the regulation of its activity during erythroid differentiation are unknown. The present study arose from the observation that the immature red blood cells (RBCs) of mid-term chick embryos contain high concentrations of uridine 5'-triphosphate (UTP) (5 to 6 mmol/L), which decline rapidly from days 13 to 14 onward. We analyzed two key enzymes of RBC pyrimidine nucleotide metabolism: pyrimidine nucleoside phosphorylase (PNP) and pyrimidine 5'-nucleotidase (P-5'-N), to evaluate if changes of enzyme activity during embryonic development are correlated with changes of RBC UTP. Secondly, we tested if these enzymes are under hormonal control. The results show that embryonic RBCs contain only minimal activity of PNP. In contrast, P-5'-N increases from day 13 on, suggesting that the enzyme is a limiting factor in UTP degradation. Activation of beta-adrenergic and A2A-adenosine receptors causes transcription-dependent de novo synthesis of P-5'-N. Because beta-adrenergic and adenosine receptors are also found on adult erythroid cells, P-5'-N might be an enzyme of differentiating RBCs whose expression is in part controlled by adenosine 3':5'-cyclic monophosphate (cAMP).

5'-Nucleotidase↗
PubMed1998

High signal in the adenohypophysis on T1-weighted images presumably due to manganese deposits in patients on long-term parenteral nutrition.

Hypermanganesaemia is reported in patients on long-term parenteral nutrition. Deposition of manganese, giving high signal on T1-weighted images, may involve the basal ganglia. MRI in nine patients (mean age 51 years, range 31-75 years) on long-term parenteral nutrition (mean duration 30 months, range 6-126 months), demonstrated high signal in the anterior pituitary gland on T1-weighted sagittal and coronal images. The gland appeared normal on T2-weighted images. Signal intensity in the basal ganglia on T1-weighted images was increased in all patients. Endocrine assessment showed no significant abnormality. Neurological examination showed a mild parkinsonian movement disorder in one patient. Hypermanganaesemia was present in all nine (1.3-2.8 micromol/l, mean 1.87 micromol/l). The high signal in the anterior pituitary gland was probably related to deposition of paramagnetic substances, especially manganese.

Adult↗
PubMed1998

The position of the ZEBRA activation domain does not influence its biological activity.

Epstein-Barr virus (EBV) is a human herpesvirus which latently infects B lymphocytes. EBV encodes a unique transcriptional activator, known as ZEBRA, which can disrupt viral latency in B cells and induce lytic viral replication. Furthermore, ZEBRA has been shown to bind at the EBV origin of lytic replication, and is necessary for viral DNA replication to occur. Previously we demonstrated that heterologous activation domains can fully substitute for the ZEBRA activation domain. Here we extend those results by showing that the position of the ZEBRA activation domain or a heterologous replacement domain does not influence its ability to function in the disruption of EBV latency. In this study three novel clones were constructed in which the ZEBRA activation region was repositioned to the carboxy terminus of the protein. These mutants were used to demonstrate that the ability of ZEBRA's wild type domain to function in the complex biological process of virus activation is not compromised by altering its position within the protein.

B-Lymphocytes↗
PubMed1998

Antioxidants inhibit the in vitro production of inflammatory cytokines in Crohn's disease and ulcerative colitis.

BACKGROUND: Modulation of cytokine secretion may be of interest in the treatment of Crohn's disease or ulcerative colitis. METHODS: The effect of three antioxidants - butylated hydroxyanisol, tetrahydropapaveroline and nordihydroguaiaretic acid - on the production of tumour necrosis factor (TNF), interleukin (IL) 1, IL-6 and IL-8 (measured by enzyme-linked immunosorbent assay) by peripheral mononuclear cells and biopsies of inflamed colonic mucosa from inflammatory bowel disease patients were studied. RESULTS: We observed a decrease in IL-1 and IL-6 production by peripheral mononuclear cells from inflammatory bowel disease patients (approximately 50% of control). The three drugs did not decrease IL-6 and IL-8 secretion by colonic biopsies, whereas they did inhibit IL-1 and, to some degree, TNF production. The cytokine-inhibitory effect of antioxidants seems to be more pronounced in ulcerative colitis than in Crohn's disease. CONCLUSION: Our results suggest that the studied antioxidants, or related compounds, may be of interest in inflammatory bowel disease treatment.

Adult↗