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Biomedical subjects

R Baumann

Publications and source records attributed to R Baumann.

At least 55 records · Page 3Linked to original sources
PubMed1998

Significance of diminished factor XIII in Crohn's disease.

OBJECTIVE: Coagulation factor XIII is a plasma transglutaminase involved in crosslinking of fibrin, the last step of the coagulation system and a connective tissue factor contributing to the wound healing process. It circulates as a heterotetrameric molecule consisting of two identical proenzyme subunits (factor XIIIA) and two carrier protein subunits (factor XIIIS). The aim of this study was to determine the disease features associated with the diminution of factor XIII in Crohn's disease. METHODS: Factor XIIIA and factor XIIIS levels were assessed in patients presenting with Crohn's disease, ulcerative colitis, infectious colitis, or diverticulitis, in patients with rheumatoid arthritis, and in control subjects. Prothrombin fragment 1 + 2 assay, as a marker of the generation of thrombin and measurement of C-terminal telopeptide of type I collagen as an estimate of degradation of collagen type I, were performed. RESULTS: Factor XIIIA was significantly decreased in Crohn's disease, in ulcerative colitis, and in infectious colitis by comparison with subjects presenting with diverticulitis, normal, and rheumatoid subjects p = 0.0001). Factor XIIIS was unmodified in patients with Crohn's disease by comparison with controls but was reduced in those presenting with intestinal bleeding (p = 0.0002). In Crohn's disease, the lowest level of factor XIIIA was observed in patients with intestinal bleeding (p = 0.0003). Factor XIIIA was correlated with the Van Hees index (r = -0.5661; p = 0.0001) and with the C-terminal telopeptide of type I collagen (r = -0.4110; p = 0.0011) but not with prothrombin fragment 1 + 2. The multiple regression analysis showed that only Van Hees index and intestinal bleeding were independent variables for explaining the diminution of Factor XIIIA in Crohn's disease. CONCLUSIONS: Factor XIIIA subunit is an indicator of Crohn's disease activity. Our study suggests that a low factor XIIIA level is related to the presence of intestinal lesions and might be linked to intestinal repair mechanisms; loss in intestinal lumen could be also involved, especially in patients with intestinal bleeding.

Adolescent↗
PubMed1998

[Spontaneous hyperintensity of the anterior pituitary gland in MRI T1-weighted images related to manganese deposits in a patient undergoing prolonged parenteral nutrition].

The signal abnormalities found on MRI in the basal ganglia in patients with an increased plasmatic level of manganese are well known. We report a case with a hyperintense signal in a patient with a high plasmatic level of manganese due to long term parenteral nutrition. The normal signal intensity of T2-weighted imaging in the anterior pituitary gland helps to differentiate the increased signal intensity of T1 weighted imaging due to deposition of manganese from hemorrhagic or fatty lesions.

Adult↗
PubMed1997

Atrial septal defect in adults: cardiopulmonary exercise capacity before and 4 months and 10 years after defect closure.

OBJECTIVES: The purpose of the study was to evaluate the cardiopulmonary exercise capacity and ventilatory function in adults with atrial septal defect (ASD) preoperatively and 4 months and 10 years postoperatively. BACKGROUND: Only few data are available on cardiopulmonary exercise tolerance after ASD closure, but detailed knowledge might be helpful for indication for defect closure in certain patients. METHODS: The study was performed in adult patients (mean [+/-SD] age at operation 39.9 +/- 11.5 years; left-right shunt 9.6 +/- 5.6 liters/min; pulmonary/systemic flow ratio 2.8 +/- 1.2; mean pulmonary artery pressure 18.2 +/- 6.2 mm Hg). Cardiopulmonary exercise testing was performed with a bicycle ergometer. We determined peak oxygen uptake, anaerobic threshold, performance at anaerobic threshold and maximal performance in relation to these variables in a normal group. Ventilatory function at rest was expressed by vital capacity, maximal voluntary ventilation and forced expiratory volume in 1 s. RESULTS: Preoperatively, ventilatory function at rest was only moderately reduced to approximately 75% to 85%. Four months postoperatively we found no significant improvement, but 10 years postoperatively ventilatory function at rest was normalized. Preoperative cardiopulmonary exercise capacity was markedly reduced to 50% to 60%; early postoperatively it was only slightly higher, but late postoperatively exercise capacity significantly improved and was completely normalized. CONCLUSIONS: Although preoperative cardiopulmonary capacity in adult patients with nonrestrictive ASD was significantly decreased, some improvement was seen at 4 months postoperatively, with complete restitution to normal at 10 years after shunt closure.

Adult↗
PubMed1997

Antral and fundic D-cell numbers in Helicobacter pylori infection.

OBJECTIVES: Helicobacter pylori infection is associated with an exaggeration of gastrin release following meals or bombesin stimulation attributed to a defect of somatostatin secretion of antral D-cells. Nevertheless, these modifications of gastric physiology do not explain the increase of gastric acid secretion which is only observed in duodenal ulcer patients. The inhibitory effect of somatostatin secretion of fundic D-cells on parietal cells is well known. The aim of our prospective study was to compare the number of fundic D-cells and likewise the number of antral G-cells and D-cells between patients with duodenal ulcer and healthy subjects with and without H. pylori infection. METHODS: The numbers of D-cells and G-cells were compared between 19 infected patients with duodenal ulcer and 20 healthy subjects, 10 with and 10 without H. pylori infection. Fundic mucosal biopsy specimens were examined using immunohistochemical techniques specific for the presence of somatostatin, antral mucosal biopsy specimens for the presence of gastrin and somatostatin. RESULTS: The number of G-cells was significantly lower (P = 0.0012) in duodenal ulcer patients by comparison with infected subjects and controls. The number of antral D-cells was significantly less (P < 0.0001) in duodenal ulcer patients (mean of 10 random fields = 0.45 +/- 0.04) than in either asymptomatic infected patients (0.65 +/- 0.07) or uninfected controls (0.88 +/- 0.10). The number of fundic D-cells was significantly lower (P < 0.0001) in duodenal ulcer patients (mean = 0.20 +/- 0.03) than in either asymptomatic infected subjects (0.29 +/- 0.05) or controls (0.73 +/- 0.09); here the difference between the two groups of infected subjects was not significant. Multivariate analysis showed that the presence of H. pylori infection of the fundic mucosa did not influence the number of fundic D-cells. CONCLUSION: Changes in the number of fundic and antral D-cells induced by H. pylori infection did not explain abnormalities of gastric acid secretion usually observed in duodenal ulcer patients; it is suggested that pre-existing abnormalities in the regulation of parietal cell or increase of parietal cell mass are involved.

Adult↗
PubMed1997

Figure-ground segregation at contours: a neural mechanism in the visual cortex of the alert monkey.

An important task of vision is the segregation of figure and ground in situations of spatial occlusion. Psychophysical evidence suggests that the depth order at contours is defined early in visual processing. We have analysed this process in the visual cortex of the alert monkey. The animals were trained on a visual fixation task which reinforced foveal viewing. During periods of active visual fixation, we recorded the responses of single neurons in striate and prestriate cortex (areas V1, V2, and V3/V3A). The stimuli mimicked situations of spatial occlusion, usually a uniform light (or dark) rectangle overlaying a grating texture of opposite contrast. The direction of figure and ground at the borders of these rectangles was defined by the direction of the terminating grating lines (occlusion cues). Neuronal responses were analysed with respect to figure-ground direction and contrast polarity at such contours. Striate neurons often failed to respond to such stimuli, or were selective for contrast polarity; others were non-selective. Some neurons preferred a certain combination of figure-ground direction and contrast polarity. These neurons were rare both in striate and prestriate cortex. The majority of neurons signalled figure-ground direction independent of contrast polarity. These neurons were only found in prestriate cortex. We explain these responses in terms of a model which also explains neuronal signals of illusory contours. These results suggest that occlusion cues are used at an early level of processing to segregate figure and ground at contours.

Animals↗
PubMed1997

Activation domain requirements for disruption of Epstein-Barr virus latency by ZEBRA.

Latent infection of B lymphocytes by Epstein-Barr virus (EBV) can be disrupted by expression of the EBV ZEBRA protein. ZEBRA, a transcriptional activator, initiates the EBV lytic cascade by activating viral gene expression. ZEBRA is also indispensable for viral replication and binds directly to the EBV lytic origin of replication. The studies described herein demonstrate that the activation domain. ZEBRA activation can be replaced by a heterologous acidic, proline-rich, or glutamine-rich activation domain. ZEBRA activation domain swap constructs retain ZEBRA's native abilities to activate specific EBV promoters, to disrupt EBV latency, and to stimulate replication at the EBV lytic origin. Additional work, employing sequential and internal deletions of ZEBRA's N-terminal activation domain, indicates that its separate activities are not attributable to specific subdomains but are spread throughout its N terminus and therefore cannot be inactivated by deleting localized regions.

B-Lymphocytes↗
PubMed1997

In vitro effects of oxpentifylline on inflammatory cytokine release in patients with inflammatory bowel disease.

BACKGROUND: Inflammatory cytokines, including tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1 beta, have been implicated as primary mediators of intestinal inflammation in inflammatory bowel disease. AIM: To investigate the in vitro effects of oxpentifylline (pentoxifylline; PTX; a phosphodiesterase inhibitor) on inflammatory cytokine production (1) by peripheral mononuclear cells (PBMCs) and (2) by inflamed intestinal mucosa cultures from patients with Crohn's disease and patients with ulcerative colitis. METHODS: PBMCs and mucosal biopsy specimens were cultured for 24 hours in the absence or presence of PTX (up to 100 micrograms/ml), and the secretion of TNF-alpha, IL-1 beta, IL-6, and IL-8 determined by enzyme linked immunosorbent assays (ELISAs). RESULTS: PTX inhibited the release of TNF-alpha by PBMCs from patients with inflammatory bowel disease and the secretion of TNF-alpha and IL-1 beta by organ cultures of inflamed mucosa from the same patients. Secretion of TNF-alpha by PBMCs was inhibited by about 50% at a PTX concentration of 25 micrograms/ml (IC50). PTX was equally potent in cultures from controls, patients with Crohn's disease, and those with ulcerative colitis. The concentrations of IL-6 and IL-8 were not significantly modified in PBMCs, but IL-6 increased slightly in organ culture supernatants. CONCLUSIONS: PTX or more potent related compounds may represent a new family of cytokine inhibitors, potentially interesting for treatment of inflammatory bowel disease.

Adult↗
PubMed1997

Alternative system for detection and mapping of activation domains.

The ZEBRA protein is a transcriptional activator that induces expression of viral lytic genes in cells harboring latent Epstein-Barr virus (EBV). In this report it is shown that a derivative of ZEBRA that cannot activate transcription (Zd) can be used to detect and characterize activation domains. Three expression vectors that allow the fusion of putative activation regions in any reading frame were constructed using Zd. These vectors were used to demonstrate the activity of different classes of activation domains using a chloramphenicol acetyltransferase (cat) reporter gene construct containing seven ZEBRA response elements (Z7). The Zd/Z7 system effectively detected proline-rich, glutamine-rich and acidic activation domains in a variety of cell lines and cell types. Using a bioassay unique to the EBV Zd/Z7 system, fusion constructs can also be tested for the ability to activate gene expression directly from a chromatin structure, the EBV genome. These studies indicate that the Zd/Z7 system is an alternative to GAL4 and can be a useful tool for identifying heterologous activation domains.

Base Sequence↗
PubMed1997

Nonmalignant epithelial cells, potentially invasive in human endometriosis, lack the tumor suppressor molecule E-cadherin.

Endometriosis is one of the most frequent diseases in gynecology. It is a histologically defined nonmalignant disease in which endometrium-like tissue is found outside the uterus (for example, peritoneum, gut, or lung). The pathogenesis of endometriosis is unknown, but invasive mechanisms have been implicated in the development of the disease. Indeed, primary cells from human endometriotic biopsies but not from human endometrial biopsies are invasive in an in vitro collagen invasion assay. In this study, these in vitro invasive endometriotic cells were found to be nonmalignant epithelial cells lacking E-cadherin, which acts as an invasion suppressor molecule in carcinomas. Immunocytochemistry showed that the E-cadherin-negative epithelial cell type was increased in sections of endometriosis tissue as compared with sections of eutopic endometrium. On the basis of these data we propose that the E-cadherin-negative invasive endometriotic cells seen in vitro represent the cell population that migrates to ectopic (extrauterine) locations and thus causes endometriosis in vivo. Accordingly, the loss of E-cadherin expression is postulated to constitute a crucial mechanism in the pathogenesis of endometriosis.

Cadherins↗
PubMed1997

Does endometrial resection help dysmenorrhea?

BACKGROUND: Menorrhagia is a common symptom and is often associated with dysmenorrhea. METHODS: The effect of transcervical resection of the endometrium (TCRE) on dysmenorrhea associated with menorrhagia was investigated in a prospective study. Ninety consecutive women were monitored before surgery and for a period of up to 12 months after resection. The amount of pelvic pain experienced was scored daily on a scale of 0-3, and was timed in relation to menstruation. RESULTS: There was a significant decrease in the level of pain experienced during menstruation and overall during the menstrual cycle (p < 0.001), but not in the premenstruum. The effect on pain was immediate and was maintained throughout the follow-up period of the study. The presence of adenomyosis or leiomyomata in the surgical specimen did not influence the beneficial effect on pain. CONCLUSIONS: Based on these findings, dysmenorrhea during menstruation should not be a contraindication to transcervical endometrial resection in women with menorrhagia.

Adult↗
PubMed1997

[Interleukin-8 is an important inflammatory mediator in hemorrhagic rectocolitis and Crohn disease].

OBJECTIVES: The aim of the study was to assess in vitro the production of interleukin 8 in Crohn's disease and ulcerative colitis. PATIENTS AND METHODS: Interleukin 8 concentrations (measured by ELISA) were evaluated in the culture supernatants of: a) peripheral blood mononuclear cells from 13 patients with Crohn's disease, 7 patients with ulcerative colitis and 7 controls, b) organ cultures of inflamed (22 Crohn's disease, 15 ulcerative colitis) and uninflamed (21 Crohn's disease, 9 ulcerative colitis, 15 controls) intestinal mucosal biopsies. RESULTS: In patients with Crohn's disease and ulcerative colitis, the production of interleukin 8 by peripheral blood mononuclear cells and inflamed mucosa was higher than in controls (P < 0.01) without statistical difference between Crohn's disease and ulcerative colitis. Interleukin 8 production by normal mucosa was not different between the 3 groups. Interleukin 8 concentrations in the supernatants of organ culture were positively correlated to an endoscopical and a histological inflammatory index as well as to tumor necrosis factor, interleukin 1 and 6 concentrations. CONCLUSION: These results support the notion that interleukin 8 plays an important role in the pathogenesis of inflammatory bowel disease.

Adult↗
PubMed1997

[Treatment with cyclosporine of severe colitis in hemorrhagic rectocolitis. Apropos of 7 cases].

Cyclosporin has been suggested as an alternative treatment in severe acute ulcerative colitis. In a retrospective study, the outcome of seven ulcerative colitis patients treated by intravenous cyclosporin (mean dose 3.6 mg/kg/day) has been evaluated. Short-term results indicated full remission in 3/7 (43%) patients. At long term follow-up (one year), only 2/7 patients could avoid ileal pouch-anal anastomosis. Two complications (one colonic perforation and one septicemia) were observed. Our results suggest that intravenous cyclosporin should not be recommended as a standard therapy in severe acute ulcerative colitis. Its use has to be limited in patients presenting a major contraindication for surgery and has to be performed by those experienced in both immunosuppressive treatment and inflammatory bowel disease.

Acute Disease↗
PubMed1996

Mucosal inflammatory cytokine production by intestinal biopsies in patients with ulcerative colitis and Crohn's disease.

Chronic inflammation in inflammatory bowel disease (IBD; Crohn's disease and ulcerative colitis) may be attributed partly to increased secretion of inflammatory cytokines. The aim of this study was to investigate simultaneously the spontaneous release patterns of tumor necrosis factor-alpha (TNF-alpha), interleukin-1-beta (IL-1 beta), and interleukin-6 (IL-6) by organ cultures of inflamed mucosa from IBD patients. Organ cultures of involved IBD mucosa spontaneously produced increased amounts of TNF-alpha, IL-1 beta, and IL-6 compared to normal mucosa. The patterns of cytokine release between Crohn's disease and ulcerative colitis organ cultures were not significantly different. Increased inflammatory cytokine production by lamina propria mononuclear cells (LPMCs) and mucosa treated with EDTA suggests that these cytokines originate mainly from LPMCs. These results confirm the role of inflammatory cytokines in IBD and shed a new light on the role of TNF-alpha in IBD.

Adult↗