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P Obrist

Publications and source records attributed to P Obrist.

At least 19 recordsLinked to original sources
PubMed2006

Non-invasive monitoring of kidney allograft rejection through IDO metabolism evaluation.

The immunomodulatory enzyme indoleamine 2,3-dioxygenase (IDO) is activated by interferon-gamma (IFN-gamma) and via tryptophan depletion, suppresses adaptive T cell-mediated immunity in inflammation, host immune defense, and maternal tolerance. Its role in solid organ transplantation is still unclear. Therefore, we investigated the usefulness of IDO-mediated tryptophan catabolism in the evaluation of kidney allograft rejection. Blood, urine, and tissue samples were collected from 34 renal transplant patients without rejection and from nine patients with biopsy-confirmed episodes of acute rejection (n=12). Concentrations of kynurenine and tryptophan in serum and urine were analyzed by high-pressure liquid chromatography. Kynurenine to tryptophan ratio (kyn/trp) was calculated to estimate IDO activity. Immunostaining for IDO was performed on renal biopsies. Neopterin was assessed using radioimmunoassay. Kyn/trp and neopterin were detectable at low levels in serum of healthy volunteers and were increased in non-rejecting allograft recipients. Serum levels of kyn/trp were higher in recipients with rejection compared to non-rejectors as early as by day 1 post-surgery. Rejection episodes occurring within 13+/-5.9 days after transplantation were accompanied by elevated kyn/trp in serum (114+/-44.5 micromol/mmol, P=0.001) and urine (126+/-65.9 micromol/mmol, P=0.02) compared to levels during stable graft function. Kyn/trp correlated significantly with neopterin suggesting an IFN-gamma-induced increase in IDO activity. Immunostaining showed upregulation of IDO in rejection biopsies, localized in tubular-epithelial cells. Non-rejected grafts displayed no IDO expression. Acute rejection is associated with simultaneously increased serum and urinary kyn/trp in patients after kidney transplantation. Thus, IDO activity might offer a novel non-invasive means of immunomonitoring of renal allografts.

Acute Disease↗
PubMed2006

Ep-CAM expression in pancreatic and ampullary carcinomas: frequency and prognostic relevance.

AIMS: Pancreatic adenocarcinoma is an aggressive gastrointestinal malignancy with only a few long-term survivors even after radical surgery. Patients with ampullary cancer have a better prognosis but adjuvant therapy needs further improvement. Epithelial cell adhesion molecule (Ep-CAM) is strongly expressed in a variety of epithelial cancers and represents a promising target for immunological tumour therapy. Thus, the aim of this study was to investigate Ep-CAM expression and its potential prognostic impact in pancreatic and ampullary carcinomas. METHODS: Ep-CAM expression was investigated retrospectively by immunohistochemistry in paraffin-embedded primary tumour tissue samples from a series of consecutive patients with pancreatic (n = 153) and ampullary cancer (n = 34). RESULTS: Ep-CAM overexpression was observed in 85 of 153 pancreatic cancer specimens (56%) and in 29 of 34 ampullary cancer samples (85%). Overall, Ep-CAM failed to be an independent prognostic marker. However, subgroup analyses showed that Ep-CAM overexpression correlated with shorter overall survival among patients with ampullary cancer and advanced stage pancreatic cancer. In the latter subgroup, survival gradually worsened with increasing Ep-CAM scores. Furthermore, in ampullary cancer, Ep-CAM overexpression was found to correlate with tumour stage. CONCLUSIONS: Ep-CAM overexpression was detectable in the majority of cases with pancreatic and ampullary cancer. Therefore, Ep-CAM represents an attractive target for immune-based therapeutic interventions in these tumour entities. However, the prognostic value of Ep-CAM overexpression remains undetermined.

Adenocarcinoma↗
PubMed2006

Tetrahydrobiopterin attenuates microvascular reperfusion injury following murine pancreas transplantation.

In this study we investigated the effect of tetrahydrobiopterin (BH4), an essential cofactor for nitric oxide synthases, on ischemia-reperfusion injury (IRI) following murine pancreas transplantation. Pancreatic grafts were exposed to prolonged cold ischemia times (CIT) and different treatment regimens: normal saline (S), S + 16 h CIT, BH4 50 mg/kg + 16 h CIT. Nontransplanted animals served as controls. Graft microcirculation was analyzed by means of functional capillary density (FCD) and capillary diameters (CD) after 2 h reperfusion using intravital microscopy. Quantification of inflammatory responses (mononuclear infiltration) and endothelial disintegration (edema formation) was done by histology (hematoxylin and eosin), and peroxynitrite formation assessed by nitrotyrosine immunostaining. FCD was significantly reduced after prolonged CIT, paralleled by increased peroxynitrite formation as compared with controls (all p < 0.05). Microcirculatory changes correlated significantly with intragraft peroxynitrite generation (Spearman: r = -0.56; p < 0.01). Pancreatic grafts treated with BH4 displayed markedly higher FCD values (p < 0.01) and abrogated nitrotyrosine staining (p = 0.03). CD were not significantly different in any group. Histology showed increased inflammation, interstitial edema, hemorrhage, acinar vacuolization and focal areas of necrosis after 16 h CIT, which was diminished by BH4 administration (p < 0.01). BH4 treatment significantly reduces post-ischemic deterioration of microcirculation as well as histologic damage and might be a promising novel strategy in attenuating IRI following pancreas transplantation.

Animals↗
PubMed2005

The RANKL/OPG system is activated in inflammatory bowel disease and relates to the state of bone loss.

BACKGROUND AND AIMS: A substantial proportion of patients with inflammatory bowel disease (IBD) develops osteopenia and osteoporosis in the course of disease. Recent data from a mouse model of colitis suggest that the receptor activator of nuclear factor kappa B (RANKL)/osteoprotegerin (OPG) system may be responsible for bone loss. METHODS: We investigated the activation state of the RANKL/OPG system and its association with bone loss in human IBD. Plasma levels of OPG and RANKL were correlated with bone mineral density and current IBD therapy. Colonic secretion of OPG and RANKL and cell types responsible for such secretion were determined. RESULTS: OPG plasma levels were elevated 2.4-fold in Crohn's disease (CD) and 1.9-fold in ulcerative colitis (UC) whereas soluble RANKL (sRANKL) levels were not significantly different in IBD patients compared with healthy controls. High levels of OPG were released from colonic explant cultures (CEC) derived from inflamed IBD specimens, and colonic macrophages and dendritic cells costained for OPG. sRANKL levels from CEC were low both in IBD patients and healthy controls. Interestingly, increased expression of RANKL was mainly confined to cells in the lamina muscularis. A significant negative correlation was found between OPG plasma levels and femoral neck/lumbar spine bone mineral density. CONCLUSIONS: We have demonstrated that IBD is associated with alterations in the RANKL/OPG system. Applying results from a murine model of colitis associated bone loss, the constellation of OPG and sRANKL regulation observed in our study raises the possibility that RANKL/OPG may contribute to the development of bone loss in IBD.

Adolescent↗
PubMed2004

Aberrant tetranectin expression in human breast carcinomas as a predictor of survival.

AIMS: Tetranectin (TN), a plasminogen kringle 4 binding protein, is thought to play a prominent role in the regulation of proteolytic processes via binding to plasminogen. The aim of this study was to evaluate the expression of TN in human breast cancer and adjacent normal breast tissue and to determine the impact of this expression on survival. METHODS: A retrospective analysis was performed on 189 patients with breast cancer, with a median follow up time of 10.6 years. The expression of TN was assessed in tumour tissue and adjacent normal breast tissue by immunohistochemistry, and the prognostic relevance of its expression in tumour cells was evaluated. RESULTS: TN was highly expressed in connective tissue fibres surrounding normal breast epithelium, but not in normal epithelial cells. High expression of TN in tumour cells was found in 131 (69%) of the tumour samples. By western blot analysis, no significant difference in the amount and molecular weight of TN was seen between tumour tissue and normal tissue. Strong TN immunoreactivity in tumour tissue was predictive of poor disease free and tumour specific overall survival. By multivariate analysis, high TN expression in cancer cells was an independent prognostic factor for disease free and tumour specific overall survival. CONCLUSIONS: Our results demonstrate differential TN expression in normal and malignant breast tissue and a prognostic impact of TN protein expression in breast carcinoma tissue. These data suggest a possible role of TN in invasiveness and the metastatic spread of human breast cancer.

Adult↗
PubMed2003

Her2/neu overexpression in differentiated thyroid carcinomas predicts metastatic disease.

To investigate the prognostic value of Her2/neu expression in differentiated thyroid carcinomas 103 patients were retrospectively investigated. All of them received surgical and an identical follow-up treatment. The patients with papillary and follicular thyroid cancer were further separated into two groups concerning their clinical development, including one group without distant metastasis (follow-up of minimum 8 years). The second group presented with distant metastases as a sign of an aggressive behaviour. Her2/neu was immunohistochemically detected on sections from formalin-fixed, paraffin-embedded tissues using c-erbB-2/Her-2/neu oncoprotein Ab-17 monoclonal antibody (mAb). In statistical analysis using the Mann-Whitney U-test and chi(2) test, Her2/neu protein overexpression was significantly correlated with prognosis. Both tumour entities without distant metastases showed significantly less cytoplasmic immunostaining than patients with development of metastases. Concerning the clinical outcome, Her2/neu overexpression may be regarded as a prognostic factor in differentiated thyroid carcinomas. Moreover, in addition to standard radio-iodine elimination therapy, application of Herceptin could lead to new successful therapeutic concepts for a number of patients with progressive thyroid cancer.

Adenocarcinoma, Follicular↗
PubMed2003

Correlation of COX-2 and Ep-CAM overexpression in human invasive breast cancer and its impact on survival.

Recent studies have demonstrated cyclooxygenase 2 (COX-2) overexpression in various human malignancies, especially in breast cancer, where COX-2 turned out to be a predictor of poor survival. To evaluate the relation of COX-2 and Ep-CAM overexpression and its prognostic significance, we performed a retrospective study on 212 breast cancer patients with a median follow-up time of 10.5 years. Overexpression of COX-2 in tumour tissue samples was assessed by immunohistochemistry. COX-2 overexpression was found in 48.6% of the tumour samples and was predictive for poor disease-free and overall survival. Univariate analysis revealed a strong correlation between COX-2 and Ep-CAM overexpression (P=0.009). Concurrent COX-2 and Ep-CAM overexpression was present in 21.7% of tumour specimens and had an additive negative impact on disease-free and overall survival. Determination of both tumour markers should help in guiding new therapeutic strategies in patients with invasive breast cancer.

Adult↗
PubMed2003

Distribution of DMT 1 within the human glandular system.

BACKGROUND & AIMS: DMT1 is a transmembrane protein which transports the divalent metal ions Fe2+, Zn2+, Cu2+ and Mn2+. Although DMT1 has been functionally linked to duodenal absorption and cellular utilisation of iron hardly anything is known about its distribution and potential role within the human glandular system. METHODS: Two polyclonal antibodies were raised to study the expression of DMT1 in tissues obtained from human corpus by the means of immunocytochemistry and Western blotting. RESULTS: All antibodies specifically detected a 60 kD protein band referring to human DMT1. Significant amounts of DMT1 expression were detected on the luminal site of organs, which are involved in excretion/re-absorption processes, such as salivary glands, pancreas, biliary tract and gallbladder. CONCLUSIONS: Our results suggest that DMT1 may be of pivotal importance for the regulation of metal ion homeostasis within organs involved in absorption and excretion of ions.

Animals↗
PubMed2003

Activation of the MAP kinase pathway induces chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII) expression in human breast cancer cell lines.

Growth factors are essential for cellular growth and differentiation in both normal and malignant human breast epithelial cells. In the present study we investigated the effect of epidermal growth factor (EGF), transforming growth factor alpha (TGFalpha) and phorbol myristate acetate (PMA) on chicken ovalbumin upstream promoter-transcription factor (COUP-TF) expression in human breast cancer cells. The orphan receptors COUP-TFI and COUP-TFII are members of the nuclear receptor superfamily. The high degree of evolutionary conservation of these proteins strongly argues for an important biological function. COUP-TF expression was highest in SK-BR3 cells (approximately 130 amol/ micro g total RNA), while the lowest COUP-TF expression was observed in MCF-7 cells (3.5 amol/ micro g total RNA). While treatment of EGF, TGFalpha and PMA induced expression of COUP-TFII, COUP-TFI did not respond to these agents. Oncostatin M (OSM) is known to exert an antiproliferative effect in breast cancer cells. Treatment of MCF-7 cells with OSM resulted in an approximately 90% reduction of COUP-TFII mRNA expression. In SK-BR3 cells, treatment with the MEK inhibitor UO126 resulted in a profound suppression of endogenous COUP-TFII expression. Furthermore, cotreatment with UO126 prevented induction of COUP-TFII expression by EGF in MCF-7 cells. In conclusion, our data provide evidence, for the first time, that mitogenic substances which activate the MAP kinase pathway, can induce COUP-TFII expression. Our results strongly suggest that an active MAP kinase pathway is essential for COUP-TFII expression in human breast cancer cells.

Blotting, Western↗
PubMed2003

Skin implant metastasis after percutaneous radio-frequency therapy of liver metastasis of a colorectal carcinoma.

Percutaneous radio-frequency ablation (RFA) of liver tumors has been reported to be an effective approach. Skin implant metastases have been described after RFA of hepatocellular carcinoma. A 56-year-old man underwent resection of the transverse colon for an adenocarcinoma (pT3N2M0) following by adjuvant chemotherapy. He developed multiple liver metastases and underwent RFA. Six weeks after RFA, the patient noticed a painful skin lesion at the entrance side of the probe in the right upper abdominal quadrant. Ultrasound examination and computed tomography scan revealed an intracutaneous tumor of 2-cm diameter. The tumor was excised and revealed a metastasis of the previously described adenocarcinoma. CPT-11 monotherapy was started; however, due to tumor progression, the patient died 35 months after colonic resection and 10 months after RFA. This is the first case of an implant skin metastasis after RFA of secondary liver tumors. Although RFA is a promising option in the palliation of such tumors, such rare complications have to be considered.

Adenocarcinoma↗
PubMed2002

[Pathological examination of breast biopsy specimens].

No differences for long-term disease free survival could be found between breast conserving surgery and mastectomy. Most importantly is the fact that this therapy presents a significantly higher risk for local recurrence. The characterisation of this risk is one of the most important things to do. These findings result in a widespread change in treatment of breast cancer patients. Consequently an increase in interdisciplinary working between radiologists, surgeons and pathologists could be found. Histological examinations are necessary for diagnosis and exactly evaluation of the tumor extension. Microscopic evaluation of the resection margin is of most important interest, because there is a direct connection between local recurrence and tumor infiltration of the resection margin. We performed our investigations by the use of a standardized complete embedding method with the possibility of three-dimensional reconstruction, on a cohort of 280 patients. Additionally this method allowed the detection of all relevant findings on one hand and on the other hand an evaluation of all resection margins. Our results showed a breast conserving therapy including tumor free margins was performed in 67% of the patients. But there was a second resection necessary in 57% of the cases. An extensive tumor distribution as the detection of multifocal tumor spread was the reason for mastectomy in 33%. Our findings point out the necessarily of the histological examination in the line of the complete embedding method of the breast biopsy material in order to analyse the tumor including resection margin evaluation.

Adult↗
PubMed2002

[Sonographically guided core needle biopsy of the breast: technique, accuracy and indications].

PURPOSE: The purpose of this retrospective analysis was to assess the diagnostic accuracy and complication rate of sonographically guided core needle biopsy in palpable breast masses, mammographically detected nonpalpable lesions, and sonographically detected clinically and mammographically occult lesions. PATIENTS AND METHODS: Sonographically guided core needle biopsy was performed in 590 lesions in 572 patients, by using an automated biopsy gun with a 14-gauge large core needle and a coaxial system. Core needle biopsy results were compared with surgical biopsy in 265 cases. 325 lesions with benign histologic diagnoses were followed up for at least 18 months. RESULTS: 234 carcinomas and 356 benign abnormalities were found in the 572 patients. Core needle biopsy reached a sensitivity of 98.7% at a specificity of 99.7%. Underestimation rates for lesions initially diagnosed as DCIS and for lesions initially diagnosed as ADH were 3/10 and 6/14, respectively. Of three false-negative results, two were immediately recognized, and one was identified at follow-up. Serious bleeding occurred in one patient (0.2% complication rate). CONCLUSIONS: This report confirms that sonographically guided large core needle biopsy is a safe, reliable and cost-effective method for the assessment of both palpable and nonpalpable, mammographically and sonographically detected breast abnormalities.

Algorithms↗
PubMed2001

The 4-amino analogue of tetrahydrobiopterin efficiently prolongs murine cardiac-allograft survival.

We tested the 4-amino analogue of tetrahydrobiopterin (H(4)aminobiopterin), a novel pterin-based inhibitor of nitric oxide synthases, for its efficacy in a murine cardiac-transplant model employing an improved cuff technique. We treated groups of 5 animals each for the first 7 post-operative days with various doses of H(4)aminobiopterin, with Cyclosporin A (15 mg/kg/day), or no treatment. H(4)aminobiopterin (3 times 50 mg/kg/day) proved to be as efficient as high-dose Cyclosporin A (15 mg/kg/day) in prolonging allograft survival and in suppressing histologic changes caused by the immunoreaction. Surprisingly, the doses of H(4)aminobiopterin effective in prolonging allograft survival did not change the plasma nitrite plus nitrate, or the expression of inducible nitric oxide synthase, interferon-gamma, tumor necrosis factor-alpha, and B7-1 (CD80), indicating that H(4)aminobiopterin may act through a novel, yet undiscovered mechanism.

Animals↗
PubMed2001

Expression of the duodenal iron transporters divalent-metal transporter 1 and ferroportin 1 in iron deficiency and iron overload.

BACKGROUND & AIMS: Imbalances of iron homeostasis are accompanied by alterations of intestinal iron absorption. The identification of divalent-metal transporter 1 (DMT1) and ferroportin 1 (FP1) has improved our understanding of transmembrane iron trafficking. To gain insight into the regulatory properties of these transporters in the duodenum, we studied their expression in patients with hereditary hemochromatosis (HFE-associated and non-HFE-associated), secondary iron overload, and iron deficiency. METHODS: DMT1, FP1 messenger RNA (mRNA), and protein expression were analyzed in duodenal biopsy specimens from patients by means of TaqMan real-time polymerase chain reaction, Western blotting technique, and immunohistochemistry. RESULTS: DMT1 and FP1 mRNA levels are positively correlated with each other in all patient groups (P < 0.001). Moreover, DMT1 and FP1 mRNA levels were significantly increased in patients with iron deficiency, HFE and non-HFE hemochromatosis, whereas they were unchanged in patients with secondary iron overload. Alterations in DMT1 and FP1 mRNA levels were paralleled by comparable changes in the duodenal expression of these proteins. In patients with normal iron status or iron deficiency, significant negative correlations between DMT1, FP1 mRNA, and serum iron parameters were found, which were absent in subjects with primary hemochromatosis. CONCLUSIONS: DMT1 and FP1 are centrally involved in iron uptake/transfer in the duodenum and in the adaptive changes of iron homeostasis to iron deficiency and overload.

Adult↗
PubMed2001

Epstein-Barr virus-associated extranodal NK/T-cell lymphoma, nasal type of the hypopharynx, in a renal allograft recipient: case report and review of literature.

Posttransplant lymphoproliferative disorders (PTLPDs) are predominantly B-cell lymphoproliferations, whereas a T-cell origin is rarely observed. In contrast to B-cell PTLPD, T-cell PTLPDs show an inconsistent association with Epstein-Barr virus (EBV). Until now, only 13 cases of EBV-associated T-cell PTLPDs have been reported. We describe a case of an EBV-associated T-cell PTLPD in a renal allograft recipient 2 years after transplantation. Histologic examination showed medium- to large-sized lymphoid cells with an angiocentric growth pattern and necrosis. The atypical cells showed a CD2+, CD3epsilon+, CD7+, CD43+, CD45R0+, CD56+, and CD4-, CD5-, CD8- betaF1- phenotype with expression of the latent membrane protein (LMP)-1 of EBV. In addition, EBV-specific RNAs (EBER 1/2) were identified by in situ hybridization. Molecular analysis of the T-cell receptor (TCR) gamma chain by polymerase chain reaction (PCR) showed a polyclonal pattern. The morphologic, immunohistochemical, and molecular findings were consistent with a diagnosis of an EBV-associated extranodal natural killer (NK)/T-cell non-Hodgkin lymphoma (NHL) of nasal type. To our knowledge, this is the first reported case of this rare entity in the posttransplant setting.

Aged↗
PubMed2001

Efficacy of medical therapy and antireflux surgery to prevent Barrett's metaplasia in patients with gastroesophageal reflux disease.

OBJECTIVE: To investigate whether Barrett's metaplasia may develop despite effective medical therapy. SUMMARY BACKGROUND DATA: Gastroesophageal reflux disease has a multifactorial etiology. Therefore, medical treatment may not prevent complications of reflux disease. METHODS: Eighty-three patients with reflux disease and mild esophagitis were prospectively studied for the development of Barrett's metaplasia while receiving long-term therapy with proton pump inhibitors and cisapride. Only patients who had effective control of reflux symptoms and esophagitis were included. The surveillance time was 2 years. The outcome of these 83 patients was compared with that of 42 patients in whom antireflux surgery was performed with a median follow-up of 3.5 years. RESULTS: Twelve (14.5%) patients developed Barrett's while receiving medical therapy; this was not seen after surgery. Patients developing Barrett's had a weaker lower esophageal sphincter and peristalsis before treatment than patients with uncomplicated disease. CONCLUSIONS: Antireflux surgery is superior to medical therapy in the prevention of Barrett's metaplasia. Therefore, patients with reflux disease who have a weak lower esophageal sphincter and poor esophageal peristalsis should undergo antireflux surgery, even if they have only mild esophagitis.

2-Pyridinylmethylsulfinylbenzimidazoles↗