Drug Prescribing for Patients with Chronic Kidney Disease in General Practice: a Cross-Sectional Study

Background: CpG islands methylation is the main epigenetic modification found in human tumors leading to transcriptional silencing of certain tumor suppressor genes. Reacquisition of p16/ CDKN2A tumor suppressor gene expression by 5-aza-2'-deoxycytidine results in concurrent growth inhibition of neuroendocrine pancreatic tumor cells. However, the growth suppressive effects of 5-aza-2'-deoxycytidine is unlikely to be solely attributable to the restored p16/ CDKN2A function, but rather a consequence of re-expression of additional genes silenced by de novo methylation. In an effort to validate DNA methylation as an important mechanism in neuroendocrine tumorigenesis and metastatic spread, we attempted to isolate methylation-specific transcripts in neuroendocrine pancreatic tumor cells. Methods: Differentially expressed methylation-associated genes were identified by cDNA-representational difference analysis (cDNA-RDA). Differential expression was confirmed by semi-quantitative RT-PCR using insert specific primers. Results: We identified 48 differently expressed gene fragments and methylation-associated expression was confirmed by semi-quantitative RT-PCR. 52,3% (25 of 48) showed elevated expression levels after 5-aza-2'-deoxycytidine treatment, whereas 47.7% revealed lower expression levels. 7 fragments showed homology to genes with unknown function. Interestingly, 5-aza-2'-deoxycytidine treatment led to re-expression of cofillin whereas matriptase expression levels were significantly lower. Both genes have been associated with metastastic spread and tissue invasion. The other differentially expressed genes play an unknown role in the course of neuroendocrine tumorigenesis. Conclusion: DNA methylation appears to be an important molecular mechanism in the process of neuroendocrine pancreatic tumorigenesis and metastatic spread. The definition of DNA methylation patterns associated with neuroendocrine pancreatic tumors might open up the potential for a new sensitive diagnostic tool and might serve as a new antitumor target. Copyright (C) 2007 S. Karger AG, Basel and IAP.

A bstract : The INK4a/ARF locus on chromosome 9p21 is one of the important defenses against tumor development and engages both the Rb and the p53 tumor suppressor pathways through its capacity to encode two distinct proteins, p16 INK4a and p14 ARF . Despite controversial reports, the body of present data suggests that tumor suppressors p16 INK4a and p14 ARF are targets of in‐activation in GEP‐NETs. Moreover, tumor type‐specific aberrant p16 INK4a silencing appears to be associated with advanced tumor stage and may function as a predictor of patients' outcome after surgical resection. Since conventional histological and biochemical assessment are limited with respect to predicting GEP‐NET behavior or outcome, methylation profiles including INK4a/ARF might offer a tool to refine future diagnosis and therapeutic management of GEP‐NET patients.

A bstract : The INK4a/ARF locus on chromosome 9p21 is one of the important defenses against tumor development and engages both the Rb and the p53 tumor suppressor pathways through its capacity to encode two distinct proteins, p16 INK4a and p14 ARF . Despite controversial reports, the body of present data suggests that tumor suppressors p16 INK4a and p14 ARF are targets of in-activation in GEP-NETs. Moreover, tumor type-specific aberrant p16 INK4a silencing appears to be associated with advanced tumor stage and may function as a predictor of patients' outcome after surgical resection. Since conventional histological and biochemical assessment are limited with respect to predicting GEP-NET behavior or outcome, methylation profiles including INK4a/ARF might offer a tool to refine future diagnosis and therapeutic management of GEP-NET patients.

Many studies have shown carbohydrate-deficient transferrin (CDT) to be a sensitive and specific marker of chronic alcohol abuse. We present the case of a 23-year-old, healthy professional soccer player who caused a car accident due to alcohol consumption. Several CDT test results were elevated above the laboratory reference range and were considered to be caused by alcohol intake at a level commensurate with misuse and thus license reapplication was refused. In addition, assuming chronic alcohol abuse, the young man suffered from increasing social isolation. He was finally referred to our out-patient clinic for further evaluation on the assumption of a liver disease. Since chronic alcohol consumption was denied, and there was no evidence of liver disease, a qualitative characterization of the transferrin isoforms was performed. Isoelectric focusing of serum transferrin revealed a pattern atypical for chronic alcohol intake but detected a genetically determined transferrin (Tf)-D-variant. The changed amino acid sequence caused an overlapping of transferrin isoforms with different degrees of sialylation, thus revealing false-positive serum CDT values. Determination of this Tf-D-variant heterozygosity resulted in his social rehabilitation and license reinstatement. Thus, where the evidence for alcohol dependency is either uncertain or uncorroborated, qualitative isoelectric focusing of transferrin is a useful method for analyzing unexplained CDT elevations, thus increasing the value of CDT as a marker for chronic alcoholic abuse.

Molecular mechanisms contributing to the tumorigenesis of pancreatic endocrine tumors (PETs) are still not well understood. Allelic deletions at chromosome 22q12.3 were detected in about 30-60% of PETs, suggesting that inactivation of one or more tumor suppressor genes on this chromosomal arm is important for their pathogenesis. Because the putative tumor suppressor gene tissue inhibitor of metalloproteinase-3 (TIMP-3) has been located at 22q12.3, we undertook a genetic analysis of TIMP-3 to determine its role in the tumorigenesis of PETs. Single-strand conformational polymorphism analysis, methylation-specific PCR, RNA expression analysis, and immunchistochemistry of TIMP-3 were performed in 21 sporadic PETs. Thirteen of 21 PETs (62%) revealed TIMP-3 alterations, including promoter hypermethylation and homozygous deletion. The predominant TIMP-3 alteration was promoter hypermethylation, identified, in 8 of 18 (44%) PETs. It was tumor-specific and corresponded to loss or strong reduction of TIMP-3 protein expression. Notably, 11 of 14 (79%) PETs with metastases had TIMP-3 alterations, compared with only 1 of 7 (14%) PETs without metastases (P < 0.02). These data suggest a possibly important role of TIMP-3 in the tumorigenesis of human PETs, especially in the development of metastases, which has to be further evaluated in large-scale studies.

This study evaluates the possibility of treating Bon1 and QGP pancreatic neuroendocrine tumor cells with radioactive iodide ((131)I) after stable transfection with the thyroid sodium iodide symporter (NIS). NIS expression was driven either by the strong viral cytomegalovirus promoter or by the tissue-specific chromogranin A promoter. Using either approach, NIS expression was confirmed by reverse transcription-PCR and Western blotting. Uptake of radioactive iodide was increased approximately 20-fold by chromogranin A promoter-driven NIS expression and approximately 50-fold by cytomegalovirus promoter-driven NIS expression. Maximal uptake was reached within 15 min in QGP cells and 30 min in Bon1 cells. Effective half-life was 5 min in QGP and 30 min in Bon1 cells. No evidence of organification was detected by high-performance liquid chromatography and gel filtration chromatography. (131)I was a highly effective treatment in NIS-expressing QGP and Bon1 cells, reducing clone formation by 99.83 and 98.75%, respectively, in the in vitro clonogenic assay. In contrast, clone formation was not reduced in QGP and Bon1 cells without NIS expression after incubation with the same activity concentration of (131)I as compared with mock treated cells. Absorbed doses to QGP and Bon1 cells are up to 150 and 30 Gy, respectively. In addition, a direct cytotoxic effect of radioiodide was demonstrated in NIS-expressing Bon1 cells after (131)I incubation. In conclusion, radioiodide treatment after NIS gene transfer appears to be a promising novel approach in the therapy of neuroendocrine tumors if its highly encouraging in vitro effectiveness can be transferred to the in vivo situation.

regulation by these two isoforms.Conclusion: DNA replication is regulated by licensing proteins.The MCM2 protein has been found to have a novel isoform.These two isoforms are reciprocally related during senescence and proliferation.We conclude there is a molecular switch between these two isoforms that will dictate the rate of DNA replication during senescence versus proliferation.

Human MAGE and GAGE genes encode tumor-specific antigens presented by HLA I molecules recognized on tumor cells by cytolytic T lymphocytes. To determine if pancreatic cancer patients would be suitable for MAGE-or GAGE-based immunotherapy, the expression frequency of MAGE-A1, -A2, -A3, -A4, -A6 and GAGE1-8 genes was assessed in 15 pancreatic tumor cell lines and 23 pancreatic tumor specimens using reverse transcription-polymerase chain reaction (RT-PCR). In 67% of the cell lines at least one of the MAGE-A genes was detected, 53% revealed concomitant expression of two or more genes. GAGE1–8 expression was detected in 47% of the cell lines. In the primary pancreatic tumors, MAGE-A analysis revealed exclusive MAGE-A1 and MAGE-A2 gene expression in 26 and 30% of the specimens, respectively, independent from clinicopathologic factors. Treatment of MAGE-A expression-negative pancreatic tumor cells with the demethylating agent 5-aza-2′-deoxycytid-ine could activate MAGE-A1, MAGE-A2, MAGE-A3, MAGE-A4 and GAGE transcription suggesting silencing due to promoter methylation. Interestingly, a metastatic lesion to the liver revealed concomittant expression of MAGE-A1, -A2, -A3 and -A6 consistent with a more pronounced genome-wide hypomethylation in metastases. Therefore, a subset of pancreatic cancer patients could be eligible for active, specific immunotherapy directed against MAGE-A antigens and demethylating agents could increase the number of candidate patients.

Functional inactivation of the Rb and p53 pathways appears to be a rite of passage for all cancerous cells. However, p53 and Rb alterations are rare events in neuroendocrine gastroenteropancreatic (GEP) tumors. The CDKN2 locus on chromosome 9p21 sits at the nexus of both pathways harboring tumor suppressor genes, which restrain cell growth by affecting the function of pRb and p53. Therefore, we analyzed the implication of their inactivation in 37 primary neuroendocrine GEP tumors and two cell culture models. RT-PCR analysis revealed loss of expression of at least one of the tumor suppressor genes CDKN2A/p16, CDKN2B/p15, and CDKN2D/p14 with distinct genetic profiles, most frequently in nonfunctional pancreatic tumors (57%) and small intestinal carcinoids (44%), and less commonly in insulinomas (30%) and gastrinomas (22%). DNA analysis and methylation-specific PCR attributed loss of expression to either homozygous deletion or 5'CpG island hypermethylation. 5-Aza-2-deoxycytidine treatment reversed CDKN2A/p16 and CDKN2B/p15 silencing with concurrent growth restraint. Thus, tumor suppressor genes localized in the 9p21 gene cluster are specific targets of inactivation in neuroendocrine GEP tumors, and demethylating agents might hold promise for selective therapy.

Primary prevention is the most effective approach to reduce the incidence of pancreatic cancer. Epidemiological studies have contributed to the identification of risk factors for pancreatic cancer, suggesting an association with age, various medical conditions, environmental and lifestyle risk factors, and occupational and genetic conditions. Age is the strongest risk factor. The most consistently identified environmental risk factor is smoking, but there is less certainty concerning dietary factors. Studies have suggested a positive association with high energy intake, cholesterol and meat, while vegetable and fruit intakes are probably protective. Patients with chronic pancreatitis and new onset of diabetes mellitus have a low but increasing risk of having or developing pancreatic cancer. There is strong evidence for the association of hereditary pancreatitis or cystic diseases of the pancreas and pancreatic cancer. A family history of pancreatic cancer is an important risk factor, but only a small proportion can be linked with known familial cancer syndromes. Thus, additional yet unidentified predisposing risk factors have to be assumed

Germline mutations of the MEN1 gene have been identified as the causative genetic defect of multiple endocrine neoplasia type I (MEN-I), an autosomal dominantly inherited condition. To establish the basis for predictive family screening we evaluated the spectrum of MEN1 gene mutations in MEN-I patients treated at our institution. Relatives at risk were subjected to predictive genetic screening after genetic counseling. Gene carriers were subjected to extensive clinical screening for MEN-I, including biochemical tests for basal hormone concentrations in blood and urine, a standardized meal stimulation test and imaging procedures (ultrasonography, computed tomography, magnetic resonance imaging). Among index patients of 15 independent MEN-I kindreds, 14 heterozygous MEN1 germline mutations were identified by single-strand conformational variant analysis (SSCV) and direct DNA sequence analysis. Of 51 individuals at risk, 26 predictively tested relatives with the wild-type MEN1 gene could be excluded from further screening procedures because they had not inherited the disease. In all previously presumed unaffected relatives with the mutant gene, our extensive clinical screening program revealed at least one manifestation of MEN-I. Furthermore, 22 additional diagnoses could be established in identified MEN-I patients. We show that mutation analysis enables predictive genetic screening for MEN-I families, providing a valuable tool for genetic counseling and clinical management. An extensive clinical screening program focusing on genetically proven individuals at risk allows detection of MEN-I manifestations at an early, asymptomatic stage of the disease. Controlled, prospective studies are now required to prove whether timely appropriate treatment on the basis of predictive screening might help improve disease-related quality of life and prolong life expectancy in MEN-I kindreds.

Tumors arising from the pancreatic islet cells are rare and represent a heterogeneous group of benign or malignant lesions. Most tumors present with well characterized syndromes, whereas others appear to be nonfunctioning. The clinical features of 11 men and 7 women with nonfunctioning islet cell carcinomas operated on between 1983 and 1998 were reviewed. The median patient age was 53.5 years (range 26–74 years). The most frequent presenting symptoms were abdominal pain (13 patients), weight loss (7 patients), and obstructive jaundice (4 patients). Gut hormone profiles were normal in all patients. Abdominal sonography and computed tomography localized the tumor in 17 patients, and correct prediction of an endocrine tumor was achieved in 12 patients. Six of seven patients showed a hypervascular tumor upon angiograpy, and seven of eight patients preoperatively had positive somatostatin receptor scintigraphy. At operation, regional or distant metastases were present in 15 (83%) and 6 (33%) patients, respectively. Eleven patients underwent potentially curative resections, and the remaining seven patients were managed palliatively by resection (four patients) or bypass procedures (three patients). Three patients had up to three more resection for metastases. Eight patients received postoperative octreotide, interferon α therapy, or both. The overall cumulative 5- and 10-year survival rates were 65.4% and 49.1%, respectively. Of the 11 patients who underwent curative resection, 10 were alive after a median follow-up of 63 months (range 7–180 months), but only 5 are free from disease. Although surgical cure is rare in nonfunctioning islet cell carcinomas, significant long-term palliation can be achieved in a large proportion of patients with an aggressive surgical approach and, when indicated, additional medical therapy.

Background: Somatostatin and its long-acting analogues are effective in symptom control in patients with functionally active neuroendocrine GEP tumours. Several in vitro and in vivo reports suggest that they are also able to control tumour growth. Methods: Critical review of published data on the effect of long-acting somatostatin analogues on symptom and growth control in patients with metastatic neuroendocrine GEP tumours. Results: With the exception of insulinoma and gastrinoma, octreotide acetate and other long-acting somatostatin formulations are currently the therapeutic principle of first choice to control hormone-mediated symptoms. The consequences of gastric acid hypersecretion in patients with Zollinger-Ellison syndrome are best controlled by proton pump inhibitors. Available data on growth control indicate that stabilization of tumour growth seems to be the most beneficial antiproliferative effect occurring in up to 50% of patients. This effect is limited. However, it is unknown which tumour entity responds best to long- acting somatostatin analogues. Conclusion: Additional studies in patients with known spontaneous tumour growth and avoiding a mix-up of different entities of neuroendocrine malignancies are necessary to identify subpopulations of neuroendocrine tumours which respond to long-acting somatostatin analogues in terms of longer lasting growth inhibition.