Ras gene mutations in intraductal papillary neoplasms of the pancreas: analysis in five cases
The identification of cancer-causing genes in some viruses (oncogenes) has quickly led to the identification of genes with similar structures in normal, healthy cells. These genes may be found to be altered in some forms of cancer. The ras gene, one of the normal so-called proto-oncogenes (capable of causing cancer), has been found to carry mutations in 94 percent of adenocarcinomas of the pancreas which have been studied. This high proportion of mutant genes has led to a search for similar mutations in intraductal papillary carcinoma of the pancreas, a form of pancreatic cancer that is far less common than the pancreatic adenocarcinoma. Five specimens of intraductal papillary carcinoma of the pancreas were obtained and tested for mutations of the ras gene using techniques of molecular biology. Mutations could be identified in three of the five specimens (60 percent), indicating that the gene is abnormal in a significant proportion of these cancers, but apparently in fewer than in the adenocarcinoma. In this small sample, no correlation was found between the mutant genes and the appearance of abnormal cells under the microscope. However, there did seem to be a correlation between the size of the tumor and the occurrence of mutations. The two cancers without mutant ras genes were also the two smallest cancers. One interpretation of this observation is that the mutation of the ras gene is not necessary for the malignant transformation of cells in the development of the intraductal papillary carcinoma of the pancreas. However, such mutations may increase in likelihood as the cancer grows. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Cancer
MR imaging of small hepatocellular carcinoma: effect of intratumoral copper content on signal intensity
Magnetic resonance (MR) imaging is a technique used to produce images of soft tissues of the body. MR is very useful in diagnosing the various types of liver tumors, such as hepatocellular carcinoma (HCC). On one type of MR image known as T1-weighted, HCC appears as an area of high intensity compared with normal tissue. One theory as to why HCC shows a high-intensity signal pattern on T-1 images is that this tumor contains a higher concentration of metals with magnetic properties, such as copper, than the surrounding tissue. MR images were obtained from 112 patients with HCCs smaller than 5 centimeter (cm). Tumor samples were obtained to determine copper content and other characteristics. HCC tumor signal intensities on T1 images were low in 43 patients (38.4 percent), the same as surrounding tissue in 16 patients (14.3 percent), high in 45 patients (40.2 percent), and mixed in 8 patients (7.1 percent). Examination of tumor tissue showed that steatosis (fat tissue degeneration) and clear cell formation were significantly greater in tumors with high-intensity patterns. Copper and iron concentrations were significantly higher in tumors that had high-intensity patterns than in tumors with other intensity patterns. These results indicate that the difference in signal intensities seen on T1 MR images of HCC may be due to varying concentrations of copper in the tumor. The significance of the variations in copper content of tumors requires more elucidation. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Radiology
Effect of Inhaled Nitric Oxide on Gas Exchange in Patients with Congestive Heart Failure: A Randomized, Controlled Trial
Nitric oxide may be beneficial in patients with congestive heart failure. Researchers randomly assigned 16 patients with congestive heart failure to inhale nitric oxide gas or receive intravenous isosorbide dinitrate. Isosorbide dinitrate is a drug that relaxes blood vessels. Nitric oxide increased blood oxygen levels and decreased carbon dioxide levels. It also lowered blood pressure in the lungs. In contrast, isosorbide dinitrate lowered blood pressure in the lungs but had no effect on oxygen or carbon dioxide levels.
Publication Name: Annals of Internal Medicine
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