The MAS proto-oncogene is imprinted in human breast tissue

The human MAS proto-oncogene is situated at 6q25.3-q26, a region that is homologous to mouse chromosome 17 where two parentally imprinted genes (Mas and Igf2r) have previously been identified. We investigated the imprinting status of MAS in adult lesions to establish the imprinting status of this gene in humans, as certain imprinted genes are known to have altered imprinting phenotypes in cancer. Of 14 breast samples demonstrating a MAS RT-PCR product, 4 were informative for a polymorphic marker. In all 4 cases, expression of the MAS gene was found to be mono-allelic, indicating the presence of a functional imprint at this locus in human breast tissue.     

Lung and kidney cancer mortality associated with arsenic in drinking water in Córdoba, Argentina

We have deleted the chromosomal rpsA gene, encoding ribosomal protein S1, from an Escherichia coli strain carrying a plasmid where rpsA was controlled by the lac promoter and operator. This exogenous source of protein S1 was essential for growth. Thus we have verified the absolute requirement for protein S1. To see if translation of individual mRNAs differed in the requirements for protein S1, we removed the inducer and followed the time-course of the synthesis of several individual proteins and of total RNA, DNA and protein. Growth immediately shifted from being exponential to being linear, with a rate of protein synthesis defined by the pre-existing amount of protein S1. The expression pattern of the individual proteins indicated that the translation of all mRNAs was dependent on protein S1. Unexpectedly, we found that depletion for protein S1 for extended periods introduced a starvation for amino acids. Such starvation was indicated by an increased synthesis of ppGpp and could be reversed by addition of a mixture of all 20 amino acids. Measurements of the peptide chain elongation rate in vivo showed that ribosomes without protein S1 were unable to interfere with the peptide chain elongation rate of the active ribosomes and that, therefore, protein S1 was unable to diffuse from one ribosome to another during translation. We conclude that protein S1-deficient ribosomes are totally inactive in peptide chain elongation on most, if not all, naturally occurring E. coli mRNAs.     

Hyperbaric oxygen and thrombolysis in myocardial infarction: the ''HOT MI'' randomized multicenter study

Reactions mediated by the brain are part of the response to intraperitoneal administration of endotoxin, a model of gram-negative bacterial infection. To test the hypothesis that a compromised blood-brain barrier (BBB) may contribute to these reactions, the integrity of the BBB was measured following lipopolysaccharide administration. Rats received intraperitoneal injections of 50 microg/kg or 2 mg/kg of endotoxin. Brain uptake of a macromolecular vascular marker, 3H-labelled rat serum albumin, and of a poorly permeable low molecular weight substance, [14C]sucrose, was then measured with the intravenous bolus injection method. Compared to controls, neither dose of endotoxin affected the BBB permeability for these tracers. This was true when brain uptake was measured 5 min or 2 h after lipopolysaccharide injection. It is concluded that intraperitoneal endotoxin even at a high dose does not acutely disrupt the BBB.     

Electron-beam computed tomography: preliminary experiences in the Netherlands]

The difference between computer tomography (CT) and electron beam tomography (EBT) is that for CT the x-ray tube rotates in a ring round the patient, and for EBT the x-ray beam rotates itself. As a result, with EBT the speed of making images is not limited by the mechanical rotation of the tube, and 16 images can be made per second. An EBT scan of a whole thorax takes 9 seconds. Specific application areas are fast moving organs and patients who cannot remain in one position for long, e.g. children and intensive care patients. Research is being conducted into the possibilities of this non-invasive technique for the demonstration of coronary artery lesions, pulmonary embolism, pulmonary metastases and dynamic examination of the major respiratory tract. Costs of an EBT scan currently amount to Dfl. 450.--but they will probably decrease as this imaging system is developed further. The exposure to radiation is about the same as that caused by a (spiral) CT.     

Endopeptidase inhibitors decrease myocardial ischemia/reperfusion injury in an in vivo rabbit model

Periods of ischemia followed by reperfusion of the ischemic tissue are associated with myocardial damage and ventricular arrhythmia. Angiotensin converting enzyme inhibitors limit the occurrence of these arrhythmias. The protective effects of angiotensin converting enzyme inhibitors may be due to inhibition of bradykinin (BK) degradation, rather than inhibition of angiotensin II formation. Other enzymes which catabolize BK include the endopeptidases EP24.11 and EP24.15. The purpose of this study was to determine if inhibitors of EP24.11 and EP24.15 decrease ischemia/reperfusion injury and if this protection is mediated by BK receptors. Rabbits were anesthetized and prepared for recording of cardiovascular parameters. The chest was opened and a left ventricular artery occluded for 30 min, followed by a 2-hr reperfusion period. Infarct size was determined using triphenyl tetrazolium chloride staining immediately after reperfusion. The enzyme inhibitors, ramiprilat, N-[1-(R,S)-carboxy-3-phenylpropyl]-Phe-pAB, and N[1-(R,S)-carboxy-3-phenylpropyl]-Ala-Ala-Phe-pAb, singly and in combinations were administered 3 min before reperfusion. Compared to saline (32.1 +/- 2.1), ramiprilat (18.3 +/- 2.8) and the EP inhibitors (14.4 +/- 1.4 for the combination) significantly decreased infarct size, with the greatest decrease occurring when all three inhibitors were combined (10.6 +/- 1.5). The protective effect of the EP inhibitors was blocked by the BK2 receptor antagonist, HOE 140 (30.1 +/- 2.6). Enzyme assays demonstrated EP24.11 and EP24.15 in the rabbit heart. We conclude that the EP inhibitors decreased ischemia/reperfusion injury by protecting BK from metabolism and that a combination of inhibitors provides superior protection to that given by a single agent.     

Thoracic tumors in children with neurofibromatosis-1

Lymphocytes were isolated from volunteers before and after receiving a single supplement of vitamin C, vitamin E or beta-carotene. The lymphocytes were treated with H2O2, and DNA strand breaks were measured by single cell gel electrophoresis (the comet assay). Significant protection against oxidative DNA damage was evident 2-4 h after vitamin C intake, and 18-24 h after consumption of the other antioxidants. Lymphocytes from smokers were more sensitive to DNA damage than those from non-smokers, and they showed at least as great a protective effect with antioxidants.