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February 22, 2001
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Gene-Expression Profiles in Hereditary Breast Cancer
The use of microarrays of complementary DNA (cDNA) is a new method that reveals the thousands of genes that a tissue expresses. A microarray of 6512 cDNAs was used to study the global pattern of gene expression in breast-cancer tissue obtained from patients with germ-line mutations of the BRCA1 or BRCA2 gene, which increase susceptibility to breast cancer, and patients with sporadic breast cancer. The patterns in the tumors arising from a BRCA1 mutation were distinctly different from the patterns in tumors linked to a BRCA2 mutation.
The use of cDNA microarrays is becoming widespread, especially in studies of neoplastic tissue. The present study suggests that patterns of gene expression can distinguish BRCA1-related, BRCA2-related, and sporadic cases of breast cancer. Perhaps more intriguing, these results suggest that the two mutant genes cause breast cancer through different molecular pathways.
Related Editorial
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Genetic Variation in Alcohol Dehydrogenase and Risk of Myocardial Infarction
Alcohol dehydrogenase (ADH) is the key enzyme in the metabolism of alcohol. It exists in three isoforms (ADH1, ADH2, and ADH3). There are two genetic forms of ADH3: one oxidizes ethanol slowly, and the other quickly. In this study, men who were homozygous for the allele associated with a slow rate of ethanol oxidation and who consumed alcohol daily had higher plasma high-density lipoprotein levels and a lower risk of myocardial infarction than did men who consumed less than one drink a week and who were homozygous for the allele associated with a fast rate of oxidation.
Moderate alcohol consumption is known to reduce the risk of coronary disease, but this study shows that men with a slow rate of oxidation of ethanol, a trait that is genetically determined, accrue greater benefit from drinking alcohol than do men with a rapid rate of oxidation.
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Lack of Effect of Hypothermia after Acute Brain Injury
Whether moderate hypothermia improves the outcome in patients with acute traumatic brain injury has been debated. In this study of 392 patients with severe brain injury who were treated either with the induction of hypothermia within six hours after injury or with normothermia, there was no difference in outcome after six months of follow-up.
The notion that hypothermia might reduce the extent of the damage to neural tissue in patients who have sustained traumatic brain injuries is an attractive one, and it was supported by some studies in humans and animals. The patients in this large study may have had such severe injuries that no treatment, including hypothermia, was likely to be effective. Alternatively, perhaps hypothermia was achieved too late.
Related Editorial
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Intussusception and Oral Rotavirus Vaccine
Rotavirus is a common cause of severe gastroenteritis in infants and young children. This investigation began after nine infants were reported to have had intussusception after receiving a new oral tetravalent vaccine against rotavirus (RotaShield). In a case-control study, the risk of intussusception increased after vaccination, especially from day 3 to day 14 after the first dose (odds ratio, 21.7). The increase in risk was smaller after the second dose of the vaccine.
On the basis of this analysis, the use of this rotavirus vaccine has been suspended in the United States. The absolute risk of intussusception is small, so in developing countries where the mortality associated with rotavirus infection is substantial, the benefits of vaccination may still outweigh the newly recognized risks.
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Lung-Biopsy Tissue |
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A Mutation in the Surfactant Protein C Gene in Familial Interstitial Lung Disease
This report describes a family in which the grandfather had an illness consistent with interstitial lung disease and both the mother and child had interstitial lung disease. The surfactant protein C (SP-C ) gene from the mother and child was scanned for mutations, and both had a G-to-A transition in intron 4. Mature surfactant protein C was undetectable in the lung tissue of the child and only minimally detectable in the mother's lung tissue, indicating that the absence of surfactant protein C has a role in the pathogenesis of interstitial lung disease.
Since we know so little about the primary pathogenesis of the interstitial lung diseases, any clue to their cause will be of help in solving this puzzle. The data presented by these investigators point to surfactant protein C deficiency as a possible cause of interstitial lung disease.
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