Evolution and distribution of RNA polymerase II regulatory sites from RNA polymerase III dependant mobile Alu elements

BACKGROUND: The primate-specific Alu elements, which originated 65 million years ago, exist in over a million copies in the human genome. These elements have been involved in genome shuffling and various diseases not only through retrotransposition but also through large scale Alu-Alu mediated recombination. Only a few subfamilies of Alus are currently retropositionally active and show insertion/deletion polymorphisms with associated phenotypes. Retroposition occurs by means of RNA intermediates synthesised by a RNA polymerase III promoter residing in the A-Box and B-Box in these elements. Alus have also been shown to harbour a number of transcription factor binding sites, as well as hormone responsive elements. The distribution of Alus has been shown to be non-random in the human genome and these elements are increasingly being implicated in diverse functions such as transcription, translation, response to stress, nucleosome positioning and imprinting. RESULTS: We conducted a retrospective analysis of putative functional sites, such as the RNA pol III promoter elements, pol II regulatory elements like hormone responsive elements and ligand-activated receptor binding sites, in Alus of various evolutionary ages. We observe a progressive loss of the RNA pol III transcriptional potential with concomitant accumulation of RNA pol II regulatory sites. We also observe a significant over-representation of Alus harboring these sites in promoter regions of signaling and metabolism genes of chromosome 22, when compared to genes of information pathway components, structural and transport proteins. This difference is not so significant between functional categories in the intronic regions of the same genes. CONCLUSIONS: Our study clearly suggests that Alu elements, through retrotransposition, could distribute functional and regulatable promoter elements, which in the course of subsequent selection might be stabilized in the genome. Exaptation of regulatory elements in the preexisting genes through Alus could thus have contributed to evolution of novel regulatory networks in the primate genomes. With such a wide spectrum of regulatory sites present in Alus, it also becomes imperative to screen for variations in these sites in candidate genes, which are otherwise repeat-masked in studies pertaining to identification of predisposition markers

Acute necrotising pancreatitis as the first and sole presentation of undiagnosed primary hyperparathyroidism

Primary hyperparathyroidism is a recognized, but rare, cause of acute pancreatitis. The pathophysiology of hypercalcemia-induced acute pancreatitis is not well known, but when this combination occurs, pancreatitis is likely to be severe and the degree of hypercalcemia may play an important role in this association. Therefore, the cause of hypercalcemia should be identified early. Surgical resection of the parathyroid adenoma is the ultimate therapy. We report two cases with severe acute necrotizing pancreatitis associated with hypercalcemia. The cause of hyperparathyroidism was a benign parathyroid adenoma. We highlight the drawbacks in delaying the diagnosis of primary hyperparathyroidism in patients with acute pancreatitis as the sole clinical presentation

Histopathological study of lung in autopsy cases: a prospective study

Background: Present days the air pollution and other environmental inhalants, chemical cum toxic substances become uncontrollable. The lungs are involved in a number of infectious, inflammatory and occupational diseases. But involved in almost all cases of terminal events due to cardiovascular causes. Autopsy is an important tool in identifying the cause and manner of death and hence to establish the preventive methods. The aim of this study was to analyse the findings by the histopathological examination in lung tissue received in autopsy specimens.Methods: This study is a prospective study done on 100 autopsy cases received in the Department of Pathology, Chengalpattu medical College for a period of 6 months during July to December 2013. Gross findings were noted during autopsy and specimen was subjected to routine processing and Hematoxylin and Eosin Stain. Histopathological findings were noted.Results: Of the 100 cases, 40% shows pneumonia, 28% shows congestion, 16% shows emphysema, 2% shows normal finding. 14% cases show overlapping. Males were more commonly affected than females.Conclusions: From this study of autopsy specimens of lung the most common findings were pneumonia, emphysema, and congestion. Pneumonia was found to be the most common finding in the study. We should plan to prevent the causes and reduce the prevalence of pneumonia. Educational counseling should be given on exposure of environmental pollutants to the people