Johns Hopkins University

About: Johns Hopkins University is a education organization based out in Baltimore, Maryland, United States. It is known for research contribution in the topics: Population & Health care. The organization has 110248 authors who have published 249247 publications receiving 14084474 citations. The organization is also known as: The Johns Hopkins University & Johns Hopkins.

Identification of a chromosome 18q gene that is altered in colorectal cancers

Abstract: Allelic deletions involving chromosome 18q occur in more than 70 percent of colorectal cancers. Such deletions are thought to signal the existence of a tumor suppressor gene in the affected region, but until now a candidate suppressor gene on this chromosomal arm had not been identified. A contiguous stretch of DNA comprising 370 kilobase pairs (kb) has now been cloned from a region of chromosome 18q suspected to reside near this gene. Potential exons in the 370-kb region were defined by human-rodent sequence identities, and the expression of potential exons was assessed by an "exon-connection" strategy based on the polymerase chain reaction. Expressed exons were used as probes for cDNA screening to obtain clones that encoded a portion of a gene termed DCC; this cDNA was encoded by at least eight exons within the 370-kb genomic region. The predicted amino acid sequence of the cDNA specified a protein with sequence similarity to neural cell adhesion molecules and other related cell surface glycoproteins. While the DCC gene was expressed in most normal tissues, including colonic mucosa, its expression was greatly reduced or absent in most colorectal carcinomas tested. Somatic mutations within the DCC gene observed in colorectal cancers included a homozygous deletion of the 5' end of the gene, a point mutation within one of the introns, and ten examples of DNA insertions within a 0.17-kb fragment immediately downstream of one of the exons. The DCC gene may play a role in the pathogenesis of human colorectal neoplasia, perhaps through alteration of the normal cell-cell interactions controlling growth.

A promoter-level mammalian expression atlas

Abstract: Regulated transcription controls the diversity, developmental pathways and spatial organization of the hundreds of cell types that make up a mammal Using single-molecule cDNA sequencing, we mapped transcription start sites (TSSs) and their usage in human and mouse primary cells, cell lines and tissues to produce a comprehensive overview of mammalian gene expression across the human body We find that few genes are truly 'housekeeping', whereas many mammalian promoters are composite entities composed of several closely separated TSSs, with independent cell-type-specific expression profiles TSSs specific to different cell types evolve at different rates, whereas promoters of broadly expressed genes are the most conserved Promoter-based expression analysis reveals key transcription factors defining cell states and links them to binding-site motifs The functions of identified novel transcripts can be predicted by coexpression and sample ontology enrichment analyses The functional annotation of the mammalian genome 5 (FANTOM5) project provides comprehensive expression profiles and functional annotation of mammalian cell-type-specific transcriptomes with wide applications in biomedical research

Isolation of intracellular membranes by means of sodium carbonate treatment: application to endoplasmic reticulum.

Abstract: A rapid and simple method for the isolation of membranes from subcellular organelles is described. The procedure consists of diluting the organelles in ice-cold 100 mM Na2CO3 followed by centrifugation to pellet the membranes. Closed vesicles are converted to open membrane sheets, and content proteins and peripheral membrane proteins are released in soluble form. Here we document the method by applying it to various subfractions of a rat liver microsomal fraction, prepared by continuous density gradient centrifugation according to Beaufay et al. (1974, J. Cell Biol. 61:213-231). The results confirm and extend those of previous investigators on the distribution of enzymes and proteins among the membranes of the smooth and rough endoplasmic reticulum. In the accompanying paper (1982, J. Cell Biol. 93:103-110) the procedure is applied to peroxisomes and mitochondria.

Screened poisson surface reconstruction

Abstract: Poisson surface reconstruction creates watertight surfaces from oriented point sets. In this work we extend the technique to explicitly incorporate the points as interpolation constraints. The extension can be interpreted as a generalization of the underlying mathematical framework to a screened Poisson equation. In contrast to other image and geometry processing techniques, the screening term is defined over a sparse set of points rather than over the full domain. We show that these sparse constraints can nonetheless be integrated efficiently. Because the modified linear system retains the same finite-element discretization, the sparsity structure is unchanged, and the system can still be solved using a multigrid approach. Moreover we present several algorithmic improvements that together reduce the time complexity of the solver to linear in the number of points, thereby enabling faster, higher-quality surface reconstructions.

Projected cancer risks from computed tomographic scans performed in the United States in 2007.

Abstract: Methods: Risk models based on the National Research Council’s “Biological Effects of Ionizing Radiation” report and organ-specific radiation doses derived from a national survey were used to estimate age-specific cancer risks for each scan type. These models were combined with age- and sex-specific scan frequencies for the US in 2007 obtained from survey and insurance claims data. We estimated the mean number of radiationrelatedincidentcancerswith95%uncertaintylimits(UL) using Monte Carlo simulations. Results:Overall,weestimatedthatapproximately29000 (95% UL, 15000-45000) future cancers could be related to CT scans performed in the US in 2007. The largest contributions were from scans of the abdomen and pelvis (n=14 000) (95% UL, 6900-25 000), chest (n=4100) (95% UL, 1900-8100), and head (n=4000) (95% UL, 1100-8700), as well as from chest CT angiography (n=2700) (95% UL, 1300-5000). One-third of the projectedcancerswereduetoscansperformedattheages of 35 to 54 years compared with 15% due to scans performed at ages younger than 18 years, and 66% were in females.