Biomedical subjects

Q Vu

Publications and source records attributed to Q Vu.

5 recordsLinked to original sources

PubMed2000

The accumulation of dendritic cells in the lung is impaired in CD18-/- but not in ICAM-1-/- mutant mice.

Bone marrow-derived dendritic cell (DC) precursors migrate via the blood stream to peripheral tissues to adopt their sentinel function. To identify factors facilitating their emigration to the lung, mutant mice deficient in E-selectin, P-selectin, E/P-selectin, ICAM-1, or CD18 and their respective controls were examined. DCs and monocytes/macrophages were immunolabeled with M5/114 and MOMA-2 mAbs, respectively, and quantified morphometrically. Of these genotypes, the numbers of DC and MOMA-2+ cells were significantly less only in the lungs of CD18-/- mice by 68 and 35% in alveolar walls and by 28 and 26% in venous walls, respectively. DCs were reduced by 30 and 41% around large and small airways, respectively, but the number of MOMA-2+ cells in these locations was not significantly different from controls. Ablation of a single gene may be associated with augmented expression of other, related gene products. Therefore, we examined the expression of VCAM-1. Increased numbers of arteries exhibited continuous luminal VCAM-1 staining in both CD18-/- and ICAM-1-/- mutants. VCAM-1 expression was absent in pulmonary capillaries and unchanged in veins. These data suggest that under nonperturbing conditions, CD18-mediated adhesion is required for the full complement of DC precursors to accumulate in the lungs. However, the defect in CD18-/- mice is partial, suggesting that CD18-independent adhesion occurs. The alternative pathway may involve VLA-4/VCAM-1 in arteries and venules but not in capillaries. The smaller defect in ICAM-1-/- mice suggests that the CD11/CD18 complex recognizes ligands other than ICAM-1 at some sites.

Animals↗

PubMed2000

Data acquisition, data storage, and data presentation in a modern genetics laboratory.

Modern genetic analysis can be divided into three main areas of investigation. The first is data acquisition, in the form of genomic sequence and the cataloguing of polymorphism data of the single nucleotide polymorphism variety (so called SNPs). Once identified, such genetic information can be adapted into high throughput tests to examine genetic information in large populations, making the analysis of sufficiently large numbers both cost and time effective so that relatively low-penetrant genetic effects can be accurately detected. The third step is correlating variation with phenotype (e.g. disease susceptibility or resistance) for a variety of disorders is paramount in our motivation and indeed is a common goal of modern human genetic analysis. While the technology to acquire vast amounts of genetic data is now well established and continues to expand, the ability to deal with such data, from the process of acquisition, storage, and analysis depends fundamentally on a solid informatics infrastructure as an essential component. Indeed, most of the major gains in productivity in this field are to be realized on the informatics front, and involve automating data acquisition, defining and sorting data in databases for quality control and analysis and facilitating access to data for the large variety of data analyses. Informatics-related issues including those relating to data acquisition, database structure, and analysis tools are summarized here in an effort to define some of the issues relevant to establishing informatics infrastructure in a small genetics laboratory focused on resequencing human immune response genes. From inherited diseases to drug efficacy to the specific genetic changes occurring during tumor development, this new field of medical genetics promises a profound impact on the state of human health. Ultimately, any and all advances in this field will continue to depend on major investments in informatics.

Computational Biology↗

PubMed1999

Mapping HLA for single nucleotide polymorphisms.

Knowledge of DNA sequence variation may help us understand how genetic variability gives rise to functional variability and, in so doing, revolutionize the development of strategies to combat and prevent disease. Single nucleotide polymorphisms (SNPs) are stable, inherited, biallelic, single base pair differences which are present in the human genome at a density of 1 to 10 per 1,000 nucleotides. It is anticipated that SNPs will account for much of the functional heterogeneity in gene expression and protein activity exhibited in the human population. Susceptibility to or protection from a number of diseases, particularly those of autoimmune etiology, has been associated with specific alleles of the human leukocyte antigen (HLA) complex. Interestingly, the precise molecular defects in the HLA genes are unknown and the notion that non-HLA genes, within the same chromosomal region, are involved remains a formal possibility. We have determined the nucleotide sequence of a contiguous 2.2 Mbp segment of chromosome six that includes all of the HLA class I region, and have identified over 10,000 SNPs therein. Because of the derivative knowledge of gene and SNP content and position, the scientific community is now uniquely poised to identify disease-contributory SNPs that lie within the MHC.

HLA Antigens↗

PubMed1998

Dendritic cell precursors are enriched in the vascular compartment of the lung.

The vast mucosal interface separating external from internal compartments of the lung is under the surveillance of a population of blood-borne, bone marrow-derived dendritic cells (DC) characterized by constant turnover. Because these sentinel cells process foreign antigens that have penetrated the epithelial barrier and transport them to local lymph nodes, they require continuous replenishment by blood-borne cells. In the present study, the phenotype and function of DC and their precursors isolated from the vascular compartment of the lung were examined and compared with those in vena cava blood. Intravascular leukocytes were retrieved by exhaustive perfusion of the lung vasculature. Leukocytes harvested from the subdiaphragmatic vena cava of the same animal served as a source of DC in prepulmonary blood. Typical, large, major histocompatibility class II+ antigen (MHC II+) DC constituted < 1% of leukocytes from either vascular compartment. These cells expressed intercellular adhesion molecule [ICAM]-1 and lymphocyte function-associated antigen [LFA]-1 and many were ED1(+) (lysosomal antigen in monocytes, macrophages, and some DC). No ED2(+) cells (macrophages) were identified. Very few of the circulating DC expressed the alpha-like subunit of integrin recognized by the OX62 monoclonal antibody. A striking difference appeared when neutrophil-depleted leukocytes were cultured with granulocyte macrophage colony-stimulating factor (GM-CSF) for 3 d; the number of MHC II+ DC generated from pulmonary vascular leukocytes was 76% greater than that from the vena cava population. After pulse-labeling with tritiated thymidine ([3H]TdR) followed by 3 d of culture with GM-CSF, DC from either source remained virtually unlabeled, as determined by autoradiography. On the day of harvest, DC and their precursors obtained from either vascular compartment were poor stimulators of the mixed leukocyte reaction and required GM-CSF for development of their full accessory cell capability. These data suggest that, relative to leukocytes in vena cava blood, those in the lung vascular compartment are enriched in a population of mononuclear cells that are capable of differentiating into MHC II+ DC when exposed to the appropriate growth factors, including GM-CSF. This enriched population of DC precursors could represent a source from which lung DC may be readily recruited not only to replenish the normally turning-over mucosal DC, but also to participate in inflammatory reactions occurring in the lung.

Animals↗

PubMed1994

Multisite reproducibility of colorimetric broth microdilution method for antifungal susceptibility testing of yeast isolates.

MICs of fluconazole and amphotericin B were determined independently for 100 coded yeast isolates by each of six laboratories to determine reproducibility of results by using a colorimetric oxidation-reduction-based broth microdilution test. In addition, each site tested five quality control isolates on at least four different occasions during the study. Results agreed within a three-dilution range (mode +/- 1 log2 dilution) for 96.2% of fluconazole tests and 92.7% of amphotericin B tests. Agreement among tests with the quality control isolates was 99.4% with fluconazole and 98.6% with amphotericin B. These results indicate that the colorimetric microdilution method is reproducible among laboratories.

Amphotericin B↗