Biomedical subjects

Prabhakar Vissavajjhala

Publications and source records attributed to Prabhakar Vissavajjhala.

3 recordsLinked to original sources

PubMed2005

A flexible array format for large-scale, rapid blood group DNA typing.

BACKGROUND: Typing for blood group antigens is currently performed by hemagglutination. The necessary reagents are becoming costly and limited in availability, and the methods are labor-intensive. The purpose of this study was to determine the feasibility of the use of large-scale DNA analysis in a microarray as a substitute for blood group typing. STUDY DESIGN AND METHODS: DNA, extracted from blood samples that had been phenotyped for some of the red blood cell antigens, was analyzed for selected blood group alleles by bead array (BeadChip, (BioArray Solutions Ltd., Warren, NJ) Illumina) [corrected] and by manual polymerase chain reaction (PCR)-based assays. Selected alleles were identified by enzyme-mediated elongation of probes, which were on color-encoded beads assembled into arrays on silicon chips. The performance of a prototype BeadChip (BioArray Solutions Ltd., Warren, NJ) [corrected] (BLOOD-1) containing single-nucleotide polymorphisms (SNPs) for FYA/B, FY-GATA, DOA/B, COA/B, LWA/B, DIA/B, and SC1/SC2 was verified with DNA from serologically characterized donors. It was then used to analyze more than 400 samples of partially defined phenotype. Samples from Chinese, Ashkenazi, and Thai donors (total n = 227) were tested with BLOOD-1. An expanded BeadChip (BioArray Solutions Ltd., Warren, NJ) [corrected] with a total of 18 SNPs (36 alleles; SNPs in BLOOD-1 and M/N, S/s, Lu(a)/Lu(b), K/k, FY265[for the Fy(X) polymorphism], Jk(a)/Jk(b), DO323[for Hy], DO350[for Jo(a)], and HgbS) was then evaluated with a subset of previously tested samples from Chinese, Ashkenazi, and New York blood donors (127) and an additional set of samples from Israeli donors (total n = 188). RESULTS: Results obtained by BeadChip (BioArray Solutions Ltd., Warren, NJ) [corrected] analysis were concordant with those obtained with the manual PCR-restriction fragment length polymorphism, allele-specific PCR, and hemagglutination assays. The frequencies of the alleles in the samples from different ethnic panels were within the expected ranges; however, two new DO alleles were discovered. CONCLUSION: It has been shown that microarray technology can be used to type DNA and detect new alleles in donor cohorts.

Alleles↗

PubMed2003

Glutamate receptor subunit 3 (GluR3) immunoreactivity delineates a subpopulation of parvalbumin-containing interneurons in the rat hippocampus.

Rasmussen's encephalitis is a childhood disease resulting in intractable seizures associated with hippocampal and neocortical inflammation. An autoantibody against the GluR3 subunit of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors is implicated in the pathophysiology of Rasmussen's encephalitis. AMPA receptors mediate excitatory neurotransmission in the brain and contain combinations of four subunits (GluR1-4). Although the distributions of GluR1, GluR2, and GluR4 are known in some detail, the cellular distribution of GluR3 in the mammalian brain remains to be described. We developed and characterized a GluR3-specific monoclonal antibody and quantified the cellular distribution of GluR3 in CA1 of the rat hippocampus. GluR3 immunoreactivity was detected in all pyramidal neurons and astrocytes and in most interneurons. We quantified the intensity of GluR3 immunoreactivity in interneuron subtypes defined by their calcium-binding protein content. GluR3 immunofluorescence, but not GluR1 or GluR2 immunofluorescence, was significantly elevated in somata of parvalbumin-containing interneurons compared to pyramidal somata. Strikingly, increased GluR3 immunofluorescence was not observed in calbindin- and calretinin-containing interneurons. Furthermore, 24% of parvalbumin-containing interneurons could be distinguished from surrounding neurons based on their intense GluR3 immunoreactivity. This subpopulation had significantly elevated GluR3 immunoreactivity compared to the rest of parvalbumin-containing interneurons. Electron microscopy revealed enriched GluR3 immunoreactivity in parvalbumin-containing perikarya at cytoplasmic and postsynaptic sites. Parvalbumin-containing interneurons, potent inhibitors of cortical pyramidal neurons, are vulnerable in the brains of epileptic patients. Our findings suggest that the somata of these interneurons are enriched in GluR3, which may render them vulnerable to pathological states such as epilepsy and Rasmussen's encephalitis.

Animals↗

PubMed2002

Parvalbumin-containing interneurons in rat hippocampus have an AMPA receptor profile suggestive of vulnerability to excitotoxicity.

alpha-Amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors mediate excitatory neurotransmission in the central nervous system, and contain combinations of four subunits (GluR1-4). We developed a GluR3-specific monoclonal antibody and quantified the cellular distribution of GluR3 in rat hippocampus. GluR3 immunoreactivity was detected in all pyramidal neurons and most interneurons. In addition, we found a subset of parvalbumin (PV)-containing interneurons in the hippocampus and neocortex that was notable for its intense GluR3 immunoreactivity and lack of GluR2 immunoreactivity. Such an expression pattern of AMPA receptor subunits is likely to make these interneurons selectively vulnerable to excitotoxicity.

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