Biomedical subjects

S R Head

Publications and source records attributed to S R Head.

5 recordsLinked to original sources

PubMed2006

An association of candidate gene haplotypes and bleeding severity in von Willebrand disease type 2A, 2B, and 2M pedigrees.

We analyzed the association of bleeding severity with candidate gene haplotypes within pedigrees of 11 index cases of von Willebrand disease (VWD) type 2 (two type 2A, three type 2B and six type 2M), using the QTL Association model (MENDEL 5.5). In addition to the 11 index cases, these pedigrees included 47 affected and 49 unaffected relatives, as defined by VWF mutations and/or phenotype. A bleeding severity score was derived from a detailed history and adjusted for age. Donors were genotyped using a primer extension method, and eight candidate genes were selected for analysis. VWF antigen (or ristocetin cofactor activity) levels had the strongest influence on bleeding severity score. After Bonferroni correction for multiple testing, only ITGA2 promoter haplotype -52T was associated with an increased bleeding severity score (P < 0.01). This association remained statistically significant when the three type 2B pedigrees were excluded (P = 0.012) or when gender-specific bleeding categories were excluded (P < 0.01). The major haplotypes of seven other candidate genes, GP1BA, ITGA2B, ITGB3, GP6, VWF, FGB, and IL6, were not associated with bleeding severity. These results establish that genetic differences in the expression of the integrin subunit alpha2 can influence the bleeding phenotype of VWD type 2 and complement our previous findings in VWD type 1. Genetically controlled attenuation of platelet collagen receptor expression can influence risk for morbidity in clinical settings where hemostasis is compromised.

Adolescent↗

PubMed2002

Analysis of result variability from high-density oligonucleotide arrays comparing same-species and cross-species hybridizations.

There exists a significant limitation in the variety of organismsfor which microarrays have been developed because of a lack of genomic sequence data. A near-term solution to this limitation is to use microarrays designed for one species to analyze RNA samples from closely related species. The assumption is that conservation of gene sequences between species will be sufficient to generate a reasonable amount of good-quality data. While there have been relatively few published reports describing the use of microarrays for cross-species hybridizations, this technique is potentially a powerful tool for understanding genomics in model organisms such as nonhuman primates. Here we describe the analysis and comparison of hybridization characteristics and data variability from a set of cross-species (rhesus macaque) and same-species (human) hybridization experiments using human high-density Affymetrix oligonucleotide arrays. The data reveal that a large fraction of probe sets are effective at transcript detection in the cross-species hybridization, validating the application of cross-species hybridizations for nonhuman primate genomics research.

Analysis of Variance↗

PubMed1999

Solid-phase sequence scanning for drug resistance detection in tuberculosis.

DNA chip arrays hold considerable promise for diagnostic sequencing of polymerase chain reaction (PCR) products. To date, however, arrays have been relatively expensive, complex to use and difficult to interpret, preventing their adaptation to the clinical lab. A moderate density array method has been developed that enables efficient, easy-to-interpret and robust solid-phase PCR product sequencing. Here, the results of Mycobacterium tuberculosis rifampin resistance mutation detection by primer-extension-based sequence scanning of the rpo B gene of M. tuberculosis are presented. Rifampin resistant clinical isolates were identified in as little as 1 h post PCR amplification with visual results detection.

Bacterial Proteins↗

PubMed1997

Nested genetic bit analysis (N-GBA) for mutation detection in the p53 tumor suppressor gene.

There is a growing and significant demand for reliable, simple and sensitive methods for repeated scanning of a given gene or gene fragment for detection and characterization of mutations. Solid-phase sequencing by single base primer extension of nested GBATM primers on miniaturized DNA arrays can be used to effectively scan targeted sequences for missense, insertion and deletion mutations. This paper describes the use of N-GBA arrays designed to scan the sequence of a 33 base region of exon 8 of the p53 gene (codons 272-282) encompassing a hot spot for mutations associated with the development of cancer. Synthetic DNA templates containing various missense, insertion and deletion mutations, as well as DNA prepared from pancreatic and biliary tumor cells, were genotyped using the exon 8 arrays.

Adenocarcinoma↗

PubMed1996

[Magnuson-Stack operation for chronic anterior shoulder instability].

Between the years 1975-1992 we operated on 30 cases of recurrent anterior dislocation of the shoulder by the Magnuson-Stack procedure, using the subscapularis tendon. 23 patients (25 shoulders) have since been followed for an average of 5 years. We developed a comprehensive shoulder rating scale to evaluate functional status of involved shoulders. By this rating system the results were excellent in 73.9% of the cases, good in 17.4% and fair in 8.7%. The operation is technically simple, rapid, had no complications and is at least as effective as other operations.

Adolescent↗