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H T Butler

Publications and source records attributed to H T Butler.

6 recordsLinked to original sources
PubMed2003

Association of the androgen receptor CAG repeat polymorphism with Alzheimer's disease in men.

We examined the CAG repeat polymorphism in exon 1 of the androgen receptor (AR) in an Oxford cohort of 150 cases (101 men) of definite or probable Alzheimer's disease (AD) and 190 elderly controls (140 men). We found that short alleles (< or = 20 CAG repeats) were associated with AD (adjusted odds ratio = 2.5, 95% confidence intervals: 1.2-5.0) in men, but not in women. This association appeared stronger in early-onset AD (< 65 years). We conclude that this AR polymorphism is of potential relevance to the risk of AD in men.

Aged↗
PubMed2000

A direct regional scale estimate of transgene movement from genetically modified oilseed rape to its wild progenitors.

One of the major environmental concerns over genetically modified (GM) crops relates to transgene movement into wild relatives. The pattern of hybridization ultimately affects the scale and rapidity of ecological change and the feasibility of containment. A new procedure for quantifying hybrid formation over large areas is described. Remote sensing was used to identify possible sites of sympatry between Brassica napus and its progenitor species across 15 000 km2 of south-east England in 1998. Two sympatric populations with B. rapa and one with B. oleracea were found over the entire survey area. Every newly recruited plant in these populations in 1999 was screened for hybrid status using flow cytometry and molecular analyses. One hybrid was observed from the 505 plants screened in the B. rapa populations but none of the nine B. oleracea recruits were hybrids. Measures to minimize gene flow are suggested, and a procedure for the post-release evaluation and containment of GM cultivars is proposed.

Brassica↗
PubMed1985

Determination of polycyclic aromatic hydrocarbons in environmental samples by high performance thin-layer chromatography and fluorescence scanning densitometry.

High performance thin-layer chromatography (HPTLC) with fluorescence scanning densitometry was used for the quantitative determination of polycyclic aromatic hydrocarbons in the soluble organic fraction of air particulate samples. A method using normalized emission response ratios was developed to determine sample identity and to test for peak homogeneity. To preserve the high sample throughput of HPTLC, the two-point calibration method was used for quantitation. The principal advantages of HPTLC as a screening technique for environmental samples are its low cost, methodological simplicity, high sample throughput, and the ability to analyze crude samples with a minimum amount of sample cleanup.

Air Pollutants, Occupational↗
PubMed1984

Comparison of methods for separating polycyclic aromatic hydrocarbons by high-performance thin-layer chromatography.

A comparison is made of different stationary phases (silica gel, cellulose, acetylated cellulose, and 3-aminopropyl-, ethyl-, octyl-, octadecyl-, and diphenylsilanized silica gel), mobile phases, and development techniques (conventional, continuous, and multiple) for the separation of environmentally important polycyclic aromatic hydrocarbons by high-performance thin-layer chromatography. Reversed-phase separations using octadecylsilanized silica gel and methanol-water or methanol-water-based ternary solvent systems were found to give the best separations. A new development technique, multiple development with application of the mobile phase further up the plate at each successive development, provided superior resolution of the polycyclic aromatic hydrocarbons compared with conventional multiple development.

Cellulose↗