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Biomedical subjects

M A Price

Publications and source records attributed to M A Price.

63 records · Page 4Linked to original sources
PubMed1970

Smog aerosol: infrared spectra.

Infrared spectra of smog aerosol are similar to those of sulfuric acid aerosol, but they do not show the prominent CH and carbonyl bands of organic aerosols from terpenes. Some features of the smog aerosol spectra are not present in the spectra from either type of synthetic aerosol.

Aerosols↗
PubMedDate not supplied

Use of the hydroxyl radical and gel electrophoresis to study DNA structure.

The hydroxyl radical has been used as a chemical probe to study in solution the structure of DNA and DNA-protein complexes. The hydroxyl radical abstracts a deoxyribose hydrogen atom, cleaving one strand of the DNA. The cutting pattern, visualized by separating the cleavage products using gel electrophoresis, shows the reactivity of each backbone position toward the radical. This method has been applied to studies of DNA bending and helical twist. Phased runs of adenines (adenine tracts) cause sequence-directed DNA bending. The hydroxyl radical cleavage of a bent DNA fragment containing short adenine tracts phased with the helix screw gives rise to an unusual cutting pattern. The hydroxyl radical cleavage rate decreases in the 5' to 3' direction along each adenine tract, with a minimum at the 3' end of each adenine tract. The cleavage of the matching thymine tract is similar, but the minimum in the pattern is offset in the 3' direction. This pattern on the autoradiograph of the gel is interpreted to indicate that bending is accompanied by a narrow minor groove in the DNA molecule. Furthermore, hydroxyl radical cleavage results in different cutting patterns for two similar sequences, (CGA4T4)5 and (CGT4A4)5, which have been shown to be bent and relatively straight, respectively. The hydroxyl radical method has also been used to determine the helical repeat of the metallothionein IIA gene to be about 10.5 base pairs per turn. Methods of optimizing the hydroxyl radical reaction for DNA-protein footprinting are discussed. Because individual gel bands give information about cutting frequency at particular positions in the backbone, gel resolution and clear autoradiographs are important to this work.(ABSTRACT TRUNCATED AT 250 WORDS)

Autoradiography↗
PubMedDate not supplied

Cell-mediated immunologic status of healthy members of families with a history of leprosy.

The cell-mediated immune status of 20 apparently healthy children from families with a history of leprosy has been studied. They have been compared with 20 age- and sex-matched controls from families with no history of leprosy. Lymphocyte transformation tests using PHA, PPD and lepromin and skin tests to lepromin, PPD and candida were carried out. No evidence of a depression of cell-mediated immunity in the children from families with leprosy was obtained. The only two children giving a negative Mitsuda lepromin skin test both subsequently developed leprosy in the succeeding 16 months. One was classified histologically as indefinite lepromatous and the other as borderline lepromatous. This emphasizes the practical significance of a negative lepromin skin test in an endemic leprosy area as a prognosis of clinical lepromatous leprosy.

Adolescent↗