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Biomedical subjects

R W Cotton

Publications and source records attributed to R W Cotton.

7 recordsLinked to original sources
PubMed1992

Isolation of deoxyribonucleic acid (DNA) from saliva and forensic science samples containing saliva.

Saliva and saliva-stained materials were examined as potential sources of deoxyribonucleic acid (DNA) for DNA analysis and identity testing. In this paper, the authors demonstrate that DNA was isolated and DNA banding patterns suitable for DNA typing were obtained from fresh saliva and various saliva-stained materials, such as envelopes, buccal swabs, gags, and cigarettes. Furthermore, DNA and DNA banding patterns were obtained from actual forensic evidentiary samples containing mixed saliva/semen stains. The DNA banding patterns obtained from saliva or saliva-stained material were indistinguishable from the patterns obtained from blood or hair from the same individual. Intact DNA was readily isolated and DNA banding patterns were obtained from saliva stored at -20 degrees C and dried saliva stains stored under varying conditions. We conclude that saliva and saliva-stained material can be good sources of DNA for analysis and for DNA typing in certain forensic settings.

Autoradiography↗
PubMed1990

Use of deoxyribonucleic acid (DNA) fingerprints for identity determination: comparison with traditional paternity testing methods--Part II.

Six red blood cell (RBC) antigen systems, coupled with human lymphocyte antigen (HLA) phenotyping, were used to establish paternity on 28 mother/child/alleged-father trios. Samples were subsequently examined using the deoxyribonucleic acid (DNA) fingerprinting test with the multilocus Jeffreys DNA probes 33.6 and 33.15. In 27 of 28 paternity cases, the DNA fingerprinting test results supported and enhanced the results of RBC and HLA typing by resolving disputed paternity cases conclusively. One discrepancy between conventional serological methods and DNA analysis is discussed.

Blood Grouping and Crossmatching↗
PubMed1990

Use of deoxyribonucleic acid (DNA) fingerprints for identity determination: comparison with traditional paternity testing methods--Part I.

A study involving comparison of the deoxyribonucleic acid (DNA) finger-printing test with traditional methods used for paternity testing is presented. Samples from 191 cases were tested for a series of blood group and polymorphic protein markers. DNA "fingerprints" were then obtained for all samples using the multilocus probes 33.6 and 33.15. The results of DNA fingerprinting correlated well with those of traditional methods and proved to be informative in cases where traditional methods yielded inconclusive or insufficient results.

Autoradiography↗
PubMed1988

Review of the molecular biology of the human alcohol dehydrogenase genes and gene products.

Using protein and enzymatic methods, a major role in ethanol metabolism was assigned to the alcohol dehydrogenase (ADH) enzymes. Three major classes of ADHs were described on the basis of structure and function, including timing and location of expression. Polymorphic variants, including a common functional variant, were identified. Molecular cloning allowed the demonstration of a high degree of sequence homology between the three class I ADH genes and enabled the definition of ADH variants at the DNA sequence level. The existence of an ADH gene cluster on chromosome 4 and the shared evolutionary roots of these genes suggests that the continued integration of studies of the different ADH genes will yield further insights into alcohol metabolism in humans.

Alcohol Dehydrogenase↗
PubMed1981

Nucleosome dissociation at physiological ionic strengths.

Monomer nucleosomes purified on isokinetic sucrose gradients are shown to dissociate into component DNA and histones at physiological ionic strength upon dilution to a DNA concentration below 20 microgram/ml. The starting material is 11S, contains 145-190 BP DNA, and equimolar amounts of the four core histones with slightly less H1. Dilution of monomers in the presence of 0.14 M NaCl results in the rapid conversion of 10-40% of the 3H thymidine labeled material from 11S to 5S (5S is coincident with the S value of monomer length DNA). The proportion of nucleosomes which dissociate increases with increasing NaCl concentration between 0.15 M and 0.35 M and decreases with increasing DNA concentration above 1 microgram/ml. Recycling 11S monomers, which remain after dissociation, through a second dilution in salt generates an equivalent proportion of 5S material as seen after the initial dilution. Thus, the dissociation does not result from special properties of a subset of nucleosomes. An equilibrium between intact monomer and free DNA and histones appears to be rapidly established under the conditions described and the dissociated DNA will reassociate with histones to form 11S monomers if conditions of high DNA concentration and low ionic strength are established.

Animals↗
PubMed1980

Electron microscopic analysis of RNA transcription in preimplantation rabbit embryos.

We have examined directly RNA synthesis in several stages of preimplantation rabbit embryos by electron microscopic analysis of chromatin spreads. DNA/chromatin packing ratios were determined for non-transcribing regions (2.0) and for regions active in RNA synthesis (1.1). Significant amounts of RNA transcription were observed in all embryonic stages examined. Lengths of transcribed regions were calculated and range from 1.1 to 10.9 Kb of B-form DNA. The frequency of chromatin-associated ribonucleoprotein (RNP) fibrils was greatly reduced in samples prepared from embryos treated with alpha-amanitin indicating that the RNPs observed were growing chains. The frequency of single and multiple RNP fibrils attached to chromatin is the same at all stages examined implying the absence of extensive modulation of RNA chain initiation. These results are discussed in relation to the biochemical data on RNA synthesis in preimplantation rabbit embryos.

Animals↗