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Biomedical subjects

L D Lee

Publications and source records attributed to L D Lee.

30 records · Page 2Linked to original sources
PubMed1975

Isolation of the polypeptide chains of prekeratin.

Stratum corneum alpha protein, the principal structural protein of the epidermis, and its precursor prekeratin have been studied. Both proteins have similar patterns on sodium dodecyl sulfate electrophoresis and consist of several polypeptide chains (designated A, A', B, B'). These subunits have been isolated by chromatography on diethylaminoethyl cellulose in 8 M urea and characterized. Immunological studies have shown that the four subunits could be grouped into two distinct immunological groups referred to as the A and B groups and analysis of the cyanogen bromide fragments of purified components appeared to support such a hypothesis. X-ray diffraction studies have shown that at least one A component and one B component are necessary for the production of a typical alpha X-ray diffraction pattern. Circular dichroism studies have shown that the polypeptide chains of either class have low ellipticity when compared to the intact molecule, indicating that both chains are necessary for the formation of an alpha-helical structure.

Amino Acids↗
PubMed1975

The fibrous proteins in various types of ichthyosis.

The stratum corneum of individuals with ichthyosis vulgaris, sex-linked ichthyosis, lamellar ichthyosis, and epidermolytic hyperkeratosis has been studied. An alpha x-ray diffraction pattern has been observed in all specimens and the solubility of the alpha fibrous proteins appears to be the same as in normal stratum corneum. Sodium dodecyl sulfate (SDS)-polyacrylamide electrophoresis of the fibrous proteins showed variable patterns within the different types of ichthyosis, while amino acid analyses of the proteins were quite similar to those from normal stratum corneum. These data suggest that the fibrous proteins in the ichthyosis are not abnormal, but further studies on the individual polypeptide chains are necessary to rule out more subtle differences.

Amino Acids↗
PubMed1975

A genetic electrophoretic variant of human hair alpha polypeptides.

The structural proteins of hair were solubilized by reduction of disulfide bonds in 6 M urea at alkaline pH. Following conversion of the proteins to the S-carboxy-methyl derivatives, disc electrophoresis was done in 6 M urea at pH 8.3. In about 5% of the individuals studied, a variation in the normal electrophoretic pattern was observed, and this was true of hair from different body sites. An autosomal dominant mode of inheritance was found in the four families investigated. The variant pattern was not associated with any detectable change in the color, shape, stree-strain characteristics, X-ray diffraction pattern, or amino acid composition of the hair. A similar variant pattern was also observed in nail. The most likely hypothesis is that there is a polymorphism of one of the alpha polypeptides, although a mutation of a rate-determining gene cannot be excluded.

Amino Acids↗
PubMedDate not supplied

Matrix proteins of human hair as a tool for identification of individuals.

A rapid, simple, reproducible and relatively inexpensive electrophoretic technique for displaying the structural proteins of hair is described. Hairs from a large number of individuals were examined and a number of distinct differences are presented. The possibility of using these individual differences as a means of individual identification is discussed.

Electrophoresis↗
PubMedDate not supplied

Unusual results due to transfused blood.

During a murder enquiry, the forensic science investigation used PGM and EAP blood grouping systems and detected a mixture of blood on the deceased's jacket. The blood groups matched those of the deceased and accused. The results of DNA analysis, however, proved that only a single source of DNA, matching the deceased, was present. Supplementary information relating to the transfusion of the individual whilst still wearing his clothing led the authors to conclude that a mixture of transfused blood and the individual's own blood had effused from his body via a stab wound, and onto his clothing.

Blood Grouping and Crossmatching↗