Biomedical subjects

J W Galloway

Publications and source records attributed to J W Galloway.

3 recordsLinked to original sources

PubMed1991

Macromolecular asymmetry.

The helix is the most common and the most readily recognized example of an enantiomorphic structure. Helical proteins and DNA are good examples of structures where a clear explanation can be provided as to why they adopt one hand or the other. Proteins and DNA are composed of chiral building blocks, amino acids and nucleotides, respectively. Only the L-amino acids occur in proteins; this uniformity of handedness is a prerequisite for helix formation and thus, one could argue, for the development of higher life forms. Helical proteins form higher order helical structures, from collagen and viral capsids to cotton fibres.

Amino Acids↗

PubMed1991

Changing trends in thyroid surgery. 38 years' experience.

Although fine needle aspiration (FNA) of thyroid masses has been performed since the 1950s, only recently has it become a common method of diagnosing thyroid malignancy. To assess the trends in thyroid surgery during the last 38 years at this institution, a retrospective study of the total number of cases during 2-year periods of each decade were reviewed, yielding 509 cases. Results showed that the total number of cases and the type of surgical procedure remained stable until recent years when FNA was more commonly used. For the 1987-1988 period, the total number of cases decreased (from an average of 112 per period in 1950-1981 to 60 in 1987-1988), but the percentage of cases with carcinoma was markedly increased (from 6.3% in 1950-51 to 46.7% in 1987-88). The percentage of total thyroidectomies performed increased due to a preoperative pathological diagnosis afforded by FNA. A decrease in surgical complications was also seen (from an average of 4.5% per period in 1950-1981 to 1.6% in 1987-1988). FNA has been shown to reduce the number of patients requiring surgery, increase the percentage of carcinoma in operative cases, increase the number of total thyroidectomies, and increase the percentage of preoperative pathologic diagnoses.

Adenocarcinoma↗

PubMed1989

Reflections on the ambivalent helix.

The helix is nature's favourite shape. Because of its elementary geometry and distinctive appearance it is also the clearest instance of an enantiomorphic object--a helix and its mirror image are identical in all respects except their screw sense. This is a distinction that can be ignored from the points of view of pure geometry and pure group theory but any helical structure is actually available as either or both hands. Whether in nature helices do occur as just one hand, or both, is one of the best--perhaps the best--puzzles of the science of form. In this short review I look at a few examples of naturally occurring helices, some where only one hand is found, some where both are commonly found, and perhaps the most interesting examples in biological terms--those where both are found but one hand is very much rarer than the other. I review what mechanisms--physico-chemical, genetic, evolutionary--underlie the different manifestations of left- and right-handedness.

Animals↗