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Biomedical subjects

B K Machida

Publications and source records attributed to B K Machida.

4 recordsLinked to original sources
PubMed1992

Revision rhinoplasty. An analysis of aesthetic deformities.

Revision rhinoplasty can present difficult and challenging problems, which maximally test the skill and judgment of the facial plastic surgeon. We conducted a retrospective study of 1221 consecutive rhinoplasties, of which 170 were revision procedures. The rate of revision of our own procedures is 5.3%. Postrhinoplastic deformities are divided anatomically into the upper, middle, and lower thirds of the nose. The largest category of deformities occur in the lower thirds of the nose, in which bossa are the most common problem. Overall, pollybeak is the most common deformity in 33% of the procedures performed, followed by bossa in 26%, and excessive dorsal removal in 24%. We analyzed the causes and selected management of these cases.

Female↗
PubMed1991

Immediate versus chronic tissue expansion.

A quantitative comparison of the effects on tissues is performed between chronic tissue expansion, intraoperative expansion, and load cycling in a guinea pig model. Intra-operative expansion, which was developed by Sasaki as a method of immediate tissue expansion for small- to medium-sized defects, and load cycling, which was described by Gibson as a method using intraoperative pull, are compared with chronic tissue expansion on the basis of the following four parameters: amount of skin produced, flap viability, intraoperative tissue pressures, and histological changes. The chronically expanded group, which included booster and nonbooster expansions, produced a 137% increase in surface area, or a 52% increase in flap arc length, whereas intraoperative expansion resulted in a 31% increase in surface area, or a 15% increase in flap arc length. The load-cycled group, however, resulted in an almost negligible amount of skin increase. All three techniques exhibit immediate postexpansion stretchback. Flap viability is not impaired by any of the three techniques, in spite of the elevated pressures observed during expansion. Therefore, intraoperative expansion is effective primarily for limited expansion of small defects, whereas chronic tissue expansion still provides the greatest amount of skin increase when compared with other techniques.

Animals↗
PubMed1980

Sex difference in human mevalonate metabolism.

Two pathways of mevalonate metabolism have been demonstrated: the major (sterol) pathway leads to cholesterol synthesis, whereas the second shunts mevalonate away from sterol production and ultimately results in its oxidation to CO2. Previous studies have demonstrated that the female rat metabolizes circulating mevalonate by the shunt pathway at twice the rate of the male, whereas the male rat converts significantly more circulating mevalonate to cholesterol than the female. The present study extends these observations to humans. Six men and five premenopausal women with normal renal function were injected with R,S-[5-14C]mevalonate, and 14CO2 expired in the breath of the subjects was monitored continuously with an ionization chamber. On an average, the female subjects expired 16.5% and the males 9.8% of the injected R-[5-14C]mevalonate (P less than 0.001). No differences were observed in the plasma and erythrocyte [14C]cholesterol levels. These data demonstrate, in human beings, a sex difference in mevalonate metabolism. The overall impact of the greater mevalonate shunt activity on cholesterol balance in women is unknown.

Adult↗