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Biomedical subjects

K Motegi

Publications and source records attributed to K Motegi.

At least 109 records · Page 6Linked to original sources
PubMed1984

Relation between cleavage lines and scar tissues.

As viewed in relation to cleavage lines, the histological structure of scar tissues, whether old or new, closely simulates the structure of a cable. Bundles of collagen fibres, the main component of scar tissue, that run at right angles to the direction of the cleavage lines, may be likened to a cable core while fibres that surround the main structure of the scar tissue, parallel with the direction of the cleavage lines, may be likened to the coating material of a cable.

Adolescent↗
PubMed1984

Consideration of the formation and biological significance of hypertrophic scar.

An incision placed at right angles to the direction of skin cleavage lines is susceptible to the development of a haematoma within the sutured wound. Moreover, the edges of the sutured incision are not firmly fixed together by the material and the sutured incision is subjected to direct tension. For these 3 reasons an incision not conforming with the direction of skin cleavage lines may frequently allow stretching and postoperative hypertrophy of a scar. The biological function of a young hypertrophic scar may be an expansion-relaxation movement of the capsule of scar tissue like a bellows, at right angles to the direction of skin cleavage lines in near, though not quite, synchronism with the surrounding dermis. The biological function of a mature scar may be a movement of the scar tissue in exact synchronism with the dermis as activated by the combination of a bellows-like movement of the capsule of scar tissue in the direction at right angles to the skin cleavage lines and an expansion-relaxation movement of the main structure of the scar tissue in the direction parallel with the skin cleavage lines.

Cicatrix↗
PubMed1982

Photolysis of pyridinoline, a cross-linking amino acid of collagen, by ultraviolet light.

Pyridinoline, a cross-linking amino acid of collagen, was degraded by irradiation of ultraviolet light. The decomposition rate varied with pH of the solution and wavelength of irradiation light. The maximum of the degradation rate at individual pH coincides with the ultraviolet absorption maximum. Namely, it was maximally degraded by irradiation at 295 nm in acidic solution and at 325 nm in neutral and alkaline solution. At the optimum wavelength, the photolysis occurred more rapidly in neutral and alkaline solution than in acidic solution. The quantum yield in neutral solution was approximately 0.11 and independent of wavelength. One of the photolysis products was identified as hydroxylysine on an amino acid analyser, indicating that the cleavage of the pyridinium ring occurred.

Amino Acids↗
PubMed1982

[Timed bacteriostatic and bactericidal activities of cefmetazole against selected gram-negative bacteria].

Antibacterial activities of cefmetazole, a new preparation of cephamycin antibiotic, were determined against selected clinical strains of Escherichia coli (27 strains), Klebsiella sp. (27 strains) and Bacteroides fragilis (27 strains). Activities were evaluated at bacteriostatic and also bactericidal levels with particular reference to time of exposure of microbes to the drug. The minimal drug concentrations producing minimal reduction of colony-forming units at time intervals of 3, 6 and 24 hours after exposure to the drug--approximations to the theoretical bacteriostatic concentrations--were designated as 3-h, 6-h and 24-h MRCs, respectively. Conventional MIC yielding no turbidity after incubation of antibiotic-containing broth for 24 hours was also determined. The minimal concentrations of the drug producing 99.9% killing at time intervals of 3, 6 and 24 hours after exposure to the drug were designated as 3-h, 6-h and 24-h MLCs, respectively. Assuming that the apparent mode of action of a drug is bactericidal when the ratio of bactericidal-bacteriostatic concentrations is low (less than or equal to 4) and bacteriostatic when high (greater than or equal to 8), then cefmetazole appeared to be a bactericidal drug to a considerable number of Gram-negative strains when the exposure time exceeded a period of 6 hours. The data that the mode of action of this drug is bactericidal with such relatively brief exposure times--indicating rapid decrease of colony-forming units--would suggest cefmetazole is an excellent antibacterial agent and would be a useful drug in treatment of bacterial infections.

Anti-Bacterial Agents↗
PubMed1977

Postoperative scars and cleavage lines.

We elucidated the pattern of skin cleavage lines of the neck of Japanese cadavers and studied the scarring in 42 cases of radical neck dissection for the removal of metastatic nodules from the malignant tumors of the oral region, in the operation of which one incision was made parallel to, and another perpendicular to, the cleavage lines. From this study we came to the following conclusions: 1) The cleavage lines run parallel in ring-form around the neck, with the exception of the back and the lowermost part of the base of the neck. Seen from the side, the lines run horizontally across the neck. 2) Raised and widened scars were few at the site of the incision parallel to the cleavage lines but there were seen often at the site of the perpendicular incision. 3) There were no raised postoperative scars in the patients who had received radiotherapy prior to the time of observation.

Adult↗
PubMed1976

Cleavage lines in the facial skin of Japanese cadavers.

Since Langer published his work on the cleavage lines of the skin in 1861, many Japanese and foreign authors have referred to Langer's lines as the most appropriate guides for skin incisions giving minimum scarring after heelings, but it has recently been suggested that the cleavage lines of Langer do not constitute a suitable guide for making an incision. Furthermore, comparison with directions of the lines described in the published textbooks has shown some discrepancies in detail among these descriptions, especially in the face. Therefore, Japanese cleavage lines were examined in the facial region of seven male and four female Japanese cadavers, and the following results were obtained. 1) Forehead: The long axes of the cleavage lines tend to run transversely as a whole. 2) Eyelids: The lines run, drawing a concentric loops, aroung the eye-fissures. 3) Lips: The main direction of the lines on the upper lip is radial upwardly, and the lines radiate downward on the lower lip.

Cadaver↗