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Biomedical subjects

M Toyoda

Publications and source records attributed to M Toyoda.

At least 217 records · Page 12Linked to original sources

Prosthetic management of postsurgical fistulas in patients with cleft lip and palate.

A prosthesis devised for a young adult patient with a remaining cleft is described. This prosthesis would be effective for similar patients because it has the advantages of both fixed and removable partial dentures, a design acceptable to the patient, better hygiene because of easy insertion and removal, simple construction, and a moderate cost.

Adult↗

Differential hypersensitivity of xeroderma pigmentosum lymphoblastoid cell lines to ultraviolet light mutagenesis.

Survival and mutation after u.v. light irradiation were examined in four human lymphoblastoid cell lines; one cell line with normal excision-repair capacity (HH4), two excision-repair-deficient xeroderma pigmentosum (XP) cell lines from patient XP3BE (complementation group C) and XP7NI (group A), and one cell line from an XP heterozygote (XPF7NI, father of XP7NI). Relative to HH4 and XPF7NI, both XP3BE and XP7NI were more sensitive to the cytotoxic effect of u.v. by virtue of a diminished shoulder and a steeper slope in the survival curve determined by growth curve extrapolations. The mutagenesis for 6-thioguanine resistance (TGr) was measured by the limiting dilution technique using 96 well microtiter plates. Even at non-cytotoxic fluences, u.v. light induced TGr mutations in HH4 and XPF7NI with no apparent threshold, and the mutagenic response of XPF7NI was no different than that of HH4. Both XP cell lines were more sensitive than normal cells to u.v.-induced mutation. However, XP7NI cells were extremely hypermutable by u.v.; i.e. 3.3 J/m2 induced an approximately 500-fold increase of mutant fraction with the background of 2 X 10(-6). XP7NI cells remained much more mutable by u.v. even when plotted against survival, whereas the mutant fractions for XP3BE and HH4 followed the same line. These results imply that the mechanism of u.v.-induced mutation in XP7NI cells may intrinsically be different from that in XP3BE, XP heterozygote or normal cells, or that potentially mutagenic lesions are repaired much less efficiently in XP7NI cells than are potentially lethal lesions, as compared with XP3BE, XPF7NI and HH4 cells.

Cell Line↗

A simple ion--chromatographic method for determination of urinary oxalate.

A simple and rapid technique for the determination of oxalate in urine by ion chromatography has been described. Although there is difficulty in separating the oxalate peak from the sulfate peak on the conductivity chromatogram of unprocessed urine, it is possible to eliminate the sulfate peak by the addition of barium chloride to the urine. Using this technique, the author has estimated the urinary oxalate in 33 urolithiasis patients and in 40 non-urolithiasis patients. The means of 50 urinary oxalate determinations in 33 urolithiasis patients and of 42 urinary oxalate determinations in 40 non-urolithiasis patients were 21.5 +/- 11.4 and 19.5 +/- 13.0 mg/gCr, respectively. Of the 33 urolithiasis patients, 17 were calcium stone formers and 6 were non-calcium stone formers whose stones had been analyzed by infrared spectrometry, and the mean urinary oxalate values were 19.4 +/- 6.9 and 21.3 +/- 8.2 mg/gCr, respectively. The urinary oxalate was significantly higher in children under the age of 10 years.

Adolescent↗

[Body movements during sleep in Lennox syndrome].

In Lennox syndrome the brainstem which plays important roles in regulating sleep and its parameters is thought to be disturbed. In order to clarify the importance of the dysfunction of the brainstem in Lennox syndrome, polygraphic examination were studied and their findings were assessed with prognosis. 8 patients aged from 6 to 17 years were subjected to this study. They were divided into two groups according to their prognosis. Group 1 showed good prognosis. Seizures were easily controllable and have not occurred for more than 24 months. In group 2 seizures were intractable and were uncontrollable by medication. In 4 normal children ranging in age from 4 to 10 years, the same studies were performed. Recordings were performed on two consecutive nights and the second night recordings were used for analysis. Polygraph consisted of EEG from C4 and P4, bipolar EOG from electrode attached to outer canthus, surface EMG from submental muscle and 5 or 6 other muscles including trunk and limbs. Sleep stages were determined in each minute according to the standard of APSS. Body movements were classified into two types on the basis of their distribution over body parts and on duration of movements. Gross movements (GM) involved the body trunk and lasted for more than two seconds. Twitch movements (TM) were localized in one muscle on surface EMG recordings lasting less than 0.5 seconds. In normal children, the rate of GM in sleep stage 1 and REM are significantly higher than slow wave sleep. And this is the same in TM of all muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗