In attempts to substantiate the possible participation of reactive oxygen species, and the significance of the xanthine oxidase system in both post-ischaemic reperfusion necrosis of the island flap and distal necrosis of the pedicle flap, and to develop new pharmacological measures for salvaging flap necrosis, a series of experiments were made using an island flap model and a random-pattern flap model in rats. The results were as follows: (1) Epoxysuccinyl derivative (E-64c), allopurinol and L-SOD salvaged post-ischaemic reperfusion necrosis of the island flaps; (2) E-64c and allopurinol did not salvage anticipated necrosis of the distal region of random flaps but L-SOD did; (3) tissue SOD activity did not reflect the fate of the island flap, but did of the distal region of the random flap. These results demonstrated a possible involvement of ROS in both post-ischaemic necrosis of island flaps and distal necrosis of random flaps. However, xanthine oxidase was significant in producing ROS only in the former.

Allopurinol↗

PubMedDate not supplied

A bilayer "artificial skin" capable of sustained release of an antibiotic.

The most frequent complication of the bilayer "artificial skin", composed of a silicone sheet and collagen sponge described in a previous paper, was infection beneath it. This paper describes a new type of "artificial skin" in which microspheres containing antibiotics were installed beneath the silicone sheet, allowing a continuous release of antibiotics.

Adult↗

PubMedDate not supplied

Clinical significance of asymmetrical vocal cord tension.

The effects of asymmetrical tension on the vibratory pattern of the vocal cords were studied in two kinds of experiments: 1) high speed motion picture photography of artificial voice production in excised canine and human larynges, and 2) computer synthesis of voice and vocal cord vibration via a theoretical model incorporating the physiological parameters required for phonation. In both approaches the asymmetrically tensed vocal cords consistently vibrated in three distinct modes which depend partly on the rest positions of the vocal cords; Type I. For rest positions at or near closure, the two cords vibrate at the same frequency with glottal closure every period, and with tense cord preceding the lax one in phase and with the line of contact moving toward the tenser cord during the closed phase. The voice produced is not hoarse; Type II. For wider rest positions glottal closure occurs irregularly, the vibrations become complex and less periodic, and the voice becomes hoarse; Type III. The glottis never closes and the vibrations become more periodic with reduced amplitude. Supplementary stroboscopic observations suggest a precedure for diagnosing tension asymmetry and the implications for surgical treatment for disorders of vocal pitch are discussed.

Animals↗

PubMedDate not supplied

Cricothyroid distance and vocal pitch. Experimental surgical study to elevate the vocal pitch.

To establish an experimental basis for surgical approximation of the anterior cricothyroid distance which aims at raising the vocal pitch, the relationship between vocal pitch and the cricothyroid distance was analyzed in voices produced with excised human larynges (four male and two female larynges). Within the framework of the experimental conditions, the following conclusions were drawn: 1) The vocal pitch expressed in semitones was almost linearly related to the cricothyroid distance, with an increase of 0.15 to 0.90 semitones per milimeter of cricothyroid approximation. 2) The rise in vocal pitch reached a plateau when the force applied to shorten the cricothyroid distance reached 30 to 50 gm.

Cricoid Cartilage↗

PubMedDate not supplied

Thyroplasty as a new phonosurgical technique.

Explore the source record for details and available documents.

Animals↗

PubMedDate not supplied

Thyroplasty type I (lateral compression) for dysphonia due to vocal cord paralysis or atrophy.

Based on the experimental results of thyroplasty, thyroplasty type I which aims at medical shifting the vocal cord was performed on 8 patients with dysphonia, 6 with vocal cord paralysis and 2 with vocal cord atrophy. The surgery was conducted on either in- or out-patient basis and local anesthesia was used. Usually, a rectangular incision was made on the thyroid cartilage at the level of the vocal cord, and the fragmemt was depressed inward. A cartilage piece taken from the opposite side was used as a wedge, if necessary, to enhance the effect of lateral compression of the vocal cord. The voice after surgery was generally satisfactory, except in one case of traumatic vocal cord paralysis. Complications such as stridor or dyspnea were nil. As surgical intervention inside the thyroid cartilage is minimal, fine and reliable adjustment of depression is possible during the surgery.

Adolescent↗

PubMedDate not supplied

Computer analysis of hoarseness.

The harmonic components in hoarse voice were separated from the noise components by using a small laboratory computer. The ratio of harmonics to noise or S/N ratio, was calculated and compared with the auditory impression for 58 subjects. The calculated results showed a definite correlation to the auditory impression, and it is suggested that this would be a useful method for the quantitative evaluation of hoarseness.

Computers↗