It is generally considered that phonation is mainly controlled by two factors, i.e., the driving force and the laryngeal adjustment. Many aerodynamic studies on phonation control have been conducted. However, only the mean value of air flow and subglottal pressure were measured and reported in these studies. The airflow at the lips, the subglottal pressure, the supraglottal pressure, and the electromyograms of the thyroarytenoid (TA) and the cricothyroid (CT) muscles were simultaneously recorded in the present study. The waveforms of glottal airflow, transglottal pressure, and glottal resistance were extracted from the airflow and the pressure signals. The precise mechanism of phonation control was investigated using these signals. In case of high pitch phonation, the intensity of voice was found to be controlled mainly by driving force. On the contrary, the intensity was controlled mainly by laryngeal adjustment in case of low pitch phonation.

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A method of estimating subglottal pressure through intraoral pressure has been reported in the literature. In order to determine its utility in the clinical field, however, the method should be tested against direct measurement made on subjects with pathologic larynges. The present study was designed to compare intraoral pressure against subglottal pressure as measured with a sensing tube inserted through a tracheal stoma. Results showed that peak intraoral pressure of /i:pi:/ was smaller than subglottal pressure when the former showed the values larger than about 20 cm H₂O. We concluded that the magnitude of subglottal pressure did not always be represented by peak intraoral pressure of /p/ production. This conclusion, however, does not harm the usefulness of this method of estimation, since the estimation of subglottal pressure would be required when we want to know if the subglottal pressure is within the normal range, rather than when high subglottal pressure is easily presumed with other clinical symtopms.

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We have analyzed the dynamic movement of vocal folds during phonation by using the digital fluorography (DF) system. In this paper, the movements of vocal initiation at modal register phonation and at vocal fry phonation were analyzed through the subtracted images offered by DF. As the subtraction technique, time interval difference (TID) mode with two frames was performed on the images obtained at the rate of 30 frames per second.
The results were the followings : in vocal fry phonation, 1) the thickening of the vocal folds downward was observed soon after their adduction finished, 2) the enlargement of the subglottal space due to the increase of subglottal pressure after adduction of vocal folds was smaller than that in modal register phonation, 3) the true and the false vocal folds adducted more strongly than that in modal register phonation, ) the time interval from the beginning of vocal folds adduction to the beginning of phonation was longer than that in modal register phonation.

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A pair of stainless steel electrodes were directly attached to the right internal branch of the superior laryngeal nerve (SLN) of a patient, on an occasion of total laryngectomy under general anesthesia. Square-wave electric stimuli were applied to the SLN, and the evoked electro-myographic signal (EMG) was picked up from the left cricothyroid muscle with a hooked-wire electrode. The larynx-evoked brain stem response (LBR) was also recorded via surface electrodes attached the skin of the head.
These evoked signals were averaged with a signal averaging computer. A two-phasic evoked EMG waveform was obtained with a latency of about 18 msec. An LBR wave with 3 positive peaks and 4 negative peaks was invariably derived corresponding to the stimuli, with a latency of about 3.5 msec. These data apparently demonstrated the existence of LBR in man.
Based on these findings, a clinically applicable method of obtaining LBR signal was devised. A hooked-wire electrode for stimulation was placed percutaneously in the vicinity of the SLN in 9 normal subjects. The cricothyroid EMG was recorded with another hooked-wire electrode. The position of the stimulating electrode was adjusted by monitoring the evoked EMG waveform on the CRT screen. The LBR signal was recorded via the surface electrodes. A similar LBR waveform as stated above was obtained. The clinical importance of recording LBR was emphasized.

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Seven laryngeal polyps surgically removed from 7 adult patients were examined immunohistochemically to identify presence of the following substances : keratin, transferrin, lactoferrin, fibrinogen, vimentin, factor VIII, EMA (Epithelial Membrane Antigen) and S-100 protein.
There was a considerable amount of keratin and EMA in the atrophied stratified squamous epithelial cells.
Vimentin was present in a large size of mesenchymal cells, which were distributed in the subepithelial tissues of fibrous polyps.
A great amount of transferrin, fibrinogen and factor VIII was noted in the subepithelial tissue of the polyps, primarily of the edematous and/or hematomatous types. Since these substances are serum protein, this suggests that they were delived from serum due to increased vascular permeability.
Immunostaining for S-100 protein revealed no nerve fibers in the laryngeal polyps.
It is concluded from the present observation that laryngeal polyps are formed by a subepithelial retention of the blood constituents due to local vascular disturbances.

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In order to determine the etiological factors and clinical caracteristics of the polipoid vocal cord, seventy-four patients, who had had laryngomicrosurgery in our hospital between 1979 and 1988, were studied retrospectively. There were not sexual difference in outbreak of the polipoid vocal cord. Over 70% of patients were those of 40 years old or more. Sixty-eight patients showed that pathological change of their vocal cord were observed in both side. 70 % of patients visited our hospital after one year or more since they noticed hoarseness as a initial symptom. Because of smoking history revealed in high percentage, the smoking should be considered that was most effecective etiological factor of the polipoid vocal cord. 69 patients out of 74, told that they had enjoyed smoking 20 or more cigarettes per day over 30 years. It was speculated that there was a close relation between the outbreak of polipoid vocal cord and increased cigarettes and a period of smoking. In Brinkman's index which was used for determination of the relation between lung cancer and smoking, most patients showed less than 1500. Occupational vocal abuse was found in the history of thirty-six patients out of 74. From these clinical findings, it might be concluded that the onset and aggravation of polipoid vocal cord were close related to chronic irritation like as smoking or vocal abuse.

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This study reports on the follow-up carried out on 69 cases of Reinke's edema treated by the squeezing technique proposed by the authors' group during the period from 1985 to 1989. The results were as follows : (1) In 40 out of 69 cases (58.0%), a small open wound on the vocal folds remained immediately after surgery, while in 29 cases (42.0%) there was a large wound. According to the authors' classification, the incidence of cases with a large wound was significantly higher in Type III than in Type I and II. (2) In 54 out of 59 cases (91.5%) normal vocal fold vibration was recovered within 6 months after surgery, while the remaining 5 did not show any signs of recovery within one year after surgery. Those patients who had a small open wound of the vocal folds and stopped smoking after surgery recovered rapidly. Among the Type Ill cases the recovery period tended to be prolonged. (3) The length of time until the speaking voice could maintain stability did not exceed 8 months after surgery in almost all cases and was prolonged more than 4 months in Type III cases. (4) The incidence of recurrent edema of the vocal folds was significantly greater in patients who continued to smoke after surgery than in those who stopped smoking. (5) Most cases reported subjective satisfaction for resulting from the treatment after surgery. On the other hand, some of the Type I and II cases complained that the voice after surgery was not improved sufficiently to meet occupational needs.

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Intracordal injection of the synthesized material such as silastic or teflon to the paralyzed vocal cord has been performed to improve the voice quality. Recently, collagen has been also utilized as the injection material. Although silastic is stable in the tissue and causes no apparent biological reaction, it is rather difficult to control the reaction time for polymerization. On the other hand, collagen is easy to prepare and manipulate but has a risk to cause allergic reaction.
Recently, we have been using a newly developed material of room temperature vulcanized (RTV) silastic and which provides consistent reaction time for polymerization and stability in the tissue.
Animal experiments proved safety and stability of the new material in the tissue.
Results of the animal experiments and clinical applications were reported in this paper.

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For detecting human papillomavirus (HPV) genomes in laryngeal papillomas, we examined the applicability of Southern light^TM and Viratype^TMin situ methods, and compared with digoxigenin (DIG) -labeled probe.
We examined 8 cases of paraffin embedded tissues by in situ hybridization (ISH), and 2 cases of fresh frozen tissues by dot blot and Southern blot hybridization.
By ISH with DIG-labeled probe, we could detect HPV type 6 or HPV type 11 in 6 cases (75 %). By ISH with Viratype in situ which used biotin (BIO) -labeled probe, we could detect HPV 6/11 in 5 cases (62.5%). Thus, DIG-labeled probe was more sensitive than BIO-labeled one.
By Southern light method which used a direct chemiluminescent substrate (AMPPD), we could detect HPV 11 in the 2 cases examined. Southern light method turned out to be a sensitive and rapid detection system for dot blot and Southern blot hybridization.

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[in Japanese]

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The Yokohama Municipal Cancer Detection Center, established as an affiliate of the Yokohama Municipal Citizen's Hospital in June, 1981, performed examinations for larygeal cancer on a total of 13,324 people over the age of 40 in the 8 years and 6 months between its founding and December, 1989. Males and females were represented in approximately equal numbers.
Of the total number of those examined. 34% presented some form of symptom in the resion of the larynx or of the head and neck; approximately 1,400 (11%) of these required further testing, therapy, or observation. 23 cases of malignant tumor were found, 20 of laryngeal cancer, 2 of thyroid cancer, and 1 of hypopharyngeal cancer. In addition, 49 cases of vocal fold leukoplakia and approximately 900 cases of such conditions as vocal fold polyp and polypoid vocal fold were diagnosed. As indicated by these results, examinations of this type possess both definite benefits and deficiencies. Examples of the latter are the small absolute numbers of examinees and the rather heavy burden placed upon the examining doctor due to the lack of an effective indirect method of testing. Cancer examinations have proved a beneficial method of early cancer diagnosis, and should be continued in conjunction with efforts to resolve shortcomings.

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The manner of spread of supraglottic carcinoma was investigated in a series of 100 cases by means of the whole organ serial section study of surgical specimens. The characteristics of infiltrating pattern of carcinoma into the surrounding tissue along the surface of the mucosa and into the deep structures were studied. The primary sites of carcinoma were divided into 5 anatomical sites : epiglottis (29cases), epiglottis and ventricular fold (35cases), ventricular fold (27cases), aryepiglottic fold (6cases) and arytenoid region (3cases). An invasion into the preepiglottic space were observed in 76 cases. In 61 (80%) of the 76 cases the preepiglottic invasion took place through the base of the epiglottis, destroying the epiglottic cartilage partially of totally. The pyriform sinus was involved in 56 cases of the present series. In 5 (9%) of the 56 cases the mucosa of the medial wall of the pyriform sinus was destroyed. The glottis was involved in 48, the arytenoid region, in 48, the thyroid cartilage, in 9, and the anterior commissure, in 12 cases. The invasions into the glottis and arytenoid region occurred superficially, through deep structures or in both ways.

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Radiotherapy for early laryngeal cancer has already been in widespread clinical use as an established therapy. However, radiation induced cancer is possibly to be problematic as that the average life span of the patient is now prolonged. The authors have tried to apply photodynamic therapy (PDT); administration of hematoporphyrin derivative (HpD) and irradiation with low energic laser, for early laryngeal cancer and recurrent ones.
As a prliminary report, this paper describes 6 patients with vocal cord cancer undergone PDT from February 1988 to January 1989. These patients consisted of 1 case of T₁, 3 cases of Tis and 2 recurrent cases after irradiation therapy.
HpD was injected intravenously at 48-72 hours before laser irradiation, and laser was applied under general anesthesia. The basic laser dose were 200-500mW/cm² with continuous wave for 20 min for Argon-dye laser and 3-4 mJ/P (30 Hz) with pulse wave for Eximer-dye laser.
In all of 4 cases of initial treatment, the tumor has been controlled for 18 months or more. In 1 recurrent case after radiation therapy, no further relapse has occurred for 28 months after PDT. Total laryngectomy was performed on the remaining 1 patient because of the recurrence after PDT. Histological examination of the resected larynx revealed that there was necrotic tissue up to the depth of 2mm and existence of cancer cells in the deeper layer and glands.
The author's impression is that more poweful laser, more effective chemical substance with exciting wave length of 600 nm and all direction illuminator should be needed for more popular use of PDT in laryngeal cancer, although PDT is a promising treatment for vocal cord cancer.

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The effect of irradiation simultaneously combined with chemotherapy by Tegafur or Cisplatin was studied in 41 cases with laryngeal cancer, in whom glottic T1a, all of subglottic cancer and of M1 were excluded. Then, it was compaired with the result in 68 cases who had been treated by radiation therapy alone as the historical controls.
Comparison between the group of 41 cases with combination radiochemotherapy and the group of 68 controls by means of kaplan-Meier's method resulted significantly more favorable in the former than in the control in the free rate from recurrence in the cases of all, in the groups of T1 and T3, in the goups of stage 1 and stage 3, in the goup of glottic cancer and in both the survival rate and free rate from recurrence in the supraglottic cancer.
Any severe adverse reaction had not been experienced in the all cases.
Therfore, the combination radiochemotherapy by Tegafur or Cisplatin is assumed to be effective for laryngeal cancer.

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