Mutations and polymorphisms in mitochondrial DNA in head and neck cancer cell lines.

Changes in mitochondrial DNA have been reported in cancer cells. Since little information exists regarding mt DNA mutations in head and neck, the present study focused on ten head and neck cancer cell lines in the attempt to detect alterations in the ND4 gene sequence. DNA was extracted from 10 head and neck squamous cell carcinoma lines from 9 patients. MtDNA sequences were compared in normal and tumour cell line DNA. In ten head and neck squamous cell carcinoma cell lines, 8 somatic mutations and 5 polymorphisms of the mitochondrial gene for ND4 were found. All 5 polymorphisms were silent. Of the 8 somatic mutations, 3 altered the amino acid sequence suggesting a possible effect on enzyme function. The mitochondrial mutations and polymorphisms found demonstrated that these can serve as clonal markers for individual cell lines and demonstrate that the mitochondrial genome remains stable in the cell lines during in vitro culture.

[CO2 laser cordectomy: analysis of morpho-functional results]. / Analisi morfo-funzionale degli esiti chirurgici nei diversi tipi di cordectomia con laser a CO2.

The authors have conducted a study of a large sampling of subjects who had undergone different types of cordectomy. The purpose of this study has been to analyze the anatomo-functional variables encountered with such procedures. In particular, the following were studied: post-surgical vocal recovery; type of glottic sphincter scarring, particularly as related to the extent of surgical excision; effect commissure synecchia has on the post-operative voice, again related to type of exeresis; different types of functional compensation related to the various surgical excisions and means by which the new scarring cord is built; severity of dysphonia resulting after each type of surgery. The study involved 69 patients who had undergone different types of cordectomy: from limited procedures--the so-called submucosal cordectomies for circumscribed, superficial neoplasms--to more radical ones, performed on tumours extending to the laryngeal ventricle of one or both sides. A history was taken of all the cases and they underwent videolaryngoscopy, psychoacoustic evaluation and voice spectrography. This study revealed the following: vocal recovery is achieved within 1-3 months after surgery, particularly when the exeresis was limited; longer recovery times were required for more radical surgery; with horizontal exeresis the prognosis for sphincteric recovery--characterized by a good neocord--is better than with procedures removing structures on the vertical plane (true vocal cord + ventricle + false cord) where scarring generally proves inadequate to re-establish a satisfactory sphincter; commissure synecchia is unusual in all types of surgery and is more frequent in bilateral forms. This is not specifically responsible for aggravating the dysphonia although, except in a few cases, it can make an important contribution in limiting the glottic opening and facilitating vocal sounds; as regards functional compensation, the observations show that the larynx is able to adapt to anatomic damage, the entire organ playing a part in reducing the air space to create a more or less valid phonatory sphincter, each part in its own way. Among the most noteworthy mechanisms for functional compensation we find the cord-neocord, the glottic mechanism at the false cords and ary-arythenoid compensation. There is no direct relationship between phonatory mode and neocord conformation since not all cases achieving a satisfactory neocord actually use glottic phonation. Although the Yanagihara spectrographic classification of dysphonia cannot distinguish between severe dysphonia and aphonia, it can be applied in the objective classification of limited post-cordectomy vocal compromise. In fact, spectrography is able to document that: Type II dysphonia--light--is unusual and was only found in 2 cases with a excellent neocord and a perfect pneumo-phonic picture; Type II dysphonia--moderate--is most often found in submucosal cordectomies and in other cases of monolateral exeresis with adequate scarring; Type IV dysphonia actually corresponds to the most important forms. It is present in all types of cordectomy and is most prevalent in those with a severe adductor deficit associated with inadequate or poorly balanced supraglottic functional compensation.

[Anatomo-functional study of 37 patients with monolateral chord paralysis]. / Studio anatomo-funzionale su 37 pazienti affetti da paralisi cordale monolaterale.

The authors present a study of 37 patients affected by monolateral vocal cord paralysis in order to analyze etiology, degree of dysphonia and possible recovery of vocal function. The patients underwent the following tests: case history to determine the vocal characteristics prior to the lesion; video-laryngoscopy to define the position of the paralytic cord on the horizontal glottic plane and any compensation mechanisms; determination of the degree of dysphonia (light, moderate, severe, aphonia) on the basis of psycho-perceptive parameters; spectrography evaluated in classes (I, II, III and IV) according to Yanagihara. Analysis of the data obtained makes it possible to draw the following conclusions: the most frequent etiology encountered by the otorhinolaryngologist is surgical (particularly subsequent to thyroidectomy); the position taken by the paralytic vocal cord does not appear to determine the degree of dysphonia; during the period immediately after occurrence of the lesion (0-4 months) the vocal disorder is more intense and tends to be reduced thereafter, attenuated by a spontaneous compensation mechanism. In this regard, it must be pointed out, however, that such compensation can prove bad or even dangerous for good vocal function (falsetto voice); speech therapy makes it possible to nearly totally normalize vocal function in all patients presenting moderate dysphonia and in 60% of those with severe dysphonia. In the remaining 40% of those patients with severe dysphonia a partial improvement of vocal function was seen (from severe dysphonia to moderate dysphonia). This was determined by the fact that several negative prognostic factors came into play simultaneously in these patients (i.e. advanced age, longer time gap since the lesion occurred, position assumed by the paralytic cord) which prevented them from achieving better phonatory results.

CO2 laser in laryngeal microsurgery.

The CO2 Laser is used in the treatment of several laryngeal diseases and offers considerable advantages over traditional techniques. New applications of this surgical tool are currently under study for other laryngeal and ENT pathologies. It should be pointed out that there are some limitations to the use of the CO2 Laser; an accurate examination of its indications is needed, as well as a precise knowledge of its techniques and possibilities.