Histological structure of vocal fold lamina propria in foetal larynx

Previous investigations of vocal fold lamina propria in adult human larynx have revealed a highly specific organization and distribution of the connective fibres. The authors tried to elicit the developmental characteristics of that process using a material of foetal larynxes, ranging in foetal age from 13 to 23 weeks. The specimens were embedded in paraffin and then serially sectioned in both horizontal and vertical plane. The specific technique of differentiating elastic fibres from collagen fibres was utilized. The distribution and organization of connective tissue in foetal vocal fold lamina propria differed from that in adults and no straight elastic fibres were demonstrated as the first sign of later differentiation.

[Organotypic culture of normal and neoplastic laryngeal mucosa]

Mucous membrane's phragments from human normal and neoplastic larynx have been maintained in a organ culture system. A set of cultures has been prepared for optical microscope studies and a parallel set for incorporation studies using 3H Thymidine and 3H Leucine. The results show that there is a good incorporation of 3H Thymidine and a greater incorporation of 3H Leucine at the 7th day due to a differentiation in vitro with a new synthesis of cheratin. These data agree with the morphologic evidence of considerable horny structures in the pathological mucous membrane after 11 days at culture.

Cytoarchitectonic organization of laryngeal motoneurons within the nucleus ambiguus of the cat

The central distribution of laryngeal motoneurons was studied in the cat by retrograde axonal transport of horseradish peroxidase. The enzyme was injected selectively into the cricothyroid (CT), lateral cricoarytenoid and thyroarytenoid (LCA-TA), and posterior cricoarytenoid (PCA) muscles of the larynx with or without the previous sectioning of the left laryngeal recurrent nerve (LR) or the left superior laryngeal nerve (SL). The CT motoneurons appeared as a compact group of medium-size cells located in the rostral one-third of the nucleus ambiguus (nA). The LCA-TA motoneurons were found in the caudal two-thirds of the nA, constituting a loose group of large motoneurons. The PCA motoneurons were located throughout the whole extend of the nA, the cells being large in the caudal pole and smaller in the rostral one-third of nA. Laryngeal muscle innervation was exclusively of ipsilateral origin. Axonal projections in the brain stem were different depending on the nerve (LR or SL) by which the efferent fibers were sent.

Age-related changes in the epithelium of the monkey larynx

An experiment was designed to measure the area of subglottic squamous epithelium in a group of 14 adult monkeys. The animals were much older than any so far available for medical research. The larynges were strained using pyronin Y, which stains respiratory epithelium magenta and squamous epithelium pale pink. The areas of squamous epithelium inferior to the free margin of the vocal cord were measured. The results showed that the subglottic epithelium increased with age (r = +0.61, p = less than 0.05). This finding may have importance in the staging of laryngeal carcinoma.

The size of motor units in laryngeal muscles of the rat

The size of motor units in rat laryngeal muscles was determined by correlating the number of neurons labeled by i.m. injections of horseradish peroxidase with the number of motor end plates stained for acetylcholinesterase. The cricothyroid has a motor unit size of 8 muscle fibers per motor neuron and the posterior cricoarytenoid 4-5 muscle fibers per motor neuron.

Mitotic indices of rat laryngeal epithelia

The histology and mitotic indices of rat laryngeal epithelia were investigated. Five distinct types of epithelia were found: stratified squamous, squamoid (low squamous), respiratory and two cuboidal forms. Squamous epithelium was present mainly in the cranial portion of the larynx, whereas the respiratory type was mostly located in caudal regions. One type of cuboidal epithelium often formed intermediate zones between squamous and respiratory areas. Another form of cuboidal epithelium lined the ventral pouch, and the vocal folds were covered by a low squamous or squamoid type. The mitotic index for each type of epithelium was calculated using colchicine and was expressed as the percentage of total epithelial cells of that kind in mitosis. Mitotic indices for laryngeal epithelial types were: 5.6% in squamous epithelium; 2.4% in the squamoid epithelium of the vocal folds; 2.2% in the cuboidal epithelium in the ventrolateral region; 1.5% in the cuboidal epithelium of the ventral pouch, and 0.6% in respiratory epithelium, although in isolated ciliated areas in the lower epiglottis it was considerably higher (2.6%). There were no significant differences between rats examined on different occasions.

[The determination of the earliest signs of cell damage after translaryngeal intratracheal long-term intubation in rabbits. A light- and electron-microscopic study]

Eighteen New Zealand rabbits were artificially respired, orotracheally with a cuff pressure of approximately 35 mm Hg, for between 2 and 36 h. After 2 h artificial respiration cell degeneration was seen in the area of the cuff, above the cartilage rings, in the form of cytoplasmic degeneration. After a 4 h intubation period an epithelial loss was seen. The basal membrane was intact. A connective tissue oedema, which was limited to the region of the epithelial lesion, became more wide-spread over the 36 h of intubation. A well-developed ulcer could be identified under the light microscope after 36 h. Increased mucous production as well as an increase in bacteria could be observed after 4 h. At no time could a degeneration of the cartilage be seen in the electron micrographs. The intercartilaginous area also remained free from cell degeneration although signs of vascular congestion could be seen.

Immunopathological study of the larynx. IgA distribution and secretory activity

Using immunofluorescent and histopathological techniques, we studied the distribution and secretory activity of the glands of the larynx from 55 humans. The cavity of the larynx was covered with secretory glandular cells with the exception of the true vocal cords, aryepiglottic folds and upper part of the laryngeal surface of the epiglottis. Immunofluorescent study revealed the presence of IgG and other immunoglobulins throughout the connective tissue ground in each laryngeal mucosa. The most striking was seen in the staining pattern of IgA. Diffuse fluorescence for IgA was observed not only in the submucosal or periglandular connective tissue area but also in the intraeptithelial or submucosa glands. Secretory component synthesis was found mainly in each serous-type glandular epithelium or acinus. In the submucosa or periglandular area, IgA producing plasma cells were numerous. Our observations suggest that IgA, produced locally, is secreted via the glandular cells as secretory component--SIgA. Secretory activity of SIgA in these glandular tissues indicates that the larynx is possibly an immunologically active organ in the upper respiratory tract.

[Cytology of the early invasive laryngeal cancer (author's transl)]

In order to obtain accuracy in the detection of the pre-invasive and early invasive laryngeal cancer microscopy and cytology can be jointly used. The cytologic picture of the early invasive laryngeal cancer is described including its precursors.

[Preliminary observations on the ultrastructure of the human laryngeal glands: the secreting cells]

The secretory portions of human laryngeal glands consist of seromucous and mucous cells. Seromucous cells contain granules either homogeneously dense or endowed with a bipartite structure, consisting of a clear peripheral halo and a central dense portion. In any case, however, they exhibit a morphological appearance different from that observed in seromucous granules of salivary glands. Mucous cells vary considerably according to the functional state.

Dual-laser flow cytometry of single mammalian cells

An improved dual-laser flow cytometric system for quantitative analysis and sorting of mammalian cells has been developed using a low-power argon and high-power krypton laser as illumination sources, thus permitting the excitation of fluorescent dyes having absorption regions ranging from the ultraviolet to infrared. Cells stained in liquid suspension with fluorescent dyes enter a flow chamber where they intersect two spatially separated laser beams. Separate pairs of quartz beam-shaping optics focus each beam onto the cell stream. Electro-optical sensors measure fluorescence and light scatter signals from cells that are processed electronically and displayed as frequency distribution histograms. Cells also can be electronically separated and microscopically identified. The ease and versatility of operation designed into this system represent a marked technological improvement for dual-laser excited flow systems. Details of this instrument are described along with illustrative examples of cells stained with mithramycin and rhodamine and analyzed for DNA content, total protein, and nuclear and cytoplasmic diameter.

Histologic and biochemical identification and characterization of an elastin in cartilage

Histochemical and chemical techniques have been used to identify, isolate and characterize elastin from certain bovine cartilages. The results strongly suggest that in addition to fibroblasts and smooth muscle cells, chondroblasts also synthesize elastin. Some of the possible functions of elastin in elastic cartilages are discussed and the possiblity of a new type of elastin perhaps unique to cartilage is suggested.

Argyrophilic cells in the larynx of the guinea-pig demonstrated by the method of Grimelius

Argyrophilic cells with branching processes are shown in both the surface epithelium and in the glands in the larynx of adult guinea-pigs using the Grimelius silver technique after GPA fixation. When Bouin's fixative or neutral formalin were used as fixatives argrophilic cells could not be identified.

A long-term comparative study of the mammalian larynx, based on whole organ serial sectioning

The paper includes brief details of a long term three-dimensional study into the fine structure of the mammalian larynx using whole organ serial sections. Differential staining, including Glees silver technique, is essential if maximum information is to be gained. A specially designed punch card will enable any future investigator to rapidly retrieve relevant information and it is expected that specimens of all available mammalian larynges will be included. Illustrations are included in this paper of the cat, dog, horse and mongoose.

An improved method for staining cells of the endocrine polypeptide (APUD) series by masked metachromasia: application of the principle of 'fixation by excluded volume'

Masked metachromasia is demonstrated by staining with a metachromatic basic dye, after acid hydrolysis of suitably fixed tissue. We report that the addition of 20% Carbowax 20M (an inert polyer, mol. wt. about 20,000) to the hydrolysis mixture improved the reaction. The improved method gives increased metachromasia , greater tolerance to variations in hydrolysis conditions, and demonstrates a greater proportion of cells--presumably due to a lower threshold of sensitivity. Lower molecular weight polymers (Carbowax 1000, Carbowax 6000) are less effective.

Dendritic pigmented cells within human laryngeal mucosa

Melanocytes were seen within the basal layer of the laryngeal squamous epithelium in a biopsy specimen of the vocal cord. No dendritic pigmented cells were visualized in several sections of the entire mucosa of 15 autopsy specimens of the larynx, but clear, Langerhans-like cells were seen, suggesting that melanocytes in this location may possibly become effete. This may account for the infrequent occurrence of primary malignant melanotic lesions of the larynx.

New observations of rat airway epithelium: a quantitative and electron microscopic study

Epithelial thickness, depth of the ciliary layer and concentration of cells has been estimated at 5 levels of the rat airway (3 extrapulmonary and 2 intrapulmonary) and the ultrastructure of the cells described. Extrapulmonary airways have a pseudostratified epithelium, intrapulmonary airways a simple one. The epithelium thins progressively from upper to lower trachea while the epithelium of the lower trachea is thicker than at more peripheral airway levels, all of which are similar. The depth of the ciliary layer decreases peripherally. By electron microscopy 10 cell types could be identified - 8 epithelial and 2 'migratory'. A cell type not described previously has been found that resembles the serous cells of the submucosal glands. The salient features of each cell type are described. The upper trachea has a concentration of cells significantly higher than elsewhere, while the remaining four airway levels have about 230 cells per 10 high power fields (1-8 mm length epithelium). Ciliated cells are sparse proximally and increase in number progressively toward the periphery, while basal and migratory cells are most frequent proximally. At all levels of the airway, between 40% and 50% of cells are non-ciliated. In the upper trachea the most frequent cell type was the 'intermediate', elsewhere the 'epithelial serous' cell. Goblet cells were few at all levels, amounting to less than 1% of the total counted. The Clara cell was not restricted to the terminal bronchioles but was found as far proximally as the hilum.

An alcian blue-phloxine method for the gross demonstration of squamous metaplasia in the larynx

A macroscopic method using the dyes Alcian blue and phloxine is described for the investigation of squamous metaplasia in the larynx. The method also demonstrates an intermediate type epithelium about which little is known. The gross staining of the tissues is based upon the differential penetration of the dyes through squamous, intermediate and respiratory epithelia, and on the strong chemical complex formed between Alcian blue and mucin. The method is particularly useful for research purposes owing to the permanency of the staining result.

Intra-epithelial nerves in normal rat airways: a quantitative electron microscopic study

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