Ultrastructural Detection of Nitric Oxide in Human Nasal Mucosa

OBJECTIVE: Nasal vasculature and seromucous glands are exposed to complex mechanisms influenced by external as well as internal stimuli. In addition to classic and peptidergic neurotransmitters, nitric oxide (NO) was increasingly found to be important in the control of various physiologic functions. NO modulates nasal immunology, influences macrophage activity, and has antiviral and bacteriostatic properties. The aim of this study was to show the localization of nitric oxide synthases (NOS) I and III in the normal human nasal mucosa by using immunoelectron microscopical techniques. STUDY DESIGN: Specimens of noninflammed inferior turbinates from 35 patients who underwent nasal surgery were fixed in phosphate-buffered glutaraldehyde. After dehydration, incubation in unicryl and polymerization, ultrathin sections were cut. Primary antibodies against NOS I and III were applied and the immunocomplexes were visualized by an immunocytochemical staining-technique using gold-labeled antibodies. Immunostained structures were photodocumented using a transmission electron microscope. RESULTS: NOS-immunoreactive nerve fibers were mainly co-located in parasympathetic nerves in the adventitia of arterial vessels and in periglandular axons. Electron microscopy showed that NOS-positive axons were in close contact with acinus cells. A strong NOS III-immunoreactivity was found in endothelial cells of capillaries near the glands as well as in arterial vessels. Furthermore, immunoreaction products were deposited throughout the cytoplasm of fibroblasts. CONCLUSION: Nitric oxide in nerve fibers, seromucous glands, and endothelial cells of capillaries and arterial vessels suggest that NO takes part in the regulation of physiologic processes of the human nasal mucosa. NOS was co-localized in para-sympathetic nerves and plays a role in the neurotransmission and neuromodulation of the vascular tone and glandular secretion. Arteries showed a distinctly developed nitrergic innervation and endothelial accumulation. The NO production in axons of the adventitia and in the endothelium of arteries demonstrated that these vessels are influenced by a dual NO system. NO could mainly act on these structures with vasodilatatory effects. Finally, NO would be able to influence the functions of perivascular fibroblasts.

Regulation of vocal fold transepithelial water fluxes

Vocal fold hydration is critical to phonation. We hypothesized that the vocal fold generates bidirectional water fluxes, which are regulated by activity of the Na+-K+- ATPase. Western blots and immunohistochemistry demonstrated the presence of the α-subunit Na+-K+-ATPase in the canine vocal fold ( n = 11). Luminal cells, basal and adjacent one to two layers of suprabasal cells within stratified squamous epithelium, were immunopositive, as well as basolateral membranes of submucosal seromucous glands underlying transitional epithelia. Canine ( n = 6) and ovine ( n = 14) vocal fold mucosae exhibited transepithelial potential differences of 8.1 ± 2.8 and 9.3 ± 1.3 mV (lumen negative), respectively. The potential difference and short-circuit current (ovine = 31 ± 4 μA/cm2; canine = 41 ± 10 μA/cm2) were substantially reduced by luminal administration of 75 μM acetylstrophanthidin ( P < 0.05). Ovine ( n = 7) transepithelial water fluxes decreased from 5.1 ± 0.3 to 4.3 ± 0.3 μl · min−1 · cm−2 from the basal to luminal chamber and from 5.2 ± 0.2 to 3.9 ± 0.3 μl · min−1 · cm−2 from the luminal to basal chamber by luminal acetylstrophanthidin ( P < 0.05). The presence of the Na+-K+-ATPase in the vocal fold epithelium and the electrolyte transport derived from its activity provide the intrinsic mechanisms to regulate cell volume as well as vocal fold hydration.

Pathology Consultation Nonsquamous Carcinomas of the Larynx

Nonsquamous carcinomas make up fewer than 1 % of all epithelial malignancies of the larynx. The majority are subsurface in origin and arise from seromucous glands of the larynx. Adenoid cystic carcinoma is not only representative of this group, it is the most prevalent. All other salivary-type carcinomas are rare. Rarer still are surface adenocarcinomas. Neuroendocrine carcinomas appear to constitute the majority of so-called laryngeal adenocarcinomas.

Clear Cell Carcinoma of the Larynx: Immunocytochemical Study

A case of clear cell carcinoma of the larynx with multiple metastases is reported. The histological and immunohistochemical characteristics of this tumor are discussed as well as the main differential diagnoses. An origin from seromucous glands of the larynx is proposed. A literature review showed that clear cell carcinoma of the larynx is rare and is characterized by extremely high aggressiveness.