Nitric oxide mediates platelet activating factor-induced microvascular leakage in rat airways.

Platelet activating factor (PAF), a highly potent chemical mediator in inflammation and allergic reactions, induces microvascular leakage in several tissues. In rat airways, PAF-induced microvascular leakage is probably mediated by an endothelial cell receptor in the microvessels. Nitric oxide (NO), first identified as endothelium-derived relaxing factor, has been suggested to be a mediator of airway microvascular leakage. However, the role of NO in PAF-induced microvascular leakage in the airways has not yet been established. The aim of this study was to investigate the role of NO in PAF-induced microvascular leakage in rat nasal mucosa and trachea. We injected PAF (1 microg/kg) intravenously, and the amount of PAF-induced microvascular leakage was measured with extravasation of Evans blue dye (30 mg/kg, injected intravenously 5 minutes before the injection of PAF) by means of spectrophotometry and fluorescence microscopy. Five Sprague-Dawley rats were pretreated with NG-nitro-L-arginine methyl ester (L-NAME; 10 mg/kg, intravenously injected 1 hour before the injection of PAF) to inhibit NO synthase, and control rats (n = 4) were pretreated with normal saline solution. The average amount of extravasated Evans blue dye was significantly lower in the L-NAME-pretreated rats than in the control rats (t-test, p < .01). Tissue sections of the L-NAME-pretreated rats clearly showed a decreased extravasation of Evans blue dye on fluorescence microscopy. In conclusion, pretreatment with L-NAME clearly inhibited PAF-induced microvascular leakage in the nasal mucosa and trachea of rats. This finding implies that PAF may activate the constitutive endothelial NO synthase in the microvessels, and that activated endogenous NO may mediate PAF-induced microvascular leakage in rat airways.

Small cell carcinoma of the larynx: imaging findings.

Small cell carcinoma of the larynx is an uncommon epithelial tumor, which is the most aggressive subtype of neuroendocrine carcinomas. Because of its nonspecific clinical and radiological manifestations, the diagnosis of small cell carcinoma of the larynx is essentially based on the light microscopic examination aided by electron microscopy or immunohistochemical staining. We report a case of supraglottic small cell carcinoma accompanied by large bilateral cervical lymph node metastasis ocurring in a 70-year-old man. On CT scans, no area of low attenuation indicating necrosis was demonstrated within such large metastatic lymph nodes. We suggest that small cell carcinoma of the larynx should be included in the diagnostic considerations when a laryngeal mass is accompanied by large cervical lymph nodes without necrosis shown by CT.

Origin and distribution of NADPH diaphorase-positive nerves in rat nasal mucosa.

The aim of this study was to localize the distribution of (reduced) nicotinamide-adenine dinucleotide phosphate (NADPH) diaphorase-positive nerves in the rat nasal mucosa by NADPH diaphorase histochemistry, and to determine its origin by utilizing retrograde tracing with Fluoro-Gold (FG). Fine varicosities of NADPH diaphorase-positive nerve fibers were distributed around blood vessels (arterioles in particular), submucosal glands, and the subepithelial layer of the nasal mucosa. Most of the ganglion cells and nerve fibers in the sphenopalatine ganglion, and a few ganglion cells in the trigeminal ganglion, were stained by NADPH diaphorase, but no NADPH diaphorase-positive ganglion cells were found in the superior cervical ganglion. Retrograde tracing with FG and co-localization of NADPH diaphorase demonstrated that the FG-labeled ganglion cells in the sphenopalatine ganglion were NADPH diaphorase-positive, but the FG-labeled ganglion cells in both the trigeminal and the superior cervical ganglia were NADPH diaphorase-negative. In conclusion, NADPH diaphorase-positive nerves distribute around blood vessels, around submucosal glands, and in the subepithelial layer of the rat nasal mucosa, and their origin is the sphenopalatine ganglion. These findings imply that nitric oxide may be co-localized to the cholinergic innervation and be involved in vasomotor and secretomotor control of the nasal mucosa.

Odontogenic versus nonodontogenic deep neck space infections: CT manifestations.

PURPOSE: The purpose of this study was to evaluate deep neck space infection (DNSI) with particular attention to the differences in the spaces involved and in complications between odontogenic and nonodontogenic groups with CT. METHOD: Forty-four patients (21 odontogenic and 23 nonodontogenic) were included in this study. Among odontogenic DNSI cases, 15 had dental infection in the second or third mandibular molar. We compared the CT features between odontogenic and nonodontogenic DNSI cases, with special emphasis on the differences in the spaces involved and in the rate and type of complications. RESULTS: In all patients, CT clearly differentiated abscess from cellulitis. The most common spaces involved in 21 patients with odontogenic DNSI were the parapharyngeal (n = 18), the submandibular (n = 18), the anterior visceral (n = 13), the masticator (n = 9), and the sublingual (n = 7) spaces. In contrast, in 23 patients with nonodontogenic DNSI, the anterior visceral space (n = 14) was most frequently involved. The parapharyngeal, submandibular, and masticator spaces were statistically more frequently involved in odontogenic than in nonodontogenic DNSI (p < 0.05). Twenty-two patients had one or more complications shown by CT, of which airway compromise was more frequent and severe in odontogenic than in nonodontogenic DNSI. CONCLUSION: We conclude that the parapharyngeal, submandibular, and masticator spaces are more significantly vulnerable in odontogenic DNSI than in nonodontogenic DNSI. The predilection for certain spaces of the neck in odontogenic DNSI seems to originate from the intimate relationship of the mandibular molars to the adjacent deep neck spaces.

Bone erosion caused by sinonasal cavernous hemangioma: CT findings in two patients.

We report two cases of cavernous hemangioma originating in the sinonasal cavity. Although CT showed some enhancing areas within both tumors, the substantial bone destruction caused by these tumors made it difficult to differentiate them from the more common malignant epithelial tumors. Angiography was performed in one patient and showed characteristic pooling of contrast material.

[Infection status of larval anisakids in Astroconger myriaster collected from the Southern Sea near Pusan].

A study was presented on the anisakid larvae in Astroconger myriaster which were caught at the Southern Sea and saled at Pusan area. The nematodes were morphologically classified into Anisakis sp. and Contracaecum sp. after fixation in 70% ethanol and clearing in lactophenol. Total of 1,768 larval anisakids were collected from 259 (67.8% positive rate) out of 382 examined A. myriaster. Total 642 larvae of Anisakis sp. were obtained from 94 (24.6%) and 1,126 Contracaecum sp. were recovered from 165 (43.1%) fish. The average number of worms per infected fish was 4.6. The infection rate increased according to the length of fish, and all of the fish over 71 cm were found infected. The numbers (proportions) of recovered worms by the organs were 1,440 (80.5%) in the omentum, 166 (9.4%) in the intestine, 107 (6.0%) in the stomach, 32 (1.8%) in the skin, 18 (1.0%) in the muscle, 13 (0.7%) in the liver, and 2 (0.1%) in the head. The larvae in the muscle may infect the humans who are enjoying raw sliced meat of the fish.