Generation of a three-dimensional ultrastructural model of human respiratory cilia.

The ultrastructures of cilia and flagella are highly similar and well conserved through evolution. Consequently, Chlamydomonas is commonly used as a model organism for the study of human respiratory cilia. Since detailed models of Chlamydomonas axonemes were generated using cryoelectron tomography, disparities among some of the ultrastructural features have become apparent when compared with human cilia. Extrapolating information on human disease from the Chlamydomonas model may lead to discrepancies in translational research. This study aimed to establish the first three-dimensional ultrastructural model of human cilia. Tomograms of transverse sections (n = 6) and longitudinal sections (n = 9) of human nasal respiratory cilia were generated from three healthy volunteers. Key features of the cilium were resolved using subatomic averaging, and were measured. For validation of the method, a model of the well characterized structure of Chlamydomonas reinhardtii was simultaneously generated. Data were combined to create a fully quantified three-dimensional reconstruction of human nasal respiratory cilia. We highlight key differences in the axonemal sheath, microtubular doublets, radial spokes, and dynein arms between the two structures. We show a decreased axial periodicity of the radial spokes, inner dynein arms, and central pair protrusions in the human model. We propose that this first human model will provide a basis for research into the function and structure of human respiratory cilia in health and in disease.

The airway antigen sampling system: respiratory M cells as an alternative gateway for inhaled antigens.

In this study, we demonstrated a new airway Ag sampling site by analyzing tissue sections of the murine nasal passages. We revealed the presence of respiratory M cells, which had the ability to take up OVA and recombinant Salmonella typhimurium expressing GFP, in the turbinates covered with single-layer epithelium. These M cells were also capable of taking up respiratory pathogen group A Streptococcus after nasal challenge. Inhibitor of DNA binding/differentiation 2 (Id2)-deficient mice, which are deficient in lymphoid tissues, including nasopharynx-associated lymphoid tissue, had a similar frequency of M cell clusters in their nasal epithelia to that of their littermates, Id2(+/-) mice. The titers of Ag-specific Abs were as high in Id2(-/-) mice as in Id2(+/-) mice after nasal immunization with recombinant Salmonella-ToxC or group A Streptococcus, indicating that respiratory M cells were capable of sampling inhaled bacterial Ag to initiate an Ag-specific immune response. Taken together, these findings suggest that respiratory M cells act as a nasopharynx-associated lymphoid tissue-independent alternative gateway for Ag sampling and subsequent induction of Ag-specific immune responses in the upper respiratory tract.

Toxic effect of formaldehyde on the respiratory organs of rabbits: a light and electron microscopic study.

In this study, the effect of direct exposure of formaldehyde in different concentration was observed in 14 rabbits aged 3-6 months and weighing 1100-1200 g. The animals were divided into two groups with six animals in each group, and two animals were kept as control. The animals of group I were exposed to 10% formalin for 12 weeks and those of group II to 40% formalin solution for 6 weeks. After completion of the experimental periods, the animals were killed and the tissue samples were collected from the nasal cavity, trachea and lungs in 10% neutral buffered formalin and Karnovsky's fixative to examine the histological and electron microscopic changes in the organs. The mucosal cells of nasal cavity showed loss of cilia and epithelial metaplasia was observed in places. There was vascular congestion and mild subepithelial odema. The tracheal epithelium was organized with hyperchromatic nuclei. There was subepithelial odema along with lymphomononuclear cellular infiltration. There was marked emphysema evident as bulla formation of air spaces due to rupture of interalveolar septum. An increased cellularity of alveolar wall was observed, resulting in its thickening. The epithelial lining of bronchioles showed loss of mucosal folds and hyperplasia of cells along with peribronchial lymphomononuclear cellular infiltration. Thickening of wall of blood vessels was evident. Congestion and haemorrhages were observed in places. It is concluded that the histopathological changes were more remarkable in the animals exposed to 40% formaldehyde for short duration than the animals exposed to 10% formaldehyde for longer duration with a more severe effect on the upper part of the respiratory tract than the lower one.

Hybrid peripheral nerve sheath tumor of the nasal cavity showing schwannomatous, neurofibromatous, and perineuriomatous areas.

Soft tissue hybrid peripheral nerve sheath tumors (PNST), including schwannoma-perineurioma or neurofibroma-perineurioma, have recently been described. However, there are no reports on hybrid PNST arising in the nasopharyngeal area. In this article, we report such a case. A 58-year-old Japanese man presented with nasal obstruction and was found to have bilateral polypoid lesions in the middle meatus of the nose. Subsequently, nasal polypectomy was performed. Histologically, the tumor consisted of three components including schwannoma, neurofibroma, and perineurioma. Immunohistochemically, schwannoma, neurofibroma, and perineurioma components were positive for S-100 protein, CD34, and epithelial membrane antigen, respectively. In conclusion, this is the first case of hybrid PNST reported to occur in the nasopharyngeal area. Pathologists should be aware of the possibility that hybrid PNST may present outside soft tissue.

Vascular endothelial growth factor drives autocrine epithelial cell proliferation and survival in chronic rhinosinusitis with nasal polyposis.

RATIONALE: The pathogenesis of nasal polyps in chronic rhinosinusitis is poorly understood. OBJECTIVES: These studies seek to implicate a functional role for vascular endothelial growth factor (VEGF) in perpetuating primary nasal epithelial cell overgrowth, a key feature of hyperplastic polyps. METHODS: Comparison of VEGF and receptor expression was assessed by ELISA of nasal lavage, immunohistochemistry of sinus tissue, flow cytometry of nasal epithelial cells, and ELISA of supernatants. VEGF-dependent cell growth and apoptosis were assessed with blocking antibodies to VEGF, their receptors, or small interfering RNA knockdown of neuropilin-1 by cell proliferation assays and flow cytometric binding of annexin V. MEASUREMENTS AND MAIN RESULTS: VEGF protein was sevenfold higher in nasal lavage from patients with polyposis compared with control subjects (P < 0.001). We also report elevated expression of VEGF (P < 0.012), receptors VEGFR2 and phospho-VEGFR2 (both P < 0.04), and identification of VEGF coreceptor neuropilin-1 in these tissues. Nasal epithelial cells from patients with polyps demonstrated faster growth rates (P < 0.005). Exposure of cells to blocking antibodies against VEGF resulted in inhibition of cell growth (P < 0.05). VEGF receptor blockade required blockade of neuropilin-1 (P < 0.05) and resulted in increased apoptosis (P < 0.001) and inhibition of autocrine epithelial VEGF production (P < 0.05). CONCLUSIONS: These data demonstrate that VEGF is a novel biomarker for chronic rhinosinusitis with hyperplastic sinonasal polyposis that functions in an autocrine feed-forward manner to promote nasal epithelial cell growth and to inhibit apoptosis. These findings implicate a previously unrecognized and novel role of VEGF functioning through neuropilin-1 on nonneoplastic primary human airway epithelial cells, to amplify cell growth, contributing to exuberant hyperplastic polyposis.

Olfactory neuroepithelioma: an immunohistochemical and ultrastructural study.

Three cases of olfactory neuroepithelioma are presented in this report. Histologically, these tumors were composed of small cells with round to oval, relatively hyperchromatic nuclei and scanty cytoplasm. The tumor cells were occasionally observed in tubular formations or rosette-like arrangements. Immunohistochemically, the tumor cells showed a positive reaction for cytokeratin AE1, cytokeratin CAM5.2, Ber-EP4, antisynaptophysin and anti-S100 protein in all cases. In two cases, LH-RH was detected in the tumor cells. Ultrastructurally, the tumor cells had the differentiation features of olfactory epithelium. Olfactory neuroepithelioma is a rare occurrence and it can be very difficult to distinguish olfactory neuroepithelioma from small cell carcinoma, neuroendocrine carcinoma and so-called "olfactory neuroblastoma" on the basis of hematoxylin and eosin stained sections alone. In controversial cases, a diagnosis of olfactory neuroepithelioma must be substantiated by ultrastructural and immunohistochemical findings, particularly regarding the detection of Ber-EP4 and LH-RH immunoreactivity.

[Pathological and ultrastructural observation on the epithelia of nasal cavity and nasal sinuses in chronic sinusitis and nasal polyps after endoscopic sinus surgery].

OBJECTIVE: To research the restoration characteristics of epithelia in nasal cavity and nasal sinuses with chronic sinusitis and nasal polyps after endoscopic sinus surgery,and to provide basis for improving the treatment after operation. METHOD: Twenty patients with chronic sinusitis and nasal polyps after endoscopic sinus surgery were observed. The "Vesicle tissues" situated ostiomeatal complex (OMC) were observed with light and transmission electron microscopy after operation of 7-14 days. RESULT: (1) The "Vesicle tissues" were off white or buff, some contained liquid, and some were parenchyma under the endoscopy. (2) The epithelia of "Vesicle tissues" were pseudostratified ciliated columnar epithelium (16/20), and some were stratified squamous epithelium (2/20), some were squamous metaplasia in pseudostratified ciliated columnar epithelium (2/20). Lamina propria were edema. Inflammation cells infiltrated epithelial lining and subepithelial lining. We found mucous gland, mixed gland and glandular duct under subepithelial lining,and small vascular ectasia under light microscopy. (3) Transmission electron microscope: epithelia were pseudostratified ciliated columnar epithelium, cilia were in good order, microvilli located between cilia. The cross section of majority cilia were 9 + 2 form microtubule, but in some cilia we could not find microtubule and could only find one central microtubule. Golgi complex were up growth, and endoplasmic reticulum expand, and multi-mitochondrion were coagulation degeneration in epithelial cells. Some mitochondrion were 1-2 degree swelling and the lysosome increased. Inflammation cells infiltrated epithelial lining. Majority were neutrophil and lymphocyte, but we also found eosinophil and plasmacyte. CONCLUSION: "Vesicle tissues" is the manifestation of active epithelia regeneration in nasal cavity and nasal sinuses after endoscopic sinus surgery, it's the earlier period of imbalance regeneration of the epithelization in postoperative cavity. "Vesicle tissues" is similar to the nasal polyp histopathology, and it is phenomena of limited pathological rebuilding in earlier period. Cleaning "Vesicle tissues" can effectively control the nasal polyps relapse and impel the postoperative cavity to epithelization.

Histological evaluation of age-related changes in human respiratory mucosa of the middle turbinate.

Though the lining of the healthy human nose is subject of numerous investigations, age-related changes have attracted little attention. Furthermore, varying sampling sites complicate the evaluation of the available information. Reference is needed for evaluation of abnormal conditions, e.g. in persons with sleep apnea. Biopsy samples from the middle turbinate of 40 healthy humans aged 5 to 75 years were examined. Tissue samples were fixed immediately in glutaraldehyde and embedded in Epon for semi-thin sectioning and blind histological evaluation. In all age groups, patchy arrangement of different epithelial types were found. Ciliated epithelium decrease with age. Stratified and atrophic epithelial types show striking changes. Thin atrophic epithelium with conspicuously thickened basement membranes is only seen above the age of 40 years and is frequently found in older subjects. Stratified epithelial types initially increase with age, but decrease above 50 years. In the middle aged group (26 to 50 years) we found a remarkably high amount of squamous metaplasia, resulting in overall thicker epithelium becoming thinner in older subjects. In contrast, basement membranes are thinnest in the middle aged group. In conclusion, evaluating the histology of nasal respiratory epithelium must take pronounced age-related physiological changes into account.

Disappearance of epidermal growth factor receptor is essential in the fusion of the nasal epithelium.

Abstract Epidermal growth factor (EGF) and receptor (-R) signaling pathway is required for epithelial cell growth and differentiation such as the degeneration of the medial edge epithelial cells during the fusion process of secondary palate formation. As epithelial fusion takes place during primary palate formation, we investigated the involvement of the EGF-R in fusion of the medial (MNP) and lateral (LNP) nasal prominences of the mouse embryo was examined. Immunoreactivity of EGF-R was investigated in embryonic day 10 embryos (32-37 somite stages). The EGF-R immunoreactivity was observed in the nasal epithelia of the presumptive fusion area before fusion. It became undetectable just prior to the fusion and faintly reappeared at the time of the fusion. In contrast, the non-fusing epithelial cells of the nasal groove maintained the immunoreactivity throughout these stages. In order to elucidate whether the EGF/EGF-R signaling pathway was involved in nasal epithelial fusion, EGF solution was injected into the exocoelum of explanted mouse embryos, and the embryos were cultured for 18-24 h by whole embryo culture (WEC). This exogenous EGF inhibited fusion of nasal prominences in 66.7-81.5% of the embryos. Treatment with EGF for 4-14 h showed that exogenous EGF disturbed the EGF-R disappearance and normal alteration of epithelial cell morphology in the fusion area. These results suggest that temporal disappearance of the EGF/EGF-R signaling from presumptive fusion of the nasal prominences is required for morphological change of the epithelial cells leading to the fusion of MNP and LNP.

Rhinosporidiosis in a domestic cat.

Rhinosporidiosis was diagnosed in a domestic shorthair cat from a suburb of Washington DC, USA. The clinical presentation of protracted sneezing and epistaxis was associated with a polypoid lesion in the right nostril. Light microscopic examination revealed a polypoid lesion with numerous sporangia containing maturing endospores. Free endospores were present in the stroma of the polyp and lumen of the nasal cavity. Transmission electron microscopy revealed ultrastructural features typical of Rhinosporidium seeberi. The case was followed clinically for a total of 70 months and there were five attempts at surgical excision. This is the first reported case of rhinosporidiosis in a domestic cat.

Monotypic angiomyolipoma of the nasal cavity: a heretofore undescribed occurrence.

A monotypic angiomyolipoma of the nasal cavity in a 34-year-old woman is described. Tumor cells were spindled or epithelioid and contained glycogen and diastase-resistant PAS-positive granules. There were few mitoses, and necrosis was absent, indicating a benign tumor. The stroma was markedly vascular, and a few adipocytes were seen in one area. Cells were positive for melanocyte and muscle markers. Electron microscopy revealed abundant dense granules. Although melanin was absent histochemically, it was present using a chemical assay, and the granules may, therefore, be atypical melanosomes. Fine actin filaments, attachment plaques and lamina were present. Initial assessment of the lesion indicated malignant melanoma, but the immunostaining and histologic features indicated monotypic angiomyolipoma. To the best of our knowledge, this is the first such case in the nasal cavity.

Use of ciliogenesis in the diagnosis of primary ciliary dyskinesia in a dog.

Primary ciliary dyskinesia is a congenital condition that may cause chronic rhinitis and bronchopneumonia. Primary ciliary dyskinesia may be diagnosed by induction of ciliogenesis by use of in vitro cell culture. Induction of ciliogenesis allows for differentiation between primary and secondary ciliary dyskinesia.

Toxicologic and carcinogenic effects of the type IV phosphodiesterase inhibitor RP 73401 on the nasal olfactory tissue in rats.

RP 73401, a type IV phosphodiesterase inhibitor, caused toxic effects in the nasal olfactory region of Sprague-Dawley rats when administered by either oral or inhalation exposure. A single oral administration of RP 73401 (at a dose of > or = 50 mg/kg) or 5-day inhalation exposure (1 hr/day) at a dose of approximately 1.0 mg/kg per day caused degeneration and sloughing of the olfactory surface epithelium. Degeneration and loss of Bowman's glands were noted in the underlying lamina propria and submucosa. Electron microscopy of these lesions demonstrated that sustentacular cells and the epithelial cells lining Bowman's glands were the primary target cells in the olfactory mucosa. The earliest ultrastructural changes detected in these cells were dilatation and vesiculation of the endoplasmic reticulum, suggesting that metabolic activation is important for the toxic effects. In repeated-dose studies, 13 wk of oral dosing at 2.0 or 6.0 mg/kg per day resulted in subtle disorganization of the olfactory epithelium, whereas basal cell hyperplasia in the olfactory epithelium was identified in a 6-month inhalation study at a dose of 1.0 mg/kg per day. A 2-yr inhalation carcinogenicity study resulted in tumors of the nasal olfactory region in rats treated at 0.5 and 1.0 mg/kg per day. Most tumors were classified as olfactory neuroblastomas, and immunohistochemistry on selected tumors was consistent with their being of neuroectodermal origin. Of the species studied (rat, mouse, and dog), the olfactory toxicity of RP 73401 was confined to the rat, and the toxicity was likely related to metabolic activation by olfactory epithelial cells rather than the phosphodiesterase activity of the compound.

[Variations of the middle meatus mucosa ultrastructure after endoscopic sinus surgery].

OBJECTIVE: To explore the variations of middle meatus ultrastructure after endoscopic sinus surgery. METHOD: 10 cases whose middle meatus mucosa recovered well after undergoing endoscopic sinus surgery were screened, and postoperative electron microscope examinations of middle meatus mucosa were made in the first, second, third and forth month. RESULT: In the first month after operation, there was obvious fibre proliferation in the mucosa. In the second month, there was fibre proliferation and dissolution existing simultaneously. In the third month, the mucosa's structure resumed fundamentally to normal, but its function was not perfect. In the forth month, the mucosa was completely normal and can function normally. CONCLUSION: The mucosa of middle meatus can resume completely after endoscopic sinus surgery but need at least four months. It is very important to have a long time reexamination for improving therapeutic effect.

Morphology and cytology of the nasal cavity and vomeronasal organ in juvenile and adult blind mole rats (Spalax ehrenbergi).

The blind mole rat (Spalax ehrenbergi) is a fossorial solitary rodent which exhibits extensive intraspecific aggression and uses scent markings to deter contraspecific invaders. Mole rats of different ages were captured near Tel Aviv, Israel, and sacrificed by an overdose of Xylazine hydrochloride. Olfactory epithelium sites from the nasal cavity (NC) and the vomeronasal organ (VNO) were dissected and fixed for light and electron microscopy. The mole rat's olfactory epithelium of the NC consists of several cell types, of which two types are supporting cells that comprise both microvilli and cilia but differ in staining and the presence of rough endoplasmic reticulum. The third type has no cilia. Secretory goblet cells were frequent among supporting cells of adults alone. Two types of receptor cells protrude into the NC with olfactory knobs at their apical region; one type has up to 177.6 +/- 9.4 cilia per knob plus microvilli, while the other type has only microvilli. The third type of sensory cell has no knob and contains microvilli only. The basal epithelium layer consists of short-bodied cells with round nuclei. The VNO of the mole rat is situated beneath the nasal septum, consisting of supporting, sensory, and basal cell types, with many cilia at the apical portion. At its anterior part, the VNO is connected to the NC by narrow canals. The abundance of cilia and microvilli in the mole rat olfactory cells provides the first anatomical evidence for their olfactory acuity. Such acuity is important in mole rats, compensating for their loss of vision and enabling them to detect and avoid rivals prior to potential aggressive encounters as well as to select food plants during foraging.

[Comparative studies of ciliary epithelial morphological and radiologic findings in the osteomeatal complex].

In this study, we evaluated quantitatively preoperative coronal CT scan in 30 nasal cavities of 22 patients with chronic sinusitis who underwent functional endoscopic sinus surgery. The ciliated area of the osteomeatal complex (OMC) from these patients was quantitatively observed by scanning electron microscope and image analysis. Our results showed a positive correlation between ciliary epithelial pathological changes in OMC and disease degree of this area in CT scan.

Histological investigations of the nasal mucosa in human fetuses.

The adult nasal mucosa has been exposed to various external agents and selected physiological conditions. Changes in intranasal airflow influenced the morphological appearance of the mucosa. Studies of agents on the fetal mucosa and its development may contribute to better understanding of the morphology of the nasal mucosa. The authors studied the nasal mucosa of 20- to 26-week-old fetuses using light microscopy and scanning and transmission electron microscopy. Findings showed that this developing nasal mucosa took part in the production and movement of mucus in the nasal cavity.

[Primary nasal tuberculosis]. / Tuberculosis nasal primaria.

Nasal tuberculosis is a rare entity since it early diagnosis and the improvements in treatment. The mucous membrane of the nose is scanty auspicious for this pathology in spite of being an important entrance door for Koch's bacillus. We report one case of nasal tuberculosis without other primary focal point and emphasize the importance of biopsy and the histo-pathological study in order to reach the positive diagnosis and the healing "ad integrum" by means of suitable antibiotic drugs.