A preclinical model for laryngeal transplantation: anatomy and mucosal immunology of the porcine larynx

BACKGROUND

A major step in translating work on laryngeal transplantation into clinical practice is the establishment of a preclinical model. We have investigated the anatomy and mucosal immunology of the porcine larynx in eight Minnesota Minipigs (12-37 weeks).

METHODS

Neck dissections were carried out and the vascular tree was mapped. Snap-frozen biopsies from epiglottis, supraglottis, glottis, and subglottis were prepared for conventional histology, immunohistochemistry (CD45), and single and two-color immunofluorescence (CD3, MHC-II, CD45).

RESULTS

The anatomy of the laryngeal skeleton was broadly similar to that of the human larynx. The blood supply is predominantly via the caudal thyroid vessels, with assistance from the cranial laryngeal artery. The porcine larynx is clearly highly immunologically active. Structured collections of leukocytes were found in the mucosal epithelium, around tubuloacinar glands, and occasionally in the submucosa. MHC-II and CD 3 cells were predominantly found within the epithelium. The highest densities of all cell types were observed in the epiglottis, tailing off caudally. The lowest densities were seen in the vocal cords.

CONCLUSIONS

The porcine larynx is both anatomically and immunologically similar to the human larynx and contains a high level of immunological organization. It presents an ideal preclinical model for laryngeal transplantation.

Anitschkow myocytes or cardiac histiocytes in human hearts

The caterpillar chromatin pattern of the nucleus in longitudinal section and owl-eye appearance in transverse section characterize the Anitschkow cell of Aschoff bodies in rheumatic heart disease. Determining whether it is of muscle origin or cardiac histiocyte has been a source of controversy for many years. In a study of fetal and neonatal hearts from humans, vesicular nuclei often displaying the Anitschkow chromatin pattern were the predominant cell type in the myocardium. Because a similar pattern was also observed in two cell types related to laryngeal cartilage and the neighbouring fibrous tissue in a six week old neonate, it was concluded that the Anitschkow chromatin pattern probably indicates cellular immaturity rather than any specific cell type.

Comparison of adherence to and penetration of a human laryngeal epithelial cell line by group A streptococci of various M protein types

Clinically isolated group A streptococci (GAS) of different M protein types were studied using aminoglycoside exclusion and [2,8-3H]adenine radiolabeled GAS assays to compare the abilities of different strains to adhere to and internalize within human laryngeal epithelial (HEp-2) cells. GAS isolated from patients with pharyngitis and GAS isolated from patients with more severe disease, such as necrotizing fasciitis, adhered to and penetrated HEp-2 cells equally well. M3, M4, M6, and M12 strains adhered to and were internalized within HEp-2 cells more than M1 strains. M18 GAS producing hyaluronic acid capsules were less adherent and less invasive than the M3, M4, M6, and M12 strains. An M3-producing GAS strain and its M protein-deficient isogenic strain adhered similarly to HEp-2 cells, but the M protein-deficient strain exhibited greater penetration. Preincubation of HEp-2 cells with an N-terminal synthetic M3 peptide did not alter the adherence or penetration by an M3 strain. In summary, this study demonstrates that GAS from invasive and non-invasive disease adhere to and penetrate HEp-2 cells equally well and that multiple strains of GAS with various M protein types have the ability to adhere to and penetrate HEp-2 cells.

Involvement of host cell tyrosine phosphorylation in the invasion of HEp-2 cells by Bartonella bacilliformis

We have provided evidence that exposure of human cells to protein kinase inhibitors results in decreased invasion of these cells by Bartonella bacilliformis in a dose-dependent manner. Preincubation of human laryngeal epithelial cells in the presence of genistein, a tyrosine protein kinase inhibitor, decreased the invasion of these cells by B. bacilliformis significantly. Further, exposure of normal human umbilical vein endothelial cells to staurosporine, a potent inhibitor of protein kinase C and some tyrosine protein kinases, resulted in a considerable reduction in the number of organisms internalized by these cells. Moreover, Bartonella infection of HEp-2 cells induced tyrosine phosphorylation of several Triton X-100 soluble proteins with approximate molecular masses of 243, 215 179, 172 (doublet), 160, 145 and 110 kDa that were absent or reduced in the presence of genistein in cells after 1 h of infection. Exposure of HEp-2 cell monolayers to anti-alpha 5 and anti-beta 1 chain integrin monoclonal antibodies resulted in a moderate decrease in the invasion of these cells, suggesting a possible role of alpha 5 beta 1 integrins in the uptake of Bartonella into nucleated cells.

Lectin histochemistry of laryngeal squamous cell carcinomas

A panel of five biotinylated lectins was applied to study the presence and distribution of membrane carbohydrate residues in the normal laryngeal epithelium and in laryngeal squamous cell carcinomas (SCCs) of 86 patients with the avidin-biotin peroxidase complex technique. The lectin-binding pattern of well-differentiated SCCs was comparable to that of the spinous cells of the normal laryngeal epithelium. In the less differentiated SCCs, staining of the keratinocyte plasma membrane with lectins was either reduced or absent, indicating a decline in the glycosylation of cell surface glycoconjugates. The lectins applied here could be used in the rapid assessment of less-differentiated areas within a laryngeal SCC, but they cannot be regarded as reliable markers of laryngeal keratinocytes undergoing malignant transformation.

Expression of invasin and motility are coordinately regulated in Yersinia enterocolitica

The Yersinia enterocolitica inv gene encodes the primary invasion factor invasin, which has been previously shown to be critical in the initial stages of infection. The expression of inv is influenced by growth phase and temperature and is maximal during late exponential-early stationary phase at 23 degrees C. In addition, motility of Y. enterocolitica is regulated by temperature. Y. enterocolitica cells are motile when grown at lower temperatures (30 degrees C or below), while bacteria grown at 37 degrees C are nonmotile. This study was initiated to determine the molecular basis for the temperature regulation of inv expression. Two mutants were isolated that both showed a significant decrease in invasin expression but are hypermotile when grown at 23 degrees C. The first mutant (JB1A8v) was a result of a random mTn5Km insertion into the uvrC gene. The uvrC mutant JB1A8v demonstrated a significant decrease in inv and an increase in fleB (encodes flagellin) expression. These results suggest that expression of inv and flagellin genes is coordinated at the level of transcription. The second regulatory mutant, JB16v, was a result of a targeted insertion into a locus similar to sspA which in E. coli encodes a stationary-phase regulator. The E. coli sspA gene was cloned and assayed for complementation in both of the regulatory mutants. It was determined that E. coli sspA restored invasin expression in both the uvrC mutant and the sspA mutant. In addition, the complementing clone decreased flagellin levels in these mutants.

Upper airway motor outputs during vomiting versus swallowing in the decerebrate cat

Swallowing and vomiting are antagonistic motor acts; nevertheless, vomiting can be immediately followed by swallowing. The purpose of this study was to clarify the interrelationship between these two behaviors, particularly in regard to comparing the upper airway motor patterns at the end of the expulsion phase with those during subsequent swallowing. Experiments were conducted using both paralyzed and non-paralyzed decerebrate cats, in which recordings were obtained either from upper airway muscles, the diaphragm and abdominal muscles or from the nerves that innervate those muscles. The activity patterns of most nerves recorded in paralyzed animals were consistent with the behavior recorded in non-paralyzed animals from the muscles innervated by those nerves, with the exception of the cricothyroid and stylopharyngeus muscles. Vomiting can be divided into a series of retches followed by expulsion, which itself can be further subdivided into three phases. The final stage of expulsion, characterized by burst-like exaggerated activity of the laryngeal elevator thyrohyoid and the pharyngeal constrictors, proved to be different from pharyngeal swallowing, as judged from differences in the spatio-temporal patterns of the upper airway motor outputs. However, post-vomiting swallowing activity was still observed even after total deafferentation of the laryngeal and pharyngeal areas in paralyzed animals. It is therefore likely that the central processes for vomiting and swallowing closely relate in generating these two behaviors.

CGRP and substance P in intraepithelial neuronal structures of the human upper respiratory system

The distribution of intraepithelial nerve fibres and neuroendocrine cells within the surface and glandular epithelium of human nasal mucosa and larynx was examined using immunohistochemical techniques. Neuronal structures were immunostained for the general neuroendocrine marker protein gene-product (PGP) 9.5, and the two neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) using immunofluorescence and streptavidin-biotin-peroxidase complex (S-ABC) methods. Intraepithelial nerve fibres with free nerve endings contained PGP 9.5 and were found within the respiratory surface epithelium of the nasal mucosa and the squamous epithelium of the larynx. A subpopulation of these nerve fibres showed positive immunoreactivties with antibodies against SP and CGRP. Nerve fibres within the ductal epithelium of subepithelial excretory ducts passing the basal membrane and reaching the luminal part were detected. These nerve fibres showed CGRP-like immunoreactivity but not for SP. A dense network of nerve fibres within the squamous surface epithelium was detected in the subglottic and epiglottic region containing CGRP and SP in a small subpopulation of nerve fibres. Single intraepithelial taste buds in the epiglottic region and neuroendocrine cells within the subglottic epithelium expressed PGP 9.5.

Larynx-associated lymphoid tissue (LALT) in young children

BACKGROUND

Mucosa-associated lymphoid tissue (MALT) plays a central role in mucosal immunity. Whereas the characteristics and function of MALT in the intestine are well established, almost nothing is known about MALT in the larynx.

METHODS

In this study we examined the morphology and the lymphocyte subset composition of MALT in the larynges of children who had died of sudden infant death or various defined traumatic or nontraumatic causes.

RESULTS

Organized lymphoid tissue was found in the supraglottic parts of the larynx in nearly 80% of the children in both groups. This lymphoid tissue showed all morphological signs of MALT, such as typical lymphoid follicles with germinal centers, infiltration of the overlying epithelium by lymphocytes, and high endothelial venules (HEV). Thus we will use the term LALT (larynx-associated lymphoid tissue) to refer to this tissue. The lymphoid follicles of LALT contained mainly B lymphocytes with some CD4+ lymphocytes in the germinal centers. Remarkably, T lymphocytes of both subset types and B lymphocytes were observed in comparable numbers in the parafollicular area.

CONCLUSIONS

We assume that LALT is a physiological structure of the larynx in young children. The morphology and the distribution of lymphocyte subsets are similar to those of MALT in the human gut. LALT may be a regular part of the mucosal immune system in young children with the role of respiratory inductive site for mucosal immunity.

Metabolic fate and effects of saturated and unsaturated fatty acids in Hep2 human larynx tumor cells

Previous studies have reported the presence of carnitine palmitoyltransferase I and II in tumor cells and the inhibitory effects of fatty acids on cell proliferation. The present work considered the metabolic fate of [14C] or [3H]-labeled fatty acids and their effects on cellular metabolism in Hep2 human larynx tumor cells. The rate of uptake of acetate was 45% of that of myristate, palmitate, oleate, linoleate and arachidonate. However, acetate was rapidly metabolized within the cell as seen by its low rate of accumulation as non-esterified fatty acid, < 5% of that of the other fatty acids. The incorporation of fatty acids into neutral lipid fractions showed palmitate and oleate primarily entered the phospholipid fraction, while linoleate and arachidonate entered equally the phospholipid and triacylglycerol fractions. Palmitate and oleate were oxidized to 14CO2 at higher rates than linoleate and arachidonate, with arachidonate being the least oxidized of the unsaturated fatty acids. Acetate was oxidized at 10-30 fold higher rates than the other fatty acids. Palmitate, oleate, linoleate and arachidonate all had significant inhibitory effects on the rate of glucose utilization by Hep2 cells, ranging from 25-38% inhibition and were found to inhibit cell proliferation by 17-73%. These findings suggest that certain fatty acids not only play a structural role in cellular metabolism, but may also have a potential regulatory role in the glycolytic pathway of Hep2 cells.

Similar distribution of mast cells and substance P- and calcitonin gene-related peptide-immunoreactive nerve fibers in the adult human larynx

The mechanisms causing supraglottic and subglottic edema in the human larynx are not fully understood. Substance P (SP)- and calcitonin gene-related peptide (CGRP)-containing nerve fibers and mast cells have been suggested to induce inflammation and edema in other parts of the body. In this study of the adult human larynx the distribution of mast cells was studied in relation to SP- and CGRP-containing nerve fibers. Substance P- and CGRP-immunoreactive nerve fibers and numerous mast cells were found in the epiglottis and in the subglottic region of the larynx. Only occasional mast cells and no nerve fibers showing SP- or CGRP-like immunoreactivity were found in the vocal cords. In conclusion, the present study has shown that the distribution of nerve fibers showing SP- and CGRP-like immunoreactivity and mast cells has a similar regional variability. As the highest density of SP- and CGRP-containing nerve fibers and mast cells was present in the regions of the larynx where edema occurs, SP, CGRP, and/or mast cells might be involved in the pathogenesis of edema.

Androgen-induced proliferation in the developing larynx of Xenopus laevis is regulated by thyroid hormone

Exposure to exogenous androgen regulates cell number in the developing larynx of Xenopus laevis and hormone-regulated laryngeal development requires secretion of thyroid hormone (TH). We sought to determine whether exposure to TH is both sufficient and necessary for androgen-evoked cell proliferation (androgen competency) in developing larynx. Androgen competency was not observed in the premetamorphic larynx (tadpole stage 53, before TH secretion) but was present just prior to metamorphic climax (stage 58, during TH secretion). However, when TH is administered precociously (between stages 48 and 50), androgen competency can be observed at stage 53. The stage 52 larynx expresses high levels of the mRNA for TH receptor alpha. The duration of TH exposure required at tadpole stage 48 is greater than 2 days; studies in juveniles indicate that TH exposure need not be maintained in order for androgen competency to persist. The effects of exposure to TH on androgen competency are long lasting and perhaps permanent. While organotypic cultures obtained from tadpoles during premetamorphosis (stage 52) can proliferate in vitro and proliferation is augmented by TH exposure as it is in vivo, precocious exposure to TH does not induce androgen competency. In contrast, androgen does evoke cell proliferation in cultures obtained from metamorphosing (stage 58) tadpoles; proliferation is confined to the cartilage component. Thus, unlike larynges in vivo, muscle will not proliferate in response to androgen, indicating the necessity for an additional factor not present in vitro. Androgen receptor mRNA expression, believed required for androgen competency, was assessed in vivo and in vitro. The tadpole larynx strongly expresses AR mRNA, expression does not require exposure to TH nor is expression diminished in culture.

Reconstruction of the laryngeal mucosa. A three-dimensional collagen gel matrix culture

OBJECTIVE

To prepare an in vitro reconstruction of the porcine laryngeal mucosa, for use in cell biological investigations and as a model for the study of laryngeal disease.

DESIGN

Using separately obtained epithelial cells and fibroblasts from porcine laryngeal mucosa, we reconstructed the laryngeal mucosa in a three-dimensional collagen gel matrix culture with air-liquid interface.

SUBJECTS

Porcine larynges were from 6-month-old pigs obtained from a local abattoir.

RESULTS

We successfully reconstructed the laryngeal mucosa in vitro, including epithelium and lamina propria. The epithelial cells showed five to eight cells in thickness and were well differentiated on the reconstructed lamina propria. The differentiation-specific cytokeratin was positive.

CONCLUSIONS

To our knowledge, this is the first report of a reconstruction of the laryngeal mucosa in a three-dimensional collagen gel matrix culture. Fibroblasts and air-liquid interface treatment exert a great influence on the proliferation and differentiation of the cultured epithelial cells. This culture system will help to provide an appropriate physiologic environment to study the differentiation and disease of the larynx.

Neuroendocrine cells in the cat laryngeal epithelium

The structure and distribution of neuroendocrine cells in the feline laryngeal epithelium were examined using immunohistochemical techniques. Neuroendocrine cells were often spindle shaped, with cytoplasmic processes directed towards the lumen and basement membrane. The apical portion of the cells usually reached the laryngeal lumen with microvillous projections. The cytoplasm always contained variable numbers of electrondense cored vesicles. The number of neuroendocrine cells decreased in the following order: subglottis, posterior glottis, supraglottis, anterior glottis. Neuroendocrine cells contained calcitonin gene-related peptide, substance P and/or 5-hydroxytryptamine. They also showed protein gene product 9.5 or neuron-specific enolase immunoreactivity. These observations suggest that neuroendocrine cells play a part in the regulatory function of the cat larynx by releasing various peptides. These substances may contribute to allergic reactions or control mucus secretion by acting via the endocrine or paracrine pathways and/or neurosecretory pathways.

Human larynx expresses isoforms of the oestrogen receptor

Commercially available enzyme immunoassays (EIAs) were used for oestrogen (ER) and progesterone (PR) receptor determination in the cytosol fraction of 118 human larynx cancer specimens and in the corresponding histologically proven non-malignant tissues. Fifty-one ER positive cancerous samples had corresponding non-cancerous tissues also expressing the receptor. A high resolution isoelectric focusing (IEF) technique followed by immunoblotting with the H222 anti-ER monoclonal antibody was used to evaluate the presence of ER isoforms in the 51 ER positive human larynx cancer specimens and in their corresponding non-malignant tissues. In both tissues, four ER isoforms were detected, with isoelectric points (pI) similar to those obtained in breast and endometrium carcinomas (6.1, 6.3, 6.6 and 6.8). A significant difference in the expression of ER isoforms between cancerous and non-cancerous tissue was found; precisely, the 94.1% of the ER positive non-malignant specimens co-expressed the four isoforms while they were detected in only the 35.5% of the malignant specimens (P < 0.0001 by Fisher's exact test). In larynx cancer, the concentration values of ER and PR did not correlate, nevertheless tumours co-expressing the four ER isoforms had PR levels significantly higher than those which did not (P = 0.02 by Mann-Whitney Wilcoxon sum rank test). To investigate the possibility that the isoforms of the monomeric 4S form of the ER (those with pI 6.3, 6.6, and 6.8) could dimerise, a cold agarose gel electrophoresis technique was used on IEF-separated ER isoforms. In summary, the evidence shows that all the isoforms are able to form homodimers and that the isoforms at pI 6.3 and 6.8 are able to dimerise with that at pI 6.6 but, under the same experimental conditions, they do not form the 6.3/6.8 heterodimer. It was concluded that: (1) the four isoforms of the ER are co-expressed by the non-malignant human larynx and the cancer loses the capacity to express some of them; (2) the complete complement of ER isoforms (all four) is needed for PR expression; (3) the monomeric 4S isoform with pI 6.6 has the capacity to form homo- and heterodimers, while the remaining two are only able to homodimerise.

Investigation of enterohemorrhagic Escherichia coli O157:H7 adherence characteristics and invasion potential reveals a new attachment pattern shared by intestinal E. coli

In this study, the interactions of enterohemorrhagic Escherichia coli (EHEC) O157 strains with human ileocecal (HCT-8) epithelial cells and HEp-2 cells were examined. EHEC adhered to, but did not invade, HCT-8 cells by the localized adherence mechanism and a heretofore unrecognized pattern which we called log jam. The log jam formation was (i) not observed on HEp-2 cells, (ii) independent of the EHEC eaeA gene required for localized adherence, and (iii) shared by pathogenic and nonpathogenic E. coli strains but not K-12 strains. The log jam phenotype may represent a basal means by which E. coli bacteria attach to the human intestine.

Three-dimensional reconstruction of the feline larynx with serial histologic sections

This paper reviews a new technique to develop high-resolution three-dimensional (3-D) images of the larynx using histological sections. Three-dimensional computer-reconstructed histological sections of the cat are used in this study to evaluate the recurrent laryngeal nerve (RLN) in its true anatomic course, with emphasis on its relationship to surrounding structures (laryngeal framework). A cat model was used because of specimen availability and technical ease of tissue preparation. Computer-reconstructed serial histologic sections add a new dimension to the study of laryngeal anatomy, laryngeal trauma, and growth patterns of laryngeal cancer. The technical aspects of three-dimensional reconstruction and future applications are discussed.

A tissue-culture model for the study of canine vocal fold fibroblasts

A tissue-culture model has been developed for the study of fibroblasts from the canine vocal fold. Laryngeal tissue (lamina propria) obtained from euthanized dogs is rinsed, cut into 1-mm3 pieces, and incubated in 5% carbon dioxide at 37 degrees C. A confluent monolayer is established within several days. Detectable levels of elastin in the tissue culture supernatant are measured by an indirect enzyme-linked immunosorbent assay. Various external agents have been shown to affect elastin production. The effects of KTP laser irradiation, hydrocortisone (1.3 mumol/L), transforming growth factor-beta (10 ng/mL), and human leukocyte elastase have been measured. Thus the canine vocal fold fibroblast tissue culture is established as a model for further investigations to improve wound healing and to understand the wound-healing process following laryngeal microsurgery.

Benign pathologic responses of the larynx

Benign laryngeal lesions were examined for patterns of injury indicated by deposition of fibronectin and collagen type IV. An immunoperoxidase technique was used to compare 33 fresh or paraffin-embedded tissues with regard to their staining of monoclonal antibodies directed against fibronectin and collagen type IV. Two types of patterns were recognized. One pattern showed intense fibronectin deposition in the superficial layer of the lamina propria, often coupled with basement membrane zone injury, indicated by thick collagen type IV bands. The other pattern showed rare basement membrane zone injury and very little fibronectin deposition. The first pattern correlated more with nodules, the second pattern more with Reinke's edema and some polyps. A better understanding of the effects of excessive deposition of structural glycoproteins such as fibronectin and of abnormal proteoglycan deposition may lead to a better characterization of vocal fold disease and its causation and, ultimately, better treatment.

Immunocytochemical survey of the neuroepithelial endocrine system in the respiratory tract of the Tokyo salamander, Hynobius nebulosus tokyoensis TAgo

The epithelial lining of the respiratory tract of urodeles has been shown to harbor an innervated system of neuroepithelial endocrine (NEE) cells. Even between phylogenetically closely related species, large differences have been reported in the appearance and chemical coding of the NEE system. Although urodeles are well suited for the purpose, none of the prior studies have provided an immunocytochemical survey of the NEE system in all parts of the respiratory tract. In the present study, many bioactive substances and a general marker were immunocytochemically demonstrated in serial sections of the entire respiratory tract of the Tokyo salamander, Hynobius nebulosus tokyoensis, a species in which neuroepithelial bodies (NEBs) were previously characterized at the electron microscopic level. In the current study, serotonin-immunoreactive solitary NEE cells were observed in variable numbers in the larynx, in all parts of the trachea, and in areas of the lungs covered with ciliomucous epithelium. Serotonin-containing NEBs, however, were detected in small cranial areas of the lung only. Solitary NEE cells were seen in the trachea and lungs of H. nebulosus tokyoensis by immunocytochemical staining for somatostatin, calcitonin, calcitonin gene-related peptide, and bombesin, but the number, localization, and appearance of the labeled NEE cells differed considerably. Only calcitonin-like immunoreactivity was also noted in some NEB-like cell clusters in the cranial parts of the lungs. Unlike many other vertebrates, neuron specific enolase was found to be a poor marker for the NEE system in the salamander species used in this investigation. It may be concluded that the NEE system of H. nebulosus tokyoensis contains at least five different bioactive substances.(ABSTRACT TRUNCATED AT 250 WORDS)

[Characterization of human laryngeal epithelial cells transfected with human papillomavirus type 16 DNA]

Human papillomaviruses (HPVs) are associated with tumor lesions of the larynx. In order to develop a model for investigating the role of HPV in human laryngeal carcinogenesis, normal human laryngeal epithelial cells (HLEC cells) were transfected with a cloned full-length HPV genome. The HPV type 16 (HPV-16) most often associated with cancer of the larynx induced an extended life-span in vitro of HLEC cells by exceeding 100 population doublings, while the HPV-11 that is associated with benign laryngeal papillomas failed to do so. The extended life-span cells (HLEC-16 cells) contained integrated HPV-16 DNA, expressed viral E6 and E7 mRNA, showed anchorage-dependent growth and were non-tumorigenic. Using indirect immunocytochemical staining, nuclear p53 protein was not detectable in any of the HLEC-16 cells, implying that HLEC -16 cells were negative for p53 gene mutations. HLEC-16 cells should be useful for studying mechanisms involved in proliferation, differentiation and neoplastic transformation of HLEC cells.

Expression of ras oncogene p21 protein in normal and neoplastic laryngeal tissues: correlation with histopathological features and epidermal growth factor receptors

Western blotting analysis of the p21 ras oncoprotein was performed in seven normal laryngeal mucosa specimens and 43 primary laryngeal cancers. Varying p21 levels, expressed as optical density (OD), were found in normal mucosa (median 1.94 OD, range 0.90-2.17 OD) and in primary laryngeal tumours (median 1.74 OD, range 0.30-6.37 OD). When p21 expression in laryngeal cancer was compared with the normal counterpart, higher levels were found in neoplastic than in normal laryngeal tissue (median 2.54 OD, range 1.76-6.37 OD, vs median 1.94 OD, range 0.90-2.17 OD) (P = 0.023). Immunohistochemical analysis demonstrated that most of the tumour cells (more than 70%) were immunostained while the stromal component was unreactive. No correlation between p21 expression and tumour location, stage and histopathological grade was observed. The correlation between ras p21 protein expression and epidermal growth factor receptor (EGFR) levels was also investigated. EGFR-positive cases did not show any difference in p21 expression with respect to EGFR-negative cases (median 1.52 OD, range 0.30-6.37 OD, vs median 1.84 OD, range 0.93-3.71 OD). Our findings suggest that overexpression of p21 protein is associated with a malignant phenotype in laryngeal cancer. Further studies should be undertaken to evaluate whether the assessment of p21 protein expression may have clinical significance in laryngeal cancer.

Ontogeny of endocrine cells in the respiratory system of Syrian golden hamsters. I. Larynx and trachea

The ontogeny of protein gene product 9.5 (PGP 9.5), serotonin (5-HT), calcitonin gene-related peptide (CGRP), and calcitonin (CT) immunoreactivity was evaluated in small-granule endocrine cells of hamster laryngotracheal epithelium from fetal day 11 to adulthood. Two centrifugal (proximal-to-distal) patterns of differentiation occur. The first pattern begins during fetal life. Endocrine cells, single and clustered in groups (presumptive- or protoneuroepithelial bodies, pNEBs), initially colocalize immunostaining for PGP 9.5, 5-HT, and CGRP in the larynx and proximal 2/3 of the trachea on day 12 and spread to the caudal trachea on day 13. 5-HT disappears fleetingly during the 24 h preceding birth; otherwise immunoreactivity for all three substances persists into adulthood. The clusters of endocrine cells survive beyond birth but are so diluted by expansion of the nonendocrine epithelium as to become inconspicuous. Since innervation was not actually observed, these clusters may persist as pNEBs, without developing connections to afferent or efferent nerve fibers. The second pattern concerns single small-granule cells stainable for CGRP but not for 5-HT. These cells first appear in the larynx and cartilaginous part of the cranial trachea on postnatal day 3, and in the middle and caudal trachea, on day 5. The cells increase in number on day 7. In adults, they predominate among endocrine cells of the cartilaginous region. A subset of these cells begins to co-express CT proximally on postnatal day 10, reaching the caudal end of the trachea by 3 weeks. A few elements of the older 5-HT-positive population may also become immunoreactive for CT in juvenile hamsters.

Electron microscopic immunohistochemical study of intra-epithelial nerve fibers in the canine larynx

Substance P (SP)-, calcitonin gene-related polypeptide (CGRP)-, and vasoactive intestinal polypeptide (VIP)-immunoreactive (IR) nerve fibers were observed in the epithelium of the canine subglottic region. To investigate the morphological differences among SP-, CGRP-, and VIP-IR nerve fibers in the epithelium, this study was performed by using immunohistochemical staining and electron microscopy, after which the origins of the nerve fibers were examined by denervation of the bilateral superior and inferior laryngeal nerves. SP- and CGRP-IR nerve fibers entered the epithelium through the basement membrane, ascended among the basal and ciliated cells, and reached under the epithelial junctional complex to terminate with varicosities. Furthermore, subsurface cistern-like structures or bouton en passant type synapse-like structures were observed among some varicosities of these nerve fibers and ciliated cells in the epithelial apical portion. On the other hand, VIP-IR nerve fibers entered through the basement membrane, and terminated with varicosities at the height of the middle portion of the subglottic epithelium. The varicosities of the VIP-IR nerve fibers were larger, and these varicosities had a greater number of synaptic vesicles than the SP- or CGRP-IR nerve fibers. After section of the bilateral superior and inferior laryngeal nerves, the SP- and CGRP-IR nerve fibers disappeared, while the VIP-IR nerve fibers were not affected. The density and distribution pattern of VIP-IR nerve fibers clearly differed from the SP- and CGRP-IR nerve fibers of sensory origin.(ABSTRACT TRUNCATED AT 250 WORDS)