Expression of MMPs and TIMPs in primary epithelial cell cultures of the upper aerodigestive tract seeded on the surface of a novel polymeric biomaterial

INTRODUCTION

Using standard cell biological and biochemical experimental approaches we were able to test the ability of a particular polymer construct to support the adhesion, proliferation, and the cellular acitivity of pharyngeal cells. The delicate balance between Matrix Metalloproteinases (MMPs) and their endogenous inhibitors (Tissue Inhibitor of MMPs, TIMPs) have a decisive function in the remodeling of the extracellular matrix during cellular ingrowth. Novel polymeric biomaterials may be useful to develop new therapeutic options in head and neck surgery.

METHODS

Primary cell cultures of the pharynx of Sprague-Dawley rats were seeded on the surface of a thermoplastic multi-block copolymer and on a polystyrene surface as control. Conditioned media of the primary cells was analyzed for MMPs and TIMPs. The MMP and TIMP expression was analysed by zymography and a radiometric enzyme assay.

RESULTS

No statistically significant differences in the levels of MMP-1, MMP-2, MMP-9 and TIMPs were detected between cells grown on the novel polymer surface versus control.

CONCLUSION

An appropriate understanding of the molecular machinery that regulates gene expression and cellular growth in tissue engineered constructs is the requirement for an optimal adaptation of biodegradable biomaterials to develop new therapeutic options in otolaryngology and head and neck surgery.

Post-hatching syrinx development in the zebra finch: an analysis of androgen receptor, aromatase, estrogen receptor ? and estrogen receptor ? mRNAs

In zebra finches, the vocal organ (syrinx) is larger in males than in females. Specific details about the mechanisms responsible for this dimorphism are not known, but may involve sex differences in steroid hormone action early in post-hatching development. The distribution of androgen receptor (AR), aromatase (AROM), estrogen receptor alpha (ERalpha), and estrogen receptor beta (ERbeta) mRNAs was examined at post-hatching days 3, 10 and 17. A low level of AR was equivalently expressed in the syrinx muscles of both sexes at all three ages. We detected no specific expression of AROM or ERalpha mRNAs. In contrast, ERbeta mRNA was detected in chondrocytes of the forming bone. The density of this expression increased with age as the chondrocytes hypertrophied, but did not differ between the sexes. Taken together, these data suggest that estrogens may act on cartilage/bone, and androgens may act on muscle fibers in early post-hatching development to influence syrinx morphology. However, the lack of a sex difference in steroid receptor mRNA expression in the syrinx suggests that, similar to the forebrain regions that control song, the interaction of androgens and estrogens with their receptors is not sufficient to induce full sexual differentiation of this organ.

Tobacco smoke induces persistent infection of Chlamydophila pneumoniae in HEp-2 cells

We examined tobacco smoke exposure and its effect on the life cycle of Chlamydophila pneumoniae (C. pneumoniae) in HEp-2, a human respiratory epithelial cell line. Using noncytotoxic concentrations of smoke medium, chlamydiae were grown in tissue culture and infectious particles were quantitated indirectly by immunocytometry of infected indicator cells. Chlamydial genome copy number was assessed with real-time polymerase chain reaction, and ultrastructure was examined by transmission electron microscopy. There was a significant reduction (56-64%; p<0.05) in the number of infectious elementary bodies following smoke exposure compared to untreated cultures. Under the same conditions, at late time points, smoke-exposed cultures showed significantly fewer chlamydial DNA copies (p<0.04). Moreover, smoke exposure induced large aberrant bodies that predominated within the inclusion. Following in vitro smoke exposure, alterations in the developmental cycle of C. pneumoniae included: inhibition of productive infection, reduced bacterial cell division, and formation of aberrant bodies. Thus, using this novel system, we were able to induce chlamydial persistence. Tobacco smoke exposure may represent a risk for establishment of a chronic reservoir of C. pneumoniae infection within respiratory epithelium.

Internalization of non-toxigenic Corynebacterium diphtheriae by cultured human respiratory epithelial cells

Although infection by Corynebacterium diphtheriae is a model of extracellular mucosal pathogenesis, and diphtheria is one of the most worried diseases, this microorganism can be associated also with invasive infections such as endocarditis, septic arthritis, and osteomyelitis. Invasive infections are usually caused by non-toxigenic C. diphtheriae strains. Over the last years severe pharyngitis/tonsillitis associated with the isolation of non-toxigenic C. diphtheriae have been described. Penicillin treatment failure of these infections could only partially be explained by penicillin tolerance of the causing strain. Thus, we examined the in vitro ability of non-toxigenic C. diphtheriae throat clinical isolates to adhere to, and enter human respiratory epithelial cells. Trasmission and scanning electron microscopy demonstrated intracellular C. diphtheriae in laryngeal (HEp-2 cells) and pharyngeal (Detroit D562 cells) tissue culture. Live intracellular bacteria were detectable up to 48 h post-infection. Using a variety of compound that act on eukariotic cell structures, the internalization of C. diphtheriae seems to occur via a zipper-like mechanism. It is likely that internalization of C. diphtheriae can be involved in throat colonization contributing to bacterial eradication failure and asymptomatic carriage.

Presence of dendritic cells, T lymphocytes, macrophages, B lymphocytes and glandular tissue in the human fetal larynx

OBJECTIVE

The laryngeal mucosa starts to be exposed to infectious agents immediately after birth. The course of laryngeal infections in young children differs significantly from that in adults. The first line of defense encountered by an inhaled infectious agent is the mucosa-associated immune system, which includes immunocompetent cells and secretory components. The cellular elements are partially organized in a typical morphological pattern known as mucosa-associated lymphoid tissue (MALT). Differences in the ability of young children and adults to react to a laryngeal infection raise the questions of whether and to what extent immunocompetent cells are already present in the larynx at birth. These questions were investigated in this study.

MATERIAL AND METHODS

Dendritic cells, T lymphocytes, B lymphocytes, macrophages and glands were examined and detected in an (immuno-)histological study of 8 fetal larynges (14th-22nd week of gestation).

RESULTS

Immunocompetent cells and glands were present mainly in the epi- and subglottic regions and ventricular folds, whereas the glottis was largely spared. The pattern of distribution was scattered and no organized MALT was seen.

CONCLUSION

Essential cell populations of a mucosa-associated immune system for the initiation of an immune response may exist in the human larynx at birth.

Non-random distribution of chromatid breaks in lymphocytes of laryngeal squamous cell carcinoma patients

The frequency and localization of mutagen-induced chromatid breaks in peripheral blood lymphocytes (PBLs) were investigated for association with squamous cell carcinoma (SCC) of the larynx. The case-control study was performed in 52 patients with laryngeal SCC and in 47 cancer-free controls. The analyses were based on the bleomycin sensitivity assay. The differences between cases and controls were estimated using Mann-Whitney U test and unconditional logistic regression. The total number of chromatid breaks in PBLs of patients was significantly higher compared with healthy controls (p<0.0001); the increase was observed in almost all chromosomal arms. In a number of chromosomal regions, the relative frequency of breaks was higher in patients; this increase was statistically significant for 1p22, 5q31, 6q23 and 10q24. The majority of sites with the increased proportion of breaks in patients were identified as regions containing loci involved in DNA repair, cell cycle regulation, suppressor genes and oncogenes. Revealing non-random distribution of chromatid breaks specifically associated with laryngeal SSC may be instrumental for defining regions involved in the etiology of this disease.

Escherichia coli O157:H7 adherence to HEp-2 cells is implicated with curli expression and outer membrane integrity

Escherichia coli (E. coli) has ability to express thin aggregative fimbriae, known as curli, on the cell surface. Previously, a few example of curli expression in serogroup O157:H7 of enterohemorrhagic E. coli (EHEC) were reported, compared to other E. coli groups. However, significance of curliation in the EHEC pathobiology has not been described well in the literature. A highly curliated O157:H7 strain was used in this study in order to elucidate role of curliation in EHEC adherence to cultured HEp-2 cells. The expression of curli in the EHEC isolate was consistent with strong positive indication of Congo-red (CR) binding and formation of clumps in the bottom of the tube containing Luria-Bertani (LB) broth when cultured overnight at 37 degrees C. A few CR-binding negative (CR-) colonies occurred spontaneously within the population of CR+ isolate. The CR+ EHEC showed massive aggregative adhesion pattern, whereas the spontaneous CR- strain showed typical localized adherence on HEp-2 cells. Electron microscopy confirmed highly curliated bacteria in the CR+ EHEC sample. Interestingly, the curliation disappeared in a msbB1 and msbB2 double mutant derived from the CR+ EHEC. These results suggest that the compromised outer membrane integrity caused by msbB mutations may abrogate curli production in the CR+ EHEC harbouring penta-acylated lipid A structure in their outer membrane.

Functional specialization of male and female vocal motoneurons

Vocal behaviors of African clawed frogs (Xenopus laevis) are produced by a single pair of muscles. This simplification, relative to other vertebrates, allows us to more easily determine how CNS motor pathways function to produce sex-specific songs. We describe here certain sexually differentiated properties of vocal motoneurons that are matched to male and female vocal demands. Both active and passive membrane properties differ between the sexes. Male motoneurons have lower input resistances and larger membrane capacitances than female motoneurons. Two distinct firing patterns are found, in different proportions, in males and females. The strongly adapting neurons that predominate in males initiate spikes at short, reliable latencies, whereas the weakly adapting motoneurons characteristic of females translate graded levels of depolarization into different firing rates. Low-threshold potassium currents (IKL) predominate in males. Hyperpolarization-activated cationic currents (IH) are found almost exclusively in males. Modeling results indicate that sex-typical active and passive properties can account for the occurrence of strongly and weakly adapting spike trains in the sexes. In particular, IKL seem to play an important role in determining the firing patterns of neurons. We suggest that these physiological differences facilitate transformation of synaptic inputs into male- and female-specific outputs that generate sexually distinct songs in vivo.

Geometrical deformation of vocal fold tissues induced by formalin fixation

OBJECTIVES/HYPOTHESIS

Many existing studies of vocal fold geometry are based on anatomical measurements made on histologically fixed laryngeal tissues using formalin. However, the validity of these geometric data is questionable because of the potentially significant tissue deformation associated with formalin fixation, particularly tissue shrinkage. Previous experiments have shown that valid geometric data may be obtained on vocal fold tissue samples quickly frozen with liquid nitrogen. Based on this finding, the present study attempted to quantify the geometric deformation of formalin-fixed vocal fold tissues with respect to quick-frozen tissues.

METHODS

Six freshly harvested canine larynges were quickly frozen with liquid nitrogen and sectioned at the mid-membranous coronal plane. Each larynx was thawed and divided into halves along the midsagittal plane, one of which was not fixed; the other was fixed with formalin, from which histological tissue sections were also prepared. Measurements of vocal fold geometry were made on digital images of mid-membranous coronal sections of the tissue samples, based on linear dimensions of vocal fold depth and thickness defined functionally for biomechanical applications.

RESULTS

Significant shrinkage of the vocal fold (particularly the vocal fold body) and considerable distortion of the vocal fold contour (particularly at the free edge) were observed for the formalin-fixed samples and the histological sections in comparison with the unfixed samples.

CONCLUSIONS

Results of the present study suggested that significant geometric artifacts are induced by conventional histological fixation of laryngeal tissues using formalin. These artifacts should be carefully considered for interpreting any vocal fold geometric data obtained through formalin fixation.

Effect of Candida albicans metabolite(s) on cellular actin

The present study describes experiments of the effect of Candida albicans metabolite(s) (arcsf) on cellular actin, and constitutes a continuation of our previous investigations regarding the effect of the fungus on actin. Western blot analysis of HEp2 cells exposed to arcsf or subfraction of arcsf (<100 kDa) revealed that the amount of soluble actin was decreased, and total actin increased, as compared to untreated cells. Transmission electron microscopy observations of HEp2 cells interacted with C. albicans or arcsf, and gold-labeled specifically for actin, revealed more intensive labeling, with labeled particles clustered in groups. Confocal laser scanning microscopy analysis has shown, as well, that exposure of HEp2 cells to the <100-kDa subfraction resulted in actin rearrangement, as did the unfractionated arcsf. Our results point to: (1) C. albicans metabolite(s) affects cellular actin by increasing the transition of soluble actin to the insoluble form; (2) the effect is associated with the subfraction of arcsf which is smaller than <100 kDa.

[Histology of the larynx]

The mucous membrane lining the interior of the larynx was studied in autopsy specimens taken from 21 infant larynxes, with ages ranging from 1 to 15 years. Only those larynxes in which the epithelial mucosal structures were preserved were set aside for study. A standard histological technique was applied. Paraffin sections were stained with haematoxylin-eosin, PAS, Masson's triple stain and orcine. The epithelium of the ventricles, ventricular bands and subglottis was found to be of respiratory type. On the vocal folds, the lining was non-keratinising squamous epithelium. These findings are consistent with those found in the literature. Findings that differed were as follows: the laryngeal surface of the epiglottis is classically described as having a respiratory type of epithelium, whereas we found it to be of non-keratinising stratified squamous type. The literature describes the epithelium of the ventricular bands as respiratory. While in our series we found stratified squamous in 56% and respiratory in 44%. Other findings are imprecise in the literature, and need definition; the finding of taste papillae in six cases without age correlation; and the richness of follicles in the lymphoid tissue at the epiglottis and ventricles of children aged more than 3 months.

A survey of the pattern of glandular distribution in the larynges of human infants

We studied the development of glandular structures and the pattern of distribution of serous and mucous-type glands in the larynges of 77 human infants obtained at autopsy. The subglottic larynx was subjected to quantitative and qualitative analysis, using an image binarization procedure. The areas of mucosa and inner space of the subglottic larynx tended to increase with age. The area occupied by the glands differed considerably in younger infants and the areas of total glands and serous-type glands increased with age. There was no correlation between the area of the mucous glands and age. These findings indicate that local immune function of the secretory glandular system in the larynx of human infants increases with advancing age.

[Optic coherent tomography: a new high-resolution technology of visualization of tissue structures. Part 1. Principle of the technique. Objects of OCT applications and technical decisions for their study]

The authors present a series of three papers dedicated to studies made in Russia in the field of optic coherent tomography (OCT), the latest noninvasive high-resolution technology of visualization of the structure of biological tissues. A group of medical specialists of different disciplines has been examined over 2,000 patients for 8 years of the use of an original class of the Russian OCT devices developed at the Institute of Applied Physics, Russian Academy of Sciences, and awarded a RF State Prize in the field of science and technology in 1999. The first paper discusses the basic aspects of OCT, the objects of study, and technical decisions for the clinical application of the technique. The paper shows a place of OCT, whose resolving capacity is close to the cellular level (approximately 10-15 microns), among classical methods for imaging biological tissues. The optical images of different types of normal tissues and the method of their identification are demonstrated. It has been found that different optical properties of investing tissues and dentin permit their tomographic differentiation by showing their regular bedded structure. The tomographic pattern of investing tissues is affected by their specific features, such as the type of the lining epithelium, its keratosic processes, and the architecture of the basilar membrane.

Epitope tagging of chromosomal genes in Salmonella

We have developed a simple and efficient procedure for adding an epitope-encoding tail to one or more genes of interest in the bacterial chromosome. The procedure is a modification of the gene replacement method of Datsenko and Wanner [Datsenko, K. A. & Wanner, B. L. (2000) Proc. Natl. Acad. Sci. USA 97, 6640-6645]. A DNA module that begins with the epitope-encoding sequence and includes a selectable marker is amplified by PCR with primers that carry extensions (as short as 36 nt) homologous to the last portion of the targeted gene and to a region downstream from it. Transformation of a strain expressing bacteriophage lambda red functions yields recombinants carrying the targeted gene fused to the epitope-encoding sequence. The resulting C-terminal-tagged protein can be identified by standard immuno-detection techniques. In an initial application of the method, we have added the sequences encoding the FLAG and 3xFLAG and influenza virus hemagglutinin epitopes to various genes of Salmonella enterica serovar Typhimurium, including putative and established pathogenic determinants present in prophage genomes. Epitope fusion proteins were detected in bacteria growing in vitro, tissue culture cells, and infected mouse tissues. This work identified a prophage locus specifically expressed in bacteria growing intracellularly. The procedure described here should be applicable to a wide variety of Gram-negative bacteria and is particularly suited for the study of intracellular pathogens.

Effects of carbonic anhydrase inhibition on the responsiveness of laryngeal receptors in cats to CO2

The effects of carbonic anhydrase inhibition on the responsiveness to CO2 of pressure-sensitive laryngeal receptors were examined in anaesthetised, paralysed cats. Laryngeal CO2-sensitive receptors from the superior laryngeal nerve were selected by their responsiveness to intralaryngeal pressure and to perfusion of solution equilibrated with 9% CO2. The carbonic anhydrase inhibitor, methazolamide, when given intralaryngeally at 10(-4) M, diminished or abolished the responses to the CO2-equilibrated solution in four of six pressure-sensitive receptors. Histochemical staining for carbonic anhydrase activity showed that the larynges perfused with methazolamide had diminished carbonic anhydrase activity, especially on the superficial layers of surface epithelium. Compared to untreated controls, when given intravenously (50 mg x kg(-1)) methazolamide diminished or abolished the responses to CO2 of five of the six fibres studied. Histochemical staining of these larynges showed no carbonic anhydrase reactivity at the sites of laryngeal receptors. These results suggest that the responses to CO2 of laryngeal pressure-sensitive receptors are dependent on the presence of carbonic anhydrase. Inhibition of laryngeal receptor carbonic anhydrase activity by methazolamide is more reliably achieved by systemic rather than by luminal administration.

Fascia Augmentation of the Vocal Fold: Graft Yield in the Canine and Preliminary Clinical Experience

INTRODUCTION

Glottal insufficiency resulting from vocal fold bowing, hypomobility, or scar is frequently treated by injection augmentation. Injection augmentation with fat, collagen, gel foam, polytef, and recently, fascia lata has been previously reported. Variable graft yield and poor host-tissue tolerance have motivated the continued search for an ideal graft substance.

STUDY DESIGN

A prospective trial of autologous fascia augmentation of the vocal cord in the human and in an animal model.

METHODS

Autologous fascia injection augmentation (AFIA) was evaluated in 8 canines and 40 patients at our institution between 1998 and 2000. The animal study compared graft yield from AFIA with autologous fat yield. The outcome measure was graft yield calculated from histological examination of larynges 12 weeks after injection augmentation. Clinical trial outcome measures included symptom surveys, acoustical voice analyses, and subjective voice assessments. Mean follow-up was 9 months.

RESULTS

In the canine larynx, the mean graft yield for AFIA was 33% (range, 5%-84%) compared with autologous lipoinjection (47%; range, 7%-96%; P =.57). Subjective improvement in vocal quality was reported by 95% of patients (38 of 40) after AFIA. Preoperative and postoperative voice analysis data were obtained from 26 patients. Subjective voice rating demonstrated a significant improvement after AFIA (P <.0001). Acoustical parameters of jitter, shimmer, noise-to-harmonic ratio, phonatory range, and degree unvoiced improved significantly (P <.05) in all patients after fascia augmentation.

CONCLUSIONS

Based on the animal study, we concluded that graft yields are excellent but variable for AFIA. The result is similar in variability and overall yield to autologous lipoinjection. Subjective and objective analyses of voice outcomes after AFIA are universally improved. Fascia appears to be an excellent alternative to lipoinjection in properly selected cases of glottic insufficiency.

[Resistance to Fas-mediated apoptosis in human papillomavirus type 16-immortalized human laryngeal epithelial cells after tumorigenesis]

Apoptosis plays an important role in such biological processes as multistep carcinogenesis. Human papillomavirus type 16(HPV16)-immortalized human epithelial cell lines are, for the most part, nontumorigenic in nude mice and useful for studying mechanisms involved in multistep carcinogenesis. We previously reported that HPV16-immortalized human laryngeal epithelial cell line HLEC16 formed tumors after treatment with 4-(methyl-nitrosamine)-1-(3-pyridyl)-1-butanone, and derived one tumorigenic cell line, HLEC16T. We compared sensitivity to Fas receptor-mediated apoptosis of nontumorigenic HLEC16 and tumorigenic HLEC16T. HLEC16 and HLEC16T expressed Fas protein (Fas) but not Fas-ligand (FasL) mRNA. We applied an anti-Fas monoclonal, antibody, CH11, to HLEC16 and HLEC16T, and monitored cell death. HLEC16T was found to be significantly less sensitive to CH11-mediated cell death that HLEC16. Western blot analysis showed no significant difference in levels of apoptosis-inducing protein, Bax, between HLEC16 and HLEC16T. Levels of apoptosis-inhibiting proteins Bcl-2 and Bcl-XL increased in HLEC16T. These results suggest that the inhibition of Fas-mediated apoptosis through apoptosis-inhibiting protein overexpression may promote tumorigenicity in HLEC16T.

A modified Spalteholz technique with preservation of the histology

The Spalteholz technique for producing clear macroscopic specimens was introduced 100 years ago, and is still in use today because it immediately provides transparent three-dimensional specimens. The classical clearing procedure with peroxide severely damages formalin-fixed tissue and inhibits further investigation on a histological level. We, therefore, wanted to make a transparent specimen by a modified Spalteholz method and chose the human larynx as an example of a large specimen. Its blood vessels were injected with gelatin, the specimen treated with acetone and peracetic acid and subjected to freeze substitution. After complete dehydration, benzyl benzoate and dimethylphthalate were used for impregnation. The cleared specimen satisfactorily revealed the laryngeal blood vessels and such structures as muscles, cartilage and the thyroid gland. The histology of the laryngeal glands, thyroid tissue, and infrahyoid muscle fibres was preserved. Tissue shrinkage became apparent with subsequent steps of the clearing procedure. We conclude that our modifications maintain the transparency of the specimen and allow histological investigation. The herein described technique thus constitutes an improvement of the classical Spalteholz technique.

The effect of thyroid stimulating hormone on the proliferation and viability of HEP-2 laryngeal cells in culture

The objective of this experiment was to study the effect of TSH on Hep-2 cells. A total of sixteen tubes (5 x 10(4) cells per tube) were divided into four equal groups (media alone (control), serum containing 0 TSH, 10.3 microliters/ml TSH, and 49 microliters/ml TSH). The supernatants and cells were collected at 24, 48, and 72 hours after incubation. The result show that TSH caused an increase in cell number after 24 hours in comparison to control media alone. Analysis of supernatants for cellular damage showed an increased pattern in MDA levels in serum exposed cells at 24, 48, and 72 hours. In contrast, MDA levels in TSH treated cells were similar at 24, 48, and 72 hours. The levels obtained at 48 and 72 hours were statistically (P < 0.05) lower than those obtained for control and serum treated or 0 TSH group. This observation suggests that TSH could provide a protective measure against membrane lipid peroxidation. Morphological evaluation of the cells at 24, 48, and 72 hours, suggests that TSH exposure did induce noticeable cellular injury and most adaptive responses observed were shape changes (round up), cellular detachment, and hyperchromatic nuclei (decrease in cell number).

Laryngeal cytological aspects in women with surgically induced menopause who were treated with transdermal estrogen replacement therapy

OBJECTIVE

To investigate the effects of estrogen replacement therapy (ERT) on laryngeal cytology in postmenopausal women.

DESIGN

Prospective open clinical trial.

SETTING

Outpatient menopausal clinic in the Department of Gynecology, University of Catania, Catania, Italy.

PATIENT(S)

Eighty-four healthy, surgically postmenopausal women, of whom 48 were treated with ERT and 36 were considered as a control group.

INTERVENTION(S)

Transdermal E(2) treatment by patches or gel, evaluation of laryngeal cytology with cytobrush by indirect laryngoscopy, and questionnaire for the voice history.

MAIN OUTCOME MEASURE(S)

Changes in cytologic aspects of laryngeal cells with respect to vaginal cytology by hematoxylin and eosin staining; subjective voice changes.

RESULT(S)

Sixty-seven women completed the study. Ten women from the ERT group and five from the control group dropped out because of the invasive laryngoscope method; two subjects in the control group were excluded because of pathologies of the vocal cord. Hematoxylin and eosin staining confirmed similar superficial-intermediate aspects of the cells between the laryngeal and the vaginal smears in ERT-treated women. In the control group, both smears showed aspects of atrophy-dystrophy. The ERT group had a subjectively better quality of voice than the control group.

CONCLUSION(S)

Our study confirms that the larynx is an estrogen target, as are vaginal cells. ERT may provide prevention and treatment of dystrophic pathologies of the vocal cords in postmenopausal women.

Laryngeal histologic findings in infants with palatal defects with or without craniofacial malformations

The objective of this study was to determine whether specimens from infants with palatal defects (PDs) with or without craniofacial malformations (CFMs) exhibit aberrant laryngeal histologic findings compared with specimens from normal infants. Ten laryngeal specimens from infants with PDs with or without CFMs were histologically compared with 7 laryngeal specimens defined as normal from the same collection. Both groups were similar in terms of demographics and airway manipulation. All infants were prelingual. Comparisons were made at 3 levels: supraglottic, glottic, and subglottic. Histologically, no significant differences in primary laryngeal structures were found between the PD with or without CFM group and the group defined as normal. Acquired and intubation-type injuries, such as inflammation, ulceration, capillary congestion, and scar tissue, were more prevalent and severe in the study group. The primary laryngeal histologic findings of specimens from individuals with PDs with or without CFMs do not differ substantially from those from normal individuals; however, individuals with PDs do appear to be somewhat more susceptible to intubation injury and other acquired laryngeal injury. Meticulous airway management is essential.

Soft tissue response in the rabbit larynx following implantation of LactoSorb (PLA/PGA copolymer) prosthesis for medialization laryngoplasty

This project is designed to provide initial data regarding the use of polylactic acid/polyglycolic acid (PLA/PGA) copolymer ("LactoSorb" [Walter Lorenz Corp]), an alloplastic, resorbable material, as a prosthesis in an animal model of vocal fold medialization. Fifteen New Zealand white rabbits were utilized for left medialization laryngoplasty with LactoSorb implants after undergoing left recurrent laryngeal nerve section. At 1, 3, 6, and 9 months, the rabbits were sacrificed and their larynges were evaluated both grossly and histologically for tissue response to, and resorption characteristics of the implant, tissue cellularity, maintenance of vocal fold medialization, and airway patency. Additionally, 4 rabbits were used as controls, implanted with silicone rubber medialization implants, and sacrificed at 9 months for comparison. One rabbit underwent no surgery and was likewise used as a control. Grossly, no airway obstruction was noted, and no extrusions of the implants occurred. The LactoSorb implant maintained medialization in each group of sacrificed rabbits. Histologic findings revealed a very discrete, fibrous capsule around the implant in the 1- and 3-month rabbits, and the LactoSorb was still grossly visible. At 6 months, the thin fibrous capsule partially remained; at 9 months, the capsule was no longer evident, and the implant was no longer grossly visible. Endoscopic findings at the time of sacrifice in those rabbits implanted with silicone rubber included grossly patent airways with maintenance of medialization. In the rabbits implanted with silicone rubber, the histologic findings are similar to those described elsewhere. LactoSorb, because of its intermittent resorption rate, could offer an ideal alternative to currently utilized temporary, or resorbable, materials, and as such will hopefully prove an invaluable tool in the laryngologist's treatment planning and surgical repair of the patient with a paralyzed vocal fold.

[Effects of calcium on HPV16 gene transcription in cultured laryngeal epithelial cells]

Human papillomavirus (HPV) gene transcription is closely linked to the differentiation status of infected epithelial cells. A variety of physiological agents, including calcium, regulates the differentiation of cultured epithelial cells. The expression of cytokeratin No.13 (CK13) can be used as a marker for differentiation in cultured laryngeal epithelial cells (HLEC cells). The purpose of this study is to examine the effects of calcium on CK13 expression and HPV16 gene transcription in HLEC cells. We analyzed two types of HPV16-containing HLEC cells: HPV 16-immortalized HLEC cells (HLEC16 cells) and HPV16-positive (infected) cultured laryngeal papilloma cells (HLP16 cells). In the HLEC16 cells, the viral genes were integrated into the host cell chromosomes, while the HLP16 cells contained extra-chromosomal viral genes. The effects of increasing calcium concentrations on CK13 expression were then evaluated using immunocytochemistry. Both the HLP16 and the HLEC16 cells responded to an increased calcium concentration by inducing CK13 expression. In HLP16 and HLEC16 cells, the CK13 expression was undetectable at low calcium concentrations (0.1 mM) but became clearly detectable at high calcium concentrations (1.0 mM). The level of viral RNA was elevated in HLP16 cells with added calcium (1.0 mM) but was similar in HLEC16 cells grown in either low (0.1 mM) or high (1.0 mM) calcium concentrations. These results suggest that a calcium-induced differentiation results in the up-regulation of HPV16 gene transcription in HLP16 cells. The integration of viral gene into the host cell chromosomes may be an important determinant for the differentiation-independent transcription of HPV16 genes.

Alcian blue pyridine variant--a superior alternative to alcian blue 8GX: staining performance and stability

We compared the staining performance, dye content, solubility, and visual absorption maximum of two batches of alcian blue pyridine variant and of five batches of alcian blue 8GX (C.I. 74240). Whenever possible, we also compared results to those obtained with the same dye batches produced at an earlier date to provide information concerning dye stability. Both alcian blue pyridine variant batches were of high dye content, stable, of satisfactory solubility, and performed well in both the routine Mowry mucin stain and in the critical electrolyte concentration (CEC) stain. Of the five alcian blue 8GX samples, some were also of appropriate dye content, were sufficiently stable, and gave good staining in the two procedures. Two batches, however, were unstable, and three batches were unsatisfactory in staining performance and solubility in the CEC stain. Consequently alcian blue pyridine variant is a superior substitute for alcian blue 8GX.

Contribution of supraglottal mechanoreceptor afferents to respiratory-related evoked potentials in humans

We used the global field power (GFP) to estimate the magnitude and timing of activation of the somatosensory cortex by respiratory mechanoreceptor afferents in normal humans in response to brief, negative oral pressure pulses applied at the onset of inspiration. We compared responses before (test) and after insertion of a laryngeal mask airway (LMA) that prevented supraglottal airway receptors from sensing the applied stimulus. Evoked potential responses without supraglottic stimulation were smaller, with delayed or missing features, than those with all receptors stimulated. Supraglottic receptors contribute about one-half of the GFP summed over the 100 ms poststimulus, and subglottal receptors, including those in the larynx, provide a GFP response approximately 38% above baseline. The most obvious difference between test and LMA responses occurred at 55 ms on average, when the LMA GFP lacked activation features seen in the test condition. We conclude that mechanoreceptors above the larynx are responsible for a major portion of the midlatency afferent information arriving at the somatosensory cortex in response to applied pressure pulses.