Fibrin with Laminin-Nidogen Reduces Fibrosis and Improves Soft Palate Regeneration Following Palatal Injury

This study aimed to analyze the effects of fibrin constructs enhanced with laminin-nidogen, implanted in the wounded rat soft palate. Fibrin constructs with and without laminin-nidogen were implanted in 1 mm excisional wounds in the soft palate of 9-week-old rats and compared with the wounded soft palate without implantation. Collagen deposition and myofiber formation were analyzed at days 3, 7, 28 and 56 after wounding by histochemistry. In addition, immune staining was performed for a-smooth muscle actin (a-SMA), myosin heavy chain (MyHC) and paired homeobox protein 7 (Pax7). At day 56, collagen areas were smaller in both implant groups (31.25 ± 7.73% fibrin only and 21.11 ± 6.06% fibrin with laminin-nidogen)) compared to the empty wounds (38.25 ± 8.89%, p < 0.05). Moreover, the collagen area in the fibrin with laminin-nidogen group was smaller than in the fibrin only group (p ˂ 0.05). The areas of myofiber formation in the fibrin only group (31.77 ± 10.81%) and fibrin with laminin-nidogen group (43.13 ± 10.39%) were larger than in the empty wounds (28.10 ± 11.68%, p ˂ 0.05). Fibrin-based constructs with laminin-nidogen reduce fibrosis and improve muscle regeneration in the wounded soft palate. This is a promising strategy to enhance cleft soft palate repair and other severe muscle injuries.

Muscle fibrosis in the soft palate: Delivery of cells, growth factors and anti-fibrotics

The healing of skeletal muscle injuries after major trauma or surgical reconstruction is often complicated by the development of fibrosis leading to impaired function. Research in the field of muscle regeneration is mainly focused on the restoration of muscle mass while far less attention is paid to the prevention of fibrosis. In this review, we take as an example the reconstruction of the muscles in the soft palate of cleft palate patients. After surgical closure of the soft palate, muscle function during speech is often impaired by a shortage of muscle tissue as well as the development of fibrosis. We will give a short overview of the most common approaches to generate muscle mass and then focus on strategies to prevent fibrosis. These include anti-fibrotic strategies that have been developed for muscle and other organs by the delivery of small molecules, decorin and miRNAs. Anti-fibrotic compounds should be delivered in aligned constructs in order to obtain the organized architecture of muscle tissue. The available techniques for the preparation of aligned muscle constructs will be discussed. The combination of approaches to generate muscle mass with anti-fibrotic components in an aligned muscle construct may greatly improve the functional outcome of regenerative therapies for muscle injuries.

Injection Snoreplasty: Investigation of Alternative Sclerotherapy Agents

OBJECTIVE: Palatal sclerotherapy with sodium tetradecyl sulfate (“injection snoreplasty”) was recently introduced as a safe and effective treatment for primary snoring. However, multiple other sclero-therapy agents also have excellent safety records and documented efficacy in the head and neck. Widely available and inexpensive agents were evaluated as potential palatal sclerosing agents for the treatment of snoring.

STUDY DESIGN AND SETTING: A described canine palatal flutter model was used to evaluate the palatal stiffening efficacy of ethanol, doxycycline, and hypertonic saline in comparison to 3% sodium tetradecyl sulfate (STS) and a negative control (normal saline). Based on the animal study results, a human pilot study with ethanol was performed with subjective and objective data.

RESULTS: Ethanol was found to be equally effective as 3% STS in the canine model. Doxycycline was effective but less so, and hypertonic saline was comparatively ineffective. Palatal injection in human patients with 50% ethanol was found to produce equivalent subjective and objective snoring efficacy and equivalent pain and recovery time compared with 3% STS. However, there was a higher rate of transient palatal fistula with ethanol. CONCLUSIONS AND SIGNIFICANCE: Injection snoreplasty with 50% ethanol is equally efficacious compared with 3% STS. There could be a higher fistula rate with the use of ethanol, although this complication has been self-limited and transient in every case.

Successful Treatment of Autophonia with Botulinum Toxin: Case Report

Objectives:

We sought to treat autophonia due to a patulous eustachian tube using botulinum toxin.

Methods:

Because we assumed that the patulous eustachian tube was caused by abnormal activity of paratubal muscles (tensor and levator veli palatini muscles and salpingopharyngeus muscle), paralysis was performed via injection of botulinum toxin type A in a 45-year-old female professional musician who had had chronic unilateral autophonia for 20 years. In addition to a patient interview, an endoscopic examination of the nasopharynx (posterior rhinoscopy), ear microscopy, and impedance audiometry were performed to verify the diagnosis and the outcome after treatment.

Results:

The autophonia disappeared 1 week after treatment. Normalized tympanic ventilation was verified by impedance audiometry after 8 weeks. The period of symptom relief was 9 months.

Conclusions:

The administration of botulinum toxin type A provides a new option in the treatment of patulous eustachian tube. The reliability of this method and the effect of repeated injections remains to be proved in future studies.

Injections of Local Anesthetics into the Pharyngeal Region Reduce Trapezius Muscle Tenderness

BACKGROUND

Neck pain is a frequent reason for seeking medical advice. Neuroanatomical findings suggest a close connection between the pharynx and the trapezius region. Irritation of the pharynx may induce tenderness of this area. Specific tender points, called neck reflex points (NRPs), can be identified here with high reproducibility. We hypothesized that therapeutic local anesthesia (TLA; or neural therapy, NT) in the pharyngeal region can reduce tenderness in patients with therapy-resistant neck pain.

PATIENTS AND METHODS

17 consecutive female patients with chronic cervical pain and positive trapezius NRPs received bilateral injections of 0.5 ml 1% procaine into the palatine velum. The NRPs were assessed using a 3-level pain index (PI = 0, 1, or 2) before and 3-5 min after each injection.

RESULTS

We found a significant reduction in tenderness of the NRP of the trapezius region (NRP C7) immediately after TLA/NT. 30 positive NRPs were found before therapy and only 13 after therapy (p < 0.01). The average PI of the NRP C7 was 1.24 ± 0.77 before and 0.35 ± 0.59 after therapy (right side), and 1.34 ± 0.59 before and 0.59 ± 0.69 after therapy (left side). The pre- and post-therapy PI values were significantly different on both the right and left sides of the trapezius region (p < 0.01). No adverse effects were observed.

CONCLUSIONS

Pharyngeal irritation may induce and maintain therapy-resistant cervical pain in patients with chronic pharyngeal disease. These patients could benefit from remote TLA/NT injections in the pharyngeal region.

Palatal sclerotherapy for the treatment of intermittent dorsal displacement of the soft palate in 51 standardbred racehorses

This retrospective study evaluated the efficacy and side effects of palatal sclerotherapy in standardbred racehorses suspected to have intermittent dorsal displacement of the soft palate (IDDSP). Fifty-one horses were treated with multiple endoscopically guided injections of 3% sodium tetradecyl sulfate in the soft palate. Two groups were identified: those that had respiratory noises during exercise (n = 27) and those that did not (n = 24). Treatment was well-tolerated. Furthermore, horses significantly reduced their racing times for the last 400 m compared with their times before treatment and even when their times were compared to the mean times for horses in the same race. In conclusion, palatal sclerotherapy appears to be a suitable alternative therapeutic option for horses suspected to have IDDSP.

Palatal sclerotherapy: a potentially useful treatment of intermittent dorsal displacement of the soft palate in juvenile standardbred racehorses

This study was aimed at evaluating the tolerability and the efficacy of palatal sclerotherapy in juvenile standardbred racehorses with easily audible "snoring-like" respiratory noises suspected to be the result of intermittent dorsal displacement of the soft palate. The palate of 8 horses was injected with sodium tetradecyl sulfate under videoendoscopic guidance. Palatal sclerotherapy resulted in resolution of the respiratory noise in 7 horses, improvement of performance in 6 horses, and mild side effects in only 3 horses. This preliminary study suggests that palatal sclerotherapy is a safe, repeatable, inexpensive, and promising technique that should be considered as an alternative to existing treatments of intermittent dorsal displacement of the soft palate.

Treatment of habitual snoring with botulinum toxin: a pilot study

The objective of this study was to investigate whether injections of botulinum toxin into the soft palate reduce snoring in a subgroup of patients that present an active process causing habitual snoring. The study was conducted in eight patients with habitual snoring but without evidence of obstructive sleep apnea. Polysomnography was performed for diagnostic purposes and to monitor sleep quality before and after treatment. The patients and their partners completed a questionnaire before and after treatment. Recordings of snoring noise before and after treatment were evaluated on a visual analog scale by a blinded assessor. Doses of 20 U of botulinum toxin type A (Dysport) were injected unilaterally into the muscles of the soft palate. Snoring was reduced in eight cases. The patients reported no major adverse effects. These results justify further studies of botulinum toxin therapy in patients with habitual snoring. The scheme presented for injections of botulinum toxin into the levator veli palatini muscle provides a rational basis for the design of such studies. Therapy with botulinum toxin for habitual snoring is safe, non-invasive, easy to perform, fully reversible, and thus warrants investigation under placebo-controlled, double-blind conditions. This treatment is appropriate for a disorder that is of paramount social importance but does not pose a medical threat to the individuals affected.

Ciprofloxacin-induced palatal tremor

We describe an 84-year-old man with an unusual clinical presentation of palatal tremor in association with ciprofloxacin treatment. The patient had rhythmical movements not only of the soft palate but also of the face and trunk. Complete resolution of the symptoms occurred 2 days after discontinuation of ciprofloxacin and administration of sodium valproate. This is the first reported case of palatal tremor secondary to the use of ciprofloxacin.

Extent and Localization of Changes in Upper Airway Caliber with Varying Concentrations of Sevoflurane in Children

Background

Previous studies in humans suggest that inhibition of upper airway muscle activity is independent of the dose of inhalational anesthesia. Whether a dose-independent relation applies to changes in airway caliber is unknown. The authors sought to evaluate the configurational changes that lead to upper airway narrowing during inhalational anesthesia with sevoflurane and to determine whether these changes are dose dependent within a clinically relevant dose range.

Methods

Fifteen children undergoing elective magnetic resonance imaging of the brain were studied. Magnetic resonance images of the upper airway were acquired at sevoflurane concentrations of 0.5, 1.0, and 1.5 minimum alveolar concentration (MAC), administered in random sequence. At least 15 min was allowed for equilibration of inspired and alveolar partial pressures of sevoflurane. Images were acquired in early expiration at the level of the soft palate, base of the tongue, and tip of the epiglottis. Airway cross-sectional area (CSA), anteroposterior, and transverse dimension were determined using image-analysis software.

Results

At each anatomical level, pharyngeal CSA decreased progressively with increasing depth of sevoflurane anesthesia (P &lt; 0.001). Increasing the sevoflurane concentration from 0.5 to 1.0 MAC reduced airway CSA by 13-18%, and a further increase to 1.5 MAC resulted in an overall 28-34% reduction in CSA. The reduction in CSA was predominantly due to a decrease in anteroposterior dimension.

Conclusions

Increasing the depth of sevoflurane anesthesia resulted in a relatively uniform reduction in pharyngeal caliber at each anatomical level studied. The effect of sevoflurane on upper airway caliber is dose dependent.

Histologic effects of injection snoreplasty and radiofrequency in the rat soft palate

OBJECTIVE

This study was undertaken to compare the effects of radiofrequency and injection snoreplasty on the histological structure of the soft palate in an animal model.

STUDY DESIGN AND SETTING

This is a blinded, controlled histologic evaluation of rat soft palates that underwent separate palatal interventions. Fifty rats were divided into 5 groups of 10 rats (Group 1 = injection snoreplasty [IS], Group 2 = IS + steroid, Group 3 = saline injection, Group 4 = radiofrequency ablation [RFA], and Group 5 = no intervention). The animals were sacrificed after 24 hours, 1 week, 3 weeks, and 5 weeks. Then the soft palates were subjected to histological analysis.

RESULTS

Histological analysis demonstrated normal remucosalization in all specimens, with fibrosis increased in Group 1. Interstitial edema was minimal in Group 2. Keratinization was most apparent in Group 4.

CONCLUSION

Radiofrequency and injection snoreplasty stiffen the rat soft palate compared with controls.

Botulinum toxin is effective and safe for palatal tremor: a report of five cases and a review of the literature

Palatal tremor (formerly palatal myoclonus) is an extremely rare, but potentially treatable cause, of objective tinnitus. The tinnitus is thought to be secondary to rhythmic involuntary movements of the soft palate. Its aetiology is variable and it remains difficult to treat. Many different medical and surgical remedies have been tried but none have demonstrated reproducible success. Botulinum toxin has been used in sporadic cases and seems to produce good results. Ten patients with palatal tremor have presented to this department over the last three years. After discussion with the patients with regard to the management of this condition and possible complications, five opted for botulinum toxin therapy and five declined further intervention. Clinical diagnosis was made on the confirmation of soft palate movements synchronous with an audible clicking noise. Five patients underwent botulinum toxin injection into the insertion of the levator and tensor veli palatini muscles. Of the five that were treated with toxin, four showed complete resolution of symptoms after a course of treatment. Only one patient reported transient side effects. This would suggest that botulinum toxin is a safe and effective first line treatment for palatal tremor.

Immunohistochemical evaluation of metallothionein in palatal mucosal cells of mice treated with 4NQO

OBJECTIVE

Metallothionein (MT) may play a preventive role in various carcinogenic process. 4NQO is an alkaline compound and potent mutagen that causes the formation of DNA adducts. The purpose of this study was to evaluate the immunoexpression of MT in palatal cells of mice submitted to the carcinogen 4NQO.

STUDY DESIGN

C57BL/6 mice received applications of 4NQO to palate for periods of 8, 16, 20 and 24 weeks (experimental group). A control group received only applications of propylene glycol for the same periods. Subsequently animals of experimental and control groups were sacrificed and the palate was histologically analysed and MT immunohistochemistry performed.

RESULTS

Although morphological atypical features were scant, the expression of MT was higher in the experimental group in comparison to controls. There was an amplified induction of MT expression in oral epithelium of mice treated by 4NQO.

CONCLUSION

These results suggest that MT may act as an endogenous defensive factor against 4NQO in early phases of oral carcinogenesis.

Radiofrequency versus injection snoreplasty in simple snoring

OBJECTIVE

To compare the efficacy and tolerance of controlled temperature radiofrequency (RF) and injection snoreplasty (IS) for the treatment of simple snoring.

STUDY DESIGN

The study was a nonrandomized, prospective study conducted on 70 simple snorers. Efficacy of the operations was subjectively evaluated by the bed partners and after 6 weeks of the last treatment. Tolerance was evaluated by the patient during first 10 postoperative days. Postoperative pain and discomfort level were assessed.

RESULTS

Satisfaction in terms of snoring severity was reported by 87.5% of the cases with RF and by 76.7% of the patients with IS. Discomfort levels also were similar for both groups

CONCLUSIONS

Controlled-temperature RF and IS were both effective on snoring and well tolerated by the patients. This allows retreatments if necessary.

Tissue-dissolution capacity and dentin-disinfecting potential of calcium hydroxide mixed with irrigating solutions

OBJECTIVE

The goal of this study was to compare the tissue-dissolution potential and antibacterial effectiveness of a conventional Ca(OH)(2)/saline paste with equivalent Ca(OH)(2)/NaOCl and Ca(OH)(2)/chlorhexidine digluconate medications.

STUDY DESIGN

Tissue specimens were obtained from freshly dissected pig palates. Tissue pieces of similar form and weight were incubated in air-tight containers with Ca(OH)(2) pastes or solutions proper for up to 7 days. Antimicrobial testing was performed in dentin blocks infected with Enterococcus faecalis. Medicated, sealed dentin specimens were incubated for 1 and 5 days, and bacterial growth was tested at different dentin depths.

RESULTS

Up to day 4, the Ca(OH)(2)/irrigating solution mixtures dissolved tissue more effectively than the conventional Ca(OH)(2)/saline paste. After 7 days, however, no statistically significant differences were found between the saline and hypochlorite mixtures, but the Ca(OH)(2)/chlorhexidine medication was significantly less effective. Dentin block disinfection was quicker and more thorough with the Ca(OH)(2)/chlorhexidine or the Ca(OH)(2)/NaOCl than with the Ca(OH)(2)/saline paste.

CONCLUSION

Ca(OH)(2)/irrigant mixtures under investigation appear more advantageous than the conventional Ca(OH)(2)/saline mixture, and merit further investigation in a clinical study.

Effect of increasing depth of propofol anesthesia on upper airway configuration in children

BACKGROUND

The upper airway tends to be obstructed during anesthesia in spontaneously breathing patients. The purpose of the current study was to determine the effect of increasing depth of propofol anesthesia on airway size and configuration in children.

METHODS

Magnetic resonance images of the upper airway were obtained in 15 children, aged 2-6 yr. Cross-sectional area, anteroposterior dimension, and transverse dimension were measured at the level of the soft palate, dorsum of the tongue, and tip of the epiglottis. Images were obtained during infusion of propofol at a rate of 50-80 microg.kg-1.min-1 and after increasing the depth of anesthesia by administering a bolus dose of propofol and increasing the infusion rate to 240 microg.kg-1.min-1.

RESULTS

Overall, the cross-sectional area of the entire pharyngeal airway decreased with increasing depth of anesthesia. The reduction in cross-sectional area was greatest at the level of the epiglottis (24.5 mm2, 95% confidence interval = 16.9-32.2 mm2; P < 0.0001), intermediate at the level of the tongue (19.3 mm2, 95% confidence interval = 9.2-29.3 mm2; P < 0.0001), and least at the level of the soft palate (12.6 mm2, 95% confidence interval = 2.7-22.6 mm2; P < 0.005) in expiration and resulted predominantly from a reduction in anteroposterior dimension. The airway cross-sectional area decreased further in inspiration at the level of the epiglottis. The narrowest portion of the airway resided at the level of the soft palate or epiglottis in the majority of children.

CONCLUSION

Increasing depth of propofol anesthesia in children is associated with upper airway narrowing that occurs throughout the entire upper airway and is most pronounced in the hypopharynx at the level of the epiglottis.

Voltage-gated channels involved in taste responses and characterizing taste bud cells in mouse soft palates

Taste bud cells (TBCs) on soft palates differ from those on tongues in innervation and chemosensitivity. We investigated voltage-gated channels involved in the taste responses of TBCs on mouse soft palates under in-situ tight-seal voltage/current-clamp conditions. Under the cell-attached mode, TBCs spontaneously fired action currents, which were blocked by application of 1 microM TTX to TBC basolateral membranes. Firing frequencies increased in response to taste substances applied to TBC receptor membranes. Under the whole-cell clamp mode, as expected, TBCs produced various voltage-gated currents such as TTX-sensitive Na+ currents (INa), outward currents (Iout) including TEA-sensitive and insensitive currents, inward rectifier K+ currents (Iir), and Ca2+ currents including T-type, P/Q-type, and L-type Ca2+ currents. We classified TBCs into three types based on the magnitude of their voltage-gated Na+ currents and membrane capacitance. HEX type (60% of TBCs examined) was significantly larger in Na+ current magnitude and smaller in membrane capacitance than LEX type (23%). NEX type (17%) had no Na+ currents. HEX type was equally distributed within single taste buds, while LEX type was centrally distributed, and NEX type was peripherally distributed. There were correlations between these electrophysiological cell types and morphological cell types determined by three-dimensional reconstruction. The present results show that soft palate taste buds contain TBCs with different electrophysiological properties, and suggest that their co-operation is required in taste transduction.

Case of essential palatal tremor: atypical features and remarkable benefit from botulinum toxin injection

We describe a 21-year-old man with essential palatal tremor. The patient had rhythmic contractions not only of tensor veli palatini but also of facial, lingual, temporalis, pharyngeal, and neck muscles. He had some voluntary control of palatal tremor and ear clicks. He was treated with 5 units of botulinum toxin-A (BOTOX) injected into each tensor veli palatini, and had complete resolution of all the symptoms.

The glossopharyngeal nerve as a novel pathway in immune-to-brain communication: relevance to neuroimmune surveillance of the oral cavity

Glossopharyngeal afferents may be the neural channel by which immune challenge of the posterior oral cavity conveys information to the brain. If this is the case, then bilateral transection of the glossopharyngeal nerves (GLOx) should disrupt this communication. Injection of lipopolysaccharide (LPS) or interleukin (IL)-1beta into the soft palate (ISP) of sham-operated rats induced a dose-related febrile response. GLOx significantly attenuated the febrile response induced by ISP injection of both LPS and IL-1beta. In contrast, GLOx did not affect the febrile response when LPS or IL-1beta were injected intraperitoneally, indicating that the effect of GLOx is not systemic. These results provide experimental evidence for a novel neural pathway for immune-to-brain communication.

Palatal myoclonus: report of two cases

We describe two cases of palatal myoclonus (PM), one essential and another secondary to a stroke. Case 1: a 64 years old female who developed clicking sounds in both ears after a stroke and three years later on noticed a progressive involuntary movement of the throat associated with rhythmic contractions of the soft palate, muscles of tongue and throat. MRI showed an ischemic area in brainstem. The patient had a partial response to the use of sumatriptan 6 mg subcutaneously. Case 2: a 66 years old female who began with ear clicking at left ear that worsed slowly associated with tinnitus and arrhythmic movements of soft palate and an audible click at left ear. Brain MRI was normal; audiometry showed bilateral neurosensory loss. She was prescribed clonazepan 1 mg daily with complete recovery. Primary and secondary palatal myoclonus share the same clinical features but probably have different pathophysiological underlying mechanisms.

[Effect of carnosine on the morphofunctional state of mucosal cells of the soft palate of rats in staphylococcal infection]

The influence of carnosine on the morphofunctional state of mucosal cells of the soft palate of rats in experimental staphylococcal infection has been studied. Morphological changes in muscular and connective tissue cells of the mucosa of the soft palate of rats have been found to occur. The suppressive effect of carnosine with respect to the pathogen and its positive influence on the processes of the regeneration of eukaryotic tissues.

Glycosaminoglycan biosynthesis during 5-fluoro-2-deoxyuridine-induced palatal clefts in the rat

The biosynthesis and hydration of glycosaminoglycans (GAG) has been implicated in the generation of palatal shelf-elevating force(s) in mammals, although the nature of the palatal shelf extracellular matrices during cleft palate formation remains poorly understood. This study quantifies the GAG composition in the palatal shelves of Wistar rat fetuses at various periods of palatogenesis where clefts were induced experimentally using 5-fluoro-2-deoxyuridine (FUDR). For both normal and cleft palatal shelves, hyaluronan, heparan sulphate and chondroitin-4-sulphate were detected but not dermatan sulphate or chondroitin-6-sulphate. Throughout the period of cleft development studied, the total amount of GAG was significantly decreased (by approx. 30%) compared with normal development, this decrease being particularly marked at a time equivalent to post-elevation during normal development (approx. 75%). Furthermore, and unlike normal palatogenesis, no significant differences were recorded between the anterior and posterior parts of the palatal shelves during cleft formation. As for normal palatogenesis, however, the percentages of each GAG were not altered at any stage. The findings are consistent with the view that suppression of GAG biosynthesis is related to the development of cleft palate in FUDR-treated rat fetuses and can therefore be interpreted as providing evidence of a role for the mesenchymal glycoconjugates in shelf elevation during normal palatogenesis.

Vertical development of the secondary palate in hamster embryos following exposure to 6-mercaptopurine

Cellular aspects of vertical development of the secondary palate were examined in control and 6-mercaptopurine (6MP)-treated hamster embryos. Cross-sectional area of the palatal shelf was measured and the numbers of both epithelial and mesenchymal cells counted. Also, in 6MP-treated palates the damaged mesenchymal cells, characterized by the presence of dense bodies, were counted. DNA synthesis in both control and treated fetuses was measured by 3H-thymidine incorporation. The results indicated that both the shelf area and cell numbers increased with age in control and 6MP-treated palates. However, in controls the mesenchymal cell density and DNA synthesis showed two peaks that were absent following 6MP treatment. Unlike controls, in treated embryos the damage to mesenchymal cells became increasingly pronounced between days 10:00 and 10:12 but subsided by day 11:00 of gestation. It is suggested that a major force in the development of the initial primordia and early vertical development of the palatal shelf may be provided by a spurt of DNA synthesis in the mesenchymal cells resulting in their increased number. After 6MP treatment, depression of DNA synthesis and consequent reduction in the mesenchymal cell number and density followed by cell damage lead to retardation in the vertical development of the palatal shelves.

Effects of chlorcyclizine-induced glycosaminoglycan alterations on patterns of hyaluronate distribution during morphogenesis of the mouse secondary palate

Chlorcyclizine (CHLR) enhances the degradation of hyaluronate (HA) into smaller molecular weight pieces with no effect on its synthesis. Administration of CHLR to pregnant CD-1 mice on gestational days 10.5, 11.5 and 12.5 results in 100% cleft palate in the fetuses. The caudal two thirds of the palatal shelves are reduced in size and unable to reorient in vitro, while anterior shelf regions are relatively unaffected. Alcian blue staining combined with specific enzymic digestion was used to identify HA in sections of CHLR-treated shelves. With the aid of computer-assisted image subtraction the patterns of HA distribution across the tissue section were objectively identified. Anterior, posterior and presumptive soft palatal shelf regions were examined at gestational days 13.25, 13.5, 13.75 and 14.5. Acquisition of a normal pattern of HA distribution was delayed by about 24 h, as compared to untreated specimens in all three shelf regions. The posterior and soft regions, comprising the caudal two thirds of the shelf, also showed pronounced shape change. These regions only displayed normal curvature of the nasal surface when a normal pattern of HA distribution was attained. These results suggest that, for the caudal two thirds of the palatal shelf, normal shape and the ability to remodel are linked to the molecular configuration of HA and to a specific pattern of HA distribution.

The effect of diphenylhydantoin upon degradation of sulphated macromolecules in cat palatal mucosa in vitro

The effect of diphenylhydantioin (DPH) upon the degradation of in vivo [35S]-sulphate-labelled proteoglycans was studied in cat palatal mucosa during organ culture. 8-week-old cats were injected intraperitoneally with [35S]-sulphate and 24 hours later the palatal mucosa was taken to organ culture. The release of radioactivity into the culture medium was taken as a measure of degradation of sulphated macromolecules, presumably proteoglycans, and the release of hydroxyproline as an indicator for collagen degradation. A parallel decrease in the release of radioactivity and in the release of hydroxyproline was observed when the culture was done in the presence of DPH (20 mg/l). Chromatography of the culture medium upon Sephadex G-25 revealed that the reduced release of radioactivity was due to a reduction of macromolecular degradation products leaving the amounts of free sulphate in the medium unchanged. The results were interpreted using a two compartment theory for proteoglycan degradation, extracellular breakdown of the protein core resulting in the production of macromolecular degradation products and intracellular lysosomal degradation resulting in free sulphate as the identifiable product. The results indicate that DPH inhibited the extracellular enzymatic degradation of proteoglycans without influencing their intracellular degradation.

The effect of diphenylhydantoin upon enzyme release in relation to collagen degradation in cat palatal mucosa during organ culture

The effect of diphenylhydantoin (DPH) on degradation of collagen was studied during 10 days in organ culture of cat palatal mucosa by measuring the release of hydroxyproline to the culture medium. In parallel, the activities of beta-glucuronidaase and lactate dehydrogenase (LDH) as markers for lysosomal and cytosokic enzymes, respectively, were registered in the tissues and in the culture medium and the glucose consumption was also measured. DPH caused a 36% inhibition of the cumulative release of hydroxyproline to the medium. The activities in the media of beta-glucuronidase and LDH showed a 23% and 30% reduction, respectively. The glucose consumption was unaltered by the drug. The results show that one way by which DPH may interfere with collagen degradation is by blocking enzyme release from the cells.

Influence of zinc on onset and progression of oral carcinogenesis in rats

Three-week-old female rats were fed 0.09 (zinc-deficient), 0.77 (zinc-adequate) or 3.98 (zinc-supplemented) mmol zinc/kg diet in three experimental groups and the palatal mucosa was painted with the water-soluble carcinogen 4-nitroquinoline N-oxide (4NQO) three times a week for 20 weeks. The zinc-supplemented diet seemed to retard the induction of carcinogenesis, whereas a low-zinc diet had the opposite effect. Once initial cellular changes had been induced the supplementary zinc seemed to accelerate their further advancement. Zinc-deficiency in animals fed a copper/zinc low-zinc diet was reflected in the plasma and liver zinc levels as well as in the copper/zinc ratio. The development of cancer was accompanied by a decrease in plasma zinc and an increase in the plasma copper/zinc ratio as well as in the liver zinc. These changes were most remarkable in the zinc-supplemented group.