Discerning a smile - The intricacies of analysis of post-neck dissection asymmetry.

INTRODUCTION: Iatrogenic facial nerve palsy is distressing to the patient and clinician. The deformity is aesthetically displeasing, and can be functionality problematic for oral competence, dental lip trauma and speech. Furthermore such injuries have litigation implications. Marginal mandibular nerve (MMN) palsy causes an obvious asymmetrical smile. MMN is at particular risk during procedures such as rhytidoplasties, mandibular fracture, tumour resection and neck dissections. Cited causes for the high incidence are large anatomical variations, unreliable landmarks, an exposed neural course and tumour grade or nodal involvement dictating requisite nerve sacrifice. An alternative cause for post-operative asymmetry is damage to the cervical branch of the facial nerve or platysmal dysfunction due to its division. The later tends to have a transient course and recovers. Distinction between MMN palsy and palsy of the cervical branch of the facial nerve or platysma division should therefore be made. In 1979 Ellenbogen differentiated between MMN palsy and "Pseudo-paralysis of the mandibular branch of the facial nerve". Despite this, there is paucity in the literature & confusion amongst clinicians in distinguishing between these palsies, and there is little regarding these post-operative sequelae and neck dissections. METHOD: This article reflects on the surgical anatomy of the MMN and cervical nerve in relation to danger zones during lymphadenectomy. The authors review the anatomy of the smile. Finally, case studies are utilised to evaluate the differences between MMN palsy and its pseudo-palsy to allow clinical differentiation. CONCLUSION: Here we present a simple method for clinical differentiation between these two prognostically different injuries, allowing appropriate reassurance, ongoing therapy & management.

Responsive supramolecular polymer metallogel constructed by orthogonal coordination-driven self-assembly and host/guest interactions.

An emerging strategy for the fabrication of advanced supramolecular materials is the use of hierarchical self-assembly techniques wherein multiple orthogonal interactions between molecular precursors can produce new species with attractive properties. Herein, we unify the spontaneous formation of metal-ligand bonds with the host/guest chemistry of crown ethers to deliver a 3D supramolecular polymer network (SPN). Specifically, we have prepared a highly directional dipyridyl donor decorated with a benzo-21-crown-7 moiety that undergoes coordination-driven self-assembly with a complementary organoplatinum acceptor to furnish hexagonal metallacycles. These hexagons subsequently polymerize into a supramolecular network upon the addition of a bisammonium salt due to the formation of [2]pseudorotaxane linkages between the crown ether and ammonium moieties. At high concentrations, the resulting 3D SPN becomes a gel comprising many cross-linked metallohexagons. Notably, thermo- and cation-induced gel-sol transitions are found to be completely reversible, reflecting the dynamic and tunable nature of such supramolecular materials. As such, these results demonstrate the structural complexity that can be obtained when carefully controlling multiple interactions in a hierarchical fashion, in this case coordination and host/guest chemistry, and the interesting dynamic properties associated with the materials thus obtained.

Determination of salivary anticandidal activities in healthy adults and patients with AIDS: a pilot study.

This investigation compared the salivary anticandidal activities of 12 healthy adults with 12 hospitalized patients with AIDS. Stimulated parotid, submandibular-sublingual, and whole salivas were collected during a period of 10 min, immediately acidified, boiled, and then centrifuged to isolate salivary supernatants. Supernatants were then tested for antifungal activity against Candida albicans in blastospore viability inhibition and germ tube formation assays. A unit of blastospore or germ tube antifungal activity was established as that activity yielding 90% or greater inhibition during a defined time period in each salivary assay. Each of the patients with AIDS were found to be defective in one or more of their salivary antifungal activities, and in comparison with healthy adults the differences in antifungal units per milliliter of saliva and total antifungal units were statistically significant for each saliva and each antifungal assay. Defective salivary antifungal activity may contribute to the oral candidiasis seen in patients with AIDS.

Transcutaneous iodine absorption in infants undergoing cardiac operation.

Povidone-iodine is an effective antiseptic, but its topical use has been associated with a number of adverse reactions in burn patients and in neonates as a result of transcutaneous absorption. In particular, high plasma iodine concentrations are known to cause renal failure, metabolic acidosis, and thyroid suppression. Because of the permeable nature of the skin in small infants and the large areas cleaned before cardiac operations, it is possible that significant transcutaneous iodine absorption might occur in this situation. We have studied 17 infants, less than 3 months of age, who were undergoing closed cardiac or thoracic procedures. After povidone-iodine skin preparation in 15 (covering 20% to 30% of body surface area), plasma total iodine concentrations rose fourfold (range, 160% to 1,440%). This increase was significantly different from the preoperative level at 6, 12, 18, and 24 hours. There was no increase in plasma iodine concentration in 2 patients who were not exposed to povidone-iodine or any other iodine-containing compound. We discuss the implications for a topical antisepsis policy in infants.

A correlation between soluble brain nitric oxide synthase and NADPH-diaphorase activity is only seen after exposure of the tissue to fixative.

In histochemical studies using fixed brain tissue, NADPH-diaphorase has been found to be colocalized with soluble nitric oxide synthase. In the present study, using fresh tissues from eight different regions of rat brain, NADPH-diaphorase activity was found mostly in the particulate fraction, whereas most of the nitric oxide synthase activity was located to the cytosolic fraction. Also, the distribution of NADPH-diaphorase activity among brain regions was different from that of nitric oxide synthase. Pretreatment of the fractions with paraformaldehyde virtually abolished the NADPH-diaphorase activity in the particulate fraction, whereas 40-60% of the NADPH-diaphorase activity remained intact in the cytosolic fraction. These results suggest that during fixation most NADPH-diaphorase activity is inactivated and only some of the NADPH-diaphorase activity associated with soluble nitric oxide synthase remains intact.

Lysozyme-protease-inorganic monovalent anion lysis of oral bacterial strains in buffers and stimulated whole saliva.

Similar to Streptococcus mutans, buffer suspensions of Lactobacillus casei, Lactobacillus plantarum, and Fusobacterium nucleatum all undergo cell lysis when treated with the lysozyme-protease-inorganic monovalent anion antibacterial system. For Lactobacillus species treated with lysozyme and proteases at pHs of 4 and 5.3, lysis resulted when a lytic activating concentration of bicarbonate anion followed enzyme treatment. Furthermore, synergistic lysis of these bacteria was noted when lysozyme-protease treatment was followed by bicarbonate anion used in combination with chloride or fluoride anions. Noteworthy, the halides were not active in promoting lysis when used by themselves in the absence of bicarbonate. For F. nucleatum suspended at pH 6.9, lysis was dependent upon the ionic strength of the buffer and resulted when lysozyme-protease treatment of the organism was followed by 100 mmol/L bicarbonate activation. When lysozyme and proteases were omitted from the incubation mixtures and replaced by stimulated whole saliva, pH 5.3, lysis was observed only with L. plantarum and S. mutans, but not with L. casei. The latter could be lysed, however, if suspended in saliva which was diluted several-fold with distilled water. In experiments where lysozyme was selectively depleted from whole saliva by immunoadsorption affinity chromatography, the great majority of the lysis capability of the saliva for L. plantarum was lost, although a significant degree of lysis appeared to be due to salivary factors other than lysozyme. F. nucleatum was also found to lyse in saliva at neutral pH, suggesting that both Gram-positive and Gram-negative oral bacteria may be susceptible to this antibacterial system in vivo.

Factors involved in artificial caries induction by oral streptococci in extracted human teeth.

This study assesses the abilities of S. mutans GS5 and BHT and S. sanguis G9B to produce subsurface lesions on smooth surfaces of extracted human teeth and examines factors which might be responsible for any differences encountered. Teeth were incubated in Brain Heart Infusion broth containing 2% sucrose and a pure culture of the organism to be tested, the media being changed each day for eight days. Surface and media pH's were measured. The mineral content of both the surface enamel and the subsurface lesions was determined by contact microradiography. Significantly deeper and more demineralized lesions were produced by GS5 than by either BHT or G9B. GS5 also produced a lower surface and medium pH and a more dense coating on the teeth. Similar results were obtained with GS5 and G9B when the BHI broth was replaced with FMC synthetic media. It is concluded that the system described is suitable for studying cariogenic potential and will be useful in measuring the anticariogenicity of suspected therapeutic agents.

Release of daunorubicin from polymethylmethacrylate for the improvement of the local growth control of bone metastasis animal experiments.

Bone metastases are a sign of advanced tumor disease. Surgical therapy is only occasionally curative. Therefore, the therapeutic goals are a limited surgical excision, immediate mobilization, effective stabilization and the avoidance of local recurrence. We investigated the effect of the anthracycline daunorubicin (DNR) in conjunction with polymethylmethacrylate (PMMA) in vitro and in animal experiments for regional control of bone metastases. Previous experiments of local chemotherapy in bone metastases using methotrexate (MTX) were done by Langendorff and Hernigou. In our own experiments we improved the release of daunorubicin from polymethylmethacrylate in vitro and in vivo up to 90% by adding mannitol. In in vivo experiments we investigated the combination of DNR and PMMA in athymic nude mice and Wistar rats. Cells from human breast cancer, bronchial carcinoma, nephroma, and soft tissue sarcoma were subcutaneously implanted bilaterally under the dorsal skin of nude mice. After reaching a diameter of 0.5 cm, the tumors were marginally excised, leaving microscopic tumor residuum behind. The tumor cavities were either filled with PMMA or alternatively with DNR-PMMA. The goal was to avoid tumor recurrence in the DNR-PMMA filled resection cavities. The number of recurrences was significantly lower in the DNR-PMMA treated animals, except in the breast cancer group. Additionally we implanted a rat sarcoma intrafemorally into Wistar rats. After 17 days the tumor was marginally excised and the resection cavity was filled with either DNR-PMMA or PMMA alone. The therapeutic goal was to prevent local recurrence. Histological and pharmacological tests concerning toxicity and drug distribution within the body completed the study. We concluded that the addition of daunorubicin to PMMA supplements surgical resection. We were able to reduce the number of, or delay recurrences in our animal models. Systemic side effects could be minimized despite the achievement of high local drug concentrations.

Salivary proteolysis of histidine-rich polypeptides and the antifungal activity of peptide degradation products.

Incubation of purified synthetic histidine-rich polypeptides, HRP-2, -3, -4, -5, -6 (histatins), with diluted human parotid saliva yielded a series of peptide degradation products whose structures could be determined by gas-phase sequencing of cationic polyacrylamide gel electroblots. Sequencing indicated that two and sometimes three peptides were present in the same Coomassie blue-stained band. By comparing different individuals' salivas it was observed that structural variation occurs, perhaps due to differences in the concentrations or specific activities of salivary proteases. Based on the structural data, four proteolytic enzyme activities are proposed. A trypsin-like and chymotrypsin-like enzymatic activity(s) appear to represent the most active salivary protease; however, both an alanine-lysine endopeptidase and a histidine peptidase activity are also present in parotid saliva. In comparison to HRP-4 or HRP-6, degraded products were less active as antifungal agents against Candida albicans both in blastospore and germ-tube assays.

Microbial caries induction in the roots of human teeth in vitro.

Streptococcus mutans GS5, Lactobacillus casei DSM20011 and Actinomyces viscosus T14 produce artificial caries in the roots of extracted teeth. Roots were coated with wax leaving an 8 mm2 window exposed on the buccal surfaces, and then incubated for 8 days in the presence of the test organism, the synthetic medium being changed each day. Samples were then examined by SEM, or microradiographs were obtained from 120 microns sections. The pH at the root surface at the end of the induction averaged 4.43, 5.00 and 5.20, and the lesion depths measured on the microradiographs averaged 121, 83 and 34 microns, for Strep. mutans, L. casei and A. viscosus respectively. This relationship between pH and lesion depth confirms earlier findings. As all of these organisms can produce lesions in tooth structure, elimination of one type would probably not eliminate caries.

Synergism of lysozyme, proteases and inorganic monovalent anions in the bacteriolysis of oral Streptococcus mutans GS5.

Streptococcus mutans GS5 was grown in synthetic medium containing radioactive thymidine to monitor deoxyribonucleic acid release. At neutral pH, cell lysis of hen egg-white lysozyme- or lysozyme-protease-treated cells was dependent upon the nature and concentration of the additive inorganic anions, HCO-3, SCN-, Cl- or F-. At acidic pH, NaHCO3, but not NaSCN, NaCl or NaF, was effective in promoting cell lysis which was due not only to the change in pH but also to the new HCO-3 anion concentration at the new pH. In both pH 4 and 5.2 reaction mixtures, the lysozyme and trypsin acted synergistically with NaHCO3 and the amount of lysis produced was markedly greater than in reaction mixtures containing lysozyme and bicarbonate but no protease. At apparent sub-lytic concentrations of NaHCO3, lysis was achieved by adding an appropriate concentration of one of NaSCN, NaCl or NaF to the lysozyme-protease-damaged cells. Thiocyanate proved to be most effective among the anions requiring lower concentrations to elicit lysis compared to chloride or fluoride for a fixed sub-lytic concentration of bicarbonate. As the NaHCO3 concentration increased, the lysis in the presence of these other anions increased until maximum levels of released deoxyribonucleic acid (DNA) were attained. In addition, the higher the NaHCO3 concentration, the more marked was the change in the degree of cell lysis. At a selected concentration at which NaHCO3 was not effective with any one salt, lysis could be achieved by combining all four inorganic anions at this concentration. The results suggest that the various anions present in oral fluids may together be sufficient to trigger lysis of oral microorganisms.

Quantitation of hepatitis B viral markers in a dental school population.

Ample evidence exists that dentists and dental personnel are vulnerable to hepatitis B disease. Epidemiologic studies, which provide a further understanding of the prevalence, infectious nature, and risks of transmission of the hepatitis B virus, are particularly significant in a dental school environment because of the insidious nature of the virus. Screening should be done for anti-HBs because it is the most reliable marker for hepatitis B infection and is generally believed to confer immunity. However, because no experimental data are available concerning the amount of antibody needed for protection, quantitation of anti-HBs levels in human serum or gingival crevicular fluid would be the first step in ultimately correlating antibody titers to the immune process. In this study, we present quantitative data on the relative antibody titers in a dental school population. Our findings may be of importance for monitoring the effectiveness of vaccination, for improving safety guidelines in dental clinics, and for developing new and rapid oral diagnostic screening methods. Recently, a new method using gingival crevicular fluid has been developed; it permits identification of not only antibody, but also of hepatitis B surface and e antigens (L. Andors, and associates, unpublished data).

General anaesthesia in the dental surgery: a comparison of propofol and methohexitone.

General anaesthesia was assessed in 100 dental patients in general dental practice using either propofol or methohexitone. Mean induction doses were 1.7 mg/kg and 1.5 mg/kg for propofol and methohexitone, respectively. Anaesthesia was maintained with nitrous oxide and oxygen, supplemented in the majority of cases with halothane. Both groups were comparable in relation to satisfactory surgical conditions and recovery. The maximum heart rate following induction of anaesthesia was significantly greater in the group given methohexitone. Despite the satisfactory results obtained in this study the need for full resuscitation facilities will encourage the trend towards most dental general anaesthesia taking place in a hospital environment.

In vitro study on the inhibiting effect of different agents on the growth of Candida albicans on acrylic resin surfaces.

This study evaluated at the in vitro level the antifungal effectiveness of nystatin, chlorhexidine, and a homologous histidine polypeptide on the surface of acrylic resin disks. The agents were used in a way that simulated storage of a denture by a denture wearer. Results indicated that pretreatment with poly-L-histidine was not protective against C albicans adherence and growth regardless of whether disks were stored in water or in the open air for the 8-hour period following yeast contamination. Chlorhexidine was totally effective in preventing C albicans attachment to, and growth on, the acrylic resin, even after a period of 8 days of turbidimetric monitoring. Pretreatment with Nystatin, followed by drying, was protective, yielding results similar to those obtained with chlorhexidine.

Sensitivity of the replica method in the detection of candidal infection among denture wearers with clinically healthy oral mucosa.

To ascertain the role of Candida in denture stomatitis, the practitioner must conduct a mycologic examination of the acrylic resin denture surface, because it acts as a reservoir for continuous reinfection of the palate. Twenty-two patients were examined to compare the sensitivity of the standard technique of swabbing the denture to that of a newly developed cast agar replica technique for detecting Candida albicans. The dentures were swabbed and cast replicas of the tissue-fitting surface of the dentures were made of both study populations. The majority of cultures obtained by swabbing failed to detect the presence of Candida albicans, while all cast agar replicas grew Candida albicans. The replica method for the detection of Candida albicans in edentulous patients seemed to be a more sensitive method than currently available mycologic methods.

A prospective study of 100 gelatin-sealed aortic grafts.

A gelatin-sealed knitted Dacron graft has been developed which has zero porosity at implantation and does not require preclotting. Its patency rate up to 57 months and effectiveness at saving blood loss have been studied. Gelatin-sealed aortic grafts were implanted into 100 consecutive patients--77 men, 23 women. Surgery was performed for aneurysm in 36 patients (including four with rupture), intermittent claudication in 44, rest pain in 17, and gangrene in three, over an 18 month period. The patients were followed up prospectively for 57 months. Perioperative mortality was 1%. Cumulative primary graft patency was 99%. There was no measurable blood loss at implantation. Forty-seven patients required blood transfusion: mean volume transfused was 430 ml. There were no problems related to the sealant.