The prognostic significance of the lymph node ratio in oral cancer differs for anatomical subsites.

The aim of this study was to validate the prognostic significance of the lymph node ratio (LNR) in patients suffering from oral squamous cell carcinoma in regard to different anatomical subsites. A cohort of 430 patients was investigated to determine the rates of primary metastasis and local and regional disease recurrence. Correlation analysis of the LNR with relevant clinical and pathological parameters was performed. Receiver operating characteristic (ROC) curve analysis was conducted to evaluate the prognostic impact for different subsites. Significantly differing rates of primary metastasis and loco-regional disease recurrence were found for cancer of different anatomical subsites of the head and neck. Furthermore, ROC curve analysis suggested that LNR has prognostic relevance in subsets of cancer (tongue, P< 0.001; alveolar process, P= 0.04; maxilla, P= 0.03; buccal mucosa, P= 0.02). The LNR of cancer located in the soft palate (P= 0.6) and floor of the mouth (P= 0.11) showed little or no association with the clinical outcome. There is the need for a more sensitive consideration of the LNR as a factor in the assessment of risk and the treatment decision, as the anatomical subsite plays a crucial role in its impact on the clinical outcome.

Charge/radical site initiation versus coulombic repulsion for cleavage of multiply charged ions. Charge solvation in poly(alkene glycol) ions.

Electrospray ionization of poly(ethylene glycol) (PEG) followed by separation with Fourier-transform mass spectrometry traps (PEG100 + nH)n+ ions. Both collisionally activated dissociation (CAD) and electron capture dissociation (ECD) of these ions (n = 5, 6, 7) produce PEGx fragment ions in which the x values correspond closely to those for an equal distribution of charges in the linear polymer ion, e.g., for n = 7, near x = 1, 17, 34, 50, 67, 83, and 100. However, positions intermediate between these charges should represent the maximum coulombic repulsion, so this is not a specific driving force for fragmentation, which is instead consistent with charge site (CAD) or radical site (ECD) initiation. These conclusions were confirmed by studies of a variety of other poly(alkene glycol) polymers. For these, the ECD spectra of the protonated species are consistent with the predicted charge solvation by the ion's oxygen atoms.

Rare dental abnormalities seen in oculo-facio-cardio-dental (OFCD) syndrome: three new cases and review of nine patients.

Oculo-facio-cardio-dental syndrome is a very rare condition. So far, only nine cases have been documented. We report on three additional female patients representing the same entity. The clinical findings were: congenital cataract, microphthalmia/microcornea, secondary glaucoma, vision impairment, ptosis, long narrow face, high nasal bridge, broad nasal tip with separated cartilages, long philtrum, cleft palate, atrial septal defect, ventricular septal defect, and skeletal anomalies. The following dental abnormalities were found: radiculomegaly, delayed dentition, oligodontia, root dilacerations (extension), and malocclusion. For the first time, fusion of teeth and hyperdontia of permanent upper teeth were seen. In addition, structural and morphological dental changes were noted. These findings expand the clinical spectrum of the syndrome.

The effect of alternatives to formocresol on antigenicity of proteins.

As part of an overall evaluation of possible substitutes for the pulpotomy agent formocresol, this study was initiated to compare the antigenicity of the reaction products of protein with formaldehyde, glutaraldehyde, or dimethylsuberimidate (DMS). Rabbits were injected with rabbit serum albumin (RSA) which had been treated with one of the following solutions: phosphate-buffered saline, 2% glutaraldehyde, 4% formaldehyde, or 2% DMS. The antisera from the rabbits were analyzed for elicited antibodies by the enzyme-linked immunosorbent assay (ELISA) and in a horseradish peroxidase (HRP) assay using a spot technique on nitrocellulose paper. These assays demonstrated that DMS-treated RSA was the most antigenic of the reaction products tested. The least provocative was the glutaraldehyde-treated RSA; the reaction product of formaldehyde was intermediate. Our findings suggest that if non-immunogenicity of a pulpotomy agent is a desirable property, then DMS does not meet the criteria of an alternative pulp fixative. In contrast, the relatively low antigenicity of glutaraldehyde reinforces other favorable findings which support its use clinically.

Chromatographic study of interactions between polyvinylpyrrolidone and drugs.

A chromatographic technique for the study of possible interactions of drugs with soluble or insoluble polymer additives is proposed. Crospovidone was used as a stationary phase. The method allowed the rapid determination of interaction constants in the range of greater than 1 M-1 as relevant for applications in practice. The interaction of 39 drugs and model compounds of diverse chemical structure with povidone and crospovidone was studied. The results closely agreed with data obtained from conventional equilibrium dialysis and sorption studies. The complexation reaction was found to be dominated by hydrogen binding. A close correspondence between the strength of interaction and the nature, number, and position of hydrogen-donating functional groups in the active ingredient was observed. The binding tendency was enhanced when the functional groups were connected with aromatic residues. The carboxyl group was more effective than the hydroxide or amino groups. The binding can be quantified by the binding constants, Kp and Ks, respectively, describing the interaction with polyvinylpyrrolidone via independent binding sites. At pH 1, with the exception of tannic acid, all investigated drugs exhibited Kp and/or Ks values well below an upper limit of 10 M-1. Hence, with additive-drug ratios commonly used in pharmaceutical preparations, the bound amount of drug after oral administration can hardly exceed 3%. In view of this already low degree of potential binding and considering its reversible character and its decreasing tendency with increasing pH during GI passage, the presence of polyvinylpyrrolidone in pharmaceutical preparations is not expected to interfere with GI drug absorption.

Sorption properties of cross-linked insoluble polyvinylpyrrolidone.

The interaction of 32 drugs of diverse chemical structure with cross-linked insoluble polyvinylpyrrolidone (crospovidone) was studied. By using a polymer to drug ratio of 10:1, the sorbed amount for 20 compounds was found to be less than 5%. After a 10-fold decrease of the polymer concentration, the sorbed amount of eight other compounds fell to or below the 5% level. Only tannic acid and hexylresorcinol exhibited a significantly stronger sorption tendency. The interaction appeared to be controlled by phenolic groups in the active ingredient. The binding can be quantified by an interaction constant Ks, whose definition is based on a bulk phase model of interaction via independent binding sites. The exceptionally strong binding of hexylresorcinol, however, apparently was caused by cooperative interacting of the hexyl groups in the bound state. Desorption studies revealed that the binding was fully reversible in all cases. Therefore, the presence of cross-linked polyvinylpyrrolidone as a disintegrant in pharmaceutical preparations is not expected to interfere with GI drug absorption.

Sphere spectrophotometer versus human evaluation of tooth shade.

The purpose of this study was to compare an objective to a subjective method of tooth shade evaluation using the SP78 sphere spectrophotometer and human visual analysis. Twenty extracted fully developed human maxillary teeth had their L* values (lightness) read by the SP78 on day 1 and then again on day 14. Using a blind method, five human evaluators then attempted to match shade tabs from a six-tab experimental Vita shade guide to the same teeth on days 1 and 14. The SP78 L* values read for each tooth were evaluated for a match between those obtained on day 1 and those read on day 14. The results of human evaluation of tooth shade were compared among the evaluators and then between themselves over time. Finally, the ability of human evaluators to match tooth shade was compared with the results obtained with the SP78. The SP78 reproduced L* readings within the standard error of the machine (< or = 1.0) in 16 of 20 (80%) teeth. In contrast, interevaluator agreement expressed as majority agreement (3, 4, or 5 of 5 evaluators agreeing) was only 10 of 20 (50%) teeth on day 1 and 13 of 20 (65%) teeth on day 14. Intraevaluator agreement over the experimental period ranged from 20 to 60%. The results of this study confirm that human evaluation of tooth shade is unreliable and that the SP78 sphere spectrophotometer can provide a more predictable and accurate method of evaluating tooth shade in vitro. This finding opens up a new avenue of investigation for testing the effectiveness of materials and techniques in bleaching discolored teeth.

Effect of smear layer removal on bleaching of human teeth in vitro.

The purpose of this study was to evaluate objectively in vitro the effectiveness of bleaching artificially discolored teeth with or without the smear layer present using sodium perborate mixed with sterile water or 35% hydrogen peroxide (H2O2). Seventy fully developed maxillary anterior teeth were artificially stained with human hemoglobin and separated into one control and four experimental groups. After the smear layer was removed on half the experimental teeth and left intact on the other half, all of the teeth were bleached intracoronally with sodium perborate and 35% H2O2 or sodium perborate plus water. The bleaching agents were applied twice over a 6-day period. The changes in tooth shade were objectively analyzed using a SP78 sphere spectrophotometer at 1, 30, and 60 days postbleaching. The presence or absence of the smear layer did not significantly influence the outcome of bleaching (p > 0.05). The teeth bleached with sodium perborate and 35% H2O2 were significantly lighter than the teeth bleached with sodium perborate and sterile water (p < 0.0001) at each experimental period. Based on the findings of this study, it is not advantageous to remove the smear layer before intracoronal bleaching.

A novel method for embedding neonatal murine calvaria in methyl methacrylate suitable for visualizing mineralization, cellular and structural detail.

The study of undecalcified bone by histological methods is essential in the field of bone research. Culturing skeletal tissues such as neonatal murine calvaria provides a reliable bridge between assessment of bone formation in vitro and anabolic activity in vivo and contains most of the essential elements of bone for studying bone formation. Neonatal calvarial assay, supported by histological methods, is used to study the anabolic effects of a wide variety of factors and compounds on bone tissue. To optimize visualization and histomorphometric measurements using neonatal calvaria, we developed a method that provides high quality tissue sections suitable for routine and histochemical staining. Undecalcified neonatal mouse calvaria were processed and embedded using a low temperature methyl methacrylate procedure. Various staining methods were performed on deplastisized and floated sections to examine mineralization and to identify cells. The Von Kossa stain counterstained with a modified H & E yielded precise images of unmineralized bone including mineralization sites, and distinct osteoblasts and osteoclasts. Toluidine blue, Ladewig's trichrome, tartrate-resistant acid phosphatase, Goldner, H & E and Villanueva stains also were tested on the undecalcified neonatal calvaria sections.

Phenotype and counseling in lacrimo-auriculo-dento-digital (LADD) syndrome.

A girl who presents most features of LADD syndrome together with growth retardation is described. Significant digital abnormalities are lacking. Comprehensive examination of the family revealed slight features of LADD syndrome in the father of the proband. A risk of 50% was estimated for sibs.

Assessment of the systemic distribution and toxicity of glutaraldehyde as a pulpotomy agent.

The systemic distribution of glutaraldehyde (GA) from a pulpotomized tooth of a rat was estimated to be 40 nanomoles or 25% of the applied dose. Metabolic studies disclosed that GA was eliminated in urine and expired gases; 90% was cleared from body tissues in 3 days. To evaluate the toxicity of GA, doses 500x greater than that systemically distributed from a pulpotomy site were infused into the jugular veins of rats. Twenty-four hours postinfusion the rats were evaluated in vivo for physiologic changes or sacrificed for biochemical and histologic evaluation of harvested tissues. Only one of the assays, a physiologic parameter, was altered by the 500x dose. Considering the relatively large dose administered and the limited effects, we conclude that GA would not be toxic when used as a pulpotomy agent.

Oculo-facio-cardio-dental (OFCD) syndrome.

The association of facial dysmorphy, congenital cataracts, microphthalmia, heart disease, and dental radiculomegaly is very rare. We describe a girl with atrial septal defect, unilateral congenital cataract, unilateral microphthalmia, radiculomegaly of incisor and canine teeth with open apices and other dental crown anomalies. This combination of symptoms clearly represents a distinct syndrome and has recently been described as oculo-facio-cardio-dental (OFCD) syndrome.

Assessment of the systemic distribution and toxicity of formaldehyde following pulpotomy treatment: Part two.

The active constituents of formocresol, formaldehyde and cresol, are known toxic agents. The authors administered increments of formaldehyde until systemic morbidity was demonstrated so that tissue damage could be equated with the number of concurrent pulpotomies required to achieve a toxic body load.

Subcellular localization of glutaraldehyde.

Glutaraldehyde (GA) has been proposed as an alternative to formocresol for pulpotomies in primary teeth and as an irrigant in root canal therapy. These studies were undertaken to determine if GA can associate with the nucleus of living cells, thereby posing a mutagenic threat. Rats were infused IV with 14C-GA and killed 5 min and 1 h later. The cystolic, membrane, and nuclear fractions of harvested liver cells were separated and analyzed for radioactivity. We determined that significant radioactivity was located in the cytosol and membrane fractions, but not in the nuclear fraction. In an in vitro experiment, liver slices were incubated with 14C-GA in sealed vials in which 14C-CO2 was captured. After 1 h the nucleic acids of the liver slices were isolated and counted. In vitro the liver cells incorporated and metabolized GA to CO2 but no significant label could be detected in the isolated nucleic acids. We concluded from these experiments that GA which was incorporated into liver cells did not reach the nucleus to a significant extent, and that its potential for mutagenicity in the context of pulp treatment was nil.

The role of surface charge on the accelerating action of heparin on the antithrombin III-inhibited activity of alpha-thrombin.

We have compared surface charge and the surface charge density on the polyanions heparin and potassium polyvinyl sulfate (KPVS), as well as on hydrolyzed heparin and KPVS, with their accelerating effect on the inhibitory action of antithrombin III on thrombin. Polyelectrolyte titration of thrombin with KPVS or heparin at pH 7.4 clearly indicates an electrostatic interaction. In contrast, at the same pH no electrostatic interaction is observed between polyanions and antithrombin III. KPVS accelerates the inhibitory action of antithrombin III to the same extent as heparin on the basis of charge equivalence. Heparin and KPVS with a mean distance between two charged centers of less than 0.75 and 0.95 nm, respectively, accelerate strongly whereas hydrolysates with lower charge densities are far less active. The following observations are indicated. Intramolecular neutralization of oppositely charged residues occurs within thrombin, antithrombin III, and partially hydrolyzed heparin. Heparin acts on the antithrombin III-thrombin reaction through cooperative electrostatic binding to thrombin and nonelectrostatic interaction with antithrombin III. This indicates a quasi-catalytic action of the polyelectrolyte. Hydrolysis of only a few N-sulfate residues within the heparin molecule decreases the linear surface charge density to such an extent that the accelerating action is drastically reduced. The loss of accelerating capacity agrees with the sudden loss of counterion condensation due to the decrease of the linear surface charge density beyond limits postulated by Manning in a theory of polyelectrolytes.

The surface charge of apolipoproteins, phospholipid liposomes, and human very low density lipoproteins.

The surface charge of isolated apolipoprotein A-I, apo-A-II, apo-C-II, and apo-C-III2 as well as of liposomes from synthetic highly purified phospholipids and isolated very low density lipoprotein (VLDL) particles from different donors (n = 35) was determined by polyelectrolyte titration. The particle size of apolipoproteins was evaluated from their molecular weight and specific volume, while that of VLDL particles was determined by photon correlation spectroscopy. The surface charge density of apolipoproteins and of VLDL at pH 7 was calculated from the number of surface charges of the particle and the surface area. The experimental net charge versus pH curves for apo-A-I and apo-A-II are very similar to the theoretical data. The differences between experimental and calculated results for apo-C-II and apo-C-III2 are believed to result from "polyelectrolyte" effects of neighboring charged centers within the protein molecule causing a decrease of dissociation of carboxylic residues. Neutral phospholipid liposomes do not exhibit anionic or cationic properties between pH 3 and 9. Liposomes from anionic phospholipids behave similar to polymeric carboxylic acids, i.e. their degree of dissociation increases with pH. The number of surface charges of VLDL particles increases with the particle size, while their surface charge density is about 1.10 +/- 0.36 charges/nm2 of the surface area.

Ellis-van Creveld syndrome: examination at 15 weeks' gestation.

In 1940, Ellis and van Creveld defined a syndrome they referred to as chondro-ectodermal dysplasia. This autosomal recessive condition, now usually referred to as Ellis-van Creveld syndrome (EVC), comprises bilateral postaxial polydactyly, a chondrodysplasia, characterized by shortness of limbs, and ectodermal dysplasia. Congenital heart defects are also common. There are many reports in medical literature describing affected newborns and even, older children. Here, we report the clinical, radiological and histological findings in a 15-week-old affected fetus. The diagnosis of Ellis-van Creveld syndrome in this fetus is based on a positive family history (an affected sib) and shortness of long bones as well as hexadactyly diagnosed by prenatal ultrasonography. On post-mortem examination, bilateral postaxial hexadactyly and symmetrical shortness of the long bones was noted. Histologically, there was too short a zone of cartilagineous columns in the metaphyses, a reduced number of chondrocytes and an irregularly structured spongiosa within the ossification zone. In addition, the fetus was found to have an atrio-ventricular canal. This heart defect is presumably rare in this syndrome. Other characteristic features such as small and dysplastic nails, sparse hair and abnormalities of the teeth were, of course, not yet present in this early developmental stage. In addition to EVC, the fetus had a 47,XXY chromosome constitution.