bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of gene conversion on polymorphic patterns at major histocompatibility complex loci
Authors: Ohta Tomoko
Published: April 2006

Summary: The pattern of polymorphisms at MHC loci was studied by computer simulations and by DNA sequence analyses, with special reference to synonymous and non‐synonymous divergence among alleles. A model of overdominance plus short‐term selection was simulated for a gene family with allelic and non‐allelic gene conversion. It was found that the ratio of non‐synonymous‐to‐synonymous divergence among alleles decreases as the non‐allelic conversion becomes more frequent. On the other hand, the ratio of synonymous divergence at the antigen recognition site to that at non‐coding region increases by non‐allelic: conversion. By comparing such a pattern with the observed values of mammalian genes, it is suggested that non‐allelic conversion is less frequent in human genes than in genes of other mammals. A quantitative analysis on the patchwork pattern was attempted by using identity excess among nucleotide sites of a gene. Comparison of simulation results with DNA data analysis shows that the rate of allelic conversion is high.
Phylogenetic history of hominoid DRB loci and alleles inferred from intron sequences
Authors: Bergström Tomas F. , Erlandsron Rikard , Engkvist Hans , Josefsson Agnetha , Erlich Henry A. , Gyllensten Ulf
Published: April 2006

Summary: The evolutionary relationships among the MHC class II DRB4, DRB5 and DRB6 loci as well as the allelic lineages and alleles of the DRB1 locus were studied based on intron 1 and Intron 2 sequences from humans, chimpanzee (Pan troglodytes). bonobo (Pan paniscus) and gorilla (Gorilla gorilla). The phylogenetic trees for these sequences indicate that most of the DRB 1 allelic lineages predate the separation of the hominoid species studied, consistent with previous analysis of the coding sequences of these lineages. However, the intron sequence variation among alleles within DRB1 allelic lineages is very limited, consistent with the notion that the majority of the contemporary alleles have been generated within the last 250,000 years. The clustering of the DRB1 allelic lineages *08 and *12 with *03 supports a common ancestry for the DR8 and DR52 haplotypes. Similarly, the clustering of DRB1 allelic lineages *15 and *01 with the DRB3 locus is consistent with a common ancestry for the DR1 and DR51 haplotypes. Two cases of recombination around the second exon were observed: 1) the HLA‐DRB6 locus appears to have been generated through a recombination between a DRB5 allele and an ancestral DRB6 allele, and 2) the gorilla sequence Gogo‐DRB1*03 appears to have been generated through a recombination between the DRB3 locus and an allele from the DRB1*03 allelic lineage. The nucleotide substitution rate of DRB introns was estimated to 0.85–1.63 × 10‐9 per site per year, based on comparisons between the most closely related sequences from different hominoid species. This estimate is similar to the substitution rate for other intronic regions of the primate genome.
Molecular clock and recombination in primate Mhc genes
Authors: Satta Yoko , Kupfermann Heike , Li Yi‐Ju , Takahata Naoyuki
Published: April 2006

Summary: To set an accurate chronological framework to the evolution of primate class I and II genes in the major histocompatibility complex (Mhc), the rate of silent nucleotide substitutions in exons and introns is examined for various cDNA and genom sequences currently available. The rate is sensitive to the GC content and correlates negatively with increased GC biases at the third codon positions of Mhc genes. The intergenic recombination rate in the HLA region is estimated from the synonymous nucleotide differences at 37 linked loci. Any HLA subregion is recombined more or less at the ordinary rate of 1 cM per 1 Mb, although the rate may be reduced in some subregions. This information is used to discuss HLA haplotypes when they are applied to studies of human demography The unusual polymorphism in the α‐helix of HLA‐DRB1 is also revisited in relation to intragenic recombination, but the molecular mechanism and the evolutionary cause both remain enigmatic.
Possibility of a viral etiology in recurrent aphthous ulcers and Behçet's syndrome
Authors: Hooks John J.
Published: April 2006

Abstract The clinical signs, laboratory data, and histological features of recurrent aphthous ulcers (RAU) and Behçet's syndrome suggest a viral etiology. In fact, there are reports of adenovirus isolations in herpetiform oral ulcers and on the isolation of a filterable agent in sporadic cases of Behçet's syndrome. However, isolation studies on the major and minor aphthous ulcers and more recent studies on Behçet's syndrome have been negative. A review of the literature on the role of viruses and autoimmunity in RAU and Behçet's syndrome is presented.

Biopsy specimens of ulcerative lesions were grown in vitro for up to 300 days. Those cultures, along with leukocytes and body fluids, were examined by a variety of techniques for the presence of virus or viral antigens. Although a persistent or latent virus was not detected, these negative studies cannot exclude a viral etiology. In fact, the hypothesis of an infectious and viral etiology is still reasonable.
Ulcerative diseases of animals with an infectious etiology
Authors: Mebus Charles A.
Published: April 2006

Abstract The oral lesions of five viral diseases of cattle are compared. Two of the diseases, foot‐and‐mouth disease and vesicular stomatitis, cause vesicles, and rinderpest, bovine virus diarrhea and malignant catarrhal fever produce sharply demarcated erosive lesions. Gross lesions of different diseases appear similar: however, histologically, there are subtle differences in the development of the lesions.
Double‐blind trial of tetracycline in recurrent aphthous ulceration
Authors: Graykowski Edward A. , Kingman Albert
Published: April 2006

Abstract A double‐blind trial of a tetracycline suspension was carried out in 25 patients with recurrent aphthous oral ulcerations. A combined topical‐systemic treatment procedure was used. Both the placebo and tetracycline groups experienced reductions in ulcer incidence during the treatment period, whereas only the tetracycline group showed significant reductions in ulcer duration, size, and pain. Tetracycline treatment apparently alters the severity of the ulcer, but does not appear to affect those factors responsible for recurrences. The side effects recorded in patients taking tetracycline were comparable to those in patients on placebo.
Double‐blind study of levamisole therapy in recurrent aphthous stomatitis
Authors: Olson James A. , Silverman Sol
Published: April 2006

AbstractForty‐eight patients with diagnosed recurrent aphthous stomatitis participated in a randomized double‐blind study of levamisole therapy. Each patient's response to treatment was determined by the following criteria: (1) days between attacks, (2) duration of lesions, (3) patient's self‐evaluation of pain, (4) investigator's clinical evaluation of patient's subjective treatment response. Statistical analysis of the levamisole and placebo groups for criteria 1 and 2 above revealed no significant difference. In contrast to the above findings, analysis of the investigator's recordings of patient's subjective treatment response showed that 26 % of the levamisole patients experienced marked or moderate improvement. None of the placebo patients were recorded as having experienced the same degree of benefit. Fourteen of 15 patients who complained of side effects were taking levamisole. The most common side effects were dysgeusia and hyperosmia.
Double‐blind study of levamisole in aphthous stomatitis
Authors: Kaplan B. , Cardarelli C. , Pinnell S. R.
Published: April 2006

Abstract Sixty‐five patients with recurrent aphthous stomatitis participated in a double‐blind study to evaluate levamisole. Nineteen of 34 patients improved on levamisole and only five of 31 patients improved on placebo (P>0.004, chi‐square with two degrees of freedom). After breaking the code and switching placebo patients to levamisole and non‐responders to an alternate dosage schedule, 46 of 60 patients noted clinical improvement.

This is publication number 33 of the Dermatological Research Laboratories of Duke University Medical Center.
Evaluation of the therapeutic effect of levamisole in treatment of recurrent aphthous stomatitis
Authors: Gier Ronald E. , George Barbara , Wilson Tim , Rueger Arvon , Hart Jerry K. , Quaison Felix , Hardman Patrick K.
Published: April 2006

Abstract Recurrent aphthous stomatitis is a chronic, painful, ulcerative disease of the oral mucosa, which affects up to 60 % of the population. No effective cure or treatment is available. Levamisole is a drug reported to restore deficient immunologic states to normal and to reduce the incidence and severity of recurrent aphthous stomatitis. Sixty‐five patients with attacks of recurrent aphthous stomatitis which recurred at least every 2 months were entered in a double‐blind evaluation of the therapeutic effect of levamisole on their disease. Fifty‐seven completed the double‐blind study by taking the supplied medication for six recurrences of their aphthous lesions. Forty‐two of those completing the double‐blind study entered an open study to evaluate the long‐term effects of levamisole on recurrent aphthous stomatitis.

Each patient took the supplied medication at the onset of each recurrence of their aphthous lesions. They were examined and evaluated at each recurrence of their lesions. The levamisole was supplied in 50‐mg tablets and taken by mouth at a dosage of 150 mg daily for 3 days. Pregnant patients were excluded from the study.

A reduction in the duration of the aphthous lesions from 10.7 days to 6.07 days was obtained in the double‐blind study by the group taking levamisole. The placebo group had a reduction from 10 to 8.62 days. The reduction in the duration of the lesions continued in both groups in the open study. No reduction was noted in the days between recurrences of the lesions in the double‐blind or open study. No changes were noted in the RBC, WRC, differential white count, hemoglobin or hematocrit. Nineteen patients (33%) experienced side effects to levamisole. The most frequent reported were nausea, dysgeusia and hyperosmia.
Randomized, double‐blind study of levamisole in recurrent aphthous stomatitis
Authors: Drinnan Alan J. , Fischman Stuart L.
Published: April 2006

Abstract A randomized double‐blind study was designed to evaluate the safety and efficacy of levamisole in the treatment of recurrent aphthous stomatitis (RAS). Thirty patients, aged 9–65 years, were selected, based on a documented history of three or more episodes of RAS. Patients were instructed to take 150 mg of levamisole (or placebo) daily for 3 days at the onset of the first prodromal symptoms of an ulcer. The regimen was to be repeated for each new episode, but not more than once per week. At each episode patients were examined and evaluated as to number and duration of ulcers, interval between episodes, pain associated with ulcers, and side effects. Data on 24 patients were suitable for analysis. Of those patients receiving levamisole, six showed slight improvement and five were unchanged. Of those patients receiving the placebo, one showed a marked improvement, four slight improvement, six were unchanged, and two deteriorated. There was neither a clinical nor a statistically significant difference between the groups. It is concluded that levamisole, in this study protocol, had no effect on the incidence or severity of aphthous ulcers.
Nutritional deficiencies in recurrent aphthae
Authors: Wray D. , Ferguson M. M. , Hutcheon A. W. , Dagg J. H.
Published: April 2006

Abstract A series of 330 patients with recurrent aphthae was screened for deficiencies of iron, folate and vitamin B12, In 47 patients (14.2 %) such deficiencies were found; 23 were deficient in iron, seven in folic acid, six in vitamin B12 and in addition 11 patients had combined deficiencies.

Clinical examination of the aphthae was not helpful in identifying individual patients with a nutritional deficiency although patients with an associated glossitis or angular cheilitis were more likely to suffer from such deficiencies.

Screening of the patients by examination of their peripheral blood alone (estimation of haemoglobin and absolute values, and blood film examination) detected only a proportion of those with deficiencies of iron or folic acid, although in this series such screening was able to identify the small number of cases with vitamin B12 deficiency.

The 39 patients with a proven nutritional deficiency who were available for follow‐up showed a favourable response to corrective therapy; 23 showed a complete remission of ulcers, 11 were improved and five were not helped.

The significance of these findings is discussed. It is suggested that the results indicate the need for full haematological screening of all patients with recurrent aphthae.
Immunological aspects of recurrent oral ulceration and Behçet's syndrome
Authors: Lehner T.
Published: April 2006

AbstractImmunological factors play an important part in recurrent oral ulceration (ROU) and Behçet's syndrome (BS) but these cannot be distinguished by means of antibodies and cell‐mediated immune responses to oral mucosal antigens. However, HLA markers seem to differentiate ROU from BS. Immune complexes have now been found in about 55 % of patients with BS and fewer patients with ROU, so that the transition from the focal ROU to the multifocal BS might be mediated by immune complexes. Immunopathological studies have shown that a vasculitis is the essential lesion in BS and this might be secondary to immune complexes inducing complement activation and damage. It is not clear at present whether the increased levels of C9 and C‐reactive protein are a manifestation of acute phase reactants. C9 could be involved in complement dependent lysis and C‐reactive protein in modulating the cell‐mediated immune responses by its effect on T lymphocytes. It seems that at least two types of damaging immune mechanisms have been identified; cell‐mediated and immune complex induced reactions and these might account for the association between ROU and BS.
Topographical distribution of sulfated glycosaminoglycans in the surface layers of the human temporomandibular joint
Authors: Kopp Soigvard
Published: April 2006

The right temporomandibular joint (TMJ) was removed at autopsy from 18 individuals and the articular surfaces were scored for macroscopic lesions. Soft tissue specimens were cut out of the medial, lateral and posterior parts of the temporal and condylar components and frozen. The sections were stained with toluidine blue (1‐N HC1 solution) and with alcian blue (CEC method) for sulfated glycosaminoglycans. The sections were examined for inter‐ and pericellular metachromasia and alcian blue staining. Macroscopic surface lesions were found in 14 of the joints. The highest score of inter‐and pericellular metachromasia was found in the anterior parts of the joints and a negative correlation was found between the score of surface lesions and that of intercellular metachromasia. Pericellular metachromasia was found mainly in the mineralized cartilage and cartilage layers of the articular surface. Although the CEC values of pericellular staining commonly reached a level indicating the presence of keratan sulfate, the majority of the CEC values found corresponded to those of chondroitin‐dermatan sulfate. It was concluded that sulfated GAG are localized mainly to the anterior part of the TMJ and that macroscopic TMJ surface lesions are associated with a reduction of sulfated glycosaminoglycans.
Ultrastructural study of adenomatoid odontogenic tumor
Authors: Hatakeyama Setsuko , Suzuki Atsumi
Published: April 2006

Two cases of adenomatoid odontogenic tumor were examined by light and electron microscopy. Morphologically the tumors could be divided into four layers. The ultrastructure of the tumor cells of each layer was revealed to be similar respectively to that of four layers seen in the enamel organ of a normal tooth germ. Duct‐like structures and eosinophilic small areas were frequently present in compactly proliferating cell layers. Short columnar cells forming duct‐like structures and eosinophilic small areas appeared similar ultrastructurally to ameloblasts during predentin formation. Therefore it seems reasonable to assume that this tumor originates from the enamel organ.

The contents in the lumen of each eosinophilic small area varied, and seemed to be secreted into the stroma by circumscribing epithelial tumor cells. A fine filamentous layer was present in both of the duct‐like structures and some of the eosinophilic small areas, and the former was different from the latter with respect to the alcian blue (pH 2.5) and toluidine blue (pH 4.4) staining reactions.
Lipopigment in odontogenic cysts
Authors: Buchner Amos , David Raffaele
Published: April 2006

A study of 105 odontogenic cysts revealed the presence of pigmented cells in the cyst wall in 38% of the cases. The frequency of pigmented cells was higher in the inflammatory odontogenic cysts than in the developmental cysts. Although isolated pigmented cells were seen within the epithelial lining and cyst cavity, the larger collections were closely associated with cholesterol crystals and hemosiderin deposits; they contained light brown cytoplasmic pigment which manifested sudanophilia, acid‐fastness, silver reduction capacity, PAS positivity and yellow autofluorescence in ultraviolet light. The morphology, histochemical reactions and autofluorescence suggest that the pigmented cells are macrophages containing ceroids.

It has been suggested that the hemosiderin which is found in the cyst wall serves as an oxidation catalyst for the locally liberated lipids, the end result of which is the formation of the ceroid pigment.
The relationship between the dose of dentogingival plaque and the in vitro lymphoproliferative response in subjects with periodontal disease
Authors: Church Hillary , Dolby A. E.
Published: April 2006

The in vitro lymphoblastic response to autologous dentogingival plaque (DGP) extract at nine concentrations was measured in 28 individuals (Periodontal Index (Russell 1956] 0.8–7.4). Significantly elevated responses were obtained in 25 of the patients but the levels of the peak responses were unrelated to the severity of the disease. There was a significant (n=28, r=−.734) negative linear relationship between the PI of the individuals studied and the logarithmic concentration of DGP producing the peak lymphoblastic response. Lower concentrations of DGP extract would appear to be required to achieve peak responses in patients with severe periodontal disease.
A morphologic study of the recovery of the rat submandibular gland after retrograde infusion
Authors: Qwarnstrom E. E. , Hand A. R.
Published: April 2006

Lipid‐soluble radiographic contrast medium was infused retrogradely through the main excretory duct of the rat submandibular gland until ductal and slight parenchymal filling or heavy parenchymal filling was achieved, as determined by the developing intraglandular pressure. The glandular tissue was fixed by vascular perfusion at different times following infusion, and examined by light and electron microscopy. Dilation of the intralobular ducts and scalloping of the luminal border were pronounced after both degrees of filling. Widening of the acinar lumina and intercellular canaliculi occurred early. Masses of fused secretory granules were commonly seen in the cytoplasm of the acinar cells and formation of vacuoles occurred frequently. In some acinar cells, densely packed granules filled the major part of the cytoplasm. Large lysosomes and autophagic vacuoles, frequently present in the various parenchymal cells, often contained apparent contrast medium. In addition, widening of the intercellular space between parenchymal cells was seen, particularly in the acini and intercalated ducts. An inflammatory cell‐infiltrate, primarily comprised of polymorphonuclear leukocytes, was particularly prominent at 20 h and 30 h after infusion. The changes were generally more pronounced and persisted for a longer time in glands subject to heavy parenchymal filling. Large cyst‐like spaces surrounded by inflammatory cells were seen in the lobules and in the interlobular connective tissue of these glands. At later times, areas containing apparent contrast medium surrounded by macrophages, were frequently observed in the connective‐tissue stroma. Atrophy of the parenchymal cells was seen later, after heavy parenchymal filling, and a proliferation of the connective tissue had occurred. The changes were most probably caused by the elevated intraglandular pressure induced during infusion, and the subsequent; cell damage and inflammatory reaction. A foreign body reaction, induced by the retained lipid‐soluble contrast medium, was probably partly responsible for the morphological alterations observed, following infusion.
Loss of the Y chromosome in a cultured human salivary‐gland adenocarcinoma
Authors: Stenman G. , Mark J.
Published: April 2006

Using in vitro methods, the G‐banding pattern in a highly differentiated adenocarcinoma of the parotid gland is described. Results from two consecutive preparations of the carcinoma indicated that it had originated with a normal diploid stemline and, subsequently, during progression had developed an aneuploid stemline deviating from the normal only by loss of the Y chromosome. From this hypodiploid stemline some clones and variant cells had been generated, all of them characterized by numerical deviations, particularly various trisomies. Important cytogenetic similarities were found between the present adenocarcinoma and other types of salivary gland neoplasms, in particular pleomorphic adenomas.
Immunocompetent cells in labial salivary glands in secondary Sjögren's syndrome associated with SLE
Authors: Kilpi A. , Konttinen Y. T. , Malmström M. , Bergroth V. , Reitamo S. , Helve T.
Published: April 2006

T and B lymphocyte (sub)populations were identified by monoclonal hybridoma antibodies (the avidin‐biotin‐peroxidase complex method), in the periductal lymphocyte‐rich infiltrates in the labial salivary glands of 8 patients with secondary Sjögren's syndrome (2°SS) associated with systemic lupus erythematosus (SLE). 59 ± 7% and 17 ± 3% of inflammatory round cells in situ were T3‐positive and surface(SIg)‐ or cytoplasmic(CIg) immunoglobulin‐positive, respectively. This suggests a local T lymphocyte dominance in salivary glands in 2°SS associated with SLE. The local ratio of cells expressing T inducer/helper: T suppressor/cytotoxic phenotype was 3.5 ± 0.8 (range 0.9–7.6) indicating large variations between individual patients. 46 ± 9% of all inflammatory cells in situ were endogenous peroxidase‐negative, Ia‐positive cells, suggesting an active role for the locally accumulated T lymphocytes.
Effects of adriamycin on calcium concentration and morphology of mouse salivary glands
Authors: Jirakulsomchok D. , Yu J.‐H. , Sheetz J. H. , Schneyer C. A.
Published: April 2006

A large single dose (15 mg/kg body wt, ip) of the antitumor agent adriamycin (ADR) caused a marked increase in calcium concentration of submaxillary gland of female mice, and a smaller increase in the parotid gland within 2 days of injection. A small dose (2.5 mg/kg body wt) had no effect. The histological appearance of the glands was also changed and included an increase in size of granules and acinar cells of the submaxillary glands and a decrease in size of acinar cells of the parotid. At the EM level, there was evidence of mitochondrial alteration in the parotid but not in the submaxillary glands. Rough endoplasmic reticulum (RER) was markedly disorganized in the parotid, and abnormal whorls of RER were evident. Submaxillary glands showed no change in RER. Water content of either gland was unchanged from that of controls. Heart ventricles, unexpectedly, showed no change in calcium concentration from that of control tissues, at 3 h, 1, 2 or 4 days after ADR administration. The [Ca] changes induced by ADR in the submaxillary glands are not mediated via β‐adrenoceptor activation since propanolol did not alter the ADR‐induced changes. The marked difference in response of the glands (and heart) to ADR, suggests that the mechanisms invlolved in calcium homeostasis in these organs are very different.
An electron‐microscopic and cytochemical study of follicular ameloblastoma
Authors: Cutler L. S. , Innes D. J.
Published: April 2006

The ultrastructural and enzyme cytochemical features of two follicular ameloblastomas were investigated. The peripherial cells of the follicular areas in both lesions had several types of tall columnar cells which were highly polarized and showed varying degrees of cellular differentiation. These polarized cells had their nuclei situated away from the basal lamina, and often contained dilated strands of endoplasmic reticulum in the subnuclear cytoplasm. Some of these cells also contained dense‐cored secretory granules, condensing granules and coated vesicles in the cytoplasm adjacent to the basal plasma membrane. These cells bore a striking resemblance to pre‐ameloblasts and early secretory ameloblasts. Alkaline phosphatase and ATPase cytochemistry supported these morphologic observations. Interestingly, the central cells of the follicular areas were consistently negative for alkaline phosphatase activity as were the peripheral cells, while both cell types had ATPase activity demonstrable at their cell surface.
Surface markers of human gingival fibroblasts in vitro. Characterization and modulation by enzymes and bacterial products
Authors: Barber S. , Powell R. N. , Seymour G. J.
Published: April 2006

Surface markers of human gingival fibroblasts in vitro were investigated using monoclonal and helerologous unlisera against a range of cell surface antigens, together with resetting techniques to characterize surface receptors for IgG and C., WI‐38 fibroblasts and human peripheral blood monocytes were used as control cells. Human gingival fibroblasts exhibited complement receptors and (β2‐micro‐globulin, as did W1–3S cells. Ten per cent of the human gingival fibroblasts were positive for HLA‐DR antigens and additionally exhibited a granulocyte antigen not apparent on WI‐3K cells. Monolayers of the gingival fibroblasts were further exposed for short periods to varying concentrations of enzymes (trypsin, collagenase and neuraminidase), bacterial extracts (lipopolysaccharide and lipoteichoic acid) and crude supra‐ and subgingival plaque sonicates. Surface‐marker analysis was then carried out. The most noticeable effects were obtained with Vibrio cholerae neuraminidase which enhanced C3, receptor and surface antigen expression, and supragingival plaque sonicate which depressed the expression of HLA‐DR and granulocytc antigens while not affecting β2microglobulin expression. Trypsin reduced antigen expression to a degree, but its effects were mainly on cell adherence.
A qualitative ultrastructural study of the intercellular spaces between epithelial cells treated in vivo with DMBA
Authors: White F. H. , Gohari K.
Published: April 2006

One of the features of epithelial dysplasia at the histological level is known as “loss of cellular adherence” in which adjacent epithelial cells appear more widely separated from each other than in normal tissues. In this study we examine the effects of the carcinogen DMBA on the epithelium of the hamster cheek‐pouch with particular emphasis on the dimensions of the intercellular spaces. DMBA‐induced lesions were processed for electron microscopy and assigned to hyperplasia, dysplasia and carcinoma groups, using defined criteria on toluidine blue‐stained 1 urn Araldite sections. Untreated pouches were used as a control. At the light‐microscopical level, intercellular spaces in hyperplastic epithelium appeared similar to those present in untreated tissue but increased progressively in dysplastic and car‐cinomatous lesions. Spaces were generally wider between basal and spinous cells than between granular cells, although wide variations were observed between tissue blocks demonstrating similar histological features and also within adjacent areas of the same block. At the ultrastructural level, untreated and hyperplastic tissue showed only occasional focal separations of adjacent plasma membranes; these spaces were more frequent between cells of lower strata. In sections from dysplasia and carcinomas, spaces were always extensive and were occupied by numerous villous or foliate membrane‐bound cytoplasmic extensions. These were often attached to each other by desmosomcs of apparently normal morphology but of a lower frequency than in untreated epithelium. The increased epithelial separation as indicated by the increased intercellular spaces during chemical cardnogenesis may be a result of any or all of the following factors: desmosomal disruption or their failure to develop; the production of cell‐surface molecules which are less adhesive; inflammatory oedema and direct alterations on intercellular junctions and cell‐surface components by infiltrating inflammatory cells.
Alterations in the volume of the intercellular space between epithelial cells of the hamster cheek‐pouch: quantitative studies of normal and carcinogen‐treated tissues
Authors: White F. H. , Gohari K.
Published: April 2006

The present report investigated the extent of the epithelial dysplastic feature known as “loss of cellular adherence” at the ultrastructural level by quantifying the volume of the intercellular space during hamster cheek‐pouch carcinogenesis. Following topical application of DMI3A to cheek‐pouches, lesions were classified as hyper‐plasia, dysplasia and carcinoma, with untreated pouches serving as a control. Stereological point counting procedures were used to determine the volume density of intercellular space in defined basal, spinous and granular layers for each group. In general, progressive increases in volume density were detected within each stratum during carcinogenesis. These results indicate that increasing separation of epithelial cells occurs during carcinogenesis, although it is not yet known whether this results from loss of cohesion between specialised (i.e., desmosomal) or non‐specialised membrane areas. In addition, a simple indicator of pathological alteration, the Pathological Alteration Ratio (PAR), is described and was used to evaluate existing published data for intercellular spaces in various oral mucosal conditions. Values of the PAR were found to be substantially higher in carcinogen‐treated epithelia than in reports describing changes in wound healing, lichen planus and leukoplakia simplex. These objective techniques are of value for investigating the pathogenesis of diseased epithelium and may find applications in the diagnosis of oral premalignant lesions.
Surface changes in rat gastric mucosa induced by sodium fluoride: a scanning electron microscopic study
Authors: Easmann R P. , Steflik D. E. , Pashley D. H. , McKinnny R. V. , Whitford G. M.
Published: April 2006

This paper describes the ultrastructural, topographical changes seen in rat gastric mucosa following application of 0.1 N HC1 or 1,10 or 50 niM NaF in 0.1 N HC1 to the stomach. No morphological differences were noticed between the 0.1 N HC1 (control) and 1 mM NaF in 0.1 N HCI specimens. Ten milliomolar NaF in 0.1 N HC1 produced some desquamation of surface mucous epithelial cells while 50 mM NaF produced extensive damage to cells surrounding the gastric gland openings (foveolae) as well as inlerfoveolar cell loss.
Effects of smoking on the prevalence and intraoral distribution of Candida albicans
Authors: Oliver D. E. , Shillitoe E. J.
Published: April 2006

To find out whether smoking affects the prevalence and intraoral distribution of Candida albicans, swabs and saliva samples from 100 healthy persons, smokers and non‐smokers, were cultured for the presence of this fungus. The prevalence was the same (35%) in both smokers and non‐smokers. Among carriers, the mean concentration of C. albicans colony‐forming units in saliva of smokers was twice that of the non‐smokers, and the isolation frequency of C. albicans at each of 5 mucosai sites was also higher in smokers than in non‐smokers. However, a wide variation was found, and these differences were not significant at the 0.05 level. Men were carriers more often than women (p < 0.025), and the mucosal site from which C. albicans was recovered most often was the posterior dorsum of the tongue. Although it has previously been claimed that cigarette smoking influences the carrier state of C. albicans, the present study suggests that the effect is only slight.
Dental abnormalities in aging sand rats (Psammomys obesus)
Authors: Ulmansky M. , Ungar H. , Adlhr J. H.
Published: April 2006

Sand rats transferred from their natural environment to laboratory conditions develop diabetes, cataracts, vertebral lesions, liver tumors, malocclusion and gingival inflammation. In the present study 43 sand rats of different ages were randomly chosen from a colony maintained for 13 years in the laboratory. Macroscopical, microscopical and radiographical examinations of the dental apparatus showed marked abnormalities in animals older than 6 months. The incisors were affected more than molars with an asymmetry between the right and left side of the jaw. Pathological alterations in the incisors included variations in length and curvature, lateral inclination, coronal fractures and pulpal calcifications. The enamel on the buccal aspect of these teeth had a scalloped appearance with corresponding meta‐plastic changes and folding of the ameloblastic layer. Coronal fractures were also found in molar teeth and were accompanied by marked hypercementosis. These changes are consistent with those reported in rodents with induced hormonal imbalance and may be associated with the diabetic state of aging sand rats. These gerbils are suggested as a model for studying the role of age‐related disorders in the pathogenesis of certain dental abnormalities.
Fatty‐acid metabolism in oral mucosal epithelium of the hamster
Authors: Harris R. R. , Mackhnzie I. C.
Published: April 2006

Little is known about the role of lipid metabolism in oral mucosal epithelia, although lipids probably play significant roles in the barrier function and in the production of energy for the various epithelial biosynthetic activities. The metabolic fate of exogenously added 14C‐labelled oleic acid in pure epithelial sheets from hamster cheek‐pouch has been investigated. Significant amounts of the label from the tatty acid were found in phosphatidyl choline, sphingomyelin and triglyceride fractions. Lesser amounts were found in cholesterol, cholesterol ester, ceramide and phosphatidyl ethanolamine. Estimations of the amount of ATP produced by both glycolysis and by fatty‐acid β‐oxidation indicated that the 2 activities were essentially equal, which is in contrast to that reported for the epidermis. The results suggest that the oral mucosal epithelium, like the epidermis, is an active lipid‐metabolizing tissue.
Activation of human gingival collagenase
Authors: Uitto V.‐J. , Elliot I. , Robinson P. J.
Published: April 2006

To study the regulation of collagen degradation in periodontium, human gingival homogenate was incubated at 36°C and the release of hydroxyproline was assayed as a measure of collagenase activity. Phenylmethylsulfonyl fluoride, soybean trypsin inhibitor and scrum albumin inhibited the in vitro collagenolysis while p‐aminophenylmcreuric acetate, a sulfhydryl reagent, increased the degradation. When latent collagenase obtained from gingival fibroblast culture was added to the incubation a marked increase in the collagen degradation was found. This increase was prevented by phenylmethylsulfonyl fluoride. The data suggests that collagenase may exist in gingiva partly in a latent form and its activation may be brought about by 2 mechanisms. A serine proteinase present in tissue may activate collagenase by producing a limited clevage, or the activation may occur through a reaction that involves the sulfhydryl groups of the collagenase molecule.
Histochemical studies on Concanavalin A‐binding in experimental carcinoma of the mouse submandibular gland
Authors: Takai Y. , Hyun K‐H. , Hosaka M. , Murase N. , Mori M.
Published: April 2006

The lectin, Concanavalin A(Con A) has been used to localize specific sugar residues (D‐glucose, D‐mannose and D‐fructose) in premalignant lesions and squamous‐cell carcinomas induced following cryosurgery of the mouse submandibular gland. The original Con A‐horseradish peroxidase (HRP) technique as well as its combination with periodate oxidation and subsequent reduction by borohydrate were used to compare the epithelial elements during submandibular gland carcinogenesis. Granules in the granular convoluted tubule cells which were weakly reactive to the Con A‐HRP method were not present in the premalignant duct like structures. The epithelium of premalignant lesions, duct‐like structures, multicystic lesions, and squamous‐cell carcinomas were positive for the cell‐surface and intercellular substances; and basement membranes and stromal fibers were also positive. The results indicated that throughout malignant transformation of the ductal segments, premalignant epithelia lost Con A‐HRP‐staining granules and that Con A‐binding patterns in induced squamous‐cell carcinomas were similar to those found in squamous‐cell epithelium.
Adenolymphoma: an immunohistochemical study with monoclonal antibodies against lymphocyte antigens
Authors: Caselitz J. , Salfelder A. , Seifert G.
Published: April 2006

Twenty‐two adenolymphomas (Warthin's tumours) were investigated with respect to their lymphoid stroma; 4 were analyzed by monoclonal antibodies against B‐cells and T‐cells. A slight predominance of B‐cells was found. In the T‐cell fraction, the T‐helper cells outnumbered the T‐suppressor cells by a factor of 4. These and other cell types were found in the stroma and in the epithelium. Mast cells were associated with those adenolymphomas having a high proportion of epithelium.
Histochemical observations of lectin‐binding in experimental carcinomas in mouse submandibular glands
Authors: Hosaka M. , Takai Y. , Mukasu N. , Asano K. , Mori M.
Published: April 2006

Peroxidase‐conjugated lectins were used for the histochemical detection of carbohydrates in experimental carcinomas of mouse submandibular glands. Induced carcinomas, 43 lesions from 25 cases, were examined histoehemically with galactose‐binding leetins (PNA and RCA‐I), N‐acetyl‐galactosamine‐binding leetins (DBA and SBA), a fucosc‐binding lectin(UEA‐l), and a N‐acetyl‐glucosamine‐binding lectin (WGA). In non‐ or slightly keratinized squamous‐cell carcinomas, the lectin binding of PNA, RCA‐1, DBA, SBA. and WGA was weak in tumor epithelia, and UEA‐1 binding was slight. In highly keratinized squamous‐cell carcinomas, lectin binding was increased in tumor epithelia, but no reaction was noted in completely keratinized regions. Desquamated materials in lumens of tumors gave an intense stain with leetins. Stromal connective tissue, including collagen fibers and basement membranes stained intensely. Lectin binding to submandibular carcinomas was different from binding to granular convoluted tubules and the striated ducts of the normal submandibular gland.
Morphologic study of jejunal mucosal transplants for the replacement of oral mucosa
Authors: Reichart P. , Löning TH. , Hausamen J.‐E. , Becker J.
Published: April 2006

Biopsies were taken at 8 and 12 weeks and at 6 months from oral jejunal mucosal transplants in 5 patients who had undergone extensive surgery for tumors of the floor of the mouth. Microvaseular anastomosed jejunal mucosa had been used for the primary reconstruction. Histological findings included flattening of the jejunal relief, atrophy and erosion of the epithelium with reduction of jejunal excretion and marginal overlapping of oral mucosa. Immunohistocheniical labelling of the cytoskeleton revealed thai jejunal epithelium does not undergo rapid metaplasia in the course of adaptation to oral mucosa. These findings indicate that the jejunal mucosa does not completely change its architecture and does not adapt to the requirements of the oral cavity after a period of 6 months.
Russell body‐like inclusions in oral B‐lymphomas
Authors: Kurihara K. , Sakai H. , Hashimoto N.
Published: April 2006

Two cases of oral B‐lymphomas with numerous Russell body‐like inclusions arc described. One occurred primarily in the hard palate of a 59‐year‐old female with Sjogren's syndrome, and was diagnosed as lymphoplasmacytoid immunoeytoma by Kiel's classification. The other occurred secondarily in the buccal mucosa of a 44‐year‐old female whose first affected site was orbital soft tissues, and was diagnosed as extramedullary plasmacytoma. The diagnostic problems and the nature of the Russell body‐like inclusions are discussed based on the immunoperoxidase (PAP) method and electron microscopic study. The first patient is well without recurrence 19 months after surgery, while the second patient developed extra‐medullary plasmacytoma in the abdomen 5 months after surgery for the buccal plasmacytoma.
Ultrastructural study of intranuclear tubulo‐filaments in a giant cell tumour of bone in a patient with Paget's disease
Authors: El‐Labban N. G.
Published: April 2006

The intranuclear tubulo‐filaments appearing in giant cells were studied ultrastructurally in a giant cell tumour of bone arising in a patient with Paget's disease. Serial sections have shown the presence of invaginating nuclear membrane around these apparent intranuclear tubulo‐filaments, thus segregating these structures from the nuclear substance proper. Further sectioning showed clear continuity between these tubulo‐filaments and the rest of the cytoplasmic contents. It is found that these apparent intranuclear tubules represent pseudo‐inclusions rather than true intranuclear inclusions.
Salivary gland tumors induced by 32P
Authors: Espinal E. G. , Ubios A. M. , Cabrini R. L.
Published: April 2006

The oncogenic power of 32P was demonstrated in salivary glands. An intraglandular injection of 0.25 mCi of chromic colloidal phosphate (32P) was administered to young adult Wistar rats. Seven months post‐injection, tumors began to appear in the neck region in 64% of the rats. The tumors were sarcomas (50%), carcinomas (35.70%), and carcino‐sarcomas (14.28%).
Recovery of rat gastric mucosa following single fluoride dosing
Authors: Easmann R. P. , Pashley D. H. , Birdsong N. L. , Mckinney R. V. , Whitford G. M.
Published: April 2006

Rats' stomachs were intubated with 0.1 N HCl or 100 mM NaF in 0.1 N HCl and excised after 1, 12, 24, 48 h or 7 days for light microscopy. The NaF solution caused erosive injury to the oxyntic glandular mucosa 1 h after application. Progressive stages of recovery were seen at 12, 24 and 48 h after fluoride dosing. Complete recovery was seen 7 days after exposure to fluoride. The kinetics of the recovery process from fluoride injury appear to he similar to those which have been reported for gastric injury produced by other substances.
in vitro attachment of bacteria to extracts of cementum
Authors: Somerman M. J. , Kagermeir A. S. , Bowers M. R. , Fox P. C.
Published: April 2006

Cementum is a specialized mineralized tissue providing for the attachment of perio‐dontal fibers to the root surface of a tooth. In periodontal disease this connective tissue attachment to the cemental surface is lost. The ability of bacteria to adhere to the root surface, an intial event in the disease process, may be influenced by the organic matrix of cementum. Therefore, an in vitro assay of cell attachment was modified to study bacterial adherence to protein extracts of cementum. Petri dishes coated with the extracts were pre‐incubated in culture media and then bacteria were added. Using this assay, Capnocytophaga‐like species, a gram negative bacterium implicated in periodontal disease, attached preferentially to dishes coated with cemental extracts when compared with Type I collagen or uncoated dishes. This assay system should prove beneficial for studying the attachment of various microorganisms to protein extracts of both normal and diseased cementum. as well as providing insight into the unique attachment properties of cementum.
Modulation of HLA‐DR antigens in the gingival epithelium in vitro by heat‐killed Fusobacterium nucleatum and E. coli lipopolysaccharide
Authors: Walsh L. J. , Seymour G. J. , Bird P. S. , Powell R. N.
Published: April 2006

The in vitro influence of the periodontopathic organism Fusobacierium nucleatum (FN) on gingival tissue was examined using an organ culture system. Treatment of gingival explains obtained from periodontally diseased sites with suspensions of FN, stimulated the expression of HLA‐DR antigens by Langerhans cells (LC) in a dose‐dependent fashion, and produced a maintenance of the LC markers Td and ATPase. Similar effects were seen when E. coli lipopolysaceharide (LPS) was substituted for suspensions of FN. With both FN and LPS the expression of HLA‐DR by gingival keratinocytes was maintained throughout the 72‐h culture period, de‐spite the cytotoxic effects of these agents. Using a variety of immunohistological techniques and a monoclonal antibody specific for the strain of FN used, it was possible to demonstrate the uptake of FN antigens by LC within the gingival epithelium.
Leukocyte migration inhibition in recurrent aphthous ulceration
Authors: Gadol N. , Greenspan J. S. , Hoover C. I. , Olson J. A.
Published: April 2006

Leukocyte inhibitory factor (LIF) production in response to streptococcal antigens and oral mucosa was examined as a possible pathogenic mechanism in recurrent aphthous ulceration (RAU). Mononuclear cells from RAU patients and controls were stimulated with antigens prepared from two species of streptococci and from oral mucosa. Candida albicans and foreskin were tested as control antigens. There‐were some statistically significant differences in leukocyte migration inhibition between patients and controls with some concentrations of Streptococcus sanguis (ATCC 10556) and C. albicans, and a trend toward low migration indices with oral mucosa. However, the roughly equal numbers of patients and controls responding positively to each antigen and the large background variation suggest a lack of biological significance. LIF production did not increase consistently in the early stages and did not correlate with ulcer development in patients studied sequentially. We conclude that LIF production (at least in response to the antigens tested) plays no pathogenic role in RAU. Our data do not support the hypothesis that a specific cell‐mediated sensitivity to streptococcal antigens is involved in RAU.
Pulp capping of dental pulp mechanically exposed to oral microflora: a 1–2 year observation of wound healing in the monkey
Authors: Cox C. F. , Bergenholtz G. , Heys D. R. , Syed S. A. , Fitzgerald M. , Heys R. J.
Published: April 2006

Four adult Rhesus monkeys provided 120 teeth for buccal Class V cavities. Twenty‐nine were non‐exposed controls and 91 were exposed for 3 intervals. All 120 teeth were capped with a hard set Ca(OH)2, medicament, restored with amalgam, 57 evaluated after 1 year and 63 after 2 years. Of the 91 exposed pulps, 45 showed complete healing, 25 showed pulpal inflammation varying from acute to chronic, 12 showed severe pulpal breakdown and abscess formation and 9 were necrotic. No difference was observed in the healing response between the 3 exposure times. New hard tissue formed at, or subjacent to, the medicament in 77 of 91 exposed pulps with a tunnel defect frequently present, running from the medicament interlace to the pulp. This study demonstrates that recurring pulp inflammation observed after 1 & 2 year direct pulp capping, is associated with bacterial contamination.