El aspecto bucal: desarrollo, estructura y función: algunas aplicaciones clínicas / Colección monografías / Bucal appliances: development, structural and function: some clinic applications

Realizá un estudio integral de la cavidad bucal desde el punto de la vista embriológico, fisiológico y anatómico con el fin de aplicar éste conocimiento en forma directa al diagnóstico clínico y radiográfico de las enfermedades de la boca y al manejo quirúrgico de las estructuras anatómicas

Characterization of the binding of Actinomyces naeslundii (ATCC 12104) and Actinomyces viscosus (ATCC 19246) to glycosphingolipids, using a solid-phase overlay approach.

Actinomyces naeslundii (ATCC 12104) and Actinomyces viscosus (ATCC 19246) were radiolabeled externally (125I) or metabolically (35S) and analyzed for their ability to bind glycosphingolipids separated on thin layer chromatograms or coated in microtiter wells. Two binding properties were found and characterized in detail. (i) Both bacteria showed binding to lactosylceramide (LacCer) in a fashion similar to bacteria characterized earlier. The activity of free LacCer was dependent on the ceramide structure; species with 2-hydroxy fatty acid and/or a trihydroxy base were positive, while species with nonhydroxy fatty acid and a dihydroxy base were negative binders. Several glycolipids with internal lactose were active but only gangliotriaosylceramide and gangliotetraosylceramide were as active as free LacCer. The binding to these three species was half-maximal at about 200 ng of glycolipid and was not blocked by preincubation of bacteria with free lactose or lactose-bovine serum albumin. (ii) A. naeslundii, unlike A. viscosus, showed a superimposed binding concluded to be to terminal or internal GalNAc beta and equivalent to a lactose-inhibitable specificity previously analyzed by other workers. Terminal Gal beta was not recognized in several glycolipids, although free Gal and lactose were active as soluble inhibitors. The binding was half-maximal at about 10 ng of glycolipid. A glycolipid mixture prepared from a scraping of human buccal epithelium contained an active glycolipid with sites for both binding specificities.

Salivary flow rates and salivary film thickness in five-year-old children.

The flow rate of unstimulated whole saliva, the volume of saliva in the mouth before (VMAX) and after (RESID) swallowing, and the surface area of the mouth were measured for determination of the average thickness of the salivary film in five-year-old children with primary dentitions. In 30 subjects of each gender, RESID was calculated from the potassium concentration in unstimulated saliva by a dilution technique. VMAX was calculated as the total of RESID plus the volume normally swallowed (the unstimulated salivary flow rate divided by the swallowing frequency). From these children, ten subjects of each gender who had no missing teeth were selected, and impressions were taken for determination of the surface area of the mouth. Aluminum foil, of known weight per unit area, was adapted to the stone models of different regions of the mouth, and the surface areas were calculated from the weights of foil. The unstimulated salivary flow rate was 0.22 +/- 0.14 mL/min, the mean values of RESID and VMAX were 0.38 +/- 0.11 mL and 0.50 +/- 0.15 mL, respectively, and the mean total surface area of the mouth was 117.6 +/- 7.6 cm2. There were no significant differences in these values due to gender. The average thickness of the salivary film in the mouth was calculated to vary between 0.06 and 0.09 mm. Although the values of salivary flow rate, RESID, and VMAX were much lower than those reported for adults, the average thickness of the salivary film was very similar to that in adults.

Significance of DNA content in oral carcinoma.

Standard cytophotometric measurement of DNA in normal, leukoplakic and cancerous oral and oropharyngeal tissues with a Leitz Weitzler Aristophot Cytophotometer showed both 1% and 5% significance in different grades of malignancy and 5% as regards sites of malignancy. The differences were marked in different grades of malignancy and specially with progression of the lesion. Cytophotometry can be useful to diagnose the stages of carcinoma.

Prediction of malignant transformation in oral epithelial lesions by image cytometry.

The value of image analysis in predicting the malignant potential of oral epithelial lesions showing either hyperplasia or dysplasia was investigated; 5-micron formalin-fixed sections of 16 oral epithelial lesions, of which eight had later transformed to carcinoma and eight had not transformed during a follow-up of 10-15 years were studied. The sections were stained with the azure A-Feulgen reaction for nuclear DNA. In each section 200 nuclei of epithelial cells and 20 nuclei of lymphocytes were assessed; all measurements were made blindly. For each nucleus six features related to shape and amount of stain and six features related to chromatin pattern were assessed. For each feature the mean, SD, and interquartile range were determined and used for linear stepwise discriminant analysis. A model of three variables with the most discriminating power was developed. When the jackknifed classification test was applied using this model, the malignant potential of the lesions that later transformed could be predicted with 87.5% accuracy.

Radioautographic demonstration of receptors for epidermal growth factor in various cells of the oral cavity.

Mouse iodinated epidermal growth factor (EGF) was localized by light and electron microscopic radioautography in basal cells of oral epithelium, papillary cells of the enamel organ, periodontal ligament fibroblasts, preodontoblast precursor cells, and preosteoblasts of the alveolar bone of 13-day-old Sprague-Dawley rats. The specificity of binding in these cells was suggested by an observed reduction of about 90% in the labeling when excess unlabeled EGF was injected along with the 125I-EGF. In contrast, fully differentiated cells, such as ameloblasts, odontoblasts, and osteoblasts, were only poorly labeled. Quantitative analysis of the light microscopic radioautographs revealed that the papillary cells had the highest level of labeling (5.5 grains per 100 micron 2 of cell area). The significance of the rather high labeling of the preosteoblasts of the alveolar bone and the fibroblasts of the periodontal ligament is unknown. However, the well-known effect of EGF in producing precocious eruption of teeth may be a consequence of an effect on these two cell types.

[The diagnosis of Gougerot-Sjorgen syndrome in rheumatology. I. Evaul ation of the principal complementary examinations]. / Diagnostic du syndrome de Gougerot-Sjögren en rhumatologie. I. Evaluation des principaux examens complémentaires.

The examination of a patient with Sjögren's syndrome includes evaluation of the eye, the buccal cavity, and a search for certain factors in the blood. Schirmer's blotting-paper test is a good test but is not specific. In addition, a decreased amount of tearing is difficult to interpret after the age of 45. Slit-lamp examination (rose bengal and fluorescein) yields lesions which confirm keratoconjunctivitis due to decreased tearing. The buccal component is difficult to evaluate. A biopsy of the buccal mucosa gives the best results with minimum risk and expense. Nucleotide scanning is sensitive, but less specific. Salivary flow decreases with age. After 60 years of age this decrease can not be interpreted. The chemical composition of tears or of saliva is promising, but it is not yet a part of the usual diagnostic work-up. Of the available laboratory tests, anti-SS-A antibodies and/ or anti-SS-B antibodies are of value, but they are not found consistently.

Differential effects of collagen in oral tissues and skin by protein-energy malnourished newborn rats and lactating dams.

Effects of protein-energy malnutrition were studied in newborn rats and their dams. Upon delivery, dams received 6%, 12% or 20% protein diets. At Day 15 pups received 14C(U)-proline. The posterior tongue, hard palatal mucosa, soft palatal mucosa and skin were analyzed for collagen and counts incorporated (collagen synthesis, that is, the rate of 14C-proline converted to 14C-hydroxy-proline into gingival collagen). These regions of the dams were also removed to study collagen content. Although soft palatal mucosal collagen of newborns in the 6% and 12% protein groups was decreased, that of skin in the 6% protein group was increased. No such differences were observed in tongue and hard palatal mucosa. Counts incorporated was decreased in the tongue, soft palatal mucosa and skin, but not in hard palatal mucosa. Collagen contents of tongue and hard palatal mucosa and skin of the dams showed no differences, whereas that of soft palatal mucosa in the 6% protein groups was increased. Effects of protein-energy malnutrition on oral tissues and skin were therefore different between newborns and lactating dams. Furthermore, one part of oral mucosa is affected differently from other parts of mucosa and in both, degree of malnutrition has different influences.

DNA content in reactive hyperplasia, precancerosis, and carcinomas of the oral cavity. A cytophotometric study.

Cytophotometry has been used to study DNA content in oral epithelial cells of Feulgen-stained specimens from a total of 43 patients: 3 with erythema exudativum multiforme (EEM), 5 with pemphigus, 3 with stomatitis aphtosa, 5 with lichen ruber planus, 8 with leukoplakia, and 19 with carcinomas. In contrast to reactive hyperplasia (EEM, pemphigus, stomatitis aphthosa) leukoplakia has histograms closest to those of carcinoma, with a high percentage of cells in the polyploid regions. This emphasizes the significance of cytophotometry for diagnosis of preneoplastic and neoplastic lesions of the oral cavity.

Effects of smoking on rapid information processing performance.

In this paper two experiments are reported which were designed to investigate the effects of smoking on the performance of a rapid information processing task. The task involves the detection of sequences of three consecutive digits of the same parity from a series of digits presented visually at the rate of 100/min. In the first experiment smoking improved both the speed and accuracy of performance above rested baseline levels, the greatest improvement occurring with the highest nicotine and tar delivery cigarette. In the second experiment smoking again improved the speed and accuracy of performance above baseline levels, while performance deteriorated over time after not smoking as well as after smoking a nicotine-free cigarette. These findings demonstrate that smoking produces absolute improvements in performance and are explained in terms of the action of nicotine on central cholinergic pathways.

Characterization and distribution of neutral and acidic mucins in the alimentary canal of an Indian freshwater major carp, Catla catla (Hamilton) by histochemical methods.

The distribution and chemical nature of acid and neutral mucins in the various regions of the alimentary canal of Catla catla (Ham.) have been studied. Both acid (sulfated and non-sulfated) and neutral mucins have been found to occur as a mosaic of complex substances in the different mucous cell types (secretory and non-secretory--both mature and immature) in the various regions of the alimentary canal (buccopharynx, oesophagus, intestine, and rectum). Acid mucin (both sulfated and non-sulfated) of the secretory and mature non-secretory mucous cells in the buccopharyngeal and oesophageal regions, however, predominates since these 2 regions are known to participate actively in food lubrication while the sulfated acid mucin keeps the internal mucosa moist. Mucous mother cells which originate from the multipotent progenitor cells contain exclusively neutral mucin in the form of neutral mucopolysaccharide granules. In the course of development these mucous mother cells are gradually pushed towards the periphery of the mucosa and transformed into mature and secretory mucous cells through an intermediate stage--the immature mucous cells. The latter cells during development synthesize intact acid mucopolysaccharide granules which ultimately fuse to produce a compact mass of mucin (both acid and neutral) in the mature and secretory mucous cells.

Distribution of histidine-rich basic protein, a possible keratin matrix protein, in rat oral epithelium.

The indirect fluorescent-antibody technique was used to locate histidine-rich basic protein, filaggrin. In the newborn, immunofluorescence was seen in the cornified layers and in keratohyalin granules throughout the mouth using antibody specific for epidermal filaggrin, a distribution similar to that in epidermis where it is thought that filaggrin functions as the keratin matrix protein. In the adult immunofluorescence was in keratohyalin granules of palate, buccal and tongue epithelium but in the stratum corneum was limited to the soft palate with weak, patchy areas in the densely keratinized epithelium of the hard palate and tongue. Immunofluorescence was delineated at the boundary between the soft and hard palates. A protein apparently identical to epidermal filaggrin was identified in extracts of newborn palate by its mobility on sodium dodecyl sulphate-polyacrylamide gels and subsequent reaction with the antibody used for immunofluorescent studies. This protein was not detected in extracts of adult oral epithelia. Both newborn and adult tissues contained high mol. wt cross-reactive protein, suggestive of the filaggrin-precursor protein extractable from keratohyalin granules. The distribution of filaggrin was consistent with its function as a keratin matrix protein in the newborn oral epithelium and some less densely keratinized regions of the adult. However, in the adult mouth, filaggrin is not detectable in the stratum corneum of the most densely keratinized regions. Thus, the protein must be lost or its antigenic sites altered with maturation of the animal, depending on the type and extent of keratinization.

The oral apparatus of Tetrahymena. V. Oral apparatus polypeptides and their distribution.

Two-dimensional electrophoresis was used to resolve approximately 162 polypeptides from the isolated oral apparatus of Tetrahymena thermophila. The molecular weight range was between 110 000 and 15 000 Daltons. The polypeptides had apparent isoelectric points between pH 3.3 and pH 7.2. Electrophoretic analysis of isolated ciliary axonemes and fractionated oral apparatuses made possible the assignment of polypeptides to structures within the oral apparatus. Approximately 24 polypeptides, including alpha and beta tubulins, are probable components of the basal body-basal plate complex. At least 5 of the oral apparatus polypeptides, including alpha and beta tubulin, are components of the oral apparatus ciliary axonemes. Approximately 138 polypeptides are components of the oral apparatus framework.