Ultrastructural analysis of the submandibular sialoliths: Raman spectroscopy and electron back-scatter studies.

The aim of work was the epidemiological analysis of the occurrence of sialolithiasis of the submandibular gland in adults and the evaluation of the ultrastructure of salivary stones. The study sample consisted of 44 sialoliths. Analysis of the structure and chemical composition of sialoliths was performed using a Scanning Electron Microscope and Raman Spectroscopy. Comparing our results with the literature we can say that the epidemiology of sialolithiasis has not changed significantly over the past 50 years. A wide variety of sialoliths structure was observed. In 75% (33) cases a layered structure of salivary stones was observed, while in 25% (11) - homogeneous structure. The various distribution of organic and inorganic components was observed among all the analyzed sialoliths. Raman spectroscopy allows for preliminary analysis of the sialoliths structure with only a qualitative assessment of their composition, which significantly reduces the research value of this method. The presence of organic and inorganic compounds in the core and inner layers of the salivary glands stones confirms 2 basic theories of the formation of sialoliths: inflammation and deposition of the inorganic component as a result of disruption of saliva flow in the salivary glands.

Ultrastructural and elemental analysis of sialoliths and their comparison with nephroliths.

AIM: Sialoliths are common in the submandibular gland and its duct system, although their exact cause of formation is still a matter of debate. The aims of this study were to: (a) analyze sialoliths ultrastructurally, and to determine the role of foreign bodies or organic materials in the formation of sialolith nuclei; and (b) compare nephroliths with sialoliths ultrastructurally. METHODS: Three sialoliths and two nephroliths were analyzed ultrastructurally by a scanning electron microscope and X-ray diffractometer. RESULTS: The main structures of the sialoliths were found to be hydroxyapatite crystals. No organic cores were observed in the central parts of the sialoliths. In nephroliths, calcium oxalate, calcium phosphate, and struvite crystals were found. The energy-dispersive X-ray microanalysis found that sialoliths and nephroliths were predominantly composed of elements comprising calcium, phosphorous, magnesium, sodium, chloride, silicon, iron, and potassium. CONCLUSION: Sialoliths in the submandibular salivary glands might form secondary to sialadenitis, but not via a luminal organic nidus.

Possible etiology of calculi formation in salivary glands: biophysical analysis of calculus.

Sialolithiasis is one of the common diseases of the salivary glands. It was speculated that, in the process of calculi formation, degenerative substances are emitted by saliva and calcification then occurs around these substances, and finally calculi are formed. However, the exact mechanism of the formation of calculi is still unclear. In this study, we identify some possible etiologies of calculi formation in salivary glands through biophysical analysis. Calculi from 13 patients with submandibular sialolithiasis were investigated by transmission electron microscopy, scanning electron microscopy, X-ray microanalyzer, and electron diffraction. Transmission electron microscopic observation of calculi was performed in the submandibular gland (n = 13). In 3 of the 13 cases, a number of mitochondria-like structures and lysosomes were found near calcified materials. Scanning electron microscopic examination of these materials revealed that there were lamellar and concentric structures and that the degree of calcification was different among the calculi. X-ray microanalysis disclosed the component elements in the calculi to be Ca, P, S, Na, etc., and the main constituents were Ca and P. The calcium-to-phosphorus ratio was 1.60-1.89. Analysis of the area including mitochondria-like structures, lysosomes, and the fibrous structures by electron diffraction revealed the presence of hydroxyapatite and calcified materials. It is speculated that mitochondria and lysosomal bodies from the ductal system of the submandibular gland are an etiological source for calcification in the salivary gland.

Micromorphology of sialoliths in submandibular salivary gland: a scanning electron microscope and X-ray diffraction analysis.

PURPOSE: Sialoliths are common in the submandibular gland and its duct system. The exact cause of formation of a sialolith is still a matter of debate. The aim of this study was to analyze 6 sialoliths ultrastructurally to determine their development mechanism in the submandibular salivary glands. MATERIALS AND METHODS: Six sialoliths retrieved from the hilus and duct of the submandibular salivary glands of 6 patients with sialadenitis were analyzed ultrastructurally by scanning electron microscope and x-ray diffractometer. RESULTS: Scanning electron microscope revealed mainly irregular, partly rudely hexagonal, needle-like and plate-shaped crystals. The cross-section from the surface to the inner part of the sialoliths showed no organic material. X-ray diffraction showed that the sialoliths were composed of hydroxyapatite crystals. Energy dispersive x-ray microanalysis showed that all of the samples contained high levels of Ca and P, and small amounts of Mg, Na, Cl, Si, Fe, and K. CONCLUSION: The main structures of the submandibular sialoliths were found to be hydroxyapatite crystals. No organic cores were observed in the central parts of the sialoliths. In accordance with these preliminary results, sialoliths in the submandibular salivary glands may arise secondary to sialadenitis, but not via a luminal organic nidus.

Estudo estereológico dos ductos granulosos e estriados de glândulas submandibulares de ratos machos e fêmeas / Stereologic study of the convoluted granular tubules and striated ducts of male and female rat submandibular glands

Avaliou-se através de métodos estereológicos, as várias dimensöes dos ductos granulosos e dos ductos estriados de glândulas submandibulares de ratos, de ambos os sexos. Em média, os ductos granulosos representam uma estrutura cilíndrica de 6.096,2cm de comprimento e 37,7µm de diâmetro, com um volume compartimental de 68,4mmü e uma superfície externa total de 67,7cm², e constituída por 595,2x10(5) células com volume celular de 994,5µmü; enquanto que, os ductos estriados representam um túbulo de 1.322,9cm de comprimento e diâmetro de 32,0µm, tendo um volume total de 10,9mmü e uma superfície externa total de 11,8cm², e formado por 185,2x10(5) células com volume celular de 652,6µmü. A análise estatística näo mostrou diferenças entre os sexos, para nenhuma das dimensöes quantificadas

Estudo morfométrico do crescimento de glândulas submandibulares de ratos tratados com isoproterenol. II. Modificaçöes no comportamento dos ductos granulosos / Morphometric study of the rat submandibular glands enlargement induced by isoproterenol. II. Changes in the convoluted granular tubule compartment

Estudou-se através de métodos estereológicos ao microscópio óptico, as modificaçöes que ocorrem no compartimento dos ductos granulosos de glândulas submandibulares de ratos induzidos ao crescimento por injeçöes de cloridrato de isoproterenol por 14 dias. A análise dos resultados obtidos mostrou que as dimensöes morfométricas absolutas do sistema de ductos granulosos, praticamente näo se modificaram durante todo o período de crescimento glandular induzido pelo isoproterenol, assim o seu volume total, o volume celular médio, o número total de células e o comprimento total, mantiveram-se ao redor, respectivamente, de 39mmü, 972µmü, 34x10(6) células e 86m. As únicas dimensöes morfométricas que exibiram modificaçöes estatisticamente significativas foram a sua densidade de volume na glândula e o seu diâmetro externo, ambas no intervalo de 0 a 3 dias de tratamento, quando decresceram, respectivamente, de 48 por cento e 21 por cento. Desse modo, os resultados mostraram que as células serosas dos ductos granulosos, ao contrário das células acinosas, näo exibem o efeito sialadenotrófico quando submetido a tratamento crônico com isoproterenol

Ultrastructural localization of microliths in salivary glands of cat.

Although microliths occur in normal human salivary glands and may be an aetiological factor of sialadenitis, little is known of their natural history. In an attempt to remedy this, we investigated a large archival collection of normal and experimental feline parotid, submandibular and sublingual salivary glands. In submandibular and sublingual glands, microliths were detected ultrastructurally in: all types of acinar secretory cells; myoepithelial cells; ductal cells; lumina; intercellular spaces; basement membrane; stroma; macrophages; multinuclear giant cells; and neutrophils. Microliths were not detected ultrastructurally in parotid glands. Microliths appear to form in acinar cells during autophagy and in stagnant secretory material in lumina. Microliths appear to be removed by secretion in the saliva, discharge from cells laterally and basally, and engulfment by macrophages. There appears to be a turnover of microliths, which possibly is upset by secretory inactivity with a resulting accumulation that leads to localized obstruction and sialadenitis.

Structural analysis of phleboliths and salivary calculi.

Three phleboliths and ten salivary calculi in the submandibular duct were studied with scanning electron microscopy (SEM) and computer aided microanalyser (CMA). The surface of the phleboliths was rather even with some irregularity. According to their surface structure the salivary calculi were divided into three types: the rock-like type, the granular type, and the globular type. The phleboliths were classified into two types according to their cut surface: the calcified-core type, and the uncalcified-core type. The core structure was similar to the surface structure in the calcified-core type of phleboliths, but in the salivary calculi the core structure was different from the surface structure in that the cut surface of the core was an accumulation of circular or polygonal structures forming a honey-comb pattern which was surrounded by small projections distributed radially. On the basis of these results some etiological factors of phleboliths and salivary calculi are discussed.

Ultrastructural and histochemical observations on microcalculi in chronic submandibular sialadenitis.

A search for microcalculi was made in 14 cases of chronic submandibular sialadenitis. Microcalculi were found in all cases. They were within serous acinar cells and ductal cells, within lumina, and interstitially. They were stained variably by periodic-acid/Schiff and Alcian Blue at pH 2.5. Ultrastructural analytical examination showed them to consist of crystals containing calcium and phosphorus. The observations support the possibility that microcalculi form in autophagosomes, enter lumina and occasionally become impacted to produce sialolithiasis and sialadenitis.

Ultrastructural and histochemical observations on intracellular and luminal microcalculi in the feline sublingual salivary gland.

As the genesis of salivary calculi in man has not been established, the fortuitous observation of microcalculi in sublingual glands of cats prompted this study. Microcalculi were seen occasionally within acinar cells and lumina and macrophages, and rarely interstitially. Microcalculi were stained with the periodic-acid/Schiff technique, and acid-phosphatase activity was associated with intracellular microcalculi. Intracellular microcalculi were seen ultrastructurally in acinar cells in membrane-bound vacuoles that also contained debris and sometimes what appeared to be secretory material. X-ray microanalysis showed the microcalculi to consist of crystals containing calcium and phosphorus. The observations suggest that the microcalculi form within autophagosomes in acinar cells by a precipitation of calcium and phosphorus present in degenerate material, and that the microcalculi eventually enter lumina, where they may be discharged in the saliva or retained and enlarge.

[Microanalysis of salivary calculi]. / Microanalyse des calculs salivaires.

Eight salivary calculi were sectioned along a plane of symmetry and the sections studied by microanalysis. Three different regions were observed: a central region with one or several strongly mineralized nuclei, a stratified, less mineralized region with a lower Ca/P ratio and finally a peripheral weakly calcified region. Although inclusions with high silicium or sulfur concentrations were found in all samples, their role in the genesis of calculus is not clear. Most often filamentous mineralized bacteria were observed by scanning electron microscopy on the external stone surface.