Histochemical phenotypes of von Ebner's gland of ferret and their functional implications

Organic secretion in ductal cells of the sublingual salivary gland of ferret: Histochemical observations

The presence of organic secretion in ductal cells of the sublingual salivary gland of ferret has been questioned, which prompted the present investigation. Paraffin or cryostat sections from aldehyde fixed or quenched sublingual glands of this species were tested for some amino acid residues, mucosubstances, oxidative and hydrolytic enzymes, and lectins. The glands showed inconspicuous ducts of simple appearances on routine histology. The histochemical procedures, however, revealed a granulated substance in the apical (periluminal) region of ductal cells, which contained tryptophan, disulphides, neutral mucosubstances, αFuc and GalNAc, and showed chloroacetate esterase activity. Occurrence of the substance varied between different ducts of the same gland and/or cells of the same duct. The ductal cells also showed diffuse peroxidase and acid phosphatase, and Golgi-like thiamine pyrophosphatase activities. Acetylcholinesterase-positive nerve fibres embraced the ducts. The results support a particular localisation of protein-bound amino acid residues and enzymatic catalytic activities indicative of organic secretion, possibly tissue kallikrein, in sublingual ductal cells of ferret.

Comparative histochemistry of posterior lingual salivary glands of mouse

Normal posterior deep and superficial salivary glands of tongue were examined in male mice by means of light microscopical histochemistry and neurohistology. Both glands showed acini and simple ducts. Demilunes were present in the superficial gland. Disulphides and neutral mucosubstances occurred in acini and demilunes. Tryptophan staining was seen in acini of the deep gland and demilunes, whereas acid mucosubstances were exclusively localised in the superficial gland. Dehydrogenase activities were widespread. Strong esterase activity occurred throughout the parenchyma of the deep gland and in demilunes; it was variably inhibited by E600, apart from acinar apical regions in the deep gland. Lipase was confined to acini of the deep gland and demilunes. Acid phosphatase staining was similarly localised; it was also seen in periluminal ductal rims of the deep gland, in which ouabain-sensitive Na,K-ATPase was localised basolaterally. Staining for alkaline phosphatase decorated occasional myoepithelial-like arrangements and interstitial capillaries. Acetylcholinesterase was associated with nerve fibres embracing glandular parenchyma. Adrenergic fibres were not seen. The results suggest that the acini of the posterior deep lingual gland secrete neutral glycoproteins, whereas the ducts transport ions and absorb luminal material. The posterior superficial lingual gland mainly secretes acid glycoproteins. Both glands produce lingual lipase, receive cholinergic-type innervation and have inconspicuous myoepithelium.

Salivary acinic cell carcinoma: reappraisal and update

Epidemiologic and clinicopathologic features, therapeutic strategies, and prognosis for acinic cell carcinoma of the major and minor salivary glands are critically reviewed. We explore histopathologic, histochemical, electron microscopic and immunohistochemical aspects and discuss histologic grading, histogenesis, animal models, and genetic events. In the context of possible diagnostic difficulties, the relationship to mammary analog secretory carcinoma is probed and a classification is suggested. Areas of controversy or uncertainty, which may benefit from further investigations, are also highlighted.

Microliths in the parotid of ferret investigated by electron microscopy and microanalysis

The present investigation is an attempt to determine the occurrence, elemental composition and formation of microliths in the parotid of ferret. Parotids from four normal ferrets were examined by electron microscopy and X-ray microanalysis. Crystalline microliths were found in phagosomes of acinar cells, which occasionally contained secretory material, and in phagosomes situated between mitochondria of striated ductal cells. Crystalline microliths and microliths that consisted of granular material either without crystals or mixed with a component of crystals were found in lumina, where they were often associated with cellular debris. The crystals contained calcium and phosphorus. Phagy and stagnation related to pockets of inefficient secretory activity have been previously found to be features of the parotid of ferret. Thus, possibly persistent degradation of redundant cellular material, particularly secretory granules, in phagosomes results in accumulation of calcium and leads to calcified microliths, whereas consolidation of stagnant debris extracellularly does not involve such accumulation and leads to non-calcified or mixed microliths.

Mast Cells in the Salivary Glands and Tongue of the Ferret: Demonstration and Some Histochemical Observations

Previous investigations failed to demonstrate mast cells in the alimentary tract and extraparietal glands of the ferret. It was decided therefore to test this and assess factors that may be of influence. Major salivary glands and tongues of mature ferrets, which had been fixed in formalin-calcium, were examined by means of light microscopical histochemistry. Staining of paraffin sections with techniques depending on basic dyes or esterolytic activity was carried out for conventional times with and without previous oxidation, hot acid hydrolysis, and trypsin and beta-glucuronidase digestion. Aldehyde fuchsin and high iron diamine consistently revealed the presence of few mast cells in interstitial stroma of salivary glands and lingual musculature, and in the lamina propria of lingual mucosa. Alcian blue at 0.5 M MgCl2 and safranin produced less consistent results, and even fewer metachromatic mast cells were detected. No staining of mast cells was obtained with the technique for naphthol AS-D chloroacetate esterase. Pretreatment did not increase the numbers and/or staining reactions of mast cells. The results refute the previous misconception and suggest that ferret is a species with a low incidence of mast cells largely expressing a connective-tissue phenotype.

Histological and histochemical observations on salivary microliths in ferret

The fortuitous observation of salivary microliths in ferret was pursued in the present investigation. Major salivary glands obtained post-mortem from mature ferrets of either sex were examined with the use of histology and light microscopical histochemistry for calcium, protein, amino acids, mucosubstances and hydrolytic enzymes. Microliths were detected in most parotids, but were absent from submandibular and sublingual glands. The microliths were usually seen in lumens, and occasionally in parenchyma and interstices. They were variably stained for calcium, tryptophan, and neutral and acidic mucosubstances, similarly to acinar or ductal secretory granules. Unlike secretory granules, microliths showed autofluorescence, high levels of tyrosine and a low concentration of -SS- groups. Acid phosphatase and beta-glucuronidase reaction surrounded non-luminal microliths. The present data establish ferret as a new model for the investigation of salivary microliths and do not support the notion of microliths being almost absent from the parotid. Probably there is secretory inactivity in ferret parotid and this fosters the formation and accumulation of microliths containing calcium and disintegrated secretory material.

Organic secretory products, adaptive responses and innervation in the parotid gland of ferret: A histochemical study

To qualify cellular events of possible pathophysiological significance in the parotid of ferret, tissue obtained post-mortem from mature animals of either sex was examined by light microscopical histochemistry for calcium, protein, amino acids, mucosubstances and hydrolases, and by neurohistology. Calcium was localised in acinar cells replete with granules containing protein, disulphides and usually carboxylated mucosubstances. Acid phosphatase activity was basally concentrated in the acinar cells. The granular luminal region of striated ductal cells showed protein, tryptophan, disulphides, neutral mucosubstances, and E600-sensitive esterase and Naphthol AS-D chloroacetate esterase activities, whereas their basal region showed acid phosphatase activity. Strong periluminal activity of acid phosphatase and E600-resistant esterase characterised the collecting ducts. Cholinesterase activity was associated with an extensive network of nerve fibres embracing parenchyma. Catecholamine fluorescence was not seen. beta-glucuronidase reactive macrophages abounded in the interstices. The results suggest that while the acini in the parotid of ferret secrete polyionic glycoproteins, shielded by calcium, the striated ducts secrete tryptophan-rich products comprising neutral glycoproteins and showing proteolytic activity. Innervation is of the cholinergic type and parenchymal lysosomal activity, possibly related to autophagy of stored secretory products and heterophagy of luminal material, is brisk. Macrophages contribute to maintaining the glandular microenvironment, wherein secretory activity appears to be lethargic.

Lipolytic and esterolytic activities in posterior lingual glands of rat: a histochemical study

Catalytic activities of lingual lipase were investigated by enzyme histochemistry in post-mortem tongues from male rats. Sections of fresh-frozen or formalin-calcium fixed tissue were incubated with naphthol-AS-nonanoate and alpha-naphthyl acetate substrate mixtures. The effects of pH level, sodium taurocholate activator and E600 inhibitor were also examined. The use of cryostat sections of tissues fixed in formalin-calcium and of nonanoate substrate within the range of pH 4.4-6.4, were optimal for localizing maximum reaction product, captured by Fast Blue BB, in acini and demilunes of the posterior deep and superficial lingual glands respectively. The reaction product corresponded with the distribution of secretory granules and failed to develop when taurocholate was omitted from the incubation medium. Similarly localized E600-resistant reaction product occurred with the acetate substrate and hexazotized New Fuchsin at pH 7.4, in the absence of taurocholate. Lipase and conventional esterase activities appear to be superimposed in posterior lingual glands of rat. The ability of their acini and demilunes to hydrolyse nonanoate substrate at an acidic pH optimum, when activated by sodium taurocholate, seems attributable to lipase destined for secretion into saliva--hence convenient for routine histochemical identification of the enzyme.