Weights of salivary glands in some ruminant animals

The main paired salivary glands were dissected from Blackbuck, Chinese water deer, Reeves' muntjac and Red deer. The parotid glands, which have an important role in regulating ruminal digestion, were heaviest relative to body weight in the species (water deer and Muntjac) that naturally select the most digestible diet.     

Phosphatidylinositol-hydrolysing enzymes in blowfly salivary glands.

The salivary glands of adult blowflies (Calliphora erythrocephala) contain enzymes that hydrolyse phosphatidylinositol, predominantly by a Ca2+-independent deacylation, though a Ca2+-dependent phosphodiesterase (phospholipase C) activity could be detected. The deacylating enzymes could also hydrolyse phosphatidylcholine and phosphatidylethanolamine, and were secreted in the saliva. Homogenization of salivary glands prelabelled with [3H]inositol resulted in a rapid deacylation of the endogenous 3H-labelled phosphatidylinositol; this hydrolysis was unaffected by addition of 5-hydroxytryptamine to the homogenate.     

Activities of the nuclear envelope in the salivary glands of Drosophila

Morphological data are presented concerning the single-membrane-bound vesicles ("oval bodies") associated with the nuclear envelopes of larval salivary gland cells of Drosophila. Data are also presented concerning the existence of cytoplasmic annulate lamellae in these same cells. The mode of formation of these structures, as well as the relationships between them and with other cytoplasmic organelles are described. The possible functional significance of these phenomena is discussed.     

Activities of glycolytic enzymes in some brain areas of thyroidectomized rats and their response to replacement therapy

Glycolytic metabolism has been assessed by studying a set of key enzymes, in anterior cortex, amygdala, hypothalamus septum and hippocampus, in thyroidectomized rats. The reversibility of the changes induced by the thyroidectomy has been assessed by replacement therapy. In thyroidectomized rats the hexokinase activity was significantly decreased in anterior cortex and hypothalamus. The increase in phosphofructokinase and pyruvate kinase activity was probably due to an increase in cellular energy requirements. Hexokinase activity was best restored by treatment with L-thyroxine (T4) or T4+ propylthiouracil (PTU). The low response of pyruvate kinase activity in all treated animals could suggest that this metabolic step is the least reversible.     

Peptidergic innervation of the major salivary glands of the ferret

In parotid, sublingual and submandibular glands of the ferret, morphological correlates were looked for, using immunocytochemistry, to previous physiological findings showing parasympathetic "atropine-resistant" salivary secretion and neuropeptide-evoked salivation in this species. Nerve fibers storing VIP were numerous in association with acini, ducts and blood vessels, while the number of fibers storing substance P was moderate and those containing CGRP and galanin few; also the number of NPY-containing fibers was low around acini and ducts but relatively high around vessels. Sympathectomy eliminated all NPY- and almost all dopamine beta-hydroxylase-containing fibers. Parasympathectomy of the parotid gland resulted in a total loss of the VIP-containing fibers, and a profound reduction in the number of substance P- and CGRP-containing fibers.     

Distinct expression of calnexin in major human salivary glands

Calnexin (Cnx) has been characterized as a membrane-bound protein that transiently interacts in a unique chaperone system with newly synthesized glycoproteins in order to allow the establishment of their proper tertiary and, in most cases, quarternary structures. The aim of the study was to identify and to locate the expression of Cnx in the three major salivary glands of humans by different methods. Strong expression of Cnx protein and mRNA were generally found in serous salivary secretory units. With regard to mucous secretory units, expression of Cnx was only detectable at a low level in mucous acinar cells of sublingual glands, but not of submandibular glands. Expression of Cnx was always preserved in the surface epithelium of intralobar and interlobular duct segments. In addition, expression of Cnx was detected in sebaceous glands of parotid tissues, with a distribution pattern resembling that seen in sebaceous glands of the normal skin. In conclusion, production of saliva is associated with the expression of Cnx. Synthesis of molecules in mucous secretory units is not necessarily associated with a strong Cnx expression, whereas synthesis in serous secretory units apparently is. The tissue-specific Cnx expression is also paralleled by the observation that the secretions produced by the major salivary glands differ in their composition and amount.     

Fine needle aspiration biopsy cytology of major salivary glands

Fine needle aspiration biopsy of the major salivary glands was performed on 160 patients. In 146 patients with satisfactory samples, the cytologic diagnosis was correlated with clinical follow-up and histologic findings. There were 122 benign lesions, including 47 tumors. There were 24 malignant lesions, 10 of which were primary and 14 metastatic. The overall accuracy was 98%. The sensitivity of the technique was 87.5%. There was no false-positive diagnosis. There were three false-negative diagnoses due to sampling errors and inexperience during the initial period of the study. This study documents that needle aspiration biopsy cytology of the salivary glands is accurate, simple, rapid, inexpensive, well tolerated and harmless to the patient.     

Distinct immunohistochemical expression of osteopontin in the adult rat major salivary glands

Osteopontin is a multifunctional protein secreted by epithelial cells of various tissues. Its expression in the adult rat major salivary glands has not yet been studied. We examined osteopontin expression by immunohistochemistry using a well characterized monoclonal antibody. Submandibular glands of young adult male rats (70–100 days old) showed specific expression in secretion granules of granular duct cells but also in cells of the striated ducts and excretory duct. In the major sublingual as well as the parotid gland expression was found solely in the duct system. In addition, a few interstitial-like cells exhibiting very strong immunostaining for osteopontin could be found in either organ. Expression could neither be seen in acinar cells nor in cells of the intercalated ducts. Moreover, in submandibular glands of more aged rats (6- to 7-month old) which show well developed granular convoluted tubules, there was almost exclusive expression of osteopontin in granular duct cells as well as in some interstitial-like cells, but barely in the striated/excretory duct system. Western blot analysis of the submandibular gland showed a specific band migrating at approximately 74 kDa, detectable at both age stages. Osteopontin secreted fom granular duct cells may influence the compostion of the saliva, e.g. thereby modulating pathways affecting sialolithiasis. Its expression in striated duct cells may also hint to roles such as cell–cell attachment or cell differentiation. The cell-specific expression detected in the rat major salivary glands differs in part from that reported in mice, human and monkey.Nicholas Obermüller and Nikolaus Gassler contributed equally to this work.     

Progesterone metabolism by major salivary glands of rat--I. Submandibular and sublingual glands

The metabolism of progesterone by the submandibular and sublingual salivary glands of female (nonpregnant and pregnant) and male rats was studied. The metabolism was in both sexes significantly greater in submandibular than in sublingual glands. Sex differences were not seen in sublingual glands but less metabolism was found in homogenates and microsomal fractions of female (nonpregnant and pregnant) submandibular glands compared to that of males. The metabolism did not differ between pregnant and nonpregnant female rats. The metabolites were mainly 5 alpha-pregnane-compounds. On the basis of the metabolites identified it can be concluded that rat submandibular and sublingual glands contain at least 3 alpha-, 3 beta-, 20 alpha- and 20 beta-hydroxysteroid dehydrogenase, 5 alpha- and 5 beta-steroid hydrogenase and 17 alpha-steroid hydroxylase activity. 5 alpha-steroid hydrogenase activity was significantly higher in all preparations of male submandibular glands than in females. In sublingual glands some enzyme activities showed pregnancy-related decreased.     

Chemosensory proteins, major salivary factors in caterpillar mandibular glands

Research in the field of insect-host plant interactions has indicated that constituents of insect saliva play an important role in digestion and affect host chemical defense responses. However, most efforts have focused on studying the composition and function of regurgitant or saliva produced in the labial glands. Acknowledging the need for understanding the role of the mandibular glands in herbivory, we sought to make a qualitative and semi-quantitative comparison of soluble luminal protein fractions between mandibular and labial glands of Vanessa gonerilla butterfly larvae. Amylase and lysozyme were inspected as possible major enzymatic activities in the mandibular glands aiding in pre-digestion and antimicrobial defense. Although detected, neither of these enzymatic activities was prominent in the luminal protein preparation of a particular type of gland. Proteins isolated from the glands were identified by mass spectrometry and by searching an EST-library database generated for four other nymphalid butterfly species, in addition to the public NCBI database. The identified proteins were also quantified from the data using "Quanty", an in-house program. The proteomic analysis detected chemosensory proteins as the most abundant luminal proteins in the mandibular glands. In comparison to these proteins, the relative amounts of amylase and lysozyme were much lower in both gland types. Therefore, we speculate that the primary role of the mandibular glands in Lepidopteran larvae is chemoreception which may include the detection of microorganisms on plant surfaces, host plant recognition and communication with conspecifics.     

Localization of amylase and mucins in the major salivary glands of the mouse

Summary Antibodies against murine submandibular and sublingual mucins have been raised in rabbits. Both antisera appeared to be specific. Using these antibodies, the mucins were localized in the acinar cells of the submandibular and sublingual glands respectively.The dyed amylopectin method was used to estimate the activity of amylase in the salivary glands. The enzyme was localized either by a starch-substrate film method or with antibodies against purified parotid amylase. The activity of amylase in parotid homogenates is about 1000-fold higher than that in homogenates of either submandibular or sublingual glands, in which the activity was comparable. Amylase was localized in the acinar cells of the parotid gland with both localization techniques. In the sublingual gland, amylase was found predominantly in the stroma around the acini, and there was some evidence that amylase was present in the demilune cells as well. In the submandibular gland, contradictory results were obtained with both techniques. With the starch-substrate film method, amylase activity was found in the granular convoluted tubular cells, whereas immuno-reactive amylase could only be demonstrated in the acinar cells of this gland. It is concluded that in the submandibular gland amylase and mucin are present in the same cell type.     

Noncontrast computed tomography in the diagnosis of tumors of the major salivary glands

Non-contrast computed tomography (CT) of the major salivary glands was made in 127 patients, which revealed 95 space-occupying lesions (88 intraglandular and 7 extraglandular ones). Pleomorphic tumors of the parotid glands are solitary, round, high-density (29.6 +/- 4.2 HU) masses with well-defined, smooth margins. Salivary cysts were characterized by the presence of a dense capsule; the density of cyst contents was 8.0 +/- 2.0 HU. Salivary lipomas had a characteristic tomographic pattern due to the presence of adipose tissue; the lipoma density was -108.3 +/- 7.8 HU. Malignant parotid tumors were characterized by the presence of higher-density masses with irregular shapes and ill-defined, indistinct margins. Benign submandibular gland tumors had no well-defined margins that separated the tumor from the gland; the density of a tumor matched that of the parenchyma; the mean tumor size was 3.6 +/- 1.3 cm; there was an increase in the sizes of the gland as compared to those of the contralateral gland, as well as a displacement of the adjacent soft tissues. Malignant submandibular gland neoplasms tumors were characterized by the presence of inhomogenous lower-density masses with irregular shapes. Enlarged paraglandular lymph nodes were observed. The sensitivity, specificity, and accuracy of native CT in diagnosing space-occupying lesions of the salivary glands were 97.6, 96.4, and 97.6%, respectively.     

Activities of glycolytic enzymes in rapidly proliferating and differentiated C6 glioma cells

Comparisons of glycolytic enzymes between rapidly proliferating and Bt2 cAMP-induced differentiated C6 glioma cells have been made. Rapidly proliferating cells had higher concentrations of glucose-6-phosphate, fructose-6-phosphate and fructose-1,6-bisphosphate compared to morphologically differentiated cells. Under maximally activating conditions, the specific activity and Vmax of hexokinase and phosphofructokinase enzymes were reduced by approximately 3- and 28-fold, respectively, in differentiated cells, without any change in Km values. These results suggest that hexokinase and phosphofructokinase occupy special control positions and the rate of glycolysis is correlated with cellular proliferation of C6 glioma cells.