Effect of a submaxillary gland extract on Ehrlich tumor growth in mice.
(25/1221)
Ablation of host submaxillary glands modifies Ehrlich tumor growth and tumor-infiltrating leukocytes, possibly by modifications in the serum level of growth factors produced by this gland. To extend this research, 7-month-old male EPM-1 mice (N = 30) were divided into two groups: 1) inoculated with tumor cells previously incubated with submaxillary salivary gland extract (SGE) in PBS for 30 min at 37%; 2) inoculated with tumor cells previously incubated with PBS, under the same conditions. Animals were inoculated into the footpad with 40 microl of a suspension containing 4.5 x 10(7) tumor cells/ml, and footpad thickness was measured daily for 10 days. Sections and smears of tumor cells were prepared from the tumor mass to determine mitosis frequency, percent of tumor cells immunopositive to nerve (NGF) and epidermal (EGF) growth factors and percent of tumor-infiltrating leukocytes. The incubation of tumor cells with SGE produced a tumor reduction of about 30% in size (P<0.01). This effect was not related to loss of cell viability during incubation, but a 33% increase (P<0.05) in the percentage of dead or dying tumor cells and a 15% increase in the percent of NGF/EGF-positive tumor cells (P<0.01) were observed in vivo at the end of experiment. Tumor-infiltrating lymphocytes and mitosis frequency did not differ between groups. These data suggest a direct effect of factors present in SGE on tumor cells, which induce degeneration of tumor cells. (+info)
Submandibular gland morphogenesis: stage-specific expression of TGF-alpha/EGF, IGF, TGF-beta, TNF, and IL-6 signal transduction in normal embryonic mice and the phenotypic effects of TGF-beta2, TGF-beta3, and EGF-r null mutations.
(26/1221)
Branching morphogenesis of the mouse submandibular gland (SMG) is dependent on cell-cell conversations between and within epithelium and mesenchyme. Such conversations are typically mediated in other branching organs (lung, mammary glands, etc.) by hormones, growth factors, cytokines, and the like in such a way as to translate endocrine, autocrine, and paracrine signals into specific gene responses regulating cell division, apoptosis, and histodifferentiation. We report here the protein expression in embryonic SMGs of four signal transduction pathways: TGF-alpha/EGF/EGF-R; IGF-II/IGF-IR/IGF-IIR; TGF-betas and cognate receptors; TNF, IL-6, and cognate receptors. Their in vivo spatiotemporal expression is correlated with specific stages of progressive SMG development and particular patterns of cell proliferation, apoptosis, and mucin expression. Functional necessity regarding several of these pathways was assessed in mice with relevant null mutations (TGF-beta2, TGF-beta(3), EGF-R). Among many observations, the following seem of particular importance: (1) TGF-alpha and EGF-R, but not EGF, are found in the Initial and Pseudoglandular Stages of SMG development; (2) ductal and presumptive acini lumena formation was associated with apoptosis and TNF/TNF-R1 signalling; (3) TGF-beta2 and TGF-beta3 null mice have normal SMG phenotypes, suggesting the presence of other pathways of mitostasis; (4) EGF-R null mice displayed an abnormal SMG phenotype consisting of decreased branching. These and other findings provide insight into the design of future functional studies. (+info)
Salivary carbonic anhydrase isoenzyme VI.
(27/1221)
The carbonic anhydrases (CAs) participate in the maintenance of pH homeostasis in various tissues and biological fluids of the human body by catalysing the reversible reaction CO2 + H2O HCO3- + H+ (Davenport & Fisher, 1938; Davenport, 1939; Maren, 1967). Carbonic anhydrase isoenzyme VI (CA VI) is the only secretory isoenzyme of the mammalian CA gene family. It is exclusively expressed in the serous acinar cells of the parotid and submandibular glands, from where it is secreted into the saliva. In this review, we will discuss recent advances in research focused on the physiological role of salivary CA VI in the oral cavity and upper alimentary canal. (+info)
The MR imaging assessment of submandibular gland sialoadenitis secondary to sialolithiasis: correlation with CT and histopathologic findings.
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BACKGROUND AND PURPOSE: MR imaging has been proved to be effective in depicting wide variety of pathologic changes of the salivary gland. Therefore, we evaluated clinical usefulness of MR imaging for sialolithiasis. METHODS: Sixteen patients with sialolithiasis of the submandibular gland underwent MR imaging. MR images of the glands were obtained with a conventional (T1-weighted), fast spin-echo (fat-suppressed T2-weighted) and short inversion time-inversion recovery sequences. Contrast enhancement was not used. MR imaging features then were compared with clinical symptoms, histopathologic features of excised glands, and CT imaging features. RESULTS: Submandibular glands with sialolithiasis could be classified into three types on the basis of clinical symptoms and MR imaging features of the glands. Type I glands were positive for clinical symptoms and MR imaging abnormalities, and were characterised histopathologically by active inflammation (9 [56%] of 16). Type II glands were negative for clinical symptoms and positive for MR imaging abnormalities (4 [25%] of 16), and the glands were replaced by fat. Type III glands were negative for clinical symptoms and MR imaging abnormalities (3 [19%] of 16). CT features of these glands correlated well with those of MR imaging. CONCLUSION: These results suggest that MR imaging features may reflect chronic and acute obstruction, and a combination of CT and MR imaging may complement each other in examining glands with sialolithiasis. (+info)
Further characterization of human salivary anticandidal activities in a human immunodeficiency virus-positive cohort by use of microassays.
(29/1221)
Salivary anticandidal activities play an important role in oral candidal infection. R. P. Santarpia et al. (Oral Microbiol. Immunol. 7:38-43, 1992) developed in vitro anticandidal assays to measure the ability of saliva to inhibit the viability of Candida albicans blastoconidia and the formation of germ tubes by C. albicans. In this report, we describe modifications of these assays for use with small volumes of saliva (50 to 100 microl). For healthy subjects, there is strong inhibition of blastoconidial viability in stimulated parotid (75%), submandibular-sublingual (74%), and whole (97%) saliva, as well as strong inhibition of germ tube formation (>80%) for all three saliva types. The susceptibility of several Candida isolates to inhibition of viability by saliva collected from healthy subjects is independent of body source of Candida isolation (blood, oral cavity, or vagina) or the susceptibility of the isolate to the antifungal drug fluconazole. Salivary anticandidal activities in human immunodeficiency virus (HIV)-infected patients were significantly lower than those in healthy controls for inhibition of blastoconidial viability (P < 0.05) and germ tube formation (P < 0. 001). Stimulated whole-saliva flow rates were also significantly lower (P < 0.05) for HIV-infected patients. These results show that saliva of healthy individuals has anticandidal activity and that this activity is reduced in the saliva of HIV-infected patients. These findings may help explain the greater incidence of oral candidal infections for individuals with AIDS. (+info)
Crystallization of nerve growth factor from mouse submaxillary glands.
(30/1221)
Crystals of the nerve growth factor protein were grown by vapor diffusion from ethanol solution. The crystals are hexagonal, belonging to space group P622 (or its enantiomorph) with a equals 56.1 A, c equals 181.4 A, and V equals 494,400 A. The unit cell contains six molecules of dimeric protein and thus has one monomer per asymmetric unit. The diffraction pattern extends to at least 2.7 A, indicating that this crystal form is suitable for structural analysis to near-atomic resolution. (+info)
Investigation of the prejunctional alpha2-adrenoceptor mediated actions of MDMA in rat atrium and vas deferens.
(31/1221)
1. We have investigated the effects of methylenedioxymethamphetamine (MDMA, 'ecstasy') on peripheral noradrenergic neurotransmission in the rat. 2. In rat atrial slices pre-incubated with [3H]-noradrenaline and in the presence of desipramine (1 micronM) to prevent effects of MDMA on basal outflow of tritium, MDMA (10 micronM) significantly inhibited the release of tritium evoked by short trains of six pulses at 100 Hz every 10 s for 3 min. This effect did not occur in the presence of the alpha2-adrenoceptor antagonist yohimbine (1 micronM). 3. In epididymal portions of rat vas deferens in the presence of nifedipine (10 micronM), MDMA produced a concentration-dependent inhibition of single pulse nerve stimulation-evoked contractions with a pD2 of 5.88+/-0.16 (n=4). Inhibitory effects of MDMA were antagonized by the alpha2-adrenoceptor antagonist yohimbine (0.3 micronM), but not by the 5-hydroxytryptamine receptor antagonist cyanopindolol in a concentration (1 micronM) which markedly antagonized the inhibitory actions of the 5-HT-1 receptor agonist 5-carboxamidotryptamine. 4. In prostatic portions of rat vas deferens in the presence of cocaine (3 micronM), MDMA produced a concentration-dependent inhibition of single pulse nerve stimulation-evoked contractions with a pD2 of 5. 12+/-0.21 (n=4). In the absence of cocaine, only the highest concentration of MDMA (30 micronM) produced an inhibition, but the alpha2-adrenoceptor antagonist yohimbine (0.3 micronM) converted the response to MDMA from inhibition to potentiation of the stimulation-evoked contraction. 5. In radioligand binding studies, MDMA showed similar affinities for alpha2B, alpha2C and alpha2D-adrenoceptor sites, with pKi values of 5.14+/-0.16, 5.11+/-0. 05 and 5.31+/-0.14, respectively. 6 It is concluded that MDMA has significant alpha2-adrenoceptor agonist actions. (+info)
Abundant secretory lipocalins displaying male and lactation-specific expression in adult hamster submandibular gland. cDNA cloning and sex hormone-regulated repression.
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We have previously identified massively expressed 24- and 20.5-kDa male-specific proteins in submandibular salivary glands (SMG) of adult hamsters. Here we report the cloning of the cDNA encoding the 24-kDa protein which we have now found to be a heterogenously N-glycosylated form of the 20.5-kDa protein. The deduced amino acid sequence indicated that the protein is a member of the lipocalin family, the two most related lipocalins being rat odorant-binding protein of nasal mucosa and aphrodisin, a pheromonal protein present in vaginal discharge and saliva of female hamsters. Northern blot analysis showed that cognate mRNA is expressed in hamster SMG and lacrimal gland (LG) displaying marked sex-hormonal repression. The sex-hormonal repression patterns showed similarities and dissimilarities between SMG and LG but they were, respectively, similar to the sex-hormonal repression pattern noted for the SMG 24/20.5-kDa male-specific proteins and for an abundant female-specific 20-kDa LG secretory protein. These SMG and LG proteins were found to be immunologically similar and secretion of the SMG proteins in saliva and their excretion in urine was detected. The male-specific and abundant expression of the SMG proteins were seen at and after sexual maturity but was not dependent on androgens. Surprisingly, a temporary male-like expression of these SMG proteins was seen in lactating females which was obliterated by oestrogen administration. Our results show that despite differences in their repression by sex hormones, the gene for SMG 24/20.5-kDa proteins is similar or identical to that of LG 20-kDa protein and their marked repression by both androgens and oestrogens might be at the transcriptional level. Moreover, they might be excellent models with which to study sex hormone repression of gene expression at the molecular level. The results of homology search and the male- and lactation-specific pressure of the SMG proteins in adult saliva and urine suggests a possibility of their involvement in olfaction-mediated chemical communication between hamsters. (+info)