Persistence of Epstein-Barr virus in the parotid gland.

Two independent techniques, in situ hybridization on frozen sections and reassociation kinetics, have been used to localize Epstein-Barr virus genomes in tissue samples from healthy human adults. Whereas specimens taken from the palatine tonsils were invariably negative, all samples from the parotid gland were positive when tested with either technique. This observation suggests that the parotid gland is, besides the peripheral lymphocytes, a site of lifelong persistence of Epstein-Barr virus and probably the site of low-level virus production which may be the source of virus found in the oropharynx.     

Uncharted cholinergic nerves in the rabbit parotid gland.

Cholinergic nerves are shown to be left in the rabbit parotid gland after avulsion of the auriculo-temporal nerve: a cholinesterase inhibitor injected through the duct caused secretion, thereby revealing leakage of acetylcholine from cholinergic nerve endings, and acetylcholinesterase positive nerves were found histochemically. The incomplete cholinergic denervation offers an explanation to the fact that some choline acetyltransferase activity remains in the 'denervated' glands.     

Oxygen consumption in the parotid gland

Carbachol, substance P and epinephrine, but not isoproterenol, transiently stimulated O₂ consumption by 40–50% in rat parotid gland slices. The response to carbachol, but not to substance P, was blocked by atropine. Ouabain (1 mM) did not affect the response to carbachol. Also, the response to carbachol did not require external Ca, and was not significantly diminished by 1.0 mM LaCl₃. Reintroduction of Ca to a low Ca medium increased O₂ consumption only if carbachol was present. Procaine inhibited the increase in O₂ consumption due to carbachol, but not that due to substance P. When both carbachol and substance P were presented to the tissues in series and in the absence of external Ca, the second agonist failed to produce a response. When these results are considered in the light of previous studies on Ca and the responses of the parotid gland, they suggest that the primary stimulus for the O₂ consumption is the release of a limited pool of membrane-bound Ca following receptor activation.     

Cystic lesions of the parotid gland

In a series of 708 parotidectomies (partial or total), we found 23 cystic lesions. Of these, 16 met the criteria for so-called "branchial cysts"; five were retention cysts of duct origin, and the remaining two were epidermal inclusion cysts. The principles of diagnosis and treatment of parotid cysts are presented.     

Primary tuberculosis of the parotid gland

A very unusual presentation of Mycobacterium tuberculosis in the parotid gland substance is described to suggest reexamination of the place of tuberculosis in the differential diagnosis of a parotid mass. In this patient, diagnosis was made postoperatively only by histologic examination of the excised specimen. When M. tuberculosis etiology is suspected, either clinically or at operation, culture confirmation should be tried, and a Mantoux test should be performed to complete the investigation.     

Tight junctions in the rat parotid gland

The aim of this study was to elucidate the distribution and morphological changes of tight junctions during secretion in parotid gland acinar cells. Localization of tight junction-associated polypeptide ZO-1, and of tight junction transmembrane protein Occludin, was examined in rat parotid gland by immunofluorescence and immunogold labelling of ultrathin sections. Adult male Sprague-Dawley rats were intraperitoneally injected with IPR and, after 10 and 30 minutes, parotid glands were extirpated. In control specimens, positive immunoreaction for ZO-1 and Occludin was observed on the adluminal side between adjacent cells in the form of narrow elongated profiles corresponding to intercellular canaliculi. After IPR injection, canaliculi became dilated and fluorescence was no longer seen as a continuous line but appeared as an aggregation of separate bright particles. ZO-1 was more widely distributed and was recognized in other areas of the cytoplasm as well. Concurrently, omega-shaped concavities, marked by actin fluorescence, appeared along the intercellular canaliculi. We concluded that, during exocytosis, the selective permeability barrier to the paracellular pathway, based on tight junctions, becomes more leaky, owing to segregation of Occludin caused by intracellular ZO-1 distributional changes associated with actin filaments.     

Oncocytic carcinoma of the parotid gland. A case report

BACKGROUND: Oncocytic carcinoma is a rare malignant tumor of the salivary gland. Abundant, granular, eosinophilic cytoplasm is recognized as an oncocytic feature that reflects an accumulation of mitochondria. Ultrastructural study or immunohistochemical staining using antimitochondrial antibody can confirm the oncocytic nature of the tumor. However, there have been no data on whether immunocytochemical staining for human mitochondria aids in the confirmation of the oncocytic nature of oncocytic carcinoma. CASE: A 61-year-old man presented with a swelling in the left lower cheek. Computed tomography demonstrated a solid, isodense tumor in the parotid gland. An excisional biopsy of the tumor was performed, and an enlarged regional lymph node was removed. Imprint cytology of the lymph node showed cohesive cell clusters with lymphocytes. The clusters were composed of tumor cells that had characteristic abundant, granular cytoplasm and round to oval, centrally or eccentrically located nuclei with increased, fine chromatin and distinct nucleoli. Immunocytochemical staining revealed granular immunoreactivity of the cytoplasm for human mitochondria. Histology demonstrated tumor invasion in the normal gland and adjacent skeletal muscles. All tumor cells showed positive cytoplasm with antimitochondrial antibody by immunohistochemistry. Ultrastructural studies demonstrated packed mitochondria in the cytoplasm of the tumor. CONCLUSION: Immunocytochemical staining for human mitochondria help confirm the oncocytic nature of oncocytic carcinoma in cytologic specimens.     

Cell proliferation in the mouse parotid gland after unilateral parotidectomy.

Unilateral parotidectomy with or without total submandibulectomy has been used to induce cell proliferation in mouse parotid gland. Maximum DNA synthesis and mitosis were recorded four and five days after the operation. The double operation increased the proliferative response. Such proliferative stimulii was not accompanied by secretion and was sex independent. On the other hand, the response decreased with age. RNA and protein synthesis inhibitors showed that the stimulation of DNA synthesis depends on early protein synthesis, which seems to be synthesized on a preexisting template.     

Purification and characterization of phosphofructokinase in bovine parotid gland.

1. Phosphofructokinase (PFK) was purified from bovine parotid gland to 750-fold with the specific activity of 67.5 units/mg protein by Cibacron Blue F3GA affinity chromatography, and TSK DEAE-5PW ion-exchange and TSK G4000SW size exclusion chromatographies on HPLC. 2. On gel-filtration, molecular weight of the native PFK was estimated to 400,000. 3. PFK was a heterotetramer composed of three kinds of subunit with molecular weights of 92,000 (C-type), 88,000 (M-type) and 86,000 (L-type), by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Densitometrically, relative amounts of C-, M- and L-type subunit were 1:1:2. 4. Under the physiological conditions of fructose 6-phosphate (Fru-6-P) and ATP concentrations and pH, PFK activity was suppressed and hardly detectable. 5. Fru-6-P relieved PFK from the ATP inhibition. 6. Fructose 2,6-bisphosphate (Fru-2,6-P2) and AMP activated PFK with a reduction of S0.5 for Fru-6-P and subunit cooperativity. Fru-2,6-P2 was more effective than AMP.     

Calcium-dependent inhibition of protein synthesis in rat parotid gland.

1. Protein synthesis in the rat parotid gland in vitro was studied by measuring the incorporation of [3H]phenylalanine into trichloroacetic acid-insoluble proteins. In the unstimulated gland, the rate of incorporation was dependent on the phenylalanine concentration in the medium and proceeded linearly for up to 3h. 2. Adrenaline, carbamoylcholine, phenylephrine and ionophore A23187 inhibited the incorporation of [3H]phenylalanine into acid-insoluble protein; isoprenaline, dibutyryl cyclic AMP and 8-bromo-cyclic GMP were inactive. 3. Inhibition by adrenaline and carbamoylcholine but not by ionophore A23187 required extracellular Ca2+. 4. Both adrenaline and carbamoylcholine increased the magnitude of the acid-soluble [3H]phenylalanine pool at 10 micrometer extracellular phenylalanine, but had no effect if the phenylalanine concentration was increased to 200 micrometer. 5. There was no correlation between cellular ATP content and the observed inhibition of protein synthesis. 6. Our results suggest that both alpha-adrenergic and cholinergic receptors may play a role in the regulation of protein synthesis in the rat parotid gland, and that their effects are mediated by a rise in intracellular free Ca2+.     

Squamous cell carcinoma of the parotid gland

Squamous cell carcinoma involving the parotid gland is an aggressive and rapidly advancing lesion which if not recognized and treated early will result in a high morbidity and mortality. We reviewed 30 patients with squamous cell carcinoma involving the parotid gland. Twenty-four patients had had previous epidermoid skin lesions in an area known to drain to the parotid gland and three resulted from direct extension into the gland from an overlying skin carcinoma, whereas only three were primary lesions of the gland. Patients who presented with involvement of the gland more than 4 months after excision of the skin lesion had a poor prognosis. Patients with epidermoid skin cancer in areas with a propensity to secondarily involve the parotid gland must be closely followed after treatment of the primary skin lesion.