Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.36 (hyaluronidase)
 4,606 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Release of peroxidase from secretory cells of rat lacrimal gland upon cholinergic stimulation was studied in vitro with single lobules and isolated cells (lacrimocytes). Isolated lobules, kept in Eagle's medium, remain structurally intact and reaction product of peroxidase is confined to cisternae of rough endoplasmic reticulum, elements of the Golgi apparatus, and all secretory granules. Morphologically, exocytosis occurs by membrane fusion and discharge of granule content. The highest rate of peroxidase released from lobules is observed at 10(-4) M carbamylcholine. The specific activity of peroxidase released into the medium is fourfold higher as compared to the lobules. Release of peroxidase is suppressed by atropine when added before or after the addition of carbamylcholine. At 4 degrees C, no peroxidase release occurs upon cholinergic stimulation. The exocytotic release of peroxidase is dependent on energy supply, as indicated by substantial inhibition (at 37 degrees C) under anoxic conditions or in the presence of dinitrophenol, KCN, or carboxyatractyloside. Furthermore, the process is sensitive to colchicine and vinblastine. Isolated lacrimocytes, consiting of 95% secretory acinar cells, are prepared by digestion with collagenase, hyaluronidase, and trypsin. They retain the characteristic polarity of secretory cells in situ, and localization of peroxidase is the same as in lobules. Since isolated lacrimocytes respond to cholinergic stimulation in the same way as lobules, the receptors are not damaged by the isolation procedure and appear to be associated directly with the exocrine cell. Oxygen uptake by isolated lacrimocytes is about 14 nmol O2 X min-1 X 10(-6) cells; it is about doubled by uncoupling with dinitrophenol. Oxygen uptake rises by 20-30% above the resting rate upon cholinergic stimulation. This additional uptake is suppressed by atropine or by added cholinesterase, indicating that continuous receptor occupancy may be required for the energy demand by exocytosis. On the basis of the specific activity of peroxidase in the medium, the energy demand resulting from cholinergic stimulation is estimated to be 0.08 mumol ATP (or energy-rich phosphate bonds) per microgram of protein released from the lacrimocytes.
 ...
PMID:Exocytosis in secretory cells of rat lacrimal gland. Peroxidase release from lobules and isolated cells upon cholinergic stimulation. 95 71

A recent hypothesis for the cellular mechanism of fluid secretion by lacrimal acini has been based, in part, on the results of subcellular fractionation analyses of lacrimal gland fragments which had been incubated for a brief period in vitro. An important assumption in those studies was that the ion transporters and neurotransmitter receptors measured in isolated subcellular fractions were associated with membranes derived from the acinar cells, since these comprise the bulk of the lacrimal gland mass. This study was undertaken to validate this assumption. Acinar complexes were isolated from rat exorbital lacrimal glands by digestion with collagenase, hyaluronidase, and DNase. Although terminal intralobular duct segments and myoepithelial cells were occasionally noted, the preparations appeared to be free of larger ducts, blood cells, blood vessels, and interstitial cells. Acinar cells were then disrupted, and the homogenates underwent the fractionation procedure used previously for lacrimal gland fragment preparations. This procedure involved a sequence of analyses by differential sedimentation, isopycnic centrifugation on sorbitol gradients, and partitioning in dextran-polyethyleneglycol two-phase systems. Calculated initial specific activities for sodium/potassium adenosinetriphosphatase (Na+/K(+)-ATPase), alkaline phosphatase, acid phosphatase, and succinate dehydrogenase were identical to those obtained from fragment preparations. Major membrane populations resolved by the sequential analyses, including one believed to represent endoplasmic reticulum membranes, two believed to be derived from the acinar cell basal-lateral membrane, and two believed to be derived from the Golgi complex, corresponded closely to populations resolved from lacrimal fragment preparations. In addition to validating the previous use of lacrimal gland fragment preparations in studies of acinar cell function, these results suggest that preparations of isolated lacrimal acini will be useful for future work on neurotransmitter-receptor regulation and basal-lateral plasma membrane dynamics in the lacrimal gland.
 ...
PMID:Analytic subcellular fractionation of acini from rat lacrimal gland. 217 90

A 12-year-old girl was diagnosed as having mucoepidermoid carcinoma of the lacrimal gland. To our knowledge, only 14 cases of mucoepidermoid carcinoma of the lacrimal gland have been reported in the literature; this is the first case occurring in a child. Clinically, this tumor presented as a painless proptosis with inferonasal displacement of the globe. Histologically, it showed infiltrating lobules of neoplastic cells consisting of epidermoid cells admixed with mucin-containing cells and a mild lymphocytic infiltration in the stroma. The mucous cells stained positively with periodic acid-Schiff, Alcian blue, and mucicarmine dyes, but resisted digestion with hyaluronidase. This case illustrates that one should not exclude any diagnostic possibility just because the patient does not seem to belong to the appropriate age group.
 ...
PMID:Mucoepidermoid carcinoma of the lacrimal gland. Case report and review of the literature. 315 55

Characterization of muscarinic acetylcholine receptors in acinar cells from rat pancreas and lacrimal and parotid glands was achieved by binding of the reversible muscarinic antagonist [3H]quinuclidinyl benzilate (QNB) and the specific alkylating reagent [3H]propylbenzilylcholine mustard (PrBCM) to intact acini or dispersed acinar cells. Binding studies with [3H]QNB showed that acinar cells from pancreas contain 26,400, from parotid 21,400, and from lacrimal gland 25,700 binding sites/cell. To assess molecular size of the receptor in each gland, acini were prepared by digestion with purified collagenase and singly dispersed acinar cells were prepared by a combination of digestion with crude collagenase, hyaluronidase, and alpha-chymotrypsin and divalent cation chelation using EDTA. Muscarinic receptors on acini or dispersed cells were covalently labeled with 5 nM [3H]PrBCM, solubilized directly in hot sodium dodecyl sulfate buffer, and resolved by polyacrylamide gel electrophoresis. When solubilized acini were electrophoresed, a major labeled peak was observed on gels along with a smaller peak of lower apparent molecular weight. For pancreatic acini, the apparent molecular weights of these peaks were 117,600 and 85,700; for parotid acini, 104,800 and 74,500; and for lacrimal acini, 87,200 and 63,100. Addition of muscarinic antagonists to the labeling medium abolished both peaks. When dispersed acinar cells were labeled, the larger peak was eliminated, and all radioactivity was concentrated in a single peak: 87,600 for pancreas, 78,000 for parotid gland, and 62,800 for lacrimal gland. Digestion of prelabeled acini with the mixture of enzymes used to produce dispersed acinar cells similarly shifted all radioactivity into this second peak. Limited digestion of acini or dispersed cells with 1 mg/ml of papain resulted in the disappearance of these higher molecular weight peaks and the appearance of a broad peak at Mr = 40,000. Cells of nonepithelial origin, IM-9 lymphocytes and NG108 neuroblastoma X glioma hybrids, also were labeled with [3H]PrBCM and electrophoresed.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Muscarinic acetylcholine receptor structure in acinar cells of mammalian exocrine glands. 398 Apr 74

In order to achieve an optimal combination of principal and side effects of the various drugs used in local anesthesia, a thorough knowledge of pharmacology, anatomy and physiology is essential. The properties of the most commonly used short-acting (Lidocain) medium (Mepivacain) and long-acting (Bupivacain) local anesthetics are described, as well as the effect of the vasoconstrictors Adrenalin and Ornipressin, and of hyaluronidase. The advantages and drawbacks of the different application modalities are discussed. In clinical practice, the surgeon has to be aware of his particular local anesthetic needs at any given time and any stage of the operation, and should attempt to create ideal conditions by careful selection, combination and application of the different drugs. The choice is relatively easy in operations on the globe, the eye muscles and the lacrimal drainage system. In major lid operations, however, greater differentiation in the selection of drugs and methods of application is advisable.
 ...
PMID:[Specific local anesthesia: pharmacology, administration and clinical use (author's transl)]. 626 53

An 18-year-old woman underwent exenteration of the right orbit for tumor recurrence 3 years subsequent to external-beam irradiation for a lacrimal gland tumor diagnosed as an "adenocarcinoma." Light microscopy of the exenteration specimen revealed an acinic cell carcinoma of the lacrimal gland, with a predominant microcystic (latticelike) pattern of growth. Cytoplasmic vacuoles and the secretion within the microcysts stained positive with periodic acid-Schiff with and without alpha-amylase, alcian blue (at a pH of 2.5), mucicarmine, and colloidal iron with and without hyaluronidase. This histochemical staining for epithelial mucins supports the theory that the lacrimal gland, although serous in type, may also function as a modified mucus gland. There was cytoplasmic immunopositivity for keratin (CAM 5.2, KAE 1-3); immunostaining for vasoactive intestinal polypeptide was negative. Electron microscopy disclosed undifferentiated features of intercalated duct cells. We speculate that the lack of immunoreactivity for vasoactive intestinal polypeptide may be correlated with the predominantly undifferentiated intercalated duct cell features observed ultrastructurally.
 ...
PMID:Acinic cell carcinoma of the lacrimal gland. 754 Mar 87

Although generally safe, hyaluronic acid rejuvenation of periorbital tissue has been reported to cause minor and major adverse events. The authors document a case of nasolacrimal duct obstruction due to hyaluronic acid rejuvenation of the tear trough. Nasolacrimal duct obstruction immediately resolved following irrigation of hyaluronidase into the affected lacrimal system. To the authors' knowledge, this is the first reported case of nasolacrimal duct obstruction due to filler injection.
 ...
PMID:Nasolacrimal Duct Obstruction Following Hyaluronic Acid Rejuvenation of the Tear Trough. 3040 98