Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.36 (hyaluronidase)
4,606 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability to demonstrate AMPS in the trabecular region in the normal eye of the Rhesus monkey was shown to be critically dependent upon technical variation. Staining the fixed specimen prior to dehydration and embedding permits the uniform demonstration of AMPS in the trabecular region of the Rhesus monkey and shows it to be hyaluronidase-sensitive. Electron microscopy using the modified technique shows the reaction products to be present within the trabecular band, the intertrabecular spaces, and the canal of Schlemm. More impressive distribution was seen in the basement membrane of trabecular endothelium intimately related to the cell wall and in the ground substance and basement membrane of the endothelium of the inner wall of the canal Schlemm. The technique is also successful in the human eye and suggests a greater abundance of trabecular AMPS in open-angle glaucoma.
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PMID:Demonstration of acid mucopolysaccharides in the trabecular meshwork of the Rhesus monkey. 4 31

Treatment of tissue sections with enzymes wich degrade specific types of glycosaminoglycans should provide a means for localizing glycosaminoglycans in tissue sections. The feasibility of this technique was examined by utilizing endogenously labelled glycosaminoglycans in chick and quail embryos. Less than 8% of the total glycosaminoglycans appear to be lost non-specifically during fixation and dehydration. Both Streptomyces hyaluronidase and chondroitinase ABC degraded more than 90% of their respective substrates and demonstrated minimal non-specific extraction of other glycosaminoglycans. The selectivity of chondroitinase ABC for sulphated glycosaminoglycans was substantially increased by raising the pH of the incubation buffer to 8.6. At this pH, chondroitinase ABC degraded negligible amounts of hyaluronic acid. Use of both Streptomyces hyaluronidase and chondroitinase ABC confirmed that embryonic hyaluronic acid binds Alcian Blue under conditions that were previously believed specific for sulphated glycosaminoglycans. We suggest that this may be due to the increased molecular weight of embryonic hyaluronic acid compared to the hyaluronic acid in adult tissues. The results presented suggest that treatment of adjacent sections with buffer, chondroitinase ABC at pH 8.6, and Streptomyces hyaluronidase and subsequent staining with Alcian Blue provides a method for localizing and quantitating glycosaminoglycans in tissue sections.
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PMID:The histochemical specificity of Streptomyces hyaluronidase and chondroitinase ABC. 8 Mar 94

Dehydration is frequently encountered in elderly patients and hypodermoclysis is an alternative method of parenteral rehydration. Hyaluronidase is classically added to the solution infused subcutaneously. The local effects of hypodermoclysis with or without hyaluronidase were investigated by using a randomized double-blind study in 12 dehydrated elderly patients. Five hundred millilitres of a 5% glucose saline solution was infused subcutaneously in 2 hours in each thigh, (A) with and (B) without 250 U of hyaluronidase. Circumference and temperature of each thigh were assessed before and after the infusion. Color was evaluated after the infusion. The gain in thigh circumference was less in the presence of hyaluronidase, but the other variables did not differ. The patients were thoroughly questioned about pain: no difference was noted between solutions A and B. We conclude that hyaluronidase adds no comfort that justifies its systematic use in the hypodermoclysis of glucose saline solutions.
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PMID:Hypodermoclysis in dehydrated elderly patients: local effects with and without hyaluronidase. 187 41

Many glioma-derived cell lines have the capability of escaping cell-mediated immune attack. One mechanism of escape is the secretion of a hyaluronidase-sensitive mucopolysaccharide coat by these cells. This coat prevents contact and tumor cell killing by specific cytolytic allogeneic lymphocytes. The production of the coat by the tumor cells is stimulated by a macromolecular factor released by peripheral blood mononuclear (PBMC) cells in culture. We have examined the morphologic and ultrastructural features of this extracellular matrix. Three coat-producing lines were studied. Under phase contrast light microscopy, the coat is a clear pericellular 'halo'. To stain this zone, ruthenium red and Alcian Blue 8 G stains, which bind to acid mucopolysaccharides (to a large extent, hyaluronic acid), were used. The two stains produced similar results. With light microscopy, a weblike pattern of stain was evident throughout the halo region. With transmission electron microscopy, staining was found along the plasma membrane of the glioma cells and their microvilli, stretching in long, branching filaments from these surfaces and, in some instances, from one microvillus to the next. Since mucopolysaccharide matrices have a large aqueous component, it was necessary to determine whether dehydration alters the stain pattern. Therefore, undehydrated ruthenium red stained specimens from each culture were embedded in Quetal 651 (Ted Pella, Inc., Tustin, CA), a water soluble plastic. No morphologic differences were noted between the hydrated and dehydrated specimens. This study indicates that numerous long microvilli and a secreted mucopolysaccharide matrix are important structural elements of the lymphocyte-stimulated tumor cell halo in vitro. The mechanism by which the PBMC factor stimulates coat formation and the importance of the coat in in vivo tumor defenses remain to be elucidated.
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PMID:Ultrastructural features of the lymphocyte-stimulated halos produced by human glioma-derived cells in vitro. 242 Sep 43

Many adherent cells in vitro are surrounded by a transparent exclusion zone or halo, several micrometers thick, which red blood cells, bacteria and carbon particles cannot penetrate. This halo is rapidly and specifically removed by hyaluronidase and its high degree of hydration is demonstrated by the fact that, although fixation does not eliminate the halo, solvent dehydration does. This latter observation means that the halo cannot be visualized by conventional electron microscopic techniques. We report here that the exclusion-zone material can, however, be seen in the scanning electron microscope if cells are fixed and frozen rapidly and then freeze-dried. Many cells in cultures from a murine fibrosarcoma or from human embryonic lung treated in this way appear to be covered by a matrix that obscures the microvilli that are visible on critical-point-dried or hyaluronidase-treated, freeze-dried cells. Only where the coat is, for some reason, missing can microvilli be seen on freeze-dried cells. The coat structure varies from amorphous to an assembly of fine fibres approximately 100 nm in diameter and its appearance is very similar to that of small drops of hyaluronic acid (10(-5) micrograms ml-1) treated in the same way. Halo material is fragile and detaches itself from the cell surface within an hour of fixation. These observations suggest that the halo phenomenon reflects only the production of extracellular matrix and its turnover. The fragility of the haloes implies that, if they do exist in vivo, they are unlikely to play any structural role. The results suggest that the technique will yield information on other highly hydrated, unstable structures.
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PMID:Morphology of hyaluronidase-sensitive cell coats as seen in the SEM after freeze-drying. 661 10

Although up to several microns thick, the pericellular matrix is an elusive structure due to its invisibility with phase contrast or DIC microscopy. This matrix, which is readily visualized by the exclusion of large particles such as fixed red blood cells is important in embryonic development and in maintenance of cartilage. While it is known that the pericellular matrix which surrounds chondrocytes and a variety of other cells consists primarily of proteoglycans and hyaluronan with the latter binding to cell surface receptors, the macromolecular organization is still speculative. The macromolecular organization previously could not be determined because of the collapse of the cell coat with conventional fixation and dehydration techniques. Until now, there has been no way to study the dynamic arrangement of hyaluronan with its aggregated proteoglycans on living cells. In this study, the arrangement and mobility of hyaluronan-aggrecan complexes were directly observed in the pericellular matrix of living cells isolated from bovine articular cartilage. The complexes were labeled with 30- to 40-nm colloidal gold conjugated to 5-D-4, an antibody to keratan sulfate, and visualized with video-enhanced light microscopy. From our observations of the motion of pericellular matrix macromolecules, we report that the chondrocyte pericellular matrix is a dynamic structure consisting of individual tethered molecular complexes which project outward from the cell surface. These complexes undergo restricted rotation or wobbling. When the cells were cultured with ascorbic acid, which promotes production of matrix components, the size of the cell coat and the position of the gold probes relative to the plasma membrane were not changed. However, the rapidity and extent of the tethered motion were reduced. Treatment with Streptomyces hyaluronidase removed the molecules that displayed the tethered motion. Addition of hyaluronan and aggrecan to hyaluronidase-treated cells yielded the same labeling pattern and tethered motion observed with native cell coats. To determine if aggrecan was responsible for the extended configuration of the complexes, only hyaluronan was added to the hyaluronidase-treated cells. The position and mobility of the hyaluronan was detected using biotinylated hyaluronan binding region (b-HABR) and gold streptavidin. The gold-labeled b-HABR was found only near the cell surface. Based on these observations, the hyaluronan-aggrecan complexes composing the cell coat are proposed to be extended in a brush-like configuration in an analogous manner to that previously described for high density, grafted polymers in good solvents.
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PMID:The dynamic structure of the pericellular matrix on living cells. 827 5

The uppermost superficial surface layer of articular cartilage, the 'lamina splendens' which provides a very low friction lubrication surface in articular joints, was investigated using atomic force microscopy (AFM). Complementary specimens were also observed under SEM at -10 degrees C without dehydration or sputter ion coating. Fresh adult pig osteochondral specimens were prepared from the patellas of pig knee joints and digested with the enzymes, hyaluronidase, chondroitinase ABC and alkaline protease. Friction coefficients between a pyrex glass plate and the osteochondral specimens digested by enzymes as well as natural (undigested) specimens were measured, using a thrust collar apparatus. Normal saline, hyaluronic acid (HA) and a mixture of albumin, globulin, HA (AGH) were used as lubrication media. The surface irregularities usually observed in SEM studies were not apparent under AFM. The articular cartilage surface was resistant to hyaluronidase and also to chondroitinase ABC, but a fibrous structure was exhibited in alkaline protease enzymes-digested specimens. AFM analysis revealed that the thickness of the uppermost superficial surface layer of articular cartilage was between 800 nm and 2 microm in adult pig articular cartilage. The coefficient of friction (c.f.) was significantly higher in chondroitinase ABC and alkaline protease enzymes digested specimens. Generally, in normal saline lubrication medium, c.f. was higher in comparison to HA and AGH lubrication media. The role of the uppermost, superficial surface layer of articular cartilage in the lubrication mechanism of joints is discussed.
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PMID:Role of uppermost superficial surface layer of articular cartilage in the lubrication mechanism of joints. 1155 3

Cultured mammalian cells appeared to express specific particles on their surface, which could be detected by their ability to nucleate ice crystals (I-centers) in a newly developed, two-dimensional crystallization assay. Their expression required approximately 24 h independent of cell density, and metabolic energy, and the number and distribution of the I-centers were cell-type specific. Their characteristic ability to nucleate ice crystals was highly sensitive to dehydration, to hyaluronidase and phospholipase C, but not to a number of proteases such as trypsin, chymotrypsin, collagenase, and pronase. However, these proteases, especially pronase, were able to detach the I-centers from the cell surface, without destroying their ability to nucleate ice crystals. I-centers were specific products of live cells, located in relatively small numbers at the cell surface organized in a detachable, sheet-like structure. We propose to consider the ice nucleating ability of I-centers as an expression of their ability to influence the water structure in the surface of cells. Even though their biological function is not known at this time, as water-structuring centers they appear remarkable enough to warrant our attention.
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PMID:Water structuring centers of mammalian cell surfaces. 1224 43

We report here our retrospective observations on the use of recombinant human hyaluronidase (rHuPH20) for the facilitation of subcutaneous hydration and drug infusion. Thirty-two patients were treated with rHuPH20 in a hospice setting over a 6-month period. Of these, 26 received this agent to enhance hypodermoclysis with standard hydration fluids for symptom control of delirium, myoclonus and mild to moderate dehydration. Flow rates up to 500 mL/hr were attained without difficulty. Electrolyte replacement in hydration fluid was achieved without incident in 5 patients receiving potassium and in 1 patient receiving both potassium and magnesium. In addition to use for hydration, 6 patients received recombinant human hyaluronidase to enhance subcutaneous infusion of 9 medications, primarily because the medication dosage required subcutaneous flow rates greater than the standard 3 mL/hr. There were no significant adverse events. Induration at the infusion site occurred in 1 patient receiving hydration and higher than expected serum lidocaine concentration was observed in another patient. Based on our positive initial experience with recombinant human hyaluronidase, there is interest in expanding its use in our facility in both the inpatient and outpatient settings.
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PMID:Initial experiences with subcutaneous recombinant human hyaluronidase. 1780 4

Dehydration in clinical practice, as opposed to a physiological definition, refers to the loss of body water, with or without salt, at a rate greater than the body can replace it. We argue that the clinical definition for dehydration, ie, loss of total body water, addresses the medical needs of the patient most effectively. There are 2 types of dehydration, namely water loss dehydration (hyperosmolar, due either to increased sodium or glucose) and salt and water loss dehydration (hyponatremia). The diagnosis requires an appraisal of the patient and laboratory testing, clinical assessment, and knowledge of the patient's history. Long-term care facilities are reluctant to have practitioners make a diagnosis, in part because dehydration is a sentinel event thought to reflect poor care. Facilities should have an interdisciplinary educational focus on the prevention of dehydration in view of the poor outcomes associated with its development. We also argue that dehydration is rarely due to neglect from formal or informal caregivers, but rather results from a combination of physiological and disease processes. With the availability of recombinant hyaluronidase, subcutaneous infusion of fluids (hypodermoclysis) provides a better opportunity to treat mild to moderate dehydration in the nursing home and at home.
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PMID:Understanding clinical dehydration and its treatment. 1911 58


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