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:3.2.1.31 (beta-glucuronidase)
7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polymorphonuclear leukocytes (PMNs) invade the cornea following an alkali burn apparently undergoing a respiratory burst and degranulation, which is thought to lead to corneal ulceration. The supernatant obtained from burned Sigma collagen (Miller type 1) or from bovine cornea produced a significant locomotory stimulus to PMNs. Citrate inhibited this locomotory stimulus by 69.5% and 98%, respectively. PMNs were stimulated to undergo a respiratory burst without the concomitant release of beta-glucuronidase when exposed to the supernatant from alkali-burned commercial collagens, or from bovine or porcine corneas. This stimulation is reduced by 72% (Sigma collagen) or 89% (bovine cornea) when the supernatant is dialyzed against distilled water and reinstated when the osmolality is increased. The degree of the respiratory burst is partially dependent on the volume of the supernatant, the duration of alkali exposure, and/or the concentration of NaOH used. The respiratory burst of PMNs stimulated by alkali-burned Sigma collagen supernatant is inhibited by trifluoperazine but not by citrate or EDTA. Light and electron microscopy of these stimulated PMNs show many large blebs and hairlike projections. The authors hypothesize that collagen breakdown product(s) from alkali burning might be the initial, or one of the initial stimuli, for PMN invasion into the cornea and the subsequent activation of the respiratory burst.
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PMID:Alkali-burned collagen produces a locomotory and metabolic stimulant to neutrophils. 859 11

In vivo and in vitro evidence indicates that metabolic acidosis, which may occur prior to complete excretion of end products of metabolism, increases urinary calcium excretion. The additional urinary calcium is almost certainly derived from bone mineral. Neutralization of this daily acid load, through the provision of base, decreases calcium excretion, suggesting that alkali may influence bone calcium accretion. To determine whether metabolic alkalosis alters net calcium efflux (JCa+) from bone and bone cell function, we cultured neonatal mouse calvariae for 48 h in either control medium (pH approximately equal to 7.4, [HCO3-] approximately equal to 24), medium simulating mild alkalosis (pH approximately equal to 7.5, [HCO3-] approximately equal to 31), or severe alkalosis (pH approximately equal to 7.6, [HCO3-] approximately equal to 39) and measured JCa+ and the release of osteoclastic beta-glucuronidase and osteoblastic collagen synthesis. Compared with control, metabolic alkalosis caused a progressive decrease in JCa+, which was correlated inversely with initial medium pH (pHi). Alkalosis caused a decrease in osteoclastic beta-glucuronidase release, which was correlated inversely with pHi and directly with JCa+. Alkalosis also caused an increase in osteoblastic collagen synthesis, which was correlated directly with pHi and inversely with JCa+. There was a strong inverse correlation between the effects alkalosis on osteoclastic beta-glucuronidase release and osteoblastic collagen synthesis. Thus metabolic alkalosis decreases JCa+ from bone, at least in part, by decreasing osteoclastic resorption and increasing osteoblastic formation. These results suggest that the provision of base to neutralize endogenous acid production may improve bone mineral accretion.
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PMID:Metabolic alkalosis decreases bone calcium efflux by suppressing osteoclasts and stimulating osteoblasts. 876 Feb 64

A previous study demonstrated that the acute phase of silica-induced lung injury in rats can be attenuated by concomitant administration of amiodarone, a cationic amphiphilic drug that inhibits phospholipase activity in the lungs. The purpose of the present study was to determine whether continued amiodarone administration could inhibit subchronic silica-induced lung injury and fibrosis. Male Fischer-344 rats were administered amiodarone (150 mg/kg, p.o., 5 days/week) for 14 days and were then instilled with silica (100 mg/kg) intratracheally. Amiodarone treatment then continued for 60 days. Injury was evaluated by parameters in bronchoalveolar lavage fluid and fibrosis was assessed by lung hydroxyproline content and trichrome staining of collagen. Within the bronchoalveolar lavage fluid, amiodarone treatment resulted in significant decreases in silica-induced elevations in albumin levels, lactate dehydrogenase activity, beta-glucuronidase activity, and neutrophil influx. Amiodarone treatment resulted in significant reductions in silica-induced increases in lung weight and hydroxyproline levels; the diminution of fibrosis due to amiodarone treatment was confirmed histologically. These results indicate that subchronic pulmonary inflammation and fibrosis induced by silica in the rat can be attenuated by the concomitant administration of amiodarone.
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PMID:Subchronic pulmonary inflammation and fibrosis induced by silica in rats are attenuated by amiodarone. 883 39

Eleven chalcone derivatives have been tested for their inhibitory effects on platelet aggregation in rabbit platelet suspension and the activation of mast cells and neutrophils. Arachidonic acid-induced platelet aggregation was potently inhibited by almost all the compounds and some also had a potent inhibitory effect on collagen-induced platelet aggregation and cyclooxygenase. Some hydroxychalcone derivatives showed strong inhibitory effects on the release of beta-glucuronidase and lysozyme, and on superoxide formation by rat neutrophils stimulated with the peptide fMet-Leu-Phe (fMLP). We found that the anti-inflammatory effect of 2',5'-dihydroxychalcone was greater than that of trifluoperazine. 2'5'-Dihydroxy and 2',3,4,5'-tetrahydroxyl chalcones, even at low concentration (50 microM), tested in platelet-rich plasma from man almost completely inhibited secondary aggregation induced by adrenaline. These results suggest that the anti-platelet effects of the chalcones are mainly a result of inhibition of thromboxane formation.
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PMID:2',5'-Dihydroxychalcone as a potent chemical mediator and cyclooxygenase inhibitor. 917 90

Metabolic acidosis induces net calcium efflux (JCa+) from cultured bone, in part, through an increase in osteoclastic resorption and a decrease in osteoblastic formation. In humans provision of base as potassium (K+) citrate, but not sodium (Na+) citrate, reduces urine Ca (UCa), and oral KHCO3 decreases bone resorption and UCa in postmenopausal women. Potassium deprivation alone leads to an increase in UCa. To determine whether decreased extracellular K+ concentration ([K+]) at a constant pH, PCO2, and [HCO-3] alters JCa+ and bone cell activity, we measured JCa+, osteoblastic collagen synthesis, and osteoclastic beta-glucuronidase release from neonatal mouse calvariae cultured for 48 h in medium of varying [K+]. Calvariae were cultured in control medium (approximately 4 mM [K+]) or medium with mildly low K+ (MLK, approximately 3 mM [K+]), very low K+ (VLK, approximately 2 mM [K+]), or extremely low K+ (ELK, approximately 1 mM [K+]) (n > or = 9 in each group). Compared with control, ELK, but not MLK or VLK, resulted in a marked increase in JCa+ and an increase in beta-glucuronidase release and a decrease in collagen synthesis. JCa+ was correlated directly with medium beta-glucuronidase activity and inversely with collagen synthesis. To determine whether the reduction in medium [K+] was associated with a decrease in intracellular pH (pHi), we measured pHi in MC3T3-E1 cells, a mouse osteoblastic cell line. Incubation in 1 mM [K+] led to a significant decrease in pHi compared with 3 mM [K+]. Thus incubation in a reduced [K+] medium stimulates JCa+ and osteoclastic enzyme release and inhibits osteoblastic collagen synthesis, which may be mediated by a reduction in bone cell pH.
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PMID:Decreased potassium stimulates bone resorption. 922 39

The present investigation was designed to characterize the biochemical and connective tissue components and to correlate the significance of morphological and biochemical perturbations in cyclophosphamide (CP)-induced lung fibrosis in rats. Lung fibrosis was induced in male Wistar rats by intraperitoneal injection of 20 mg/100 g body weight of CP, and their pneumotoxic derangements were characterized during an early destructive phase followed by a proliferative and synthetic phase. Serum angiotensin-converting enzyme (ACE) activity was higher in CP-treated rats at days 2, 3, 5, 7, and 11, but there was a significant decrease in lung ACE activity during the same time period. Elevated levels of beta-glucuronidase activity were observed in the lung lavage fluid of CP-administered rats days 2, 3, 5, and 7. Lung myeloperoxidase activity was higher in CP rats. Of significance was the presence of collagenase and collagenolytic cathepsin in the lavage fluid of CP rats, when compared with the barely detectable levels in controls. A similar increase in these enzyme activities was also noticed in the lung tissue of CP rats during the same experimental period. Lavage fluid hydroxyproline content was higher in CP rats when compared with controls. Similarly, lung protein and DNA levels were elevated significantly after treatment with CP. The pulmonary histamine and serotonin contents were significantly higher in CP rats. The incorporation of [3H]thymidine into lung total DNA, [3H]proline into lung hydroxyproline, and [35S]sulphate into lung glycosaminoglycan, measured as indicators of lung DNA, collagen, and glycosaminoglycan synthesis, respectively, was also higher in CP groups. Increased levels of hydroxyproline, elastin, hexosamine, total hexose, fucose, sialic acid, and uronic acid in the lungs of rats 14, 28, and 42 days after CP insult were characterized as biomarkers of CP-induced interstitial changes. These findings indicate that CP-induced lung fibrosis results in alterations not only in collagen synthesis and accumulation, but also in glycosaminoglycan and glycoprotein content.
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PMID:Biochemical and connective tissue changes in cyclophosphamide-induced lung fibrosis in rats. 977 51

The effects of electrical stimulation on selected biochemical characteristics and histological structure of the mutton Longissimus dorsi (LD) and Semimembranosus (SM) muscles were studied. Electrical stimulation had significant influence on the histological characteristics such as sarcolemma disruption, nuclear disorganization, contracture banding and cellular tearing. However, sarcomere length, total and free beta-glucuronidase activities as well as collagen characteristics were not significantly affected by electrical stimulation. Different muscles did not influence histological parameters and beta-glucuronidase activities.
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PMID:The effects of electrical stimulation on selected biochemical and histological characteristics of different mutton muscles. 1079 80

This experiment tested the hypothesis that running-induced damage to rat skeletal muscle causes changes in synthesis and degradation of basement membrane type IV collagen and to proteins regulating its degradation. Samples from soleus muscle and red and white parts of quadriceps femoris muscle (MQF) were collected 6 h or 1, 2, 4, or 7 days after downhill running. Increased muscle beta-glucuronidase activity indicated greater muscle damage in the red part of MQF than in the white part of MQF or soleus. In the red part of MQF, type IV collagen expression was upregulated at the pretranslational level and the protein concentration decreased, whereas matrix metalloproteinase-2 (MMP-2), a protein that degrades type IV collagen, and tissue inhibitor of metalloproteinase-2 (TIMP-2), a protein that inhibits degradation, were increased in parallel both at mRNA and protein levels. Type IV collagen mRNA level increased in the white part of MQF and soleus muscle. The protein concentration increased in the white part of MQF and was unchanged in soleus muscle. MMP-2 and TIMP-2 changed only slightly in the white part of MQF and soleus muscle. The changes seem to depend on the severity of myofiber injury and thus probably reflect reorganization of basement membrane compounds.
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PMID:Acute exercise induced changes in rat skeletal muscle mRNAs and proteins regulating type IV collagen content. 1129 46

Talc ore may contain several other minerals including calcite, dolomite, magnesite, tremolite, anthophyllite, antigorite, quartz, pyrophyllite, micas, or chlorites. Talc products are sold in a multitude of grades which have physical or functional characteristics especially suited for particular applications, so occupational and consumer exposures to talc are complex. Epidemiology studies have suggested an association between non-fibrous talc and lung cancer risk. Talc was nominated by the National Institute of Occupational Safety and Health (NIOSH) for study by the NTP because of widespread human exposure and because of the lack of adequate information on its chronic toxicity and potential carcinogenicity. Toxicology and carcinogenicity studies of talc (non-asbestiform, cosmetic grade), a finely powdered hydrous magnesium silicate, were conducted by exposing groups of F344/N rats to aerosols for 6 hours per day, 5 days per week for up to 113 weeks (males) or 122 weeks (females). Groups of B6C3F1 mice were exposed similarly for up to 104 weeks. LIFETIME STUDY IN RATS: Groups of 49 or 50 male and 50 female rats were exposed to aerosols of 0, 6, or 18 mg/m(3) talc until mortality in any exposure group reached 80% (113 weeks for males and 122 weeks for females). These exposures were selected based on 4-week inhalation studies of the terminal lung talc burden in F344/N rats; concentrations greater than 18 mg/m(3) were expected to overwhelm lung clearance mechanisms and impair lung function. These exposure concentrations provided a dose equivalent of 0, 2.8, or 8.4 mg/kg per day for male rats and 0, 3.2, or 9.6 mg/kg per day for female rats. In a special study, additional groups of 22 male and 22 female rats were similarly exposed and examined for interim pathology evaluations or pulmonary function tests after 6, 11, 18, and 24 months and lung biochemistry and cytology studies after 24 months. The talc aerosols had a median mass aerodynamic diameter of 2.7 mm in the 6 mg/m(3) chamber and a median diameter of 3.2 mm in the 18 mg/m(3) chamber, with geometric standard deviations of 1.9 mm. However, there was a 7-week period beginning at study week 11 during which the chamber concentration for the 18 mg/m(3) rats varied from approximately 30 to 40 mg/m(3) because of difficulties with the aerosol concentration monitoring system. Further, there was a 12-week period beginning at approximately week 70 during which there were difficulties in generating the talc aerosol, and the chamber concentrations for rats and mice were substantially lower than the target concentrations. Survival, Body Weights, and Clinical Findings: The survival of male and female rats exposed to talc was similar to that of the controls. Mean body weights of rats exposed to 18 mg/m(3) were slightly lower than those of controls after week 65. No clinical findings were attributed to talc exposure. Pathology Findings: Absolute and relative lung weights of male rats exposed to 18 mg/m(3) were significantly greater than those of controls at the 6-, 11-, and 18-month interim evaluations and at the end of the lifetime study, while those of female rats exposed to 18 mg/m(3) were significantly greater at the 11-, 18-, and 24-month interim evaluations and at the end of the lifetime study. Inhalation exposure of rats to talc produced a spectrum of inflammatory, reparative, and proliferative processes in the lungs. Granulomatous inflammation occurred in nearly all exposed rats and the severity increased with exposure duration and concentration. Hyperplasia of the alveolar epithelium and interstitial fibrosis occurred in or near foci of inflammation in many exposed rats, while squamous metaplasia of the alveolar epithelium and squamous cysts were also occasionally seen. Accumulations of macrophages (histiocytes), most containing talc particles, were found in the peribronchial lymphoid tissue of the lung and in the bronchial and mediastinal Iymph nodes. In female rats, the incidences of alveolar/bronchiolar adenoma, carcinoma, and adenoma or carcinoma (combined) in the 18 mg/m(8 mg/m(3) group were significantly greater than those of controls. The incidences of pulmonary neoplasms in exposed male rats were similar to those in controls. Minor alterations attributed to talc exposure were also observed in the upper respiratory tract. Hyperplasia of the respiratory epithelium of the nasal mucosa in males and accumulation of cytoplasmic, eosinophilic droplets in the nasal mucosal epithelium in male and female rats occurred with a concentration-related increased incidence in the exposed groups. Adrenal medulla pheochromocytomas [benign, malignant, or complex (combined)] occurred with a significant positive trend in male and female rats, and the incidences in the 18 mg/m(3) groups were significantly greater than those of controls. Although adrenal medulla hyperplasia occurred with similar frequency among exposed and control females, the incidences of hyperplasia in exposed males were significantly lower than in controls. Lung Talc Burden: Lung talc burdens of male and female rats exposed to 6 mg/m(3) were similar and increased progressively from 6 to 24 months. Lung talc burdens of females exposed to 18 mg/m(3) also increased progressively from 6 to 24 months, while those of males exposed to 18 mg/m(3) remained about the same after 18 months. Lung burdens were generally proportional to exposure concentration at each interim evaluation. Pulmonary Function, Bronchoalveolar Lavage, and Lung Biochemistry: In exposed male and female rats there was a concentration-related impairment of respiratory function which increased in severity with increasing exposure duration. The impairment was characterized by reductions in lung volume (total lung capacity, vital capacity, and forced vital capacity), lung compliance, gas exchange efficiency (carbon monoxide diffusing capacity), and nonuniform intrapulmonary gas distribution. After 24 months, males exposed to 6 mg/m(3) talc had a significant increase in beta-glucuronidase and polymorphonuclear leukocytes; males exposed 18 mg/m(3) had significant increases in b -glucuronidase, lactate dehydrogenase, alkaline phosphatase, and total protein in bronchoalveolar lavage fluid. All exposed females had significantly increased a-glucuronidase, lactate dehydrogenase, alkaline phosphatase, total protein, and polymorphonuclear leukocytes; 18 mg/m(3) females also had significantly increased glutathione reductase. Viability and phagocytic activity of macrophages recovered from lavage fluid were not affected by talc exposure. Total lung collagen was significantly increased in rats at both exposure concentrations after 24 months, while collagenous peptides in lavage fluid and the percentages of newly synthesized protein from females, but not males, were also significantly increased at the 6 or 18 mg/m(3) levels. In addition, lung proteinase activity, primarily cathepsin D-like activity, was significantly greater in exposed males and females. Rats exposed to talc also had significant increases in collagenous peptides and acid proteinase in lung homogenates. 2-YEAR STUDY IN MICE: Groups of 47 to 49 male and 48 to 50 female mice were exposed to aerosols containing 0, 6, or 18 mg/m(3) talc for up to 104 weeks. These exposures were selected based on 4-week inhalation studies of the terminal lung talc burden in B6C3F1 mice; concentrations greater than 18 mg/m(3) were expected to overwhelm lung clearance mechanisms and impair lung function. These exposure concentrations provide a dose equivalent of 0, 2, or 6 mg/kg per day for male mice and 0, 1.3, or 3.9 mg/kg per day for female mice. In a special study, additional groups of 39 or 40 male and 39 or 40 female mice similarly exposed were examined for interim pathology evaluations, lung biochemistry, and cytology studies after 6, 12, and 18 months of exposure. The talc aerosols had a median mass aerodynamic diameter of 3.3 mm with a geometric standard deviation of 1.9 mm in the 6 mg/m(3) chamber, and a median diameter of 3.6 mm with a geometric standard deviation of 2.0 mm in the 18 mg/m(3) chamber. Further, there was a 12-week period beginning at approximately week 70 during which there were difficulties in generating the talc aerosol, and the chamber concentrations for rats and mice were substantially lower than the target concentrations. Survival, Body Weights, and Clinical Findings: Survival and final mean body weights of male and female mice exposed to talc were similar to those of the controls. There were no clinical findings attributed to talc exposure. Pathology Findings: Inhalation exposure of mice to talc was associated with chronic active inflammation and the accumulation of macrophages in the lung. In contrast to rats, hyperplasia of the alveolar epithelium, squamous metaplasia, or interstitial fibrosis were not associated with the inflammatory response in mice, and the incidences of pulmonary neoplasms in exposed and control groups of mice were similar. Accumulations of macrophages (histiocytes) containing talc particles were also present in the bronchial Iymph node. In the upper respiratory tract, cytoplasmic alteration, consisting of the accumulation of cytoplasmic eosinophilic droplets in the nasal mucosal epithelium, occurred with a concentration-related increased incidence in exposed male and female mice. Lung Talc Burden: Lung talc burdens of mice exposed to 6 mg/m(3) were similar between males and females and increased progressively from 6 to 24 months, except for males at 18 months. The lung talc burdens of mice exposed to 18 mg/m(3) were also similar between the sexes at each interim evaluation. Although the talc burdens of males and females increased substantially from 6 to 24 months, the values at 12 and 18 months were similar. Generally, lung burdens of mice exposed to 18 mg/m(3) were disproportionately greater than those of mice exposed to 6 mg/m(3), suggesting that clearance of talc from the lung was impaired, or impaired to a greater extent, in mice exposed to 18 mg/m(3) than in mice exposed to 6 mg/m(3). Bronchoalveolar Lavage and Lung Biochemistry: Increases in total protein, beta-glucuronidase, lactate dehydrogenase, glutathione reductase, total nucleated cells, and polymorphonuclear leukocytes in bronchoalveolar lavage fluid were observed primarily in mice exposed to 18 mg/m(3), although some parameters were also increased in mice exposed to 6 mg/m(3). The amount of collagenous peptides in lavage fluid and total lung collagen were increased in male and female mice exposed to 18 mg/m(3). Acid proteinase activity, principally cathepsin D-like activity, of lung homogenate supernatant fluid was also significantly increased in mice at the 18 mg/m(3) exposure concentration. CONCLUSIONS: Under the conditions of these inhalation studies, there was some evidence of carcinogenic activity of talc in male F344/N rats based on an increased incidence of benign or malignant pheochromocytomas of the adrenal gland. There was clear evidence of carcinogenic activity of talc in female F344/N rats based on increased incidences of alveolar/bronchiolar adenomas and carcinomas of the lung and benign or malignant pheochromocytomas of the adrenal gland. There was no evidence of carcinogenic activity of talc in male or female B6C3F1 mice exposed to 6 or 18 mg/m(3). The principal toxic lesions associated with inhalation exposure to the same concentrations of talc in rats included chronic granulomatous inflammation, alveolar epithelial hyperplasia, squamous metaplasia and squamous cysts, and interstitial fibrosis of the lung. These lesions were accompanied by impaired pulmonary function characterized primarily by reduced lung volumes, reduced dynamic and/or quasistatic lung compliance, reduced gas exchange efficiency, and nonuniform intrapulmonary gas distribution. In mice, inhalation exposure to talc produced chronic inflammation of the lung with the accumulation of alveolar macrophages. Synonyms: talcum; agalite; emtal 596; non-asbestiform talc; non-fibrous talc; steatite; hydrous magnesium silicate
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PMID:NTP Toxicology and Carcinogenesis Studies of Talc (CAS No. 14807-96-6)(Non-Asbestiform) in F344/N Rats and B6C3F1 Mice (Inhalation Studies). 1261 90

One method of nonviral-based gene therapy is to implant microencapsulated nonautologous cells genetically engineered to secrete the desired gene products. Encapsulating the cells within a biocompatible permselective hydrogel, such as alginate-poly-L-lysine-alginate (APA), protects the foreign cells from the host immune system while allowing diffusion of nutrients and the therapeutic gene products. An important consideration is which kind of cells is the best candidate for long-term implantation. Our previous work has shown that proliferation and differentiation of encapsulated C2C12 myoblasts in vitro are significantly improved by inclusion of basic fibroblast growth factor (bFGF), insulin growth factor II (IGF-II), and collagen within the microcapsules ("enhanced" capsules). However, the effects of such inclusions on the functional status of the microcapsules in vivo are unknown. Here we found that comparing the standard with the enhanced APA microcapsules; there was no difference in the rates of diffusion of recombinant products of different sizes, that is, human factor IX (FIX, 65 kDa), murine IgG (150 kDa), and a lysosomal enzyme, beta-glucuronidase (300 kDa), thus providing a key requirement of such an immunoprotective device. Furthermore, the creatine phosphokinase activity and myosin heavy chain staining (markers for differentiation of the myoblasts) and the cell number per capsule in the enhanced microcapsules indicated a higher degree of differentiation and proliferation when compared to the standard microcapsules, thus demonstrating an improved microenvironment for the encapsulated cells. Efficacy was tested in a melanoma cancer tumor model by treating tumor induced by B16-F0/neu tumor cells in mice with myoblasts secreting angiostatin from either the standard or enhanced APA microcapsules. Mice treated with enhanced APA-microcapsules had an 80% reduction in tumor volume at day 21 compared to a 70% reduction in those treated with standard APA-microcapsules. In conclusion, enhancement of APA microcapsules with growth factors and collagen did not adversely affect their permeability property and therapeutic efficacy. However, the enhanced differentiation and viability of the encapsulated myoblasts in vivo should be advantageous for long-term delivery with this method of gene therapy.
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PMID:Enhancement of myoblast microencapsulation for gene therapy. 1647 Aug 9


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