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:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of the study was to evaluate the effects of a beta 1-selective (atenolol 50 mg q.d.) and a non-selective (propranolol 80 mg b.i.d.) beta-adrenoceptor antagonists on human stimulated parotid and submandibular-sublingual (SM-SL) gland secretion. A randomized double-blind, placebo-controlled cross-over ("Latin square") design was used in 19 healthy male volunteers. Stimulated parotid and SM-SL saliva were sampled immediately before and 7 days after the start of each treatment period. Stimulation of salivary secretion was achieved by use of a 3% citric acid solution. Plasma concentrations of propranolol and atenolol were determined from blood samples. The salivary secretion of both glands was assessed for flow rate, amylase, lysozyme, and salivary peroxidase activity and for concentrations of total protein, hexosamine, sialic acid, Ca2+, Cl-, K+, Mg2+, Na+, and PO4(3-). In both parotid and SM-SL secretions, the total protein and phosphate concentrations and amylase activity were significantly decreased during the two active treatment periods. In SM-SL gland secretion, there were significant changes in potassium and calcium concentrations during active treatment as compared with baseline, with potassium showing a decreased and calcium an increased concentration. During atenolol treatment, salivary peroxidase activity decreased significantly in SM-SL secretion. In parotid secretion, the hexosamine/total protein ratio decreased and the sialic acid/hexosamine ratio increased during atenolol treatment, which may indicate an effect on protein synthesis. No significant effects on salivary secretion rates were disclosed.
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PMID:Effects of the beta-adrenoceptor antagonists atenolol and propranolol on human parotid and submandibular-sublingual salivary secretion. 829 18

Radiation therapy for cancer of the head and neck region often causes salivary gland dysfunction and xerostomia. Several reports suggest that the submandibular/sublingual (SM/SL) glands may be less radiosensitive than the parotid. The purpose of this study was to evaluate differential radiation effects on the major salivary glands. Fifty patients with radiation-induced xerostomia were evaluated (33 males, 17 females; mean age 52.7). The average total tumor dose was 6034 cGy. Major salivary gland function was compared with that of 50 non-irradiated controls. Salivary flow rates included unstimulated and stimulated flows of both the parotid and SM/SL glands. Sialochemical analyses included total protein, lysozyme, lactoferrin, sodium, chloride, and potassium. All four measures of salivary flow were significantly reduced in patients as compared to controls (p = .0001). Like the parotid, submandibular/sublingual gland dysfunction appears to be radiation dose- and field-dependent. Patients in the lowest radiation dose quartile (< or = 5000 cGy) had significantly increased salivary flow compared to those in the highest dose quartile (> or = 6800 cGy; p = .025). Glands that were partially irradiated were more likely to have some residual function than fully irradiated glands (p = .003). Lactoferrin content was increased in parotid saliva of radiation patients (p = .0001). Chloride content was significantly increased also (p = .0001). The SM/SL glands are clearly dysfunctional in post-irradiation xerostomia patients compared to controls, in terms of both flow rates and sialochemistry.
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PMID:Major salivary gland function in patients with radiation-induced xerostomia: flow rates and sialochemistry. 841 81

The salivary composition and flow rate were examined in 20 patients with insulin-dependent diabetes mellitus (IDDM) and in 19 patients with non-insulin-dependent diabetes mellitus (NIDDM) and compared with 20 healthy controls. Resting and stimulated whole and submandibular saliva was analyzed. Significantly lower resting salivary flow rates were found in the IDDM patients as compared to the NIDDM group. In the IDDM patients potassium concentration in resting saliva was significantly higher compared with healthy controls and in stimulated whole saliva compared with NIDDM patients. No difference in salivary total protein, amylase, lactoferrin, or lysozyme was found among the three groups examined. The IgA concentration of the IDDM patients was significantly higher in whole resting saliva compared with controls and in the submandibular saliva compared with both NIDDM patients and controls. No difference was found between controls and the diabetic patients examined in prevalence of complaint of dry mouth. The salivary flow rates, however, were significantly lower in the three subgroups with dry mouth compared with the subgroups without this complaint. Caries were detected in 100% of the diabetic patients and controls. No correlation was observed between the incidence of caries and any of the salivary parameters examined. A higher prevalence and severity of periodontal disease was detected in the diabetic patients as compared to the controls. A significant positive correlation was found between the gingival index and the concentrations of total protein, albumin, lysozyme, and lactoferrin in whole resting saliva in the three groups examined.
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PMID:Oral health and salivary composition in diabetic patients. 848 52

The effects of physiological (saliva and plaque fluid) concentrations of potassium and magnesium and growth phase on lysozyme inhibition of glucose fermentation by S. mutans 10449 were investigated. Glucose fermentations were carried out in a pH-stat at pH 7.0 or 5.5. Cells were at least two times more sensitive to lysozyme in the early-to-middle exponential phase compared with the stationary phase. S. sobrinus 6715 exhibited three-fold greater lysozyme resistance than S. rattus BHT or S. mutans 10449. The concentration of potassium which reduced lysozyme inhibition of S. mutans 10449 fermentation by 50% was 0.2 and 10 mmol/L for stationary and exponential phase cells, respectively. Corresponding values for magnesium were < or = 0.01 and 0.50 mmol/L. Potassium and magnesium exhibited little pH dependence in their reduction of lysozyme inhibition of fermentation by exponential- or stationary-phase S. mutans 10449. The results suggest that: (i) lysozyme interaction with stationary-phase cells involves more non-inhibitory modes than with exponential-phase cells, and (ii) lysozyme may be more effective as an antibacterial agent in saliva than in plaque fluid.
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PMID:Effects of pH, potassium, magnesium, and bacterial growth phase on lysozyme inhibition of glucose fermentation by Streptococcus mutans 10449. 850 Dec 88

The effects of the antihypertensive drug captopril on salivary secretion rate and composition was evaluated in 24 healthy adults (18-46 yr) according to a double-blind, cross-over design. Unstimulated and paraffin-chewing stimulated whole saliva and 3% citric acid stimulated parotid and submandibular-sublingual (SM-SL) secretion were collected at 10.30 a.m. (about 2h after intake of breakfast) on day 0 (baseline values), day 1 (experimental acute values) and day 7 (experimental chronic values) in each treatment period. In 8 of the subjects, also morning samples were collected at 7.30 a.m., with the test subjects in a fasting condition. Whole saliva was assessed for flow rate and for concentrations of sodium, potassium, chloride, calcium and phosphate. In addition, parotid and SM-SL secretion were assessed for concentrations of total protein, hexosamine, sialic acid, lactoferrin and salivary IgA and for activities of amylase, lysozyme and salivary peroxidase. During treatment with the angiotensin converting enzyme inhibitor captopril, the secretion rates tended to increase for unstimulated and paraffin-chewing stimulated whole saliva and for parotid secretion. For salivary composition, no alterations were observed in any of the collected secretions.
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PMID:Effects of the antihypertensive drug captopril on human salivary secretion rate and composition. 874 69

Pulmonary toxicity of ozone (O3) was examined in adult male Fischer 344 rats exposed to 0.5 parts/million O3 for either 6 or 23 h/day over 5 days while maintained at an ambient temperature (Ta) of either 10, 22, or 34 degrees C. Toxicity was evaluated by using changes in lung volumes and the concentrations of constituents of bronchoalveolar lavage fluid that signal lung injury and/or inflammation. Results indicated that toxicity increased as Ta decreased. Exposures conducted at 10 degrees C were associated with the greatest decreases in body weight and total lung capacity and the greatest increases in lavageable protein, lysozyme, alkaline phosphatase activity, and percent neutrophils. O3 effects not modified by Ta included increases in residual volume and lavageable potassium, glucose, urea, and ascorbic acid with exposure at 34 degrees C. Most effects were attenuated during the 5 exposure days and/or returned to normal levels after 7 air recovery days, regardless of prior O3 exposure or Ta. It is possible that Ta-induced changes in metabolic rate may have altered ventilation and, therefore, the O3 doses among rats exposed at the three different Ta levels.
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PMID:Ozone toxicity in the rat. III. Effect of changes in ambient temperature on pulmonary parameters. 890 88

1. The effects of AL0671, a novel potassium channel opener, on protein glycation and low-density lipoprotein (LDL) oxidation were tested. 2. AL0671 dose-dependently inhibited both fluorescence development of bovine serum albumin and cross-linking of lysozyme. These inhibitory effects for glycation were no less potent than aminoguanidine. 3. AL0671 dose-dependently inhibited both increase in negative charge and apo B-100 fragmentation during incubation of LDL with Cu2+. In addition, AL0671 significantly decreased the LDL degradation in rat peritoneal macrophages. 4. Neither pinacidil nor levcromakalim inhibited protein glycation and LDL oxidation. 5. Antioxidant properties of AL0671 might be due to its potent electron-donating ability, and this agent is expected to be useful for hypertensive diabetes.
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PMID:AL0671, a new potassium channel opener, inhibits nonenzymatic glycation of protein and LDL oxidation. 891 39

Ozone (O3) adaptation is a well-known, but poorly understood phenomenon that has been demonstrated in humans and laboratory animals. This study examined pulmonary function and bronchoalveolar lavage fluid (BALF) parameters in O3-adapted F-344 rats to explore possible mechanisms of adaptation. Of particular interest was ascorbic acid (AA), an antioxidant reported to be protective against O3 injury and found to be increased in O3-adapted rats. Adaptation was induced by exposure to 0.25 ppm O3, 12 hr/day for 6 or 14 weeks and evaluated with a challenge test, one that reexposed rats to 1.0 ppm O3 and measured attenuation in the O3 effect on frequency of breathing. Pulmonary function was assessed 1 day postexposure and adaptation and BALF were evaluated 1, 3, and 7 days postexposure. Results showed that forced vital capacity increased over time but decreased due to exposure and that the 14-week, O3-exposed rats had an increase in forced expiratory flow rate. All of the O3-exposed rats that were tested demonstrated adaptation on Postexposure Days 1, 3, and 7, but it was diminished on Day 7. Adaptation was also more pronounced in rats exposed for 14 weeks. Except for AA, BALF levels of total protein, potassium, lysozyme, uric acid, and alpha-tocopherol were unaffected by O3 exposure. Lactic acid dehydrogenase, alkaline phosphatase, glucose-6-phosphate dehydrogenase, and total glutathione were also assayed but were always below detectable limits. Ascorbic acid concentrations were elevated on Days 1, 3, and 7, showing postexposure patterns similar to those found for adaptation. Significant correlation was found between AA concentration and the magnitude of adaptation (r = 0.91, p < 0.002). We conclude that AA may play an important role in mechanisms associated with O3 adaptation in rats.
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PMID:Adaptation to ozone in rats and its association with ascorbic acid in the lung. 899 53

The exudate of fully germinated spores of Clostridium perfringens S40 in 0.15 M KCI-50 mM potassium phosphate (pH 7.0) was found to contain another spore-lytic enzyme in addition to the germination-specific amidase previously characterized (S. Miyata, R. Moriyama, N. Miyahara, and S. Makino, Microbiology 141:2643-2650, 1995). The lytic enzyme was purified to homogeneity by anion-exchange chromatography and shown to be a muramidase which requires divalent cations (Ca2+, Mg2+, or Mn2+) for its activity. The enzyme was inactivated by sulfhydryl reagents, and sodium thioglycolate reversed the inactivation by Hg2+. The muramidase hydrolyzed isolated spore cortical fragments from a variety of wild-type organisms but had minimal activity on decoated spores and isolated cell walls. However, the enzyme was not capable of digesting isolated cortical fragments from spores of Bacillus subtilis ADD1, which lacks muramic acid delta-lactam in its cortical peptidoglycan. This indicates that the enzyme recognizes the delta-lactam residue peculiar to spore peptidoglycan, suggesting an involvement of the enzyme in spore germination. Immunochemical studies indicated that the muramidase in its mature form is localized on the exterior of the cortex layer in the dormant spore. A gene encoding the muramidase, sleM, was cloned into Escherichia coli, and the nucleotide sequence was determined. The gene encoded a protein of 321 amino acids with a deduced molecular weight of 36,358. The deduced amino acid sequence of the sleM gene indicated that the enzyme is produced in a mature form. It was suggested that the muramidase belongs to a separate group within the lysozyme family typified by the fungus Chalaropsis lysozyme. A possible mechanism for cortex degradation in C. perfringens S40 spores is discussed.
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PMID:Molecular characterization of a germination-specific muramidase from Clostridium perfringens S40 spores and nucleotide sequence of the corresponding gene. 915 Feb 12

Rifampicin is an antibiotic mostly used to treat tuberculosis and leprosy, and, occasionally, other diseases. Resistance is due to alterations in membrane permeability or to mutation in the rpoB gene coding for mRNA polymerase. Both these mechanisms originate via chromosomal mutation. However, a rifampicin-resistant Pseudomonas fluorescens strain harboured a multiresistance plasmid which transferred rifampicin resistance when transformed into P. putida or Escherichia coli. Rifampicin readily diffused into the sensitive cells of the E. coli and P. putida recipients, but the transformants with the plasmid, pSCL were resistant to the drug and did not accumulate it. Potassium cyanide restored the diffusion of rifampicin into the resistant cells, indicating that an efflux pump was involved in the resistance mechanism. The resistance of the transformants and the wild strain was also abolished in sphaeroplasts generated by EDTA lysozyme treatment. Analysis of membrane proteins by SDS-PAGE revealed the presence of two new proteins in the plasmid-containing cells of E. coli, P. putida and P. fluorescens and not in the plasmid-free cells. These may be involved in the efflux of rifampicin.
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PMID:Plasmid-mediated rifampicin resistance in Pseudomonas fluorescens. 951 24


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