Proteolytic enzymes

About: Proteolytic enzymes is a research topic. Over the lifetime, 23096 publications have been published within this topic receiving 835544 citations.

Extraction and isolation of a leukotoxin from Actinobacillus actinomycetemcomitans with polymyxin B.

Abstract: A leukotoxin from Actinobacillus actinomycetemcomitans was isolated by a procedure that includes polymyxin B extraction, ion-exchange chromatography, and gel filtration chromatography. The procedure resulted in the recovery of 48% of the toxin with a 99-fold increase in specific activity. The isolated toxin has a molecular mass of 180,000 daltons by gel filtration and 115,000 daltons by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It retains all the major biological characteristics previously documented for crude leukotoxin preparations, including susceptibility to heat and proteolytic enzymes and neutralization by sera from patients with juvenile periodontitis. The isolated leukotoxin destroys human but not rat or guinea pig polymorphonuclear leukocytes and has no apparent effect on human erythrocytes. The availability of the A. actinomycetemcomitans leukotoxin should facilitate studies on its chemistry and mode of action as well as its role in the pathogenesis of human periodontal disease.

Clinical practice guidelines for the prevention and treatment of acute and late radiation reactions from the MASCC Skin Toxicity Study Group.

Abstract: Radiation dermatitis (RD) results from radiotherapy and often occurs within the first 4 weeks of treatment, although late effects also occur. While RD may resolve over time, it can have a profound effect on patients' quality of life and lead to dose modifications. A study group of international, interdisciplinary experts convened to develop RD prevention and treatment guidelines based on evidence from randomized, controlled trials. Evidence-based recommendations were developed after an extensive literature review. Randomized, controlled trials with standardized measurement of outcomes were considered the best evidence, and a majority of the recommendations were formulated from this literature. The adoption of washing with water, with or without a mild soap, and allowing the use of antiperspirants is supported by randomized trials. Use of topical prophylactic corticosteroids (mometasone) is recommended to reduce discomfort and itching. There is some evidence that silver sulfadiazine cream can reduce dermatitis score. There is insufficient evidence to support, and therefore the panel recommends against the use of trolamine, topical sulcrate, hyaluronic acid, ascorbic acid, silver leaf dressing, light-emitting diode lasers, Theta cream, dexpanthenol, calendula, proteolytic enzymes, sulcralfate, oral zinc, and pentoxifylline. Moreover, there is no evidence to support the superiority for any specific intervention in a reactive fashion. For patients with established radiation-induced telangiectasia and fibrosis, the panel suggests the use of pulse dye laser for visual appearance, and the use of pentoxifylline and vitamin E for the reduction of fibrosis.

Proteases from Aspergillus fumigatus Induce Release of Proinflammatory Cytokines and Cell Detachment in Airway Epithelial Cell Lines

Abstract: Aspergillus fumigatus is a pathogen causing diverse respiratory disorders. Several studies have suggested that fungal proteases may play a role in the pathogenicity of fungi. Since the airways are the most common route for entry of A. fumigatus, this study focused on the ability of fungal proteases to induce the release of proinflammatory cytokines and to cause cell detachment in human pulmonary epithelial cell lines. It was shown that fungal serine protease activity induced the production of interleukin (IL)-8 and IL-6 and monocyte chemotactic protein-1 and caused cell detachment in a dose-dependent fashion. Chymostatin, antipain, phenylmethylsulfonyl fluoride, and heat treatment completely inhibited fungal protease activity, cytokine production and cell detachment; antileukoprotease partially inhibited these activities. By causing cell detachment, fungal proteases may decrease the physical barrier function of the epithelium; however, by eliciting a cytokine response, the epithelium may signal the mucosal inflammatory response against A. fumigatus.

Heterogeneity of virulence among strains of Bacteroides gingivalis.

Abstract: The ability of fresh isolates of B. gingivalis to establish abscesses in the mouse model was studied by comparing them with established laboratory strains of B. gingivalis. Eight fresh isolates obtained from plaque associated with periodontal disease and grown under similar conditions as established strains were injected subcutaneously on the back of the mouse. All of these strains produced secondary lesions on the abdomen. Septicemia was associated with seven of the strains. Two commonly used laboratory strains, W50 and W83, also produced secondary lesions and septicemia. Five other laboratory strains produced only localized abscesses. On histologic examination, the strains that produced disseminated disease showed invasion of connective disease by individual bacteria that were not in clumps. The strains that produced localized abscesses were characterized by growing in colonies or clumps in the abscess cavity. Four synthetic enzyme substrates were examined to determine whether the differences between invasive and non-invasive strains were due to differences in proteolytic enzyme production. No differences in enzyme production could be demonstrated with the selected substrates.