Activities of phenylalanine and tyrosine aminotransferases in amycolatopsis methanolica mutants

Amycolatopsis methanolica mutant GH 141-19 is an auxotrophic strain able to grow on glucose mineral media supplemented with L- phenylalanine plus L-tyrosine mixtures at a doubling time of 2.5 hours, while mutant GH 71 can grow in media supplemented with only L- phenylalanine at doubling time of 3 hours. Mono Q FPLC anion exchange chromatography of strain GH 71 revealed the presence of 2-phenylalanine aminotransferase activity peaks, these overlapped with the 2-tyrosine aminotransferase peaks present. In mutant GH 141-19 only single phenylalanine and overlapping tyrosine aminotransferase peaks were observed indicating that mutant GH 141-19 is deficient in the second aromatic amino acid aminotransferase peak

Effect of systemic control and local treatment on collagenase enzyme activity in gingival crevicular fluid of uncontrolled diabetic patients

Collagenase enzyme activity in periodontal disease have an important role in break down of collagen fibres and continuous loss of attachment. Collagenase activity increased in inflamed gingival and gingival sulcular fluid relative to healthy gingival. The enzyme is present in connective tissue cells and in the specific granules of PMN. Also, gram-ve organisms in the gingival cervic appears to stimulate gingival collagenase production. It has been well documented that incidence and severity of periodontal diseases increased in uncontrolled diabetes, probably through alteration in tissue resistance: Also, diabetes stimulates gingival collagenase production mediated, in part, by the hormonal or metabolic alterations in host tissues and the overgrowth of gram-ve organisms in the gingival crevice. So determination of the relationship between the severity of periodontal disease and crevicular fluid collagenase in uncontrolled diabetic patients may be useful for determination of tissue destruction in those patients. The study was performed on 15 adult male patients having advanced marginal periodontitis and uncontrolled diabetes. Gingival index,plaque index, measurement of the amount of gingival fluid and collagenolytic activity in the gingival fluid were measured. After two weeks of controlling the diabetic state the same parameters were taken and subgingival scaling was done. Tow weeks later the same parameters were retaken. The results revealed that the higher collagenolytic activity was found in gingival fluid of uncontrolled diabetic patients. Two weeks after controlling the diabetic state, collagenase activity had decreased significantly. Further significant decrease was observed when subgingival scaling had been performed. It appears that the dramatically elevated collagenase activity in uncontrolled diabetic patients is clearly originated from both the host cells as a result of the diabetic state, and also, from gram-ve organisms in the gingival sulcus where diabetes favor its colonization. The two sources of collagenase should be considered during management of uncontrolled diabetic patients. Both systemic control of diabetes as well as local treatment by thorough scaling are necessary to eliminate a possible destructive mechanism of the periodontium in diabetic patients

Phenotypic identification of T lymphocytes subset in recurrent aphthous stomatitis

Recurrent aphthous stomatitis [RAS] is characterized by recurring ulcers in the oral mucosa as abnormality of the immune response, autoimmune or abnormal immunological reaction to antigens of oral bacterial. The study was conducted on 40 patients; 15 suffering from RAS of the minor and 10 of the major form and 15 students as control. The T lymphocytes were determined by the monoclonal antibodies [OKT] using the indirect immunofluorescent technique of Hoffman. Percentage of cells having surface fluorescence was calculated and the monoclonal antibody coated cells were visualized and enumerated. It was concluded from this study that the two clinical entities of RAS may be of the same immunopathologic etiology, but the difference lies in the T cells subpopulation and the ratio of T helper to T suppressor T4/T8