Effects of laser biostimulation on the epithelial tissue for keratinized layer differentiation: an in vitro study.

Gingival augmentation techniques proposed in the international literature do not exclude a surgical component, which determines consequent post-surgical discomfort and results are not always predictable. In recent years, the introduction of laser biostimulation has led to a less invasive approach, particularly in the treatment of periodontally compromised patients, limiting the surgical phase to seriously compromised cases, with regeneration techniques for the restoration of a correct periodontal tissue anatomy. The aim of this in vitro study is to establish the validity of laser biostimulation in order to develop the epithelial keratinized layer of the tissue by stimulating fibroblasts-keratinocytes organotypic cultures and fibroblasts and keratinocytes mono-cultures. We created two groups (test and control), each one composed of 3 fibroblast cultures, 3 keratinocyte cultures and 3 organotypic cultures. We performed laser irradiation of test group with Wiser Doctor Smile Lambda, Flat Top Handpiece, at 50 J/cm2 of fluency with one application every 40 h for a total of 5 applications. Forty-eight h after the last laser application, we investigated the presence and amount of keratins 5 and 8 with citofluorymetric and western blotting analyses. Analyses showed an increase in keratin synthesis in test group cultures, showing a remarkable increase in production of keratin 8 in co-cultures test. Laser biostimulation can considerably enhance keratin synthesis when applied with high energy doses and repeated applications to keratinocytes-fibroblasts co-cultures.

Evidence that cells from experimental tumours can activate coagulation factor X.

The procoagulant activity of cells from some experimental tumours isolated in culture or in single-cell suspensions from ascitic fluid was investigated. Cells from Lewis lung carcinoma (primary and metastasis), Ehrlich carcinoma ascites and JW sarcoma ascites were able to shorten markedly the recalcification time of normal, Factor VIII- and Factor VII-deficient but not of Factor X-deficient human plasma. The same cells generated thrombin when mixed with a source of prothrombin and Factor X, absorbed bovine serum (as a source of Factor V), phospholipid and calcium chloride. Thrombin formation was not influenced by the presence of Factor VII. Cells from Sarcoma 180 ascites were completely inactive in both test systems. It is concluded that cells from some experimental tumours have the capacity to activate Coagulation Factor X directly. These findings suggest the existence of an alternative "cellular" pathway in the initiation of blood clotting distinct from both the intrinsic and extrinsic mechanisms.