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Biomedical subjects

J Laser

Publications and source records attributed to J Laser.

9 recordsLinked to original sources
PubMed2001

Treatment of ischemic wounds using cultured dermal fibroblasts transduced retrovirally with PDGF-B and VEGF121 genes.

The healing of ischemic wounds is a particularly difficult clinical challenge. In this study, rabbit dermal fibroblasts transduced retrovirally with human platelet-derived growth factor B (PDGF-B) and human vascular endothelial growth factor 121 (VEGF121) genes were used to treat wounds in a rabbit ischemic ear model. The PDGF-B and VEGF121 genes were obtained from human umbilical vein endothelial cells (HUVECs) by reverse transcription-polymerase chain reaction, cloned into retroviral vectors under control of the beta-actin promoter, and introduced into primary rabbit dermal fibroblast cells. In vitro results demonstrated that rabbit dermal fibroblasts are transduced and selected readily using retroviral vectors, and are engineered to secrete PDGF-B and VEGF121 at steady-state levels of 150 ng per 10(6) cells per 24 hours and 230 ng per 10(6) cells per 24 hours respectively. These cells were then seeded onto polyglycolic acid (PGA) scaffold matrices and used to treat ischemic rabbit ear wounds. Immunohistochemistry showed intense staining for PDGF-B and VEGF121 in the wounds treated with these transduced cells compared with the control treatment groups. For the relatively more ischemic distal ear wounds, granulation tissue deposition was increased significantly in the wounds treated with PDGF-B- and VEGF121-transduced cells compared with wounds treated with PGA alone. These results demonstrate that gene augmentation of rabbit dermal fibroblasts with the PDGF-B and VEGF121 genes introduced into this ischemic wound model via PGA matrices modulates wound healing, and may have clinical potential in the treatment of ischemic wounds.

Animals↗
PubMed1999

Cartilage tissue engineering: current limitations and solutions.

Articular cartilage repair remains one of the most intensely studied orthopaedic topics. To date the field of tissue engineering has ushered in new methodologies for the treatment of cartilage defects. The authors' 10-year experience using principles of tissue engineering applied to resurfacing of cartilage defects is reported. Which cell type to use, chondrocytes versus chondroprogenitor cells, and their inherent advantages and disadvantages are discussed. Chondrocytes initially were used as the preferred cell type but were shown to have long term disadvantages in models used by the authors. Mesenchymal stem cells can be used effectively to overcome the limitations experienced with the use of differentiated chondrocytes. The use of mesenchymal stem cells as platforms for retroviral transduction of genes useful in cartilage repair introduces the concept of gene modified tissue engineering. The fundamental conditions for promoting and conducting a viable cartilage repair tissue, regardless of which cell type is used, also were studied. Placement of a synthetic porous biodegradable polymer scaffold was found to be a requirement for achieving an organized repair capable of functionally resurfacing a cartilage defect. A new modular device for intraarticular fixation of various graft composites has been developed. This new cartilage repair device is composed of bioabsorbable polymers and is capable of being delivered by the arthroscope.

Animals↗
PubMed1993

Altered expression of the retinoblastoma susceptibility gene in chronic lymphocytic leukaemia.

The pathogenesis of chronic lymphocytic leukaemia (CLL) is unknown. One of the most frequent cytogenetic abnormalities in CLL is a deletion within the long arm of chromosome 13, the region to which the retinoblastoma (Rb) gene has been mapped. Lack of Rb expression has been linked to the carcinogenic process in many human tumours. We therefore sought to investigate the role of Rb gene inactivation in CLL using differential polymerase chain reaction on reverse transcribed RNA. The result of the PCR was quantitated using HPLC. 5/39 patients revealed a lack or significantly impaired expression of the Rb gene upon differential PCR analysis. In addition, immunocytochemical studies were performed using the Rb-specific monoclonal antibody PMG245. 10/56 patients showed a weak or absent expression upon immunocytochemical analysis compared to monocytes or granulocytes. The samples lacking Rb were from both early and late stage CLL. Our results indicate that inactivation of the Rb protein occurs in a fraction of CLL cases and can be found in early and late stages of the disease.

Aged↗
PubMed1988

Evidence of cross-reactivity of 'carcinoma-specific' KC4 monoclonal antibody with activated mesothelial cells and phytohemagglutinin-stimulated lymphocytes.

Carcinoma-specific antibodies would be a useful tool in immunocytology of serous effusions. We tested the carcinoma-'specific' monoclonal antibody KC4 with cells obtained from pleural effusions evaluated by thoracoscopy and pleural biopsies. KC4 reacted most strongly with carcinoma cells. However, activated mesothelial cells also expressed this marker strongly. Lymphocytes stimulated with phytohemagglutinin were also stained by KC4. Thus KC4 appears to detect a proliferation antigen rather than a carcinoma-specific antigen.

Antibodies, Monoclonal↗
PubMed1987

[Effect of repeated leukaphereses on the lymphocytogram of blood donors].

Donors risk lymphopenia as a result of thrombocytapheresis as well as leukapheresis. The importance of the removal of lymphocytes is speculative at present. In the study presented, 10 healthy blood donors underwent 5 consecutive, discontinuous flow-leukapheresis procedures in weekly intervals with the effect of a total loss of 2.6 X 10(10) lymphocytes. The number of peripheral lymphocytes decreased steadily from 1,850 +/- 417/microliter to 1,451 +/- 411/microliter over the 5-week period. A significant decrease comprised also OKT3+-, OKT4+- and B-lymphocytes but not OKT8+-cells. Accordingly the OKT4/OKT8 ratio was reduced though not significantly from 1.41 +/- 0.25 to 1.32 +/- 0.27. 6 months after the last apheresis, the total lymphocyte count, OKT3+- and B-lymphocytes were still significantly low. The long-lasting peripheral lymphopenia in cytapheresis donors has to be taken into account as one of the criteria for donor selection. Donors with less than 1,000 lymphocytes/microliter of peripheral blood should be excluded from cytapheresis procedures.

Blood Donors↗