Masaharu Takigawa

Peripheral type benzodiazepine receptor in T lymphocyte rich preparation.

Some types of mood disorders and drugs are suggested to affect peripheral type benzodiazepine receptors (PBR), but their mechanisms are unclear. The isolation of pure lymphocytes is requisite for the investigation of the function of PBR on lymphocytes, since platelets and monocytes also have many PBR. The objective of this study was to establish a method of binding assay for PBR using pure T lymphocytes. Mononuclear cells and T lymphocytes were prepared by using a density gradient material and magnetic beads, respectively. The cells were analyzed using flow cytometry and a counting chamber. Binding studies were performed using T lymphocytes from 10 normal volunteers. The T lymphocytes were incubated with [3H]PK11195, harvested on glass fiber filters, and counted with a plate scintillation counter. The binding data were analyzed by the Scatchard method. With the magnetic bead technique, pure T cells were selected that contained only 1.5% monocytes and platelet/cell ratio of 1.4. The Scatchard plot of the data indicated that only one type of specific binding site was involved in the binding. The dissociation constant (Kd) was 3.8+/-1.3nM (mean+/-SD), and the Bmax was 379+/-124 fmol//10(6) cells (mean+/-SD). The density gradient- magnetic beads technique can be used as an appropriate method of preparation of T cells for PBR binding assay.

Cartilaginous differentiation in the joint capsule.

Abstract: The proliferation and differentiation of cells are greatly influenced by their environment. Many growth factors and cytokines are reported to be environmental factors that affect the proliferation and differentiation of cells. Mechanical stress is also considered to influence these physiological reactions. The joint capsule, which is a part of the joint tissue, plays a very important role in the stability of the joint and in maintaining the intracapsular phenomenon. In patients with dislocated hip arthropathy, this capsule is involved in the weightbearing function by forming a sliding surface between the capsule and the femoral head articular cartilage. The surface of the tissue macroscopically shows cartilaginous change, which indicates cartilaginous differentiation caused by mechanical stress. We examined the cartilage-specific proteoglycan component, which is composed of cartilaginou matrix at the differentiation site. We investigated proteoglycan production, molecular size, and the gene expression of cartilaginous substrate. At the inner layer of the weightbearing area of the joint capsule, proteoglycan production was significantly higher than that of other noncartilaginous tissue. We also identified the gene expression of cartilaginous proteoglycan using the reverse transcription polymerase chain reaction (RT-PCR) method.