Stem cell renewal and contraction of the tunica media caused by a damaged blood vessel following a thick needle stab.

A marked difference in the healing process of the inferior vena cava in rats following a stab with a 17-G (1.48 mm phi) ultrahard zirconium ceramic (Zr) needle and with a common stainless steel (St) needle (also 1.48 mm phi was observed. This was investigated in vivo by histological imaging and biochemical micro-autoradiographic imaging using [2-(14)C]-thymidine as a biomarker in vivo. On the first day after the stab with either, the Zr or the St injection needle, the tunica adventitia showed the most pronounced damage, as evidenced by a large puncture wound characterized by blood congestion, but with few inflammatory cells being observed. A marked contraction of the tunica media was observed. The depth of the injury reached the tunica layer, but amounted to less than 1/3 of the needle diameter. Loose fragments of the endothelial lining were detected, together with scattered red corpuscles. The survival rate of the experimental animals amounted to less than 40% on the 3rd day after the stab by either the Zr or St needle, due to the large needle diameter. In addition, histological imaging of the wound area in the endothelial layer and tunica media showed considerable congestion and inflammation, which limited the evaluation of the regeneration status of the inferior vena cava of the surviving animals. Results were obtained from a few animals that displayed satisfactory recovery status. On the 3rd day after the stab by either the Zr or St injection needle, a relatively large proportion of the hemostatic clots became incorporated into the collagenous tissue, i.e. the tunica adventitia. A marked contraction of the tunica media was also observed, similar to that on the 1st day, following the needle injury. In the case of the endothelium (tunica intima), the injury caused by the Zr needle was reinfiltrated by adult stem cells 3 days after the stab, but the tunica media, composed of endothelial cells, still contained relatively contracted collagenous material. In addition, several interesting cell colonies were observed in the medial layer at the short distance from the boundary of the damaged tissue. It was assumed that these colonies produced medial tissue composed of collagenous supporting tissue or smooth muscle cells. In the experiment using the St needle, the incorporation of [2-(14)C]-thymidine into the nucleus of the stem cells was observed in the small capillaries of the tunica media, but not in the support cells of the latter.

[2-14C]Thymidine incorporation activity of stem cells in either tumor or cradle tissues in a normal or transplanted animals.

A novel autoradiographic procedure was developed for such continuously cycling cells as stem cells on account of proliferating rate of which is astronomically high per min. Negative visualization is observed over any mitotic image by use of a biomarker, "[2-14C]thymidine" for a few minutes in both cases, either in vivo or in vitro systems. But, good visualization images were realized by many 14C-beta tracks over stem cells with a few minute labelling of [2-14C]thymidine in originated cradles as predicted by Burkitt, H.G(1993). It is clearly elucidated that a short and quick labelling procedure of [2-14C]thymidine is useful to evaluate toxicity and efficacy of new drug candidates and to diagnose cluster of unknown malignity or proliferation rate of respective stem cell in in vivo or Ex-vivo system. Results show that the cell proliferation rate of the stem cells in respective tissues was markedly suppressed, dependent on time after dosing and the dose of 90Y; 3.7, 37, 370, 3,700, and 37,000 kBq per mouse (25g). In addition to the above, the sensitivity of the proliferation rate was dependent on amitosis or mitosis and the AUC value of 90Y-concentration at specific locations of the cells in the mouse body. The most sensitive cells were the plasmacytoma cells, followed by the pluripotent and unipotent stem cells, the intestinal crypts, epiphysial growth plate and liver cells. Results in this presentation, also gives a clear evidence showing a revival of facultative divider line from G0 stage of epithelium and mascular meditate into the unipotent stem cell cycle. Application of [2-14C]thymidine is useful for evaluation of a grade of maturation in differentiation of malignant cells or replicable unipotent stem cells.

Synchronous evaluation of toxico- and pharmaco-dynamics of yttrium-90 by a novel autoradiographic procedure.

A synchronous evaluation was performed, using a quick in vivo [2-(14)C]thymidine labeling method, of the toxico- and pharmaco-dynamics of a given dose of yttrium-90 (90Y) at a given time after injection to nude BALB/c mice loaded with 10(7) HuO9 cells. Quantitative data were 14C-microautoradiographs of the liver lobule, intestinal crypts, epiphysial growth plate, secondary ossification center containing pluripotent stem cells, perifollicular zone containing unipotent stem cells in the spleen, and plasmacytoma cells in the osteogenic sarcoma in each mouse following a 10-min labeling with 14C at 0.5, 6, and 24 h after i.v. injection of 90Y. Results show that the cell proliferation rate of the stem cells in respective tissues was markedly suppressed, dependent on time after dosing and the dose of 90Y; 3.7, 37, 370, 3700, and 37,000 kBq per mouse (25 g). In addition to the above, the sensitivity of the proliferation rate was dependent on amitosis or mitosis and the AUC value of 90Y-concentration at specific locations of the cells in the mouse body. The most sensitive cells were the plasmacytoma cells, followed by the pluripotent and unipotent stem cells, the intestinal crypts, epiphysial growth plate, and liver cells.