Crystallization process of transparent conductive oxides Zn(k)In2O(k+3).

Crystallization process of the homologous compounds Zn(k)In2O(k+3) from the coprecipitants was examined by XAFS spectroscopy and X ray diffractometry. Interesting crystallization behavior could be observed. Though zinc oxide already crystallized as the wurtzite-type ZnO at 573K, indium oxide remained amorphous. Subsequently bixbyite-type In2O3 appeared at 873K for k=5 and 7 and at below 773K for the other k-members, respectively. The InO distance in the amorphous In2O3 was a little shorted than that in the bixbyite-type In2O3 by 0.06-7A. The distance remained constant but abruptly increased to that observed in the bixbyite-type In2O3 in accordance with the progress of crystallization. Then the distance gradually decreased and converged to ca. 2.12A at the temperature range of 1173-1373K, due to the reaction between In2O3 and ZnO to form the homologous compound.

Protection by vascular endothelial growth factor against sinusoidal endothelial damage and apoptosis induced by cold preservation.

BACKGROUND: It is well known that sinusoidal endothelial cell (SEC) damage during cold preservation of liver tissue is closely involved in early graft failure. The objective of this study was to investigate the involvement of apoptosis in the SEC damage induced by cold preservation and to demonstrate the protective effect of vascular endothelial growth factor (VEGF) on SEC injury, including apoptotic changes. METHODS: Isolated SECs and liver tissue of Wistar rats were cold-preserved in University of Wisconsin (UW) solution, and the protective effect of VEGF was then investigated. Isolated SECs were cultured for 24 hr, and divided into the following 3 groups: Group A, in which the cells were cultured for an additional 27 hr, Group B, in which the cells were cold-preserved in UW solution for 3 hr, and then recultured for 24 hr, and Group C, in which 20 ng/ml of VEGF was added to both the culture medium and the UW solution of cells cultured according to the Group B protocol. Each group of SECs was morphologically examined using the phase contrast microscopic method and the transmission electron microscopic method (TEM), and quantitatively analyzed using the WST-1 assay. Rat livers were cold-preserved in UW solution and divided into the VEGF(+) group and the VEGF(-) group, depending on whether VEGF was added or not. Each group of livers were analyzed by scanning electron microscopic method (SEM) after 24 hr of preservation. The hyaluronic acid uptake rate (HUR) was also determined after 6 hr of preservation. After 24 hr of preservation and 6 hr of reperfusion, tissues were examined by TEM and by the terminal deoxynucleotidyl transferase d-uridine triphosphate nick end labeling (TUNEL) assay. RESULTS: The phase contrast microscopic method and the WST-1 assay showed a protective effect of VEGF against the injury to isolated SECs during cold preservation and subsequent reculturing. Apoptosis was detected immediately by TEM after isolation of SECs, and the number of apoptotic cells increased with the incubation time. This increase was accelerated after cold preservation. The scanning electron microscopic method and the hyaluronic acid uptake rate showed a protective effect of VEGF against SEC damage in the cold-preserved livers. In the liver tissue, the TEM and the TUNEL assay detected apoptosis of SECs only after cold preservation and subsequent reperfusion. VEGF suppressed the apoptosis of SECs induced by cold preservation in both isolated cells and liver tissue. CONCLUSIONS: We demonstrated that SEC damage in the cold preservation of liver tissue was caused mainly by apoptosis, which required subsequent reperfusion. Moreover, isolated SECs showed spontaneous occurrence of apoptotic changes during culture, and these changes were accelerated by the preceding cold preservation. This is the first report to demonstrate the apoptotic changes of SECs seen here were inhibited by VEGF.

Morphologic alteration of hepatocytes and sinusoidal endothelial cells in rat fatty liver during cold preservation and the protective effect of hepatocyte growth factor.

BACKGROUND: Fatty liver grafts are considered to be one of the main factors of primary nonfunctioning graft in transplantation. We investigated here, the hepatic damage during cold preservation in a rat fatty liver model by ultrastructural observation, and examined the effect of human recombinant hepatocyte growth factor (hrHGF) on amelioration of the cold-preserved graft condition. METHODS: Wistar rats were fed a choline-deficient diet (CDD) for 7 days. Livers were stored in cold University of Wisconsin (UW) solution for 0, 4, and 24 hr. We evaluated the ultrastructural alteration of the hepatocytes, sinusoidal architecture, and endothelial cells (SECs) by scanning and transmission electron microscopy. Ex vivo, we measured alanine aminotransferase (ALT) in first effluent as an index of hepatocyte injury and the hyaluronic uptake rate (HUR) as that of SEC damage. We injected hrHGF into rats fed CDD for 7 days through the portal vein and also added it to the UW solution to determine whether or not the agent ameliorated the hepatic damage in cold-preserved fatty livers. RESULTS: In rats fed CDD for 7 days, the lesion occupied by fat deposits appeared to enlarge with the duration of cold preservation leading to the disarrangement of sinusoidal architecture. Furthermore, sinusoidal endothelial damage, in which gaps, blebs, microvilli, and sinusoid denudation were detected, appeared to be more severe in these livers than in the corresponding control livers. ALT significantly increased in the 4-hr cold-preserved livers of rats fed CDD for 7 days. HUR decreased with 4-hr cold preservation and/or with CDD feeding. Administration of hrHGF prevented the expansion of fatty droplets and reduced SEC injury as detected by morphological observations. Increase of ALT in first effluent was inhibited to about one fourth the level observed in the 4-hr cold-preserved livers of rats fed CDD. Moreover, HUR significantly increased with the pretreatment of hrHGF. CONCLUSION: The hepatic injury in both hepatocytes and SECs in cold-preserved fatty liver graft developed more rapidly and severely than in the corresponding controls and demonstrated a protective effect of hrHGF.

Vascular endothelial growth factor-induced tumor angiogenesis and tumorigenicity in relation to metastasis in a HT1080 human fibrosarcoma cell model.

Although vascular endothelial growth factor (VEGF) is well known to be a potent mitogen for vascular endothelial cells, the role of VEGF in a developmental process of tumor angiogenesis and metastatic potential remains poorly understood. The present study was designed to investigate VEGF-induced vascular formation from a spatiotemporal viewpoint and to analyze VEGF-enhanced metastatic potential using stable clones of HT1080 human fibrosarcoma cells transfected with VEGF cDNA (S) or with vector alone (V). Microangiography revealed massive angiogenesis in the S cell-derived tumors and demonstrated that the angiogenesis occurred not in the tumor itself, but rather around the S cell tumor early after inoculation into the thigh muscles of mice. Thereafter, the angiogenesis extended in and around the tumor. The tumorigenicity of the S cells was higher than the V cells in the subcutaneous (s.c.) space, intraperitoneal space, liver and spleen. However, neither S cells nor V cells metastasized to the liver after an intrasplenic injection. Few apoptotic cells were detected in the S cell tumor, but many apoptotic cells were scattered in the V cell tumor. Our results indicate that VEGF facilitates tumorigenicity in various organs, possibly due to inducing angiogenesis in and around the tumor and preventing tumor cells from undergoing apoptosis, and suggest that VEGF may augment metastatic potential, by accelerating proliferative activity after reaching the target organ. Furthermore, VEGF-induced angiogenesis occurred preferentially around the tumor at an early period of tumor development, followed by neovascularization into the tumor.