Three fresh kidneys removed from three adult bodies were perfused through the renal artery with 5％ and 10％ ABS (a copolymer of allylcyanide, butadiene and styrolene). Small specimens removed from the kidney were digested in 50％ HCI. Cast replicas of renal arteries and their branches were taken and examined with SEM (S-450 or S-520). The results were as follows.The capillary network of the area of the polar cushion cell were observed at the hilum of glomerulus in our casts. Their appearances are triangular, tetragonal or comma-like. In general, the shape of the meshes of the capillary network was round, oval, triangular or tetragonal. The diameters of the meshes were smaller than that of the vessels themselves. The microvessels of the area of the polar cushion cell, which mainly originated from the afferent arteriole, were continuous with the capillary of the glomerulus. The afferent arteriole was often traveled in the central part of the area of the polar cushion cell. The function of the microvessels of the area of the polar cushion cell was discussed in this article.

Two fresh kidneys removed from two male adult bodies, about 48 hrs. after death, were injected through the renal artery with ABS (a copolymer of allyl cyanide, butadiene and styrolene) at a constant pressure between 250-280 mmHg. Corrosion casts were prepared for the study of glomerular vasculature. Small specimens were cut out from the kidney were digested in 20% HCl and 10% peptic solution. Cast replicas of renal arteries and their branches were removed and examined with the SEM (Hitachi H-500 with Scanning accessories HSE_2). The chief results of observation were as follows: The corrosion-cast models of adults' glomerular vessels observed under the SEM consisted of two kinds: the spherical glomerulus and the chrythsanthemum-like glomerulus. The system of capillary loops of the spherical glomerulus was interconnected by anastomosed vessels. The lobular patterns of the glomerular capillary loops as described in the mouse kidney by Hall were not observed. The chrythsanthemum-like glomerulus consisted of many branches of capillaries, either longer or shorter, and most ended blindly. No more than one efferent or afferent vessel have been observed in our corrosioncast specimen of the adults' glomerular vessels. In general, the afferent and efferent arteriole enters or exits at the hilum of glomerulus. Rarely, the efferent vessel left the glomerulus at the oppositeside of the hilum. By-pass tract between the afferent and efferent vessels was not found in our casts. Constrictions of the afferent arterioles such as those shown in rats by Shonyo and Mann ('44) were not demonstrated in the adults' kidneys. Sometimes, there is a constriction near the point of origin of the afferent arteriole.

We have previously demonstrated the expression of GATA-DNA-binding protein (GATA)-3, a transcription factor, in osteoblasts and have verified its function in transducing cell survival signaling. This translational study was further designed to evaluate the roles of GATA-3 in regulating bone healing and to explore its possible mechanisms. A metaphyseal bone defect was created in the left femurs of male ICR mice. Analysis by micro-computed topography showed that the bone volume, trabecular bone number and trabecular thickness were augmented and that the trabecular pattern factor decreased. Interestingly, immunohistological analyses showed specific expression of GATA-3 in the defect area. In addition, colocalized expression of GATA-3 and alkaline phosphatase was observed at the wound site. As the fracture healed, the amounts of phosphorylated and non-phosphorylated GATA-3 concurrently increased. Separately, GATA-3 mRNA was induced during bone healing, and, levels of Runx2 mRNA and protein were also increased. The results of confocal microscopy and co-immunoprecipitation showed an association between nuclear GATA-3 and Runx2 in the area of insult. In parallel with fracture healing, Bcl-XL mRNA was significantly triggered. A bioinformatic search revealed the existence of a GATA-3-specific DNA-binding element in the promoter region of the bcl-x(L) gene. Analysis by chromatin immunoprecipitation assays further demonstrated transactivation activity by which GATA-3 regulated bcl-x(L) gene expression. Therefore, this study shows that GATA-3 participates in the healing of bone fractures via regulating bcl-xL gene expression, owing to its association with Runx2. In the clinic, GATA-3 may be used as a biomarker for diagnoses/prognoses or as a therapeutic target for bone diseases, such as bone fractures.
Alkaline Phosphatase ; Animals ; Bone Diseases ; Cell Survival ; Chromatin Immunoprecipitation ; Computational Biology ; Femur ; Fracture Healing ; Fractures, Bone ; Gene Expression ; Humans ; Immunoprecipitation ; Male ; Mice ; Mice, Inbred ICR ; Microscopy, Confocal ; Osteoblasts ; Promoter Regions, Genetic ; RNA, Messenger ; Transcription Factors ; Transcriptional Activation ; Up-Regulation* ; Wounds and Injuries