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Prostaglandin F(2alpha) (PGF(2alpha)) is implicated in the process of luteal regression in many species. Treatment of rat luteal tissue with PGF(2alpha) increases the generation of reactive oxygen species. Since reactive oxygen species have been implicated in apoptosis, the present study was undertaken to determine whether reactive oxygen species play a role in the PGF(2alpha)-induced apoptosis of rat luteal cells. Rat luteal cells were loaded with 6-carboxy-2, 7'-dichlorodihydro-fluorescein (CDCFH) diacetate, di (acetomethyl ester), which can be oxidized by reactive oxygen species to yield CDCF, a fluorescent molecule, and the cells were treated with different doses of PGF(2alpha). Incubation with 100 micromol PGF(2alpha) l(-1) induced an increase in CDCF fluorescence (P < 0. 05). Treatment of cells with PGF(2alpha) for 48 h in serum-free medium induced a dose-dependent increase in cell death, and these cells exhibited the morphological characteristics typical of apoptosis, including condensed or fragmented nuclei and fragmentation of internucleosomal DNA. Pretreatment of these cells with ascorbic acid, N,N'-dimethylthiourea, or superoxide dismutase, which acts as an antioxidant or a radical scavenger, prevented the PGF(2alpha)-induced apoptosis. These results demonstrate that PGF(2alpha) produces reactive oxygen species and induces apoptosis in rat luteal cells, indicating that the reactive oxygen species may induce apoptotic cell death during luteolysis.

The flow around a circular cylinder placed close to a horizontal plane wall was investigated experimentally. Fluctuations of lift and drag of the cylinder and wall interference effects were studied in terms of the gap height between the cylinder and wall and the thickness of the turbulent wall boundary layer. The fluctuating fluid forces acting on the cylinder sharply increased, and the regular vortex shedding, i.e. Kárman vortex streets, started to form beyond a critical gap height. The formation of Kárman vortex streets was abruptly interrupted when the bottom of the cylinder came in contact with the outer layer of the boundary layer developed on the wall. This critical gap height correlated well with the thickness of the boundary layer.

Transcatheter chemo-embolization (TCE) in hepatocellular carcinoma (HCC) was performed in 38 patients. The patients were examined by MR imaging before TCE as well as one week and 4 to 5 weeks after TCE. The tumor signal intensity in T2 weighted images increased in 13 cases and decreased in 19 cases after TCE. Increased intensity seemed to reflect intra-tumoral hemorrhage or liquefaction accompanying tumor necrosis. Decreased intensity seemed to reflect coagulation necrosis. In 9 of 18 cases followed over a 2-month period the signal intensity had decreased in both T1 and T2 weighted images. In these patients the tumor showed no recurrence at angiography and the decreased signal seemed to reflect the completion of coagulation necrosis. A hyper- and/or hypointense rim around the tumor appeared in 22 cases. These changes were thought to be perifocal edema or granulation tissue around the tumor. MR imaging was useful in evaluating the necrotic process of the tumor after TCE.

We used power Doppler imaging to examine neovascularization in the corpus luteum (CL) in 12 healthy volunteers. We also investigated whether CL blood flow reflected luteal function. The ratio of the area of vessels in the CL to the area of a sectional plane at the maximum diameter of the CL observed by power Doppler (FA ratio) was used as a quantitative index of the vascularity of the CL. The pulsatility index (PI) was significantly lower in ovarian arteries with CL than without CL (P < 0.05). Changes in ovarian arterial and intra-luteal PI appeared to reflect physiological changes in the vasculature of the CL. There was no correlation between the volume of the CL or the FA ratio and the concentration of progesterone. The pattern of changes in the product of the FA ratio and the CL volume and in the progesterone concentration was similar. The progesterone concentration was positively correlated with this product (r = 0.74, P < 0.01). The product of the FA ratio and the CL volume plateaued during the mid- to late luteal phase, suggesting the presence of functional and structural luteolysis. These findings suggest that colour Doppler ultrasonography, including power Doppler imaging, can detect physiological changes in the blood flow of the ovary in the luteal phase, and may be a useful non-invasive tool for evaluating CL function.Keywords:blood flow/corpus luteum/power Doppler/vascularity

Transcatheter chemo-embolization (TCE) in hepatocellular carcinoma (HCC) was performed in 38 patients. The patients were examined by MR imaging before TCE as well as one week and 4 to 5 weeks after TCE. The tumor signal intensity in T2 weighted images increased in 13 cases and decreased in 19 cases after TCE. Increased intensity seemed to reflect intra-tumoral hemorrhage or liquefaction accompanying tumor necrosis. Decreased intensity seemed to reflect coagulation necrosis. In 9 of 18 cases followed over a 2-month period the signal intensity had decreased in both T1 and T2 weighted images. In these patients the tumor showed no recurrence at angiography and the decreased signal seemed to reflect the completion of coagulation necrosis. A hyper- andor hypointense rim around the tumor appeared in 22 cases. These changes were thought to be perifocal edema or granulation tissue around the tumor. MR imaging was useful in evaluating the necrotic process of the tumor after TCE.