No abstract available.
Rabbits*

No abstract available.
Rabbits*

No abstract available.
Rabbits*

No abstract available.
Rabbits*

No abstract available.
Rabbits*

To understand the mechanism of cell injury when exposed to HgCl2, monitoring of cytosolic ionized free Ca2+([Ca2+]i), viability test, measurement of the amount of ATP, and Ca-ATPase activity were evaluated in cultured rabbit renal tubular cells(RTC) exposed to HgCl2. The results were as follows: 1) HgCl2 was cytotoxic to rabbit RTC at all doses except 10 uM and the rate of killing displayed a dose- and time-dependent relationship. 2) The absence of extracellular Ca provided partial protection from irreversible injury induced by HgCl2. 3) The increasing pattem of [Ca2+]i varied according to the concentrations of HgCl2. At the low concentrations of HgCl2 (2.5-10 microM), the level of [Ca2+]i increased slowly over the flat 2-3 min and then achieved plateau-state. In contrast, at the high concentrations of HgCl2 (25-100 microM) the level of [Ca2+]i achieved peak within 1 min and then decreased to a plateau state under normal concentrations. 4) The level of ATP was decreased to 27.5% of that of normal control cells within 3 min by using a treatment of 100 microM HgCl2. 5) HgCl2 did not affect the Ca2+ ATPase activity by enzyme histochemical observation. These findings suggest that the elevation of [Ca2+]i in response to the HgCl2-induced injury is an important event in accelerating injury that ultimately leads to cell death. But other possibilities such as HgCl2 might have direct deleterious effects on the also should be considered.
Rabbits ; Animals

No abstract available.
Osteotomy* ; Rabbits*

No abstract available.
Osteotomy* ; Rabbits*

No abstract available.
Rabbits ; Animals

The procedure that enhances osteogenesis and shortens the healing period is required for successful implant therapy. It has been introduced that osteogenesis is enhanced by the generation of electric field. Many researchers have demonstrated that application of electric and electromagnetic field promote bone formation. It also has been shown that electrical stimulation enhances peri-implant bone formation. Recently, several investigators have reported that noninvasive electrical stimulation using negatively charged electret such as polytetrafluoroethylene(PTFE) promotes osteogenesis. Therefore, we were interested in the effect of noninvasive electrical stimulation using negatively charged electret on the periimplant bone healing. After titanium implant were installed in the proximal tibial metaphysis of New Zealand white rabbit, negatively charged PTFE membrane fabricated by corana dischage was inserted into the inner hole of the experimental implant and noncharged membrane was applied into control implant. After 4 weeks of healing, histomorphometric analysis was performed to evaluate peri-implant bone response. The histomorphometric evaluations demonstrated experimental implant tended to have higher values in the total bone-to-implant contact ratio(experimental ; 49.9+/-13.52% vs control ; 37.5+/-19.44%) , the marrow bone contact ratio(experimental ; 34.94+/- 13.32% vs control ; 24.15+/-13.69%), amount of newly formed bone in the endosteal region(experimental ; 1.00+/-0.30mm vs control ; 0.61+/-0.24mm) and bone area in the medullary canal(experimental ; 13.55+/-4.98% vs control ; 9.03+/-3.05%). The mean values of the amount of newly formed bone(endosteal region) and bone area(medullary canal) of the experimental implant demonstrated a statistically significant difference as compared to the control implant(p<0.05). In conclusion, noninvasive electrical stimulation using negatively charged electret effectively promoted peri-implant new bone formation in this study. This method is expected to be used as one of the useful electrical stimulation for enhancing bone healing response in the implant therapy
Rabbits ; Animals