No abstract available.
Rabbits*

No abstract available.
Rabbits*

No abstract available.
Rabbits*

No abstract available.
Rabbits*

No abstract available.
Rabbits*

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

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

No abstract available.
Rabbits ; Animals

PURPOSE: The aim of this study was to evaluate the effectiveness and indication of radiofrequency ablation(RFA) using renal VX2 tumors by implantation of VX2 tumor cells under the renal capsule in rabbits. MATERIALS AND METHODS: Ten rabbits were injected with 30-40microliter VX2 tumor cells(1.2x10(7) viable cells/ml) under the renal capsule of the right kidney by right subcostal incision. On the 14th day after the tumor cells were implanted, we checked for the development of renal tumors, and the sizes and shapes(exophytic or central) of the tumors by the use of computed tomography. We performed RFA in the renal VX2 tumors with a 17G StarBurst electrode through kidney exposure. After the first and third day following RFA, renal function was checked. On the third day, we performed CT and harvested the kidneys for gross and microscopic evaluation. RESULTS: We confirmed the development of renal VX2 tumors in nine cases. Tumor shapes were exophytic in seven cases and central in two cases; the mean size of the tumors was 2.1 cm(range, 1.1-3.8cm). In all tumors, RFA was performed. From the use of enhanced CT after RFA on the third day, all of the lesions treated with RFA showed no enhancement. From the pathological findings, coagulative necroses were seen on all of the lesions treated with RFA. The necrotized tumor size after RFA was not different statistically as measured by CT and a pathological examination (p=0.833) CONCLUSIONS:: In centrally located renal tumors, we experienced thermal injury in pelvocalyceal systems. RFA is an effective method for nephron sparing surgery as the tumor cells completely disappear and there is preserved renal function and the procedure is easy to apply. We suggest that the RFA method for exophytic renal tumors is more effective than other procedures.
Rabbits ; Animals

Ketamine hydrochloride(ketamine) is a non-barbiturate anesthetic agent chemically designated as dl-2-(0-chlorophenyl)2-(methylamino)-cyclohexanone hydrochloride. Ketamine anesthesia has been found distinctively different from that induced by conventional anesthetic agents, as it provides profound analgesia without significant impairment of respiratory function or stimulation of cardiovascular activities thus avoiding hypotension and are preserved the protective pharyngeal and laryngeal reflexes. In addition, ketamine appears to have muscle relaxation properties. This latter clinical finding, however has not been experimentally substantiated since few reports have appeared on the effect of ketamine on muscle relaxation. The present study therefore, was undertaken to determine whether this agent affects the muscle activity during d-tubocurarine block. The experiment was performed on sixteen rabbits weighing 1.8 to 2.5kg and these were divided into two groups; eight rabbits for control and eight for th study group. All animals were intubated through a tracheostomy under general anesthesia with nembutal 40mg/kg given intravenously. Respiration was controlled by means of a Harvard animal respirator. The body temperature was kept at 35 degrees C to 36 degrees C with a thermo-blanket. The common peroneal nerve and anterior tibial muscle was exposed and the nerve stimulator was applied to the nerve muscle preparation. The twhitch height of the muscle contraction was recorded on a biophysiograph through the force displacement transducer. The common peroneal nerve was stimulated supramaximally using a single twitch, square wave of 0.2 msec duration at a frequency of 0.1Hz once every 10 seconds. The degree of neuromuscular block following intravenous injection of d-tubocurarine 1mg/kg was measured in the control group. And in the study group ketamine 5mg/kg was administered intravenously when 25% of twitch height of muscle contraction was obtained spontaneously after the intravenous injection of d-tubocurarine 1mg/kg. The changes of the twitch height of muscle contraction and the time of spontaneous recovery in the study group were compared with those of the control group. The results were as follows: 1) The times and degree of maximal single twitch depression were obtained at 194.8sec and 87.3% in the control group and were at 197.5 sec and 87.8% in study group. No significant difference was observed. 2) Recovery index of the control group was 1,560.0 sec and recovery index of the study group was markedly prolonged to 2,387.5 sec(53.0% prolongation). 3) Mean decrease of single twitch height was 8.8% soon after the intravenous ketamine 5mg/kg when 25% of twitch height was obtained after the intravenous d-tubocurarine 1mg/kg in the study group.
Rabbits ; Animals