No abstract available.
Rabbits*

No abstract available.
Rabbits*

No abstract available.
Rabbits*

No abstract available.
Rabbits*

No abstract available.
Rabbits*

While calcium phosphate ceramics meet some of the needs for bone replacement, they have some limitation of unresorbability and fibrous encapsulation without direct bone apposition during bone remodelling. To address these problem, we developed a new ceramic, calcium metaphosphate(CMP), and report herein the biologic response to CMP in subcutaneous tissue, muscle and bone. Porous CMP blocks were prepared by condensation of anhydrous Ca(H2PO4)2 to form non-crystalline Ca(PO3)2. Macroporous scaffolds were made using a polyurethane sponge method. CMP block possesses a macroporous structure with approximate pore size range of 0.3-1mm. CMP blocks were implanted in 8 mm sized calvarial defect, subcutaneous tissue and muscle of 6 Newzealand White rabbits and histologic observation were performed at 4 and 6 weeks later. CMP blocks in subcutaneous tissue and muscle were well adapted without any adverse tissue reaction and resorbed slowly and spontaneously. Histologic observation of calvarial defect at 4 and 6 weeks revealed that CMP matrix were mingled with and directly apposed to new bone without any intervention of fibrous connective tissue. CMP blocks didn't show any adverse tissue reaction and resorbed spontaneously also in calvarial defect. This result revealed that CMP had a high affinity for bone and was very biocompatible. From this preliminary result, it was suggested that CMP was a promising ceramic as a bone substitute and tissue engineering scaffold for bone formation.
Rabbits ; Animals

No abstract available.
Rabbits* ; Regeneration*

The Naka-Rushton equation, R=R(max) I(n)/(I(n)+K(n)), has been used to describe the luminance-response function of the scotopic electroretinogram. R(max) is the asymptotic value of the b-wave amplitude as a function of stimulus luminance, K is the intensity that produces a b-wave amplitude that is one-half R(max) and n is a dimensionless contant that controls the slope of the function and represents the degree of homogeneity of retinal sensitivity. These three parameters are often used in experimental laboratories, since it can show selective changes in each parameter. The present study describes and compares the parameters of Naka-Rushton equation obtained by using ganzfeld stimuli(R(max)=363+/-32 uv, n=0.86+/-0.06, log K=-2.39+/-0.19 log cd.sec/m2) and direct flash stimuli(R(max)=354+/-28 uv, n=0.80+/-0.06, log K=-2.26+/-0.15 log cd.sec/m2) in 20 eyes of the normal pigmented rabbits respectively. The n values were significantly increased by the ganzfeld light stimuli than by the direct flash stimuli(p<0.05).
Rabbits ; Retinaldehyde

Ten pigmented raqbits were dark adapted for 30 minutes previously and then exposed to room illumination of 200 lux for 10 seconds. In mesopic adaptation, the oscillatory potentials(OPs) were recorded. The coefficient of variation in the peak latency, time interval, summed amplitude, and amplitude of each individual OP wavelet were obtained. The peak latency showed the smallest coefficient of variation. The summed amplitude of the OPa and the time interval showed smaller coefficient of variation than amplitude of each individual OP component. Therefore the peak latency, summed amplitude, and time interval may be reliable factors to evaluate the OPs. The increase of the light stimulus did not affect the amplitude of O3. However, O1 and O2 tended to increase in amplitude and O4 to decrease as the intensity of light stimulus increased. These facts may suggest that each individual component of OP has different orign. As the intensity of light stimulus increased, the summed amplitude of OPs was increased and peak latency of O1, O2, O3, and O4 were decreased. Time intervals showed no significant changes.
Lighting ; Rabbits*

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