Porcine enamel matrix derivative enhances trabecular bone regeneration during wound healing of injured rat femur.

To elucidate the effects of enamel matrix derivative (EMD: Emdogain) on bone regeneration in rat femurs after drill-hole injury, defects in bone were filled with either EMD or its carrier, PGA, as control. On postoperative days 4 to 28, dissected femurs were examined by means of various morphological approaches. In both experimental groups, formation of trabecular bone, which was immunostained for bone sialoproteins (BSP), had occurred in the medullary cavities at cylindrical bone defects on Day 7 postoperatively. Cuboidal osteoblasts were clearly observed on these newly-formed BSP-positive bone trabeculae. On Days 7 and 14, many multinucleated giant cells, which strongly expressed cathepsin K, had appeared on these bone trabeculae, indicating active bone remodeling. In these bone trabeculae, Ca and P weight % and Ca/P ratio were similar to those of cortical bone, and there was no significant difference between the PGA- and EMD-applied groups. Bone volume fraction of newly-formed bone trabeculae on Day 7 postoperatively was significantly higher in the EMD-applied group than in the PGA-applied controls. Because of active bone remodeling and the marked decrease of bone volume, on Days 14 and 28 postoperatively, however, there was no longer a significant difference in trabecular bone volume fraction between the experimental groups. Our results suggest that EMD possesses an osteo-promotive effect on bone and medullary regeneration during wound healing of injured long bones.

[Stimulating conditions of cold air caloric test].

This study is to clarify the effects of stimulating conditions on caloric response evoked by cold air stimulation. The five parameters of caloric nystagmus (latency, maximum slow phase velocity [Max. spv], Max. spv arrival time, frequency and duration) were examined. The different stimulating air temperature(0 degree C, 5 degrees C, 10 degrees C, 15 degrees C, 20 degrees C), flow rate (3.0, 4.0, 5.0, 6.0 l/m) and period(30, 45, 60, 90 sec) were used to evoke caloric nystagmus in normal subjects. 1. Effect to temperature When the intensity of air irrigation temperature increased, Max. spv, frequency and duration also tended to increase. Out of the five parameters, the duration of caloric nystagmus was the most relevant to the intensity of irrigation temperature. 2. Effect of stimulating period When the period of caloric stimuli increased, the Max. spv and its duration also increased. But, when the stimulating period was 90 seconds, the slow phase velocity reached to the maximum responses 60 seconds after starting the stimulation. Therefore, it is not necessary to stimulate for more than 60 seconds. 3. Caloric response evoked by 60 sec, 5.0 l/m at 5 degrees C air irrigation showed the same response as the caloric nystagmus provoked by 20 ml of water at 20 degrees C for 20 sec.

Inhibitory effects of antiviral compounds on respiratory syncytial virus replication in vitro.

We examined the inhibitory effect of 20 antiviral compounds, including ribavirin, on the replication of respiratory syncytial virus in HeLa and HEp-2 cell cultures. Of the compounds studied, pyrazofurin and 3-deazaguanine emerged as more potent inhibitors of respiratory syncytial virus than ribavirin. Based on their inhibitory effect on the cytopathogenicity of respiratory syncytial virus in HeLa cells, the average 50% effective dose of pyrazofurin and 3-deazaguanine for eight strains was 0.07 and 1.65 micrograms/ml, respectively; that of ribavirin was 5.82 micrograms/ml. The cytotoxicity of these compounds for HeLa cells was examined by monitoring the incorporation of radiolabeled uridine into cellular RNA. The selectivity indexes of pyrazofurin and 3-deazaguanine exceeded that of ribavirin by 70- and 11-fold, respectively. Pyrazofurin, 3-deazaguanine, and ribavirin inhibited both viral antigen expression and syncytium formation in HeLa cell cultures, as assessed by an indirect immunofluorescence assay. In these assays, pyrazofurin and 3-deazaguanine again proved more potent than ribavirin. 2,5-Diamidinoindole and carbodine were less potent than ribavirin. Various other compounds, i.e., 3-adenin-9-yl-2-hydroxypropanoic acid isobutyl ester, 3-deazauridine, 3'-C-methyluridine, 5'-deoxy-5-fluorouridine, 5-cyanoimidazole-4-carboxamide, and its ribofuranosyl derivative, did not inhibit the cytopathic effect of the Long strain of respiratory syncytial virus at concentrations greater than or equal to 125 micrograms/ml. Tubercidin, 5-chlorotubercidin, xylotubercidin, neplanocin A, thiosemicarbazone R, and 3-methylquercetine were too toxic to HeLa cells for their inhibitory effects on respiratory syncytial virus to be examined.