Glial growth factors, proteins that are mitogenic for Schwann cells, and several ligands for the p185erbB2 receptor, are products of the same gene. Alternative splicing of the messenger RNA generates an array of putative membrane-attached, intracellular and secreted signalling proteins, at least some of which are expressed in the developing spinal cord and brain. These factors are probably important in the development and regeneration of the nervous system.
A major purpose of this study was to examine inhibitory effect of the catechin derivatives from Japanese green tea Camellia sinensis on collagenase activity. The crude tea catechins, which contain (+)‐catechin (C), (−)‐epicatechin (EC), (+)‐gallocatechin (GC), (−)‐epigallocatechin (EGC), (−)‐epicatechin gallate (ECg), and (−)‐epigallocatechin gallate (EGCg), were tested for their ability to inhibit the prokaryotic and eukaryotic cell derived collagenase activities. Among the tea catechins tested, ECg and EGCg showed the most potent inhibitory effect on collagenase activity when an optimal concentration of tea catechins (100 μg/ml) was added to reaction mixture containing collagenase and collagen. Preincubation of collagenase with tea catechins reduced the collagenase activity as well. In contrast to ECg and EGCg, the other four tea catechins (C, EC, EGC, and GC) did not show any collagenase inhibitory effect. Our results suggest that the steric structure of 3‐galloyl radical is important for the inhibition of collagenase activity. The collagenase activity in the gingival crevicular fluid from highly progressive adult periodontitis was completely inhibited by the addition of tea catechins. These results demonstrated that tea catechins containing galloyl radical possess the ability to inhibit both eukaryotic and prokaryotic cell derived collagenase. J Periodontol 1993; 64:630–636.
In this study, we applied cognitive behavioural intervention to subjects who had painful limited mouth opening, with or without posture correction in daily life. The efficacy of non-intervention control was then compared with it in order to study the effectiveness of posture correction as part of a biobehavioural therapy. The visual analogue scale (VAS) value of pain intensity at maximum mouth opening and disturbance in daily life sharply declined in the group which received only cognitive behavioural intervention and those who received it together with posture correction in daily life compared to the non-intervention control group although there was little difference between the intervention groups. Moreover, pain-free unassisted mouth opening was restored earlier in the group which had added posture correction. This suggests that posture correction in daily life has a positive effect in alleviating myofascial pain with limited mouth opening.
There have been many reports on fatal distortion of heat-activated acrylic denture-base resin which is still widely used in the field of removable prosthodontics. However, these reports have failed to report quantitatively on polymerization and thermal shrinkage factors. In the present study, we attempted to verify that the shrinkage of heat-activated acrylic denture-base resin was caused mainly by thermal contraction after processing. Furthermore, we examined the degree of distortion resulting from long, low-temperature processing, and compared the results with that of the conventional method. The strain gauge and thermo-couple were embedded in a specimen at the time of resin packing. The measurement started from the beginning of processing and continued until the specimen was bench-cooled and immediately before and after it was de-flasked, as well as during seven-day immersion in water at 37 degrees C. The resin expanded when processed by the conventional method. Meanwhile, mild shrinkage, possibly polymerization shrinkage, was observed when the resin was processed by the low-temperature method. This suggested that polymerization shrinkage was compensated for by thermal expansion during processing by the conventional method. Moreover, the shrinkage strains in the period from the completion of processing to immediately after de-flasking, in both the conventional and low-temperature methods, were identical to the theoretical value of thermal shrinkage which we obtained by multiplying the linear coefficients of thermal expansion by temperature differences. The shrinkage strain in the specimen processed by the low-temperature method, measured from the end of processing to immediately after de-flasking, averaged 64% of that in the specimen processed by the conventional method. The results revealed quantitatively that the shrinkage of heat-activated acrylic denture-base resin was mainly thermal shrinkage, and demonstrated the advantage of the low-temperature method in reducing thermal shrinkage.
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