The purpose of this study was to investigate the effect of voluntary exercise on osteoinductive activity in rat bone. Sprague-Dawley male and female rats were allowed to exercise freely by running on a treadmill or kept as controls without exercise for 53 days. Decalcified humeral diaphyses from experimental and control rats were implanted intraperitonealy into host rats and harvested after 33 days. A significant increase in bone formation was confirmed in the implanted bone matrices from the running group in comparison with those from control animals by soft X-ray photography and determination of alkaline phosphatase activity and mineral content. Alkaline phosphatase activity in bone and serum was increased by exercise in both male and female animals. The results suggest that osteoinductive activity in the bone was probably due to increased levels of bone morphogenetic protein following voluntary exercise.
Early events in the infection of human B lymphocytes by Epstein-Ban virus (EBV) were examined by measuring calcium ion concentration from fluorescence with fura-2. Intracellular Ca ion concentration ([Ca2+]i) of B lymphocytes increased in response to EBV application. Three types of [Ca2+]i-increase were observed: (1) an early transient [Ca2+]i-increase; (2) an early transient [Ca2+]i-increase followed by a slow sustained [Ca2+]i-increase; and (3) a slow [Ca2+]i-increase without the early transient [Ca2+]i-increase. The early transient increase was observed in the zero Ca2+ condition, but it was suppressed when cells were pretreated with ryanodine before exposure to the virus. The slow sustained [Ca2+]i increase was not obse1ved in Ca2+-free extracellular conditions.
These results suggest that the early transient [Ca2+]i increase is mediated by Ca2+ release from intracellular Ca storage sites, and the slow sustained [Ca2+]i increase is mediated by the Ca2+ influx through the plasma membrane. Virus receptors on the surface of B lymphocytes were stained with a fluorescence marker, rhodamine, and the capping process after EBV application was observed under a confocal microscope. The capping process and the localization of virus receptors were observed after EBV application. The time course of the capping process seems similar to that of the slow, sustained [Ca2+]i increase.
Intracellular recordings were made from bullfrog sympathetic ganglion cells to elucidate effects of 2-n-butyl-1-(4-methylpiperazinyl)-5,6-methylenedioxyindene・2HCI (TN-871) on synaptic transmission. TN-871 at 30 nM augmented cholinergic nicotinic fast excitatory postsynaptic potentials (fast EPSPs), whereas the drug at 3 µM reversibly depressed them, without affecting acetylcholine induced depolarizations. TN-871 did not affect active and passive electrical properties of the ganglion cells. The quantal analysis method was applied to the fast EPSPs in a 0.54 mM Ca2+/7.56 mM Mg2+ Ringer’s solution. The mean quantal content was significantly increased by TN-871 at 30 nM but significantly at 3 µM. TN-871 at 300 nM either increased or decreased the mean quantal content. The mean quanta! size of the fast EPSPs was not changed by TN-871 at the concentrations examined. Fast EPSPs in a 0.99 mM Ca2+/4.86 mM Mg2+ Ringer’s solution were not decreased affected by nicardipine, but were inhibited in amplitude by w-conotoxin in a concentration dependent manner. It is likely that TN-871, in high concentrations, might block w-conotoxin sensitive N-type calcium channels in the presynaptic terminals. These results indicate that TN-871 modulates transmitter release from preganglionic nerve terminals without changing the postsynaptic sensitivity of the ganglion cells to ACh.
The purpose of this study was to evaluate dental attrition by measuring attrition volume on all types of teeth during facial growth, tooth shedding and eruption. Dental casts and cephalograms of 7 male and 7 female Mayan Tzutujil Indian children were used
Relationships were found between increase in vertical and horizontal facial growth and increase in attrition on the deciduous canines, first and second molars, permanent incisors and first molars in both arches and in both sexes. Significant increases in attrition were found on the deciduous second molars during eruption of the permanent first molars, and on the permanent incisors and first molars during eruption of the second molars in both arches and in both sexes.
The results suggest that the function of attrition is 1) to compensate for increase in vertical and horizontal dimensions during facial growth, and 2) to adjust the occlusal surfaces during tooth eruption and occlusal development.
In addition, an attritional index was developed to evaluate attrition among teeth. This index could be used in the future to make comparisons among different populations. Comparisons were made among Class I, II and III molar relations by using the attritional index, showing how it can be used to gain a better understanding of the characteristic patterns of dental attrition.
Monoclonal antibodies against alkaline phosphatase [ALP; ortho-phosphoric monoester phosphohydrolase, alkaline optimum, EC 18.104.22.168.] of cultured human osteoblast-like cells (HBC) were raised in mice. Immuno-reactions of tissue-nonspecific type ALP from human bone, dental pulp, liver and kidney as well as intestinal and placental types to the monoclonal antibodies were compared by a dot immunoassay and ELISA. One clone was able to recognize antigenic differences among tissue-nonspecific type ALPs in addition to intestinal and placental ALPs; it reacted favorably with ALPs from HBC, human bone, kidney and dental pulp, but not with human liver enzyme. Similarly, the antibody immunoreacted with bone-derived ALP but not with liver-derived enzyme present in human serum.
The present monoclonal antibody preparation can be utilized in basic studies as well as in clinical laboratory tests to distinguish minor heterogeneity among human ALPs.