We have previously demonstrated in a series of searches for antithrombotic agents that diadenosine 5,5ٟ-P 1 , P 4 -tetraphosphate (AppppA) and its analogues are competitive inhibitors of ADP-induced platelet aggregation. Among various analogues, the P 2 , P When tested for their inhibitory effects on platelet aggregation by ADP, the most promising agent among them was Ap s pCHClpp s A. Both molecular and functional integrity of this compound proved to be stable in blood at 37؇C for at least 3 h. It also showed an excellent heat stability. This agent inhibits a number of aspects of ADP-induced platelet activation-e.g., release reaction, cytoplasmic calcium mobilization, thromboxane production, fibrinogen binding sites, and platelet factor 3 activity. Moreover, platelet aggregation induced by agonists other than ADP-e.g., arachidonic acid, collagen, and epinephrine-was inhibited partially by Ap s pCHClpp s A. It is concluded that (i) Ap s pCHClpp s A is a promising antiplatelet agent; (ii) it is resistant to blood phosphodiesterases and stable to heat treatment; (iii) platelet aggregation induced by collagen, epinephrine, or arachidonic acid is also inhibited in part by this agent; and (iv) specificity of the inhibitory effects is presented by unmodified adenosine moieties of the agent. Resistance to phosphodiesterases raises the possibility of oral administration.

SummaryThis paper reports experimental measurements of the in-vehicle vibrational behaviour of stage 0&1 child safety seats. Road tests were performed for eight combinations of child, child seat and automobile. Four accelerometers were installed in the vehicles and orientated to measure as closely as possible in the vertical direction; two were attached to the floor and two located at the human interfaces. An SAE pad was placed under the ischial tuberosities of the driver at the seat cushion and a child pad, designed for the purpose of this study, was placed under the child. 4 test runs were made over a pave' (cobblestone) surface for the driver's seat and 4 for the child seat at both 20 km/h and 40 km/h. Power spectral densities were determined for all m easurement points and acceleration transmissibility functions (ATFs) were estimated from the floor of the vehicle to the human interfaces. The system composed of automobile seat, child seat and child was found to transmit greater vibration than the system composed of automobile seat and driver. The ensemble mean transmissibility in the frequency range from 1 to 60 Hz was found to be 77% for the child seat systems as opposed to 61% for the driver's seats. The acceleration transmissibility for the child seat system was found to be higher than that of the driver's seat at most frequencies above 10 Hz for all eight systems tested. The measured ATFs suggest that the principal whole-body vibration resonance of the children occurred at a mean frequency of 8.5, rather than the 3.5 to 5.0 Hz typically found in