The susceptibility of the Indonesian I/CDC strain of Plasmodium vivax to chloroquine.

A strain of Plasmodium vivax from Indonesia was adapted to splenectomized Aotus and Saimiri monkeys and tested for its susceptibility to chloroquine. Animals were infected by intravenous inoculation of heparinized parasitized blood and subsequently treated with 8 or 15 mg (base) of chloroquine by oral intubation. Recrudescence of infection occurred in 4 of 4 Aotus and 5 of 6 Saimiri monkeys treated with 15 mg base of chloroquine, indicating a level of resistance between that of the standard Chesson strain of P. vivax and the recently reported resistant strains from Papua New Guinea.     

Almost critical ecosystems

We introduce the concept of an almost critical system as one possessing certain critical stability properties when some of the small system parameters are placed equal to zero. We show how the location and stability properties of the critical points of almost critical systems can be deduced from those of the underlying critical system, providing the full mathematical criteria required.     

A mechanical dissociation method for preparation of muscle cell cultures

A cell preparation method by which large numbers of embryonic chick skeletal muscle cells may be obtained is described. The procedure requires fewer manipulations and much less time than standard trypsinization. By the criteria used, both methods are comparable with respect to percent viable cells and survival of plated cells. However, in addition to the ease of preparation, the mechanical dissociation method offers the significant advantage that the cell suspension is greatly enriched for myoblasts without the necessity of an additional preplating step.     

Analysis of services available for total joint replacement surgery.

The use of a total joint replacement surgery has been growing in a manner which is poorly understood. This growth is more likely to be limited by saturation of the available medical services than by a limit to the number of people who could benefit from the treatment. Present indications are that services will be saturated in 1974 or 1975, after which 4600 extra people a year will go on to the waiting lists if demand continues as at present. Stability can then be achieved by either raising the clinical criteria for surgical treatment or making about 300 extra orthopaedic beds available each year, buffered from the demands of acute trauma admissions.