Intramuscular Exposure to a Lethal Dose of Ricin Toxin Leads to Endothelial Glycocalyx Shedding and Microvascular Flow Abnormality in Mice and Swine

Ricin toxin isolated from the castor bean (Ricinus communis) is one of the most potent and lethal molecules known. While the pathophysiology and clinical consequences of ricin poisoning by the parenteral route, i.e., intramuscular penetration, have been described recently in various animal models, the preceding mechanism underlying the clinical manifestations of systemic ricin poisoning has not been completely defined. Here, we show that following intramuscular administration, ricin bound preferentially to the vasculature in both mice and swine, leading to coagulopathy and widespread hemorrhages. Increased levels of circulating VEGF and decreased expression of vascular VE-cadherin caused blood vessel impairment, thereby promoting hyperpermeability in various organs. Elevated levels of soluble heparan sulfate, hyaluronic acid and syndecan-1 were measured in blood samples following ricin intoxication, indicating that the vascular glycocalyx of both mice and swine underwent extensive damage. Finally, by using side-stream dark field intravital microscopy imaging, we determined that ricin poisoning leads to microvasculature malfunctioning, as manifested by aberrant blood flow and a significant decrease in the number of diffused microvessels. These findings, which suggest that glycocalyx shedding and microcirculation dysfunction play a major role in the pathology of systemic ricin poisoning, may serve for the formulation of specifically tailored therapies for treating parenteral ricin intoxication.     

Wiring harness design and fabrication for the L-1011

A computer-based system for the design and fabrication of aircraft wiring is described. Electronic data processing was used to take advantage of the computer's ability to process and distribute in a timely manner the large volumes of wiring data which are required for a large aircraft such as the Lockheed L-1011 TriStar. Reducing human error was also important, since errors in production data result in extremely costly rework in order to deliver a functioning aircraft.The system has two engineering databases: a wire-list database of point-to-point wiring information and a computer graphics database of system interconnection schematics. The wire list and schematics are compared by computer to ensure error-free engineering data. Two additional databases, one which determines fabrication sequence and another which controls and schedules the release of fabrication documents, complete the system. The wire list and fabrication sequence databases are combined to produce all documents required to fabricate, test and install wiring harnesses.     

Preparation and properties of viscose staple fibre modified by grafting polyvinyl chloride

Conclusions 1. The authors have obtained modified viscose fibres containing PVC in amounts reaching 25–230% of the weight of cellulose. The molecular weight of the grafted chain varies between 40,000 and 140,000; the degree of conversion of cellulose does not exceed 13–22%.2. It is shown that grafting of PVC increases the absolute strength and elongation of fibres, reduces the loss of wet strength, and reduces the resistance to repeated bending. A marked reduction of the fibre number reduces their strength.3. The results are explained by the probability that graft copolymerization takes place on a supramolecular level.Moscow Textile Institute. Translated from Khimicheskie Volokna, No. 5, pp. 30–32, September–October, 1969.     

MECHANISM OF THE HARDENING OF CLAY-SODIUM-SILICATE MIXTURES*

Acid salts, such as might be expected to be present in clays, reacted readily with sodium-silicate solutions and produced marked changes in viscosity out of contact with air. Magnesium salts gave the most gelatinous and bulky precipitates. Experiments with fuller's earth and a plastic fire clay, which were free of soluble salts and were saturated with hydrogen, indicated that base-exchange reactions may also cause hardening of silicate mixtures out of contact with air. Natural plastic fire clays, which contained negligible amounts of soluble salts, were found to harden out of contact with air when calcium and magnesium were present as exchangeable bases, but they did not harden when these bases were absent. It was found possible to prevent hardening of clay-sodium-silicate mixtures by subjecting the clay to a preliminary treatment with nonprecipitating sodium ions, introduced as sodium carbonate, before mixing the clay with sodium silicate.