Minimization and management of wastes from biomedical research.

Several committees were established by the National Association of Physicians for the Environment to investigate and report on various topics at the National Leadership Conference on Biomedical Research and the Environment held at the 1--2 November 1999 at the National Institutes of Health in Bethesda, Maryland. This is the report of the Committee on Minimization and Management of Wastes from Biomedical Research. Biomedical research facilities contribute a small fraction of the total amount of wastes generated in the United States, and the rate of generation appears to be decreasing. Significant reductions in generation of hazardous, radioactive, and mixed wastes have recently been reported, even at facilities with rapidly expanding research programs. Changes in the focus of research, improvements in laboratory techniques, and greater emphasis on waste minimization (volume and toxicity reduction) explain the declining trend in generation. The potential for uncontrolled releases of wastes from biomedical research facilities and adverse impacts on the general environment from these wastes appears to be low. Wastes are subject to numerous regulatory requirements and are contained and managed in a manner protective of the environment. Most biohazardous agents, chemicals, and radionuclides that find significant use in research are not likely to be persistent, bioaccumulative, or toxic if they are released. Today, the primary motivations for the ongoing efforts by facilities to improve minimization and management of wastes are regulatory compliance and avoidance of the high disposal costs and liabilities associated with generation of regulated wastes. The committee concluded that there was no evidence suggesting that the anticipated increases in biomedical research will significantly increase generation of hazardous wastes or have adverse impacts on the general environment. This conclusion assumes the positive, countervailing trends of enhanced pollution prevention efforts by facilities and reductions in waste generation resulting from improvements in research methods will continue.

Gel-filtered human platelets. Ultrastructure, function, and role of proteins in inhibition of aggregation by aspirin.

Gel filtration of human platelet-rich plasma (PRP) on columns of Sepharose 2B removed at least 99.85% of the plasma proteins from platelets when a column 10 cm in height was used and a plasma volume 11 to 14% of the gel-bed volume was applied. ADP and ATP levels in gel-filtered platelets (GFP) were not significantly different from those in PRP. By transmission electron microscopy, GFP were indistinguishable from PRP. Gel filtration appears to be a highly satisfactory technique of separating platelets from plasma without modifying structure, function, or contents significantly. The roles of several crude protein fractions in platelet aggregation and aspirin's inhibition of aggregation were examined. Fraction I (mostly fibrinogen) enhanced collagen-induced aggregation of gel-filtered platelets; Fraction V (mostly albumin) was inhibitory. Fraction II (mostly gamma-globulin) or gelatin had no significant effect. Aspirin added to gel-filtered platelets inhibited aggregation by 80%. The addition of mixtures of plasma proteins containing albumin increased albumin's inhibitory effect. Incubation of gel-filtered platelets with aspirin labeled in the carboxyl position resulted in no uptake of the label. In contrast, incubation with acetyl-labeled aspirin was followed by uptake of more than 2 X 10(6) acetyl groups per platelet in 1 minute. Incubation for 30 minutes resulted in a five- to sixfold further increase in uptake of the label. Aspirin can acetylate platelets and inhibit aggregation directly. Plasma proteins, in particular albumin or a contaminant of the albumin fraction tested, enhance the inhibitory effect of aspirin on platelet aggregation.