On intergenerational equity and its clash with intragenerational equity and on the need for policies to guide the regulation of disposal of wastes and other activities posing very long-term risks.

This article begins with some history of the derivation of 40 CFR Part 191, the U.S. Environmental Protection Agency (EPA) standard that governs the geologic disposal of spent nuclear fuel and high-level and transuranic radioactive wastes. This is followed by criticisms of the standard that were made by a Sub-Committee of the EPA Science Advisory Board, by the staff of the U.S. Nuclear Regulatory Commission, and by a panel of the National Academies of Science and Engineering. The large disparity in the EPA approaches to regulation of disposal of radioactive wastes and disposal of hazardous, long-lived, nonradioactive chemical waste is illustrated. An examination of the intertwined matters of intergenerational equity and the discounting of future health effects follows, together with a discussion of the conflict between intergenerational equity and intragenerational equity. Finally, issues related to assumptions in the regulations concerning the future state of society and the biosphere are treated, as is the absence of any national philosophy or guiding policy for how to deal with societal activities that pose very long-term risks.

Direct cytotoxicity of polymorphonuclear leukocyte granule proteins to human lung-derived cells and endothelial cells.

Neutrophils, in the course of defending the host against microbial invasion, release a potent arsenal of proteins that can potentially damage host tissues. Defensins are major peptides of human polymorphonuclear leukocyte (PMN) granules and are both broadly microbicidal and cytotoxic to several tumor cell lines. To determine whether these peptides could play a role in neutrophil-mediated lung injury, we examined the cytotoxicity of defensins and other PMN granule proteins in a chromium release assay with human lung-derived cell lines MRC-5 (lung fetal fibroblast), A549 (lung adenocarcinoma with features of alveolar epithelium), and primary cultures of human umbilical vein endothelial cells (HUVEC). Crude fractionation of an acid extract of human PMN granules yielded four fractions A-D. Only fraction D (containing mostly defensins) was significantly cytotoxic to all three target cells. In contrast, fraction A (containing myeloperoxidase and lactoferrin) and fraction C (containing lysozyme) had little effect, and fraction B (containing chiefly cathepsin G and elastase) was only injurious to endothelial cells. The cytotoxicity of whole PMN granule extracts on pulmonary epithelial and fibroblast targets could be completely accounted for by their defensin content. Fraction D- and defensin-mediated cytotoxicity was concentration dependent, required at least 10 to 12 h to become manifest, and was inhibited by serum. The role of these peptides in lung damage during acute and chronic inflammation deserves further study.

Metabolic acidosis not due to lactic acidosis in patients with severe acute asthma.

Asthmatics seeking emergency care for severe acute asthma may show metabolic acidosis. We sought to determine the frequency of metabolic acidosis in such patients and to assess the relative contributions of renal bicarbonate loss and lactic acid accumulation to this acidosis. Twenty-two asthmatics (21-71 yr; four males, and 18 females) who came consecutively to the emergency department with severe acute asthma were studied. Most patients reported that their asthmatic symptoms had begun to worsen greater than or equal to 2 days before the emergency department visit. Within several hours, simultaneous measurements of arterial blood gases, whole blood lactate, and serum electrolytes were made. Ten of 22 patients were found to have metabolic acidosis (base deficit greater than 2 mEq/L). All ten patients had nonanion gap acidosis, while nine of ten had whole blood lactate values in the normal range (0.33 to 2.55 mmol/L). In the one patient with an elevated whole blood lactate level, the concentration of lactate in excess of normal (0.45 mmol/L) could not account for the magnitude of the base deficit (-4.9 mEq/L). We conclude that a) nonanion gap metabolic acidosis is very common in asthmatics with acute severe asthma (prevalence 45% in our series), and b) the mechanism of the base deficit in these patients is excessive renal bicarbonate excretion. We believe that the latter occurs as a renal compensatory response to a preceding period of hypocapnia due to hyperventilation related to worsening asthma.

Cardiorespiratory patterns in viral septicemia.

Viral infections are known to produce hypotension and shock, but the cardiorespiratory patterns associated with viral septic shock have not been described. The clinical course of nine patients who died from overwhelming cytomegalovirus sepsis was reviewed. Viral septicemia was associated with increased cardiac index, decreased systemic vascular resistance index (SVRI), and elevated oxygen delivery. This pattern appeared during early and late stages of shock. In contrast to bacterial sepsis and endotoxemia, the pulmonary vascular resistance index (PVRI) was normal. These results indicate that overwhelming viral infection can produce shock associated with a high cardiac output, low peripheral resistance state similar to that seen with bacterial shock. Relative sparing of the pulmonary circulation in viral shock is consistent with the absence of endotoxemia in these patients.

The safety goals of the U.S. Nuclear Regulatory Commission.

In August 1986, after 6 years of effort, the U.S. Nuclear Regulatory Commission adopted a Policy Statement on safety goals for nuclear power reactors. The commission's qualitative goals state that individual members of the public should be provided a level of protection from the consequences of nuclear power plant operation such that they bear no significant additional risk to life and health, and societal risks to life and health from nuclear power should be comparable to or less than the risks of generating electricity by viable competing technologies and should not be a significant addition to other societal risks. The commission's safety goal Policy Statement also includes quantitative design objectives.

Spontaneous esophageal hematoma diagnosed by computed tomography.

An 82-year-old woman with acute chest pain was found to have an elongated mass inseparable from the esophagus on CT examination. Hyperdense areas within the mass indicated the diagnosis of spontaneous hematoma of the esophageal wall. She recovered completely without treatment.

Comment on societal risk.

There is a need to measure societal risk more accurately; to examine and reevaluate our priorities in risk reduction; to determine the level of expenditure for risk reduction beyond which adverse economic and political effects may be overriding; and to develop a national approach to risk management.

Differential recovery of Streptococcus mutans from various mitis-salivarius agar preparations.

Recoveries of Streptococcus mutans from human dental plaque were lower when plated on mitis-salivarius agar obtained from Baltimore Biological Laboratories as compared with mitis-salivarius agar obtained from Difco Laboratories. However, no difference in recoveries of established laboratory strains of S. mutans was observed between these two agar preparations.