Government Reference Publication
Excerpt: Intense lead exposure has been linked since antiquity to serious, sometimes lethal disturbances in cardiac rhythmicity and contractile function. More subtle effects have been reported following lead exposure at lower levels; in some instances effects have been reported at levels approaching those encountered passively in the general environment (1-6). These observations suggest that acute and chronic lead exposure over a relatively broad dose range may be associ...
Excerpt: Inhaled and deposited man-made vitreous fibers (MMVF) 10a (low-fluorine preparation of Schuller 901 insulation glass) were studied by electron microscopy in hamster lungs, fixed by intravascular perfusion within 23 +/- 2 min (SD) of the initial inhalation. We found fibers on the surfaces of conducting airways and alveoli. In the airways, 89% of the fibers were totally and 11% partially covered by lining-layer material. In the alveoli, 32% of the fibers were tota...
Introduction: Some unexpected soil pollution occurred in Michigan as a result of the accidental addition of an industrial flame retardant, FireMaster BP-6 (a mixture of polybrominated biphenyls, or PBBs), to livestock feed in place of magnesium oxide (14). This incident led to contamination of many Michigan farm soils through disposal of PBB-tainted manure, milk, feed, and dust cleanings from buildings, etc. This contamination posed questions about the fate of PBBs in so...
Excerpt: The National Institutes of Health, owing to its broad mandate to pursue and support acquisition of knowledge in biomedicine, is very much concerned with any investigations leading to better understanding of the causes and control of human diseases. One approach is to study health and illness in special subsets of the United States population and of populations in foreign countries. In this paper, I shall touch briefly on a number of health roblemsan d disease-or...
Excerpt: The media, Gulf War veterans, and some scientists have suggested that illnesses observed among veterans after the war are attributable to deployment-related exposures (1). Gulf War veterans have reported a higher prevalence of symptoms than contemporaneous soldiers not deployed to the war for many illnesses, including bronchitis and asthma (2?10). Principal respiratory exposures that occurred during the war include combustion products, chemical agent-resistant c...
Excerpt: In the air pollution arena, the spotlight is now shining on a series of studies conduct- ed over the vast 5 vears which indicates that rhousands of deaths a year are caused by inhaling tiny particles of soot, emitted Mainly from industrial sites.
Excerpt: Until the fall of 1992, methyl tertiary butyl ether (MTBE) was used as an octane enhancer in premium gasolines. To bring several regions of the United States into compliance with the National Ambient Air Quality Standards for carbon monoxide, the 1990 Clean Air Act (1) mandated 2.7% by weight oxygen concentration in cold season fuels and 2.0% by weight oxygen during photochemical smog season. Although both MTBE and ethanol can be used to oxygenate fuel, MTBE was...
Excerpt: It was a dramatic day in the history of radioactive contamination in the former Soviet Union. On 15 December 2000, a Ukrainian engineer flipped a switch at Chornobyl (formerly Chernobyl), and the infamous nuclear power plant?or rather, what was left after the 1986 explosion that sent eight tons of airborne radioactive particles across the region and into nearby countries?was finally shut down. After long resisting the closure because of the need for the energy p...
Excerpt: Mammary tumorigenesis by N-substituted aryl compounds has been intensely studied in the rat. the most susceptible species. Enhancement of carcinogenic activity by N-hydroxylation of N-arylamides was clearly demonstrated in immature female rats (Table 1). The examples include the N-hydroxy metabolites of N-2-fluorenylacetamide (FAA) and of N-4-biphenylacetamide (CBPAA), discovered and tested 20 years ago by the Millers and ceworkers (1, 2) and synthetic compounds...
Excerpt: In recent years, routine methods, based primarily on animal death and/or histopathological changes, have evolved to assess the toxicity and/or carcinogenicity of environmenta- l pollutants. These approaches have aided in the identification of certain highly toxic envimnmen- contaminants with acute effects (1). The develop- of assays and/or batteries of techniques t deter- mine the effects of these agents on more subtle cell functions has not evolved as rapidly, and indeed in.
Excerpt: The initial problem for the experimental pathologist in evaluating neoplasia in the upper respiratory tract and, in particular, the nasal cavity, is the selection of a widely acceptable tumor classification system. The choice largely depends on the pathologists personal experience and on the personal biases that develop as the full range of lesions unfolds.
Excerpt: High concentrations of airborne particles have been associated with increased pulmonary and cardiovascular mortality, with indications of a specific toxicologic role for ultrafine particles (UFPs; particles < 0.1 micrometer). Within hours after the respiratory system is exposed to UFPs, the UFPs may appear in many compartments of the body, including the liver, heart, and nervous system. To date, the mechanisms by which UFPs penetrate boundary membranes and the d...
Excerpt: Despite extensive research, the etiology of childhood cancer is largely unknown. Considering the early onset of many childhood cancers?especially childhood acute lymphocytic leukemia, which is most common in children aged 2?5 years?risk factors occurring very early in life, during pregnancy, or even before conception must be considered. During the last decades, several studies have focused on parental occupational exposures that occurred prenatally as possible r...
Excerpt: The influence of climate and the environment on infectious diseases has been a subject of debate, speculation, and serious study for centuries. Jacob Henle (I) stated in his 1840 ueatise On Miusmata and Conrugia Heat and moisture favor the production and propagation of the infusoria and the molds, as well as the miasmata and wntag-i a, therefore miasmatic-cont-a ouds iseases are most often endemic in warm moist regions and epidemic in the wet summer months. He i...
Excerpt: Hazardous effects of an effluent from the chrome plating industry were examined by exposing transgenic Drosophila melanogaster (hsp70-lacZ) to various concentrations (0.05, 0.1, 1.0, 10.0, and 100.0 ?L/mL) of the effluent through diet. The emergence pattern of adult flies was affected, along with impaired reproductive performance at the higher dietary concentrations of the effluent. Interestingly, the effect of the effluent was more pronounced in male than in fe...
Excerpt: Several halogenated alkenes, e.g., hexachlorobuta- (HcBD), perfluoropropene (PFP), trichlorotri- (TCTFP), and the alkyne dichloroacety- the lene (DCA), are selectively nephrdtoxic in rats and intluce proximal tubular damage (I) . Moreover, the widely used solvents trichloroethene and tetrachlo- roethene, DCA, and HCBD induce carcinoma of the proximal tubules in rats. Recent studies that have sought an explanation for the selective nephrotoxicity and-carcinogenic...
Excerpt: Cameron Park, Texas, is a colonia (an isolated, unincorporated rural settlement without municipal improvements) on the Texas?Mexico border in the Lower Rio Grande Valley, in Cameron County near Brownsville, Texas. Cameron Park has a population of 5,961 residents, 99.3% of whom are Hispanic. The annual median income is $16,934, about one-half of the state median. Fifty-eight percent of families generally and 68% of those with children younger than 5 years have in...
Excerpt: Particulates and complex organic mixtures were sampled from the exhaust of a Rame retention head residential oil burner combusting No. 2 fuel oil at three firingconditions: continuous at Bacharach Smoke No. 1, and cyclic (5 min on, 10 min off) at Smoke Nos. 1 and 5. The complex mixtures were recovered by successive Soxhlet extraction of filtered particulates and XAD-2 sorbent resin with methylene chloride (DCM) and then methanol (MeOH). Bacterial mutae..e nicitv...
Excerpt: During the past several decades, philosophers of science and scientists themselves have become increasingly aware of the complex ways in which scientific knowledge is shaped by its social context. This awareness has called into question traditional notions of objectivity. Working scientists need an understanding of their own practice that avoids the na?ve myth that science can become objective by avoiding social influences as well as the reductionist view that i...
Excerpt: 1,3-Butadiene is a colorless, flammable, noncorrosive gas (bp: -4.4 C, Vp: 1900 mmHg at 20 C) used mainly in the production of synthetic rubber and thermoplastic resins (1). In production volume, 1,3-butadiene is one of the top 25 organic chemicals manufactured in the United States (2), with an annual production level of rubbergrade 1,3-butadiene in the U.S. of approximately 2.5 billion pounds (3). This gas has also been identified in automobile exhaust, cigaret...