Estimating separately personal exposure to ambient and nonambient particulate matter for epidemiology and risk assessment: why and how.

This paper discusses the legal and scientific reasons for separating personal exposure to PM into ambient and nonambient components. It then demonstrates by several examples how well-established models and data typically obtained in exposure field studies can be used to estimate both individual and community average exposure to ambient-generated PM (ambient PM outdoors plus ambient PM that has infiltrated indoors), indoor-generated PM, and personal activity PM. Ambient concentrations are not highly correlated with personal exposure to nonambient PM or total PM but are highly correlated with personal exposure to ambient-generated PM. Therefore, ambient concentrations may be used in epidemiology as an appropriate surrogate for personal exposure to ambient-generated PM. Suggestions are offered as to how exposure to ambient-generated PM may be obtained and used in epidemiology and risk assessment.

Spindle cell squamous carcinoma of the esophagus: analysis of ploidy and tumor proliferative activity in a series of 13 cases.

Spindle cell squamous esophageal carcinomas are distinctive polypoid "biphasic" tumors in which the sarcoma-like phenotype usually predominates over the epithelial component. To biologically assess both phenotypes, we compared the tumoral proliferative activity and DNA ploidy between the two histological components of 13 polypoid spindle cell squamous carcinomas of the esophagus. We studied the tumoral proliferative index (TPI) using MIB 1 monoclonal antibody (Ki-67) and determined the DNA histogram by image cytometry on Feulgen-stained sections. The DNA histograms were classified into four types (I to IV) according to the degree of dispersion of the DNA. The TPI of the carcinomatous regions ranged from 0.20 to 0.63 (mean, 0.44) and from 0.55 to 0.85 for the sarcoma-like areas (mean, 0.68) P < .0001. In all cases, the sarcoma-like areas were aneuploid, and 37.5% of the carcinomatous regions were diploid. Also, in all instances the carcinomatous areas were of either histogram type I or II, and the sarcoma-like areas showed histograms of type II or III. We conclude that in esophageal spindle cell squamous carcinomas the sarcoma-like phenotype differs biologically in two ways from the carcinomatous: (1) it has a higher TPI and (2) it has higher aneuploidy with a greater dispersion of the DNA content. We postulate that these characteristics could give a "growth" advantage to the sarcoma-like component of these tumors and explain its predominance over the carcinomatous component.

Advance directives and do not resuscitate orders: nurses' knowledge and the level of practice in school settings.

A descriptive, correlational study was conducted among school nurses to ascertain their knowledge of Advance Directives (ADs) and Do Not Resuscitate (DNR) orders, current AD and DNR practice in the school setting, and personal AD and DNR attitudes and plans of study respondents. A convenience sample of practicing school nurses was surveyed using an author-designed instrument. Results indicated a need to increase knowledge regarding ethical principles and advance directives. Eleven percent of the respondents reported school district policies in place regarding advance directives/DNR orders. Seventy-eight percent of respondents indicated they have no personal advance directives in place, but 76% would not wish to be resuscitated when facing terminal illness. These results suggest ambiguity regarding issues of death and dying.

Hepatic undifferentiated (embryonal) sarcoma arising in a mesenchymal hamartoma.

We report the case of a hepatic undifferentiated (embryonal) sarcoma (UES) arising within a mesenchymal hamartoma (MH) in a 15-year-old girl. Mapping of the tumor demonstrated a typical MH transforming gradually into a UES composed of anaplastic stromal cells. When evaluated by flow cytometry, the MH was diploid and the UES showed a prominent aneuploid peak. Karyotypic analysis of the UES showed structural alterations of chromosome 19, which have been implicated as a potential genetic marker of MH. The histogenesis of MH and UES is still debated, and reports of a relationship between them, although suggested on the basis of histomorphologic similarities, have never been convincing. The histologic, flow cytometric, and cytogenetic evidence reported herein suggests a link between these two hepatic tumors of the pediatric population.

Adenomatoid tumor of the adrenal gland: a report of four new cases and a review of the literature.

Adenomatoid tumors of the adrenal gland are rare, benign, asymptomatic neoplasms that are usually found incidentally. Previously reported cases occurred only in men and only on the left side. We report four cases, including two from the right adrenal gland, one from a woman, and one with a cystic component. The average age of our patients was 49 years, compared with the average age of 34 years in previously reported cases. Our immunohistochemical stains and electron microscopic analysis support the presumed mesothelial derivation of these tumors. The differential diagnosis of adenomatoid tumors of the adrenal gland includes a variety of solid and cystic tumors. It is important to recognize these rare tumors to avoid misclassifying them, especially as metastatic or primary malignant vascular tumors.

Unbalanced chromosomal translocation, der(17)t(13;17)(q14;p11) in a solid and cystic papillary epithelial neoplasm of the pancreas.

We report on a solid and cystic papillary epithelial neoplasm of the pancreas containing the unbalanced chromosome translocation der(17)t(13;17)(q14;p11), resulting in loss of 13q14-->qter and 17p11-->pter. Although the clinical and pathologic characteristics of this case are largely typical of this uncommon pancreatic neoplasm, the presence of cellular pleomorphism, tumor giant cells, and a DNA tetraploid tumor population suggest that this tumor may have an increased metastatic potential. The unbalanced translocation between chromosomes 13 and 17 and the genes flanking the breakpoints may prove to be markers for solid and cystic papillary epithelial neoplasm of the pancreas and provide insight into its histogenesis.

Effects of ageism on individual and health care providers' responses to healthy aging.

Although misconceptions about the aging process have lessened over recent years, ageism is still having a detrimental effect on healthy aging. This article reviews the literature to support this contention and to demonstrate how stereotyping can affect the shape and nature of programs for elderly people. It is argued that for long-lasting change to occur, service providers need to directly target these negative attitudes in themselves, their professional institutions, their clients, and their communities. Suggestions are made for professional development, research, and program planning.

Current issues in human lead exposure and regulation of lead.

Concern about lead as a significant public health problem has increased as epidemiological and experimental evidence has mounted regarding adverse health effects at successively lower levels of lead exposure. This concern has led to downward revision of criteria for acceptable blood lead concentrations to the 10 micrograms/dL mark now designated by EPA as a target level for regulatory development and enforcement/clean-up purposes. Much progress has been made in reducing lead exposures during the past 10-15 years, with marked declines evident both in air lead and blood lead concentrations in parallel to the phase-down of lead in gasoline and notable decreases in food lead exposure due to elimination of lead soldered cans by U.S. food processors. With the lessening of exposure from these sources, the importance of other components of multimedia exposure pathways has grown and stimulated increasing regulatory attention and abatement efforts to reduce health risks associated with lead exposure from drinking water, from lead-based paint, and from household dust and soil contaminated by deteriorating paint, smelter emissions, or various other sources. Increasing attention is also being accorded to reduction of occupational lead exposures (including those related to lead abatement activities), with particular concern for protection of men and women during their reproductive years.

Research on risk assessment and risk management: future directions.

This paper has been reviewed by the Office of Health and Environmental Assessment, U.S. Environmental Protection Agency, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. The U.S. EPA has increasingly relied upon quantitative health risk assessments as the basis for management decisions about public health protection. Full utilization of risk assessment in management applications, however, is limited by uncertainties in the resultant accuracy of the risk estimates. This paper will discuss a research strategy to address the uncertainties in the risk assessment process and describe parallel issues to address in the risk management area. An attendant need for effective communication of complex scientific concepts is also identified.

The comparative developmental neurotoxicity of lead in humans and animals.

The effects of lead on neurobehavioral development have been extensively investigated in humans as well as animals. This valuable lode of research findings offers a basis for comparing the developmental neurobehavioral toxicity of lead across species and for assessing the validity of animal models of developmental neurotoxicity. Comparisons of human and animal findings suggest that the greatest qualitative similarities involve relatively complex behavioral processes such as cognition and learning. Quantitative comparisons based on dose-response relationships for these endpoints are difficult to make because the relationships are sometimes nonmonotonic (U-shaped) and because blood lead levels may not be directly comparable between species. However, the lowest levels of exposure at which developmental neurobehavioral effects have been observed are similar: 10-15 micrograms/dl in children, less than 15 micrograms/dl in primates, and less than 20 micrograms/dl in rodents. Although the convergence between animal and human findings for other neurobehavioral endpoints is not as striking, sensory-evoked potentials and communicative processes offer two promising areas for continued investigation and cross-species comparison.

Prenatal and postnatal effects of low-level lead exposure: integrated summary of a report to the U.S. Congress on childhood lead poisoning.

This article provides an integrated summary of a report to Congress from the Federal government (ATSDR) on childhood lead poisoning in the United States, with particular reference to low-level lead exposure and its effects on the fetus and the preschool child. As mandated by Section 118(f)(1)(C) of the 1986 Superfund Amendments and Reauthorization Act (SARA), ATSDR has examined the full spectrum of human in utero and postnatal lead toxicity, with emphasis on low-level neurotoxicity and adverse impacts on growth indices in risk populations. Especially important has been assessment of the relative persistence of these effects in later life as discernible from a number of longitudinal studies now under way around the world. Included in the Congressional report were discussions of dose-effect and dose-response relationships using blood lead levels as the indicator of lead dose.

Chronic neonatal organotin exposure alters radial-arm maze performance in adult rats.

Long-Evans rats were intubated with 0.3 or 1.0 mg/kg of triethyltin sulfate (TET) or 0.3 mg/kg of trimethyltin hydroxide (TMT) from postnatal day 3-29. 1.0 mg/kg of TMT was given on alternate days beginning on postnatal day 3. Learning and memory were assessed in an automated radial-arm maze when the rats were 180-200 days old. With this maze accuracy and activity data can be collected simultaneously. TET or TMT treatment resulted in an increase in the number of days required to adequately perform and radial-arm maze task, and a transient deficit in accuracy. However, the most pronounced effect in both TET and TMT-treated animals was hyperactivity which became manifest on the second day of testing and persisted throughout the remainder of testing.