Depression and Handgrip Strength Among U.S. Adults Aged 60 Years and Older from NHANES 2011-2014

OBJECTIVES

Sarcopenia is a gradual loss of muscle mass and strength that occurs with aging. This muscle deterioration is linked to increased morbidity, disability, and other adverse outcomes. Although reduced handgrip strength can be considered a marker of sarcopenia and other aging-related decline in the elderly, there is limited research on this physical health problem in at-risk groups with common biopsychosocial conditions such as depression. Our primary objective was to ascertain level of combined handgrip strength and its relationship with depression among adults aged 60 years and older.

DESIGN

Unadjusted and adjusted linear regression models were conducted with a cross-sectional survey dataset.

SETTING

Secondary dataset from the 2011-2014 National Health and Nutrition Examination Survey (NHANES).

PARTICIPANTS

Community-dwelling, non-institutionalized adults ≥60 years old (n=3,421).

MEASUREMENTS

The predictor variables included a positive screen for clinically relevant depression (referent=PHQ-9 score <10). The criterion variable of combined handgrip strength (kg) was determined using a dynamometer.

RESULTS

Mean age and BMI were 69.9 years (51.5% female) and 28.8 kg/m2, respectively. Mean combined handgrip strength in the overall cohort was 73.5 and 46.6 kg in males and females, respectively. Three hundred thirty-six (9.8%) reported symptoms of depression. In unadjusted and fully adjusted models, depression was significantly associated with reduced handgrip strength (B = -0.26±0.79 and B = -0.19±0.08, respectively; p<0.001).

CONCLUSION

Our findings demonstrate handgrip strength has a significant inverse association with depression. Future longitudinal studies should investigate the causal processes and potential moderators and mediators of the relationships between depression and reduced handgrip strength. This information may further encourage the use of depression and handgrip strength assessments and aid in the monitoring and implementation of health care services that address both physical and mental health limitations among older adult populations.

Smoking Predicting Physical Activity in an Aging America

OBJECTIVES

Tobacco smoking and physical inactivity are among leading behavioral risk factors for ill health in older adults. This study considers how smoking is associated with physical activity.

DESIGN

Using a Life-Course model, data are analyzed regarding this relationship, controlling for, and interacted with, life-course and other factors. Daily smokers and sometimes smokers were hypothesized to engage in less leisure-time physical activity than those who never smoked, while those who stopped smoking were expected to do more than never smokers. Analyses were performed using SAS-Callable SUDAAN.

SETTING AND PARTICIPANTS

Secondary data from ten years of a national sample of adults aged 18 and over of the National Health Interview Survey, 2001-2010, are used (N = 264,945, missing data excluded, of 282,313 total cases).

MEASUREMENTS

Daily smokers, occasional smokers, and smoking quitters are compared to never smokers with regard to requisite physical activity (150 minutes per week of moderate, 100 of vigorous, and/or 50 of strengthening activity). Life-course measures include birth cohorts, age, and year of survey, as well as gender, race/ethnicity, and education.

RESULTS

Overall, hypotheses are supported regarding daily smokers and quitters; but the hypothesis is strongly rejected among sometimes smokers, who are much more likely to do requisite physical activity. Findings differ by age, sometimes smokers age 65 and over being less likely to do physical activity. Findings among all men are similar to the overall findings, while those among all women are similar to those for older respondents. Associations of smoking status with physical activity vary greatly by race/ethnicity.

CONCLUSIONS

Daily smokers may be most in need of both smoking cessation and leisure-time physical activity interventions. Smoking-cessation efforts may pay greater physical activity benefits among women and the aged, while smoking-reduction efforts may provide better outcomes among men. Smoking reduction efforts may pay more exercise benefits among African-Americans and Hispanics.

Cell-specific and developmental expression of lectican-cleaving proteases in mouse hippocampus and neocortex

Mounting evidence has demonstrated that a specialized extracellular matrix exists in the mammalian brain and that this glycoprotein-rich matrix contributes to many aspects of brain development and function. The most prominent supramolecular assemblies of these extracellular matrix glycoproteins are perineuronal nets, specialized lattice-like structures that surround the cell bodies and proximal neurites of select classes of interneurons. Perineuronal nets are composed of lecticans, a family of chondroitin sulfate proteoglycans that includes aggrecan, brevican, neurocan, and versican. These lattice-like structures emerge late in postnatal brain development, coinciding with the ending of critical periods of brain development. Despite our knowledge of the presence of lecticans in perineuronal nets and their importance in regulating synaptic plasticity, we know little about the development or distribution of the extracellular proteases that are responsible for their cleavage and turnover. A subset of a large family of extracellular proteases (called a disintegrin and metalloproteinase with thrombospondin motifs [ADAMTS]) is responsible for endogenously cleaving lecticans. We therefore explored the expression pattern of two aggrecan-degrading ADAMTS family members, ADAMTS15 and ADAMTS4, in the hippocampus and neocortex. Here, we show that both lectican-degrading metalloproteases are present in these brain regions and that each exhibits a distinct temporal and spatial expression pattern. Adamts15 mRNA is expressed exclusively by parvalbumin-expressing interneurons during synaptogenesis, whereas Adamts4 mRNA is exclusively generated by telencephalic oligodendrocytes during myelination. Thus, ADAMTS15 and ADAMTS4 not only exhibit unique cellular expression patterns but their developmental upregulation by these cell types coincides with critical aspects of neural development.

A methanotrophic marine molluscan (bivalvia, mytilidae) symbiosis: mussels fueled by gas

An undescribed mussel (family Mytilidae), which lives in the vicinity of hydrocarbon seeps in the Gulf of Mexico, consumes methane (the principal component of natural gas) at a high rate. The methane consumption is limited to the gills of these animals and is apparently due to the abundant intracellular bacteria found there. This demonstrates a methane-based symbiosis between an animal and intracellular bacteria. Methane consumption is dependent on the availability of oxygen and is inhibited by acetylene. The consumption of methane by these mussels is associated with a dramatic increase in oxygen consumption and carbon dioxide production. As the methane consumption of the bivalve can exceed its carbon dioxide production, the symbiosis may be able to entirely satisfy its carbon needs from methane uptake. The very light (delta(13)C = -51 to -57 per mil) stable carbon isotope ratios found in this animal support methane (delta(13)C = -45 per mil at this site) as the primary carbon source for both the mussels and their symbionts.

Deep-sea hydrocarbon seep communities: evidence for energy and nutritional carbon sources

Mussels, clams, and tube worms collected in the vicinity of hydrocarbon seeps on the Louisiana slope contain mostly "dead" carbon, indicating that dietary carbon is largely derived from seeping oil and gas. Enzyme assays, elemental sulfur analysis, and carbon dioxide fixation studies demonstrate that vestimentiferan tube worms and three clam species contain intracellular, autotrophic sulfur bacterial symbionts. Carbon isotopic ratios of 246 individual animal tissues were used to differentiate heterotrophic (8(13)C = -14 to -20 per mil), sulfur-based (8(13)C = -30 to -42 per mil), and methane-based (8(13)C = <-40 per mil) energy sources. Mussels with symbiotic methanotrophic bacteria reflect the carbon isotopic composition of the methane source. Isotopically light nitrogen and sulfur confirm the chemoautotrophic nature of the seep animals. Sulfur-based chemosynthetic animals contain isotopically light sulfur, whereas methane-based symbiotic mussels more closely reflect the heavier oceanic sulfate pool. The nitrogen requirement of some seep animals may be supported by nitrogen-fixing bacteria. Some grazing neogastropods have isotopic values characteristic of chemosynthetic animals, suggesting the transfer of carbon into the background deep-sea fauna.

Thermogenic gas hydrates in the gulf of Mexico

Thermogenic gas hydrates were recovered from the upper few meters of bottom sediments in the northwestern Gulf of Mexico. The hydrates were associated with oil-stained cores at a water depth of 530 meters. The hydrates apparently occur sporadically in seismic "wipeout" zones of sediments in a region of the Gulf continental slope at least several hundred square kilometers in area.

Stable carbon isotopic evidence for carbon limitation in hydrothermal vent vestimentiferans

Stable carbon isotope composition (delta(13)C values) can be used to evaluate an animal's source of nutritional carbon. Most animals with chemoautotrophic endosymbionts have quite negative tissue delta(13)C values due to discrimination against (13)C associated with chemoautotrophic assimilation of inorganic carbon. However, the delta(13)C values of hydrothermal vent (HTV) vestimentiferans are significantly higher than the values reported for non-HTV vestimentiferans or other invertebrates with chemoautotrophic endosymbionts. Tissue delta(13)C values of two species of HTV vestimentiferans increase with increasing size of the animals. This relation supports the hypothesis that the relatively high delta(13)C values are the result of inorganic carbon limitation during carbon fixation. A more favorable relation between gas exchange and carbon fixation in the smaller individuals is expected, due to differences in the geometric scaling of gas-exchange surfaces and trophosome volume.

Astrocyte-derived kynurenic acid modulates basal and evoked cortical acetylcholine release

We tested the hypothesis that fluctuations in the levels of kynurenic acid (KYNA), an endogenous antagonist of the alpha7 nicotinic acetylcholine (ACh) receptor, modulate extracellular ACh levels in the medial prefrontal cortex in rats. Decreases in cortical KYNA levels were achieved by local perfusion of S-ESBA, a selective inhibitor of the astrocytic enzyme kynurenine aminotransferase II (KAT II), which catalyses the formation of KYNA from its precursor L-kynurenine. At 5 mm, S-ESBA caused a 30% reduction in extracellular KYNA levels, which was accompanied by a two-threefold increase in basal cortical ACh levels. Co-perfusion of KYNA in the endogenous range (100 nm), which by itself tended to reduce basal ACh levels, blocked the ability of S-ESBA to raise extracellular ACh levels. KYNA perfusion (100 nm) also prevented the evoked ACh release caused by d-amphetamine (2.0 mg/kg). This effect was duplicated by the systemic administration of kynurenine (50 mg/kg), which resulted in a significant increase in cortical KYNA formation. Jointly, these data indicate that astrocytes, by producing and releasing KYNA, have the ability to modulate cortical cholinergic neurotransmission under both basal and stimulated conditions. As cortical KYNA levels are elevated in individuals with schizophrenia, and in light of the established role of cortical ACh in executive functions, our findings suggest that drugs capable of attenuating the production of KYNA may be of benefit in the treatment of cognitive deficits in schizophrenia.

Does patent ductus arteriosus affect feed tolerance in preterm neonates?

Patent ductus arteriosus (PDA), especially PDA with sepsis, has been reported as a risk factor for feed intolerance in preterm neonates. In this study, the start to full feeds interval was found to be longest in preterm neonates (<or=28 weeks' gestation) with sepsis, followed by that in preterm neonates with sepsis and PDA, and in those with PDA alone.

Is surgical ligation of patent ductus arteriosus necessary? The Western Australian experience of conservative management

BACKGROUND

Surgical ligation of patent ductus arteriosus (PDA) is widely practised in preterm infants despite no clear evidence that this improves outcomes. Geographical isolation meant that ductal ligation was not an option in King Edward Memorial Hospital until recently.

OBJECTIVE

A retrospective data analysis to test the hypothesis that outcomes of infants with persistent PDA were no worse than those of infants with no significant duct or a duct that closed after medical treatment.

PATIENTS AND METHODS

A total of 252 infants (gestation < or =28 weeks) born between 1 January 2000 and 30 June 2002 were divided into three groups: group 1, no significant PDA (n = 154); group 2, significant PDA which closed after medical treatment (n = 65); group 3, significant PDA remaining patent after medical treatment (n = 33). A significant PDA was defined by a left atrium to aortic root ratio of >1.4 or a ductal diameter >1.5 mm with a left to right shunt.

RESULTS

Twenty four (10%) infants died at median (interquartile range) 15.5 (9-35) days. After adjustment for gestational age, relative to group 1, the infants from group 3 were at a 4.02 times increased risk of death (95% confidence interval 1.12 to 14.51). There was no significant difference between groups in the incidence of chronic lung disease, chronic lung disease or death, necrotising enterocolitis, intraventricular haemorrhage, duration of oxygen, or hospital stay.

CONCLUSION

Mortality was higher in infants with a persistent PDA, but other morbidities were not significantly different. A randomised trial is needed to determine whether surgical ligation will reduce mortality in such infants.

The biology of cortical granules

An egg-that took weeks to months to make in the adult-can be extraordinarily transformed within minutes during its fertilization. This review will focus on the molecular biology of the specialized secretory vesicles of fertilization, the cortical granules. We will discuss their role in the fertilization process, their contents, how they are made, and the molecular mechanisms that regulate their secretion at fertilization. This population of secretory vesicles has inherent interest for our understanding of the fertilization process. In addition, they have import because they enhance our understanding of the basic processes of secretory vesicle construction and regulation, since oocytes across species utilize this vesicle type. Here, we examine diverse animals in a comparative approach to help us understand how these vesicles function throughout phylogeny and to establish conserved themes of function.

Clozapine use in patients with schizophrenia and the risk of diabetes, hyperlipidemia, and hypertension: a claims-based approach

BACKGROUND

Numerous case reports have linked clozapine to the development of diabetes mellitus and hyperlipidemia in patients with schizophrenia. However, investigators have been unable to clearly demonstrate this association when compared with a control group receiving conventional antipsychotics.

METHODS

Medical and pharmacy claims from the Iowa Medicaid program were used to compare incidence rates for diabetes, hyperlipidemia, and hypertension in 552 patients receiving clozapine and 2461 patients receiving conventional antipsychotics (eg, haloperidol, chlorpromazine hydrochloride), with the use of a retrospective cohort design. Logistic regression was used to compare incidence rates adjusting for age, sex, and duration of available follow-up.

RESULTS

No significant differences in overall incidence rates for diabetes, hyperlipidemia, or hypertension were observed in patients receiving clozapine vs conventional antipsychotics. However, among younger patients (aged 20-34 years), clozapine administration was associated with a significantly increased relative risk of diabetes (2.5 [95% confidence interval, 1.2-5.4]) and hyperlipidemia (2.4 [95% confidence interval, 1.1-5.2]), but not hypertension (0.9 [95% confidence interval, 0.4-2.0]).

CONCLUSIONS

These data suggest that clozapine may not be an independent cause of diabetes or hyperlipidemia, but instead acts as an effect modifier in susceptible populations by increasing weight or affecting insulin secretion and resistance. This finding requires confirmation in other settings and patient populations and with the other atypical antipsychotics (risperidone, olanzapine, and quetiapine fumarate). The potential long-term medical and economic implications of the early induction of diabetes and hyperlipidemia in patients with schizophrenia warrant further study.

Trace contaminant concentrations in the Kara Sea and its adjacent rivers, Russia

Trace organic (chlorinated pesticides, PCBs, PAHs and dioxins/furans) and trace metal concentrations were measured in surficial sediment and biological tissues (i.e., worms, crustaceans, bivalve molluscs, and fish livers) collected from the Russian Arctic. Total DDT, chlordane, PCB and PAH concentrations ranged from ND to 1.2, ND to <0.1, ND to 1.5 and <20-810 ng g(-1), respectively, in a suite of 40 surficial sediment samples from the Kara Sea and the adjacent Ob and Yenisey Rivers. High sedimentary concentrations of contaminants were found in the lower part of the Yenisey River below the salt wedge. Total dioxins/furans were analysed in a subset of 20 sediment samples and ranged from 1.4 to 410 pg g(-1). The highest trace organic contaminant concentrations were found in organisms, particularly fish livers. Concentrations as high as 89 ng g(-1) chlordane; 1010 ng g(-1) total DDTs; 460 ng g(-1) total PCBs; and 1110 ng g(-1) total PAH, were detected. A subset of 11 tissue samples was analysed for dioxins and furans with total concentrations ranging from 12 to 61 pg g(-1). Concentrations of many trace organic and metal contaminants in the Kara Sea appear to originate from riverine sources and atmospheric transport from more temperate areas. Most organic contaminant concentrations in sediments were low; however, contaminants are being concentrated in organisms and may pose a health hazard for inhabitants of coastal villages.

Organic carbon flow in the Ob, Yenisey Rivers and Kara Sea of the Arctic region

Stable carbon isotope and elemental C/N ratios of the organic fraction of a set of samples along a transect in the Ob and Yenisey Rivers into the Kara Sea in the Arctic were measured. Previously, the concentrations of 239,240Pu and 137Cs in these same samples had been determined. The coupled measurements were carried out to assess possible connectivity between organic carbon flow into the Kara Sea and transport of radioactive nuclides in this marine environment. Organic carbon flow into the Kara Sea is influenced significantly by terrigenous sources carried by the Ob and Yenisey Rivers. The carbon isotope-organic carbon relationship provides evidence that a rich source of terrigenous carbon exists in the riverine system. A weak, but significant relationship between stable carbon isotope ratio and 137Cs suggests that most of the 137Cs is derived from riverine particles, as compared to Pu which is also derived from in situ scavenging within the water column.

The geographic distribution of population health and contaminant body burden in gulf of Mexico oysters

As part of NOAA's National Status and Trends Mussel Watch Program, oysters were sampled along the Gulf of Mexico coast each winter from 1986 to 1993 (The present analysis deals with 1986-1993 Mussel Watch data; the Mussel Watch project itself continues at this printing) and analyzed for trace metal, polynuclear aromatic hydrocarbons and pesticide body burden, plus a series of biological variables designed to assess population status and health. We identified contaminant and biological variables in which large-scale spatial processes played an important role in establishing population values by examining the likelihood that neighboring bays tended to have populations with body burdens or population attributes more similar than expected by chance. Local or watershed-dependent factors, such as land use and freshwater inflow, are important in controlling the bay-to-bay variation in body burden in most contaminants. However, the bay-to-bay variations in body burden of some metals (As, Cd, Hg, Ni, Se) appear to be principally influenced by larger-scale climatic factors. These metals and the biological variable shell length demonstrated a strong degree of similarity between bays over a large regional area reminiscent of the pattern shown by climatic factors, such as temperature and precipitation. In contrast, among the organics, none of the PAHs showed even a moderately strong climatic signal. Among the pesticides, only two did (dieldrin, total DDTs). These pesticides and the biological variables, reproductive stage and Perkinsus marinus prevalence and infection intensity, had spatial patterns that suggested both a local and a regional influence to their geographic distributions. This same pattern is exhibited by freshwater runoff. Metal contaminants also behaved distinctively compared to organics in the temporal influence of climate in establishing the interannual variability in body burden. For the organics, trends in interannual variability were strongly influenced by climate, whereas spatial trends were not. In contrast, most metals were unaffected by climatic forcing both spatially and temporally. However, all of the metals having a spatial pattern strongly influenced by climate (As, Cd, Hg, Ni, Se) also exhibited interannual variations related to variations in climate.

Ocean storage of nuclear wastes? Experiences from the Russian Arctic

An international demonstration (RD&D) project for ocean storage of radioactive wastes should be proposed, to study the feasibility of the concept of ocean storage of nuclear waste. This international project should utilize the scientific, engineering and technical capabilities of selected universities, oceanographic institutions, NGOs and industries. This project would need to be an independent (non-governmental) study, utilizing the capabilities of selected universities, oceanographic institutions, environmental NGOs (Non-Governmental Organizations) and industries. Scientists and engineers first need to conduct an engineering, environmental, and economic feasibility study of the concept. The goal of the project would be to determine if ocean-based storage reduced the risks to the environment and public health to a greater degree than land-based storage. This would require comparing the risks and factors involved and making the data and information available to anyone, anywhere, anytime on the internet. The mere presence of an investigation of the ocean storage option could facilitate scientific and engineering competition between the two options, could subsequently reduce environmental and public risks and provide better protection and cost benefits in the system utilized. One of the primary concerns of the scientific community would be related to the sensitivity and precision of the monitoring of individaul containers on the ocean bottom. An advantage of the land-based option is that if there is a release, its presence could be detected at very low levels and be contained in the storage facility. On the ocean bottom, a release from a container might not be easily detected due to dispersion. Therefore the containment system would have to be a system within a system with monitoring between the two providing greater protection. Ocean storage may have greater technical and political hurdles than land-based options, but it may provide greater protection over time, because it negates the threat of terrorism, it therefore merit further study. In the future if the use of nuclear energy and nuclear wastes increases, the global society could benefit from this international project, because it could reduce environmental and public health risks and promote energy independence.

Information gained from linking SEER Cancer Registry Data to state-level hospital discharge abstracts. Surveillance, Epidemiology, and End Results

OBJECTIVES

Our goal was to link patients from the Iowa Surveillance, Epidemiology, and End Results (SEER) Registry to their respective inpatient discharge abstracts from an Iowa Health Care Cost and Utilization Project (HCUP)-formatted database and evaluate whether this linkage provides information related to cancer treatment variation.

METHODS

Computer algorithms linked patients from the Iowa SEER Registry to discharge abstracts using 5 variables consistently defined between the databases (hospital identification, date of birth, admission date, discharge date, and zip code). Abstracts were reviewed for validity, and links not passing face validity were excluded.

SUBJECTS

Our sample contained 7,296 patients with early-stage breast cancer (I, IIa, IIb) with surgery from the Iowa SEER Registry from 1989 through 1994 with contacts only with Iowa hospitals.

RESULTS

Inpatient discharges abstracts were linked to 86.4% of the patients in our sample. More than 96% of the linked discharges for Medicare patients had a corresponding Medicare claim. Over 45% of the linked patients were not covered by Medicare. Comorbidity indexes were comparable to other published sources. Significant differences in diagnosis, comorbidities, and treatment were found across third-party payers.

CONCLUSIONS

This linkage provides a valuable source of comorbidity and insurance data and perhaps the only source of secondary clinical information for the uninsured. This linkage is best suited for cancers requiring inpatient stays for treatment and for those states where border crossing for treatment is low.

Direct molecular interaction of a conserved yolk granule protein in sea urchins

The regulation of yolk storage in oocytes and subsequent utilization in embryos is critical for embryogenesis. In sea urchins, the major yolk protein is made in the intestines, transported to the ovaries and accumulated in developing oocytes within membrane-bound vesicles comprising approximately 10% of the mass of an egg. Here, a non-yolk protein that accumulates specifically in yolk granules is reported. This protein was identified by cDNA cloning and, by use of antibodies to the recombinant protein, it was shown that this molecule is stored selectively in yolk granules of oocytes and embryos. No accumulation was seen in the accessory cells, testis, or intestines. In situ ribonucleic acid (RNA) hybridizations showed that the transcript accumulated only in oocytes, and was more highly concentrated in young oocytes. However, later in oogenesis, the messenger ribonucleic acid (mRNA) levels decreased significantly so that no signal was detectable in mature haploid eggs or at any later stage in development. However, by immunofluorescence and western blot analysis, the 30 kDa band was present throughout development. The predicted sequence of this protein shows that it is a member of the bep, HLC-32, EBP family of sea urchin proteins, but as it does not accumulate at the cell surface, nor in the hyaline layer in the two species studied here, as do other members of the family, it has been referred to as YP30 (30 kDa protein of the yolk platelet). To address its potential function, yeast two-hybrid analysis was performed to screen for proteins that potentially interact with YP30. It was found that it binds itself, and forms strongly interacting dimers. It is hypothesized that YP30 participates in the packaging and storage of major yolk protein during oogenesis, or in the utilization of the major yolk protein in development.

The marginal benefits of invasive treatments for acute myocardial infarction: does insurance coverage matter?

This paper applies instrumental variable (IV) techniques and estimates the average benefits of invasive surgical treatments for marginal acute myocardial infarction (AMI) patients by insurance coverage. The study uses data from the Agency for Healthcare Research and Quality's Healthcare Cost and Utilization Project (HCUP), State Inpatient Databases for the state of Washington, for years 1988-1993. We observed differences in average benefits for marginal patients across insurance subpopulations that cannot be explained by differences in measured clinical circumstances. Our empirical results show that the insurance subpopulations with the greatest estimated marginal benefits are those with the lowest expected payment generosity to providers. Because of the relatively weak explanatory power of our instruments for three insurance subpopulations, and because many of the parameter estimates across the insurance subpopulations are not statistically different from each other, policy recommendations should be approached cautiously. However, our application of IV techniques to AMI patients demonstrates the usefulness of this approach to estimate treatment effects across patient populations (e.g., across types of insurance coverage) for medical conditions of interest to policymakers. These estimates may help determine whether treatments are overutilized or underutilized.

Immunodominance among EBV-derived epitopes restricted by HLA-B27 does not correlate with epitope abundance in EBV-transformed B-lymphoblastoid cell lines

Using synthetic peptides, the HLA-B27-restricted CTL response to EBV in asymptomatic virus carriers has been mapped to four epitope regions in EBV latent cycle Ags. One of these peptide-defined epitopes (RRIYDLIEL) tends to be immunodominant and is recognized in the context of all three B27 subtypes studied, B*2702, B*2704, and B*2705. The other peptide-defined epitopes induce responses only in the context of one subtype, the immunogenic combinations being RRARSLSAERY/B*2702, RRRWRRLTV/B*2704, and FRKAQIQGL/B*2705. We used immunoaffinity chromatography to isolate the naturally presented viral peptides associated with these MHC class I molecules on the surface of EBV-transformed B-LCL. Using CTL reconstitution assays in conjunction with mass spectrometry, we established that the naturally processed and presented peptides are identical with the previously identified synthetic sequences. Despite the subtype-specific immunogenicity of three of the four epitopes, all four epitope peptides were found in association with each of the three different HLA-B27 subtypes. Indeed, those peptides that failed to induce a response in the context of a particular HLA-B27 subtype were frequently presented at greater abundance by that subtype than were the immunogenic peptides. Furthermore, among the peptides that did induce a response, immunodominance did not correlate with epitope abundance; in fact the immunodominant RRIYDLIEL epitope was least abundant, being present at less than one copy per cell. The relationship of this unexpected finding to the persistence of EBV is discussed.

Cytotoxic T-lymphocyte responses to a polymorphic Epstein-Barr virus epitope identify healthy carriers with coresident viral strains

Cytotoxic T-lymphocyte (CTL) responses to Epstein-Barr virus (EBV) tend to focus on a few immunodominant viral epitopes; where these epitope sequences are polymorphic between EBV strains, host CTL specificities should reflect the identity of the resident strain. In studying responses in HLA-B27-positive virus carriers, we identified 2 of 15 individuals who had strong CTL memory to the pan-B27 epitope RRIYDLIEL (RRIY) from nuclear antigen EBNA3C but whose endogenous EBV strain, isolated in vitro, encoded a variant sequence RKIYDLIEL (RKIY) which did not form stable complexes with B27 molecules and which was poorly recognized by RRIY-specific CTLs. To check if such individuals were also carrying an epitope-positive strain (either related to or distinct from the in vitro isolate), we screened DNA from freshly isolated peripheral blood mononuclear cells for amplifiable virus sequences across the EBNA3C epitope, across a different region of EBNA3C with type 1-type 2 sequence divergence, and across a polymorphic region of EBNA1. This showed that one of the unexplained RRIY responders carried two distinct type 1 strains, one with an RKIY and one with an RRIY epitope sequence. The other responder carried an RKIY-positive type 1 strain and a type 2 virus whose epitope sequence of RRIFDLIEL was antigenically cross-reactive with RRIY. Of 15 EBV-seropositive donors analyzed by such assays, 12 appeared to be carrying a single virus strain, one was coinfected with distinct type 1 strains, and two were carrying both type 1 and type 2 viruses. This implies that a small but significant percentage of healthy virus carriers harbor multiple, perhaps sequentially acquired, EBV strains.

Market factors and the availability of community pharmacies

The purpose of this study was to examine the relationships between the availability of community pharmacies and 4 types of market factors. A composite data set was created that linked, at the county level, data on: (1) type and number of pharmacies; (2) population characteristics; (3) payer variables; (4) health care system factors; and (5) competitive factors. In this exploratory study, secondary data were used to assess the association between the availability of community pharmacies and the influence of market factors. To assess the market influences on availability of community pharmacies, 2 regressions were performed. In 1 model, the number of community pharmacies per 10,000 population was the dependent variable, whereas the dependent variable in the other regression was the proportion of independently owned community pharmacies. The independent variables in each regression were the market factors--population characteristics, payer variables, health care system factors, and competitive variables. Squared terms were included for 8 of 15 market factors to account for nonlinearities in the relationships. Multiple market factors were correlated with both the number of community pharmacies and the proportion of independently owned pharmacies in an area. Several of the relationships were not linear and changed direction within the range of data. Counties with either a low or a high percentage of elderly people had fewer pharmacies and a lower proportion of independently owned pharmacies compared with counties with a moderate percentage of elderly people. Counties that were scarcely or highly rural had fewer community pharmacies but a higher proportion of independently owned pharmacies than counties that were moderately rural. Areas with a greater percentage of the population earning less than the poverty level had more pharmacies, especially independently owned ones. Fewer community pharmacies were found in areas with higher health maintenance organization penetration rates. The number of hospital admissions was positively associated with the number of pharmacies but negatively associated with the proportion of independently owned pharmacies. The availability of community pharmacies varies across the country. In light of the trend toward fewer independently owned pharmacies, potential problems in accessing pharmacy services could develop in certain areas, including those that are highly rural and those with a high percentage of people earning less than the poverty level. Future research and policy issues are identified.

Injuries in water polo

Water polo is the only true "contact" sport of the aquatic disciplines. This article deals with the most common, aggressive, acute injuries, and the repetitive, overuse strains and sprains facing any athlete. Research to date demonstrates that the combination of swimming and throwing (without the benefit of a firm base of support) places a unique demand on the water polo athlete. The shoulder continues to be the most recognized and studied area of injury, with lacerations and traumatic fractures of the face and hand the next most prevalent. The premiere of women's water polo in the Sydney (Australia) 2000 Olympic games will draw more attention to this exciting, challenging sport.

Factors affecting bargaining outcomes between pharmacies and insurers

OBJECTIVE

To model the bargaining power of pharmacies and insurers in price negotiations and test whether it varies with characteristics of the pharmacy, insurer, and pharmacy market.

DATA SOURCES/STUDY SETTING

Data from four sources. Pharmacy/insurer transactions were taken from Medstat's universe of 6.8 million pharmacy claims in their 1994 Marketscan database. Sources Informatics, Inc. supplied a three-digit zip code-level summary database containing pharmacy payments and self-reported costs for retail (cash-paying) customers for the top 200 pharmaceutical products by prescription size in 1994. The National Council of Prescription Drug Programs supplied their 1994 pharmacy database. Zip code-level socioeconomic and commercial information was taken from Bureau of the Census' 1990 Summary Tape File 3B and 1994 Zip Code Business Patterns database.

STUDY DESIGN

The provider/insurer bargaining model first employed in Brooks, Dor, and Wong (1997, 1998) was adapted to the circumstances surrounding pharmacy and insurer bargaining.

DATA COLLECTION/EXTRACTION METHODS

The units of observation in this study were single Medstat claims for each unique insurer/pharmacy combination in the database for selected pharmaceutical products. The four products selected varied in the conditions they treat, whether they are used to treat chronic or acute conditions, and by their sales volume. Used in the analysis were 9,758 Zantac, 2,681 Humulin, 3,437 Mevacor, and 1,860 Dilantin observations.

PRINCIPAL FINDINGS

We find statistically significant variation in pharmacy bargaining power. Pharmacy bargaining power varies significantly across markets, insurers, and pharmacy types. With respect to market structure, pharmacy bargaining power is negatively related to pharmacies per capita and pharmacies per employer and positively related to pharmacy concentration at higher concentration levels. In addition, the higher the percentage of independent pharmacies in an area, the lower the pharmacy bargaining power. With respect to socioeconomic conditions, pharmacy bargaining power is higher in areas with lower per capita income and higher rates of public assistance.

CONCLUSIONS

The bargaining power of pharmacies in contract negotiations with insurers varies considerably with exogenous factors. Local area pharmacy ownership concentration enhances pharmacy bargaining. As a result, anti-trust law prohibiting the collective bargaining of independent pharmacies with insurers leaves independents at a disadvantage with respect to chains.

Varying health care provider objectives and cost-shifting: the case of retail pharmacy in the US

In this paper we investigate the relationship between health care provider objectives, cost-shifting, and prices by exploring the relationship between state Medicaid pharmacy reimbursements and average prices paid by pharmacy retail customers for four distinct pharmaceutical products across the US in 1994. We develop a more general theory than past researchers to enable provider objectives to vary with Medicaid pharmacy reimbursement levels. We find that provider objectives and the direction of relationship between Medicaid pharmacy reimbursements and retail prices vary with Medicaid pharmacy reimbursement levels. At high Medicaid pharmacy reimbursement levels we find a consistent negative relationship across products. At low Medicaid pharmacy reimbursement levels, the direction of the relationship is product-specific. As a result, policy-makers should be aware that policies affecting reimbursements from government-sponsored health insurance will also affect retail customers that include the uninsured. Paradoxically, for certain products if a state cuts a generous Medicaid reimbursement level this could hurt uninsured patients, whereas cuts in a stingy Medicaid reimbursement rate may help uninsured patients.

HLA-B27 subtype polymorphism and CTL epitope choice: studies with EBV peptides link immunogenicity with stability of the B27:peptide complex

HLA-B27-restricted CTL responses to EBV are principally directed against two of the EBV nuclear Ags, EBNAs 3B and 3C. We have previously described a target epitope derived from EBNA 3C (residues 258-266, sequence RRIYDLIEL) that is immunodominant in the context of at least three different B27 subtypes, including B*2705 and B*2702. In this study, we show that this peptide binds well to B*2705 and B*2702 in a cell surface binding assay, and that the two B27:peptide complexes are relatively stable, with t1/2 of 20 and 37 h, respectively. We now identify another B27-restricted epitope derived from EBNA 3B (residues 243-253, sequence RRARSLSAERY), which again accords well with the B*2705/B*2702 consensus motifs, having an arginine residue at position 2 and a tyrosine residue at the carboxyl terminus. In this case, five of five B*2702-positive donors respond to the epitope, whereas there was no response in any B*2705-positive donor studied. This peptide binds at least as well to B*2705 as to its restriction element B*2702; however, the two class I:peptide complexes show marked differences in stability, with t1/2 of 9 and 42 h, respectively. Thus, the stability of B27:peptide complexes can vary markedly between different B27 subtypes in ways that may not be apparent from cell surface binding assays and cannot be predicted from currently known peptide consensus motifs, yet which may critically influence CTL epitope choice.

Relationship between peptide binding and T cell epitope selection: a study with subtypes of HLA-B27

The effect of HLA-B27 polymorphism on antigen presentation was analysed by comparing the binding of three Epstein-Barr virus-derived peptide epitopes to HLA-B27 subtypes with their immunogenicity and antigenicity in the context of these subtypes. The effect of altering the major anchor residue Arg2 on binding or on recognition by peptide-specific cytotoxic T lymphocytes (CTL) was also examined. The three peptides bound significantly to all the B*2701-B*2706 subtypes. This did not correlate with the peptides being immunogenic or recognized by specific CTL in the context of only particular subtypes. In addition, of the three viral epitopes tested, those that were immunogenic in B*2702- or B*2705-restricted responses bound to these subtypes less efficiently than one peptide that was immunogenic only in the B*2704 context. Thus, among several potentially immunogenic peptides from the same virus, the antiviral response is not necessarily directed against the one that binds best to the restricting subtype. These results indicate that HLA-B27 polymorphism influences antigen presentation in ways other than simply peptide affinity. Synthetic analogues lacking the canonical Arg2 motif of HLA-B27-bound peptides, even when binding much worse to the restricting subtype, were recognized equally by CTL specific for the parental peptide. This indicates that Arg2 is not required to maintain the structure of the epitope. The implications of these results for pathogenetic models of HLA-B27-associated disease are discussed.

Hospital-insurer bargaining: an empirical investigation of appendectomy pricing

Employers' increased sensitivity to health care costs has forced insurers to seek ways to lower costs through effective bargaining with providers. What factors determine the prices negotiated between hospitals and insurers? The hospital-insurer interaction is captured in the context of a bargaining model, in which the gains from bargaining are explicitly defined. Appendectomy was chosen because it is a well-defined procedure with little clinical variation. Our results show that certain hospital institutional arrangements (e.g. hospital affiliations), HMO penetration, and greater hospital concentration improve hospitals' bargaining position. Furthermore, hospitals' bargaining effectiveness has diminished over time and varies across states.

Conserved CTL epitopes within EBV latent membrane protein 2: a potential target for CTL-based tumor therapy

In healthy virus carriers, EBV is subject to strong CTL responses that principally target the EBV nuclear Ag (EBNA) 3A, 3B, 3C subset of virus proteins. In vitro-reactivated CTLs of this kind have proved very effective in treating EBV-positive immunoblastic lymphoma, a malignancy that expresses the full range of virus proteins. However, targeting other EBV-positive tumors will require CTLs that recognize some of the subdominant viral Ags since in nasopharyngeal carcinoma and EBV-positive Hodgkin's disease, EBNA1, latent membrane protein (LMP) 1, and LMP2 are the only virus proteins present. Studying healthy virus carriers (Caucasian and Chinese), we identified five CTL target epitopes in LMP2 restricted through HLA alleles particularly common in the southern Chinese population, which is most at risk for nasopharyngeal carcinoma (HLA-A2, 50%; A11, 50%; A24, 30%; and B40, 32%). Furthermore, we analyzed the effect of HLA subtype polymorphism, especially in the context of A2 for which four subtypes are present at significant frequency in the Chinese population. As to virus polymorphism, LMP2 epitope sequences (in contrast to EBNA 3A, 3B, and 3C epitopes) were shown to be antigenically conserved among EBV isolates from different world populations, including viruses present in nasopharyngeal carcinoma and Hodgkin's disease biopsy samples. Thus, nasopharyngeal carcinoma and Hodgkin's disease are predicted to express LMP2 proteins that contain conserved CTL target epitopes restricted through common HLA alleles; boosting responses to these epitopes could form the basis of a CTL-based therapy for these malignancies.

Conserved CTL epitopes within EBV latent membrane protein 2: a potential target for CTL-based tumor therapy

In healthy virus carriers, EBV is subject to strong CTL responses that principally target the EBV nuclear Ag (EBNA) 3A, 3B, 3C subset of virus proteins. In vitro-reactivated CTLs of this kind have proved very effective in treating EBV-positive immunoblastic lymphoma, a malignancy that expresses the full range of virus proteins. However, targeting other EBV-positive tumors will require CTLs that recognize some of the subdominant viral Ags since in nasopharyngeal carcinoma and EBV-positive Hodgkin's disease, EBNA1, latent membrane protein (LMP) 1, and LMP2 are the only virus proteins present. Studying healthy virus carriers (Caucasian and Chinese), we identified five CTL target epitopes in LMP2 restricted through HLA alleles particularly common in the southern Chinese population, which is most at risk for nasopharyngeal carcinoma (HLA-A2, 50%; A11, 50%; A24, 30%; and B40, 32%). Furthermore, we analyzed the effect of HLA subtype polymorphism, especially in the context of A2 for which four subtypes are present at significant frequency in the Chinese population. As to virus polymorphism, LMP2 epitope sequences (in contrast to EBNA 3A, 3B, and 3C epitopes) were shown to be antigenically conserved among EBV isolates from different world populations, including viruses present in nasopharyngeal carcinoma and Hodgkin's disease biopsy samples. Thus, nasopharyngeal carcinoma and Hodgkin's disease are predicted to express LMP2 proteins that contain conserved CTL target epitopes restricted through common HLA alleles; boosting responses to these epitopes could form the basis of a CTL-based therapy for these malignancies.

NIST SRM 1945, whale blubber, NIST SRM 1974a, organics in mussel tissue, and NIST SRM 1941a, organics in marine sediment as certified reference materials for polychlorinated dioxins and furans in marine ecosystems

Few natural matrix Standard Reference Materials are available for the validation of analytical methods measuring polychlorinated dioxins and furans (PCDDs and PCDFs) in marine ecosystems. The concentrations of PCDDs and PCDFs in NIST SRM 1945, SRM 1974a, and SRM 1941a are of interest because the analysis of marine mammal, mussel tissues and sediments have become important tools in the determination of organochlorine contamination of the environment. Because these SRMs have been demonstrated to be homogenous for other organic contaminants, they would be expected to be reliable standards for validation of polychlorinated dioxins and furans in marine mammals, mussels and sediments as well.

18S rRNA data indicate that Aschelminthes are polyphyletic in origin and consist of at least three distinct clades

The Aschelminthes is a collection of at least eight animal phyla, historically grouped together because the absence of a true body cavity was perceived as a pseudocoelom. Analyses of 18S rRNA sequences from six Aschelminth phyla (including four previously unpublished sequences) support polyphyly for the Aschelminthes. At least three distinct groups of Aschelminthes were detected: the Priapulida among the protostomes, the Rotifera-Acanthocephala as a sister group to the protostomes, and the Nematoda as a basal group to the triploblastic Eumetazoa.

Effect of production environment on labor demand in Veterans Affairs medical center pharmacies

The relationship between pharmacy production environment and labor-time requirements was estimated by using data from Veterans Affairs medical center (VAMC) pharmacies. Economic theory was used to derive equations for estimating labor-time requirements for pharmacy services that take into account differences in production environment (factors that cannot be controlled by the pharmacy manager within a given observation period, such as pharmacy service mix and distance to patient care wards). The equations were estimated by using information obtained from the Department of Veterans Affairs (VA) and from a mail survey of VAMC pharmacy chiefs. The resulting estimates of labor-time requirements were compared with pharmacy labor-time requirements produced by the VA in 1989. Labor-time requirements varied dramatically with production environment, and the labor-time requirements calculated in this study generally exceeded those used by the VA. Accurate forecasts of required pharmacist and technician labor time must take into account the production environment within each pharmacy.

Analysis of Gulf of Mexico bottlenose dolphins for organochlorine pesticides and PCBs

Organochlorine concentrations were determined in blubber samples from 33 Tursiops truncatus stranded on the Texas and Florida coastlines. All tissues had measurable concentrations of 4,4'-DDE (0.18-70.7 microg/g lipid weight) and SigmaPCB (4.1-149 microg/g lipid weight). Pesticide and PCB concentrations were similar to those reported in Tursiops truncatus from the Atlantic coast of the United States and the southeast coast of Africa. Organochlorine concentrations were highest in mature males, and differences in the SigmaPCB/SigmaDDT ratios between mature and immature males suggests a recent decrease in DDT uptake, related to the commercial DDT ban in the US in 1971, as well as dietary differences between younger and older animals. Analysis of a female and her calf indicate that females reduce their own organochlorine body burden through transplacental transfer. However, no reduction of some higher molecular weight PCBs was found. Transplacental transfer rates of 5.1% for SigmaDDT and 3.7% for SigmaPCB were determined based on a stranded female and her full term, unborn calf. Predictions of uptake and depuration rates of organochlorines based on gender in Tursiops truncatus agree with clearance rates from previous studies.

An absent ophthalmic artery or carotid siphon signal on transcranial Doppler confirms the presence of severe ipsilateral internal carotid artery disease

Transcranial Doppler ultrasound provides a useful adjunct to extracranial ultrasound in the diagnosis of carotid bifurcation disease. Previous studies have shown that collateral flow patterns and diminished flow velocities in the ipsilateral middle cerebral artery correlate with hemodynamically significant carotid disease. In a series of 7,054 carotid duplex and transcranial Doppler examinations, 12.5% (95% confidence interval [CI]: 8.7, 16.4) of 287 ophthalmic arteries ipsilateral to an apparent carotid occlusion had no detectable flow signal, compared with 0.5% (95% CI: 0.3, 0.7) of 6,767 ophthalmic arteries ipsilateral to a non-occluded carotid artery (p < 0.001). Carotid siphon signals were not detectable in 24.4% (95% CI: 19.4, 29.4) of arteries ipsilateral to the carotid occlusion, versus 1.0% (95% CI: 0.8, 1.3) ipsilateral to nonoccluded carotid arteries (p < 0.001). A significant number of absent ophthalmic artery and carotid siphon signals (5.7 and 8.7%, respectively) were also found in patients with 80 to 99% extracranial carotid stenosis. A subset of 216 studies with angiographic correlation confirmed the high association of these transcranial Doppler findings with severe stenosis or occlusion of the internal carotid artery. Primary ophthalmological disease or siphon occlusion did not explain these findings. An absent ophthalmic artery or carotid siphon signal on transcranial Doppler examination is believed to represent a failure to detect slow flow distal to severe carotid bifurcation lesions. As a sign of ipsilateral carotid occlusion, the sensitivities of absent ophthalmic artery and carotid siphon signals are quite low (12.5 and 24.4%, respectively). The high specificities of 99.5 and 99.0%, however, make these findings useful in confirming the diagnosis of presumptive carotid occlusion by carotid duplex ultrasound.

Polynuclear aromatic hydrocarbon contaminants in oysters from the Gulf of Mexico (1986-1990)

Polynuclear aromatic hydrocarbon (PAH) contaminant concentrations in 870 composite oyster samples from coastal and estuarine areas of the Gulf of Mexico analyzed as part of National Oceanographic and Atmospheric Administration's (NOAA's) National Status and Trends (NS&T) Mussel Watch Program exhibit a log-normal distribution. There are two major populations in the data. The cumulative frequency function was used to deconvolute the data distribution into two probability density functions and calculate summary statistics for each population. The first population consists of sites with lower PAH concentration probably due to background contamination (i.e. stormwater runoff, atmospheric deposition). The second population are sites with higher concentrations of PAHs associated with local point sources of PAH input (i.e. small oil spills, etc.). The temporal pattern for the mean concentration of the populations from the Gulf of Mexico is consistent with large-scale climatic factors such as the El Niño cycles which affect the precipitation regime.

Factors associated with early presentation of acute stroke

BACKGROUND AND PURPOSE

Patients with stroke symptoms commonly delay many hours before seeking medical attention. We sought to explore the factors associated with early presentation of stroke patients to physicians.

METHODS

We prospectively studied 100 consecutive acute stroke patients presenting to three large, urban medical centers. Using a standardized, structured interview and chart review, we assessed patient education about stroke, risk factors, clinical features of the stroke, source of stroke recognition, and timing of presentation. We did not study the distance from the site of stroke onset to the site of physician contact.

RESULTS

Stroke onset time was known in 96 of the patients. Mean patient age was 71.3 years, 79% had at least one stroke risk factor, 26% had prior transient ischemic attack, 19% had prior stroke, 74% had some high school education, and 86% had regular physicians. Only 8% had been previously educated about stroke symptoms. Eighty one percent of strokes were ischemic. The mean time to physician contact was 13.4 +/- 2.3 hours (median, 4.0 hours) and to neurologist contact was 21.2 +/- 2.9 hours. A skewed distribution of presentation times accounts for the mean-median differences. A small number of patients presenting very late could have an effect on the correlations between presentation time and the variables studied. Early presentation time was associated with increased age, the sudden onset of a stable deficit, and recognition that the symptoms signified stroke. Only the sudden onset of a stable deficit correlated independently with early presentation time (P = .0048). There was no correlation between presentation time and prior transient ischemic attack or stroke, headache, vomiting, loss of consciousness or seizures at onset, or stroke subtype, but a type II error could not be excluded.

CONCLUSIONS

Despite their education level, regular health care, and risk factors, especially prior stroke and transient ischemic attack, these patients were not knowledgeable about stroke and delayed many hours before contacting physicians. The course of symptoms and recognition that they signified stroke were associated with earlier presentation. Patient education focused on groups at risk may hasten the presentation and treatment of acute stroke.

Different HLA-B27 subtypes present the same immunodominant Epstein-Barr virus peptide

An immunological basis has been postulated for the strong association between at least five subtypes of the HLA-B27 allele (B27.01, .02, .04, .05, and .06) and ankylosing spondylitis, namely that cytotoxic T lymphocyte (CTL) responses are induced against an "arthritogenic" peptide that these different subtypes can all present. This requires a degree of overlap between the peptide binding repertoires of different B27 molecules. The present work, using CTL responses to Epstein-Barr virus (EBV) as a model system in which to identify B27-restricted epitopes, provides the first direct evidence that different disease-related alleles can present the same immunodominant peptide. We first noted that EBV-specific CTL clones, whether from B27.05-, B27.02-, or B27.04-positive donors, were largely subtype-specific in their restriction, recognizing only EBV-transformed B cell lines of the relevant B27 subtype. However, when tested against targets expressing individual EBV proteins from recombinant vaccinia virus vectors, all B27.05-restricted, all B27.02-restricted, and a proportion of B27.04-restricted clones were reactive to the same viral nuclear antigen, Epstein-Barr nuclear antigen (EBNA)3C. In subsequent peptide sensitization assays, all the EBNA3C-specific clones tested and also the EBNA3C-specific component within polyclonal CTL preparations from B27.05-, B27.02-, or B27.04-positive donors recognized the same immunodominant viral peptide RRIYDLIEL (EBNA3C residues 258-266). This sequence accords well with the proposed B27.05 peptide motif and clearly must be accommodated within the different peptide binding grooves of B27.05, B27.02, and B27.04 molecules. Clonal analysis revealed a second component of the B27.04-restricted response that was not shared with other subtypes. This was directed against an EBV latent membrane protein LMP2 epitope whose sequence RRRWRRLTV satisfies some but not all requirements of the B27.05 peptide motif. We conclude that there is indeed a degree of functional overlap between different B27 subtypes in their selection and presentation of CTL epitopes.

The clinical utility of transcranial Doppler ultrasound in suspected vertebrobasilar ischemia

The impact of transcranial Doppler ultrasound (TCD) on the management of 107 consecutively referred patients with suspected vertebrobasilar ischemia was studied. Physicians who referred patients for TCD of the posterior circulation were interviewed before and after being given the results of the TCD examination. Management plans devised prior to knowledge of the TCD results were compared to those devised after TCD results were given. Management changed in 42% of the patients after TCD results were given, and there was a 58% reduction in the use of angiography (p = 0.04) and a 128% increase in the use of aspirin (p = 0.005). Changes in the use of anticoagulants and other diagnostic or therapeutic approaches were not significant. TCD appears to have a significant impact on the management of patients with suspected vertebrobasilar ischemia.

National status and trends mussel watch program: chlordane-related compounds in Gulf of Mexico oysters, 1986-1990

The National Oceanic and Atmospheric Administration's National Status and Trends (NS&T) Program has been monitoring the chemical contamination in bivalve tissues from the US coastal waters since 1986. alpha-Chlordane, trans-nonachlor, heptachlor and heptachlor epoxide, components of technical chlordane, are among the chlorinated pesticides measured. The geographical distribution of these chlordane compounds in oyster samples from the US Gulf of Mexico is well-established. For example, highest residue levels, predominantly alpha-chlordane and trans-nonachlor, were encountered in samples collected near highly populated areas in contrast with the concentrations measured in predominantly agricultural areas. Data collected during 5 years of bivalve sampling are used to evaluate temporal trends in residue concentrations at most NS&T sites. Minor decreases can be observed in the concentrations of alpha-chlordane and trans-nonachlor. Heptachlor and its epoxide concentrations, in contrast, have been increasing since 1987.

Butyltin concentrations in oysters from the Gulf of Mexico from 1989 to 1991

Oyster samples from 53 Gulf of Mexico coastal sites were collected and analyzed for butyltins during 1989, 1990, and 1991. The geometric-mean tributylin concentrations were 85, 30, and 43 ng Sn/g for 1989, 1990, and 1991, respectively. The tributyltin concentrations are best represented by a log-normal distribution. A decline in the butyltin concentrations at sites with relatively low butyltin concentrations for 1989 compared with 1990 and 1991 was observed, and, at relatively high butyltin concentrations (> 400 ng Sn/g), there was hardly any difference between 1989 and 1991, but lower concentrations were present in 1990. Continued monitoring is needed in order to determine if butyltin contamination of the coastal marine environment is decreasing in response to use limitations.

Identification of target antigens for the human cytotoxic T cell response to Epstein-Barr virus (EBV): implications for the immune control of EBV-positive malignancies

Epstein-Barr virus (EBV), a human herpes virus with oncogenic potential, persists in B lymphoid tissues and is controlled by virus-specific cytotoxic T lymphocyte (CTL) surveillance. On reactivation in vitro, these CTLs recognize EBV-transformed lymphoblastoid cell lines (LCLs) in an HLA class I antigen-restricted fashion, but the viral antigens providing target epitopes for such recognition remain largely undefined. Here we have tested EBV-induced polyclonal CTL preparations from 16 virus-immune donors on appropriate fibroblast targets in which the eight EBV latent proteins normally found in LCLs (Epstein-Barr nuclear antigen [EBNA] 1, 2, 3A, 3B, 3C, leader protein [LP], and latent membrane protein [LMP] 1 and 2) have been expressed individually from recombinant vaccinia virus vectors. Most donors gave multicomponent responses with two or more separate reactivities against different viral antigens. Although precise target antigen choice was clearly influenced by the donor's HLA class I type, a subset of latent proteins, namely EBNA 3A, 3B, and 3C, provided the dominant targets on a range of HLA backgrounds; thus, 15 of 16 donors gave CTL responses that contained reactivities to one or more proteins of this subset. Examples of responses to other latent proteins, namely LMP 2 and EBNA 2, were detected through specific HLA determinants, but we did not observe reactivities to EBNA 1, EBNA LP, or LMP 1. The bulk polyclonal CTL response in one donor, and components of that response in others, did not map to any of the known latent proteins, suggesting that other viral target antigens remain to be identified. This work has important implications for CTL control over EBV-positive malignancies where virus gene expression is often limited to specific subsets of latent proteins.

Chemosynthetic Mussels at a Brine-Filled Pockmark in the Northern Gulf of Mexico

A large (540 square meters) bed of Bathymodiolus n. sp. (Mytilidae: Bivalvia) rings a pool of hypersaline (121.35 practical salinity units) brine at a water depth of 650 meters on the continental slope south of Louisiana. The anoxic brine (dissolved oxygen </=0.17 milliliters per liter) contains high concentrations of methane, which nourishes methanotrophic symbionts in the mussels. The brine, which originates from a salt-cored diapir that penetrates to within 500 meters ofthe sea floor, fills a depression that was evidently excavated by escaping gas. The spatial continuity of the mussel bed indicates that the brine level has remained fairly constant; however, demographic differences between the inner and outer parts of the bed record small fluctuations.

Human cytotoxic T-cell responses against Epstein-Barr virus nuclear antigens demonstrated by using recombinant vaccinia viruses

The potentially pathogenic effects of infection with Epstein-Barr virus (EBV), a B-lymphotropic agent with cell growth-transforming potential, are contained in healthy virus carriers by virus-specific cytotoxic T-lymphocyte (CTL) surveillance. The target antigens against which such CTL responses are directed are yet undefined, but the antigens probably derived from one or more of the EBV "latent" proteins constitutively expressed in virus-transformed B cells. We have analyzed target specificity of CTL responses from two EBV-immune donors that are preferentially reactive against autologous cells transformed with type A but not with type B virus isolates. Coding sequences for four EBV latent proteins with allelic polymorphism between A and B virus types--namely, the EBV nuclear antigens (EBNAs) EBNA 2, EBNA 3a, EBNA 3c, and EBNA leader protein--have been introduced into vaccinia virus vectors under control of vaccinia promoter P7.5 and used to express relevant EBNA proteins in appropriate target cells. Thus the CTL response from one donor has been mapped to type A EBNA 2 protein and from a second donor to type A EBNA 3a protein. Thereafter, a series of recombinant vaccinia viruses were constructed that carried specific internal deletions within the EBNA 2 type A coding sequence; by using these vectors, the above EBNA 2 type A-specific CTL response was shown to be directed against an epitope within a 100-amino acid fragment near the N terminus of the protein. This work clearly shows human CTL recognition of virus-coded nuclear antigens in the EBV system; moreover, it establishes an experimental approach that can be extended to all EBV latent proteins and to the more common CTL responses that cross-react against type A and type B virus isolates.