Biomedical subjects

J Burger

Publications and source records attributed to J Burger.

At least 55 records · Page 3Linked to original sources

PubMed2000

A few comments on electrostatic interactions in cell physiology.

The role of fixed charges present at the surface of biological membranes is usually described by the Gouy-Chapman-Grahame theory of the electric double-layer where the Grahame equation is applied independently on each side of the membrane and where the capacitive charges (linked to the transmembrane ionic currents) are disregarded. In this article, we generalize the Gouy-Chapman-Grahame theory by taking into account both intrinsic charges (resulting from the dissociation of membrane constituents) and capacitive charges, in the density value of the membrane surface charges. In the first part, we show that capacitive charges couple electrostatic potentials present on both sides of the membrane. The intensity of this coupling depends both on the value of the membrane specific capacitance and the transmembrane electric potential difference. In the second part, we suggest some physiological implications of membrane electric double-layers.

Ion Channels↗

PubMed2000

Palaeogenetic analysis of (pre)historic artifacts and its significance for anthropology.

The possibility of isolating ancient DNA (aDNA) from all kinds of (pre)historic anthropogenetic artifacts opens new perspectives. This study applies palaeogenetic techniques to three anthropological issues: 1. Palaeodiet. DNA sequences from organic residues in vessels identify Precolumbian Aztec diet. 2. (Pre)historic husbandry and economic structures. aDNA data can reveal the species and the genetic evolutionary stage of animals and plants and show the manner and the extent of their growth, cultivation, or domestication. 3. Production techniques, use, and functionality. Identification of the plant or animal source of an archaeological find can reveal the use or the function of the find. Examples from a Celtic "sausage-end" and an Aztec "eye salve" are given.

Archaeology↗

PubMed2000

Metals and metallothionein in the liver of raccoons: utility for environmental assessment and monitoring.

The relationship between metallothionein levels and concentrations of several metals and radionuclides was examined in liver tissues of raccoons (Procyon lotor, n = 47) from the Department of Energy's Savannah River Site in South Carolina to determine the applicability of metallothioneins as an initial screening device for exposure assessment in free-living mammals and environmental monitoring. Using a fluorescent marker and a cell sorter to measure metallothionein, a significant positive correlation was found across animals between levels of metallothioneins and concentrations of selenium (Pearson's r = .30), mercury (Pearson's r = .3 1), and copper (Pearson's r = .30) in liver tissue. Arsenic, cobalt, silver, thallium, and tin were below detection limits in most or all liver samples. Other metals, including cadmium, chromium, radiocesium (137-Cs), copper, lead, manganese, strontium, and vanadium, showed only weak and nonsignificant correlations with metallothionein. Concentrations of mercury were correlated with concentrations of selenium (Pearson's r = .73), manganese (Pearson's r = .56), and strontium (Pearson's r = .57). In an a posteriori test, there was a still unexplained positive correlation between mercury (Pearson r = .56), selenium (Pearson r = .54), and radiocesium (Pearson's r = .38) concentrations and background cellular autofluorescence, and a negative correlation of strontium with the latter (Kendall tau = -.38). Background cellular autofluorescence may represent a generalized cellular stress response, or a yet unidentified biomarker. To better understand which metals contribute to the induction of metallothionein, principle component analysis (PCA) was performed. The first three principle components explained 78% of the variance, with highest loadings being from mercury and radiocesium. Metallothionein levels did not correlate well with the principal components from the metals and radiocesium, while autofluorescent background levels tended to correlate better.

Animals↗

PubMed1999

Corticosterone and growth hormone levels in shorebirds during spring and fall migration stopover.

Large numbers of shorebirds stop over at Delaware Bay during spring migration and undergo major mass increases within a two- to three-week period. We studied plasma levels of corticosterone and growth hormone in three species of migrants that use this site, sanderlings, Calidris alba, semipalmated plovers, Charadrius semipalmatus, and semipalmated sandpipers, Calidris pusilla. Semipalmated sandpipers were also studied at a fall migration stopover in Manomet, Massachusetts. These two hormones were chosen because they modulate the physiological processes of lipogenesis/lipolysis and promote increased feeding in birds. The stress response was not suppressed in the shorebirds studied, and plasma levels of corticosterone were elevated compared to other studies. We believe that the high levels of corticosterone relate to the rapid fat deposition that takes place at this stop-over site. There was a significant negative correlation between plasma growth hormone and body mass, indicating the lipolytic effects of the growth hormone. Because the lighter birds are recent arrivals to Delaware Bay they may have elevated plasma growth because of fat breakdown during flight to this stop-over site. High levels of growth hormone may also result in protein synthesis, replenishing tissues broken down during the previous migratory bout. J. Exp. Zool. 284:645-651, 1999.

Animals↗

PubMed1999

Resources and estuarine health: perceptions of elected officials and recreational fishers.

It is important to understand the perceptions of user groups regarding both the health of our estuaries and environmental problems requiring management. Recreational fishers were interviewed to determine the perceptions of one of the traditional user groups of Barnegat Bay (New Jersey), and elected officials were interviewed to determine if the people charged with making decisions about environmental issues in the bay held similar perceptions. Although relative ratings were similar, there were significant differences in perceptions of the severity of environmental problems, and for the most part, public officials thought the problems were more severe than did the fishers. Personal watercraft (often called Jet Skis) were rated as the most severe problem, followed by chemical pollution, junk, overfishing, street runoff, and boat oil. Small boats, sailboats, wind surfers, and foraging birds were not considered environmental problems by either elected officials or fishermen. The disconnect between the perceptions of the recreational fishers and those of the locally elected public officials suggests that officials may be hearing from some of the more vocal people about problems, rather than from the typical fishers. Both groups felt there were decreases in some of the resources in the bay; over 50% felt the number of fish and crabs had declined, the size of fish and crabs had declined, and the number of turtles had declined. Among recreational fishers, there were almost no differences in perceptions of the severity of environmental problems or in changes in the bay. The problems that were rated the most severe were personal watercraft and overfishing by commercial fishers. Recreational fishers ranked sailboats, wind surfers, and fishing by birds as posing no problem for the bay. Most fishers felt there had been recent major changes in Barnegat Bay, with there now being fewer and smaller fish, fewer and smaller crabs, and fewer turtles. The results suggest that the views of a wide range of coastal users should be considered when making environmental health decisions.

Adult↗

PubMed1999

Perceptions of on-site hunters: environmental concerns, future land use, and cleanup options at the Savannah river site.

The Department of Energy owns land in 34 states, and most of these lands have been off limits to the public for over 50 years. Although some parts of each site are contaminated, most of many sites are not. With the ending of the Cold War, the department is considering alternative land uses. In this article, the perceptions of hunters and fishermen allowed on site for a limited time were examined, about environmental concerns, future land use, and cleanup options. Although loss of jobs was the foremost concern, preserving parts of the site had more support as a future land use than continuing the nuclear mission, and nearly three-quarters of the sample supported cleanup, regardless of cost. On-site employment was a significant indicator of lower concern about safety and environmental issues, less support for designating the site for research, and more concern for maintaining jobs.

Adolescent↗

PubMed1999

Revisiting the commons: local lessons, global challenges.

In a seminal paper, Garrett Hardin argued in 1968 that users of a commons are caught in an inevitable process that leads to the destruction of the resources on which they depend. This article discusses new insights about such problems and the conditions most likely to favor sustainable uses of common-pool resources. Some of the most difficult challenges concern the management of large-scale resources that depend on international cooperation, such as fresh water in international basins or large marine ecosystems. Institutional diversity may be as important as biological diversity for our long-term survival.

Conservation of Natural Resources↗

PubMed1999

Urban anglers' perception of risk from contaminated fish.

The Newark Bay Complex includes the Newark Bay, tidal portions of the Hackensack River, Passaic River, Arthur Kill, and Kill van Kull. It is a highly industrialized urban area including five counties and more than 20 local governments with a large racially-mixed population of more than 3 million people. In 1982, research conducted by the New Jersey Department of Environmental Protection (NJDEP) showed elevated levels of chemical contaminants in five species of fish and one type of crab in the Newark Bay Complex. Subsequently, the State of New Jersey adopted advisories to guide citizens on safe consumption practices for fish and crabs. Since then, fish consumption advisories have been issued primarily through the Fish and Game Digest, a publication distributed by the state to licensed anglers. However, anglers in the Complex are not required to have a fishing license because the waters are marine. Therefore, most anglers in this area do not receive advisory information. To gain greater insight into the information sources and risk perceptions of urban anglers, a survey was conducted of 300 anglers at 26 fishing and crabbing locations in the Newark Bay Complex during the summer and early fall of 1995. The objectives of the study were to learn anglers': (1) knowledge of fish consumption advisories; (2) belief in the advisories; (3) perception of how safe fish are to eat; (4) sources for information about fish and fishing; and (5) sources for information on fish consumption advisories. The study concluded that while 60% had heard about advisories, they either did not believe or were unconcerned about health effects from eating contaminated species. In addition, the most used source for information about fish and fishing was other fishermen, while newspapers were selected as a source for information about community news, health, and food safety.

Animals↗

PubMed1999

Recreation, consumption of wild game, risk, and the Department of Energy sites: perceptions of people attending the Lewiston, ID, "Roundup".

Several federal agencies are reclaiming land through remediation and restoration, and are considering potential future land uses that are compatible with current land uses and local needs. Understanding potential recreational and wild game consumption patterns and risk perceptions are critical for determining cleanup levels and assessing potential risk associated with certain uses. In this article, recreational rates of people attending the Lewiston "Roundup" rodeo in northwestern Idaho were examined, as well as their perceptions of the safety of consuming fish and game from two Department of Energy (DOE) facilities: the Hanford Site and the Idaho National Engineering and Environmental Laboratory (INEEL). These are two of DOE's largest sites. Lewiston is closer to Hanford, but is in the same state as INEEL. Men engaged in significantly higher hunting and fishing rates than women, but there were no gender differences in camping and hiking rates. Rates of hunting and camping decreased significantly with age, while rates of hiking were lowest for 31- to 45-yr-olds. Level of education generally was not related to rates of recreation. Over 70% of the subjects ate deer, elk, and self-caught fish; 30-50% ate grouse, moose, and waterfowl; and fewer people ate other game species. Overall, subjects were less concerned about eating the fish and game from INEEL than from Hanford, and more people thought Hanford should be cleaned up completely compared to INEEL. Mean rates of fishing, hiking, and camping all exceeded the DOE's maximum recreational exposure assumption of 14 d/yr used in their future use documents. Although at present people are generally not allowed access to DOE lands for recreation, recreation is one future land use being considered for these federal facilities. Given that some people would engage in multiple activities, the potential exists for people living in the general region of Hanford and INEEL to exceed the 14-d exposure assumption. The relative gender differences in recreational rates mean that men are potentially more at risk, particularly since hunting (on both sites) and fishing (on Hanford) are attractive.

Adolescent↗

PubMed1999

DNA preservation: a microsatellite-DNA study on ancient skeletal remains.

To determine the effect of environmental factors on the preservation of DNA, archeological teeth of approximately similar age but greatly differing site milieu were examined for DNA content. The complex relational system of locational milieu of the samples was reduced to its essential and, at the same time, easily measurable factors. These are temperature, humidity, pH value, the geochemical properties of the soil, the amount of postmortal organic substances and the general degree of microbial infestation in the respective soil. The relative DNA content in the samples was established by determining the rate of successful polymerase chain reaction (PCR) amplifications. Differences in quantity and quality of the results are attributed to the respective prevailing environmental factor or to the respective storage conditions. Dryness, low temperature and absence of microorganisms favors the preservation of DNA. The bioapatite of bones and teeth, like the DNA, are preserved under neutral or slightly alkaline conditions. Brief storage at room temperature does not affect the amount of amplifiable DNA but does affect the reproducibility of the results. Long storage outside a lab freezer reduces the amount and the reproducibility of DNA amplifications in ancient specimens.

Bone and Bones↗

PubMed1999

Individual sibling recognition in experimental broods of common tern chicks.

Studies of kin recognition in birds have usually examined parent-offspring recognition, while studies of sibling recognition are relatively rare. Using choice experiments, we studied the development of sibling recognition among common tern, Sterna hirundo, chicks and tested the cues used for recognition. We collected newly hatched common tern chicks and raised them in a laboratory in 10 artificial broods of three. Chicks showed a significant preference for broodmates ('siblings') over familiar nonsiblings (nonsiblings from neighbouring broods) when first tested at 4 days posthatching, earlier than previously reported. Preferential approach to siblings was most common in broods with low levels of intrabrood aggression. Responsiveness of test chicks was highest when test chicks and stimulus chicks could both see and hear each other and lowest when they could only hear each other. Sibling-biased approach did not depend on stimulus and test chicks seeing each other, only on test chicks seeing (and probably hearing) stimulus chicks. Surprisingly, no preference was shown for siblings over strange nonsiblings, suggesting that a preference for siblings may involve learning the identity of not only siblings, but also of chicks from neighbouring broods. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗

PubMed1999

American Indians, hunting and fishing rates, risk, and the Idaho National Engineering and Environmental Laboratory.

Hunting, fishing, and recreational rates of 276 American Indians attending a festival at Fort Hall, near the Idaho National Engineering and Environmental Laboratory (INEEL), were examined. Nearly half of the sample lived on the Fort Hall Reservation, and half were American Indians from elsewhere in the western United States. An additional 44 White people attending the festival were also interviewed. The hypothesis that there are differences in hunting, fishing, and recreational rates as a function of tribal affiliation, educational level, gender, and age was examined. Information on hunting and fishing rates are central for understanding potential exposure scenarios for American Indians if the Department of Energy's INEEL lands are ever opened to pubic access, and the data are important because of the existence of tribal treaties that govern the legal and cultural rights of the Shoshone-Bannock regarding INEEL lands. Variations in hunting, fishing, and photography rates were explained by tribal affiliation (except fishing), gender, age, and schooling. Hunting rates were significantly higher for Indians (both those living on Fort Hall and others) than Whites. Men engaged in significantly higher rates of outdoor activities than women (except for photography). Potential and current hunting and fishing on and adjacent to INEEL was more similar among the local Whites and Fort Hall Indians than between these two groups and other American Indians.

Adult↗

PubMed1999

Lack of demonstratable effects of pollutants on cyt b sequences in wood ducks from a contaminated nuclear reactor cooling pond.

The effects of low levels of radiation on DNA mutation rates are largely unknown for free-living vertebrates. In this study we investigated the effects of contamination from cooling ponds at a nuclear production facility in South Carolina on the mutation rates in mitochondrial DNA in wood ducks (Aix sponsa). Specifically, we sequenced a 433-bp portion of the cytochrome b gene from 18 female-offspring pairs of wood ducks from contaminated ponds and 2 female-offspring pairs from control ponds. Very low haplotype diversity was observed overall, and no case of mutation between female and offspring could be satisfactorily documented. This suggests that the levels of radioactive contamination in these cooling ponds have little effect on the mutation rate of mitochondrial DNA in these waterfowl and that mitochondrial DNA may not be as sensitive an indicator as previously anticipated.

Animals↗

PubMed1999

Metal concentrations in the eggs of endangered Florida scrub-jays from central Florida.

We analyzed metal levels in the eggs of the endangered Florida scrub-jay (Aphelocoma coerulescens), an extremely sedentary and modestly long-lived passerine bird. Eggs were obtained as part of the long-term study of this species at the Archbold Biological Station, located in south central Florida. Following a brief and usually short dispersal, Florida scrub-jays remain in a permanent territory in their scrub oak habitat, where they feed mainly on insects and acorns. As they are low on the food chain and sedentary, we expected levels of contaminants to be comparatively low and to reflect the local environment. No significant yearly differences existed for any metal between eggs collected in 1997 (n = 11) and 1998 (n = 5). Arithmetic mean metal concentrations (whole egg, dry weight) were low for arsenic (34 ppb), cadmium (25 ppb), mercury (74 ppb), and lead (66 ppb), intermediate for chromium (226 ppb), and higher for selenium (1,470 ppb) and manganese (2,230 ppb). Except for the low mercury value, all these means were within the range of mean values reported for a wide range of nonpasserine species, including those at high trophic levels, but are lower than concentrations associated with abnormalities in birds. The three essential elements (chromium, selenium, and manganese) were approximately normally distributed, whereas arsenic, cadmium, lead, and mercury were highly skewed (arithmetic mean much higher than geometric mean).

Animals↗

PubMed1999

Future Land Use and Concerns About the Idaho National Engineering and Environmental Laboratory: A Survey of Urban Dwellers.

/ We examined environmental concerns and future land-use preferences of 487 people attending the Boise River Festival in Boise, Idaho, USA, about the Idaho National Engineering and Environmental Laboratory (INEEL), owned by the US Department of Energy (DOE). We were particularly interested in the perceptions of urban dwellers living at some distance from the facility, since attitudes and perceptions are usually examined for people living near such facilities. More than 50% of the people were most worried about contamination and about waste storage and transport, another 23% were concerned about human health and accidents and spills, and the rest listed other concerns such as jobs and the economy or education. When given a list of possible concerns, accidents and spills, storage of current nuclear materials, and storage of additional nuclear materials were rated the highest. Thus both open-ended and structured questions identified nuclear storage and accidents and spills as the most important concerns, even for people living far from a DOE site. The highest rated future land uses were: National Environmental Research Park, recreation (including hiking, camping, fishing and hunting), and returning the land to the Shoshone-Bannock tribes; the lowest rated future land uses were homes and increased nuclear waste storage. These relative rankings are similar to those obtained for other Idahoans living closer to the site and for people living near the Savannah River Site, another DOE facility in South Carolina. The concern expressed about accidents and spills and waste storage translated into a desire not to see additional waste brought to INEEL and a low rating for using INEEL for building homes.KEY WORDS: Future land use; Perceptions; Recreation; Hazardous waste; Department of Energy; Idaho National Engineering and Environmental Laboratory.http://link.springer-ny.com/link/service/journals/00267/bibs/24n4p532.html</HEA

Journal Article↗

PubMed1999

Fishing in urban New Jersey: ethnicity affects information sources, perception, and compliance.

Recreational and subsistence angling are important aspects of urban culture for much of North America where people are concentrated near the coasts or major rivers. Yet there are fish and shellfish advisories for many estuaries, rivers, and lakes, and these are not always heeded. This paper examines fishing behavior, sources of information, perceptions, and compliance with fishing advisories as a function of ethnicity for people fishing in the Newark Bay Complex of the New York-New Jersey Harbor. We test the null hypothesis that there were no ethnic differences in sources of information, perceptions of the safety of fish consumption, and compliance with advisories. There were ethnic differences in consumption rates, sources of information about fishing, knowledge about the safety of the fish, awareness of fishing advisories or of the correct advisories, and knowledge about risks for increased cancer and to unborn and young children. In general, the knowledge base was much lower for Hispanics, was intermediate for blacks, and was greatest for whites. When presented with a statement about the potential risks from eating fish, there were no differences in their willingness to stop eating fish or to encourage pregnant women to stop. These results indicate a willingness to comply with advisories regardless of ethnicity, but a vast difference in the base knowledge necessary to make informed risk decisions about the safety of fish and shellfish. Although the overall median income level of the population was in the $25,000-34,999 income category, for Hispanics it was on the border between $15,000-24,999 and $25,000-34,999.

Black or African American↗

PubMed1999

Factors in exposure assessment: ethnic and socioeconomic differences in fishing and consumption of fish caught along the Savannah River.

South Carolina has issued fish consumption advisories for the Savannah River based on mercury and radionuclide levels. We examine differences in fishing rates and fish consumption of 258 people interviewed while fishing along the Savannah River, as a function of age, education, ethnicity, employment history, and income, and test the assumption that the average consumption of fish is less than the recreational value of 19 kg/year assumed by risk assessors. Ethnicity and education contributed significantly to explaining variations in number of fish meals per month, serving size, and total quantity of fish consumed per year. Blacks fished more often, ate more fish meals of slightly larger serving sizes, and consumed more fish per year than did Whites. Although education and income were correlated, education contributed most significantly to behavior; people who did not graduate from high school ate fish more often, ate more fish per year, and ate more whole fish than people who graduated from high school. Computing consumption of fish for each person individually indicates that (1) people who eat fish more often also eat larger portions, (2) a substantial number of people consume more than the amount of fish used to compute risk to recreational fishermen, (3) some people consume more than the subsistence level default assumption (50 kg/year) and (4) Blacks consume more fish per year than Whites, putting them at greater risk from contaminants in fish. Overall, ethnicity, age, and education contributed to variations in fishing behavior and consumption.

Adolescent↗

PubMed1999

Pharmacokinetics of ketorolac after intravenous and oral single dose administration in dogs.

The pharmacokinetics of ketorolac (Toradol), a human non-narcotic, nonsteroidal anti-inflammatory drug (NSAID) of the pyrrolo-pyrrole group, was studied in six mixed breed dogs of varying ages (1-5 years). The study was performed using a randomized crossover design, with each dog initially assigned to one of two groups (intravenous (i.v.) or oral (p.o.)). Each group of three dogs received either the injectable or oral formulation of ketorolac tromethamine at 0.5 mg/kg. Serial blood samples were collected before and over 96 h following treatment. Samples were analysed by reverse phase HPLC. Individual ketorolac plasma concentration-time curves were initially evaluated by computerized curve stripping techniques followed by nonlinear least squares regression. Following i.v. administration mean (+/- SD) pharmacokinetic parameters were: elimination half-life (t1/2 beta) = 4.55 h, plasma clearance (Clp) = 1.25 (1.13) mL/kg/min, and volume of distribution at steady state (Vss) = 0.33 (0.10) L/kg. Mean (+/- SD) p.o. pharmacokinetic values were: t1/2 beta = 4.07 h, time to reach maximum concentration (tmax) = 51.2 (40.6) min, and p.o. bioavailability (F) = 100.9 (46.7)%. These results suggest that the pharmacodisposition characteristics of a clinically effective 0.5 mg/kg i.v. or p.o. single dose of ketorolac tromethamine administered to dogs is fairly similar to that observed in humans.

Administration, Oral↗