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Biomedical subjects

B B Johnson

Publications and source records attributed to B B Johnson.

17 recordsLinked to original sources
PubMed2003

Perceptions of recreational fishing boat captains: knowledge and effects of fish consumption advisories.

The impacts of fish consumption advisories on recreational and subsistence fishing, particularly in fresh waters, have been examined extensively. By contrast, little attention has focused on organized recreational fishing, such as from party and charter boats, and particularly for salt water fish. We interviewed 93 New Jersey boat captains to determine their knowledge about fish consumption advisories, and whether, in their opinion, clients knew of fish consumption advisories, and whether they thought advisories had an effect on recreational fishing and their businesses. Advisories were ranked by captains as a moderate influence on the success of their business, less so than number of fish caught, strength of the economy, overfishing by commercial boats, and management regulations. Only one boat captain had not heard warnings about eating fish, but what captains said they had heard was mixed in its accuracy and completeness. Clients expect captains to know about fish, and about half of boat captains said clients had asked about the safety of eating fish. Captains who felt advisories were affecting their businesses tended to fish for species without high levels of mercury (except for bluefish) or PCBs, the primary contaminants of concern for state advisories and federal advice. However, these captains worked closer to areas (e.g., Raritan Bay complex and New York Harbor) subject to advisories than did other captains, and were more prone to say that management regulations (e.g., fish size, creel limits, seasons) and marketing and advertising by the industry or state were strong influences on the success of their seasons. Comparing captains who thought advisories had some or great effect (60%) versus those reporting "no effect" (40%), there was no difference in the mean percentage of trips targeting high mercury species such as swordfish and shark. Many captains said they would or might post advisories, but 42% of the boat captains said they would not post consumption warnings if the state provided them. The significant portion (at least 15%) of saltwater fishing supported by these businesses suggests that these captains are an important conduit for future risk communication.

Animals↗
PubMed2002

Phytotoxicity and mammalian cytotoxicity of macrocyclic trichothecene mycotoxins from Myrothecium verrucaria.

Macrocyclic trichothecene toxins produced by Myrothecium verrucaria (a phytopathogen of interest in biological weed control) and the non-trichothecene toxin atranone B from Stachybotiys atra were tested for phytotoxicity in duckweed (Lemna pausicostata L.) plantlet cultures and kudzu (Pueraria lobata L.) leaf disc assays, and for mammalian cytotoxicity in four cultured cell lines. Roridin E and H, epi-isororidin E, and verrucarin A and J were phytotoxic (half-maximal effect in the concentration range 0.1-9.7 microM on duckweed and 1.5->80 microM on kudzu) and cytotoxic to mammalian cell lines (half-maximal inhibition of proliferation in the concentration range 1-35 nM). Trichoverrins A and B and atranone B were moderately phytotoxic (half-maximal effect in the concentration range 1 9-69 microM on duckweed and 13->80 microM on kudzu) and weakly cytotoxic with mammalian cell lines (half-maximal inhibition of proliferation in the concentration range 0.3->2 microM).

3T3 Cells↗
PubMed1999

Ethical issues in risk communication: continuing the discussion.

Proposed in this article is one possible framework for classifying multiple types of ethical issues in risk communication research and practice to help continue a discussion initiated in 1990 by Morgan and Lave. Some of the questions that each stage of the process for planning risk communication strategies appears to pose for ethics are discussed (e.g., selecting issues to be communicated, knowing the issue, dealing with constraints). Also discussed briefly are some issues raised by the possibility that risk communicators aspire to the status of a profession. The purpose is to foster discussion rather than issue a conclusive statement on the topic, because its very nature makes a definitive pronouncement indefensible.

Communication↗
PubMed1995

Presenting uncertainty in health risk assessment: initial studies of its effects on risk perception and trust.

Some analysts suggest that discussing uncertainties in health risk assessments might reduce citizens' perceptions of risk and increase their respect for the risk-assessing agency. We tested this assumption with simulated news stories varying simple displays of uncertainty (e.g., a range of risk estimates, with and without graphics). Subjects from Eugene, Oregon, read one story each, and then answered a questionnaire. Three studies tested between 180 and 272 subjects each. Two focus groups obtained more detailed responses to these stories. The results suggested that (1) people are unfamiliar with uncertainty in risk assessments and in science; (2) people may recognize uncertainty when it is presented simply; (3) graphics may help people recognize uncertainty; (4) reactions to the environmental problems in the stories seemed affected less by presentation of uncertainty than by general risk attitudes and perceptions; (5) agency discussion of uncertainty in risk estimates may signal agency honesty and agency incompetence for some people; and (6) people seem to see lower risk estimates (10(-6), as opposed to 10(-3)) as less credible. These findings, if confirmed, would have important implications for risk communication.

Adult↗
PubMed1992

Residential exposure to chromium waste--urine biological monitoring in conjunction with environmental exposure monitoring.

To determine whether a population living on or adjacent to four sites of chromate production waste was measurably exposed to environmental chromium, spot samples of urine were collected along with wipe samples of household dust and lifestyle/activity interview data. Findings were compared to those from a control population in two communities with no significant chromium use or waste sites. Urine samples were collected and analyzed, employing measures to minimize background chromium contamination. The average Cr mass in dust was 3.7 times that in control houses. The mean creatinine-corrected urine Cr (Cr/c) level of the exposed subgroup residing in households in the 75th percentile of Cr mass in wipe samples was significantly greater than that of the control population. This subgroup was primarily located at a single exposure location. Using lifestyle/activity data, significantly elevated Cr/c urine levels were identified in other exposed subgroups defined by employment location and by outside play time. These data show an association between elevated exposure to chromium in household dust and elevated urine levels of chromium, consistent with residential exposure to chromate production waste. These data also suggest an association between chromium exposure and activities outside the home which are consistent with exposure to chromate production waste.

Adolescent↗
PubMed1991

Activated macrophage conditioned medium: identification of the soluble factors inducing cytotoxicity and the L-arginine dependent effector mechanism.

Conditioned medium (CM) from cultures of cytotoxic activated macrophages causes inhibition of mitochondrial respiration, DNA synthesis, and aconitase activity in murine EMT-6 mammary adenocarcinoma cells by an L-arginine dependent effector mechanism. CM induces cytotoxicity and nitrite synthesis in EMT-6 cells in a dose dependent manner. We have identified the soluble factors in CM that induce cytotoxicity and synthesis of inorganic nitrogen oxides from L-arginine by EMT-6 cells. Using functional inhibition experiments, the activity of lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF alpha), and interferon gamma (IFN gamma) in CM was investigated. The LPS inhibitor polymyxin B and TNF alpha antibody produced a modest decrease in nitrite production, while IFN gamma antibody markedly inhibited both nitrite production and cytostasis. Simultaneous treatment with polymyxin B, TNF alpha antibody, and IFN gamma antibody reduced EMT-6 cell nitrite production by 81%, and cytostasis by 74%. By Western blot, IFN gamma and TNF alpha were shown to be present in CM. When CM was subjected to hydrophobic interaction chromatography, a single peak of activity was eluted, and Western blot showed that the active fractions contained IFN gamma. Furthermore, IFN gamma antibody neutralized the activity in these chromatographic fractions. We conclude that induction of inorganic nitrogen oxide synthesis from L-arginine by the synergistic combination of IFN gamma, TNF alpha, and LPS accounts for most of the biologic activity of CM, and that IFN gamma is the major priming factor.

Aconitate Hydratase↗
PubMed1981

Correlations between deoxyribonucleic acid structural parameters and calculated circular dichroism spectra.

Circular dichroism spectra are calculated for 68 different conformations of the bases in the double-stranded sequence of T-G-G-C-G-T-A-T-T-C-T and its complementary strand. All conformations are right-handed helices and include both published models and energy-minimized forms. Examination of the dependence of the circular dichroism band at 274 nm shows that the magnitude of the band is a linear function of both the helix winding angle and the base pair twist. Correlations of the magnitude of the circular dichroism with the distance between base pairs, the distance of the base pairs from the helix axis, or the tilt of the base pair relative to the helix axis are poorer.

Base Sequence↗
PubMed1977

The effect of serum oncotic pressure on serum cholesterol levels: a study in "normal" and nephrotic subjects.

Clinical data in neprtotic and nonnephrotic subjects were examined to help delineate the mechanism of hypercholesterolemia in nephrotic syndrome. Analyses of the relationship between total serum cholesterol and serum albumin levels and between total serum cholesterol and calculated serum oncotic pressure in 500 nonnephrotic individuals revealed strong positive correlations (r = 0.9714, p less than 0.001 and r = 0.9720, p less than 0.001, respectively). Serum beta-lipoprotein concentration was found to bear an inverse relationship to measured serum oncotic pressure in 13 nephrotic patients (r = -0.8192, p less than 0.01). Our results lend support to the thesis that serum oncotic pressure is the major governing factor in hypercholesterolemia in nephrotic syndrome.

Adolescent↗
PubMed1970

A method for the calculation of the relative contributions of recruitment and enhancement to human eccrine sweating.

The rate of eccrine sweating has been studied by collecting samples in unventilated capsules from human subjects following subdermal or intradermal injections of acetyl-beta-methylcholine and under moderate total body heat exposure. The rate of sweating in a given area of skin could increase by recruitment of fresh glands, enhanced output of the already active glands, or some combination of both.A theoretical analysis shows how recruitment and enhancement can be calculated separately, assuming the existence of a maximal rate of sodium reabsorption by eccrine sweat glands, a sodium concentration of 145 muEq/ml in the precursor fluid, the absence of significant water reabsorption, and the absence of back-diffusion of sodium. The results indicate that, depending on the experimental conditions, an increased rate of sweating can be attributed mainly to recruitment, to enhancement, or to a combination of both.

Absorption↗
PubMedDate not supplied

Biological markers in chromium exposure assessment: confounding variables.

An estimated two million tons of chromate production waste pollution has caused a major environmental and public health concern in Hudson County, New Jersey. As part of an occupational exposure assessment, urinary and red blood cell (RBC) chromium measurements were performed on 52 state employees who worked either near a contaminated site or elsewhere. Samples were collected so as to minimize contamination, and they were analyzed using sensitive techniques. These workers also completed a questionnaire that addressed potentially important third variables. Individual analyses suggested that exercise, drinking beer, past employment in chromium-related occupations, and diabetic status had an important effect on urinary chromium levels. These variables were entered into a regression model and were all found to be significant predictors of urinary chromium level (p less than .10). Some variables were also examined for their influence on RBC chromium level, but none had a measurable effect.

Adult↗
PubMedDate not supplied

Sexual abuse prevention: a rural interdisciplinary effort.

The alliance of social work and theater is a natural and powerful coalition. The cooperation of two undergraduate programs to produce a preventive program on sexual abuse education reached over 4,000 children. Social work was the catalyst in terms of identifying the need, obtaining grant money, and developing community support. Theater provided the talent to produce an outstanding performance. Communities planning to develop successful prevention programs must develop community support, clear goals, a well-trained follow-up team, education for professionals who work with children daily, a clear channel for reporting abuse, and an evaluation process. The use of volunteers keeps the cost of the project to a minimum.

Child↗