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PubMed1994

A commentary on the NRC report "Science and judgment in risk assessment".

This article provides a brief overview of the report "Science and Judgment in Risk Assessment," prepared by a Committee of the National Research Council/National Academy of Science in response to a U.S. Environmental Protection Agency request mandated by the Clean Air Act Amendments of 1990 (CAAA-1990). The report critiques EPA's current approaches for characterizing human cancer risks from exposure to chemicals and offers recommendations for the conduct of future cancer risk assessments, especially those required in implementing the CAAA-1990 provisions which are concerned with hazardous air pollutants. The report offers specific recommendations that address the role of default options, data needs, methods and models, uncertainty, variability, and the aggregation of data. A cross-cutting theme of the report is the use of an iterative approach in which screening assessments with limited data and, of necessity, default options used in the absence of specific scientific data may be performed initially followed by subsequent assessments, as needed, in which increasing amounts of data are developed and incorporated. In some instances, the specific data on a given chemical or pollutant source will replace conservative default options used in earlier assignments. The report includes two authored appendices that address issues related to the use of default options and their replacement by specific scientific information. One appendix by Finkel advocates a principle of "plausible conservatism" for choosing and altering default options and in making cancer risk estimates. A second appendix by McClellan and North advocates the full use of scientific information in the risk assessment process. This article gives major attention to the key aspects of the NRC/NAS report, especially those dealing with the use and replacement of default options. The default options and the extent to which the options are replaced with specific science have major impact on the final quantitation of cancer risk for exposure to chemicals.

Air Pollution↗

PubMed2001

Ephedra and its application to sport performance: another concern for the athletic trainer?

OBJECTIVE: The ma huang herb, otherwise known as ephedra, has gained widespread popularity as an ergogenic supplement. With the sympathomimetic alkaloid ephedrine as its primary active ingredient, ma huang is marketed to reduce fatigue; increase strength, power, and speed; decrease reaction time; and improve body composition. Although numerous side effects have been associated with the use of ma huang, its popularity in athletes continues to grow. This review provides rationale for the ergogenic claims regarding ma huang and compares and contrasts those claims with data from scientifically controlled investigations. DATA SOURCES: MEDLINE and SPORT Discus were searched from 1970 to 2000 using the key words ma huang, ephedra, and ephedrine in combination with humans, exercise, performance, and side effects. DATA SYNTHESIS: Ephedrine has been used alone or in combination with other drugs as an effective weight-loss agent. The weight loss has been attributed to thermogenic and lipolytic effects which, in combination with the central nervous system stimulating effects, have also resulted in its use as an ergogenic aid. Most of the scientific data, however, do not support manufacturers' ergogenic claims, and numerous side effects have been associated with ephedrine use. Thus, the safety and efficacy of ma huang as an ergogenic supplement must be questioned. CONCLUSIONS/RECOMMENDATIONS: It appears that the risks associated with the use of ma huang far outweigh any possible ergogenic benefits. Thus, it is extremely important that athletic trainers educate athletes on these issues so they can continue to perform at an optimum level in a safe and healthy manner.

Journal Article↗

PubMed2001

Choose a diet that is low in saturated fat and cholesterol and moderate in total fat: subtle changes to a familiar message.

"Choose a diet that is low in saturated fat and cholesterol and moderate in total fat," issued in Nutrition and Your Health: Dietary Guidelines for Americans in the year 2000, has an interesting and lengthy history. The first guideline, for which there was extensive scientific data to show that dietary excess increased chronic disease risk, prompted much scientific discussion and debate when implemented as dietary guidance. Three major changes in the guideline are noted since it was issued in 1980, i.e., numerical goals for dietary fats; the applicability of recommended fat intakes for all individuals > or =2 y old; and rewording to emphasize reducing saturated fat and cholesterol intakes. The shift in emphasis includes the terminology moderate fat, which replaces the phrasing low fat. National data about the food supply, the population's dietary intake, knowledge, attitudes and behaviors, and nutritional status indicators (e.g., serum cholesterol levels) related to dietary fats help to monitor nutrition and health in the population. Experts consider that national data, although not without limitations, are sufficient to conclude that U.S. intakes of fats, as a proportion of energy, have decreased. The lower intakes of saturated fat and cholesterol are consistent with decreases in blood cholesterol levels and lower rates of coronary mortality over the past 30 years. Strategies are needed and some are suggested, to further encourage the population to achieve a dietary pattern that is low in saturated fat and cholesterol and moderate in total fat. Other suggestions are offered to improve national nutrition monitoring and surveillance related to the guideline.

Age Factors↗

PubMed1989

An analog data acquisition board for the Macintosh II.

The Macintosh II has the hardware to make a good scientific data acquisition and data processing machine. The data acquisition boards currently available do not sample multiple channels simultaneously. They are also relatively slow. We have designed a fast Analog-to-Digital Board for the Macintosh II that samples eight channels at once. This board acquires data with sampling periods from 1 microsecond to 1.6777215 seconds in increments of 100 nanoseconds. Any jitter is due to the stability of the clock which is about one part per billion. The actual analog-to-digital conversion time is 500 nanoseconds with another 500 nanoseconds taken up by the track-and-hold amplifier acquisition time and the multiplexer setting time. The board samples as many as eight channels, giving 12-bit resolution for signals between plus and minus 2.5 volts. For eight channels the maximum Nyquist frequency is 62.5 KHz. The board will acquire single-channel data that has frequencies up to 500 KHz. Simultaneous comparisons of two channels can be made for signals that have a highest frequency component of 250 KHz. Thirty-eight integrated circuits were used on a single-slot board that connects to the Macintosh II's 32-bit NuBus.

Analog-Digital Conversion↗

PubMed2006

Spectral imaging microscopy web sites and data.

The Internet is enabling greater access to spectral imaging publications, spectral graphs, and data than that was available a generation ago. The spectral imaging systems discussed in this issue of Cytometry work because reagent and hardware spectra are reproducible, reusable, and provide input to spectral unmixing and spectral components recognition algorithms. These spectra need to be readily available in order to determine what to purchase, how to use it, and what the output means. We refer to several commercially sponsored and academic spectral web sites and discuss our spectral graphing and data sites. Sites include fluorescent dye graph servers from Invitrogen/Molecular Probes, BD Biosciences, Zeiss/Bio-Rad Cell Sciences, and filter set servers from Chroma Technology and Omega Optical. Several of these sites include data download capabilities. Recently, two microscope manufacturers have published on their web sites transmission curves for select objective lenses-crucial data for anyone doing multiphoton excitation microscopy. Notable among the academic sites, PhotoChemCAD 2.0 has over 200 dyes and a downloadable database/graphing program, and the USC-A Chemistry UV-vis Database displays absorption spectra of many dyes and indicators used in clinical histology and pathology. Our Fluorescent Spectra graphing/calculator site presents dyes, filters, and illumination data from many of these and additional sources. PubSpectra is our free download site which uses Microsoft Excel files as standardized human/machine readable format with over 2,000 biomedical spectra. The principle that data is not subject to copyright provides a framework in which all scientific data should be made freely accessible.

Algorithms↗

PubMed2001

Stream phosphorus transport in the Lake Tahoe basin, 1989-1996.

Lake Tahoe is undergoing the initial stages of cultural eutrophication due to human alteration of the airshed and watershed. The lake's switch from nitrogen (N) to phosphorus (P) limitation has been attributed primarily to atmospheric N loading. This places an increased importance on controlling watershed movement of P to the lake. A stream water quality monitoring data set consisting of nine streams in the Lake Tahoe basin has been analyzed to characterize the spatiotemporal variation of P delivery to the lake. This data is from the Lake Tahoe Interagency Monitoring Program (LTIMP), which provides scientific data for planning and regulatory agencies to address environmental problems in the Lake Tahoe basin. Results indicate that P delivery (concentrations, loads) varies greatly at interannual, seasonal, and spatial scales. Annual and seasonal total P (TP) concentrations can vary up to three orders of magnitude in a given stream and are strongly associated with suspended sediment. Particulate P is the major form of P transported by Tahoe streams and was strongly correlated with percent surficial geologic deposits, which are primarily located near streams. Tahoe streams with the highest annual P concentrations often had the lowest annual P loads, and visa versa. P loading is greatest during the spring snowmelt (75% of annual average). Potential watershed parameters influencing P delivery to Lake Tahoe have been identified as precipitation, basin area, basin steepness, and road and human development coverage. Results also suggest that human development impacts on stream P loads are most prevalent during high precipitation years. Identification and quantification of stream sediment and P sources such as streambanks and impervious surface is necessary to aid in watershed restoration efforts.

Eutrophication↗

PubMed2002

Seizures and the basal ganglia: a review of the clinical data.

This article attempts an overview of the clinical and electrophysiological evidence supporting the involvement of the basal ganglia in epileptic seizures. In contrast to animal data, evidence for a role of these structures in human epilepsies is lacking. However, from the theoretical point of view, it remains conceivable that, given their strong interconnectivity, basal ganglia could be functionally linked to the cerebral cortex during an epileptic seizure. Several clinical ictal aspects have been suggested to be compatible with the involvement of basal ganglia, namely, ictal dystonic posturing during temporal lobe seizures, rotatory seizures and paroxysmal dyskinesia-like seizures. On the other hand, basal ganglia dysfunction may also influence some aspects of epilepsy, as suggested by pure basal ganglia pathology such as Parkinson's disease, or the described effect of an acute basal ganglia lesion in epileptic patients. The data discussed in this review may stimulate further research to link basic scientific data to human epilepsies, and lead to the development of novel therapeutical solutions.

Animals↗

PubMed1983

An additional basic science for clinical medicine: I. The constraining fundamental paradigms.

The four main conceptual paradigms of basic biomedical research are that the explication of mechanisms is a primary goal of science; that scientific data must be "hard"; that formulation of hypotheses and counter-hypotheses is a principal creative challenge; and that experiments are the main mechanism for using scientific methods to conduct investigations. Although suitable for the spectacular accomplishments of biomedical research, these paradigms do not offer a satisfactory foundation for the additional basic science needed in the managerial decisions of patient care. For these decisions, the primary scientific goal is usually prediction rather than explication alone; the crucial data often involve "soft" information about clinical and personal phenomena; and the main creative challenge is to develop an improved methodology for getting adequate data and making unbiased comparisons. Although the experiments conducted as randomized clinical trials have been scientifically helpful, the improved methods will have to include evidence obtained in the often unplanned "experiments" of ordinary clinical practice.

Clinical Trials as Topic↗

PubMed2005

Principles and practices of health risk assessment under current EU regulations.

Risk assessments serve as the foundation of regulatory decision-making on whether to take actions to reduce (or otherwise manage) a toxicological or ecotoxicological risk or not. To understand the complex process that leads from the generation of scientific data, via risk assessment to risk management decision-making, close studies of the scientific basis and risk assessment methods must be undertaken. This paper consists of two main parts. In the first part the principles of the European Union process for risk assessments, as defined by legislations and official guidelines, are briefly outlined. In the second part the actual workings of this system are exemplified by the results from case studies of the risk assessment processes for trichloroethylene and for acrylamide. The analysis and comparison of these two cases illustrates: (1) that generation of a large amount of data does not ensure consensus among risk assessors, (2) that controversy can regard different levels of detail, (3) that controversy can arise at different organizational and theoretical levels, (4) that risk assessments may be subject to (public) criticism even if the experts agree, and (5) that "scientific" controversies have a significant policy component.

Acrylamide↗

PubMed2004

Communicating original research in chemistry and related sciences.

The availability of scientific information in electronic form is the convergence of traditional journal publishing, electronic communications, and the widespread availability of computer technology. This revolution in scientific communication has its roots in developments that started in the mid-19th century and culminated with the extraordinary progress in telecommunications and computer technology in the latter years of the 20th century. Eighty-three percent of scientific journals are now available online. The benefits of electronic journals include rapid publication, instantaneous linking to external information sources, and the capability to deliver new types of information. To date neither electronic-only nor preprint servers have been well received by the chemical sciences community. Continued advances in telecommunications, computer technology, and acquisition of scientific data in structured formats hold promise for even greater advances in communication of scientific information.

Journal Article↗

PubMed1989

Asserting scientific authority. Cognitive development and adolescent legal rights.

The APA uses amicus briefs to communicate scientific knowledge to the legal system. There can be tension, however, between promoting the social good through law and the disinterested reporting of scientific data. This article examines this conflict by discussing two APA amicus briefs filed in the United States Supreme Court in cases involving adolescents' abortion rights. The Court has restricted adolescents' rights to make important life decisions in part because adolescents have been presumed to lack competence and maturity. The briefs argued that developmental theory and data confirm that adolescents and adults have equivalent decision-making capacities. The scientific arguments in the briefs, however, do not justify this assertion. Analysis of the briefs illuminates some dimensions describing the role of a scientific statement in a legal brief. These dimensions identify ways to limit scientific claims about the evidence at hand to avoid overstatement. The primary danger of overstatement is that it undermines psychology's claim to expert authority in assisting in the formation of law and the shaping of social institutions.

Abortion, Induced↗

PubMed2004

Anabolic steroid usage in athletics: facts, fiction, and public relations.

Anecdotal evidence suggests the widespread usage of anabolic steroids among athletes (20-90%), particularly at the professional and elite amateur levels. In contrast, scientific studies indicate that usage is rare and no higher than 6%. Conclusions from scientific studies suggest that anabolic steroid usage declines progressively from high school to college and beyond; however, anecdotal evidence claims the opposite trend. In this clash between "hard" scientific data vs. "soft" anecdotal information, it is natural that professionals would gravitate toward scientifically based conclusions. However, in the case of anabolic steroids (a stigmatized and illegal substance), should word-of-mouth testimony from individuals closest to the issues--those who have participated in and coached sports, those who have served as drug-testing overseers, and journalists who relentlessly track leads and verify sources--be set aside as irrelevant? Not if a complete picture is to emerge. In this review, hard scientific evidence is placed on the table side-by-side with soft anecdotal evidence, without weighting or bias. The purpose is to allow the opportunity for each to illuminate the other and, in so doing, potentially bring us a step closer to determining the true extent of anabolic steroid usage in athletics.

Anabolic Agents↗

PubMed1987

Testing of chemicals, safety evaluation and regulation at European Community level.

Regulations regarding safety of chemicals are covered by the following main programmes: health and safety at work, internal market and technical harmonization, environmental and consumer protection. The elaboration of draft Community legislation by the Commission for transmission to Council and the European Parliament requires an evaluation of the scientific data together with a determination of the technical possibilities and economic impact. Studies, scientific committees, national experts and tripartite advisory committees are used. For new chemicals premarketing testing is required for labelling. The testing scheme is described. From the legislative point of view chemical safety is considered essentially in terms of six broad categories: air and water pollution and handling of toxic wastes, classification and labelling of dangerous chemicals and preparations, limitations of use of dangerous substances and preparations, occupational health and safety measures, prevention of major industrial chemical accidents, public health measures related to dangerous chemicals. The classification and labelling of carcinogens and the regulation of the various facets of the use of lead will illustrate these regulatory procedures.

Accident Prevention↗

PubMed1995

Is quinine effective and safe in leg cramps?

Muscle cramp is a recurrent and painful condition and a common complaint among elderly subjects and patients treated with hemodialysis. It is commonly nocturnal and can disturb a good night's sleep. No specific cause can be identified; therefore, therapy is mostly symptomatic. Quinine sulfate, an antimalarial drug, is widely used as an effective therapy for idiopathic leg cramps. Several double-blind, randomized, placebo-controlled studies have questioned the effectiveness of quinine in leg cramps; whereas other studies have shown significantly more benefit with use of quinine in reducing the frequency and severity of cramps compared with placebo or vitamin E. The mechanism of this beneficial effect is obscure, however. Quinine appears to decrease the excitability of the motor end plate, thereby reducing the muscle contractility. Most patients consider quinine beneficial for their leg cramps, which is difficult to refute by scientific data. More important, cramp is a subjective symptom, therefore difficult to measure objectively. Consequently, scientific studies designed to prove or disprove the effectiveness of quinine can be subject to flaws. Further, a dosage of 200 to 300 mg of quinine every night has not been shown to cause significant side effects. Nevertheless, quinine should be used in a small dose and cautiously, especially in the elderly and patients with renal failure, and should be avoided in patients with liver disease.

Aged↗

PubMedDate not supplied

Improving the nurse-patient relationship: a multi-faceted approach.

AIM: The aim of the symposium was to provide strategies to help overcome different types of nurse-patient communication problems, with particular reference to the renal disease setting. In this context, the importance of effective patient education to increase patient compliance played a vital role. The case studies presented and the subsequent discussions helped increase the awareness of important medical aspects, such as the increased risk of anaemia-related complications in diabetic patients and the importance of early referral and anaemia treatment in patients with renal disease. Strategies proposed were supported by best practice guidelines and the latest scientific data. METHODOLOGY: A moderator led an interactive session that included two video case studies, scientific presentations and panel discussions. The audience played an active role by expressing their opinions via keypads. The case studies and the views of the audience were discussed by a panel of experts, who related their experiences and advice. CONCLUSIONS: A good nurse-patient relationship is essential to meet the clinical, psychological and social needs of the patient in order to optimise treatment. Effective patient education is an important tool to meet patient's needs and increase treatment compliance. Moreover, optimal treatment of patients requires a multidisciplinary approach to allow early identification and treatment of associated co-morbidities. Anaemia-related co-morbidities are particularly important in diabetic patients with renal disease, since this patient group develops anaemia at an early stage and has a significantly increased risk of cardiovascular complications. In renal disease, there are well-defined guidelines and treatment options for anaemia-related co-morbidities, which can easily be adapted to a patient's needs in order to offer flexible, individualised treatment with the aim of improving treatment outcomes.

Adaptation, Psychological↗

PubMed1999

Treatment of Helicobacter pylori: where are we now? What are the key questions?

Over the 14 years since Helicobacter pylori came to the attention of the medical community, we have reached the position that the organism is generally believed to be a serious pathogen. It causes a chronic infection with complications that include gastric and duodenal ulcer, gastric mucosa-associated lymphoid tissue lymphoma and gastric cancer. It is therefore an important cause of morbidity and mortality. We still do not have a perfect treatment for the infection, but enormous strides have been made since its discovery and acceptable treatments are now available. The best of these are the acid pump inhibitor- and ranitidine bismuth citrate-based triple therapies that provide 85-95% eradication in most studies. Better treatments and vaccination programmes may become available now that the Helicobacter genome has been decoded, raising the possibility of 'designer' antibiotics and vaccines. In the meantime, the current key questions are: How can our current therapies be improved? Who should be treated? What, if any, are the potential risks of widespread H. pylori eradication? And how is the organism transmitted? Without doubt, many of these questions will be addressed in the succeeding years. The papers presented in these proceedings represent an up-to-date analysis (much of it based on new data) by recognized experts. The views expressed are often provocative, but are backed by scientific data.

Anti-Ulcer Agents↗

PubMed2001

["What's up, doc?" The context, limitations, and issues for clinicians in evidence-based medicine].

BACKGROUND: The evidence-based medicine approach could be considered a new name given to the contemporary medicine dialectics between the practice of an art and the insight provided by the best scientific data. METHODS: In this 3-part article, the background is introduced, then the design limits of the approach are shown through an example of metaanalysis applied to 4 psychiatric situations, and the conclusion is left to a clinician. RESULTS: In the background, evidence-based medicine is first associated with the period of budget cuts, then with the widespread popularity of the Internet. A few snags in this seemingly flawless system are seen when the subjective items involved in metaanalysis are taken into account. There are also problems linked to unpublished data, homogenization of populations studied, and the assumption that only random studies lead to valid scientific knowledge. The clinician will probably not be surprised and will link this to the old debate between empiricists and rationalists. CONCLUSION: In its purest form, evidence-based medicine supports the necessary continuous inquiry about our practices.

Antipsychotic Agents↗

PubMed1999

[Consensus conferences and guidelines in gastroenterology: an illusion].

Evidence-based medicine describes the present-day situation of a rational medicine which has its origins in the 19th century. At present evidence-based medicine is an ideal which is unattainable due to inadequate data from randomised controlled studies. Guidelines and consensus conferences which are not based on clearcut scientific data from controlled prospective and randomised studies fail to meet the requirements of evidence-based medicine and so cannot improve patient management. Guidelines and consensus conferences do not substantially reduce health costs.

Consensus Statements as Topic↗