A systematic review of cardiovascular responses associated with ambient black carbon and fine particulate matter.

BACKGROUND: Exposure to fine particulate matter (PM2.5), an ambient air pollutant with mass-based standards promulgated under the Clean Air Act, and black carbon (BC), a common component of PM2.5, are both associated with cardiovascular health effects. OBJECTIVES: To elucidate whether BC is associated with distinct, or stronger, cardiovascular responses compared to PM2.5, we conducted a systematic review. We evaluated the associations of short- and long-term BC, or the related component elemental carbon (EC), with cardiovascular endpoints including heart rate variability, heart rhythm, blood pressure and vascular function, ST segment depression, repolarization abnormalities, atherosclerosis and heart function, in the context of what is already known about PM2.5. DATA SOURCES: We conducted a stepwise systematic literature search of the PubMed, Web of Science and TOXLINE databases and applied Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines for reporting our results. STUDY ELIGIBILITY CRITERIA: Studies reporting effect estimates for the association of quantitative measurements of ambient BC (or EC) and PM2.5, with relevant cardiovascular endpoints (i.e. meeting inclusion criteria) were included in the review. Included studies were evaluated for risk of bias in study design and results. STUDY APPRAISAL AND SYNTHESIS METHODS: Risk of bias evaluations assessed aspects of internal validity of study findings based on study design, conduct, and reporting to identify potential issues related to confounding or other biases. Study results are presented to facilitate comparison of the consistency of associations with PM2.5 and BC within and across studies. RESULTS: Our results demonstrate similar associations for BC (or EC) and PM2.5 with the cardiovascular endpoints examined. Across studies, associations for BC and PM2.5 varied in their magnitude and precision, and confidence intervals were generally overlapping within studies. Where differences in the magnitude of the association between BC or EC and PM2.5 within a study could be discerned, no consistent pattern across the studies examined was apparent. LIMITATIONS: We were unable to assess the independence of the effect of BC, relative the effect of PM2.5, on the cardiovascular system, nor was information available to understand the impact of differential exposure misclassification. CONCLUSIONS: Overall, the evidence indicates that both BC (or EC) and PM2.5 are associated with cardiovascular effects but the available evidence is not sufficient to distinguish the effect of BC (or EC) from that of PM2.5 mass.

Venous thrombosis and congenital absence of inferior vena cava in a patient with menorrhagia and pelvic pain.

BACKGROUND: Agenesis of the inferior vena cava (IVC) is an uncommon congenital vascular malformation. We report a case in a teenage female recently started on oral contraception. CASE: Because of menorrhagia, the patient had begun an oral contraceptive pill (OCP) 1(1/2) months prior to presentation. She initially presented with pelvic and lower back pain, and imaging showed a pelvic deep venous thrombosis (DVT) and an interrupted IVC. Anticoagulation was started, the OCP was discontinued, and a discussion occurred regarding the treatment options for her menorrhagia following her recent diagnosis. SUMMARY AND CONCLUSION: The case presented shows the rare occurrence of the congenital absence of an IVC with pelvic thrombosis in a young female with a history of menorrhagia and new onset of pelvic pain. The evaluation of this case report leads to a comprehensive review in the treatment choice for menorrhagia with the preceding history of a thrombotic event.

Methods for conducting systematic reviews of the evidence of effectiveness and economic efficiency of interventions to reduce injuries to motor vehicle occupants.

BACKGROUND: Motor vehicle occupant injury prevention is included in the Guide to Community Preventive Services because of the enormous health impact of these largely preventable injuries. This article describes the methods for conducting systematic literature reviews of interventions for three key injury prevention strategies: increasing child safety seat use, increasing safety belt use, and decreasing alcohol-impaired driving. METHODS: Systematic review methods follow those established for the Guide to Community Preventive Services and include: (1) recruiting a systematic review development team, (2) developing a conceptual approach for selecting interventions and for selecting outcomes that define the success of the interventions, (3) defining and conducting a search for evidence of effectiveness, (4) evaluating and summarizing the body of evidence of effectiveness, (5) evaluating other potential beneficial and harmful effects of the interventions, (6) evaluating economic efficiency, (7) identifying implementation barriers, (8) translating the strength of the evidence into recommendations, and (9) identifying and summarizing research gaps. RESULTS: The systematic review development team evaluated 13 interventions for the three strategic areas. More than 10,000 titles and abstracts were identified and screened; of these, 277 met the a priori systematic review inclusion criteria. Systematic review findings for each of the 13 interventions are provided in the accompanying articles in this supplement. CONCLUSION: The general methods established for conducting systematic reviews for the Guide to Community Preventive Services were successfully applied to interventions to reduce injuries to motor vehicle occupants.

Reviews of evidence regarding interventions to increase the use of safety belts.

BACKGROUND: The use of safety belts is the single most effective means of reducing fatal and nonfatal injuries in motor vehicle crashes. If all motor vehicle occupants consistently wore safety belts, an estimated 9553 deaths would have been prevented in 1999 alone. METHODS: The Guide to Community Preventive Services's methods for systematic reviews were used to evaluate the effectiveness of three interventions to increase safety belt use. Effectiveness was assessed on the basis of changes in safety belt use and number of crash-related injuries. RESULTS: Strong evidence was found for the effectiveness of safety belt laws in general and for the incremental effectiveness of primary safety belt laws relative to secondary laws. Strong evidence for the effectiveness of enhanced enforcement programs for safety belt laws was also found. Additional information is provided about the applicability, other effects, and barriers to implementation of these interventions. CONCLUSIONS: These reviews form the basis of the recommendations by the Task Force on Community Preventive Services presented elsewhere in this supplement. They can help decision makers identify and implement effective interventions that fit within an overall strategy to increase safety belt use.

Reviews of evidence regarding interventions to reduce alcohol-impaired driving.

BACKGROUND: Alcohol-related motor vehicle crashes are a major public health problem, resulting in 15,786 deaths and more than 300,000 injuries in 1999. This report presents the results of systematic reviews of the effectiveness and economic efficiency of selected population-based interventions to reduce alcohol-impaired driving. METHODS: The Guide to Community Preventive Services's methods for systematic reviews were used to evaluate the effectiveness of five interventions to decrease alcohol-impaired driving, using changes in alcohol-related crashes as the primary outcome measure. RESULTS: Strong evidence was found for the effectiveness of .08 blood alcohol concentration laws, minimum legal drinking age laws, and sobriety checkpoints. Sufficient evidence was found for the effectiveness of lower blood alcohol concentration laws for young and inexperienced drivers and of intervention training programs for servers of alcoholic beverages. Additional information is provided about the applicability, other effects, and barriers to implementation of these interventions. CONCLUSION: These reviews form the basis of the recommendations by the Task Force on Community Preventive Services presented elsewhere in this supplement. They can help decision makers identify and implement effective interventions that fit within an overall strategy to prevent impaired driving.

Changing public behavior for better health: is education enough?

While education programs are essential for changing public health behavior, they are not sufficient. Examples drawn from campaigns to reduce drunk driving and to increase the use of child safety seats, seat belts, and motorcycle helmets illustrate how education--both public information and more formalized education--can help catalyze other actions. However, by itself, education has not generally resulted in significant changes in the behaviors targeted. On the other hand, education of the public and advocacy groups has often helped enact necessary legislation. This sequence has frequently resulted in major behavioral changes. Even in such cases, however, when enforcement is inconsistent, public compliance frequently decreases. Education is an important first step in changing public behavior for better health.

Comparison of polyadenylic acid and oligouridylic acid messenger RNA associated proteins.

Various subclasses of messenger ribonucleoprotein particles were prepared from free cytoplasmic and polysome fractions of rat liver on the basis of the homopolymeric content of the constituent RNA's. Two major proteins were evident in the free cytoplasmic preparations: the poly(A)-binding protein was the major constituent of polyadenylated components and a 60 kilodalton protein was the major protein in oligouridylated components. In addition to the poly(A)-binding protein, the polysome fractions contained a 74 kilodalton protein that was present in all subclasses of particles. With both free cytoplasmic and polysome preparations, chromatography on columns of poly(U)-sepharose separated poly-adenylated mRNP's largely on the basis of the length of the poly(A) tract; mRNP's containing short poly(A) tracts (fragment distribution centered on 34 residues) were not retained by the columns, presumably because of the interaction of the poly(A) with poly(A)-binding protein.

Molecular genetic approaches to the study of the nervous system.

Disorders primarily affecting the nervous system comprise approximately one third of all established Mendelian genetic diseases in man. Recombinant DNA technology provides new approaches to the diagnosis and elucidation of the molecular pathology of these disorders. For a small but increasing number of disorders the DNA sequence coding for the involved protein has been used to define the precise molecular defect. An example is the Lesch-Nyhan syndrome. In many other situations, DNA fragments located near to the mutant gene can be used in family linkage studies to determine who is likely to have inherited the abnormal allele(s). Examples include Duchenne muscular dystrophy, Huntington's disease, and phenylketonuria. This technology offers unique opportunities to investigate the function of the nervous system in health and disease and will have a major impact on the neurosciences and the practice of clinical neurology.

A modified nucleotide in the poly(A) tract of maize RNA.

poly(A)+ RNA was isolated from maize by affinity chromatography on columns of oligo(dT)-cellulose. A modified nucleotide ('X') was detected in ribonuclease T2 digests of the RNA as part of a resistant dinucleotide. The dinucleotide was detected by means of the polynucleotide kinase-mediated transfer of a radioactive phosphate atom from adenosine triphosphate to the 5'-OH position of the dinucleotide. Intact poly(A) tracts were released from poly(A)+ RNA by digestion with ribonuclease T1 and A in a high salt buffer and were isolated by oligo(dT)-cellulose chromatography. The poly(A) preparation was found to consist of a series of polyadenylate fragments which varied in chain length from approximately 17 to greater than 70. The modified nucleotide was shown to occupy an internal position in these poly(A) tracts.

The modified nucleotide constituents of human prostatic cancer cell (MA-160) poly(A)-containing RNA.

Cytoplasmic poly A(+) RNA from human prostatic cancer cells grown in the presence of 32P was isolated by affinity chromatography on columns of oligo(dT)-cellulose. The RNA was digested with RNAase T2 and the products of digestion were fractionated by two-dimensional electrophoresis. The resulting autoradiograms revealed the presence of many different cap groups as well as two internal modified nucleotide components. 19 different type 1 and type 2 'cap' groups were identified. The internal modified nucleotides were N6-methyl adenosine and a 2'-O-methyl nucleotide possessing an unusual modified base.

'Cap' structures in maize poly(A)-containing RNA.

Poly(A)-containing RNA was isolated from maize embryos by chromatography on columns of oligo(dT)-cellulose and exhaustively digested with ribonucleases T2, T1, and A. Fractionation of the digests by two-dimensional electrophoresis revealed the presence of three 7-methylguanosine-terminated 'cap structures' of the type m7GpppNp.

S1 nuclease as a probe of yeast ribosomal 5 S RNA conformation.

5 S RNA was isolated from Saccharomyces cerevisiae grown in the presence of 32P-phosphate and digested with nuclease S1, a single-strand specific nuclease. Two different procedures were employed to determine the sites of attack on the RNA. First, 5 S RNA was isolated from nuclease S1 digests, digested to completion with ribonuclease T1, and then 'fingerprinted' by two-dimensional electrophoresis. Quantitation of each of the characteristic RNAase T1-derived oligonucleotides was employed to determine the relative susceptibility of various regions of the molecule to nuclease S1. A second procedure to define nuclease S1-susceptible sites in the molecule employed polyacrylamide gel electrophoretic fractionation of nuclease S1 digests followed by identification of the nucleotide sequences of the released RNA fragments. Both procedures showed that the region of the molecule between residues 9 and 60 was most susceptible to nuclease S1, with preferential cleavage occurring between residues 12-25 and 50-60. These results are discussed in relation to a proposed model for the secondary structure of yeast 5 S RNA.