EPA: Highlights of the Child-Specific Exposure Factors Handbook

EPA: Highlights of the Child-Specific Exposure Factors Handbook
http://www.epa.gov/childexpfactors/highlights

NIOSH Respirator Trusted-Source Information Page

The Respirator Trusted-Source Information Page may be viewed at:

www.cdc.gov/niosh/npptl/topics/respirators/disp_part/RespSource.html

CDC Vision Health Initiative Website

Announcement: Vision Health Initiative Website

CDC has created a new Vision Health Initiative website with information regarding vision and eye health, projects with diverse
stakeholders, journal publications and reports, and vision health--related resources for professionals and consumers. The website
includes an interactive map displaying state-specific vision and eye health statistics. With this tool, states that use the Behavioral Risk Factor Surveillance System visual impairment and access to eye care module can produce reports and presentations with data specific to their states. The website can be accessed at http://www.cdc.gov/visionhealth.

In 2004, approximately 3.3 million persons aged ?40 years had blindness or visual impairment; this number is predicted to double by 2030 because of increases in diabetes and other chronic diseases and aging of the U.S. population (1). With early detection and treatment, half of all blindness can be prevented or reversed (2).

References

1. Prevent Blindness America. Vision problems in the U.S. 2008 update to the fourth edition. Available at
http://www.preventblindness.org/vpus. Accessed October 29, 2009.

2. Sommer A, Tielsch JM, Katz J, et al. Racial differences in the cause-specific prevalence of blindness in east Baltimore. N Engl J Med 1991;325:1412--7

Surgical Mask vs N95 Respirator for Preventing Influenza Among Health Care Workers: A Randomized Trial [Original Contribution]

Surgical Mask vs N95 Respirator for Preventing Influenza Among Health Care Workers: A Randomized Trial [Original Contribution]: "

Context Data about the effectiveness of the surgical mask compared with the N95 respirator for protecting health care workers against influenza are sparse. Given the likelihood that N95 respirators will be in short supply during a pandemic and not available in many countries, knowing the effectiveness of the surgical mask is of public health importance.

Objective To compare the surgical mask with the N95 respirator in protecting health care workers against influenza.

Design, Setting, and Participants Noninferiority randomized controlled trial of 446 nurses in emergency departments, medical units, and pediatric units in 8 tertiary care Ontario hospitals.

Intervention Assignment to either a fit-tested N95 respirator or a surgical mask when providing care to patients with febrile respiratory illness during the 2008-2009 influenza season.

Main Outcome Measures The primary outcome was laboratory-confirmed influenza measured by polymerase chain reaction or a 4-fold rise in hemagglutinin titers. Effectiveness of the surgical mask was assessed as noninferiority of the surgical mask compared with the N95 respirator. The criterion for noninferiority was met if the lower limit of the 95% confidence interval (CI) for the reduction in incidence (N95 respirator minus surgical group) was greater than –9%.

Results Between September 23, 2008, and December 8, 2008, 478 nurses were assessed for eligibility and 446 nurses were enrolled and randomly assigned the intervention; 225 were allocated to receive surgical masks and 221 to N95 respirators. Influenza infection occurred in 50 nurses (23.6%) in the surgical mask group and in 48 (22.9%) in the N95 respirator group (absolute risk difference, –0.73%; 95% CI, –8.8% to 7.3%; P = .86), the lower confidence limit being inside the noninferiority limit of –9%.

Conclusion Among nurses in Ontario tertiary care hospitals, use of a surgical mask compared with an N95 respirator resulted in noninferior rates of laboratory-confirmed influenza.

Trial Registration clinicaltrials.gov Identifier: NCT00756574

Published online October 1, 2009 (doi:10.1001/jama.2009.1466).

"

Self-paced exercise is less physically challenging than enforced constant pace exercise of the same intensity: influence of complex central metabolic

Self-paced exercise is less physically challenging than enforced constant pace exercise of the same intensity: influence of complex central metabolic control:

"Objective: To examine whether self-pacing reduces the physiological challenge of performing 5000 m rowing ergometry exercise in comparison with a matched-intensity exercise condition in which a constant effort pacing strategy is enforced.

Methods: Nine healthy well-trained male participants volunteered to participate in three 5000 m rowing conditions (two submaximal and one maximal conditions) in an individualised order. In the submaximal conditions, participants were required to (1) perform 5000 m at a constant rating of perceived exertion (RPE 15-Hard) (SubRPE) or (2) perform 5000 m at an enforced constant pace equivalent to the mean power output (PO) of the SubRPE condition (SubEXT). A maximal condition (MaxTT) was included to disguise the purpose of the study and to facilitate an element of randomisation in the test sequence. Dynamic intratest responses were assessed every 30s: PO, Vo₂, iEMG, core (T_c) and skin temperatures (T_sk).

Results: There was no difference between performance times of the two submaximal trials. The mean PO represented 83.83 (SD 8.88)% (SubRPE) and 83.40 (8.84)% (SubEXT) of the mean MaxTT power output. T_c (SubRPE:38.46 (0.23)°C, SubEXT:38.72 (0.36)°C; p<0.01), post-test BLa (SubRPE:5.24 (2.18), SubEXT:6.19 (2.51) mmol/l; p<0.05) and iEMG (p<0.05) were significantly elevated in SubEXT compared with SubRPE. There were no differences in the dynamics of HR or Vo₂ between SubEXT and SubRPE. The intratest stroke-to-stroke variability of power output was significantly greater in the SubRPE condition compared with SubEXT (p<0.01).

Conclusions: Enforced constant paced exercise presents a significantly greater physiological challenge than self-paced exercise. The ability to dynamically self-pace effort via manipulations of power output during exercise is an important behavioural response to homeostatic challenges and thus forms an integral part of a complex central regulatory process.
"

Effect of taping on the shoulders of Australian football players

Effect of taping on the shoulders of Australian football players:

"Background: Taping of the shoulder is common in many sports, particularly Australian football, a contact sport that often involves marking (catching) the ball overhead and has a high incidence of shoulder instability.

Hypothesis: Taping of the shoulder reduces glenohumeral joint laxity and improves proprioception without impairing function.

Study design: Crossover study design.

Methods: 33 male players aged 18–31 years were recruited from a local Australian football club. The dominant shoulder of each player was tested with and without taping in a randomised fashion by an examiner blinded to the presence or absence of taping. The tests were (1) inferior glenohumeral joint laxity (the Orthopaedic Research Institute laxometer), (2) shoulder joint position sense accuracy using an optical tracking system, and (3) handballing accuracy.

Results: The methods for testing laxity and joint position sense had good intraobserver reliability and sensitivity. All subjects tolerated the taping and testing. Glenohumeral joint laxity (p = 0.75), joint position sense (p = 0.56) and handballing accuracy (p = 0.6) were not changed by taping.

Conclusions: Taping of the shoulder joint in uninjured and non-symptomatic Australian football players in a pattern that attempted not to restrict their range of overhead movement did not significantly affect the accuracy of joint position sense, inferior laxity or handball accuracy.

Clinical relevance: These data suggest that taping of the shoulder is unlikely to decrease the incidence of injury—specifically dislocation—of the shoulder in Australian football players.
"

Would you dope? A general population test of the Goldman dilemma

Would you dope? A general population test of the Goldman dilemma:

"Objective: To test Goldman's dilemma on a general population sample by asking whether they would take the Faustian bargain of a drug that guaranteed sporting success but would result in their death in 5 years' time. Between 1982 and 1995 a bi-annual survey using this dilemma suggested half of all elite athletes would take the drug.

Design: A random telephone survey of 250 members of the Australian general public, with counterbalanced presentation of success and death.

Main outcome measures: Respondents gave age, gender, sports engagement and response to the dilemma (yes/no).

Results: Only two of a sample of 250 reported they would take the bargain offered by the dilemma.

Conclusions: Athletes differ markedly from the general population in response to the dilemma. This raises significant practical and ethical dilemmas for athlete support personnel. The psychometry of the dilemma needs to be established more comprehensively for general and athlete populations.
"

Non-steroidal anti-inflammatory drugs in sports medicine: guidelines for practical but sensible use

Non-steroidal anti-inflammatory drugs in sports medicine: guidelines for practical but sensible use: "Introduction:

Non-steroidal anti-inflammatory drugs (NSAID) are commonly used in sports medicine. NSAID have known anti-inflammatory, analgesic, antipyretic and antithrombotic effects, although their in-vivo effects in treating musculoskeletal injuries in humans remain largely unknown. NSAID analgesic action is not significantly greater than paracetamol for musculoskeletal injury but they have a higher risk profile, with side-effects including asthma exacerbation, gastrointestinal and renal side-effects, hypertension and other cardiovascular diseases.

Discussion:

The authors recommend an approach to NSAID use in sports medicine whereby simple analgesia is preferentially used when analgesia is the primary desired outcome. However, based both on the current pathophysiological understanding of most injury presentations and the frequency that inflammation may actually be a component of the injury complex, it is premature to suppose that NSAID are not useful to the physician managing sports injuries. The prescribing of NSAID should be cautious and both situation and pathology specific. Both dose and duration minimisation should be prioritised and combined with simple principles of protection, rest, ice, compression, elevation (PRICE), which should allow NSAID-sparing. NSAID use should always be coupled with appropriate physical rehabilitation.

Conclusion:

NSAID are probably most useful for treating nerve and soft-tissue impingements, inflammatory arthropathies and tenosynovitis. They are not generally indicated for isolated chronic tendinopathy, or for fractures. The use of NSAID in treating muscle injury is controversial. Conditions in which NSAID use requires more careful assessment include ligament injury, joint injury, osteoarthritis, haematoma and postoperatively.

"

Does occupational success influence longevity among England test cricketers?

Does occupational success influence longevity among England test cricketers?:

"Objective: To determine whether the longevity of England test cricketers is influenced by occupational success, controlling for the influence of social background.
Design: Archival survey.

Setting: England.

Subjects: Those 418 cricketers who played for England in a test match from the first test in 1876 to 1963 when the distinction between amateur and professional status was removed.

Main outcome measures: Length of life.

Results: Survival analysis of players born between 1827 and 1941 (349 dead, 69 alive) showed a significant relation between mortality and year of birth (p<0.001), amateur/professional status (p = 0.042) and the number of test matches played (p = 0.042). Captaining England was not related to survival.

Conclusion: The link between longevity and both social background and occupational success is supported among test match cricketers. Amateur (or 'gentlemen') cricketers from more privileged social backgrounds survived longer than professionals (or 'players'). The most successful cricketers who played in a larger number of tests lived longer than those who played in a smaller number of tests. Captaining England, which could be regarded as a form of occupational 'control', was not associated with longevity.
"

Central aponeurosis tears of the rectus femoris: practical sonographic prognosis

Central aponeurosis tears of the rectus femoris: practical sonographic prognosis: "Objective:

This study is a statistical analysis to establish whether a correlation exists between the level and degree of rectus femoris (RF) central tendon injury and the amount of time that an athlete is unable to participate subsequently, referred to as 'sports participation absence' (SPA).

Design: Causal–comparative study.

Patients: 35 players from two high-level Spanish soccer teams with an injury to the central tendon of the RF based on clinical and ultrasound criteria.

Main Outcome Measure: Ultrasound examination was performed with an 8–2 MHz linear multifrequency transducer. All studies included both longitudinal and transverse RF sections.

Results: At the proximal level the SPA time is 45.1 days when the injury length is 4.0 cm. This value increases by 5.3 days with each 1 cm increase in the length of injury. In the case of distal level injury, SPA time is 32.9 days when the injury length is 3.9 cm. This value increases by 3.4 days with each 1 cm increase. In the total representative sample, SPA time when the injury length is 4.2 cm corresponds to 39.1 days. This value increases by 4.2 days per length unit.

Conclusions: RF central tendon injury at the proximal level is associated with a greater SPA time than at the distal level. Patients with a grade II injury have an SPA time longer than those with a grade I injury whether the injury is located proximal or distal.
"

ORIGINAL INVESTIGATION: Evaluating the Incremental Benefits of Raising High-Density Lipoprotein Cholesterol Levels During Lipid Therapy After Adjustme

ORIGINAL INVESTIGATION: Evaluating the Incremental Benefits of Raising High-Density Lipoprotein Cholesterol Levels During Lipid Therapy After Adjustment for the Reductions in Other Blood Lipid Levels: "

Background The role of high-density lipoprotein cholesterol (HDL-C) as a therapeutic target to prevent cardiovascular (CV) events remains unclear. We examined data from the Framingham Offspring Study from 1975 through 2003 to determine whether increases in HDL-C levels after lipid therapy was started were independently associated with a reduction in CV events.

Methods Using Cox proportional-hazards regression, we evaluated the risk of a CV event associated with changes in blood lipid levels among individuals who started lipid therapy. The independent effect of HDL-C levels on future CV risk (average follow-up, 8 years) was estimated after adjustment for changes in low-density lipoprotein cholesterol, plasma triglycerides, and pretreatment blood lipid levels. Potential confounders (eg, smoking status, weight, and the use of β-blockers) were then added to the model. Interactions between blood lipid levels were also explored.

Results The change in HDL-C level was a strong independent risk factor for CV events (hazard ratio, 0.79 per 5-mg/dL increase; 95% confidence interval, 0.67-0.93) after adjustment for the other lipid changes associated with treatment. This relationship remained stable across a wide range of patient subgroups and did not appear to be associated with a specific drug class. An important interaction was observed: the lower the pretreatment low-density lipoprotein cholesterol level, the greater the impact of raising the HDL-C.

Conclusions Raising HDL-C levels with commonly used lipid medications appears to be an important determinant of the benefits associated with lipid therapy. These results support the further evaluation of therapies to raise HDL-C levels to prevent CV events.

"

ORIGINAL CONTRIBUTION: Surgical Mask vs N95 Respirator for Preventing Influenza Among Health Care Workers: A Randomized Trial

ORIGINAL CONTRIBUTION: Surgical Mask vs N95 Respirator for Preventing Influenza Among Health Care Workers: A Randomized Trial: "

Context Data about the effectiveness of the surgical mask compared with the N95 respirator for protecting health care workers against influenza are sparse. Given the likelihood that N95 respirators will be in short supply during a pandemic and not available in many countries, knowing the effectiveness of the surgical mask is of public health importance.

Objective To compare the surgical mask with the N95 respirator in protecting health care workers against influenza.

Design, Setting, and Participants Noninferiority randomized controlled trial of 446 nurses in emergency departments, medical units, and pediatric units in 8 tertiary care Ontario hospitals.

Intervention Assignment to either a fit-tested N95 respirator or a surgical mask when providing care to patients with febrile respiratory illness during the 2008-2009 influenza season.

Main Outcome Measures The primary outcome was laboratory-confirmed influenza measured by polymerase chain reaction or a 4-fold rise in hemagglutinin titers. Effectiveness of the surgical mask was assessed as noninferiority of the surgical mask compared with the N95 respirator. The criterion for noninferiority was met if the lower limit of the 95% confidence interval (CI) for the reduction in incidence (N95 respirator minus surgical group) was greater than –9%.

Results Between September 23, 2008, and December 8, 2008, 478 nurses were assessed for eligibility and 446 nurses were enrolled and randomly assigned the intervention; 225 were allocated to receive surgical masks and 221 to N95 respirators. Influenza infection occurred in 50 nurses (23.6%) in the surgical mask group and in 48 (22.9%) in the N95 respirator group (absolute risk difference, –0.73%; 95% CI, –8.8% to 7.3%; P = .86), the lower confidence limit being inside the noninferiority limit of –9%.

Conclusion Among nurses in Ontario tertiary care hospitals, use of a surgical mask compared with an N95 respirator resulted in noninferior rates of laboratory-confirmed influenza.

Trial Registration clinicaltrials.gov Identifier: NCT00756574

Published online October 1, 2009 (doi:10.1001/jama.2009.1466).

"

A comparison of sodium calcium edetate (edetate calcium disodium) and succimer (DMSA) in the treatment of inorganic lead poisoning

A comparison of sodium calcium edetate (edetate calcium disodium) and succimer (DMSA) in the treatment of inorganic lead poisoning

Introduction. This article reviews the experimental and clinical studies that have compared the efficacy (impact on urine lead excretion, blood and tissue lead concentrations, resolution of features and survival) of sodium calcium edetate (edetate calcium disodium) and succimer (DMSA) in the treatment of inorganic lead poisoning. It also summarizes the pharmacokinetic and pharmacodynamic aspects and the adverse effects of treatment.

Methods. Medline, Toxline, and Embase were searched for all available years to June 2009.

Pharmacokinetics and pharmacodynamics. The absorption of oral DMSA is more complete than sodium calcium edetate; the latter has to be administered parenterally. Both antidotes are distributed predominantly extracellularly. Sodium calcium edetate is not metabolized, whereas DMSA is extensively metabolized to mixed disulfides of cysteine. The two antidotes have elimination half-lives of less than 60 min. There is no evidence that either antidote crosses the blood-brain barrier to any major extent. Sodium calcium edetate chelates lead by displacement of the central Ca²⁺ ion with Pb²⁺. The nature of the DMSA-lead chelate is less clearly defined. There is evidence that the mixed disulfides of cysteine are the active chelating moiety in humans. If this is the case, this suggests that chelation occurs principally, if not exclusively, in the kidney. The primary source of lead mobilized by sodium calcium edetate is bone with an additional contribution from kidney and liver.

Efficacy. Comparison of the experimental studies is complicated by substantial variations in study design, particularly the antidote dose, the route and duration of treatment, the amount and duration of lead dosing, and lack of direct comparison between antidotes (comparison was usually made with control). In experimental studies that used equimolar and clinically relevant antidote doses and assessed the impact of DMSA and sodium calcium edetate on urine lead excretion and/or blood lead concentrations, similar results were found, though no direct comparison between antidotes was undertaken. DMSA was more effective than sodium calcium edetate in reducing the kidney lead concentration, sodium calcium edetate was more effective than DMSA in reducing bone lead concentrations, and there was no consistently observed effect of chelation therapy on brain lead concentrations in these experimental studies. Only two clinical studies have compared equimolar or similar antidote doses in enhancing urine lead excretion; there was no statistical difference between the antidotes, though both studies had limitations. DMSA and sodium calcium edetate had a comparable impact on lowering blood lead concentrations in a clinical study using similar molar antidote doses.

Adverse effects. Sodium calcium edetate causes dose-related nephrotoxicity. Both agents deplete zinc and copper, the effect on zinc being significantly greater with sodium calcium edetate. A transient increase in hepatic transaminase activity has been reported with both antidotes but appears to be more common with DMSA and neither has been associated with clinically significant hepatic toxicity. Skin lesions during treatment with sodium calcium edetate are unusual and have been attributed to zinc deficiency. DMSA has occasionally been associated with a severe mucocutaneous reaction necessitating discontinuation of therapy.

Conclusions. Oral DMSA and parenteral sodium calcium edetate are both effective chelators of lead. There are currently insufficient data, however, to conclude that either antidote is superior in enhancing lead excretion. Both antidotes resolve the symptoms of moderate and severe lead toxicity rapidly. Although there is greater clinical experience with sodium calcium edetate, particularly in the treatment of lead encephalopathy, oral DMSA may now be considered as an alternative in circumstances where oral therapy is preferable.

Are calcium oxalate crystals involved in the mechanism of acute renal failure in ethylene glycol poisoning?

Are calcium oxalate crystals involved in the mechanism of acute renal failure in ethylene glycol poisoning?

Introduction. Ethylene glycol (EG) poisoning often results in acute renal failure, particularly if treatment with fomepizole or ethanol is delayed because of late presentation or diagnosis. The mechanism has not been established but is thought to result from the production of a toxic metabolite.

Methods. A literature review utilizing PubMed identified papers dealing with renal toxicity and EG or oxalate. The list of papers was culled to those relevant to the mechanism and treatment of the renal toxicity associated with either compound.

Role of metabolites. Although the “aldehyde” metabolites of EG, glycolaldehyde, and glyoxalate, have been suggested as the metabolites responsible, recent studies have shown definitively that the accumulation of calcium oxalate monohydrate (COM) crystals in kidney tissue produces renal tubular necrosis that leads to kidney failure. In vivo studies in EG-dosed rats have correlated the severity of renal damage with the total accumulation of COM crystals in kidney tissue. Studies in cultured kidney cells, including human proximal tubule (HPT) cells, have demonstrated that only COM crystals, not the oxalate ion, glycolaldehyde, or glyoxylate, produce a necrotic cell death at toxicologically relevant concentrations. COM crystal accumulation.In EG poisoning, COM crystals accumulate to high concentrations in the kidney through a process involving adherence to tubular cell membranes, followed by internalization of the crystals.

Mechanism of toxicity. COM crystals have been shown to alter membrane structure and function, to increase reactive oxygen species and to produce mitochondrial dysfunction. These processes are likely to be involved in the mechanism of cell death.

Conclusions. Accumulation of COM crystals in the kidney is responsible for producing the renal toxicity associated with EG poisoning. The development of a pharmacological approach to reduce COM crystal adherence to tubular cells and its cellular interactions would be valuable as this would decrease the renal toxicity not only in late treated cases of EG poisoning, but also in other hyperoxaluric diseases such as primary hyperoxaluria and kidney stone formation.

Vital Signs: Perceptions: What Clown? I Was Talking With My Mom

Vital Signs: Perceptions: What Clown? I Was Talking With My Mom: "In a study, a man in an outlandish outfit on a unicycle was not enough to draw the notice of many cellphone users.


How much do you miss when you are talking on a cell phone?

Researchers at Western Washington University decided to study whether pedestrians engrossed in a phone conversation would notice obvious events around them. “I was trying to think about what kind of distraction we could put out there, and I talked to this student who had a unicycle,” said Ira E. Hyman Jr., a professor ofpsychology. “He said, ‘What’s more, I own a clown suit.’ You don’t have a student who unicycles in a clown suit every day, so you have to take advantage of these things.”

The student, Dustin Randall, donned the suit — purple and yellow, with polka-dot sleeves, red shoes and a red nose — then hopped on the unicycle and pedaled around a square. After pedestrians crossed the square, researchers asked them, “Did you see anything unusual?”

Among pedestrians who were listening to music or walking alone, 1 in 3 replied that they had just seen a clown on a unicycle, according to a report on the study, in the journal Applied Cognitive Psychology. Nearly 60 percent of those who were walking with a friend mentioned the clown. But among people who had been talking on a cellphone, the figure was 8 percent.

When the pedestrians were asked, “Did you see the unicycling clown?” the rates rose — to as high as 71 percent for people walking with a friend. But among those who had been talking on a cellphone, just 25 percent said they had. TARA PARKER-POPE"