Isotopic Characterization of Atmospheric Gaseous Elemental Mercury by Passive Air Sampling.

Tracing emission sources and transformations of atmospheric mercury with Hg stable isotopes depends on the ability to collect amounts sufficient for reliable quantification. Commonly employed active sampling methods require power and long pumping times, which limits the ability to deploy in remote locations and at high spatial resolution and can lead to compromised traps. In order to overcome these limitations, we conducted field and laboratory experiments to assess the preservation of isotopic composition during sampling of gaseous elemental mercury (GEM) with a passive air sampler (PAS) that uses a sulfur-impregnated carbon sorbent and a diffusive barrier. Whereas no mass independent fractionation (MIF) was observed during sampling, the mass dependent fractionation (MDF, δ202Hg) of GEM taken up by the PAS was lower than that of actively pumped samples by 1.14 ± 0.24‰ (2SD). Because the MDF offset was consistent across field studies and laboratory experiments conducted at 5, 20, and 30 °C, the PAS can be used for reliable isotopic characterization of GEM (±0.3‰ for MDF, ±0.05‰ for MIF, 2SD). The MDF offset occurred more during the sorption of GEM rather than during diffusion. PAS field deployments confirm the ability to record differences in the isotopic composition of GEM (i) with distance from point sources and (ii) sampled at different background locations globally.

Evidence of transboundary mercury and other pollutants in the Puyango-Tumbes River basin, Ecuador-Peru.

In Portovelo in southern Ecuador, 87 gold processing centers along the Puyango-Tumbes River produce an estimated 6 tonnes of gold per annum using a combination of mercury amalgamation and/or cyanidation and processing poly-metallic ores. We analysed total Hg, Hg isotopes, total arsenic, cadmium, copper, lead and zinc in water and sediment along the Puyango in 2012-2014. The highest total mercury (THg) concentrations in sediments were found within a 40 km stretch downriver from the processing plants, with levels varying between 0.78-30.8 mg kg-1 during the dry season and 1.80-70.7 mg kg-1 during the wet season, with most concentrations above the CCME (Canadian Council of Ministers of the Environment) Probable Effect Level (PEL) of 0.5 mg kg-1. Data from mercury isotopic analyses support the conclusion that mercury use during gold processing in Portovelo is the source of Hg pollution found downstream in the Tumbes Delta in Peru, 160 km away. The majority of the water and sediment samples collected from the Puyango-Tumbes River had elevated concentrations of, arsenic, cadmium, copper, lead and zinc exceeding the CCME thresholds for the Protection of Aquatic Life. At monitoring points immediately below the processing plants, total dissolved concentrations of these metals exceeded the thresholds by 156-3567 times in surface waters and by 19-740 times in sediment. The results illustrate a significant transboundary pollution problem involving Hg and other toxic metals, amplified by the fact that the Puyango-Tumbes River is the only available water source in the semi-arid region of northern Peru.

Current status of nonsteroidal anti-inflammatory drugs in physiatry: balancing risks and benefits in pain management.

The gastropathy associated with the administration of nonsteroidal anti-inflammatory drugs (NSAIDs) for musculoskeletal pain disorders has contributed to significant morbidity and mortality. The distinction between the cyclooxygenase 1 and 2 enzymatic properties lead to the development of selective cyclooxygenase-2 inhibitory NSAIDs with the prospect of reducing NSAID-related gastropathy while maintaining anti-inflammatory properties. Initial studies of the efficacy and safety of the selective cyclooxygenase-2 inhibitors seemed promising. Larger clinical trials were carried out to reinforce the efficacy and safety of the cyclooxygenase-2 anti-inflammatory medications (coxibs). Further analysis of these trials raised concern with regard to both the efficacy and safety of this class of drugs. The most recent clinical trials of the coxibs have demonstrated significant cardiovascular thrombogenic potential, particularly at higher doses. Clinical investigators and regulatory agencies have questioned whether these findings mitigate the efficacy of coxibs and NSAIDs in general in the prophylaxis of colonic polyps, Alzheimer's disease, and more saliently, musculoskeletal pain disorders. This article addresses the current controversy of the efficacy and safety of the coxibs and NSAIDs in general based on recent clinical trials and review by healthcare consortiums. This article also provides guidelines regarding the use of NSAIDs, including the diminishing armamentarium of the coxibs, and the alternative therapeutic options available to the physiatrist in managing musculoskeletal pain disorders.

Rehabilitation of orthopedic and rheumatologic disorders. 1. Osteoporosis assessment, treatment, and rehabilitation.

UNLABELLED: This self-directed learning module highlights a clinical vignette of a female patient with osteoporosis and addresses the clinical presentation, assessment, medical management, and rehabilitation approaches to a patient with an acute vertebral fracture. It is part of the study guide on osteoporosis in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This chapter emphasizes the differential diagnosis, clinical diagnostic considerations, current pharmacotherapy, invasive procedure options, and orthotic and exercise interventions for a patient with postmenopausal osteoporosis. OVERALL ARTICLE OBJECTIVE: To summarize the clinical evaluation, medical management, and rehabilitation strategies in women with postmenopausal osteoporosis and acute vertebral fracture presentation.

Rehabilitation of orthopedic and rheumatologic disorders. 2. Osteoarthritis assessment, treatment, and rehabilitation.

UNLABELLED: This self-directed learning module discusses a patient with knee osteoarthritis and addresses the clinical presentation, assessment, medical management, rehabilitation approaches, and surgical options. It is part of the chapter on osteoarthritis in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This chapter emphasizes the differential diagnosis, clinical diagnostic considerations, current pharmacology, orthotics, exercise interventions, and surgical procedure options for a patient with knee osteoarthritis. OVERALL ARTICLE OBJECTIVE: To summarize diagnostic considerations and management of knee osteoarthritis.

Rehabilitation of orthopedic and rheumatologic disorders. 3. Total hip arthroplasty rehabilitation.

UNLABELLED: This self-directed learning module highlights a clinical vignette of a female patient who had a total hip arthroplasty. The module addresses the medical management and rehabilitation interventions necessary to direct the postacute care needs of this patient. It is part of the study guide on rehabilitation of the joint replacement patient in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This chapter emphasizes planning for discharge from the acute care hospital, postacute care medical complications, and rehabilitation program elements germane to the patient with hip joint replacement. OVERALL ARTICLE OBJECTIVE: To summarize the postacute care planning, medical complications, and rehabilitation needs of the patient with hip joint replacement.

Rehabilitation of orthopedic and rheumatologic disorders. 4. Rheumatoid arthritis and calcium pyrophosphate deposition disease.

UNLABELLED: This self-directed learning module highlights a clinical vignette of 2 patients: (1) a woman with bilateral, distal, upper-limb pain assessed by differential diagnosis, laboratory work-up, and treatment of rheumatologic disorders frequently seen in the physiatric practice setting and (2) a 57-year-old man with an acute recurring monoarthritis of the knee and addresses clinical presentation, assessment, medical management, and rehabilitation approaches. It is part of the chapter on rehabilitation of orthopedic and rheumatologic disorders in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article specifically focuses on 2 aspects: (1) the differential diagnosis of polyarthralgia, distal upper-limb pain, criteria for classification of rheumatoid arthritis, synovial fluid analysis, and comprehensive treatment of rheumatoid arthritis, both pharmacologic and nonpharmacologic and (2) the differential diagnosis, clinical diagnostic considerations, current pharmacotherapy, invasive procedure options, and orthotic and exercise interventions for a patient with calcium pyrophosphate dehydrate-induced monoarthritis of the knee. OVERALL ARTICLE OBJECTIVES: (a) Clinical evaluation, diagnosis, management, and rehabilitation strategies in persons with initial presentations of inflammatory distal upper-limb pain and (b) clinical evaluation of an individual with crystal-induced monoarthritis and differentiation of the pathophysiology, assessment, and treatment of chondrocalcinosis.

Rehabilitation of orthopedic and rheumatologic disorders. 5. Lumbar spinal stenosis.

UNLABELLED: This self-directed learning module highlights the pathoanatomy and pathogenesis of lumbar spinal stenosis. The areas covered include assessment and therapeutic options in the rehabilitation of patients with degenerative lumbar spinal stenosis. It is part of the study guide on rehabilitation of orthopedic and rheumatologic disorders in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. OVERALL ARTICLE OBJECTIVES: (a) To summarize the evaluation and management of lumbar spinal stenosis and (b) to review the pathoanatomy and pathogenesis of lumbar degenerative spinal stenosis.

Multivariate analysis of the factors affecting duration of acute inpatient rehabilitation after hip and knee arthroplasty.

OBJECTIVE: To determine which factors predict length of stay at a rehabilitation hospital for total hip and knee arthroplasty patients. DESIGN: Length of stay at an acute rehabilitation hospital was analyzed with respect to demographic, surgical, and comorbidity factors using univariate and multivariate statistical techniques. Data were retrospectively collected of 808 hip and knee arthroplasty rehabilitation patients from years 2000 and 2001 at a large, urban, university-affiliated acute rehabilitation hospital. Demographic factors included age, insurance, marital status, sex, race, and body mass index. Surgical factors included knee/hip arthroplasty, unilateral/bilateral arthroplasty, and indication for surgery. Also, the 22 most prevalent comorbid illnesses for the patient group were analyzed for their association with length of stay. RESULTS: Significant factors for predicting length of stay were indication for surgery, number of comorbid illnesses, unmarried marital status, and black race. Also, advanced age and male sex approached significance. CONCLUSION: Length of stay in rehabilitation for total hip arthroplasty and total knee arthroplasty can be statistically modeled using various factors. These findings will help clinicians address prolonged length of stay and resource allocation issues.

Effectiveness of a lateral-wedge insole on knee varus torque in patients with knee osteoarthritis.

OBJECTIVES: To test whether a lateral-wedged insole, inclined at 5 degrees or 10 degrees, significantly reduces knee varus torque during walking in patients with knee osteoarthritis compared with both using no insole and with wearing nonwedged control insoles of the same material and average thickness. DESIGN: Patients with medial knee osteoarthritis were studied while they walked wearing their comfortable shoes (1) without an insole; (2) with a 5 degrees lateral wedge compared with a nonwedged, 3.175-mm (1/8-in) even-thickness control insole; and (3) with a 10 degrees lateral wedge compared with a nonwedged 6.35-mm ((1/4)-in) even-thickness control insole. SETTING: A gait laboratory with 3-dimensional motion analysis and force platform equipment. PARTICIPANTS: Fifteen patients with clinical and radiographic osteoarthritis of the medial compartment of 1 knee. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Peak external knee varus torques during the stance period of gait. Data regarding lower-extremity joint torques and motions were collected, and knee joint torques using the different insoles and wedges were compared by analysis of variance. RESULTS: Although responses varied among individuals, as a group, both the 5 degrees and 10 degrees lateral-wedge insoles significantly reduced the knee varus torque during walking compared with walking with no insole and walking with nonwedged 3.175-mm and 6.35-mm control insoles. Compared with no insole, the 5 degrees wedge reduced the peak knee varus torque values by about 6% and the 10 degrees wedge reduced the peaks by about 8%. Although there were no significant differences in speed of walking between the conditions, the 10 degrees wedge and 6.35-mm control insoles were associated with varying degrees of discomfort. CONCLUSION: Both wedge insoles are effective in reducing the varus torque during walking beyond what theoretically could be explained by a reduced walking speed or cushioning effect from the insole. These data imply that wedged insoles are biomechanically effective and should reduce loading of the medial compartment in persons with medial knee osteoarthritis. Although the effect of the 5 degrees wedge was smaller, it may be more comfortable than the 10 degrees wedge to wear inside one's own shoes.