Evaluation of postural sway and impact forces during ingress and egress of scissor lifts at elevations.

Workers are at risk when entering (ingress) or exiting (egress) elevated scissor lifts. In this study, we recorded ground impact forces and postural sway from 22 construction workers while they performed ingress and egress between a scissor lift and an adjacent work surface with varying conditions: lift opening designs, horizontal and vertical gaps, and sloped work surfaces. We observed higher peak ground shear forces when using a bar-and-chain opening, with larger horizontal gap, with the lift surface more than 0.2 m below the work surface, and presence of a sloped (26°) work surface. Similar trends were observed for postural sway, except that the influence of vertical distance was not significant. To reduce slip/trip/fall risk and postural sway of workers while ingress or egress of an elevated scissor lift, we suggest scissor lifts be equipped with a gate-type opening instead of a bar-and-chain design. We also suggest the lift surface be placed no more than 0.2 m lower than the work surface and the horizontal gap between lift and work surfaces be as small as possible. Selecting a non-sloped surface to ingress or egress a scissor lift is also preferred to reduce risk.

Trichloroethylene-induced formic aciduria in the male C57 Bl/6 mouse.

1, 1, 2-Trichloroethylene (TCE) is of environmental concern, due to evaporation while handling, chemical processing and leakage from chemical waste sites, leading to its contamination of ground water and air. For several decades there has been issues about possible long term health effects of TCE but recently the International Agency for Research on Cancer (IARC) and the US Environmental Protection Agency classified TCE as a human carcinogen. Links having been established between occupational exposures and kidney cancer and possible links to non-Hodgkin lymphoma and liver cancer, but there is more still more to learn. In male rats, TCE produces a small increase in the incidence of renal tubule tumours but not in female rats or mice of either sex. However, chronic renal injury was seen in these bioassays in both sexes of rats and mice. The mechanism of kidney injury from TCE is thought to be due to reductive metabolism forming a cysteine conjugate that is converted to a reactive metabolite via the enzyme cysteine conjugate ß-lyase. However, TCE also produces a marked and sustained formic aciduria in male rats and it has been suggested that long term exposure to formic acid could lead to renal tubule injury and regeneration. In this study we have determined if TCE produces formic aciduria in male mice following a single and repeat dosing. Male C57 Bl/6OlaHsd mice were dosed with 1000mg/kg by ip injection and urine collected overnight 24, 48, 72 and 96h after dosing. Formic acid was present in urine 24h after dosing, peaked around 48h at 8mg formic acid excreted/mouse, and remained constant over the next 24h and was not back to normal 96h after dosing. This was associated with a marked acidification of the urine. Plasma creatinine and renal pathology was normal. Plasma kinetics of formic acid showed it was readily cleared with an initial half-life of 2.42h followed by a slower rate with a half-life of 239h. Male mice were then dosed twice/week at 1000mg/kg TCE for 56days, as anticipated there was a marked and sustained formic aciduria over the duration of the study. This was associated with acidification of the urine, mild diuresis and a marked fall in urinary ammonia. Six biomarkers of renal injury KIM-1, NGAL, NAG, Cystatin-c, Albumin and IL-18 were measured in urine over time and they all showed a small increase at the later time points indicative of early markers of renal injury. However, there was no histological evidence of renal damage or renal tubule cell proliferation after 8 weeks' exposure to TCE. The concentration of formic acid in plasma at the end of the study was 1.05±0.61mM compared to control, 0.39±0.17mM. In the liver, formic acid was present at a concentration of 1mM in both control and treated mice while in the kidney it was higher at 2mM in both treated and controls. We also report that trichloroacetic acid (TCA) a metabolite of TCE also causes formic aciduria, at doses likely to arise in vivo after 1000mg/kg TCE namely 16 and 32mg/kg. Urinary formic acid peaked 24h after dosing at 4mg formic acid excreted/mouse. Thus, as in male and female rats (Yaqoob et al., 2013) male mice show a marked formic aciduria following TCE which after 8 weeks' exposure did not produce renal injury, but the small rise in renal biomarkers suggest renal damage may occur following longer exposure. Thus, TCE-induced formic aciduria may be a contributor factor in the chronic renal injury seen in male and female rats and mice.

Action Learning: a new method to increase tractor rollover protective structure (ROPS) adoption.

Action Learning is a problem-solving process that is used in various industries to address difficult problems. This project applied Action Learning to a leading problem in agricultural safety. Tractor overturns are the leading cause of fatal injury to farmworkers. This cause of injury is preventable using rollover protective structures (ROPS), protective equipment that functions as a roll bar structure to protect the operator in the event of an overturn. For agricultural tractors manufactured after 1976 and employee operated, Occupational Safety and Health Administration (OSHA) regulation requires employers to equip them with ROPS and seat belts. By the mid-1980s, US tractor manufacturers began adding ROPS on all farm tractors over 20 horsepower sold in the United States (http://www.nasdonline.org/document/113/d001656/rollover-protection-for-farm-tractor-operators.html). However, many older tractors remain in use without ROPS, putting tractor operators at continued risk for traumatic injury and fatality. For many older tractor models ROPS are available for retrofit, but for a variety of reasons, tractor owners have not chosen to retrofit those ROPS. The National Institute for Occupational Safety and Health (NIOSH) attempted various means to ameliorate this occupational safety risk, including the manufacture of a low-cost ROPS for self-assembly. Other approaches address barriers to adoption. An Action Learning approach to increasing adoption of ROPS was followed in Virginia and New York, with mixed results. Virginia took action to increase the manufacturing and adoption of ROPS, but New York saw problems that would be insurmountable. Increased focus on team composition might be needed to establish effective Action Learning teams to address this problem.

Real-time monitoring of superoxide generation and cytotoxicity in neuroblastoma mitochondria induced by 1-trichloromethyl-1,2,3,4-tetrahydro-beta-carboline.

The potential neurotoxin 1-trichloromethyl-1,2,3,4-tetrahydro-beta-carboline (TaClo) has recently been suggested to be a causative factor in the clinical development of parkinsonian symptoms after long-term exposure to precursor compounds such as the hypnotic chloral hydrate. TaClo is known to cause cell death in dopaminergic neuronal cells, however, the pathway and mechanisms remain undefined. This study reports for the first time that TaClo promotes cytotoxicity in SH-SY5Y neuroblastoma cells within 2 hours of initial exposure. TaClo also caused superoxide production from isolated mitochondria, which was comparable in response time and magnitude to production elicited by more established respiratory inhibitors such as rotenone and antimycin A. These findings present new evidence in support of TaClo-induced neuronal death via superoxide signalling and oxidative stress.

Aerial lift fall injuries: a surveillance and evaluation approach for targeting prevention activities.

PROBLEM: Work on aerial lift platforms exposes workers to fall hazards. The objective of this study was to identify the most common injury scenarios and determine current research gaps for addressing fall incidents associated with aerial lifts. METHODS: Three databases were searched: Census of Fatal Occupational Injuries (CFOI), NIOSH Fatality Assessment and Control Evaluation (FACE) reports, and OSHA Incident Investigation Records. RESULTS: The majority of falls/collapses/tipovers were within the height-category of 10-29 feet. Tipovers comprised 44-46% of boom-lift falls and 56-59% of scissor-lift falls. Constructing and repairing activities were most commonly associated with fall/collapse/tipover incidents. DISCUSSION: CFOI and OSHA/FACE show convergent data, suggesting similar scenarios for aerial lift tipovers. IMPACT ON INDUSTRY: The analysis provides the aerial lift industry information to prioritize their efforts on aerial lift design.

Transport refusal by hypoglycemic patients after on-scene intravenous dextrose.

OBJECTIVES: Administration of intravenous (IV) dextrose to hypoglycemic patients is delegated to advanced care paramedics in Ontario. Following a quality assurance review, which revealed that 47% of patients refused transport after receiving IV dextrose, the authors studied whether such patients seek additional medical care in the three days following the initial refusal. METHODS: Sequential ambulance call reports for on-scene treatments of hypoglycemia were examined, and a standardized telephone survey of the patients was conducted. Patient satisfaction was assessed using a five-point Likert scale. Data were collected from April 1999 to March 2000. RESULTS: One hundred patients were studied, with ages ranging from 20 to 92 years (mean 53.2 years). The average Glasgow Coma Scale (GCS) score on presentation was 8.7 +/- 3.5. The average blood glucose level before administration of IV dextrose was 1.91 +/- 0.63 mmol/L. Sixty-eight percent of the patients refused transport. Significant differences between the transported group and the refusal group were age (transported 64.7 years, refused 47.8 years, p = 0.002) and initial blood glucose (transported 1.8, refused 2.1, p = 0.001). No difference was found in terms of repeat access to health care for related complaints. Patient satisfaction was high in both groups, with no difference in the overall satisfaction with paramedics' care (4.76 +/- 0.58 vs 4.75 +/- 0.45). CONCLUSIONS: The practice of treating patients for symptomatic hypoglycemia and leaving them at the scene appears to be safe. Further study is required to confirm this.

The binding characteristics of transcortin, thyroxine binding globulin and pre-albumin in Jamaicans

The binding characteristics of Thyroxine Binding Globulin(TBG) Pre-albumin (TBPA) and Transcortin in Jamaicans were found to be similar to those described elsewhere. The previously reported diminution in adrenocortical and thyroidal function associated with normal plasma cortisol and thyroxine levels cannot therefore be ascribed to an increase in the plasma protein binding of these hormones (AU)

Thyroid function in euthyroid Jamaicans

Thyroid function has been investigated in 32 hospitalized euthyroid Jamaicans. The in vivo investigations performed were measurement of 2«, 4 and 24 hr thyroidal uptake of 131I, thyroidal and renal clearances of radioiodide, absolute iodide uptakes and, in 6 subjects, radiothyroxine turnover studies. Thyroxine binding globulin and prealbumin capacities were measured in a small number of cases. Results obtained in all these investigations agreed well with those found in temperate climates and are at variance with previous finding of low 24 hr thyroidal uptakes of 131I in euthyroid Jamaicans, associated with a normal serum protein-bound iodine.(AU)

Plasma insulin responses to oral glucose in normal and diabetic Jamaicans

The plasma insulin reponses to oral glucose have been determined in 96 normal and diabetic Jamaican subjects during standard oral glucose tolerance tests. The results are discussed with respect to: (a) possible aetiological factors causing diabetes in Jamaica and (b) the existence or not of racially determined differences in metabolic responses (AU)

Thyroxine turnover studies in Jamaicans

Radioactively labelled thyroxine (T4 - 125 I) has been used to carry out studies on thyroxine turnover in Jamaicans subjects. The decrease in plasma radioactivity following intravenous injection of labelled T4 has two components. The slow component lasting from 1 to 10 days post injection may be mathematically analysed to give the following data: (a) thyroxine distribution space; (b) total extra thyroidal thyroxine; (c) fractional turnover rate of the hormone and (d) thyroxine secretion rate. The results obtained in six normal Jamaican subjects agree well with those found by workers in North America and Europe. The fast component (10 minutes to 4 hours post injection) has been analysed in 8 normal, 2 hypothyroid and 1 thyrotoxic subjects using simultaneously injected albumen 125I and thyroxine 131I. This technique has previously been used by Oppenheimer et al (1967). It has until recently been thought that the cellular uptake of thyroxine was dependent on the concentration of diffusible (non protein bound) thyroxine in plasma. The results presented here show cellular uptake values 100 times greater than can be explained on this basis. These data have been analysed by a computer programme designed by Dr. J. B. Shepherd, Department of Physics, U.W.I. (AU)

Reassessment of thyroid function in euthyroid Jamaicans

In 1964 Goldberg et. a.l reported the results of a thyroid function study in a large group of normal Jamaicans. Very low 24 hour thyroidal uptakes of I131 were obtained, the mean being 13.8 percent of the dose. In view of these findings thyroid function was reassessed in 32 euthyroid Jamaican subjects. Investigations performed included, estimation of plasma inorganic iodide, 2, 4, and 24 hour thyroidal uptakes of radio iodide, absolute thyroidal iodide uptake and thyroidal and renal clearances of plasma iodide. Results obtained in all these investigations agreed well with those found in temperate climates and are at variance with the findings of Goldberg et al (AU)