The internationally accepted limit values and the health effects of hand-transmitted vibration exposure have been described extensively in the literature from temperate climate countries but not from a tropical climate environment. Objectives: We conducted a systematic review of the health effects of hand-transmitted vibration exposure in tropical countries to determine the characteristics of hand-arm vibration syndrome in a warm environment and compared the findings with the results of the systematic reviews published by the US NIOSH. Methods: We searched major medical databases including MEDLINE, PubMed, Embase, CINAHL, Ovid and Cochrane based on the terms “hand arm vibration syndrome,” “hand transmitted vibration,” “vibration white finger” and “Raynaud” up to January 2011. Only studies conducted in a tropical or subtropical environment were selected for the review. The quality of the selected papers was assessed independently by two investigators using predefined criteria. A standard set of information was abstracted from the papers for review. Results: Only six papers from tropical countries and three papers from subtropical countries were available in the literature. No vibration white finger was reported in the tropical countries. Neurological symptoms were prevalent in the vibration-exposed workers. Finger coldness seems to be an important surrogate for vascular disorder in a tropical environment. Meta-analysis could not be performed due to inadequacy of the information reported in these papers. Conclusions: The current dose-response relationship in ISO5349-1 for hand-transmitted vibration exposure is not applicable to a tropical environment. Further studies on hand-arm vibration syndromes in tropical countries are needed.
Background: Carbon nanotubes (CNTs) have many potential applications, including as delivery systems for a variety of diagnostic or therapeutic agents. However, it has been suggested that exposure to carbon nano-materials may be a risk for the development of vascular diseases due to its impact on the vascular endothelium. Materials and Methods: Male Sprague-Dawley rats (180–200 g) were used to generate an atherosclerosis (AS) model, and the effect of intravenous administration of multi-walled carbon nanotubes (MWCNTs) on AS was studied. To further understand the underlying mechanisms, the effects of exposure of human umbilical vascular endothelial cells (HUVECs) to MWCNTs were examined. Results: Exposure to 200 μg/kg MWCNTs aggravated AS in this model. In addition, exposure to 50, 100 and 200 μg/kg MWCNTs increased the calcification of the aorta in the model. Short-term exposure also revealed that 200 μg/kg MWCNTs injured the endothelium in the aorta. MWCNTs disrupted the endothelial tight junction and induced endothelial cell death. Conclusion: The results demonstrated that MWCNTs could induce structural and functional changes in the endothelium, probably through vascular endotheliocyte injury, which eventually affected the development of AS in SD rats.
Objectives: Among the many chemicals used in a hair salon, exposure to thioglycolic acid (TGA) used for permanent waving solutions (PWS) potentially causes adverse health effects. However, no report has been previously published on the indoor air concentrations of TGA in a beauty salon that contributes to assessment of exposure to TGA of hairdressers and their customers. This study aimed to demonstrate the present concentration levels of TGA in indoor air of a beauty salon where the PWS containing ammonium thioglycolate was actually used for perm treatments. Methods: A field measurement of TGA, dithiodiglycolic acid (DTDGA, a reaction product of TGA and cysteine residues of hair keratin) and ammonia was carried out in a beauty salon located at Tokyo, Japan, from June 30 to July 2. Both TGA and DTDGA were collected in water using an impinger and determined by high performance liquid chromatography (HPLC). Results: The indoor air concentrations of TGA were below the limit of detection of 0.008 mg m−3 at every event and much lower than occupational safety guideline levels set by the NIOSH and ACGIH. Meanwhile, the concentrations of ammonia ranged from 0.15 to 0.87 mg m−3, and relatively higher concentrations were found during perm events and in samples collected near stations used for perm treatments. Concentrations of DTDGA varied from <0.026 mg m−3 to 0.75 mg m−3. Conclusions: There was a different emission process of TGA and ammonia from PWS, and airborne TGA is not important as a possible exposure route for hairdressers and customers in this beauty salon.
Background and Objectives: Exposure to n-hexane, a neurotoxic solvent, has been associated with sensorimotor polyneuropathy, both in occupationally exposed workers and in glue-sniffing addicts. The present study was carried out to ascertain whether exposure to sub-TLV levels of n-hexane was associated with electrophysiological abnormalities and to determine if these possible abnormalities have any correlations with parameters such as the biological exposure index (BEI) of this neurotoxic chemical, workers’ TWA exposure to n-hexane and/or duration of employment. Materials and Methods: Twenty-seven asymptomatic male workers from 6 shoemaking workshops were studied and compared with a group of 20 age- and sex-matched normal controls with no history of exposure to any neurotoxic agent. They underwent physical examinations as well as conventional needle electromyographic examinations and sensory and motor nerve conduction studies of upper and lower extremities. The TWA exposure to n-hexane and urinary concentration of free 2,5-hexanedione were also determined. Data were analyzed using version 16.0 of the SPSS/PC statistical package. Results: The TWA exposure to n-hexane was estimated to be 83.2 mg/m3. Electrophysiological studies showed that the amplitudes of sensory nerve action potential (SAP) for median and sural nerves were significantly lower in exposed subjects than in unexposed normal controls. Additionally, a significant correlation was found between these decreases and the urinary concentration of free 2,5-hexanedione. Conclusion: The significant decrements in SAP amplitudes for the median and sural nerves may be considered as appropriate indicators for early detection of n-hexane-induced peripheral neuropathy in asymptomatic workers with current exposure to sub-TLV levels of n-hexane.
Objective: To test the validity of a sitting pad (SP) to measure desk based sitting time and transitions, against camera derived direct observation; and to compare the data with those from inclinometers in the ActivPAL3 (AP) and ActiGraph GT3X+ (AG). Methods: Australian employees (n=13; 9 women; mean age 30 ± 6.5 years) were provided with a SP, AG and AP in 2011. A camera recorded chair based transitions during a prescribed and a free living protocol. Mean sitting time and transitions were calculated for each device and intra-class correlations (ICCs) and mean differences between (a) the SP and the camera and (b) the AP, AG and camera, were compared. Results: During the prescribed protocol, the smallest mean differences compared with the camera were for the SP; sitting time 0.30 ± 0.21 minutes, transitions −0.46 ± 0.78. During free living, both the SP and AP (set to record events greater than 3 seconds) showed excellent levels of agreement with the camera for sitting time (0.999 and 0.990 respectively) and transitions (0.997 and 0.928 respectively). Agreement between the camera and the AG was poor for both sitting time and transitions (0.257 and 0.033 respectively). Conclusions: The SP is a highly accurate measure of desk based sitting time and transitions and provides novel measurement and intervention opportunities for research into occupational sitting.