Human Body Loading Research Articles

Persistent, bioaccumulative and toxic substances in fish: Human health considerations

Fish are important dietary items that provide essential nutrients. Fish however, bioaccumulate monomethyl mercury (MMHg) and organo-halogenated pollutants (OHP) that are persistent bioaccumulative and toxic substances (PBTS). Unlike man-made OHP, MMHg is mainly of natural origin but background concentrations of aquatic systems are determined by the environmental Hg-methylating potential. Industrial activities can modulate environmental discharges and fish bioaccumulation of PBTS. Fish and seafood consumption are associated with human body load of PBTS, but farming practices that utilize fishmeal increase the terrestrial food chain resulting in farm-animal accumulation of PBTS. These substances are neurotoxic and endocrine active that can impact humans and wild life, but chemical characteristics of MMHg and OHP modulate interactions with animal tissues. MMHg is protein reactive with a faster metabolism (months) than OHP that are stored and slowly (years) metabolized in fat tissues. Except for brain-Hg, neither Hg nor OHP in tissues are markers of toxic effects; however, deficits in neurobehavioral test-scores of children have been shown in some fish-eating populations. These deficits are transient and within normal range, and are not prodromes of neurological diseases. Although population studies show that consumption of fish at current levels of contamination do not explain neurological disorders, endocrine activity remains controversial. Understanding risk of hazard caused by fish-PBTS consumption requires a wide range of expertise. We discuss chemical, toxic, metabolic, and ecological characteristics associated with PBTS in fish. There are proven health outcome derived from fish consumption, while risk of exposure to avoidable PBTS is a chance that can be minimized by societal actions.

Plantar pressure changes in normal and pathological foot during bipedal standing

Background : Plantar pressure measurement during bipedal standing provides an important information of loading of human body on foot under various postural activities. Therefore, the objective of the present work was to monitor the plantar pressure during bipedal standing in normal and pathological conditions. Use of orthotics in attenuating the peak pressure to distribute it uniformly on plantar surface of the foot was also examined. Methods: The pedobarographs of 66 subjects were recorded using computer assisted indigenously developed optical pedobarograph. The pedobarographs were evaluated using Asha 3-D software developed during present study. Standard size universal orthotics (FootmaxxTM, Canada) was used to determine the effect in attenuating the peak pressure. Results: Results showed distribution of plantar pressure in the right and left foot of normal subject under the various regions was not equal. It was observed that among the normal subjects 17% experienced equal pressure on the both feet, 7% showed greater pressure on left foot and 76% found higher load on the right foot. Similarly the pathological subjects were analyzed and noticed the changes in the pedobarographs depending upon the type and location of pathology. It was found that orthotics improved the plantar pressure and distributed it uniformly to make the person standing comfortably. Conclusion: Plantar pressure measurement techniques are useful in the analysis and understanding of the biomechanics of human foot. It was found that orthotics attenuated the peak pressure and distributed it uniformly on the plantar area of the foot. The data seem to be useful in understanding the biomechanics of bipedal standing.