Two posture analysis approaches and their application in a modified rapid upper limb assessment evaluation

This paper presents two posture risk quantification methods: first, an event-based method where the most common and the worst postures are estimated in a task; second, a time-based method where posture distributions are calculated from random samples of observed postures in the task. A 'click-on-screen' posture data entry method was developed for the time-based posture analysis method to make the observation process easier and to reduce possible posture categorization bias. Both methods were used to quantify various work posture parameters among a study cohort of 733 subjects from a prospective epidemiological study of upper extremity musculoskeletal disorders. Composite posture indices using a modified Rapid Upper Limb Assessment (RULA) method were also computed using data obtained by the two posture analysis methods. Results showed that both methods were able to distinguish jobs with large differences in certain posture measures. However, they did not produce the same results and could not be used interchangeably. Risk evaluation criteria should be developed, either for specific posture parameters or as a composite index, with a well-defined postural analysis method, so that users can follow exact procedures and obtain comparable results. The event-based method is easy to use and may suit practitioners better, while the time-based method adds more information to the measurement and may suit users who want more detailed information about posture exposure.

Impaired cutaneous wound healing in granulocyte/macrophage colony-stimulating factor knockout mice

BACKGROUND

Wound healing involves various cells and cytokines, resulting in the regular progression of remodelling events. Granulocyte/macrophage colony-stimulating factor (GM-CSF) is a multifunctional pleiotropic cytokine and is known to facilitate wound healing, although the precise molecular and cellular mechanisms remain to be explored.

OBJECTIVES

To use GM-CSF gene knockout (GM-CSF KO) mice to investigate the role of GM-CSF in cutaneous wound healing following full-thickness skin injury.

METHODS

Full-thickness skin wounds were made in GM-CSF KO and wild-type mice. The wound closure, leucocyte infiltration, vascularization and extent of cytokine production were determined.

RESULTS

Wound healing was significantly delayed in GM-CSF KO mice, accompanied by reduced cytokine production (interleukin-6, monocyte chemoattractant protein-1 and macrophage inflammatory protein-2), and platelet-endothelial cell adhesion molecule-1 expression. Consequently there was reduced recruitment of neutrophils and macrophages and reduced vascularization in the wounds of GM-CSF KO mice. Although collagen deposition was delayed, it was significantly increased in the wounds of the GM-CSF KO mice in the later stages of wound healing.

CONCLUSIONS

We conclude that GM-CSF plays an important role in the complex network of effector molecules that regulate keratinocyte proliferation and the inflammatory response. These data have important implications for further development of the therapeutic manipulation of wound healing using GM-CSF.

Vasoactive intestinal polypeptide enhances oral tolerance by regulating both cellular and humoral immune responses

Vasoactive intestinal polypeptide (VIP) is an important signal molecule of the neuroendocrine-immune network. In the immune system, VIP has been found to act as an endogenous anti-inflammatory mediator. In the current study, it was found that VIP administration regulated oral tolerance by inhibiting both cellular and humoral responses. Compared with vehicle-treated mice, mice treated with VIP during the development of ovalbumin (OVA)-induced oral tolerance exhibited the least delayed-type hypersensitivity (DTH), showed profoundly reduced proliferative capacity and produced less interferon (IFN)-gamma, interleukin (IL)-6, IL-5, IL-10 and interferon-inducible protein (IP-10). IgA-secreting cells in the gut as well as OVA-specific IgG and other isotypes levels in plasma were inhibited significantly after VIP-treatment. The VPAC2 receptor may be involved in VIP-mediated oral tolerance enhancement. Taken together, these results suggest that VIP enhanced oral tolerance via regulating both cellular and humoral responses.

Effects of follicular atresia and size on the developmental competence of bovine oocytes: A study using the well-in-drop culture system

The effect of granulosa cell (GC) apoptosis and follicle size on the competence of bovine oocytes were studied using a well-in-drop (WID) oocyte/embryo culture system, which allows identification of follicular origin. Hatching rates of blastocysts did not differ (P>0.05) between oocytes cultured in the WID system (13%) and those cultured in the conventional group system (16%). Hatching rates of blastocysts were higher (P<0.05) in early atretic (17%) than in non-atretic (8%) and late atretic follicles (10%) of the same size (4-8mm), and in 6-8mm (22%) than in 4-5mm follicles (15%) at the early atretic stage. More oocytes (P<0.05) from late atretic (17%) than from non-atreteic (7%) or early atretic follicles (9%) of the same size (4-8mm) were arrested at Grade 1 cumulus expansion (only cells in the peripheral two layers began to expand). Similarly, more oocytes from 2 to 3mm follicles (30%) than from 6 to 8mm follicles (21%) at the same (late) atretic stage had Grade 1 cumulus expansion (P<0.05). Hatching blastocyst percentages of oocytes with Grade 3 (all layers of the cumulus except corona radiate cells expanded) or Grade 4 (full) cumulus expansion were higher in early atretic (20%) than in non-atretic (13%) or late atretic follicles (12%). Hatching blastocyst percentages of oocytes from follicles at the early atretic stage increased as cumulus expanded from Grade 2 (9%) to Grade 4 (27%). Regardless of the degree of follicle atresia, 72-76% of the floating cells in the follicular fluid (FF) were undergoing apoptosis. The floating cell density in FF was highly (r=0.6-0.7) correlated with oocyte developmental potency. In conclusion, the WID culture system was as efficient as group culture and allowed identification of follicular origin. Furthermore, the developmental potential of oocytes was affected by GC apoptosis, follicle size and cumulus expansion, and the floating cell density in FF could be used as a simple and non-invasive marker of oocyte quality.

Targeting SPARC expression decreases glioma cellular survival and invasion associated with reduced activities of FAK and ILK kinases

Secreted protein acidic and rich in cysteine (SPARC) is an extracellular glycoprotein expressed in several solid cancers, including malignant gliomas, upon adoption of metastatic or invasive behaviors. SPARC expression in glioma cells promotes invasion and survival under stress, the latter process dependent on SPARC activation of AKT. Here we demonstrate that downregulation of SPARC expression with short interfering RNA (siRNA) in glioma cells decreased tumor cell survival and invasion. SPARC siRNA reduced the activating phosphorylation of AKT and two cytoplasmic kinases, focal adhesion kinase (FAK) and integrin-linked kinase (ILK). We determined the contributions of FAK and ILK to SPARC effects using SPARC protein and cell lines engineered to overexpress SPARC. SPARC activated FAK and ILK in glioma cells previously characterized as responsive to SPARC. Downregulation of either FAK or ILK expression inhibited SPARC-mediated AKT phosphorylation, and targeting both FAK and ILK attenuated AKT activation more potently than targeting either FAK or ILK alone. Decreased SPARC-mediated AKT activation correlated with a reduction in SPARC-dependent invasion and survival upon the downregulation of FAK and/or ILK expression. These data further demonstrate the role of SPARC in glioma tumor progression through the activation of intracellular kinases that may provide novel therapeutic targets for advanced cancers.

Modeling the spontaneous activity of the auditory cortex

We present a rate model of the spontaneous activity in the auditory cortex, based on synaptic depression. A Stochastic integro-differential system of equations is derived and the analysis reveals two main regimes. The first regime corresponds to a normal activity. The second regime corresponds to epileptic spiking. A detailed analysis of each regime is presented and we prove in particular that synaptic depression stabilizes the global cortical dynamics. The transition between the two regimes is induced by a change in synaptic connectivity: when the overall connectivity is strong enough, an epileptic activity is spontaneously generated. Numerical simulations confirm the predictions of the theoretical analysis. In particular, our results explain the transition from normal to epileptic regime which can be induced in rats auditory cortex, following a specific pairing protocol. A change in the cortical maps reorganizes the synaptic connectivity and this transition between regimes is accounted for by our model. We have used data from recording experiments to fit synaptic weight distributions. Simulations with the fitted distributions are qualitatively similar to the real EEG recorded in vivo during the experiments. We conclude that changes in the synaptic weight function in our model, which affects excitatory synapses organization and reproduces the changes in cortical map connectivity can be understood as the main mechanism to explain the transitions of the EEG from the normal to the epileptic regime in the auditory cortex.

Quantifying repetitive hand activity for epidemiological research on musculoskeletal disorders--part I: individual exposure assessment

An exposure measurement approach is described for quantifying repetitive hand activity of individual workers in a prospective epidemiological study on work-related upper extremity musculoskeletal disorders. A total of 733 subjects were involved in this study at the baseline. Hand activities were quantified by force and repetition. Force levels were measured by workers' self-reports, ergonomists' estimates based on observation and measurements with instrumentation. Repetition levels were measured by detailed time-motion analyses using two repetitive hand activity definitions and ergonomists' estimates using scales for the American Conference of Governmental Industrial Hygienists hand activity level and the Strain Index. Results showed that the present exposure assessment approach seems to be able to quantify force level and repetitiveness of hand activities. Repetitive hand activity is quantified differently depending on whether forceful hand exertion or repetitive muscle activity is used as the definition. These hand activity definitions may quantify different physical exposure phenomena. Individual exposure assessment is important in epidemiological research of musculoskeletal disorders as there are interactions between the individual subjects and the measured parameters. These interactions may vary between exposure parameters.

Quantifying repetitive hand activity for epidemiological research on musculoskeletal disorders--part II: comparison of different methods of measuring force level and repetitiveness

This paper focuses on comparisons between the different methods of assessing repetitive hand activities. Various methods were used to measure hand force and repetitiveness of hand activities on 733 subjects in the study described by Bao et al. (2006). Two definitions of repetitiveness were used in analysis of detailed time studies of repetitive hand activities and four parameters of the American Conference of Governmental Industrial Hygienists (ACGIH) hand activity level (HAL) and the Strain Index methods were estimated by ergonomists and used to quantify repetitiveness. Hand forces were measured or estimated using three different methods: 1) measured with a force gauge or mimicked on a force gauge (force matching); 2) estimated by ergonomists using rating scales; 3) self-reports by subjects. The jobs were also evaluated using the ACGIH HAL and Strain Index methods when different repetitiveness quantification methods were used. Results showed that different definitions of repetitive exertion might lead to measuring different physical exposure phenomena and produce very different results. There were poor correlations between the measures of repetitiveness estimated by the different methods. Correlations between force quantifications using different methods were also poor. This suggests that parameters measured by different methods might not be interchangeable. Both the ACGIH HAL and Strain Index methods identified more 'hazardous' jobs when repetitiveness was estimated by ergonomists than when it was calculated by detailed time studies of forceful hand exertions. The Strain Index method identified more 'hazardous' jobs than the ACGIH HAL method. Overall, the between-methods agreements were found to be moderate to substantial.

Compensation in pre-synaptic dopaminergic function following nigrostriatal damage in primates

Clinical symptoms of Parkinson's disease only become evident after 70-80% reductions in striatal dopamine. To investigate the importance of pre-synaptic dopaminergic mechanisms in this compensation, we determined the effect of nigrostriatal damage on dopaminergic markers and function in primates. MPTP treatment resulted in a graded dopamine loss with moderate to severe declines in ventromedial striatum (approximately 60-95%) and the greatest reductions (approximately 95-99%) in dorsolateral striatum. A somewhat less severe pattern of loss was observed for striatal nicotinic receptor, tyrosine hydroxylase and vesicular monoamine transporter expression. Declines in striatal dopamine uptake and transporter sites were also less severe than the reduction in dopamine levels, with enhanced dopamine turnover in the dorsolateral striatum after lesioning. The greatest degree of adaptation occurred for nicotine-evoked [(3)H]dopamine release from striatal synaptosomes, which was relatively intact in ventromedial striatum after lesioning, despite > 50% declines in dopamine. This maintenance of evoked release was not due to compensatory alterations in nicotinic receptor characteristics. Rather, there appeared to be a generalized preservation of release processes in ventromedial striatum, with K(+)-evoked release also near control levels after lesioning. These combined compensatory mechanisms help explain the finding that Parkinson's disease symptomatology develops only with major losses of striatal dopamine.

Evaluation of clinical and serological data from Taenia solium cysticercosis patients in eastern Inner Mongolia Autonomous Region, China

Neurocysticercosis (NCC) is one of the major causes of neurological disease in China. ELISA and immunoblotting using glycoproteins purified by preparative isoelectric focusing were used to detect human cysticercosis in Tongliao area, Inner Mongolia, China in 1998. Approximately 89% (39 of 44 inpatients and outpatients with suspected NCC at Tongliao City Hospital) were residents of Inner Mongolia. About 53% were male and 77% were of working age (18-59 years), and 32% were farmers. Immunoblotting and ELISA showed a high correlation. Of the 44 patients, 31 positive by cerebral computed tomography (CT) scan were confirmed serologically to have cysticercosis. In the ELISA, patients with no lesions by CT scan had lower OD values, similar to those of normal serum. These findings confirm that both ELISA and immunoblotting assays are sufficiently sensitive to detect asymptomatic or symptomatic cysticercosis patients.

Microsatellites in starch-synthesizing genes in relation to starch physicochemical properties in waxy rice ( Oryza sativa L.)

Rice starch is composed of amylose and amylopectin. Amylose content, an important determinant of rice starch quality, is primarily controlled by the waxy gene, encoding granule-bound starch synthase (GBSS). The starch branching enzyme (SBE) and soluble starch synthase (SSS) play major roles in the synthesis of amylopectin. Microsatellite polymorphisms in the three genes, the wx gene encoding granule-bound starch synthase I, the SBE gene encoding starch branching enzyme I and the SSS gene encoding soluble starch synthase I, were studied for 56 accessions of waxy rice ( Oryza sativa L.). Four (CT)(n) microsatellite alleles, (CT)(16), (CT)(17), (CT)(18) and (CT)(19), at the wx locus were detected in this set of waxy rice, of which (CT)(17) was the most frequent. Three (CT)(n) microsatellite allele classes were found at the SBE locus, (CT)(8) or (CT)(10) together with an insertion sequence of CTCTCGGGCGA, and (CT)(8) alone without the insertion. There were multiple microsatellites clustered at the SSS locus. However, these alleles can also be grouped into three classes, i.e. the allele class SSS-A = (AC)(2) em leader TCC(TC)(11) em leader (TC)(5)C(ACC)(11), the allele class SSS-B = (AC)(3) em leader TCT(TC)(6) em leader (TC)(4)C(ACC)(9), and the allele class SSS-C = (AC)(3) em leader TCT(TC)(6) em leader (TC)(4)C(ACC)(8). The analyses of starch physicochemical properties among different microsatellite genotypes indicated that the waxy rice group with the (CT)(19) allele, the SBE-A allele and the SSS-B allele was quite different from other groups. Nine out of 15 accessions with a high gelatinization temperature (GT) belonged to the wx (CT)(19) group, all of them belonged to the SBE-A group and 13 of them belonged to the SSS-B group. These microsatellites might be useful in marker-assisted breeding for the improvement of rice grain quality.

Induction and repair of HZE induced cytogenetic damage

Wistar rats were exposed to high-mass, high energy (HZE) 56Fe particles (1000 GeV/AMU) using the Alternating Gradient Synchrotron (AGS). The animals were sacrificed at 1-5 hours or after a 30-day recovery period. The frequency of micronuclei in the tracheal and the deep lung epithelial cells were evaluated. The relative effectiveness of 56Fe, for the induction of initial chromosome damage in the form of micronuclei, was compared to damage produced in the same biological system exposed to other types of high and low-LET radiation. It was demonstrated that for animals sacrificed at short times after exposure, the tracheal and lung epithelial cells, the 56Fe particles were 3.3 and 1.3 times as effective as 60Co in production of micronuclei, respectively. The effectiveness was also compared to that for exposure to inhaled radon. With this comparison, the 56Fe exposure of the tracheal epithelial cells and the lung epithelial cells were only 0.18 and 0.20 times as effective as radon in the production of the initial cytogenetic damage. It was suggested that the low relative effectiveness was related to potential for 'wasted energy' from the core of the 56Fe particles. When the animals were sacrificed after 30 days, the slopes of the dose-response relationships, which reflect the remaining level of damage, decreased by a factor of 10 for both the tracheal and lung epithelial cells. In both cases, the slope of the dose-response lines were no longer significantly different from zero, and the r2 values were very high. Lung epithelial cells, isolated from the animals sacrificed hours after exposure, were maintained in culture, and the micronuclei frequency evaluated after 4 and 6 subcultures. These cells were harvested at 24 and 36 days after the exposure. There was no dose-response detected in these cultures and no signs of genomic instability at either sample time.

A practical method for ergonomic and usability evaluation of hand tools: a comparison of three random orbital sander configurations

Tool and equipment purchasing decisions are constantly made by companies and workers, often with little objective information beyond word of mouth and marketing information. This study presents a pilot investigation of random orbital sanders using ergonomic and usability assessment techniques which can easily be applied in any industry. Three subjects performed a sanding task using three different tool configurations: 1) the current model sander, 2) current model with hose-swivel attachment, and 3) the new "ergonomically designed" model. Physical measurements were taken of muscle activity and wrist motion to complement think-aloud testing and a usability questionnaire. No significant differences were found in physical measurements between the three configurations. Participants strongly preferred the current model over the new model, reporting less perceived discomfort and vibration, despite what appeared to be improvements in the new design. Workplace changes intended to reduce the risk of injury sometimes may have no effect after significant capital investment, or in some cases even increase the risk of injury. Practical assessment of new tools or modifications can quickly determine whether the outcome is indeed an improvement. The results of this tool assessment highlight the need for objective information in tool and equipment design decisions.

Persistent and specific influences of early acoustic environments on primary auditory cortex

This study demonstrates that the adult form of 'tonotopic maps' of sound frequency in the rat primary auditory cortex (A1) arises from parallel developmental processes involving two cortical zones: the progressive differentiation and refinement of selectively tone-responsive receptive fields within an initially broadly-tuned posterior zone, and the progressive loss of tone-evoked, short-latency response over an initially large, very broadly tuned anterior zone. The formation of tonotopic maps in A1 was specifically influenced by a rat pup's early acoustic environments. Exposure to pulsed tones resulted in accelerated emergence and an expansion of A1 representations of those specific tone frequencies, as well as a deteriorated tonotopicity and broader-than-normal receptive fields. Thus, auditory experiences during early postnatal development are important in shaping the functional development of auditory cortical representations of specific acoustic environments.