As a participating laboratory for the OECD Hershberger validation program, we conducted a phase 3 trial to test the reliability of the Hershberger assay using coded substances. Male Sprague-Dawley rats were castrated at 6 weeks of age and allowed to recover for 8 days. All the coded substances were administered orally once daily for 10 consecutive days. In the antagonist version of the assay, 0.4 mg kg(-1) of testosterone propionate (TP), a reference androgen, was co-administered with the coded compounds C, D, H, I or K, by a subcutaneous injection. As anticipated, TP alone produced statistically significant increases in the five mandatory accessory sex organ weights. The coded substance L (trenbolone 40 mg kg(-1)), the test agonist, caused significant increases in the weights of the androgen-dependent tissues. The five coded compounds, p,p'-DDE at two doses (codes C and I), linuron at two doses (codes D and K) and flutamide (code H), all significantly decreased the weights of the TP-stimulated sex organs. These results suggest the OECD Hershberger assay to be a reliable screening method for detecting androgen agonists and antagonists.
[Purpose] The purpose of this study was to determine the effect of the cocontraction of
masticatory muscles during neck stabilization exercises on changes in the thickness of the
neck flexors. [Subjects and Methods] Twenty subjects performed neck stabilization only
exercise and neck stabilization exercise with simultaneous contraction of the masticatory
muscles. Changes in the thickness of the longus colli and sternocleidomastoid were then
measured by ultrasound. [Results] The thickness of the longus colli increased
significantly fallowing cocontraction of the masticatory muscles and neck stabilization
exercise, whereas the exercise method used had no significant effect on the thickness of
the sternocleidomastoid. [Conclusion] Cocontraction of the masticatory muscles during neck
stabilization exercise is helpful in increasing the thickness of longus colli muscle.
[Purpose] The purpose of this study was to identify changes in the thicknesses of the
cervical flexors according to eye coordination during deep cervical flexor training.
[Subjects and Methods] Twenty normal adults were randomly selected, and during their deep
cervical flexor training and eye tracking, the thicknesses of the longus colli and the
sternocleidomastoid were measured using ultrasonic waves. [Results] The thickness of the
longus colli statistically significantly increased when deep cervical flexor training and
eye coordination were performed simultaneously. However, the thickness of the
sternocleidomastoid did not show statistically significant differences according to eye
coordination. [Conclusion] Eye coordination during deep cervical flexor training is likely
to increase the thickness of the longus colli selectively.
| Abstract | PURPOSE:The purpose of this study was to investigate the difference of trunk muscles activity during abdominal hollowing and bracing contraction in various position.
METHODS:This pilot test was carried out in a volunteer sample of normal adults(n=24) without a history of low back pain or injury. 24 subjects were randomly allocated to three groups(n=8) as a contraction method respectively. In hooklying position, trunk muscles activity of subjects was measured using EMG in various bridging position.
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