Objective To investigate the functional activity and connectivity of the insular cortex at rest in persons with low back pain (LBP).Methods Twelve healthy subjects (male 6,female 6 ; age 24.8 ± 3.3 years) were given fMRI 3.0T scans at rest.Back muscle pain was then induced with an intramuscular injection of 3％ hypertonic saline solution and a second scan was performed.The pain-free and in-pain fMRI data were compared using paired t-tests to highlight any changes in the functional connectivity of the anterior and posterior insular cortex on both sides.Pain severity was quantified using a visual analogue scale (VAS).Results Ratings of LBP severity peaked at 6.02 ± 1.96 on the VAS.The functional connectivity of the inferior insular cortex with the frontal cortex,the thalamus and the parahippocampal gyrus was enhanced when the subjects were in pain,but connectivity with the posterior cingulate cortex,the precuneus,the temporal cortex,the paracentral lobule and the cerebellar tonsil was reduced.The inferior parietal lobule exhibited significantly enhanced connectivity with the anterior insular cortex,but reduced connectivity with the posterior insular cortex.In addition,the medial cingulate cortex displayed decreased functional connectivity with the anterior insular cortex,but increased functional connectivity with the posterior insular cortex when the subjects were in pain.Conclusion This study has revealed impeded functional connectivity of the insular cortex when experiencing LBP at rest.This may possibly be related to pain's disruption of cognition and emotion.

Objective: To investigate the possible role of IL17-and IL22-secreting cells combined with patch test for the prediction of formaldehyde-induced occupational allergic contact dermatitis(OACD). Methods: From October 2014 to October 2016, totally 131 formaldehyde-exposed workers(49 cases with inflammatory skin lesions,82 ones without inflammatory skin lesions)and 63 non-exposed health controls were recruited. Patch-test was performed in 49 cases of formaldehyde-exposed workers with inflammatory skin lesions. Circulating IL17+and IL22+Tcell subsets were assessed by flow cytometry(FCM). Results: Among 49 cases of formaldehyde-exposed workers with inflammatory skin lesions,32 cases were with positive patch-test while 17 cases with negative patch-test. The proportions of circulating CD3+CD8-IL17+ and CD3+CD8-IL22+ cells from patch-test(+) formaldehyde-exposed workers were significantly higher than that of patch-test(-)group, formaldehyde-exposed workers without skin lesions and non-exposed controls(P<0.05). The proportions of circulating CD3+CD8-IL17+ and CD3+CD8-IL22+cells from patch-test(-)group and formaldehyde-exposed workers without skin lesions were also higher than that of non-exposed controls(P<0.05). But there was no significant difference between patch-test(-)group and formaldehyde-exposed workers without skin lesions(P>0.05). Peripheral CD3+CD8+IL17+and CD3+CD8+IL22+cells were also detected in spite of small amounts. The percentages of CD3+CD8+IL17+and CD3+CD8+IL22+ cells inperipheral blood from patch-test(+)formaldehyde-exposed workers were enhanced significantly, compared to patch-test(-)group, formaldehyde-exposed workers without skin lesions and non-exposed controls(P<0.05). The proportions of circulating CD3+CD8+IL17+ and CD3+CD8+IL22+ cells from patch-test(-)group and formaldehyde-exposed workers without skin lesions were significantly higher than that of non-exposed controls(P<0.05). But there was no significant difference between patch-test(-) group and formaldehyde-exposed workers without skin lesions(P>0.05). Conclusion The proportions of circulating IL17+ and IL22+T cells(both CD8-and CD8+)are enhanced in formaldehyde-exposed workers at proposed OEL, possibly involved in the development of formaldehyde-induced OACD.The detection of IL17-and IL22-secreting cells combined with formaldehyde patch test help to screen the workers with allergy property and prevent OACD.