[Chromosome aberration and micronucleus frequency in peripheral blood lymphocytes in radiation workers].

OBJECTIVE: To investigate chromosome aberration and micronucleus frequency in peripheral blood lymphocytes in workers engaged in radiation for a long time, to reduce occupational hazard caused by ionizing radiation, and to further strengthen health surveillance. METHODS: A total of 366 members of medical staff engaged in radiation work who underwent physical examinations in Hangzhou Hospital of Prevention and Treatment of Occupation Diseases from 2014 to 2015 were enrolled as radiation group, consisting of staff engaged in X-ray diagnosis, diagnostic radiology, radiotherapy, and interventional radiology. Another 100 members of medical staff without exposure to radiation were enrolled as control group. Whole blood culture was used to measure chromosome aberration and micronucleus frequency in peripheral blood lymphocytes. RESULTS: The radiation group had a significantly higher rate of chromosome aberration than the control group (0.30% vs 0.09% , χ(2)= 13.43, P<0.01), as well as a significantly higher micronucleus frequency than the control group (2.09‰ vs 0.08‰, χ(2)=74.4, P<0.01). The abnormal rates of chromosome aberration and micronucleus showed no significant differences across radiation workers with different working years (P>0.05). The staff engaged in X-ray diagnosis, diagnostic radiology, radiotherapy, and interventional radiology had rates of chromosome aberration of 0.25%, 0.25%, 0.23%, and 0.41%, respectively, which showed a significant difference between the staff at these four posts (χ(2)=8.22, P<0.05); the micronucleus frequencies in the staff at these four posts were 1.36‰, 1.28‰, 1.14‰, and 3.79‰, respectively, and showed a significant difference between the staff at these four posts (χ(2)=251.09, P<0.01). CONCLUSION: Radiation workers are exposed to lowdose ionizing radiation for a long time, which may cause significant increases in the rate of chromosome aberration and micronucleus frequency in peripheral blood lymphocytes.

Improvement of the survival and therapeutic effects of implanted mesenchymal stem cells in a rat model of coronary microembolization by rosuvastatin treatment.

OBJECTIVE: As the impairment of myocardial micro-environments with local inflammatory reactions due to coronary micro-embolization (CME) reduces the survival of transplanted stem cells (SCs). We hypothesized that rosuvastatin treatment could improve the SC survival and enhance their therapeutic effects. MATERIALS AND METHODS: Rat bone marrow-derived mesenchymal stem cells (BMSCs) were infected with lentivirus carrying the green fluorescent protein (GFP) gene. To develop a CME model, rats were injected with a suspension of microthrombotic particles (MTPs) into the left ventricle to obstruct the ascending aorta. GFP-BMSCs were injected with MTPs simultaneously. Rosuvastatin treatment was started 7 days before BMSC transplantation and ended 7 days after transplantation. RESULTS: Expressions of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were examined by the molecular methods. GFP-positive BMSCs were detected by fluorescence staining. Neovascularization was determined by immunohistochemistry. Myocardial morphology was identified by H&E and Masson's trichrome staining. Cardiac function was quantified by echocardiography. Three days after CME, the multifocal myocardial necrosis with extensive infiltration of inflammatory cells was observed, accompanied by high expression of TNF-α and IL-1ß. Rosuvastatin treatment reduced the infiltration of inflammatory cells and TNF-α and IL-1ß expression. 28 days after transplantation, BMSC therapy with rosuvastatin promoted the survival of implanted cells by ≈45-fold while compared with BMSC therapy alone. BMSC therapy with rosuvastatin (instead of BMSC therapy alone) upregulated the VEGF and bFGF expression, increased the capillary density and improved the cardiac function. CONCLUSIONS: These data suggested that rosuvastatin treatment promoted the survival of transplanted SCs and enhanced their therapeutic effects for CME.

[Ideal current of injury and R-wave sensingvalues for identifying optimized placement of right ventricular active-fixation pacing leads].

OBJECTIVE: To define the ideal COI and R-wave sensing values for optimized placement of right ventricular active-fixation pacing leads. METHODS: Three hundred and six patients underwent right ventricular active-fixation lead implantation in our department from January 2013 to December 2014 were enrolled in this prospective pilot cohort study. According to the times needed for successful implantation, patients were divided into group SP (success poisoning after single procedure, n=229) and group MP (success poisoning after multiple procedures, n=77). Current of injury (COI) was characterized as the magnitude of ST-segment elevation. Pacing parameters were measured up to 10 minutes after lead fixation. RESULTS: (1) COI at 1 minute (COI1, (9.34±2.44)mV vs. (3.19±1.36)mV, P<0.001) and 10 minutes (COI10, (4.99±2.04)mV vs. (1.91±0.62)mV, P<0.001) after lead fixation was significantly higher in SP group compared to MP group. R-wave sensing measured at 10 minutes after lead fixation (R10 min) was also significantly higher in SP group than in MP group ((14.2±4.5)mV vs. (5.4±0.7)mV, P<0.001). Pacing threshold measured at 10 minutes after lead fixation was significantly lower ((0.65±0.18)V vs. (1.90±0.40)V, P<0.001) in SP group than in MP group. (2) The optimized placement of pacing lead was related with COI1(OR=0.247, 95%CI 0.098-0.623, P=0.003) and R10 min(OR=0.081, 95%CI 0.015-0.428, P=0.003). (3) The cut-off value of COI1 was 4.77 mV(sensibility 0.97, specificity 0.95), the cut-off value of R10 min was 7.25 mV (sensibility 0.96, specificity 1.00) for optimized lead fixation. After 3 months follow up, pacing threshold was (0.68±0.19)V, R-wave sensing was (12.1±3.6)mV, and pacing impedance was (543±107)Ω for right ventricular active-fixation pacing leads. CONCLUSIONS: COI1>4.77 mV and R10 min>7.25 mV are the ideal parameters for identifying optimized placement of right ventricular active-fixation pacing leads.

Carbachol improves secretion in the early phase after rabbit submandibular gland transplantation.

OBJECTIVES: To investigate the changes in the muscarinic receptor signaling pathway with submandibular gland (SMG) transplantation and whether carbachol improves secretion in transplanted SMGs. MATERIALS AND METHODS: SMG autotransplantation was performed in a rabbit model. Carbachol (1 microM) was infused into the transplanted glands from postoperative day 1-7. The expression of the M1 and M3 muscarinic receptors, aquaporin-5 (AQP5), and phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2) was measured by RT-PCR, immunoblotting or immunofluorescence. The content of inositol 1, 4, 5-trisphosphate (IP(3)) was measured by radioimmunoassay. RESULTS: Salivary flow of the transplanted SMGs was decreased after transplantation. As well, the expressions of M1 and M3 receptors and their downstream signaling molecules, IP(3), p-ERK1/2 and AQP5, were all reduced. Atrophy of acinar cells was shown in transplanted glands. However, all these alterations were reversed after carbachol treatment for 7 days. Furthermore, carbachol directly increased the mRNA expression of AQP5 and phosphorylation of ERK1/2 in cultured neonatal rabbit SMG cells. CONCLUSION: A lack of acetylcholine and downregulation of the muscarinic receptor signaling pathway is involved in the early hypofunction of transplanted SMGs. Carbachol treatment could be a new therapeutic strategy to improve secretion and prevent the obstruction of Wharton's duct in the early phase after SMG transplantation.