OBJECTIVETo pursue insulin and islet-transplantation replacement therapy for type 1 diabetes based on engineered human non-beta cells which secrete mature insulin.

METHODSHuman proinsulin cDNA was cloned from its genomic gene and mutated by overlap extension PCR, introducing furin consensus cleavage sequences (Arg-Xaa-Lys/Arg-Arg). An expression vector encoding a genetically modified human proinsulin cDNA was generated and transduced to Hela, 293, and L02 cells by lipofectin-mediated DNA transfection. Following G418 screening, the surviving L02 cells were selected and enriched. Insulin levels in the supernatant and cells were evaluated using radioimmunoassay and immunofluorescence staining.

RESULTSThree sites in the insulin gene were mutated simultaneously. Insulin gene modified cells were able to express insulin at different levels: 8.45 - 188.00 microIU/24 h/2.0 x 10(6) Hela cells and 159.88 - 242.14 microIU/24 h/2.0 x 10(6) 293 cells for transient expression, and 2.56 - 61.95 microIU/24 h/2.0 x 10(6) from several L02 clones screened with G418. No insulin was released by control cells. Furthermore, immunofluorescence staining confirmed that proinsulin was stored as vacuoles in the cytoplasm of L02 cells.

CONCLUSIONA correctly mutated human proinsulin cDNA was obtained successfully, transfected and expressed efficiently in non-beta cells, lending support to the study of somatic gene therapy in diabetes mellitus.

Cell Line ; Chromatography, High Pressure Liquid ; DNA, Complementary ; genetics ; Fluorescent Antibody Technique ; Genetic Vectors ; genetics ; HeLa Cells ; Humans ; Insulin ; genetics ; metabolism ; Proinsulin ; genetics ; Radioimmunoassay ; Transfection

OBJECTIVETo explore the minimum observed adverse effect level(LOAEL) and intensity of pathogenesis of tin mine dust.

METHODSA cohort study design with retrospective assessment of exposure was used. Selected 4,471 male tin miners who were exposed to tin at least one year during 1960 to 1974 and were compared with 4,797 pottery dust exposed workers in the same way designed. Statistical analysis system SAS, PROC LIFETEST were used to perform the non-parameter calculation by Life Table method.

RESULTSTin mine cohort subjects were followed up to December 31, 1994. The percentage of miners who developed silicosis was 21.7% (971/4,471). 81% of the patients had been exposed to dust before 1958. The cumulative total dust exposure(CTD) was significantly correlated with silicosis risk. The risk of silicosis was 0.012 when CTD was less than 50 mg/m-3.year-1. The risk of silicosis was increased to 0.971 when CTD was beyond 400 mg.m-3.year-1. However, the risk of silicosis was only 0.369 for dust exposed workers in pottery factories when CTD was beyond 400 mg.m-3.year-1.

CONCLUSIONThere was significant relationship between cumulative dust exposure and the incidence of silicosis in tin exposed workers. And silicosis induced by tin mine dust is more serious than the pottery dust.

Cohort Studies ; Dust ; Humans ; Mining ; Occupational Exposure ; adverse effects ; Silicosis ; etiology ; Tin

BACKGROUND: If high-intensity resistance training is used as a rehabilitation measure after musculoskeletal injury, it may be aggravated by factors such as pain. The blood flow restriction training can achieve high-intensity resistance training through low-intensity resistance training, which can accelerate the recovery of patients. OBJECTIVE: To elaborate the current situation of blood flow restriction training as a new way to accelerate musculoskeletal rehabilitation at home and abroad. METHODS: The first author searched the related studies on the musculoskeletal rehabilitation of blood flow restriction training included in PubMed, Cochrane Library and CNKI from January 2002 to October 2018. The keywords were "blood flow restriction training; Kaatsu training; low intensity resistance training; safety; musculoskeletal rehabilitation; knee osteoarthritis; patellofemoral pain; knee joint injury; ankle joint injury; quantitative difference" in English and Chinese. RESULTS AND CONCLUSION: Blood flow restriction training, as a new treatment method, can reduce the training load and achieve the effect similar to the high-intensity resistance training by designing an individualized and precise rehabilitation scheme. Additionally, it can make the resistance training happen in advance due to its unique advantage, thus contribute to rapid rehabilitation. However, this method is mostly applied to lower limb injuries, and its feasibility for other parts still needs a further investigation.