Chromatography, Gas ; Humans

China ; epidemiology ; Humans ; Occupational Diseases ; epidemiology ; prevention & control ; Surveys and Questionnaires ; Trimethyltin Compounds ; analysis ; poisoning

This article described the concept of the professional ethics and discussed the significance of the existence and construction of professional ethics on medical journal editors. The professional ethics on medical journal editors could be beneficial to correctly understand the ethical problems of medical journal editors and to promote the medical journal editors' role localization. It is very important to construct the Standardization of medical journal editors' behavior.

Air ; analysis ; Chromatography, Gas ; methods ; Ethylene Oxide ; analysis ; Furans ; analysis ; Methylene Chloride ; analysis ; Workplace

Objective To explore the residual undifferentiated mouse embryonic stem cells (ESCs) in embryoid bodies. Methods Mouse R1 and Oct-4-GFP transgenic ESCs were firstly cultured in suspension to form embryoid bodies (EBs). Twenty days later, EBs were digested into single cells and then re-plated in standard ESC culture condition. The morphology of residual undifferentiated cells in EBs was observed, and surface makers and in vitro redifferentiation potency of residual cells were examined by flow cytometry and immunofluoreseent staining. The residual cells were expanded and subcutaneously injected into nude mice, and the specimens were harvested from the injection site for histological analysis 6 weeks after injection. Results There were residual undifferentiated ESCs in EBs differentiated for 20 days, which displayed clonal morphology and expressed undifferentiated cell markers of ESCs, including SSEA1, CD31, CD9 and Oct-4. The cells could be differentiated to form EBs again, and could be re-expanded from secondary EBs. The residual cells were able to form teratoma at the injection site, and mature endoderm, mesoderm and ectoderm tissues could be found in teratoma tissues. Conclusion There are residual undifferentiated ESCs after differentiation of ESCs into EBs. The residual ESCs can differentiate again in vitro and in vivo, and can residue again in the in vitro differentiation.

BACKGROUNDHuman urotensin II (UII) is the most potent mammalian vasoconstrictor identified so far. Our previous study showed that UII is a potent mitogen of airway smooth muscle cells (ASMC) inducing ASMC proliferation in a dose-dependent manner. The signal transduction pathway of UII mitogenic effect remains to be clarified. This study was conducted to investigate the signal transduction pathway in the proliferation of ASMC induced by UII.

METHODSIn primary cultures of rat ASMCs, activities of protein kinase C (PKC), mitogen-activated protein kinase (MAPK) and calcineurin (CaN) induced by UII were measured. The effect of CaN on PKC and MAPK was studied by adding cyclosporin A (CsA), a specific inhibitor of CaN. Using H7 and PD98059, inhibitors of PKC and MAPK, respectively, to study the effect of PKC and MAPK on CaN. The cytosolic free calcium concentration induced by UII was measured using Fura-2/AM.

RESULTSUII 10(-7) mol/L stimulated ASMC PKC and MAPK activities by 44% and 24% (P < 0.01), respectively, after incubating for 20 minutes. It increased CaN activity in a time-dependent manner, being 1.68 times as that of control for 24 hours (P < 0.01). It promoted the cytosolic free calcium concentration increase of 18% (P < 0.01). CsA 10(-6) mol/L and H7 50 micromol/L inhibited UII-stimulated CaN activity by 45% (P < 0.01) and 21% (P < 0.05), respectively, while PD98059 50 micromol/L had no effect on CaN activity (P > 0.05). CsA 10(-6) mol/L inhibited UII-stimulated PKC activity by 14% (P < 0.05), while having no effect on MAPK activity (P > 0.05).

CONCLUSIONSUII increases cytosolic free calcium concentration and activates PKC, MAPK and CaN. The signal transduction pathway between PKC and CaN has cross-talk.

Animals ; Calcineurin ; metabolism ; Cells, Cultured ; Enzyme Activation ; Mitogen-Activated Protein Kinases ; metabolism ; Mitogens ; pharmacology ; Myocytes, Smooth Muscle ; cytology ; Protein Kinase C ; metabolism ; Rats ; Signal Transduction ; physiology ; Trachea ; cytology ; Urotensins ; pharmacology

Adult ; Dandy-Walker Syndrome ; complications ; pathology ; Humans ; MELAS Syndrome ; complications ; pathology ; Magnetic Resonance Imaging ; Male

OBJECTIVETo establish a detection method for trimethyltin chloride in urine by the Head space-GC.

METHODAfter derivatizing trimethyltin chloride, the urines was separated by the head space-gc, and then the trimethyltin chloride detected qualitatively and quantificationally.

RESULTSIn the concentration range of 0.02 ∼ 0.40 mg/L urinary trimethyltin chloride, showed a quadratic, r = 0.9992, detection limit was 0.005 mg/L, the relative standard deviation was 1.9% ∼ 2.5%, recovery was 92.0% to 100%, the urine samples can be saved at least 90 days in -18°C refrigerator.

CONCLUSIONThe instrument, reagents involved in the detection require low, the operations to processing samples are simple, high sensitivity, less interference, good reproducibility, and suitable for quantitative and qualitative analysis, convenient to promotion.

Chromatography, Gas ; methods ; Humans ; Trimethyltin Compounds ; urine ; Urinalysis ; methods

OBJECTIVETo explore the hepatic toxicity and the exposure biomarkers of N, N-Dimethylacetamide.

METHODSOne hundred forty five objects were chosen by stratified random sampling method. The investigation was performed using questionnaire and physical examination. The air concentrations of DMAC in the workshops were monitored. The urine samples were collected and analyzed after work everyday or at the weekend. The correlation between the air concentrations of DMAC in the workshops and the concentrations of urinary NMAC wee analyzed by regression.

RESULTSThe air concentration of DMAC in the spinning workshop was higher than others. The morbidity of abnormal hepatic function was 12.4%, 61.1% of workers with abnormal hepatic function appeared in one year after exposure to DMAC in the workshops ( r=0.44, P<0.01).

CONCLUSIONThe abnormal heptic function was found in workers exposed to DMAC for short period. The concentration of urinary NMAC can serve as the exposure biomarker of DMAC.

Acetamides ; toxicity ; urine ; Adolescent ; Adult ; Air Pollutants, Occupational ; analysis ; Biomarkers ; urine ; Environmental Monitoring ; Humans ; Liver Function Tests ; Male ; Middle Aged ; Occupational Exposure ; Surveys and Questionnaires ; Workplace ; Young Adult

OBJECTIVETo establish a method to detect N-methylacetamide (NMAC) concentration in urine of workers occupationally exposed to NMAC with directly injecting the sample into capillary gas chromatography.

METHODSAfter frozen urine samples were isolated from precipitation by centrifugation, the aliquot of supernatant was pretreated by protein precipitation with dilution of methanol. The methanol supernatant was separated by Polyethylene Glycol (PEG) capillary columns and detected by nitrogen phosphorous detector (NPD).

RESULTSGood linearity was obtained in the concentration range of 1.0 ∼ 250 mg/L. The correlation coefficient was 1.0000. The minimum detection limit of NMAC in urine was 0.2 mg/L. The method recovery rates were 96.0% ∼ 99.4% at three different concentrations. The mean recovery rate was 97.8%. The relative standard deviations (RSD) of intra- and inter-day were between 1.5% ∼ 3.4%.

CONCLUSIONThe method was simple, rapid, selective and sensitive and was applicable to detect the urinary NMAC concentration for monitoring occupational exposure levels.

Acetamides ; urine ; Chromatography, Gas ; methods ; Environmental Monitoring ; methods ; Humans ; Occupational Exposure ; analysis