Ecotoxicology ; methods ; Epigenesis, Genetic ; Gene-Environment Interaction ; Toxicogenetics ; methods

Objective To discuss the effectiveness of the second surgical procedure of adjacent segment degeneration after the first spinal fusion.Method 35 patients who had been performed spinal fusion in our hospital or had symptoms recurred or aggravated after 12 ～ 114 (42 ±35) months of the prior surgery were enrolled in this study.A second surgery was performed and intraoperative the intradiscal pressure of adjacent segments of degeneration and normal segments was measured.The VAS score systems were compared among prior surgery,3 months later and 2 years after the second surgery.Result The intradiscal pressure of adjacent segments after the cervical vertebra and lumbar vertebra fusion were [ (15 ± 4.6)cmH2O,(23 ±5.2)cmH2O],much higher than normal segments [ (3 ±2.3)cmH2O,(8 ±4.1)cmH2O](P ＜0.01).The VAS score systems of 3 months later and 2 years after the second surgery were [ (2.9 ±0.7),(2.0 ± 0.6) ],which were dramatically lower than the prior (7.8 ± 1.2) (P ＜ 0.01).In 12 ～ 46(31 ± 12) months of follow-up after the second procedure,X-ray and MRI showed that fusion segments reached nearly bone fusion,well decompressed and without nerve compression or other complications.Conclusion If recurrence of symptoms after spinal fusion were caused by adjacent segment degeneration,reoperation would guarantee good clinical outcome.

Objective To investigate the relationship between cardiac vagus nerves and changes of connexins(Cx)and intracellular gap junction(GJ)distribution pattern in superior vena cava(SVC)myosleeve in dog with atrial fibrillation(AF).Methods Twenty four hybrid dogs were divided into sham operation group(Sham group,n=8),SVC-AO fat pad removed group(RM group,n=8)and SVC-AO fat pad reserved group(RS group,n=8).In RM group and RS group,right atrial pacing was performed at a frequency of 500～650/min for 6 weeks to establish AF model.AF was induced by programmed stimulation or burst stimulation of atrial pacing.The expression and distribution of Cx40 and Cx43 in the SVC myosleeve tissue in three groups were analyzed by immunofluorescence staining.Transmission electron microscopy was used to observe the uhrastructural organization of gap junction(GJ).Results The rate of inducing sustained AF(＞ 15 min)in RS group was significantly higher than that in RM group (P ＜ 0.01).The expression of Cx40 and Cx43 in the SVC myosleeve in sham group and RS group were significantly higher than that in RM group(P ＜ 0.05).Furthermore,the expression of Cx40 and Cx43 in RS group were obviously higher than that in sham group(P ＜0.05).The ratio of end-to-end to side-to-side in RS group was lower than that in Sham group and RM group.Comparing with RM group,the channel of GJ became shorter and wider in RS group(P ＜0.05).Sarcomere was dissolved and mitochondrion showed vacuole degeneration in RS group.Conclusion The remodeling of Cx40 and Gx43 in SVC myosleeve tissue may be mediated by vagus nerves.It is conducive to the maintenance and stability of AF.However,this effect can be weakened by removing SVC-AO fat pad of canine.

Objective To assess the proficiency of water monitoring laboratory at rural, county, and provincial levels in Guangdong province, to ensure the province's drinking water monitoring results accurate and reliable. Methods State quality of certified reference materials as water arsenic, fluoride and chloride of 90 copies each were numbered and distributed to 90 monitoring laboratories in the province for testing, The measurement results of the participatory labs were evaluated through normative values and expanded uncertainty, and were compared with those of robust statistics method. Results All participatory labs had timely feedback of their measurement results. The qualified rate was higher when arsenic was tested by hydride generation atomic fluorescence spectrometry and zinc-new silver salt of sulfuric acid spectrophotometric system, while fluoride and chloride by ion chromatography. The average qualified rates of water arsenic, fluoride and chloride of the province's rural drinking water quality monitoring laboratory were 66% (59/90), 72% (65/90) and 72% (65/90), respectively.Seven participatory labs failed the proficiency testing of all three analytes and unqualified rate was 7.8% (7/90)among the ninety participated monitoring labs. The qualified rates of robust statistics method for arsenic fluoride and chloride were greater than those evaluated by the expanded uncertainty, and large deviations with small sample sizes. Conclusions The testing ability of drink-water monitoring labs in Guangdong province has improved.However, by comparison with the requirements of national quality control and testing skills, there is still a gap. It is suggested that internal quality control be included in routine inspeetion to improve laboratory testing technology.

Objective To summarize the clinical features of Chinese patients with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes ( MELAS).Methods A total of 190 patients with MELAS who presented to Peking University First Hospital between 1997 and 2015 were recruited.Among 190 patients, 175 were identified carrying mitochondrial DNA mutations, and the remaining 15 patients were diagnosed by muscle biopsy.The clinical features, including predisposing factors of stroke-like episodes, the onset symptoms and frequencies of various manifestations were analyzed and reported.Results In our cohort of MELAS patients, the male-to-female ratio was 1.44∶1.The median age of onset was 14 years ( from 7 months to 45 years).The peak onset ages were 8-12 years.The median onset age of the first stroke-like episode was 16 years ( from 1 to 53 years ).There were 66 ( 46.15%) patients who had predisposing factors before the onset, and fatigue and upper respiratory tract infection were the most common predisposing factors of stroke-like episodes in these patients ( 37.88%, 25/66 and 34.85%, 23/66, respectively).Other predisposing factors included emotional agitation, drinking alcohol, trauma, withdrawal of antiepileptic drugs, being frightened, satiation and hunger.Stroke-like episodes appeared in 70.53%(134/190) patients as an onset symptom and developed in all patients with disease progression.The neurological manifestations included seizure ( 89.42%, 169/189 ) , mental retardation or dementia (82.87%, 150/181), headache (74.30%, 133/179), hemianopia or cortical blindness (67.72%, 107/158), exercise intolerance (50.87%, 88/173), hemiplegia or hemianesthesia (47.44%, 74/156), sensorineural deafness (46.20%, 85/184), aphasia (39.47%, 60/152), behaviour disorder (17.71%, 31/175) and ophthalmoplegia ( 9.60%, 17/177 ).The manifestations of extra-nervous systems included hirsutism (67.57%, 100/148), vomiting (65.58%, 101/154), fever (62.07%, 90/145), short stature (45.32%, 63/139), diarrhea or constipation (43.48%, 70/161), low body mass index (26.62%, 37/139), diabetes mellitus (20.79%, 37/178) and kidney disease (3.16%, 6/190).Conclusions The majority of the patients in this study have the disease onset during childhood.There are more male MELAS patients than females.Most common clinical manifestations are seizure, mental retardation or dementia, headache, cortical blindness, hirsutism, vomiting and fever in this patient group.

OBJECTIVETo investigate the biological effects of overexpression of the human DNA polymerase (pol-beta) on cellular response to DNA damage.

METHODSThe cell strain HLFbeta from the stable overexpression of the human pol-beta was contaminated with methyl methanesulfonate (MMS) for investigating the effects of the pol-beta on the cellular responses to DNA damage on the aspects such as the DNA damage, the cell cycle and the induced mutation rate.

RESULTSThe cell HLFbeta from the stable overexpression of the human pol-beta was obtained through the screening. The cellular response to DNA damage of HLFbeta induced by the MMS in the intermediate and high dosage group (ranging from 0.5 to 0.8 mmol/L) was significantly lower than that in the control group. The analysis for the cell cycle distribution showed that both the two types of cells contaminated by MMS had retardation at G(2) phase. In the HLFbeta group, the cells had the obvious G(2) phase retardation and 49.0% of the cells were retarded at G(1) phase as well when the MMS was increased to 0.5 mmol/L while in the control, only 20.1% of the cells were retarded at the G(1) phase when the same dosage of MMS was administered. Moreover, the MMS-induced mutagenesis in HLFbeta was increased from 4.5 x 10(-6) to 8.2 x 10(-6), significantly higher than that in the control group (P < 0.05).

CONCLUSIONHigh Pol-beta level decreases cellular DNA damage induced by MMS. Nevertheless, the overexpression of Pol-beta can also increase error-prone DNA synthesis during DNA repair process.

Cell Cycle ; drug effects ; genetics ; Cell Line ; DNA Damage ; genetics ; physiology ; DNA Mutational Analysis ; DNA Polymerase beta ; biosynthesis ; genetics ; DNA Repair ; Dose-Response Relationship, Drug ; Humans ; Methyl Methanesulfonate ; toxicity ; Mutagens ; toxicity ; Mutation

OBJECTIVETo construct pEGFP-C1-T vector, an eukaryotic expression plasmid of hMTH1 gene antisense RNA.

METHODSThe conservative region of hMTH1 gene was amplified by RT-PCR after total RNA being extracted from human embryo lung fibroblast (HLF) and then cloned into pGEM-T vector. After the recombinant plasmid was certified by DNA sequencing, the conservative region of hMTH1 gene was inserted into pEGFP-C1 vector reversedly and pEGFP-C1-T vector was constructed. The efficiency of antisense inhibition was verified by Western blotting after cell transfection.

RESULTS423 bp fragment including conservative region of hMTH1 gene was obtained by RT-PCR. After cloned by pGEM-T vector and certified by DNA sequencing, pEGFP-C1-T vector was successfully constructed by means of recombinant DNA technology. Additionally pEGFP-C1-T vector could efficiently decrease hMTH1 protein level by 46%.

CONCLUSIONThe efficient expression vector of hMTH1 gene antisense RNA, pEGFP-C1-T has been constructed successfully.

DNA Repair Enzymes ; Genetic Vectors ; genetics ; Humans ; Phosphoric Monoester Hydrolases ; genetics ; Plasmids ; RNA, Antisense ; biosynthesis ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo construct DNA double-strand break (DSB) repair protein hKu70 deficient cell strain and to observe its biological characters for studying the functions of hKu70 gene and the effects of occupational harmfulness factors on DSB repair.

METHODSHuman lung fibroblasts (HLF) were transfected with the eukaryotic expression plasmids of hKu70 gene antisense RNA (pEGFP-C1-K) to construct hKu70 protein deficient cells (named as "HLFK"). The protein expression levels of hKu70 gene in HLFC and HLFK were detected by the Western blotting to estimate the effects of antisense inhibition. Morphology, growth character and growth status in soft agar of transfected HLFK were observed.

RESULTSpEGFP-C1-K vector was successfully expressed in HLF. The protein expression level of hKu70 gene in HLFK was decreased by 42% as compared with that in HLFC. No obvious changes of the biologic characters were observed in HLFK.

CONCLUSIONThe hKu70 protein deficient cell strain was successfully constructed. The hKu70 protein deficiency alone didn't induce obvious changes of the biological characters in HLFK.

Antigens, Nuclear ; analysis ; Cell Division ; DNA Damage ; DNA Helicases ; DNA Repair ; DNA-Binding Proteins ; analysis ; deficiency ; Humans ; Ku Autoantigen ; RNA, Antisense ; Transfection

OBJECTIVETo study DNA and nucleus damage in human embryo lung fibroblast (HLF) exposed to hydroquinone (HQ) and its genotoxicity.

METHODSHLF were treated with HQ (0, 10, 20, 40, 80 micro mol/L, respectively) for 3 h and DNA damage was detected by comet assay. HLF was also treated with the same concentrations of HQ for 1 h and micronucleus test was performed after they were cultured for 24 h.

RESULTSComet assay showed that percentage of cells with tails in each groups treated with varied doses of HQ was 12%, 19%, 42%, 79% and 95%, respectively, with mean tail length of 7.87, 9.35, 11.03, 19.28 and 23.32 micro m, respectively, in an obvious dose-dependent manner (P < 0.05). Very significant increase in percentage of cells with tails and length of their comet tail were observed in those groups treated with HQ of 20, 40 and 80 micro mol/L (P < 0.01). And, proportion of high and severe DNA damage increased with dose of HQ. HQ could also induce formation of micronucleus and abnormal nucleus in all groups treated by varied doses of HQ, with rates of micronucleus and abnormal nucleus of 2%, 3%, 10%, 9% and 15%, and 6%, 7%, 16%, 27% and 28%, respectively, in a significant dose-dependent manner. There was significant increase in rates of micronuclei and abnormal nuclei in cells treated with HQ at doses of 20, 40 and 80 micro mol/L (P < 0.05).

CONCLUSIONSExposure to HQ could cause DNA and nucleus damage inducing genotoxic effects on HLF.

Cell Nucleus ; drug effects ; Comet Assay ; DNA Damage ; drug effects ; Embryo, Mammalian ; Fibroblasts ; cytology ; Humans ; Hydroquinones ; toxicity ; Lung ; cytology ; Micronucleus Tests