Construction and application of a random forest-based classification model for DNA double-strand break induced by ionizing radiation / 中华放射医学与防护杂志

Objective:To construct a random forest classification model of DNA double strand breaks (DSB) induced by ionizing radiation and investigate the genome-wide distribution of DSB.Methods:The GRCh38 reference genome was divided into 50 kilobase fragments. Then these genomic fragments were separated into low-level or high-level regions of ionizing radiation-induced DSB according to the sequencing data of MCF-7 cells. The data of eight epigenetic features were used as input. Two thirds of the data were randomly assigned to the training set, and the rest of the data was assigned to the test set. A random forest classification model with 100 decision trees was constructed. The importance of epigenetic features in the classification model was analyzed and displayed.Results:The accuracy score of the random forest classification model on the test set was 99.4%, the precision score was 98.9% and the recall score was 99.9%. The area under the receiver operating characteristic curve was 0.994. Among the eight epigenetic features, H3K36me3 and DNase markers were the most important variables. The enrichments of the two markers in DSB high-level regions were much higher than those in DSB low-level regions.Conclusions:The random forest classification model could precisely predict the genome-wide levels of DSB induced by ionizing radiation in the 50 kilobase window based on epigenetic features. Analysis revealed that these DSB might primarily distribute in the actively transcribed sites in the genome.

A study to construct three prokaryotic expression vectors and its expression in adenosine deaminase / 国际检验医学杂志

Objective To express adenosine deaminase protein by molecular cloning technique.MethodsTotal RNA was extracted from human leukocytes and the cDNA was obtained by reverse transcription.Whereupon the cDNA was used as a template to amplify adenosine deaminase gene by polymerase chain reaction (PCR) and then integrated it into three prokaryotic plasmids pET-28 b, pET-32 a (+) and pHSIE.The plasmid with the correct sequencing was transformed into E.coli BL21 (DE3) by CaCl2 method for the protein expression.The expression activity of these fusion proteins were detected by Western-blot and SDS-PAGE, with the optimized expression conditions.Results Complete fusion of target gene and three prokaryotic plasmids was observed through sequencing.The expressed and accurate ADA protein was identified by Westernblot and SDS-PAGE.The optimal expression conditions were observed:the protein expression would be induced with 0.4 mmol/L IPTG and incubated at 16℃for 24 hours.Conclusion The prokaryotic vectors of adenosine deaminase (BL21+pET-28 b+ADA, BL21+pET-32 a+ADA, BL21+pHSIE+ADA) were successfully constructed and efficiently expressed.

Effect of propofol on apoptosis of cortical astrocytes isolated from neonatal rats / 中国药理学通报

Aim To study the effects of propofol on apoptosis of cortical astrocytes isolated from neonatal rats.Methods Pure astrocytes(AST)were obtained from the cultured cerebral cortical cells and identified by the GFAP stain technology in neonatal rats.AST cells were treated with different concentrations of propofol(0,10,30,90 μmol·L-1)for 8 hours.Cell viability was measured by MTT method,and the apoptosis was detected by Annexin V/PI double staining.Cytochrome C(cyt-C)leakage was detected by Western blot.Caspase-3 and caspase-9 activities were measured by spectrophotometry.Results AST cells were administered with different concentrations of propofol(0,10,30,90 μmol·L-1)for 8 hours.It decreased the survival rate in a concentration-dependent manner,induced the leakage of cyt-C in mitochondria,up-regulated the expression of pro-apoptotic protein caspase-3 and caspase-9,and induced AST apoptosis.Conclusion Propofol induces the apoptosis of astrocytes in neonatal rat cortex in vitro,which may be related to the activation of mitochondria apoptosis pathway induced by mitochondrial cyt-C release.

Relationship of blood glucose, blood lipids, blood uric acid and fibrinogen level, and prognosis of acute lacunar cerebral infarction patients / 中国基层医药

ObjectiveTo investigate the relationship of blood glucose,blood lipids,serum uric acid,fibrinogen level and prognosis of patients with acute lacunar cerebral infarction.MethodsClirical data of 127 cases with acute lacunar cerebral infarction were retrospectively analyed.Patients with normal blood glucose,blood lipid,uric acid and fibrinogen level were enrolled into A group of 64 cases,63 cases with abnormal levels were selected as group B,an average of 2 years of follow-up,observing the two groups of neurologic,re-infarction incidence and prevalence of vascular dementia were obsenved in two groups.ResultsAfter 4 weeks of treatment,A group of neural function defect score(9.6 ±7.3) was significantly lower than group B( 14.3 ±7.4) (t =3.8696,P ＜0.05) ;95.4％ total effective rate in A group was significantly higher than B group of 82.0％ ( x2 =5.8623,P ＜ 0.05 ).After an average follow-up of 2 years,A group of recurrent cerebral infarction rate( 18.8％ ),vascular dementia rates(7.8％ ),were significantly lower than group B(28.6％),17.5％(11/63)(x2 =6.5421,5.9623,P＜0.05).ConclusionA number of abnormal serum biochemical indexes had a significant impact on short and long-term prognosis of acute lacunar cerebral infarction.

Effects of pre-treatment on Cu2+ absorption of Penicillium janthinellum strain GXCR / 生物工程学报

In order to effectively increase capacity of Cu2+ absorption by Penicillium from Cu2+-containing aqueous solution and to study the mechanisms of absorption, effects of eight pre-treatment methods on Cu2+ absorption of Penicillium janthinellum strain GXCR were compared. The results showed that the efficiency of Cu2+ absorption obviously increased through pre-treatment by homogenization, homogenization-basification (NaOH), oven dry (80 degrees C), homogenization-salinification (NaCl), homogenization-detergent and homogenization-polarization (C2H6SO), but significantly decreased after acidification pretreatment with H2SO4. In comparison with the previous reports, the pretreatment in a homogenization-NaOH way could more efficiently enhance the Cu2+ absorption capacity of this fungus. Homogenization-basification (0.5 mol/L NaOH) increased Cu2+ biosorption by 47.95%. The Cu2+ absorption of the mycelia treated by homogenization-basification followed Langmuir isotherm equation, suggesting a surface absorption process. After four cycles of absorption-desorption, mycelia pretreated by homogenization-alkalization still had 70.82% of Cu2+ biosorption efficiency. Infrared reflectance analysis indicated that alkalization treatment made marked effects on molecular groups of C-H, C=O, and C=O in COOH on the mycelial surfaces, and -OH was a key Cu2+-binding group. It is therefore suggested that the Cu2+ absorption by the GXCR is likely to be a chemical absorption process through Cu2+ binding with -OH group on the mycelia.

Cu and Fe bioleaching in low-grade chalcopyrite and bioleaching mechanisms using Penicillium janthinellum strain GXCR / 生物工程学报

Bioleaching of Cu and Fe in low-grade chalcopyrite using Penicillium janthinellum strian GXCR was studied. As a result, shaking bioleaching was more efficient than submerged bioleaching; Cu bioleaching was much better than Fe bioleaching; under conditions of optimum carbon source (10% sucrose, W/V), optimum nitrogen source (1.5% NaNO3, W/V), shaking bioleaching and the optimum combination of conditions (initial pH 6.0 in leaching media, 5% (W/V) 200-mesh ore and initial inocula of 3.0x10(5) conidia/mL), Cu bioleaching efficiency reached 87.31% (W/W). One of the most important factors affecting Cu bioleaching in shaking bioleaching was the initial pH in leaching media (F > F0.05). The major organic acids for Cu and Fe bioleaching were citric and oxalic acids, respectively. Low bioleaching efficiency by submerged bioleaching was due to low production of citric and oxalic acids. The mechanisms employed by the GXCR in Cu bioleaching included biochemical functions of citric and oxalic acids as well as ore crack caused by mechanical power generated from mycelial growth.

Invance sling in treating children incontinence as neurogenic sphincteric incompetence (report of 2 cases) / 中华泌尿外科杂志

Objective To evaluate the clinical effectiveness of the Invance sling in treating children incontinence caused by neurogenic sphincteric incompetence. Methods Two children were treated with Invance sling for their neurogenic sphincteric incompetent incontinence because of congenital myelodysplasia.Both were male,aged of 9 and 10,respectively. Results Two patients were followed up of 12 and 14 months.Both patients micturated once each 2～4 hours with 1～2 episode of incontinence by chance in the daytime and without urinary pad.The maximum bladder capacities were 163 ml and 223 ml pre-operatively and those were 164 ml and 230 ml post-operatively,the retrograde maximum urethral pressures or retrograde leak point pressures were 37 cmH_2O and 27 cmH_2O pre-operatively while those were 45 cmH_2O and 37 cmH_2O post-operatively,maximum urethral closing pressures were 37 cmH_2O and 26 cmH_2O pre-operatively while those were 40 cmH_2O and 37 cmH_2O post-operatively,the functional urethral lengths were 2.5 cm and 3.0 cm pre-operatively while those were 3.5 cm and 4.0 cm post-operatively,the post-voiding residual urine volumes were 40 ml and 30 ml pre-operatively while those were 6 ml and 25 ml post-operatively.Post-operative voiding cystourethrography demonstrated that it was pressed to narrow at the suspended in the bulbous urethra segment. Conclusions The sling in treating children neurogenic sphincteric incompetent incontinence is simple,mini-invasive.It can increase the urethral resistance and continence better.But it has specific indication and should be applied prudently.