[Survival analysis of different kinds of tyrosine kinase inhibitors in the treatment of patients with epidermal growth factor receptor mutated non-small cell lung cancer and leptomeningeal metastasis].

Objective: To explore the prognosis of patients with leptomeningeal metastasis (LM) and epidermal growth factor receptor mutated (EGFRm) non-small cell lung cancer (NSCLC) treated with different kinds of tyrosine kinase inhibitors (TKIs). Methods: From January 2016 to June 2021, the clinicopathological data of 70 patients confirmed by histologically or cytologically EGFRm LM who received different types of TKIs in Cancer Hospital of Chinese Academy of Medical Sciences were retrospectively analyzed. According to treatment patterns, patients were divided into the first-and second-generation EGFR-TKIs treatment group and the third-generation EGFR-TKIs treatment group [Osimertinib 80 mg once a day], and the prognosis and prognostic factors (with Cox proportional hazards model) of patients in different treatment group were assessed. The next-generation sequencing (NGS) of paired samples of cerebrospinal fluid (CSF) and plasma from 64 patients at the time of LM diagnosis was performed simultaneously. Results: There were 20 males and 50 females in 70 EGFRm NSCLC patients with LM. The age ranged from 35 to 69 years, with a median age of 56 years. A total of 24 patients received the first-and second-generation EGFR-TKIs treatment, and 46 received the third-generation EGFR-TKIs treatment. Twenty-four patients developed disease progression on the first-and second EGFR-TKIs treatments, followed by treatment with the third-generation EGFR-TKIs (Osimertinib) in 12 cases, chemotherapy or anti-angiogenesis therapy in 4 cases, and the optimal supportive treatment in 8 cases. Among the 70 patients, 18 had partial response (PR), 48 had stable disease (SD), and 4 had progressive disease (PD). The objective response rate (ORR) and disease control rate (DCR) were 26% (18/70) and 94% (66/70), respectively. The median follow-up time was 16.5 months. The median progression-free survival (PFS) was 5.3 months(95%CI: 2.8-7.8)in the first-and second-generation EGFR-TKIs and 10.8 months (95%CI: 7.9-13.6) in the third-generation EGFR-TKIs, and the difference was statistically significant (P=0.019). The median overall survival (OS) was 14.9 months (95%CI: 9.7-20.0) and 15.7 months (95%CI: 13.3-18.1) in the two groups, respectively, but no statistical differences was observed (P=0.713). Univariate analysis showed that the PFS of patients with EGFRm LM were related to gender and different types of EGFR-TKIs (P˂0.05). Multivariate analysis demonstrated that male (HR=2.30, 95%CI: 1.31-4.03, P=0.004) and the first-and second-generation EGFR-TKIs (HR=2.03, 95%CI: 1.20-3.41, P=0.008) were independent risk factors for PFS in patients with EGFRm LM. The EGFR mutation was detected in 61 (95%) CSF and in 27 (42%) plasma samples. Conclusion: In EGFRm NSCLC patients with LM, the dose of Osimertinib 80 mg (once a day) has a significant PFS benefit compared with the first-and second-generation EGFR-TKIs.

Comparative genome-wide methylation analysis of longissimus dorsi muscles in Yorkshire and Wannanhua pigs.

DNA methylation was one of the earliest discovered epigenetic modifications in vertebrates, and is an important epigenetic mechanism involved in the expression of genes in many biological processes, including muscle growth and development. Its effects on economically important traits are evidenced in reported differences in meat quality traits between Chinese indigenous pig breeds (Wannanhua pig) and Western commercial pig breeds (Yorkshire pig), and this presents a unique model for analyzing the effects of DNA methylation on these traits. In the present study, a whole genome DNA methylation analysis was performed on the two breeds using methylated DNA immunoprecipitation. GO functional enrichment and pathway enrichment analyses identified differentially methylated genes primarily associated with fatty acid metabolism, biological processes of muscle development and signaling pathways related to muscle development and pork quality. Differentially methylated genes were verified by sodium pyrosequencing, and the results were consistent with the sequencing results. The results of the integrative analysis between DNA methylation and gene expression revealed that the DNA methylation levels showed a significantly negative correlation with gene expression levels around the transcription start site of genes. In total, 41 genes were both differentially expressed and methylated; these genes were related to fat metabolism, lipid metabolism and skeletal muscle development. This study could help further explore the molecular mechanisms and phenotypic differences in pig growth and development among different breeds.

[Study on the prognostic value of preoperative anti hepatitis B virus therapy in patients with hepatocellular carcinoma complicated with microvascular tumor thrombus and establishment of survival prediction model].

Objective: To explored the effect of preoperative antiviral therapy on the prognosis of microvascular tumor thrombi patients, and to established a prognostic prediction model for these patients after radical resection of liver cancer. Methods: The clinicopathological and survival data of hepatocellular carcinoma patients with microvascular tumor thrombus who underwent radical resection in the Third Affiliated Hospital of Sun Yat-sen University from January 1, 2013 to December 31, 2015 were retrospectively collected. Kaplan-Meier method was used to calculate the survival curve, and log-rank test was used to compare the prognosis of patients with and without antiviral treatment before operation. Univariate and multivariate Cox proportional hazard regression model was used to screen predictive factors. R software was used to make predictive nomogram, and discrimination and calibration degree were used to evaluate the prediction model. Results: Among all 153 patients, 22 were female and 131 were male, aged (51.3±11.7) years. The preoperative antiviral therapy significantly improved overall survival and recurrence-free survival (χ2=41.423, 54.389; both P<0.001). According to the results of multivariate and regression analysis, preoperative antiviral therapy (HR=0.301,95%CI:0.171-0.532,P<0.001), alpha fetoprotein (HR=1.226,95%CI:1.157-1.776,P=0.032) and tumor size (HR=1.008,95%CI:1.001-1.016,P=0.02) were important prognostic factors for overall survival. The area under curve value of 3-year survival prediction model was 0.749(95%CI: 0.712-0.782), and that of 5-year survival prediction model was 0.755(95%CI: 0.724-0.793), with good calibration. Conclusions: Preoperative anti hepatitis B virus(HBV) therapy can significantly improve the prognosis of patients with hepatocellular carcinoma complicated with microvascular tumor thrombus, we develope the prediction models of 3-year and 5-year survival rate that can improve the reference for clinical work and benefit patients.

[Analysis on job burnout status and its influencing factors among female workers of labor-intensive enterprises].

Objective: To analyze the status and its influencing factors of job burnout among female workers of labor-intensive enterprises. Methods: A total of 750 female workers from 5 labor-intensive enterprises in Guangdong Province were selected as the study subjects by random cluster sampling method in August, 2019. 665 valid questionnaires were collected, and the effective recovery rate was 88.67%. The Maslach Burnout Inventory-General Survey was used to assess job burnout and its influencing factors were analyzed. Results: Among 665 female workers, 429 (64.51%) found to have different levels of burnout, among which 380 (57.14%) were mild to moderate burnout and 49 (7.37%) were severe burnout. The comprehensive scores of job burnout in different age, marital status, current post working age, working time per week, personal monthly income, working system and occupational stress groups were statistically significant (P<0.01) . There were significant differences in the score of emotional exhaustion in different age, marital status, current working age, working time per week, personal monthly income and occupational stress groups (P<0.05) . There were significant differences in the dimensions of depersonalization in different age, weekly work time, personal monthly income, working system and occupational stress groups (P<0.05) . There were significant differences in the dimensions of low individual achievement in different education levels, weekly work time, working system and occupational stress groups (P<0.05) . Conclusion: The female workers of labor-intensive enterprises are generally have mild to moderate job burnout. The main influencing factors of job burnout are weekly work time and occupational stress.

[Development of the Core Occupational Stress Scale for occupational populations in China].

Objective: To develop the Core Occupational Stress Scale (COSS) for key occupational populations, and to assess the reliability and validity of COSS in China. Methods: According to the literature review, in-depth interview and expert evaluation, the item pool of COSS was established. A total of 20 981 employees (3 703 employees from 2018 and 17 178 employees from 2019) of manufacturing, medical, and traffic polices, etc. from Beijing, Tianjin, Shanghai, Chongqing, Jiangsu, Shandong, Zhejiang, Hunan, Guangdong and Hubei were investigated using convenient sampling of those participating in general or occupational health examination of the day. Item differential test and exploratory factor analysis (EFA) were used to screen items from the item pool; confirmatory factor analysis (CFA) was used to test structure validity; criterion and convergent validity were tested by Pearson correlation. Cronbach's α coefficient was used to test the reliability of the scale. Results: The EFA suggested a four-factor structure for a 17-item version of COSS, which were social support, organization and reward, demand and effort, and control. It explained 62.06% of the total variance and factor loadings ranged from 0.447 to 0.918. The CFA confirmed the hypothesized four-factor model (GFI=0.904, CFI=0.912, RMSEA=0.079). The COSS scores were positively correlated with burnout, depressive symptoms, and effort-reward imbalance scores with r ranging from 0.357 to 0.567 (P<0.05). The total COSS and each dimension of Cronbach's α coefficients were 0.772-0.896. Conclusions: The COSS has good reliability and validity and can be used as an occupation stress assessment for occupational populations in China.

[Cyto-inactivation instantly induced by microwave ablation on thyroid nodules].

Objective: To explore the effect of microwave ablation on thyroid nodules cell activity by the reaction of key enzyme of cell activation. Methods: From November 2017 to February 2018, 104 patients with 120 thyroid nodules underwent ultrasound-guided microwave ablation at Super-minimally Invasive Medicals, Shanghai International Medical Center, aged 14-55 years, 42 males and 62 females.Twice core needle biopsy were performed before and after thermal ablation.The specimen were using hematoxylin and eosin (HE) staining and enzyme histochemical staining with include succinate dehydrogenase (SDH) and nicotinamide adeninedinucleotide phosphate diaphorase (NADPH-d), respectively, and observe under microscope. Results: Enzyme histochemical staining showed that the positive rate of SDH and NADPH-d in the marginal region and transitional region were 100% before ablation, and were 0% immediately after ablation.The positive rate of SDH and NADPH-d histochemical staining in the same area before and immediately after ablation was statistically significant (P<0.05). Shortly after microwave ablation, the tissue structure and cell morphology showed no obvious alteration in HE stained sections, but in sections with enzyme histochemical staining, the activity of SDH and NADPH-d in ablated tissue disappeared.The accuracy rate of pathologic diagnosis was 100% after ablation. Conclusions: SDH and NADPH-d enzyme activity may be better in evaluating the short-term efficacy of microwave ablation of thyroid nodules than HE staining.

[Comparison of knowledge and behavior toward hearing protection among workers in different workplaces and its influence factors].

Objective: To compare the knowledge and behavior toward hearing protection among workers in different workplaces and investigate its influence factors. Methods: 2 manufacturing companies with obvious noise hazard in workplace were selected into the study. Health management level was distinguished through field investigation and verification. Questionnaire focus on basic knowledge of hearing health, acceptance level of noise hazard, comfort of wearing hearing protectors and atmosphere in workplace was designed and was used to investigate the knowledge and behavior toward hearing protection. Results: Hearing protectors that meet the level of protection are distributed throughout the workplaces. Although company A has a lower noise hazards level, the health management system was poorly executed. The proportion of workers persisting in wearing hearing protectors throughout the work shift in company A was lower than B (P<0.01) . Workers in company A intended to underestimate the noise level (P<0.01) and the health effect of hearing loss (P<0.01) . All the workers were worry about suffering from hearing loss (P>0.05) , but those in company B had more positive attitude toward the protection of hearing protector (P<0.01) and relied on the protector (P<0.01) . The awareness of protection, in turn, help workers adapt attitude and get used to wearing hearing protectors consciously in workplace (P<0.01) . Conclusion: Health management performance play a key role in help workers form good knowledge and behavior. To protect workplace health, employers need to creative a healthy supportive environment for workers.

Placenta percreta with colon involvement in a twin pregnancy: case report and literature review.

A case of a woman with twin pregnancy having placenta percreta involving the colon, showed hematochezia symptoms, experienced bleeding which caused the patient's mortality. Placenta percreta with bowel involvement is a very serious complication of pregnancy. Symptoms are very atypical and it is very difficult to diagnose.

[Obstetric outcome in pregnancy complained with pulmonary hypertension].

Objective: To identify whether pregnancy outcomes vary by the severity of pulmonary hypertension. Methods: A retrospective study was conducted on 78 cases of pregnancies complained with pulmonary hypertension who delivered in the First Affiliated Hospital, Sun Yat-sen University from 2006 to 2016.The selected cases were divided into three groups according to severity of pulmonary hypertension: mild pulmonary hypertension group (mild PAH group) was defined as a mean pulmonary artery pressure 30-49 mmHg, moderate pulmonary hypertension (moderate PAH group) as mean pulmonary artery pressure 50-69 mmHg and severe pulmonary hypertension (severe PAH group) as mean pulmonary artery pressure 70 mmHg or greater.The clinical features, risk pregnant complication, maternal and neonatal outcomes were described between these three groups.Analysis of variance, Chi-square test was used for statistical analysis. Results: The average age of mild, moderate and severe PAH group were (31±5) years old, (31±5) years old and (27±3) years old, respectively (P=0.050). The rate of natural fertilization (P=0.414), parity (P=0.527) and gestational age (P=0.165) were similar in these three groups. In 78 pregnancies with pulmonary hypertension, 64.9% of pregnancies in mild PAH group was NYHA Ⅰ, 50.0% of moderate PAH group was NYHA Ⅱ and 54.5% of severe PAH group was NYHA Ⅲ(P<0.001). There was no significant difference in the incidence of gestational diabetes mellitus (GDM, P=0.589), preeclampsia (P=0.942), premature rupture of membrane (PROM, P=0.276), scarred uterus (P=0.493) and postpartum hemorrhage (P=0.424). The cesarean section rate was 84.2%, 90.0% and 63.6% in three groups (P=0.208). However, neuraxial anesthesia was performed in 82.5% of cases in mild PAH and 90.0% of cases in moderate PAH, while 27.3% of cases of severe PAH underwent neuraxial anesthesia (P<0.001). The fetal outcome was similar in there groups.But the rate of admission of NICU was significantly different in three groups (P=0.011). Conclusions: Maternal and neonatal outcomes was similar in different severity of pulmonary hypertension.But the severity of pulmonary hypertension affect the type of anesthesia.Close monitoring during pregnancy and timely termination of pregnancy can improve the outcome of pregnancy.

Laparoscopic subtotal hysterectomy due to giant uterine fibroids: a case report.

The laparoscopic subtotal hysterectomy (LSH) was given to a patient whose uterus was about seven-month pregnanacy because of fibroids. The biggest problem was the operation space and visual field was too narrow. Different from the usual procedure we do, we morcellated the uterus at the beginning to expand the space. Loop ligature of the uterine isthmus was adopted to block uterine ateries before morcellating the uterus. After the adnexa exposed totally, we started to cut off the round ligaments, proper ligaments and fallopian tubes like usual. It was the first time we did LSH for so giant uterus in our hospital, although which was usually suitable for the uterus smaller than four-month pregnancy. But if the uterine ateries can be blocked effectively at the beginning, the uterus can be morcellated and the space will be enlarged. The laparoscopic subtotal hysterectomy will also be completed successfully.

[Adiponectin exerts antiproliferative effect on high glucose-induced BeWo cell proliferation in vitro].

OBJECTIVE: To determine the effects of adiponectin on high glucose induced BeWo cell proliferation in vitro. METHODS: BeWo cells were seeded in 96-well plates at the appropriate density. After treatments with high glucose (25 mmol/L), western blot analysis of cyclin D1 and a colorimetric assay (cell counting kit-8, CCK-8) were used to analyse BeWo cells' proliferation, and western blot was used to detect the expression of adiponectin. Moreover, we added adiponectin (20 µg/ml) in the culture medium and three methods were utilized for cell proliferation analysis: CCK-8, cell cycle analysis (by flow cytometry) and proliferating cell nuclear antigen (PCNA) immunocytochemical staining. RESULTS: Compared to BeWo cells cultured by normal glucose and high mannitol, the proliferation of BeWo cells treated by high glucose increased (P<0.05). Compared with BeWo cells cultured by high mannitol, the expression of adiponectin in BeWo cells treated by high glucose decreased. After added adiponectin in the culture medium, the proliferation of BeWo cells treated by adiponectin+high glucose decreased than that of cells treated by high glucose (0.770±0.050 versus 0.990±0.070, P<0.05); the proportion of G2+S phases of BeWo cells treated by adiponectin+high glucose decreased than that of cells treated by high glucose [(40.7±2.1)% versus (44.9± 3.9)%, P<0.05]; the rate of PCNA positive cell in BeWo cells treated by adiponectin+high glucose decreased than that of cells treated by high glucose [(28±5)% versus (44±5)%, P<0.05]. CONCLUSION: Adiponectin could inhibit proliferation of high glucose induced BeWo cells in vitro.

Genome-wide survey and phylogenetic analysis on subunit sequences of eukaryotic DNA polymerase delta.

DNA polymerase d is not only the major replicative enzyme in eukaryotic chromosomal DNA synthesis but is also the primary polymerase for most DNA repair pathways. However, the subunit composition of polymerase d varies in different organisms. While polymerase d in many eukaryotic species has all 4 subunits (POLD1, 2, 3, and 4), many other organisms do not possess POLD4. Whether POLD4 is indispensable and why these differences exist are unknown. In the present study, we identified the POLD4 protein sequences of 218 eukaryotic species and determined the POLD1, 2, and 3 protein sequences of 55 species representing various taxonomic groups. No insect and nematode species examined possessed POLD4. Approximately 80% of protozoan species did not contain POLD4. Nearly 50% of fungal species did not contain POLD4. Other animal and plant species are expected to contain POLD4. Phylogenetic analyses of POLD1, 2, 3, and 4 sequences revealed that most animal and plant species inherited DNA polymerase d from protozoa, whereas some other animal and plant species may have inherited polymerase d directly from fungi. Because a large number of protozoan and fungal species do not possess POLD4, current insect and nematode species lacking POLD4 may have evolved from ancestor protozoan species lacking POLD4; thus, other protozoan and animal species lacking POLD4 may share a similar evolutionary history. Future studies should examine the origin and indispensability of POLD4 in various organisms.

IL-10 treatment is associated with prohibitin expression in the Crohn's disease intestinal fibrosis mouse model.

Prohibitin, which can inhibit oxidative stress and mitochondrial dysfunction, has been shown to have significant anti-inflammatory activities. Here, we investigate the effects of altering prohibitin levels in affected tissues in the interleukin-10 knockout (IL-10KO) mouse model with intestinal fibrosis. The aim of this study is to investigate the effects of IL-10 on prohibitin and the role of prohibitin in intestinal fibrosis of murine colitis. After the mice were treated with IL-10, prohibitin expression and localization were evaluated in IL-10KO and wild-type (WT, 129/SvEv) mice. The colon tissue was then investigated and the potential pathogenic molecular mechanisms were further studied. Fluorescence-based quantitative polymerase chain reaction (FQ-PCR) and immunohistochemistry assays revealed a significant upregulation of prohibitin with IL-10 treatment. Furthermore, IL-10 decreases inflammatory cytokines and TGF-ß1 in the IL-10KO model of Crohn's disease and demonstrates a promising trend in decreasing tissue fibrosis. In conclusion, we hypothesize that IL-10 treatment is associated with increased prohibitin and would decrease inflammation and fibrosis in an animal model of Crohn's disease. Interestingly, prohibitin may be a potential target for intestinal fibrosis associated with inflammatory bowel disease (IBD).

Predictive potential of microsatellite markers on heterosis of fecundity in crossbred sheep.

Small Tail Han (STH) sheep is a famous Chinese local breed and has perfect prolificacy performance, but it is inferior to imported mutton sheep breeds on meat production. In this study, six imported male sheep populations (White Suffolk, Black Suffolk, Texel, Dorper, South African Mutton Merino and East Friesian) were crossbred with STH female sheep respectively. The heterosis values of litter size, average daily gain (ADG) and feed conversion ratio (FCR) of crossbred sheep were analyzed for seeking the optimal cross. Meanwhile 28 microsatellite markers were used to measure the genetic distance between imported populations and STH population. Regression between the genetic distance and heterosis was analyzed for evaluating potential of microsatellite on predicting heterosis. Results showed a significant positive linear correlation (r = 0.892, P < 0.05) between heterosis of litter size and genetic distance D (A) of six crosses. This implied that these microsatellite markers had moderate potential to forecast heterosis of litter size in sheep. Results of this study also indicated that South African Mutton Merino and East Friesian sheep would be the optimal sire breeds for the litter size and might bring the greatest economic benefit in six imported populations; Suffolk sheep could be prior consideration as sire breeds when breeding objective focused on ADG. Finally these results provided valuable information for Chinese sheep industry.

Genetic differentiation of chinese indigenous meat goats ascertained using microsatellite information.

To investigate the genetic diversity of seven Chinese indigenous meat goat breeds (Tibet goat, Guizhou white goat, Shannan white goat, Yichang white goat, Matou goat, Changjiangsanjiaozhou white goat and Anhui white goat), explain their genetic relationship and assess their integrity and degree of admixture, 302 individuals from these breeds and 42 Boer goats introduced from Africa as reference samples were genotyped for 11 microsatellite markers. Results indicated that the genetic diversity of Chinese indigenous meat goats was rich. The mean heterozygosity and the mean allelic richness (AR) for the 8 goat breeds varied from 0.697 to 0.738 and 6.21 to 7.35, respectively. Structure analysis showed that Tibet goat breed was genetically distinct and was the first to separate and the other Chinese goats were then divided into two sub-clusters: Shannan white goat and Yichang white goat in one cluster; and Guizhou white goat, Matou goat, Changjiangsanjiaozhou white goat and Anhui white goat in the other cluster. This grouping pattern was further supported by clustering analysis and Principal component analysis. These results may provide a scientific basis for the characteristization, conservation and utilization of Chinese meat goats.

[Application effects of feedforward control theory in the rollover bed treatment of mass patients with burn-explosion combined injury].

Objective: To explore the application effects of feedforward control theory in the rollover bed treatment of mass patients with burn-explosion combined injury. Methods: A retrospective observational research was conducted. From June 13 to 14, 2020, 15 patients with severe burn-explosion combined injury caused by liquefied natural gas tank car explosion and conforming to the inclusion criteria were admitted to the Second Affiliated Hospital of Zhejiang University School of Medicine. There were 13 males and 2 females, aged 33-92 (66±17) years. All the patients were treated with rollover bed from 48 h post admission, and the feedforward control theory was introduced, including establishing a special feedforward control management team for rollover bed, clarifying the duties of the medical staff in the rollover bed treatment of patients, implementing the cooperation strategy of multidisciplinary physician, training and examining for 80 nurses in the temporarily organized nurse team in the form of "rollover bed workshop", and formulating the checklist and valuation list of rollover bed treatment for continuous quality control. The frequency and the total number of turning over, and successful rate of one-time posture change with the rollover bed of patients within 30 days of admission were recorded, the occurrences of adverse events caused by improper operation for the rollover bed during the treatment were observed, including respiratory and cardiac arrests, treatment interruption, unplanned extubation, bed falling, and skin graft displacement. The lowest levels of arterial partial pressure of oxygen (PaO2) and arterial partial pressure of carbon dioxide (PaCO2), the number of patients with oxygenation index>300 mmHg (1 mmHg=0.133 kPa), and the occurrence of acute respiratory distress syndrome (ARDS) of patients within 2 days of admission and on the 30th day of admission were recorded. Results: Within 30 days of admission, the patients were turned over with the rollover bed for 2 to 6 times each day, with a total of 1 320 turning over operations, the successful rate of one-time posture change reached 99.9% (1 319/1 320), and no adverse event occurred. Within 2 days of admission, the lowest levels of PaO2 and PaCO2 of the patients were (100±19) and (42±4) mmHg, respectively, and the number of patients with mild, moderate, and severe ARDS were 10, 2, and 3, respectively, and none of the patients had oxygenation index>300 mmHg. On the 30th day of admission, the lowest levels of PaO2 and PaCO2 of the patients were (135±28) and (37±8) mmHg, respectively, 3 patients developed moderate ARDS, 1 patient developed severe ARDS, and 11 patients had oxygenation index>300 mmHg. Conclusions: The introduction of feedforward control theory in the treatment of rollover bed of mass patients with burn-explosion combined injury can ensure safe and successful completion of turning over with the rollover bed, promote the repair of burn wound, and improve respiratory function, and therefore improve the treatment quality of patients.

Polymorphisms of caprine GDF9 gene and their association with litter size in Jining Grey goats.

The exons 1, 2 and flanking region of growth differentiation factor 9 (GDF9) gene in five randomly selected does of Jining Grey, Boer and Liaoning Cashmere goats were amplified and analyzed. Thirteen nucleotide differences were identified in GDF9 gene between sheep (AF078545) and goats. Four SNPs (G3288A in intron 1, G423A, A959C [Gln320Pro] and G1189A [Val397Ile] in exon 2) were detected in four goat breeds with different prolificacy, in which G3288A was a new SNP in goats. The results showed that loci 3288, 423 and 1189 in Boer goats, loci 3288 and 423 in Guizhou White goats, loci 423 and 1189 in Liaoning Cashmere goats were all in complete linkage disequilibrium (D' = 1, r (2) = 1), respectively. In moderate (Boer goat) and low prolificacy (Liaoning Cashmere goat) breeds, linkage analysis indicated that there were more fervent linkage disequilibrium among loci 3288, 423 and 1189 than high prolificacy (Jining Grey and Guizhou White goats) breeds. For the 959 locus, the genotype distribution showed obvious difference between high prolificacy breeds and moderate or low prolificacy breeds (P < 0.05 or P < 0.01). The Jining Grey goat does with genotype CC or AC had 0.81 (P < 0.01) or 0.63 (P < 0.01) kids more than those with genotype AA, respectively. The present study preliminarily showed an association between allele C at 959 locus of GDF9 gene and high litter size in Jining Grey goats. These results provide further evidence that the GDF9 gene may be significantly correlated with high prolificacy in goats.

Enhancement of the hydrolysis activity of ß-galactosidase from Geobacillus stearothermophilus by saturation mutagenesis.

Thermostable ß-galactosidase (BgaB) from Geobacillus stearothermophilus is characterized by its thermoactivity in the hydrolysis of lactose to produce lactose-free milk products. However, BgaB has limited activity toward lactose. We established a method for screening evolved mutants with high hydrolysis activity based on prediction of substrate binding sites. Seven amino acid residues were identified as candidates for substrate binding to galactose. To study the hydrolysis activity of these residues, we constructed mutants by site-saturation mutagenesis of these residue sites, and each variant was screened for its hydrolysis activity. The first round of mutagenesis showed that changes in amino acid residues of Arg109, Tyr272, and Glu351 resulted in altered hydrolysis activity, including greater activity toward ortho-nitrophenyl-ß-d-galactopyranoside (oNPG). The mutants R109V and R109L displayed changes in the optimum pH from 7.0 to 6.5, and the mutant R109V/L displayed different substrate affinity and catalytic efficiency (k(cat)/K(m)). Mutant R109G showed complete loss of BgaB enzymatic activity, suggesting that Arg109 plays a significant role in maintaining hydrolysis activity. The optimum pH of mutant E351R increased from 7.0 to 7.5 and this mutant showed a prominent increase in catalytic efficiency with oNPG and lactose as substrates.

[Establishment of a predictive model for acute respiratory distress syndrome and analysis of its predictive value in critical burn patients].

Objective: To establish a predictive model for acute respiratory distress syndrome (ARDS) in critical burn patients with the screened independent risk factors, and to validate its predictive value. Methods: Totally 131 critical burn patients (101 males and 30 females, aged 18-84 years) who met the inclusion criteria were admitted to the Department of Burns of the Second Affiliated Hospital of Zhejiang University School of Medicine from January 2018 to December 2019. A retrospective case-control study was conducted. The patients were divided into ARDS group (54 cases) and non-ARDS group (77 cases) according to whether ARDS occurred or not. The statistics of patients in the two groups were recorded including the gender, age, burn index, combination of inhalation injury, smoking history, delayed resuscitation, indwelling nasogastric tube, and complication of sepsis, and the data were statistically analyzed with independent sample t test, chi-square test, and Fisher's exact probability test. The multivariate logistic regression analysis was performed on the indicators with statistically significant differences between the two groups to screen the independent risk factors for developing ARDS in critical burn patients, and the corresponding nomograph prediction model for the risk of ARDS in critical burn patients was established. The risk scores for patients developing ARDS were therefore obtained based on the above-mentioned nomograph, and the corresponding receiver operating characteristic (ROC) curve was drawn to calculate the area under the curve. The internal validation of the above-mentioned ARDS prediction model was performed using the Bootstrap method, and the area under the ROC curve was calculated for modeling group (79 cases) and validation group (52 cases), respectively. A calibration curve was drawn to assess the predictive conformity of the above-mentioned ARDS prediction model for the occurrence of ARDS in critical burn patients. Results: The burn index, proportion of combination of inhalation injury, and proportion of complication of sepsis of patients were significantly higher in ARDS group than in non-ARDS group (t=0.36, χ2=33.78, 49.92, P<0.01). The gender, age, smoking history, delayed resuscitation, and indwelling nasogastric tube of patients in ARDS group were close to those in non-ARDS group (P>0.05). The multivariate logistic regression analysis showed that the burn index, combination of inhalation injury, and complication of sepsis were the independent risk factors for developing ARDS in critical burn patients (odds ratio=1.05, 15.33, 5.02, 95% confidence interval=1.01-1.10, 2.65-88.42, 1.28-19.71, P<0.05 or P<0.01). The overall area under the ROC curve of the above-mentioned ARDS prediction model was 0.92 (95% confidence interval=0.88-0.97), and the area under the ROC curve was 0.95 and 0.91 (95% confidence interval=0.90-1.00, 0.86-0.97) for validation group and modeling group, respectively. When applying the above-mentioned ARDS prediction model for ARDS incidence prediction, there might be some risk of overestimating ARDS incidence when the prediction probability was <35.0% or >85.0%, and some risk of underestimating ARDS incidence when the prediction probability was 35.0%-85.0%. Conclusions: The burn index, inhalation injury, and sepsis are the independent risk factors for the occurrence of ARDS in critical burn patients. The risk prediction model for ARDS based on these three indicators has good predictive ability for ARDS in critical burn patients.