[Global trends in the incidence and prevalence of pneumoconiosis in 204 countries/territories from 1990 to 2019]

Objective: To analyze the changing trend of incidence and prevalence of pneumoconiosis globally, and provide scientific basis for the formulation of health policy. Methods: In June 2022, through the Global Health Data exchange (GHDx) query tool (http: //ghdx.healthdata.org/gbd-results-tool) , the pneumoconiosis incidence and prevalence data was downloaded and organized. Estimated annual percentage change (EAPC) and age-standardized rate (ASR) were used to estimate the trends of pneumoconiosis from 1990 to 2019. EAPC was estimated by linear regression model based on ASR. Results: The overall ASR of the incidence and prevalence of pneumoconiosis decreased from 1990 to 2019, and their EAPCs were-0.85% (95%CI: -1.11%--0.60%) and -0.78% (95%CI: -1.08%--0.49%) . Over the past 30 years, the incidence and prevalence of pneumoconiosis in all SDI areas showed decreasing trends, especially in high SDI areas, their EAPCs were -1.46% (95%CI: -1.76%--1.15%) and -1.99% (95%CI: -2.44%--1.53%) . 110 countries/areas showed increasing trends in age standardized incidence rate (ASIR) , with Iran and Georgia showing the most pronounced upward trend, their EAPCs were 5.32% (95%CI: 4.43%-6.22%) and 4.39% (95%CI: 3.81%-4.97%) . 125 countries/areas showed anincreasing trends in prevalence ASR, with Iran had the fastest rise in prevalence (EAPC=6.40%, 95%CI: 5.33%-7.49%) . Conclusion: Although decreasing trends in the burden of pneumoconiosis are observed globally from 1990 to 2019, but the burden of pneumoconiosis in low-and middle-income countries or regions are still heavy. We need more effective strategies to prevent and reduce the burden of pneumoconiosis.

[Preliminary experience with double-tract reconstruction combined with π-shaped esophagojejunal anastomosis after total laparoscopic proximal gastrectomy for the treatment of adenocarcinoma of esophagogastric junction]

Objective: To explore the feasibility and preliminary technical experience of the double-tract reconstruction combined with π-shaped esophagojejunal anastomosis after total laparoscopic proximal gastrectomy (TLPG) in the treatment of adenocarcinoma of esophagogastric junction (AEG). Methods: A descriptive case series study method was used. Clinical data of 12 AEG patients who underwent the double-tract reconstruction combined with π-shaped esophagojejunal anastomosis after TLPG from January 2021 to June 2021 at the Department of General Surgery, First Medical Center, PLA General Hospital were retrospectively analyzed. Among the 12 patients, the median tumor diameter was 2.0 (1.5-2.9) cm, and the pathological stage was T1-3N0-3aM0. All the patients routinely underwent TLPG and D2 lymph node dissection with double-tract reconstruction combined with π-shaped esophagojejunal anastomosis: (1) Double-tract reconstruction combined with π-shaped esophagojejunal anastomosis: mesentery 25 cm away from the Trevor ligament was treated, and an incision of about 1 cm was made on the mesenteric border of the intestinal wall and the right wall of the esophagus, two arms of the linear cutting closure were inserted, and esophagojejunal side-to-side anastomosis was performed. A linear stapler was used to cut off the lower edge of the anastomosis and close the common opening to complete the esophagojejunal π-shaped anastomosis. (2) Side-to-side gastrojejunostomy anastomosis: an incision of about 1 cm was made at the jejunum to mesenteric border and at the greater curvature of the remnant stomach 15 cm from the esophagojejunostomy, and a linear stapler was inserted to complete the gastrojejunostomy side-to-side anastomosis. (3) Side-to-side jejunojejunal anastomosis: an incision of about 1 cm was made at the proximal and distal jejunum to the mesangial border 40 cm from the esophagojejunostomy, and two arms of the linear stapler were inserted respectively to complete the side-to-side jejunojejunal anastomosis. A midline incision about 4-6 cm in the upper abdomen was conducted to take out the specimen, and an abdominal drainage tube was placed, then layer-by-layer abdominal closure was performed.

INDICATIONS

(1) adenocarcinoma of esophagogastric junction (Seiwert type II-III) was diagnosed by endoscopy and pathological examination; (2) ability to preserve at least 1/2 of the distal stomach after R0 resection of proximal stomach was evaluated preoperatively.

CONTRAINDICATIONS

(1) evaluation indicated distant metastasis of tumor or invasion of other organs; (2) short abdominal esophagus or existence of diaphragmatic hiatal hernia was assessed during the operation; (3) mesentery was too short or the tension was too high; (4) existence of severe comorbidities before surgery; (5) only palliative surgery was required in preoperative evaluation; (6) poor nutritional status.

MAIN OUTCOME MEASURES

operation time, intraoperative blood loss, postoperative complications, time to first flatus and time to start liquid diet, postoperative hospital stay, operation cost, etc. Continuous variables that conformed to normal distribution were presented as mean ± standard deviation, and those that did not conform to normal distribution were presented as median (Q1,Q3). Results: All the patients successfully completed TLPG with double-tract reconstruction combined with π-shaped esophagojejunal anastomosis, and postoperative pathology showed that no cancer cells were found on the upper incision margin. The operation time was (247.9±62.4) minutes, the median intraoperative blood loss was 100.0 (62.5, 100.0) ml, no intraoperative blood transfusion was required, the incision length was (4.9±1.0) cm, and the operation cost was (55.5±0.7) thousand yuan. The median time to start liquid diet was 1.0 (1.0, 2.0) days, and the mean time to flatus was (3.1±0.9) days. All the patients were discharged uneventfully. Only 1 patient developed postoperative paralytic ileus and infectious pneumonia with Clavien-Dindo classification of grade II. The patient recovered after conservative treatment. There was no surgery-related death. The postoperative hospital stay was (8.3±2.1) days. Conclusion: The double-tract reconstruction combined with π-shaped esophagojejunal anastomosis after TLPG is safe and feasible, which can minimize surgical trauma and accelerate postoperative recovery.

[A comparative study on short-term outcomes and quality of life for gastric cancer patients between totally laparoscopic total gastrectomy using an endoscopic linear stapler and laparoscopic-assisted total gastrectomy using a circular stapler]

Objective: To explore the differences of short-term outcomes and quality of life (QoL) for gastric cancer patients between totally laparoscopic total gastrectomy using an endoscopic linear stapler and laparoscopic-assisted total gastrectomy using a circular stapler. Methods: A retrospective cohort study was conducted. Clinicopathological data of patients with stage I to III gastric adenocarcinoma who underwent laparoscopic total gastrectomy from January 2017 to January 2020 were retrospectively collected. Those who were ≥80 years old, had serious complications that could affect the quality of life, underwent multi-organ resections, palliative surgery, emergency surgery due to gastrointestinal perforation, obstruction, bleeding, died or lost to follow-up within 1 year after surgery were excluded. A total of 130 patients were enrolled and divided into circular stapler group (CS group, 77 cases) and linear stapler group (LS group, 53 cases) according to the surgical method. The differences of age, gender, body mass index, number of comorbidities, history of abdominal surgery, ASA, tumor location, degree of differentiation, tumor length, tumor T stage, tumor N stage, tumor pathological stage and preoperative quality of life between the two groups were not statistically significant (all P>0.05). The observation indicators: (1) Surgery and postoperative conditions. (2) Postoperative complications: Any adverse conditions that require conservative treatment or surgical intervention after surgery were defined as postoperative complications, of which, complications occurring within 30 days after surgery were defined as early complications; complications occurring within 30 days to 1 year after surgery were defined as late complications. (3) Postoperative quality of life was assessed by the quality of life core scale (QLQ-C30) and gastric cancer specific module scale (QLQ-STO22). The higher the scores of functional scales and global health status, the better the corresponding quality of life. The higher the scores of symptoms scales, the worse the corresponding quality of life. Results: (1) Surgery and postoperative conditions: Compared with the CS group, the LS group presented less intraoperative blood loss [50.0 (50.0-100.0) ml vs. 100.0 (100.0-100.0) ml, Z=-3.111, P=0.002] and earlier time to flatus [(3.1±0.8) days vs. (3.5±1.1) days, t=-2.490, P=0.014]. However, there were no statistically significant differences between two groups of patients in terms of operation time, time to start a liquid diet and postoperative hospital stay (all P>0.05). (2) Postoperative complications: The early complication rates of the CS group and the LS group were 22.1% (17/77) and 18.9% (10/53), respectively, while the late complication rate were 18.2% (14/77) and 15.1% (8/53), respectively, whose differences were not statistically significant (all P>0.05). (3) Postoperative quality of life: After 1-year follow-up, 7 (5.4%) patients were lost, including 5 in CS group and 2 in LS group. One year after operation, the QLQ-C30 scale showed that the score of financial difficulty of the LS group was significantly higher than that of the CS group [33.3 (0 to 33.3) vs.0 (0 to 33.3), Z=-1.972, P=0.049] with statistically significant difference, and there were no statistically significant differences in the scores of other functional fields and symptom fields between the two groups (all P>0.05). The QLQ-STO22 scale showed that the scores of dysphagia [0 (0 to 5.6) vs. 0 (0 to 11.1), Z=-2.094, P=0.036] and eating restriction were significantly lower [0 (0 to 4.2) vs. 0 (0 to 8.3), Z=-2.011, P=0.044] in patients of the LS group than those of the CS group. There were no significant differences in scores of other symptoms between two groups (all P>0.05). Conclusions: Compared with the circular stapler, the esophagojejunostomy with linear stapler for gastric cancer patients can reduce intraoperative blood loss, shorten the time to flatus after operation, alleviate the symptoms of dysphagia and eating restriction but increase the economic burden to a certain degree.

[Risk factors of postoperative complication after total gastrectomy in advanced gastric cancer patients receiving neoadjuvant chemotherapy]

Objective: At present, there are few studies focusing on the factors short-term complications after total gastrectomy in patients with advanced gastric cancer receiving neoadjuvant chemotherapy (NACT). The purpose of this study is to provide a reference for clinical prevention of complications in these patients. Methods: A retrospective case-control study was conducted. Case inclusion criteria: (1) clinical stage II-III gastric cancer diagnosed by preoperative gastroscopy, pathology, abdominal CT, EUS or PET-CT; (2) evaluated suitable for NACT by MDT discussion; (3) no previous history of other malignant tumors and no concurrent tumor; (4) undergoing total gastrectomy+ D2 lymphadenectomy after NACT. Exclusion criteria: (1) age <18 or >80 years old; (2) severe concurrent diseases, and ASA classification>grade III; (3) stump gastric cancer or history of gastric surgery; (4) incomplete clinicopathological data. According to the above criteria, clinicopathological data of 140 advanced gastric cancer patients who underwent total gastrectomy after NACT in Chinese PLA General Hospital between June 2012 and June 2019 were collected, including 109 males and 31 females with mean age of (56.9±11.4) years and body mass indey (BMI) of (23.3±3.1) kg/m(2). Logistic analysis was used to analyze the relationship between postoperative complication and clinicopathological data. Factors in univariate analysis with P<0.05 were included in the multivariate analysis. Results: Postoperative complications (Clavien-Dindo classification ≥ II) occurred in 35 cases (25.0%) and severe complications (Clavien-Dindo classification ≥ IIIa) occurred in 4 cases (2.9%), including 1 case of esophago-jejunal anastomotic leakage, 1 case of vena cava thrombosis, 1 case of pleural effusion, 1 case of septic shock during perioperative days resulting in death. Univariate analysis showed that BMI (P=0.011), cycle of NACT (P=0.027), tumor diameter (P=0.021), and vascular invasion (P=0.033) were associated with postoperative complication within 30 days, while open/laparoscopic total gastrectomy were not associated with postoperative complication (P=0.926). Multivariate analysis revealed that BMI ≥ 25 kg/m(2) (OR=3.294, 95% CI: 1.343-8.079, P=0.009) and < 4 cycles of NACT (OR=2.922, 95% CI: 1.217-7.016, P=0.016) were independent risk factors for postoperative complication. The 3-year overall survival rates of patients with or without complication were 54.4% and 64.0%, respectively (P=0.395), and 3-year disease-free survival rates were 47.4% and 52.9%, respectively (P=0.587). Conclusions: Higher BMI and fewer cycles of NACT are independent risk factors of postoperative complication in advanced gastric cancer patients undergoing total gastrectomy after NACT. No obvious association is found between postoperative complication and surgical approaches.

[Analysis of clinicopathologic characteristics of gastric cancer patients undergoing gastrectomy based on a single-center gastric cancer database with above 10 000 cases]

Objective: The storage of medical data has been digitized in China, but a unified and structured model has not yet been established. The standardized collection, analysis and sorting of tumor clinical data is the foundation of improving the standard of tumor diagnosis and treatment. Therefore, establishing a database platform of gastric cancer (GC) is an urgent need to integrate data resources and improve the level of diagnosis and treatment. The population economics indexes of GC patients in the last 20 years are analyzed in a single-center GC database. The medical records were structured by natural language processing technology. Authors aim to investigate the clinical pathological characteristics, staging and survival of the GC patients with gastrectomy. Method: A retrospective cohort study was carried out. Clinicopatological data of patients receiving surgical treatment from 2000 to 2019 were retrospectively collected. According to the gastric cancer TNM staging guidelines from the Union for International Cancer Control and the American Joint Committee on Cancer (UICC/AJCC) 8th edition, the structured gastric cancer clinicopathological data were re-evaluated and interpreted. The Kaplan-Meier method and the log-rank test were used to compare survival rate among different groups of patients with complete follow-up data of 2010-2016. Results: Clinicopathological data of 13 492 GC patients were enrolled. The ratio of men to women in the whole group was 3.25:1.00, including 10 320 men with average onset age of 59.68 years, which was basically stable in recent 20 years, and 3172 women with average onset age of 55.93 years, which presented a trend of average increasement of 0.17 year per year. The average hospitalization duration for GC patients showed a decreasing trend year by year, which was 13.87 days in 2019. Average hospitalization cost for GC patients was increasing year by year, with a peak of 83 600 CNY in 2017 and 75 400 CNY in 2019. By natural language identification and exclusion criteria screening, a total of 7218 GC patients obtained structured clinicopathological information. Analysis on clinicopathological characteristics of 3626 GC patients in the last 5 years showed that the average diameter of tumor was (4.44±2.61) cm; the average number of harvested lymph node was 24.30±13.29; the proportion of surgical methods were as following: open surgery in 1398 cases (38.55%), laparoscopic surgery in 1856 cases (51.19%) and robotic surgery in 372 cases (10.26%). The postoperative pathological stage was as following: IA in 658 cases (18.15%), IB in 318 cases (8.77%), IIA in 559 cases (15.42%), IIB in 543 (14.98%), III A in 632 (17.43%), III B in 612 cases (16.88%), III C in 276 cases (7.61%), and IV in 28 cases (0.77%). Complete follow-up data of 3431 patients from 2010 to 2016 were presented. The 1-, 3- and 5-year survival rates were 82%, 69% and 60%, respectively for the whole group. The 1-, 3- and 5-year survival rates for patients undergoing laparoscopic surgery were 83%, 70% and 64%, respectively, and for those undergoing open surgery were 81%, 67% and 56%, respectively, and the difference between the two groups was not statistically significant (P=0.109). The 5-year survival rate of GC patients with different AJCC stages was as following: 88% in IA, 77% in IB, 70% in II A, 62% in II B, 44% in III A, 32% in III B, 22% in III C, and 17% in IV. Conclusion: This study provides basic data for the establishment of comprehensive diagnosis and treatment model of multicenter, shedding light on the improvement of comprehensive treatment of GC in China.

[Surgical selection and metastatic warning of splenic lymph node dissection in advanced gastric cancer radical surgery: a prospective, single-center, randomized controlled trial]

Objective: To investigate the surgical options for splenic lymph node dissection in patients with advanced gastric cancer undergoing radical total gastrectomy, and to evaluate the sentinel effect of No. 4s lymph node on splenic lymph node metastasis. Methods: A prospective, single-center, randomized and controlled study was carried out (Trial registration, No.NCT02980861). Enrollment criteria: (1) >18 years old and <65 years old; (2) gastric adenocarcinoma locating in the proximal or corpus; (3) preoperative clinical staging as cT2-4aN0-3M0; (4) D2 radical total gastrectomy feasible judged before operation; (5) physical ability score 0 to 1; (6) I to III of ASA classification. Pregnant or lactating women, patients with severe mental illness or previous history of upper abdominal surgery, those suffered from other malignant tumors in the past 5 years, or heart and lung system diseases judged to affect surgery before operation, those receiving preoperative chemotherapy, radiotherapy or targeted therapies, and distant metastases being found during surgery were excluded. According to above criteria, 222 patients at The First Medical Center of Chinese PLA General Hospital from December 2016 to December 2017 were enrolled prospectively and were randomly divided into the laparoscopic splenic hilar lymph node dissection group (laparoscopic group, n=114) and the open splenic hilar lymph node dissection group (open group, n=108). The result of rapid frozen immunohistochemistry of harvested No.4s lymph nodes was used to evaluate the sensitivity and specificity of sentinel effect on splenic hilar lymph node metastasis. The surgical parameters, postoperative recovery parameters, and complication rates were compared between the two groups. Results: There were 80 males and 34 females in the lapascopic group with a mean age of (56.1±10.2) years, and 69 males and 39 females in the open group with a mean age of (58.4±10.9) years. There were no significant differences in baseline data between the two groups (all P>0.05). Total blood loss was less in the laparoscopic group [(96.3±82.4) ml vs. (116.6±101.9) ml, t=1.124, P<0.001], and the amount of bleeding from the splenic hilar lymph nodes dissected was also less than that in the open group [(25.3±17.8) ml vs. (59.5±36.4) ml, t=1.172, P<0.001]. However, the operation time, the time of splenic hilar lymph node, the number of lymph node dissected and number of splenic hilar lymph node dissected were not significantly different between the two groups (all P>0.05). As compared to the open group, the laparoscopic group had shorter time to the first flatus [(1.3±1.2) days vs. (1.6±1.5) days, t=1.665, P=0.021], shorter time to fluid diet [(4.6±1.4) days vs. (4.9 ± 1.6) days, t=1.436, P=0.007], shorter time to remove nasogastric tube [(3.9±2.6) days vs. (4.3±2.4) days, t=0.687, P<0.001] and shorter hospital stay [(10.3±6.6) days vs. (12.1±7.2) days, t=0.697, P<0.001]. Complication rate was 14.0% (16/114) and (12.0%) ((1)3/108) in the laparoscopic group and the open group, respectively, without significant difference (χ(2)=6.723, P=0.331). The sensitivity of the No. 4s lymph node for the prediction of splenic hilar lymph node metastasis reached 89.5%, and the specificity reached 99.6%. Conclusions: Laparoscopic technique is safe and feasible in the treatment of splenic hilar lymph node dissection in advanced gastric cancer. The No.4s lymph node examination has good sentinel effect on predicting the metastasis of splenic hilar lymph nodes.

[Retrospective clinical analysis of surgical treatment for gastric stump carcinoma]

OBJECTIVES

To investigate the clinical feature and surgical procedures of gastric stump carcinoma (GSC) and to identify the prognostic factors which influence survival rate of GSC patients.

METHODS

Clinical data of 167 patients who underwent R0 resection for gastric stump carcinoma at Chinese People's Liberation Army General Hospital between January 1990 and December 2012 was collected. There were 144 male and 23 female cases. The clinicopathological features of GSC patients were compared between those who underwent initial surgery for benign disease (GSC-B group, 78 cases) and for gastric cancer (GSC-M group, 89 cases). The analysis of therapeutic methods and survival time were also performed.t-test was used to compare the quantitative data between two groups. Pearson χ(2) test was used to compare the various clinicopathological characteristics between the two groups. Kaplan-Meier method was used to analyze the survival rate. Multivariate survival analysis was based on the Cox proportional hazard model.

RESULTS

Compared with GSC-M group, the interval time between initial gastrectomy and surgery in GSC-B group was longer ( (28.2±10.2) years vs. (10.8±1.0) years, t=15.902, P=0.001). There were 56 patients (71.8%) who received BillrothⅠ reconstruction in GSC-B group, and 49 patients (55.1%) who received BillrothⅡ reconstruction in GSC-M group, the difference of anastomosis method between the two groups was statistically significant (χ(2)=25.770, P=0.001). Compared with GSC-M group, the tumor of GSC-B group was usually located at the anastomotic site (χ(2)=6.975, P=0.031). The overall 1-, 3-, and 5-year survival rates of the 167 patients were 87%, 60%, and 41%. The 5-year survival rates for TNM stagesⅠ, Ⅱ, and Ⅲ were 65%, 43%, and 22%, respectively (P= 0.001). Multivariate analysis showed that small intestinal or esophageal infiltration (HR=1.957, 95%CI: 1.096 to 3.494, P=0.023), tumor location (HR=1.618, 95%CI: 1.104 to 2.372, P=0.014), and TNM stage (HR=2.307, 95%CI: 1.708 to 3.118, P=0.001) have independent effect on survival. The metastasis rates of perigastric lymph nodes, jejunum anastomosis and mesenteric lymph nodes were very high (56.3% and 65.2%, respectively).

CONCLUSIONS

The GSC appears earlier in patients with gastrectomy for malignant disease than those with benign disease. Appropriate curative resection including residual lymph node dissection is very important to improve the prognosis. Small intestinal or esophageal infiltration, tumor location, and TNM stage have independent effect on survival.

Development of FQ-PCR method to determine the level of ADD1 expression in fatty and lean pigs

To determine how adipocyte determination and differentiation factor 1 (ADD1), a gene involved in the determination of pork quality, is regulated in Laiwu and Large pigs, we used TaqMan fluorescence quantitative real-time polymerase chain reaction (FQ-PCR) to detect differential expression in the longissimus muscle of Laiwu (fatty) and Large White (lean) pigs. In this study, the ADD1 and GAPDH cDNA sequences were cloned using a T-A cloning assay, and the clone sequences were consistent with those deposited in GenBank. Thus, the target fragment was successfully recombined into the vector, and its integrity was maintained. The standard curve and regression equation were established through the optimized FQ-PCR protocol. The standard curve of porcine ADD1 and GAPDH cDNA was determined, and its linear range extension could reach seven orders of magnitudes. The results showed that this method was used to quantify ADD1 expression in the longissimus muscle of two breeds of pig, and was found to be accurate, sensitive, and convenient. These results provide information regarding porcine ADD1 mRNA expression and the mechanism of adipocyte differentiation, and this study could help in the effort to meet the demands of consumers interested in the maintenance of health and prevention of obesity. Furthermore, it could lead to new approaches in the prevention and clinical treatment of this disease.

Leucine-rich repeat-containing G-protein-coupled receptor 5 is associated with invasion, metastasis, and could be a potential therapeutic target in human gastric cancer

Background:

Leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5), which is identified as a novel intestinal stem cell marker, is overexpressed in various tumours. In this study, we explore Lgr5 expression in gastric carcinoma and analyse its role in invasion, metastasis, and prognosis in carcinoma.

Methods:

A combination of immunohistochemistry, western blotting, and quantitative reverse transcription–polymerase chain reaction were used to detect mRNA and protein expression levels of Lgr5 and matrix metalloproteinase 2 (MMP2). Small interfering RNA against Lgr5 was designed, synthesised, and transfected into AGS cells. The effects of Lgr5 siRNA on cell invasion were detected by transwell invasion chamber assay and wound healing assay.

Results:

Leucine-rich repeat-containing G-protein-coupled receptor 5 expression was significantly higher in gastric carcinomas than in normal mucosa. Leucine-rich repeat-containing G-protein-coupled receptor 5 expression positively correlated with the depth of invasion, lymph node metastasis, distance of metastasis, and MMP2 expression levels. Multivariate analysis showed that Lgr5 had an independent effect on survival, and that it positively correlated with MMP2. Leucine-rich repeat-containing G-protein-coupled receptor 5 siRNAs inhibited Lgr5 mRNA and protein expression. Transwell assays indicated that these siRNAs resulted in significantly fewer cells migrating through the polycarbonate membrane, and wound healing assay also indicated that siRNAs decreased the migration of cells. Inhibition of Lgr5 resulted in a significant decrease in MMP2 and β-catenin levels compared with those in controls.

Conclusions:

Leucine-rich repeat-containing G-protein-coupled receptor 5 was correlated with invasion and metastasis. Leucine-rich repeat-containing G-protein-coupled receptor 5 inhibition could serve as a novel therapeutic approach.

Association of polymorphisms in the promoter region of chicken prolactin with egg production

Chicken prolactin (PRL) is a physiological candidate gene for egg production. The objective of the current research was to investigate the association of polymorphisms in the chicken PRL promoter region with egg production. Genotyping of 177 individuals from White Leghorn, Yangshan, Taihe Silkies, White Rock, and Nongdahe breeds for 6 single nucleotide polymorphisms (C-2402T, C-2161G, T-2101G, C-2062G, T-2054A, and G-2040A) and 1 24-bp indel (insertion-deletion) at the site of -358 of the chicken PRL gene revealed large breed differences in allelic frequencies for all but the T-2101G and T-2054A polymorphisms. An F2 population produced from Nongdahe x Taihe Silkies chickens consisted of 374 hens, which were recorded for egg production traits and genotyped for the above 7 polymorphisms. Marker-trait association analysis indicated that the 24-bp indel was associated with egg production (P < 0.01) and that H3 (C C T C T G) was the most advantageous haplotype for egg production.

[Px gene of rice-field eels primed in situ labeling]

Peroxidase (Px) gene of rice-field eels (Monopterus albus) was successfully localized to the segments of two bivalents, 8q15-q26 and 11q32-q37 with digoxigenin labeled primed in situ labeling (PRINS) technique, which is utilized for localization of single copy gene of fish for the first time. Our results demonstrated the possibility of mapping genes in fish by the DNA probes of other species and PRINS technique.