[Impact of aortic root morphology on the implantation depth of aortic valve prosthesis during trans-catheter aortic valve replacement in patients with native bicuspid aortic valve stenosis]

Objective: To investigate the impact of aortic root morphology on the implantation depth of aortic valve prosthesis during trans-catheter aortic valve replacement (TAVR) in bicuspid aortic valve patients. Methods: Clinical data of 40 patients with native bicuspid aortic valve stenosis who underwent TAVR using the self-expandable prosthesis (the Venus A-valve) from 2014 to 2017 in Fuwai Hospital was retrospectively analyzed. The patients were divided into non-deep implantation group (implant depth ≤10 mm by instant angiogram after implantation,29 cases) and deep implantation group (implant depth> 10 mm by instant angiogram after implantation,11 cases).Pre-procedural aortic root characteristics (e.g. calcification, angle and dimensions) were assessed by CT. The impact of aortic root morphology on the implantation depth and clinical outcomes were also evaluated. Results: The age was (75.1±5.9) years with equal representation from the raphe-type and non-raphe type (52.5%(21/40) and 47.5%(19/40)).The bigger aorta angle ((56.5±4.5)° vs. (47.4±9.4)°, P=0.004),more frequent mild-calcification (HU850, <200 mm(3)) or severe-calcification(HU850, >1 000 mm(3)) of aortic leaflets (7/11 vs. 4/29, P=0.006), as well as higher ratio of left ventricular outflow tract perimeter to annulus perimeter ((109.2±7.5)% vs. (101.5±6.5)%, P=0.004) were found in the deep implantation group compared to the non-deep implantation group. The new in-hospital onset of bundle-branchheart-block or atrioventricular block conduction disturbance rate was higher in the deep implantation group than in the non-deep implantation group (6/11 vs. 2/29, P=0.030).Left ventricular ejection fraction was similar between deep implantation group and non-deep implantation group at baseline((49.9±8.9)% vs. (55.8±10.4)%, P=0.117), and was significantly lower in the deep implantation group than in the non-deep implantation group at 30 days after implantation ((51.6±12.8)% vs. (60.9±8.1)%, P=0.020). Conclusion: Aortic root morphology of bicuspid aortic valve patients is associated with implantation depth of the prosthesis during TAVR, which affects the conduction system and left ventricular function during and post TAVR.

[The influence of chemotherapy-induced leucopenia on the disease-free survival of gastric cancer patients after radical gastrectomy]

Objective: To investigate the association between chemotherapy-induced leucopenia and patients' disease-free survival in gastric cancer patients who received radical gastrectomy. Methods: The clinical data of 273 gastric cancer patients who received radical gastrectomy and postoperative adjuvant chemotherapy between January, 2010 and December, 2015 in PLA 309(th) hospital was reviewed retrospectively. Results: A total of 195 (71.4%) patients experienced at least one time of leucopenia, while it was absent in the other 78 (28.6%) patients. The median disease-free survival of patients with or without leucopenia was 49.7 and 44.0 months respectively (P=0.009), leucopenia was an independent factor influencing patients' disease-free survival (HR=2.758, P=0.022), but there was no statistical difference between the disease-free survival of patients with different degrees and frequency of leucopenia (P=0.446, 0.123). Conclusion: Chemotherapy-induced leucopenia is a predictor of good prognosis for gastric cancer patients who receive radical gastrectomy.

UV absorption spectrum of allene radical cations in solid argon

Electron bombardment during deposition of an Ar matrix containing a small proportion of allene generated allene cations. Further irradiation of the matrix sample at 385 nm destroyed the allene cations and formed propyne cations in solid Ar. Both cations were identified according to previously reported IR absorption bands. Using a similar technique, we recorded the ultraviolet absorption spectrum of allene cations in solid Ar. The vibrationally resolved progression recorded in the range of 266-237 nm with intervals of about 800 cm^-1 was assigned to the A²E ← X²E transition of allene cations, and the broad continuum absorption recorded in the region of 229-214 nm was assigned to their B²A₁ ← X²E transition. These assignments were made based on the observed photolytic behavior of the progressions and the vertical excitation energies and oscillator strengths calculated using time-dependent density functional theory.

[Salivary microbiome in people with obesity: a pilot study]

OBJECTIVE

To investigate the characterization of the salivary microbiome in people with obesity and the differences in microbial composition, gene function and metabolic pathways of salivary microbiome between people with obesity and normal weight controls.

METHODS

The study was carried out in people with obesity and age- and sex-matched normal weight controls. None of these selected participants had the systemic disease, oral mucosal disease or periodontal disease. Unstimulated saliva samples were collected and oral examination was conducted. DNAs from saliva samples were extracted and sequenced in an Illumina NextSeq 500 platform. Community composition, linear discriminant analysis of taxonomic differences,gene prediction, gene set construction and annotation of gene function were performed.

RESULTS

The classified bacterial reads of the samples were 2 630 428 for each sample. A total of 11 phyla, 19 classes, 26 orders, 41 families, 62 genera and 164 species were detected ultimately. All samples had the same predominant phyla (Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria and Fusobacteria). There were statistical differences between the groups at the class, order, family, genus and species levels. At the class level, Negativicutes and Erysipelotrichia were more abundant in the obesity group, while Flavobacteriia and Bateroidetes dominated in normal weight group (P<0.05). At the species level, 16 showed significant differences in relative abundance among the groups, in which Prevotella melaninogenica,Prevotella salivae,Solobacterium moorei and Atopobium parvulum ware more abundant in the obesity group, whereas Streptococcus sanguinis dominated in normal weight group (P<0.05). The people with obesity had a higher number of salivary microbial genes (P<0.05). We produced statistics on gene prediction and found salivary microbiome of obesity group had a higher number of genes (P < 0.05). Genes associated with the pathways of metabolism and environmental information processing and human diseases were significantly enriched in the saliva samples of people with obesity (P < 0.01).

CONCLUSION

Significant differences were seen in composition, gene function and metabolic pathways of salivary microbiome between people with obesity and normal weight people. We hope to go on further study with larger sample size in the near future.

[Effect of transcatheter aortic valve replacement using Venus-A valve for treating patients with severe aortic stenosis]

Objective: To evaluate the effect of transcatheter aortic valve replacement(TAVR) using Venus-A valve for treating patients with severe aortic stenosis. Methods: In this prospective study, 101 consecutive severe aortic stenosis patients with high surgical risk(Society of Thoracic Surgeon(STS) score ≥4%) or at prohibitive surgical risk were enrolled from 5 academic cardiovascular centers in China(Fuwai hospital, the second affiliated hospital of Zhejiang university school of medicine, West China hospital of Sichuan university, the first affiliated hospital of Nanjing medical university, Ruijin hospital of Shanghai Jiaotong university school of medicine) from September 2012 to January 2015, and Venus-A valves were used in TAVR for these patients. The primary endpoints were death from any cause and major stroke in 1 year. The secondary endpoints included efficacy and safety of TAVR in 1 year. Results: TAVR success rate was 97.9%(98/101), and 3 patients were transferred to receive surgical AVR. There were 85 patients using 1 Venus-A valve, and 13 patients underwent valve-in-valve implantation using 2 Venus-A valves. There were 1 case(1.0%) of stroke, 2 cases(2.0%)of acute myocardial infarction, 5 cases(5.0%) of pericardial effusion, 6 cases(5.9%) of severe vascular complication, and 2 cases(2.0%) of death after 7 days of TAVR. Meanwhile, aortic pressure gradient derived from echocardiography was significantly reduced when compared with pre-procedure level(11(8, 15) mmHg (1 mmHg=0.133 kPa) vs. 59(45, 71)mmHg, P<0.01), and there was no aortic root rupture or leaflets thrombosis. Rate of NYHA functional class ≤Ⅱ improvements were observed at 6 months follow-up when compared with pre-procedure(94.4%(84/89)vs. 21.3%(21/89), P<0.01). The primary endpoint was 7.9%(8/11), and the incidence of all cause death and stroke was 5.9%(6/101) and 2.0%(2/101) respectively at 1 year after the procedure. Kaplan-Meier survival analysis showed that cumulative survival rate was 94.1% at 1 year after the procedure. Conclusion: TAVR using Venus-A valve for treating patients with severe aortic stenosis is effective and safe in the early and medium term post procedure.

[Hereditary polycystic kidney disease: a neglected etiology of liver cirrhosis]

There are two common types of hereditary polycystic kidney diseases, autosomal dominant polycystic kidney disease and autosomal recessive polycystic kidney disease. Congenital hepatic fibrosis is an autosomal recessive disorder and can occur in hereditary polycystic kidney disease. Therefore, hereditary polycystic kidney disease is one of the causes of unexplained liver fibrosis and liver cirrhosis.

[Safety and feasibility of sheathless transfemoral aortic valve implantation]

Objective: To investigate the safety and feasibility of sheathless transfemoral aortic valve replacement (TAVR). Methods: In this prospective study, we enrolled 23 patients with severe aortic stenosis (AS) who were inoperable or at high-risk for surgical aortic valve replacement operation in Fuwai hospital From September 2012 to June 2015. Multislice spiral CT and angiography of femoral artery showed that all patients had minimal femoral artery diameters (<6.5 mm) and severe calcification which was not suitable for transfemoral TAVR through sheath. We attempted to apply the sheathless transfemoral TAVR using Venus-A prosthesis without sheath insertion, and procedure related complication during the procedure and hospital stay were observed. Results: The 6 mm×30 mm balloon was used for femoral artery predilation in 1 patient with iliofemoral artery stenosis before delivery system was transported. In the other 22 patients, the delivery system was transported directly. A total of 21 patients finished TAVR with transfemoral sheathless technique. In 2 patients, prosthesis was unable to fully expand after release due to severe valve calcification, and patients received urgent surgical aortic valve replacement. One patient had valve dislocation into the ascending aorta that was not related to the sheathless replacement technique, and delivery system and Venus-A valve were removed after femoral artery was opened surgically, and repeated sheathless TAVR implantation was performed and was successful. Moderate aortic regurgitation occurred in 2 patients immediately after procedure, and trace or mild aortic regurgitation was detected in rest of the patients. One patient had puncture site rupture and bleeding after procedure, and was successfully treated by balloon compression without blood transfusion. Complete atrioventricular block occurred in 3 patients within 24 hours after procedure and lasted after 48-72 hours, permanent pacemakers were implanted in these patients. Conclusion: The sheathless transfemoral technique in TAVR is safe and feasible in severe aortic stenosis patients with small access vessel diameter.

Direct infrared observation of hydrogen chloride anions in solid argon

To facilitate direct spectroscopic observation of hydrogen chloride anions (HCl^-), electron bombardment of CH₃Cl diluted in excess Ar during matrix deposition was used to generate this anion. Subsequent characterization were performed by IR spectroscopy and quantum chemical calculations. Moreover the band intensity of HCl^- decays slowly when the matrix sample is maintained in the dark for a prolonged time. High-level ab inito calculation suggested that HCl^- is only weakly bound. Atom-in-molecule charge analysis indicated that both atoms of HCl^- are negatively charged and the Cl atom is hypervalent.

[Effects and its mechanism of Nimotuzumab on radiosensitivity of esophageal carcinoma ECA-109 and TE-13 cell lines]

Objective: To investigate the effects of nimotuzumab on radiosensitivity of ECA-109 and TE-13 esophageal carcinoma cell lines and explore its possible mechanism. Methods: The ECA-109 and TE-13 cells were divided into control group, irradiation group, medicine group, and combined group (irradiation + medicine). In the combined group, ECA-109 and TE-13 cells were treated with nimotuzumab for 24 h before irradiation, and the cells were collected 2 h after irradiation. The radiosensitizing effects of nimotuzumab on ECA-109 and TE-13 cells were evaluated by clone formation assay. Cell apoptosis was detected by flow cytometry. Western blotting was used to evaluate the expression of EGFR, p-EGFR, DNA-PKcs, p-DNA-PKcs and γH2AX. Results: The values of D_q (quasithreshold dose), D₀(mean lethal dose)and SF₂ (surviving fraction at 2 Gy) of ECA-109 and TE-13 cells in the combined group were significantly lower than those of the radiation group (for ECA-109 cells, 1.11 vs. 1.72, 1.40 vs. 2.14, 0.42 vs. 0.66, respectively; for TE-13 cells, 0.41 vs. 0.46, 0.43 vs. 0.65, 0.40 vs. 0.71, respectively (all P<0.05). The sensitivity enhancement ratio (SER) of ECA-109 and TE-13 cells were 1.35 and 1.43, respectively. Flow cytometry showed that the apoptosis rate of ECA-109 and TE-13 cells in the combined group were significantly higher than those of the radiation group [for ECA-109 cells, (41.31±1.52)% vs. (9.54±0.52)%; for TE-13 cells, (46.28±0.28)% vs. (11.32±0.31)%, both P<0.01]. Western blotting showed that the expression levels of EGFR and DNA-PKcs were not significantly different in all groups (all P>0.05). Compared with those of the control group, p-EGFR and p-DNA-PKcs of the radiation group were significantly higher in both cell lines (P<0.05), and the γH2AX levels in the radiation group and medicine group were significantly higher than that of the control group (P<0.05). Compared with those of the radiation group and medicine group, p-EGFR and p-DNA-PKcs protein expression in the combined group were decreased significantly (P<0.05), while γH2AX protein expression was significantly increased (P<0.05). Conclusions: Nimotuzumab can enhance the radiosensitivity of esophageal cancer ECA-109 and TE-13 cells. The potential mechanism may be related to the inhibition of EGFR phosphorylation and down-regulation of DNA damage repair proteins. The radiosensitizing effect of nimotuzumab is greater on poorly differentiated esophageal cancer cells.

Identification of a Simplest Hypervalent Hydrogen Fluoride Anion in Solid Argon

Hypervalent molecules are one of the exceptions to the octet rule. Bonding in most hypervalent molecules is well rationalized by the Rundle–Pimentel model (three-center four-electron bond), and high ionic bonding between the ligands and the central atom is essential for stabilizing hypervalent molecules. Here, we produced one of the simplest hypervalent anions, HF⁻, which is known to deviate from the Rundle–Pimentel model, and identified its ro-vibrational features. High-level ab inito calculations reveal that its bond dissociation energy is comparable to that of dihalides, as supported by secondary photolysis experiments with irradiation at various wavelengths. The charge distribution analysis suggested that the F atom of HF⁻ is negative and hypervalent and the bonding is more covalent than ionic.

[Clinical application of cone-beam computed tomography in sialolithiasis diagnosis]

Diagnosis of sialolithiasis usually needs the combination of clinical and imaging-based examination. The use of cone-beam computed tomography (CBCT) in patients with sialolithiasis has been increasing in dental practice in recent years. CBCT has some advantages in the diagnosis and treatment of sialolithiasis. However, CBCT should not be considered as the first choice for the diagnosis and treatment of sialolithiasis, and it is suitable to be used in the case of complex sialolithiasis which can not be diagnosed by traditional imaging methods. The research progress of the use of CBCT in the diagnosis of sialolithiasis is reviewed.

[Outcome comparison of different therapy procedures in surgical high-risk elderly patients with severe aortic stenosis]

Objective: To compare the outcome of surgical high-risk elderly patients with severe aortic stenosis(SAS) treated by different therapy procedures, including transcatheter aortic valve implantation(TAVI), surgical aortic valve replacement(SAVR), and drug therapy. Methods: We retrospectively analyzed the clinical data of 242 surgical high-risk elderly (age ≥65 years old) SAS patients hospitalized in Fuwai Hospital between September 2012 and June 2015. According to the treatment method, patients were divided into TAVI group (81 cases), SAVR group (59 cases) and drug therapy group (102 cases). The primary end point was all-cause mortality at 1 year post procedure, and secondary end point included cardiac function class(NYHA), vascular complication, valvular function, non-fatal myocardial infarction, new atrial fibrillation, stroke, bleeding, pacemaker implantation, acute renal failure, and readmission. We used the Kaplan-Meier method to estimate survival function based on follow up data and survival was compared between groups with the use of the log-rank test. Results: (1) In the baseline data, there were statistically significant difference among 3 groups for the age, left ventricular ejection fraction, cardiac function class Ⅲ and Ⅳ, rates of combined diabetes, chronic renal failure, mild and moderate mitral regurgitation (P<0.01 or 0.05). The risk score of the Society of Thoracic Surgeons(STS) was 7.28±4.98 in the TAVI group, and 5.67±3.49 in the SAVR group(P=0.036). (2) The perioperative rates of pacemaker implantation(11.3%(9/81) vs. 0, P=0.025) and mild paravalvular regurgitation(29.6%(24/81) vs.1.7%(1/59), P<0.001) were significantly higher in TAVI group than in SAVR group.(3)The rate of rehospitalization was significantly lower in TAVI group than in SAVR group(3.0%(2/67) vs. 22.7%(10/44) P=0.005) and the rate of pacemaker implantation was significantly higher in TAVI group than in SAVR group(17.5 (12/67) vs. 0, P=0.008) after 1 year. The rates of death from any cause in the TAVI (5.8%(4/67)) and SAVR group (11.4%(5/44)) were significantly lower than that in the drug therapy group (54.9%(50/91), both P<0.05) after 1 year and was similar between TAVI group and SAVR group(P=0.622). (4) The rates of cardiac function classⅠandⅡ increased and Ⅲ and Ⅳ decreased in TAVI and SAVR group after 1 year when compared with base line(P<0.001). The rates of cardiac function class Ⅱ, and Ⅲ increased , class Ⅰ and Ⅳ decreased in drug therapy group after 1 year compared with base line (P=0.020). (5)The survival rates after 1 year were significantly higher in the TAVI group and SAVR group than in the drug therapy group(log-rank test, P<0.001), and the difference was similar between TAVI group and SAVR group (log-rank test, P=0.062). Conclusion: In surgical high-risk elderly patients with SAS, the prognosis of drug therapy was poor, and TAVI and SAVR were associated with similarly improved rates of survival after 1 year, although there were significant differences in periprocedural complications between TAVI and SAVR groups.

[The application of mandarin acceptable noise level and COS in hearing aid fitting for presbyacusis]

Objective:The purpose of this study was to inquiry into the application of mandarin acceptable noise level(M-ANL) and client oriented scale of improvement in evaluation of hearing aid fitting for presbyacusis. Method:Thirty-two adults with presbycusis who used the hearing aid for the first time were selected for the study. M-ANL tests were done prior to the hearing aid fitting. Six weeks later, these patients were asked to fill in questionnaire of client oriented scale of improvement (COSI).The subjects were divided into 3 groups according to the time of hearing aid using in their daily lives: less than one hour per day, 1 to 4 hours per day and more than 4 hours per day. The relativity of M-ANL and the score of COSI were compared. Result:①There were significant differences of the M-ANL among 3 groups(P<0.05); ②The scores of COSI of group 1(less than one hour per day) was lower than group 2(1 to 4 hours per day), while there were no significant differences between the scores of group 2(1 to 4 hours per day) and group 3(more than 4 hours per day); ③There was good correlation between the score of M-ANL and COSI. Conclusion:M-ANL can forecast the satisfaction of hearing aids fitting. And COSI can play an effective role in outcome measurement.

[Cosmetological thinking and methods in TCM in the Sui-Tang Dynasty]

In the heyday of Chinese feudal society, women's status in the society of the Sui-Tang period was improved in the Tang Dynasty.The demand for female to stay young and anti-aging had attracted lots of attention in the society, thus providing a favorable social environment for the formation and development of Chinese herbal cosmetology. The important representative medical works on traditional Chinese medicine (TCM) were published in the Sui and Tang Dynasties, such as Bei ji qian jin yao fang (Essential Recipes for Emergent Use Worth A Thousand Gold), Qian jin yi fang (Supplement to Recipes Worth A Thousand Gold), Wai tai mi yao (Arcane Essentials from the Imperial Library) etc., all carry chapter(s) on Chinese herbal cosmetology. In the Tang Dynasty, beauty techniques became perfect, with rich exquisite make-up style. Make-up had become an integral part of daily life. Cosmetic surgery has reached a fairly high level, with a number of cosmetic surgeries appeared, such as the making of artificial dimples, artificial eyes, and dental cosmetic.

Infrared spectra of ovalene (C32H14) and hydrogenated ovalene (C32H15˙) in solid para-hydrogen

We report the infrared (IR) spectra of ovalene (C₃₂H₁₄) and hydrogenated ovalene (C₃₂H₁₅˙) in solid para-hydrogen (p-H₂). The hydrogenated ovalene and protonated ovalene were generated from electron bombardment of a mixture of ovalene and p-H₂ during deposition of a matrix at 3.2 K. The features that decreased with time have been previously assigned to 7-C₃₂H₁₅⁺, the most stable isomer of protonated ovalene (Astrophys. J., 2016, 825, 96). The spectral features that increased with time are assigned to the most stable isomer of hydrogenated ovalene (7-C₃₂H₁₅˙) based on the expected chemistry and on a comparison with the vibrational wavenumbers and IR intensities predicted by the B3PW91/6-311++G(2d,2p) method. The mechanism of formation of 7-C₃₂H₁₅˙ is discussed according to the observed changes in intensity and calculated energetics of possible reactions of H + C₃₂H₁₄ and isomerization of C₃₂H₁₅˙. The formation of 7-C₃₂H₁₅˙ is dominated by the reaction H + C₃₂H₁₄ → 7-C₃₂H₁₅˙, implying that, regardless of the presence of a barrier, the hydrogenation of polycyclic aromatic hydrocarbons occurs even at 3.2 K.

Photochemistry and infrared spectrum of single-bridged diborane(5) anion isolated in solid argon

Three-center two-electron bonds are important for understanding electron-deficient molecules. To examine such a molecule, we produced a diborane(5) anion with a single-bridged structure upon electron bombardment during matrix deposition of Ar containing a small proportion of diborane(6). The diborane(5) anion was destroyed upon photolysis at 180, 220, 385, and 450 nm, but not at 532 nm. Moreover, the possible formation of neutral diborane(5) was observed upon photolysis at 385 and 450 nm, whereas neutral diborane(3) was observed upon photolysis at 180 and 220 nm. The observed line wavenumbers, relative intensities, and isotopic ratios of the diborane(5) anion agreed satisfactorily with those predicted by density functional theory calculations at the B3LYP/aug-cc-pVTZ level of theory. Thus, this method produced the boron hydride anion of interest with few other fragments, which enabled us to clearly identify the IR spectrum of the diborane(5) anion.

[Esophageal adenocarcinoma: the clinicopathologic features, patterns of lymph node metastasis and its influencing factors]

OBJECTIVE

To investigate the clinicopathological characteristics, patterns of lymph node metastasis and the influencing factors in esophageal adenocarcinoma.

METHODS

A total of 201 cases of esophageal adenocarcinoma were selected for this study, including 89 cases of pure adenocarcinoma, 57 cases of adenoacanthoma cell carcinoma, 33 cases of mucoepidermoid carcinoma and 22 cases of adenoid cystic carcinoma. A total of 2026 lymph nodes were dissected with an average of 10 lymph nodes. The rule of lymph node metastasis in patients with esophageal adenocarcinoma was analyzed, and the risk factors for lymph node metastasis were identified.

RESULTS

Esophageal adenocarcinoma in the middle thoracic esophagus accounted for 50.7% of all patients, and 43.8% in the lower thoracic esophagus. Ninety out of 201 cases (44.8%) had lymph node metastasis. 322 lymph nodes were positive for metastatic adenocarcioma with a metastatic ratio of 15.9% (322/2026). Among the patients with upper-thoracic esophageal carcinoma, 9.1% (1/11) of the cases had lymph node metastasis in the superior mediastinum but no lymph node metastasis was found in the middle mediastinum, lower mediastinal and abdominal lymph nodes. The middle-thoracic esophageal adenocarcinoma showed more extensive lymph node metastasis. Lower mediastinal and abdominal lymph node metastases were common in lower-thoracic esophageal cancer. Multivariate analysis showed that gender, length of lesion, depth of invasion and vascular invasion were independent risk factors for lymph node metastasis in esophageal adenocarcinoma (P=0.010, P=0.006, P=0.000, P=0.019, respectively). Male patients had more lymph node metastasis than female patients (49.1% vs 26.3%,P=0.011). The rates of lymph node metastasis in the tumor length ≤3 cm group, 3.1-5 cm group and >5 cm group were 20.4%, 42.9% and 65.7%, respectively. Lymphatic metastasis rates in the T1, T2, T3, T4 stage cancers were 7.1%, 36.8%, 38.1% and 69.4%, respectively, (P<0.001). Patients with vascular invasion had a higher rate of lymph node metastasis (73.9%) than the patients without vascular invasion (41.0%) (P=0.003).

CONCLUSIONS

Most of the esophageal adenocarcinoma are distributed in the middle thoracic esophagus, followed by that in the lower thoracic segment. The lymph node metastasis rate, lymph node metastasis ratio and pattern of lymph node metastasis are similar to those of esophageal squamous cell carcinoma. Male, tumor length, depth of invasion and vascular invasion are risk factors of lymph node metastasis for patients with esophageal adenocarcinoma.

Targeting exogenous GDNF gene to the bovine somatic cell beta-casein locus for the production of transgenic bovine animals

Considerable attention is currently being directed toward methods for producing recombinant human proteins in the mammary glands of genetically modified transgenic livestock. However, the expression of inserted genes in transgenic animals is variable and often very low because of the randomness of the site of transgene integration. One possible strategy to avoid the expression problem associated with random integration is to use site-specific integration by targeting integration to a high expression locus and, thereby, to improve expression of the transferred gene. In the present study, we focused on glial cell line-derived neurotrophic factor (GDNF), a novel type of neurotrophic factor first cloned in 1993. Research has shown that GDNF may have potential applications in the treatment of Parkinson's disease and other diseases of the central nervous system since it acts as a protective factor for central dopaminergic neurons. Here, we constructed a gene targeting vector to knock-in the human GDNF gene at the bovine beta-casein gene locus as a first step to producing transgenic animals with a high level of expression of human GDNF protein in their mammary glands. Bovine fetal fibroblast cells were transfected with linearized pNRTCNbG by electroporation. Three cell clones were identified with successful targeting to the beta-casein locus; and were confirmed using both polymerase chain reaction analysis and sequencing. Gene-targeted cells were used as nuclear donors; a total of 161 embryos were reconstructed, 23 of which developed to the blastocyst stage. These blastocysts were transferred to 8 recipient cows, but no offspring were obtained.