Realization of digital twin for dynamic control toward sample variation of ion exchange chromatography in antibody separation.

Digital twin (DT) is a virtual and digital representation of physical objects or processes. In this paper, this concept is applied to dynamic control of the collection window in the ion exchange chromatography (IEC) toward sample variations. A possible structure of a feedforward model-based control DT system was proposed. Initially, a precise IEC mechanistic model was established through experiments, model fitting, and validation. The average root mean square error (RMSE) of fitting and validation was 8.1% and 7.4%, respectively. Then a model-based gradient optimization was performed, resulting in a 70.0% yield with a remarkable 11.2% increase. Subsequently, the DT was established by systematically integrating the model, chromatography system, online high-performance liquid chromatography, and a server computer. The DT was validated under varying load conditions. The results demonstrated that the DT could offer an accurate control with acidic variants proportion and yield difference of less than 2% compared to the offline analysis. The embedding mechanistic model also showed a positive predictive performance with an average RMSE of 11.7% during the DT test under >10% sample variation. Practical scenario tests indicated that tightening the control target could further enhance the DT robustness, achieving over 98% success rate with an average yield of 72.7%. The results demonstrated that the constructed DT could accurately mimic real-world situations and perform an automated and flexible pooling in IEC. Additionally, a detailed methodology for applying DT was summarized.

Model-assisted process design for better evaluation and scaling up of continuous downstream bioprocessing.

Continuous process is a promising alternative for tradition batch process in biomanufacturing, which has higher productivity and lower material consumption. However, despite the maturation of necessary technologies for continuous process, there are few discussion about optimization of full continuous process. One possible reason is that the continuous process is such a complex and interacted process that the traditional experiment-based optimization approach is not sufficient anymore. To address that problem, the process simulation tool SuperPro Designer and continuous capture chromatography model were integrated into a model-assisted design platform for better development of continuous process. The influences of different continuous capture operation modes and sub-lot number under various upstream conditions were analyzed for pilot-scale production. The best combination of operation mode and sub-lot number were determined for the highest equipment utilization without any conflict. After the process optimization, the equipment utilization of continuous process was significantly improved to 27.3%. Then, a pilot-scale case study was carried out to validate the proposed approach. The results showed that the scaling up and process design of continuous process were successful. No time conflict and process failure happened and the final product met the release specification. Finally, the cost of goods was evaluated with SuperPro Designer, and the results showed a 17.4% cost reduction for optimized continuous downstream process compared to batch process, which is promoting for the future industrial applications.

Converting a mAb downstream process from batch to continuous using process modeling and process analytical technology.

The biopharmaceutical market is driving the revolution from traditional batch processes to continuous manufacturing for higher productivity and lower costs. In this work, a batch mAb downstream process has been converted into an integrated continuous process with the combination of multiple techniques. For process intensification, two batch mode unit operations (protein A capture chromatography, ultrafiltration/diafiltration) were converted into continuous ones; for continuity, surge tanks were used between adjacent steps, and level signals were used to trigger process start or stop, forming a holistic continuous process. For process automation, manual operations (e.g., pH and conductivity adjustment) were changed into automatic operation and load mass was controlled with process analytical technology (PAT). A model-based simulation was applied to estimate the loading conditions for the continuous capture process, resulting in 21% resin capacity utilization and 28% productivity improvement as compared to the batch process. Automatic load mass control of cation exchange chromatography (CEX) was achieved through a customized in-line protein quantity monitoring system, with a difference of less than 1.3% as compared to off-line analysis. Total process time was shortened from 4 days (batch process) to less than 24 hours using the continuous downstream process with the overall productivity of 23.8 g mAb per day for the bench-scale system. Comparable yield and quality data were obtained in three test runs, indicating a successful conversion from a batch process to a continuous process. The insight of this work could be a reference to other similar situations.

Model-based evaluation and model-free strategy for process development of three-column periodic counter-current chromatography.

Multi-column counter-current chromatography is an advanced technology used for continuous capture processes to improve process productivity, resin capacity utilization and product consistency. However, process development is difficult due to process complexity. In this work, some general and convenient guidances for three-column periodic counter-current chromatography (3C-PCC) were developed. Boundaries and distributions of operating windows of 3C-PCC processes were clarified by model-based predictions. Interactive effects of feed concentration (c0), resin properties (qmax and De), recovery and regeneration times (tRR) were evaluated over a wide range for maximum productivity (Pmax). Furthermore, variation of Pmax was analyzed considering the constraint factors (capacity utilization target and flow rate limitation). The plateau value of Pmax was determined by qmax and tRR. The operating conditions for Pmax were controlled by qmax, tRR and c0 interactively, and a critical concentration existed to judge whether the operating conditions of Pmax under constraints. Based on the comprehensive understanding on 3C-PCC processes, a model-free strategy was proposed for process development. The optimal operating conditions could be determined based on a set of breakthrough curves, which was used to optimize process performance and screen resins. The approach proposed was validated using monoclonal antibody (mAb) capture with a 3C-PCC system under various mAb and feed concentrations. The results demonstrated that a thorough model-based process understanding on multi-column counter-current chromatography is important and could improve process development and establish a model-free strategy for more convenient applications.

Process development and optimization of continuous capture with three-column periodic counter-current chromatography.

Continuous capture with affinity chromatography is one of the most important units for continuous manufacturing of monoclonal antibody (mAb). Due to the complexity of three-column periodic counter-current chromatography (3C-PCC), three approaches (experimental, model-based, and simplified approaches) were studied for process development and optimization. The effects of residence time for interconnected load (RT C ), breakthrough percentage of the first column for interconnected load (s) and feed protein concentration (c 0 ) on productivity and capacity utilization were focused. The model-based approach was found superior to the experimental approach in process optimization and evaluation. Two phases of productivity were observed and the optimal RT C for the maximum productivity was located at the boundary of the two phases. The comprehensive effects of the operating parameters (RT C , s, and c 0 ) were evaluated by the model-based approach, and the operation space was predicted. The best performance of 34.5 g/L/h productivity and 97.6% capacity utilization were attained for MabSelect SuRe LX resin under 5 g/L concentration at RT C = 2.8 min and s = 87.5%. Moreover, a simplified approach was suggested to obtain the optimal RT C for the maximum productivity. The results demonstrated that model-assisted tools are useful to determine the optimum conditions for 3C-PCC continuous capture with high productivity and capacity utilization.

Knockdown of annexin VII enhances nasopharyngeal carcinoma cell radiosensitivity in vivo and in vitro.

BACKGROUND: Radioresistance leads to treatment failure in patients with nasopharyngeal carcinoma (NPC). Thus, enhancing the radiosensitivity of NPC cells would likely increase the effectiveness of radiotherapy. Annexin VII (Annexin A7, ANXA7) might be a tumor promoter in NPC but its functions in radiosensitivity remain unclear. METHODS: NPC cell lines CNE2-shANXA7 and CNE2-pLKO.1 were generated and CNE2-shANXA7 nude mice xenograft tumor models were established. The main effects and molecular mechanisms of ANXA7 knockdown in NPC radiosensitivity were studied in vitro and in vivo by analyzing cell viability, clonogenicity, apoptosis, cell cycle distribution, tumor radioresponse and immunohistochemistry assay. RESULTS: ANXA7 knockdown revealed potentially enhanced NPC cell radiosensitivity via apoptosis and increased the cell number at the G2/M phase. In the xenograft model, NPC cells with ANXA7 knockdown were dramatically sensitive to irradiation and tumor growth was significantly suppressed. Compared to CNE2-pLKO.1 xenografts, CNE2-shANXA7 showed more γ-H2AX foci and less phospho-DNA PKcs. CONCLUSIONS: ANXA7 knockdown increased the radiosensitivity of NPC by enhancing apoptosis, modulating the cell cycle distribution into more radiosensitive phases, promoting DNA damage, and inhibiting repair. We showed that decreased ANXA7 levels enhanced radiosensitivity and provided insights into the therapeutic targets for NPC radiotherapy.

A novel angle on helical blade placement in trochanteric fractures - The axis-blade angle.

INTRODUCTION: For trochanteric fractures, helical blade placement is crucial to the prognosis of operations. Existing measurement methods used for blade placement include the Cleveland zone, the tip-apex distance (TAD), the calcar-referenced tip-apex distance (CalTAD), and the Parker's ratio. These methods all lack a direct view on blade direction. The current study proposed the axis-blade angle (ABA) to solve direction problem and investigated its clinical applicability. METHODS: A retrospective study collected 156 patients between May 2014 and February 2018. The occurrence of mechanical complications was analyzed in relation to age, gender, fracture side, American Society of Anesthesiologists classification, fracture classification, reduction quality, bone quality, the Cleveland zone, the Parker's ratio, the TAD, the CalTAD, and the ABA. RESULTS: 119 patients, including 25 with mechanical complications, were suitable for full analysis. In the univariate analysis, the Cleveland zone, reduction quality, the TAD, the CalTAD and the ABA were statistically associated with mechanical complications. In the multivariate analysis, reduction quality (p = 0.008) and the ABA (p < 0.001; adjusted OR 0.86;95% CI 0.77 to 0.96) showed significant results, which indicated that reduction quality and the ABA were two independent influencing factors for mechanical complications. Calculation of the receiver operating characteristic (ROC) curve indicated that the ABA was a reliable predictor of mechanical complications at the cut-off of -10°. CONCLUSIONS: The ABA provides instruction for the intraoperative adjustment of guide wire direction. Placing the helical blade with an ABA > -10° can effectively reduce the risk of mechanical complications.

Bioprosthetic pulmonary valve replacement: contemporary analysis of a large, single-center series of 170 cases.

OBJECTIVE: The present study was designed to compare stented porcine and bovine pericardial valves used for pulmonary valve replacement to better define valve performance and postoperative quality of life. METHODS: A retrospective review of all patients who underwent pulmonary valve replacement with a stented bioprosthesis from 1992 to 2008 was conducted. The medical records, imaging results, and quality of life questionnaires were analyzed. Differences in reintervention by valve type were determined using Cox proportional hazards models, controlling for subject age. RESULTS: A total of 170 consecutive pulmonary valve replacements (73 stented porcine, group 1; 97 bovine pericardial, group 2) were reviewed. No significant differences were seen in patient age or implanted valve size between the groups. Surgical mortality was 1.2%. The median follow-up was 48.2 months and was longer for group 2. No significant difference was seen in the risk of reintervention by valve type (hazard ratio, 0.64; 95% confidence interval, 0.18-2.34; P = .51). After 39 months of follow-up, pulmonary stenosis and pulmonary insufficiency that was moderate or worse were more common in patients who had undergone pulmonary valve replacement at younger than 15 years (pulmonary stenosis, 30.9% vs 10.0%, P = .003; pulmonary insufficiency, 46.2% vs 3.8%, P < .001), regardless of valve type. All patients performed well mentally and physically on the quality of life surveys. CONCLUSIONS: The present large series of stented bioprosthetic pulmonary valve replacements has demonstrated good results, particularly in adults, at intermediate follow-up. Freedom from reintervention was similar for the porcine and pericardial valves, and our finding did not clearly demonstrate the superiority of 1 type of valve. However, the stented bioprosthetic valves were less durable in younger patients.

Gibberellin 20-oxidase gene OsGA20ox3 regulates plant stature and disease development in rice.

Gibberellin (GA) 20-oxidase (GA20ox) catalyses consecutive steps of oxidation in the late part of the GA biosynthetic pathway. A T-DNA insertion mutant (17S-14) in rice, with an elongated phenotype, was isolated. Analysis of the flanking sequences of the T-DNA insertion site revealed that an incomplete T-DNA integration resulted in enhanced constitutively expression of downstream OsGA20ox3 in the mutant. The accumulation of bioactive GA(1) and GA(4) were increased in the mutant in comparison with the wild-type plant. Transgenic plants overexpressing OsGA20ox3 showed phenotypes similar to those of the 17S-14 mutant, and the RNA interference (RNAi) lines that had decreased OsGA20ox3 expression exhibited a semidwarf phenotype. Expression of OsGA20ox3 was detected in the leaves and roots of young seedlings, immature panicles, anthers, and pollens, based on ß-glucuronidase (GUS) activity staining in transgenic plants expressing the OsGA20ox3 promoter fused to the GUS gene. The OsGA20ox3 RNAi lines showed enhanced resistance against rice pathogens Magnaporthe oryzae (causing rice blast) and Xanthomonas oryzae pv. oryzae (causing bacterial blight) and increased expression of defense-related genes. Conversely, OsGA20ox3-overexpressing plants were more susceptible to these pathogens comparing with the wild-type plants. The susceptibility of wild-type plants to X. oryzae pv. oryzae was increased by exogenous application of GA(3) and decreased by S-3307 treatment. Together, the results provide direct evidence for a critical role of OsGA20ox3 in regulating not only plant stature but also disease resistance in rice.

[Experimental study of constructing vertebral canal on rabbit model with bone marrow mesenchymal stem cells].

OBJECTIVE: To construct the artificial lamina of vertebral arch with bone marrow mesenchymal stem cells transplanted in collagen sponge on a rabbit model and observe the growth of new bone. METHODS: To draw out the bone marrow blood from the femur of 2 weeks old rabbit and get the bone marrow mesenchymal stem cells by centrifugal and adhesive effect. To induce the MSCs to osteoblasts and transplant the induced cells in collagen sponge to construct the tissue engineering bone. To divide 48 rabbits into 3 groups randomly, namely group A, group B and group C. All of the rabbits are taken laminectomy in L6, and to group B and C, collagen sponge and tissue engineering bone are implanted in the operation area respectively. The artificial lamina of vertebral arch is determined qualitatively and quantitatively by methods including imageology and histomorphometry. RESULTS: The artificial lamina of vertebral arch is successfully constructed 4 weeks after operation in group C, CT examination at 4 weeks shows that new lamina of vertebral arch is formed, and the vertebral canal is intact. CONCLUSIONS: The artificial lamina of vertebral arch can be constructed successfully with the usage of tissue engineering bone transplanted bone marrow mesenchymal stem cells.

[Comparative study on the ultrastructure of radial artery in elderly patients underwent coronary artery bypass grafting with diabetes mellitus].

OBJECTIVE: To explore the impact of age and diabetes mellitus (DM) on the ultrastructure of radial artery (RA). METHODS: From June 2009 to December 2010, 64 patients underwent coronary artery bypass grafting (CABG) with autologous RA: 14 patients aged beyond 65 years without DM [9 male patients and 5 female patients, age (70 ± 4) years] and 18 patients aged beyond 65 years with DM [11 male patients and 7 female patients, age (68 ± 5) years], 20 patients aged under 60 years without DM [13 male patients and 7 female patients, age (53 ± 5) years] and 12 patients aged under 60 years with DM [7 male patients and 5 female patients, age (51 ± 6) years]. Four groups were subjected to routine electron microscopic examination and transmission electron microscopic examination. RESULTS: There were significant differences in percentage of endothelial denudation among four groups according to scanning electron microscopic evaluation (χ² = 18.082, P = 0.000). To compare with each other, there were significant differences between DM elderly patients and non-DM elderly patients, also between DM young patients and non-DM young patients according to scanning electron microscopic evaluation. There were no significant differences between DM elderly patients and DM young patients, also between non-DM elderly patients and non-DM young patients. Foam cells and the tendency of smooth muscle cells moving to intima could be visualized in DM patients according to transmission electron microscope. According to semiquantitative electron microscopic evaluation, non-DM young patients got the lower total scores than DM young patients (1.32 ± 0.20 vs. 4.38 ± 0.30) while non-DM elderly patients got the lower total scores than DM elderly patients (1.43 ± 0.20 vs. 4.67 ± 0.30). According to factorial design, there were significant differences between DM patients and non-DM patients (F = 41.22, P = 0.000). There were no differences between elderly patients and young patients (F = 1.24, P = 0.270). There is no interaction (F = 1.05, P = 0.309) between age and DM. CONCLUSIONS: After preoperative assessment with modified Allen's test and Doppler analysis, RA used as graft in the elderly has similar quality and function with young patients, and it may lead to a high patency in long term. However, the quality of RA in patients with DM is in bad condition, and further research on patency needs to be done.

[The morphometry and eNOS expression of radial artery in elderly patients with coronary atherosclerotic heart disease].

OBJECTIVE: To compare the morphometry and endothelial nitric oxide synthase (eNOS) expression of radial artery (RA) between young and elderly patients with coronary atherosclerotic heart disease. METHODS: From February 2008 to June 2009, 219 patients underwent coronary artery bypass grafting (CABG) with autologous RA, 57 patients aged beyond 70 years and 64 patients aged under 60 years. Before RA was harvested, a modified Allen test was routinely performed. If positive, RA would be further evaluated with Doppler ultrasound examination. In both groups RA was collected for HE staining to evaluate percentage of luminal narrowing (LN) and relationship between intima and media width at maximum intimal thickness (IMR). Immunofluorescence and Western blot were used to investigate the location and expression level of eNOS within the wall of RA. RESULTS: Morphometry of RA in both young and elderly patients represented mild or moderate intimal hyperplasia, and medial calcification was not found. LN in elderly patients was (22 ± 6)%, while in young patients, it was (23 ± 6)%. IMR in elderly patients was 0.36 ± 0.21, while in young patients, it was 0.42 ± 0.19. There was no significant difference in both LN and IMR between two groups (P > 0.05). Immunofluorescence indicated RA in both groups revealed a high expression of eNOS in intima and media, particularly in the smooth muscle of media. The values of relative integrated optical density in elderly patients was 1.21 ± 0.13, while in young patients, it was 1.25 ± 0.12. Also there was no significant difference in the expression level of eNOS within the wall of RA (P > 0.05). CONCLUSION: After preoperative assessment with modified Allen's test and Doppler analysis, RA used as graft in the elderly has similar quality and function with young patients, and it may lead to a high patency in long term.

[Experimental study on the option of antispasmodic drugs for radial artery in elderly patients with coronary atherosclerotic heart disease].

OBJECTIVE: To compare the relief effect of diltiazem, papaverine and nitroglycerin on radial artery spasm in elderly patients with coronary atherosclerotic heart disease. METHODS: Sixty patients aged beyond 70 years underwent coronary artery bypass grafting (CABG) with autologous radial artery from July 2009 to March 2010. Redundant radial artery was collected and the relief function of different drugs was evaluated through "organ bath" technique in vitro. All the patients were randomly divided into 3 groups based on different antispasmodic drugs: diltiazem, papaverine and nitroglycerin. Thirty seconds free blood flow of radial artery and hemodynamic parameters (heart rate, mean arterial pressure and central venous pressure) were assessed before and after intra-radial administration of diltiazem, papaverine and nitroglycerin in vivo. RESULTS: All three drugs could relieve radial artery spasm in different levels and the eventual relief rate was over 80%. Only nitroglycerin could relax radial artery completely, the relief capacity of nitroglycerin, diltiazem and papaverine decreased in order. There was no significant difference in the hemodynamic parameters before and after the injection. Blood flow of radial artery increased in nitroglycerin group [(42 ± 10) ml/30 s vs. (28 ± 7) ml/30 s, P < 0.05] while there was no significant difference in diltiazem [(23 ± 10) ml/30 s vs. (25 ± 8) ml/30 s, P > 0.05] and papaverine group [(25 ± 10) ml/30 s vs. (24 ± 9), P > 0.05]. CONCLUSIONS: Nitroglycerin could relieve vasospasm of radial artery effectively and increased blood flow. Nitroglycerin is the suitable antispasmodic drug for radial artery in the elderly patients with coronary atherosclerotic heart disease compare with diltiazem and papaverine.

[Surgical treatment of post-infarction left ventricular aneurysm: clinical analysis].

OBJECTIVE: To explore the clinical experiences, efficacies and postoperative left ventricular remodeling changes of surgical ventricular reconstruction in the treatment of post-infarction left ventricular aneurysm. METHODS: The investigators reviewed retrospectively the clinical data, operative approaches and follow-up outcomes of consecutive 194 patients with post-infarction left ventricular aneurysm, who underwent surgical ventricular reconstruction between January 1997 and December 2009. There were 54 cases in the linear group and 137 cases in the endoventricular patch plasty group. The changes of ventricular remodeling were measured by peri-operative and follow-up echocardiography. RESULTS: All patients underwent surgery with a mean cardiopulmonary bypass duration of (103 ± 35) min and aortic cross clamp duration of (62 ± 26) min. There were 8 per-operative deaths with a mortality rate of 2.2%. Angina pectoris of other cases disappeared and heart function greatly improved. After operation, the ventricular remodeling results showed that in the linear group, there was not significant difference in the changes of ventricular remodeling of post-op 2 weeks, 6 months, 1 year and 5 years versus pre-operation. However, in the endoventricular patch group, the changes of ventricular remodeling of post-op 2 weeks and follow-up 6 months versus pre-operation were significantly reduced (P < 0.05). End-systolic volume (LVESV) reduced from (129 ± 27) ml to (65 ± 8) ml and end-systolic volume index (LVESVI) decreased from (104 ± 14) ml/m(2) to (44 ± 6) ml/m(2) and the subgroup of LVEF < 35% was the most significant in the changes of LVESV and LVESVI. But LVEF improved significantly at post-operation and follow-up (from preoperation 42% ± 11% to 52% ± 7% during follow-up). CONCLUSIONS: For patients with infarction left ventricular aneurysm, left ventricular reconstruction is quite effective. The choice of operative approaches is determined by the size and range of ventricular aneurysm. Both string suture and endoventricular patch plasty technique can yield similarly satisfactory surgical outcomes. After operation, ventricular volume significantly decreases and cardiac function greatly improves.

[Comparative study of harvesting of radial artery and great saphenous vein in patients aged 65 years and older with coronary heart disease].

OBJECTIVE: To investigate the difference between autologous radial artery (RA) and great saphenous vein (GSV) harvesting in the elderly aged 65 years and older in coronary artery bypass grafting. METHODS: 171 patients aged 65 years and older underwent CABG with left internal mammary artery (LIMA), RA and GSV harvesting between January 2004 and June 2008. The harvesting time, length of conduits, intraoperative graft flow and harvest-site complications between RA and GSV was observed and follow-up was performed. RESULTS: A total of 171 RA and 171 GSV grafts were collected. The mean number of distal anastomoses was 3.20 +/- 0. 35. There was no significant difference in harvesting time, length of conduits and intraoperative graft flow between RA and GSV (29 +/- 10 min vs. 28 +/- 8 min, 18.2 cm +/- 1.5 cm vs. 21.3 cm +/- 5.7 cm and 41 ml/min +/- 19 ml/min vs. 34 ml/min +/- 9 m/min, P > 0.05), however, postoperatively,the length of wound healing and the incidence of infection, hematoma, exudation, paresthesia and tumescence of wound in RA was obviously lower than those in GSV (P < 0.05). CONCLUSIONS: Harvesting of RA in the elderly aged 65 years and older was superior to that of SVG and RA might play an more important role in CABG in the elderly.

Preliminary results of combined carotid endarterectomy and off-pump coronary artery bypass grafting in patients with coexistent carotid and coronary artery diseases.

BACKGROUND: Coexistent carotid and coronary artery diseases are common and patients with them remain at a high risk for perioperative stroke or myocardial infarction after coronary bypass surgery. The aim of this study was to investigate the effect of combined carotid endarterectomy (CEA) and off-pump coronary artery bypass grafting (CABG) in patients with coexistent carotid and coronary artery diseases. METHODS: Between January 2002 and December 2007, consecutive patients with coexistent carotid and coronary artery diseases underwent one-stage unilateral CEA and off-pump CABG in Heart Institute of Nanjing First Hospital Affiliated to Nanjing Medical University. Perioperative complications were assessed and follow-up was carried out. RESULTS: A total of 51 cases of isolated off-pump CABG and unilateral CEA, including 34 right and 17 left, were performed. The mean blocked time of carotid artery in CEA was (25.5 +/- 7.0) minutes. The mean number of distal grafts per patient was 3.30 +/- 0.45. The mean ventilation time, intensive care unit stay, and postoperative hospital stay was (11.3 +/- 5.4) hours, (2.1 +/- 0.9) days, and (12.5 +/- 6.1) days respectively. None of the patients had stroke or myocardial infarct. There was one perioperative death due to acute cardiac failure, resulting in an operative mortality of 1.96%. Follow-up was completed for 47 patients (92.16%) with a mean follow-up of (39.5 +/- 12.5) months. None of the patients manifested stroke, new angina or newly developed cardiac infarct. No late death occurred. CONCLUSION: Combined CEA and off-pump CABG is a safe and effective procedure in selected patients with coexistent carotid and coronary artery diseases.

[The effect of radial artery on coronary bypass surgery in patients aged 65 years and older].

OBJECTIVE: To investigate the effect of autologous radial artery (RA) on coronary artery bypass grafting (CABG) in the elderly aged 65 years and older. METHODS: Three hundreds and twenty-two patients aged 65 years and older underwent CABG with autologous RA from January 2000 to March 2007. Peri-operative complication and mortality were observed and follow-up was performed. RESULTS: Three hundreds and forty-four RA grafts including 300 cases of single and 22 cases of bilateral RA were collected. The total number of distal anastomosis was 974, with the mean of (3.0 +/- 0.4). The mean of RA distal anastomosis was (1.1 +/- 0.4). There were 321 single, 16 Y or T composite and 7 sequential grafts of RA constructed. The distal end of RA was anastomosed to right coronary artery system for 234 times, to obtuse marginal for 95 times, to diagonal or intermediate ramous artery for 22 times. The proximal end of RA was anastomosed to aorta for 328 times, to left internal mammary artery for 9 times and to saphenous vein for 7 times. Only 13 patients manifested transient paresthesia in the area of radial aspect of thumb and no other complication occurred in the forearm. During hospitalization, 7 patients died. No patient died after the follow-up of (46.5 +/- 6.7) months. Seventy-three patients were performed with coronary angiography postoperatively. It was showed by coronary angiography that all RA conduits were patent after the duration of (47.5 +/- 11.2) months after CABG. CONCLUSION: Utilization of RA to CABG in the elderly is safe and effective.

Role of radial artery in total arterial myocardial revascularization in coronary bypass surgery.

BACKGROUND: Total arterial revascularization (TAR) was widely utilized in coronary artery bypass grafting (CABG) as a result of its better long-term effect compared with vein grafts. Of the arterial conduits, radial artery (RA) gained popularity for its easy availability and reported long-term patency. Thus, the objective of this study was to investigate the effect of RA in TAR in CABG. METHODS: From January 2000 to December 2006, 85 patients (56 male and 29 female) at a mean age of 57.0 +/- 5.2 years, underwent TAR in CABG. RA and left internal mammary artery (LIMA) with composite Y or T and sequential grafting techniques were used. Post-operative complications were recorded and follow-up was performed. RESULTS: Eighty-five LIMA and 149 RA grafts including 21 single and 64 bilateral RA were collected. A total of 87 distal anastomoses were done with the LIMA and another 152 were done with the RA, with the mean number of distal anastomosis per patient of 2.81 +/- 0.47. The proximal RA ends were anastomsed directly to the aorta in 140 grafts with Y or T graft off in situ LIMA in 9, Y or T graft off RA in 9. The distal end was anastomsed to right coronary artery system in 92, to obtuse margina in 46, to diagonal in 19 and to ramous intermedius in 5. Nine sequential anastomoses were performed with RA. Nine composite Y or T grafts were constructed with RA and LIMA while another 9 were constructed with RA and RA. One (1.2%) patient died, 3 patients (3.5%) experienced acute renal failure and 2 (2.4%) developed stroke. All patients were still alive and no patient had evidences of newly occurred myocardial infarction or angina after a mean follow-up of 36.5 +/- 4.1 months (6 - 67 months). Postoperatively at 6 month, mean left ventricular ejective fraction was increased to 0.49 +/- 0.09, compared with that of 0.43 +/- 0.11 preoperatively (P = 0.027). Postoperative mean New York Heart Association class was 2.5 +/- 0.5, compared with that of 3.0 +/- 0.4 preoperatively (P = 0.003). CONCLUSIONS: TAR with arterial conduits of which RA was mainly used was proved in this study to be effective and safe in CABG.

[Analysis of the risk factors of acute renal insufficiency following coronary artery bypass grafting].

OBJECTIVE: To study the risk factors of acute renal insufficiency (ARI) following coronary artery bypass grafting (CABG). METHODS: The clinic data of 2242 patients undertaking CABG between July 1997 and July 2006 were retrospectively analyzed, and ARI following CABG was included. RESULTS: ARI occurred in 219 patients, with an incidence of 9.8%. Univariate analysis revealed that advanced age, diabetes mellitus, preoperative chronic renal dysfunction, left main disease, low left ventricular erection faction, emergency operation, on-pump CABG, ascending aortic atherosclerosis, postoperative respiratory function insufficiency and low cardiac output syndrome were significantly related to ARI following CABG, and logistic multivariate regression analysis showed that presence of advanced age (P = 0.031), preoperatively chronic renal dysfunction (CrCl or= 150 micromol/L, P = 0.041), on-pump CABG (P < 0.001), postoperative respiratory function insufficiency (P = 0.013) and low cardiac output syndrome (P = 0.004) were independent risk factors of ARI. CONCLUSIONS: Advanced age, preoperatively chronic renal dysfunction, on-pump CABG, postoperative respiratory function insufficiency and low cardiac output syndrome are the risk factors of ARI following CABG.

Overexpression of the AP2/EREBP transcription factor OPBP1 enhances disease resistance and salt tolerance in tobacco.

Osmotin promoter binding protein 1 (OPBP1), an AP2/EREBP-like transcription factor of tobacco (Nicotiana tabacum), was isolated using a yeast one-hybrid system. RNA gel blot analysis indicated that expression of the OPBP1 gene was induced by elicitor cryptogein, NaCl, ethephon, methyl jasmonate, as well as cycloheximide. Transient expression analysis using an OPBP1-eGFP fusion gene in onion epidermal cells revealed that the OPBP1 protein was targeted to the nuclear. Further, electrophoretic mobility shift assays demonstrated that the recombinant OPBP1 protein could bind to an oligonucleotide containing the GCC-box cis element. Transgenic tobacco plants with an over expression of the OPBP1 gene accumulated high levels of PR-1a and PR-5d genes and exhibited enhanced resistance to infection by Pseudomonas syringae pv tabaci and Phytophthora parasitica var nicotianae pathogens. They also exhibited increased tolerance to salt stress. These results suggest that OPBP1 might be a transcriptional regulator capable of regulating expression in sets of stress-related genes.