Dr. Sun's Procedure for Type A Aortic Dissection: Total Arch Replacement Using Tetrafurcate Graft With Stented Elephant Trunk Implantation

Sun's procedure is a modified elephant trunk technique that integrates the advantages of open surgical and endovascular repairs as a treatment of type A aortic dissection. It is named after Dr. Li-Zhong Sun and refers to total arch replacement using a four-branched graft with implantation of a special stented endovascular graft. Since its introduction, it has produced excellent early and late clinical outcomes. We present a video of this procedure and make an overview regarding the technical aspects, surgical indications, and clinical outcomes of Sun's procedure.

"T-shaped" repair for commissural detachment in acute type A aortic dissection

Aortic insufficiency in patients with type A aortic dissection is commonly seen and, in most cases, is the consequence of commissural detachment. We report our method of aortic valve repair in which the valve commissure and detached intima are repaired by using a "T-shaped" polyester patch that fits well within the aortic root after removal of the clots in the proximal false lumen. The early results have proved this is an easy and effective way to repair valve commissural detachment and reconstruct the aortic root.

[Construction of inducible lentiviral vector containing human Notch1 and EGFP gene and its expression in PC12 cells]

OBJECTIVE

To construct inducible lentiviral vector containing human Notch1 intracellular domain (NICD) gene and enhanced green fluorescent protein (EGFP), and to study its expression in PC12 cells.

METHODS

NICD cDNA was amplified by RT-PCR from human placenta tissue. EGFP gene was amplified by PCR from pEGFP-C1. Both NICD and EGFP were cloned into pcDNA 3.1 (+) plasmid to form pcDNA3.1-Notch1-EGFP. Then the Notch1-EGFP fragment was separated and cloned into pLVX-Tight-puro to form pLVX-Notch1-EGFP. The lentivirus were packaged and harvested, which were used to infect PC12 cells. After antibody selection for 2 weeks, the PC12 cells were induced by doxycycline (Dox). The expression of Notch1-EGFP was detected by fluorescence microscope and flow cytometry.

RESULTS

The recombinant inducible lentiviral vectors (pLVX-Notch1-EGFP) were success fully constructed. The EGFP positive cell percentage was over 90% in transfected PC12 cells after 500 ng/ml Dox induction for 36 h. The expression of Notch1 was posited correlated to the Dox concentration. The expression of Notch1 increased with the duration of Dox induction, which got the peak at 36 h after Dox induction.

CONCLUSION

The recombinant inducible lentiviral vectors containing Notch1 and EGFP gene are successfully constructed, which provides an effective and simple method to regulate the expression of Notch1 in PC12 cells.

Involvement of ERK1/2 signaling in proliferation of eight liver cell types during hepatic regeneration in rats

It has been well established that ERK1/2 signaling, often subdivided into nine types of pathways, can regulate the hepatocyte proliferative response during liver regeneration. However, the effect of ERK1/2 signaling on the proliferation of other hepatic cell types remains unclear. We isolated and purified 8 liver cell types at 10 time points after 2/3 hepatectomy in adult rats. For each cell type, mRNA expression changes for ERK1/2 signaling-involved genes were monitored up to 168 h, using microarrays. Real-time PCR assays were performed for array data verification. The expression levels of these genes varied considerably between different cell types. Integrating microarray results with gene synergical analysis, at the priming phase, activation of integrin/Grb2/Ras pathway in hepatocytes apparently contributed to G0/G1 transition. Two other pathways, G-protein/EPAC/Rap1 and G-protein/PKA/Rap1, were stimulated in hepatic stellate cells, while RTK/PKC/Ras and RTK/Grb2/Ras were stimulated in Kupffer cells. At the progressive phase, the ERK1/2 pathway is involved in hepatocyte replication; three pathways, namely Ca(2+)/PKC/Ras, RTK/Grb2/Ras and G-protein/EPAC/Rap1, were found to play roles in biliary epithelial cell proliferation, while RTK/PKC/Ras and RTK/Grb2/Ras were involved in Kupffer cell proliferation, and G-protein/PKC/Ras in pit cell proliferation. At the terminal phase, the promotive effect of the ERK1/2 pathway on replication of hepatocytes, biliary epithelial cells, oval cells, hepatic stellate cells, Kupffer cells, and dendritic cells was considerably reduced, possibly due to their differentiation at the end of regeneration. G-protein/PKC/Ras, integrin/Grb2/Ras and G-protein/ PKA/Rap1 pathways were active in sinusoidal endothelial cells, perhaps to aid in their proliferation. We conclude that ERK1/2 has a signaling role in the regulation of proliferation of 8 cell types during liver regeneration process.

Repair of Aortic Regurgitation due to Takayasu Arteritis

<p><b>Background:</b> Prosthetic valve detachment after aortic valve replacement and pseudoaneurysm formation are the most important postoperative complications in patients with Takayasu arteritis with aortic regurgitation. We reviewed our experience of surgical treatment of aortic regurgitation in patients with Takayasu disease.</p><p>Methods: Between November 1997 and September 2011, 11 patients (4 women and 7 men) with Takayasu arteritis with aortic regurgitation underwent surgical treatment. The age of the patients ranged from 26 to 56 years (mean, 40 � 9 years). Primary isolated aortic valve replacement was performed in 1 patient, David procedure in 1 patient, Wheat procedure in 1 patient, Bentall procedure in 2 patients, and Cabrol procedure in 6 patients (including 2 patients who underwent primary aortic valve replacement in other hospitals before being admitted to our surgical team).</p><p><b>Results:</b> There was no in-hospital death. All patients had an uneventful recovery during the postoperative course and were discharged. Prosthetic valve detachment, pseudoaneurysm formation at the suture line, and dilatation of the ascending aorta were not found in patients with composite aortic root replacement during a mean follow-up of 98 � 45 months. One patient died during follow-up.</p><p><b>Conclusion:</b> Valve detachment after composite aortic root replacement was not observed in patients with Takayasu disease with aortic regurgitation. Satisfactory surgical outcomes were obtained using composite aortic root replacement. However, close follow-up was needed to assess the effectiveness of the Cabrol procedure in patients with Takayasu disease with aortic regurgitation.</p>

Characterization of the interaction between astrocytes and encephalitogenic lymphocytes during the development of experimental autoimmune encephalitomyelitis (EAE) in mice

The nature of pathogenic mechanisms associated with the development of multiple sclerosis (MS) have long been debated. However, limited research was conducted to define the interplay between infiltrating lymphocytes and resident cells of the central nervous system (CNS). Data presented in this report describe a novel role for astrocyte-mediated alterations to myelin oligodendrocyte glycoprotein (MOG)(35-55) -specific lymphocyte responses, elicited during the development of experimental autoimmune encephalitomyelitis (EAE). In-vitro studies demonstrated that astrocytes inhibited the proliferation and interferon (IFN)-γ, interleukin (IL)-4, IL-17 and transforming growth factor (TGF)-β secretion levels of MOG(35-55) -specific lymphocytes, an effect that could be ameliorated by astrocyte IL-27 neutralization. However, when astrocytes were pretreated with IFN-γ, they could promote the proliferation and secretion levels of MOG(35-55) -specific lymphocytes, coinciding with apparent expression of major histocompatibility complex (MHC)-II on astrocytes themselves. Quantitative polymerase chain reaction (qPCR) demonstrated that production of IL-27 in the spinal cord was at its highest during the initial phases. Conversely, production of IFN-γ in the spinal cord was highest during the peak phase. Quantitative analysis of MHC-II expression in the spinal cord showed that there was a positive correlation between MHC-II expression and IFN-γ production. In addition, astrocyte MHC-II expression levels correlated positively with IFN-γ production in the spinal cord. These findings suggested that astrocytes might function as both inhibitors and promoters of EAE. Astrocytes prevented MOG(35-55) -specific lymphocyte function by secreting IL-27 during the initial phases of EAE. Then, in the presence of higher IFN-γ levels in the spinal cord, astrocytes were converted into antigen-presenting cells. This conversion might promote the progression of pathological damage and result in a peak of EAE severity.

Total arch replacement in patients with aortic dissection with an isolated left vertebral artery

BACKGROUND

The presence of an isolated left vertebral artery requires changes in the aortic arch reconstruction techniques and cerebral protection methods in patients with total arch replacement. The best method for surgical repair of the isolated left vertebral artery is controversial. We retrospectively reviewed our experience of total arch replacement in patients with aortic dissection with this vessel anomaly.

METHODS

Between August 2003 and December 2008, 21 patients with aortic dissection (type A dissection, n = 20; type B dissection, n = 1) with an isolated left vertebral artery underwent total arch replacement under hypothermic cardiopulmonary bypass combined with selective cerebral perfusion. Concomitant stented elephant trunk was implanted in 20 patients.

RESULTS

There was no in-hospital death. Injury to the spinal cord occurred in 2 patients with chronic dissection using stented elephant trunk implantation. One had weakness in the left lower extremity, and the other patient had paraparesis: both recovered during the follow-up period. One patient experienced transient neurologic deficit, and acute renal failure was observed in 1 patient: both recovered completely before hospital discharge.

CONCLUSIONS

Acceptable results were obtained in patients with aortic dissection with an isolated left vertebral artery. Although there was no clear evidence that the spinal cord injury was related to the isolated left vertebral artery using stented elephant trunk implantation, the isolated left vertebral artery was constructed as soon as possible in patients with this vessel anomaly.

First Report of Tomato yellow leaf curl virus Infecting Common Bean in China

Common bean (Phaseolus vulgaris) is one of the most economically important vegetable crops in China. In November 2011, symptoms with thickening and crumpling of leaves and stunting were observed on common bean with incidence rate of 50 to 70% in the fields of Huaibei, northern Anhui Province, China. Diseased common bean plants were found to be infested with large population of whiteflies (Bemisia tabaci), which induced leaf crumple symptoms in healthy common beans, suggesting begomovirus etiology. To identify possible begomoviruses, 43 symptomatic leaf samples from nine fields were collected and total DNA of each sample was extracted. PCR was performed using degenerate primers PA and PB to amplify a specific region covering AV2 gene of DNA-A and part of the adjacent intergenic region (2). DNA fragments were successfully amplified from 37 out of 43 samples and PCR amplicons of 31 samples were used for sequencing. Sequence alignments among them showed that the nucleotide sequence identity ranged from 99 to 100%, which implied that only one type of begomovirus might be present. Based on the consensus sequences, a primer pair MB1AbF (ATGTGGGATCCACTTCTAAATGAATTTCC) and MB1AsR (GCGTCGACAGTGCAAGACAAACTACTTGGGGACC) was designed and used to amplify the circular viral DNA genome. The complete genome (Accession No. JQ326957) was 2,781 nucleotides long and had the highest sequence identity (over 99%) with Tomato yellow leaf curl virus (TYLCV; Accession Nos. GQ352537 and GU199587). These samples were also examined by dot immunobinding assay using monoclonal antibody against TYLCV and results confirmed that TYLCV was present in the samples. These results demonstrated that the virus from common bean is an isolate of TYLCV, a different virus from Tomato yellow leaf curl China virus (TYLCCNV). TYLCV is a devastating pathogen causing significant yield losses on tomato in China since 2006 (4). The virus has also been reported from cowpea in China (1) and in common bean in Spain (3). To our knowledge, this is the first report of TYLCV infecting common bean in China. References: (1) F. M. Dai et al. Plant Dis. 95:362, 2011. (2) D. Deng et al. Ann. Appl. Biol. 125:327, 1994. (3) J. Navas-Castillo et al. Plant Dis. 83:29, 1999. (4) J. B. Wu et al. Plant Dis. 90:1359, 2006.

Surgery for type B dissection using a short-stented elephant trunk procedure

BACKGROUND

Stent grafting is a very important treatment for type B dissection. Some patients are unsuitable for endograft repair because of inadequate proximal and/or distal fixation zones. We reviewed our experience of proximal descending thoracic replacement combined with short-stented elephant trunk implantation for type B dissection for patients without adequate fixation zones for endografts.

METHODS

Twenty-one patients with type B dissection (10 acute, 11 chronic) underwent this procedure between August 2003 and December 2007. After replacement of the proximal descending thoracic aorta, a short-stented elephant trunk was implanted into the residual descending thoracic aorta. The residual false lumen was evaluated post-operatively using computed tomography (CT) scans.

RESULTS

There were no in-hospital deaths. One death was observed during a mean follow-up of 69 ± 15 months. One patient with preoperative shock suffered paraparesis but recovered postoperatively. One patient had paraplegia and was lost to follow-up. Cerebral hemorrhage was observed in 1 patient, but he recovered. Thrombus obliteration of the false lumen around the stented elephant trunk was observed in 19 patients (95%) and at the diaphragmatic level in 17 patients (85%) during follow-up.

CONCLUSION

Replacement of the proximal descending thoracic aorta combined with short-stented elephant trunk implantation was a suitable alternative for type B dissection for patients without adequate fixation zones for endografts (particularly for young subjects). This procedure allowed enlargement of the true lumen, re-establishment of the true lumen, induction of thrombosis of the false lumen, and shrinkage of the aorta. Injury to the spinal cord, however, was an intractable problem.

Platelet-targeted microbubbles inhibit re-occlusion after thrombolysis with transcutaneous ultrasound and microbubbles

Microbubbles (MBs) can augment the acoustic cavitation' (US), thereby facilitating the thrombolysis of external ultrasound. But we observed re-thrombosis after successful thrombolysis by MBs and transcutaneous ultrasound in an endothelium injury model. This study was designed to explore whether platelet-targeted MBs can prevent the reformation of thrombi. Arterial injury was induced in canine femoral arteries with balloon, and the arteries were completely thrombotically occluded. The arteries were treated with intra-arterial MBs or platelet-targeted MBs (TMB) and transcutaneous low frequency ultrasound (LFUS) to achieve complete thrombolysis. The arterial flow was monitored with angiogram for 4h following treatment. Results showed that both MBs and TMBs produced successful dissolution of clots in the presence of ultrasound. The re-occlusion began to occur 1h after thrombolysis in MB/LFUS treatment, and 7 of 8 arteries were re-occluded within 3h. Most of the arteries (7 of 8) in the TMB/LFUS group remained patent for 4h following treatment. The flow tended to decrease after thrombolysis in MB/LFUS treatment. These results indicated that platelet-targeted microbubbles were beneficial in preventing re-thrombosis in vivo and microbubbles served as good carrier of thrombolytic and anticoagulation drugs.

Design of shared instruments to utilize simulated gravities generated by a large-gradient, high-field superconducting magnet

A high-field superconducting magnet can provide both high-magnetic fields and large-field gradients, which can be used as a special environment for research or practical applications in materials processing, life science studies, physical and chemical reactions, etc. To make full use of a superconducting magnet, shared instruments (the operating platform, sample holders, temperature controller, and observation system) must be prepared as prerequisites. This paper introduces the design of a set of sample holders and a temperature controller in detail with an emphasis on validating the performance of the force and temperature sensors in the high-magnetic field.

Optical negative refraction in ferrofluids with magnetocontrollability

We numerically demonstrate optical negative refraction in ferrofluids containing isotropic Fe3O4 nanoparticles, each having an isotropic Ag shell, in the presence of an external dc magnetic field H. The all-angle broadband optical negative refraction with magnetocontrollability arises from H-induced chains or columns. They result in hyperbolic equifrequency contour for transverse magnetic waves propagating in the system. The finite element simulations verify the analyses using the effective medium approximation. Experimental demonstration and potential applications are suggested and discussed.

Effect of tramadol on immune responses and nociceptive thresholds in a rat model of incisional pain

OBJECTIVE

To evaluate the effects of tramadol on the proinflammatory responses in a rat model of incisional pain by investigating its effects on nociceptive thresholds and serum interleukin-6 (IL-6) and IL-2 levels.

METHODS

Forty-two male Sprague-Dawley (SD) rats scheduled for plantar incision were randomly divided into 7 groups (n=6 in each group). Rats in Group 1 receiving general anesthesia with no incision were served as control; At 30 min before skin incision, Groups 2 to approximately 5 were given 5 ml normal saline or 1, 10, and 20 mg/kg tramadol, respectively, intraperitoneally (i.p.); Group 6 received 10 mg/kg tramadol after operation; Group 7 received 10 mg/kg tramadol before incision, followed by 200 microg/kg naloxone after operation. Mechanical allodynia was measured by electronic von Frey filament to evaluate the nociceptive thresholds 1 h before incision, and 1 h and 2 h after operation. Serum IL-6 and IL-2 levels were measured by enzyme-linked immunosorbent assay (ELISA) 2 h after operation.

RESULTS

Mechanical thresholds decreased significantly and serum IL-6 level increased significantly after operation in Group 2 compared with control (P<0.01), and these changes were reversed respectively by tramadol in a dose-dependent manner (P<0.05 and P<0.01, respectively). IL-2 level remained unchanged after operation in Group 2, but decreased in Group 3 (P<0.05), then gradually returned to the normal level in Groups 4 and 5. The intraperitoneally injected tramadol (10 and 20 mg/kg) produced a potent and dose-dependent antinocicptive effect on the lesioned paw. The antinocicptive effects of tramadol were partially antagonized by naloxone (200 microg/kg), suggesting an additional non-opioid mechanism.

CONCLUSION

The results suggest that tramadol could be a good choice for the treatment of pain under the conditions that immunosuppression may be particularly contraindicated.

Adipose-derived stem cells from pregnant women show higher proliferation rate unrelated to estrogen

BACKGROUND

Adipose tissue contains an abundant population of multipotent adipose-derived stem cells (ASCs) and has been an excellent source of mesenchymal stem cells for cell therapy and tissue engineering. To ensure successful cell therapies, consistency of stem cell performance across donors is critical. However, the effect of the donor's reproductive status on ASC proliferation rate and differentiation capacity is undefined.

METHODS

We investigated whether the yield and function of ASCs are affected by the woman's reproductive status: pregnancy, premenopause or menopause. ASCs were isolated from the abdomen of 15 women and their proliferation rates and differentiation capacities were compared by cell count. The capacity of ASCs to differentiate into the chondrogenic lineage was investigated by quantitative real-time polymerase chain reaction and immunohistochemistry.

RESULTS

There was no significant difference in the differentiation capacity between the three groups, whereas the proliferation rate of ASCs from pregnant women was significantly higher than from the other two groups (P < 0.05). The proliferation rate of ASCs after estrogen treatment remained unchanged.

CONCLUSIONS

Despite the higher proliferation rate in pregnant women, ASCs showed consistency in cell differentiation capacity and were unaffected by donor status. This suggests that factors other than estrogen are responsible for the difference in proliferation.

Enhanced bioaugmentation of petroleum- and salt-contaminated soil using wheat straw

A new bioaugmentation method for petroleum- and salt-contaminated soil was presented, in which wheat straw was used to enhance salt leaching and subsequent petroleum degradation by a bacteria-fungi consortium of Enterobacter cloacae and Cunninghamella echinulata. The effectiveness of a coarse wheat straw layer in inhibiting capillary-induced upward salt movement and in enhancing growth of E. cloacae and C. echinulata was shown in the laboratory and a 7000-m(2) field study in Henan Province, China. In the field study, the Na(+) concentration in remediated soil at 1-25 cm depth decreased from 1597 ± 394 to 543 ± 217 mg kg(-1), while Cl(-) decreased from 1520 ± 922 to 421 ± 253 mg kg(-1). The wheat straw increased bacterial biomass by 170-fold and fungi 11-fold compared to control soil without wheat straw. The concentration of total petroleum hydrocarbons decreased from 6320 ± 1180 to 2260 ± 420 mg kg(-1) after 45 d of treatment. Wheat was cultivated on remediated soil and grain yield reached 72% of that obtained in normal farmland adjacent to the study site. The results demonstrated the effectiveness of wheat straw in enhancing bioaugmentation of the petroleum- and salt-contaminated soil and indicated a high application potential.

Spinal cord changes after the evacuation of a spinal subdural haematoma

Spinal subdural haematoma is a rare entity. Only a few cases have been reported, mainly in patients with coagulopathies or bleeding diathesis, and also in patients undergoing anticoagulant therapy following surgery, trauma, or lumbar puncture. Symptoms of spinal cord compression produced by spinal subdural haematoma may progress rapidly causing complete and irreversible deficits. However, rapid diagnosis and surgical intervention can result in a good functional outcome for the patient. We report on a 41-year-old woman with a normal coagulation profile who developed a spinal subdural haematoma after a minor motor vehicle accident. Although initially asymptomatic, she developed a dense quadriparesis over a 36-h period. A magnetic resonance imaging study demonstrated a subdural mass compressing the spinal cord, and at surgery a spinal subdural haematoma was found. She was discharged to an inpatient rehabilitation facility. Follow-up at 1 year showed significant improvement in motor function, but absence of posterior column function. A follow-up magnetic resonance study demonstrated widening of the spinal cord, advanced myelomalacia and a large, central, multi-loculated syrinx.