Acinetobacter baumannii is currently posing a serious threat to global health. Lipopolysaccharide (LPS) is a potent virulence factor of pathogenic Gram‐negative bacteria. To explore the antigenic ...properties of A. baumannii LPS, four Kdo‐containing inner core glycans from A. baumannii strain ATCC 17904 were synthesized. A flexible and divergent method based on the use of the orthogonally substituted α‐Kdo‐(2→5)‐Kdo disaccharides was developed. Selective removal of different protecting groups in these key precursors and elongation of sugar chain via α‐stereocontrolled coupling with 5,7‐O‐di‐tert‐butylsilylene or 5‐O‐benzoyl protected Kdo thioglycosides and 2‐azido‐2‐deoxyglucosyl thioglycoside allowed efficient assembly of the target molecules. Glycan microarray analysis of sera from infected patients revealed that the 4,5‐branched Kdo trimer was a potential antigenic epitope, which is attractive for further immunological research to develop carbohydrate vaccines against A. baumannii.
Four inner core oligosaccharides from the lipopolysaccharide (LPS) of A. baumannii strain ATCC 17904 were chemically synthesized (see structures). Antigenic investigation indicated that the 4,5‐branched Kdo trisaccharide, a common inner core structure of A. baumannii LPS, is a potential antigenic epitope that could be used for further immunological research to develop diagnostic tools or vaccines against A. baumannii.
An efficient α‐sialylation methodology for various primary, secondary, and tertiary alcohol acceptors has been developed. The sialic acid ethyl thioglycoside 1b, bearing a 4‐nitropicoloyl moiety as ...the stereodirecting group at the C4 position, was utilized as the glycosyl donor, and the sialylation reaction was activated with N‐iodosuccinimide and catalytic triflic acid in a 1:1 mixture of dichloromethane/acetonitrile as solvent. The method was successfully applied to the stereocontrolled synthesis of protected trisaccharide 11 found in the repeating unit of serotype Ia Group B Streptococcus capsular polysaccharide.
The sialic acid ethyl thioglycoside donor, bearing a 4‐nitropicoloyl moiety as the stereodirecting group at the C4 position, can successfully achieve highly α‐sialylation with various acceptors. The method has been extended to the stereocontrolled synthesis of the protected trisaccharide found in the repeating unit of serotype Ia Group B Streptococcus capsular polysaccharide.
The stereodirecting effect of C5-ester functions on the glycosylation stereoselectivity of 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) ethyl thioglycoside donors is presented. The coupling of ...5-O-arylcarbonyl or acetyl protected Kdo thioglycosides with acceptors proceeds in an α-selective and high-yielding manner, leading to formation of α-linked Kdo glycosides products. On the other hand, the glycosylation stereoselectivity of the 5-O-2-quinolinecarbonyl (Quin) or 4-nitropicoloyl substituted Kdo thioglycoside donors is switchable: (1) The glycosylation of the 5-O-Quin carrying Kdo donors with primary glycosyl acceptors shows complete β-stereoselectivity, furnishing the corresponding β-glycosides in good-to-excellent yield. (2) The stereochemical outcome of the secondary acceptors with these Kdo donors is determined mainly by the stereoelectronic nature of the acceptor. Only or predominant α anomeric products are obtained when the Kdo donors couple with the disarmed or highly crowded secondary carbohydrate acceptors, while the selectivity may switch to predominant β in the glycosylation of the 5-O-4-nitropicoloyl carrying donor with more reactive secondary alcohols. The synthetic use of the newly developed Kdo donors 1c and 7b has been demonstrated by facile preparation of a structurally unique trisaccharide motif 19 which possesses both α- and β-Kdo glycosidic bonds.
Acinetobacter baumannii is currently posing a serious threat to global health. Lipopolysaccharide (LPS) is a potent virulence factor of pathogenic Gram‐negative bacteria. To explore the antigenic ...properties of A. baumannii LPS, four Kdo‐containing inner core glycans from A. baumannii strain ATCC 17904 were synthesized. A flexible and divergent method based on the use of the orthogonally substituted α‐Kdo‐(2→5)‐Kdo disaccharides was developed. Selective removal of different protecting groups in these key precursors and elongation of sugar chain via α‐stereocontrolled coupling with 5,7‐O‐di‐tert‐butylsilylene or 5‐O‐benzoyl protected Kdo thioglycosides and 2‐azido‐2‐deoxyglucosyl thioglycoside allowed efficient assembly of the target molecules. Glycan microarray analysis of sera from infected patients revealed that the 4,5‐branched Kdo trimer was a potential antigenic epitope, which is attractive for further immunological research to develop carbohydrate vaccines against A. baumannii.
Four inner core oligosaccharides from the lipopolysaccharide (LPS) of A. baumannii strain ATCC 17904 were chemically synthesized (see structures). Antigenic investigation indicated that the 4,5‐branched Kdo trisaccharide, a common inner core structure of A. baumannii LPS, is a potential antigenic epitope that could be used for further immunological research to develop diagnostic tools or vaccines against A. baumannii.
Non-traumatic injury accounts for approximately half of clinical spinal cord injury, including chronic spinal cord compression. However, previous rodent spinal cord compression models are mainly ...designed for rats, few are available for mice. Our aim is to develop a thoracic progressive compression mice model of spinal cord injury. In this study, adult wild-type C57BL/6 mice were divided into two groups： in the surgery group, a screw was inserted at T9 lamina to compress the spinal cord, and the compression was increased by turning it further into the canal（0.2 mm） post-surgery every 2 weeks up to 8 weeks. In the control group, a hole was drilled into the lamina without inserting a screw. The results showed that Basso Mouse Scale scores were lower and gait worsened. In addition, the degree of hindlimb dysfunction in mice was consistent with the degree of spinal cord compression. The number of motor neurons in the anterior horn of the spinal cord was reduced in all groups of mice, whereas astrocytes and microglia were gradually activated and proliferated. In conclusion, this progressive compression of thoracic spinal cord injury in mice is a preferable model for chronic progressive spinal cord compression injury.
Background Hepatic arterial infusion chemotherapy for liver metastases is under evaluation because of the high target dose and low general toxicity. To investigate the efficacy and safety of a ...Folfox4 regimen administered through a combined hepatic arterial and systemic infusion for the first-line treatment of colorectal cancer （CRC） with unresectable liver metastases. Methods Twenty-seven CRC patients with unresectable hepatic metastases and no prior chemotherapy were enrolled into the study. They received a Folfox4 regimen; 1st day： HAl of oxaliplatin 85 mg/m2 and L-folinic acid 200 mg/m2, followed by a bolus hepatic arterial injection of 5-fluorouracil 400 mg/m2, then continuous HAl of 5-FU 600 mg/m2; 2nd day： infusion of L-folinic acid 200 mg/m2 i.v. followed by an intravenous bolus injection of 5-Fluorouraci1400 mg/m2, then continuous infusion of 5-fluorouracil 600 mg/m2 i.v. The patients received HAl during the odd cycles, and the intravenous administration of the same Folfox4 regimen during the even cycles. Results A total of 236 treatment cycles were given with a median of 10 cycles. The therapy generated the following results after six treatment cycles： complete response （CR） 1/27 （3.7%）, partial response （PR） 17/27 （63.0%）, stable disease （SD） 6/27 （22.2%）, and progress disease （PD） 3/27 （11.1%）. Five patients had hepatectomy. The serum levels of both carcinoembryonic antigen （CEA） and CA19-9 were significantly reduced （P〈0.05）. A median time to progression of 11 months and a median overall survival of 24 months were documented. The major adverse events included grade 1/2 nausea/vomiting, upper abdominal pain, peripheral neuropathy, and neutropenia/thrombocytopenia. Conclusions The Folfox4 regimen administered through combined hepatic arterial and systemic infusions is efficacious and safe for the treatment of CRC with unresectable liver metastases, and it facilitates the control of local lesions.
Background Indirect traumatic optic neuropathy （TON） is an acute injury of the optic nerve associated with severe visual dysfunction, which may be a result of secondary mechanical injury and vascular ...disorder of the optic nerve due to trauma. We analyzed the natural course of axonal loss and blood flow disturbances in patients with indirect TON to find a possible therapeutic window. Methods A cohort of 54 patients with indirect TON recruited between October 2008 and October 2010 at Beijing Tongren Hospital was retrospectively analyzed. The patients were divided into no light perception group （NLP） and better than NLP （btNLP） group. Specifically, the thickness of the retinal nerve fiber layer （RNFL） measured by spectral domain optical coherence tomography （SD-OCT）, and hemodynamic parameters of the ophthalmic artery （OA）, central retinal artery （CRA） and posterior ciliary artery （PCA） were determined. Results Two weeks after injury, there was a statistically significant decrease in the thickness of RNFL in the btNLP group as compared with the fellow control eyes （P 〈0.05）. In contrast, in the NLP group, RNFL thickness slightly increased for 2 weeks following injury, then overtly reduced after 4 weeks （P 〈0.05）. Peak systolic velocity （PSV） of CRA was significantly decreased 4 weeks after injury （P 〈0.05） in both the NLP group and btNLP group （P 〈0.05）. The thickness of RNFL in the NLP group was negatively correlated with PSV of CRA after 1 week of injury （P 〈0.05, r=-0.962）. Conclusions SD-OCT is a useful supplement in detecting the axonal loss in TON. The dynamic change of the thickness of RNFL appears to correlate with the hemodynamic disturbances in the natural course of TON. The first 2 weeks following an injury is critical and should be considered as the therapeutic window for TON patients.
To overcome the shortcomings of existing robot localization sensors, such as low accuracy and poor robustness, a high precision visual localization system based on infrared-reflective artificial ...markers is designed and illustrated in detail in this paper. First, the hardware system of the localization sensor is developed. Secondly, we design a novel kind of infrared-reflective artificial marker whose characteristics can be extracted by the acquisition and processing of the infrared image. In addition, a confidence calculation method for marker identification is proposed to obtain the probabilistic localization results. Finally, the autonomous localization of the robot is achieved by calculating the relative pose relation between the robot and the artificial marker based on the perspective-3-point （P3P） visual localization algorithm. Numerous experiments and practical applications show that the designed localization sensor system is immune to the interferences of the illumination and observation angle changes. The precision of the sensor is ±1.94 cm for position localization and ±1.64° for angle localization. Therefore, it satisfies perfectly the requirements of localization precision for an indoor mobile robot.
Silicon carbide architecture with different morphology has been synthesized via catalyst-free carbothermic reduction of silica under normal atmosphere pressure.X-ray powder diffraction(XRD)and ...Scanning electron microscopy(SEM)were used to characterize the architecture.The results show that the mole ratio of carbon/silica has a great influence on the morphology of silicon carbide architecture.At different carbon/silica mole ratio,platelet-,bamboo-,pagoda-,and bead-like silicon carbide architecture have been synthesized.
AIM: To evaluate short-term outcomes following intraoperative biliary lavage for hepatolithiasis.METHODS: A total of 932 patients who were admitted to the West China Medical Center of Sichuan ...University between January 2010 and January 2014 and underwent bile duct exploration and lithotomy were retrospectively included in our study. The patients were divided into the lavage group and the control group. Related pre-, intra-, and postoperative factors were recorded, analyzed, and compared between the two groups in order to verify the effects of biliary lavage on the short-term outcome of patients with hepatolithiasis. RESULTS: Amongst the patients who were included, 678 patients with hepatolithiasis were included in the lavage group, and the other 254 patients were enrolled in the control group. Data analyses revealed that preoperative baseline and related intraoperative variables were not significantly different. However, patients who underwent intraoperative biliary lavage had prolonged postoperative hospital stays(6.67 d vs 7.82 d, P = 0.024), higher hospitalization fees(RMB 28437.1 vs RMB 32264.2, P = 0.043), higher positive rates of bacterial cultures from blood(13.3% vs 25.8%, P = 0.001) and bile(23.6% vs 40.7%, P= 0.001) samples, and increased usage of advanced antibiotics(26.3% vs 38.2%, P = 0.001). In addition, in the lavage group, more patients had fever(> 37.5℃, 81.4% vs 91.1%, P = 0.001) and hyperthermia(> 38.5℃,39.7% vs 54.9%, P = 0.001), and higher white blood cell counts within 7 d after the operation compared to the control group.CONCLUSION: Intraoperative biliary lavage might increase the risk of postoperative infection, while not significantly increasing gallstone removal rate.
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