In carbohydrate chemistry, the stereoselective synthesis of 1,2-cis-glycosides remains a formidable challenge. This complexity is comparable to the synthesis of 1,2-cis-β-D-mannosides, primarily due to the adverse anomeric and Δ-2 effects. Over the past decades, to attain β-stereoselectivity in D-rhamnosylation, researchers have devised numerous direct and indirect methodologies, including the hydrogen-bond-mediated aglycone delivery (HAD) method, the synthesis of β-D-mannoside paired with C6 deoxygenation, and the combined approach of 1,2-trans-glycosylation and C2 epimerization. This review elaborates on the advancements in β-D-rhamnosylation and its implications for the total synthesis of tiacumicin B and other physiologically relevant glycans.
Glycosides ; Mannosides ; Glycosylation ; Stereoisomerism

Objective:To explore values and differences of multi-modality image registration and normalization methods in 18F-AV45 PET quantitative analysis of Alzheimer′s disease (AD). Methods:Twenty AD patients (10 males, 10 females; age (77.0±5.8) years) and 20 normal controls (NC; 8 males, 12 females; age (75.2±4.8) years) from the AD neuroimaging initiative (ADNI) open database of the National Institute on Aging were analyzed. β-amyloid (Aβ) deposition (positive/negative) was assessed by visual analysis. The SUV ratio (SUVr) in each brain region and individual average SUVr were calculated using template normalization method (M1), normalization after registration with 18F-FDG PET or MRI image (M2 or M3) respectively with the cerebellum as the reference area. The intra-class correlation coefficient (ICC) was used to complete the reliability between methods, and independent-sample t test and one-way repeated measures analysis of variance were used to compare the differences of quantitative indexes between different groups and different methods. ROC curve analysis was used to compare the diagnostic efficacy in distinguishing AD and NC, Aβ positive and negative cases. Results:There were 15 and 6 patients with positive Aβ deposition in AD group and in NC group respectively by visual analysis. The SUVrs of three methods were with good consistency (ICC=0.82, P<0.001), and the differences among individual average SUVrs (1.29±0.17, 1.36±0.23, 1.45±0.24) were significant ( F=68.78, P<0.001). There were significant differences between AD group (1.39±0.17, 1.48±0.24, 1.58±0.25) and NC group (1.20±0.10, 1.24±0.15, 1.33±0.16; t values: 3.55-4.33, all P<0.05), Aβ positive group (1.39±0.16, 1.50±0.21, 1.59±0.23) and negative group (1.19±0.11, 1.21±0.14, 1.31±0.15; t values: 4.58, 5.11, 4.41, all P<0.001), and the individual average SUVr of M3 was higher (both P<0.001). The AUCs of distinguishing Aβ positive and negative deposition of M1-M3 were 0.86, 0.88, 0.84 and the thresholds of SUVrs were 1.29, 1.37, 1.52, respectively. Conclusion:The three multi-modality registration and normalization methods are reliable methods for quantitation of 18F-AV45 PET imaging with certain differences, and should be selected carefully based on data conditions in practice.

Objective:To discuss the challenges and problems of the prevention and control of emerging infectious diseases in Shanghai as a megacities.Methods:An imported case of cutaneous anthrax occurred in Shanghai on May 30, 2019. Shanghai Municipal Center for Disease Control & Prevention conducted an epidemiological investigation and treatment of the cases; after this case, the data of patients with cutaneous anthrax were collected, and an epidemiological study was conducted. Meanwhile, the wound and blood samples of the patient were collected for laboratory testing.Results:Of the seven wound samples of the patient, 6 were positive for the Bacillus anthracis nucleic acid test, and the double serological test results showed a 4-fold increase in the titer of anthrax antibodies. Shanghai CDC conducted an epidemiological investigation of the confirmed cases and observed its contacts. After treatment, the patients recovered, and no other issues appeared among the 19 contacts. Conclusions:Shanghai must strengthen the training of clinicians on emerging infectious diseases to achieve early detection, diagnosis, and treatment of imported infectious diseases and reduce the incidence, spread, and death of the diseases. At the same time, multi-department joint prevention and control are needed to prevent and control secondary cases.

Objective: To retrospectively analyze the distribution of non-fermentative bacteria causing bloodstream infection in hospitalized patients in Sichuan Province and their drug susceptibility to common antibiotics for better understanding their epidemiological characteristics. Methods: From January 1, 2015 to December 31, 2017, all of the non-fermentative bacteria isolated from patients with bloodstream infection in nine hospitals in Sichuan Province were collected. Species distribution and drug resistance test results were retrospectively analyzed. Results: A total of 6 291 strains of pathogenic bacteria were isolated, including 3 674 strains of gram-negative bacteria (58.4%) and 2 617 strains of gram-positive bacteria (41.6%). The gram-positive bacteria were 1 895 strains of Staphylococcus (30.1%), 372 strains of Streptococcus (5.9%), 317 strains of Enterococcus (5.1%) and 33 strains of other gram-positive bacteria (0.5%). The gram-negative bacteria were 3 191 Enterobacteriaceae strains (50.7%), 389 non-fermentative strains (6.2%) and 94 other gram-negative strains (1.5%). The isolated non-fermentative bacteria were mainly Pseudomonas aeruginosa (136 strains, 35.0%), Acinetobacter baumannii (126 strains, 32.0%) and Stenotrophomonas maltophilia (33 strains, 8.5%). There were 167 (42.9%), 112 (28.8%) and 82 (21.1%) non-fermentative bacteria isolated in internal medicine departments, ICUs and surgery departments, respectively. The drug resistance rates of Pseudomonas aeruginosa to cefepime, ciprofloxacin and gentamicin were 16.5%, 10.7% and 9.9%, respectively. Carbapenems-resistant Pseudomonas aeruginosa (CR-PA) accounted for 13.6%. No polymyxin-resistant Pseudomonas aeruginosa was found. The resistance rates of Acinetobacter baumannii to all antibiotics were over 30% except for minocycline and polymyxin and 75.7% of carbapenem-resistant Acinetobacter baumannii (CR-AB) were isolated. The drug resistance rates to levofloxacin, trimethoprim/sulfamethoxazole and ceftazidime were 0%, 0% and 37.0% in Stenotrophomonas maltophilia isolates and 10.5%, 4.2% and 19% in Burkholderia cepacia isolates, respectively. Conclusions Non-fermentative bacteria causing 6.2% of bloodstream infection in Sichuan, mainly by Pseudomonas aeruginosa and Acinetobacter baumannii. There were significant differences in the isolation rate of non-fermentative bacteria in different departments and most of the strains were isolated in internal medicine departments. The detection rate of Acinetobacter baumannii with multiple drug resistance was high, while other non-fermentative bacteria had good sensitivity to antibiotics.

Objective To examine whether Tim-3 plays a protective role in paraquat poisoning induced excessive immune response and tissue damage based on the critical roles of Tim-3 controlling inflammatory response.Methods A paraquat poisoning model was established in wild type and in Tim-3 transgenic C57BL/6 mice by intraperitoneal injection of paraquat (40 mg/kg) .In addition, C57BL/6 mice with paraquat poisoning were injected with Tim-3 soluble protein( sTim-3) or control protein to see the effect of Tim-3 blocking on the progression of paraquat poisoning.Samples were collected at 6 and 24 h after paraquat injection respectively and were examined for tissue damage, cytokine expression and paraquat metabolism.Results After paraquat poisoning, there was significantly attenuated tissue damage in the lungs and kidneys and decreased TNF-α,IL-6 and IL-1 beta expression in the PBMCs or in the serum from Tim-3 transgenic mice compared to wild type mice.The serum concentration of paraquat in Tim-3 transgenic mice was also significantly decreased.However, in sTim-3 treated paraquat poisoning mice, there was significantly increased cytokine expression and tissue damage compared to control protein treated mice.The in vitro data showed that Tim-3 signaling negatively regulated macrophages mediated inflammatory response.Conclusion Tim-3 plays a critical role in maintaining the homeostasis after paraquat poisoning. Further investigation on the regulatory roles of Tim-3 in inflammation will shed new light on the pathogenesis of paraquat poisoning and provide new therapeutic strategies.

Objective:To explore the regulatory effect of Hsf 1 on PLC/PRF5 hepatoma cells proliferation.Methods: By shRNA gene silencing technology ,constructed PLC/PRF5 hepatoma cell line of Hsf 1 gene silencing.To detect the expression of Hsf 1, p53 and Rb proteins in PLC/PRF5 hepatoma cells by Western blot.The proliferation of PLC/PRF5 cell line was observed by methylthiazolyl tetrazolium assay ( MTT ) , plate clone formation assay ( PCFA ) and cell cycle assay.Results: shRNA-Hsf1 could significantly inhibit the expression of Hsf 1 in PLC/PRF5 cells.It could induce PLC/PRF5 cells stopping at G1 phase of cell cycle , inhibit cell proliferation and colonal formation;silencing Hsf1 caused up-regulation of p53 and Rb proteins expression in PLC/PRF5 cells.Conclusion: Silencing Hsf1 is involved in up-regulation of p53 and Rb proteins expression , which results in inhibiting proliferation of PLC/PRF5 hepatoma cells.

Pigment epithelium-derived factor (PEDF) is an antiangiogenic factor which is effective in tumour inhibition in a variety of tumours and has not yet been studied in bladder tumour before. In this study the expression of PEDF, interleukin-1α (IL-1α) and -8 (IL-8) in bladder tumours was investigated. Immunohistochemistry was performed on 64 bladder tumour and 23 normal uroepithelium samples. Expression change of the factors was compared with clinicopathological parameters. Correlations between PEDF, IL-1α and IL-8 were analyzed. None of the factors was in relation to gender, tumour occurrence, and size or onset pattern. PEDF (P=0.014) and IL-1α (P=0.049) expression was down-regulated with grade progression. PEDF expression was lower in normal uroepithelium than in papillary urothelial neoplasm of low malignant potential (PUNLMP) (P=0.000) and carcinoma (P=0.009) whilst IL-1α (P=0.000 and P=0.000 respectively) and IL-8 (P=0.000 and P=0.023 respectively) expression was higher in the same grouping. PEDF expression had a negative correlation with IL-8 in PUNLMP (P=0.049, r=-0.578) as well as in tumour grouping (P=0.033, r=-0.276). Deranged expressional change of PEDF, IL-1α and IL-8 could be in relation to loss of differentiation from normal uroepithelium to papillary lesion and eventually to carcinoma.

Pigment epithelium-derived factor (PEDF) is an antiangiogenic factor which is effective in tumour inhibition in a variety of tumours and has not yet been studied in bladder tumour before.In this study the expression of PEDF,interleukin-1 α (IL-1α) and -8 (IL-8) in bladder tumours was investigated.Immunohistochemistry was performed on 64 bladder tumour and 23 normal uroepithelium samples.Expression change of the factors was compared with clinicopathological parameters.Correlations between PEDF,IL-1α and IL-8 were analyzed.None of the factors was in relation to gender,tumour occurrence,and size or onset pattem.PEDF (P=0.014) and IL-1α (P=0.049) expression was down-regulated with grade progression.PEDF expression was lower in normal uroepithelium than in papillary urothelial neoplasm of low malignant potential (PUNLMP) (P=0.000) and carcinoma (P=0.009) whilst IL-1α (P=0.000 and P=0.000 respectively) and IL-8 (P=0.000 and P=0.023 respectively) expression was higher in the same grouping.PEDF expression had a negative correlation with IL-8 in PUNLMP (P=0.049,r=-0.578) as well as in tumour grouping (P=0.033,r=-0.276).Deranged expressional change of PEDF,IL-1 α and IL-8 could be in relation to loss of differentiation from normal uroepithelium to papillary lesion and eventually to carcinoma.

Objective To study the clinical effects of treating radiodermatis with acupoint massage and wet compress of Chinese medicine. Methods 104 patients with radiodermatis were randomly recruited into a control group and a treatment group, with 52 patients in each group. The treatment group was treated with acupoint massage plus wet compress of chiense medicines; with the treatment group was externally applied with Kangbao Shaoshang moistening ointment. The result was compared after the treatment. Results The time for easement of pain in the treatment group was obvious reduced than the control group after the treatment. The total effective rate was 96.1% and 57.69% in the treatment group and the control group respectively, the difference showing statistical significance (χ2=27.3, P＜0.01). Conclusion It was effective to treat radiodermatitis with acupoint massage and wet compress of Chinese medicine.

Objective To compare the diagnostic efficacy and complications of transperineal prostate biopsy for<10 cores biopsy vs≥10 cores biopsy. Methods Nine hundred transrectal ul-trasound-guided transperineal prostate biopsies were performed. Patients were divided into 2 groups, <10 cores group and ≥10 cores group. Patient numbers of the 2 groups were 759 and 141, respec-tively. Cancer positive rate and complications were compared between the 2 groups retrospectively. Results Cancer positive rates were 41.6%(316/759) and 51.8%(73/141) in 2 groups (P<0.05). In patients of PSA≤10.0 ng/ml, cancer positive rates were 6.8% (16/235) and 17.8% (8/45) in 2 groups (P<0.05). Gross hematuria was the most common complication associated with biopsy. There was no statistical difference between the 2 groups in post-biopsy gross hematuria rate. Conclu-sions The diagnostic efficacy is higher in≥10 cores prostate biopsy than that in <10 cores prostate biopsy, There is no difference in biopsy related complications regarding biopsy core numbers.