Controllable 1,3-Bis-Functionalization of 2-Nitroglycals with High Regioselectivity and Stereoselectivity Enabled by a H-Bond Catalyst.

The selective modification of carbohydrates is significant for producing their unnatural analogues for drug discovery. C1-functionalization (glycosylation) and C1,C2-difunctionalization of carbohydrates have been well developed. In contrast, C3-functionalization or C1,C3-difunctionalization of carbohydrates remains rare. Herein, we report such processes that efficiently and stereoselectively modify carbohydrates. Specifically, we found that trifluoroethanol (TFE) could promote 1,3-bis-indolylation/pyrrolylation of 2-nitroglycals generated carbohydrate derivatives in up to 93% yield at room temperature; slightly reducing the temperature could install two different indoles at the C1- and C3-positions. Switching TFE to a bifunctional amino thiourea catalyst leads to the generation of C3 monosubstituted carbohydrates, which could also be used to construct 1,3-di-C-functionalized carbohydrates. This approach produced a range of challenging sugar derivatives (over 80 examples) with controllable and high stereoselectivity (single isomer for over 90% of the examples). The potential applications of the reaction were demonstrated by a set of transformations including the synthesis of bridged large-ring molecules and gram scale reactions. Biological activities evaluation demonstrated that three compounds exhibit a potent inhibitory effect on human cancer cells T24, HCT116, AGS, and MKN-45 with IC50 ranged from 0.695 to 3.548 µM.

Design and synthesis of guaianolide-germacranolide heterodimers as novel anticancer agents against hepatocellular carcinoma.

Inspired by our previous finding that disesquiterpenoids showed more potent antihepatoma cytotoxicity than their corresponding parent monomers, natural product-like guaianolide-germacranolide heterodimers were designed and synthesized from guaianolide diene and germacranolides via a biomimetic Diels-Alder reaction to provide three antihepatoma active dimers with novel scaffolds. To explore the structure-activity relationship, 31 derivatives containing ester, carbamate, ether, urea, amide, and triazole functional groups at C-14' were synthesized and evaluated for their cytotoxic activities against HepG2, Huh7, and SK-Hep-1 cell lines. Among them, 25 compounds were more potent than sorafenib against HepG2 cells, 15 compounds were stronger than sorafenib against Huh7 cells, and 17 compounds were stronger than sorafenib against SK-Hep-1 cells. Compound 23 showed the most potent cytotoxicity against three hepatoma cell lines with IC50 values of 4.4 µM (HepG2), 3.7 µM (Huh7), and 3.1 µM (SK-Hep-1), which were 2.7-, 2.2-, and 2.8-fold more potent than sorafenib, respectively. The underlying mechanism study demonstrated that compound 23 could induce cell apoptosis, prevent cell migration and invasion, cause G2/M phase arrest in SK-Hep-1 cells. Network pharmacology analyses predicted PDGFRA was one of the potential targets of compound 23, and surface plasmon resonance (SPR) assay verified that 23 had strong affinity with PDGFRA with a dissociatin constant (KD) value of 90.2 nM. These promising findings revealed that structurally novel guaianolide-germacranolide heterodimers might provide a new inspiration for the discovery of antihepatoma agents.

Application of xanthan gum and konjac gum to improve the texture, rheological properties and microstructure of Oviductus Ranae gel.

The effects of xanthan gum (XG), konjac gum (KG) and mixed gum of XG and KG (MG) on the gel properties of Oviductus Ranae (OR) were studied using texture analysis, dynamic rheometry, scanning electron microscopy and Fourier transform infrared spectroscopy. The addition of both XG and MG can increase the hardness and water-holding capacity and energy storage modulus of the OR gel, but the addition of KG has the opposite effect. When the mass ratio of XG to KG is 1:1, the hardness (730 g), springiness (1.00) and chewiness (218.48 g) of the OR gel are all maximized. The addition of MG significantly more enhances the hydrogen bond and hydrophobic interaction, compared with the addition of only XG or KG, so the OR gel forms a denser and more stable network structure. Our results provide valuable information for further design and preparation of OR gel foods containing XG and KG.

Alleviation of neoadjuvant immunochemotherapy for esophageal squamous cell carcinoma and its relationship with expression and changes of PD-L1.

The alleviation of neoadjuvant immunochemotherapy (NICT) and neoadjuvant chemoradiotherapy (NCRT) was compared for esophageal squamous cell carcinoma (ESCC), and the correlation between the expression and changes of PD-L1 and the efficacy of NICT was evaluated in this study. Fourteen patients with ESCC who received preoperative NICT were included in group A, and fourteen patients with ESCC who received preoperative NCRT were included in group B. Next, group A was divided into CR (complete response), PR (partial response), and NR (no response) according to the degree of pathological response. Also, the expression and changes of PD-L1 (CPS, TPS, IPS) before and after treatment were compared between the groups. We observed that after the treatment, the expression of PD-L1 in both groups was higher than before treatment. In group B, the expression of PD-L1 was elevated in 92.8% of patients, which was higher than that in group A, which had significantly increased IPS (p<0.05). In group A, 9 (64.2%) patients with CPS <10 achieved partial or complete response. There was no significant difference in pathological response and reduction of tumor thickness between the two groups or significant differences in CPS and TPS among CR, PR, and NR groups before treatment. The IPS was the highest in the CR group; however, the difference was not statistically significant. The differences in IPS change were significant among the three groups (p<0.05). In conclusion, NICT and NCRT could upregulate the expression of PD-L1. NCRT more significantly upregulated the expression of PD-L1, mainly of PD-L1 in immune cells in the tumor microenvironment. NICT was not less effective than NCRT in pathological response and tumor thickness changes. The preoperative CPS and TPS scores of PD-L1 did not effectively predict the degree of pathological response, but the high IPS and high IPS downregulation could be related to the degree of pathological response. Some patients with low preoperative expression of PD-L1 could still achieve a good response by NICT. As NCRT can upregulate the expression of PD-L1, the low preoperative expression of PD-L1 is no contraindication for immunotherapy, which provides a new basis and prognostic indexes for chemoradiotherapy combined with immunotherapy.

Primary undifferentiated pleomorphic sarcoma of the thyroid: A case report and review of the literature.

RATIONALE: Primary undifferentiated pleomorphic sarcoma is extremely rare in the thyroid, and can be easily misdiagnosed as anaplastic thyroid cancer. PATIENT CONCERNS: We present a case of a 71-year-old woman who presented with a rapidly growing painless mass in the neck. DIAGNOSES-INTERVENTIONS-OUTCOMES: Computed tomography showed a large hypointense mass with hyperdense areas involving whole of the right lobe of thyroid gland and fine-needle aspiration cytology found a few atypical cells. Surgical exploration was performed subsequently and frozen section showed malignant tumor. Therefore, a total thyroidectomy, central, and bilateral lateral neck dissection were performed and adjuvant radiotherapy of 60 Gy was administered. The patient was alive and had no recurrence at 6-month follow-up. LESSONS: Although primary undifferentiated pleomorphic sarcoma in the thyroid is extremely rare, patients who presented with a rapidly growing painless mass in the neck should be considered and it is essential to excise the tumor completely as soon as possible.

Isolation and identification of a novel rabies virus lineage in China with natural recombinant nucleoprotein gene.

Rabies virus (RABV) causes severe neurological disease and death. As an important mechanism for generating genetic diversity in viruses, homologous recombination can lead to the emergence of novel virus strains with increased virulence and changed host tropism. However, it is still unclear whether recombination plays a role in the evolution of RABV. In this study, we isolated and sequenced four circulating RABV strains in China. Phylogenetic analyses identified a novel lineage of hybrid origin that comprises two different strains, J and CQ92. Analyses revealed that the virus 3' untranslated region (UTR) and part of the N gene (approximate 500 nt in length) were likely derived from Chinese lineage I while the other part of the genomic sequence was homologous to Chinese lineage II. Our findings reveal that homologous recombination can occur naturally in the field and shape the genetic structure of RABV populations.

[Identification and sequential analysis on rabies virus isolated from a donkey].

OBJECTIVE: To identify and analyze the genetic characteristics of nucleoprotein (N) and glycoprotein (G) genes of rabies virus (RABV) isolated from a donkey in Wuhan. N gene and G gene of the virus were compared with other representative street strains isolated around Hubei areas as well as the vaccine strains used in China and abroad. METHODS: RABV in brain tissue of a donkey was detected by direct immunofluorescent method and then inoculated in suckling mice to observe the incidence of rabies. Brain samples of the donkey and infected suckling mice were detected by ELISA. The N gene and G gene fragment of the isolated RABV were amplified by RT-PCR and cloned into pMD18-T vector for sequencing and genetic analysis. RESULTS: RABVs were detected in both donkey brain and suckling mice brain samples. The N gene and G gene nucleotide homology of RABV isolated from the donkey with other representative street strains found around Hubei areas as well as vaccine strains used in China and abroad were 85.7% - 99.1% and 82.2% - 99.7%, and the deduced amino acid identity were 95.6% - 99.8% and 87.8% - 99.4%, respectively. CONCLUSION: Novel RABV was successfully identified and isolated from a donkey and showed close relationship to the representative street strains found around Hubei areas as well as vaccine strains used in China through genetic analysis.

[Temporal and spatial population dynamics of rabies virus isolates in China].

In order to study phylogeography, population dynamics and molecular evolution of rabies viruses (RABVs) isolates from China, especially spatio-temporal dynamics, the timescale of RABVs evolution and its pattern of migration, we performed an extensive comparative analysis of RABV N gene sequence data, representing 167 isolates sampled from 20 provinces in a 78-year period (from 1931 through 2009). The available Chinese isolates could be divided into two distinct clades:Phylogroup clades I comprised Chinese group 1-4; Phylogroup clades II contained Chinese group 5-8. We found no evidence for positive selection (dN/dS>1) acting at any codon and found strong selective constraints for N gene. Bayesian Markov Chain Monte Carlo (MCMC) analysis suggested that the Chinese rabies viruses originated within the last 2000 years and the mean rates of nucleotide substitution for the N gene were approximately 4 x 10(-4) substitutions per site per year. The analyses of the spatial and spatio-temporal evolution indicated that RABV isolates from China migrated among different Provinces.

[Construction and analysis of full-length cDNA clone of rabies virus street strain].

To construct a expression plasmid containing the full-length cDNA of rabies virus, four overlapped fragments covering full length cDNA of rabies virus street stain HN10 were cloned into pVAX1 sequentially in the genome except for the G-L noncoding region which was replaced with GFP gene. The plasmid containing the full-length viral cDNA was flanked by hammerhead ribozyme (HamRz) and hepatitis delta ribozyme (HdvRz) sequences and arranged under the control of the cytomegalovirus (CMV) promoter. The constructed plasmid could be directly used for the following procedure of producing the recombinant rabies virus street HN10.

A molecular epidemiological study targeting the glycoprotein gene of rabies virus isolates from China.

A group of 31 rabies viruses (RABVs), recovered primarily from dogs, one deer and one human case, were collected from various areas in China between 1989 and 2006. Complete G gene sequences determined for these isolates indicated identities of nucleotide and amino acid sequences of >or=87% and 93.8%, respectively. Phylogenetic analysis of these and some additional Chinese isolates clearly supported the placement of all Chinese viruses in Lyssavirus genotype 1 and divided all Chinese isolates between four distinct groups (I-IV). Several variants identified within the most commonly encountered group I were distributed according to their geographical origins. A comparison of representative Chinese viruses with other isolates retrieved world-wide indicated a close evolutionary relationship between China group I and II viruses and those of Indonesia while China group III viruses formed an outlying branch to variants from Malaysia and Thailand. China group IV viruses were closely related to several vaccine strains. The predicted glycoprotein sequences of these RABVs variants are presented and discussed with respect to the utility of the anti-rabies biologicals currently employed in China.

[Application of McAbs against rabies nucleocapsid in diagnosis of rabies street virus].

OBJECTIVE: McAbs against rabies nucleocapsid were used to detect rabies street viruses in animal brain specimens with indirect immunofluorescent assay to evaluate the sensitivity and specificity of this assay. METHODS: 62 specimen from rabid animal brains including genotype 1 to 7 and 271 specimens from different normal animal brains collected in Pasteur Institute in 2003 were tested and compared, using indirect immunofluorescent assay. All these specimens were identified and compared using rapid rabies enzyme immunodiagnosis, fluorescent antibody test and rabies virus isolation assay in neuroblastoma cell culture which were all provided by Pasteur Institute. RESULTS: Both sensitivity and the specificity of the indirect immunofluorescent assay were 100%. CONCLUSION: The results showed a positive of rabies virus detection with these methods.