N-acetylneuraminic acid modulates SQSTM1/p62 sialyation-mediated ubiquitination degradation contributing to vascular endothelium dysfunction in experimental atherosclerosis mice.

Sialic acid (SIA) has been reported to be a risk factor for atherosclerosis (AS) due to its high plasma levels in such patients. However, the effect of increasing SIA in circulation on endothelial function during AS progression remains unclear. In the present study, ApoE-/- mice and endothelial cells line (HUVEC cells) were applied to investigate the effect of SIA on AS progression and its potential molecular mechanism. In vivo, mice were injected intraperitoneally with Neu5Ac (main form of SIA) to keep high-level SIA in circulation. ORO, H&E, and Masson staining were applied to detect the plaque progression. In vitro, HUVECs were treated with Neu5Ac at different times, CCK-8, RT-PCR, western blot, and immunoprecipitation methods were used to analyze its effects on endothelial function and the potential involved mechanism. Results from the present study showed that high plasma levels of Neu5Ac in ApoE-/- mice could aggravate the plaque areas as well as increase necrotic core areas and collagen fiber contents. Remarkably, Neu5Ac levels in circulation displayed a positive correlation with AS plaque areas. Furthermore, results from HUVECs showed that Neu5Ac inhibited cells viability in a time/dose-dependent manner, by then induced the activation of inflammation makers such as ICAM-1 and IL-1ß. Mechanism study showed that the activation of excessive autophagy medicated by SQSTM1/p62 displayed an important role in endothelium inflammatory injury. Neu5Ac could modify SQSTM1/p62 as a sialylation protein, and then increase its level with ubiquitin binding, further inducing ubiquitination degradation and being involved in the excessive autophagy pathway. Inhibition of sialylation by P-3Fax-Neu5Ac, a sialyltransferase inhibitor, reduced the binding of SQSTM1/p62 to ubiquitin. Together, these findings indicated that Neu5Ac increased SQSTM1/p62-ubiquitin binding through sialylation modification, thereby inducing excessive autophagy and subsequent endothelial injury. Inhibition of SQSTM1/p62 sialylation might be a potential strategy for preventing such disease with high levels of Neu5Ac in circulation.

Toxin genotypes, antibiotic resistance and their correlations in Clostridioides difficile isolated from hospitals in Xi'an, China.

BACKGROUND: Clostridioides difficile is the main pathogen of antimicrobial-associated diarrhoea and health care facility-associated infectious diarrhoea. This study aimed to investigate the prevalence, toxin genotypes, and antibiotic resistance of C. difficile among hospitalized patients in Xi'an, China. RESULTS: We isolated and cultured 156 strains of C. difficile, representing 12.67% of the 1231 inpatient stool samples collected. Among the isolates, tcdA + B + strains were predominant, accounting for 78.2% (122/156), followed by 27 tcdA-B + strains (27/156, 17.3%) and 6 binary toxin gene-positive strains. The positive rates of three regulatory genes, tcdC, tcdR, and tcdE, were 89.1% (139/156), 96.8% (151/156), and 100%, respectively. All isolates were sensitive to metronidazole, and the resistance rates to clindamycin and cephalosporins were also high. Six strains were found to be resistant to vancomycin. CONCLUSION: Currently, the prevalence rate of C. difficile infection (CDI) in Xi'an is 12.67% (156/1231), with the major toxin genotype of the isolates being tcdA + tcdB + cdtA-/B-. Metronidazole and vancomycin were still effective drugs for the treatment of CDI, but we should pay attention to antibiotic management and epidemiological surveillance of CDI.

Novel STAT3 oligonucleotide compounds suppress tumor growth and overcome the acquired resistance to sorafenib in hepatocellular carcinoma.

Signal transducer and activator of transcription 3 (STAT3) plays an important role in the occurrence and progression of tumors, leading to resistance and poor prognosis. Activation of STAT3 signaling is frequently detected in hepatocellular carcinoma (HCC), but potent and less toxic STAT3 inhibitors have not been discovered. Here, based on antisense technology, we designed a series of stabilized modified antisense oligonucleotides targeting STAT3 mRNA (STAT3 ASOs). Treatment with STAT3 ASOs decreased the STAT3 mRNA and protein levels in HCC cells. STAT3 ASOs significantly inhibited the proliferation, survival, migration, and invasion of cancer cells by specifically perturbing STAT3 signaling. Treatment with STAT3 ASOs decreased the tumor burden in an HCC xenograft model. Moreover, aberrant STAT3 signaling activation is one of multiple signaling pathways involved in sorafenib resistance in HCC. STAT3 ASOs effectively sensitized resistant HCC cell lines to sorafenib in vitro and improved the inhibitory potency of sorafenib in a resistant HCC xenograft model. The developed STAT3 ASOs enrich the tools capable of targeting STAT3 and modulating STAT3 activity, serve as a promising strategy for treating HCC and other STAT3-addicted tumors, and alleviate the acquired resistance to sorafenib in HCC patients. A series of novel STAT3 antisense oligonucleotide were designed and showed potent anti-cancer efficacy in hepatocellular carcinoma in vitro and in vivo by targeting STAT3 signaling. Moreover, the selected STAT3 ASOs enhance sorafenib sensitivity in resistant cell model and xenograft model.

Progress in biological activities and biosynthesis of edible fungi terpenoids.

The edible fungi have both edible and medicinal functions, in which terpenoids are one of the most important active ingredients. Terpenoids possess a wide range of biological activities and show great potential in the pharmaceutical and healthcare industries. In this review, the diverse biological activities of edible fungi terpenoids were summarized with emphasis on the mechanism of anti-cancer and anti-inflammation. Subsequently, this review focuses on advances in knowledge and understanding of the biosynthesis of terpenoids in edible fungi, especially in the generation of sesquiterpenes, diterpenes, and triterpenes. This paper is aim to provide an overview of biological functions and biosynthesis developed for utilizing the terpenoids in edible fungi.

Coordination of intertracheid pit traits and climate effects among cycads.

Interconduit pit membranes, which are permeable regions in the primary cell wall that connect to adjacent conduits, play a crucial role in water relations and the movement of nutrients between xylem conduits. However, how pit membrane characteristics might influence water-carbon coupling remains poorly investigated in cycads. We examined pit characteristics, the anatomical and photosynthetic traits of 13 cycads from a common garden, to determine if pit traits and their coordination are related to water relations and carbon economy. We found that the pit traits of cycads were highly variable and that cycads exhibited a similar tradeoff between pit density and pit area as other plant lineages. Unlike other plant lineages (1) pit membranes, pit apertures, and pit shapes of cycads were not coordinated as in angiosperms; (2) cycads exhibited larger pit membrane areas but lower pit densities relative to ferns and angiosperms, but smaller and similar pit membrane densities to non-cycad gymnosperms; (3) cycad pit membrane areas and densities were partially coordinated with anatomical traits, with hydraulic supply of the rachis positively coordinated with photosynthesis, whereas pit aperture areas and fractions were negatively coordinated with photosynthetic traits; (4) cycad pit traits reflected adaptation to wetter habitats for Cycadaceae and drier habitats for Zamiaceae. The large variation in pit traits, the unique pit membrane size and density, and the partial coordination of pit traits with anatomical and physiological traits of the rachis and pinna among cycads may have facilitated their dominance in a variety of ecosystems from the Mesozoic to modern times.

Programmed Cell Death Protein 1/Programmed Cell Death Ligand 1 Signaling Pathway Mediated Interleukin-10 and Bacterial Biofilm Formation to Drug Resistance Mechanism of Pneumoniae Meningitis.

It aimed to explore the resistance and biofilm formation characteristics of pneumococcal meningitis (PM) and the mechanism of programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) signaling pathway (SPW). Firstly, the drug susceptibility test of 32 Streptococcus pneumoniae strains isolated from patients with PM and the biofilm semi-quantitative determination was performed. Then, the PM mouse model was constructed. The differences in brain morphology, blood-brain barrier (BBB) permeability, water content, cytokines such as interferon-γ (IFN-γ), interleukin-10 (IL-10), and chemokine C-X-C ligand 10 (CXCL10), and levels of PD-1 and PD-L1 in the normal control (NC), sham operation, PM, and PD-1 antibody (PM + PD-1 Ab)groups were compared and analyzed. The results showed that streptococcus pneumoniae had multidrug resistance, and the thickness of biofilm decreased with the increase of penicillin minimum inhibitory concentration (MIC). Compared with the NC and Sham groups, BBB permeability, water content, levels of IFN-γ and IL-10, and PD-1 and PD-L1 were signally increased in the PM and PM + PD-1 Ab groups, while CXCL10 level was decreased, exhibiting differences withP<0.05. Based on the PM group, BBB permeability, water content, levels of IFN-γ and CXCL10, and PD-1 and PD-L1 were remarkably decreased in the PM + PD-1 Ab group, while the IL-10 level was observably increased (P<0.05). Therefore, high-MIC penicillin could inhibit the thickness of Streptococcus pneumoniae biofilm, while blocking the PD-1/PD-L1 pathway exerted an improving effect on the PM symptoms.

Axial Convex-Shaped Hematoma was Associated with Poor Curative Effect of Surgical Treatment for Traumatic Posterior Fossa Epidural Hematoma in Children.

BACKGROUND: Posterior fossa epidural hematoma (PFEDH) is rare which accounts for just 4-12.9% of all EDH cases. Since its frequently subtle and nonspecific clinical presentation, CT scan has great importance for early diagnosis and treatment of PFEDH. However, indications for surgery depending on the findings of CT image are still controversial. METHODS: We retrospectively analyzed 40 pediatric cases of PFEDH. Their baseline characteristic, clinical presentation, imaging findings and outcomes were collected and analyzed. The ellipsoid volume equation X × Y × Z/2 was used to measure the hematoma volume. The Glasgow Outcome Scale (GOS) was used to assess the neurologic functional outcome. RESULTS: A total of 40 pediatric PFEH patients were included with 8 patients having poor outcome and 32 patients having a relatively good prognosis. GCS score showed a significant difference between good and poor outcome groups (p < 0.001). Y value on CT image was significantly bigger in poor outcome group than good outcome group (p < 0.01). Similar results were got in X/Z value (p < 0.05) and Y/Z value (p < 0.01) which reflected the shape of hematoma. A predictive model with Y + X/Z showed the largest area under the ROC curve with a sensitivity of 75.0% and specificity of 93.7%. CONCLUSIONS: GCS score at admission was closely related to the prognosis of the pediatric patients with PFEDH. The morphometry of PFEDH has a crucial role in judging the prognosis. Axial convex-shaped hematoma was associated with poor curative effect of surgical treatment.

Neural Radiance Fields-Based 3D Reconstruction of Power Transmission Lines Using Progressive Motion Sequence Images.

To address the fuzzy reconstruction effect on distant objects in unbounded scenes and the difficulty in feature matching caused by the thin structure of power lines in images, this paper proposes a novel image-based method for the reconstruction of power transmission lines (PTLs). The dataset used in this paper comprises PTL progressive motion sequence datasets, constructed by a visual acquisition system carried by a developed Flying-walking Power Line Inspection Robot (FPLIR). This system captures close-distance and continuous images of power lines. The study introduces PL-NeRF, that is, an enhanced method based on the Neural Radiance Fields (NeRF) method for reconstructing PTLs. The highlights of PL-NeRF include (1) compressing the unbounded scene of PTLs by exploiting the spatial compression of normal L∞; (2) encoding the direction and position of the sample points through Integrated Position Encoding (IPE) and Hash Encoding (HE), respectively. Compared to existing methods, the proposed method demonstrates good performance in 3D reconstruction, with fidelity indicators of PSNR = 29, SSIM = 0.871, and LPIPS = 0.087. Experimental results highlight that the combination of PL-NeRF with progressive motion sequence images ensures the integrity and continuity of PTLs, improving the efficiency and accuracy of image-based reconstructions. In the future, this method could be widely applied for efficient and accurate 3D reconstruction and inspection of PTLs, providing a strong foundation for automated monitoring of transmission corridors and digital power engineering.

Recent advances in the tumor-penetrating peptide internalizing RGD for cancer treatment and diagnosis.

Cancer has become a prominent disease that seriously endangers human health. The complexity of the biological characteristics of the tumor makes it challenging for traditional therapeutic drugs to penetrate tumor tissues and exert their antitumor effects. Internalizing RGD peptide (iRGD) is a novel tumor-homing peptide that binds to αvß3 and αvß5 integrins on the surface of tumor vessels through the C-end rule (CendR) motif. The CendR motif binds to the neuropilin-1 (NRP-1) receptor on tumor cells, initiating NRP-1-mediated transcytosis to facilitate drug entry into the tumor tissue. Multiple studies demonstrated that iRGD improved the penetration and targeting of antitumor drugs, thereby enhancing their antitumor efficacy. In this review, we initially described the origins of iRGD and its penetration mechanism. Furthermore, we presented updates on the application of iRGD in cancer chemotherapy, photodynamic therapy, gene therapy, immunotherapy, treatment with antibodies or protein-based biologics, and tumor imaging.

Precise Detection on Cell-Cell Fusion by a Facile Molecular Beacon-Based Method.

Cell-cell fusion studies provide an experimental platform for evaluating disease progression and investigating cell infection. However, to realize sensitive and quantitative detection on cell-cell fusion is still a challenge. Herein, we report a facile molecular beacon (MB)-based method for precise detection on cell-cell fusion. By transfection of the spike protein (S protein) and enhanced green fluorescent protein (EGFP) in HEK 293 cells, the virus-mimicking fusogenic effector cells 293-S-EGFP cells were constructed to interact with target cells. Before mixing the effector cells with the target cells, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression in 293-S-EGFP cells was silenced, and the MB for GAPDH mRNA detection was delivered into the GAPDH silenced 293-S-EGFP cells. Once cell-cell fusion occurred, MB migrated from the GAPDH silenced effector cells to the target cells and hybridized with GAPDH mRNA in the target cells to induce fluorescence emission. The cell-cell fusion can be easily visualized and quantitated by fluorescence microscopy and flow cytometry. The fluorescence intensity is strongly dependent on the number of fused target cells. This MB-based method can easily identify the differences in the cell fusions for various target cells with different angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) expression levels, resulting in dramatically different fluorescence intensities in fused target cells. Our study provides a convenient and efficient quantitative detection approach to study cell-cell fusion.

The novel indomethacin derivative CZ-212-3 exerts antitumor effects on castration-resistant prostate cancer by degrading androgen receptor and its variants.

Androgen receptor (AR) serves as a main therapeutic target for prostate cancer (PCa). However, resistance to anti-androgen therapy (SAT) inevitably occurs. Indomethacin is a nonsteroidal anti-inflammatory drug that exhibits activity against prostate cancer. Recently, we designed and synthesized a series of new indomethacin derivatives (CZ compounds) via Pd (II)-catalyzed synthesis of substituted N-benzoylindole. In this study, we evaluated the antitumor effect of these novel indomethacin derivatives in castration-resistant prostate cancer (CRPC). Upon employing CCK-8 cell viability assays and colony formation assays, we found that these derivatives had high efficacy against CRPC tumor growth in vitro. Among these derivatives, CZ-212-3 exhibited the most potent efficacy against CRPC cell survival and on apoptosis induction. Mechanistically, CZ-212-3 significantly suppressed the expression of AR target gene networks by degrading AR and its variants. Consistently, CZ-212-3 significantly inhibited tumor growth in CRPC cell line-based xenograft and PDX models in vivo. Taken together, the data show that the indomethacin derivative CZ-212-3 significantly inhibited CRPC tumor growth by degrading AR and its variants and could be a promising agent for CRPC therapy.

A Novel Auto-Synthesis Dataset Approach for Fitting Recognition Using Prior Series Data.

To address power transmission line (PTL) traversing complex environments leading to data collection being difficult and costly, we propose a novel auto-synthesis dataset approach for fitting recognition using prior series data. The approach mainly includes three steps: (1) formulates synthesis rules by the prior series data; (2) renders 2D images based on the synthesis rules utilizing advanced virtual 3D techniques; (3) generates the synthetic dataset with images and annotations obtained by processing images using the OpenCV. The trained model using the synthetic dataset was tested by the real dataset (including images and annotations) with a mean average precision (mAP) of 0.98, verifying the feasibility and effectiveness of the proposed approach. The recognition accuracy by the test is comparable with training by real samples and the cost is greatly reduced to generate synthetic datasets. The proposed approach improves the efficiency of establishing a dataset, providing a training data basis for deep learning (DL) of fitting recognition.

Randomized, Double-Blinded, Placebo-Controlled Phase 2 Trial of an Inactivated Severe Acute Respiratory Syndrome Coronavirus 2 Vaccine in Healthy Adults.

BACKGROUND: We evaluated an inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine for immunogenicity and safety in adults aged 18-59 years. METHODS: In this randomized, double-blinded, controlled trial, healthy adults received a medium dose (MD) or a high dose (HD) of the vaccine at an interval of either 14 days or 28 days. Neutralizing antibody (NAb) and anti-S and anti-N antibodies were detected at different times, and adverse reactions were monitored for 28 days after full immunization. RESULTS: A total of 742 adults were enrolled in the immunogenicity and safety analysis. Among subjects in the 0, 14 procedure, the seroconversion rates of NAb in MD and HD groups were 89% and 96% with geometric mean titers (GMTs) of 23 and 30, respectively, at day 14 and 92% and 96% with GMTs of 19 and 21, respectively, at day 28 after immunization. Anti-S antibodies had GMTs of 1883 and 2370 in the MD group and 2295 and 2432 in the HD group. Anti-N antibodies had GMTs of 387 and 434 in the MD group and 342 and 380 in the HD group. Among subjects in the 0, 28 procedure, seroconversion rates for NAb at both doses were both 95% with GMTs of 19 at day 28 after immunization. Anti-S antibodies had GMTs of 937 and 929 for the MD and HD groups, and anti-N antibodies had GMTs of 570 and 494 for the MD and HD groups, respectively. No serious adverse events were observed during the study period. CONCLUSIONS: Adults vaccinated with inactivated SARS-CoV-2 vaccine had NAb as well as anti-S/N antibody and had a low rate of adverse reactions. CLINICAL TRIALS REGISTRATION: NCT04412538.

VE-cadherin N-glycosylation modified by N-acetylglucosaminyltransferase V regulates VE-cadherin-ß-catenin interaction and monocyte adhesion.

NEW FINDINGS: What is the central question of this study? Inflammation-induced monocyte adhesion is the initiator of most vascular diseases. The underlying mechanisms that mediate monocyte adhesion remain to be clarified fully. What is the main finding and its importance? N-acetylglucosaminyltransferase V (GnT-V)-mediated N-glycosylation of VE-cadherin regulates the dissociation of the VE-cadherin-ß-catenin complex to modulate monocyte adhesion, but GnT-V overexpression cannot rescue monocyte adhesion induced by interleukin-1ß. This study clarified the molecular mechanism of VE-cadherin in regulating the monocyte adhesion process. ABSTRACT: Monocyte adhesion is a crucial step in the initial stage of atherosclerosis, and dysfunction of VE-cadherin has been reported to be involved in this process. Our group previously found that VE-cadherin and its binding protein, ß-catenin, were modified by sialylation, and the levels of sialylation were decreased in pro-inflammatory cytokine-treated human umbilical vein EA.hy926 cells. In this study, we confirmed that the sugar chains of VE-cadherin were modified by N-acetylglucosaminyltransferase V (GnT-V). We showed that the levels of GnT-V and ß1,6-N-acetylglucosamine on the VE-cadherin were reduced in the presence of interleukin-1ß, whereas the level of monocyte transendothelial migration was increased. Moreover, the interaction between VE-cadherin and ß-catenin was increased, accompanied by an increased accumulation of degradative VE-cadherin and cytoplasmic ß-catenin, indicating impairment of cell-cell junctions after interleukin-1ß treatment. Furthermore, GnT-V short hairpin RNA and overexpression analysis confirmed that glycosylation of VE-cadherin was modified by GnT-V in EA.hy926 cells, which contributed to the monocyte-endothelial adhesion process. Taken together, these results suggest that the function of VE-cadherin in facilitating monocyte adhesion might result from the decreasing GnT-V expression and disorder of GnT-V-catalysed N-glycosylation. Our study clarified the molecular mechanism of VE-cadherin in regulation of the monocyte adhesion process and provided new insights into the post-transcriptional modifications of VE-cadherin.

Risk factors of gestational diabetes mellitus during assisted reproductive technology procedures.

To investigate risk factors of gestational diabetes mellitus (GDM) during assisted reproductive technology (ART) procedures. A total of 1022 patients were included in this retrospective cohort study from January 1, 2014 to August 31, 2017. While patients were divided into two groups: the non- GDM group and the GDM group. There was no significant difference in basal FSH, AFC, infertility years, gestational age, number of fetus, method of fertilization, and reason of infertility between the two groups. However, age, BMI, and fresh cycle were verified to be association with GDM by using logistic regression model. During the process of controlled ovarian hyperstimulation (COH), estradiol (E2) was significantly lower in the GDM group. The incidence of GDM was highest when E2 level less than 200 pg/mL of per oocyte. Our study showed maternal fundamental factors had greater impacts on subsequent GDM.

[UPLC quantitative fingerprint research on Gardeniae Fructus based on chemical pattern recognition technology].

Twenty-six batches of Gardeniae Fructus from different producing area were collected for the development of the fingerprint, and the main components of Gardeniae Fructus were identified by liquid chromatography-mass spectrometry. The producing areas of Gardeniae Fructus were distinguished by chemical pattern recognition technology, and the index components of Gardeniae Fructus were quantitated. An UPLC wavelength switching method was adopted, and the separation was carried out on a Waters Acquity UPLC HASS C_(18)(2.1 mm×100 mm, 1.7 µm) column using the mobile phase of acetonitrile-0.5% formic acid water for gradient elution. Principal component analysis(PCA) and orthogonal partial least square discriminant analysis(OPLS-DA) were used for the data ana-lysis. The results showed that the similarity of 26 batches of Gardeniae Fructus was more than 0.89, and ten common peaks were defined. Sixteen compounds including monoterpenes, iridoids and diterpenoids were identified by reference identification, literature comparison and high-resolution mass spectrometry data analysis. The distinguishment of origin of Gardeniae Fructus was realized by PCA and OPLS-DA analysis, and two quality differential markers were screened as geniposide and crocin Ⅰ. The contents of crocin Ⅰ, crocin Ⅱ and geniposide in Gardeniae Fructus from different places were different. These results will provide reference for the geographical origin traceability of Gardeniae Fructus.

Puzzle of Complete Fusion Suppression in Weakly Bound Nuclei: A Trojan Horse Effect?

Experimental studies of nuclear collisions involving light weakly bound nuclei show a systematic suppression of the complete fusion cross section by ∼30% with respect to the expectation for tightly bound nuclei, at energies above the Coulomb barrier. Although it is widely accepted that the phenomenon is related to the weak binding of these nuclei, the origin of this suppression is not fully understood. Here, we present a novel approach that provides the complete fusion for weakly bound nuclei and relates its suppression to the competition between the different mechanisms contributing to the reaction cross section. The method is applied to the ^{6,7}Li+^{209}Bi reactions, where we find that the suppression of complete fusion is mostly caused by the flux associated with nonelastic breakup modes, such as the partial capture of the projectile (incomplete fusion), whereas the elastic breakup mode is found to play a minor role. Finally, we demonstrate that the large α yields observed in these reactions can be naturally explained as a consequence of a Trojan Horse mechanism.

Unraveling the Reaction Mechanisms Leading to Partial Fusion of Weakly Bound Nuclei.

Collisions between complex nuclei may give rise to their total or partial fusion. The latter case is found experimentally to gain importance when one of the colliding nuclei is weakly bound. It has been commonly assumed that the partial fusion mechanism is a two-step process, whose first step is the dissociation of the weakly bound nucleus, followed by the capture of one of the fragments. To assess this interpretation, we present the first implementation of the three-body model of inclusive breakup proposed in the 1980s by Austern et al. [Phys. Rep. 154, 125 (1987)PRPLCM0370-157310.1016/0370-1573(87)90094-9] that accounts for both the direct, one-step, partial fusion and the two-step mechanism proceeding via the projectile continuum states. Contrary to the widely assumed picture, we find that, at least for the investigated cases, the partial fusion is largely dominated by the direct capture from the projectile ground state.

Stereodirecting Effect of C5-Carboxylate Substituents on the Glycosylation Stereochemistry of 3-Deoxy-d- manno-oct-2-ulosonic Acid (Kdo) Thioglycoside Donors: Stereoselective Synthesis of α- and ß-Kdo Glycosides.

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 ß-stereoselectivity, furnishing the corresponding ß-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 ß 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 ß-Kdo glycosidic bonds.

A strategy for designing voriconazole dosage regimens to prevent invasive pulmonary aspergillosis based on a cellular pharmacokinetics/pharmacodynamics model.

BACKGROUND: Invasive pulmonary aspergillosis (IPA) is a life-threatening disease in immunosuppressed patients. Voriconazole is commonly used to prevent and treat IPA in the clinic, but the optimal prophylactic antifungal regimen is unknown. The objective of this study was to clarify the mechanism underlying how voriconazole prevents IPA based on a target cellular pharmacokinetics/pharmacodynamics model, with the aim of identifying a way to design an optimal prophylactic antifungal regimen. METHODS: A nystatin assay was used to establish a target-cells model for A. fumigatus infection. An inhibitory effect sigmoid Emax model was developed to explore the cellular PK/PD breakpoint, and Monte Carlo simulation was used to design the prophylactic antifungal regimen. RESULTS: The intracellular activity of voriconazole in the target cells varied with its concentration, with the minimum inhibitory concentration (MIC) being an important determinant. For A. fumigatus strains AF293 and AF26, voriconazole decreased the intracellular inoculum by 0.79 and 0.84 lg cfu, respectively. The inhibitory effect sigmoid Emax model showed that 84.01% of the intracellular inoculum was suppressed by voriconazole within 24 h, and that a PK/PD value of 35.53 for the extracellular voriconazole concentration divided by MIC was associated with a 50% suppression of intracellular A. fumigatus. The Monte Carlo simulation results showed that the oral administration of at least 200 mg of voriconazole twice daily was yielded estimated the cumulative fraction of response value of 91.48%. Concentration of voriconazole in the pulmonary epithelial lining fluid and the plasma of > 17.77 and > 1.55 mg/L, respectively, would ensure the PK/PD > 35.53 for voriconazole against most isolates of A. fumigatus and may will be benefit to prevent IPA in clinical applications. CONCLUSIONS: This study used a target cellular pharmacokinetics/pharmacodynamics model to reveal a potential mechanism underlying how voriconazole prevents IPA and has provided a method for designing voriconazole prophylactic antifungal regimen in immunosuppressed patients.