Structure-Unit-Based Total Synthesis of (-)-Sinulochmodin C.

Herein we report a structure-unit-based asymmetric total synthesis of sinulochmodin C, a norcembranoid diterpenoid bearing a transannular strained ether bridge ß-keto tetrahydrofuran moiety. Our synthetic route features an intramolecular double Michael addition to construct stereospecifically the [7,6,5,5] tetracyclic skeleton, a vinylogous hydroxylation/oxidation procedure or a stereospecific epoxide opening/oxidation sequence to establish the γ-keto enone intermediate, a Lewis acid/Brønsted acid mediated transannular oxa-Michael addition to fuse the ß-keto tetrahydrofuran moiety, a Mukaiyama hydration/Pd-C hydrogenation to reverse the C1-configuration of the isopropenyl unit, and a bioinspired transformation of sinulochmodin C into scabrolide A.

Isocoumarins from the fermentation products of a plant entophytic fungus Penicillium oxalicum.

Three new isocoumarins, terrecoumarins A-C (1-3), together with six known isocoumarins (4-9) were isolated from the fermentation products of the fungus Penicillium oxalicum 0403. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. The anti-tobacco mosaic virus (anti-TMV) activities of 1-9 were evaluated. The results revealed that compound 1 showed high anti-TMV activity with inhibition rate 25.4 ± 3.5%. Other compounds also showed weak activity with inhibition rate in the range of 11.3-18.9%.

Low remnant cholesterol and the subsequent risk of new-onset atrial fibrillation: A prospective cohort study.

BACKGROUND: Atrial fibrillation (AF) is a common arrhythmia with high morbidity and mortality implications. Several studies have described a paradoxical inverse relationship between serum cholesterol and the risk of AF, but it remains unknown whether remnant cholesterol (RC) is associated with AF incidence. OBJECTIVE: This study aims to prospectively investigate the association between RC and AF. METHODS: A total of 392,783 participants free of AF at baseline from the UK Biobank were included for the analysis. Cox proportional hazards model, subgroup analysis, and sensitivity analyses were used to evaluate the independent association between RC levels and the risk of new-onset AF. Furthermore, we performed a discordance analysis by using the median cutoff points of low-density lipoprotein cholesterol (LDL-C) and RC. RESULTS: After a median follow-up of 12.8 years (interquartile range 12.0-13.6 years), a total of 23,558 participants experienced incident AF. Compared with the highest RC level, the lower RC level was associated with an increased risk of AF incidence (quartile 1 vs quartile 4: hazard ratio 1.396; 95% confidence interval [CI] 1.343-1.452). The results remained robust across a series of sensitivity analyses. In the discordance analyses, a significantly higher risk of AF was observed in participants with discordant low RC/high LDL-C levels than in those with concordant high RC/LDL-C levels. In the low LDL-C group, RC reduction even contributed to an additional 15.8% increased rate of incident AF (low RC/low LDL-C: hazard ratio 1.303; 95% CI 1.260-1.348 vs high RC/low LDL-C: hazard ratio 1.125; 95% CI 1.079-1.172). CONCLUSION: Low RC levels were associated with an increased risk of incident AF independent of traditional cardiovascular risk factors.

Bacteria-mediated resistance of neutrophil extracellular traps to enzymatic degradation drives the formation of dental calculi.

Dental calculi can cause gingival bleeding and periodontitis, yet the mechanism underlying the formation of such mineral build-ups, and in particular the role of the local microenvironment, are unclear. Here we show that the formation of dental calculi involves bacteria in local mature biofilms converting the DNA in neutrophil extracellular traps (NETs) from being degradable by the enzyme DNase I to being degradation resistant, promoting the nucleation and growth of apatite. DNase I inhibited NET-induced mineralization in vitro and ex vivo, yet plasma DNases were ineffective at inhibiting ectopic mineralization in the oral cavity in rodents. The topical application of the DNA-intercalating agent chloroquine in rodents fed with a dental calculogenic diet reverted NET DNA to its degradable form, inhibiting the formation of calculi. Our findings may motivate therapeutic strategies for the reduction of the prevalence of the deposition of bacteria-driven calculi in the oral cavity.

The association between tinnitus and risk of cardiovascular events and all-cause mortality: insight from the UK Biobank.

BACKGROUND: The potential influence of tinnitus on cardiovascular disease (CVD) and all-cause mortality has yet to be explored. We aim to examine the correlations between tinnitus and the risk of cardiovascular events and all-cause mortality. METHODS: We conducted a prospective cohort study utilising data from the UK Biobank. The presence of tinnitus was evaluated through a questionnaire. The primary outcome was defined as a composition of cardiovascular events, including myocardial infarction (MI), stroke, and mortality from CVD, as well as all-cause mortality. Cox proportional hazard models were employed to examine the associations between tinnitus and both the primary outcome and its individual components. Sensitivity analyses were conducted to evaluate the robustness of the primary analysis. RESULTS: A total of 140,146 participants were included in the study. The presence of tinnitus was found to be associated with a higher incident rate of the primary outcome (HR = 1.057, 95%CI: 1.017-1.099, p = 0.005), MI (HR = 1.139, 95%CI: 1.061-1.222, p < 0.001) and all-cause mortality (HR = 1.053, 95%CI: 1.003-1.105, p = 0.038) after adjusting for confounders. However, there was no significant association between tinnitus and stroke or mortality from CVD. Subgroup analysis revealed that the association between tinnitus and the primary outcome was significant in females, participants with abnormal BMI, and those without hearing difficulty, depression or anxiety. Sensitivity analyses yielded consistent results. CONCLUSION: The findings from this study contribute to the existing body of evidence suggesting an association between tinnitus and an increased risk of cardiovascular events and all-cause mortality.

Molecular Mechanisms Underlying the Effects of Bimin Kang Mixture on Allergic Rhinitis: Network Pharmacology and RNA Sequencing Analysis.

Background: Allergic rhinitis (AR) is a highly prevalent chronic inflammatory disease of the respiratory tract. Previous studies have demonstrated that Bimin Kang Mixture (BMK) is effective in alleviating AR symptoms and reducing the secretion of inflammatory factors and mucin; however, the precise mechanisms underlying these effects remain unclear. Methods: We built target networks for each medication component using a network pharmacology technique and used RNA-seq transcriptome analysis to screen differentially expressed genes (DEGs) for AR patients and control groups. The overlapping targets in the two groups were assessed using PPI networks, GO, and KEGG enrichment analyses. The binding ability of essential components to dock with hub target genes was investigated using molecular docking. Finally, we demonstrate how BMK can treat AR by regulating the NF-κB signaling pathway through animal experiments. Results: Effective targets from network pharmacology were combined with DEGs from RNA-seq, with 20 intersections as key target genes. The construction of the PPI network finally identified 5 hub target genes, and all hub target genes were in the NF-κB signaling pathway. Molecular docking suggests that citric acid, deoxyandrographolide, quercetin, luteolin, and kaempferol are structurally stable and can spontaneously attach to IL-1ß, CXCL2, CXCL8, CCL20, and PTGS2 receptors. Animal experiments have shown that BMK inhibits NF-κB transcription factor activation, reduces the expression of proinflammatory cytokines and chemokines IL-1ß, CXCL2, IL-8, and COX-2, and exerts anti-inflammatory and anti-allergic effects. Conclusion: BMK by regulating the NF-κB signaling pathway improves inflammatory cell infiltration, regulates mucosal immune balance, and reduces airway hypersensitivity. These findings provide theoretical support for the clinical efficacy of BMK for AR treatment.

Diabetes onset at an earlier age and high HbA1c levels as risk factors of diabetic retinopathy.

AIM: To assess the effect of age at diabetes onset and uncontrollable high HbA1c levels on the development of diabetic retinopathy (DR) among Chinese type 2 diabetes mellitus (DM) patients. METHODS: This was a cross-sectional survey of diabetic patients in Subei district, China. Data covering physical measurements, fasting blood-glucose (FBG), glycosylated hemoglobin (HbA1c), blood lipid, urinary albumin/creatinine ratio (UACR), ocular fundus examination, and diabetes treatment records were collected. An independent sample t-test were used to analyze differences. A Logistic regression analysis was applied to study the independent risk factors of DR. RESULTS: A total of 1282 patients with type 2 DM were enrolled, and 191 cases had DR (14.9%). The age at diabetes onset, education level, alcohol consumption, HbA1c level, UACR level, and hypoglycemic drugs were independent influencing factors for DR. The older the onset of diabetes, the less likely to develop DR (OR: 0.958, 95%CI: 0.942-0.975, P=0.000). Patients were then divided in terms of age at diabetes onset as follows: <50y, 50-59y, 60-69y, and ≥70y. Compared with diabetes onset age <50y, 50-59y (OR: 0.463, 95%CI: 0.306-0.699, P=0.000), 60-69y (OR: 0.329, 95%CI: 0.203-0.535, P=0.000) and ≥70y (OR: 0.232, 95%CI: 0.094-0.577, P=0.002) were at a lower risk of DR. The prevalence of DR was highest in patients with diabetes onset age <50y (29.5%, P<0.05). The HbA1c level (8.67±1.97)% and proportion of insulin injection (52.5%) in patients with diabetes onset <40y were higher than in patients with older diabetes onset age (P<0.05). CONCLUSION: Diabetes onset at an earlier age and uncontrollable high HbA1c level could be independent risk factors for DR.

Design, Synthesis, and Anticancer Activity of Novel Trimethoxyphenyl-Derived Chalcone-Benzimidazolium Salts.

A series of novel trimethoxyphenyl-derived chalcone-benzimidazolium salts were synthesized. The biological properties of the compounds were screened in vitro against five different human tumor cell lines. The results suggest that the 5,6-dimethyl-benzimidazole or 2-methyl-benzimidazole ring as well as the 2-naphthylmethyl, 4-methylbenzyl, or 2-naphthylacyl substituent at position-3 of the benzimidazole ring was important to the cytotoxic activity. Notably, (E)-5,6-dimethyl-3-(naphthalen-2-ylmethyl)-1-(3-(4-(3-(3,4,5-trimethoxyphenyl)acryloyl)phenoxy)propyl)-1H-benzo[d]imidazol-3-ium bromide (7f) was more selective to HL-60, MCF-7, and SW-480 cell lines with IC50 values 8.0-, 11.1-, and 5.8-fold lower than DDP. Studies of the antitumor mechanism of action showed that compound 7f could induce cell-cycle G1 phase arrest and apoptosis in SMMC-7721 cells.

Pigment epithelium-derived factor/vascular endothelial growth factor ratio for early prediction of preeclampsia: A prospective multicenter study in China.

BACKGROUND: Imbalance of circulating factors related to angiogenesis plays a central role in the pathogenesis of preeclampsia (PE). OBJECTIVE: The aim of this study was to discover and validate a cutoff value of pigment epithelium-derived factor (PEDF)/vascular endothelial growth factor (VEGF) ratio for early prediction of PE before 20 weeks of gestation. STUDY DESIGN: This prospective multicenter study was performed in mainland China, and was divided into 3 phases to discover, develop, and validate a cutoff value of PEDF/VEGF ratio that could predict PE prior to diagnosis in pregnant women at high risk of PE (12 weeks 0 days to 19 weeks 6 days of gestation). We estimated PEDF/VEGF ratio at 5 visits: from visit 0 (baseline) to the postpartum visit. RESULTS: In the discovery phase (200 women), we found that antiangiogenic PEDF was higher and angiogenic VEGF was lower in the PE group than in the control group before 20 weeks of gestation. In the development phase (650 women), we found that a cutoff value of 800 for PEDF/VEGF ratio demonstrated a preferably predictive value. Subsequently, in the validation phase (additional 900 women), we found that the negative predictive value of PEDF/VEGF ratio ≤800 at the visit 1 was 98.6% (95% CI, 97.3-99.4), at the visit 2 was 96.9% (95% CI, 95.1-98.1) and at the visit 3 was 95.1% (95% CI, 93.0-96.7). ORs were 4.40, 6.27, and 5.73, respectively. CONCLUSIONS: PEDF/VEGF ratio ≤800 may have some predictive value for early diagnosis of PE. Further multicenter studies with larger sample sizes are necessary to confirm our findings.

Characterization of the metallo-dependent amidohydrolases responsible for "auxiliary" leucinyl removal in the biosynthesis of 2,2'-bipyridine antibiotics.

2,2'-Bipyridine (2,2'-BiPy) is an attractive core structure present in a number of biologically active natural products, including the structurally related antibiotics caerulomycins (CAEs) and collismycins (COLs). Their biosynthetic pathways share a similar key 2,2'-BiPy-l-leucine intermediate, which is desulfurated or sulfurated at C5, arises from a polyketide synthase/nonribosomal peptide synthetase hybrid assembly line. Focusing on the common off-line modification steps, we here report that the removal of the "auxiliary" l-leucine residue relies on the metallo-dependent amidohydrolase activity of CaeD or ColD. This activity leads to the production of similar 2,2'-BiPy carboxylate products that then receive an oxime functionality that is characteristic for both CAEs and COLs. Unlike many metallo-dependent amidohydrolase superfamily proteins that have been previously reported, these proteins (particularly CaeD) exhibited a strong zinc ion-binding capacity that was proven by site-specific mutagenesis studies to be essential to proteolytic activity. The kinetics of the conversions that respectively involve CaeD and ColD were analyzed, showing the differences in the efficiency and substrate specificity of these two proteins. These findings would generate interest in the metallo-dependent amidohydrolase superfamily proteins that are involved in the biosynthesis of bioactive natural products.

[Effect of hirudin on random skin flap survival in rats].

OBJECTIVE: To investigate the effect of Hirudin on random skin flap survival in rats. METHODS: 24 SD rats were randomly divided into control group and experimental group. The "McFarlane flap (3 cm x 9 cm)" rat models were established on the rat dorsum. 3 ml Hirudin (30 ATU) was injected into the flap in the experimental group, while 3 ml saline in the control group. The injection was performed for 7 days. The flap survival area in the two groups was measured. The tissue samples were taken from proximal (I), middle (II) and distal (III) portions of flaps for histologic study. The VEGF and bFGF expression was also detected with immunohistochemistry method. RESULTS: 7 days after operation, the flap survival rate was (69.52 +/- 3.23)% in the experimental group, while (50.36 +/- 2.37)% in control group, showing a significant difference between the two groups (P < 0. 01). In the middle portion, tissue edema and infiltration of neutrophils in experimental group was markedly slighter than that in control group. The VEGF and bFGF expression and neovascularization was enhanced markedly in experimental group. CONCLUSIONS: Hirudin can increase the survival of random pattern skin flaps. It may increase the VEGF, bFGF expression through a series of complex regulatory pathway. Then flap neovascularization is promoted and the flap blood supply is increased.

[Application of dorsal pentagonal flap for reconstruction of the web space in congenital syndactyly].

OBJECTIVE: To investigate the therapeutic effect of dorsal pentagonal flap for reconstruction of the web space in congenital syndactyly. METHODS: From October 2007 to August 2009, 10 patients with congenital syndactyly were treated with dorsal pentagonal flap for web space reconstruction. During the follow-up period, the patients underwent finger functional assessment and web space appearance examination. The satisfactory rate of patients was also investigated. RESULTS: 10 patients with 17 reconstructed web spaces were followed up for 4-25 months (median, 15 months). Normal passive flexion and extension of fingers were achieved with good cosmetic result at web space. The abduction angle of fingers ranged from 30 degrees to 45 degrees. No web creep occurred and no secondary procedures were required. All the parents of the patients were satisfied with the results. CONCLUSIONS: Web space reconstruction with dorsal pentagonal flap is easily performed with reliable blood supply and low re-operated rate. The cosmetic and functional result is satisfactory.