A Planar-Structured Dinuclear Cobalt(II) Complex with Indirect Synergy for Photocatalytic CO2-to-CO Conversion.

Dinuclear metal synergistic catalysis (DMSC) has been proved an effective approach to enhance catalytic efficiency in photocatalytic CO2 reduction reaction, while it remains challenge to design dinuclear metal complexes that can show DMSC effect. The main reason is that the influence of the microenvironment around dinuclear metal centres on catalytic activity has not been well recognized and revealed. Herein, we report a dinuclear cobalt complex featuring a planar structure, which displays outstanding catalytic efficiency for photochemical CO2-to-CO conversion. The turnover number (TON) and turnover frequency (TOF) values reach as high as 14457 and 0.40 s-1 respectively, 8.6 times higher than those of the corresponding mononuclear cobalt complex. Control experiments and theoretical calculations revealed that the enhanced catalytic efficiency of the dinuclear cobalt complex is due to the indirect DMSC effect between two CoII ions, energetically feasible one step two-electron transfer process by Co2 I,I intermediate to afford Co2 II,II(CO2 2-) intermediate and fast mass transfer closely related with the planar structure.

Modulating the Microenvironments of Robust Metal Hydrogen-Bonded Organic Frameworks for Boosting Photocatalytic Hydrogen Evolution.

Hydrogen-bonded organic frameworks (HOFs) are outstanding candidates for photocatalytic hydrogen evolution. However, most of reported HOFs suffer from poor stability and photocatalytic activity in the absence of Pt cocatalyst. Herein, a series of metal HOFs (Co2-HOF-X, X=COOMe, Br, tBu and OMe) have been rationally constructed based on dinuclear cobalt complexes, which exhibit exceptional stability in the presence of strong acid (12 M HCl) and strong base (5 M NaOH) for at least 10 days. More impressively, by varying the -X groups of the dinuclear cobalt complexes, the microenvironment of Co2-HOF-X can be modulated, giving rise to obviously different photocatalytic H2 production rates, following the -X group sequence of -COOMe>-Br>-tBu>-OMe. The optimized Co2-HOF-COOMe shows H2 generation rate up to 12.8 mmol g-1 h-1 in the absence of any additional noble-metal photosensitizers and cocatalysts, which is superior to most reported Pt-assisted photocatalytic systems. Experiments and theoretical calculations reveal that the -X groups grafted on Co2-HOF-X possess different electron-withdrawing ability, thus regulating the electronic structures of Co catalytic centres and proton activation barrier for H2 production, and leading to the distinctly different photocatalytic activity.

Paraneoplastic neurological syndrome with positive anti-Hu and anti-Yo antibodies: A case report.

BACKGROUND: Paraneoplastic neurological syndrome (PNS) is a rare complication in patients with cancer. PNS can affect the central, peripheral, autonomic nervous system, neuromuscular junction, or muscles and cause various neurological symptoms. Anti-Yo antibody-positive neurological paraneoplasms and anti-Hu antibody-positive neurological paraneoplasms are common, but coexistence of both types has not been described in the literature. CASE SUMMARY: Here we present a rare case of paraneoplastic neuropathy occurring in both breast and lung cancers. A 55-year-old woman was admitted to our hospital with unsteadiness while walking. The patient had a history of breast cancer two years previously. Chest computed tomography revealed a 4.6 cm × 3.6 cm mass in the right lung, which was diagnosed as small-cell lung cancer (SCLC). Blood test was positive for anti-Yo antibodies, and the cerebrospinal fluid was positive for both anti-Yo and anti-Hu antibodies, and the neurological symptoms were considered to be related to the paraneoplasm. The patient was treated with a course of intravenous immunoglobulin, without noticeable improvement. After being discharged from hospital, the patient underwent regular chemotherapy for SCLC and periodic reviews. The patient's neurological symptoms continued to deteriorate at the follow-up visit in April 2021. CONCLUSION: This case suggests the possibility of two types of tumors appearing simultaneously with two paraneoplastic antibodies. The clinical appearance of two or more paraneoplastic tumors requires additional attention.

M2-Like Microglia Polarization Attenuates Neuropathic Pain Associated with Alzheimer's Disease.

Many Alzheimer's disease (AD) patients suffer from persistent neuropathic pain (NP), which is mediated, at least partially, but microglia. Nevertheless, the exact underlying mechanism is unknown. Moreover, a clinically translatable approach through modulating microglia for treating AD-associated NP is not available. Here, in a doxycycline-induced mouse model (rTg4510) for AD, we showed development of NP. We found that the total number of microglia in the CA3 region was not increased, but polarized to pro-inflammatory M1-like phenotype, with concomitant increases in production and secretion of pro-inflammatory cytokines. To examine whether this microglia polarization plays an essential role in the AD-associated NP, we generated an adeno-associated virus (AAV) serotype PHP.B (capable of crossing the blood-brain barrier) carrying shRNA for DNA methyltransferase 1 (DNMT1) under a microglia-specific TMEM119 promoter (AAV-pTMEM119-shDNMT1), which specifically targeted microglia and induced a M2-like polarization in vitro and in vivo in doxycycline-treated rTg4510 mice. Intravenous infusion of AAV-pTMEM119-shDNMT1 induced M2-polarization of microglia and attenuated both AD-associated behavior impairment but also NP in the doxycycline-treated rTg4510 mice. Thus, our data suggest that AD-associated NP may be treated through M2-polarization of microglia.

Diabetes-Induced H3K9 Hyperacetylation Promotes Development of Alzheimer's Disease Through CDK5.

The connection between diabetes and Alzheimer's disease (AD) is not fully determined. Hyperphosphorylation of tau protein is mediated by binding and stabilization of truncated p25 with cyclin-dependent kinase-5 (CDK5) in AD. We recently showed that diabetes-associated hyperglycemia increased the CDK5 levels to promote development of AD. Here, we examined the underlying mechanisms. Hyperglycemia and glucose intolerance were induced in rats that had received a low dose of streptozotocin (STZ) and a high fat diet (HFD). Compared to the control rats that received no STZ and normal diet-fed, the STZ + HFD rats exhibited poorer performance in the behavioral test and showed hyperacetylation of H3K9 histone on CDK5 promoter, likely resulting from upregulation of a histone acetyltransferase, GCN5. Inhibition of acetylation of H3K9 histone by a specific GCN5 inhibitor, MB3, attenuated activation of CDK5, resulting in decreased tau phosphorylation in rat brain and improved performance of the rats in the behavior test. Thus, these data suggest that diabetes may promote future development of AD through hyperacetylation of H3K9 histone on CDK5 promoter.

miR-15a regulates oxygen glucose deprivation/reperfusion (OGD/R)-induced neuronal injury by targeting BDNF.

Multiple microRNAs (miRs) have also been implicated in ischemic brain injury. This research intended to probe the regulatory function and the mechanism of miR-15a on the ischemic brain injury induced by oxygen-glucose deprivation/reoxygenation (OGD/R) in neurons of rats. The OGD/R model was established with the cortical neurons separated from rats. After transfection with miR-15a mimic negative control (NC), miR-15a mimic, miR-15a inhibitor NC and miR-15a inhibitor, the OGD/R-induced apoptosis were detected. Using bioinformatic softwares including TargetScan, miRanda, and miRWalk to predict the underlying targets of miR-15a, and the binding of miR-15a with brain-derived neurotrophic factor (BDNF) were validated with double-fluorescein reporter assay system. The expression levels of BDNF mRNA and protein were detected with qRT-PCR and western blot. The effect of miR-15a on PI3K/AKT pathway in neurons submitted to OGD/R was also investigated. The findings showed that miR-15a may mediate the apoptosis of neurons submitted to OGD/R, and lower expression of Bcl-2 and higher expression of Bax and cleaved caspase-3 were observed. BDNF was screened as the candidate target, and the direct binding of miR-15a with 3'-UTR of BDNF were verified. Further research showed that miR-15a downregulated the expression of BDNF mRNA and protein, thus exerted negative regulatory effect on the OGD/R injury. PI3K/AKT pathway may be related to the regulatory effect of miR-15a. Our findings contribute to uncovering novel pathogenesis for ischemic brain injury.

Elevated serum macrophage migration inhibitory factor levels correlate with benign paroxysmal positional vertigo and recurrence events.

Objective: We aimed to assess the possible relations between serum levels of macrophage migration inhibitory factor (MIF), a central cytokine of the innate immunity and inflammatory response, and benign paroxysmal positional vertigo (BPPV) risk and BPPV recurrence events.Methods: In the present study, 154 patients with BPPV, and 100 age-and sex-matched control subjects were enrolled in the study. All the patients and controls underwent a complete audio-vestibular test battery including the Dix-Hallpike maneuver and supine roll test. In the BPPV group, measurements of MIF levels were repeated 1 month after the vertigo attack. The patients were also divided into the recurrence group and the nonrecurrence group in the 1-year follow-up.Results: The serum levels of MIF in patients with BPPV were higher than in those controls (13.9[interquartile range {IQR}, 8.9-18.4] ng/ml vs. 9.8[7.8-11.8]; P<0.001). As a continuous variable, MIF was associated with increased risk of BPPV (odds ratio [OR] 1.21, 95% confidence interval [CI]: 1.11-1.39; P=0.004) in multiple regression analyses. Recurrent attacks of BPPV were reported in 35 patients, and those patients had higher levels of MIF than those patients were not recurrence (18.0[IQR, 13.6-22.2] ng/ml vs. 12.6[9.3-16.8] ng/ml). In multivariate models comparing the second (Q2), third (Q3) and fourth(Q4) quartiles against the first (Q1) quartile of MIF, levels of MIF in Q4 were associated with recurrent BPPV, and the odds were increased by approximately 305% (OR = 4.05; 95%CI: 1.65-15.44; P=0.009).Conclusions: Elevated MIF is positively correlated with BPPV risk and BPPV recurrence events, requiring further efforts to clarify the exact mechanism.

Epigenetic Control of CDK5 Promoter Regulates Diabetes-Associated Development of Alzheimer's Disease.

Cyclin-dependent kinase-5 (CDK5) is activated by p35 and then binds to both p35 and its truncated form p25 to promote hyperphosphorylation of tau protein, thereby facilitating the pathological progression of Alzheimer's disease (AD). However, it is unknown whether a patient's diabetic status promotes the later onset of AD in a CDK5-dependent manner. Here, we induced pro-diabetic insulin resistance and glucose intolerance in rats using a combined high fat and high glucose diet. Compared to normal diet-fed rats, these pro-diabetic rats exhibited poorer behavioral performance in the Morris water maze test and the novel object recognition test. Increased phosphorylation of tau protein was detected in the hippocampal CA1 region of the rat brain, suggesting neurodegeneration. Moreover, CDK5 transcriptional activity was significantly increased in the HFGD-rat brain, likely resulting from an increase in acetylation and a decrease in methylation of the CDK5 promoter. Together, these data suggest that epigenetic control of the CDK5 promoter by acetylation and methylation may regulate the diabetes-associated development of AD.

The Efficacy and Safety of Granulocyte Colony-Stimulating Factor for Patients with Stroke.

BACKGROUND: Granulocyte colony-stimulating factor (G-CSF) has been shown to reduce lesion volume and improve functional outcome in experimental stroke models. However, whether G-CSF plays a role currently in patients with stroke remains uncertain. Our study aimed at examining the efficacy and safety of G-CSF in patients with acute ischemic stroke. METHODS: A comprehensive search was conducted in 5 online databases up to April 2014, and 10 studies with 711 patients met the criteria. RESULTS: The results showed that G-CSF was beneficial in improving the National Institutes of Health Stroke Scale (standardized mean difference [SMD], .43; 95% confidence interval [CI], .03-.82; P = .04) and modified Rankin Scale (mRS) scores (SMD, .72; 95% CI, .51-.93; P = .01), and elevating CD34(+) count (P < .001). No treatment effects were found in Barthel Index scores (SMD, -.13; 95% CI, -.61 to .35; P = .59), serious adverse events (relative ratio [RR], 1.12; 95% CI, .91-1.38; P = .28), or the death of serious adverse events (RR, 1.25; 95% CI, .82-1.91; P = .30) between groups at day 90. Adverse effect on vascular complications was not detected to be increased although G-CSF produced a marked elevation in the total leukocyte count (SMD, 3.52; 95% CI, 2.54-4.49; P < .001). CONCLUSIONS: In conclusion, G-CSF is effective at mobilizing bone marrow-derived CD34(+) stem cells to the peripheral blood. It also seems to improve the National Institutes of Health Stroke Scale and mRS scores. The administration of G-CSF appears to be safe and well tolerated. Further studies need to be done on a large sample to verify or fully characterize the results.

Association between the MMP-9-1562 C>T polymorphism and the risk of stroke: a meta-analysis.

Matrix metalloproteinase (MMP)-9 so far is identified as extremely large and complicated MMP family member. Recently, dozens of studies have explored the association between a promoter polymorphism (-1562 C>T) in MMP-9 and stroke susceptibility. However, the conclusions of these studies still remain equivocal. Therefore, our current meta-analysis was conducted to investigate whether or not the MMP-9 promoter polymorphism is related to the risk of stroke. Electronic databases (PubMed, EMBASE, Web of Science, Cochrane Library and the Chinese Biomedical Literature Database) were searched to obtain all the available studies investigating this polymorphism and stroke from inception to October 2013. Overall and subgroup analyses were rigorously conducted after data extraction. Pooled odds ratio (OR) corresponding to 95 % confidence interval (CI) were estimated. The statistical analysis was performed using Review Manager 5.2. Totally, seven studies involving 1,624 cases and 1,525 controls were identified. The overall results suggested that there was no association of the C-1562T variant on stroke risk under the T allele versus C allele [OR T vs. C 0.98, 95 % CI (0.84, 1.15), P = 0.84], the dominant model [OR TT+TC vs. CC 0.95, 95 % CI (0.81, 1.13), P = 0.59], the recessive model [OR TT vs. TC+CC 1.55, 95 % CI (0.86, 2.81), P = 0.15], the homozygote comparison [OR TT vs. CC 1.48, 95 % CI (0.82, 2.68), P = 0.20] and the heterozygote comparison [OR TC vs. CC 0.93, 95 % CI (0.78, 1.10), P = 0.38]. In the subgroup analyses by ethnicity, age, stroke type and source of controls, no significant relations were observed in any genetic models. Our results indicated that MMP-9-1562 C>T polymorphism was not a risk factor for stroke. Further studies should focus on gene-gene and gene-environment interactions, and provide a more convincing explanation for this association.