Uneven impacts of COVID-19 on residents' utilization of urban parks: A case study of Guangzhou, China.

As COVID-19 increased people's dependency on urban parks for physical and psychological well-being, it also has uncertain impacts on park utilization. Understanding these impacts and how the pandemic has contributed to them is an issue that warrants urgent attention. We used multi-source spatio-temporal data to examine urban park use before and during COVID-19 in Guangzhou, China, and constructed a set of regression models to evaluate the associated factors. We found that COVID-19 has significantly reduced the overall utilization of urban parks while also exacerbating spatial unevenness. This was due to residents' limited movement distance, and the diminished role of urban transportation affecting the efficient citywide use of parks. Meanwhile, residents' increased demand for nearby parks amplified the importance of community parks, which exacerbated the consequences caused by the uneven distribution of park resources. We propose that city administrators improve the efficiency of existing parks and prioritize the adequate placement of community parks at urban fringes to improve access. Furthermore, cities with similar layouts as Guangzhou should plan for urban parks from a multi-perspective and consider the sub-city level differences to address unevenness during the current pandemic and in the future.

Intervertebral focal surgery for the treatment of non-contiguous multifocal spinal tuberculosis.

PURPOSE: The purpose of this study was to assess the clinical efficacy of intervertebral focal surgery by complete debridement, deformity correction, graft fusion, and internal fixation for patients with non-contiguous multifocal spinal tuberculosis. METHODS: A total of 29 cases with non-contiguous multifocal spinal tuberculosis admitted to the hospital from January 2000 to January 2007 were treated by intervertebral focal surgery. There were 63 foci in 29 cases, averaging 2.2 foci per case, and 146 affected vertebral bodies, averaging 2.3 vertebral bodies per focus. Three cases had one normal intervertebral disc between two foci, and the other 26 cases had two or more normal intervertebral discs between two foci. RESULTS: All cases were followed-up for an average of five years. The kyphosis showed a mean correction rate of 67.7% after surgery. A mean loss rate of correction of 8.2% was observed at the final follow-up. The levels of erythrocyte sedimentation rate and C-reactive protein returned to normal in 27 cases on average at 5.8 months and bone union could be observed at five months after surgery. Eleven cases with nerve damage recovered to E grade at the final follow-up. CONCLUSIONS: Intervertebral focal surgery by complete debridement, deformity correction, graft fusion, and internal fixation for patients with non-contiguous multifocal spinal tuberculosis was feasible and effective.

Effect of mutational inactivation of tyrosine kinase activity on BCR/ABL-induced abnormalities in cell growth and adhesion in human hematopoietic progenitors.

Chronic myelogenous leukemia (CML) results from transformation of a primitive hematopoietic cell by the BCR/ABL gene. The specific BCR/ABL signaling mechanisms responsible for transformation of primitive human hematopoietic cells are not well defined. Previous studies have suggested that constitutively activated tyrosine kinase activity plays an important role for in abnormal proliferation of CML progenitors but has not clearly defined its role in abnormal adhesion and migration. We established a human progenitor model of CML by ectopic expression of BCR/ABL in normal CD34+ cells using retrovirus-mediated gene transfer. CD34+ cells expressing BCR/ABL demonstrated several features characteristic of primary CML progenitors including increased proliferation in committed and primitive progenitor culture, reduced adhesion to fibronectin, and reduced chemotaxis to stroma-derived factor-1alpha. We expressed a kinase-inactive BCR/ABL gene to directly investigate the role of kinase activity in abnormal progenitor function. Abnormalities in proliferation were completely reversed, whereas defects in adhesion and migration were significantly improved but not completely reversed in cells expressing a kinase-inactive BCR/ABL. Furthermore, the BCR/ABL kinase inhibitor imatinib mesylate markedly inhibited proliferation of BCR/ABL-expressing progenitors but did not fully correct the adhesion and migration defects. Expression of BCR/ABL genes with deletions of either the COOH-terminal actin binding or proline-rich domains resulted in enhanced adhesion and chemotaxis compared with wild-type BCR/ABL but did not affect progenitor proliferation. We conclude that abnormal kinase activity is essential for abnormal proliferation and survival of CML progenitors but that abnormal adhesion and migration result from both kinase-dependent and -independent mechanisms.

Novel targeting of PEGylated liposomes for codelivery of TGF-ß1 siRNA and four antitubercular drugs to human macrophages for the treatment of mycobacterial infection: a quantitative proteomic study.

Tuberculosis (TB) is still a major public health issue in developing countries, and its chemotherapy is compromised by poor drug compliance and severe side effects. This study aimed to synthesize and characterize new multimodal PEGylated liposomes encapsulated with clinically commonly used anti-TB drugs with linkage to small interfering RNA (siRNA) against transforming growth factor-ß1 (TGF-ß1). The novel NP-siRNA liposomes could target THP-1-derived human macrophages that were the host cells of mycobacterium infection. The biological effects of the NP-siRNA liposomes were evaluated on cell cycle distribution, apoptosis, autophagy, and the gene silencing efficiency of TGF-ß1 siRNA in human macrophages. We also explored the proteomic responses to the newly synthesized NP-siRNA liposomes using the stable isotope labeling with amino acids in cell culture approach. The results showed that the multifunctional PEGylated liposomes were successfully synthesized and chemically characterized with a mean size of 265.1 nm. The novel NP-siRNA liposomes functionalized with the anti-TB drugs and TGF-ß1 siRNA were endocytosed efficiently by human macrophages as visualized by transmission electron microscopy and scanning electron microscopy. Furthermore, the liposomes showed a low cytotoxicity toward human macrophages. There was no significant effect on cell cycle distribution and apoptosis in THP-1-derived macrophages after drug exposure at concentrations ranging from 2.5 to 62.5 µg/mL. Notably, there was a 6.4-fold increase in the autophagy of human macrophages when treated with the NP-siRNA liposomes at 62.5 µg/mL. In addition, the TGF-ß1 and nuclear factor-κB expression levels were downregulated by the NP-siRNA liposomes in THP-1-derived macrophages. The Ingenuity Pathway Analysis data showed that there were over 40 signaling pathways involved in the proteomic responses to NP-siRNA liposome exposure in human macrophages, with 160 proteins mapped. The top five canonical signaling pathways were eukaryotic initiation factor 2 signaling, actin cytoskeleton signaling, remodeling of epithelial adherens junctions, epithelial adherens junction signaling, and Rho GDP-dissociation inhibitor signaling pathways. Collectively, the novel synthetic targeting liposomes represent a promising delivery system for anti-TB drugs to human macrophages with good selectivity and minimal cytotoxicity.

Pro-apoptotic and pro-autophagic effects of the Aurora kinase A inhibitor alisertib (MLN8237) on human osteosarcoma U-2 OS and MG-63 cells through the activation of mitochondria-mediated pathway and inhibition of p38 MAPK/PI3K/Akt/mTOR signaling pathway.

Osteosarcoma (OS) is the most common malignant bone tumor occurring mostly in children and adolescents between 10 and 20 years of age with poor response to current therapeutics. Alisertib (ALS, MLN8237) is a selective Aurora kinase A inhibitor that displays anticancer effects on several types of cancer. However, the role of ALS in the treatment of OS remains unknown. This study aimed to investigate the effects of ALS on the cell growth, apoptosis, autophagy, and epithelial to mesenchymal transition (EMT) and the underlying mechanisms in two human OS cell lines U-2 OS and MG-63. The results showed that ALS had potent growth inhibitory, pro-apoptotic, pro-autophagic, and EMT inhibitory effects on U-2 OS and MG-63 cells. ALS remarkably induced G2/M arrest and down-regulated the expression levels of cyclin-dependent kinases 1 and 2 and cyclin B1 in both U-2 OS and MG-63 cells. ALS markedly induced mitochondria-mediated apoptosis with a significant increase in the expression of key pro-apoptotic proteins and a decrease in main anti-apoptotic proteins. Furthermore, ALS promoted autophagic cell death via the inhibition of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) and p38 mitogen-activated protein kinase (p38 MAPK) signaling pathways, and activation of 5'-AMP-dependent kinase (AMPK) signaling pathway. Inducers or inhibitors of apoptosis or autophagy simultaneously altered ALS-induced apoptotic and autophagic death in both U-2 OS and MG-63 cells, suggesting a crosstalk between these two primary modes of programmed cell death. Moreover, ALS suppressed EMT-like phenotypes with a marked increase in the expression of E-cadherin but a decrease in N-cadherin in U-2 OS and MG-63 cells. ALS treatment also induced reactive oxygen species (ROS) generation but inhibited the expression levels of sirtuin 1 and nuclear factor-erythroid-2-related factor 2 (Nrf2) in both cell lines. Taken together, these findings show that ALS promotes apoptosis and autophagy but inhibits EMT via PI3K/Akt/mTOR, p38 MAPK, and AMPK signaling pathways with involvement of ROS- and sirtuin 1-associated pathways in U-2 OS and MG-63 cells. ALS is a promising anticancer agent in OS treatment and further studies are needed to confirm its efficacy and safety in OS chemotherapy.

Proteomic analysis of grape berry skin responding to sunlight exclusion.

The most obvious effect of sunlight exclusion from grape clusters is the inhibition of anthocyanin biosynthesis in the berry skin so that no color develops. Two-dimensional gel electrophoresis coupled with mass spectrometry was used to characterize the proteins isolated from berry skins that developed under sunlight exclusion versus those from sunlight-exposed berries. Among more than 1500 spots resolved in stained gels, the accumulation patterns of 96 spots differed significantly between sunlight-excluded berry skin and that of sunlight-exposed control berries. Seventy-two proteins, including 35 down-regulated and 37 up-regulated proteins, were identified and categorized. Proteins involved in photosynthesis and secondary metabolism, especially UDP-glucose:flavonoid 3-O-glucosyltransferase (UFGT), the key step for anthocyanin biosynthesis in grape berry skin, were accumulated less in the absence of sunlight. Several isoforms of heat shock proteins were also down-regulated. The proteins that were over-accumulated in sunlight-excluded berry skin were more often related to energy production, glycolysis, the tricarboxylic-acid cycle, protein synthesis and biogenesis of cellular components. Their putative role is discussed in terms of their relevance to sunlight exclusion processes.

Evaluation of the asynchronization and function of the left ventricle in patients with chronic pulmonary hypertension by velocity vector imaging.

BACKGROUND: Pulmonary hypertension (PH) is a set of pathophysiological syndromes characterized by increased pulmonary artery pressure and pulmonary vascular resistance, resulting in increased right ventricular afterload. The left and right ventricles interact through hemodynamics. What impact will PH have on synchronization and function of the left ventricle (LV)? The aim of this study was to evaluate the synchronization of the left ventricular wall motion and left ventricular function in patients with varying degrees of PH using velocity vector imaging (VVI) technology. METHODS: Sixty patients with chronic PH served as the experimental group, and 20 healthy volunteers served as the control group. According to the different degrees of pulmonary artery systolic pressure, the experimental group was divided into three groups: mild, moderate, and severe PH groups. The time to peak systolic longitudinal velocity (Tvl), the peak systolic longitudinal velocity (Vsl), the peak diastolic longitudinal velocity (Vel), the peak systolic longitudinal strain (Sl), and strain rate (SRl) in 18 segments were measured in each group. RESULTS: Tvl in the control group and each group with PH was reduced from basal to apical segment, and in control group Tvl in various segments of the same wall and in different walls showed no significant difference (P > 0.05). With increase in pulmonary artery pressure, Tvl values measured showed an increasing trend in groups with PH. In groups with PH, Vsl and Vel of each wall were reduced sequentially from basal to apical segments, showing gradient change; Vsl and Vel values measured showed a decreasing trend with increase in pulmonary artery pressure, in which the differences of Vel values measured in the control group and the mild PH group were statistically significant (P < 0.01), and the differences between other groups were statistically significant (P < 0.01). In groups with PH, Sl and SRl in basal segment and the middle segment of each wall were decreased; the difference between groups was statistically significant (P < 0.01). CONCLUSIONS: Asynchronization of the LV and decreased left ventricular function were present in patients with chronic PH; VVI technology can accurately evaluate left ventricular function in patients with PH, and indicators such as Tvl, Vsl, and Vel are valuable.

Persistence of malignant hematopoietic progenitors in chronic myelogenous leukemia patients in complete cytogenetic remission following imatinib mesylate treatment.

The BCR/ABL tyrosine kinase inhibitor imatinib mesylate (Gleevec, STI571; Novartis, Basel, Switzerland) has shown remarkable efficacy in the treatment of chronic myelogenous leukemia (CML), with a high proportion of patients achieving complete cytogenetic responses (CCRs). However, it is not clear whether remissions will be durable and whether imatinib mesylate can eliminate the malignant primitive progenitors in which the disease arises. We investigated whether residual BCR/ABL+ hematopoietic progenitors were present in patients who achieved CCRs with imatinib mesylate treatment. CD34+ progenitor cells were selected from bone marrow mononuclear cells (MNCs) and analyzed for the presence of the BCR/ABL fusion gene by fluorescence in situ hybridization (FISH). CD34+ cells were also plated in committed progenitor (colony-forming cell, or CFC) and primitive progenitor (long-term bone marrow culture-initiating cell, or LTCIC) cultures and resulting colonies analyzed for the presence of BCR/ABL+ cells by FISH. Using these assays, residual BCR/ABL+ progenitors were detected in all patients studied. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis demonstrated increased levels of BCR/ABL mRNA in CD34+ cells compared with total MNCs. Evaluation of samples collected at different time points demonstrated persistence of BCR/ABL+ progenitors despite continued treatment with imatinib mesylate. Our results indicate that inhibition of BCR/ABL tyrosine kinase activity by imatinib mesylate does not eliminate malignant primitive progenitors in CML patients. Patients in CCR with imatinib mesylate treatment need to be followed carefully to assess for risk of relapse.