Epidemiological features of coronavirus disease 2019 in children: a meta-analysis.

OBJECTIVE: Many studies have been published recently on the characteristics of the clinical manifestations of COVID-19 in children. The quality scores of literature are different, and the incidence of clinical manifestations and laboratory tests results vary greatly. Therefore, a systematic retrospective meta-analysis is needed to determine the incidence of the clinical manifestations of COVID-19 in children. MATERIALS AND METHODS: Data from databases, such as PubMed, Web of science, EMBASE, Johns Hopkins University, and Chinese databases were analysed from January 31, 2020 to October 20, 2020. High-quality articles were selected for analysis based on a quality standard score. A meta-analysis of random effects was used to determine the prevalence of comorbidities and subgroup meta-analysis to examine the changes in the estimated prevalence in different subgroups. RESULTS: Seventy-one articles involving 11,671 children were included in the study. The incidence of fever, respiratory symptoms, gastrointestinal symptoms, asymptomatic patients, nervous system symptoms, and chest tightness was 55.8%, 56.8%, 14.4%, 21.1%, 6.7%, and 6.1%, respectively. The incidence of multisystem inflammatory syndrome was 6.2%. Laboratory examination results showed that lymphocytes decreased in 12% and leukocytes decreased in 8.8% of patients, whereas white blood cells increased in 7.8% of patients. Imaging showed abnormalities in 66.5%, and ground-glass opacities were observed in 36.9% patients. Epidemiological history was present in 85.2% cases; severe disease rate was 3.33%. The mortality rate was 0.28%. CONCLUSIONS: The clinical symptoms of COVID-19 in children are mild, and laboratory indicators and imaging manifestations are atypical. While screening children for COVID-19, in addition to assessing patients for symptoms as the first step of screening, the epidemiological history of patients should be obtained.

SD0006 promotes nucleus pulposus cell proliferation via the p38MAPK/HDAC4 pathway.

OBJECTIVE: p38 mitogen-activated protein kinase (p38MAPK) is a critical negative regulator for nucleus pulposus (NP) cell metabolism contributing to intervertebral disc degeneration (IDD). Histone deacetylase 4 (HDAC4) has the ability to mediate cell proliferation and is affected by p38MAPK. It is unclear whether the p38 MAPK inhibitor SD0006 (SD) can regulate IDD. Our study aims to explore the effect of SD in the progression of IDD, as well as its potential mechanism. PATIENTS AND METHODS: NP cells isolating from mild degenerated NP tissues were cultured, and IL-1ß or Asiatic acid (AA) was used to activate p38MAPK and accelerate the NP cell degradation. Then, SD was used to reject the p38MAPK activation. After that, the levels of phosphorylated p38MAPK (p-p38), HDAC4, proliferating cell nuclear antigen (PCNA), inflammatory factor, proliferative cell rate, and cell cycle were determined by Western blot, RT-PCR, flow cytometry, and immunofluorescence, respectively. RESULTS: The results showed that the activation of p38MAPK by IL-1ß and AA decreased the HDAC4 expression, affected the collagen-Ⅱ expression, upregulated the TNF-α, IL-6, MMP-3, and ADAMTS mRNA levels, and prevent the NP cell proliferation by mediating cell cycles. However, the application of SD alleviated the negative effect of p-p38 by upregulating HDAC4, anti-inflammation, and promoting cell proliferation, while the blocking of HDAC4 expression partly abolished the effect of SD. CONCLUSIONS: SD can prevent NP cell degeneration by promoting cell proliferation and suppressing inflammation via p38MAPK/HDAC4 pathway.

Low expression of miR-1 promotes osteogenic repair of bone marrow mesenchymal stem cells by targeting TLR1.

OBJECTIVE: Bone marrow mesenchymal stem cells (BMSCs) promote bone tissue repair. MiR-1 regulates myogenic and osteogenic differentiation of human adipose tissue stem cells. However, miR-1's effect on BMSCs osteogenesis is unclear. MATERIALS AND METHODS: Rat BMSCs were isolated and divided into control group, miR-1 group, and si-miR-1 group respectively transfected with miR-1 plasmid and miR-1 siRNA followed by analysis of cell proliferation by MTT assay and Caspase 3 activity. The expression of osteogenic genes Runx2 and OPN was measured by Real Time-PCR. Healthy male Sprague-Dawley rats were separated into fracture group, NC group, and si-miR-1 group followed by analysis of bone mineral density, miR-1 level by Real Time-PCR, type I collagen, and BMP-2 by enzyme-linked immunosorbent assay (ELISA), and TLR1 expression by Western blot. RESULTS: Transfection of miR-1 siRNA into BMSCs significantly downregulated miR-1 expression, promoted BMSCs cell proliferation, inhibited Caspase 3 activity, as well as promoted osteogenic genes Runx2 and OPN expression and decreased TLR1 expression (p<0.05). The upregulation of miR-1 expression significantly reversed the above changes. TLR1 is a target of miR-1. Downregulation of miR-1 expression in BMSCs of fractured rats significantly increased bone density and ALP activity, promoted type I collagen and BMP-2 expression, and decreased TLR1 expression (p<0.05). CONCLUSIONS: The downregulation of miR-1 promotes BMSCs osteogenic differentiation via targeting TLR1, which promotes osteogenic differentiation and bone healing.

A theoretical study of Ar8+-acetylene collisions at 1.2 MeV: Ionization and dissociation dynamics.

We theoretically study Ar8+-induced dissociation of C2H2 molecule at 1.2 MeV using the time-dependent density-functional theory non-adiabatically coupled to nuclear dynamics. We find that molecular dissociation depends strongly on the ionization at the initial stage and the collision configuration. A detailed analysis shows a correspondence between the charge state of [C2H2]q+ and the final fragments. A remarkable impact parameter effect provides deep insights of bond breakup and electronic transport. We analyze two typical sequential dissociation channels reported in experiments by tracking structural and electronic dynamics in real time. Our results provide better understanding of experiments. Moreover, the comparison between various exchange-correlation functionals reveals that electrons' correlation and self-interaction do not significantly impact the initial ionization and fragment distribution in the present study.

An animal model of reconstruction of single femoral tunnel with single bone bi-quadruple ACL and internal fixation.

We introduced several variables in an animal model of anterior cruciate ligament (ACL) reconstruction to determine the best parameters for surgery in humans. We divided 130 LYD pigs into two groups depending on whether the femoral tunnel goes through the medial tibial tunnel or through the medial fossa of the knee joint. Each subgroup was further divided. Four weeks after surgery the knee specimens were examined for passive flexion and extension test. No group showed a creep effect. In the biomechanical tests, we recorded maximal strength, maximum load, and stiffness parameters. The 100° + 1.0 mm, 1.5 mm, and 2.0 mm positions of the tibial tunnel group, and 10.5 (1.5) + 1.0 mm, 1.5 mm, and 2.0 mm positions of the knee joint cavity group had better biomechanical effects, histocompatibility and revascularization in ACL reconstruction. Overall, these results demonstrated significant differences in the effectiveness of ACL reconstruction based on several surgical parameters, which should contribute to establishing a gold standard for ACL surgery in patients.

Effects of epoxyeicosatrienoic acids (EETs) on retinal macular degeneration in rat models.

OBJECTIVE: Here we use a rat model to investigate the effects of epoxyeicosatrienoic acids (EETs) on retinal macular degeneration along with pathological and physiological mechanisms of the disease. MATERIALS AND METHODS: Six choroidal neovascularization (CNV) rats were created with a 532 nm laser and received intravitreal injections of EETs in both eyes. On day 1, 3, 7 and 14 after photocoagulation, the thickness and area of CNV were measured with HE staining and choroidal flat mounts. COX-2 and VEGF levels in CNV were detected by immunohistochemistry method. Protein and mRNA expression were studied by Western blotting and RT-PCR. RESULTS: 14 days after photocoagulation, CNV thickness and area were significantly reduced (p<0.01) in the treatment group compared with the control group. COX-2 and VEGF had high expression in vascular endothelial cells and stromal cells of CNV. Peak expression of COX-2 and VEGF was significantly higher (p<0.01) in the treatment group than in the control group. 7 days after photocoagulation, VEGF protein and mRNA expression were significantly lower (p<0.05) in the treatment group than in the control group, whereas COX-2 mRNA showed no significant difference (p>0.05). FFA found that CNV fluorescein leakage area was significantly reduced (p<0.05) in the treatment group than in the control group. 14 days after photocoagulation, neovascularization area was significantly smaller (p<0.05) in the treatment group than in the control group. Vitreous EETs levels in the treatment group were significantly higher than in the control group. Compared with the control group, the celecoxib treatment group had significantly increased vitreous EETs (p<0.05). CONCLUSIONS: Intravitreal injection of celecoxib could suppress the thickness and area of laser-induced macular degeneration CNV. It also improved the vitreous EETs levels in CNV model rats. COX-2 expression was upregulated in the early generation of laser-induced CNV, which may play an important role in regulating expression of VEGF.

Long intergenic non-coding RNA APOC1P1-3 inhibits apoptosis by decreasing α-tubulin acetylation in breast cancer.

Increasing evidence indicates that long non-coding RNAs (lncRNAs) act as important regulatory factors in tumor progression. However, their roles in breast cancer remain largely unknown. In present studies, we identified aberrantly expressed long intergenic non-coding RNA APOC1P1-3 (lincRNA-APOC1P1-3) in breast cancer by microarray, verified it by quantitative real-time PCR, and assessed methylation status in the promoter region by pyrosequencing. We also investigated the biological functions with plasmid transfection and siRNA silencing experiments, and further explored their mechanisms by RNA pull-down and RNA immunoprecipitation to identify binding proteins. We found that 224 lncRNAs were upregulated in breast cancer, whereas 324 were downregulated. The lincRNA-APOC1P1-3 was overexpressed in breast cancer, which was related to tumor size and hypomethylation in its promoter region. We also found that APOC1P1-3 could directly bind to tubulin to decrease α-tubulin acetylation, to inactivate caspase-3, and to inhibit apoptosis. This study demonstrates that overexpression of APOC1P1-3 can inhibit breast cancer apoptosis.

Central and peripheral blood pressures in relation to plasma advanced glycation end products in a Chinese population.

We investigated the association of plasma AGE (advanced glycation end product) concentration with central and peripheral blood pressures and central-to-brachial blood pressure amplification in a Chinese population. The study subjects were from a newly established residential area in the suburb of Shanghai. Using the SphygmoCor system, we recorded radial arterial waveforms and derived aortic waveforms by a generalized transfer function and central systolic and pulse pressure by calibration for brachial blood pressure measured with an oscillometric device. The central-to-brachial pressure amplification was expressed as the central-to-brachial systolic blood pressure difference and pulse pressure difference and ratio. Plasma AGE concentration was measured by the enzyme-linked immunosorbent assay method and logarithmically transformed for statistical analysis. The 1051 participants (age, 55.1±13.1 years) included 663 women. After adjustment for sex, age and other confounding factors, plasma AGE concentration was associated with central but not peripheral blood pressures and with some of the pressure amplification indexes. Indeed, each 10-fold increase in plasma AGE concentration was associated with 2.94 mm Hg (P=0.04) higher central systolic blood pressure and 2.39% lower central-to-brachial pulse pressure ratio (P=0.03). In further subgroup analyses, the association was more prominent in the presence of hypercholesterolemia (+8.11 mm Hg, P=0.008) for central systolic blood pressure and in the presence of overweight and obesity (-4.89%, P=0.009), diabetes and prediabetes (-6.26%, P=0.10) or current smoking (-6.68%, P=0.045) for central-to-brachial pulse pressure ratio. In conclusion, plasma AGE concentration is independently associated with central systolic blood pressure and pulse pressure amplification, especially in the presence of several modifiable cardiovascular risk factors.

INFLUENCE OF miR-373 ON THE INVASION AND MIGRATION OF BREAST CANCER AND THE EXPRESSION LEVEL OF TARGET GENES TXNIP.

An increasing number of people die from breast cancer every year. Consequently, more research has been concentrated on the study of this type of tumour, and miR-373 resulted as an important gene for treating breast cancer. To explore the influence of miR-373 on the invasion and migration of breast cancer and the expression level of target gene TXNIP, a set of therapeutic methods were designed based on miR-373. The transfection was performed using miR-373 inhibitor; the concentration of miR-373 was controlled by inhibitor, and it was transfected into MCF-7 cell by lipofectin. Fluorescent quantitative polymerase chain reaction was used to detect the expression level of miR-373 in cells after transfection as well as that of Caspase-3 and Caspase-8. MTT assay was used to detect the influence of miR-373 inhibitor on MCF-7 cells. The expression quantity of miR-373 in cell and tissue of breast cancer with high-low invasion and migration ability was detected by qRT-PCR (quantitative real-time polymerase chain reaction), thus the influence of the expression quantity of miR-373 on the invasion and migration of cell was determined. The expression of miR-373, EMT and TXNIP was determined by Western blot. Through the identification of proteomics and bioinformatics, it was finally found that TXNIP was regulated by miR-373. The protein expression level of TXNIP was negatively correlated with the level of miR-373. Thus it was concluded that miR-373 could promote the invasion and migration of breast cancer. In addition, in the tissue and cell of breast cancer with different invasion and migration abilities, the expression level of TXNIP was negatively correlated with the level of miR-373.

Group IIa secretory phospholipase A2 (sPLA2IIa) and progression in patients with lung cancer.

OBJECTIVE: Group IIa secretory phospholipase A2 (sPLA2 IIa) plays a role in the malignant potential of several epithelial cancers. It is overexpressed in many cancer specimens and its elevated levels are correlated with high tumor grade and metastasis. Here, we evaluate the clinical significance of sPLA2 IIa in lung adenocarcinoma and the role of sPLA2 IIa in the process of cancer cell invasion and metastasis. PATIENTS AND METHODS: Immunohistochemistry was used to investigate sPLA2 IIa in surgically resected lung adenocarcinoma of 180 patients and its correlation with survival. We overexpressed sPLA2 IIa in a lung adenocarcinoma cell line with very low sPLA2 IIa levels and investigated the in vitro and in vivo effects of sPLA2 IIa expression. RESULTS: High expression of sPLA2 IIa in lung cancer tissue was significantly associated with clinical stage, metastasis, postoperative relapse and shorter patient survival. The overexpression of sPLA2 IIa enhanced xenograft tumor growth and invasion in vitro. CONCLUSIONS: sPLA2 IIa expression can predict the clinical outcome of lung adenocarcinoma patients. sPLA2 IIa is a novel invasion-promoting gene in lung adenocarcinoma.

Screening of differentially expressed genes related to ischemic stroke and functional analysis with DNA microarray.

BACKGROUND: Prognostic blood biomarkers in the setting of acute ischemic stroke have become increasingly relevant for risk stratification, monitoring disease and response to therapies, developing targets for neuroprotective treatment and as surrogate end points for treatment trials. AIM: We aim to find the feature genes which can accurately detect acute ischemic stroke and perform function analysis of these crucial genes in peripheral blood mononuclear cells. MATERIALS AND METHODS: The gene expression profile GSE22255 was downloaded from Gene Expression Omnibus (GEO) database which includes 20 ischemic stroke patients and 20 controls. The differentially expressed genes between patients and controls samples were identified with packages in R language. The selected differentially expressed genes were further analyzed using bioinformatics methods. Software STRING (Search Tool for the Retrieval of Interacting Genes) was used to establish co-expression network. GOTM (General Ocean Turbulence Model) software was used to obtain differentially expressed gene enriched modules. The functions of genes in modules were analyzed by using software GeneCodis. RESULTS: A total of 37 genes were identified as differentially expressed genes by comparing peripheral blood mononuclear cells gene expression of ischemic stroke patients and 20 controls. A co-expression network was constructed within 30 differentially expressed genes, among which gene interleukin-8 (IL-8) and tumor necrosis factor (TNF) showed the highest node degree. Genes in the module containing IL-8 and TNF were significantly enriched in 6 biological functions, and the most significant function was respond to stimulation. CONCLUSIONS: Our results highlight that genes IL-8 and TNF have close relationship with acute ischemic stroke, and the expression patterns of these genes may be valid targets for new medications able to modify the ischemic stroke process.

Clinical significance of serum matrix metalloproteinase-13 levels in patients with esophageal squamous cell carcinoma (ESCC).

OBJECTIVES: Matrix metalloproteinase-13 (MMP13) is a highly regulated zinc-dependent endopeptidase and has been reported to be associated with vascular invasion and lymph node metastasis and predicts poor outcome for relatively early stage in esophageal squamous cell carcinoma (ESCC) patients. However, the role of the serum MMP-13 levels in ESCC is still unknown. In the present study, we investigate the clinical significance of MMP-13 levels in patients with ESCC. PATIENTS AND METHODS: The serum level of MMP-13 was measured with commercially available ELISA kit in 112 healthy controls and 141 ESCC patients prior to surgical resection. Statistical associations between clinicopathological observations and MMP-13 levels were determined using the Mann-Whitney U test. The clinical value of MMP-13 level as a prognostic parameter was evaluated using the Cox's proportional hazards model. RESULTS: The results showed compared with the healthy control group (74.5±12.3 ng/ml), ESCC patients tended to have significantly higher serum MMP-13 concentrations (86.2 ± 14.6 ng/ml) (p < 0.05). Elevation of MMP-13 levels (≥ 76.4 ng/ml) was observed in 61.7% (87/141) of patients with ESCC, and 18.4% (26/141) in healthy controls. MMP-13 levels were associated with lymph node metastasis (p < 0.001), distant metastasis (p < 0.001), histological differentiation (p = 0.026), T classification (p < 0.005), but not with the tumor size, clinical stage, age and gender of the patients or tumor location. Multivariate analysis revealed that patients with an elevated level of MMP-13 (≥ 76.4 ng/ml) had significantly lower 5 year survival rate than those with non-elevated MMP-13 (< 76.4 ng/ml, log-rank p < 0.001). CONCLUSIONS: It is suggested that the elevated level of preoperative MMP-13 was found to associate with tumor progression and poor survival in patients with ESCC.

Defining MAP3 kinases required for MDA-MB-231 cell tumor growth and metastasis.

Analysis of patient tumors suggests that multiple MAP3 kinases (MAP3Ks) are critical for growth and metastasis of cancer cells. MAP3Ks selectively control the activation of extracellular signal-regulated kinase 1/2 (ERK1/2), Jun N-terminal kinase (JNK), p38 and ERK5 in response to receptor tyrosine kinases and GTPases. We used MDA-MB-231 cells because of their ability to metastasize from the breast fat pad to distant lymph nodes for an orthotopic xenograft model to screen the function of seven MAP3Ks in controlling tumor growth and metastasis. Stable short hairpin RNA (shRNA) knockdown was used to inhibit the expression of each of the seven MAP3Ks, which were selected for their differential regulation of the MAPK network. The screen identified two MAP3Ks, MEKK2 and MLK3, whose shRNA knockdown caused significant inhibition of both tumor growth and metastasis. Neither MEKK2 nor MLK3 have been previously shown to regulate tumor growth and metastasis in vivo. These results demonstrated that MAP3Ks, which differentially activate JNK, p38 and ERK5, are necessary for xenograft tumor growth and metastasis of MDA-MB-231 tumors. The requirement for MAP3Ks signaling through multiple MAPK pathways explains why several members of the MAPK network are activated in cancer. MEKK2 was required for epidermal growth factor receptor and Her2/Neu activation of ERK5, with ERK5 being required for metastasis. Loss of MLK3 expression increased mitotic infidelity and apoptosis in vitro. Knockdown of MEKK2 and MLK3 resulted in increased apoptosis in orthotopic xenografts relative to control tumors in mice, inhibiting both tumor growth and metastasis; MEKK2 and MLK3 represent untargeted kinases in tumor biology for potential therapeutic development.

Elevated tissue factor expression contributes to exacerbated diabetic nephropathy in mice lacking eNOS fed a high fat diet.

BACKGROUND: Human eNOS (NOS3) polymorphisms that lower its expression are associated with advanced diabetic nephropathy (DN), and the lack of eNOS accelerates DN in diabetic mice. Diabetes is associated with fibrin deposition. Lack of nitric oxide and fatty acids stimulates the NF-kB pathway, which increases tissue factor (TF). OBJECTIVES: To test the hypothesis that TF contributes to the severity of DN in the diabetic eNOS(-/-) mice fed a high-fat diet (HF). METHODS: We made eNOS(-/-) and wild-type mice diabetic with streptozotocin. Half of them were placed on HF. RESULTS: Blood glucose levels were not affected by either the diet or eNOS genotype. Lack of eNOS in the diabetic mice increased urinary albumin excretion, glomerulosclerosis, interstitial fibrosis, and glomerular basement membrane thickness. HF by itself did not affect DN in the wild-type mice, but significantly enhanced DN in eNOS(-/-) mice. More than half of diabetic eNOS(-/-) mice on HF died prematurely with signs of thrombotic complications. Diabetic kidneys contained fibrin and TF, and their levels were increased by the lack of eNOS and by HF in an additive fashion. The HF diet increased the kidney expression of inflammatory genes. The increase in TF preceded DN, and administration of an anti-mouse TF antibody to diabetic mice reduced the expression of inflammatory genes. CONCLUSION: Together, these data indicate a causal link between TF and the exacerbation of DN in eNOS(-/-) mice. The condition is significantly worsened by enhanced inflammatory responses to an HF diet via TF.

The changes of aquaporin 2 in the graft of acute rejection rat renal transplantation model.

AIM: To investigate the significance and changes of Aquaporin 2 (AQP2) in the rat renal graft of acute rejection (AR). METHODS: Wistar recipients of Spraque-Dawley or Wistar renal grafts were treated with cyclosporine (CsA). Renal grafts were harvested at various times after transplantation for analysis of the levels of AQP2 mRNA and protein of by RT-PCR and immunohistochemistry. RESULTS: The expression of AQP2 mRNA and protein in the acutely rejecting were grafts significantly decreased (P < 0.05) compared with the control group. But the expression of AQP2 mRNA and protein in the syngeneic grafts (sTX) versus the immunosuppression group (aTX+CsA) showed no difference compared with a control group (P > 0.05). Furthermore, at day 5 and day 7 after transplantation the expressions of AQP2 expression in the allogeneic group (aTX) were decreased significantly compared with day 3 after transplantation (P < 0.05). In addition, there was no remarkable difference at day 5 or 7 after transplantation. CONCLUSION: AQP2 mRNA and protein expressions were down-regulated during renal transplant acute rejection, which had no relationship to the ischemia reperfusion injury and denervation damage. Furthermore, CsA administration after kidney transplantation blunted this down-regulation (P > 0.05).

Levels of microparticle tissue factor activity correlate with coagulation activation in endotoxemic mice.

BACKGROUND: Tissue factor (TF) is present in blood in various forms, including small membrane vesicles called microparticles (MPs). Elevated levels of these MPs appear to play a role in the pathogenesis of thrombosis in a variety of diseases, including sepsis. OBJECTIVE: Measure levels of MP TF activity and activation of coagulation in control and endotoxemic mice. MATERIALS AND METHODS: MPs were prepared from plasma by centrifugation. The procoagulant activity (PCA) of MPs was measured using a two-stage chromogenic assay. We also measured levels of thrombin-antithrombin and the number of MPs. RESULTS: Lipopolysaccharide (LPS) increased MP PCA in wild-type mice; this PCA was significantly reduced by an anti-mouse TF antibody (1H1) but not with an anti-human TF antibody (HTF-1). Conversely, in mice expressing only human TF, MP PCA was inhibited by HTF-1 but not 1H1. MPs from wild-type mice had 6-fold higher levels of PCA using mouse factor (F)VIIa compared with human FVIIa, which is consistent with reported species-specific differences in FVIIa. Mice expressing low levels of human TF had significantly lower levels of MP TF activity and TAT than mice expressing high levels of human TF; however, there were similar levels of phosphatidylserine (PS)-positive MPs. Importantly, levels of MP TF activity in wild-type mice correlated with levels of TAT but not with PS-positive MPs in endotoxemic mice. CONCLUSION: These results suggest that the levels of TF-positive MPs can be used as a biomarker for evaluating the risk of disseminated intravascular coagulation in endotoxemia.