Intracellular manipulation and measurement with multipole magnetic tweezers

The capability to directly interrogate intracellular structures inside a single cell for measurement and manipulation is important for understanding subcellular and suborganelle activities, diagnosing diseases, and developing new therapeutic approaches. Compared with measurements of single cells, physical measurement and manipulation of subcellular structures and organelles remain underexplored. To improve intracellular physical measurement and manipulation, we have developed a multipole magnetic tweezers system for micromanipulation involving submicrometer position control and piconewton force control of a submicrometer magnetic bead inside a single cell for measurement in different locations (spatial) and different time points (temporal). The bead was three-dimensionally positioned in the cell using a generalized predictive controller that addresses the control challenge caused by the low bandwidth of visual feedback from high-resolution confocal imaging. The average positioning error was quantified to be 0.4 μm, slightly larger than the Brownian motion–imposed constraint (0.31 μm). The system is also capable of applying a force up to 60 pN with a resolution of 4 pN for a period of time longer than 30 min. The measurement results revealed that significantly higher stiffness exists in the nucleus’ major axis than in the minor axis. This stiffness polarity is likely attributed to the aligned actin filament. We also showed that the nucleus stiffens upon the application of an intracellularly applied force, which can be attributed to the response of structural protein lamin A/C and the intracellular stress fiber actin filaments.

Erythropoietin Ameliorates Lung Injury by Accelerating Pulmonary Endothelium Cell Proliferation via Janus Kinase-Signal Transducer and Activator of Transcription 3 Pathway After Kidney Ischemia and Reperfusion Injury

BACKGROUND/AIMS

Kidney ischemia and reperfusion injury could cause microvascular barrier dysfunction, lung inflammatory cascades activation, and programmed cell death of pulmonary endothelium, leading to acute lung injury. Our study aimed at determining whether erythropoietin (EPO) can ameliorate lung dysfunction following renal ischemia and reperfusion (IR) injury and explored the underlying mechanisms.

METHODS

In vivo, C57BL/6 mice received EPO (6000 U/kg) before right renal vascular pedicles clamping for 30 minutes, followed by 24 hours of reperfusion. The lung histopathologic changes and inflammatory cytokines expression were assessed. In vitro, cultured human umbilical vein endothelial cells were treated with EPO, and apoptosis rate, proliferation capacity, and phosphorylation status of the Janus kinase-signal transducer and activator of transcription 3 (Jak-STAT3) pathway were measured respectively in the presence or absence of lipopolysaccharide stimulation.

RESULTS

In vivo, EPO remarkably attenuated pulmonary interstitial and alveolar epithelial edema caused by renal IR injury. In vitro, the proliferation capacity of human umbilical vein endothelial cells was significantly increased under EPO stimulation, which correlated with changes in Jak-STAT3 signaling.

CONCLUSION

Our data indicated that EPO is able to ameliorate acute lung tissue damage induced by renal IR, and at least in part, via the Jak-STAT3 pathway.

[Study on genetic structure differences and adjustment strategies in different areas of China]

Objective: To describe the genetic structure of populations in different areas of China, and explore the effects of different strategies to control the confounding factors of the genetic structure in cohort studies. Methods: By using the genome-wide association study (GWAS) on data of 4 500 samples from 10 areas of the China Kadoorie Biobank (CKB), we performed principal components analysis to extract the first and second principal components of the samples for the component two-dimensional diagram generation, and then compared them with the source of sample area to analyze the characteristics of genetic structure of the samples from different areas of China. Based on the CKB cohort data, a simulation data set with cluster sample characteristics such as genetic structure differences and extensive kinship was generated; and the effects of different analysis strategies including traditional analysis scheme and mixed linear model on the inflation factor (λ) were evaluated. Results: There were significant genetic structure differences in different areas of China. Distribution of the principal components of the population genetic structure was basically consistent with the geographical distribution of the project area. The first principal component corresponds to the latitude of different areas, and the second principal component corresponds to the longitude of different areas. The generated simulation data showed high false positive rate (λ=1.16), even if the principal components of the genetic structure was adjusted or the area specific subgroup analysis was performed, λ could not be effectively controlled (λ>1.05); while, by using a mixed linear model adjusting for the kinship matrix, λ was effectively controlled regardless of whether the genetic structure principal component was further adjusted (λ=0.99). Conclusions: There were large differences in genetic structure among populations in different areas of China. In molecular epidemiology studies, bias caused by population genetic structure needs to be carefully treated. For large cohort data with complex genetic structure and extensive kinship, it is necessary to use a mixed linear model for association analysis.

Semi-dominant mutation in the cysteine-rich receptor-like kinase gene, ALS1, conducts constitutive defence response in rice

Plants have evolved a sophisticated two-branch defence system to prevent the growth and spread of pathogen infection. The novel Cys-rich repeat (CRR) containing receptor-like kinases, known as CRKs, were reported to mediate defence resistance in plants. For rice, there are only two reports of CRKs. A semi-dominant lesion mimic mutant als1 (apoptosis leaf and sheath 1) in rice was identified to demonstrate spontaneous lesions on the leaf blade and sheath. A map-based cloning strategy was used for fine mapping and cloning of ALS1, which was confirmed to be a typical CRK in rice. Functional studies of ALS1 were conducted, including phylogenetic analysis, expression analysis, subcellular location and blast resistance identification. Most pathogenesis-related (PR) genes and other defence-related genes were activated and up-regulated to a high degree. ALS1 was expressed mainly in the leaf blade and sheath, in which further study revealed that ALS1 was present in the vascular bundles. ALS1 was located in the cell membrane of rice protoplasts, and its mutation did not change its subcellular location. Jasmonic acid (JA) and salicylic acid (SA) accumulation were observed in als1, and enhanced blast resistance was also observed. The mutation of ALS1 caused a constitutively activated defence response in als1. The results of our study imply that ALS1 participates in a defence response resembling the common SA-, JA- and NH1-mediated defence responses in rice.

Prevalence and Potential Associated Factors of Depression among Chinese Older Inpatients

INTRODUCTION

Little is known about the current representative depression situation among Chinese older inpatients. The aim of this study is to examine prevalence of depression and associated risk factors among Chinese older inpatients by a large-scale cross-sectional national survey.

METHODS

This study is based on baseline survey data from a large-scale cohort study in a representative sample of Chinese older inpatients. The procedure of this study involves physical examination and face-to-face questionnaire interviews. Depression was assessed based on the Geriatric Depression Scale 15. Mixed-effect Poisson regression model was used to examine the relationship between depression and covariates by controlling the cluster effect of hospital wards.

RESULTS

Of all 9727 respondents, the mean age of all respondents was 72.4±5.7 years, from 65 to 97. The average GDS score was 2 (1, 4). The prevalence rate of depression was 16.7% (95%CI: 15.8-17.4%) among older inpatients. The prevalence rates were 14.6% for males and 19.5% for females respectively. After controlling the cluster effect of hospital wards, age, gender, ADL score, educational level, BMI, frail, marriage, falls, alcohol drinking, cognitive function, living conditions, vision, hearing, sleep and defecation function were associated with depression. Emaciation (OR=1.176, 95%CI: 1.107-1.249), frail (OR=1.562, 95%CI: 1.489-1.639), divorced or widowed (OR=1.083 95%CI: 1.017-1.153), living in the bungalow (OR=1.075, 95%CI: 1.023-1.130), falls (OR=1.078, 95%CI: 1.030-1.128), cognitive function (OR=1.142, 95%CI: 1.091-1.195), vision dysfunction (OR=1.125, 95%CI: 1.076-1.177), hearing dysfunction (OR=1.061, 95%CI: 1.011-1.113), sleep dysfunction (OR=1.237, 95%CI: 1.194-1.282), defecation dysfunction (OR=1.160, 95%CI: 1.103-1.221) could increase prevalence risk of depression.

CONCLUSIONS

There was a high prevalence of depression among Chinese older inpatients. Demographic characteristics, physical and mental conditions indicators have strong effect on prevalence and strength of depression. Therefore, it is essential to assess depression and perform comprehensive measures to improve physical and mental conditions in order to manage depressive symptoms in older inpatients.

Altered N-methyl D-aspartate receptor subunit expression causes changes to the circadian clock and cell phenotype in osteoarthritic chondrocytes

The chondrocyte circadian clock is altered in osteoarthritis. This change is implicated in the disease-associated changes in chondrocyte phenotype and cartilage loss. Why the clock is changed is unknown. N-methyl-D-aspartate receptors (NMDAR) are critical for regulating the hypothalamic clock. Chondrocytes also express NMDAR and the type of NMDAR subunits expressed changes in osteoarthritis.

OBJECTIVE

To determine if NMDAR regulate the chondrocyte clock and phenotype.

DESIGN

Chondrocytes isolated from macroscopically-normal (MN) and osteoarthritic human cartilage were treated with NMDAR antagonists or transfected with GRIN2A or GRIN2B-targetting siRNA. H5 chondrocytes were transfected with GluN2B-expression plasmids. Clock genes and chondrocyte phenotypic markers were measured by RT-qPCR.

RESULTS

PER2 amplitude was higher and BMAL1 amplitude lower in osteoarthritic compared to MN chondrocytes. In osteoarthritic chondrocytes, NMDAR inhibition restored PER2 and BMAL1 expression to levels similar to MN chondrocytes, and resulted in reduced MMP13 and COL10A1. Paradoxically, NMDAR inhibition in MN chondrocytes resulted in increased PER2, decreased BMAL1 and increased MMP13 and COL10A1. Osteoarthritic, but not MN chondrocytes expressed GluN2B NMDAR subunits. GluN2B knockdown in osteoarthritic chondrocytes restored expression of circadian clock components and phenotypic markers to levels similar to MN chondrocytes. Ectopic expression of GluN2B resulted in reduced BMAL1, increased PER2 and altered SOX9, RUNX2 and MMP13 expression. Knockdown of PER2 mitigated the effects of GluN2B on SOX9 and MMP13.

CONCLUSIONS

NMDAR regulate the chondrocyte clock and phenotype suggesting NMDAR may also regulate clocks in other peripheral tissues. GluN2B expression in osteoarthritis may contribute to pathology by altering the chondrocyte clock.

Natural history of serum HBV-RNA in chronic HBV infection

Virus-like particles encapsulating HBV-RNA represent a serum biomarker for assessing viral replication activity in clinical practice. However, baseline levels of serum HBV-RNA and their associations with viral replicative intermediates and liver disease in phases of chronic hepatitis B remain unknown. In this cross-sectional study, 102 patients were categorized into immune-tolerant (IT), HBeAg-positive immune active (HBeAg+IA), inactive carrier (IC) and HBeAg-negative immune active (HBeAg-IA) phases. HBV-RNA in serum samples and in 66 paired liver biopsies were quantified and correlated with serum ALT levels, histopathological scores and the levels of other viral replicative intermediates. Mean levels of serum HBV-RNA differed among phases, with the highest levels among IT (6.78 ± 0.83 log₁₀ copies mL^-1 ) patients, followed by HBeAg+IA (5.73 ± 1.16 log₁₀ copies mL^-1 ), HBeAg-IA (4.52 ± 1.25 log₁₀ copies mL^-1 ) and IC (2.96 ± 0.40 log₁₀ copies mL^-1 ) patients. Serum HBV-RNA levels correlated with HBV DNA in all phases, although correlations with other viral replicative intermediates weakened or disappeared when cases were stratified into phases. Distinct compositions of viral products were found among phases: the ratio of HBsAg to serum HBV-RNA was highest in IC patients, while the ratio of serum HBV-RNA to intrahepatic HBV-RNA and the ratio of intrahepatic HBV-DNA to intrahepatic HBV-RNA were significantly higher in IT patients. In conclusion, baseline levels of HBV-RNA and the composition of viral replicative intermediates differ significantly across the natural course of chronic HBV infection. These findings shed light on the nature of viral replication and pathogenesis of disease among different phases of chronic HBV infection.

An effective diagnostic index for lymphoma-associated hemophagocytic syndrome

BACKGROUND

Lymphoma-associated hemophagocytic syndrome (LAHS) is a highly fatal immune disorder. Poor prognosis is partly attributed to under diagnosis or delayed diagnosis.

AIM

Early identification of LAHS patients based on the laboratory findings could improve the outcomes.

DESIGN

Retrospective observational cross-sectional study.

METHODS

From January 2011 to June 2016, 282 adult patients with hemophagocytosis in bone marrow were enrolled, and 114 hemophagocytic lymphohistiocytosis (HLH) patients with definite underlying cause were finally included for analysis. The HLH patients were further divided into LAHS (76 out of 114) and non-malignancy-associated HLH (38 out of 114) groups.

RESULTS

Compared to non-malignancy-associated HLH, LAHS patients had significantly elevated lactate dehydrogenase (LDH) levels, increased thickness of spleen, higher proportion of patients with lymphadenopathy and significantly decreased peripheral blood cell count. In multivariate logistic regression model analysis, thickness of spleen ≥5 cm (OR = 17.9, 95%CI 1.35-236.6; P = 0.028), IL-6 level ≥55.1 pg/ml (OR = 12.01, 95%CI 1.03-138.9; P = 0.047) and IL-10 level ≥425.9 pg/ml (OR = 51.18, 95%CI 2.53-1035.1; P = 0.010) were independent predictors of LAHS diagnosis. Based on the regression parameters, we established a diagnostic index with weighted risk scores of 1 assigned to thickness of spleen and IL-6 level respectively, and a score of 3 assigned to IL-10 level. A diagnostic index ≥ 2 points had the best AUC value (0.889) with 84.2% of sensitivity and 93.7% of specificity for predicting LAHS.

CONCLUSIONS

LAHS can be considered when HLH patients have a diagnostic index ≥2 points, so actively looking for evidence of lymphoma and effective chemotherapy may be necessary.

Isoflurane enhances the malignant potential of glioblastoma stem cells by promoting their viability, mobility in vitro and migratory capacity in vivo

BACKGROUND

Isoflurane is one of the most common general anaesthetics used during surgical procedures, including tumour resection. However, the effects of isoflurane on the viability and migration capacity of cancer cells, specifically in the context of brain cancer cells, remain unclear. Therefore, the aim of this study was to evaluate the influence that isoflurane has on the function of glioblastoma stem cells (GCSs) in regards to cell proliferation, survival and migration.

METHOD

U251-GSCs were exposed to isoflurane at clinically relevant concentrations and incubation times. The effects on proliferation, survival and migration capacities of the cells were evaluated in vitro. The potential risk was assessed in mice by intracranial injection of U251-GSCs pretreated with isoflurane. Furthermore, the average tumour volume and migration distance of U251-GSCs from the tumour centre were calculated.

RESULTS

Exposure of U251-GSCs to 1.2% isoflurane for 6 h resulted in increased proliferation (P<0.05) and decreased apoptosis rate (P<0.05) when compared with the control group. In addition, isoflurane exposure caused increased migration capacity in vitro (P<0.05) and the distance migrated was increased in vivo (P<0.05).

CONCLUSION

Clinically relevant concentrations and incubation times of isoflurane could promote the viability and mobility of U251-GSCs, suggesting this general anaesthetic may have detrimental effects in glioblastoma by facilitating its growth and migration.

Clofazimine improves clinical outcomes in multidrug-resistant tuberculosis: a randomized controlled trial

OBJECTIVES

We carried out a randomized multicentre study in China to investigate whether the clofazimine would improve the efficacy of the standardized regimen in patients with multidrug-resistant tuberculosis (MDR-TB).

METHODS

Patients with MDR-TB managed in 17 TB specialist hospitals in China between September 2009 and September 2011 were randomly assigned to the treatment groups at enrolment. In the intervention group, 100 mg clofazimine per day was added to the standardized regimen. The primary outcome was the proportion of patients with successful outcomes.

RESULTS

From the 156 patients that were screened, 74 were assigned to the control group and 66 to the clofazimine group. Of the 66 cases analysed for clinical outcome in the clofazimine group, 36 patients were cured, and seven completed treatment, yielding a favourable outcome rate of 65.1%. The proportion of patients with favourable outcomes receiving the control regimen was 47.3% (35/74), which was significantly lower than that in the clofazimine group (p 0.034, relative risk 0.661, 95% CI 0.243-0.949).

CONCLUSIONS

The addition of clofazimine to the standard regimen improved the treatment of MDR-TB.

[Clinical features of acute diffuse pulmonary exudative disorders]

Objective: To analyze the clinical features of acute diffuse pulmonary exudative disorders. Methods: The data were collected from patients who were hospitalized in respiratory intensive care unit (RICU) of Beijing Chaoyang Hospital affiliated to the Capital Medical University during January 2009 to December 2011, and had acute clinical course with imaging findings of diffuse pulmonary infiltrated shadows (similar to acute respiratory distress syndrome (ARDS)). The causes of disease and clinical features were analyzed. Results: A total of 86 patients with acute diffuse pulmonary exudative disorders were included. Sixty-two (72.1%) were males, with a mean age of (58.6±16.4) years old; 24(27.9%) were females, with a mean age of (48.2±18.3) years old. The duration of the disease before administration was (11.5±5.2) days, and RICU stay was (15.5±9.5) days, with hospital mortality of 40.7% and the average hospitalization cost of 101 thousand RMB. The main cause was infection, which occurred in 53 cases (61.6%) (virus in 21 cases, bacteria in 14 cases, fungus in 11 cases, pneumocystis in 15 cases and others in 3 cases, mixed infection in 11 cases). Interstitial pneumonia occurred in 12 cases (idiopathic interstitial pneumonia in 9 cases: cryptogenic organizing pneumonia in 3 cases, the acute exacerbation of idiopathic pulmonary fibrosis in 3 cases, nonspecific interstitial pneumonia in 1 case, acute interstitial pneumonia in 2 cases, and connective tissue disease in 3 cases), aspiration pneumonia in 10 cases, acute left heart failure in 6 cases, and exogenous pulmonary ARDS in 5 cases. Conclusions: The main cause of acute diffuse pulmonary exudative disorders is pulmonary infection, followed by interstitial pneumonia. The hospital mortality and hospitalization cost are high.

[Facial symmetry after conservative treatment of unilateral condylar fracture in children: a three-dimensional study]

Objective: To investigate the influence of condylar fractures on the growth of condylars after conservative treatments by three-dimensional measurement. Methods: Twenty three children with unilateral condylar fracture followed-up for at least 1 year in Shanghai Ninth People's Hospital were included from June 2016 to March 2017. CT scans were performed for each patient. Three-dimensional virtual skulls were reconstructed and measuring points were defined with Simplant 11.04 software. The depth of glenoid fossa, height of articular eminence, width, height and depth of condylar, deviation of pogonion were measured. Statistical analyses were conducted to assess difference between the bifid group and the normal group. Results: No difference was observed in the vertical position of crest of the articular eminence between two groups (P=0.110). The vertical position of roof of the glenoid fossa in bifid side was significantly superior than the one in normal side (P=0.010). Bifid side had a shorter (P=0.002) and wider(P=0.002) condylar than normal side did. No difference was observed in the depth of condylar between two groups (P=0.071). The average deviation of pogonion was (0.69±1.75) mm (P=0.072) from sagittal plan. Conclusions: This short-termed study indicates that children's growth potential of condylar is under average after conservative treatments. Because the bone hyperosteogeny of glenoid fossa compensates the hypotrophy of condylar, no deviation of pogonion is detected.

Genomic signatures reveal selection of characteristics within and between Meishan pig populations

The Chinese Meishan pig breed is well known for its high prolificacy. Moreover, this breed can be divided into three types based on their body size: big Meishan, middle Meishan (MMS) and small Meishan (SMS) pigs. Few studies have reported on the genetic signatures of Meishan pigs, particularly on a genome-wide scale. Exploring for genetic signatures could be quite valuable for revealing the genetic architecture of phenotypic variation. Thus, we performed research in two parts based on the genome reducing and sequencing data of 143 Meishan pigs (74 MMS pigs, 69 SMS pigs). First, we detected the selection signatures among all Meishan pigs studied using the relative extended haplotype homozygosity test. Second, we detected the selection signatures between MMS and SMS pigs using the cross-population extended haplotype homozygosity and F_ST methods. A total of 111 398 SNPs were identified from the sequenced genomes. In the population analysis, the most significant genes were associated with the mental development (RGMA), reproduction (HDAC4, FOXL2) and lipid metabolism (ACACB). From the cross-population analysis, we detected genes related to body weight (SPDEF, PACSIN1) in both methods. We suggest that rs341373351, located within the PACSIN1 gene, might be the causal variant. This study may have achieved consistency between selection signatures and characteristics within and between Meishan pig populations. These findings can provide insight into investigating the molecular background of high prolificacy and body size in pig.

Temperature- and field-driven spin reorientations in triple-layer ruthenate Sr4Ru3O10

Sr₄Ru₃O₁₀, the n = 3 member of the Ruddlesden-Popper type ruthenate Sr_n+1Ru_nO_3n+1, is known to exhibit a peculiar metamagnetic transition in an in-plane magnetic field. However, the nature of both the temperature- and field-dependent phase transitions remains as a topic of debate. Here, we have investigated the magnetic transitions of Sr₄Ru₃O₁₀ via single-crystal neutron diffraction measurements. At zero field, we find that the system undergoes a ferromagnetic transition with both in-plane and out-of-plane magnetic components at T_c ≈ 100 K. Below T ^* = 50 K, the magnetic moments incline continuously toward the out-of-plane direction. At T = 1.5 K, where the spins are nearly aligned along the c axis, a spin reorientation occurs above a critical field B_c, giving rise to a spin component perpendicular to the plane defined by the field direction and the c axis. We suggest that both the temperature- and field-driven spin reorientations are associated with a change in the magnetocrystalline anisotropy, which is strongly coupled to the lattice degrees of freedom. This study elucidates the long-standing puzzles on the zero-field magnetic orders of Sr₄Ru₃O₁₀ and provides new insights into the nature of the field-induced metamagnetic transition.