DNA damage primes hematopoietic stem cells for direct megakaryopoiesis.

Hematopoietic stem cells (HSCs) reside in the bone marrow (BM), can self-renew, and generate all cells of the hematopoietic system. 1 Most hematopoietic lineages arise through successive, increasingly lineage-committed progenitors. In contrast, megakaryocytes (MKs), hyperploid cells that generate platelets essential to hemostasis, can derive rapidly and directly from HSCs. 2 The underlying mechanism is unknown however. Here we show that DNA damage and subsequent arrest in the G2 phase of the cell cycle rapidly induce MK commitment specifically in HSCs, but not in progenitors, through an initially predominantly post-transcriptional mechanism. Cycling HSCs show extensive replication-induced DNA damage associated with uracil misincorporation in vivo and in vitro . Consistent with this notion, thymidine attenuated DNA damage, rescued HSC maintenance and reduced the generation of CD41 + MK-committed HSCs in vitro . Similarly, overexpression of the dUTP-scavenging enzyme, dUTPase, enhanced in vitro maintenance of HSCs. We conclude that a DNA damage response drives direct megakaryopoiesis and that replication stress-induced direct megakaryopoiesis, at least in part caused by uracil misincorporation, is a barrier to HSC maintenance in vitro . DNA damage-induced direct megakaryopoiesis may allow rapid generation of a lineage essential to immediate organismal survival, while simultaneously removing damaged HSCs and potentially avoiding malignant transformation of self-renewing stem cells.

Effects of sleep quality on suicide risk in COVID-19 patients: The chain mediating of anxiety and depressive symptoms.

Background: Although current studies have identified sleep disorders as an independent risk factor for suicide, the relationship between sleep disorders and suicide risk has not been well established. This study explored whether anxiety and depressive symptoms are used as mediators to participate in the impact of sleep quality on suicide risk. Methods: This is a cross-sectional study. We administered a psychological questionnaire to the participants, using a combination of self-assessment and psychiatrist assessment.Sleep quality, suicide risk, level of anxiety and depressive symptoms were assessed by PSQI, NGASR, SAS and SDS.The study subjects were 391 hospitalized COVID-19 patients from Wuhan hospitals. We used model 6 in the PROCESS (version 3.5) plug-in of SPSS software to conduct mediation test with sleep quality as the independent variable, suicide risk as the dependent variable, level of anxiety and depressive symptoms as intermediate variables. Results: The severity of anxiety and depressive symptoms and the risk of suicide in the sleep disorder group (63.15 ± 13.71, 59.85 ± 13.38, 6.52 ± 3.67) were higher than those in the non-sleep disorder group (49.83 ± 13.14, 44.87 ± 10.19, 2.87 ± 3.26) (P < 0.001). The mediation model works well, The total indirect effect was 0.22 (95%CI = [0.17, 0.28]), and the direct effect was 0.16 (95%CI = [0.08, 0.24]). Limitations: This study used a self-assessment scale. Conclusions: Anxiety and depressive symptoms played a chain mediating role between sleep quality and suicide risk.

Efficacy of air purifier therapy for patients with allergic asthma.

OBJECTIVES: This study aimed to evaluate the efficacy of air purifier therapy for patients with allergic asthma. METHODS: Thirty-eight subjects were categorized under two groups namely treatment group and control group. All subjects were under 18 years of age and they had been clinically diagnosed with allergic asthma. The treatment group used high efficiency particulate air (HEPA) purifiers for six consecutive months, and the control group did not use the air filters. Particulate matter (PM) data and dust samples (from bedding and a static point) were collected from the subjects' bedrooms before they started using the air purifiers and each month thereafter. Simultaneously, the subjects were asked to complete a questionnaire for the Asthma Control Test (ACT) or Childhood Asthma Control Test (C-ACT). Fractional exhaled nitric oxide (FENO) tests were performed at the start and end of the study. The concentrations of Der p1 and Der f1 were measured in the dust samples. RESULTS: (1) After utilizing the air purifier, the concentrations of house dust mite (HDM) allergens (Der p1+ Der f1) in the dust samples decreased. In addition, the PMindoor/outdoor values significantly decreased. (2) The ACT and C-ACT scores in the treatment group maintained a steady significant upward trend. (3) At the end of the study, the FENO levels in both groups were lower, although the differences were not significant. CONCLUSIONS: It is witnessed that HEPA air purifiers can decrease indoor HDM allergen and PM levels and improve the quality of life for allergic asthma patients.

Vitamin D status at birth and acute respiratory infection hospitalisation during infancy.

BACKGROUND: Hospital admission for acute respiratory infections (ARIs) during early childhood is a global public health concern. Vitamin D deficiency is prevalent during pregnancy and infancy. Evidence indicates that vitamin D supplementation prevents ARIs. OBJECTIVES: To determine whether vitamin D deficiency at birth is associated with ARI hospitalisations during infancy. METHODS: We performed a nested case-control study in children aged 0-12 months. Cases had ≥1 ARI hospitalisation and 4 controls were individually matched to each case. Newborn 25(OH)D concentration was measured on dried blood spots using two-dimensional liquid chromatography-tandem mass spectrometry. Hospital admissions were measured using health care records. Median serum 25(OH)D concentration in cases and controls was compared, and covariates of ARI hospitalisation during infancy were assessed using conditional logistic regression analysis. RESULTS: Six per cent of the cohort (n = 384) had an ARI hospitalisation during infancy, and 1536 controls were matched to cases. Median DBS [25(OH)D] was lower among ARI cases than controls (46 nmol/l vs. 61 nmol/L). Median 25(OH)D levels were lower for those hospitalised ≥2 times (47, IQR 36, 58) vs. those hospitalised once (52, IQR 42, 62) vs. the controls and also lower for those who stayed in the hospital for ≥3 days (45, IQR 36, 54) vs 1-2 days (48, IQR 38, 59) compared to the controls. After adjustment for season of birth and covariates describing demographic, antenatal, perinatal, and infant characteristics, DBS 25(OH)D concentration (<50 nmol/L) at birth was associated with increased odds of ARI hospitalisation during infancy (odds ratio 2.20, 95% confidence interval 1.48, 2.91). CONCLUSIONS: Vitamin D deficiency at birth is associated with increased odds of ARI hospitalisations in infants. The findings have implications for a developed country like New Zealand where vitamin D supplementation is not routinely recommended and the burden of ARI hospitalisation in young children is high.

Plasma phospholipid very-long-chain SFAs in midlife and 20-year cognitive change in the Atherosclerosis Risk in Communities (ARIC): a cohort study.

BACKGROUND: Very-long-chain SFAs (VLSFAs) have recently gained considerable attention as having beneficial effects on health and aging. OBJECTIVES: The objective of this study was to assess the associations of plasma phospholipid VLSFAs [arachidic acid (20:0), behenic acid (22:0), tricosanoic acid (23:0), and lignoceric acid (24:0)] with 20-y cognitive decline in the Atherosclerosis Risk in Communities (ARIC) participants. Furthermore, this study compared the associations of plasma phospholipid VLSFAs with 5 common groups of fatty acids [i.e., total SFAs, total MUFAs, total ω-3 (n-3) PUFAs, total marine-derived ω-3 PUFAs, total ω-6 PUFAs]. METHODS: This study used a cohort study design of 3229 ARIC participants enrolled at the Minnesota field center. Fatty acids were measured at visit 1 (1987-1989); and cognition was assessed at visits 2 (1990-1992), 4 (1996-1998), and 5 (2011-2013) using 3 tests: the Delayed Word Recall Test (DWRT), the Digit-Symbol Substitution Test (DSST), and the Word Fluency Test (WFT). RESULTS: Higher proportions of plasma phospholipid total VLSFAs and each individual VLSFA were associated with less decline in WFT, a test of verbal fluency. For example, 1 SD higher in total VLSFAs at baseline was associated with 0.057 SD (95% CI: 0.018, 0.096, P = 0.004) less cognitive decline over 20 y as measured by WFT score. None of the 5 common fatty acid groups were associated with change in WFT, but a higher proportion of plasma phospholipid total MUFAs was associated with greater decline in DWRT; higher total ω-6 PUFAs with less decline in DWRT; and higher total ω-3 and total marine-derived ω-3 PUFAs with less decline in DSST. CONCLUSIONS: This study suggests that higher proportions of plasma phospholipid VLSFAs in midlife may be associated with less 20-y cognitive decline.

Muscle ultrasonography in the diagnosis of amyotrophic lateral sclerosis.

Objectives: The aims of this study were to investigate the differences of fasciculations detected by muscle ultrasonography (MUS) among patients with amyotrophic lateral sclerosis (ALS), patients with ALS mimics and healthy controls, and to propose a simplified MUS fasciculation score for the diagnosis of ALS.Methods: We included 16 patients with ALS (ALS group), 10 patients with ALS mimics (disease-control group), and 10 healthy adults (healthy control group). Subjects underwent MUS in 11 muscles, including the tongue, and bilateral upper trapezius, biceps brachii, abductor pollicis brevis, rectus femoris, and tibialis anterior.Results: The number of muscles with fasciculations per person was more in the ALS group (6.44 ± 2.56) than in the disease-control group (1.20 ± 1.87, P = 0.001) and healthy control group (0.50 ± 1.08, P < 0.001). Fasciculations in 3 of 11 muscles could predict the ALS diagnosis with high sensitivity (88.2%) and specificity (94.7%).Conclusions: Fasciculations detected by MUS can be a simple and useful diagnostic tool for ALS.

trans-Polydatin protects the mouse heart against ischemia/reperfusion injury via inhibition of the renin-angiotensin system (RAS) and Rho kinase (ROCK) activity.

BACKGROUND: Recent studies highlighted the protective benefits of a Chinese herb extract from polygonum cuspidatum, trans-polydatin, on cardiac disease. We investigated the therapeutic effect of trans-polydatin on myocardial ischemia/reperfusion (IR) injury and the underlying mechanisms related to the renin-angiotensin system (RAS) and RhoA kinase (ROCK) pathway. METHODS AND RESULTS: Experiments were performed on neonatal rats' ventricular myocytes that were subjected to hypoxia-reoxygenation (simulated IR, SIR) and on adult mice which were subjected to left anterior descending coronary artery occlusion for 45 min followed by a one-week reperfusion. trans-Polydatin significantly increased cell viability and reduced apoptosis in SIR cardiomyocytes. It was also observed to reduce the infarct size and increase the cardiac function in IR mice. trans-Polydatin decreased the expression of angiotensin and inhibited the activities of renin and angiotensin-converting enzyme. Furthermore, trans-polydatin inhibited ROCK activity, especially the angiotensin I receptor-activated ROCK pathway. CONCLUSIONS: trans-Polydatin exerts a cardio-protection against myocardial IR injury likely through inhibiting both RAS and the downstream ROCK pathway.

Preconditioning of endoplasmic reticulum stress protects against acrylonitrile-induced cytotoxicity in primary rat astrocytes: The role of autophagy.

This study explored the protective effects of endoplasmic reticulum (ER) stress preconditioning induced by 2-deoxy-d-glucose (2-DG) or oxidized dithiothreitol (DTTox) on acrylonitrile (AN)-induced cytotocity in primary rat astrocytes. Cells were pretreated with 2-DG or DTTox for different times at various concentration. Next, astrocytes were treated with 2.5mM AN for an additional 12h. Cell viability and cytotoxicity were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction and lactate dehydrogenase (LDH) leakage, respectively. Reactive oxygen species (ROS) and mitochondrial membrane potential (ΔΨm) were determined. Expression of glucose-regulated protein 78 (GRP78), phosphorylated-eukaryotic translation initiation factor 2α (p-eIF2α), microtubule-associated protein light chain 3 (LC3), P62, and Beclin1 were used to assess autophagy. In addition, 3-methyadenine (3-MA), an autophagy-specific inhibitor, was used to assess the role of autophagy in ER stress preconditioning-induced protection against AN cytotoxicity. The results showed that AN alone significantly decreased astrocytic viability and enhanced cytotoxicity. Compared to the AN-alone group, preconditioning with 2-DG or DTTox significantly increased cell viability and reduced cytotoxicity to indistinguishable levels. Decreased ROS generation and increased ΔΨm were also inherent to ER stress preconditioning with these compounds. Furthermore, autophagy was activated by both 2-DG and DTTox. Blockage of autophagy attenuated the protection afforded by 2-DG or DTTox preconditioning in AN-treated astrocytes. These results establish that ER stress preconditioning affords cellular protection against AN, and that activation of autophagy mediates the cytoprotection. Modulation of ER stress and resultant activation of autophagy may be a novel target for to ameliorate AN toxicity.

Differential protection of pre- versus post-treatment with curcumin, Trolox, and N-acetylcysteine against acrylonitrile-induced cytotoxicity in primary rat astrocytes.

OBJECTIVE: This study was designed to examine the differential protection of pre- versus post-treatment with three different antioxidants, curcumin (CUR), Trolox, and N-acetylcysteine (NAC), on acrylonitrile (AN)-induced cytotoxicity in primary rat astrocytes. METHODS: Primary astrocyte cultures were treated with CUR, Trolox and NAC for 4h prior to, or following 24h treatment with AN (2.5mM). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH) release, lipid peroxidation, glutathione, reactive oxygen species (ROS) and mitochondrial membrane potential were measured to evaluate protection associated with the three antioxidants. Knockdown of Nrf2 expression by liposome transfection with siRNA was used to confirm the role of Nrf2 activation in the protection associated with the three antioxidants. RESULTS: Compared with AN treatment alone, pre-treatment with CUR at either concentration significantly increased cell viability and mitochondrial membrane potential, and reduced glutathione levels; lipid peroxidation and ROS production were significantly decreased as well. NAC also showed significant efficacy in attenuating AN-induced toxicity at higher concentration. However, pre-treatment with Trolox failed to ameliorate the AN-induced toxicity. When post-treatment with Trolox, this antioxidant led to significant protective effects at both concentrations, while CUR and NAC were efficacious only at the higher concentrations. Knockdown of Nrf2 only abolished the protective effects of CUR pre-treatment on AN-induced cytotoxicity, while the protective effects of NAC and Trolox pre-treatment groups showed no differences between the Nrf2-knockdown and non-knockdown treatments. CONCLUSIONS: The selected antioxidants exert differential cellular protection when administered prior or subsequent to AN-induced cytotoxic events in decreasing cellular viability, antioxidative capacity and mitochondrial function, enhanced cytotoxicity and ROS production. These results suggest that antioxidants should be carefully chosen for their efficacy in preventing or diminishing oxidative damage caused by AN. The differential effect of pre- and post-treatment may be attributed to activation of the Nrf2 signaling pathway.

Effect of oxygen-driven nebulization at different oxygen flows in acute exacerbation of chronic obstructive pulmonary disease patients.

OBJECTIVES: The aim of this study was to study the effect of oxygen-driven nebulization (ODN) at different oxygen flows on heart rate, respiratory rate, SpO2, SaO2, PaO2, PaCO2 and pH of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients. METHODS: According to random number table, 9 AECOPD patients were randomly divided into 3 groups, numbered A, B and C and treated with ODN. Oxygen flow of groups A, B and C was 4-5, 6-7 and 8-9 L/min, respectively. Heart rate, respiratory rate, SpO2, SaO2, PaO2, PaCO2 and pH were recorded before ODN and 30 minutes after ODN. Statistical differences of data before or after ODN were analyzed by analysis of variance and F-test, whereas data before and after ODN were tested by paired t test. RESULTS: There was no significant difference of heart rate, respiratory rate, SpO2, PaO2, PaCO2, SaO2 and pH among 3 groups before ODN or after ODN. The heart rate was increased in all groups after ODN. But significant increase was only present in groups A and C but not in group B. SaO2 was significantly increased in group C after ODN but no statistical difference was observed between before and after ODN in groups A and B. There was no significant change in respiratory rate, SpO2, PaO2, PaCO2, SaO2 and pH between before and after ODN in all groups. CONCLUSIONS: Optimal oxygen flow in ODN-treating AECOPD patients may be 6-7 L/min.

Influence of dexamethasone on the expression levels of P-selectin protein in multiple organs of rats with severe acute pancreatitis.

OBJECTIVE: To investigate the effect of dexamethasone on the expression levels of P-selectin protein in multiple organs of rats with severe acute pancreatitis (SAP). METHODS: Rats were randomly divided into sham-operated, model control, and dexamethasone-treated groups. At 3, 6, and 12 h after operation, the expression levels of P-selectin protein in one-third of the rats in each group were observed. RESULTS: In the treated group, the expression levels of P-selectin protein in the pancreas head (at 6 h), lung (at 12 h), liver (at 3 h), and spleen (at 6 and 12 h) were significantly lower than those in the model control group (P < 0.05). Additionally, the products of the staining intensity and positive rate of P-selectin protein in liver (at 3 h), lung (at 6 and 12 h), and spleen (at 12 h) in the treated group were significantly lower than those in the model control group (P < 0.05). CONCLUSIONS: Dexamethasone can inhibit P-selectin protein expression in multiple organs of SAP rats.

Effects of Baicalin on inflammatory mediators and pancreatic acinar cell apoptosis in rats with sever acute pancreatitis.

BACKGROUND: To investigate the effects of Baicalin and Octreotide on inflammatory mediators and pancreatic acinar cells apoptosis of rats with severe acute pancreatitis (SAP). METHODS: SD rats were randomly divided into sham operated group (I group), model control group (II group), Baicalin treated group (III group) and Octreotide treated group (IV group). Each group was also divided into subgroup of 3, 6 and 12 h (n = 15). The mortality rate, ascites/body weight ratio as well as the level of endotoxin, NO and ET-1 in blood were measured. The pathological severity score of pancreas, apoptotic indexes, and expression levels of Bax and Bcl-2 proteins in each group were investigated. RESULTS: The survival rate of III and IV group has a significant difference compared with II group (P(12 h) < 0.05). The ascites volume, contents of inflammatory mediators in blood and pathological severity score of pancreas of III and IV group declined at different degrees compared to II group (P < 0.05, P < 0.01 or P < 0.001). Apoptotic index in III group was significantly higher than that in II group at 3 and 6 h (P(3, 6 h) < 0.05). Apoptotic index in IV group was significantly higher than that in II group at pancreatic tail at 6 h (P(6 h) < 0.05). Expression level of Bax in III group was significantly higher than that in II group (pancreatic head P(3 h,6 h) < 0.01, pancreatic tail P(3 h) < 0.001). CONCLUSIONS: Compared with Octreotide in the treatment of SAP, the protective mechanisms of Baicalin include reducing the excessive inflammatory mediators' release, inducing the pancreatic acinar cells apoptosis.

Vascularity and angiogenesis as predictors of growth in optic pathway/hypothalamic gliomas.

OBJECT: The authors' aim in conducting this study was to investigate retrospectively the prognostic significance of angiogenic features in optic pathway/hypothalamic gliomas (OPHGs) in children. METHODS: Patients were identified in whom a diagnosis of OPHG was made using pathological analysis at the Toronto Hospital for Sick Children between 1985 and 2002. Tumor specimens were reviewed for diagnostic accuracy and adequacy of the specimen. Sections were immunostained with factor VIII to assess microvessel density (MVD). A ratio of alpha-smooth muscle actin to factor VIII immunostaining was calculated to arrive at a vascular maturity index (VMI). Vascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) immunostaining were performed to evaluate angiogenic factors. In addition, the MIB-1 labeling index (LI) was used to assess proliferation. These factors were evaluated with respect to progression-free survival (PFS). Forty-one of 60 patients originally identified had adequate samples and follow up for inclusion in the study. Of these, eight patients had coexisting neurofibromatosis Type 1. Twenty-eight patients experienced tumor progression after the initial treatment (surgery with or without adjuvant treatment). Thirty-eight patients are still alive. A high MVD (> 21 vessels/1.2 mm2) was associated with a significantly higher rate of progression compared with a low MVD (< 21 vessels/1.2 mm2; p = 0.017). Microvessel density was also predictive of reduced PFS on multivariate analysis stratified for extent of resection (p = 0.04), and VMI as well as intensity and distribution of VEGF and VEGFR staining and the MIB-1 LI were not significantly associated with PFS. CONCLUSIONS: These findings suggest that MVD is the best current predictor of PFS in incompletely resected OPHGs. This information highlights the importance of angiogenesis in regard to low-grade gliomas.

[PPARgamma1 overexpression on caveolin-1 expression of Raw264.7 cells].

OBJECTIVE: To investigate the effect of PPARgamma1 gene overexpression on caveolin-1 mRNA and protein expressions in a murine macrophage cell line Raw264.7. METHODS: Replication-deficient recombinant adenovirus expression vector of PPARgamma1 was constructed using the AdEasy system. Raw264.7 cells were randomly treated as follows: P group (PPARgamma1 gene overexpression), T group (Troglitazone 40 micromol/L in DMSO), PT group (PPARgamma1 gene overexpression and Troglitazone) and control group. Changes of PPARgamma1 and caveolin-1 at mRNA and protein levels were investigated. RESULTS: Caveolin-1 expression can be detected by RT-PCR in Raw264.7, by immunocytochemistry method in cell and nuclear membrane but not by immunoblotting at protein level. Caveolin-1 expression at mRNA and protein levels in Raw264.7 were significantly higher in P, T and PT groups compared to control group and the expression was also significantly higher in PT group than that in P group and T group (P < 0.05). PPARgamma expression was significantly increased in PT group and P group where remained unchanged in T group compared to control group. CONCLUSION: PPARgamma1 overexpression can upregulate caveolin-1 expression in macrophages. Troglitazone upregulated caveolin-1 expression in the absence of increased PPARgamma1 expressions at mRNA and protein levels.

Differentiation and malignant suppression induced by mouse erythroid differentiation and denucleation factor on mouse erythroleukemia cells.

OBJECTIVE: To investigate the roles of mouse erythroid differentiation and denucleation factor (MEDDF), a novel factor cloned in our laboratory recently, in erythroid terminal differentiation. METHODS: Mouse erythroleukemia (MEL) cells were transfected with eukaryotic expression plasmid pcDNA-MEDDF. Then we investigated the changes on characteristics of cell growth by analyzing cells growth rate, mitotic index and colony-forming rate in semi-solid medium. The expressions of c-myc and beta-globin genes were analysed by semi-quantitative RT-PCR. RESULTS: MEL cells transfected with pcDNA-MEDDF showed significant lower growth rate, mitotic index, and colony-forming rate in semi-solid medium (P<0.01). The percentage of benzidine-positive cells was 32.8% after transfection. The expression of beta-globin in cells transfected with pcDNA-MEDDF was 3.43 times higher than that of control (MEL transfected with blank vector, pcDNA3.1), and the expression of c-myc decreased by 66.3%. CONCLUSIONS: MEDDF can induce differentiation of MEL cell and suppress its malignancy.

Equine follicle-stimulating hormone: molecular cloning of beta subunit and biological role of the asparagine-linked oligosaccharide at asparagine(56) of alpha subunit.

Equine FSH (eFSH) and eCG are members of the glycoprotein hormone family. These proteins are heterodimeric, composed of noncovalently associated alpha and beta subunits. We have previously reported that recombinant eCG has potent LH- and FSH-like activities and that the oligosaccharide at Asn(56) of the alpha subunit plays an indispensable role in expressing LH- but not FSH-like activity. In the present study, we cloned eFSH beta subunit cDNA and expressed wild-type recombinant eFSH and a partially deglycosylated mutant FSH (eFSH alpha56/beta) to investigate the biological role of the oligosaccharide at Asn(56) in FSH activity. The wild-type eFSH and eCG stimulated estradiol production in a dose-dependent manner in the primary cultures of rat granulosa cells, indicating that these equine gonadotropins have FSH activity. Partially deglycosylated eCG (eCG alpha56/beta) also stimulated estradiol production, confirming that the FSH-like activity of eCG is resistant to the removal of the N-linked oligosaccharide. Partially deglycosylated eFSH (eFSH alpha56/beta), however, did not show any FSH activity, indicating that the oligosaccharide at Asn(56) was necessary for eFSH. Thus, FSH-like activities of two gonadotropins, eCG and eFSH, are evoked through the distinct molecular mechanisms regarding the biological role of oligosaccharide at Asn(56) of the alpha subunit.