Autophagy mediated degradation of MITA/TBK1/IRF3 by a hnRNP family member attenuates interferon production in fish

HnRNP A/B belongs to the heterogeneous nuclear ribonucleoprotein (hnRNP) family and plays an important role in regulating viral protein translation and genome replication. Here, we found that overexpression of hnRNP A/B promoted Spring viremia of carp virus (SVCV) and Cyprinid herpesvirus 3 (CyHV3) replication. Further, hnRNP A/B was shown to act as a negative regulator of type I interferon (IFN) response. Mechanistically, hnRNP A/B interacted with MITA, TBK1 and IRF3 to initiate their degradation. In addition, hnRNP A/B bound to the kinase domain of TBK1, the C terminal domain of MITA and IAD domain of IRF3, and the RRM1 domain of hnRNP A/B bound to TBK1, RRM2 domain bound to IRF3 and MITA. Our study provides novel insights into the functions of hnRNP A/B in regulating host antiviral response.

GDF15 Protects Insulin-Producing Beta Cells against Pro-Inflammatory Cytokines and Metabolic Stress via Increased Deamination of Intracellular Adenosine

It has been proposed that antidiabetic drugs, such as metformin and imatinib, at least in part, promote improved glucose tolerance in type 2 diabetic patients via increased production of the inflammatory cytokine GDF15. This is supported by studies, performed in rodent cell lines and mouse models, in which the addition or production of GDF15 improved beta-cell function and survival. The aim of the present study was to determine whether human beta cells produce GDF15 in response to antidiabetic drugs and, if so, to further elucidate the mechanisms by which GDF15 modulates the function and survival of such cells. The effects and expression of GDF15 were analyzed in human insulin-producing EndoC-betaH1 cells and human islets. We observed that alpha and beta cells exhibit considerable heterogeneity in GDF15 immuno-positivity. The predominant form of GDF15 present in islet and EndoC-betaH1 cells was pro-GDF15. Imatinib, but not metformin, increased pro-GDF15 levels in EndoC-betaH1 cells. Under basal conditions, exogenous GDF15 increased human islet oxygen consumption rates. In EndoC-betaH1 cells and human islets, exogenous GDF15 partially ameliorated cytokine- or palmitate + high-glucose-induced loss of function and viability. GDF15-induced cell survival was paralleled by increased inosine levels, suggesting a more efficient disposal of intracellular adenosine. Knockdown of adenosine deaminase, the enzyme that converts adenosine to inosine, resulted in lowered inosine levels and loss of protection against cytokine- or palmitate + high-glucose-induced cell death. It is concluded that imatinib-induced GDF15 production may protect human beta cells partially against inflammatory and metabolic stress. Furthermore, it is possible that the GDF15-mediated activation of adenosine deaminase and the increased disposal of intracellular adenosine participate in protection against beta-cell death.

Lithium Intercalation into the Excitonic Insulator Candidate Ta2NiSe5

A new reduced phase derived from the excitonic insulator candidate Ta₂NiSe₅ has been synthesized via the intercalation of lithium. LiTa₂NiSe₅ crystallizes in the orthorhombic space group Pmnb (no. 62) with lattice parameters a = 3.50247(3) Å, b = 13.4053(4) Å, c = 15.7396(2) Å, and Z = 4, with an increase of the unit cell volume by 5.44(1)% compared with Ta₂NiSe₅. Significant rearrangement of the Ta-Ni-Se layers is observed, in particular a very significant relative displacement of the layers compared to the parent phase, similar to that which occurs under hydrostatic pressure. Neutron powder diffraction experiments and computational analysis confirm that Li occupies a distorted triangular prismatic site formed by Se atoms of adjacent Ta₂NiSe₅ layers with an average Li-Se bond length of 2.724(2) Å. Li-NMR experiments show a single Li environment at ambient temperature. Intercalation suppresses the distortion to monoclinic symmetry that occurs in Ta₂NiSe₅ at 328 K and that is believed to be driven by the formation of an excitonic insulating state. Magnetometry data show that the reduced phase has a smaller net diamagnetic susceptibility than Ta₂NiSe₅ due to the enhancement of the temperature-independent Pauli paramagnetism caused by the increased density of states at the Fermi level evident also from the calculations, consistent with the injection of electrons during intercalation and formation of a metallic phase.

DDX5 inhibits type I IFN production by promoting degradation of TBK1 and disrupting formation of TBK1 - TRAF3 complex

DExD/H-box helicase (DDX) 5 belongs to the DExD/H-box helicase family. DDX family members play differential roles in the regulation of innate antiviral immune response. However, whether DDX5 is involved in antiviral immunity remains unclear. In this study, we found that DDX5 serves as a negative regulator of type I interferon (IFN) response. Overexpression of DDX5 inhibited IFN production induced by Spring viremia of carp virus (SVCV) and poly(I:C) and enhanced virus replication by targeting key elements of the RLR signaling pathway (MAVS, MITA, TBK1, IRF3 and IRF7). Mechanistically, DDX5 directly interacted with TBK1 to promote its autophagy-mediated degradation. Moreover, DDX5 was shown to block the interaction between TRAF3 and TBK1, hence preventing nuclear translocation of IRF3. Together, these data shed light on the roles of DDX5 in regulating IFN response.

CLEC11A improves insulin secretion and promotes cell proliferation in human beta-cells

Beta-cell dysfunction is a hallmark of disease progression in patients with diabetes. Research has been focused on maintaining and restoring beta-cell function during diabetes development. The aims of this study were to explore the expression of C-type lectin domain containing 11A (CLEC11A), a secreted sulphated glycoprotein, in human islets and to evaluate the effects of CLEC11A on beta-cell function and proliferation in vitro. To test these hypotheses, human islets and human EndoC-βH1 cell line were used in this study. We identified that CLEC11A was expressed in beta-cells and alpha-cells in human islets but not in EndoC-βH1 cells, whereas the receptor of CLEC11A called integrin subunit alpha 11 was found in both human islets and EndoC-βH1 cells. Long-term treatment with exogenous recombinant human CLEC11A (rhCLEC11A) accentuated glucose-stimulated insulin secretion, insulin content, and proliferation from human islets and EndoC-βH1 cells, which was partially due to the accentuated expression levels of transcription factors MAFA and PDX1. However, the impaired beta-cell function and reduced mRNA expression of INS and MAFA in EndoC-βH1 cells that were caused by chronic palmitate exposure could only be partially improved by the introduction of rhCLEC11A. Based on these results, we conclude that rhCLEC11A promotes insulin secretion, insulin content, and proliferation in human beta-cells, which are associated with the accentuated expression levels of transcription factors MAFA and PDX1. CLEC11A, therefore, may provide a novel therapeutic target for maintaining beta-cell function in patients with diabetes.

Ex vivo factor VIII-modified proliferating human hepatocytes therapy for haemophilia A

Ex vivo gene manipulation in human hepatocytes is a promising therapeutic strategy in the treatment of inherited liver diseases. However, a major limitation is the lack of a highly efficient and safe genetic manipulation system for transplantable primary human hepatocytes (PHHs). Here, we reported that proliferating human hepatocytes (ProliHHs) cultured in vitro showed high susceptibility to lentivirus-mediated genetic modification and maintained cellular phenotypes after lentiviral infection. Human factor VIII expression was introduced through F8-Lentivirus-mediated transduction of ProliHHs followed by xenotransplantation into immunocompromised haemophilia A mice. We demonstrated that these F8-modified ProliHHs could effectively repopulate the mouse liver, resulting in therapeutic benefits in mouse models. Furthermore, no genotoxicity was detected in F8-modified ProliHHs using lentiviral integration site analysis. Thus, this study demonstrated, for the first time, the feasibility and safety of lentiviral modification in ProliHHs to induce the expression of coagulation factor VIII in the treatment of haemophilia A.

Association of burnout with depression in pharmacists: A network analysis

Background

Burnout and depression have overlapping symptoms, but the extent of overlap remains unclear, and the complex relationship between burnout and depression in pharmacists is rarely explored.

Methods

We investigated burnout and depression in 1,322 frontline pharmacists, and explored the complex relationship between burnout and depression in those pharmacists using network analysis.

Results

Network analysis showed that there were 5 communities. A partial overlap was found between burnout and depressive symptoms in pharmacists. The nodes MBI-6 (I have become more callous toward work since I took this job), D18 (My life is meaningless), and D10 (I get tired for no reason) had the highest expected influence value. D1 (I feel down-hearted and blue) and D14 (I have no hope for the future) were bridge symptoms connected with emotional exhaustion and reduced professional efficacy, respectively.

Conclusion

A partial overlap exists between burnout and depressive symptoms in pharmacists, mainly in the connection between the emotional exhaustion and reduced professional efficacy and the depressive symptoms. Potential core targets identified in this study may inform future prevention and intervention.

Metabolic stress-induced human beta-cell death is mediated by increased intracellular levels of adenosine

INTRODUCTION

High intracellular concentrations of adenosine and 2'-deoxyadenosine have been suggested to be an important mediator of cell death. The aim of the present study was to characterize adenosine-induced death in insulin-producing beta-cells, at control and high glucose + palmitate-induced stress conditions.

METHODS

Human insulin-producing EndoC-betaH1 cells were treated with adenosine, 2'-deoxyadenosine, inosine and high glucose + sodium palmitate, and death rates using flow cytometry were studied.

RESULTS

We observed that adenosine and the non-receptor-activating analogue 2-deoxyadenosine, but not the adenosine deamination product inosine, promoted beta-cell apoptosis at concentrations exceeding maximal adenosine-receptor stimulating concentrations. Both adenosine and inosine were efficiently taken up by EndoC-betaH1 cells, and inosine counteracted the cell death promoting effect of adenosine by competing with adenosine for uptake. Both adenosine and 2'-deoxyadenosine promptly reduced insulin-stimulated production of plasma membrane PI(3,4,5)P₃, an effect that was reversed upon wash out of adenosine. In line with this, adenosine, but not inosine, rapidly diminished Akt phosphorylation. Both pharmacological Bax inhibition and Akt activation blocked adenosine-induced beta-cell apoptosis, indicating that adenosine/2'-deoxyadenosine inhibits the PI3K/Akt/BAD anti-apoptotic pathway. High glucose + palmitate-induced cell death was paralleled by increased intracellular adenosine and inosine levels. Overexpression of adenosine deaminase-1 (ADA1) in EndoC-betaH1 cells, which increased Akt phosphorylation, prevented both adenosine-induced apoptosis and high glucose + palmitate-induced necrosis. ADA2 overexpression not only failed to protect against adenosine and high glucose + palmitate-activated cell death, but instead potentiated the apoptosis-stimulating effect of adenosine. In line with this, ADA1 overexpression increased inosine production from adenosine-exposed cells, whereas ADA2 did not. Knockdown of ADA1 resulted in increased cell death rates in response to both adenosine and high glucose + palmitate. Inhibition of miR-30e-3p binding to the ADA1 mRNA 3'-UTR promoted the opposite effects on cell death rates and reduced intracellular adenosine contents.

DISCUSSION

It is concluded that intracellular adenosine/2'-deoxyadenosine regulates negatively the PI3K pathway and is therefore an important mediator of beta-cell apoptosis. Adenosine levels are controlled, at least in part, by ADA1, and strategies to upregulate ADA1 activity, during conditions of metabolic stress, could be useful in attempts to preserve beta-cell mass in diabetes.

Construction and Interpretation of Prediction Model of Teicoplanin Trough Concentration via Machine Learning

Objective

To establish an optimal model to predict the teicoplanin trough concentrations by machine learning, and explain the feature importance in the prediction model using the SHapley Additive exPlanation (SHAP) method.

Methods

A retrospective study was performed on 279 therapeutic drug monitoring (TDM) measurements obtained from 192 patients who were treated with teicoplanin intravenously at the First Affiliated Hospital of Army Medical University from November 2017 to July 2021. This study included 27 variables, and the teicoplanin trough concentrations were considered as the target variable. The whole dataset was divided into a training group and testing group at the ratio of 8:2, and predictive performance was compared among six different algorithms. Algorithms with higher model performance (top 3) were selected to establish the ensemble prediction model and SHAP was employed to interpret the model.

Results

Three algorithms (SVR, GBRT, and RF) with high R² scores (0.676, 0.670, and 0.656, respectively) were selected to construct the ensemble model at the ratio of 6:3:1. The model with R² = 0.720, MAE = 3.628, MSE = 22.571, absolute accuracy of 83.93%, and relative accuracy of 60.71% was obtained, which performed better in model fitting and had better prediction accuracy than any single algorithm. The feature importance and direction of each variable were visually demonstrated by SHAP values, in which teicoplanin administration and renal function were the most important factors.

Conclusion

We firstly adopted a machine learning approach to predict the teicoplanin trough concentration, and interpreted the prediction model by the SHAP method, which is of great significance and value for the clinical medication guidance.

The endoplasmic reticulum-plasma membrane tethering protein TMEM24 is a regulator of cellular Ca2+ homeostasis

Endoplasmic reticulum (ER)–plasma membrane (PM) contacts are sites of lipid exchange and Ca²⁺ transport, and both lipid transport proteins and Ca²⁺ channels specifically accumulate at these locations. In pancreatic β-cells, both lipid and Ca²⁺ signaling are essential for insulin secretion. The recently characterized lipid transfer protein TMEM24 (also known as C2CD2L) dynamically localizes to ER–PM contact sites and provides phosphatidylinositol, a precursor of phosphatidylinositol-4-phosphate [PI(4)P] and phosphatidylinositol 4,5-bisphosphate [PI(4,5)P₂], to the PM. β-cells lacking TMEM24 exhibit markedly suppressed glucose-induced Ca²⁺ oscillations and insulin secretion, but the underlying mechanism is not known. We now show that TMEM24 only weakly interacts with the PM, and dissociates in response to both diacylglycerol and nanomolar elevations of cytosolic Ca²⁺. Loss of TMEM24 results in hyper-accumulation of Ca²⁺ in the ER and in excess Ca²⁺ entry into mitochondria, with resulting impairment in glucose-stimulated ATP production.

Summary: TMEM24 reversibly localizes to ER–PM contact sites and participates in the regulation of both ER and mitochondrial Ca²⁺ homeostasis and in glucose-dependent ATP production in insulin-secreting cells.

Pharmacological Inhibition of NOX4 Improves Mitochondrial Function and Survival in Human Beta-Cells

Previous studies have reported beneficial effects of NADPH oxidase 4 (NOX4) inhibition on beta-cell survival in vitro and in vivo. The mechanisms by which NOX4 inhibition protects insulin producing cells are, however, not known. The aim of the present study was to investigate the effects of a pharmacological NOX4 inhibitor (GLX7013114) on human islet and EndoC-βH1 cell mitochondrial function, and to correlate such effects with survival in islets of different size, activity, and glucose-stimulated insulin release responsiveness. We found that maximal oxygen consumption rates, but not the rates of acidification and proton leak, were increased in islets after acute NOX4 inhibition. In EndoC-βH1 cells, NOX4 inhibition increased the mitochondrial membrane potential, as estimated by JC-1 fluorescence; mitochondrial reactive oxygen species (ROS) production, as estimated by MitoSOX fluorescence; and the ATP/ADP ratio, as assessed by a bioluminescent assay. Moreover, the insulin release from EndoC-βH1 cells at a high glucose concentration increased with NOX4 inhibition. These findings were paralleled by NOX4 inhibition-induced protection against human islet cell death when challenged with high glucose and sodium palmitate. The NOX4 inhibitor protected equally well islets of different size, activity, and glucose responsiveness. We conclude that pharmacological alleviation of NOX4-induced inhibition of beta-cell mitochondria leads to increased, and not decreased, mitochondrial ROS, and this was associated with protection against cell death occurring in different types of heterogeneous islets. Thus, NOX4 inhibition or modulation may be a therapeutic strategy in type 2 diabetes that targets all types of islets.

Novel AVPR2 mutations and clinical characteristics in 28 Chinese families with congenital nephrogenic diabetes insipidus

AIMS

To investigate genotype and phenotype of congenital nephrogenic diabetes insipidus caused by AVPR2 mutations, which is rare and limitedly studied in Chinese population.

METHODS

88 subjects from 28 families with NDI in a department (Beijing, PUMCH) were screened for AVPR2 mutations. Medical records were retrospectively reviewed and characterized. Genotype and phenotype analysis was performed.

RESULTS

23 AVPR2 mutations were identified, including six novel mutations (p.Y117D, p.W208R, p.L313R, p.S127del, p.V162Sfs*30 and p.G251Pfs*96). The onset-age ranged from 1 week to 3 years. Common presentations were polydipsia and polyuria (100%) and intermittent fever (57%). 21% and 14% of patients had short stature and mental impairment. Urine SG and osmolality were decreased, while serum osmolality and sodium were high. Urological ultrasonography results showed hydronephrosis of the kidney (52%), dilation of the ureter (48%), and thickened bladder wall or increased residual urine (32%), led to intermittent urethral catheterization (7%), cystostomy (11%) and binary nephrostomy (4%). Urological defects were developed in older patients. Genotype and phenotype analysis revealed patients with non-missense mutations had higher levels of serum sodium than missense mutations.

CONCLUSION

In the first and largest case series of NDI caused by AVPR2 mutations in Chinese population, we established genetic profile and characterized clinical data, reporting six novel mutations. Further, we found genotype was associated with phenotype. This knowledge broadens genotype and phenotype spectrum of rare congenital NDI caused by AVPR2 mutations, and provides basis for studying molecular biology of AVPR2.

Imatinib protects against human beta-cell death via inhibition of mitochondrial respiration and activation of AMPK

The protein tyrosine kinase inhibitor imatinib is used in the treatment of various malignancies but may also promote beneficial effects in the treatment of diabetes. The aim of the present investigation was to characterize the mechanisms by which imatinib protects insulin producing cells. Treatment of non-obese diabetic (NOD) mice with imatinib resulted in increased beta-cell AMP-activated kinase (AMPK) phosphorylation. Imatinib activated AMPK also in vitro, resulting in decreased ribosomal protein S6 phosphorylation and protection against islet amyloid polypeptide (IAPP)-aggregation, thioredoxin interacting protein (TXNIP) up-regulation and beta-cell death. 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR) mimicked and compound C counteracted the effect of imatinib on beta-cell survival. Imatinib-induced AMPK activation was preceded by reduced glucose/pyruvate-dependent respiration, increased glycolysis rates, and a lowered ATP/AMP ratio. Imatinib augmented the fractional oxidation of fatty acids/malate, possibly via a direct interaction with the beta-oxidation enzyme enoyl coenzyme A hydratase, short chain, 1, mitochondrial (ECHS1). In non-beta cells, imatinib reduced respiratory chain complex I and II-mediated respiration and acyl-CoA carboxylase (ACC) phosphorylation, suggesting that mitochondrial effects of imatinib are not beta-cell specific. In conclusion, tyrosine kinase inhibitors modestly inhibit mitochondrial respiration, leading to AMPK activation and TXNIP down-regulation, which in turn protects against beta-cell death.

ZBED6 counteracts high-fat diet-induced glucose intolerance by maintaining beta cell area and reducing excess mitochondrial activation

AIMS/HYPOTHESIS

ZBED6 (zinc finger, BED-type containing 6) is known to regulate muscle mass by suppression of Igf2 gene transcription. In insulin-producing cell lines, ZBED6 maintains proliferative capacity at the expense of differentiation and beta cell function. The aim was to study the impact of Zbed6 knockout on beta cell function and glucose tolerance in C57BL/6 mice.

METHODS

Beta cell area and proliferation were determined in Zbed6 knockout mice using immunohistochemical analysis. Muscle and fat distribution were assessed using micro-computed tomography. Islet gene expression was assessed by RNA sequencing. Effects of a high-fat diet were analysed by glucose tolerance and insulin tolerance tests. ZBED6 was overexpressed in EndoC-βH1 cells and human islet cells using an adenoviral vector. Beta cell cell-cycle analysis, insulin release and mitochondrial function were studied in vitro using propidium iodide staining and flow cytometry, ELISA, the Seahorse technique, and the fluorescent probes JC-1 and MitoSox.

RESULTS

Islets from Zbed6 knockout mice showed lowered expression of the cell cycle gene Pttg1, decreased beta cell proliferation and decreased beta cell area, which occurred independently from ZBED6 effects on Igf2 gene expression. Zbed6 knockout mice, but not wild-type mice, developed glucose intolerance when given a high-fat diet. The high-fat diet Zbed6 knockout islets displayed upregulated expression of oxidative phosphorylation genes and genes associated with beta cell differentiation. In vitro, ZBED6 overexpression resulted in increased EndoC-βH1 cell proliferation and a reduced glucose-stimulated insulin release in human islets. ZBED6 also reduced mitochondrial JC-1 J-aggregate formation, mitochondrial oxygen consumption rates (OCR) and mitochondrial reactive oxygen species (ROS) production, both at basal and palmitate + high glucose-stimulated conditions. ZBED6-induced inhibition of OCR was not rescued by IGF2 addition. ZBED6 reduced levels of the mitochondrial regulator PPAR-γ related coactivator 1 protein (PRC) and bound its promoter/enhancer region. Knockdown of PRC resulted in a lowered OCR.

CONCLUSIONS/INTERPRETATION

It is concluded that ZBED6 is required for normal beta cell replication and also limits excessive beta cell mitochondrial activation in response to an increased functional demand. ZBED6 may act, at least in part, by restricting PRC-mediated mitochondrial activation/ROS production, which may lead to protection against beta cell dysfunction and glucose intolerance in vivo.

Altered mitochondrial metabolism in peripheral blood cells from patients with inborn errors of β-oxidation

Inborn errors of mitochondrial fatty acid oxidation (FAO), such as medium-chain acyl-CoA dehydrogenase deficiency (MCAD) and very long-chain acyl-CoA dehydrogenase deficiency (VLCAD) affects cellular function and whole-body metabolism. Carnitine uptake deficiency (CUD) disturbs the transportation of fatty acids into the mitochondria, but when treated is a mild disease without significant effects on FAO. For improved clinical care of VLCAD in particular, estimation of FAO severity could be important. We have investigated whether the oxygen consumption rate (OCR) of peripheral blood mononuclear cells (PBMCs) obtained from patients with MCAD, VLCAD, and CUD can be used to study cellular metabolism in patients with FAO defects and to determine the severity of FAO impairment. PBMCs were isolated from patients with VLCAD (n = 9), MCAD (n = 5-7), and CUD (n = 5). OCR was measured within 6-hours of venous puncture using the Seahorse XFe96. The PBMCs were exposed to glucose alone or with caprylic acid (C8:0) or palmitic acid (C16:0). OCR was significantly lower in cells from patients with β-oxidation deficiencies (MCAD and VLCAD) compared to CUD at basal conditions. When exposed to C16:0, OCR in VLCAD cells was unchanged, whereas OCR in MCAD cells increased but not to the levels observed in CUD. However, C8:0 did not increase OCR, as would be expected, in VLCAD cells. There was no clear relationship between clinical severity level and OCR. In patients with β-oxidation deficiencies, changes of mitochondrial respiration in PBMCs are detectable, which indicate that PBMCs have translational potential for studies of β-oxidation defects. However, further studies are warranted.

Impaired HMG-CoA Reductase Activity Caused by Genetic Variants or Statin Exposure: Impact on Human Adipose Tissue, β-Cells and Metabolome

Inhibition of 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase is associated with an increased risk of new-onset type 2 diabetes. We studied the association of genetic or pharmacological HMG-CoA reductase inhibition with plasma and adipose tissue (AT) metabolome and AT metabolic pathways. We also investigated the effects of statin-mediated pharmacological inhibition of HMG-CoA reductase on systemic insulin sensitivity by measuring the HOMA-IR index in subjects with or without statin therapy. The direct effects of simvastatin (20-250 nM) or its active metabolite simvastatin hydroxy acid (SA) (8-30 nM) were investigated on human adipocyte glucose uptake, lipolysis, and differentiation and pancreatic insulin secretion. We observed that the LDL-lowering HMGCR rs12916-T allele was negatively associated with plasma phosphatidylcholines and sphingomyelins, and HMGCR expression in AT was correlated with various metabolic and mitochondrial pathways. Clinical data showed that statin treatment was associated with HOMA-IR index after adjustment for age, sex, BMI, HbA1c, LDL-c levels, and diabetes status in the subjects. Supra-therapeutic concentrations of simvastatin reduced glucose uptake in adipocytes and normalized fatty acid-induced insulin hypersecretion from β-cells. Our data suggest that inhibition of HMG-CoA reductase is associated with insulin resistance. However, statins have a very mild direct effect on AT and pancreas, hence, other tissues as the liver or muscle appear to be of greater importance.

Novel AQP2 Mutations and Clinical Characteristics in Seven Chinese Families With Congenital Nephrogenic Diabetes Insipidus

OBJECTIVE

Mutations in AQP2 (aquaporin-2) lead to rare congenital nephrogenic diabetes insipidus (NDI), which has been limitedly studied in Chinese population.

METHODS

Twenty-five subjects from seven families with NDI in a department (Beijing, PUMCH) were screened for AQP2 mutations. Clinical characteristics were described and genotype-phenotype correlation analysis was performed.

RESULTS

We identified 9 AQP2 mutations in 13 patients with NDI, including 3 novel AQP2 mutations (p.G165D, p.Q255RfsTer72 and IVS3-3delC). Missense mutations were the most common mutation type, followed by splicing mutations, and frameshift mutations caused by small deletion or insertion. The onset-age in our patients was younger than 1 year old. Common manifestations included polydipsia, polyuria (7/7) and intermittent fever (6/7). Less common presentations included short stature (3/7) and mental impairment (1/7). High osmotic hypernatremia and low osmotic urine were the main biochemical features. Dilation of the urinary tract was a common complication of NDI (3/6). Level of serum sodium in NDI patients with compound het AQP2 mutations was higher than non-compound het mutations.

CONCLUSION

In the first and largest case series of NDI caused by AQP2 mutation in Chinese population, we identified 9 AQP2 mutations, including 3 novel mutations. Phenotype was found to correlate with genotypes, revealed by higher level of serum sodium in patients with compound het AQP2 mutations than non-compound het mutations. This knowledge broadens genotypic and phenotypic spectrum for rare congenital NDI and provided basis for studying molecular biology of AQP2.

Increased expression of Toll-like receptor 7 and 9 in vitiligo melanocytes: a pilot study

BACKGROUND

Toll-like receptors (TLRs) are expressed on human melanocytes, and play an important role in innate and acquired immunity. The role of TLRs in the pathogenesis of vitiligo has not been fully described.

AIM

To investigate the expression of TLRs in melanocytes from patients with vitiligo and healthy controls (HCs).

METHODS

Primary cultured vitiligo and control melanocytes were obtained from perilesional normal skin of patients with generalized vitiligo and HCs. TLRs mRNA expression in melanocytes were determined by real-time reverse transcription PCR and protein expression by western blotting. Apoptosis was analysed using an annexin V-fluorescein isothiocyanate apoptosis detection kit, and tyrosinase activity and melanin content were measured by a modified dopachrome and colorimetric method. Interleukin (IL)-6, IL-8 and soluble cell adhesion molecule (sICAM)-1 expression were measured by ELISA.

RESULTS

In vitiligo melanocytes, compared with control melanocytes, apoptosis rate, expression of TLR7 and TLR9 mRNA and protein, and production of IL-8, IL-6 and sICAM-1 were significantly increased, whereas tyrosinase activity and melanin content were significantly decreased.

CONCLUSIONS

Our results suggest that the increased expression of TLR7 and TLR9 might correlate with melanocyte dysfunction in vitiligo.

Robot-Assisted Radical Prostatectomy in a Post-Kidney Transplant Patient: An Initial Case Report in China

OBJECTIVE

Our aim was to evaluate the general applicability, feasibility, and safety of robot-assisted radical prostatectomy (RARP) in Chinese renal allograft patients for prostate cancer removal.

PATIENTS AND METHODS

A 62-year-old patient diagnosed as having biopsy-proven localized prostate cancer in March 2016 who had undergone renal transplant 12 years ago was studied. The preoperative prostate-specific antigen value was determined to be 11.82 ng/mL and the Gleason score was determined to be 3 + 3. The RARP was carried out using a transperitoneal and posterior approach with 5 ports in May 2016. The most important technique was ensuring that the transplanted kidney and ureter remained untouched during the surgery. Only the right obturator lymph nodes were dissected because the renal allograft was overlying the iliac vessels.

RESULTS

The RARP was successfully concluded following 230 minutes with an estimated blood loss of 200 mL. There were no postoperative complications. Final pathology was T2cN0M0, Gleason 3 + 3. Following catheter removal, the patient was completely continent and was discharged with no change in serum creatinine or glomerular filtration rate levels. During a 21-month follow-up, unobstructed urination, no incontinence, no biochemical recurrence, and normal kidney function were observed.

CONCLUSION

RARP in Chinese renal allograft patients is a feasible method that can be accomplished with no injuries to the transplanted kidney or ureter and is achieved with favorable oncological and functional outcomes. In addition, post-kidney transplant male patients are recommended to have routine prostate-specific antigen screening for the early detection of prostate cancer.

Palmitate-Induced Insulin Hypersecretion and Later Secretory Decline Associated with Changes in Protein Expression Patterns in Human Pancreatic Islets

In obese children with high circulating concentrations of free fatty acid palmitate, we have observed that insulin levels at fasting and in response to a glucose challenge were several times higher than in obese children with low concentrations of the fatty acid as well as in lean controls. Declining and even insufficient insulin levels were observed in obese adolescents with high levels of the fatty acid. In isolated human islets exposed to palmitate we have observed insulin hypersecretion after 2 days exposure. In contrast, insulin secretion from the islets was reduced after 7 days culture in the presence of the fatty acid. This study aims at identifying islet-related biological events potentially linked with the observed insulin hypersecretion and later secretory decline in these obese children and adolescents using the islet model. We analyzed protein expression data obtained from human islets exposed to elevated palmitate levels for 2 and 7 days by an improved methodology for statistical analysis of differentially expressed proteins. Protein profiling of islet samples by liquid chromatography-tandem mass spectrometry identified 115 differentially expressed proteins (DEPs). Several DEPs including sorcin were associated with increased glucose-stimulated insulin secretion in islets after 2 days of exposure to palmitate. Similarly, several metabolic pathways including altered protein degradation, increased autophagy, altered redox condition, and hampered insulin processing were coupled to the functional impairment of islets after 7 days of culture in the presence of palmitate. Such biological events, once validated in the islets, may give rise to novel treatment strategies aiming at normalizing insulin levels in obese children with high palmitate levels, which may reduce or even prevent obesity-related type 2 diabetes mellitus.

Mechanisms of beneficial effects of metformin on fatty acid-treated human islets

Elevated levels of palmitate accentuate glucose-stimulated insulin secretion (GSIS) after short-term and cause beta-cell dysfunction after prolonged exposure. We investigated whether metformin, the first-line oral drug for treatment of T2DM, has beneficial effects on FFA-treated human islets and the potential mechanisms behind the effects. Insulin secretion, oxygen consumption rate (OCR), AMPK activation, endoplasmic reticulum (ER) stress and apoptosis were examined in isolated human islets after exposure to elevated levels of palmitate in the absence or presence of metformin. Palmitate exposure doubled GSIS after 2 days but halved after 7 days compared with control. Inclusion of metformin during palmitate exposure normalized insulin secretion both after 2 and 7 days. After 2-day exposure to palmitate, OCR and the marker of the adaptive arm of ER stress response (sorcin) were significantly raised, whereas AMPK phosphorylation, markers of pro-apoptotic arm of ER stress response (p-EIF2α and CHOP) and apoptosis (cleaved caspase 3) were not affected. Presence of metformin during 2-day palmitate exposure normalized OCR and sorcin levels. After 7-day exposure to palmitate, OCR and sorcin were not significantly different from control level, p-AMPK was reduced and p-EIF2α, CHOP and cleaved caspase 3 were strongly upregulated. Presence of metformin during 7-day culture with palmitate normalized the level of p-AMPK, p-EIF2α, CHOP and cleaved caspase 3 but significantly increased the level of sorcin. Our study demonstrates that metformin prevents early insulin hypersecretion and later decrease in insulin secretion from palmitate-treated human islets by utilizing different mechanisms.

Identification of early biological changes in palmitate-treated isolated human islets

Background

Long-term exposure to elevated levels of free fatty acids (FFAs) is deleterious for beta-cell function and may contribute to development of type 2 diabetes mellitus (T2DM). Whereas mechanisms of impaired glucose-stimulated insulin secretion (GSIS) in FFA-treated beta-cells have been intensively studied, biological events preceding the secretory failure, when GSIS is accentuated, are poorly investigated. To identify these early events, we performed genome-wide analysis of gene expression in isolated human islets exposed to fatty acid palmitate for different time periods.

Results

Palmitate-treated human islets showed decline in beta-cell function starting from day two. Affymetrix Human Transcriptome Array 2.0 identified 903 differentially expressed genes (DEGs). Mapping of the genes onto pathways using KEGG pathway enrichment analysis predicted four islet biology-related pathways enriched prior but not after the decline of islet function and three pathways enriched both prior and after the decline of islet function. DEGs from these pathways were analyzed at the transcript level. The results propose that in palmitate-treated human islets, at early time points, protective events, including up-regulation of metallothioneins, tRNA synthetases and fatty acid-metabolising proteins, dominate over deleterious events, including inhibition of fatty acid detoxification enzymes, which contributes to the enhanced GSIS. After prolonged exposure of islets to palmitate, the protective events are outweighed by the deleterious events, which leads to impaired GSIS.

Conclusions

The study identifies temporal order between different cellular events, which either promote or protect from beta-cell failure. The sequence of these events should be considered when developing strategies for prevention and treatment of the disease.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5008-z) contains supplementary material, which is available to authorized users.

[Longterm surgery outcome of Möbius syndrome]

Objective: To investigate clinical features and the long-term surgery results of Möbius syndrome patients. Methods: This investigation presents a retrospective study of Möbius syndrome in 7 children we found since 2009. All 7 patients had MRI scan, ocular alignment in primary position, the limitation of versions and ductions and forced duction under general anesthesia. Early surgery is done to the 7 esotropia children. The pre-operative and post-operative outcomes, including the ocular alignment, deviation measurements and ocular rotations, were evaluated and compared. Results: MRI showed absence of uni- or bilateral CN6 and CN7 in all 7 patients. All 7 patients underwent extra large recession of medial rectus at the first surgery, (6.17±1.47) mm/eye. Variation of ocular deviation in the primary position within 6 months postoperatively in all patients, demonstrating that strabismus surgical stabilization needs time. Three patients with esotropia deviation≥40° preoperative were under corrected and needed the secondary operations. The average deviation in the primary position was +35.00°±16.58° before surgery and +2.14°±5.67° after surgery(t=6.040, P<0.01). The abduction in affected eye is limited both pre and postoperatively and a smaller limitation of adduction after surgery. Conclusions: Möbius syndrome has been classified to congenital cranial dysinnervation disorders (CCDDs). We recommend MR recession as the first surgical choice because of the lack of abduction ability. Longterm surgical results were considered satisfactory, improving patient self-esteem and the parent satisfaction. (Chin J Ophthalmol, 2017, 53: 897-902).

Simulation of dissolution in porous media in three dimensions with lattice Boltzmann, finite-volume, and surface-rescaling methods

We present a pore-scale dissolution model for the simulation of reactive transport in complex porous media such as those encountered in carbon-storage injection processes. We couple a lattice Boltzmann model for flow calculation with a finite-volume method for solving chemical transport equations, and allow the computational grid to change as mineral surfaces are dissolved according to first-order reaction kinetics. We appraise this scheme for use with high Péclet number flows in three-dimensional geometries and show how the popular first-order convection scheme is affected by severe numerical diffusion when grid Péclet numbers exceed unity, and confirm that this can be overcome relatively easily by using a second-order method in conjunction with a flux-limiter function. We then propose a surface rescaling method which uses parabolic elements to counteract errors in surface area exposed by the Cartesian grid and avoid the use of more complex embedded surface methods when surface reaction kinetics are incorporated. Finally, we compute dissolution in an image of a real porous limestone rock sample injected with HCl for different Péclet numbers and obtain dissolution patterns in concordance with theory and experimental observation. A low injection flow rate was shown to lead to erosion of the pore space concentrated at the face of the rock, whereas a high flow rate leads to wormhole formation.

Identification of five novel arginine vasopressin gene mutations in patients with familial neurohypophyseal diabetes insipidus

Familial neurohypophyseal diabetes insipidus (FNDI) is a genetic disorder presenting with polyuria and polydipsia and is caused by mutations in the arginine vasopressin-neurophysin II (AVP-NPII) gene. The clinical manifestations of this disorder vary greatly depending on different mutations. The present study reports the genetic, clinical and biochemical characteristics of patients with FNDI caused by five novel mutations. Ten patients encompassing two pedigrees and four individual cases diagnosed with FNDI were included. Biochemical markers and magnetic resonance imaging (MRI) were evaluated and genomic DNA was sequenced. The results revealed that age at onset ranged from 1.0 to 11.0 years. Daily urine volumes ranged from 2.0 to 12.0 liters. One patient had mental retardation and three patients had puberty retardation; one patient had nausea, vomiting and mental retardation; and two patients had fever. Treatments, if given, included desmopressin and vasopressin tannate. Posterior pituitary T1-weighted MRI high-intensity signals were absent in two cases and present in four cases. Sequencing revealed five novel mutations in the AVP-NPII gene. On the whole, the findings of the present study indicate that FNDI exhibits different clinical manifestations and a diverse age at onset. Posterior pituitary MRI does not provide a definite diagnosis of FNDI. We also identified five novel AVP-NPII mutations. Thus, an enhanced understanding of FNDI pathogenesis may provide a basis for the development of presymptomatic FNDI diagnotic tools.

Altered Plasma Levels of Glucagon, GLP-1 and Glicentin During OGTT in Adolescents With Obesity and Type 2 Diabetes

CONTEXT

Proglucagon-derived hormones are important for glucose metabolism, but little is known about them in pediatric obesity and type 2 diabetes mellitus (T2DM).

OBJECTIVE

Fasting and postprandial levels of proglucagon-derived peptides glucagon, GLP-1, and glicentin in adolescents with obesity across the glucose tolerance spectrum were investigated.

DESIGN

This was a cross-sectional study with plasma hormone levels quantified at fasting and during an oral glucose tolerance test (OGTT).

SETTING

This study took place in a pediatric obesity clinic at Uppsala University Hospital, Sweden.

PATIENTS AND PARTICIPANTS

Adolescents with obesity, age 10-18 years, with normal glucose tolerance (NGT, n = 23), impaired glucose tolerance (IGT, n = 19), or T2DM (n = 4) and age-matched lean adolescents (n = 19) were included.

MAIN OUTCOME MEASURES

Outcome measures were fasting and OGTT plasma levels of insulin, glucagon, active GLP-1, and glicentin.

RESULTS

Adolescents with obesity and IGT had lower fasting GLP-1 and glicentin levels than those with NGT (0.25 vs 0.53 pM, P < .05; 18.2 vs 23.6 pM, P < .01) and adolescents with obesity and T2DM had higher fasting glucagon levels (18.1 vs 10.1 pM, P < .01) than those with NGT. During OGTT, glicentin/glucagon ratios were lower in adolescents with obesity and NGT than in lean adolescents (P < .01) and even lower in IGT (P < .05) and T2DM (P < .001).

CONCLUSIONS

Obese adolescents with IGT have lowered fasting GLP-1 and glicentin levels. In T2DM, fasting glucagon levels are elevated, whereas GLP-1 and glicentin levels are maintained low. During OGTT, adolescents with obesity have more products of pancreatically than intestinally cleaved proglucagon (ie, more glucagon and less GLP-1) in the plasma. This shift becomes more pronounced when glucose tolerance deteriorates.

Role of the AMP kinase in cytokine-induced human EndoC-βH1 cell death

The aim of the present investigation was to delineate cytokine-induced signaling and death using the EndoC-βH1 cells as a model for primary human beta-cells. The cytokines IL-1β and IFN-γ induced a rapid and transient activation of NF-κB, STAT-1, ERK, JNK and eIF-2α signaling. The EndoC-βH1 cells died rapidly when exposed to IL-1β + IFN-γ, and this occurred also in the presence of the actinomycin D. Inhibition of NF-κB and STAT-1 did not protect against cell death, nor did the cytokines activate iNOS expression. Instead, cytokines promoted a rapid decrease in EndoC-βH1 cell respiration and ATP levels, and we observed protection by the AMPK activator AICAR against cytokine-induced cell death. It is concluded that EndoC-βH1 cell death can be prevented by AMPK activation, which suggests a role for ATP depletion in cytokine-induced human beta-cell death.

The synergistic interaction between the calcineurin B subunit and IFN-γ enhances macrophage antitumor activity

Macrophages are involved in tumor growth and progression. They infiltrate into tumors and cause inflammation, which creates a microenvironment favoring tumor growth and metastasis. However, certain stimuli may induce macrophages to act as tumor terminators. Here we report that the calcineurin B subunit (CnB) synergizes with IFN-γ to make macrophages highly cytotoxic to cancer cells. Furthermore, CnB and IFN-γ act synergistically to polarize mouse tumor-associated macrophages, as well as human monocyte-derived macrophages to an M1-like phenotype. This synergy is mediated by the crosstalk between CnB-engaged integrin αM-p38 MAPK signaling and IFN-γ-initiated p38/PKC-δ/Jak2 signaling. Interestingly, the signal transducer and activator of transcription 1 (STAT1) is a key factor that orchestrates the synergy of CnB and IFN-γ, and the phosphorylation status at Ser727 and Tyr701 of STAT1 is directly regulated by CnB and IFN-γ.

Novel autosomal recessive gene mutations in aquaporin-2 in two Chinese congenital nephrogenic diabetes insipidus pedigrees

Recent evidence has linked novel mutations in the arginine vasopressin receptor 2 gene (AVPR2) and aquaporin-2 gene (AQP2) present in Southeast Asian populations to congenital nephrogenic diabetes insipidus (NDI). To investigate mutations in 2 distinct Chinese pedigrees with NDI patients, clinical data, laboratory findings, and genomic DNA sequences from peripheral blood leukocytes were analyzed in two 5.5- and 8-year-old boys (proband 1 and 2, respectively) and their first-degree relatives. Water intake, urinary volume, body weight and medication use were recorded. Mutations in coding regions and intron-exon borders of both AQP2 and AVPR2 gene were sequenced. Three mutations in AQP2 were detected, including previously reported heterozygous frameshift mutation (c.127_128delCA, p.Gln43Aspfs ×63) inherited from the mother, a novel frameshift mutation (c.501_502insC, p.Val168Argfs ×30, inherited from the father) in proband 1 and a novel missense mutation (c. 643G>A, p. G215S), inherited from both parents in proband 2. In family 2 both parents and one sister were heterozygous carriers of the novel missense mutation. Neither pedigree exhibited mutation in the AVPR2 gene. The patient with truncated AQP2 may present with much more severe NDI manifestations. Identification of these novel AQP2 gene mutations expands the AQP2 genotypic spectrum and may contribute to etiological diagnosis and genetic counseling.

Expression of Rap1GAP in human myeloid disease following microarray selection

To find the underlying causes of primary myelodysplastic syndrome (MDS), the gene expression profiling of both CD34+ cells and bone marrow mononuclear cells from MDS patients was performed using oligonucleotide microarray and cDNA microarrays, respectively. Several candidate genes which were differentially expressed in MDS patients versus normal controls were selected and confirmed in expanding samples by quantitative real-time reverse transcription-polymerase chain reaction after clustering and bioinformatics analysis. one of these genes, RAP1GAP, was found to be expressed at a significantly higher level in patients with MDS in comparison with those suffering from other hematopoietic diseases including leukemia (P < 0.01). We propose that over-expression of RAP1GAP gene may play a role in the pathogenesis of MDS.

[In vitro effect of lovastatin on NB4 promyelocytic leukemia cells]

OBJECTIVE

To explore the effect of lovastatin(LOV) on cell growth, apoptosis and differentiation of NB4 cells and elucidate some of the possible mechanism.

METHODS

Cell proliferation and viability were analyzed by MTT assay and trypan blue exclusion assay, cell differentiation by NBT reduction. Cell morphological examination, DNA electrophoresis, flow cytometry, TUNEL in situ hybridization and semi-quantitative RT-PCR were performed to determine cell apoptosis. H,K,N-ras gene expression was investigated by RT-PCR and p21Ras protein expression by flow cytometry.

RESULTS

1. LOV inhibited the proliferation of NB4 cells with a lC50 of 12.59 mumol/L. 2. LOV induced apoptosis of NB4 cells, affected the cell cycle progression and arrested NB4 cells in G1/S phase. Bcl-2 mRNA was down-regulated by LOV in a time-dependent manner. 3. LOV could not induce the differentiation of NB4. 4. LOV did not increase the expression of H,K,N-ras mRNA, but decrease p21Ras protein expression on the cellular membrane.

CONCLUSION

LOV can inhibit proliferation, induce apoptosis and interfere with cell cycle progression, but not induce differentiation of NB4. Inhibition of p21Ras protein isoprenylation is considered to be the major mechanism of LOV affecting NB4 cells.

[Effects of mixed cord blood serum on long-term culture of bone marrow hematopoietic cells]

AIM

To demonstrate the role of cord blood serum on dte long-term culture of bone marrow and provide the experimental foundation for its clinical use, the response of the bone marrow mononuclear cells to the mixed cord blood serum was investigated on the basis of Dexter culture system.

METHODS

In ten samples of human bone marrow, 1 x 10(6) bone marrow mononuclear cells were planted onto the stromal cells layer and cultured for five weeks, Cobblestone area forming cells (CAFC), long-term colony-initiation cells (LTC-IC), and the nuclear cells count in the supernatant was observed.

RESULTS

CAFC, LTC-IC were 37.1 +/- 12.4/(ml. well), 40.9 +/- 10.6/(ml. well) respectively in control group. The accounts were increased in the group of 10% MCBS, although it was less than that in mixed cytokines group. When combined with cytokines, 10% MCBS enhanced the growth of CAFC and LTC-IC obviously compared with that when cytokines were used alone. 20% MCBS failed to substitute the role of mixed cytokines plus fatal calf serum on the expansion of CAFC, LTC-IC and NCC.

CONCLUSION

MCBS have the activity of stimulation for hematopoietic stem cells, which is analogous to SCF, IL-3, etc. Its nature and concentration remain to be investigated extensively.

[Adjustable interatrial communication in management of severe congenital heart disease]

OBJECTIVE

To assess the use of adjustable interatrial communication in patient with severe congenital heart disease undergoing open heart surgery.

METHODS

From February 1998 to June 1999, 13 patients with severe and complex congenital heart disease underwent open heart surgery. Seven patients underwent total cavopulmonary connection, five patients repair of Ebstein's anomaly, and one patient right atrial-pulmonary connection. Adjustable interatrial communication was made in all patients. Four patients had the communication closed at the time of operation, 4 patients had the communication opened at the time of operation, and 5 patients had the communication adjusted and closed postoperatively.

RESULTS

All patients had a smooth postoperative process. There were no postoperative death and no severe postoperative complications.

CONCLUSION

Adjustable interatrial communication for the patients undergoing modified Fontan procedure or correction of Ebstein's anomaly may be advantageous.

Expression of the human multidrug resistance gene mdr1 in leukemic cells and its application in studying P-glycoprotein antagonists

OBJECTIVE

To investigate the retrovirus-mediated transfer and expression of multidrug resistance gene (mdr1) in hematopoietic cells and to develop a model for studying the possible reversal of the MDR-mediated phenotype.

METHODS

A retroviral vector HaMDR expressing the human mdr1 gene was packaged by PA317 cells with a titer of up to 8.5 x 10(5) CFU/ml. K562 leukemia cells were infected with MDR retrovirus, and transfectant K562/MDR cells were generated. The integration and expression of the exogenous mdr1 gene in K562/MDR cells were determined by polymerase chain reaction and flow cytometry. The reversal ability of P-glycoprotein (P-gp) antagonists was analyzed by in vitro drug sensitivity, accumulation and efflux of rhodamine 123 (Rh123) in this model.

RESULTS

Transduction with amphotropic MDR retrovirus resulted in integration and expression of the mdr1 gene in the resistant cells, where an aberrant splicing transcript of the mdr1 gene was found. The K562/MDR cells displayed a classic MDR phenotype with a 41-78 fold resistance to vincristine and colchicine in comparison with parental K562 cells. The drug sensitivity of K562/MDR cells to vincristine can be completely restored by cyclosporin A (CsA, 2 mg/L) and Cremophor EL (CRE 132 mg/L), either individually or in combination (P < 0.05). CsA (3 mg/L) can block the efflux pump function of P-gp shown by the significantly increased accumulation and efflux reduction of Rh123 in K562/MDR cells.

CONCLUSIONS

Retroviral vector HaMDR allows transfection with high-level expression of the mdr1 gene in human myeloid progenitor cells K562. The transfected K562/MDR provides a simple, sensitive model for developing antagonists of P-gp and studying their mechanism of action.

[Study on the differentiation and apoptosis of promyelocytic leukemia cells induced by tributyrin]

OBJECTIVE

To investigate the differentiation of NB4 and MR2 cells induced by tributyrin (TB) in combination with different doses of all-trans retinoic acid (ATRA) and to see if TB can induce apoptosis of NB4 and MR2 cells.

METHODS

Cell differentiation was analyzed by NBT reduction and CD(11b), CD(14) and CD(33), apoptosis by morphology, DNA electrophoresis, flow cytometry (FCM) and TUNEL in situ hybridization, bcl-2 expression by reverse transcriptase polymerase chain reaction.

RESULTS

0.2 mmol/L TB in combination with different doses of ATRA could potentiate the differentiation of NB4 cells induced by ATRA alone. No MR2 cell could be markedly induced by ATRA alone or in combination with TB. Treated with 1 mmol/L TB for 24 hours NB4 and MR2 cells exhibited a morphological characteristic of apoptosis and typical DNA ladder on gel electrophoresis. FCM analysis showed that TB could interfere with cell cycle in NB4 and MR2 cells, with a similar ratio of sub-G(1) in both cell lines. TUNEL in situ hybridization confirmed these results. Further study showed that TB could gradually down-regulated bcl-2 expression.

CONCLUSION

TB exerts synergetic effect on ATRA-induced differentiation and induces apoptosis in promyelocytic leukemic cells.

[Surgical treatment of ventricular septal defect in infants: report of 230 cases]

OBJECTIVE

To review the experience of surgical treatment of ventricular septal defect (VSD) in infants.

METHODS

230 infants with VSD of less than 3 years old underwent surgical repair from Feb. 1990 to Dec. 1997. Their ages ranged from 3 to 36 months. Their weight was 3.2 to 15.5 kg. The number of patients with perimembranous VSD was 192, and that of subpulmonary VSD 36. Two patients had multiple VSDs. 150 patients (65.2%) had moderate or severe pulmonary hypertension before operation.

RESULTS

Thirteen patients died during hospitalization period, with a hospital mortality of 5.65%. The main causes of death were pulmonary hypertensive crisis and arrhythmia. The leading complications were pulmonary infections, arrhythmia and pulmonary hypertensive crisis.

CONCLUSIONS

Surgical treatment of VSD in infancy may have a satisfactory outcome, it standardized surgical techniques and the improved perioperative management are used.

[Efficient gene transfer mediated by retrovirus vector in leukemic cells]

OBJECTIVE

To establish an efficient and safe gene transfer system mediated by retrovirus for providing an experimental basis of gene therapy in human leukemia.

METHODS

The retrovirus vector pLXSN, carrying the NeoR, was transferred into amphotropic packaging cell line GP + envAm12 by liposome method or by transduction. Retrovirus with higher titer was used to infect human leukemic cell lines NB4, U937 and THP-1. The efficiency of gene transduction was tesed on colonies formed by K562 cells after gene transduction.

RESULTS

The titer of DOSPER liposome transfected GP + envAm12 pool on NIH3T3 cells was 8.0 x 10(5) CFU/ml while that of producer pool infected with mouse retrovirus was 1.6 x 10(7) CFU/ml. Integration of NeoR into human leukemic cells was confirmed by PCR. By both nested PCR and NeoR rescue assay, no helper virus was found. NeoR gene transfer with the efficiency as high as 93.3 to 100% in K562 cells was verified by semi-nested PCR on the colonies after seven days' culture.

CONCLUSION

The efficiency and safety of the gene transfer system may provide an optimal experimental system in gene therapy for human leukemia.