The association between glycated albumin, glycohemoglobin, and glycated albumin to glycohemoglobin ratio in diabetic retinopathy of prediabetes.

Prediabetes increased risk of diabetes and diabetes-related macrovascular and microvascular complication. Glycohemoglobin (HbA1c ) is clinically used as the gold standard for glycemic control of diabetes. Glycated albumin (GA) is an early Amadori-type glycation protein between glucose and serum albumin, which changes in a shorter period of time than HbA1c and is superior to HbA1c in reflecting fluctuations in blood glucose. In this study, we aim to assess the predictive value of GA and glycohemoglobin (HbA1c) on a progression of diabetic retinopathy (DR) in prediabetic patients in Taiwan. This study was conducted at the outpatient department of a regional hospital in Southern Taiwan, and recruited 291 patients with prediabetes from January 2016 to February 2017. Blood and urine samples were obtained from all patients after fasting for 12 hours within 1 month of enrollment. The mean age is 62.5 ± 13.0 years and there are 161 males and 130 females. A total of 24.1% of patients have DR. The average value of GA and HbA1c are 14.6% ± 2.8% and 6.0% ± 0.4%, respectively. Old age, male, high systolic blood pressure, high HbA1C , and low total cholesterol are significantly associated with DR in patients with pre-DM. Therefore, in the prediabetic populations, high HbA1C, but not GA nor GA/HbA1C ratio, is significantly associated with DR.

GREATER LOW-DENSITY LIPOPROTEIN CHOLESTEROL VARIABILITY INCREASES THE RISK OF CARDIOVASCULAR EVENTS IN PATIENTS WITH TYPE 2 DIABETES MELLITUS.

Objective: Variability in lipid levels has been associated with poor cardiovascular outcomes in patients with coronary artery disease. The aim of this study was to investigate whether low-density lipoprotein cholesterol (LDLC) variability can be used to predict cardiovascular events in patients with type 2 diabetes mellitus (DM). Methods: A total of 5,354 patients with type 2 DM were enrolled in this study. Cardiovascular events including peripheral arterial disease, coronary artery disease, stroke, and cardiovascular death were defined as the study endpoints, and standard deviations of lipid levels were used to define intra-individual lipid variability. Results: Univariate Cox proportional hazards analysis showed that LDL-C standard deviation (hazard ratio [HR] = 1.016; 95% confidence interval [CI] = 1.006 to 1.022; P<.001) was associated with a higher risk of cardiovascular events. Multivariate Cox proportional hazards analysis showed that an increase in LDL-C standard deviation significantly increased the risk of cardiovascular events (HR = 1.063; 95% CI = 1.025 to 1.102; P = .01). Kaplan-Meier analysis of cardiovascular event-free survival showed that the patients in tertiles 2 and 3 of the standard deviation of LDL-C had worse cardiovascular event-free survival compared to those in tertile 1. Conclusion: Variability in LDL-C could predict cardiovascular events in the patients with type 2 DM in this study. Abbreviations: CAD = coronary artery disease; CI = confidence interval; CVD = cardiovascular disease; DM = diabetes mellitus; eGFR = estimated glomerular filtration rate; HbA1c = glycosylated hemoglobin; HDL-C = high-density lipoprotein cholesterol; HR = hazard ratio; KMUHRD = Kaohsiung Medical University Hospital Research Database; LDL-C = low-density lipoprotein cholesterol; SD = standard deviation; UACR = urine albumin to creatinine ratio.

Fluid Shear Stress Induces Cell Cycle Arrest in Human Urinary Bladder Transitional Cell Carcinoma Through Bone Morphogenetic Protein Receptor-Smad1/5 Pathway.

INTRODUCTION: Mechanical force generated from the interstitial fluid flow inside and surrounding tissue has been known to play a significant role in cancer pathophysiology. In this study, we aimed to investigate the role of laminar shear stress (LSS) in modulating the cell cycle of human bladder transitional carcinoma (BFTC-905) cells which are frequently stimulated by not only the interstitial fluid flow, but also the urine flow transported from kidney to bladder in the urinary tract. METHODS: The BFTC-905 cells were subjected to 0-12 dynes cm-2 LSS for 1, 4, 8, or 12 h, respectively, followed by cellular and molecular assays for investigations of cell cycle regulation protein expressions, cell growth rates, and the potential mechanism. RESULTS: The results showed that the LSS with ≥ 8 dynes cm-2 for ≥ 8 h significantly increased protein expressions of cyclin B1, Wee1, p21, and p-CDK1(Tyr15) (p < 0.05 for each), but conversely decreased protein expressions of cyclin A2, D1, E1, and CDK-1, -2, -4, and -6 (p < 0.05 for each) in the BFTC-905 cells, indicating that a G2/M cell cycle arrest was obtained after shearing stimulation. Furthermore, our data demonstrated that the LSS-induced G2/M arrest and the corresponding changes in cell cycle regulatory protein expressions were modulated by bone morphogenetic protein (BMP) receptor-Smad1/5 signaling pathway. CONCLUSIONS: Our findings provided evidences for the effect of mechanical microenvironment on urothelial cancer pathobiology and generated insights into mechanism of LSS-regulated bladder tumor cell cycle.

A microfluidic chip for formation and collection of emulsion droplets utilizing active pneumatic micro-choppers and micro-switches.

The formation of emulsification droplets is crucial for many industrial applications. This paper reports a new microfluidic chip capable of formation and collection of micro-droplets in liquids for emulsion applications. This microfluidic chip comprising microchannels, a micro-chopper and a micro-switch was fabricated by using micro-electro-mechanical-systems (MEMS) technology. The microfluidic chip can generate uniform droplets with tunable sizes by using combination of flow-focusing and liquid-chopping techniques. The droplet size can be actively fine-tuned by controlling either the relative sheath/sample flow velocity ratios or the chopping frequency. The generated droplets can be then sorted to a specific collection area utilizing an active pneumatic micro-switch formed with three micro-valves. Experimental data showed that the olive oil and sodium-alginate (Na-alginate) droplets with diameters ranging from 3 mum to 70 mum with a variation less than 14% is successfully generated and collected. The development of this microfluidic system can be promising for emulsion, drug delivery and nano-medicine applications.

Avian influenza virus hemagglutinin display on baculovirus envelope: cytoplasmic domain affects virus properties and vaccine potential.

Hemagglutinin (HA) is the major immunogen on the envelope of avian influenza virus (AIV). Therefore we constructed two recombinant baculoviruses: Bac-HA, expressing histidine-tagged HA with the cytoplasmic domain (CTD) derived from HA, and Bac-HA64, expressing histidine-tagged HA with the CTD derived from baculovirus envelope protein gp64. After infection, HA with either CTD was expressed and anchored on the plasma membrane of Sf-9 cells, as revealed by confocal microscopy. Immunogold electron microscopy demonstrated that both Bac-HA and Bac-HA64 displayed HA on the viral surface. However, analyses of purified viruses revealed that significantly more HA was incorporated into Bac-HA64 than into Bac-HA. In comparison with Bac-HA, Bac-HA64 significantly improved the gene delivery and transgene expression in mammalian cells, as determined by quantitative real-time polymerase chain reaction and flow cytometry. Bac-HA64 elicited significantly higher hemagglutination inhibition titers in mouse models than Bac-HA and the negative controls. These data collectively confirmed that the gp64 CTD, in comparison with HA CTD, resulted in more efficient HA incorporation into baculovirus, more efficient transgene delivery and expression, and elevated immunogenicity. This is the first report demonstrating the potential of HA-pseudotyped baculovirus as an avian influenza vaccine and that the choice of CTD tremendously affects baculovirus properties and vaccine efficacy.

Accelerated induction of apoptosis in insect cells by baculovirus-expressed SARS-CoV membrane protein.

It has been shown that severe acute respiratory syndrome-associated coronavirus (SARS-CoV) 3a and 7a proteins, but not membrane (M) protein, induce apoptosis in mammalian cells. Upon expression of SARS-CoV M protein using the baculovirus/insect cell expression system, however, we found that the expressed M protein triggered accelerated apoptosis in insect cells, as characterized by rapid cell death, elevated cytotoxicity, cell shrinkage, nuclear condensation and DNA fragmentation. Conversely, the M protein expressed in mammalian cells did not induce apoptosis. This is the first report describing the induction of apoptosis by SARS-CoV M protein in animal cells and possible implications are discussed.

Efficient expression of histidine-tagged large hepatitis delta antigen in baculovirus-transduced baby hamster kidney cells.

AIM: To study the baculovirus/mammalian cell system for efficient expression of functional large hepatitis delta antigen (L-HDAg). METHODS: A recombinant baculovirus expressing histidine-tagged L-HDAg (L-HDAgH) was constructed to transduce baby hamster kidney (BHK) cells by a simplified transduction protocol. RESULTS: The recombinant baculovirus transduced BHK cells with efficiencies higher than 90% as determined by flow cytometry. The expression level was significantly higher than that obtained by plasmid transfection and was further enhanced 3-fold to around 19 pg/cell by the addition of 10 mmol/L sodium butyrate. Importantly, the expressed L-HDAgH was localized to the cell nucleus and correctly isoprenylated as determined by immunofluorescence labeling and confocal microscopy. Moreover, L-HDAgH interacted with hepatitis B surface antigen to form virus-like particles. CONCLUSION: The fusion with histidine tags as well as overexpression of L-HDAgH in the baculovirus-transduced BHK cells does not impair the biological functions. Taken together, the baculovirus/mammalian cell system offers an attractive alternative for high level expression of L-HDAgH or other proteins that require extensive post-translational modifications.

Expression, purification and characterization of enterovirus-71 virus-like particles.

AIM: Enterovirus 71 (EV71) has been implicated as the etiological agent responsible for the recent outbreaks of hand, foot and mouth disease associated with severe neurological diseases in the Asia-Pacific region. METHODS: The assembly process was hypothesized to occur via an orchestrated proteolytic processing of the P1 precursor by the viral protease 3CD. To test this hypothesis, we constructed 3 recombinant baculoviruses: Bac-P1 expressing P1; Bac-3CD expressing 3CD; and Bac-P1-3CD co-expressing P1 and 3CD. RESULTS: Both single infection by Bac-P1-3CD and co-infection by Bac-P1 and Bac-3CD resulted in correct cleavage of P1 to yield individual proteins VP0, VP1 and VP3, while the former approach yielded higher VLP production. In the cells, the structural proteins self-assembled into clusters of virus-like particles (VLP) resembling the authentic EV71 particle aggregates. After ultracentrifugation purification, the dispersed VLPs were indistinguishable from the authentic virus in size, appearance, composition and surface epitopes, as determined by SDS-PAGE, Western blot, transmission electron microscopy and immunogold labeling. CONCLUSION: Our data, for the first time, suggest that in insect cells EV71 structural proteins adopt a processing and assembly pathway similar to poliovirus assembly. The preservation of particle morphology and composition suggest that the VLP may be a valuable vaccine candidate to prevent EV71 epidemics.

Determination of the baculovirus transducing titer in mammalian cells.

Baculovirus has emerged as a promising vector for in vivo or ex vivo gene therapy. To date, the infectious titer and multiplicity of infection (MOI) based on the ability of baculovirus to infect insect cells are commonly adopted to indicate the virus dosage. However, the infectious titer and MOI do not reliably represent the baculovirus transducing ability, making the comparison of baculovirus-mediated gene transfer difficult. To determine the baculovirus transducing ability more rapidly and reliably, we developed a protocol to evaluate the transducing titers of baculovirus stocks. The virus was diluted twofold serially and used to transduce HeLa cells. The resultant transduction efficiencies were measured by flow cytometry for the calculation of transducing titers. Compared to the infectious titer, the determination of transducing titer is more reproducible as the standard deviations among measurements are smaller. Also, the transducing titers can be obtained in 24 h, which is significantly faster as opposed to 4-7 days to obtain the infectious titer. More importantly, we demonstrated that baculoviruses with higher transducing titers could transduce cells at higher efficiency and yield stronger and longer transgene expression, confirming that the transducing titer was representative of the baculovirus transducing ability. This finding is particularly significant for ex vivo gene delivery whereby unconcentrated viruses are used for transduction and long-term transgene expression is desired. In this regard, our titration protocol provides a simple, fast, and reliable measure to evaluate the quality of virus stocks during virus production and purification, and is helpful to predict the performance of vector supernatants and ensure reproducible gene delivery experiments.

Expression and purification of N and E proteins from severe acute respiratory syndrome (SARS)-associated coronavirus: a comparative study.

Histidine-tagged N (rNH) and E (rEH) proteins of Severe Acute Respiratory Syndrome (SARS)-coronovirus were expressed in the baculovirus/insect cell system and purified by immobilized metal affinity chromatography. rNH and rEH proteins differed markedly with respect to expression levels, cell death kinetics and subcellular localizations that led to different extraction and purification schemes. The features of both proteins are compared and the potential applications of purified rNH and rEH are discussed.

Baculovirus-mediated production of HDV-like particles in BHK cells using a novel oscillating bioreactor.

We have recently demonstrated the assembly of hepatitis delta virus-like particles (HDV VLP) by co-transducing hepatoma cells using two recombinant baculoviruses, one encoding hepatitis B surface antigen (HBsAg), and one encoding large delta antigen (L-HDAg). In this study, we further demonstrated the assembly and secretion of VLP in other mammalian cells. The assembly efficiency varied depending on cell lines, the baculovirus constructs and the relative dosage of both recombinant viruses. The co-transduction of BHK cells led to the formation of VLPs resembling authentic virions in size and appearance. The production process was transferred to a novel oscillating packed bed bioreactor, BelloCell, in which the transduction efficiency was up to approximately 90% for a high cell density of 1.5 x 10(7) cells/cm(3) bed and a total yield of 427 microg based on HBsAg in the VLP (harvested from 940 ml medium) was obtained. The particle yield corresponded to an average volumetric yield of 454 ngml(-1) and a specific yield of 285 microg/10(9) cells, and is significantly superior to that can be obtained by the commonly employed transfection method. The combination of baculovirus transduction and BelloCell reactor, thus, may represent a simple and efficient approach for the production of HDV VLP and viral vectors.