[Optimization of the experimental condition on separating lipoproteins by self-constructed asymmetrical flow field-flow fractionation]

OBJECTIVE

To analyze and characterize the separation effectiveness of self-constructed asymmetrical flow field-flow fractionation system on proteins and lipoproteins, to achieve the optimization of the experimental conditions when separating lipoproteins by orthogonal design test and to investigate the carrier viscosity's influence on separation effectiveness.

METHODS

The evaluation of asymmetrical flow field-flow fractionation separation capacity was conducted by using two standard proteins (carbonic anhydrase and thyroglobulin). Under the optimized separation conditions of carbonic anhydrase and thyroglobulin, the channel actual thickness (after assembling, the actual thickness of separation channel was less than initial thickness) was calculated by the analytes' elution time based on the hydrokinetic theory. With orthogonal design test the optimized experimental conditions were studied and statistical analysis was carried on to find out the factors with statistical significance which needed further exploration.

RESULTS

According to the hydrodynamics principle and Stoke's function, the channel actual thickness was measured to be 164 μm by separating the two standard proteins, carbonic anhydrase and thyroglobulin, under proper experimental conditions. By the optimization based on orthogonal design test, base-line separation (the resolution had to be higher than 1.50) was achieved. The resolutions of the two experiments were 1.61 and 1.58. According to previous study/ pre-study and supporting theory, in the orthogonal design test, the total 5 factors were integrated for comprehensive investigation: the total flow rate (3.00, 3.50, 4.00, 4.50 mL/min), focus time (3.00, 3.50, 4.00, 4.50 min), transition time (0.5, 1.0, 1.5, 2.0 min), pH of the carrier fluid(6.8, 7.00, 7.20, 7.40) and viscosity of the carrier fluid hydroxypropylmethylcellulose concentration: 0.00%, 0.03%, 0.06%, 1.00%). Among the 5 factors, viscosity was found to have the statistical significance on separation effectiveness which was further investigated. The resolution of high density lipoprotein and low density lipoprotein was increased by the increasing viscosity which also caused more obvious negative spikes.

CONCLUSION

The separating capacities of self-constructed asymmetrical flow field-flow fractionation system on lipoproteins were verified to be effective and an optimized experimental condition was found to achieve the base-line separation of high density lipoprotein and low density lipoprotein. Viscosity of the carrier fluid was proved to have the statistical significance on lipoprotein separation.

A novel mutation of dipeptidyl aminopeptidase-like protein-6 in a family with suspicious idiopathic ventricular fibrillation

BACKGROUND

Sudden cardiac death (SCD) occurs in a broad spectrum of cardiac pathologies and is an important cause of mortality in the general population. Idiopathic ventricular fibrillation (IVF) is a rare but important factor resulting in SCD. It is diagnosed in a resuscitated cardiac arrest victim underlying unknown cause, with documented ventricular fibrillation. Previous studies have demonstrated that mutations in dipeptidyl aminopeptidase-like protein-6 (DPP6) and cardiac sodium channel Nav1.5 (SCN5A) are the most important genetic factors involve in IVF.

AIM

By using whole sequencing to identify the genetic lesion of a family with suspicious idiopathic ventricular fibrillation.

DESIGN

Prospective genetic study.

METHODS

In this study, we employed whole-exome sequencing in combination with arrhythmia-related gene filtering to identify the genetic lesion for a family suffering from suspicious IVF, syncope and SCD. We then generated the plasmids of DPP6-pcDNA3.1+ (WT and c.1578G>C/p.Q526H). Kv4.3-pcDNA3.1+ was co-transfected together with/without DPP6-pcDNA3.1+ (WT and/or c.1578G>C/p.Q526H) into HEK293 cells to perform the patch clamp experiments.

RESULTS

A novel missense mutation (c.1578G>C/p.Q526H) of DPP6 was identified and co-segregated with affected patients in this family. Patch clamp experiments suggested that this novel mutation might result in a gain of function and disturb the efflux of potassium ion.

CONCLUSION

Our study not only reported the second missense mutation of DPP6 in heart disease and expanded the spectrum of DPP6 mutations, but also contribute to the genetic diagnosis and counseling of families with suspicious IVF, syncope and SCD.

Dosimetry study of 18F-FMISO + PET/CT hypoxia imaging guidance on intensity-modulated radiation therapy for non-small cell lung cancer

OBJECTIVES

This study was to evaluate the feasibility of simultaneous integrated boost on tumor hypoxia area by studying the dosimetric change of hypoxia imaging guidance on intensity-modulated radiation therapy for non-small cell lung cancer (NSCLC).

METHODS

Five NSCLC patients with large hypoxic volume participated in this study. FDG PET/CT images were fused with CT localization images to delineate gross tumor volume. FMISO PET/CT images were fused with CT localization images to delineate hypoxic biological target volume (BTV) (tissue maximum ratio ≥ 1.3) by threshold. BTV was irradiated with 72, 78 and 84 Gy, respectively, 30 times. The dosimetry differences were compared in target volume and organ at risk between simultaneous integrated boost plans and conventional radiotherapy plans.

RESULTS

Dosages on BTV of NSCLC hypoxic area were increased to 72, 78 and 84 Gy, respectively, by simultaneous integrated boost intensity-modulated radiation therapy. There was no obvious difference in dosage distributions on original target volume compared with those in conventional radiotherapy. Dosages on main organ at risk in chest met the dosimetric constraint, and there was no significant difference compared with those in conventional radiotherapy.

CONCLUSION

It is feasible in dosiology that the dosages in NSCLC hypoxic area were added to 72, 78 and 84 Gy by simultaneous integrated boost with the guidance of ¹⁸F-FMISO PET/CT.

Aerodynamic efficiency of a bioinspired flapping wing rotor at low Reynolds number

This study investigates the aerodynamic efficiency of a bioinspired flapping wing rotor kinematics which combines an active vertical flapping motion and a passive horizontal rotation induced by aerodynamic thrust. The aerodynamic efficiencies for producing both vertical lift and horizontal thrust of the wing are obtained using a quasi-steady aerodynamic model and two-dimensional (2D) CFD analysis at Reynolds number of 2500. The calculated efficiency data show that both efficiencies (propulsive efficiency-η_p, and efficiency for producing lift-P_f ) of the wing are optimized at Strouhal number (St) between 0.1 and 0.5 for a range of wing pitch angles (upstroke angle of attack α_u less than 45°); the St for high P_f (St = 0.1 ∼ 0.3) is generally lower than for high η_p (St = 0.2 ∼ 0.5), while the St for equilibrium rotation states lies between the two. Further systematic calculations show that the natural equilibrium of the passive rotating wing automatically converges to high-efficiency states: above 85% of maximum P_f can be obtained for a wide range of prescribed wing kinematics. This study provides insight into the aerodynamic efficiency of biological flyers in cruising flight, as well as practical applications for micro air vehicle design.

Polymerization-Induced Phase Separation Formation of Structured Hydrogel Particles via Microfluidics for Scar Therapeutics

Excessive scar formation can form disabling contractures that result in a debilitating psychological outcome. Sustainable hydrophobic corticosteroid release in vivo is essential to regulate the wound healing process. Functional hydrogel particles are widely applied for sustainable release. However, due to the limited aqueous solubility of hydrophobic compounds, most of the corticosteroid is released from the hydrogels within seconds, causing undesirable scar formation and recurrence. In this study, a novel polymerization-induced phase separation is investigated to form well-defined polyethylene glycol diacrylate (PEGDA) core/alginate shell structured hydrogel particles using microfluidics without toxic organic solvents. Based on their wettability preference, hydrophobic corticosteroid-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles are compartmentalized in the PEGDA core during polymerization to control the corticosteroid release. The distribution of the PLGA nanoparticles is precisely regulated by the phase separation boundary and characterized using a fluorescent dye. The thickness of the shell and partition coefficients are determined using the UV intensity and irradiation period. Upon encapsulation of the PLGA nanoparticles within the poly(PEGDA) core, a long-term corticosteroid treatment is developed and effective scar therapeutic outcomes are evaluated using both in vitro and in vivo models.

Lower 25-Hydroxyvitamin D Is Associated with Higher Relapse Risk in Patients with Relapsing-Remitting Multiple Sclerosis

OBJECTIVES

To investigate the association between serum circulating 25-hydroxyvitamin D [25(OH) D] concentrations and exacerbation risk in Chinese patients with relapsing-remitting multiple sclerosis (RR-MS).

METHODS

From January 2014 to December 2014, consecutive RR-MS patients admitted to the Department of Neurology of our hospital were identified. Blood samples for 25(OH) D measurements were taken at admission. All included patients visited the outpatient clinic of our hospital 1 year after admission. The influence of serum 25[OH] D levels on exacerbation was performed by binary logistic regression analysis.

RESULTS

In this study, 109 patients finished the follow-up. Median follow-up time was 1 year (range 1.0-1.1). Twenty-one out of the 109 was at risk period for infection. A total of 32 patients experienced a total of 76 exacerbations during the study. In the follow-up, a total of 32 patients experienced exacerbations. Thus, the exacerbation rate was 29.4% (95%CI: 20.8%-37.9%). Exacerbation rates were found to decrease with increasing levels of serum 25-OH-D concentrations. For the quartiles category, the risk of an exacerbation was significantly increased in the group with first quartile compared to the group with fourth. Rate ratios for the first, second and third group were 4.2, 3.3 and 2.0, respectively (p for trend =0.011) when compared with the fourth group. Simultaneous evaluation of quartile categories of levels of serum 25(OH) D and infections showed that both factors were related to the exacerbation rate.

CONCLUSION

The data demonstrates that lower vitamin D status is a sign of more active disease in patients with RR-MS and suggests a beneficial effect of vitamin D on disease course in MS.

[Clinical analysis of intestinal lymphangiectasia in 47 children]

Objective: To analyze the clinical manifestations, diagnosis, treatment and prognosis of intestinal lymphangiectasia (IL) in children in order to improve the skills of diagnosis and treatment of IL. Method: Clinical manifestations, laboratory findings, gastroscopic findings, histopathological examinations and lymphatic radionuclide imaging assessments were analyzed retrospectively among 47 IL patients who were hospitalized in the Gastroenterology Department of Beijing Children's Hospital Affiliated to Capital Medical University from June 2007 to December 2015. All patients were followed up by telephone. According to the various causes, the patients were divided into the primary intestinal lymphangiectasia (PIL) group and secondary IL group, and their clinical manifestations were compared by t test, Rank sum test or Chi-square test. Result: In 47 IL patients, there were 38 children (81%) younger than 3 years old. There were 43 PIL patients (91%) and 4 secondary IL patients (9%). Between PIL and secondary IL, there were statistical differences in serum albumin (t=-3.950, P<0.005) , globulin(t=-2.850, P=0.007), age of onset(U=27.000, P=0.024), age at diagnosis(U=29.000, P=0.030) and course of disease(U=26.500, P=0.023), whereas there were no statistical differences in lymphocyte count, IgG, lymphatic radionuclide imaging, histopathology and gender(all P>0.05). Edema (44 cases, 94%), diarrhea (42 cases, 89%), accompanied with infection (35 cases, 74%) and ascites (30 cases, 64%) were the main clinical manifestations. In 47 IL patients, 45 patients were done gastroscopy and histopathological examinations, and there were 31 patients' histopathological examinations(69%) were positive. Forty patients were done lymphatic radionuclide imaging, and there was evidence of protein losing from gut via lymphatic radionuclide imaging in 39 patients(98%). Among 47 patients, 35 patients (74%) were followed up, 32 patients had good prognosis, 2 patient failed to show evidence of improvement, 1 patient died and no patient experienced a relapse till the end of the follow-up. In 35 patients, 28 patients were treated with medium chain triglycerides (MCT) dietary therapy, 26 patients showed improvement in symptoms, and 2 patients had no improvement. Among 35 patients with follow-up, there were 6 patients received surgical treatment, and their symptoms were improved. Conclusion: PIL are the majority of IL in children younger than 3 years old. The main clinical manifestations are edema, diarrhea, accompanied with infection and ascites. For the patients without the evidence of lymphangiectasia from duodenum histopathological examination, further consideration of lymphatic radionuclide imaging, clinical manifestations, and laboratory studies are needed to make a final diagnosis. MCT dietary therapy is the cornerstone of IL medical management.

[Colonization rate of Clostridium Difficile in healthy children]

Objective: To learn the colonization of Clostridium difficile in local healthy children and to investigate the colonization rate and toxin types of Clostridium difficile at different ages. Method: From September 2014 to January 2015 in a case observational study, healthy children's fecal specimens from the health care department of Beijing Children's Hospital were collected. The children were divided into four groups according to age: <1 year old(n=53), 1-<3 years old(n=50), 3-<6 years old(n=50) and 6-<14 years old(n=50) respectively. Polymerase chain reaction (PCR) was used to detect Clostridium difficile toxin genes including tcdA, tcdB, binary toxin CDT (cdtA and cdtB), and toxin regulatory genes including tcdC, tcdD and tcdE. And then the positive samples were sequenced. Measurement data were compared by using t test and rank sum test, while, enumeration data were compared using chi-square test. Result: Fifteen (7.4%) specimens were positive for Clostridium difficile toxin genes in 203 stool specimens. Of the 15 positive specimens, eight(53.3%) were tcdA(+) tcdB(-)(A(+) B(-)), four were A(+) B(+) , 3(20.0%) were A(-)B(+) , the binary toxin-positive specimens were not detected. TcdC, tcdD, tcdE positive specimens were 8, 6 and 11, respectively. Gene mutations were not found in positive samples by DNA sequencing. In the 15 positive samples, four (7.5%) specimens were in <1 year old group; four (8.0%) specimens were in 1-<3 years old group; one(2.0%) specimen was in 3-<6 years old group; and 6(12.0%) specimens were in 6-<14 years old group. The colonization rate had no significance in different age groups. Conclusion: The colonization rate of Clostridium difficile in healthy children was 7.4%. And toxigenic Clostridium difficile can be detected in all age groups.

Role of miR-29 as marker of risk of acute rejection after heart transplant

BACKGROUND

Circulating miRNAs are potential biomarkers of the pathogenesis of certain diseases and in monitoring therapeutic responses. We hypothesized that serum miR-29 can determine risk of acute cardiac allograft rejection.

METHODS

Peripheral vein blood was collected from 50 healthy volunteers and 506 patients during post-transplant surveillance. Serum cardiac troponin I (cTnI) and miR-29 was detected by ELISA and qRT-PCR assay respectively. Rejection risk was defined as International Society of Heart and Lung Transplant score from leukocyte infiltration of an endomyocardial biopsy. No evidence of rejection was defined as grade R0, mild as R1, moderate as 2R and severe as 3R. Specificity and sensitivity of miR-29 to discriminate rejection was determined by the area under the curve (AUC) of receiver operating characteristic curve analysis. Correlations between miR29 and rejection grade were compared.

RESULTS

Serum miR-29 was 100.8 ± 42.4 copies/μl in R0 groups (P = 0.164 versus controls), 537.5 ± 84.3 copies/μl in R1 groups (P = 0.024) and 1478.4 ± 198.7 copies/μl in the joint R2/R3 groups (P = 0.001). MiR-29 was 1963.5 ± 214.7 six months after transplantation, 1242.5 ± 103.8 after a year, 825.6 ± 58.2 after 2 years, 413.8 ± 61.9 after 3 years and 270.6 ± 34.6 ng/mL after 4 years (P < 0.001). The level of miR-29 correlated positively with cTnI, NT-proBNP, white blood cell counts, and negatively with lymphocyte counts (all P < 0.001). The AUC values (95% CI) for discriminating R0 and R1 was 0.81 (0.75-0.89), and was 0.79 (0.72-0.86) for R0 and R2/R3 (both P < 0.01).

CONCLUSION

miR-29 is a promising predictor of the risk of heart transplant rejection.