Short-term neonatal and long-term infant outcome of late-preterm twins: nationwide population-based study.

OBJECTIVES: To evaluate the short- and long-term outcome of late-preterm compared with term birth in twin pregnancy. METHODS: This retrospective observational cohort study included all women who had a twin delivery between 1 January 2007 and 31 December 2010 recorded in the claims database of the Korea National Health Insurance, with at least one follow-up recorded in the database of the National Health Screening Program for Infants and Children. Outcomes were analyzed at the pregnancy level, with adverse outcome being defined as an adverse outcome in one or both twins, identified by a diagnosis according to the International Classification of Diseases 10th Revision. The primary short-term outcome was composite morbidity, which included any of the following: transient tachypnea, respiratory distress syndrome, necrotizing enterocolitis, intraventricular hemorrhage and bronchopulmonary dysplasia. Long-term adverse outcome included any neurological or neurodevelopmental outcome, defined by prespecified neurological and developmental diagnoses; these were assessed by following up all neonates until the end of 2018, by which time they were 8-11 years of age. Outcomes were compared between twins delivered late preterm (34 + 0 to 36 + 6 weeks) and those delivered at term (≥ 37 weeks). RESULTS: Among 17 189 women who delivered twins at ≥ 34 weeks of gestation during the study period, 5032 (29.27%) women delivered in the late-preterm period. On multivariate analysis, compared with the twins delivered at term, the late-preterm twins had an increased risk for the primary short-term outcome of composite morbidity (adjusted odds ratio (aOR), 2.09; 95% CI, 1.90-2.30), including transient tachypnea (aOR, 1.85; 95% CI, 1.64-2.09), respiratory distress syndrome (aOR, 2.31; 95% CI, 2.04-2.62), necrotizing enterocolitis (aOR, 2.10; 95% CI, 1.20-3.69) and intraventricular hemorrhage (aOR, 2.13; 95% CI, 1.46-3.11). For the long-term outcome, the late-preterm twins also had an increased risk for any neurological or neurodevelopmental outcome (adjusted hazard ratio, 1.14; 95% CI, 1.07-1.21). CONCLUSIONS: Twins delivered in the late-preterm period have an increased risk for short- and long-term morbidity compared with twins delivered at term. These results should be considered when determining the timing of delivery in uncomplicated twin pregnancy. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Postpartum haemorrhage requiring transfusion and risk of cardiovascular disease later in life: a retrospective cohort study.

OBJECTIVE: To determine whether postpartum haemorrhage (PPH) is associated with cardiovascular disease (CVD), including cerebrovascular and ischaemic heart disease beyond the peripartum period. DESIGN: Population-based cohort study. SETTING: Merged databases of the Korea National Health Insurance (KNHI) claims, National Health Screening Examination and National Health Screening Program for Infants and Children. POPULATION: Women who gave birth in 2007 in the Republic of Korea and who were tracked through to 2015 for the occurrence of CVD. METHODS: Patients were identified and the occurrences of PPH and transfusion were determined using the KNHI claims database. The occurrence of CVD was tracked through 2015 using codes from the International Classification of Diseases, tenth revision (ICD-10). MAIN OUTCOME MEASURES: The risk of CVD after PPH. RESULTS: Among 150 381 women who gave birth during the study period, 9107 were diagnosed with PPH and 899 were treated with transfusion. The risk of CVD in women with PPH was no different than in women without PPH, after adjustment (HR 1.03, 95% CI 0.93-1.13). The risk of CVD in women with PPH requiring transfusion was significantly increased compared with women without PPH, after adjustment (HR 1.60, 95% CI 1.25-2.06). The risk of CVD in women with PPH without transfusion was not significantly different compared with women without PPH (HR 0.96, 95% CI 0.86-1.07). CONCLUSIONS: Postpartum haemorrhage (PPH) requiring transfusion is associated with an increased risk of CVD. Guidelines for management should be established, and further studies on the mechanisms involved should be conducted. TWEETABLE ABSTRACT: PPH requiring transfusion is associated with an increased risk of CVD.

Laparoscopic sentinel node navigation surgery versus laparoscopic gastrectomy with lymph node dissection for early gastric cancer: short-term outcomes of a multicentre randomized controlled trial (SENORITA).

BACKGROUND: Sentinel node navigation surgery reduces the extent of gastric and lymph node dissection, and may improve quality of life. The benefit and harm of laparoscopic sentinel node navigation surgery (LSNNS) for early gastric cancer is unknown. The SENORITA (SEntinel Node ORIented Tailored Approach) trial investigated the pathological and surgical outcomes of LSNNS compared with laparoscopic standard gastrectomy (LSG) with lymph node dissection. METHODS: The SENORITA trial was an investigator-initiated, open-label, parallel-assigned, non-inferiority, multicentre RCT conducted in Korea. The primary endpoint was 3-year disease-free survival. The secondary endpoints, morbidity and mortality within 30 days of surgery, are reported in the present study. RESULTS: A total of 580 patients were randomized to LSG (292) or LSNNS (288). Surgery was undertaken in 527 patients (LSG 269, LSNNS 258). LSNNS could be performed according to the protocol in 245 of 258 patients, and a sentinel node basin was detected in 237 (96·7 per cent) Stomach-preserving surgery was carried out in 210 of 258 patients (81·4 per cent). Postoperative complications occurred in 51 patients in the LSG group (19·0 per cent) and 40 (15·5 per cent) in the LSNNS group (P = 0·294). Complications with a Clavien-Dindo grade of III or higher occurred in 16 (5·9 per cent) and 13 (5·0 per cent) patients in the LSG and LSNNS groups respectively (P = 0·647). CONCLUSION: The rate and severity of complications following LSNNS for early gastric cancer are comparable to those after LSG with lymph node dissection. Registration number: NCT01804998 ( http://www.clinicaltrials.gov).

ANTECEDENTES: La cirugía de navegación del ganglio centinela (sentinel node navigation surgery, SNNS) reduce la extensión de la resección gástrica y ganglionar, y puede mejorar la calidad de vida. Se desconoce el beneficio y el daño de la cirugía de navegación del ganglio centinela por vía laparoscópica (laparoscopic sentinel node navigation surgery, LSNNS) para el cáncer gástrico precoz. El ensayo clínico SENORITA investigó los resultados patológicos y quirúrgicos de LSNNS en comparación con la gastrectomía laparoscópica estándar (laparoscopic gastrectomy, LSG) con disección ganglionar (lymph node dissection, LND). MÉTODOS: El ensayo SENORITA fue un ensayo multicéntrico aleatorizado y controlado, iniciado por investigadores, abierto, con asignación a grupos paralelos y de no inferioridad llevado a cabo en Corea. El resultado primario fue la supervivencia libre de enfermedad a los 3 años. En el presente estudio, se describen los resultados secundarios correspondientes a morbilidad y mortalidad a los 30 días del postoperatorio. RESULTADOS: Un total de 580 pacientes fueron aleatorizados a LG (n = 292) o LSNNS (n = 288). La cirugía se realizó en 527 pacientes (LG 269, LSNNS 258). LSNNS pudo ser realizada de acuerdo con el protocolo en 245 de 258 pacientes y en 237 de 245 pacientes (96,7%) se detectó un ganglio centinela. La cirugía con preservación del estómago se realizó en 210 de 258 pacientes (81,4%). Las complicaciones postoperatorias se presentaron en 51 pacientes del grupo LSG (19,0%) y en 40 pacientes (15,5%) del grupo LSNNS (P = 0,294). Las complicaciones grado III o mayor de Clavien-Dindo se detectaron en 16 (5,9%) y 13 pacientes (5,0%) de los grupos LSG y LSNNS, respectivamente (P = 0,647). CONCLUSIÓN: El porcentaje y la gravedad de las complicaciones tras LSNNS para cancer gástrico precoz son comparables a la LSG con LND.

Vaginal compared with intramuscular progestogen for preventing preterm birth in high-risk pregnant women (VICTORIA study): a multicentre, open-label randomised trial and meta-analysis.

OBJECTIVE: To compare the efficacy of two types of progestogen therapy for preventing preterm birth (PTB) and to review the relevant literature. DESIGN: A multicentre, randomised, open-label, equivalence trial and a meta-analysis. SETTING: Tertiary referral hospitals in South Korea. POPULATION: Pregnant women with a history of spontaneous PTB or short cervical length (<25 mm). METHODS: Eligible women were screened and randomised at 16-22 weeks of gestation to receive either 200 mg of vaginal micronised progesterone daily (vaginal group) or an intramuscular injection of 250 mg 17α-hydroxyprogesterone caproate weekly (IM group). Stratified randomisation was carried out according to participating centres and indications for progestogen therapy. This trial was registered at ClinicalTrials.gov (NCT02304237). MAIN OUTCOME MEASURE: Preterm birth (PTB) before 37 weeks of gestation. RESULTS: A total of 266 women were randomly assigned and a total of 247 women (119 and 128 women in the vaginal and IM groups, respectively) were available for the intention-to-treat analysis. Risks of PTB before 37 weeks of gestation did not significantly differ between the two groups (22.7 versus 25.8%, P = 0.571). The difference in PTB risk between the two groups was 3.1% (95% CI -7.6 to 13.8%), which was within the equivalence margin of 15%. The meta-analysis results showed no significant differences in the risk of PTB between the vaginal and IM progestogen treatments. CONCLUSION: Compared with vaginal progesterone, treatment with intramuscular progestin might increase the risk of PTB before 37 weeks of gestation by as much as 13.8%, or reduce the risk by as much as 7.6%, in women with a history of spontaneous PTB or with short cervical length. TWEETABLE ABSTRACT: Vaginal and intramuscular progestogen showed equivalent efficacy for preventing preterm birth before 37 weeks of gestation.

DNA barcoding of pear psyllids (Hemiptera: Psylloidea: Psyllidae), a tale of continued misidentifications.

Pear psyllids (Hemiptera: Psylloidea: Psyllidae: Cacopsylla spp.) belong to the most serious pests of pear (Pyrus spp.). They damage pear trees by excessive removal of phloem sap, by soiling the fruits with honeydew which, in turn, provides a substrate for sooty mould, and by transmission of Candidatus Phytoplasma spp., the causal agents of the pear decline disease. The morphological similarity, the presence of seasonal dimorphism that affects adult colour, size and wing morphology and uncritical use of species names, led to much confusion in the taxonomy of pear psyllids. As a result, pear psyllids have been frequently misidentified. Many of the entries attributed to Cacopsylla pyricola and other species in the GenBank are misidentifications which led to additional, unnecessary confusion. Here we analysed DNA barcodes of 11 pear psyllid species from eastern Asia, Europe and Iran using four mitochondrial gene fragments (COI 658 bp, COI 403 bp, COI-tRNAleu-COII 580 bp and 16S rDNA 452 bp). The efficiency of identification was notably high and considerable barcoding gaps were observed in all markers. Our results confirm the synonymies of the seasonal forms of Cacopsylla jukyungi ( = C. cinereosignata, winter form) and C. maculatili ( = C. qiuzili, summer form) previously suggested based on morphology. Some previous misidentifications (C. chinensis from China, Japan and Korea = misidentification of C. jukyungi; C. pyricola and C. pyrisuga from East Asia = misidentification of C. jukyungi and C. burckhardti, respectively; C. pyricola from Iran = misidentification of C. bidens, C. pyri and Cacopsylla sp.) are also corrected. There is no evidence for the presence of European pear psyllid species in East Asia.

2018 European Conference on Donor Health and Management.

The third European Conference on Donor Health and Management (ECDHM) was held in Copenhagen from 5th to 7th September 2018 and was co-organised by the ECDHM committees and European Blood Alliance. This is an international conference with a focus on 'donor health', including donors of blood, organs and other substances of human origin, and remains the only conference focusing exclusively on donor medicine. This overview presents a selection of research topics in relation to iron, the keynote speeches and plenary talks. The keynote speeches cover the epidemiology of donors and recipients, whole-blood donor recruitment and retention and the safety of donors and recipients of plasma and plasma products. Talks from the plenary speakers reviewed modern multi-omic approaches to study red cell quality and the central, perennial question of what motivates a donor to give blood and how can this be encouraged.

Women with threatened preterm labour followed by term delivery have an increased risk of spontaneous preterm birth in subsequent pregnancies: a population-based cohort study.

OBJECTIVES: To evaluate the association of a history of threatened preterm labour (TPL) followed by term delivery with the risk of spontaneous preterm delivery (PTD) in subsequent pregnancy. DESIGN: Population-based cohort study. SETTING: Data of the National Health Insurance Claims Database and a national health-screening programme for infants and children in South Korea. POPULATION: Women who had their first singleton delivery in 2010 and a subsequent second singleton delivery between 2011 and 2015. METHODS: Multivariable analysis adjusting for maternal age and interval between first and second deliveries was used to assess the risk of PTD based on PTD, TPL followed by term delivery, and term delivery in the first pregnancy. MAIN OUTCOME MEASURES: The risk of PTD during the second pregnancy. RESULTS: This study included 115 629 women with two consecutive deliveries during the study period. Spontaneous PTD rates in the second pregnancy were 7.71, 2.22 and 1.02% in women with PTD, TPL followed by term delivery, and term delivery in the first pregnancy, respectively. Threatened preterm labour followed by term delivery in the first pregnancy was associated with increased risk of PTD in the subsequent pregnancy after adjustment for potential confounding factors (adjusted odds ratio 2.21; 95% CI 1.76-2.78). CONCLUSION: Although women with a history of TPL followed by term delivery had a lower risk of PTD during a subsequent pregnancy compared with those with history of previous PTD, they still had a significantly increased risk of PTD compared with those who delivered at term without TPL. TWEETABLE ABSTRACT: The history of threatened preterm labour followed by term delivery is related to increased risk of subsequent spontaneous preterm delivery.

Cost-effectiveness of alternative changes to a national blood collection service.

OBJECTIVES: To evaluate the cost-effectiveness of changing opening times, introducing a donor health report and reducing the minimum inter-donation interval for donors attending static centres. BACKGROUND: Evidence is required about the effect of changes to the blood collection service on costs and the frequency of donation. METHODS/MATERIALS: This study estimated the effect of changes to the blood collection service in England on the annual number of whole-blood donations by current donors. We used donors' responses to a stated preference survey, donor registry data on donation frequency and deferral rates from the INTERVAL trial. Costs measured were those anticipated to differ between strategies. We reported the cost per additional unit of blood collected for each strategy versus current practice. Strategies with a cost per additional unit of whole blood less than £30 (an estimate of the current cost of collection) were judged likely to be cost-effective. RESULTS: In static donor centres, extending opening times to evenings and weekends provided an additional unit of whole blood at a cost of £23 and £29, respectively. Introducing a health report cost £130 per additional unit of blood collected. Although the strategy of reducing the minimum inter-donation interval had the lowest cost per additional unit of blood collected (£10), this increased the rate of deferrals due to low haemoglobin (Hb). CONCLUSION: The introduction of a donor health report is unlikely to provide a sufficient increase in donation frequency to justify the additional costs. A more cost-effective change is to extend opening hours for blood collection at static centres.

The robustness of T2 value as a trabecular structural index at multiple spatial resolutions of 7 Tesla MRI.

PURPOSE: To evaluate the robustness of MR transverse relaxation times of trabecular bone from spin-echo and gradient-echo acquisitions at multiple spatial resolutions of 7 T. METHODS: The effects of MRI resolutions to T2 and T2* of trabecular bone were numerically evaluated by Monte Carlo simulations. T2 , T2*, and trabecular structural indices from multislice multi-echo and UTE acquisitions were measured in defatted human distal femoral condyles on a 7 T scanner. Reference structural indices were extracted from high-resolution microcomputed tomography images. For bovine knee trabecular samples with intact bone marrow, T2 and T2* were measured by degrading spatial resolutions on a 7 T system. RESULTS: In the defatted trabecular experiment, both T2 and T2* values showed strong ( |r| > 0.80) correlations with trabecular spacing and number, at a high spatial resolution of 125 µm3 . The correlations for MR image-segmentation-derived structural indices were significantly degraded ( |r| < 0.50) at spatial resolutions of 250 and 500 µm3 . The correlations for T2* rapidly dropped ( |r| < 0.50) at a spatial resolution of 500 µm3 , whereas those for T2 remained consistently high ( |r| > 0.85). In the bovine trabecular experiments with intact marrow, low-resolution (approximately 1 mm3 , 2 minutes) T2 values did not shorten ( |r| > 0.95 with respect to approximately 0.4 mm3 , 11 minutes) and maintained consistent correlations ( |r| > 0.70) with respect to trabecular spacing (turbo spin echo, 22.5 minutes). CONCLUSION: T2 measurements of trabeculae at 7 T are robust with degrading spatial resolution and may be preferable in assessing trabecular spacing index with reduced scan time, when high-resolution 3D micro-MRI is difficult to obtain.

Template-free synthesis of monolithic carbon xerogels with hierarchical porosity from resorcinol and formaldehyde via hydrothermal reaction.

Monolithic carbon xerogels with hierarchical porosity were prepared from resorcinol (R) and formaldehyde (F) via a base-catalysed hydrothermal polycondensation reaction, without a template and supercritical drying. First, an aqueous solution of resorcinol, formaldehyde and sodium carbonate was prepared by varying R/W (25-45) and R/C (1-10k) ratios to produce monolithic RF gels. The reaction was carried out in a pressurized Teflon mould at 100 °C for 6 h to give a co-continuous pore structure via spinodal decomposition and a tenacious gel to avoid supercritical drying. Next, the RF gels were dried for 42 h at 60 °C and another 6 h at 100 °C to produce RF xerogels without cracks, followed by pyrolysis in a tube furnace at 900 °C for 2 h under N2 flow, and then activation at 1000 °C for 2, 4 or 6 h under CO2 flow. Finally, the carbon xerogels were characterized by SEM and N2 adsorption-desorption measurements. Monolithic RF gels were obtained from all combinations of R/W and R/C, but the gels from R/W = 45 exhibited a co-continuous large-pore structure, providing a specific surface area (SSA) of ∼650 m2 g-1, which increased to 3311 m2 g-1 (for R/C = 10k) at 6 h of CO2 activation without exhibiting cracks. N2 isotherms demonstrated that micro- and meso-pores were introduced via activation, forming hierarchical porosity in combination with large pores from spinodal decomposition without using a template.

Effect of relative humidity on preeclampsia.

PURPOSE OF INVESTIGATION: The authors aimed to determine the relationship between meteorological variables and hypertension in pregnancy by using data from a national weather database. MATERIALS AND METHODS: For this population-based observational study, the database of the Korea National Health Insurance (KNHI) Claims of the Health Insurance Review and Assessment Service (HIRA) and Korea Meteorological Administration was used. The 48,275 women with preeclampsia among 2,495,383 women who gave birth were included. Monthly meteorological factors and preeclampsia prevalence for five years were statistically analyzed. RESULTS: Among temperature, relative humidity, sunlight duration, and rainfall, only relative humidity had a significant inverse correlation with the preeclampsia prevalence (p < 0.001). The other meteorological factors were not associated with preeclampsia. CONCLUSION: Relative humidity may be a significant factor for of the development of preeclampsia. Further monitoring of weather parameters during the entire pregnancy period may be the best method for verifying the present results in the development of preeclampsia.

Correlation between lymph node count and survival and a reappraisal of lymph node ratio as a predictor of survival in gastric cancer: A multi-institutional cohort study.

PURPOSE: The purpose of this study is to evaluate the correlation between lymph node count (LNC) and survival and to evaluate whether lymph node ratio (LNR) which is related to LNC is a better predictor of survival for gastric cancer than the N category of UICC/AJCC through a multi-institutional cohort study. METHODS: The study cohort included 3284 patients from eight institutions. Lower and upper quartiles of LNC were used for comparisons. The cut-off values (0, 0.06, 0.27, and 0.49) for the LNR categories were based on Classification and Regression Trees techniques. Akaike information criteria (AIC) for Cox regression models was used to evaluate goodness of fit between competing predictor variables (LNR vs. N category). RESULTS: The 5-year disease-specific survival (DSS) rates of lower and upper quartiles of LNC were 82.2% and 84.8%. In the subgroup analysis of pN category, the upper quartile of LNC showed better survival than the lower quartile in pN2, pN3a, and pN3b subgroups. Regarding LNR, 5-year DSS of LNR 0, 0-0.06, 0.06-0.27, 0.27-0.49, and >0.49 was 95.3%, 88.7%, 70.6%, 42.7%, and 17.2% respectively. Multivariate analysis showed that pT, pN, LNR, residual tumor status, distant metastasis, and tumor differentiation significantly affected survival. The analysis also confirmed superiority of LNR compared with N category in the AIC analysis. CONCLUSION: Higher LNC correlated with better survival in patients with pN2, pN3a, and pN3b gastric cancer. Our data indicate that LNR is a better predictor of survival than N category of UICC/AJCC.

POST-HARVEST EMBRYO DEVELOPMENT IN GINSENG SEEDS INCREASES DESICCATION SENSITIVITY AND NARROWS THE HYDRATION WINDOW FOR CRYOPRESERVATION.

BACKGROUND: Despite its self-pollinating characteristics, Korean ginseng germplasm is mainly maintained in clonal gene banks as there is no defined approach to the long-term conservation of its seed, including the most appropriate stage of embryo development for storage. OBJECTIVE: The aim of this study was to reveal the effect of embryo development on desiccation tolerance and cryopreservation success in ginseng seeds. MATERIALS AND METHODS: Seeds of Korean ginseng (Panax ginseng C.A. Meyer) at three post-harvest stages (immediately after harvesting and following treatments to enable internal growth of the embryo) were desiccated and cryopreserved. RESULTS: The hydration window for the >80% dehiscence and germination of cryopreserved ginseng seeds varied with embryo developmental stage: 3-9% moisture content (MC) for both unpulped and undehisced seeds when the embryo was 0.1 the length of the endosperm, 7-10% MC for dehisced seeds (0.5 embryo:endosperm) and 9-11% MC for seeds with fully developed embryos (0.9 embryo:endosperm). Whilst dried (4-8% moisture content) and undehisced seeds within fruits (unpulped seeds) lost more than half their viability during 1 year's storage at room temperature, cryopreservation enabled germination levels of c. 90%. Overall, 432 accessions of Korean ginseng landraces have been cryopreserved using undehisced seeds with or without fruits. CONCLUSION: Post-harvest treatment of Korean ginseng seeds to enable embryo development decreases tolerance of very low MCs, and thus narrows the hydration window for cryopreservation. Fresh-harvested and unpulped seeds that have been dried to c. 5% MC are recommended for long-term cryogenic storage.

Robust MR assessment of cerebral blood volume and mean vessel size using SPION-enhanced ultrashort echo acquisition.

Intravascular superparamagnetic iron oxide nanoparticles (SPION)-enhanced MR transverse relaxation rates (∆R2(⁎) and ∆R2) are widely used to investigate in vivo vascular parameters, such as the cerebral blood volume (CBV), microvascular volume (MVV), and mean vessel size index (mVSI, ∆R2(⁎)/∆R2). Although highly efficient, regional comparison of vascular parameters acquired using gradient-echo based ∆R2(⁎) is hampered by its high sensitivity to magnetic field perturbations arising from air-tissue interfaces and large vessels. To minimize such demerits, we took advantage of the dual contrast property of SPION and both theoretically and experimentally verified the direct benefit of replacing gradient-echo based ∆R2(⁎) measurement with ultra-short echo time (UTE)-based ∆R1 contrast to generate the robust CBV and mVSI maps. The UTE acquisition minimized the local measurement errors from susceptibility perturbations and enabled dose-independent CBV measurement using the vessel/tissue ∆R1 ratio, while independent spin-echo acquisition enabled simultaneous ∆R2 measurement and mVSI calculation of the cortex, cerebellum, and olfactory bulb, which are animal brain regions typified by significant susceptibility-associated measurement errors.

Surface Collective Modes in the Topological Insulators Bi_{2}Se_{3} and Bi_{0.5}Sb_{1.5}Te_{3-x}Se_{x}.

We used low-energy, momentum-resolved inelastic electron scattering to study surface collective modes of the three-dimensional topological insulators Bi_{2}Se_{3} and Bi_{0.5}Sb_{1.5}Te_{3-x}Se_{x}. Our goal was to identify the "spin plasmon" predicted by Raghu and co-workers [Phys. Rev. Lett. 104, 116401 (2010)]. Instead, we found that the primary collective mode is a surface plasmon arising from the bulk, free carriers in these materials. This excitation dominates the spectral weight in the bosonic function of the surface χ^{"}(q,ω) at THz energy scales, and is the most likely origin of a quasiparticle dispersion kink observed in previous photoemission experiments. Our study suggests that the spin plasmon may mix with this other surface mode, calling for a more nuanced understanding of optical experiments in which the spin plasmon is reported to play a role.

Simulational validation of color magnetic particle imaging (cMPI).

Exploiting the field response of magnetic tracers, magnetic particle imaging (MPI) allows direct, local quantification of the tracer concentration in bulk structures. Here, we investigated the use of characteristic field response functions to spatially resolve the absolute concentration of multiple nanoparticle species by simulation. In particular, using various drive and selection field strengths, we devised color MPI (i.e. cMPI) to quantify and disentangle MPI signals from the mixed Langevin particles of variable concentration and magnetic susceptibility. Specifically, the drive field strength was optimized to distinguish individual field responses from differently sized iron-oxide nanoparticles without compromising the image quality. The proposed cMPI technique is implementable on an existing MPI setup and can be used to quantify biophysical parameters including size-dependent bio-distribution and altered magnetic property of particles. The current study result, simultaneous visualization of the multiple magnetic tracers, theoretically validates the potential feasibility of cMPI as a versatile biosensor and contrast imaging method.

Ultrafast 3D spin-echo acquisition improves Gadolinium-enhanced MRI signal contrast enhancement.

Long scan times of 3D volumetric MR acquisitions usually necessitate ultrafast in vivo gradient-echo acquisitions, which are intrinsically susceptible to magnetic field inhomogeneities. This is especially problematic for contrast-enhanced (CE)-MRI applications, where non-negligible T2* effect of contrast agent deteriorates the positive signal contrast and limits the available range of MR acquisition parameters and injection doses. To overcome these shortcomings without degrading temporal resolution, ultrafast spin-echo acquisitions were implemented. Specifically, a multiplicative acceleration factor from multiple spin echoes (×32) and compressed sensing (CS) sampling (×8) allowed highly-accelerated 3D Multiple-Modulation-Multiple-Echo (MMME) acquisition. At the same time, the CE-MRI of kidney with Gd-DOTA showed significantly improved signal enhancement for CS-MMME acquisitions (×7) over that of corresponding FLASH acquisitions (×2). Increased positive contrast enhancement and highly accelerated acquisition of extended volume with reduced RF irradiations will be beneficial for oncological and nephrological applications, in which the accurate in vivo 3D quantification of contrast agent concentration is necessary with high temporal resolution.

Effects of sFlt-1 and alpha 2-macroglobulin on vascular endothelial growth factor-induced endothelin-1 upregulation in human microvascular endothelial cells.

INTRODUCTION: Soluble fms-like tyrosine kinase-1 (sFlt-1) is a vascular endothelial growth factor (VEGF) binding protein and potent antagonist of VEGF. Alpha 2 macroglobulin (α2M) is another major binding protein for circulating VEGF, which is present in human plasma at higher concentration (2-4 mg/mL) than sFlt-1. This study investigated the effects of sFlt-1 and α2M on VEGF-induced endothelin-1 (ET-1) upregulation in human microvascular endothelial cell-1 (HMEC-1). METHODS: HMEC-1 was cultured and incubated with varying concentrations of sFlt-1 and α2M in combination with VEGF. ET-1 mRNA expression in the cells was measured by real time RT-PCR and ET-1 protein by western blot analysis. RESULTS: ET-1 expression in HMEC-1 incubated with VEGF significantly increased in time- and dose-dependent manners. Next, HMEC-1 was treated with the sFlt-1 (10-1000 ng/mL) or α2M (10-10000 ng/mL) in the presence of VEGF (10 ng/mL). We found that sFlt-1 induced a significant decrease of ET-1 expression upregulated by VEGF, while α2M did not affect the VEGF-induced ET-1 expression. CONCLUSIONS: sFLT-1 suppressed the VEGF-induced the ET-1 expression of HMEC-1. However, α2M did not show a significant effect on the ET-1 expression that was induced by VEGF. The results suggest that a certain proportion of the bound form α2M-VEGF have a biological action involved in the pathophysiology of preeclampsia.