Seedlings of Poncirus trifoliata exhibit tissue-specific detoxification in response to NH4 + toxicity

Ammonium nitrogen (NH4 +-N) is essential for fruit tree growth, but the impact of excess NH4 +-N from fertilizer on evergreen citrus trees is unclear. In a climate chamber, 8-month-old citrus plants were exposed to five different hydroponic NH4 +-N concentrations (0, 5, 10, 15 and 20 mm) for 1 month to study effects of NH4 +-N on growth characteristics, N uptake, metabolism, antioxidant enzymes and osmotic regulatory substances. Application of 10 mm NH4 +-N adversely affected root plasma membrane integrity, root physiological functions, and plant biomass. MDA, CAT, POD, APX and SOD content were significantly correlated with leaf N metabolic enzyme activity (GOGAT, GDH, GS and NR). GDH was the primary enzyme involved in NH4 +-N assimilation in leaves, while the primary pathway involved in roots was GS-GOGAT. Under comparatively high NH4 + addition, roots were the main organs involved in NH4 + utilization in citrus seedlings. Our results demonstrated that variations in NH4 + concentration and enzyme activity in various organs are associated with more effective N metabolism in roots than in leaves to prevent NH4 + toxicity in evergreen woody citrus plants. These results provide insight into the N forms used by citrus plants that are important for N fertilizer management.

Blue light regulated lignin and cellulose content of soybean petioles and stems under low light intensity

To improve light harvest and plant structural support under low light intensity, it is useful to investigate the effects of different ratios of blue light on petiole and stem growth. Two true leaves of soybean seedlings were exposed to a total light intensity of 200μmolm-2 s-1 , presented as either white light or three levels of blue light (40μmolm-2 s-1 , 67μmolm-2 s-1 and 100μmolm-2 s-1 ) for 15days. Soybean petioles under the low blue light treatment upregulated expression of genes relating to lignin metabolism, enhancing lignin content compared with the white light treatment. The low blue light treatment had high petiole length, increased plant height and improved petiole strength arising from high lignin content, thus significantly increasing leaf dry weight relative to the white light treatment. Compared with white light, the treatment with the highest blue light ratio reduced plant height and enhanced plant support through increased cellulose and hemicellulose content in the stem. Under low light intensity, 20% blue light enhanced petiole length and strength to improve photosynthate biomass; whereas 50% blue light lowered plants' centre of gravity, preventing lodging and conserving carbohydrate allocation.

Fibulin-1 Regulates Initiation of Successional Dental Lamina

In humans, teeth are replaced only once, and the successional dental lamina (SDL) of the permanent tooth is maintained in a quiescent state until adolescence. Recently, we showed that biomechanical stress generated by the rapid growth of the deciduous tooth inhibits SDL development via integrin β1-RUNX2 signaling at embryonic day 60 (E60) in miniature pigs. However, the mechanism by which RUNX2 regulates SDL initiation within the SDL stem cell niche remains unclear. In the current study, we transcriptionally profiled single cells from SDL and surrounding mesenchyme at E60 and identified the landscape of cellular heterogeneity. We then identified a specific fibroblast subtype in the dental follicle mesenchyme between the deciduous tooth and the SDL of the permanent tooth (DFDP), which constitutes the inner part of the niche (deciduous tooth side). Compared with traditional dental follicle cells, the specific expression profile of DFDP was identified and found to be related to biomechanical stress. Subsequently, we found that RUNX2 could bind to the enhancer regions of Fbln1 (gene of fibulin-1), one of the marker genes for DFDP. Through gain- and loss-of-function experiments, we proved that the biomechanical stress-mediated RUNX2-fibulin-1 axis inhibits the initiation of SDL by maintaining SDL niche homeostasis.

Contouring Analysis on Synthetic Contrast-Enhanced MR from GRMM-GAN and Implications on MR-Guide Radiation Therapy

PURPOSE/OBJECTIVE(S)

MR-guided linear accelerators have been commercialized making MR-only planning and adaptation an appealing alternative circumventing MR-CT registration. However, obtaining daily contrast-enhanced MR images can be prohibitive due to the increased risk of side effects from repeated contrast injections. In this work, we evaluate the quality of contrast-enhanced multi-modal MR image synthesis network GRMM-GAN (gradient regularized multi-modal multi-discrimination sparse-attention fusion generative adversarial network) for MR-guided radiation therapy.

MATERIALS/METHODS

With IRB approval, we trained the GRMM-GAN based on 165 abdominal MR studies from 65 patients. Each study included T2, T1 pre-contrast (T1pre), and T1 contrast enhanced (T1ce) images. The two pre-contrast MR modalities, T2 and T1pre images were adopted as inputs for GRMM-GAN, and the T1ce image at the portal venous phase was used as an output. Ten MR scans containing 21 liver tumors were selected for contouring analysis. A Turing test was first given to six radiation oncologists, in which 100 real T1ce and synthetic T1ce image slices are randomly given to the radiation oncologists to determine the authenticity of the synthesis. We then invited two radiation oncologists (RadOnc 1 and RadOnc2) to manually contour the 21 liver tumors independently on the real T1ce images. RadOnc2 then performed contouring on the respective synthetic T1ce MRs. DICE coefficient (defined as the intersection over the average of two volumes) and Hausdorff distance (HD, measuring how far two volumes are from each other) were used as analysis metrics. The DICE coefficients were calculated from the two radiation oncologists' contours on the real T1ce MR for each tumor. The DICE coefficients were also calculated from RadOnc 2's contours on real and synthetic MRs. Besides, tumor center shifts were extracted. The tumor center of mass coordinates was extracted from real and synthetic volumes. The difference in the coordinates indicated the shifts in the superior-inferior (SI), right-left (RL), and anterior-posterior (AP) directions between real and synthetic tumor volumes.

RESULTS

An average of 52.3% test score was achieved from the six radiation oncologists, which is close to random guessing. RadOnc 1 and RadOnc 2, who had participated in the contouring analysis, achieved an average DICE of 0.91±0.02 from tumor volumes drawn on the real T1ce MRs. This result sets the inter-operator uncertainty baseline in the real clinical setting. RadOnc 2 achieved an average DICE (real vs. synth) of 0.90±0.04 and HD of 4.76±1.82 mm. Only sub-millimeter (SI: 0.67 mm, RL: 0.41 mm, AP: 0.39 mm) tumor center shifts were observed in all three directions.

CONCLUSION

The GRMM-GAN method has the potential for MR-guided liver radiation when contrast agents cannot be administered daily and provide synthetic contrast-enhanced MR for better tumor targeting. The network can produce synthetic MR images with satisfactory contour agreement and geometric integrity.

Beneficial effects of red and blue light on potato leaf antioxidant capacity and tuber bulking

Artificial light application is an effective method for promoting potato production in indoor facilities. In this study, we assessed the effects of different combinations of red (R) and blue (B) light application on potato leaf and tuber growth. Potato plantlets were transplanted under W (white light, control), RB5-5 (50% R + 50% B), RB3-7 (30% R + 70% B to 70% R + 30% B) and RB1-9 (10% R + 90% B to 90% R + 10% B), and ascorbic acid (AsA) metabolism in leaves and cytokinin (CTK), auxin (indole-3-acetic acid, IAA), abscisic acid (ABA), and gibberellin (GA) levels in tubers were measured. At 50 days of treatment, potato leaves had significantly higher L-galactono-1,4-lactone dehydrogenase (GalLDH) activity and utilized AsA faster under RB1-9 treatment than under RB3-7 treatment. CTK/IAA and ABA/GA ratios in large tubers under W treatment did not differ significantly from those under RB1-9 treatment, which had higher levels than those under RB5-5 and RB3-7 treatment at 50 days. However, under RB1-9 treatment, total leaf area decreased rapidly from 60 to 75 days compared with plants under RB3-7 treatment. Tuber dry weight per plant under W and RB5-5 treatment approached a plateau at 75 days. At 80 days, RB3-7 treatment significantly improved ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase activity compared with RB1-9 treatment. RB1-9 treatment with a high ratio of blue light increased CTK/IAA and ABA/GA to improve tuber bulking at 50 days, while RB3-7 treatment with a high ratio of red light stimulated AsA metabolic pathway to delay leaf oxidation and maintain tuber biomass accumulation at 80 days. For the indoor potato cultivation, RB3-7 treatment had a higher proportion of medium-sized tubers, thus being a suitable light treatment.

A study on prenucleation and heterogeneous nucleation in liquid Pb on solid Al using molecular dynamics simulations

In this paper, we investigate prenucleation and heterogeneous nucleation in the liquid Pb/solid Al system as an example of systems with large lattice misfit using molecular dynamics simulation. Solid Pb and Al have a large positive lattice misfit (f) of 18.2% along the densely packed [110] direction. This study reveals that prenucleation occurs at 600 K (an undercooling of 15 K), and a 2-dimensional (2D) ordered structure forms at the interface with a coincidence site lattice (CSL) between the first Pb and first Al layers. The CSL accommodates the major part of the f, and only a small residual lattice misfit (f_r) of 1.9% remains. The formation of the CSL transforms the original substrate into a considerably potent nucleant, where the first Pb layer becomes the new surface layer of the substrate. At an undercooling of about 22 K, nucleation proceeds by merging 2D ordered structure through structural templating: the second Pb layer is epitaxial to the CSL Pb layer, the third Pb layer largely accommodates the f_r, and the fourth Pb layer is a nearly perfect crystalline plane. Further analysis indicates that the interface with the CSL has a lower interfacial energy than with a cube-to-cube orientation relationship. For the first time, we established that the CSL was an effective mechanism to accommodate the f for systems with a large positive misfits. Heterogeneous nucleation is governed not by a single mechanism (misfit dislocations in Turnbull's model), but instead by various mechanisms depending on f. This study sheds new light on the atomistic mechanism of heterogeneous nucleation.

Mid-infrared frequency combs and staggered spectral patterns in χ(2) microresonators

The potential of frequency comb spectroscopy has aroused great interest in generating mid-infrared frequency combs in the integrated photonic setting. However, despite remarkable progress in microresonators and quantum cascade lasers, the availability of suitable mid-IR comb sources remains scarce. Here, we generate mid-IR microcombs relying on cascaded three-wave-mixing for the first time. By pumping a CdSiP₂ microresonator at 1.55 µm wavelength with a low power continuous wave laser, we generate χ⁽²⁾ frequency combs at 3.1 µm wavelength, with a span of about 30 nm. We observe ordinary combs states with a line spacing of the free spectral range of the resonator, and combs where the sideband numbers around the pump and half-harmonic alternate, forming staggered patterns of spectral lines. Our scheme for mid-IR microcomb generation is compatible with integrated telecom lasers. Therefore, it has the potential to be used as a simple and fully integrated mid-IR comb source, relying on only one single material.

Plant-specific features of respiratory supercomplex I + III2 from Vigna radiata

The last steps of cellular respiration-an essential metabolic process in plants-are carried out by mitochondrial oxidative phosphorylation. This process involves a chain of multi-subunit membrane protein complexes (complexes I-V) that form higher-order assemblies called supercomplexes. Although supercomplexes are the most physiologically relevant form of the oxidative phosphorylation complexes, their functions and structures remain mostly unknown. Here we present the cryogenic electron microscopy structure of the supercomplex I + III₂ from Vigna radiata (mung bean). The structure contains the full subunit complement of complex I, including a newly assigned, plant-specific subunit. It also shows differences in the mitochondrial processing peptidase domain of complex III₂ relative to a previously determined supercomplex with complex IV. The supercomplex interface, while reminiscent of that in other organisms, is plant specific, with a major interface involving complex III₂'s mitochondrial processing peptidase domain and no participation of complex I's bridge domain. The complex I structure suggests that the bridge domain sets the angle between the enzyme's two arms, limiting large-scale conformational changes. Moreover, complex I's catalytic loops and its response in active-to-deactive assays suggest that, in V. radiata, the resting complex adopts a non-canonical state and can sample deactive- or open-like conformations even in the presence of substrate. This study widens our understanding of the possible conformations and behaviour of complex I and supercomplex I + III₂. Further studies of complex I and its supercomplexes in diverse organisms are needed to determine the universal and clade-specific mechanisms of respiration.

Overall survival in the OlympiA phase III trial of adjuvant olaparib in patients with germline pathogenic variants in BRCA1/2 and high risk, early breast cancer

BACKGROUND

The randomized, double-blind OlympiA trial compared 1 year of the oral poly(adenosine diphosphate-ribose) polymerase inhibitor, olaparib, to matching placebo as adjuvant therapy for patients with pathogenic or likely pathogenic variants in germline BRCA1 or BRCA2 (gBRCA1/2pv) and high-risk, human epidermal growth factor receptor 2-negative, early breast cancer (EBC). The first pre-specified interim analysis (IA) previously demonstrated statistically significant improvement in invasive disease-free survival (IDFS) and distant disease-free survival (DDFS). The olaparib group had fewer deaths than the placebo group, but the difference did not reach statistical significance for overall survival (OS). We now report the pre-specified second IA of OS with updates of IDFS, DDFS, and safety.

PATIENTS AND METHODS

One thousand eight hundred and thirty-six patients were randomly assigned to olaparib or placebo following (neo)adjuvant chemotherapy, surgery, and radiation therapy if indicated. Endocrine therapy was given concurrently with study medication for hormone receptor-positive cancers. Statistical significance for OS at this IA required P < 0.015.

RESULTS

With a median follow-up of 3.5 years, the second IA of OS demonstrated significant improvement in the olaparib group relative to the placebo group [hazard ratio 0.68; 98.5% confidence interval (CI) 0.47-0.97; P = 0.009]. Four-year OS was 89.8% in the olaparib group and 86.4% in the placebo group (Δ 3.4%, 95% CI -0.1% to 6.8%). Four-year IDFS for the olaparib group versus placebo group was 82.7% versus 75.4% (Δ 7.3%, 95% CI 3.0% to 11.5%) and 4-year DDFS was 86.5% versus 79.1% (Δ 7.4%, 95% CI 3.6% to 11.3%), respectively. Subset analyses for OS, IDFS, and DDFS demonstrated benefit across major subgroups. No new safety signals were identified including no new cases of acute myeloid leukemia or myelodysplastic syndrome.

CONCLUSION

With 3.5 years of median follow-up, OlympiA demonstrates statistically significant improvement in OS with adjuvant olaparib compared with placebo for gBRCA1/2pv-associated EBC and maintained improvements in the previously reported, statistically significant endpoints of IDFS and DDFS with no new safety signals.

Delayed application of N fertilizer mitigates the carbon emissions of pea/maize intercropping via altering soil microbial diversity

Strategies to reduce carbon emissions have been a hotspot in sustainable agriculture production. The delayed N fertilizer application had the potential to reduce carbon emissions in pea (Pisum sativum L.)/maize (Zea mays L.) intercropping, but its microbial mechanism remains unclear. In this study, we investigated the effects of delayed N fertilizer application on CO2 emissions and soil microbial diversity in pea/maize intercropping. The soil respiration (Rs) rates of intercropped pea and intercropped maize were decreased by 24.7% and 25.0% with delayed application of N fertilizer, respectively. The total carbon emissions (TCE) of the pea/maize intercropping system were also decreased by 21.1% compared with that of the traditional N fertilizer. Proteobacteria, Bacteroidota, and Chloroflexi were dominant bacteria in pea and maize strips. Heatmap analysis showed that the soil catalase activity at the pea flowering stage and the soil ΝΗ4+-Ν at the maize silking stage contributed more to the variations of bacterial relative abundances than other soil properties. Network analysis demonstrated that Rs was positively related to the relative abundance of Proteobacteria and Bacteroidota, while negatively related to the relative abundance of Chloroflexi in the pea/maize intercropping system. Overall, our results suggested that the delayed application of N fertilizer combined with the pea/maize intercropping system altered soil bacterial community diversity, thereby providing novel insights into connections between soil microorganisms and agricultural carbon emissions.

No-till and nitrogen fertilizer reduction improve nitrogen translocation and productivity of spring wheat (Triticum aestivum L.) via promotion of plant transpiration

Excessive nitrogen (N) fertilizer has threatened the survivability and sustainability of agriculture. Improving N productivity is promising to address the above issue. Therefore, the field experiment, which investigated the effect of no-till and N fertilizer reduction on water use and N productivity of spring wheat (Triticum aestivum L.), was conducted at Wuwei experimental station in northwestern China. There were two tillage practices (conventional tillage, CT; and no-till with previous plastic film mulching, NT) and three N fertilizer rates (135 kg N ha^-1, N1; 180 kg N ha^-1, N2; and 225 kg N ha^-1, N3). The results showed that NT lowered soil evaporation (SE) by 22.4% while increasing the ratio of transpiration to evapotranspiration (T/ET) by 13.6%, compared with CT. In addition, NT improved the total N accumulation by 11.5% and enhanced N translocation (NT) quantity, rate, and contribution by a range of 6.2-23.3%. Ultimately, NT increased grain yield (GY), N partial factor productivity, and N harvest index by 13.4, 13.1, and 26.0%, respectively. Overall, N1 increased SE (13.6%) but decreased T/ET (6.1%) compared with N3. While, N2 enhanced NT quantity, rate, and contribution by a range of 6.0-15.2%. With the integration of NT, N2 achieved the same level of GY and N harvest index as N3 and promoted N partial factor productivity by 11.7%. The significant positive correlation of NT relative to T/ET and GY indicated that improving T/ET was essential for achieving higher NT. Therefore, we concluded that no-till coupled with N fertilizer rate at 180 kg N ha^-1 was a preferable management option to boost the N productivity of spring wheat in arid areas.

Energy budgeting, carbon budgeting, and carbon footprints of straw and plastic film management for environmentally clean of wheat-maize intercropping system in northwestern China

Modern agricultural production is an energy- and carbon-intensive system. Enhancing energy and carbon efficiencies and reducing carbon footprints are important issues of sustainable development in modern agriculture. This study aimed to comprehensively assess energy and carbon budgeting and carbon footprints in wheat-maize intercropping, monoculture maize, and monoculture wheat with straw and plastic film management approaches, as based on a field experiment conducted in northwestern China. The results showed that intercropping had a greater grain yield by 12.8% and 131.0% than monoculture maize and wheat, respectively. Intercropping decreased energy and carbon inputs, increased energy and carbon outputs, thus improving energy and carbon efficiency, compared to monoculture maize. Intercropping reduced carbon footprint (CF) and yield-scale on the carbon footprint (CFy) via decreasing soil CO₂ equivalent emissions over monoculture maize. For the intercropping treatments, NTSMw/NTm (no-tillage with straw mulching and residual plastic film re-mulching) and NTSSw/NTm (no-tillage with straw standing and residual plastic film re-mulching) treatments increased grain yields by 14.9% and 13.8% over CTw/CTm (conventional tillage with no straw returning and annual new plastic film mulching). The lower energy inputs and higher energy outputs were observed in NTSMw/NTm and NTSSw/NTm treatments, thus, NTSMw/NTm and NTSSw/NTm had greater energy use efficiency by 36.9% and 34.9% than CTw/CTm. NTSMw/NTm and NTSSw/NTm treatments decreased carbon inputs and increased carbon outputs, thus improving carbon efficiency by 56.6% and 53.1%, compared to CTw/CTm. NTSMw/NTm and NTSSw/NTm treatments decreased CF by 16.8% and 14.3%, and decreased CFy by 27.6% and 24.8% compared to CTw/CTm, respectively, because of the decrease in soil CO₂ equivalent emissions. Our study indicated that system productivity, as well as energy and carbon efficiencies were enhanced, and carbon footprints were reduced by NTSMw/NTm and NTSSw/NTm treatments, and NTSMw/NTm had a more robust effect, indicating this treatment is the most sustainable cropping system in arid areas.

Optimized nitrogen rate, plant density, and irrigation level reduced ammonia emission and nitrate leaching on maize farmland in the oasis area of China

Nitrogen fertilizers play a key role in crop production to meet global food demand. Inappropriate application of nitrogen fertilizer coupled with poor irrigation and other crop management practices threaten agriculture and environmental sustainability. Over application of nitrogen fertilizer increases nitrogen gas emission and nitrate leaching. A field experiment was conducted in China's oasis irrigation area in 2018 and 2019 to determine which nitrogen rate, plant density, and irrigation level in sole maize (Zea mays L.) cropping system reduce ammonia emission and nitrate leaching. Three nitrogen rates of urea (46-0-0 of N-P2O5-K2O), at (N0 = 0 kg N ha-1, N1 = 270 kg N ha-1, and N2 = 360 kg N ha-1) were combined with three plant densities (D1 = 75,000 plants/ha-1, D2 = 97,500 plants/ha-1, and D3 = 120,000 plants/ha-1) with two irrigation levels (W1 = 5,250 m3/hm2 and W2 = 4,740 m3/hm2) using a randomized complete block design. The results showed that, both the main and interaction effects of nitrogen rate, plant density, and irrigation level reduced nitrate leaching (p < 0.05). In addition, irrigation level × nitrogen rate significantly (p < 0.05) reduced ammonia emission. Nitrate leaching and ammonia emission decreased with higher irrigation level and higher plant density. However, high nitrogen rates increased both nitrate leaching and ammonia emission. The study found lowest leaching (0.35 mg kg-1) occurring at the interaction of 270 kg N ha-1 × 120,000 plants/ha-1 × 4,740 m3/hm2, and higher plant density of 120,000 plants/ha-1 combined with 0 kg N ha-1 and irrigation level of 5,250 m3/hm2 recorded the lowest ammonia emission (0.001 kg N)-1. Overall, ammonia emission increased as days after planting increased while nitrate leaching decreased in deeper soil depths. These findings show that, though the contributory roles of days after planting, soil depth, amount of nitrogen fertilizer applied and year of cultivation cannot be undermined, it is possible to reduce nitrate leaching and ammonia emission through optimized nitrogen rate, plant density and regulated irrigation for agricultural and environmental sustainability.

N-fertilizer postponing application improves dry matter translocation and increases system productivity of wheat/maize intercropping

Intercropping increases the grain yield to feed the ever-growing population in the world by cultivating two crop species on the same area of land. It has been proven that N-fertilizer postponed topdressing can boost the productivity of cereal/legume intercropping. However, whether the application of this technology to cereal/cereal intercropping can still increase grain yield is unclear. A field experiment was conducted from 2018 to 2020 in the arid region of northwestern China to investigate the accumulation and distribution of dry matter and yield performance of wheat/maize intercropping in response to N-fertilizer postponed topdressing application. There were three N application treatments (referred as N1, N2, N3) for maize and the total amount were all 360 kg N ha-1. N fertilizer were applied at four time, i.e. prior to sowing, at jointing stage, at pre-tasseling stage, and at 15 days post-silking stage, respectively. The N3 treatment was traditionally used for maize production and allocations subjected to these four stages were 2:3:4:1. The N1 and N2 were postponed topdressing treatments which allocations were 2:1:4:3 and 2:2:4:2, respectively. The results showed that the postponed topdressing N fertilizer treatments boosted the maximum average crop growth rate (CGR) of wheat/maize intercropping. The N1 and N2 treatments increased the average maximum CGR by 32.9% and 16.4% during the co-growth period, respectively, and the second average maximum CGR was increased by 29.8% and 12.6% during the maize recovery growth stage, respectively, compared with the N3 treatment. The N1 treatment was superior to other treatments, since it increased the CGR of intercropped wheat by 44.7% during the co-growth period and accelerated the CGR of intercropped maize by 29.8% after the wheat had been harvested. This treatment also increased the biomass and grain yield of intercropping by 8.6% and 33.7%, respectively, compared with the current N management practice. This yield gain was primarily attributable to the higher total translocation of dry matter. The N1 treatment increased the transfer amount of intercropped wheat by 28.4% from leaf and by 51.6% from stem, as well as increased the intercropped maize by 49.0% of leaf, 36.6% of stem, and 103.6% of husk, compared to N3 treatment, respectively. Integrated the N fertilizer postponed topdressing to the wheat/maize intercropping system have a promotion effect on increasing the translocation of dry matter to grain in vegetative organs. Therefore, the harvest index of intercropped wheat and maize with N1 was 5.9% and 5.3% greater than that of N3, respectively. This demonstrated that optimizing the management of N fertilizer can increase the grain yield from wheat/maize intercropping via the promotion of accumulation and translocation of dry matter.

Photosynthetic Physiological Characteristics of Water and Nitrogen Coupling for Enhanced High-Density Tolerance and Increased Yield of Maize in Arid Irrigation Regions

To some extent, the photosynthetic traits of developing leaves of maize are regulated systemically by water and nitrogen. However, it remains unclear whether photosynthesis is systematically regulated via water and nitrogen when maize crops are grown under close (high density) planting conditions. To address this, a field experiment that had a split-split plot arrangement of treatments was designed. Two irrigation levels on local traditional irrigation level (high, I2, 4,050 m³ ha^-1) and reduced by 20% (low, I1, 3,240 m³ ha^-1) formed the main plots; two levels of nitrogen fertilizer at a local traditional nitrogen level (high, N2, 360 kg ha^-1) and reduced by 25% (low, N1, 270 kg ha^-1) formed the split plots; three planting densities of low (D1, 7.5 plants m^-2), medium (D2, 9.75 plants m^-2), and high (D3, 12 plants m^-2) formed the split-split plots. The grain yield, gas exchange, and chlorophyll a fluorescence of the closely planted maize crops were assessed. The results showed that water-nitrogen coupling regulated their net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), quantum yield of non-regulated non-photochemical energy loss [Y(NO)], actual photochemical efficiency of PSII [Y(II)], and quantum yield of regulated non-photochemical energy loss [Y(NPQ)]. When maize plants were grown at low irrigation with traditional nitrogen and at a medium density (i.e., I1N2D2), they had Pn, Gs, and Tr higher than those of grown under traditional treatment conditions (i.e., I2N2D1). Moreover, the increased photosynthesis in the leaves of maize in the I1N2D2 treatment was mainly caused by decreased Y(NO), and increased Y(II) and Y(NPQ). The coupling of 20%-reduced irrigation with the traditional nitrogen application boosted the grain yield of medium density-planted maize, whose Pn, Gs, Tr, Y(II), and Y(NPQ) were enhanced, and its Y(NO) was reduced. Redundancy analysis revealed that both Y(II) and SPAD were the most important physiological factors affecting maize yield performance, followed by Y(NPQ) and NPQ. Using the 20% reduction in irrigation and traditional nitrogen application at a medium density of planting (I1N2D2) could thus be considered as feasible management practices, which could provide technical guidance for further exploring high yields of closely planted maize plants in arid irrigation regions.

[Autologous stem cell transplantation improves outcomes of patients with multiple myeloma receiving proteasome inhibitors and lenalidomide treatment]

OBJECTIVE

To evaluate the effect of autologous stem cell transplantation (ASCT) on treatment response and survival outcomes in patients with newly diagnosed multiple myeloma (MM) receiving treatments with proteasome inhibitors and lenalidomide.

METHODS

We retrospectively collected the clinical data of newly diagnosed MM patients, who were eligible for ASCT and received proteasome inhibitors or lenalidomide-based treatment in our hospital from January, 2015 to December, 2019. The patients were divided into transplantation group and non-transplantation group, and in transplantation group, the patients received 4 to 6 courses of induction therapy with proteasome inhibitors or lenalidomide before ASCT, while those in the non-transplantation group received more than 8 courses of induction and consolidation therapy with proteasome inhibitors or lenalidomide-based regimens. The therapeutic efficacy and survival outcomes of the patinets were compared between the two groups.

RESULTS

A total of 105 patients were enrolled in the study, including 48 (45.7%) in transplantation group and 57 (54.3%) in non-transplantation group. The two groups were matched for gender, age and treatment response after 4 courses of induction therapy (P > 0.05). The rate of optimal response before relapse differed significantly between the two groups (P=0.000), and the patients receiving ASCT had significantly higher rates of complete response (85.4% vs 54.4%, P= 0.001) and very good partial response or better (95.8% vs 73.7%, P=0.002) than those without ASCT. At the end of follow-up, the median progression-free survival in the transplantation group was not reached, as compared with 29 months in the nontransplantation group (P=0.013). The median overall survival (OS) in the two groups was not reached, but the OS was better in the transplant group than in the non-transplant group (P=0.022).

CONCLUSION

ASCT can further improve the depth of remission and survival outcomes in patients with newly diagnosed MM receiving treatments with proteasome inhibitors and lenalidomide.

The association of metabolic health obesity with incidence of carotid artery plaque in Chinese adults

BACKGROUND AND AIMS

We aimed to evaluate the association between different obese phenotypes with carotid artery plaque (CAP) event.

METHOD AND RESULTS

The current retrospective cohort study was performed in 32,778 Chinese adults (19,221 men and 13,557 women, aged 41.9 ± 11.0 years). Obese phenotypes were assessed based on baseline body mass index (<24.0 vs. ≥24.0 kg/m²) and metabolic characteristics (health vs. unhealth). All the participants were further classified into four groups: metabolic health and normal weight (MHNW), metabolic unhealth and normal weight (MUHNW), metabolic health and overweight (MHO), and metabolic unhealth and overweight (MUHO). Ultrasound B-mode imaging was annually performed to evaluate CAP throughout the study. We have identified 2142 CAP cases during 5-year follow-up. Comparing with the MHNW group, the hazard ratios for the risk of incident CAP was 2.44 (95% CI:1.92 and 3.09) for the MUHNW group, 1.52 (95% CI:1.06 and 2.18) for the MHO group, and 1.8 (95% CI:1.4 and 2.33) for the MUHO group. The association was more pronounced in young adults (<65 y) than that in aged adults (≥65 y). Sensitivity analysis generated similar results with the main analysis.

CONCLUSION

MUHNW, MHO, and MUHO were associated with the risk of CAP.

Improving wheat grain yield via promotion of water and nitrogen utilization in arid areas

Crop yield is limited by water and nitrogen (N) availability. However, in Hexi Corridor of northwestern China, water scarcity and excessive fertilizer N in wheat (Triticum aestivum L.) production causes serious conflicts between water and N supply and crop demand. A field experiment was conducted from 2016 to 2018 to evaluate whether reducing of irrigation and fertilizer N will reduce grain yield of wheat. There were two irrigation quotas (192 and 240 mm) and three fertilizer N rates (135, 180, and 225 kg N ha⁻¹). The results showed that reducing irrigation to 192 mm and N rate to 180 kg N ha⁻¹ reduced water uptake, water uptake efficiency, and N uptake of spring wheat as compared to local practice (i.e., 240 mm irrigation and 225 kg N ha⁻¹ fertilizer). Whereas, it improved water and N utilization efficiency, and water and N productivity. Consequently, the irrigation and N rate reduced treatment achieved the same quantity of grain yield as local practice. The path analysis showed that interaction effect between irrigation and N fertilization may attributable to the improvement of grain yield with lower irrigation and N rate. The enhanced water and N utilization allows us to conclude that irrigation quota at 192 mm coupled with fertilizer N rate at 180 kg N ha⁻¹ can be used as an efficient practice for wheat production in arid irrigation areas.

Copper stimulates neonicotinoid insecticide thiacloprid degradation by Ensifer adhaerens TMX-23

AIMS

Aims of this study are to elucidate the molecular mechanism of copper-improved thiacloprid (THI) degradation by Ensifer adhaerens TMX-23 and characterize copper resistance of this strain.

METHODS AND RESULTS

Resting cells of E. adhaerens TMX-23 were used to degrade THI, with formation of THI amide and 98·31% of 0·59 mmol l^-1 THI was degraded in 100 min. The addition of copper improved the degradation of THI and showed little inhibitory effects on the growth of E. adhaerens TMX-23. E. adhaerens TMX-23 degraded THI to THI amide by nitrile hydratases (NhcA and NhpA). QPCR analysis indicated that the expression of nhpA was up-regulated in the presence of copper. E. adhaerens TMX-23 nitrile hydratases were purified, and enzyme assay of NhpA exhibited the highest NHase activity toward THI. The addition of copper activated the activity of NhcA. Soil degradation experiment indicated that E. adhaerens TMX-23 could quickly eliminate THI residual in copper-added soil.

CONCLUSIONS

Copper improved THI degradation by E. adhaerens TMX-23 was attributed to the induced expression of nhpA and activated NhcA.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study broadens the investigation of regulatory mechanism of NHase expression and provided theoretical basis for using metal-resistant microbes to degrade pesticide in heavy metal co-contaminated environments.

No Tillage With Plastic Re-mulching Maintains High Maize Productivity via Regulating Hydrothermal Effects in an Arid Region

Plastic is a valuable mulching measure for increasing crop productivity in arid environments; however, little is known about the main mechanism by which this valuable technology actuates spatial-temporal changes in soil hydrothermal effect. So a 3-year field experiment was conducted to optimize soil hydrothermal effect of maize field with three plastic mulched management treatments: (1) no tillage with plastic re-mulching (NM), (2) reduced tillage with plastic mulching (RM), and (3) conventional tillage with annual new plastic mulching (CM). The results showed that NM treatment increased soil water content by 6.6-8.4% from maize sowing to seedling stage, than did CM, and it created a good soil moisture environment for sowing of maize. Also, NM had greater soil water content by 4.8-5.6% from maize silking to early-filling stage than had CM, and it made up for the abundant demand of soil moisture for the vigorous growth of maize filling stage. The NM treatment increased water consumption (WC) before maize big-flare stage, decreased WC from big-flare to early-filling stage, and increased WC after early-filling stage. So NM treatment effectively coordinated water demand contradiction of maize at entire growing season. NM decreased soil accumulated temperature (SAT) by 7.0-13.0% at maize sowing to early-filling stage than did CM, but NM had little influence on the SAT during filling stage. In particular, the treatment on NM had smaller absolute values of air-soil temperature differences than RM and CM treatments during maize filling stage, indicating that NM treatment maintains the relative stability of soil temperature for ensuring grain filling of maize. The NM treatment allowed the maize to grow in a suitable hydrothermal status and still maintained high yield. In addition, NM treatment obtained higher net income and rate of return by 6.4-11.0% and 44.1-54.5%, respectively, than did CM, because NM treatment mainly decreased the input costs for plastic and machine operations. Therefore, the NM treatment can be recommended as a promising technique to overcome simultaneous heat stress and water shortage in arid environments.

Impact of the combined timing of PD-1/PD-L1 inhibitors and chemotherapy on the outcomes in patients with refractory lung cancer

Background

PD-1/PD-L1 inhibitors in combination with chemotherapy are widely used in clinical practice. However, the ideal combined timing of them has not been fully explored.

Methods

In this study, simulation experiments to explore the impacts of the combination of anti-PD-1 antibody (anti-PD-1 Ab) on the cytotoxic effects of chemotherapeutic drugs in peripheral blood mononuclear cells were performed. In addition, the effects of the combined timing of PD-1/PD-L1 inhibitors and chemotherapy on efficacy and safety were retrospectively analysed in patients with refractory lung cancer.

Results

Experiments in vitro showed that administering the anti-PD-1 Ab 3 days after chemotherapy (represented by dicycloplatin) resulted in significantly weaker cytotoxic effects on lymphocytes, compared with administering the anti-PD-1 Ab before or concurrent with chemotherapy. Moreover, data from 64 lung cancer patients treated with PD-1/PD-L1 inhibitors plus chemotherapy as a second- or higher-line therapy were retrospectively analysed. The results showed that administering PD-1/PD-L1 inhibitors 1-10 days (especially 3-5 days) after chemotherapy was associated with longer overall survival [17.3 months versus 12.7 months; hazard ratio (HR) = 0.58, 95% confidence interval (CI) 0.28-1.19, P = 0.137 in univariate analysis; HR = 0.36, 95% CI 0.16-0.80, P = 0.012 in multivariate analysis] and a trend of improved progression-free survival (5.1 months versus 4.2 months; HR = 0.81, 95% CI 0.42-1.54, P = 0.512) compared with administering PD-1/PD-L1 inhibitors before or concurrent with chemotherapy.

Conclusion

Our findings suggest that administering PD-1/PD-L1 inhibitors 1-10 days (especially 3-5 days) after chemotherapy is superior to administering PD-1/PD-L1 inhibitors before or concurrent with chemotherapy in patients with refractory lung cancer, but this result needs to be further explored by prospective studies.

•

The cytotoxic effects of chemotherapeutic drugs were positively correlated with the activation states of PBMCs.

•

Administering the anti-PD-1 Ab 3 days after chemotherapy resulted in weaker cytotoxic effects on lymphocytes in vitro.

•

Administering PD-1/PD-L1 inhibitors a few days after chemotherapy resulted in better survival in lung cancer patients.

95 Invitro correction of F508del and G542X mutations in sheep fibroblasts of cystic fibrosis models

Cystic fibrosis (CF) is a human genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Among the ∼2000 known CF mutations, the F508del mutation is found in 84% and G542X in 4.6% of the CF patients in the United States. The F508del mutation occurs in exon 11 and is characterised by deletion of the “CTT” nucleotides, resulting in deletion on the phenylalanine residue at the position 508 of CFTR. This causes misfolding of the CFTR protein, which is further degraded by proteases. The G542X mutation is a nonsense mutation found in exon 12 and associated with nonsense-mediated decay of the mutant transcript causing the absence of protein production. Previously, we generated CFTRF508del/F508del and CFTRG542X/G542X lambs (unpublished) using CRISPR/Cas9 and somatic cell nuclear transfer (SCNT) techniques. We hypothesised that gene editing may be an effective tool to correct these mutations and permanently cure this genetic disease. Thus, in this study, we evaluated the efficiency of CRISPR/Cas9-meditated gene knock-in to correct the F508del and G542X mutations in sheep fibroblasts invitro. We designed single guide (sg)RNAs using the Benchling software (https://benchling.com/academic) and approximately 100bp of single-stranded oligodeoxynucleotides (ssODNs) targeting the mutation sites at exon 11 and 12 to introduce either “CTT” or change the “T” to “G” nucleotide in genome of F508del or G542X CF sheep cells, respectively. Each of Cas9/sgRNA ribonucleoproteins was transfected into sheep fibroblast cells along with ssODNs using the Lonza-4D-NucleofectorTM (Lonza) system for homology-directed repair. The transfected cells were subsequently cultured in Dulbecco’s modified Eagle medium, supplemented with 15% fetal bovine serum and 1% penicillin, and incubated at 38.5°C. DNA was extracted 48h post-transfection to validate mutation efficiency. PCR products of the exons 11 and 12 were ligated into T-vector, and bacterial colonies were selected based on blue/white screening. In total, we isolated 32 single cell bacterial colonies for each mutant. Sequencing results indicate that “CTT” was introduced in 4/26 (15.3%) plasmid colonies, and “T to G” replaced in 13/31 (41.9%) colonies. Therefore, our results indicate that the F508del and G542X mutations can be effectively corrected in CF sheep fibroblasts invitro using a CRISPR/Cas9 approach.

92 Correction of the CFTR G542X mutation using CRISPR/Cas9 genome editing in ovine-bovine interspecies embryos

Cystic fibrosis (CF) is a human genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. We have recently generated 3 CF sheep models: a CFTR−/− model (Fan et al. 2018 LCI Insight 3:e123529; https://doi.org/10.1172/jci.insight.123529) and 2 additional models where we introduced human G542X and F508del mutations into the sheep genome (unpublished). Correction of CFTR mutations in zygotes with gene-editing techniques could be a permanent solution to cure this disease. To assess the efficiency of mutation correction invitro by CRISPR/Cas9, we utilised embryos generated by ovine-bovine interspecies SCNT (iSCNT) due to limited access to sheep oocytes. First, we evaluated the developmental capacity of reconstructed iSCNT embryos, in which nucleus donors were derived from ovine fibroblasts and recipient cytoplasm from enucleated bovine oocytes. These iSCNT embryos were able to develop to 16- to 32-cell stage (3/30, 10.0%), which allowed the genotyping of each embryo using PCR-restriction fragment length polymorphism assays and Sanger sequencing. Then, specific single-guide RNAs (sgRNAs) and 101-bp single-stranded oligodeoxynucleotides (ssODNs) were designed and synthesised to correct the G542X mutation in the sheep CFTR gene. We optimized the concentrations of Cas9:sgRNA ribonucleoproteins (RNPs) for 1-cell stage embryonic injection. Mutation analysis of embryos was conducted at 3 days post injection. Genotyping results showed that we achieved high efficiencies (95.7–100%) of mutations (indels) at targeting loci after injection of different concentrations of Cas9:sgRNA RNPs (0.02 µg:0.6 pmol/µL to 1.4 µg:40 pmol/µL). Furthermore, when an RNP (1.4 µg:40 pmol/µL) was co-injected with a ssODN (80 pmol/µL), both targeting the G542X mutation, the mutation was successfully corrected in the genome of iSCNT embryos generated using G542X fibroblasts as nucleus donors at an efficiency of 5.7% (3/53) via homology-directed repair mechanism. During the invitro culture of iSCNT embryos, we did not observe significant difference (P&gt;0.05, unpaired t-test) in cleavage rates between embryos with or without injection (85.5% vs. 89.0%). Off-target analysis of those mutated and G542X-corrected embryos is in progress. Our strategy overcomes the limitation of oocyte source and provides an opportunity to mimic the editing of any other gene in embryos of different species.

Strip width ratio expansion with lowered N fertilizer rate enhances N complementary use between intercropped pea and maize

Maize (Zea mays L.)/pea (Pisum sativum L.) strip intercropping is considered a promising cropping system to boost crop productivity. The 3-year (2009-2011) field experiment was conducted at Wuwei, northwest China, with two maize to pea strip width ratios (80:80 cm and 120:80 cm), each under three N fertilizer rates (0, 90 and 135 kg N ha-1 for pea, and 0, 300, and 450 kg N ha-1 for maize). The results showed that expanding maize to pea strip width ratio from 80:80 cm to 120:80 cm coupled with a reduction of N fertilizer rate intensified N competition and improved N compensation. The apparent N recovery and N utilization efficiency of intercropped pea with strip width ratio of 120:80 cm were increased by 8.0% and 8.9% compared to strip width ratio of 80:80 cm. Compared to high N rate, the two indicators of intercropped pea with lowered N rate were increased by 10.0% and 6.0%. For intercropped maize, the two indicators were increased by 6.8% and 5.1%, with strip width ratio of 120:80 cm compared to 80:80 cm. Also, they were improved by 9.7% and 11.5%, with lowered N rate compared to high N rate. Consequently, the grain yield of pea and maize in the 120:80 cm pattern was improved by 11.9% and 7.7% compared to 80:80 cm. We concluded that expanding maize to pea strip ratio coupled with N fertilizer reduction can optimize N complementary use.

Lrp6 Dynamic Expression in Tooth Development and Mutations in Oligodontia

Genes associated with the WNT pathway play an important role in the etiology of tooth agenesis. Low-density lipoprotein receptor-related protein 6 encoding gene (LRP6) is a recently defined gene that is associated with autosomal dominant inherited tooth agenesis. Here, we aimed to identify novel LRP6 mutations in patients with tooth agenesis and investigate the significance of Lrp6 during tooth development. Using whole-exome sequencing, we identified 4 novel LRP6 heterozygous mutations (c.2292G>A, c.195dup, c.1095dup, and c.1681C>T) in 4 of 77 oligodontia patients. Notably, a patient who carried a nonsense LRP6 mutation (c.2292G>A; p.W764*) presented a hypohidrotic ectodermal dysplasia phenotype. Preliminary functional studies, including bioinformatics analysis and TOP-/FOP-flash reporter assays, demonstrated that the activation of WNT/β-catenin signaling was compromised as a consequence of LRP6 mutations. RNAscope in situ hybridization revealed dynamic and special changes of Lrp6 expression during murine tooth development from E11.5 to E16.5. It was noteworthy that Lrp6 was specifically expressed in the epithelium at E11.5 to E13.5 but was expressed in both dental epithelium and dental papilla from E14.5 and persisted in both tissues at later stages. Our study broadens the mutation spectrum of human tooth agenesis and is the first to identify a LRP6 mutation in patients with hypohidrotic ectodermal dysplasia and reveal the dynamic expression pattern of Lrp6 during tooth development. Information from this study is conducive to understanding the functional significance of Lrp6 on the biological process of tooth development.

Phase transitions in the classical exchange-anisotropic Kitaev-Heisenberg model

The Kitaev model on the honeycomb lattice has been receiving substantial attention due to the discovery of quantum spin liquid state associated with this model. Consequently, its classical partners such as the Kitaev-Heisenberg (KH) model and associated phase transitions become concerned. Specifically, an intermediate Kosterlitz-Thouless (KT) phase engaged in the transition from the high-temperature (T) disordered state to the low-T sixfold degenerate state is predicted in the isotropic KH model [Phys. Rev. Lett. 109, 187201 (2012)10.1103/PhysRevLett.109.187201], but so far no sufficient experimental proof has been reported. In this work, we consider an essential extension of this KH model on the honeycomb lattice by including the Kitaev exchange anisotropy that is non-negligible in realistic materials. The associated phase transitions are thus investigated using the Monte Carlo simulations. It is found that such an anisotropy will result in a degradation of the sixfold degeneracy of the ground state in the isotropic KH model down to the fourfold or twofold degenerate ground state, and the finite-T phase transitions will also be modified remarkably. Interestingly, the intermediate KT phase can be suppressed by this Kitaev exchange anisotropy. This work thus provides a more realistic description of the physics ingredient with the KH model and presents a possible explanation on absence of the intermediate phase in real materials where the Kitaev exchange anisotropy can be more or less available.

Second harmonic generation microscopy using pixel reassignment

Second harmonic generation (SHG) microscopy is expected to be a powerful tool for observing the cellular-level functionality and morphology information of thick tissue owe to its unique imaging properties. However, the maximum attainable resolution obtainable by SHG microscopy is limited by the use of long-wavelength, near-infrared excitation. In this paper, we report the use of pixel reassignment to improve the spatial resolution of SHG microscopy. The SHG signal is imaged onto a position-sensitive camera, instead of a point detector typically used in conventional SHG microscope. The data processing is performed through pixel reassignment and subsequent deblurring operation. We present the basic principle and a rigorous theoretical model for SHG microscopy using pixel reassignment (SHG-PR). And for the first time, the optimal reassignment factor for SHG-PR is derived based on the coherent characteristics and the dependence of wavelength in SHG microscopy. To evaluate the spatial resolution improvement, images of nano-beads separated by different distances and of a microtubule array have been simulated. We gain about a 1.5-fold spatial resolution enhancement compared to conventional SHG microscopy. When a further deblurring operation is implemented, this method allows for a total spatial resolution enhancement of about 1.87. Additionally, we demonstrate the validity of SHG-PR for raw data with noise. LAY DESCRIPTION: Second harmonic generation (SHG) microscopy has emerged as a powerful imaging technique in clinical diagnostics and biological research. SHG microscopy is label-free and provides intrinsic optical sectioning for three-dimensional (3D) imaging. However, a near-infrared excitation wavelength results a restriction in the maximum attainable spatial resolution of SHG microscopy. In this paper, we present a simple resolution-enhanced SHG imaging method, SHG microscopy using pixel reassignment (SHG-PR). We demonstrate a rigorous theoretical model for SHG-PR and derive the optimal reassignment factor. The simulation result shows the clear improvement of the image resolution and contrast in the SHG-PR after deblurring operation. The FWHM value of single microtubule shows that SHG-PR enables a spatial resolution enhancement by a factor of 1.5, compared to conventional SHG microscopy. After a proper deblurring operation, this method allows for a total spatial resolution enhancement of about 1.87. The improvements of spatial resolution and contrast are still valid for raw data with noise. It is expected that this method can contribute towards new insights in unstained tissue morphology, interaction of cells, and diseases diagnosis.

Identifying a novel 5-gene signature predicting clinical outcomes in acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is the most common type of acute leukemia and biologically heterogeneous diseases with poor prognosis. Thus, we aimed to identify prognostic markers to effectively predict the prognosis of AML patients and eventually guide treatment.

METHODS

Prognosis-associated genes were determined by Kaplan-Meier and multivariate analyses using the expression and clinical data of 173 AML patients from The Cancer Genome Atlas database and validated in an independent Oregon Health and Science University dataset. A prognostic risk score was computed based on a linear combination of 5-gene expression levels using the regression coefficients derived from the multivariate logistic regression model. The classification of AML was established by unsupervised hierarchical clustering of CALCRL, DOCK1, PLA2G4A, FCHO2 and LRCH4 expression levels.

RESULTS

High FCHO2 and LRCH4 expression was related to decreased mortality. While high CALCRL, DOCK1, PLA2G4A expression was associated with increased mortality. The risk score was predictive of increased mortality rate in AML patients. Hierarchical clustering analysis of the five genes discovered three clusters of AML patients. The cluster1 AML patients were associated with lower cytogenetics risk than cluster2 or 3 patients, and better prognosis than cluster3 patients (P values < 0.05 for all cases, fisher exact test or log-rank test).

CONCLUSION

The gene panel comprising CALCRL, DOCK1, PLA2G4A, FCHO2 and LRCH4 as well as the risk score may offer novel prognostic biomarkers and classification of AML patients to significantly improve outcome prediction.

Comparison of efficacy of HCAG and CAG re-induction chemotherapy in elderly low- and intermediate-risk group patients diagnosed with acute myeloid leukemia

PURPOSE

The present study aimed to investigate the efficacy and severity of adverse effects of HCAG and CAG re-induction chemotherapy in elderly low- and intermediate-risk group patients diagnosed with acute myeloid leukemia (AML) following induction failure.

METHODS

A total of 94 AML patients were enrolled in the study, of whom 46 were treated with HCAG chemotherapy, while 48 were treated with CAG chemotherapy.

RESULT

The complete remission (CR) was 39.6% in the patients with HCAG, while the CR was 33.3% in the CAG group. The overall remission (ORR) was 63.0% and 43.5% in patients of the HCAG and CAG groups, respectively (P = 0.038). The median survival time of progression free survival (PFS) was 8.0 (95% CI 3.843-10.157) months in the HCAG group and 7.0 (95% CI 2.682-13.318) months in the CAG group (P = 0.032). A total of 31 patients in the HCAG group suffered from grade 4 hematological toxicity, whereas 29 patients were treated with CAG (P = 0.622). A total of 27 (58.7%) cases indicated apparent pulmonary infection in the HCAG group, while 25 (52.1%) were noted with this complication in the CAG group (P = 0.519). Oral cavity toxicity was evident for 13 (28.3%) and 11 (23.0%) cases in the HCAG and CAG groups, respectively (P = 0.216).

CONCLUSION

The HCAG regimen was more effective than the CAG regimen in elderly low- and intermediate-risk group patients diagnosed with acute myeloid leukemia although the HCAG regimen exhibited similar toxicity with that of the CAG group.

0718 Hypoxemia and Pulmonary Hypertension in Patients with Concomitant Restrictive Ventilatory Defect and Sleep Apnea: The Overlap Syndrome

Introduction

Patients with severe restrictive ventilatory defect (RVD) have hypoxemia and a high risk of pulmonary hypertension (PHTN). Sleep apnea (SA) aggravates the severity of nocturnal desaturation significantly. The aim of this study was to investigate the severity of hypoxemia and prevalence of PHTN in patient with the overlap syndrome (OS) of RVD and SA.

Methods

Patients referred for both sleep test and spirometry for suspected SA and RVD or obstructive ventilatory defect (OVD) were recruited prospectively from January-December, 2018. SA was determined by an apnea-hypopnea index ≥5/h; mean nocturnal oxygen saturation (meanSaO2), minimum oxygen saturation (minSaO2), saturation lower than 90% (T90) were calculated automatically. RVD was diagnosed in the presence of forced expiratory volume in the first second/forced vital capacity (FVC) &gt;0.7 and FVC&lt;80% predicted value. PHTN was defined by systolic pulmonary arterial pressure (SPAP) ≥ 50mmHg, documented by noninvasive transthoracic echocardiography. Patients with PHTN secondary to extrapulmonary factors were excluded.

Results

Of 65 patients who completed the investigation, 16 (24.6%) subjects were diagnosed with isolated SA (without RVD or OVD), and 28 (43.1%) subjects were verified to have RVD, in which 22 (78.6%) were diagnosed with OS and 6 (21.4%) presented as isolated RVD. Patients with OS vs. those with isolated RVD had lower minSaO2 (78.3% vs. 88.7%, p=0.003) and meanSaO2 (91.5% vs. 95.8%, p=0.007) but higher T90 (37.2% vs. 0.3%, p=0.009). Patients with OS vs. those with isolated RVD or with isolated SA had higher SPAP (62.6 mmHg vs. 45.3 mmHg or 35.9 mmHg, p=0.334 or p=0.016 respectively). Higher proportion of patients with OS were diagnosed with PHTN than those with isolated RVD or isolated SA (8 [36.4%] vs. 1 [16%] or 1 [6.25%], p=0.360 or p=0.031, respectively). T90 was the only polysomnographic data associated with the prevalence of PHTN after adjusting for age and sex (OR 4.90, 95% CI 1.23-25.56, p=0.023).

Conclusion

Patients with the OS of RVD and SA had high odds of PHTN, which is probably associated with severe hypoxemia. Further investigation is needed to discern whether therapeutic strategies toward OS might eliminate PHTN in this cohort.

Support

 

0061 Does Combining M1 M2 Reference Influence Amplitude of Slow Waves?

Introduction

Slow wave amplitudes are critical to determining Stage N3 sleep yet ECG artifact frequently interferes with accurate amplitude measurement. This artifact may be lessened by using a combined M1-M2 reference however theoretically this may decrease the amplitude due to shorter inter-electrode distance (predicted 27% loss). The AASM Scoring Manual recommends scoring slow wave activity using F4-M1 channel or alternatively F3-M2, but does not recognize a combined reference. This study measures the differences in slow wave amplitude using contralateral versus combine reference.

Methods

12 polysomnograms were randomly selected for analysis of amplitude of slow wave using contralateral and combined reference channels. Six separate EEG channels (F3-M1, F3-M2, F3-M1+M2, F4-M1, F4-M2, and F4-M1+M2) were used to analyze 25 different slow waves from each polysomnogram. Individual slow waves from Stage N3 sleep were analyzed using the Natus Sleepworks Amplitude Measurement Tool if their peak and trough were free EKG artifact. Averages and standard deviations of the waveforms were calculated for each patient and channel. Differences were normalized by dividing by the amplitude of the original wave using the contralateral reference.

Results

Subjects age ranged from 30–69 yrs, with 6 being females. Mean amplitudes were as follows: F3-M2 was 131.75µV, F3-M1+M2 125.84 µV, F4-M1 130.57 µV, and F4-M1+M2 128.22µV. The overall average difference of F4-M1 to F4-M1+M2 was 0.92% and the average difference of F3-M2 to F3-M1+M2 was 3.52% with the average standard deviation of 8.47%.

Conclusion

This study shows the average loss in amplitude of converting F4-M1 to F4-M1+M2 was less than 1% and 3.5% for F3-M2 to F3-M1+M2. Combining M1M2 reference may be a valuable alternative to reduce EKG artifact.

Support

None

[Specifications for diagnosis and treatment of non-neonatal tetanus]

Tetanus consists of neonatal tetanus and non-neonatal tetanus. Non-neonatal tetanus remains a serious public health problem, although neonatal tetanus has been eliminated in China since 2012. Non-neonatal tetanus is a potential fatal disease. In the absence of medical intervention, the mortality rate of severe cases is almost 100%. Even with vigorous treatment, the mortality rate is still 30%-50% globally. These specifications aim to regulate non-neonatal tetanus diagnosis and treatment in China, in order to improve medical quality and safety. These specifications introduce the etiology, epidemiology, pathogenesis, clinical manifestations and laboratory tests, diagnosis, differential diagnosis, grading and treatment of non-neonatal tetanus.

134 Generation of NANOS2 knockout goats using CRISPR/Cas9 and somatic cell nuclear transfer techniques

The NANOS2 gene, encoding an RNA binding protein, is known to play a critical role in the development of germline for all organisms studied to date. The male mice with biallelic NANOS2 knockouts (KOs) are sterile due to apoptosis of prospermatogonia shortly after birth but with morphologically intact seminiferous tubules. Thus, the choice of NANOS2 for targeting could be a viable strategy to develop germline ablated males that would serve as recipients for exogenous spermatogonial stem cell transplantation. The goat is a potential model of human physiology and an agriculturally important species. Here, we report successful generation of NANOS2 KO goats using CRISPR/Cas9 and somatic cell nuclear transfer (SCNT) techniques. We first designed 4 single-guide RNAs (sgRNAs) specific for the single exon of goat NANOS2 (GenBank: NC_030825.1). The targeting vectors were constructed by using the pX330 plasmid (Addgene: 42230) and transfected into sheep fetal fibroblasts. Mutation efficiency analysis showed that 3 of them (out of 4, 75.0%) were efficient in directing Cas9 to generate targeted cleavages, with mutation efficiencies of 10-30%. We established single cell-derived fetal fibroblast colonies by limiting dilution of the cells transfected with one of targeting vectors (sgRNA: GCTGGAGACCCAAGGGACTG). Colony screening with PCR/restriction fragment length polymorphism (RFLP) assays confirmed that we achieved biallelic mutations in the targeting site in 6 of 89 (6.7%) male and 6 of 172 (3.5%) female colonies. Sanger sequencing analysis of genomic DNA isolated from cell colonies with biallelic mutations showed that typical nucleotide deletions and insertions (indels), caused by repairing double-strand DNA breaks during the error-prone non-homologous end joining (NHEJ) process, were generated at the targeting site of NANOS2. Three male and two female colonies with NANOS2 null mutations were identified and used as cell donors for SCNT. In total, 202 cloned 1-cell stage embryos (130 male or 72 female) were generated and surgically transferred into 12 synchronized recipients. Six of them (6 of 12, 50.0%) were confirmed pregnant by ultrasonography on Day 40-45 of gestation. Four pregnancies developed to term, resulting in six offspring (five males and one female). Sequence analysis and PCR/RFLP assays showed that both male and female offspring carried the mutations in NANOS2, which were identical to the donor colonies from which they originated. Our results indicated that CRISPR/Cas9 combined with SCNT is an efficient system for generating NANOS2 KO goats. The phenotypic analysis to assess the effects of NANOS2 KO on the development of germline in male cloned goats is in progress.

132 Introduction of F508del human mutation into the CFTR gene of sheep fetal fibroblasts using CRISPR/Cas9 ribonucleoprotein

Cystic fibrosis (CF) is an autosomal recessive genetic disease that affects over 30 000 people in the United States and is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The CFTR protein is a cAMP-regulated C− channel responsible for regulation of anion transport, primarily in the epithelial cells. We have previously generated a sheep model of CF by genetically inactivating the CFTR gene (Fan et al. 2018 JCI Insight 3, e123529). The newborn CFTR −/− sheep develops severe disease consistent with CF pathology in humans. The CF model is extremely valuable for understanding the developmental aspects of CF disease, as sheep have been used extensively in the study of human fetal growth and development. Sheep, like humans, typically give birth to only one or two offspring in each pregnancy, which make them more suitable than many other species for testing prenatal gene-editing treatments. Thus, in this new study, we are working on the generation of F508del sheep CF model. The F508del mutation was chosen because it is the most common mutation in the human CFTR gene (~70%). This mutation is characterised by the deletion of the CTT nucleotides, which ultimately deletes the phenylalanine residue at position 508. The F508del mutation causes misfolding of the CFTR protein, which is further degraded by proteases. Even though several CFTR modulators are available, they are not effective in all patients. Additionally, they cannot reverse deleterious prenatal CF manifestations. Hence, this model will be valuable for evaluating both prenatal drug and gene therapies. Here, we used a CRISPR/Cas9 gene-editing approach to introduce the F508del mutation into the sheep genome. We designed an sgRNA targeting exon 11 of the sheep CFTR gene using the Benchling software (https://benchling.com/academic). The sgRNA was synthesised by Synthego and Cas9 purchased from ThermoFisher. Using the Lonza-4D-Nucleofector system, Cas9/sgRNA ribonucleoprotein complex was transfected into sheep fetal fibroblasts (SFFs), along with 100bp single-stranded oligodeoxynucleotide, flanking the F508del mutation, for the homology-directed repair. The transfected cells were subsequently cultured in Dulbecco's modified Eagle's medium, supplemented with 15% fetal bovine serum and 1% penicillin, and incubated at 38.5°C. Two days post-transfection, SFFs were seeded individually into five 96-well plates by limited dilution. After seven days, the individual colonies were expanded into 24-well plates and cultured for three more days. A total of 56 single-cell-derived SFF colonies were isolated. The presence of F508del mutation was confirmed by amplifying the PCR products of the exon 11 flanking the mutation site and subjecting each amplicon to Sanger sequencing. The sequencing results indicated that the indels (insertion/deletion) were introduced in 49 out of 56 (87.5%) of the colonies, and four (7.14%) of them were confirmed to have biallelic F508del mutations based on sequencing peaks. Therefore, we successfully introduced the F508del mutation in SFFs that will be used for the production of F508del CF sheep by somatic cell nuclear transfer.

[Specifications for diagnosis and treatment of non-neonatal tetanus]

Tetanus consists of neonatal tetanus and non-neonatal tetanus. Although neonatal tetanus in China has been eliminated since 2012, non-neonatal tetanus remains a serious public health problem. Non-neonatal tetanus is a potential fatal disease, and the mortality rate of severe cases is almost 100% in the absence of medical intervention. Even with vigorous treatment, the mortality rate is still 30~50% globally. In order to standardize the diagnosis and treatment of non-neonatal tetanus in China, this specification is hereby formulated. This standard includes etiology, epidemiology, pathogenesis, clinical manifestations, laboratory tests, diagnosis, differential diagnosis, classification, grading and treatment of non-neonatal tetanus.