Genetic variation and response to selection of photosynthetic and forage characteristics in Kentucky bluegrass (Poa pratensis L.) ecotypes under drought conditions

Introduction

Evaluation of the effects of water-limited conditions on the photosynthetic characteristics and forage yield is important for enhancing the forage productivity and drought tolerance in Kentucky bluegrass (Poa pratensis L.).

Methods

In the present study, 100 P. pratensis ecotypes collected from different geographical areas in Iran were assessed under well-watered and drought stress conditions. Genetic variation and response to selection for the photosynthetic characteristics [i.e., net photosynthesis rate (A), stomatal conductance (gs), transpiration rate (Tr), chlorophyll content (Chl), and photochemical efficiency (Fv/Fm)] and forage yield [fresh forage yield (FY) and dry forage yield (Dy)] traits were analyzed during the 2018 and 2019 growing seasons.

Results and discussion

Drought stress had negative effects on evaluated photosynthesis parameters and significantly reduced dry and fresh forage yields. On average, FY with a 45% decrease and gs with a 326% decrease under drought stress conditions showed the highest reduction rate among forage yield and photosynthesis traits, respectively. Genotypic coefficients of variation (GCV) for FY were lower under drought stress. The estimates of heritability, genetic advance, and genetic advance as percentage of mean showed the predominance of additive gene action for the traits. Overall, the results showed that "Ciakhor", "Damavand", "Karvandan", "Basmenj", "Abr2", "Abrumand", "Borhan", "Hezarkanian", "LasemCheshmeh", "Torshab", and "DoSar" have higher forage yield production with little change between two irrigation regimes, which makes them promising candidates for developing high-yielding drought-tolerant varieties through breeding programs.

Single-Voxel MR Spectroscopy of Gliomas with s-LASER at 7T

BACKGROUND AND PURPOSE

Magnetic resonance spectroscopy (MRS)-a method of analysing metabolites in vivo-has been utilized in several studies of brain glioma biomarkers at lower field strengths. At ultra-high field strengths, MRS provides an improved signal-to-noise-ratio and spectral resolution, but 7T studies on patients with gliomas are sparse. The purpose of this exploratory study was to evaluate the potential clinical implication of the use of single-voxel MRS at 7T to assess metabolic information on lesions in a pilot cohort of patients with grade II and III gliomas.

METHODS

We scanned seven patients and seven healthy controls using the semi-localization by adiabatic-selective refocusing sequence on a Philips Achieva 7T system with a standard dual-transmit head coil. The metabolic ratios were calculated relative to water and total creatine. Additionally, 2-hydroxyglutarate (2-HG) MRS was carried out in four of the patients, and the 2-HG concentration was calculated relative to water.

RESULTS

When comparing the tumour data to control regions in both patients and healthy controls, we found that the choline/creatine and myo-inositol/creatine ratios were significantly increased and that the N-acetylaspartate/creatine and the neurotransmitter glutamate/creatine ratios were significantly decreased. The N-acetylaspartate/water and glutamate/water ratios were also significantly decreased. The lactate/water and lactate/creatine ratios showed increases, although not significant. The GABA/water ratio was significantly decreased, but the GABA/creatine ratio was not. MRS spectra showed the presence of 2-HG in three of the four patients studied. Three of the patients, including the MRS 2-HG-negative patient, were operated on, and all of them had the IDH mutation.

CONCLUSION

Our findings were consistent with the existing literature on 3T and 7T MRS.

Identifying the source of spurious signals caused by B0 inhomogeneities in single-voxel 1 H MRS

Purpose

Single‐voxel MRS (SV MRS) requires robust volume localization as well as optimized crusher and phase‐cycling schemes to reduce artifacts arising from signal outside the volume of interest. However, due to local magnetic field gradients (B₀ inhomogeneities), signal that was dephased by the crusher gradients during acquisition might rephase, leading to artifacts in the spectrum. Here, we analyzed this mechanism, aiming to identify the source of signals arising from unwanted coherence pathways (spurious signals) in SV MRS from a B₀ map.

Methods

We investigated all possible coherence pathways associated with imperfect localization in a semi‐localized by adiabatic selective refocusing (semi‐LASER) sequence for potential rephasing of signals arising from unwanted coherence pathways by a local magnetic field gradient. We searched for locations in the B₀ map where the signal dephasing due to external (crusher) and internal (B₀) field gradients canceled out. To confirm the mechanism, SV‐MR spectra (TE = 31 ms) and 3D‐CSI data with the same volume localization as the SV experiments were acquired from a phantom and 2 healthy volunteers.

Results

Our analysis revealed that potential sources of spurious signals were scattered over multiple locations throughout the brain. This was confirmed by 3D‐CSI data. Moreover, we showed that the number of potential locations where spurious signals could originate from monotonically decreases with crusher strength.

Conclusion

We proposed a method to identify the source of spurious signals in SV ¹H MRS using a B₀ map. This can facilitate MRS sequence design to be less sensitive to experimental artifacts.

Assessing the potential of native ecotypes of Poa pratensis L. for forage yield and phytochemical compositions under water deficit conditions

Evaluation of forage yield and antioxidant activity in Poa pratensis with high quality and good spring green-up forage might help variety improvement for use under water deficit condition. Germplasm and phenotypic diversity evaluations lay a foundation for genotype selection and improvement of varieties for drought tolerance in P. pratensis. The present study was conducted to assess the genetic potential of a collection of P. pratensis accessions for drought stress and to identify the association between polyphenol compounds and forage yield traits. Vegetative clone samples of 100 accessions collected from a diverse geographical area of Iran were clonally propagated in a greenhouse and evaluated in the field under two moisture regimes (non-stress and drought stress) in 2018 and 2019. Drought stress had negative effects on fresh and dry forage yields and reduced phenotypic variances. On average, drought stress reduced fresh and dry forage yields by 45% and 28%, respectively. The results of Mantel test showed no significant correlation between forage yield traits and geographical distances. Genetic coefficients of variation for forage yield and most of the phytochemicals were lower under drought stress, suggesting that deficit irrigation may reduce genetic variation for the tested traits. The estimates of heritability were higher under non-stress conditions than under drought stress treatment for forage yield traits and few polyphenols. However, the majority of polyphenol compounds had higher heritability than forage yield traits under drought stress, which suggests the potential for indirect selection. The 'Ciakhor', 'Damavand', 'Karvandan', 'Abrumand', and 'Abr2' accessions had high quantities for polyphenols and yield traits under both moisture regimes. These accessions are promising candidates for use in variety crossing programs and for developing high-yielding varieties under water-deficit conditions.

Comparison of 2-Hydroxyglutarate Detection With sLASER and MEGA-sLASER at 7T

The onco-metabolite 2-hydroxyglutarate (2HG), a biomarker of IDH-mutant gliomas, can be detected with ¹H MR spectroscopy (¹H-MRS). Recent studies showed measurements of 2HG at 7T with substantial gain in signal to noise ratio (SNR) and spectral resolution, offering higher specificity and sensitivity for 2HG detection. In this study, we assessed the sensitivity of semi-localized by adiabatic selective refocusing (sLASER) and J-difference MEsher-GArwood-semi-LASER (MEGA-sLASER) for 2HG detection at 7T. We performed spectral editing at long TE using a TE-optimized sLASER sequence (110 ms) and J-difference spectroscopy using MEGA-sLASER (TE = 74ms) in phantoms with different 2HG concentrations to assess the sensitivity of 2HG detection. The robustness of the methods against B₀ inhomogeneity was investigated. Moreover, the performance of these two techniques was evaluated in four patients with IDH1-mutated glioma. In contrary to MEGA-sLASER, sLASER was able to detect 2HG concentration as low as 0.5 mM. In case of a composite phantom containing 2HG with overlapping metabolites, MEGA-sLASER provided a clean 2HG signal with higher fitting reliability (lower %CRLB). The results demonstrate that sLASER is more robust against field inhomogeneities and experimental or motion-related artifacts which promotes to adopt sLASER in clinical implementations.

The Clinical Course and Prognostic Factors of COVID-19 in Patients with Chronic Kidney Disease, A Study in Six Centers

INTRODUCTION

Coronavirus disease 19 (COVID-19), has recently emerged as a great health challenge. The novel corona virus may affect the kidneys mainly as acute kidney injury (AKI). Also, the outcome of COVID-19 may be different in patients with underlying kidney disease. The aim of this study was to compare the outcome of COVID-19 in patients with and without underlying kidney disease.

METHODS

This was a retrospective study on 659 hospitalized COVID-19 patients in six centers of Iran. Patients were classified into kidney (chronic kidney disease (CKD), end-stage kidney disease (ESKD) or kidney transplantation) and non-kidney groups. The clinical conditions and laboratory data were extracted from the charts. Outcome was defined as death during hospitalization or within 30 days of discharge.

RESULTS

Among 659 COVID-19 patients (mean age: 60.7 ± 16.4, 56% male), 208 were in the kidney group (86 ESKD, 35 kidney transplants, and 87 CKD patients). AKI occurred in 41.8%. Incidence of AKI was 34.7% in non-kidney, 74.7% in CKD, and 51.4% in kidney transplant patients (P < .001). Totally 178 patients (27%) died and mortality rate was significantly higher in CKD patients (50.6 vs. 23.4%, P < .001). AKI was associated with increased mortality rate (OR = 2.588, CI: 1.707 to 3.925). Initial glomerular filtration rate (GFR) < 44.2 mL/min and elevated lactate dehydrogenase (LDH) and C-reactive protein (CRP) had significant association with mortality.

CONCLUSION

We showed a higher mortality rate in COVID-19 patients with AKI and CKD. Low initial GFR and elevated LDH and CRP were associated with high mortality in COVID-19 patients.

Bioinspired Device Improves The Cardiogenic Potential of Cardiac Progenitor Cells

OBJECTIVE

Functional cardiac tissue engineering holds promise as a candidate approach for myocardial infarction. Tissue engineering has emerged to generate functional tissue constructs and provide an alternative means to repair and regenerate damaged heart tissues.

MATERIALS AND METHODS

In this experimental study, we fabricated a composite polycaprolactone (PCL)/gelatine electrospun scaffold with aligned nanofibres. The electrospinning parameters and optimum proportion of the PCL/ gelatine were tested to design a scaffold with aligned and homogenized nanofibres. Using scanning electron microscopy (SEM) and mechanophysical testes, the PCL/gelatine composite scaffold with a ratio of 70:30 was selected. In order to simulate cardiac contraction, a developed mechanical loading device (MLD) was used to apply a mechanical stress with specific frequency and tensile rate to cardiac progenitor cells (CPCs) in the direction of the aligned nanofibres. Cell metabolic determination of CPCs was performed using real-time polymerase chain reaction(RT-PCR).

RESULTS

Physicochemical and mechanical characterization showed that the PCL/gelatine composite scaffold with a ratio of 70:30 was the best sample. In vitro analysis showed that the scaffold supported active metabolism and proliferation of CPCs, and the generation of uniform cellular constructs after five days. Real-time PCR analysis revealed elevated expressions of the specific genes for synchronizing beating cells (MYH-6, TTN and CX-43) on the dynamic scaffolds compared to the control sample with a static culture system.

CONCLUSION

Our study provides a robust platform for generation of synchronized beating cells on a nanofibre patch that can be used in cardiac tissue engineering applications in the near future.

Breast cancer risk factors in Iran: a systematic review & meta-analysis

OBJECTIVES

Breast cancer is known as one of the deadliest forms of cancer, and it is increasing globally. There are a variety of proven and controversial risk factors for this malignancy. Herein, we aimed to undertake a systematic review and meta-analysis focus on the epidemiology of breast cancer risk factors in Iran.

METHODS

We performed a systematic search via PubMed, Scopus, Web of Science, and Persian databases for identifying studies published on breast cancer risk factors up to March 2019. Meta-analyses were done for risk factors reported in more than one study. We calculated odds ratios (ORs) with corresponding 95% confidence intervals (CIs) using a fixed/random-effects models.

RESULTS

Thirty-nine studies entered into the meta-analysis. Pooling of ORs showed a significant harmful effect for risk factors including family history (OR: 1.80, 95%CI 1.47-2.12), hormonal replacement therapy (HRT) (OR: 5.48, 95%CI 0.84-1.74), passive smokers (OR: 1.68, 95%CI 1.34-2.03), full-term pregnancy at age 30 (OR: 3.41, 95%CI 1.19-5.63), abortion (OR: 1.84, 95%CI 1.35-2.33), sweets consumption (OR: 1.71, 95%CI 1.32-2.11) and genotype Arg/Arg (crude OR: 1.59, 95%CI 1.07-2.10), whereas a significant protective effect for late menarche (OR: 0.58, 95%CI 0.32-0.83), nulliparity (OR: 0.68, 95%CI 0.39-0.96), 13-24 months of breastfeeding (OR: 0.68, 95%CI 0.46-0.90), daily exercise (OR: 0.59, 95%CI 0.44-0.73) and vegetable consumption (crude OR: 0.28, 95%CI 0.10-0.46).

CONCLUSIONS

This study suggests that factors such as family history, HRT, passive smokers, late full-term pregnancy, abortion, sweets consumption and genotype Arg/Arg might increase risk of breast cancer development, whereas late menarche, nulliparity, 13-24 months breastfeeding, daily exercise and vegetable consumption had an inverse association with breast cancer development.

A comparison of in vivo MRI based cortical myelin mapping using T1w/T2w and R1 mapping at 3T

In this manuscript, we compare two commonly used methods to perform cortical mapping based on myelination of the human neocortex. T1w/T2w and R1 maps with matched total acquisition times were obtained from a young cohort in randomized order and using a test–retest design. Both methodologies showed cortical myelin maps that enhanced similar anatomical features, namely primary sensory regions known to be myelin rich. T1w/T2w maps showed increased robustness to movement artifacts in comparison to R1 maps, while the test re-test reproducibility of both methods was comparable. Based on Brodmann parcellation, both methods showed comparable variability within each region. Having parcellated cortical myelin maps into VDG11b areas of 4a, 4p, 3a, 3b, 1, 2, V2, and MT, both methods behave identically with R1 showing an increased variability between subjects. In combination with the test re-test evaluation, we concluded that this increased variability between subjects reflects relevant tissue variability. A high level of correlation was found between the R1 and T1w/T2w regions with regions of higher deviations being co-localized with those where the transmit RF field deviated most from its nominal value. We conclude that R1 mapping strategies might be preferable when studying different population cohorts where cortical properties are expected to be altered while T1w/T2w mapping will have advantages when performing cortical based segmentation.

Neuroprotective effects of hyperbaric oxygen (HBO) therapy on neuronal death induced by sciatic nerve transection in rat

Background

Recent studies shows that hyperbaric oxygen (HBO) therapy exerts some protective effects against neural injuries. The purpose of this study was to determine the neuroprotective effects of HBO following sciatic nerve transection (SNT).

Methods

Rats were randomly divided into five groups (n = 14 per group): Sham-operated (SH) group, SH + HBO group, SNT group, and SNT + pre- and SNT + post-HBO groups (100% oxygen at 2.0 atm absolute, 60 min/day for five consecutive days beginning on 1 day before and immediately after nerve transaction, respectively). Spinal cord segments of the sciatic nerve and related dorsal root ganglions (DRGs) were removed 4 weeks after nerve transection for biochemical assessment of malodialdehyde (MDA) levels in spinal cord, biochemical assessment of superoxide dismutase (SOD) and catalse (CAT) activities in spinal cord, immunohistochemistry of caspase-3, cyclooxigenase-2 (COX-2), S100beta (S100ß), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) in spinal cord and DRG.

Results

The results revealed that MDA levels were significantly decreased in the SNT + pre-HBO group, while SOD and CAT activities were significantly increased in SNT + pre- and SNT + post-HBO treated rats. Attenuated caspase-3 and COX-2 expression, and TUNEL reaction could be significantly detected in the HBO-treated rats after nerve transection. Also, HBO significantly increased S100ß expression.

Conclusions

Based on these results, we can conclude that pre- and post-HBO therapy had neuroprotective effects against sciatic nerve transection-induced degeneration.

Peanut-based ready-to-use therapeutic food: acceptability among malnourished children and community workers in Bangladesh

OBJECTIVES

To assess the acceptability of a ready-to-use therapeutic food (Plumpy'nut(®) [PPN]) among 1) care givers of malnourished children and 2) community health workers (CHWs) at a nutrition rehabilitation centre in an urban slum in Dhaka, Bangladesh.

METHODS

This was a cross-sectional semi-structured questionnaire survey conducted between April and June 2011 as part of a nutritional programme run by Médecins Sans Frontières. The study population included care givers of malnourished children aged 6-59 months who received PPN for at least 3 weeks, and CHWs.

RESULTS

Of the 149 care givers (93% female) interviewed, 60% expressed problems with PPN acceptability. Overall, 43% perceived the child's dissatisfaction with the taste, 31% with consistency and 64% attributed side effects to PPN (nausea, vomiting, loose motion, diarrhoea, abdominal distension and pain). It is to be noted that 47% of children needed encouragement or were forced to eat PPN, while 5% completely rejected it after 3 weeks. Of the 29 CHWs interviewed, 48% were dissatisfied with PPN's taste and consistency, and 55% with its smell. However, 91% of the care givers and all CHWs still perceived a therapeutic benefit of PPN for malnourished children.

CONCLUSION

Despite a therapeutic benefit, only 4 in 10 care givers perceived PPN as being acceptable as a food product, which is of concern.

Severe malnutrition in children presenting to health facilities in an urban slum in Bangladesh

SETTING

An urban slum in Kamrangirchar, Bangladesh.

OBJECTIVES

Among children aged 6-59 months seeking medical care from the two Médecins Sans Frontières-supported primary health centres, to determine 1) the prevalence of severe acute malnutrition (SAM) and severe chronic malnutrition (SCM), and 2) the extent of overlap between SAM and SCM.

DESIGN

In a retrospective record review, data were analysed from out-patient registers on age, sex, height, weight and mid-upper arm circumference (MUAC) of children attending for medical care from April to September 2011. SAM was defined as weight for height < -3 Z scores of the median and/or MUAC <115 mm. SCM was defined as height for age < -3 Z scores of the median. World Health Organization growth standards were used as reference.

RESULTS

Data were complete in the records of 7318 (98%) children, of whom 322 (4%) had SAM and 1698 (23%) had SCM. Among the 322 children with SAM, 162 (50%) also had SCM.

CONCLUSION

In an urban Bangladesh slum, SAM and SCM co-exist, with a predominance of SCM. The current national guidelines for severe malnutrition, which focus on identification and management only for SAM, urgently need to be expanded to include SCM if substantial childhood morbidity and mortality are to be reduced.

Stereo-controlled Deamination of Ketoaziridines Using Ph3P/I2

PPh3/I2 is an efficient reagent for the stereo-controlled deamination of non-activated aziridines, N–H and N-alkyl aziridines, using. The method works gives the corresponding trans-alkenes from both cis and trans-aziridines. A plausible mechanism is proposed for the ring opening and deamination of keto-aziridines in the presence of Ph3P/I2.

Does the 65 cm height cut-off as age proxy exclude children eligible for nutritional assessment in Bangladesh?

SETTING

Kamrangirchar slum, Dhaka, Bangladesh.

OBJECTIVE

During nutritional surveys and in circumstances when it is difficult to ascertain children's age, length/height cut-offs are used as proxy for age to sample children aged 6-59 months. In a context of prevalent stunting, using data from primary health care centres where age and height parameters were well-recorded, we assessed the proportion of children aged between 6 and 59 months who would be excluded from nutritional assessment using a height cut-off of 65 cm as a proxy for age ≥6 months.

DESIGN

This was a secondary data analysis of primary health centre data.

RESULTS

A total of 2060 children were included in the analysis, with a median age of 24 months and a median height of 78 cm (SD 12.1, range 50-109 cm). There were 240 (12%, 95%CI 10-13) children aged between 6 and 29 months, with a height <65 cm. The majority (59%) of these children were females; 97.5% were aged 6-17 months.

CONCLUSION

In an urban slum setting in Bangladesh, the use of the current height cut-off as a proxy for age excludes vulnerable children from nutritional assessment and could also lead to underestimation of the prevalence of malnutrition in nutritional surveys.

Detection of enterotoxigenic K99 (F5) and F41 from fecal sample of calves by molecular and serological methods

Enterotoxigenic Escherichia coli (ETEC) is one of the major causes of neonatal calf diarrhea. Almost all ETEC bacteria are known to adhere to receptors on the small intestinal epithelium via their fimbriae, (F5 (K99) and F41).This study was undertaken to investigate the phenotypic and genotypic screening of virulence genes in E. coli K99 and F41. During January 2008 to December 2009, 298 diarrheic neonatal calves at 1-30 days old were studied by multiplex PCR, isolation, and serological grouping. Of the 298 diarrheic samples, 268 E. coli were isolated, of which 16 samples (5.3%) were positive for having the F5 (K99) fimbrial gene by PCR while all of the E. coli isolates also carried F41 fimbrial genes. Twenty-five percent of the isolates were proven not to be toxigenic as they did not possess the STa enterotoxin gene.