Low Resistance Group Research Articles

Slowing lung deflation by increasing the expiratory resistance enhances FRC in preterm rabbits.

As very preterm infants have surfactant-deficient and highly incompliant lungs, slowing lung deflation during expiration might help preserve functional residual capacity(FRC) during lung aeration. In this study, we investigated the effect of expiratory resistance(Re) on lung aeration during positive pressure ventilation in preterm rabbits immediately after birth. Preterm rabbit pups were delivered at 29 days gestation, mechanically ventilated from birth and simultaneously imaged to measure lung aeration using phase-contrast X-ray. Re was varied by altering the length (0, 60 or 1000 mm) of the expiratory circuit. Increasing Re led to a decrease in lung deflation rates and both peak expiratory flows and flow rates at mid-deflation. As a result, the rate of de-acceleration(slowing) in lung deflation when approaching FRC was markedly reduced with increasing resistance. During lung aeration, FRC was significantly different between resistance groups and was significantly higher over time in the high compared to the low resistance group. While FRC values tended to be higher with higher Re, they were not significantly different at end-ventilation (t = 7 min). Increasing Re of the ventilation circuit during lung aeration in preterm rabbits immediately after birth decreased lung deflation rates and increased the accumulation of FRC over time. The expiratory phase of the ventilatory cycle has been largely overlooked as an opportunity to improve ventilation in preterm infants after birth. Increasing the expiratory resistance of the ventilator circuit during lung aeration in preterm rabbits immediately after birth markedly decreased lung deflation rates and increased FRC accumulation, compared to a low expiratory resistance. This indicates that ventilation devices that reduce the "work of breathing" by reducing the expiratory resistance, may have the unintended effect of reducing FRC, particularly in extremely preterm infants that have surfactant deficient highly incompliant lungs.

Expression network analysis of bovine skin infested with Rhipicephalus australis identifies pro-inflammatory genes contributing to tick susceptibility

The skin is the primary feeding site of ticks that infest livestock animals such as cattle. The highly specialised functions of skin at the molecular level may be a factor contributing to variation in susceptibility to tick infestation; but these remain to be well defined. The aim of this study was to investigate the bovine skin transcriptomic profiles of tick-naïve and tick-infested cattle and to uncover the gene expression networks that influence contrasting phenotypes of host resistance to ticks. RNA-Seq data was obtained from skin of Brangus cattle with high (n = 5) and low (n = 6) host resistance at 0 and 12 weeks following artificial tick challenge with Rhipicephalus australis larvae. No differentially expressed genes were detected pre-infestation between high and low resistance groups, but at 12-weeks there were 229 differentially expressed genes (DEGs; FDR < 0.05), of which 212 were the target of at least 1866 transcription factors (TFs) expressed in skin. Regulatory impact factor (RIF) analysis identified 158 significant TFs (P < 0.05) of which GRHL3, and DTX1 were also DEGs in the experiment. Gene term enrichment showed the significant TFs and DEGs were enriched in processes related to immune response and biological pathways related to host response to infectious diseases. Interferon Type 1-stimulated genes, including MX2, ISG15, MX1, OAS2 were upregulated in low host resistance steers after repeated tick challenge, suggesting dysregulated wound healing and chronic inflammatory skin processes contributing to host susceptibility to ticks. The present study provides an assessment of the bovine skin transcriptome before and after repeated tick challenge and shows that the up-regulation of pro-inflammatory genes is a prominent feature in the skin of tick-susceptible animals. In addition, the identification of transcription factors with high regulatory impact provides insights into the potentially meaningful gene–gene interactions involved in the variation of phenotypes of bovine host resistance to ticks.

Mapping Chemo-Resistance Profiles of Pediatric Acute Leukemia through Integration of Ex-Vivo Drug Screens with Molecular Data

Introduction While novel approaches for treatment of acute lymphoblastic leukemia (ALL) in children have resulted in significant improvements in survival rates, survivors are faced with potentially life-long challenges as a result of the highly toxic treatment and the outcome for patients who relapse remains poor. The current risk-adapted treatment for ALL in children includes multiple drugs administered sequentially or in combination, with little variation in timing or intensity. Factors that affect varying treatment response between patients and cellular mechanisms that underly response to individual drugs are still under exploration. In this study, we investigate the relationship between ex-vivo drug resistance, transcriptomes, epigenomes and clinical outcome, with the aim of better understanding underlying determinants of treatment response. Methods Pediatric patients diagnosed with B-ALL between 1992 and 2008 in the Nordic countries were included in the study (n = 598). For these patients, ex-vivo drug response to ten clinically used drugs was determined using the fluorometric microculture cytotoxicity assay (FMCA). Clinical data, including follow-up information (overall survival and relapse free survival) was available for all patients. Additionally, DNA-methylation (450K array, n = 383) and gene expression profiling (RNA-seq, n = 119) was performed on a subset of diagnostic patient samples. The patients were stratified into low, medium and high resistance groups based on ex-vivo drug response. The low and high resistance groups were compared with regard to differentially methylated CpG sites or expressed genes associated with individual drug response profiles. Results Overall survival was significantly lower for patients with higher ex-vivo drug resistance to dexamethasone, doxorubicin and thioguanine compared to patients that displayed sensitivity to these drugs (p &amp;lt; 0.05). Similarly, relapse free survival was significantly lower for patients with ex-vivo resistance to cytarabine, dexamethasone, doxorubicin, prednisolone and thioguanine (p &amp;lt; 0.05). After adjusting for sex and risk group, according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) protocol, in a Cox proportional hazards model, higher hazard ratios for relapse were observed in the highly resistant group across all drugs. We identified distinct DNA methylation and gene expression patterns in patients with low and high resistance, indicating the presence of predetermined molecular resistance fates. These resistance patterns included 665 genes that were differentially expressed (absolute log2FC &amp;gt; 1, Benjamini-Hochberg adjusted p value &amp;lt; 0.05) and 1 422 CpG sites with differential methylation status (absolute mean β-value difference &amp;gt; 0.2, Benjamini-Hochberg adjusted p value &amp;lt; 0.05) in resistant compared to sensitive groups, for one or multiple drugs. With the aim of identifying the genes with the largest impact on drug resistance, we selected the most differentially expressed genes and the genes with the largest difference in methylation status between resistant and sensitive samples. Among these, we identified ~20 putative genes of interest for future studies into resistance mechanisms based on potential functional prioritization. Conclusion Our findings confirm that drug response profiles are associated with outcome in pediatric ALL, reflecting response in vivo. We show molecular evidence for differentiating low- and high-resistant types based on diagnostic gene expression and DNA methylation profiles, suggesting contribution of certain molecular signatures to drug response. Our data integrating molecular data with drug response profiles may help identifying such changes of importance in drug resistance mechanisms.

The Role of Small Nucleolar RNAs As Putative Biomarkers of Chemoresistance in Pediatric Acute Lymphoblastic Leukemia

Background Many previous studies have focused on the molecular landscape of pediatric acute lymphoblastic leukemia (ALL) with the aim to identify genetic changes related to disease development and outcome. However, the functional role of non-coding RNAs (ncRNAs) in leukemogenesis and treatment response is not fully understood. A group of ncRNAs known as small nucleolar RNAs (snoRNAs) regulates ribosomal biosynthesis, RNA splicing, and performs microRNA-like functions that affect post-translational gene expression. These functionalities can be dysregulated in cancer. The aim of this study was to explore the relationship between snoRNA expression and ex-vivo drug resistance in a cohort of pediatric ALL patients enrolled in the Nordic Society of Pediatric Hematology and Oncology (NOPHO) protocols. Methods We analyzed 119 B-ALL patients who were treated according to two consecutive NOPHO protocols (1992 and 2000). B-cells (CD19+) and T-cells (CD3+) from healthy blood donors were used as controls (n = 10). We stratified patients into low-, medium-, and high-resistance groups by ex-vivo drug screening using 10 commonly used chemotherapeutic drugs with the fluorometric microculture cytotoxicity assay (FMCA). RNA sequencing (RNA-seq) data were generated for all patients. Pairwise comparisons (Benjamini-Hochberg (BH) corrected Mann-Whitney U test) were conducted between the low and high resistance groups to detect differentially expressed genes. We selectively retained the differentially expressed snoRNAs for downstream analysis. BH corrected Kruskal-Wallis H and Mann-Whitney U tests were performed to compare the snoRNA expression levels for the three drug resistance groups, and between the ALL and control samples, respectively. Results We identified a set of 23 unique significantly upregulated snoRNAs (p-adjusted value &amp;lt; 0.05 and absolute log2FC&amp;gt;1) in the high-resistance group for one or multiple drugs: amsacrine (ams, n = 10), etoposide (eto, n = 10), tioguanine (thio, n = 8) and mitoxantrone (mito, n = 1). Among these genes, five snoRNAs ( SNORA30, SNORA33, SNORA36C, SNORA62 and SNORA66) were overexpressed in patients resistant to ams and eto, and one snoRNA ( SNORD27) in patients resistant to ams and mito. Gene annotation revealed 22 significantly differentially expressed snoRNAs residing within the intronic region of 20 host genes, either protein coding (including ribosomal genes) or long ncRNAs. Three snoRNAs ( SNORD22-eto, SNORD26-ams and SNORD27-ams and mito) arise from the same host gene ( SNHG1). Of the 23 differentially expressed snoRNAs, the majority (n = 18) were not differentially expressed between the ALL and control samples (BH corrected Mann-Whitney U test p-value ≥ 0.05). The expression of the host genes did not differ among the resistance groups (BH corrected Kruskal-Wallis H test p-value ≥ 0.05). However, we found that 14 of the host genes were differentially expressed between the ALL samples and controls (BH corrected Mann-Whitney U test p-value &amp;lt; 0.05). Conclusions This study is one of the first to focus on the role of snoRNAs and ex-vivo drug resistance in pediatric ALL. Our findings highlight substantial variations in snoRNA expression across the three resistance groups, underscoring the potential role of snoRNAs in modulating drug response. Importantly, our analysis indicates that the differential expression of snoRNAs in the resistance groups cannot be solely attributed to host gene expression, implying that targeting pathways involving host genes might not be the most effective approach. Rather than concentrating on pathways involving host genes, our results suggest that understanding the mechanisms of action of snoRNAs could provide promising avenues for developing novel therapeutic targets to enhance drug response in pediatric ALL.

DRD2, DRD3, and HTR2A Single-Nucleotide Polymorphisms Involvement in High Treatment Resistance to Atypical Antipsychotic Drugs.

The objective of this study was to investigate the DRD2 rs1800497, rs1799732, rs1801028, DRD3 rs6280, and HTR2A rs6314, rs7997012, and rs6311 single-nucleotide polymorphism (SNP) correlations with resistance to second-generation antipsychotics (SGAs) in a real-world sample of patients with treatment-resistant mental disorders. We divided 129 participants into a high treatment resistance (HTR) group (current treatment with two SGAs, or clozapine, or classic neuroleptics for a failure of previous SGAs trials) and a low treatment resistance (LTR) group (current treatment with one atypical antipsychotic). We used Next-Generation Sequencing on DNA isolated from peripheral blood samples to analyze the polymorphisms. We performed logistic regression to search for predictors of HTR membership. A diagnosis of schizophrenia significantly predicted the HTR membership compared to other diagnoses. Other predictors were the DRD3 rs6280 C|T (OR = 22.195) and T|T (OR = 18.47) vs. C|C, HTR2A rs7997012 A|G vs. A|A (OR = 6.859) and vs. G|G (OR = 2.879), and DRD2 rs1799732 I|I vs. D|I (OR = 12.079) genotypes. A diagnosis of schizophrenia and the DRD2 rs1799732, DRD3 rs6280, and HTR2A rs7997012 genotypes can predict high treatment resistance to SGAs.

Evaluating a Vibratory Positive Expiratory Pressure (PEP) Device as a Dysphonia Treatment

<h2>Summary</h2><h3>Introduction</h3> Previous work investigating Acapella Choice, a vibratory positive expiratory pressure device, as a form of semi-occluded vocal tract exercise (SOVTE) identified that it promoted large oscillatory pressures and promoted improved vocal economy for normophonic volunteers. Its use in a pathological population has not yet been investigated. <h3>Objectives</h3> To assess the impact of Acapella Choice as an SOVTE in a group of dysphonic patients and compare outcomes to tube-in-water resistance therapy. <h3>Methods</h3> Thirty participants underwent acoustic, electroglottography (EGG) and aerodynamic assessment before and after 3 minutes of phonation with Acapella Choice and with a 9 mm diameter tube in 5 cm of water (WRT). During exercise, aerodynamic and EGG signals were captured simultaneously. Descriptive statistics and tests of significant differences between groups and exercises were carried out. Outcome variables included expert-rated voice quality, sound pressure level, difference in first and second harmonics (H1-H2), cepstral peak prominence, mean contact quotient (CQ), mean peak pressure, mean flow during voicing, laryngeal resistance and aerodynamic power. Participants rated their perceived vocal clarity, strength, and effortlessness as well as vocal tract discomfort utilizing the Vocal Tract Discomfort Scale. <h3>Results and Conclusions</h3> Participants were clustered based on baseline laryngeal resistance, resulting in a high resistance (HR, n = 14) and low resistance (LR, n = 16) groups. Acapella produced twice the static intraoral pressure and oscillatory (root mean square) pressure and flow compared to WRT. Both exercises produced similar static flows. Acapella oscillation frequency was higher than WRT bubbling, but not meaningfully. Flow increased significantly from pre-intervention levels to perform both exercises, and further increased during the task. The glottal response of the groups was categorically different; the HR group had an immediate drop in CQ commencing both tasks, while the LR group demonstrated a steady decline in CQ in Acapella only. Following Acapella, CQ and H1-H2 trended towards normalization. Acapella also produced larger aerodynamic changes. Measures of voice quality deteriorated modestly following both exercises. By contrast, participant ratings of voice production were significantly improved after both tasks, more so with Acapella. The HR group reported significant reductions in tightness and aching following Acapella. Participants favored Acapella, finding it more practical and more likely to be used for daily practice.

Relationship between Apolipoproteins, Lipoprotein (a) and conventional cholesterol and lipids with insulin resistance.

Objective: To evaluate Apo-A1, Apo-B and Lipoprotein (a) and conventional lipid profile parameters among subjects with high and low insulin resistance groups. Study Design: Cross Sectional study. Setting: Naval Hospital, Islamabad. Period: 2018 to 2020. Material &amp; Methods: To include 164 subjects after several exclusions. We carried out conventional lipid indices along with serum insulin, Apo-A1, Apo-B and Lp (a) on these subjects after formal permission. We calculated insulin resistance by using the the HOMAIR index. Results: Male population demonstrated higher Apo-B [(Male: 66.44+21.75) vs (Female: 60.84+19.96), p=0.095], triglycerides [(Male: 2.29+1.35) vs (Female: 1.84+0.93), p=0.014] while male showed lower Lp (a) [(Male: 126.13+9.15) vs (Female:16.60+9.39), p=0.095] and Apo-A1. 126.13+21.97) vs (Female: 135.34 +25.24), p=0.017]. Apo-A1 showed highest but still weak positive correlation with HDLc, while Apo-B demonstrated higher positive correlation with total correlation, triglycerides, LDLc, non-HDLc and Lp (a). Among comparison between high and low insulin resistance groups, we could only demonstrate significant differences between triglycerides [Low insulin resistance group: 1.94+1.15 vs High insulin resistance group: 2.41+1.29, p=0.019] and Apo-A1 [Low insulin resistance group: 132.54+23.16 vs High insulin resistance group: 124.91+24.17, p=0.050]. Conclusion: Apo-B demonstrated higher positive correlation with total correlation, triglycerides, LDLc, non-HDLc and Lp (a). There were significant differences for triglycerides and Apo-A1 between insulin resistance groups. Female gender and higher insulin resistance groups demonstrated higher Apo-A1 levels.

Evaluation of oxidative/nitrative stress and uterine artery pulsatility index in early pregnancy.

Increased oxidative/nitrative stress is characteristic not only in pathologic, but also in healthy pregnancy. High uterine artery pulsatility index (UtAPI) at the end of the first trimester is associated with altered placentation and elevated risk for adverse pregnancy outcomes. We aimed to examine the relationship of systemic oxidative/nitrative stress and uterine artery pulsatility index in the first trimester and their correlation to pregnancy outcomes. Healthy pregnant women were recruited at 12-13th gestational week ultrasound examination; UtAPI was determined by color Doppler ultrasound. Patients were divided into high (UtAPI ≥ 2.3) (n = 30) and low (n = 31) resistance groups, and pregnancies were followed until labor. Systemic oxidative/nitrative stress was estimated by measuring total peroxide level, total antioxidant capacity and nitrotyrosine level. Plasma total peroxide level was significantly lower (2,510 ± 39 µM vs. 2,285 ± 59 µM), total antioxidant capacity was higher (781 ± 16 mM CRE vs. 822 ± 13 mM CRE) in the high UtAPI group, which were accompanied by lower birth weight (3,317 ± 64 vs. 3,517 ± 77 g, P < 0.05). Plasma total peroxide level showed a negative correlation (by Pearson) to UtAPI (P < 0.01) and positive correlation to birth weight (P < 0.05). According to our results, lower systemic oxidative stress showed correlation with high UtAPI measured between the 12-13th weeks of gestation. We also found significant differences in the birth weight of healthy newborns; therefore it is worth examining this relationship in pathological pregnancies.

Age-related myofiber atrophy in old mice is reversed by ten weeks voluntary high-resistance wheel running.

Age-related loss of muscle mass and function can be attenuated in rodents with life-long voluntary wheel running with moderate resistance. The present study assessed if sarcopenia could be counteracted with ten weeks high intensity training. Old (22-23months) and middle-aged (11months) mice were divided into three physical activity groups: Ten weeks of voluntary running in wheels with high (HR) or low resistance (LR), or no running wheel (SED). The wheel resistance was 0.5-1.5g in the LR group and progressed from 5g to 10g in the HR group. Six, 8 and 5 old and 8, 9 and 9 middle-aged mice of the SED, LR and HR groups, respectively, were included in the analysis. Wheel activity was monitored throughout the intervention. Muscle mass of the tibialis anterior, gastrocnemius, soleus and plantaris muscles were measured post-mortem. Fiber type distribution and myofiber cross sectional areal (CSA) were quantified in the gastrocnemius and soleus muscles as well as total number of fibers in the soleus muscle. In the SED, the mass of all individual muscles was reduced in the old vs middle-aged (P<0.001). In the training groups, the old mice ran significantly less, slower and for shorter bouts than the middle-aged throughout the intervention (P<0.05). HR running increased the gastrocnemius and soleus muscle mass by 6% and 18% respectively in the old compared to SED. Fiber CSA was significantly reduced in the old SED mice, whereas fiber CSA in the old HR gastrocnemius and soleus muscles was comparable to the SED middle-aged. Fiber type shifted from 2b towards 2a in the gastrocnemius muscle of the trained old mice. HR running was more efficient than LR in maintaining muscle mass and myofiber size, and in shifting fiber types. In the middle-aged mice, similar effects were found, but less pronounced. Interestingly, fiber CSA was unaffected by running in the middle-aged. Ten weeks of HR running had a positive effect on muscle mass and morphology in both middle-aged and old mice. The old HR fiber CSA was greater than in old SED and comparable to the middle-aged, and the fibers shifted to a more oxidative composition (2b→2a). Albeit less pronounced, similar training effects were observed in the middle-aged mice despite running faster and longer than the old.

Impact of nasal resistance on the distribution of apneas and hypopneas in obstructive sleep apnea

BackgroundThis study aims to investigate how increased nasal resistance affects respiratory variables in obstructive sleep apnea (OSA). In this setting, to assess how nasal resistance, as measured by 4-phase rhinomanometry, affects the distribution of hypopneas and apneas when measured with routine Sleep Polygraphy (PG). MethodsPG recordings were analysed and 4-phase rhinomanometry was conducted. Crude differences between groups were compared using Mann–Whitney Wilkoxon test. Odds for higher nasal resistance were modelled using logistic regression. All tests were two-sided. P < 0.05 was considered statistically significant. ResultsIn sum, 126 OSA patients referred to our center examined with PG were included. OSA Patients with a higher ratio of hypopneas relative to apneas are more than three times more likely (OR = 3.72, 95%CI [1.30–10.66], p = 0.015) to have increased nasal resistance as measured by 4-phase rhinomanometry, compared to those who have a lower ratio of hypopneas relative to apneas, regardless of OSA severity.The median Hypopnea to Apnea Ratio (HAR) in the low nasal resistance group was 0.8 compared to 2.6 in the high nasal resistance group (p = 0.000). The median apnea index in the low nasal resistance group was 13.6, in the high nasal group it was 5.2 (p = 0.001). ConclusionsOur investigation shows that OSA patients presenting with increased nasal resistance demonstrate significant differences in the distribution of hypopneas and apneas. OSA patients with increased nasal resistance exhibit a significantly lower apnea index and a higher hypopnea to apnea ratio compared to OSA patients presenting with low nasal resistance. Thus, analysis of the HAR in sleep studies is a useful tool to identify patients who may potentially have nasal obstruction as part of their respiratory pathophysiology. We therefore recommend that OSA patients with a predominance of hypopneas relative to apneas should undergo further nasal measurements.

Assessment of insulin sensitivity and resistance in non diabetic Punjabi population

Introduction: The pathogenesis of type 2 diabetes mellitus has been closely associated with dysfunctions observed in Insulin formation and pancreatic b cell functioning. Hepatic glucose output and insulin secretion from fasting levels of glucose and insulin have been widely validated clinically and epidemiologically to form a mathematical tool for estimating insulin resistance and b cell function. The tool has been named as the homeostasis Model Assessment tool (HOMA) and QUICK I index. The present study was designed to evaluate various biochemical parameters in two insulin resistance groups established by cutoffs of HOMA index and QUICK I. Materials and Methods: Total 5 00 non diabetic subjects attending the out-patient department of Sri Guru Ram Das Institute Of Medical Sciences and research Vallah, Sri Amritsar were included in the present study. After excluding 23 persons having HBA1C > 7 % we were left with 477 subjects. They were analyzed for Fasting Blood Glucose, HBA1C, S. Insulin and Lipid Profile. HOMA-IR index and QUICK I index were calculated using formulas. On the basis of the cutoffs of the above indices, the non diabetic persons were divided into High and Low insulin resistance groups. Results: Prevalence of insulin resistance in non diabetic general population was 41.5 % as estimated by cutoffs established by QUICK I index. It was much lower when HOMA IR index was used. Conclusion: Quick I is the more sensitive index as compared to HOMA IR for the screening of Insulin resistance. Moreover, the amount of adipose tissue is the risk factor for Insulin resistance and not the sex. Keywords: Insulin Resistance, QUICK I, Modified QUICK I, HOMA Ir.

Clinical phenotyping of newly diagnosed type 2 diabetes in Yemen

ObjectiveTo identify clinical phenotypes of type 2 diabetes (T2D) among adults presenting with a first diagnosis of diabetes.Research design and methodsA total of 500 consecutive patients were subject to clinical...

Relationship of insulin resistance with serum 25-hydroxyvitamin D levels and arterial stiffness in elderly patients

Objective To explore the relationship of insulin resistance with serum 25-hydroxyvitamin D levels and arterial stiffness in elderly patients. Methods A total of 162 elderly inpatients (aged 60 years or over) were recruited from 2012 to 2014. Levels of fasting serum insulin, fasting serum glucose, creatinine and vitamin D were determined. Insulin resistance (IR) was evaluated by the homeostasis model assessment of insulin resistance (HOMA-IR). The patients were divided into the following three groups according to HOMA-IR: the low IR group with HOMA-IR less than 2 (n=78), the median IR group with HOMA-IR between 2 and 6 (n=43), and the high IR group with HOMA-IR greater than 6 (n=41). Arterial stiffness was assessed by carotid-femoral pulse wave velocity (cfPWV). Arterial stiffness and serum vitamin D levels were compared among the three groups. Results cfPWV was increased and the serum 25-hydroxyvitamin D level was decreased in the high insulin resistance group compared with the low insulin resistance group〔(13.2±5.7) μg/L vs. (17.8±6.2) μg/L, (14.3±5.2) m/s vs. (11.9±3.0) m/s〕. Multiple liner regression analysis showed that IR was negatively correlated with the serum 25-hydroxyvitamin D level (r=-0.63, P<0.05) and positively correlated with arterial stiffness (r=0.45, P<0.05) after adjustment for age, sex and other confounders. Conclusions Elderly patients with high insulin resistance may have lower levels of serum vitamin D and higher arterial stiffness. Key words: Insulin resistance; Vitamin D deficiency; Arteriosclerosis

不同品种小麦叶片对拔节期低温的生理响应及抗寒性评价

Cold injury is one of the main problems in winter wheat production in the Huanghuaihai wheat region.Winter wheat grows rapidly at the jointing stage,and becomes sensitive to the drops in temperatures that frequently occur in spring.Low temperature during the jointing stage restricts the growth of winter wheat and directly affects grain yield.Therefore,correctly evaluating and improving the cold resistance of wheat varieties is very important for grain security.In this study,we evaluated the cold tolerance of 24 wheat varieties grown in the Huanghuaihai region.The wheat plants were grown in pots outdoors,and they were moved into an artificial climate chamber and subjected to a cold treatment at the jointing stage.After the cold treatment,we measured seven physiological indices in leaves; relative electrical conductivity,soluble sugars content,soluble protein content,free proline content,malondialdehyde( MDA) content,superoxide dismutase( SOD)activity,and peroxidase( POD) activity.The results showed that the soluble protein content was lower in low-temperaturetreated plants than in the control plants( P0.01),while the other six indices showed higher values in the low-temperature-treated plants than in the control plants( P0.01).Analysis of variance showed that the values of these seven physiological indices differed significantly among varieties both in low-temperature-treated and control plants( P0.01).Compared with control plants,the low-temperature-treated plants showed a greater range of relative conductivity,soluble sugars content,soluble proline content,MDA content,and POD activity,but lower range of soluble protein content and SOD activity.The relative character value,that is,the proportion of the measured value in low-temperature-treated plants to that in control plants,eliminated the genetic background difference.For each wheat variety,we used the relative character values to calculate the average subordinative function value by the subordinative function method,and we calculated the comprehensive score by the polar ordination method.The average subordinative function values ranged from 0.19 to 0.63 and the comprehensive scores from 1.66 to 4.08.Among the 24 cultivars,Liangxing 619 showed the highest value and score,while Shiyou 20 showed the lowest.Using K-means clustering analysis,the 24 winter wheat cultivars were divided into five groups according to cold resistance; strong,high,medium,low,and weak.The strong cold resistance group contained six varieties; Lingxing 619,Fengdecunmai No.1,B07-4056,Shi H083-363,Shannong 055843,and Lingxing 99.The high cold resistance group contained seven varieties; Su 553,Shannong 509,A-9,Zhongyuan No.6,Xumai 4036,Shunmai1718,and Shimai 19.The medium cold resistance group consisted of five varieties; Yaomai 16,C-44,Shannong 05-066,Jimai 585,and Shi B05-7388.The low cold resistance group contained Yanzhan 4110,B-33,B05-6507,and Shi 4185.Two varieties,Shiyou 20 and Shi 06-6136,were in the weak cold resistance group.Correlation analyses showed that the average subordinative function value and comprehensive score were significantly positively correlated with soluble sugars content and relative proline content( P 0.01),and with relative POD activity( P 0.05).The average subordinative function value and comprehensive score were significantly negatively correlated with relative MDA content( P 0.05).In conclusion,the soluble sugars content,free proline content,POD activity,and MDA content in leaves at the jointing stage can serve as cold-resistance indices.Wheat varieties with higher soluble sugars content,free proline content,and POD activity,but lower MDA content in leaves showed stronger cold resistance.Among the 24 varieties,Liangxing 619 showed the strongest cold resistance at the jointing stage,while Shiyou 20 showed the weakest.

Accuracy of Doppler-Derived Indices in Predicting Pulmonary Vascular Resistance in Children With Pulmonary Hypertension Secondary to Congenital Heart Disease With Left-to-Right Shunting

This study aimed to evaluate the accuracy of Doppler echocardiography-derived indices in children with pulmonary hypertension secondary to congenital heart disease with left-to-right shunting. Doppler-derived indices including the acceleration time corrected (AcTc), deceleration time corrected, deceleration index, peak velocity, heart-rate-corrected inflection time (InTc), and a new index (the acceleration slope [Acc = peak flow velocity/AcTc]) were measured from the pulmonary artery (PA) systolic flow curve before and after 100 % oxygen administration in the main, left, and right PAs of 33 children. The acquired data were compared between low and high pulmonary vascular resistance (PVR) groups and between responders and nonresponders to the vasoreactivity test. The AcTc values differed significantly between the low and high PVR groups before and after oxygen administration in the main (P = 0.032 and <0.001, respectively), right (P = 0.011 and <0.001, respectively), and left (P < 0.001 and <0.001, respectively) PAs. The AcTc cutoff point in the main PA was 3.44 before oxygen administration (81% sensitivity and 91% specificity). The InTc in the main PA and its changes differed significantly between the low and high PVR groups before and after oxygen administration and between the responders and nonresponders (P = 0.016, 0.046, and 0.021, respectively). The velocity changes of the PA in the main PA differed significantly between the responders and nonresponders to oxygen administration (P < 0.001). The Acc and its changes differed significantly between the low and high PVR groups after oxygen administration and between the responders and nonresponders to oxygen administration (P = 0.044 and 0.006, respectively). Doppler echocardiographic examination using PA systolic flow indices in addition to PA reactivity testing is a promising technique for assessing PVR in children with congenital heart disease.

HSP90 expression correlation with the freezing resistance of bull sperm

To date, there has been little improvement in cryopreservation of bull sperm due to lack of understanding of the freezing mechanisms. Therefore, this study set out to investigate expression levels of fertility-associated proteins in bull sperm, and in particular the relationship between the 90 kDa heat-shock protein (HSP90) and the sperm characteristics after freezing-thawing. Semen was collected from eight Holstein bulls by artificial vagina. Characteristics of these fresh semen, including sperm motility, morphology, viability and concentration, were evaluated. Sperm quality was also assessed after freezing-thawing. Eight ejaculates were divided into two groups based on freezing resistance and sperm motility. Sperm proteins were extracted and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) analysis and western blotting were performed. SDS-PAGE results showed that there was substantial diversity in 90 kDa proteins in the frozen-thawed sperm and HSP90 was confirmed as one of the 90 kDa proteins by western blot. This study indicated that HSP90 expression correlated positively with sperm quality. The amount of expressed 90 kDa proteins in the high freezing resistance (HFR) group was significantly higher than that in the low freezing resistance (LFR) group (P < 0.05). Thus, higher expression of HSP90 could probably lead to the higher motility and freezing resistance of sperm found after freezing-thawing. Therefore, we concluded that level of HSP90 expression could be used to predict reliably and simply the freezing resistance of bull sperm.

Analysis of the relationship between the MecA gene and resistance of β-lactam antibiotics

To investigate the mechanisms by which MecA gene expression leads to β-lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA), and to study the resistance mechanism of MRSA at the molecular level. A variety of molecular biological techniques were employed, including screening MRSA using cefoxitin paper disk method, extraction of MRSA mRNA, reverse transcription into cDNA, real-time fluorescence PCR for quantitation of MecA gene expression, and agar dilution method for assessment of minimum inhibitory concentrations in MRSA treated with cefoxitin, oxacillin, vancomycin, or linezolid. According to the level of resistance of MRSA to cefoxitin, 40 MRSA strains were divided into a low resistance group (n=12), a middle resistance group (n=15), and a high resistance group (n=13). The expression level of the MecA gene in the low resistance group, the middle resistance group, and the high resistance group was 58.87±30.30, 363.37±200.05, and 1257.72±446.63, respectively. MRSA resistance to cefoxitin and oxacillin was 100%; MRSA resistance to vancomycin or linezolid could not be detected. For all 40 MRSA strains the MIC90 for vancomycin was 2.0 μg/mL. MecA gene expression levels may correlate with the MRSA level of resistance to cefoxitin within a certain range of concentration.

The regulatory-adaptive state and evaluation of stress resistance in humans

The method of estimating human stress resistance by the dynamics of the regulatory-adaptive state is described. The regulatory-adaptive state has been evaluated by the parameters of cardio-respiratory synchronism in the normal state and in stress. Subjects with no changes in the regulatory-adaptive state or with its decrease by 5–6% have been included in the group with a high level of stress resistance. Subjects with a decrease of the regulatory-adaptive state by more than 50% in response to stress have been included in the low stress resistance group. The method has been tested in three models of stress: (1) examination (58 students); (2) parachute jumping (35 beginner parachute jumpers); (3) entrance to an emergency zone (30 rescuers). All three models are highly informative. Stress resistance levels have also been estimated by psycho-logical methods. The estimation of stress resistance by the dynamics of the regulatory-adaptive state allows characterizing the ability of a person to endure stress and can be included in the set of tests for staff recruitment in extreme professions.

High early uterine vascular resistance values increase the risk of adverse pregnancy outcome independently from placental VEGF and VEGFR1 reactivities

Objective From data in the literature, we hypothesized that high vascular resistance values in the uterine arteries at the end of the first trimester would increase adverse pregnancy outcomes and therefore might be accompanied by changes in VEGF/VEGFR1 immunoreactivities. Study design In our university hospital 82 women (Study I n = 62 and Study II n = 20) were divided into two groups according to their uterine vascular resistance values. Uterine vascular resistance values were measured in the 10–13th weeks of gestation by color-Doppler ultrasonography. Women were divided into low and high vascular resistance groups. In the prospective follow-up study (Study I) the data of the pregnancy outcome were recorded. In cross-sectional study (Study II), VEGF and VEGFR1 immunoreactivities were measured on the tissue samples from women who underwent termination of pregnancy. Results In the high vascular resistance group (PI > 2.3), the probability of adverse pregnancy outcome was significantly higher (40.0% vs. 12.8%). No differences in VEGF and VEGFR1 immunoreactivities were observed between groups. In both groups, intense VEGF immunoreactivity was observed in the maternal glandular epithelium and in the decidual cells. Weak reactivity was observed in the villous trophoblast. VEGFR1 immunoreactivity was intense in all regions. Conclusions Our data suggest that high vascular resistance values in the first trimester are independent from VEGF/VEGFR1 immunoreactivities and markedly increase the probability of adverse pregnancy outcomes. This may be used for early screening of pregnant women in the first trimester.

Collateral Ventilation to Congenital Hyperlucent Lung Lesions Assessed on Xenon-Enhanced Dynamic Dual-Energy CT: an Initial Experience

ObjectiveWe wanted to evaluate the resistance to collateral ventilation in congenital hyperlucent lung lesions and to correlate that with the anatomic findings on xenon-enhanced dynamic dual-energy CT.Materials and MethodsXenon-enhanced dynamic dual-energy CT was successfully and safely performed in eight children (median age: 5.5 years, 4 boys and 4 girls) with congenital hyperlucent lung lesions. Functional assessment of the lung lesions on the xenon map was done, including performing a time-xenon value curve analysis and assessing the amplitude of xenon enhancement (A) value, the rate of xenon enhancement (K) value and the time of arrival value. Based on the A value, the lung lesions were categorized into high or low (A value > 10 Hounsfield unit [HU]) resistance to collateral ventilation. In addition, the morphologic CT findings of the lung lesions, including cyst, mucocele and an accessory or incomplete fissure, were assessed on the weighted-average CT images. The xenon-enhanced CT radiation dose was estimated.ResultsFive of the eight lung lesions were categorized into the high resistance group and three lesions were categorized into the low resistance group. The A and K values in the normal lung were higher than those in the low resistance group. The time of arrival values were delayed in the low resistance group. Cysts were identified in five lesions, mucocele in four, accessory fissure in three and incomplete fissure in two. Either cyst or an accessory fissure was seen in four of the five lesions showing high resistance to collateral ventilation. The xenon-enhanced CT radiation dose was 2.3 ± 0.6 mSv.ConclusionXenon-enhanced dynamic dual-energy CT can help visualize and quantitate various degrees of collateral ventilation to congenital hyperlucent lung lesions in addition to assessing the anatomic details of the lung.