Changes of the peripapillary vascular parameters inpremature infants without retinopathy of prematurityusing U-net segmentation

AIM:To quantitatively assess the changes in mean vascular tortuosity(mVT)and mean vascular width(mVW)around the optic disc and their correlation with gestational age(GA)and birth weight(BW)in premature infants without retinopathy of prematurity(ROP).METHODS:A single-center retrospective study included a total of 133(133 eyes)premature infants[mean corrected gestational age(CGA)43.6wk]without ROP as the premature group and 130(130 eyes)CGA-matched fullterm infants as the control group.The peripapillary mVT and mVW were quantitatively measured using computerassisted techniques.RESULTS:Premature infants had significantly higher mVT(P=0.0032)and lower mVW(P=0.0086)by 2.68(10^(4) cm^(-3))and 1.85μm,respectively.Subgroup analysis with GA showed significant differences(P=0.0244)in mVT between the early preterm and middle to late preterm groups,but the differences between mVW were not significant(P=0.6652).The results of the multiple linear regression model showed a significant negative correlation between GA and BW with mVT after adjusting sex and CGA(P=0.0211 and P=0.0006,respectively).For each day increase in GA at birth,mVT decreased by 0.1281(10^(4) cm^(-3))and for each 1 g increase in BW,mVT decreased by 0.006(10^(4) cm^(-3)).However,GA(P=0.9402)and BW(P=0.7275)were not significantly correlated with mVW.CONCLUSION:Preterm birth significantly affects the peripapillary vascular parameters that indicate higher mVT and narrower mVW in premature infants without ROP.Alterations in these parameters may provide new insights into the pathogenesis of ocular vascular disease.

Rice melatonin deficiency causes premature leaf senescence via DNA methylation regulation

In a study of DNA methylation changes in melatonin-deficient rice mutants,mutant plants showed premature leaf senescence during grain-filling and reduced grain yield.Melatonin deficiency led to transcriptional reprogramming,especially of genes involved in chlorophyll and carbon metabolism,redox regulation,and transcriptional regulation,during dark-induced leaf senescence.Hypomethylation of mCG and mCHG in the melatonin-deficient rice mutants was associated with the expression change of both protein-coding genes and transposable element-related genes.Changes in gene expression and DNA methylation in the melatonin-deficient mutants were compensated by exogenous application of melatonin.A decreased S-adenosyl-L-methionine level may have contributed to the DNA methylation variations in rice mutants of melatonin deficiency under dark conditions.

Being a Father of a Premature Newborn: The Parental Experience and the Father/Premature Newborn Relationship: A Study Carried out in the Department of Neonatology Intensive Care Unit of Mohammed VI University Hospital

Introduction: Despite advances in obstetrics and pediatrics over the past 20 years, premature birth remains an unpredictable event that can have a devastating impact on parenthood. This study aimed to analyze the psycho-affective experiences of fathers of premature newborns. Methods: This was a descriptive cross-sectional study, carried out in the department of neonatology and neonatal intensive care unit of the CHU Mohamed VI in OUJDA, over 6 months from March 2022 to August 2022. It focused on 30 fathers of premature newborns hospitalized in our department. Results: The majority of fathers described a state of fear and stress, and attributed their negative experience to the unexpected nature of the premature birth. At the first meeting, half the fathers had a positive image of their newborn’s physical appearance, while 22% of fathers reported feeling uncomfortable about their newborn’s low weight. Most fathers reported that they appreciated the welcome they received, the skill with which they cared for their newborn, and the availability of the pediatrician to provide information on their child’s state of health. Two fathers enjoyed skin-to-skin contact with their newborns. None of the fathers met a psychologist. When they returned home, half the fathers had a positive outlook, marked by happiness at being able to fully invest in their role as fathers, the other half reported being torn between the desire to see their child integrated into the family cocoon and the fear of not being able to manage delicate situations properly without a medical team. Conclusion: Bringing a premature baby into the world can be a difficult experience, leading to the development of even minor psychological distress in some fathers, and hence the need for specific psychological care.

Current Status of Stem Cells in the Treatment of Premature Ovarian Failure

Premature ovarian failure (POF) is a prevalent cause of female infertility. POF features include estrogen hypofunction, amenorrhea, infertility, and high gonadotropin levels. The etiology of POF is genetic diseases, autoimmune diseases, enzyme defects and environmental factors. The development of Regenerative medicine has made stem cell and exosome (EXOs) therapy effective for POF. This review discusses POF stem cell research and development.

Application of mesenchymal stem cell therapy for premature ovarian insufficiency: Recent advances from mechanisms to therapeutics

The incidence of premature ovarian insufficiency(POI)is increasing worldwide,particularly among younger women,posing a significant challenge to fertility.In addition to menopausal symptoms,POI leads to several complications that profoundly affect female reproductive function and overall health.Unfortunately,current clinical treatment strategies for this condition are limited and often yield unsatisfactory outcomes.These approaches typically involve hormone repla-cement therapy combined with psychological support.Recently,mesenchymal stem cell(MSC)therapies for POI have garnered considerable attention in global research.MSCs can restore ovarian reproductive and endocrine functions through diverse mechanisms,including controlling differentiation,promoting angiogenesis,regulating ovarian fibrosis,inhibiting apoptosis,enhancing autocrine and paracrine effects,suppressing inflammation,modulating the immune system,and genetic regulation.This editorial offers a succinct summary of the application of MSC therapy in the context of POI,providing evidence for groundbreaking medical approaches that have potential to enhance reproductive health and overall well-being for women.

Exploration of standard dosage for GnRH antagonist protocol and dosage adjustments after premature luteinizing hormone surge

The gonadotropin-releasing hormone (GnRH) antagonist protocol has emerged as an efficacious alternative to the GnRH agonist protocol for controlled ovarian hyperstimulation (COH) during in vitro fertilization (IVF) cycles, and has been demonstrated applicability in infertile female patients with diverse ovarian responses. While the clinical implementation of the antagonist COH protocol has achieved widespread consensus, opportunities for refinement persist. Therefore, this review article focuses on the advantages and disadvantages of GnRH antagonist protocol, the selection of optimal standard doses, and the strategies for adjusting antagonist doses after the premature luteinizing hormone (LH) surge, aiming to provide more reasonable and scientific recommendations for the application of this scheme.

Significance of oxidative stress and antioxidant capacity tests as biomarkers of premature ovarian insufficiency: A case control study

BACKGROUND Premature ovarian insufficiency(POI)is a condition that causes secondary amenorrhea owing to ovarian hypofunction at an early stage.Early follicular depletion results in intractable infertility,thereby considerably reducing the quality of life of females.Given the continuum in weakened ovarian function,progressing from incipient ovarian failure(IOF)to transitional ovarian failure and further to POI,it is necessary to develop biomarkers for predicting POI.The oxidative stress states in IOF and POI were comprehensively evaluated via oxidative stress[diacron-reactive oxygen metabolites(d-ROMs)]test and anti-oxidant capacity[biological antioxidant potential(BAP)].METHODS Females presenting with secondary amenorrhea over 4 mo and a follicle stimulating hormone level of>40 mIU/mL were categorized into the POI group.Females presenting with a normal menstrual cycle and a follicle stimulating hormone level of>10.2 mIU/mL were categorized into the IOF group.Healthy females without ovarian hypofunction were categorized into the control group.Among females aged<40 years who visited our hospital from January 2021 to June 2022,we recruited 11 patients into both POI and IOF groups.For the potential antioxidant capacity,the relative oxidative stress index(BAP/d-ROMs×100)was calculated,and the oxidative stress defense system was comprehensively evaluated.RESULTS d-ROMs were significantly higher in the POI and IOF groups than in the control group,(478.2±58.7 U.CARR,434.5±60.6 U.CARR,and 341.1±35.1 U.CARR,respectively)(U.CARR is equivalent to 0.08 mg/dL of hydrogen peroxide).However,no significant difference was found between the POI and IOF groups.Regarding BAP,no significant difference was found between the control,IOF,and POI groups(2078.5±157.4μmol/L,2116.2±240.2μmol/L,and 2029.0±186.4μmol/L,respectively).The oxidative stress index was significantly higher in the POI and IOF groups than in the control group(23.7±3.3,20.7±3.6,and 16.5±2.1,respectively).However,no significant difference was found between the POI and IOF groups.CONCLUSION High levels of oxidative stress suggest that evaluating the oxidative stress state may be a useful indicator for the early detection of POI.

Acquired methemoglobinemia in a third trimester puerpera and her premature infant with sodium nitrite poisoning:A case report

BACKGROUND The common cause of sodium nitrite poisoning has shifted from previous accidental intoxication by exposure or ingestion of contaminated water and food to recent alarming intentional intoxication as an employed method of suicide/exit.The subsequent formation of methemoglobin(MetHb)restricts oxygen transport and utilization in the body,resulting in functional hypoxia at the tissue level.In clinical practice,a mismatch of cyanotic appearance and oxygen partial pressure usually contributes to the identification of methemoglobinemia.Prompt recognition of characteristic mismatch and accurate diagnosis of sodium nitrite poisoning are prerequisites for the implementation of standardized systemic interventions.CASE SUMMARY A pregnant woman was admitted to the Department of Critical Care Medicine at the First Affiliated Hospital of Harbin Medical University due to consciousness disorders and drowsiness 2 h before admission.Subsequently,she developed vomiting and cyanotic skin.The woman underwent orotracheal intubation,invasive mechanical ventilation(IMV),and correction of internal environment disturbance in the ICU.Her premature infant was born with a higher-than-normal MetHb level of 3.3%,and received detoxification with methylene blue and vitamin C,supplemental vitamin K1,an infusion of fresh frozen plasma,as well as respiratory support via orotracheal intubation and IMV.On day 3 after admission,the puerpera regained consciousness,evacuated the IMV,and resumed enteral nutrition.She was then transferred to the maternity ward 24 h later.On day 7 after admission,the woman recovered and was discharged without any sequelae.CONCLUSION MetHb can cross through the placental barrier.Level of MetHb both reflects severity of the sodium nitrite poisoning and serves as feedback on therapeutic effectiveness.

Recent Research Progress in Premature Ovarian Failure

Premature ovarian failure refers to ovarian function failure in women before the age of 40 years due to follicular depletion or follicular dysfunction resulting in abnormal hormone levels.The etiology and pathogenesis of premature ovarian failure may be related to genetic,immunological,medical,environmental,infectious,psychological and enzyme deficiencies.The treatment involves Western medicine,Chinese medicine,and a combination of Chinese and Western medicine,and the treatment level includes hormone level,cellular level,surgery and psychological aspect.This paper would like to review the progress of the etiology,pathogenesis and treatment of premature ovarian failure in recent years.

Research Progress on the Prevention of Premature Infant Lung Injury and Neonatal Respiratory Support

In the past 40 years,advances in neonatal intensive care unit(NICU)technology have enabled premature infants with lower birth weight and younger gestational age to survive.But with it comes an increase in the incidence of long-term respiratory dysfunction,mainly in the form of bronchopulmonary dysplasia(BPD).Preventing lung injury is crucial for preventing BPD and improving the long-term prognosis of premature infants.Therefore,how to avoid ventilator-associated lung injury has become a focus of clinical and scientific research in premature infants in recent years.This article will elaborate on the susceptibility and pathophysiology of premature infant lung injury,ventilation strategies for preventing lung injury,and new advances in neonatal respiratory support.

Analysis of oxidative stress and antioxidative potential in premature ovarian insufficiency

BACKGROUND Premature ovarian insufficiency(POI)is characterized by an early decline in ovarian function,inducing secondary amenorrhea.While the cause of POI has not yet been identified,the function of mitochondria in the ovaries and the cytotoxicity associated with reactive oxygen species(ROS)have been implicated in follicle pool depletion and a decline in follicle quality.Recently developed tests have enabled easy measurement of diacron-reactive oxygen metabolites(d-ROMs)and biological antioxidant potential(BAP).The combination of these two tests is used to comprehensively assess oxidative stress in the blood.AIM To comprehensively assess the oxidative stress of d-ROMs and BAP in POI.METHODS Participants were classified into two groups:A POI group of 11 women aged<40 years examined between January 2021 and June 2022 with a history of secondary amenorrhea for at least 4 mo in our hospital and an FSH value of≥40 mIU/mL;and a control group of healthy women of the same age with normal ovarian function in our hospital.Plasma d-ROMs and BAP were measured in both these groups underwent.Differences between groups were assessed using the t-test.RESULTS The mean age and mean body mass index(BMI)were 35.8±3.0 years and 20.1±1.9 kg/m2 in the control group and 35.8±2.7 years and 19.4±2.5 kg/m2 in the POI group,respectively.The mean gravidity and parity in control and POI groups were 0.6±0.7 and 0.4±0.5 and 0.6±0.9 and 0.3±0.5,respectively.The two groups did not differ significantly in terms of mean age,BMI,gravidity,or parity.The d-ROMs level was significantly higher in the POI group than in the control group(478.2±58.7 vs 341.1±35.1 U.CARR;P<0.001);however,the BAP level did not significantly differ between the two groups(2078.5±157.4 vs 2029.0±186.4μmol/L).The oxidase stress index(d-ROMs/BAP×100)was significantly higher in the POI group than in the control group(23.7±3.3 vs 16.5±2.1;P<0.001).CONCLUSION Oxidative stress was significantly greater in the POI group than in the control group,suggesting oxidative stress as a factor that can serve as a POI biomarker.

Lamellar Bodies Count (LBC) as a Predictor of Fetal Lung Maturity in Preterm Premature Rupture of Membranes Compared to Neonatal Assessment

Background: Respiratory distress syndrome (RDS) is a major cause of neonatal morbidity and mortality, affecting approximately 1% of all live births and 10% of all preterm infants. Lamellar bodies represent a storage form of pulmonary surfactant within Type II pneumocytes, secretion of which increases with advancing gestational age, thus enabling prediction of the degree of FLM. Preterm premature rupture of membranes (PPROM) complicates approximately 1/3 of all preterm births. Birth within 1 week is the most likely outcome for any patient with PPROM in the absence of adjunctive treatments. Respiratory distress has been reported to be the most common complication of preterm birth. Sepsis, intraventricular haemorrhage, and necrotizing enterocolitis also are associated with prematurity, but these are less common near to term. Objective: To assess the efficacy of the amniotic fluid lamellar body counting from a vaginal pool in predicting fetal lung maturity in women with preterm premature rupture of membranes. Methods: This study was conducted at Ain Shams University Maternity Hospital in the emergency ward from January 2019 to September 2019. It included 106 women with singleton pregnancies, gestational age from 28 - 36 weeks with preterm premature rupture of membranes. This study is designed to assess the efficacy of the amniotic fluid lamellar body counting (LBC) from a vaginal pool in predicting fetal lung maturity in women with preterm premature rupture of membranes. Results: The current study revealed a highly significant increase in the lamellar body count in cases giving birth to neonates without RDS compared to that cases giving birth to neonates with RDS. Also, no statistically significant difference between LBC and age, parity and number of previous miscarriages in the mother was found. Gestational age at delivery was significantly lower among cases with respiratory distress. Steroid administration was significantly less frequent among cases with respiratory distress. However, lamellar bodies had high diagnostic performance in the prediction of respiratory distress. Conclusion: Lamellar body count (LBC) is an effective, safe, easy, and cost-effective method to assess fetal lung maturity (FLM). It does not need a highly equipped laboratory or specially trained personnel, it just needs the conventional blood count analyzer. Measurement of LBC is now replacing the conventional Lecithin/Sphyngomyelin L/S ratio. LBC cut-off value of ≤42.5 × 103/μL can be used safely to decide fetal lung maturity with sensitivity of 95.7% and specificity of 97.6%.

Intermittent spontaneous ovulation in patients with premature ovarian failure:Three case reports and review of literature

BACKGROUND Premature ovarian failure(POF)is the end-stage of a decline in ovarian function prior to the age of 40 years that involves symptoms associated with low estradiol(E2)levels and a minimal probability of pregnancy.This increases the physical and psychological burden experienced by young women of reproductive age,particularly with regards to over-diagnosis.CASE SUMMARY Here,we report three cases(29,22,and 33 years-of-age)diagnosed with POF after experiencing secondary amenorrhea for more than one year,serum levels of follicle-stimulating hormone(FSH)>40 IU/L on two occasions with an interval of more than 4 wk,and negative progesterone withdrawal tests.All three patients were intermittently administered with drugs to create an artificial cycle.During the subsequent discontinuation period,the patients experienced intermittent follicular growth and spontaneous ovulation.One patient experienced two natural pregnancies(both with embryo arrest).CONCLUSION Our findings suggest that young patients with POF can experience unpredictable and intermittent spontaneous follicular development,ovulation,and even natural pregnancy.Clinicians should provide appropriate medical guidance and individualized treatments according to fertility requirements,genetic risks and hypoestrogenic symptoms as soon as possible.

Previable Premature Rupture of Membranes in Dichorionic Diamniotic Twin Gestation, Loss of Leading Twin, Emergency Cervical Cerclage and Ceaserean Delivery at Term

Introduction: Multiple pregnancies have a higher risk of premature delivery and a weakened cervix has been associated with it. In most cases, emergency cerclage has proved to be beneficial as the birth of the first twin is usually followed by the unavoidable delivery of the second twin and most fetus dies shortly after delivery. Studies have noted that delayed delivery of the second fetus in a twin pregnancy is an effective management choice and the use of cervical cerclage after the first delivery is associated with a longer inter-delivery interval. We present a case of previable premature rupture of membrane of a dichorionic diamniotic twin gestation leading to the loss of the leading twin and subsequently having emergency cervical cerclage for the second twin and caesarean delivery at term. Case Presentation: She was a case of a 29 years old, G6P1+4 with 1 living child at a gestational age of 17 weeks plus 5 days who initially was diagnosed with dichorionic diamniotic twin gestation following an early ultrasound but presented with a history of bleeding and passage of liquor per vaginam. Ultrasound done on admission showed cervical funneling and a stable state of the second twin. She subsequently had emergency cervical cerclage after stabilization on account of previable premature rupture of membrane of a dichorionic diamniotic twin gestation with the loss of the leading twin. A repeat ultrasound done prior to discharge showed closed cervical os and a good state of the fetus. She then had elective caesarean delivery at term with a good feto-maternal outcome. Conclusion: Emergency cervical cerclage should be part of the options of management after stabilization in cases of previable premature rupture of membrane in a dichorionic or multichoronic gestation so as to save the viable once.

Co-Morbidities Associated with Prematurity in Two Referral Hospitals in Cameroon

Introduction: Prematurity is the leading cause of neonatal death in Africa. More than a million children die each year due to co-morbidities related to prematurity. In addition to being one of the causes of neonatal deaths, the health problems associated with prematurity can also lead to severe lifelong impairment in those who survive. Objectives: This paper aims to determine the epidemiology and identify co-morbidities of prematurity in the neonatology units of the Douala General Hospital (DGH) and the Laquintinie Hospital of Douala (LHD). Patients and Methodology: We conducted an analytical retrospective cohort study from January 2015 to January 2018 in the neonatology department of the GDH and the LHD, which are considered reference hospitals for the management of preterm babies in Cameroon. We included all newborns aged less than 37 weeks admitted to the neonatology units of the GDH and the LHD. The descriptive component was based on the analysis of quantitative variables using measures of central tendency. The analytical component was evaluated using Spearman correlations and the Chi-square and Fisher tests. Simple and multiple logistic regressions measured factors predictive of mortality. The Kaplan Meier survival curve used the Log Rank test and significance at p ≤ 0.05. Results: We recorded 908 preterm newborns in neonatal service and 1,124 preterm deliveries in maternity, representing an incidence of 32.5% in neonatal unit and 10.6% in maternity. 51% of whom were girls, given a sex ratio M/F of 0.9. Hypertension was the main prenatal pathology (9.1%), while premature rupture of membranes: PROM (35.5%) and eclampsia/pre-eclampsia (18.6%) were the most common obstetrical pathologies. 75.9% of deliveries were vaginal with 65.2% being performed in our referral hospitals. Gestational age ranged from 22 to 36 weeks, with a mean of 32.4 weeks. Late preterm birth rate was 53.7%, and birth weight varied between 590 and 3200 g with an average of 1747 ± 479 g. The percentage of low birth weight (1500 - 2499 g) preterm infants was predominant (65.3%), and the intrauterine growth restriction (IUGR) was estimated to be 12.4%. The majority (96.7%) had pathologies in the neonatal period, the most common being neonatal infection (86.9%). The case-fatality rate was 27.4%, compared to 72.6% live births. Factors influencing mortality are risk of premature labour, gestational age ≤ 32 SA, premature birth in hospitals other than our two referral hospitals, birth weight ≤ 1500 g, Apgar at the 10th minute, late secondary anaemia, hospital resuscitation, oxygen therapy, and duration of hospitalization Conclusion: The incidence of prematurity and the mortality rate remains high in neonatal units in Cameroon. Adequate monitoring of pregnancies and management of preterm infants remains a challenge in our context.

Predictors and Complications of Prematurity in Two Health Facilities in Fako Division, Southwest Region, Cameroon

Background: Prematurity is the leading cause of neonatal mortality. Most preterm births can be associated to an identifiable risk factor. In Cameroon, especially in the Southwest Region, there is limited data regarding prematurity associated risk factors. The aim of this study was to evaluate the risk factors and complications of prematurity in two health facilities in the Fako division, the BRH and RHL. Methods: A hospital based retrospective case control study was done from the 1st of January 2021 to 28th of February 2022. We assessed the gestational ages at which preterm birth occurred and their short-term outcome using a structured pretested questionnaire to collect data from files. Data was analyzed using Statistical Package for Social Sciences (SPSS) version 26. Results: The minimum sample size was 137 preterms. 45.5% of cases were born between 34 and increased the risk of having a preterm birth meanwhile being married (AOR: 0.410;95% CI: 0.217 - 0.773;p = 0.006) decreased the risk. Hospital complications were neonatal infection 103 (51.5%), respiratory distress 79 (39.5%) and neonatal jaundice 61 (30.50%). Among the cases, 97 (48.50%) stayed in the hospital for 2 to 4 weeks and 177 (88.5%) were discharged alive. Conclusions: Modifiable factors that increased the risk of prematurity were advanced maternal age, secondary level of education, rural residence, and prenatal alcohol consumption. Being married decreased the risk. The most common hospital complications in both the cases and controls were neonatal infection, respiratory distress syndrome and neonatal jaundice.

Nomogram to predict severe retinopathy of prematurity in Southeast China

AIM:To define the predictive factors of severe retinopathy of prematurity(ROP)and develop a nomogram for predicting severe ROP in southeast China.METHODS:Totally 554 infants diagnosed with ROP hospitalized in the Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University and hospitalized in Taizhou Women and Children’s Hospital were included.Clinical data and 43 candidate predictive factors of ROP infants were collected retrospectively.Logistic regression model was used to identify predictive factors of severe ROP and to propose a nomogram for individual risk prediction,which was compared with WINROP model and Digirop-Birth model.RESULTS:Infants from the Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University(n=478)were randomly allocated into training(n=402)and internal validation group(n=76).Infants from Taizhou Women and Children’s Hospital were set as external validation group(n=76).Severe ROP were found in 52 of 402 infants,12 of 76 infants,and 7 of 76 infants in training group,internal validation group,and external validation group,respectively.Birth weight[odds ratio(OR),0.997;95%confidence interval(CI),0.996-0.999;P<0.001],multiple births(OR,1.885;95%CI,1.013-3.506;P=0.045),and non-invasive ventilation(OR,0.288;95%CI,0.146-0.570;P<0.001)were identified as predictive factors for the prediction of severe ROP,by univariate analysis and multivariate analysis.For predicting severe ROP based on the internal validation group,the areas under receiver operating characteristic curve(AUC)was 78.1(95%CI,64.2-92.0)for the nomogram,32.9(95%CI,15.3-50.5)for WINROP model,70.2(95%CI,55.8-84.6)for Digirop-Birth model.In external validation group,AUC of the nomogram was also higher than that of WINROP model and Digirop-Birth model(80.2 versus 51.1 and 63.4).The decision curve analysis of the nomogram demonstrated better clinical efficacy than that of WINROP model and Digirop-Birth model.The calibration curves demonstrated a good consistency between the actual severe ROP incidence and the predicted probability.CONCLUSION:Birth weight,multiple births,and noninvasive ventilation are independent predictors of severe ROP.The nomogram has a good ability to predict severe ROP and performed well on internal validation and external validation in southeast China.

Human umbilical cord mesenchymal stem cells derivedexosomes on VEGF-A in hypoxic-induced mice retinal astrocytes and mice model of retinopathy of prematurity

AIM:To observe the effect of human umbilical cord mesenchymal stem cells(hUCMSCs)secretions on the relevant factors in mouse retinal astrocytes,and to investigate the effect of hUCMSCs on the expression of vascular endothelial growth factor-A(VEGF-A)and to observe the therapeutic effect on the mouse model of retinopathy of prematurity(ROP).METHODS:Cultured hUCMSCs and extracted exosomes from them and then retinal astrocytes were divided into control group and hypoxia group.MTT assay,flow cytometry,reverse transcription-polymerase chain reaction(RT-PCR)and Western blot were used to detect related indicators.Possible mechanisms by which hUCMSCs exosomes affect VEGF-A expression in hypoxia-induced mouse retinal astrocytes were explored.At last,the efficacy of exosomes of UCMSCs in a mouse ROP model was explored.Graphpad6 was used to comprehensively process data information.RESULTS:The secretion was successfully extracted from the culture supernatant of hUCMSCs by gradient ultracentrifugation.Reactive oxygen species(ROS)and hypoxia inducible factor-1α(HIF-1α)of mice retinal astrocytes under different hypoxia time and the expression level of VEGF-A protein and VEGF-A mRNA increased,and the ROP cell model was established after 6h of hypoxia.The secretions of medium and high concentrations of hUCMSCs can reduce ROS and HIF-1α,the expression levels of VEGF-A protein and VEGF-A mRNA are statistically significant and concentration dependent.Compared with the ROP cell model group,the expression of phosphatidylinositol 3-kinase(PI3K)/protein kinase B(AKT)/mammalian target of rapamycin(mTOR)signal pathway related factors in the hUCMSCs exocrine group is significantly decreased.The intravitreal injection of the secretions of medium and high concentrations of hUCMSCs can reduce VEGF-A and HIF-1αin ROP model tissues.HE staining shows that the number of retinal neovascularization in ROP mice decreases with the increase of the dose of hUCMSCs secretion.CONCLUSION:In a hypoxia induced mouse retinal astrocyte model,hUCMSCs exosomes are found to effectively reduce the expression of HIF-1αand VEGF-A,which are positively correlated with the concentration of hUCMSCs exosomes.HUCMSCs exosomes can effectively reduce the number of retinal neovascularization and the expression of HIF-1αand VEGF-A proteins in ROP mice,and are positively correlated with drug dosage.Besides,they can reduce the related factors on the PI3K/AKT/mTOR signaling pathway.

Adaptive genetic algorithm with the criterion of premature convergence

To counter the defect of traditional genetic algorithms, an improved adaptivegenetic algorithm with the criterion of premature convergence is provided. The occurrence ofpremature convergence is forecasted using colony entropy and colony variance. When prematureconvergence occurs, new individuals are generated in proper scale randomly based on superiorindividuals in the colony. We use these new individuals to replace some individuals in the oldcolony. The updated individuals account for 30 percent - 40 percent of all individuals and the sizeof scale is related to the distribution of the extreme value of the target function. Simulationtests show that there is much improvement in the speed of convergence and the probability of globalconvergence.

Studies on Endogenous Hormones and Nutritional Physiology Related to the Premature Senescence of Super-hybrid Rice Liangyoupeijiu and Its Parents at Late Growth Stage

The amount of root bleeding sap, contents of chlorophyl , nutrients and hormones in flag leaves of a super-hybrid rice cultivar Liangyoupeijiu （LYPJ） and its parents 9311 and Pei’ai 64S after heading were measured in this study. The re-sults revealed that compared with 9311, the chlorophyl content of LYPJ reduced more quickly after heading, and then kept at a lower level, which was an obvious characteristic of premature senescence. The other physiological indices of LYPJ af-ter heading except abscisic acid （ABA） content in leaf and root also maintained at a lower level than 9311, while al the physiological indices of the sterile line Pei＇ai 64S were lower than LYPJ. So it was speculated that the early-aging characteristic of LYPJ may be inherited from Pei’ai 64S. Al the leaf and root early-aging traits reduced for LYPJ and its parent lines after heading, their leaf and root aged grad-ual y, which indicated that the above-ground （leaf） and under-ground （root） parts cor-related to each other closely, but there was not absolute correlations between them judged from the data.