A Wolbachia symbiont in Aedes aegypti limits infection with dengue, Chikungunya, and Plasmodium.

Wolbachia are maternally inherited intracellular bacterial symbionts that are estimated to infect more than 60% of all insect species. While Wolbachia is commonly found in many mosquitoes it is absent from the species that are considered to be of major importance for the transmission of human pathogens. The successful introduction of a life-shortening strain of Wolbachia into the dengue vector Aedes aegypti that halves adult lifespan has recently been reported. Here we show that this same Wolbachia infection also directly inhibits the ability of a range of pathogens to infect this mosquito species. The effect is Wolbachia strain specific and relates to Wolbachia priming of the mosquito innate immune system and potentially competition for limiting cellular resources required for pathogen replication. We suggest that this Wolbachia-mediated pathogen interference may work synergistically with the life-shortening strategy proposed previously to provide a powerful approach for the control of insect transmitted diseases.

[Effect of L-alanyl-L-glutamine on expression of insulin-like growth factor-1 in intestinal tissues of low-birth-weight newborn rats with hypoxia/reoxygenation-induced intestinal injury].

OBJECTIVE: To study the effect of L-alanyl-L-glutamine (Ala-Gln) on the levels of insulin-like growth factor-1 (IGF-1) and IGF-1 receptor (IGF-1R) in the intestinal tissues of low-birth-weight (LBW) newborn rats with hypoxia/reoxygenation-induced intestinal injury. METHODS: Pregnant rats were fed with or without smoking. The rats born by those fed without smoking were included in group A; for the rats born by those fed with smoking, normal-birth-weight rats were included in group B, and LBW rats were randomly divided into control group (group C), hypoxia/reoxygenation (H/R) group (group D), and Ala-Gln group (group E). Each group consisted of 24 newborn rats. The rats in groups D and E received H/R treatment twice a day for three consecutive days to establish an intestinal injury model; the rats in group E were intraperitoneally injected with Ala-Gln (10 ml/kg) before daily H/R treatment, while those in groups C and D were given an equal dose of normal saline by intraperitoneal injections. On days 4, 7, and 10 after birth, 8 rats were sacrificed in each group to collect intestinal tissues. The IGF-1 levels in intestinal tissues were measured using ELISA, and IGF-1R levels were measured by immunohistochemistry. RESULTS: There were no significant differences in IGF-1 and IGF-1R levels between groups A and B at all time points. The levels of IGF-1 and IGF-1R in group C kept increasing, were higher than those in other groups on day 7 (P<0.05), and reached a normal level on day 10, without significant differences compared with those in groups A and B. Group D had significantly lower IGF-1 and IGF-1R levels than group C at all time points (P<0.05). The levels of IGF-1 and IGF-1R in group E were lower than those in group C on days 4 and 7 (P<0.05), but they increased to approximately the levels in group C and were significantly higher than those in group D on day 10. CONCLUSIONS: Intrauterine and postnatal hypoxia may induce intestinal injury in LBW newborn rats, and parenteral administration of high-dose Ala-Gln can reduce hypoxia-induced intestinal injury. Therefore, Ala-Gln has a protective effect against hypoxia-induced intestinal injury.

Effect of Wolbachia on replication of West Nile virus in a mosquito cell line and adult mosquitoes.

Wolbachia as an endosymbiont is widespread in insects and other arthropods and is best known for reproductive manipulations of the host. Recently, it has been shown that wMelpop and wMel strains of Wolbachia inhibit the replication of several RNA viruses, including dengue virus, and other vector-borne pathogens (e.g., Plasmodium and filarial nematodes) in mosquitoes, providing an alternative approach to limit the transmission of vector-borne pathogens. In this study, we tested the effect of Wolbachia on the replication of West Nile Virus (WNV). Surprisingly, accumulation of the genomic RNA of WNV for all three strains of WNV tested (New York 99, Kunjin, and New South Wales) was enhanced in Wolbachia-infected Aedes aegypti cells (Aag2). However, the amount of secreted virus was significantly reduced in the presence of Wolbachia. Intrathoracic injections showed that replication of WNV in A. aegypti mosquitoes infected with wMel strain of Wolbachia was not inhibited, whereas wMelPop strain of Wolbachia significantly reduced the replication of WNV in mosquitoes. Further, when wMelPop mosquitoes were orally fed with WNV, virus infection, transmission, and dissemination rates were very low in Wolbachia-free mosquitoes and were completely inhibited in the presence of Wolbachia. The results suggest that (i) despite the enhancement of viral genomic RNA replication in the Wolbachia-infected cell line the production of secreted virus was significantly inhibited, (ii) the antiviral effect in intrathoracically infected mosquitoes depends on the strain of Wolbachia, and (iii) replication of the virus in orally fed mosquitoes was completely inhibited in wMelPop strain of Wolbachia.

[Association of Ureaplasma urealyticum infection with bronchopulmonary dysplasia in very low birth weight infants with respiratory distress syndrome].

OBJECTIVE: To study the relationship between Ureaplasma urealyticum (UU) infection in the lower respiratory tract and the incidence of bronchopulmonary dysplasia (BPD) in very low birth weight (VLBW) infants with respiratory distress syndrome (RDS). METHODS: Seventy-three VLBW infants diagnosed with neonatal RDS, who had received at least one dose of pulmonary surfactant, as well as mechanical ventilation, and were hospitalized for over 28 days, were recruited. Endotracheal aspirates were obtained from the lower respiratory tract and examined by real-time PCR to detect UU DNA. The infants were divided into UU infection and non-UU infection groups according to examination results. Clinical characteristics and the incidence of BPD were compared between the two groups. RESULTS: Compared with the non-UU infection group, the UU infection group had a higher rate of maternal vaginal delivery, higher incidence of recurrent nosocomial pulmonary infection and premature rupture of membranes (PROM), and longer durations of PROM, oxygen supplementation, and hospital stay; in addition, the UU infection group had higher plasma IgM level, leukocyte count, and neutrophil count within 3 hours after birth. Among 73 VLBW infants, 45 developed BPD; the incidence of BPD in the UU infection group was 90% (19/21), versus 50% (26/52) in the non-UU infection group (P<0.01). CONCLUSIONS: UU infection in the lower respiratory tract increases the incidence of BPD in VLBW infants with RDS.

[Dynamic changes of intestinal 16S rDNA metagenome in 5 infants].

OBJECTIVE: To investigate the dynamic changes of intestinal 16S rDNA metagenome in healthy infants. METHODS: Seventeen fecal samples were collected at ages of 3 days, 1 month, 6 months and 1 year in 5 infants. Total bacterial DNAs were extracted and submitted high throughout sequencing on the V6 viable region of 16S rDNA. Tags and Operational Taxonomic Units (OTU) were then obtained and analysis of taxonomy, abundance and alpha diversity were performed. RESULTS: In total 2,190.66 Mbp raw data in 17 samples were produced. The OTU numbers ranged from 36 to 308. The dominate phylum included Proteobacteria, Firmicutes and Bacteroidetes and Actinobacteria. The bacterial families>1% increased from only 2-4 per sample on day 3 to 7 at 1 or 6 months, 10 at 12 months. The average npShannon and Simpson index on day 3, at 1 month, 6 months and 1 year were 1.117, 1.460, 2.088, 2.50 and 0.443, 0.408, 0.229, 0.143 respectively. CONCLUSIONS: Infants' intestines harbor abounding bacterial genomes. Distinct individual differences exist in infants in terms of intestinal bacterial abundance and composition. The abundance and diversity of gut bacteria increase over time.

[Clinical significance of dynamic pressure-volume curve in neonatal mechanical ventilation].

OBJECTIVE: To study the characteristics and role of dynamic pressure-volume curve (P-V curve) in neonatal mechanical ventilation. METHODS: A dynamic P-V curve was automatically drawn by the Stephanie ventilator. The slope rate of dynamic P-V curve was measured in 25 neonates who received mechanical ventilation 1, 24, 48 and 72 hrs after ventilation and before weaning from ventilation. Minute-ventilation (MV), mean airway pressure (Pmean), and fraction of inspired oxygen (FiO2) were recorded. The patterns of dynamic P-V curve during abnormal ventilation (resistance to ventilator, part or complete airway obstruction, airway leaking and tracheal catheter exodus) were observed. RESULTS: With the improvement of pulmonary disease, the slope rate of P-V curve and MV increased, Pmean and FiO2 decreased, and the P-V curve shifted to the volume axle. The slope rate of curve 48 and 72 hrs after ventilation and before weaning from ventilation (1.05+/-0.48, 1.10+/-0.42 and 1.13+/-0.37 mL/cmH2O respectively) increased significantly compared with that 1 hr after ventilation (0.76+/-0.53 mL/cmH2O) (p<0.05 or 0.01). Abnormal ventilation led to abnormal appearance of dynamic P-V curve. CONCLUSIONS: The increasing slope rate of dynamic P-V curve and the curve shifting to volume axle in neonatal mechanical ventilation may be associated with the improvement of pulmonary disease. The appearance changes of the curve may be of value in the assessment of abnormal ventilation.

[Value of blood apoH gene expression and urinary NAG and RBP in early diagnosis of renal function damage in neonates].

OBJECTIVE: To study the value of apolipoprotein H (apoH) gene expression in peripheral blood mononuclear cell (PBMC) and urinary N-Acetyl-beta-D-Glucosaminidase (NAG) and retinal-binding protein (RBP) in the early diagnosis of renal function damage in neonates. METHODS: Sixty sick neonates who renal function damage probably occurred were enrolled. The blood and urinary samples were collected twice within 48 hrs following admission, with an interval of 12-24 hrs. Expression of apoH gene in PBMC was determined with RT-PCR. The levels of blood urea nitrogen (BUN) and creatinine, and urinary activities of NAG and RBP were measured with enzymatic reaction. RESULTS: The abnormal rates of blood apoH and urinary NAG and RBP were 73.3%, 83.3% and 76.7%, respectively in the first detection. The second detection for blood apoH and urinary NAG and RBP showed abnormal rates of 70.0%, 66.7% and 76.7%, respectively. There were no significant differences in the abnormal rates between the three markers either in the first or the second detection (P>0.05). Beside there were no significant significances in the abnormal rates between urinary NAG and blood BUN in the second detection, the abnormal rates of blood apoH and urinary NAG and RBP in both detections were significantly higher than those of BUN or creatinine (P<0.01 or 0.05). CONCLUSIONS: There are identical values of blood apoH gene expression and urinary NAG and RBP in the early diagnosis of renal function damage in neonates. The above three markers are more sensitive to early renal function damage than blood BUN and creatinine.

Novel approaches to mitigate primer interaction and eliminate inhibitors in multiplex PCR, demonstrated using an assay for detection of three strawberry viruses.

Multiplex PCR is an important technique for detecting a variety of pathogens simultaneously in a single assay. Previous research has focused on optimising the factors affecting reliable multiplex PCR, including primer design, PCR components and conditions, and inhibitors in samples. In this study, the interaction of primers to form complex secondary structures including visible dimers and invisible "primer clusters", a novel form of primer secondary structure found during this research, were shown to be the most important factors affecting successful multiplex PCR. Approaches to mitigate primer interaction and eliminate inhibitors were tested, including: reduction of primer concentrations especially those with preferential amplification; decrease of PCR extension temperature; increase of extension time and PCR cycles; and addition of bovine serum albumin. Based on these approaches, a multiplex RT-PCR with sensitivity comparable to the simplex PCR for individual viruses was developed for the detection of Raspberry ringspot virus, Strawberry latent ringspot virus and Tomato bushy stunt virus. A plant internal amplification control was also included. These approaches may be useful as a guideline for the development of multiplex PCR protocols for the detection of other pathogens or organisms associated with plants, humans, animals and the environment.

[Efficacy of hyperbaric oxygen therapy under different pressures on neonatal hypoxic-ischemic encephalopathy].

OBJECTIVE: Some research has shown that hyperbaric oxygen (HBO) can decrease the rate of mortality and disability caused by hypoxic-ischemic encephalopathy (HIE) in neonates. However, the HBO pressure used in the clinical reports and the efficacy of HBO are different. This study was designed to investigate the efficacy of HBO therapy under different pressures by observing the changes of peroxidation, antioxidant levels and brain vasomotor regulation factors as well as the score of neonatal behavioral neurological assessment (NBNA) in neonates with HIE after HBO therapy. METHODS: Sixty neonates with HIE were randomly administered with 1.4, 1.5 or 1.6 atmosphere absolute (ATA) of HBO, once daily for seven days. Serum levels of malondialdehyde (MDA), superoxide dismutase (SOD), nitric oxide (NO) and nitric oxide synthase (NOS) were measured before and after HBO therapy. Meanwhile, NBNA and eye ground examination were performed. RESULTS: Serum SOD level increased and serum levels of MDA, NO and NOS decreased significantly after HBO therapy in the three HBO therapy groups (P<0.01). Serum SOD level was significantly higher and serum levels of MDA, NO and NOS were significantly lower in the 1.6 ATA HBO group than those in the 1.4 ATA group after therapy (P<0.05). The 1.6 ATA HBO group also showed increased SOD and decreased MDA levels compared with the 1.5 ATA HBO group after therapy (P<0.05). NBNA scores in the three groups increased significantly after HBO therapy (P<0.05). None of the three HBO therapy group patients showed abnormal eye grounds after therapy. CONCLUSIONS: HBO therapy with 1.4, 1.5 or 1.6 ATA is safe and effective for neonatal HIE. The antioxidant capacity increases with the increasing HBO pressure in neonates with HIE.

[Risk factors for intracranial hemorrhage in very low birth weight infants].

OBJECTIVE: To study the risk factors for intracranial hemorrhage in very low birth weight infants. METHODS: Data from 169 very low birth weight (VLBW) infants (birth weight 1000-1500 g; gestational age 23-36 weeks) were studied retrospectively. Twenty-nine perinatal and postnatal factors were analyzed by Crosstabs Test with SPSS 12.0. A logistic regression analysis was used to identify the risk factors associated with the development of intracranial hemorrhage. RESULTS: Multivariate logistic analysis revealed that rupture of membranes (OR=0.146, 95%CI=0.22-0.964, P < 0.05), 1-minute Apgar score < or = 7 (OR=0.112, 95%CI=0.21-0.591, P < 0.01), pulmonary surfactant therapy (OR=0.110, 95%CI=0.24-0.504, P < 0.01), mechanical ventilation therapy (OR =0.076, 95%CI=0.009-0.668, P < 0.05), mechanical ventilation duration > 72 hrs(OR=0.053, 95%CI=0.007-0.410, P < 0.01), prothrombin time > 20 seconds (OR=4.186, 95%CI=1.606-10.923, P < 0.01), pH value on day 1 of life < 7.25 (OR=0.421, 95%CI=0.179-0.995, P < 0.05) and hyponatremia on day 1 (OR= 0.27, 95%CI=0.077-0.940, P < 0.05) or 2 (OR=2.480, 95%CI=1.053-5.838, P < 0.05) of life were risk factors for intracranial hemorrhage. CONCLUSIONS: 1-minute Apgar score < or =7 and mechanical ventilation treatment were leading risk factors for intracranial hemorrhage, followed by abnormal coagulation and electrolytes related to perinatal asphyxia in VLBW infants. These findings can be used to improve the surveillance and prophylaxis measures in VLBW infants at high risk.

[Risk factors for bronchopulmonary dysplasia in neonates with respiratory distress syndrome].

OBJECTIVE: To identify the risk factors for bronchopulmonary dysplasia (BPD) in neonates with respiratory distress syndrome (RDS). METHODS: Data from 72 patients with RDS (birth weight 1607 +/- 277 g; gestational age 29.47 +/- 2.54 weeks) who were hospitalized for >28 days and who received mechanical ventilation treatment between January 2001 and August 2005 were studied retrospectively. A logistic regression analysis was used to identify the risk factors associated with the development of BPD. RESULTS: Of the 72 patients, 17 developed BPD (23.6%). Uniovariate analysis revealed that in addition to a gestational age of < or = 30 weeks and a birth weight below 1250 g, the times of mechanical ventilation treatment (> or = 2 times), concurrent pulmonary infection and pneumorrhagia, prolonged mechanical ventilation (> or = 5 days), and positive sputum bacterial cultures on 2 occasions were all associated with an increase in the incidence of BPD. Multivariate logistic analysis revealed that birth weight below 1250 g, prolonged mechanical ventilation (> or = 10 days),and positive sputum cultures on 3 or more occasions were independent risk factors for BPD (OR=6.614,14.997 and 39.752 respectively). CONCLUSIONS: The risk for BPD is multifactorial. Preventing small gestational age and low birth weight prematurity, decreasing the duration of mechanical ventilation and treatment of pulmonary infection are necessary to prevent BPD.

Effects of Larval Nutrition on Wolbachia-Based Dengue Virus Interference in Aedes aegypti (Diptera: Culicidae).

In order to assess the broad-scale applicability of field releases of Wolbachia for the biological control of insect-transmitted diseases, we determined the relationship between the larval diet of Aedes aegypti L. mosquitoes infected with Wolbachia strains and their susceptibility to dengue virus (DENV) infection via intrathoracic injection and oral inoculation. Larvae were reared on diets that varied in the quantity of food which had the effect of modifying development time and adult body size. Wolbachia wMel infection was associated with highly significant reductions in dengue serotype 2 (DENV-2) infection rates of between 80 and 97.5% following intrathoracic injection of adults emerging from three diet levels. Reductions were 100% in two diet level treatments following oral inoculation. Similarly, wMelPop infection was associated with highly significant reductions in DENV-2 infection rates of between 95 and 100% for intrathoracic injection and 97.5 and 100% for oral inoculation across diet level treatments. Larval diet level had no significant effect on DENV-2 infection rates in the presence of Wolbachia infection in mosquitoes that were intrathoracically injected with the virus. This indicates that the effectiveness of Wolbachia on vector competence disruption within Ae. aegypti is unlikely to be compromised by variable larval nutrition in field settings.

Low mannose-binding lectin (MBL) levels and MBL genetic polymorphisms associated with the risk of neonatal sepsis: An updated meta-analysis.

BACKGROUND: Relatively low serum mannose-binding lectin (MBL) levels and MBL genetic polymorphisms have been implicated as high risk factors for neonatal sepsis. However, different studies have reported conflicting findings and have generally been underpowered to exclude modest effect sizes. METHODS: Standard methodology of systematic reviews and meta-analyses was followed. PubMed, Embase, Cochrane, Web of Science, and Scopus databases were searched from January 1996 to December 2013. The eligible studies were collected and analyzed using Review Manager 5.2. Meta-Disc version 1.4 was used to describe and calculate sensitivity, specificity, summary receiver operator characteristic (SROC) curves and area under the curve. SROC curve analysis was used to summarize the overall performance. Funnel plots, Egger's test and Begg's test were used to investigate publication bias. RESULTS: Seven studies addressing low MBL levels and MBL genetic polymorphisms (structure variant A/O, A/B of Exon1) were analyzed for susceptibility to neonatal sepsis, respectively. All of these control studies were of reasonable methodological quality. The pooled unadjusted odds ratio showed that low MBL levels were significantly associated with neonatal sepsis (P=0.0002; odds ratio=4.94, 95% confidence interval=2.16-11.29) and MBL genetic polymorphisms were also significantly associated with neonatal sepsis (P=0.03; odds ratio=1.41, 95% confidence interval=1.03-1.94). In subgroup analysis based on gestational age, increased risk was found in the preterm infants in the dominant model (RR 2.33, 95%CI 1.06-5.13, P=0.03). However, no association was observed for term infants in subgroup analysis. Additionally, the SROC curve of low MBL levels in the prediction of neonatal sepsis indicated a poor predictive ability. The area under curve was 0.80 (95% confidence interval=0.74-0.86). CONCLUSION: Currently available evidence shows that neonates with low serum MBL levels are more than four times more likely to have neonatal sepsis compared to those with higher serum MBL levels. Neonates with MBL genetic polymorphisms are also susceptible to developing neonatal sepsis. However, a low serum MBL level was only of moderate value in detecting neonatal sepsis.

The effects and outcomes of electrolyte disturbances and asphyxia on newborns hearing.

OBJECTIVE: To determine the effect of electrolyte disturbances (ED) and asphyxia on infant hearing and hearing outcomes. STUDY DESIGN: We conducted newborn hearing screening with transient evoked otoacoustic emission (TEOAE) test on a large scale (>5000 infants). The effects of ED and asphyxia on infant hearing and hearing outcomes were evaluated. RESULT: The pass rate of TEOAE test was significantly reduced in preterm infants with ED (83.1%, multiple logistic regression analysis: P<0.01) but not in full-term infants with ED (93.6%, P=0.41). However, there was no significant reduction in the pass rate in infants with asphyxia (P=0.85). We further found that hypocalcaemia significantly reduced the pass rate of TEOAE test (86.8%, P<0.01). In the follow-up recheck at 3 months of age, the pass rate remained low (44.4%, P<0.01). CONCLUSION: ED is a high-risk factor for preterm infant hearing. Hypocalcaemia can produce more significant impairment with a low recovery rate.

Cell degeneration is not a primary causer for Connexin26 (GJB2) deficiency associated hearing loss.

Connexin26 (Cx26, GJB2) mutations can induce congenital deafness and are responsible for ∼50% of nonsyndromic hearing loss in children. Mouse models show that Cx26 deficiency induces cochlear development disorder, hair cell loss, and spiral ganglion (SG) neuron degeneration. Hair cell loss and cell degeneration have been considered as a primary causer responsible for Cx26 deficiency associated hearing loss. In this study, by coincidental examination of cochlear postnatal development with recording of auditory brainstem response (ABR) and hair cell function, we found that occurrence of hearing loss in Cx26 knockout (KO) mice was ahead of hair cell loss and cochlear cell degeneration. ABR was absent at the whole-frequency range (8-40 kHz) after birth. However, cochlear cells including SG neurons had no significant degeneration throughout postnatal development. Severe cochlear hair cell loss and SG neuron degeneration were only visible in middle and basal turns, i.e., in middle and high frequency regions, in the adult Cx26 KO mouse cochlea. Functional tests show that hair cells in Cx26 KO mice functioned normally; outer hair cells retained electromotility. These data suggest that cell degeneration is not a primary causer of Cx26 deficiency associated hearing loss. Some mechanisms other than cell degeneration, such as cochlear development disorders, may play an essential role in this common hereditary deafness.