[A multicenter study of neonatal stroke in Shenzhen, China]. / 深圳市新生儿脑卒中多中心现况调查.

OBJECTIVES: To investigate the incidence rate, clinical characteristics, and prognosis of neonatal stroke in Shenzhen, China. METHODS: Led by Shenzhen Children's Hospital, the Shenzhen Neonatal Data Collaboration Network organized 21 institutions to collect 36 cases of neonatal stroke from January 2020 to December 2022. The incidence, clinical characteristics, treatment, and prognosis of neonatal stroke in Shenzhen were analyzed. RESULTS: The incidence rate of neonatal stroke in 21 hospitals from 2020 to 2022 was 1/15 137, 1/6 060, and 1/7 704, respectively. Ischemic stroke accounted for 75% (27/36); boys accounted for 64% (23/36). Among the 36 neonates, 31 (86%) had disease onset within 3 days after birth, and 19 (53%) had convulsion as the initial presentation. Cerebral MRI showed that 22 neonates (61%) had left cerebral infarction and 13 (36%) had basal ganglia infarction. Magnetic resonance angiography was performed for 12 neonates, among whom 9 (75%) had involvement of the middle cerebral artery. Electroencephalography was performed for 29 neonates, with sharp waves in 21 neonates (72%) and seizures in 10 neonates (34%). Symptomatic/supportive treatment varied across different hospitals. Neonatal Behavioral Neurological Assessment was performed for 12 neonates (33%, 12/36), with a mean score of (32±4) points. The prognosis of 27 neonates was followed up to around 12 months of age, with 44% (12/27) of the neonates having a good prognosis. CONCLUSIONS: Ischemic stroke is the main type of neonatal stroke, often with convulsions as the initial presentation, involvement of the middle cerebral artery, sharp waves on electroencephalography, and a relatively low neurodevelopment score. Symptomatic/supportive treatment is the main treatment method, and some neonates tend to have a poor prognosis.

qFC6, a major gene for crude fat content and quality in rice.

KEY MESSAGE: qFC6, a major quantitative trait locus for rice crude fat content, was fine mapped to be identical with Wx. FC6 negatively regulates crude fat content and rice quality. Starch, protein and lipids are the three major components in rice endosperm. The lipids content in rice influences both storage and quality. In this study, we identified a quantitative trait locus (QTL), qFC6, for crude fat (free lipids) content through association analysis and linkage analysis. Gene-based association analysis revealed that LOC_Os06g04200, also known as Wx, was the candidate gene for qFC6. Complementation and knockout transgenic lines revealed that Wx negatively regulates crude fat content. Lipid composition and content analysis by gas chromatography and taste evaluation analysis showed that FC6 positively influenced bound lipids content and negatively affected both free lipids content and taste. Besides, higher free lipids content rice varieties exhibit more lustrous appearance after cooking and by adding extra oil during cooking could improve rice luster and taste score, indicating that higher free lipids content may make rice more lustrous and delicious. Together, we cloned a QTL coordinating rice crude fat content and eating quality and assisted in uncovering the genetic basis of rice lipid content and in the improvement of rice eating quality.

Self-floating capsule of algicidal bacteria Bacillus sp. HL and its performance in the dissolution of Microcystis aeruginosa.

Algicidal bacteria is considered as an efficient and environmentally friendly approach to suppress Microcystis aeruginosa (M. aeruginosa). However, algicidal bacteria in natural water is limited during the practical application due to the interference of external factors and the low reuse capability. In this study, a bio-degradation capsule for M. aeruginosa is prepared by bio-compatible sodium alginate (SA) compositing with eco-friendly ethyl cellulose (EC) to improve the property and reuse capability of algicidal bacteria. Bacterial strain HL was well immobilized and the capsule was obtained with 2% of SA, 3% of calcium chloride (CaCl2) and 3% of EC. It has been proved that capsules immobilizing bacteria HL shows considerable advantage over traditional bio-treatment systems (free-living bacteria) and good reusable performance. A better algicidal rate of 77.67% ± 1.14% at 7th day was obtained with the use of capsule embedding 50 mL of algicidal bacteria, enhanced by 11.05% comparing with same amount of free-living bacteria. Moreover, the algicidal rate of M. aeruginosa still reached 68.57% ± 2.88% after three times repetitive use. The effect of capsules on the fluorescence and antioxidant system of M. aeruginosa indicated that the photosystems were irreversibly damaged and the antioxidant response of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were significantly induced. Overall, capsules prepared in this study can provide a desirable environment for algicidal bacteria HL and ensure algicidal bacteria to in-situ work well in inhibiting booms of algae.

Longitudinal Study of Brachial-Ankle Pulse Wave Velocity and Change in Estimated Glomerular Filtration Rate among Chinese Adults.

BACKGROUND AND OBJECTIVES: Studies on the association between arterial stiffness and kidney function have generated inconsistent results. Whether arterial stiffness is linked to decline in renal function warrants further study. This study aimed to investigate the association between brachial-ankle pulse wave velocity (baPWV) and longitudinal change in estimated glomerular filtration rate (eGFR) among Chinese adults. METHODS: In this longitudinal study, 8,264 participants in a community-based cohort had baPWV measured in 2010-2011 and were followed in subsequent surveys through to 2016. During each survey visit, fasting blood samples were collected for serum creatinine and eGFR was calculated. Participants were divided into 5 groups (Q1-Q5) by baPWV quintile. The association between baPWV and longitudinal changes in eGFR was assessed using generalized estimating equation models. RESULTS: A total of 8,045 participants were included in the final analysis. The average age was 54 ± 12 years (age range 24-97 years), and mean eGFR was 93.0 ± 18.6 mL/min/1.73 m2. There was an inverse linear association between baseline baPWV and eGFR change rate (p < 0.001). Compared with Q1 (lowest) group, the mean differences and 95% CI in eGFR decrease rate among Q2-Q5 groups were -0.23 (-0.62, 0.16), -0.67 (-1.06, -0.28), -1.11 (-1.50, -0.72), and -1.30 (-1.69, -0.92) mL/min/1.73 m2 per year, respectively, after adjustment for age, gender, and other potential confounders (p trend < 0.0001). For each 100 cm/s increase in baPWV at baseline, the fully adjusted mean difference in eGFR decrease rate was -0.14 mL/min/1.73 m2 per year (95% CI -0.18, -0.10; p < 0.0001). Compared with participants with baPWV < 1,400 cm/s, the fully adjusted mean difference in eGFR decrease rate was -0.92 mL/min/1.73 m2 per year (95% CI -1.18, -0.66) for those with baPWV ≥ 1,400 cm/s (p < 0.0001). CONCLUSIONS: Participants with a higher baPWV at baseline had a greater decrease in eGFR over time. Future studies could examine the relationship between baPWV and decline in renal function in higher risk cohorts, and its potential role in targeting reno-protective interventions to those who may benefit from them most.

Mucins and Tight Junctions are Severely Altered in Necrotizing Enterocolitis Neonates.

OBJECTIVE: This study investigates the expression levels of mucin 1 (MUC1), MUC2, occludin, and zonula occludens-1 (ZO-1) in necrotizing enterocolitis (NEC). STUDY DESIGN: Intestinal specimens of surgical patients suffering from NEC (the NEC group) and intestinal specimens of patients with congenital intestinal atresia (the control group) were collected. Immunohistochemical changes in MUC1, MUC2, occludin, and ZO-1 were compared between the two groups. RESULTS: Our study showed a significant decrease in the expression levels of MUC1 (p = 0.004), MUC2 (p = 0.001), occludin (p = 0.004), and ZO-1 (p = 0.013) in neonates suffering from NEC as compared with the control group. CONCLUSION: Mucins and tight junctions are severely altered in NEC neonates. This finding might provide clues for rupture of the intestinal barrier. Further research is needed to investigate the gene expression as well as the exact mechanisms behind these changes. This will help us better understand the role of the intestinal barrier in NEC. KEY POINTS: · Mucins and tight junctions are severely altered in NEC neonates.. · We first demonstrate that the expression levels of MUC1are obviously reduced in neonates suffering from NEC.. · Expression levels of MUC2, occludin, and ZO-1, are also significantly decreased in neonates suffering from NEC..

[Relationship between serum erythropoietin levels and brain injury in preterm infants].

OBJECTIVE: To study the relationship between the levels of erythropoietin (EPO) in serum and brain injury in preterm infants. METHODS: Three hundred and four preterm infants (gestational age: 28-34 weeks) born between October 2014 and September 2015 were enrolled in this study. Brain injury was diagnosed using cerebral ultrasound and MRI. The levels of EPO, S100 protein, neuron-specific enolase (NSE) and myelin basic protein (MBP) in serum were detected using ELISA. To compare the incidence of brain injury in different serum EPO levels in preterm infants, and the relationship between brain injury and serum EPO levels was analyzed. RESULTS: The incidence rate of brain injury in preterm infants was 41.1% (125/304). The incidence rate of brain injury in the low EPO level group was significantly higher than that in the middle-high EPO level groups (P<0.01). The serum levels of S100 protein, NSE, and MBP in the brain injury groups were significantly higher than in the control group (P<0.01). The serum EPO levels were negatively correlated with serum S100 protein concentration and NSE levels (P<0.05). According to the multiple logistic regression analysis, low gestational age, low birth weight, asphyxia, prolonged mechanical ventilation, anemia and low serum EPO levels were the risk factor for brain injury in preterm infants. CONCLUSIONS: There is a higher incidence rate of brain injury in preterm infants with lower serum EPO levels. The serum EPO levels may be correlated with brain injury in preterm infants.

[The prediction of high-sensitivity C reactive protein for peripheral arterial sclerosis in middle-aged population].

OBJECTIVE: To explore the predictive value of high-sensitivity C reactive protein (hsCRP) in middle-aged population during the peripheral arteriosclerosis. METHODS: Random sampling method was used in the study. In 2006-2007 Kailuan Group health examination of 101,510 employees, using stratified random sampling method to select 5,852 as observational cohort included, in the final with a standard queue 5,440 in December 2009. This study selected to participate in the 2012-2013 health examination cohort as the research object, in accordance with the inclusion criteria ultimately selected survey 3,978, select the epidemiological investigation, physical examination, laboratory testing data analysis. Of the 3 978 subjects, 2,282 were male and 1,696 were female, and the baseline age was (53.80±11.14) years. According to the baseline hsCRP quartile level was divided into four groups for comparison of baseline data, using multiple linear regression analysis between hsCRP and brachial-ankle pulse wave velocity (baPWV). Area under the receiver operating characteristic (ROC) curve (AUC) was used to evaluate the prediction of hsCRP levels in peripheral arteriosclerosis. RESULTS: With increase of hsCRP levels, the survey of baseline levels of baPWV showed increasing trend, (1,445.49±300.55), (1,494.46±307.94), (1,547.67±320.34), (1,621.32±342.53) cm/s, respectively. Multiple linear regression results showed that age, by logarithmic transformation of hsCRP (lghsCRP) level, systolic blood pressure and fasting blood glucose for each additional unit, baPWV levels were increased 266.47, 58.00, 5.02, 39.79 cm/s (P<0.001), and BMI for each additional unit, baPWV level decreased 9.52 cm/s (P=0.030). The prediction of hsCRP in peripheral artery showed that lghsCRP level of AUC to 0.59 (95% CI: 0.57-0.61), lower than the age and systolic blood pressure predicted value AUC (95% CI) of 0.69 (0.67-0.71), 0.75 (0.73-0.77), respectively. CONCLUSION: The hsCRP level could not predict the peripheral arteriosclerosis alone, and the combined age and systolic blood pressure level could have better predictive value.

Neural architecture search via progressive partial connection with attention mechanism.

Differentiable architecture search requires a larger computational consumption during architecture search, and there exists the depth gap problem under deeper network architecture. In this paper, we propose an attention-based progressive partially connected neural architecture search method (PPCAtt-NAS) to address these two issues. First, we introduce a progressive search strategy in the architecture search phase, build up the sophistication of the architecture gradually and perform path-level pruning in stages to bridge the depth gap. Second, we adopt a partial search scheme that performs channel-level partial sampling of the network architecture to further reduce the computational complexity of the architecture search. In addition, an attention mechanism is devised to improve the architecture search capability by enhancing the relevance between the feature channels. Finally, we conduct extensive comparison experiments with state-of-the-art methods on several public datasets, and our method is able to present higher architecture performance.

Mechanistic study on the increase of Microcystin-LR synthesis and release in Microcystis aeruginosa by amino-modified nano-plastics.

Ecological risk of micro/nano-plastics (MPs/NPs) has become an important environmental issue. Microcystin-leucine-arginine (MC-LR) produced by Microcystis aeruginosa (M. aeruginosa) is the most common and toxic secondary metabolites (SM). However, the influencing mechanism of MPs and NPs exposure on MC-LR synthesis and release have still not been clearly evaluated. In this work, under both acute (4d) and long-term exposure (10d), only high-concentration (10 mg/L) exposure of amino-modified polystyrene NPs (PS-NH2-NPs) promoted MC-LR synthesis (32.94 % and 42.42 %) and release (27.35 % and 31.52 %), respectively. Mechanistically, PS-NH2-NPs inhibited algae cell density, interrupted pigment synthesis, weakened photosynthesis efficiency, and induced oxidative stress, with subsequent enhancing the MC-LR synthesis. Additionally, PS-NH2-NPs exposure up-regulated MC-LR synthesis pathway genes (mcyA, mcyB, mcyD, and mcyG) combined with significantly increased metabolomics (Leucine and Arginine), thereby enhancing MC-LR synthesis. PS-NH2-NPs exposure enhanced the MC-LR release from M. aeruginosa via up-regulated MC-LR transport pathway genes (mcyH) and the shrinkage of plasma membrane. Our results provide new insights into the long-time coexistence of NPs with algae in freshwater systems might pose a potential threat to aquatic environments and human health.

Untargeted lipidomics of bronchopulmonary dysplasia induced by hyperoxia exposure in rats.

Background: Bronchopulmonary dysplasia (BPD), characterized by impaired lung development, remains a leading cause of morbidity and mortality in premature infants. The synthesis and metabolism of lipids play a critical role in normal lung development, such as dipalmitoylphosphatidylcholine, a key component of pulmonary surfactant (PS). Therefore, we conducted a lipidomics study of rat lung tissue to explore the changes of pulmonary lipid composition in the progression of BPD disease. Methods: In this study, we exposed neonatal Sprague-Dawley (SD) rats to hyperoxia for 14 days. After hyperoxia exposure, the lung tissues of rats were analyzed pathologically, and untargeted lipidomics was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results: Hematoxylin-eosin (H&E) staining showed that the alveoli enlarged, the number of alveoli decreased and the pulmonary surfactant-associated protein D (SFTPD) decreased in hyperoxia-exposed rats. A total of 620 pulmonary lipids were detected by LC-MS/MS, covering 27 lipid categories. The most common lipids were triacylglycerol (TAG), followed by phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Conclusions: Compared with those rats exposed to normoxic conditions, the lipid levels in the lungs of rats exposed to hyperoxia for 14 days generally decreased, with the levels of TAG and PC decreasing most significantly. In short, our results provide a clue for finding therapeutic targets and biomarkers of a BPD rat model lung liposome.

[Analysis of CYP21A2 gene mutation in one case of congenital adrenal hyperplasia].

CYP21A2 gene mutations in a child with congenital adrenal hyperplasia (CAH), and the child's parents, were detected in the study. The clinical features, treatment monitoring and molecular genetic mechanism of CAH are reviewed. In the study, DNA was extracted from peripheral blood samples using the QIAGEN Blood DNA Mini Kit; a highly specific PCR primer for CYP21A2 gene was designed according to the sequence difference between CYP2lA2 gene and its pseudogene; the whole CYP2lA2 gene was amplified with PrimeSTAR DNA polymerase (Takara), and the amplification product was directly sequenced to detect and analyze CYP2lA2 gene mutation. The child was clinically diagnosed with CAH (21-hydroxylase deficiency, 21-OHD) at the age of 36 days, and the case was confirmed by genetic diagnosis at the age of 1.5 years. The proband had a homozygous mutation at c.293-13C in the second intron of CYP21 gene, while the parents had heterozygous mutations. Early diagnosis and standard treatment of CAH (21-OHD) should be performed to prevent salt-wasting crisis and reduce mortality; bone aging should be avoided to increase final adult height (FAH), and reproductive dysfunction due to oligospermia in adulthood should be avoided. These factors are helpful for improving prognosis and increasing FAH. Investigating the molecular genetic mechanism of CAH can improve recognition and optimize diagnosis of this disease. In addition, carrier diagnosis and genetic counseling for the proband family are of great significance.

Zero-shot learning via visual-semantic aligned autoencoder.

Zero-shot learning recognizes the unseen samples via the model learned from the seen class samples and semantic features. Due to the lack of information of unseen class samples in the training set, some researchers have proposed the method of generating unseen class samples by using generative models. However, the generated model is trained with the training set samples first, and then the unseen class samples are generated, which results in the features of the unseen class samples tending to be biased toward the seen class and may produce large deviations from the real unseen class samples. To tackle this problem, we use the autoencoder method to generate the unseen class samples and combine the semantic features of the unseen classes with the proposed new sample features to construct the loss function. The proposed method is validated on three datasets and showed good results.

Neural architecture search based on dual attention mechanism for image classification.

Deep learning neural networks based on the manual design for image classification tasks usually require a large amount of a priori knowledge and experience from experts; thus, research on designing neural network architectures automatically has been widely performed. The neural architecture search (NAS) method based on the differentiable architecture search (DARTS) ignores the interrelationships within the searched network architecture cells. The optional operations in the architecture search space lack diversity, and the large parametric and non-parametric operations in the search space make the search process inefficient. We propose a NAS method based on a dual attention mechanism (DAM-DARTS). An improved attention mechanism module is introduced to the cell of the network architecture to deepen the interrelationships between the important layers within the architecture by enhancing the attention between them, which improves the accuracy of the architecture and reduces the architecture search time. We also propose a more efficient architecture search space by adding attention operations to increase the complex diversity of the searched network architectures and reduce the computational cost consumed in the search process by reducing non-parametric operations. Based on this, we further analyze the impact of changing some operations in the architecture search space on the accuracy of the architectures. Through extensive experiments on several open datasets, we demonstrate the effectiveness of the proposed search strategy, which is highly competitive with other existing neural network architecture search methods.

Finite-element-analysis of connection strength of assembled camshafts with different cam-bore profiles using tube hydroforming technology.

The assembled camshaft is a novel manufacturing product which connects the cam and the mandrel by tube hydroforming (THF) technology after they are processed separately. However, in the process of THF, the structure of the cam-bores has a crucial influence on the connection strength of the assembled camshafts. Therefore, three kinds of cam-bores with circular structure, isometric-trilateral profile and logarithmic spiral profile are selected for hydroforming with a hollow mandrel (tube) in this study. The finite-element-analysis is carried out by ABAQUS software, the variations of (residual) contact pressure and contact area under different structures are obtained, and the torsional angle variations after assembly are measured. Further, the connection strength of the assembled camshaft under three structures is discussed. The results show that the evaluation of connection strength of the assembled camshaft is affected by many factors, including contact pressure, maximum residual contact pressure, axial and circular residual contact pressure, contact area and its rate, residual contact area percentage and torsional angle. Through the comprehensive analysis of various factors, the torsional angle of the camshaft with circular structure is the largest, i.e. poor connection strength. By contrast, the torsional strength of the camshaft with isometric-trilateral profile is the largest, namely, the best connection strength.

[Risk factors and pathogen distribution in premature infants with nosocomial sepsis].

OBJECTIVE: To investigate the main risk factors and pathogen distribution of nosocomial sepsis among premature infants. METHODS: The clinical data of 3418 hospitalized premature infants from January 2003 to December 2010 were retrospectively analyzed for the risk factors and pathogen distribution of nosocomial sepsis. RESULTS: The incidence of neonatal nosocomial sepsis was 3.10% (106/3418), and the median age at diagnosis of neonatal nosocomial sepsis was 19 (4-48) days. The major pathogens of the infections among these premature infants included gram-positive bacteria (45.2%), especially coagulase-negative Staphylococcus (24.3%), and gram-negative bacteria (41.7%), especially Klebsiella pneumoniae (25.2%), as well as fungus (13.0%). Logistic regression analysis showed that the main risk factors included low birth weight, retention of central venous catheters, and long duration of parenteral nutrition (OR: 3.765, 3.051, and 2.998, respectively; P<0.05). CONCLUSIONS: Low birth weight, retention of central venous catheters, and long duration of parenteral nutrition are the main risk factors for neonatal nosocomial sepsis, whereas the leading pathogen is Klebsiella pneumoniae.

A novel algicidal bacteria isolated from native snail lived in Taihu Lake against algal blooms: identification, degradation kinetic, and algicidal mechanism.

Harmful algal blooms (HABs) impacted negatively the water ecosystem, and produced toxic microcystins that poses toxic effect on liver, nervous, and genital system. The introduction of useful and adaptive algae-degrading microbes or bio-augmentation can be regarded as an efficient way to inhibit the outbreak of HABs. The purpose of this study is to evaluate the application potential of algicidal bacteria named XMC, which is isolated from native snails. Response surface methodology (RSM) experiments showed that self-characteristic and various external conditions affected the actual algae inhibition ability of XMC. In particular, actual algicidal efficiency was strongly depend on the temperature and growth stage of XMC, and the maximum algicidal rate could reach 93.95% within 7 days. The degradation curve of Microcystis aeruginosa was compliant with the first-order kinetic model, which could be used to predict the degradation effect of Microcystis aeruginosa in engineering applications. The analysis results of algae dissolution products showed that algicidal bacteria XMC had both direct and indirect algicidal capacity. In addition, XMC had strong algicidal ability and greater environmental adaptability, and its algae dissolution products were environmentally friendly. All results indicated that XMC had the potential to be used in the bio-degradation of cyanobacteria bloom.

AL-Net: Attention Learning Network Based on Multi-Task Learning for Cervical Nucleus Segmentation.

Cervical nucleus segmentation is a crucial and challenging issue in automatic pathological diagnosis due to uneven staining, blurry boundaries, and adherent or overlapping nuclei in nucleus images. To overcome the limitation of current methods, we propose a multi-task network based on U-Net for cervical nucleus segmentation. This network consists of a primary task and an auxiliary task. The primary task is employed to predict nuclei regions. The auxiliary task, which predicts the boundaries of nuclei, is designed to improve the feature extraction of the main task. Furthermore, a context encoding layer is added behind each encoding layer of the U-Net. The output of each context encoding layer is processed by an attention learning module and then fused with the features of the decoding layer. In addition, a codec block is used in the attention learning module to obtain saliency-based attention and focused attention simultaneously. Experiment results show that the proposed network performs better than the state-of-the-art methods on the 2014 ISBI dataset, BNS, MoNuSeg, and our nucluesSeg dataset.

Mechanisms of hyperventilation-induced lung injuries in neonatal rats.

BACKGROUND: The aim of this study was to investigate the mechanism of early inflammatory injury in neonatal ventilator-induced lung injuries (VILI). METHODS: Newborn rats were randomly assigned to groups and administrated mechanical ventilation with different tidal volumes. Morphological changes in lung tissues were observed, and the levels of interleukin-6 (IL-6), cysteinyl leukotriene mRNA (CysLT1 mRNA), and nuclear factor-κB mRNA (NF-κBp65 mRNA) in lung tissues were analyzed. RESULTS: The ventilation groups exhibited different degrees of inflammatory cell infiltration, which was aggravated as the tidal volume and ventilation time increased. The IL-6 levels of the hyperventilation 5H, conventional ventilation 5H, hyperventilation 3H, control, and normal lung-tissue group were 785.33±39.06, 701.6±33.65, 686.65±46.85, 637.63±40.55, and 635.02±65.78 pg/g, respectively. Hyperventilation increased the levels of IL-6 and NF-κBp65 mRNA as the ventilation time increased, and IL-6 was positively correlated with NF-κBp65 mRNA levels (r=0.72, P<0.01). Longer hyperventilation periods upregulate the level of CysLT1 mRNA. CysLT1 mRNA/GAPDH of the hyperventilation 5H group was 2.14±1.45 (P<0.01). CONCLUSIONS: Mechanical ventilation with a large tidal volume can cause VILI, characterized at an early stage by inflammatory responses and particularly by the increased secretion and invasion of inflammatory cytokines and inflammatory cells. The activation of the NF-κB-IL-6 signaling pathway was an important mechanism for the initiation of VILI. Additionally, CysLT1 was involved in the inflammatory VILI damage, and its upregulation occurred later than that of IL-6.

[Lung fibrosis induced by mechanical ventilation with different tidal volume in neonatal rats].

OBJECTIVE: To study the changes of collagen synthesis following mechanical ventilation with different tidal volume and the possible mechanism. METHODS: Twenty-four neonatal Sprague-Dawley rats were randomized to hyperventilation (tidal volume 25 mL/kg), conventional ventilation (tidal volume 10 mL/kg) and no mechanical ventilation (control group) (n=8 each group). They were sacrificed 5 hrs after ventilation. Left lung samples were used for histopathologic examinations and the detection of connective tissue growth factor (CTGF) expression by immunohistochemistry. Right lung samples were used for the detection of expression of procollagenIII mRNA(PcolIII mRNA), cysteinyl leukotriene mRNA(CysLT1 mRNA)and CTGF mRNA by PCR. RESULTS: The severity of lung injury and fibrosis increased significantly with the increasing tidal volume compared with the control group. Lung CTGF mRNA expression in the hyperventilation group was significantly higher than that in the control group (P<0.05). Lung PcolIII mRNA and CysLT1 mRNA levels increased with the increasing tidal volume when compared with the control group. The differences in PcolIII mRNA and CysLT1 mRNA levels between groups were significant (P<0.05). There was a positive correlation between lung PcolIII mRNA expression and the severity of lung injury (r=0.78,P<0.01). CTGF and CysLT levels were positively correlated with PcolIII expression (r = 0.59,0.86,P<0.01). CONCLUSIONS: Mechanical ventilation using different tidal volume leads to different severities of lung injury, followed by the occurrence of lung fibrosis. The degree of lung fibrosis is consistent with the severity of lung injury. CysLT and CTGF may be involved in the development of lung fibrosis.

[Effect of erythropoietin on apoptosis following hyperoxic lung injury in neonatal rats].

OBJECTIVE: To study the effect of recombinant human erythropoietin (rhEPO) on apoptosis following hyperoxic lung injury in neonatal rats. METHODS: Ninety-six neonatal Sprague-Dawley rats were randomly divided into four groups: air-exposed control, air-exposed rhEPO-treated, hyperoxia-exposed placebo (95% oxygen), and hyperoxia-exposed rhEPO-treated. rhEPO (800 U/kg) was administered 2, 4, and 6 days after air or hyperoxia exposure. The rats were sacrificed 3, 7 and 14 days after air or hyperoxia exposure for the assessment of lung histological changes by hematoxylin and eosin staining (n=8 each time point). p-JNK levels were measured by Western blot. Lung cell apoptosis was evaluated by TUNEL assay. RESULTS: Compared with the air-exposed control group, inflammatory cell infiltration was found at 3 days and increased obviously at 7 days, and widening of the alveolar septa was observed, the number of alveoli decreased and normal alveolarization disappeared at 14 days after hyperoxia exposure in the hyperoxia-exposed placebo group. rhEPO treatment alleviated significantly the hyeroxia-induced alterations in lung pathology. P-JNK protein levels and the number of apoptosis cells decreased significantly in the hyperoxia-exposed rhEPO-treated compared with those in the hyperoxia-exposed placebo group. CONCLUSIONS: rhEPO may reduce apoptosis and thus provide a protective effect against hyperoxic lung injury in neonatal rats. JNK signal pathway may be involved in the protective mechanism.