The role of nutrition in analysis of risk factors and short-term outcomes for late-onset necrotizing enterocolitis among very preterm infants: a nationwide, multicenter study in China.

BACKGROUND: Necrotizing enterocolitis (NEC) is a serious gastrointestinal disease, primarily affects preterm newborns and occurs after 7 days of life (late-onset NEC, LO-NEC). Unfortunately, over the past several decades, not much progress has been made in its treatment or prevention. This study aimed to analyze the risk factors for LO-NEC, and the impact of LO-NEC on short-term outcomes in very preterm infants (VPIs) with a focus on nutrition and different onset times. METHOD: Clinical data of VPIs were retrospectively collected from 28 hospitals in seven different regions of China from September 2019 to December 2020. A total of 2509 enrolled VPIs were divided into 2 groups: the LO-NEC group and non-LO-NEC group. The LO-NEC group was divided into 2 subgroups based on the onset time: LO-NEC occurring between 8 ~ 14d group and LO-NEC occurring after 14d group. Clinical characteristics, nutritional status, and the short-term clinical outcomes were analyzed and compared among these groups. RESULTS: Compared with the non-LO-NEC group, the LO-NEC group had a higher proportion of anemia, blood transfusion, and invasive mechanical ventilation (IMV) treatments before NEC; the LO-NEC group infants had a longer fasting time, required longer duration to achieve the target total caloric intake (110 kcal/kg) and regain birthweight, and showed slower weight growth velocity; the cumulative dose of the medium-chain and long-chain triglyceride (MCT/LCT) emulsion intake in the first week after birth was higher and breastfeeding rate was lower. Additionally, similar results including a higher proportion of IMV, lower breastfeeding rate, more MCT/LCT emulsion intake, slower growth velocity were also found in the LO-NEC group occurring between 8 ~ 14d when compared to the LO-NEC group occurring after 14 d (all (P < 0.05). After adjustment for the confounding factors, high proportion of breastfeeding were identified as protective factors and long fasting time before NEC were identified as risk factors for LO-NEC; early feeding were identified as protective factors and low gestational age, grade III ~ IV neonatal respiratory distress syndrome (NRDS), high accumulation of the MCT/LCT emulsion in the first week were identified as risk factors for LO-NEC occurring between 8 ~ 14d. Logistic regression analysis showed that LO-NEC was a risk factor for late-onset sepsis, parenteral nutrition-associated cholestasis, metabolic bone disease of prematurity, and extrauterine growth retardation. CONCLUSION: Actively preventing premature birth, standardizing the treatment of grade III ~ IV NRDS, and optimizing enteral and parenteral nutrition strategies may help reduce the risk of LO-NEC, especially those occurring between 8 ~ 14d, which may further ameliorate the short-term clinical outcome of VPIs. TRIAL REGISTRATION: ChiCTR1900023418 (26/05/2019).

Effect of SMOF lipid emulsion on physical growth and extrauterine growth retardation in very preterm infants: Insights from a multicenter retrospective cohort study.

OBJECTIVE: The aim of this study was to investigate the effects of soybean, medium-chain triacylglycerols (MCTs), olive oil, and fish oil (SMOF) on short-term clinical outcomes, physical growth, and extrauterine growth retardation (EUGR) in very preterm infants. METHODS: This was a multicenter retrospective cohort study of very preterm infants hospitalized in neonatal intensive care units at five tertiary hospitals in China between January 2021 and December 2021. According to the type of fat emulsion used in parenteral nutrition (PN), eligible very preterm infants were divided into the MCTs/long-chain triacylglycerol (MCT/LCT) group and SMOF group. Change in weight z-score (weight Δz) between measurements at birth and at 36 wk of postmenstrual age or at discharge, the incidence of EUGR, and short-term clinical outcomes between the two groups were compared and analyzed. RESULTS: We enrolled 409 very preterm infants, including 205 in the MCT/LCT group and 204 in the SMOF group. Univariate analysis showed that infants in the SMOF group had significantly longer duration of invasive mechanical ventilation and PN, longer days to reach total enteral nutrition, and a higher proportion of maximum weight loss than those in MCT/LCT group (all P < 0.05). After adjusting for the confounding variables, multifactorial logistic regression analysis of short-term clinical outcomes showed that SMOF had protective effects on PN-associated cholestasis (odds ratio [OR], 0.470; 95% confidence interval [CI], 0.266-0.831) and metabolic bone disease of prematurity (OR, 0.263; 95% CI, 0.078-0.880). Additionally, SMOF was an independent risk factor for lower weight growth velocity (ß = -0.733; 95% CI, -1.452 to -0.015) but had no effect on the incidence of EUGR (OR, 1.567; 95% CI, 0.912 to -2.693). CONCLUSION: Compared with MCT/LCT, SMOF can reduce the risk for PN-associated cholestasis and metabolic bone disease of prematurity in very preterm infants and has a negative effect on growth velocity but has no effect on the incidence of EUGR.

Effects of mixed oil emulsion on short-term clinical outcomes in premature infants: A prospective, multicenter, randomized controlled trial.

OBJECTIVE: This study compared the clinical effects of two different lipid emulsions in premature infants with gestational age < 32 weeks (VPI) or birth weight < 1500 g (VLBWI) to provide an evidence-based medicine basis for optimizing intravenous lipid emulsion. METHODS: This was a prospective multicenter randomized controlled study. A total of 465 VPIs or VLBWIs, admitted to the neonatal intensive care unit of five tertiary hospitals in China from March 1, 2021 to December 31, 2021, were recruited. All subjects were randomly allocated into two groups, namely, medium-chain triglycerides/long-chain triglycerides (MCT/LCT) group (n = 231) and soybean oil, medium-chain triglycerides, olive oil, and fish oil (SMOF) group (n = 234). Clinical features, biochemical indexes, nutrition support therapy, and complications were analyzed and compared between the two groups. RESULTS: No significant differences were found in perinatal data, hospitalization, parenteral and enteral nutrition support between the two groups (P > 0.05). Compared with the MCT/LCT group, the incidence of neonates with a peak value of total bilirubin (TB) > 5 mg/dL (84/231 [36.4% vs. 60/234 [25.6%]), a peak value of direct bilirubin (DB) ≥ 2 mg/dL (26/231 [11.3% vs. 14/234 [6.0%]), a peak value of alkaline phosphatase (ALP) > 900 IU/L (17/231 [7.4% vs. 7/234 [3.0%]), and a peak value of triglycerides (TG) > 3.4 mmol/L (13/231 [5.6% vs. 4/234[1.7%]]) were lower in the SMOF group (P < 0.05). Univariate analysis showed that in the subgroup analysis of < 28 weeks, the incidence of parenteral nutrition-associated cholestasis (PNAC) and metabolic bone disease of prematurity (MBDP) were lower in the SMOF group (P = 0.043 and 0.029, respectively), whereas no significant differences were present in the incidence of PNAC and MBDP between the two groups at > 28 weeks group (P = 0.177 and 0.991, respectively). Multivariate logistic regression analysis revealed that the incidence of PNAC (aRR: 0.38, 95% confidence interval [CI]: 0.20-0.70, P = 0.002) and MBDP (aRR: 0.12, 95% CI: 0.19-0.81, P = 0.029) in the SMOF group were lower than that in the MCT/LCT group. In addition, no significant differences were recorded in the incidence of patent ductus arteriosus, feeding intolerance, necrotizing enterocolitis (Bell's stage ≥ 2), late-onset sepsis, bronchopulmonary dysplasia, intraventricular hemorrhage, periventricular leukomalacia, retinopathy of prematurity and extrauterine growth retardation between the two groups (P > 0.05). CONCLUSIONS: The application of mixed oil emulsion in VPI or VLBWI can reduce the risk of plasma TB > 5 mg/dL, DB ≥ 2 mg/dL, ALP > 900 IU/L, and TG > 3.4 mmol/L during hospitalization. SMOF has better lipid tolerance, reduces the incidence of PNAC and MBDP, and exerts more benefits in preterm infants with gestational age < 28 weeks.

Analysis of risk factors for parenteral nutrition-associated cholestasis in preterm infants: a multicenter observational study.

BACKGROUND: It is proposed that the development of parenteral nutrition-associated cholestasis (PNAC) was significantly associated with preterm birth, low birth weight, infection, etc.; however, the etiology and pathogenesis of PNAC are not fully understood. Most of the studies examining PNAC-associated risk factors were single-center studies with relatively small sample sizes. OBJECTIVE: To analyze the risk factors associated with PNAC in preterm infants in China. METHODS: This is a retrospective multicenter observational study. Clinical data on the effect of multiple oil-fat emulsions (soybean oil-medium chain triglycerides-olive oil-fish oil, SMOF) in preterm infants were collected from a prospective multicenter randomized controlled study. A secondary analysis was performed in which preterm infants were divided into the PNAC group and the non-PNAC group based on the PNAC status. RESULTS: A total of 465 cases very preterm infants or very low birth weight infants were included in the study in which 81 cases were assigned to the PNAC group and 384 cases were assigned to the non-PNAC group. The PNAC group had a lower mean gestational age, lower mean birth weight, longer duration of invasive and non-invasive mechanical ventilation, a longer duration oxygen support, and longer hospital stay (P < 0.001 for all). The PNAC group had higher respiratory distress syndrome, hemodynamically significant patent ductus arteriosus, necrotizing enterocolitis (NEC) with stage II or higher, surgically treated NEC, late-onset sepsis, metabolic bone disease, and extrauterine growth retardation (EUGR) compared to the non-PNAC group (P < 0.05 for all). In contrast with the non-PNAC group, the PNAC group received a higher maximum dose of amino acids and fat emulsion, more medium/long-chain fatty emulsion, less SMOF, had a longer duration of parenteral nutrition, lower rates of breastfeeding, higher incidence of feeding intolerance (FI), more accumulated days to achieve total enteral nutrition, less accumulated days of total calories up to standard 110 kcal/kg/day and slower velocity of weight growth (P < 0.05 for all). Logistic regression analysis indicated that the maximum dose of amino acids (OR, 5.352; 95% CI, 2.355 to 12.161), EUGR (OR, 2.396; 95% CI, 1.255 to 4.572), FI (OR, 2.581; 95% CI, 1.395 to 4.775), surgically treated NEC (OR, 11.300; 95% CI, 2.127 ~ 60.035), and longer total hospital stay (OR, 1.030; 95% CI, 1.014 to 1.046) were independent risk factors for the development of PNAC. SMOF (OR, 0.358; 95% CI, 0.193 to 0.663) and breastfeeding (OR, 0.297; 95% CI, 0.157 to 0.559) were protective factors for PNAC. CONCLUSIONS: PNAC can be reduced by optimizing the management of enteral and parenteral nutrition and reducing gastrointestinal comorbidities in preterm infants.

Intercellular mitochondrial transfer as a means of revitalizing injured glomerular endothelial cells.

BACKGROUND: Recent studies have demonstrated that mesenchymal stem cells (MSCs) can rescue injured target cells via mitochondrial transfer. However, it has not been fully understood how bone marrow-derived MSCs repair glomeruli in diabetic kidney disease (DKD). AIM: To explore the mitochondrial transfer involved in the rescue of injured glomerular endothelial cells (GECs) by MSCs, both in vitro and in vivo. METHODS: In vitro experiments were performed to investigate the effect of co-culture with MSCs on high glucose-induced GECs. The transfer of mitochondria was visua lized using fluorescent microscopy. GECs were freshly sorted and ultimately tested for apoptosis, viability, mRNA expression by real-time reverse transcri ptase-polymerase chain reaction, protein expression by western blot, and mitochondrial function. Moreover, streptozotocin-induced DKD rats were infused with MSCs, and renal function and oxidative stress were detected with an automatic biochemical analyzer and related-detection kits after 2 wk. Kidney histology was analyzed by hematoxylin and eosin, periodic acid-Schiff, and immunohistochemical staining. RESULTS: Fluorescence imaging confirmed that MSCs transferred mitochondria to injured GECs when co-cultured in vitro. We found that the apoptosis, proliferation, and mitochondrial function of injured GECs were improved following co-culture. Additionally, MSCs decreased pro-inflammatory cytokines [interleukin (IL)-6, IL-1ß, and tumor necrosis factor-α] and pro-apoptotic factors (caspase 3 and Bax). Mitochondrial transfer also enhanced the expression of superoxide dismutase 2, B cell lymphoma-2, glutathione peroxidase (GPx) 3, and mitofusin 2 and inhibited reactive oxygen species (ROS) and dynamin-related protein 1 expression. Furthermore, MSCs significantly ameliorated functional parameters (blood urea nitrogen and serum creatinine) and decreased the production of malondialdehyde, advanced glycation end products, and ROS, whereas they increased the levels of GPx and superoxide dismutase in vivo. In addition, significant reductions in the glomerular basement membrane and renal interstitial fibrosis were observed following MSC treatment. CONCLUSION: MSCs can rejuvenate damaged GECs via mitochondrial transfer. Additionally, the improvement of renal function and pathological changes in DKD by MSCs may be related to the mechanism of mitochondrial transfer.

High-proportion breast milk feeding is associated with a reduction in the incidence of IVH in very preterm infants.

Objective: To investigate the protective effect of high-proportion breast milk feeding (>50%) on intraventricular hemorrhage (IVH) in very preterm infants (VPIs). Methods: This was a retrospective secondary analysis of a prospective multi-center study, which included 604 VPIs from six hospitals in eastern China between September 2019 and December 2020. The 604 VPIs were divided into two groups according to whether IVH occurred. High-proportion breast milk feeding was defined as breast milk accounting for 51-100% of the total feeding amount both within 7 days and throughout the hospitalization. The IVH grades and the rate of high-proportion breast milk feeding were analyzed. Furthermore, to explore the relationship between high-proportion breast milk feeding and IVH grading, the VPIs' general information, perinatal factors, growth, and nutritional status during hospitalization, and related complications were compared between the two groups. Results: High-proportion breast milk feeding was reported in 63.41% of the VPIs. Furthermore, IVH grades I-II and III-IV were noted in 39.73% (240/604) and 1.66% (10/604) of the VPIs, respectively. Univariate analysis revealed that IVH occurrence in VPIs is influenced by perinatal factors, invasive respiratory therapy, high-proportion breast milk feeding, start feeding with breast milk, the cumulative amount of early parenteral nutrition, postnatal complications, physical growth, and other factors (P < 0.05). After adjustments for gestational age, birth weight, and possible influencing factors through binary logistic regression analysis, the results revealed that high-proportion breast milk feeding and and start feeding with breast milk were associated with a lower total incidence of IVH. Further stratification showed that high-proportion breast milk feeding was associated with a lower incidence of grade I-II IVH. Similarly, after adjusting for the same factors, breast milk feeding >50% in the 1st week was associated with a decreased incidence of total IVH and further stratification showed that it was associated with a lower incidence of grade I-II IVH. Conclusion: High-proportion breast milk feeding and breast milk feeding more than 50% of total intake during the 1st week might be protective factors for IVH grade I-II in VPIs, which further verified the neuroprotective effect of breast milk. In clinical practice, the construction of breast milk banks should be strengthened, breast milk feeding should be encouraged in neonatal intensive care units, and efforts should be made to increase breast milk feeding rates to improve the outcomes of VPIs.

[The Role of Nrf2 Pathway Activation in Hippocampal Neuron Injury of Neonatal Rats with Bilirubin Encephalopathy].

OBJECTIVE: To explore the effect of nuclear factor-erythroid 2-related factor (Nrf2) pathway activation on hippocampal neuron damage in neonatal rats with bilirubin encephalopathy. METHODS: Neonatal rats were randomly assigned to a control group (Control), a model group (Model) and an Nrf2 activator TBHQ (tert-Butylhydroquinone) group (TBHQ), with 20 rats in each group. Bilirubin solution was injected through the cerebellomedullary cistern to establish the neonatal rat model of bilirubin encephalopathy. Neurobehavioral changes were observed in rats and the water content of the brain tissue was measured. Nissl staining was done to observe the damage of hippocampal neurons. TUNEL staining was used to observe the apoptosis of hippocampal neurons. Colorimetric analysis was done to determine the Caspase-3 activity in the hippocampus. The content of malondialdehyde (MDA) and reduced glutathione (GSH) and the activity of superoxide dismutase (SOD) in the hippocampus were examined by chemical analysis. qRT-PCR and Western blot were done to measure the expression of Nrf2 and heme oxygenase-l (HO-1) mRNA and proteins in the hippocampus. RESULTS: After injection of bilirubin into the cerebellomedullary cistern, the young rats in the Model group and the TBHQ group showed different degrees of neurological abnormalities, while those in the control group showed no significant neurobehavioral abnormalities. Compared with the Control group, the Model group had severe neuronal damage, and the water content of brain tissue, the apoptosis of hippocampal neurons, the activity of Caspase-3 and the content of MDA content significantly increased ( P<0.01), while the SOD activity, GSH content, the expression of Nrf2 and HO-1 mRNA and proteins significantly decreased ( P<0.05). Compared with the Model group, neuronal damage was improved in the TBHQ group, and the water content of brain tissue, apoptosis of hippocampal neurons, activity of Caspase-3 and MDA content were all significantly reduced ( P<0.01), while SOD activity, GSH content and the expression of Nrf2 and HO-1 mRNA and proteins were significantly increased ( P<0.05). CONCLUSION: Activation of the Nrf2 pathway can improve hippocampal neuronal damage in neonatal rats with bilirubin encephalopathy and inhibit neuronal apoptosis and the oxidation reaction.

[Safety of two ventilator weaning strategies after high-frequency oscillatory ventilation in preterm infants with respiratory distress syndrome: a prospective randomized controlled trial].

OBJECTIVE: To study the safety of two ventilator weaning strategies after high-frequency oscillatory ventilation (HFOV) for the treatment of neonatal respiratory distress syndrome (NRDS) in preterm infants. METHODS: A prospective randomized controlled trial was conducted for 101 preterm infants with NRDS, with a gestational age of ≤32+6 weeks or a birth weight of ≤1 500 g, who were admitted to the neonatal intensive care unit of Xiamen Maternal and Child Health Hospital from January 1, 2019 to June 30, 2020. The infants underwent HFOV as the preferred treatment. The infants were randomly divided into an observation group (50 infants with direct weaning from HFOV) and a control group (51 infants with weaning after HFOV was switched to conventional mechanical ventilation). The two groups were compared in terms of failure rate of ventilator weaning within 72 hours, changes in blood gas parameters at 2 hours before weaning and at 2 and 24 hours after weaning, respiratory support therapy, incidence rates of complications, and outcome at discharge. RESULTS: There was no significant difference in the failure rate of ventilator weaning within 72 hours (8% vs 14%, P > 0.05). The observation group had a significantly shorter duration of mechanical ventilation than the control group [(64±39) hours vs (88±69) hours, P < 0.05]. There were no significant differences between the two groups in the duration of mechanical ventilation, total oxygen supply time, blood gas parameters before and after ventilator weaning, incidence rates of complications, and outcome at discharge (P > 0.05). CONCLUSIONS: For preterm infants with NRDS, the strategy of weaning directly from HFOV is safe and reliable and can reduce the duration of invasive mechanical ventilation, and therefore, it holds promise for clinical application.

[Clinical effect of an additional maintenance dose of caffeine before ventilator weaning in preterm infants with respiratory distress syndrome: a prospective randomized controlled trial].

OBJECTIVE: To study the clinical effect of an additional maintenance dose (5 mg/kg) of caffeine citrate injection at 1 hour before ventilator weaning in improving the success rate of ventilator weaning in preterm infants (gestational age ≤32 weeks) with respiratory distress syndrome (RDS) on mechanical ventilation. METHODS: A total of 338 preterm infants with RDS (gestational age of ≤32 weeks) who were admitted to the Neonatal Intensive Care Unit of Xiamen Maternal and Child Health Hospital from January 2017 to December 2019 and treated with mechanical ventilation were enrolled. They were randomly divided into an observation group and a routine group, with 169 infants in each group. Both groups received early routine treatment with caffeine. The infants in the observation group received an additional maintenance dose of caffeine citrate injection at 1 hour before ventilator weaning. The two groups were compared in terms of reintubation rate and number of apnea episodes within 48 hours after ventilator weaning, changes in blood gas parameters, blood glucose, heart rate, and mean blood pressure at 2 hours after ventilator weaning, and incidence rates of major complications during hospitalization. RESULTS: Compared with the routine group, the observation group had significantly lower reintubation rate (P=0.034) and number of apnea episodes (≥2 times/day) (P=0.015) within 48 hours after ventilator weaning. Compared with the routine group at 2 hours after ventilator weaning, the observation group had a significantly higher pH value and a significantly lower arterial partial pressure of carbon dioxide (P < 0.05), while there were no significant differences between the two groups in arterial partial pressure of oxygen, blood glucose, heart rate, and mean blood pressure (P > 0.05). During hospitalization, the observation group had a significantly lower incidence rate of intraventricular hemorrhage than the routine group (P=0.048), but there were no significant differences between the two groups in the incidence rates of bronchopulmonary dysplasia, necrotizing enterocolitis, retinopathy of prematurity, and periventricular leukomalacia and mortality rate (P > 0.05). CONCLUSIONS: An additional maintenance dose of caffeine citrate injection at 1 hour before ventilator weaning is safe and effective in improving the success rate of ventilator weaning in preterm infants with RDS and thus holds promise for clinical application.

Role of the CPC sequence in the antioxidant activity of GcGAST protein in E.coli.

Gibberellic acid stimulated transcriptional protein from Gymnadenia conopsea (GcGAST) is a novel member of GA-induced cysteine-rich protein family, which shared 12 highly conserved cysteine residues with other members in C-terminal domain. In the present paper, the recombinant plasmid, as well as two mutants Serine-Proline-Cysteine (SPC) and Cysteine-Proline-Serine (CPS), were constructed to investigate for the first time the effects of the cysteines in Cysteine-Proline-Cysteine (CPC) sequence on the antioxidant activity of GcGAST protein. It was found that E.coli expressing wt GcGAST exhibited significant resistance against exogenous H(2)O(2). Similar phenomenon was observed for E.coli harboring SPC mutant. In contrast, the host cell overexpressing CPS mutant became more sensitive to H(2)O(2). Some studies on the level of inclusion body revealed that wt GcGAST and SPC mutant embedded in Inclusion bodies (IB) could effectively eliminate H(2)O(2), whereas the mutagenesis to Ser of the second Cys residue in CPC sequence gave rise to the compete loss of H(2)O(2)-eliminating ability. Fourier transform Infrared spectroscopy analysis indicated that the IB of CPS mutant contained more ß-sheet secondary structure than wt and SPC mutant. Non-reducing SDS-PAGE combined western-blotting analysis revealed that the disulfide bonds were important for the formation of IBs of wt GcGAST and SPC mutant, whereas non-reducing SDS-PAGE of resolubilized IBs showed that hydrophobic interaction favored the aggregation of IBs in CPS mutant. Taken together, these results suggested that GcGAST possessed antioxidant activity in the level of IB, which made some contribution to cellular resistance to H(2)O(2). More importantly, the second cysteine residue in CPC sequence was more essential for its antioxidant biological function.

[Status and changes of soil nutrients in rhizosphere of Abelmoschus manihot different planting age].

Using soil chemical analysis method and combining with ICP-AES determination of mineral nutrition element content in rhizosphere soil of different planting age Abelmoschus Corolla Results show that along with the increase of planting age, the nitrogen (total N), available P and organic matter in rhizosphere soil of Abelmoschus Corolla content declined year by year and the soil got acidification. Heavy metal element content in agricultural land does not exceed national standards, but the content of element mercury (Hg) in rhizosphere soil of different planting age Abelmoschus Corolla declined. Request of microelement such as manganese (Mn) and zinc (Zn) had a increase tendency, but the content of magnesium (Mg) and sodium (Na) increased, and other nutrient elements had no changed rules or unchanged apparently. Consequently, exploring the change rules of different planting age Abelmoschus Corolla soil in rhizosphere as theoretical guidance of rational fertilization and subducting continuous cropping obstscles.

Asiatic acid inhibits liver fibrosis by blocking TGF-beta/Smad signaling in vivo and in vitro.

Liver fibrosis is a major cause of liver failure, but treatment remains ineffective. In the present study, we investigated the mechanisms and anti-hepatofibrotic activities of asiatic acid (AA) in a rat model of liver fibrosis induced by carbon tetrachloride (CCl(4)) and in vitro in TGF-beta1-stimulated rat hepatic stellate cell line (HSC-T6). Treatment with AA significantly attenuated CCl(4)-induced liver fibrosis and functional impairment in a dosage-dependent manner, including blockade of the activation of HSC as determined by inhibiting de novo alpha smooth muscle actin (a-SMA) and collagen matrix expression, and an increase in ALT and AST (all p<0.01). The hepatoprotective effects of AA on fibrosis were associated with upregulation of hepatic Smad7, an inhibitor of TGF-beta signaling, thereby blocking upregulation of TGF-beta1 and CTGF and the activation of TGF-beta/Smad signaling. The anti-fibrosis activity and mechanisms of AA were further detected in vitro in HSC-T6. Addition of AA significantly induced Smad7 expression by HSC-T6 cells, thereby inhibiting TGF-beta1-induced Smad2/3 activation, myofibroblast transformation, and collagen matrix expression in a dosage-dependent manner. In contrast, knockdown of Smad7 in HSC-T6 cells prevented AA-induced inhibition of HSC-T6 cell activation and fibrosis in response to TGF-beta1, revealing an essential role for Smad7 in AA-induced anti-fibrotic activities during liver fibrosis in vivo and in vitro. In conclusion, AA may be a novel therapeutic agent for liver fibrosis. Induction of Smad7-dependent inhibition of TGF-beta/Smad-mediated fibrogenesis may be a central mechanism by which AA protects liver from injury.

[Effects of redox state of disulfide bonds on the intrinsic fluorescence and denaturation of Trx-fused gibberellin-induced cysteine-rich protein from Gymnadnia conopsea].

In the present paper, thioredoxin-fused gibberellin-induced cysteine-rich protein from Gymnadnia conopsea, desigated as Trx-GcGASA and expressed prokaryotically, was purified and identified by using Ni(2+) -NTA affinity chromatography column and SDS-PAGE, and then its intrinsic fluorescence was investigated in the absence and presence of dithiothreitol (DTT), oxidized glutathione (GSSG), peroxide and guanidine hydrochloride (GdnHCl) by means of steady-state fluorescence spectroscopic methods. It was found that (1) at the neutral pH Trx-GcGASA had maximum fluorescence emission at 305 nm following excitation at different wavelengths varying from 250 to 280 nm, which was ascribed to the fluorescence emission from tyrosine residues. (2) The reduction of disulphide bonds lead to the changes in the relative fluorescence intensity between tyrosine and tryptophan residues from 0.7 to 1.8. (3) Both Tyr and Trp residues underwent 12%-21% decrease in fluorescence intensity with the addition of 0.5 mmol x L(-1) GSSG or 5 mmol x L(-1) peroxide. The latter was roughly consistent with the antioxidative activity reported in vivo. (4) No matter whether 1 mmol x L(-1) DTT was absent or present, the fusion protein could not be fully unfolded with lambda(max) < 350 nm following the treatment of 6 mol x L(-1) GdnHCl. (5) Fusion protein Trx-GcGASA experienced GdnHCl-induced denaturation process, and the unfolding equilibrium curve could be well fitted by using two-state model, giving the Gibbs free energy change (deltaG) of 3.7 kJ x mol(-1). However, it was not the case for reduced Trx-GcGASA protein. The aforementioned experimental results will not only provide some guides to investigate the effects of fusion partner Trx on the unfolding thermodynamics, kinetics and refolding process of Trx-GcGASA, but also will be useful for further studies on the strucuture of GA-induced cysteine-rich protein with the help of spectroscopic methods.

[Smad7 inhibits collagen expression in human hepatic satellite cells in vitro].

OBJECTIVE: To investigate the effect of Smad7 on the expressions of collagen I and alpha-smooth muscle actin (alpha-SMA) in HSC-T6 cell line activated by transforming growth factor-beta1 (TGF-beta1). METHODS: HSC-T6 cells stably expressing M2-flag protein were selected after co-infection of the cells with pTRE-Smad7-M2-flag and pTet-on. The optimal dose of doxycycline for inducing Smad7 was determined, and the effects of Smad7 over-expression on the expressions of collagen I and alpha-SMA in the cells activated by TGF-beta1 and on Smad2/3 phosphorylation were evaluated using Western blotting. RESULTS: The optimal dose of doxycycline for inducing Smad7 expression was 2 mg/L. Smad7 over-expression induced by doxycycline decreased the expressions of collagen I and alpha-SMA in HSC-T6 cells activated by TGF-beta1, and down-regulated the level of Smad2/3 phosphorylation. CONCLUSION: Smad7 over-expression inhibits Smad2/3 phosphorylation, and decreases the expression of collagen I and alpha-SMA in HSC-T6 cells induced by TGF-beta1 to inhibit the progression of liver fibrosis.

[Some medical staff positive for serum SARS coronavirus antibody IgG have only mild symptoms].

OBJECTIVE: To identify patients with SARS coronavirus infection who have only mild symptoms. METHOD: Enzyme-linked immunosorbent assay was employed to detect serum antibody against SARS coronavirus in the lysate of whole SARS coronavirus from 19 SARS patients and 200 medical staff members without obvious SARS symptoms after possible exposure to the virus during routine medical practice. RESULTS: Serum IgG antibody against SARS coronavirus was detected in all the 19 SARS patients, and among the 200 staff members, 20 (10%) were found positive for the antibody but with no obvious or only mild symptoms. CONCLUSION: Serum IgG antibody against SARS coronavirus is positive in a small proportion (around 10%) of the medical staff members exposed to the virus in our hospital, but may not cause obvious symptoms, suggesting SARS coronavirus infection might in some cases have mild or even no clinical manifestations.

[Relation between COX-2 protein expression and biologic behavior of ovarian carcinoma].

OBJECTIVE: To study the relation between cyclooxygenase-2 (COX-2) protein expression and biologic behavior of ovarian carcinoma. METHODS: The level of COX-2 protein expression was detected by Western Blot assay in 54 biopsy specimens from ovarian serous tumor patients and 10 normal ovarian samples. RESULTS: The level of COX-2 protein expression and relative quantity in ovarian serous carcinoma (81.8%, 20.08 +/- 3.53) were statistically higher than those in the benign ovarian serous tumor (0, 15.04 +/- 0.12) and in the normal ovary (0, 15.33 +/- 0.60) (P < 0.05). The level of COX-2 protein expression and relative quantity in borderline ovarian serous tumor (90.0%, 20.61 +/- 3.03) were statistically higher than those in benign ovarian serous tumor and the normal ovary (P < 0.05). The level of COX-2 protein expression and relative quantity were not significantly different from ovarian serous carcinoma and borderline ovarian serous tumor (P > 0.05); as they were between the benign ovarian serous tumor and the normal ovary (P > 0.05). The level of COX-2 protein expression and relative quantity were not significantly different among different clinical stages (I + II and III + IV), different histological grades, with or without ascites or lymphatic metastasis either. CONCLUSION: COX-2 overexpression may be significantly related to the oncogenesis and development of ovarian serous carcinoma, which may be an early diagnostic parameter and, hence, an attractive target for chemopreventive strategy in the treatment of ovarian serous carcinoma.

[Screening of Bacillus thuringiensis strains containing vip3A genes and analysis of gene conservation].

Vip3A, a novel insecticidal protein, is secreted by Bacillus thuringiensis (Bt) during vegetative growth. Vip3A protein possesses insecticidal activity against a wild spectrum of lepidopteran insect larvae. Since the first cloning of vip3A gene from Bt, many other vip3A genes have been isolated. To investigate vip3A genes contribution to Bt and reflect the revolution relationships, the strains containing vip3A genes were screened and gene similarity was analyzed. 114 wild-type Bacillus thuringiensis (Bt) strains isolated from different regions and 41 standard Bt strains from the Institute of Pasteur were screened for the vip3A genes using PCR amplification. 39 strains including B. thuringiensis subsp. kurstaki (Btk) HD-1 were found to contain the vip3A genes. Because acrystallerous strain Cry- B derived from Btk HD-1 was proved not to contain vip3A gene, it suppose that the vip3A gene may be located at the plasmids. Vip3A proteins expressed in these strains were detected with polyclonal antibody by Western blot and 4 strains among them were shown not to express the Vip3A proteins. The vip3A genes amplified from wild-type Bacillus thuringiensis strains S101 and 611 with different levels of activity against lepidopteran insect larvae were cloned into pGEM-T Easy vector. Alignment of these 2 putative Vip3A proteins with 6 others (Vip3A (a), Vip3A(b), Vip3A-S, Vip3A-S184, Vip83 and Vip3V) in the GenBank data base and 2 reported Vip3A proteins (Vip14 and Vip15) showed that vip3A genes are highly conservative. The plasmids pOTP-S101 and pOTP-611 were constructed by in- serting 2 vip3A genes (vip3A-S101 and vip3A-611) into the expression vector pQE30 respectively and were transformed into E. coli M15. E. coli M15 cells harboring the pOTP plasmids were induced with 1 mmol/L IPTG to express 89 kDa protein. Experiments showed that the level of soluble proteins of Vip3A-S101 in E. coli M15[pOTP-S101] and Vip3A-611 in E. coli M15 [pOTP-611] were about 48% and 35% respectively. Bioassay showed that each of these Vip3A proteins had similar toxicity against neonate Spodoptera litura larvae, indicating that some amino acids change had little effect on the insecticidal activity of proteins. Although vip3A genes are conservative, the unknown insecticidal spectrum is still to be brought out. Vip3A genes can be used for the construction of the Bt engineered strains and transgenic plants. In addition, vip3A genes are excellent candidates for delay of the pest resistance due to the difference of the action model from that of Bt delta-endotoxins.

[Cloning and expression product of vip3A gene from Bacillus thuringiensis and analysis of inseceicidal activity].

The vip3 A gene in a size of 2.3 kb amplified from wild-type Bacillus thuringiensis strain S184 by PCR was cloned into pGEM-T Easy vector and its sequence was analysized by DNASTAR. The plasmid pOTP was constructed by inserting vip3A-S184 gene into the expression vector pQE30 and then was transformed into E. coli M15. E. coli M15 cells harbouring the plasmid pOTP were induced with 1 mmol/L IPTG to express 89 kD protein which was confirmed to be Vip3A-S184 by Western blot. Experiments showed that about 19% of Vip3A-S184 proteins were soluble, and others were insoluble proteins and formed inclusion bodies observed by transmission electron microscopy(TEM). The target protein was purified under the native condition and the polyclonal antibody was prepared by immunizing rabbits. The polyclonal antibody was used to detect Vip3A proteins expressed in Bacillus thuringiensis. Bioassay showed that Vip3A-S184 showed a high toxicity against 3 tested insect larvae including Spodoptera exigua, Spodoptera litura and Helicoverpa armigera.