[Effect of breastfeeding on the development of infection-related diseases during hospitalization in late preterm infants in 25 hospitals in Beijing, China].

OBJECTIVE: To investigate the incidence rate of infectious diseases during hospitalization in late preterm infants in Beijing, China, as well as the risk factors for infectious diseases and the effect of breastfeeding on the development of infectious diseases. METHODS: Related data were collected from the late preterm infants who were hospitalized in the neonatal wards of 25 hospitals in Beijing, China, from October 23, 2015 to October 30, 2017. According to the feeding pattern, they were divided into a breastfeeding group and a formula feeding group. The two groups were compared in terms of general status and incidence rate of infectious diseases. A multivariate logistic regression analysis was used to investigate the risk factors for infectious diseases. RESULTS: A total of 1 576 late preterm infants were enrolled, with 153 infants in the breastfeeding group and 1 423 in the formula feeding group. Of all infants, 484 (30.71%) experienced infectious diseases. The breastfeeding group had a significantly lower incidence rate of infectious diseases than the formula feeding group (22.88% vs 31.55%, P=0.033). The multivariate logistic regression analysis showed that breastfeeding was an independent protective factor against infectious diseases (OR=0.534, P=0.004), while male sex, premature rupture of membranes, gestational diabetes mellitus, and asphyxia were risk factors for infectious diseases (OR=1.328, 5.386, 1.535, and 2.353 respectively, P < 0.05). CONCLUSIONS: Breastfeeding can significantly reduce the incidence of infectious diseases and is a protective factor against infectious diseases in late preterm infants. Breastfeeding should therefore be actively promoted for late preterm infants during hospitalization.

[A review on neonatal acute respiratory distress syndrome].

Acute respiratory distress syndrome (ARDS) is a common clinical critical disease and is one of the main causes of death and disability in neonates. The etiology and pathogenesis of neonatal ARDS are complicated. It is an acute pulmonary inflammatory disease caused by the lack of pulmonary surfactant (PS) related to various pathological factors. It is difficult to distinguish neonatal ARDS from other diseases. At present, there is no specific treatment method for this disease. Respiratory support, PS replacement, extracorporeal membrane oxygenation, nutrition support and liquid management are main treatment strategies. This paper reviews the research advance in etiology, clinical characteristics, diagnosis and treatment strategies of neonatal ARDS.

Neonatal outcomes of very preterm infants from a neonatal intensive care center.

BACKGROUND: Information about clinical outcomes of very preterm (VPT) infants in tertiary neonatal intensive care unit (NICU) setting is scant in China. This study aimed to investigate the mortality and morbidity of VPT infants admitted to BaYi Children's Hospital, which serves as a NICU referral center for the city of Beijing, China. METHODS: Retrospectively collected perinatal/neonatal data on all admissions of infants born at <32 weeks of gestational age and subsequently admitted to the VPTNICU from clinical records between October 2010 and September 2011. RESULTS: Totally 729 infants were identified. 90% of VPT infants were outborn. The overall survival of the infants to discharge was 92%, which increased with increasing gestational age (range from 69% at <28 weeks to 99% at 31 weeks). The incidence of bronchopulmonary dysplasia was 4%, retinopathy of prematurity requiring treatment 2%, intraventricular hemorrhage III-IV 6%, and periventricular leukomalacia 2%. 10% of the VPT infants had a major morbidity at discharge. CONCLUSIONS: The outcomes of the VTP infants at this referral NICU were comparable to those in tertiary centers in developed countries. The most common complications were lower than those in other cohorts. Accordingly, high-volume NICU may minimize the adverse effects of VPT infants' transport.

Lipopolysaccharides shapes the human Wharton's jelly-derived mesenchymal stem cells in vitro.

BACKGROUND: Although the expression of toll-like receptors (TLRs) on different types of human mesenchymal stem cells (hMSCs) has recently been reported, controversy remains regarding the presence of TLR4 as well as its engagement and impact on human Wharton's jelly-derived MSCs (hWJ-MSCs). METHODS: In the present study, the expression and role of TLR4 in hWJ-MSCs was investigated using a model of lipopolysaccharide (LPS). Proliferation, apoptosis, and the expression of paracrine factors in hWJ-MSCs primed with LPS were analysed. RESULTS: The expression of TLR4 was high at the RNA level but very low at the protein level. hWJ-MSCs responded to LPS stimulation and initiated a marked up-regulation of inflammatory cytokine (IL-1α, IL-1ß, IL-6, and IL-8) production. Moreover, hWJ-MSCs LPS stimulation resulted in the up-regulation of indoleamine 2,3-dioxygenase [IDO]-1, Cox2, interferon [IFN]-ß, and matrix metalloproteinase (MMP)-2 but a down-regulation of MMP-9, which affect the immunosuppressive potential of hWJ-MSCs. CONCLUSIONS: These data suggest that LPS engagement shapes hWJ-MSCs and results in the production of pro-inflammatory cytokines and inhibitory immune mediators, showing TLR4 agonist induces the hWJ-MSCs polarization to a pro-inflammatory and immunosuppressive state, which may be beneficial for the exploration of the clinical potential of hWJ-MSCs.

[Cloning, purification, and antigenic characterization of three recombinant fragments derived from SARS-CoV S1 domain].

OBJECTIVE: The present study aimed to clone and express three fragments of genomic RNA derived from SARS associated coronavirus (SARS-CoV) S1 domain and to study its immunogenicity. METHODS: The S1 domain gene was amplified by PCR with specific primers and was inserted into the prokaryotic expression vector pQE-30. Three fragments (40-751, 746-1344 and 746-2001 bp) derived from S1 domain produced after the recombinant plasmid (pQE-30/S1) was digested by restriction endonucleases. The three fragments were cloned into pQE-30 and expressed in M15 strains of Escherichia coli. The expression products, designated S1a, S1b and S1c respectively, were purified by Ni affinity chromatography. The immunogenicity was analyzed by Western Blot and ELISA using serologically confirmed sera from SARS patients and the sera from healthy donors was used as control at the same assay. RESULTS: Three recombinant plasmids (pQE-30/S1a, pQE-30/S1b, pQE-30/S1c) were constructed.Fusion proteins with relative molecular mass of 26,700, 22,500 and 46,000 dalton were successfully expressed with amounts of 35%, 35% and 30% of total cell protein and purified by Ni affinity chromatography, respectively. Western Blot and ELISA analysis showed that the S1c protein could be specifically recognized by the sera from SARS patients. CONCLUSION: The recombinant S1c protein was a good immunogen and has the potential to be used as a vaccine against SARS-CoV infection.

[Specific antibodies against the nucleocapsid protein and S1 domain of spike glycoprotein in patients with severe acute respiratory syndrome].

OBJECTIVE: To explore the laws of the appearance of the specific serum antibodies against the nucleocapsid (N) protein and the S1 domain of spike (S) glycoprotein in patients with severe acute respiratory syndrome (SARS) and to evaluate the value of these two proteins to be used as diagnostic makers for SARS. METHODS: The serum samples of 86 patients with SARS confirmed clinically and serologically, 31 males and 55 females, aged 9 approximately 86, with the course of disease of 1 approximately 81 days, and 745 healthy persons were collected during the course. The specific immunoglobulin G (IgG) against N protein, IgG against S1 domain of S protein, and the SARS-CoV IgG in these sera were detected by ELISA. RESULTS: The positive rates of anti-N-IgG, anti S1-IgG, and anti-SARS-CoV IgG were 14% (6/44), 5% (2/44), and 14% (6/44) respectively in the first week of the course of disease, 56% (10/18), 39% (7/18), and 56% (10/18) respectively in the second week, and 100% (24/24), S1-IgG 83% (20/24), and 100% (24/24) respectively in the third week. The agreement rates of the results of anti-N-IgG and anti-s1-IgG with that of the anti-SARS-CoV IgG were 88% (76/86) and 83% (71/86) respectively. The anti-SARS-CoV IgG positive rate in the healthy persons was 1.88% (14.745). CONCLUSION: The N protein and S1 protein may be used as antigens in the development of serological assay for detection of SARS-CoV infection.

Antigenic cross-reactivity between severe acute respiratory syndrome-associated coronavirus and human coronaviruses 229E and OC43.

Cross-reactivity between antibodies to different human coronaviruses (HCoVs) has not been systematically studied. By use of Western blot analysis, indirect immunofluorescence assay (IFA), and enzyme-linked immunosorbent assay (ELISA), antigenic cross-reactivity between severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) and 2 HCoVs (229E and OC43) was demonstrated in immunized animals and human serum. In 5 of 11 and 10 of 11 patients with SARS, paired serum samples showed a > or =4-fold increase in antibody titers against HCoV-229E and HCoV-OC43, respectively, by IFA. Overall, serum samples from convalescent patients who had SARS had a 1-way cross-reactivity with the 2 known HCoVs. Antigens of SARS-CoV and HCoV-OC43 were more cross-reactive than were those of SARS-CoV and HCoV-229E.

Monoclonal antibody-based antigen capture enzyme-linked immunosorbent assay reveals high sensitivity of the nucleocapsid protein in acute-phase sera of severe acute respiratory syndrome patients.

Accurate and timely diagnosis of severe acute respiratory syndrome coronavirus (SARS-CoV) infection is a critical step in preventing another global outbreak. In this study, 829 serum specimens were collected from 643 patients initially reported to be infected with SARS-CoV. The sera were tested for the N protein of SARS-CoV by using an antigen capture enzyme-linked immunosorbent assay (ELISA) based on monoclonal antibodies against the N protein of SARS-CoV and compared to 197 control serum samples from healthy donors and non-SARS febrile patients. The results of the N protein detection analysis were directly related to the serological analysis data. From 27 SARS patients who tested positive with the neutralization test, 100% of the 24 sera collected from 1 to 10 days after the onset of symptoms were positive for the N protein. N protein was not detected beyond day 11 in this group. The positive rates of N protein for sera collected at 1 to 5, 6 to 10, 11 to 15, and 16 to 20 days after the onset of symptoms for 414 samples from 298 serologically confirmed patients were 92.9, 69.8, 36.4, and 21.1%, respectively. For 294 sera from 248 serological test-negative patients, the rates were 25.6, 16.7, 9.3, and 0%, respectively. The N protein was not detected in 66 patients with cases of what was initially suspected to be SARS but serologically proven to be negative for SARS and in 197 serum samples from healthy donors and non-SARS febrile patients. The specificity of the assay was 100%. Furthermore, of 16 sera collected from four patients during the SARS recurrence in Guangzhou, 5 sera collected from 7 to 9 days after the onset of symptoms were positive for the N protein. N protein detection exhibited a high positive rate, 96 to 100%, between day 3 and day 5 after the onset of symptoms for 27 neutralization test-positive SARS patients and 298 serologically confirmed patients. The N protein detection rate continually decreased beginning with day 10, and N protein was not detected beyond day 19 after the onset of symptoms. In conclusion, an antigen capture ELISA reveals a high N protein detection rate in acute-phase sera of patients with SARS, which makes it useful for early diagnosis of SARS.

Preparation and characterization of monoclonal antibodies against S1 domain at N-terminal residues 249 to 667 of SARS-associated coronavirus S1 protein.

OBJECTIVE: To prepare and characterize monoclonal antibodies (mAbs) against S1 protein of severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV). METHODS: 6-His-tagged recombinant fragment at N-terminal residues 249 to 667 of SARS-CoV S1 protein including S-protein receptor-binding domain was expressed in E.coli. The immunogenicity of this S1 domain was identified and used to immunize BALB/c mice for the production of hybridomas. The identification of the mAbs against this S1 domain was performed using indirect enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence assay (IFA) and Western blotting, respectively. RESULTS: Three hybridomas producing mAbs specific to the S1 domain was obtained, with a relative molecular mass of 48,500. None of the 3 mAbs were reactive with human coronaviruses 229E and OC43. Two of the mAbs were IgG2a isotype, and the other was IgG1. CONCLUSIONS: This is the first report of mAbs produced against S-protein receptor-binding domain of SARS-CoV. The 3 S1-specific mAbs may be useful for further study of the function of the S protein and for diagnosis of SARS-CoV infection.

Rapid and efficient preparation of monoclonal antibodies against SARS-associated coronavirus nucleocapsid protein by immunizing mice.

OBJECTIVE: To develop a rapid and efficient method for preparing monoclonal antibodies (mAb) against SARS-associated coronavirus (SARS-Cov) nucleocapsid (N) protein. METHODS: BALB/c mice were injected with the recombinant N protein of SARS-Cov into the foot-pads for the immunization, and the popliteal lymph nodes were isolated 15 d later for mAb-producing hybridomas, from which the mAbs against the N protein of SARS-Cov were screened. The identification of the mAb against the N protein of SARS-Cov was performed using indirect enzyme-linked immunosorbent assay (ELISA), indirect fluorescent-antibody assay (IFA), and Western immunoblotting. RESULTS: Four strains of hybridomas were obtained that produced the mAb specific to the N protein without detectable cross-reactivity with other pathogens. Of the 4 strains, 2 were identified as the immunoglobulin G1 (IgG1) isotype, 1 IgG2a, and the other IgG2b, with affinity constants (Ka) of 2 of the strains being 4.14 x 10(-9)M and 3.19 x 10(-9)M respectively. CONCLUSION: This is the first report on the preparation of mAb that is specific to the SARS-Cov, and the high-specificity and high-affinity mAb produced by the 4 strains of hybridomas provide a basis for further researches on the pathogenesis and early diagnosis of SARS.