[Biomechanical analysis of four internal fixations for Pauwels â ¢ femoral neck fractures with defects].

OBJECTIVE: To investigate the biomechanical characteristics of different internal fixations for Pauwels type Ⅲ femoral neck fracture with defect, and provide reference for the treatment of femoral neck fracture. METHODS: Three-dimensional (3D) finite element models of femoral neck fractures were established based on CT images, including fracture and fracture with defects. Four internal fixations were simulated, namely, inverted cannulated screw(ICS), ICS combined with medial buttress plate, the femoral neck system (FNS) and FNS combined with medial buttress plate. The von Mises stress, model stiffness and fracture displacements of fracture models under 2 100 N axial loads were measured and compared. RESULTS: When femoral neck fracture was fixed by ICS and FNS, the peak stress was mainly concentrated on the surface of the screw near the fracture line, and the peak stress of FNS is higher than that of ICS;When the medial buttress plate was combined, the peak stress was increased and transferred to medial buttress plate, with more obvious of ICS fixation. For the same fracture model, the stiffness of FNS was higher than that of ICS. Compared with femoral neck fracture with defects, fracture model showed higher stiffness in the same internal fixation. The use of medial buttress plate increased model stiffness, but ICS increased more than FNS. The fracture displacement of ICS model exceeded that of FNS. CONCLUSION: For Pauwels type Ⅲ femoral neck fracture with defects, FNS had better biomechanical properties than ICS. ICS combined with medial buttress plate can better enhance fixation stability and non-locking plate is recommended. FNS had the capability of shear resistance and needn't combine with medial buttress plate.

[Mortality and cause of death of hospitalized neonates in Weifang, China: a multicenter study]. / æ½åŠå¸‚ä½é™¢æ–°ç”Ÿå„¿ç— æ­»çŽ‡åŠæ­»äº¡åŽŸå› çš„å¤šä¸­å¿ƒç ”ç©¶.

OBJECTIVES: To study the changes in the mortality rate and cause of death of hospitalized neonates in grade A tertiary hospitals in Weifang City of Shandong Province during a 10-year period. METHODS: A retrospective analysis was performed on 461 neonates who died in three grade A tertiary hospitals in Weifang City of Shandong Province from January 1, 2012 to December 31, 2021. The related clinical data were collected to examine the changes of neonatal mortality with time, gestational age (GA) and birth weight (BW). The main causes of death of the neonates were compared between the first 5 years (2012-2016) and the last 5 years (2017-2021) in the period. RESULTS: A total of 43 037 neonates were admitted from 2012 to 2021, among whom 461 died, resulting in a mortality rate of 1.07%. The mortality rate in the last 5 years was significantly lower than that in the first 5 years [0.96% (211/22 059 vs 1.19% (250/20 978); P<0.05]. The mortality rate of neonates decreased with the increases in GA and BW (P<0.05). In the first 5 years, the top three main causes of neonatal death were respiratory distress syndrome (RDS), sepsis, and pneumorrhagia, while in the last 5 years, the top three causes were sepsis, pneumorrhagia, and RDS. The leading cause of death was severe asphyxia for the neonates with a GA of <26 weeks and a BW of <750 g in both the first and last 5 years. For the neonates with a GA of 26-<28 weeks, the leading cause of death changed from RDS in the first 5 years to pneumorrhagia in the last 5 years. For the neonates with a BW of 750-<1 000 g, the leading cause of death changed from pneumorrhagia in the first 5 years to RDS in the last 5 years. For the neonates with a GA of 28-<32 weeks and a BW of 1 000-<1 500 g, the leading cause of death was RDS in both the first and last 5 years. For the neonates with a GA of 32-<37 weeks and a BW of 1 500-<2 500 g, the leading cause of death changed from RDS in the first 5 years to sepsis in the last 5 years. The leading cause of death was sepsis for the neonates with a GA of 37-<42 weeks and a BW of 2 500-<4 000 g in both the first and last 5 years. CONCLUSIONS: The mortality rate of neonates in the grade A tertiary hospitals in Weifang City of Shandong Province has been decreasing in the past 10 years, and it decreases with the increases in GA and BW. Sepsis, RDS, and pneumorrhagia are the leading causes of neonatal death. The mortality rate caused by RDS decreases from the first 5 years to the last 5 years, while the mortality rate caused by sepsis or pneumorrhagia increases from the first 5 years to the last 5 years. Therefore, reducing the incidence rates of sepsis, RDS, and pneumorrhagia is the key to reducing neonatal mortality.

[Risk factors for elevated serum total bile acid in preterm infants].

OBJECTIVE: To study the risk factors for elevated serum total bile acid (TBA) in preterm infants. METHODS: A retrospective analysis was performed for the clinical data of 216 preterm infants who were admitted to the neonatal intensive care unit. According to the presence or absence of elevated TBA (TBA >24.8 µmol/L), the preterm infants were divided into elevated TBA group with 53 infants and non-elevated TBA group with 163 infants. A univariate analysis and an unconditional multivariate logistic regression analysis were used to investigate the risk factors for elevated TBA. RESULTS: The univariate analysis showed that there were significant differences between the elevated TBA group and the non-elevated TBA group in gestational age at birth, birth weight, proportion of small-for-gestational-age infants, proportion of infants undergoing ventilator-assisted ventilation, fasting time, parenteral nutrition time, and incidence of neonatal respiratory failure and sepsis (P<0.05). The unconditional multivariate logistic regression analysis showed that low birth weight (OR=3.84, 95%CI: 1.53-9.64) and neonatal sepsis (OR=2.56, 95%CI: 1.01-6.47) were independent risk factors for elevated TBA in preterm infants. CONCLUSIONS: Low birth weight and neonatal sepsis may lead to elevated TBA in preterm infants.

[Diagnostic value and influencing factors for amplitude-integrated EEG in brain injury in preterm infants].

OBJECTIVE: To study the diagnostic value and influencing factors for amplitude-integrated EEG (aEEG) in brain injury in preterm infants. METHODS: One hundred and sixteen preterm infants with a gestational age (GA) between 27 weeks and 36(+6) weeks were enrolled as subjects. The aEEG scores of all preterm infants were obtained within 6 hours after birth. According to the diagnostic results, the 116 preterm infants were divided into two groups: brain injury (n=63) and non-brain injury (n=53). The risk factors for brain injury were evaluated using logistic regression analysis. According to the aEEG results, the 116 preterm infants were divided into two groups: normal aEEG (n=58) and abnormal aEEG (n=58). The influencing factors for aEEG results in preterm infants were determined using univariate analysis. RESULTS: The brain injury group had a significantly higher rate of abnormal aEEG than the non-brain injury group (83% vs 11%; P<0.05). The infants in the brain injury group from two different GA subgroups (27-33(+6) weeks and 34-36(+6) weeks) had significantly lower aEEG scores than the non-brain injury group from corresponding GA subgroups (P<0.01). Logistic regression analysis showed that low GA (<32 weeks), low birth weight (<1 500 g), abnormal placenta, fetal membranes, and umbilical cord, and hypertension during pregnancy were high-risk factors for brain injury (P<0.05). There were significant differences in GA, birth weight, abnormal placenta, fetal membranes, and umbilical cord, and hypertension during pregnancy between the normal and abnormal aEEG groups (P<0.05). CONCLUSIONS: The risk factors for brain injury are consistent with the influencing factors for aEEG results in preterm infants, suggesting that aEEG contributes to the early diagnosis of brain injury.

Defective antiviral CD8 T-cell response and viral clearance in the absence of c-Jun N-terminal kinases.

The c-Jun N-terminal kinase (JNK) signalling pathway appears to act as a critical intermediate in the regulation of lymphocyte activation and proliferation. The majority of studies on the importance of JNK are focused on its role in T helper responses, with very few reports addressing the mechanisms of JNK in governing CD8 T-cell-mediated immunity. By using a well-defined mousepox model, we demonstrate that JNK is involved in CD8(+) T-cell-mediated antiviral responses. Deficiency of either JNK1 or JNK2 impaired viral clearance, subsequently resulting in an increased susceptibility to ectromelia virus in resistant mice. The impairment of CD8 responses in JNK-deficient mice was not directly due to an inhibition of effector T-cell expansion, as both JNK1 and JNK2 had limited effect on the activation-induced cell death of CD8(+) T cells, and only JNK2-deficient mice exhibited a significant change in CD8(+) T-cell proliferation after acute ectromelia virus infection. However, optimal activation of CD8(+) T cells and their effector functions require signals from both JNK1 and JNK2. Our results suggest that the JNK pathway acts as a critical intermediate in antiviral immunity through regulation of the activation and effector function of CD8(+) T cells rather than by altering their expansion.

[Risk factors for Tourette syndrome].

OBJECTIVE: To identify the risk factors for Tourette syndrome (TS) in children. METHODS: Through a genetic epidemiologic case control study, segregation ratio was estimated using the method of Li-Manted-Gart in 80 children with TS. Heritability for the first- and second-degree relatives was estimated using the Falconer regression method. In addition, the 80 children and 80 controls with other diseases were evaluated using the Family Environment Scale and a self-designed questionnaire. Risk factors for TS were investigated using single factor and multifactor regression analysis. RESULTS: The segregation ratio of TS was 0.1176. Heritabilities for the first- and second-degree relatives were (49.7±2.6)% and (21.5±3.4)% respectively. The weighted mean heritability of the first-degree and second-degree relatives was (39.5±2.1)%. Significantly decreased scores were noted in independence, active-recreational orientation and organization and increased scores were noted in the conflict and control in the TS group compared with the control group (P<0.01). Single factor analysis indicated that the risk factors for TS included family history, type of home education, maternal smoking, family conflict, low level of parental education, family control and fetal anoxia. Multifactor regression analysis indicated that there were five important risk factors for TS: family history, family conflict, type of family education, low level of parental education and maternal smoking. CONCLUSIONS: Both heredity and environment are involved in the pathogenesis of TS. The mode of inheritance for TS is polygenic. Improving the living environments of children with a family history of TS is of prime importance.

[SUDHL-4 cell culture in vitro and establishment of mouse tumor model].

This study was designed to investigate the biological and immunological characteristics of a human diffuse large B-cell lymphoma (DLBCL) cell line SUDHL-4, and to establish a mouse model for human DLBCL. SUDHL-4 cells were cultured under different conditions. The morphology and in vitro expression of B-cell and tumor-related markers were detected by microscopy and flow cytometry respectively. To establish the transplanted tumor, the cells were injected subcutaneously into SCID mice. Tumor formation and its histomorphology were analyzed. The results showed that the expression of B cell/tumor-related markers was found on cultured SUDHL-4 cells. A stable mouse model of human DLBCL was successfully established in SCID mice by subcutaneous injection of 10(7) SUDHL-4 cells. Tumor tissue from mice exhibited similar histologic manifestation to those of human DLBCL. It is concluded that the SUDHL-4 cells represent a high consistency in immunological characteristics with human DLBCL. Transplantation of SUDHL-4 cells provides a syngeneic mouse model for the study of human DLBCL.

Nucleotide variation in the NCED3 region of Arabidopsis thaliana and its association study with abscisic acid content under drought stress.

Drought tolerance is a comprehensive quantitative trait that is being understood further at the molecular genetic level. Abscisic acid (ABA) is the main drought-induced hormone that regulates the expression of many genes related to drought responses. 9-cis-epoxycarotenoid dioxygenase (NCED3) is thought to be a key enzyme in ABA biosynthesis. In this paper, we measured the ABA content increase under drought stress, and sequenced and compared the sequence of AtNCED3 among 22 Arabidopsis thaliana accessions. The results showed that the fold of ABA content increase under drought stress was highly variable among these accessions. High density single nucleotide polymorphism (SNP) and insertion/deletion (indel) were found in the AtNCED3 region, on average one SNP per 87.4 bp and one indel per 502 bp. Nucleotide diversity was significantly lower in the coding region than that in non-coding regions. The results of an association study with anova analysis suggested that the 274th site (P<-->S) and the 327th site (P<-->R) amino acid variations might be the cause of ABA content increase of 163av accession under drought stress.

Cell-wall invertases from rice are differentially expressed in Caryopsis during the grain filling stage.

Cell-wall invertase plays an important role in sucrose partitioning between source and sink organs in higher plants. To investigate the role of cell-wall invertases for seed development in rice (Oryza sativa L.), cDNAs of three putative cell-wall invertase genes OsCIN1, OsCIN2 and OsCIN3 were isolated. Semi-quantitative reverse transcription-polymerase chain reaction analysis revealed different expression patterns of the three genes in various rice tissues/organs. In developing caryopses, they exhibited similar temporal expression patterns, expressed highly at the early and middle grain filling stages and gradually declined to low levels afterward. However, the spatial expression patterns of them were very different, with OsCIN1 primarily expressed in the caryopsis coat, OsCIN2 in embryo and endosperm, and OsCIN3 in embryo. Further RNA in situ hybridization analysis revealed that a strong signal of OsCIN2 mRNA was detected in the vascular parenchyma surrounding the xylem of the chalazal vein and the aleurone layer, whereas OsCIN3 transcript was strongly detected in the vascular parenchyma surrounding the phloem of the chalazal vein, cross-cells, the aleurone layer and the nucellar tissue. These data indicate that the three cell-wall invertase genes play complementary/synergetic roles in assimilate unloading during the grain filling stage. In addition, the cell type-specific expression patterns of OsCIN3 in source leaf blades and anthers were also investigated, and its corresponding physiological roles were discussed.

Cloning and expression analysis of rice sucrose transporter genes OsSUT2M and OsSUT5Z.

Two sucrose transporter (SUT) cDNAs, OsSUT2M and OsSUT5Z, were isolated from rice (Oryza sativa L.) by reverse transcription polymerase chain reaction (RT-PCR). Sequencing results indicate they are 1,531 bp and 1,635 bp in length including complete open reading frame 1,506 bp and 1,608 bp, which encode 502 amino acids and 536 amino acids, respectively. The TopPred program suggested that both sucrose transporter proteins, OsSUT2M and OsSUT5Z, consist of potentially 12 transmembrane domains. Semi-quantitative RT-PCR was carried out to investigate the gene expression patterns of OsSUT2M and OsSUT5Z. In vegetative organs, transcripts of OsSUT2M were higher in source leaf blades than in other organs at the same development stage, whereas transcripts of OsSUT5Z were less traceable in all organs investigated. In reproductive organs, both transcripts of these two genes were high in panicles from the booting stage to 7 days after flowering (DAF) and then sharply declined. The potential physiology functions of these two sucrose transporters are discussed.

[Relationship of variation 3057 G-->A of exon 20 of leptin receptor gene to lipid metabolism and fat distribution of children with obesity].

OBJECTIVE: To assess the relationship of the variation of exon 20 of leptin receptor (LEPR) gene to the lipid metabolism and fat distribution of the children with obesity. METHODS: Polymerase chain reaction-restriction fragment length polymorphism(RFLP) and polyacrylamide gel electrophoresis were used to analyze the variation of exon 20 of the LEPR gene of the obesity group(72 obesity children) and the control group(60 healthy children). At the same time, all childrens' serum triglyceride(TG),total cholesterol(TC),high density lipoprotein cholesterol(HDL-C), low density lipoprotein cholesterol(LDL-C), height and weight were measured, and their body mass index(BMI) and fat percent(%fat) were calculated. RESULTS: Three genotypes of exon 20 of LEPR gene were detected in this study. Compared with the control, the frequency of gene variation at 3057 nucleotide G-->A transversion was higher(P<0.05). The concentration of serum TG and the BMI and %fat of the A/A genotype obesity children were higher than those of the G/G genotype ones(P<0.01) but the level of serum HDL of the A/A children were lower than that of the G/G children (P<0.01). As to the G/A genotype children, only their serum TG level was higher than that of the G/G genotype ones(P<0.05). CONCLUSION: The above findings indicated there were polymorphisms in the children with obesity, and those polymorphisms might remarkably affect their lipid metabolism and fat distribution.

[Isolation and characterization of BcMF3, a gene expressed only in maintainer line in Chinese cabbage-pak-choi (Brassica campestris L. ssp. chinensis Makino var. communis Tsen et lee)].

Expression profiling was performed using cDNA-AFLP technology on floral buds of a genic male sterile line (A line) and a maintainer line (B line) in Chinese cabbage pak-choi (Brassica campestris L. ssp. chinensis Makino var. communis Tsen et Lee cv. Aijiaohuang). A differentially expressed cDNA fragment, BA18-T16, was obtained via selective amplification with A18/T16 primer pair. BA18-T16 was specifically associated with the maintainer line, and was expressed only in floral buds revealed by half-quantitative RT-PCR. The 3' end and 5' end sequences of BA18-T16 were obtained by 3' and 5' RACE amplification and the full cDNA,designated as BcMF3, is 2082 bp long containing a 1755 bp open reading frame. BcMF3 shares high homology with Bp19, a pectin methylesterase from Brassica rapa L. with 99% identity at nucleotide level and 85% identity at amino acid level. Suggesting that BcMF3 most likely encodes a pectin methylesterase in Chinese cabbage pak-choi.

[Factors affecting Agrobacterium tumefaciens-mediated transformation of wheat (Triticum aestivum L.)].

Immature embryos and embryo-derived calli from two cultivars of winter wheat (Triticum aestivum L.), BAU146 and BAU170, were transformed with three strains of Agrobacterium tumefaciens, AGL-1, EHA105 and LBA4404 harboring expression vector p3301 or pBTAaB. Both vectors contained bar gene and p3301 contained also gus gene with an intron. The highest explant survival rate and transformation efficiency was obtained when the bacterial cell density was OD600 1.0 with 1 h of infection incubation. Higher osmotic treatment of the explants before inoculation had a positive effect on transformation, while addition of acetosyringone showed ambiguous one, depending on the explant types and bacterium strains. The efficiencies of transformation and transgenic plant regeneration were varied greatly with the bacterium strain, receptor genotype, explant type and its age and physiological state. After optimizing these factors, a large number of PPT-resistant calli and some of PPT-resistant plants were obtained. The resistant plantlet tested and 50% to 60% of the resistant calli were GUS-positive. The integration of foreign DNA into the genome of transgenic plants (3 out 6) was further confirmed by PCR and Southern Blot analysis.