Kinetic model analysis is a useful tool for understanding the regulation and control of cellular metabolism and thus offering a guideline for rational design of high efficiency cell factory. Based on previously published models and experimental measurement of enzyme kinetics data, we developed a kinetic model for the threonine biosynthesis pathway in Escherichia coli. This model integrates the central pathways that produce precursors, ATP and reducing power with the threonine biosynthesis pathway from aspartate. In contrast to the previous models, we considered the energy and reducing power balance rather than artificially set their concentrations. Metabolic control analysis of the model showed that enzymes PTS, G6PDH, HDH etc. have great flux control coefficients on the threonine biosynthesis flux. This indicates higher threonine synthesis flux could be achieved by overexpressing these enzymes.
Escherichia coli ; metabolism ; Industrial Microbiology ; Kinetics ; Metabolic Networks and Pathways ; Models, Biological ; Threonine ; biosynthesis

Objective To evaluate the value of 18F-FDG PET/CT in assessing radiosensitivity enhancement by irisquinone (IR) on rabbit xenografted VX2 lung tumor models.Methods Twenty-four tumor-beating rabbits were randomly divided into 3 groups (8 rabbits/group):group A with radiotherapy alone,group B with combined radiotherapy and IR,and group C without radiotherapy (the control group).18F-FDG PET/CT imaging was performed before radiotherapy and 24 h and one week after radiotherapy.The tumor SUVmax on delayed imaging was calculated in all rabbits.Two rabbits in each group were sacrificed after PET/CT imaging.HE staining was used to assess the differences in cancer cells among groups.Paired t test,one-way analysis of variance and Kaplan-Meier analysis were performed to analyze the data using SPSS 13.0.Results Before radiotherapy,the tumor SUVmax of all the 24 rabbits on standard and delayed imaging were 2.200 ± 0.761 and 3.162 ± 0.833 (t =-5.582,P ＜ 0.01).At 24 h post-radiotherapy,the delayed SUVmax of groups A,B and C were 2.614 ± 0.654,2.349 ± 0.869 and 5.663 ± 1.144,respectively.The differences between pre-radiotherapy and 24 h post-radiotherapy were statistically significant in all three groups (t =2.527,3.620,11.011,all P ＜0.05).One week after radiotherapy,the delayed SUVmax of groups A,B and C were 3.625 ± 1.064,3.058 ±0.850 and 7.424 ± 1.751,respectively.The differences among groups A,B and C were statistically significant (tA∶ B =2.652,tA∶C =3.799,tB∶C =4.366,all P ＜0.05).The cancer cells of group B were fewer than those of groups A and C by pathological findings,which was consistent with 18F-FDG PET/CT results.The survival times of groups A,B and C were (62.375 ±4.534),(69.000 ±4.660) and (54.125 ±5.276) d,respectively.Kaplan-Meier survival curves revealed better survival of group B as compared to groups A and C,respectively (Log-rank,x2 =7.355,16.943,both P ＜ 0.01).Conclusion 18 F-FDG PET/CT is able to evaluate the effect of irisquinone on tumor radiosensitivity enhancement.

Objective To investigate the status of self-care ability and cognition among disabled elderly,and to analyze the relationship between self-care ability and cognition,then analyze their influencing factors.Methods A total of 813 disabled elderly accepted long-term care at community or facility were recruited by stratified sampling method and investigated by socio-demographic questionnaire,activities of daily living and short portable mental status questionnaire.Results The total scores of self-care ability of the long-term care disabled was 32.01±11.59,and the total points of cognition was 3.77±3.24.Disabled elderly with severe disorders of self-care ability had a higher obstacle rate in every cognition ability than those with mild disabilities (P＜0.001).There were differences in orientation and memory function with different persistent disabled time (x2 =11.875,14.758,P＜0.01).Disabled elderly with cognition obstacles have a higher obstacle rate in every self-care aspect than those with normal cognition (P＜0.01).The multiple regression analysis showed that the educational level (β=-0.067),arital status (β=-0.071),disabled persistence time (β=0.121),orientation ability (β=0.403),the amount of cognition obstacles (β=0.443) were the influence factors of Basic Activities of Daily Living(BADL) among disabled elderly ; and disabled persistence time (β=0.116),orientation ability (β=0.417),recalled ability (β=0.275),memorial ability (β=0.189),calculative ability (β=0.257),the amount of cognition obstacles (β=0.358) were the important factors influence Instrumental Activities of Daily Living(IADL).Conclusion The self-care ability and cognition of the long-term care elderly were declining sharply,and influencing each other.It is advisable to offer them direct long-term care service combined with the laws and characteristics of cognition and self-care ability.

To make further study on the mechanism of needling based on the concept of needle-acupointomics.This article aims to reveal the biologic basis and interpret the scientific methods of needling,and to optimize needling prescriptions.The article make a standardized and normalized study on key techniques in clinical therapeutic methods,for the purpose of putting scientific mechanism into the practical usage,and better serving for clinical practice.

Objective To explore the expression levels of immune-related microRNA-146b (miR-146b),microRNA-155 (miR-155) and microRNA-30b(miR-30b) in human breast milk and its relationship with maternal and infant's health.Methods One hundred and thirty-four mothers and their infants from obstetrical department were recruited in the study after delivery.The subjects were divided into 2 groups,breast feeding group(n =86) and formula-feeding group(n =48),and were followed up 3 months after delivery.Breast milk samples were collected at 2-5 days after delivery(colostrum) and 3 months after delivery(mature milk).The expression levels of microRNAs in milk samples were detected by real-time PCR.The relationship between levels of microRNAs and maternal and infant-related factors was analyzed.Results 1.MiR-146b,miR-155 and miR-30b expressions were abundant both in human colostrums (5.950 ± 0.823,3.899 ± 0.920,4.057 ± 0.604) and mature milk (4.840 ± 0.805,2.128 ± 0.969,4.929 ± 0.566).The levels of miR-146b and miR-155 were higher in colostrum than that of mature milk (t =7.716,10.215,all P ＜ 0.01),while the level of miR-30b was higher in mature milk than that of colostrums(t =-8.626,P ＜ 0.0l).2.Additionally,the level of miR-30b was negatively correlated with maternal pre-pregnancy body mass index (r =-0.298,P ＜ 0.01).3.The levels of miR-146b and miR-30b were higher in mothers giving birth by vaginal delivery than those who underwent cesarean section(t =2.356,3.108,all P ＜0.05).4.The levels of miR-146b and miR-155 were higher in colostrum-fed girls than boys (t =-2.204,-2.985,all P ＜ 0.05).5.The level of miR-146b in mature milk was negatively correlated with 3-month-old infant' s Z score of body weight (r =-0.425,P ＜ 0.05) and body length (r =-0.569,P ＜ 0.01).6.During follow-up,the incidence of baby eczema in breast feeding group (8.82％,3/34 cases) was lower than that in formula milk feeding group(29.17％,14/48 cases) (x2 =5.012,P =0.025).Conclusions The levels of immunocompetent microRNAs in human milk are influenced by the lactation period,maternal prepregnancy body mass index,mode of delivery and infant sex.The immune-related microRNAs in human milk could be involved in the regulation of infant's immunity and growth.

Objective To get the information about the geriatric syndromes in the elderly with different age and gender so as to provide the basis for management of the geriatric syndromes.Methods A questionnaire survey was used to investigate and analyze the geriatric syndromes in 2 778 older subjects aged 60 years and above from Zhejiang and Jiangsu province.Results Among all 2 778 old adults,(3.4 ± 1.8)geriatric syndromes in average were found.The difference in geriatric syndromes number between different age groups showed a statistical significance(F =145.135,P＜ 0.001),but a significant difference in geriatric syndromes number between male and female group was not found(t=0.817,P=0.414).On the top incidence rate of geriatric syndromes were daily life ability defects 2 199 cases(79.2％),falls 1 828 cases(65.8％),urinary incontinence 1 356 cases(48.8％),sleeping disorder 1 023 cases(36.8 ％),cognitive impairment 908 cases (32.7 ％) and visual impairment 896 cases (32.3 ％).Among above six geriatric syndromes,the incidence of daily life ability defects,falls,urinary incontinence,sleeping disorder and cognitive impairment seemed to increase with ageing (P＜0.001).The incidence of daily life ability defects,falls and urinary incontinence was higher in males than in females (P＜ 0.05).The incidence of sleeping disorder and cognitive impairment was higher in females than in males(P＜0.05).The elderly patients with 3 or more geriatric syndromes exceeded about 66.4 ％.The most common clusters of geriatric syndromes were daily life ability defects combined with falls and urinary incontinence,which seemed to significantly increase along with ageing (x2=202.523,P＜0.001).Conclusions Geriatric syndromes are common in the elderly,medical care workers should pay attention to the management of the geriatric syndromes,and promote the development of the elderly healthcare.

Objective To explore the function of ERCC2/XPD polymorphisms in the repair of DNA damage induced by UVC. Methods Plas?mids stably expressing ERCC2/XPD rs13181 AA(Lys751)and ERCC2/XPD rs13181 CC(Gln751)were transfected into Chinese hamster ovary cells,and the stable ERCC2 transfected cell lines were obtained. MTT assay was used to compare the inhibitory rates of the transfected cells treated with UVC at different irradiation intensity. The DNA damage repair ability of the transfected cells treated with UVC for 1,3,6 and 24 h was detected by modified comet assay. Results Compared with UV5ERCC2(CC),UV5ERCC2(CC) was more sensitive to UVC with decreased cell viability. DNA damage level of UV5ERCC2(CC) cells was more serious than UV5ERCC2(CC). Conclusion DNA repair capacity of ERCC2/XPD rs13181A allelic is lower than its wild?type,suggesting that ERCC2/XPDpolymorphisms play a critical role in UVC?induced DNA damage repair.

A microfluidic chip with micropillar arrays for three-dimensional (3D) cell culture was designed and validated.The chip consisted of a polydimethylsiloxane (PDMS) channel plate and a glass cover plate.One cell culture chamber composed of two rows of micropillar arrays and two lateral channels for transporting the culture medium were integrated on the PDMS channel plate.The spacing between micropillars directly affects the chip performance, which is critical for the design of the chip.In this work, the spacing between micropillars was optimized by numerical simulation and experimental validation.With the optimized microfluidic chip, the mixture of cells and extracellular matrix mimics could be steadily injected into the cell culture chamber, the nutrients in the culture medium from the lateral channels could quickly diffuse into the chamber, and the cell metabolites could also timely diffuse out of the chamber.To test the stability of the microenvironment in the microfluidic chip, neural stem cells were three-dimensionally cultured.

Objective To investigate the relationship between serum follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL) and clinicopathological features and prognosis of serous ovarian cancer retrospectively. Methods A total of 73 patients with serous ovarian cancer treated in the Department of Obstetrics and Gynecology of Tianjin Medical University General Hospital from January 2000 to December 2015 were included in this study. The relationship between serum FSH, LH, PRL and clinicopathological features was analyzed by Mann-Whitney U method. Kaplan-Meier (K-M) method was used to analyze survival rates of patients with different clinical features. Multivariate Cox proportional hazards regression analysis was used to analyze prognostic factors of serous ovarian cancer patients. Results The mean concentrations of serum FSH and LH were significantly higher in the>50 year-old group than those in the<50 year-old group (P<0.05). The mean concentrations of FSH and LH were significantly higher in menopause group than those in non-menopause group (P<0.05). There were no significant differences in serum levels of FSH and LH in patients with other different clinicopathological features (P>0.05). There was no significant correlation between serum PRL concentration and clinicopathological features (P>0.05). Analysis results showed that poor prognosis of patients was related with high serum levels of FSH (>40.13 IU/L), PRL (>14.96 μg/L) and FIGO stage (Ⅲ+Ⅳ) (P<0.05). There was no significant correlation between serum LH concentration and prognosis (P>0.05). COX regression analysis showed that the serum PRL>14.96 μg/L was risk factor for prognosis of serous ovarian cancer [HR(95%CI): 3.530(1.180-10.557),P=0.024]. Conclusion The serum levels of FSH and LH are significantly increased in postmenopausal women than those in menopause women. The serum level of PRL is correlated with the prognosis of serous ovarian cancer.

This report summarized the nursing experience of caring for twice skin grafts in a patient with enteroatmospheric fistula after trauma.Keys to nursing success including:monitoring vital signs closely to prevent septic shock,blocking enteroatmospheric fistula (EAF) and sucking overflowed intestinal juice timely,promoting the protection of the graft on abdominal wall wounds,strengthing drainage and lavage with the application of abdominal double cannula to control abdominal infection,early nutrion support with parenteral nutrition in combination with trophic enteral nutrition to improve intestinal immune function,and attaching importance to post-traumatic stress disorder.Timely blocking of EAF is the bases of skin graft healing.