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Biomedical subjects

X L Xia

Publications and source records attributed to X L Xia.

13 recordsLinked to original sources
PubMed2005

A two year family based behaviour treatment for obese children.

BACKGROUND: Childhood obesity has become a nutritional problem in China since the 1990s. AIMS: A family based behavioural treatment was developed and tested, to see if its use was feasible in China and to evaluate its impact on obese schoolchildren. METHODS: In a single school in Beijing, 33 obese children were randomly assigned to a treatment group and 35 to a control group. The treatment group participated in a family based behavioural treatment programme for two years. Height and weight were measured every six months for all participants. Blood pressure, cholesterol, and triglyceride levels were measured at baseline and after two years of programme implementation. RESULTS: Body mass index (BMI, kg/m2) was significantly reduced in the treatment group (from 26.6 (1.7) to 24.0 (0.9), 95% CI 2.06 to 3.18) but not in the control group (from 26.1 (1.5) to 26.0 (1.6)). Total cholesterol decreased 5.5% and triglycerides 9.7% in the treatment group. There was a significant correlation between change in BMI and change in triglycerides. There were no significant changes in plasma lipids in the controls. Blood pressure values also decreased significantly in the treatment, but not the control group. CONCLUSIONS: A family based behavioural intervention was feasible to use in treating obesity in schoolchildren in Beijing, China. After two years of implementation, it successfully decreased the degree of obesity, reduced levels of blood pressure, and decreased serum lipids in treatment; there were no significant changes among control children.

Adolescent↗
PubMed1998

PLA2-independent induction of CSF-1 gene expression in growth-arrested fibroblasts.

At the site of a wound or an infection, localized production of colony-stimulating factor-1 (CSF-1) by resident macrophages is chemotactic for circulating monocytes. Several intracellular signaling pathways, including those initiated in response to activation of phospholipase A2 (PLA2) have been proposed to play a role in the regulation of CSF-1 gene expression. The goal of these studies was to determine whether PLA2 is required for the initial increase in CSF-1 gene expression in serum- or IL-1 alpha-stimulated growth-arrested fibroblasts. IL-1 alpha- or serum-stimulation of growth-arrested fibroblasts had no effect on PLA2 enzyme activity and inhibitors of cytosolic or Ca(2+)-independent PLA2 activity had no effect on IL-1 alpha- or serum-mediated increases in CSF-1 mRNA levels. High concentrations of the PLA2 inhibitors, 4-bromophenacyl lactone and quinacrine, resulted in a generalized decrease in cellular mRNA levels. Our results, obtained in fibroblasts, suggest treatment with 4-bromophenacyl lactone or quinacrine, instead of inhibiting PLA2 activity specifically, results in a generalized depression of cellular mRNA levels. These data demonstrate that the initial increase in CSF-1 gene expression in growth-arrested fibroblasts treated with serum or IL-1 alpha occurs through a PLA2-independent mechanism.

Animals↗
PubMed1997

Transcriptional regulation of the mouse CSF-1 gene.

Research in our laboratory is aimed at understanding the cellular and molecular mechanisms that govern colony stimulating factor-1 (CSF-1) gene expression. Our hypothesis is that a basal set of trans-acting factors is bound to the CSF-1 gene during fibroblast proliferation, resulting in constitutive CSF-1 gene expression. Modulation of CSF-1 gene transcription by growth-arrest (decrease) or stimulation of growth-arrested fibroblasts (re-initiate) is mediated by changes in the basal set of factors bound and/or by the addition of stimulus-specific factors. We have extended our hypothesis to include other cell types (monocytes) to determine if mechanisms used to control CSF-1 gene expression in fibroblasts are unique or represent common nontissue-specific regulatory mechanisms. Analysis of CSF-1-CAT reporter constructs in transiently transfected fibroblasts and monocytes was used to identify CSF-1 genomic sequences that affect transcriptional activity. DNase I protection, electrophoretic mobility shift, and methylation interference assays were used to identify the putative cis-acting elements. Results of our study suggest multiple trans-acting factors may regulate CSF-1 gene expression; some may be tissue specific, while others, such as AP1, CTF/NF1, Sp1, and Sp3, are shared in common.

Animals↗
PubMed1995

Susceptibility to hepatocellular carcinoma is associated with genetic variation in the enzymatic detoxification of aflatoxin B1.

Aflatoxin B1 (AFB1) has been postulated to be a hepatocarcinogen in humans, possibly by causing p53 mutations at codon 249. AFB1 is metabolized via the phase I and II detoxification pathways; hence, genetic variation at those loci may predict susceptibility to the effects of AFB1. To test this hypothesis, genetic variation in two AFB1 detoxification genes, epoxide hydrolase (EPHX) and glutathione S-transferase M1 (GSTM1), was contrasted with the presence of serum AFB1-albumin adducts, the presence of hepatocellular carcinoma (HCC), and with p53 codon 249 mutations. Mutant alleles at both loci were significantly overrepresented in individuals with serum AFB1-albumin adducts in a cross-sectional study. Mutant alleles of EPHX were significantly overrepresented in persons with HCC, also in a case-control study. The relationship of EPHX to HCC varied by hepatitis B surface antigen status and indicated that a synergistic effect may exist. p53 codon 249 mutations were observed only among HCC patients with one or both high-risk genotypes. These results indicate that individuals with mutant genotypes at EPHX and GSTM1 may be at greater risk of developing AFB1 adducts, p53 mutations, and HCC when exposed to AFB1. Hepatitis B carriers with the high-risk genotypes may be an even greater risk than carriers with low-risk genotypes. These findings support the existence of genetic susceptibility in humans to the environmental carcinogen AFB1 and indicate that there is a synergistic increase in risk of HCC with the combination of hepatitis B virus infection and susceptible genotype.

Aflatoxin B1↗
PubMed1995

Binding of a CTF/NF1-like protein to the mouse colony-stimulating factor-1 gene promoter.

Circulating and tissue-specific monocytes/macrophages, through production of hydrolytic enzymes and growth factors, can dramatically affect the local tissue environment. Colony-stimulating factor-1 (CSF-1) is a key regulator of monocyte/macrophage cell activity. CSF-1 is produced by stromal elements, including fibroblasts, which are found in all tissues. To understand at the molecular level how changes in CSF-1 gene transcription are initiated in fibroblasts, we set out to identify the cis-acting elements and cognate trans-acting factor(s) that bind regulatory regions of the mouse CSF-1 gene. Analysis of heterologous reporter constructs containing the mouse CSF-1 promoter linked to the bacterial chloramphenicol acetyltransferase (CAT) gene in transiently transfected fibroblasts identified a cis-acting element located between base pairs -88 and -43 of the CSF-1 gene. Electrophoretic mobility-shift assays (EMSAs) and DNase I protection assays with nuclear extracts isolated from proliferating fibroblasts revealed distinct protein binding to the region spanning base pairs -90 to -68. Results from methylation interference assays suggest CTF/NF1 or a CTF/NF1-like factor is the cognate trans-acting factor. Mutation of the putative CTF/NF1 binding site in the CSF-1 promoter lead to a modest decrease in promoter activity in transiently transfected fibroblasts and monocytes. Therefore, we have demonstrated that CTF/NF1 or a CTF/NF1-like protein binds to the CSF-1 gene promoter; however, binding of the CTF/NF1-like protein alone does not significantly effect changes in CSF-1 gene promoter activity.

Animals↗
PubMed1993

Inhibition of colony-stimulating factor-1 promoter activity by the product of the Wilms' tumor locus.

Colony-stimulating factor-1 (CSF-1) is a member of the immediate early gene family, which is expressed in mitogen-stimulated quiescent fibroblasts. The biological effects of CSF-1 are multifaceted and include stimulation of the proliferation and differentiation of myeloid progenitors and activity of circulating monocytes and tissue-specific macrophages. Ablation of circulating levels of biologically active CSF-1 in mice leads to osteopetrosis and sterility, thus implicating a role for CSF-1 in bone remodeling and implantation. Identification of regulatory elements and cognate transcription factors that bind the csf-1 promoter and mediate such diverse expression patterns is of great interest. We identified a sequence element at -273 to -265 (relative to the transcription initiation site) in the murine csf-1 promoter, which contains overlapping consensus sequences for the Wilms' tumor protein (WT1), EGR-1, SP1, and SP3 proteins. WT1 and EGR-1 proteins produced in vitro bound to this sequence, and co-transfection of wt1 with a csf-1-cat reporter plasmid resulted in repression of promoter activity. Interestingly, nuclear extracts prepared from serum-stimulated C3H10T1/2 cells contained predominantly SP1 and SP3 binding activities, which recognized the -273 to -265 site. Thus repression of the csf-1 promoter by WT1 at this site may involve competition between SP1 family transcriptional activators and the WT1 repressor. Colony-stimulating factor-1 may be a physiologically relevant target gene for regulation by the WT1 transcription factor.

Animals↗
PubMed1993

[Diagnosis and treatment of secondary bone cysts].

The article reported 17 cases of confirmed or suspected secondary bone cyst originating from cystic degeneration of pre-existed tumor or tumor-like lesions. Twelve cases were diagnosed as solitary bone cysts pathologically after operation, but their clinical or radiological manifestations were not in keeping with the pathological findings. Among them aggressive or malignant tumors appeared in 6 cases during follow-up and no primary lesions could be found in other 6 cases. The macroscopic features of the lesion of other 5 cases were very similar to a solitary bone cyst, nevertheless, primary tumors were found histologically. The authors held that when dealing with a cystic lesion of bone, it was important, but sometimes difficult to differentiate a solitary bone cyst from a secondary one, and suggested that if the latter was suspected, injection therapy should not be used, but more radical procedures should be taken for treatment instead and the patient should be observed closely for a longer period.

Adolescent↗
PubMed1993

[Aggressive fibromatosis of bone].

Twenty four cases of pathologically diagnosed aggressive fibromatosis of bone were reported. 17 patients were followed for at least 2 years. Among them 4 recurred and the histological findings of their lesional tissues obtained after recurrence remained benign; one case refused radical treatment and the second biopsy done at 3.5 years after the appearance of the tumor showed no malignant changes; but another case died of lung metastasis. The authors suggest that the criteria for final diagnosis of an aggressive fibromatosis of bone are as follows: Besides the pathological findings, the lesion does not recur or metastasize more than 2 years after operation or it does recur, but still shows benign features histologically. As for treatment, marginal or wide excision is the procedure of choice.

Adolescent↗
PubMed1981

Studies on synthesis and relationship between analgesic activity and receptor affinity for 3-methyl fentanyl derivatives.

In the present paper, the synthesis and analgesic activity (mice, i.p. hot plate test) of the derivatives of 3-methyl fentanyl are briefly described. Compound 7302, cis-N-[1-(2-hydroxy-2-phenylethyl)-3-methyl-4-piperidyl]-N-phenylpropionamide (cis: 3-methyl/4-N-phenylpropionamide) is found to be the most potent analgesic agent in this series synthesized by our laboratory (ED50 = 0.0022 mg/kg). The analgesic activity of 7302 is 28 times more potent than that of fentanyl and 6300 times more than that of morphine. The partition coefficients of 10 compounds in the series are determined by high performance liquid chromatography (HPLC) and their log p values are about 3. There are no regular relationships between the analgesic activity and partition coefficients. Study on the specific binding of 8 out of the above 10 compounds to crude synaptic plasma membrane (P2-fraction) of mouse brain demonstrates that there is an excellent statistical linear correlation (r = 0.998) between the analgesic potency and the specific binding affinity. The result shows that the analgesic potency of the derivatives of this series is mainly dependent on binding affinity for opiate receptor.

Analgesics↗