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Biomedical subjects

X Jia

Publications and source records attributed to X Jia.

At least 19 recordsLinked to original sources
PubMed2007

Is the dementia rate increasing in Beijing? Prevalence and incidence of dementia 10 years later in an urban elderly population.

OBJECTIVE: To examine the time trend of dementia morbidity over the past decade in Beijing, China. METHOD: In 1997, 1593 community-dwelling elderly aged 60+ years were examined and followed-up over 2-years to identify incident dementia. A similar cohort study of dementia conducted in the same district 10 years prior was used as historical comparison to examine the time trend of dementia incidence. RESULTS: Forty prevalent dementia cases were identified at the initial examination for a prevalence of 2.51% (95% CI: 1.74-3.28) and 25 incident cases were identified at the follow-up visit for an incidence of 0.90% (0.55-1.25) among residents aged 60+ years. Alzheimer's dementia (AD) was the most common type of dementia in both prevalent and incident cases. CONCLUSION: The prevalence and incidence rates of dementia in Beijing were slightly higher than those 10 years ago, which was partly because of population aging. AD became the most common subtype of dementia.

Aged↗
PubMed2006

Plant stanol ascorbate esters reduce body weight gain through decreased energy absorption in hamsters.

OBJECTIVE: The objective of this study was to determine the effects of disodium ascorbyl phytostanyl phosphate (DAPP), a novel hydrophilic phytostanol analogue, on energy homeostasis, including body weight and intestinal energy absorption, and plasma triglyceride concentrations, in hamsters. METHODS: Male Golden Syrian hamsters (n = 50) were fed for 5 weeks with experimental diets varying in cholesterol and phytostanol content. Diets included (i) non-cholesterol (semipurified diet without added cholesterol), (ii) cholesterol-control (semipurified diet with 0.25% cholesterol), (iii) stanol (cholesterol-control with 1% free phytostanols), (iv) DAPP 0.7% (cholesterol-control with 0.71% DAPP) or (v) DAPP 1.4% (cholesterol-control with 1.43% DAPP). Fecal samples were collected continuously for 3 days on week 3, and fecal energy output was measured by bomb calorimetry. RESULTS: Hamsters fed 1.4% DAPP gained less (P<0.05) weight than hamsters fed non-cholesterol and stanol diets. Diets had no effect on total food consumption or gross energy intake after 5 weeks, but lower (P<0.05) weekly food consumptions in hamsters fed 1.4% DAPP were observed at weeks 1 and 2 of the experiment in comparison to animals fed the non-cholesterol diet. In comparison to non-cholesterol and cholesterol-control diets, DAPP 1.4% increased (P<0.01) fecal energy output by 47 and 46%, respectively. In hamsters supplemented with 1.4% DAPP, plasma triglyceride concentrations were 45% lower (P<0.05) than in cholesterol-control fed hamsters. Furthermore, plasma triglyceride levels in the DAPP 1.4% group was 49% lower (P<0.01) than in the stanol group, despite the fact that both diets contained equivalent amounts of phytostanols. The lower concentration of DAPP (0.7%) also reduced plasma triglycerides (P<0.05) compared with the stanol diet. CONCLUSION: Stanol-ascorbate decreases body weight gain in hamsters, likely due to lower energy absorption at the intestinal level. In addition to its previously observed powerful cholesterol-lowering effect, DAPP has a hypotriglyceridemic function in hamsters.

Animals↗
PubMed2006

Novel locus for X linked recessive high myopia maps to Xq23-q25 but outside MYP1.

BACKGROUND: High myopia is a common genetic variation in most cases, affecting 1-2% of people, and is the fourth most common disorder causing blindness worldwide. Six autosomal dominant loci and one X-linked recessive locus have been reported, but no genes responsible for high myopia have been identified. OBJECTIVE: To report a Chinese family in which six males presented with high myopia consistent with an X linked recessive trait. RESULTS: Affected individuals shared three common features: high myopia, reduced visual acuity, and fundal changes of high myopia. Protan and deutan were observed in the family, but they did not co-segregate with the high myopia phenotype. X-chromosome-wide linkage analysis mapped the high myopia locus to a 25 cM (14.9 Mb) region on Xq23-q25 between DXS1210 and DXS8057, with maximum two point lod scores at theta = 0 of 2.75 and 2.29 for DXS1001 and DXS8059, respectively. CONCLUSIONS: This new myopia locus is outside the linked region of the first high myopia locus (MYP1). Refinement of the linkage region with additional families and screening candidate genes for mutation may lead to the identification of the defect gene.

Adult↗
PubMed2005

A subchronic toxicity study of elemental Nano-Se in Sprague-Dawley rats.

The subchronic toxicity of Nano-Se was compared with selenite and high-selenium protein in rats. Groups of Sprague-Dawley rats (12 males and 12 females per group) were fed diets containing Nano-Se, selenite and high-selenium protein at concentrations of 0, 2, 3, 4 and 5 ppm Se, respectively, for 13 weeks. Clinical observations were made and body weight and food consumption were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry determination. Histopathological examination was performed on selected tissues. At the two higher doses (4 and 5 ppm Se), significant abnormal changes were found in body weight, hematology, clinical chemistry, relative organ weights and histopathology parameters. However, the toxicity was more pronounced in the selenite and high-selenium protein groups than the Nano-Se group. At the dose of 3 ppm Se, significant growth inhibition and degeneration of liver cells were found in the selenite and high-selenium protein groups. No changes attributable to administration of Nano-Se at the dose of 3 ppm Se were found. Taken together, the no-observed-adverse-effect level (NOAEL) of Nano-Se in male and female rats was considered to be 3 ppm Se, equivalent to 0.22 mg/kg bw/day for males and 0.33 mg/kg bw/day for females. On the other hand, the NOAELs of selenite and high-selenium protein in males and females were considered to be 2 ppm Se, equivalent to 0.14 mg/kg bw/day for males and 0.20 mg/kg bw/day for females. In addition, studies have shown that Nano-Se has a similar bioavailability in rat, and much less acute toxicity in mice compared with selenite. In conclusion, Nano-Se is less toxic than selenite and high-selenium protein in the 13-week rat study.

Administration, Oral↗
PubMed2004

Codalike multiple scattering of elastic waves in dense granular media.

We study the multiple scattering of short-wavelength ultrasound through the force networks in dry and wet glass bead packings under stress. Over long distance scales, the diffusion approximation is shown to describe adequately the transport of elastic waves dominated by shear waves. The recovered transport mean path reveals a short-range correlation of the force chains. Also we observe the drastic effect of wetting liquids on the energy dissipation in the granular medium. The relevance of these experimental findings for the seismological applications is discussed.

Journal Article↗
PubMed2004

Phase II study of the farnesyl transferase inhibitor R115777 in patients with sensitive relapse small-cell lung cancer.

BACKGROUND: R115777 (tipifarnib, Zarnestra) is a farnesyl transferase inhibitor that blocks the farnesylation of proteins involved in signal transduction pathways critical for cell proliferation and survival. This multicenter phase II study was conducted to determine the efficacy, tolerability and pharmacokinetics of R115777 in patients with relapsed small-cell lung cancer (SCLC). PATIENTS AND METHODS: Patients who had a partial or complete response to their initial chemotherapy regimen, followed by at least 3 months off treatment before relapse (sensitive relapse) were eligible. R115777 was administered in 3-week cycles at a dose of 400 mg orally twice daily for 14 consecutive days followed by 7 days off treatment. RESULTS: Twenty-two patients were enrolled. The median progression-free survival was 1.4 months and median overall survival was 6.8 months. Non-hematological toxicities were predominantly grade 1-2 and included nausea (64%) and fatigue (60%). Grade 3-4 granulocytopenia and thrombocytopenia occurred in 27% and 23% of patients, respectively. Febrile neutropenia was not observed. Pharmacokinetic studies demonstrated peak plasma concentrations of R115777 2.6-4.5 h after oral dosing and no significant drug accumulation. The trial was terminated because no objective responses were observed in 20 patients evaluable for response. CONCLUSIONS: R115777 showed no significant antitumor activity as a single agent in sensitive-relapse SCLC.

Adult↗
PubMed2003

The glass transition time scale and configurational entropy in polymers: an experimental molecular view.

We report direct experimental observation of local conformational dynamics in a polymer chain at the calorimetric glass transition temperature Tg. Variable-temperature two-dimensional (2D) solid-state exchange NMR, at natural abundance, reveals segmental dynamics in pure polyisobutylene (PIB) occurring on a time scale of several seconds over the Tg range observed by DSC (203-208 K). To our knowledge, this is the first direct observation of molecular-level conformer interchange (trans-trans/trans-gauche/gauche-gauche) at the caloric glass transition temperature. Our results provide a chronologically accurate and pedagogically advantageous demonstration of molecular processes during a polymer phase transition, relative to traditional bulk mechanical and calorimetric techniques. More importantly, we use a miscible blend to demonstrate a general strategy for quantitative evaluation of configurational entropy changes via combination of temperature-dependent 2D exchange NMR and Adams-Gibbs theory. Our results on the Tg time scale are directly relevant to fundamental understanding of the Tg length scale, i.e., the dimension of cooperatively rearranging regions.

Journal Article↗
PubMed2002

Experimental and numerical studies of noise-induced coherent patterns in a subexcitable system.

A subexcitable medium of Belousov-Zhabotinsky (BZ) reaction subjected to external Gaussian white noise is studied in experiments and numerical simulations. We observe that at an optimal level of noise the wave sources of excited traveling waves become synchronous, as though there exists a long distance spatial correlation. The synchronous behavior fades if the noise level becomes larger or smaller. Numerical simulations confirm the experimental findings, and point out that the best synchronous behavior takes place when the signal-to-noise ratio of waves becomes largest.

Journal Article↗
PubMed2001

Solution structures and integrin binding activities of an RGD peptide with two isomers.

The Arg-Gly-Asp (RGD) sequence serves as the primary integrin recognition site in extracellular matrix proteins, and peptides containing this sequence can mimic the activities of the matrix proteins. Depending on the context of the RGD sequence, an RGD-containing peptide may bind to all of the RGD-directed integrins, to a few, or to only a single one. We have previously isolated from a phage-displayed peptide library a cyclic peptide that binds avidly to the alpha(v)beta3 and alpha(v)beta5 integrins but does not bind to other closely related integrins. This peptide, ACDCRGDCFCG, exists in two natural configurations depending on internal disulfide bonding. The peptide with the 1-4; 2-3 disulfide bond arrangement accounts for most of the alpha(v) integrin binding activity, whereas the 1-3; 2-4 peptide is about 10-fold less potent. Solution structure analysis by nuclear magnetic resonance reveals an entirely different presentation of the RGD motif in the two isomers of RGD-4C. These results provide new insight into the ligand recognition specificity of integrins.

Bacteriophages↗
PubMed2001

Screening for CRX gene mutations in Chinese patients with Leber congenital amaurosis and mutational phenotype.

PURPOSE: To screen for possible disease-causing mutations in the CRX gene in Chinese patients with Leber congenital amaurosis (LCA) and to enrich the understanding of its mutational phenotype. METHODS: Genomic DNA was collected from 27 patients with LCA. The coding sequences of the CRX gene were analyzed using the PCR-heteroduplex-SSCP method. Mutations were confirmed by DNA sequencing. RESULTS: We identified two heterozygous variations in the CRX gene in two patients with LCA. One was a deletion (GCC-->-CC, A181D1bp) leading to a frameshift and protein truncation. This mutation was present in a patient with LCA, but not in his healthy parents. The ocular manifestations of this A181Delta1bp mutation are described. An intronic variation (IVS1-13G-->C) was found in a patient with LCA as well as in his healthy father. CONCLUSION: A heterozygous A181D1bp mutation in the CRX gene caused an LCA phenotype in a Chinese patient.

Asian People↗
PubMed2001

Effects of green tea on colonic aberrant crypt foci and proliferative indexes in rats.

The present study was designed to investigate the effect of green tea on 1,2-dimethylhydrazine (DMH)-induced aberrant crypt foci (ACF) formation in Wistar rats. Forty-five male weanling Wistar rats were randomly divided into three groups. Rats in Group 1 were injected with DMH (20 mg/kg s.c.) once a week for 10 weeks. Animals in Group 2 received 2% green tea water extract as the sole source of drinking fluid in addition to the same treatment used for Group 1. Group 3 was the negative control group. Animals were killed at the end of Week 16 after the first DMH treatment. ACF were formed in animals in their DMH-treated groups at the end of Week 16. Group 2 had fewer ACF than Group 1. Compared with the positive control group, proliferating cell nuclear antigen labeling index, silver-stained nucleolar organizer regions, and ras-p21 expression were significantly reduced in Group 2. It was concluded that green tea drinking inhibited ACF formation in rats, and such effects may be related to the suppression of cell proliferation in the intestinal crypts.

1,2-Dimethylhydrazine↗
PubMed2001

New rice mutants lacking glutelin alpha-1 subunit.

Four rice (Oryza sativa L.) mutant lines lacking glutelin alpha-1 subunit were obtained by screening the progenies of fertilized egg treatment with MNU. SDS-PAGE and IEF analyses showed that the mutants without pI6.82 polypeptide in common while forming/increasing other polypeptide indicating that the mutants were controlled by structural genes. IEF analysis also suggested that the polypeptides of pI6.82 and pI8.58 derived from the same glutelin precursor. The mutants are considered to be useful material for glutelin quality improvement and for genetic regulatory mechanism study of glutelin biosynthesis.

Glutens↗
PubMed2001

[Study on the relationship between methylenetetrahydrofolate reductase gene C677T mutation and coronary heart disease].

OBJECTIVE: To investigate whether methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism is linked with coronary heart disease (CHD). METHODS: Transmission/disequilibrium test(TDT), sib transmission/disequilibrium test(STDT), and sibship disequilibrium test(SDT) were used. Forty-five CHD pedigrees with at least one CHD patient in the first degree relatives of probands were recruited from Oct. 1998 to Feb. 1999. Among those recruited were 21, 2 and 22 pedigrees with the genotypes of both parents known, one parental genotype unknown and both unknown, respectively. MTHFR genotype was measured by PCR-RFLP technique. RESULTS: Neither the TDT for 23 nuclear families with at least one parental genotype known or the STDT and SDT for 40 sibships found significant difference between the transmitted and untransmitted MTHFR gene 677T allele distributions. CONCLUSION: The above results suggest that MTHFR gene 677T allele is probably not linked with CHD in Chinese population.

Coronary Disease↗
PubMed2001

[Comparison and analysis of clinicopathology of lung cancer between 1980s and 1990s in the Shenyang area (1,224 cases)].

OBJECTIVE: To compare the changes in pathogenetis and histopathology of lung cancer between 1980s and 1990s in the Shenyang area. METHODS: The HE stained sections of 572 cases of lung cancer from 1981-1990 and 652 cases from 1991-2000 were reviewed. Parts of these samples were also studied with immunohistochemistry and in situ hybridization. RESULTS AND CONCLUSIONS: By comparing the finding in the 1980s and those of the 1990s, it was found that (1) the incidence of lung cancer in women increased. (2) the highest incidence occurred in the 61 to 70 year of old group in 1990s, in 1980s it was 51-60 years. (3) there was an increased incidence of adenocarcinoma, especially papillary adenocarcinoma and acinar adenocarcinoma and bronchioloalveolar carcinoma in the 1990s.

Adult↗
PubMed2001

[Penetrance of Leber hereditary optic neuropathy in Chinese individuals with mitochondrial DNA 11778 mutation].

OBJECTIVE: To analyze the penetrance of Leber hereditary optic neuropathy (LHON) in families with homoplasmic mitochondrial DNA (mtDNA) 11778 mutation. METHODS: Maternal relatives of 16 families were analyzed based on ocular phenotype and primary mtDNA mutation analysis. RESULTS: One hundred and thirty individuals from the 16 families harbored the 11778 mutation. Of the 130 individuals, 65 were male and 65 female. Forty-three individuals (34 male and 9 female) were affected with LHON. The penetrance of LHON in the 16 families ranged from 13.3% to 66.7%, with an average penetrance of 33.1%. Males, with an average penetrance of 52.3%, were more affected than females who had an average penetrance of 13.8%. About 79% of the affected individuals were male with a male to female ratio of 3.8: 1. The number of affected females found in the families analysis is greater than that in the probands analysis where only 3 of 41 probands with LHON and mtDNA11778 mutation were female(male to female ratio =12.7:1). CONCLUSION: The penetrance of LHON in Chinese individuals with homoplasmic mtDNA11778 mutation is about one third,which is within the range of that in Caucasion.

DNA Mutational Analysis↗
PubMed2001

[Different serum lipid adjustment drugs for the treatment of hyperlipidemic fatty liver].

OBJECTIVE: To research the effect of different serum lipid adjustment drugs, Simvastatin and Fenofibrate, on hyperlipidemic fatty liver. METHODS: The rat models of hyperlipidemic fatty liver induced by high fat diet were treated with Fenofibrate and Simvastatin respectively to investigate the change of the liver index, liver function, the serum and liver lipid, MDA, and pathologic histology. RESULTS: The liver index and the content of triglyceride (TC1.80 +/-0.20/2.10+/-0.33), total cholesterol (TG 0.76+/-0.18/1.09+/-0.31), MDA both in the serum and the liver in the model group were significantly higher than those in control group. Slight or moderate hepatic steatosis was observed in model group. Fenofibrate decreased serum triglyceride, total cholesterol, and MDA both in serum and liver significantly, but increased the ALT, ALP, liver index, liver lipids, and finally leading to severe hepatic steatosis. Simvastatin lowered the level of lipid and MDA both in serum and liver, and liver histology was improved nearly to normal. Moreover, little side effect on the liver was observed. CONCLUSIONS: Simvastatin can be applied for prevention and treatment of hyperlipidemic fatty liver safely and effectively, while Fenofibrate can not.

Animals↗
PubMed2001

[Studies on the inhibitory effects of tea polyphenols and tea pigments on liver precancerous lesion in rats].

The chemopreventive effects of tea polyphenols and tea pigments on liver precancerous lesion in rats were investigated. The results showed that the density and area of GST-P in the tea-treated groups were significantly reduced as compared with the positive control group. Furthermore, tea polyphenols and tea pigments induced the expression of p21WAF1 protein, inhibited the expression of Bcl-2 protein and induced the expression of Bax protein. It is concluded that GST-P was significantly inhibited by tea polyphenols and tea pigments and inhibition of cell proliferation and induction of apoptosis may be the two important mechanisms.

Animals↗