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Biomedical subjects

X Hu

Publications and source records attributed to X Hu.

At least 19 recordsLinked to original sources
PubMed2007

Determinants of childhood overweight and obesity in China.

In order to investigate the determinants of childhood overweight and obesity in China, the prevalence of overweight (including obesity) was compared according to different dietary and physical activity patterns and parental body weight status. A total of 6826 children aged 7-17 years from the 2002 China National Nutrition and Health Survey were included in the study. Information for dietary intake was collected using three consecutive 24-h recalls by trained interviewers. The amounts of cooking oil and condiments consumed were weighed. An interview-administered 1-year physical activity questionnaire was used to collect physical activity information. The results showed that the heavier the parental bodyweight, the higher the overweight prevalence in children. The prevalence ratio increased if parent(s) were overweight and/or obese, up to 12.2 if both parents were obese. Overweight children consumed significantly more dietary energy, protein and fat, but less carbohydrate than their normal weight counterparts. On average, overweight children spent 0.5 h less on moderate/vigorous activities and 2.3 h more on low intensity activities per week. The following prevalence ratios were statistically significant: walking to and from school (0.6); moderate/vigorous activities > or =45 min/d (0.8); low intensity physical activities >2 h/d (1.3); the consumption of > or =25 g/d cooking oil (1.4); > or =200 g/d meat and meat products consumption (1.5); > or =100g/d dairy products (1.8). After adjustment for parental body weight status and socioeconomic status, only cooking oil consumption and walking to and from school remained significantly related to child overweight. In conclusion, parental weight status is an import-ant determinant. Fat intake, low intensity activities and active transport to/from school may be suitable entry points for overweight prevention among Chinese school children.

Body Weight↗
PubMed2006

The 620W allele is the PTPN22 genetic variant conferring susceptibility to RA in a Dutch population.

OBJECTIVES: A missense SNP, C1858T, in PTPN22 has been identified as a genetic risk factor for rheumatoid arthritis (RA). Subsequent work has suggested that other variants in this gene, in particular a haplotype marked by the minor allele of rs3789604, are associated with RA in white North Americans independent of C1858T. We tested this hypothesis in an independent white Dutch study. METHODS: A total of 667 RA patients and 286 controls were genotyped for 13 PTPN22 single nucleotide polymorphisms (SNPs) by allele-specific kinetic polymerase chain reaction. rs3789604 was genotyped in an additional 410 RA and 270 UA patients participating in the Leiden early arthritis inception cohort. We conducted single-marker and haplotype association tests. RESULTS: The sole haplotype strongly associated with RA in our Dutch population carries the PTPN22 1858T allele. A second haplotype identical at all other SNPs tested except 1858 was not associated with disease. No significant association of the haplotype tagged by the 3' PTPN22 SNP, rs3789604, with RA susceptibility (P = 0.134) was observed in our sample set. CONCLUSION: We conclude that C1858T is the sole PTPN22 variant predisposing to RA in our white Dutch sample set.

Adult↗
PubMed2006

Exosomal Fetuin-A identified by proteomics: a novel urinary biomarker for detecting acute kidney injury.

Urinary exosomes containing apical membrane and intracellular fluid are normally secreted into the urine from all nephron segments, and may carry protein markers of renal dysfunction and structural injury. We aimed to discover biomarkers in urinary exosomes to detect acute kidney injury (AKI), which has a high mortality and morbidity. Animals were injected with cisplatin. Urinary exosomes were isolated by differential centrifugation. Protein changes were evaluated by two-dimensional difference in gel electrophoresis and changed proteins were identified by mass spectrometry. The identified candidate biomarkers were validated by Western blotting in individual urine samples from rats subjected to cisplatin injection; bilateral ischemia and reperfusion (I/R); volume depletion; and intensive care unit (ICU) patients with and without AKI. We identified 18 proteins that were increased and nine proteins that were decreased 8 h after cisplatin injection. Most of the candidates could not be validated by Western blotting. However, exosomal Fetuin-A increased 52.5-fold at day 2 (1 day before serum creatinine increase and tubule damage) and remained elevated 51.5-fold at day 5 (peak renal injury) after cisplatin injection. By immunoelectron microscopy and elution studies, Fetuin-A was located inside urinary exosomes. Urinary Fetuin-A was increased 31.6-fold in the early phase (2-8 h) of I/R, but not in prerenal azotemia. Urinary exosomal Fetuin-A also increased in three ICU patients with AKI compared to the patients without AKI. We conclude that (1) proteomic analysis of urinary exosomes can provide biomarker candidates for the diagnosis of AKI and (2) urinary Fetuin-A might be a predictive biomarker of structural renal injury.

Acute Kidney Injury↗
PubMed2006

Thin-section CT of the lungs: eye-tracking analysis of the visual approach to reading tiled and stacked display formats.

OBJECTIVE: To use eye-tracking analysis to identify the differences in approach to and efficiency of reading thin-section CT of the lungs presented tiled and stacked soft-copy displays. MATERIALS AND METHODS: Four chest radiologists read 16 thin-section CT examinations displayed in either a tiled (four images at once) or stacked (full screen cine) format. Eye-movements were recorded and analysed in terms of movement type; saccade distance (classified by the calculated range of useful peripheral vision), number of fixations, duration and direction of gaze-comparison of the areas of the images viewed. RESULTS: Cases presented in stacked format were read quicker than when presented in tiled format with a greater fixation frequency (5 fixations versus 4.5 fixations points per 100 data points; p<0.001) and a greater proportion of short saccades (97% versus 94%; p<0.005). The consistency with which the observers viewed equivalent areas of the scan images in different cases was greater when viewing in stacked format (mean kappa 0.45 versus 0.36; p<0.05) suggesting a more systematic approach to reading. CONCLUSION: Eye-tracking data demonstrates why thin-section CT examinations of the lungs are read more efficiently when displayed in a stack as opposed to a tiled format.

Data Display↗
PubMed2006

Biomarker and drug-target discovery using proteomics in a new rat model of sepsis-induced acute renal failure.

Sepsis is one of the common causes of acute renal failure (ARF). The objective of this study was to identify new biomarkers and therapeutic targets. We present a new rat model of sepsis-induced ARF based on cecal ligation and puncture (CLP). We used this model to find urinary proteins which may be potential biomarkers and/or drug targets. Aged rats were treated with fluids and antibiotics after CLP. Urinary proteins from septic rats without ARF and urinary proteins from septic rats with ARF were compared by difference in-gel electrophoresis (DIGE). CLP surgery elevated interleukin (IL)-6 and IL-10 serum cytokines and blood nitrite compared with sham-operated rats. However, there was a range of serum creatinine values at 24 h (0.4-2.3 mg/dl) and only 24% developed ARF. Histology confirmed renal injury in these rats. Forty-nine percent of rats did not develop ARF. Rats without ARF also had less liver injury. The mortality rate at 24 h was 27% but was increased by housing the post-surgery rats in metabolic cages. Creatinine clearance and urine output 2-8 h after CLP was significantly reduced in rats which died within 24 h. Using DIGE we identified changes in a number of urinary proteins including albumin, brush-border enzymes (e.g., meprin-1-alpha) and serine protease inhibitors. The meprin-1-alpha inhibitor actinonin prevented ARF in aged mice. In summary, we describe a new rat model of sepsis-induced ARF which has a heterogeneous response similar to humans. This model allowed us to use DIGE to find changes in urinary proteins and this approach identified a potential biomarker and drug target - meprin-1-alpha.

Acute Kidney Injury↗
PubMed2006

Reticulon proteins: emerging players in neurodegenerative diseases.

Reticulons (RTNs) are a group of integral membrane proteins that have a uniquely conserved C-terminal domain named RHD. In mammalian genomes, transcripts are produced from four genes, rtn1 to rtn4, under the regulation of tissue or cell-type-specific expression. The presence of alternative promoters for gene expression and multiple cryptic splicing sites have resulted in large numbers of genes/proteins that are classified among the reticulon family. Although this family exists in almost all eukaryotes, only the rtn4 gene product, Nogo (RTN4), has gained relatively more in-depth attention. Despite predominant localization in the endoplasmic reticulum, Nogo on the cell surface appears to play a critical role as an inhibitory molecule for axonal growth and regeneration in humans and rodents. Recently, studies have expanded the biological functions of RTNs to other facets including modulating the enzymatic activity of beta-secretase in Alzheimer's disease. In this review, we summarize the accumulated findings concerning the structural and functional aspects of RTNs and speculate on their linkage to the pathogenesis of neurodegenerative diseases.

Animals↗
PubMed2006

Molecular mechanisms of spider silk.

Spiders spin high-performance silks through the expression and assembly of tissue-restricted fibroin proteins. Spider silks are composite protein biopolymers that have complex microstructures. Retrieval of cDNAs and genomic DNAs encoding silk fibroins has revealed an association between the protein sequences and structure-property relationships. However, before spider silks can be subject to genetic engineering for commercial applications, the complete protein sequences and their functions, as well as the details of the spinning mechanism, will require additional progress and collaborative efforts in the areas of biochemistry, molecular biology and material science. Novel approaches to reveal additional molecular constituents embedded in the spider fibers, as well as cloning strategies to manipulate the genes for expression, will continue to be important aspects of spider biology research. Here we summarize the molecular characteristics of the different spider fibroins, the mechanical properties and assembly process of spidroins and the advances in protein expression systems used for recombinant silk production. We also highlight different technical approaches being used to elucidate the molecular constituents of silk fibers.

Amino Acid Motifs↗
PubMed2006

Sepsis-induced organ failure is mediated by different pathways in the kidney and liver: acute renal failure is dependent on MyD88 but not renal cell apoptosis.

Toll-like receptors (TLRs) are important in sepsis. Myeloid differentiation factor 88 (MyD88) is a key molecule involved in signal transduction by multiple TLRs. The objective of this study was to investigate the contribution of TLR4 and MyD88 to acute renal failure (ARF) induced by polymicrobial sepsis. Liver dysfunction and apoptosis in the spleen contribute to sepsis severity after cecal ligation and puncture (CLP). Therefore, we also investigated liver injury and splenic apoptosis. We used a mouse model of sepsis-induced ARF using CLP to generate polymicrobial sepsis. Despite fluid and antibiotic resuscitation the mice developed multi-organ failure, including ARF, which resembles human sepsis. We investigated the role of the TLR4 receptor by comparing C3H/HeJ mice (which lack TLR4) with C3H/He0UJ normal controls. The role of MyD88 was investigated by comparing MyD88 knockout mice (MyD88(-/-)) with wild-type controls. Following CLP, mice lacking TLR4 and wild-type mice both developed comparable ARF. However, MyD88(-/-) mice did not develop ARF compared to wild-type controls. In contrast, MyD88(-/-) mice developed liver injury comparable to wild type. After CLP, MyD88(-/-) mice had significantly reduced apoptosis in the spleen compared with wild type. Apoptosis was not detected in the kidney of wild-type or MyD88(-/-) mice after CLP. In summary, ARF induced by polymicrobial sepsis is dependent on MyD88, but not TLR4. The absence of MyD88 dissociates ARF from liver injury; liver injury is MyD88-independent. There was MyD88-dependent apoptosis in the spleen, but no apoptosis in the kidney. MyD88 may be a good drug target for some, but not all, organ dysfunctions following sepsis.

Acute Kidney Injury↗
PubMed2006

Simvastatin improves sepsis-induced mortality and acute kidney injury via renal vascular effects.

Acute kidney injury (AKI) occurs in about half of patients in septic shock and the mortality of AKI with sepsis is extremely high. An effective therapeutic intervention is urgently required. Statins are 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors that also have pleiotropic actions. They have been reported to increase the survival of septic or infectious patients. But the effect of simvastatin, a widely used statin, on sepsis-induced AKI is unknown. The effects of simvastatin and tumor necrosis factor (TNF)-alpha neutralizing antibody were studied in a clinically relevant model of sepsis-induced AKI using cecal ligation and puncture (CLP) in elderly mice. Simvastatin significantly improved CLP-induced mortality and AKI. Simvastatin attenuated CLP-induced tubular damage and reversed CLP-induced reduction of intrarenal microvascular perfusion and renal tubular hypoxia at 24 h. Simvastatin also restored towards normal CLP-induced renal vascular protein leak and serum TNF-alpha. Neither delayed simvastatin therapy nor TNF-alpha neutralizing antibody improved CLP-induced AKI. Simvastatin improved sepsis-induced AKI by direct effects on the renal vasculature, reversal of tubular hypoxia, and had a systemic anti-inflammatory effect.

Acute Kidney Injury↗
PubMed2006

Induction of micronuclei in human fibroblasts across the Bragg curve of energetic heavy ions.

The space environment consists of a varying field of radiation particles including high-energy ions, with spacecraft shielding material providing the major protection to astronauts from harmful exposure. Unlike low-LEpsilonTau gamma or X rays, the presence of shielding does not always reduce the radiation risks for energetic charged-particle exposure. The dose delivered by the charged particle increases sharply as the particle approaches the end of its range, a position known as the Bragg peak. However, the Bragg curve does not necessarily represent the biological damage along the particle path since biological effects are influenced by the track structures of both primary and secondary particles. Therefore, the "biological Bragg curve" is dependent on the energy and the type of the primary particle and may vary for different biological end points. Here we report measurements of the biological response across the Bragg curve in human fibroblasts exposed to energetic silicon and iron ions in vitro at two different energies, 300 MeV/nucleon and 1 GeV/nucleon. A quantitative biological response curve generated for micronuclei per binucleated cell across the Bragg curve did not reveal an increased yield of micronuclei at the location of the Bragg peak. However, the ratio of mono- to binucleated cells, which indicates inhibition of cell progression, increased at the Bragg peak location. These results confirm the hypothesis that severely damaged cells at the Bragg peak are more likely to go through reproductive death and not be evaluated for micronuclei.

Cell Line↗
PubMed2006

Separation of THF and water by room temperature ionic liquids.

Liquid-liquid equilibrium data are presented for mixtures of 1-(2-hydroxyethyl)-3-methylimidazolium chloride or tetrafluoroborate + tetrahydrofuran(THF) + water at 293.15 K. The data presented provides a valuable insight into how the environmentally friendly ionic liquid solvent can have the separation power of THF-water azeotropic systems. The sloping of the tie lines towards the THF vertex is investigated for mixtures of 1-(2-hydroxyethyl)-3-methylimidazolium chloride (or tetrafluoroborate) + THF + water. Selectivity values, derived from the tie line data, indicate that these two ionic liquids are suitable solvents for the liquid-liquid extraction of water from THF.

Borates↗
PubMed2005

Dynamic changes in orbitofrontal neuronal activity in rats during opiate administration and withdrawal.

The orbitofrontal cortex is involved in the reinforcing effects of drugs of abuse. However, how the dynamic activity in OFC changes during opiate administration and withdrawal period has not been investigated. We first tested the effects of opiates and drug craving with the conditioned place preference paradigm, using manganese-enhanced magnetic resonance imaging and traditional electroencephalograph recording techniques in rats. T1-weighted 2D MRI (4.7 T) was used after unilateral injection of MnCl(2) (200 nL, 80 mM) into the right orbitofrontal cortex. The manganese-enhanced magnetic resonance imaging data suggested that the OFC activity decreased during the opiate administration period but recovered increasingly during the withdrawal period. Also, we found decreases and increases in gamma-band (20-100 Hz) activity during the opiate administration and withdrawal period, respectively. Our results showed that orbitofrontal cortex activity decreased during morphine administration and then went up progressively over several days during withdrawal. The time course of the recovery of orbitofrontal activity from inhibition during the withdrawal period may be related to the experience of drug craving.

Animals↗
PubMed2005

Steinernema akhursti sp. n. (Nematoda: Steinernematidae) from Yunnan, China.

A new species of entomopathogenic nematode, herein described as Steinernema akhursti sp. n., was recovered from soil samples collected from Yunnan Province, the People's Republic of China. Both morphological and molecular data show congruently that S. akhursti sp. n. belongs to the Steinernema feltiae group. It can be separated from all described Steinernema species by the combined morphological and morphometrical characters of various stages of the nematodes. For the first generation male, the new species can be recognized by spicule length 90 +/- 4.6 microm, spicule tip blunt with an aperture on the ventral side, gubernaculum with a long and needle-shaped cuneus, and tail conoid with a prominent mucron on the tip and a concave on ventral side. For the infective juvenile, the combination of the following characters: body length 812 +/- 19 microm, distance from anterior end to excretory pore 59 +/- 1.5 microm, tail length 73 +/- 2.9 microm, E% 77 +/- 4.5, lateral field with six evenly distributed and identical ridges at the middle body portion, and tail with long and slightly constrict hyaline portion can be used to separate the new species from other nematodes. For the female, the new species is characterized by: tail conoid with a short mucron and slightly swelling anal portion and a symmetrical, slightly protruding vulva with conspicuous double-flapped epiptygma. The nematode can be separated from other described species of Steinernema by DNA sequences of either a partial 28S rDNA or the internal transcribed spacer regions of rDNA and from the closely related species S. feltiae and Steinernema oregonense by cross-breeding tests.

Animals↗
PubMed2005

Identification of a tobacco protein interacting with tomato mosaic virus coat protein and facilitating long-distance movement of virus.

The protein-protein interaction of virus and host is essential for virus infection and host defense. The coat protein (CP) of tomato mosaic virus (ToMV) has been proved to be involved in cell-to-cell and long-distance movements of viruses that are presumably related with the protein-protein interactions. However, the host proteins that interact with the ToMV coat protein (ToCP) are largely unknown. In this study, we isolated a cDNA from a tobacco library through yeast two-hybrid system, which encodes a protein designated the ToMV CP-interacting protein-L (IP-L) that interacted with ToCP in vitro and in vivo. Sequencing analysis revealed that the putative coding region of IP-L gene was identical to that of an 'elicitor responsive protein' gene from N. tabacum (Genbank: #AB040409). A homology was also found between the cDNA sequence of IP-L and two senescence-related cDNAs (SENU1: Z75523 and AY479987) isolated from tomato and pepper. Northern blotting analysis showed that the mRNA level of IP-L was elevated after infection of ToMV. Then, we investigated the in vivo function of IP-L using virus-induced gene silencing (VIGS) and virus challenging assay. Semi-quantitative RT-PCR and Northern blotting results showed that the endogenous mRNA of IP-L in N. benthamiana plant was silenced at 10 days post inoculation with the in vitro transcripts of PVX-IP-L that were produced from the potato virus X (PVX)-based gene silencing plasmid pPC2S.IP-L. The IP-L silent plant developed a delayed systemic symptom at 7 days post challenging with ToMV, indicating that a high expression of IP-L was necessary for the interaction with ToCP to assist the viral transportation. Together, our data suggested that IP-L is a novel plant factor that interacts with the coat protein of ToMV and facilitates the long-distance movement of virus, which may provide a valuable clue for us to further investigate the mechanisms of plant virus infection and to control plant virus diseases.

Amino Acid Sequence↗
PubMed2005

Identifying potential risk haplotypes for schizophrenia at the DTNBP1 locus in Han Chinese and Scottish populations.

The dystrobrevin-binding protein 1 (DTNBP1) gene on chromosome 6p has emerged as a potential susceptibility gene for schizophrenia. Although a number of attempts to replicate the original association finding have been successful, they have not identified any obvious pathogenic variants or a single at risk haplotype common to all populations studied. In the present study we attempted further replication in an independent sample of 638 nuclear families from the Han Chinese population of Sichuan Province, SW China. We also examined 580 Scottish schizophrenic cases and 620 controls. We genotyped 10 single-nucleotide polymorphisms (SNPs) in DTNBP1 that were used in the original report of association, plus rs2619538 (SNP 'A') in the putative promoter region, which has also been associated with schizophrenia. In the Chinese trios we found that two SNPs (P1635 and P1765) were significantly overtransmitted, but with alleles opposite to those reported in the original studies. SNPs P1757 and P1765 formed a common haplotype, which also showed significant overtransmission. In the Scottish cases and controls, no individual markers were significantly associated with schizophrenia. A single haplotype, which included rs2619538 and P1583, and one rare haplotype, composed of P1320 and P1757, were significantly associated with schizophrenia, but no previously reported haplotypes were associated. Based on the data from the Chinese population, our results provide statistical support for DTNBP1 as a susceptibility gene for schizophrenia, albeit with haplotypes different from those of the original study. However, our lack of replication in the Scottish samples also indicates that caution is warranted when evaluating the robustness of the evidence for DTNBP1 as genetic risk factor for schizophrenia.

Alleles↗
PubMed2005

The phylogeny of Chinese indigenous pig breeds inferred from microsatellite markers.

A genetic study of 32 local Chinese, three foreign pig breeds [Duroc (DU), Landrace and Yorkshire], and two types of wild boar (Hainan and Dongbei wild boar) based on 34 microsatellite loci was carried out to clarify the phylogeny of Chinese indigenous pig breeds. The allele frequencies, effective numbers of alleles, and the average heterozygosity within populations were calculated. The results showed that the genetic variability of the Lingao pig was the largest, while the Jiaxing pig was the lowest. The greatest distance between domestic pigs was found between Shanggao and DU pig and the shortest was found between Wuzhishan and Lingao pig, respectively. A neighbour-joining tree constructed from Modified Cavalli-Sforza genetic distances divided Chinese pigs into two clusters; four subclusters were also identified. Our results only partly agree with the traditional types of classification and also provide a new relationship among Chinese local pig breeds. Our data also confirmed that Chinese pig breeds have a different origin from European/American breeds and can be utilized in programmes that aim to maintain Chinese indigenous pig breeds.

Alleles↗
PubMed2005

Quality of life for people with intellectual disabilities in China: a cross-culture perspectives study.

BACKGROUND: The concept of quality of life (QOL) is explained on the basis of traditional Chinese culture and contemporary social and cultural trends. METHOD: The importance of internationally recognized QOL domains and indicators was determined for three respondent groups: consumers, parents of the consumers, and teachers and rehabilitation professionals working with the clients. RESULTS: Principal component analysis confirmed seven factors influencing QOL for people with intellectual disabilities (ID) in China. These seven components are conceptually equivalent to the eight domains found in the international QOL literature. CONCLUSION: The concept of QOL has become one of the most sensitive issues in present Chinese society and peoples' lives, and an important theoretical framework for the education and rehabilitation for people with ID in several ways: curriculum development, service delivery models, education and rehabilitation practices, and employment models.

Adult↗