Biomedical subjects

Yulan Wang

Publications and source records attributed to Yulan Wang.

15 recordsLinked to original sources

PubMed2006

Metabolome, transcriptome, and bioinformatic cis-element analyses point to HNF-4 as a central regulator of gene expression during enterocyte differentiation.

DNA-binding transcription factors bind to promoters that carry their binding sites. Transcription factors therefore function as nodes in gene regulatory networks. In the present work we used a bioinformatic approach to search for transcription factors that might function as nodes in gene regulatory networks during the differentiation of the small intestinal epithelial cell. In addition we have searched for connections between transcription factors and the villus metabolome. Transcriptome data were generated from mouse small intestinal villus, crypt, and fetal intestinal epithelial cells. Metabolome data were generated from crypt and villus cells. Our results show that genes that are upregulated during fetal to adult and crypt to villus differentiation have an overrepresentation of potential hepatocyte nuclear factor (HNF)-4 binding sites in their promoters. Moreover, metabolome analyses by magic angle spinning (1)H nuclear magnetic resonance spectroscopy showed that the villus epithelial cells contain higher concentrations of lipid carbon chains than the crypt cells. These findings suggest a model where the HNF-4 transcription factor influences the villus metabolome by regulating genes that are involved in lipid metabolism. Our approach also identifies transcription factors of importance for crypt functions such as DNA replication (E2F) and stem cell maintenance (c-Myc).

Algorithms↗

PubMed2006

Experimental metabonomic model of dietary variation and stress interactions.

Stress in the form of moderate periods of maternal separation of newborn rats has been postulated to cause permanent changes in the central nervous system and diseases in later life. It is also considered that dietary supplementation with long chain polyunsaturated fatty acids (LC-PUFAs) can potentially ameliorate the effects of stress. The metabolic consequences of early life maternal separation stress were investigated in rats (2-14 days after birth), either alone or in combination with secondary acute water avoidance stress at 3-4 months of age. The effect of a LC-PUFA-enriched dietary intervention in stressed animals was also assessed. Systematic changes in metabolic biochemistry were evaluated using 1H nuclear magnetic resonance spectroscopy of blood plasma and multivariate pattern recognition techniques. The biochemical response to stress was characterized by decreased levels of total lipoproteins and increased levels of amino acids, glucose, lactate, creatine, and citrate. Secondary acute water avoidance stress also caused elevated levels of O-acetyl glycoproteins in blood plasma. LC-PUFAs dietary enrichment did not alter the metabolic response to stress, but did result in a modified lipoprotein profile. This work indicates that the different stressor types resulted in some common systemic metabolic responses that involve changes in energy and muscle metabolism, but that they are not reversible by dietary intervention.

Amino Acids↗

PubMed2006

Transgenomic metabolic interactions in a mouse disease model: interactions of Trichinella spiralis infection with dietary Lactobacillus paracasei supplementation.

Irritable Bowel Syndrome (IBS) is a common multifactorial intestinal disorder for which the aetiology remains largely undefined. Here, we have used a Trichinella spiralis (T. spiralis)-induced model of post-infective IBS, and the effects of probiotic bacteria on gut dysfunction have been investigated using a metabonomic strategy. A total of 44 mice were divided into four groups: an uninfected control group and three T. spiralis-infected groups, one as infected control and the two other groups subsequently treated with either Lactobacillus paracasei (L. paracasei) NCC2461 in spent culture medium (SCM) or with L. paracasei-free SCM. Plasma, jejunal wall and longitudinal myenteric muscle samples were collected at day 21 post-infection. An NMR-based metabonomic approach characterized that the plasma metabolic profile of T. spiralis-infected mice showed an increased energy metabolism (lactate, citrate, alanine), fat mobilization (acetoacetate, 3-D-hydroxybutyrate, lipoproteins) and a disruption of amino acid metabolism due to increased protein breakdown, which were related to the intestinal hypercontractility. Increased levels of taurine, creatine and glycerophosphorylcholine in the jejunal muscles were associated with the muscular hypertrophy and disrupted jejunal functions. L. paracasei treatment normalized the muscular activity and the disturbed energy metabolism as evidenced by decreased glycogenesis and elevated lipid breakdown in comparison with untreated T. spiralis-infected mice. Changes in the levels of plasma metabolites (glutamine, lysine, methionine) that might relate to a modulation of immunological responses were also observed in the presence of the probiotic treatment. The work presented here suggests that probiotics may be beneficial in patients with IBS.

Amino Acids↗

PubMed2006

The assessment of plant metabolite profiles by NMR-based methodologies.

NMR-based metabolic profiling techniques can simultaneously track changes in many plant metabolites and have found a number of applications in both systems biology and biosafety. Together with multivariate statistical analyses, NMR spectroscopy has been successfully applied to the characterisation of various herbs and plant products for quality control, authentication, determining geographical origin and for detecting adulteration of products. Additionally, the metabolic consequences of plant extracts have been demonstrated in experimental animals and in man using NMR-based metabonomics approaches to characterise the response. Here the application of NMR spectroscopy and chemometric tools for analysing plant-based products and their metabolic consequences are considered with particular emphasis on deconvolving biological complexity and minimising confounding biological variability with analytical 'noise'.

Animals↗

PubMed2005

System level metabolic effects of a Schistosoma japonicum infection in the Syrian hamster.

A metabolic profiling strategy was used to investigate the metabolic responses of Syrian hamsters (SLAC) to a Schistosoma japonicum infection using high resolution 1H nuclear magnetic resonance (NMR) spectroscopy and pattern recognition. In two independent experiments, male hamsters were each infected with 100 S. japonicum cercariae. At days 34-36 post-infection, urine was obtained from hamsters housed individually in metabolism cages. At the same time, urine was collected from age- and sex-matched infection-free control hamsters. The main biochemical effects of a S. japonicum infection in the hamster consisted of reduced levels of urinary tricarboxylic acid cycle intermediates, including citrate and succinate and increased levels of pyruvate. In addition, a range of microbial-related metabolites, such as hippurate, p-cresol glucuronide, phenylacetylglycine and trimethylamine were also associated with a S. japonicum infection. Most of the observed biochemical effects were in common with those previously characterized for a S. mansoni infection in a mouse host. The major distinguishing consequence of a S. japonicum infection in the hamster was the inhibition of manufacture or utilization of short-chain fatty acids, when compared to a S. mansoni infection in the mouse.

Animals↗

PubMed2005

Exploration of the direct metabolic effects of mercury II chloride on the kidney of Sprague-Dawley rats using high-resolution magic angle spinning 1H NMR spectroscopy of intact tissue and pattern recognition.

Mercury II chloride (HgCl2) toxicity was investigated in Sprague-Dawley rats using high-resolution magic angle spinning (HRMAS) 1H NMR spectroscopy in conjunction with principal component analysis (PCA). Intact renal cortex and papilla samples from Sprague-Dawley rats treated with HgCl2 at two dose levels (0.5 and 2 mg/kg) and from matched controls (n=5 per group) were assessed at 48 h p.d. HgCl2) caused depletion of renal osmolytes such as glycerophosphocholine (GPC), betaine, trimethylamine N-oxide (TMAO), myo-inositol and taurine in both the renal cortex and the papilla. In addition, relatively higher concentrations of valine, isobutyrate, threonine and glutamate were observed in HgCl2-treated rats, particularly in the renal cortex, which may reflect a counterbalance response to the observed loss of other classes of renal osmolytes. Increased levels of glutamate were present in the cortex of treated rats, which may be associated with HgCl2-induced renal acidosis and disruption of the tricarboxylic acid cycle. A dose response was observed in both cortical and papillary tissue with increasing severity of metabolic disruption in the high dose group. 1H HRMAS NMR profiles of individual animals correlated well with conventional clinical chemistry and histology confirming the reproducibility of the technology and generating complementary molecular pathway information.

Amino Acids↗

PubMed2005

A metabonomic strategy for the detection of the metabolic effects of chamomile (Matricaria recutita L.) ingestion.

A metabonomic strategy, utilizing high-resolution 1H NMR spectroscopy in conjunction with chemometric methods (discriminant analysis with orthogonal signal correction), has been applied to the study of human biological responses to chamomile tea ingestion. Daily urine samples were collected from volunteers during a 6-week period incorporating a 2-week baseline period, 2 weeks of daily chamomile tea ingestion, and a 2-week post-treatment phase. Although strong intersubject variation in metabolite profiles was observed, clear differentiation between the samples obtained before and after chamomile ingestion was achieved on the basis of increased urinary excretion of hippurate and glycine with depleted creatinine concentration. Samples obtained up to 2 weeks after daily chamomile intake formed an isolated cluster in the discriminant analysis map, from which it was inferred that the metabolic effects of chamomile ingestion were prolonged during the 2-week postdosing period. This study highlights the potential for metabonomic technology in the assessment of nutritional interventions, despite the high degree of variation from genetic and environmental sources.

Beverages↗

PubMed2004

Metabonomic investigations in mice infected with Schistosoma mansoni: an approach for biomarker identification.

Schistosomiasis, a chronic and debilitating parasitic disease, affects approximately 200 million people in the developing world and imposes a substantial public health and economic impact. Accurately diagnosing at the individual level, monitoring disease progression, and assessing the impact of pharmacological interventions at the population level are of prime importance for controlling schistosomiasis. Using a Schistosoma mansoni-mouse model, we present a characterization of a parasitic infection by metabolic profiling, employing (1)H NMR spectroscopy and multivariate pattern recognition techniques. We infected 10 mice with 80 S. mansoni cercariae each and collected urine samples 49 and 56 days postinfection. Urine samples were also obtained from 10 uninfected control mice at the same time. The metabolic signature of an S. mansoni infection consists of reduced levels of the tricarboxylic acid cycle intermediates, including citrate, succinate, and 2-oxoglutarate, and increased levels of pyruvate, suggesting stimulated glycolysis. A disturbance of amino acid metabolism was also associated with an S. mansoni infection, as indicated by depletion of taurine, 2-oxoisocaproate, and 2-oxoisovalerate and elevation of tryptophan in the urine. A range of microbial-related metabolites, i.e., trimethylamine, phenylacetylglycine, acetate, p-cresol glucuronide, butyrate, propionate, and hippurate, were also coupled with an S. mansoni infection, indicating disturbances in the gut microbiota. Our work highlights the potential of metabolic profiling to enhance our understanding of biological responses to parasitic infections. It also holds promise as a basis for novel diagnostic tests with high sensitivity and specificity and for improved disease surveillance and control.

Animals↗

PubMed2004

Multiple parasite infections and their relationship to self-reported morbidity in a community of rural Côte d'Ivoire.

BACKGROUND: Concomitant parasitic infections are common in the developing world, yet most studies focus on a single parasite in a narrow age group. We investigated the extent of polyparasitism and parasite associations, and related these findings to self-reported morbidity. METHODS: Inhabitants of 75 randomly selected households from a single village in western Côte d'Ivoire provided multiple faecal specimens and a single finger prick blood sample. The Kato-Katz technique and a formol-ether concentration method were employed to screen faecal samples for Schistosoma mansoni, soil-transmitted helminths and intestinal protozoa. Giemsa-stained blood smears were analysed for malaria parasites. A questionnaire was administered for collection of demographic information and self-reported morbidity indicators. RESULTS: Complete parasitological data were obtained for 500/561 (89.1%) participants, similarly distributed among sex, with an age range from 5 days to 91 years. The prevalences of Plasmodium falciparum, hookworms, Entamoeba histolytica/E. dispar, and S. mansoni were 76.4%, 45.0%, 42.2%, and 39.8%, respectively. Three-quarters of the population harboured three or more parasites concurrently. Multivariate analysis revealed significant associations between several pairs of parasites. Some parasitic infections and the total number of parasites were significantly associated with self-reported morbidity indicators. CONCLUSIONS: Our data confirm that polyparasitism is very common in rural Côte d'Ivoire and that people have clear perceptions about the morbidity caused by some of these parasitic infections. Our findings can be used for the design and implementation of sound intervention strategies to mitigate morbidity and co-morbidity.

Adolescent↗

PubMed2004

Prediction of anti-plasmodial activity of Artemisia annua extracts: application of 1H NMR spectroscopy and chemometrics.

We describe the application of 1H NMR spectroscopy and chemometrics to the analysis of extracts of Artemisia annua. This approach allowed the discrimination of samples from different sources, and to classify them according to anti-plasmodial activity without prior knowledge of this activity. The use of partial least squares analysis allowed the prediction of actual values for anti-plasmodial activities for independent samples not used in producing the models. The models were constructed using approximately 70% of the samples, with 30% used as a validation set for which predictions were made. Models generally explained >90% of the variance, R(2) in the model, and had a predictive ability, Q(2) of >0.8. This approach was also able to correlate 1H NMR spectra with cytotoxicity (R2=0.9, Q2=0.8). This work demonstrates the potential of NMR spectroscopy and chemometrics for the development of predictive models of anti-plasmodial activity.

Animals↗

PubMed2004

Use of relaxation-edited one-dimensional and two dimensional nuclear magnetic resonance spectroscopy to improve detection of small metabolites in blood plasma.

The 1H nuclear magnetic resonance (NMR) spectra of biological samples, such as blood plasma and tissues, are information rich but data complex owing to superposition of the resonances from a multitude of different chemical entities in multiple-phase compartments, hampering detection and subsequent resonance assignments. To overcome these problems, several spectral-editing NMR experiments are described here, combining spin-relaxation filters (based on T(1), T(rho), and T(2)) with both one-dimensional and two-dimensional (2D) NMR spectroscopy. These techniques enable the separation of NMR resonances based on their relaxation times and allow simplification of the complex spectra. In this paper, the approach is exemplified using a control human blood plasma, which is a complex mixture of proteins, lipoproteins, and small-molecule metabolites. In the case of T(1rho)- and T(2)-edited 2D NMR experiments, a "flip-back" pulse was introduced after the relaxation editing to make the phase cycling of the "relaxation filter" and the 2D NMR part independent, thus enabling easy implementation of the phase-sensitive 2D NMR experiments. These methods also permit much higher receiver gains to be used to reduce digitization error, in particular, for the small resonances, which are sometimes vitally important for metabonomics studies. Both pulse sequences and experimental results are discussed for T(1)-, T(1rho)-, and T(2)-filtered COSY, T(2)-filtered phase-sensitive DQF-COSY, and T(1), T(1rho)-, and T(2)-filtered TOCSY NMR.

Blood Chemical Analysis↗

PubMed2004

Metabolomic strategy for the classification and quality control of phytomedicine: a case study of chamomile flower (Matricaria recutita L.).

In order to improve the accuracy and consistency of control phytomedicine preparations worldwide, regulatory authorities are requesting research into new analytical methods for the stricter standardisation of phytomedicines. Such methods have to be both objective and robust, and should address the reproducibility of the content of the chemical profiles. NMR-based metabolomics, which combines high-resolution (1)H-NMR spectroscopy with chemometric analysis, has been employed as an innovative way to meet those demands. In this paper, chamomile flowers from three different geographical regions, namely, Egypt, Hungary and Slovakia were characterised using 1H-NMR spectroscopy followed by principal component analysis. It was found that the origin, purity and preparation methods contributed to the differences observed in prepared chamomile extracts. In addition, this method also enabled the elucidation of the molecular information embedded in the spectra responsible for the observed variability. The metabolomic strategy employed in the current study should provide an efficient tool for the quality control and authentication of phytomedicines.

Flowers↗

PubMed2003

Spectral editing and pattern recognition methods applied to high-resolution magic-angle spinning 1H nuclear magnetic resonance spectroscopy of liver tissues.

Principal component analysis (PCA) has been applied to three nuclear magnetic resonance (NMR) spectral editing methods, namely, the Carr-Purcell-Meiboom-Gill spin-echo, diffusion editing, and skyline projection of a two-dimensional J-resolved spectrum, obtained from high-resolution magic-angle spinning NMR spectroscopy of liver tissues, to distinguish between control and hydrazine-treated rats. The effects of the toxin on rat liver biochemistry were directly observed and characterized by depleted levels of liver glycogen, choline, taurine, trimethylamine N-oxide, and glucose and by elevated levels of lipids and alanine. The highly unsaturated omega-3-type fatty acid was observed for the first time in hydrazine-treated rat liver. The contributions of the metabolites to the separation of control from dosed liver tissues varied depending on the type of spectral editing method used. We have shown that subtle changes in the metabolic profiles can be selectively amplified using a metabonomics approach based on the different NMR spectral editing techniques in conjunction with PCA.

Alanine↗

PubMed2002

[Incidence of senile dementia and depression in elderly population in Xicheng District, Beijing, an epidemiologic study].

OBJECTIVE: To investigate the incidence of senile dementia and depression in the elderly and the factors correlative with these disorders. METHODS: All the non-case subjects investigated in a survey of prevalence of senile dementia and depression conducted among the elderly population in Xicheng District, Beijing in 1997 were followed up in 1999. The investigation procedure, instruments and diagnostic criteria were identical with those used in 1997 survey. RESULTS: The annual incidence rates of senile dementia was 0.89% in those aged 60 and over. The incidence rate of old males and that of the old females were not significantly different. The annual incidence rate of senile dementia in groups aged 60 approximately 64, 64 approximately 69, 70 approximately 74 75 approximately 79 80 approximately 84 85 approximately 89, and 90 and over were 0.15% 0.68 % 0.44% 1.32% 2.41% 5.72% and 5.13% respectively. The incidence rate in the elderly over 90 was lower than that in the group aged 85 approximately 89. The minimum annual incidence rate of depression in the elderly aged 60 and over was 1.28%. The incidence rate of depression was higher in the group with poorer health than in the group with better health. The incidence rates of moderate and severe dementia were not significantly different from those in 1989. CONCLUSION: The incidence rate of senile dementia in the elderly remains rather stable during this period of 10 years in Beijing city. The incidence rate of senile dementia is closely correlated with age. The incidence rate of depression in the elderly is remarkably correlated with health status. Senile dementia and depression may coexist in the same person.

Aged↗

PubMedDate not supplied

Biochemical characterization of rat intestine development using high-resolution magic-angle-spinning 1H NMR spectroscopy and multivariate data analysis.

We report details of metabolic profiles for small intestinal samples obtained using high-resolution magic-angle-spinning (HRMAS) (1)H NMR spectroscopy. Intact samples of jejunum and ileum from male Long Evans rats were analyzed on a 600 MHz spectrometer using standard one and two-dimensional (1)H NMR spectroscopic pulse sequences. The metabolic profiles of ileum and jejunum predominantly comprised a number of amino acids, lipids, glycerophosphocholine (GPC), choline, creatine, and ethanol, a number of carboxylic acids including acetate and lactate, and nucleoside bases including cytosine, isocytosine, and uracil. Principal component analysis (PCA) was applied to these NMR data to characterize the biochemical differences between jejunum and ileum tissues. Compared with ileum, jejunum contained higher levels of lipids, GPC, choline, lactate and creatinine, but lower levels of amino acids and acetate. In addition, the age dependence of the biochemical composition of intestinal tissues from young rats (15, 36 days and 3-4 months old) was studied. In general, levels of lipids, lactate, taurine and creatinine were positively correlated with age while amino acids and GPC decreased in the older age group. This study will provide a metabolic reference for further studies assessing the metabolic consequences of nutrition, stress and gut microbiota on intestinal composition.

Age Factors↗