Biomedical subjects

Li Ma

Publications and source records attributed to Li Ma.

At least 127 records · Page 7Linked to original sources

PubMed2003

Determination of abscisic acid by capillary electrophoresis with laser-induced fluorescence detection.

A novel method based on capillary electrophoresis coupled to laser-induced fluorescence detection (CE-LIF) was developed for the determination of abscisic acid (ABA), which is an essential phytohormone during plant growth and development. ABA was labeled with 8-aminopyrene-1,3,6-trisulfonate via reductive amination in presence of acetic acid and sodium cyanoborohydride. The derivatization yield was maximized by optimizing several derivatization parameters including derivatization reagent concentration, reaction temperature and time. The conjugate was separated and quantitated by CE-LIF. The linearity of ABA was determined in the range from 0.1 to 10 micromol l(-1) with a correlation of 0.9979. The derivatization limit of detection for ABA was found to be 56 fmol (corresponding to the concentration of 2.8 x 10(-8) mol l(-1)). The detection limit for ABA was 5.5 amol for an injection volume of 5 nl. As a preliminary application, the proposed method was successfully applied to determining trace amount of ABA in the crude extracts of tobacco without extra purification and enrichment procedure and showed a better selectivity and sensitivity than those conventional methods used in determination of ABA.

Abscisic Acid↗

PubMed2003

Pharmacological and genetic characterization of two selective serotonin transporter ligands: 2-[2-(dimethylaminomethylphenylthio)]-5-fluoromethylphenylamine (AFM) and 3-amino-4-[2-(dimethylaminomethyl-phenylthio)]benzonitrile (DASB).

The expression and function of the serotonin transporter (SERT) is important in the regulation of mood and emotion. Determination of SERT alterations in physiological and pathological states is essential for understanding the role of SERT in mood regulation, and in the etiology and therapy of psychiatric disorders. Two SERT ligands, AFM ([(3)H]2-[2-(dimethylaminomethylphenylthio)]-5-fluoromethylphenylamine) and DASB ([(3)H]3-amino-4-[2-(dimethylaminomethylphenylthio)]benzonitrile), have recently been developed for positron emission tomography (PET) imaging. The aim of the present study was to determine the selectivity of these compounds for SERT. Autoradiography of AFM or DASB binding was compared in the brains of mice with genetically normal, diminished, or absent SERT. In addition, the pharmacodynamic profile of [(3)H]AFM was examined in the mouse brain. The distribution of [(3)H]AFM and [(3)H]DASB binding in the normal brains was consistent with that of previously studied serotonin reuptake inhibitors. Both ligands had negligible binding in the brain of SERT knockout mice, and binding was reduced approximately 50% in heterozygote SERT mice. The K(d) of [(3)H]AFM binding in the cortex and midbrain was 1.6 and 1.0 nM, respectively. Competition studies showed that [(3)H]AFM has very low affinity for norepinephrine and dopamine transporters as well as 5-HT receptors, including 5-HT(1A), 5-HT(1B), 5-HT(2A), and 5-HT(2C) receptors. In addition, fenfluramine showed a low capability to compete with [(3)H]AFM. The present results suggest that both AFM and DASB are highly selective SERT ligands potentially suitable for use in human PET studies of SERT.

Aniline Compounds↗

PubMed2003

Simple and rapid catalytic spectrophotometric determination of superoxide anion radical and superoxide dismutase activity in natural medical vegetables using phenol as the substrate for horseradish peroxidase.

The coupling reaction of 4-aminoantipyrine (4-AAP) with phenol using the superoxide anion radical (O2-*) as oxidizing agent under the catalysis of horseradish peroxidase (HRP) was studied. Based on the reaction, O2-* produced by irradiating vitamin B2 (VB2) was spectrophotometrically determined at 510 nm. Under the optimum experimental conditions, the relationship between A510 and O2-* concentration was linear in the range 9.14x10(-6)-1.2x10(-4) mol L(-1). The detection limit was determined to be 1.37x10(-6) mol L(-1). A possible reaction mechanism was discussed. The effect of interferences and surfactants on the determination of O2-* was also investigated. The proposed method was applied to determine superoxide dismutase activity in garlic, scallion, and onion with satisfactory results.

Catalysis↗

PubMed2003

Functional studies of threonine 310 mutations in Glut1: T310I is pathogenic, causing Glut1 deficiency.

We have previously reported on a patient with the Glut1 deficiency syndrome (Online Mendelian Inheritance in Man number 606777) carrying a heterozygous T310I missense mutation in the GLUT1 gene (Klepper, J., Wang, D., Fischbarg, J., Vera, J. C., Jarjour, I. T., O'Driscoll, K. R., and De Vivo, D. C. (1999) Neurochem. Res. 24, 587-594). To investigate the molecular basis for the associated functional deficit, we constructed T310A, T310S, and T310I human GLUT1 mutants for expression in Xenopus laevis oocytes via cRNA injection. For all mutants, glucose transport was decreased, and osmotic water permeability (Pf) was increased. Km values for 3-O-methylglucose (3-OMG) uptake under zero-trans influx and equilibrium exchange influx conditions were, respectively, 13 +/- 1 and 68 +/- 5 mm for wild-type Glut1, 5 +/- 1 and 25 +/- 6 mm for T310A, 6 +/- 3 and 30 +/- 6 mm for T310I, and 5 +/- 1 and 48 +/- 5 mm for T310S. Compared with wild-type Glut1, we determined the following. (a). Zero-trans and equilibrium exchange influx values of 3-OMG were significantly decreased, respectively, 15 and 5% in T310A, 8 and 3% in T310I, and 40 and 34% in T310S mutants. (b). Zero-trans efflux of 3-OMG and dehydroascorbic acid uptake were significantly decreased in mutants. (c). The relative Pf values for T310A, T310I, and T310S were increased 3-, 4.8-, and 3.5-fold compared with wild-type values. We found a very high negative correlation between the rate of glucose uptake and Pf (-0.93), and between hydropathy and uptake (-0.92), a moderate correlation between hydropathy and Pf (0.73), and a minimal correlation between uptake, Pf, and molecular weight. These findings are consistent with a central role for hydropathy rather than size at position 310 of this mutation.

Animals↗

PubMed2003

A new strategy to amplify degraded RNA from small tissue samples for microarray studies.

RNA amplification methods have been used to facilitate making probes from small tissue samples for microarray studies. Our original amplification technique relied on driving the first reverse transcription with oligo(dT) with a T7 RNA polymerase promoter (T7dT) on the 5' end, and subsequent transcriptions with random 9mers with a T3 RNA polymerase promoter (T3N9). Thus, initially, poly(A)(+) RNA is amplified. This creates a potential problem: amplifications based on oligo(dT) priming could be sensitive to RNA degradation; broken mRNA strands should give rise to shorter cDNAs than those seen when intact templates are used. This would be especially troublesome when targets other than those corresponding to the 3' ends of transcripts are printed on an array. To solve this problem, we elected to prime cDNA synthesis with T3N9 at the beginning of each amplification cycle. Following two rounds of amplification, the resulting probes were comparable to those obtained with our original protocol or the Arcturus RiboAmp kit. We show below that as many as four rounds of amplification can be performed reliably. In addition, as predicted, the method works well with degraded templates.

3T3 Cells↗

PubMed2003

Ligand-dependent recruitment of the ErbB4 signaling complex into neuronal lipid rafts.

Neuregulin (NRG) regulates synapse formation and synaptic plasticity, but little is known about the regulation of NRG signaling at synapses. Here we show that the NRG receptor ErbB4 was localized in anatomically defined postsynaptic densities in the brain. In cultured cortical neurons, ErbB4 was recruited to the neuronal lipid raft fraction after stimulation by NRG. Along with ErbB4, adaptor proteins Grb2 and Shc were translocated to lipid rafts by NRG stimulation. In transfected human embryonic kidney 293 cells, the partitioning of ErbB4 into a detergent-insoluble fraction that includes lipid rafts was increased by PSD-95 (postsynaptic density-95), through interaction of the ErbB4 C terminus with the PDZ [PSD-95/Discs large/zona occludens-1] domains of PSD-95. Disruption of lipid rafts inhibited NRG-induced activation of Erk and prevented NRG-induced blockade of induction of long-term potentiation at hippocampal CA1 synapses. Thus, our results indicate that NRG stimulation causes translocation of ErbB4 into lipid rafts and that lipid rafts are necessary for signaling by ErbB4.

Adaptor Proteins, Signal Transducing↗

PubMed2003

Galanin GAL-R1 receptor null mutant mice display increased anxiety-like behavior specific to the elevated plus-maze.

The neuropeptide galanin coexists with norepinephrine and serotonin in neural systems mediating emotion. Previous findings suggested that galanin modulates anxiety-related behaviors in rodents. Three galanin receptor subtypes have been cloned; however, understanding their functions has been limited by the lack of galanin receptor subtype-selective ligands. To study the role of the galanin GAL-R1 receptor subtype in mediating anxiety-related behavior, we generated mice with a null mutation in the Galr1 gene. GAL-R1 -/- are viable and show no abnormalities in health, neurological reflexes, motoric functions, or sensory abilities. On a battery of tests for anxiety-like behavior, GAL-R1 -/- showed increased anxiety-like behavior on the elevated plus-maze test. Anxiety-related behaviors on the light/dark exploration, emergence, and open field tests were normal in GAL-R1 -/-. This test-specific anxiety-like phenotype was confirmed in a second, independent cohort of GAL-R1 null mutant mice and +/+ controls. Principal components factor analysis of behavioral scores from 279 mice suggested that anxiety-like behavior on the elevated plus-maze was qualitatively distinct from behavior on other tests in the battery. In addition, exposure to the elevated plus-maze produced a significantly greater neuroendocrine response than exposure to the light/dark exploration test, as analyzed in normal C57BL/6J mice. These behavioral findings in the first galanin receptor null mutant mouse are consistent with the hypothesis that galanin exerts anxiolytic actions via the GAL-R1 receptor under conditions of relatively high stress.

Animals↗

PubMed2003

RAGE is expressed in pyramidal cells of the hippocampus following moderate hypoxic-ischemic brain injury in rats.

The receptor for advanced glycation end products (RAGE) is a multi-ligand member of the immunoglobulin superfamily of cell surface molecules. The RAGE-ligand interaction has a putative role in a range of chronic disorders and is also known to contribute to both inflammatory/degenerative processes as well as regeneration in peripheral nerve injury. We have investigated the expression of RAGE in the moderate hypoxic-ischemic (HI) rat brain injury model in order to determine if this receptor is involved in the cellular perturbation mediated by ischemic stress. RAGE mRNA levels were detected by in situ hybridization using a DIG-labelled 48 mer oligonucleotide probe. Results showed a high level of expression of RAGE mRNA in the CA1/2 pyramidal cell layer of the hippocampus on the lesioned side of the brain 72 h after a moderate hypoxic-ischemic insult. RAGE was not expressed on the control side of the hippocampus. The RAGE-positive cells had a unique morphology, being angular in shape and atrophied with a condensed cell nucleus. They were NeuN-positive and were identified as dying cells by staining with thionin/acid fuchsin. A subset of cells was positive for cleaved Caspase-3, a marker for apoptosis. Together these data show that RAGE is expressed in dying neurons and suggest that RAGE may have a role in neuronal cell death mediated by ischemic stress. Identification of the ligand for RAGE in the ischemic brain may lead to a better understanding of RAGE-mediated cellular dysfunction in the CNS.

Animals↗

PubMed2003

Microglia density decreases with age in a mouse model of Huntington's disease.

Huntington's disease (HD) is characterized by selective neuronal loss and reactive gliosis. In the R6/2 transgenic HD mouse model, there is no selective cell loss, although astrocytosis has been reported. Since there have been no previous studies on microglia in this model, we have undertaken a detailed investigation of microglia in six different forebrain regions in the R6/2 mouse and their wild-type littermates at two time points. Microglia were identified using the histochemical marker isolectin B4 and interactions of genotype, region, and age were analyzed. Results showed that there was a significant decrease in the number of microglia with age in both wild-type and R6/2 brains, which was more pronounced in the transgenic mouse. There were also morphological changes with age observed in both genotypes. As early as 7 weeks of age, structural microglial abnormalities could be seen in R6/2 brains, including bulbous swellings and long stringy processes; comparable changes were seen at 16 weeks in wild-type brains. At 14.5 weeks, microglia in R6/2 mouse brains were smaller in size with condensed nuclei and fragmentation of their processes. We suggest that the density and morphology of microglia change with normal aging and that this process is accelerated in R6/2 brains. Such changes in the dynamic status of microglia may lead to an impairment of their neurosupportive functions. Further studies are needed to understand better the role of microglia in aging and neurodegeneration.

Aging↗

PubMed2003

Isolation and identification of mesenchymal stem cells from human fetal pancreas.

Mesenchymal stem cells (MSCs) have been cultured from many sources, including bone marrow and liver. To further support our hypothesis that MSCs exist in most postnatal tissues, we isolated a clonogenic, multipotent, rapidly proliferating population of cells from a fetal pancreas and termed them "pancreas-derived mesenchymal stem cells" (PMSCs). They withstood being passaged as many as 30 times without sustaining significant structural changes. In this study, we showed that PMSCs are positive for CD44, CD29, and CDI3 but negative for CD34 and HLA-DR and that they stained with collagen I and III but not with von Willebrand factor antibody. During the log phase of growth, PMSCs proliferated, doubling in population in about 30 hours. Cell-cycle analysis showed that more than 90% of cells were in the G0 and G1 phases, whereas a small subpopulation of cells were actively engaged in proliferation (S + G2 + M = 3.55%). Under differentiation culture conditions, PMSCs differentiated into cells of osteogenic, chondrogenic, and adipogenic lineages. These results demonstrate that PMSCs can be isolated from human fetal pancreas by means of their adherent ability and that they are capable of self-renewal, propagation, and multipotent differentiation.

Base Sequence↗

PubMed2003

Brain region-specific alterations of 5-HT2A and 5-HT2C receptors in serotonin transporter knockout mice.

The aim of the present studies was to determine the effects of reduced or absent serotonin (5-HT) transporters (5-HTTs) on 5-HT2A and 5-HT2C receptors. The density of 5-HT2C receptors was significantly increased in the amygdala and choroid plexus of 5-HTT knockout mice. On the other hand, the density of 5-HT2A receptors was significantly increased in the hypothalamus and septum, but reduced in the striatum, of 5-HTT knockout mice. However, 5-HT2A mRNA was not changed in any brain region measured. 5-HT2C mRNA was significantly reduced in the choroid plexus and lateral habenula nucleus of these mice. The function of 5-HT2A receptors was evaluated by hormonal responses to (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI). Oxytocin, but not adrenocorticotrophic hormone or corticosterone, responses to DOI were significantly greater in 5-HTT knockout mice. In addition, Gq and G11 proteins were not significantly changed in any brain region measured. The present results suggest that the constitutive alteration in the function of 5-HTTs changes the density of 5-HT2A and 5-HT2C receptors in a brain region-specific manner. These changes may not be mediated by alterations in their gene expression or in the level of Gq/11 proteins. The alterations in these receptors may be related to the altered behaviors of 5-HTT knockout mice.

Animals↗

PubMed2003

Mucosal repair and COX-2 inhibition.

The healing of gastric ulcer is a complicated process that involves the proliferation of epithelial and endothelial cells and the concerted actions of a wide range of growth factors. Prostaglandins play an important role in ulcer healing. Expression of cyclooxygenase-2 (COX-2) is markedly upregulated around the margins of gastric ulcers and its inhibition leads to a delay of ulcer healing. Several of the growth factors that promote ulcer healing may work in part through COX-2-dependent mechanisms. Angiogenesis, which is crucial to ulcer healing, is tightly regulated by growth factors. Treatment with selective COX-2 inhibitors appears to alter the balance of serum levels of growth factors, favoring an inhibition of angiogenesis. Given the importance of COX-2 in regulating ulcer healing, caution should be taken in the use of selective inhibitors of COX-2 by patients at risk of ulcer disease.

Animals↗

PubMed2003

Predicting the impact of antiretrovirals in resource-poor settings: preventing HIV infections whilst controlling drug resistance.

There is currently an opportunity to carefully plan the implementation of antiretroviral (ARV) therapy in the developing world. Here, we use mathematical models to predict the potential impact that low to moderate usage rates of ARVs might have in developing countries. We use our models to predict the relationship between the specific usage rate of ARVs (in terms of the percentage of those infected with HIV who receive such treatment) and: (i) the prevalence of drug-resistant HIV that will arise, (ii) the future transmission rate of drug-resistant strains of HIV, and (iii) the cumulative number of HIV infections that will be prevented through more widespread use of ARVs. We also review the current state of HIV/AIDS treatment programs in resource-poor settings and identify the essential elements of a successful treatment project, noting that one key element is integration with a strong prevention program. We apply both program experience from Haiti and Brazil and the insights gleaned from our modeling to address the emerging debate regarding the increased availability of ARVs in developing countries. Finally, we show how mathematical models can be used as tools for designing robust health policies for implementing ARVs in developing countries. Our results demonstrate that designing optimal ARV-based strategies to control HIV epidemics is extremely complex, as increasing ARV usage has both beneficial and detrimental epidemic-level effects. Control strategies should be based upon the overall impact on the epidemic and not simply upon the impact ARVs will have on the transmission and/or prevalence of ARV-resistant strains.

Anti-Retroviral Agents↗

PubMed2003

[Influence of large amount of shengmai injection on blood coagulation in patients with chronic heart failure].

OBJECTIVE: To investigate the effect of Shengmai Injection (SMI) on blood coagulation in patients with chronic heart failure (CHF). METHODS: Sixty patients with CHF were randomly divided into two groups, the 30 patients in the treated group were treated with SMI plus conventional treatment of western medicine, and the 30 in the control group treated with conventional treatment alone. The changes of cardiac function were observed and levels of plasma P-selectin, von Willebrand's factor (vWF) and D-dimer were determined. RESULTS: The total effective rate and the markedly effective rate in the treated group were higher than those in the control group respectively. The levels of P-selectin, vWF and D-dimer lowered in both groups significantly after treatment, but the effect of lowering was better in the treated group than that in the control group. CONCLUSION: Hypercoagulative state exist in patients with chronic heart failure. SMI could improve the state in patients, which may reduce the occurrence and developing of emboic events to certain extent.

Aged↗

PubMed2003

[Expression of matrix metalloproteinases in lung tissue and levels of some cytokines in bronchoalveolar lavage fluid in the obstructive emphysema rat models].

OBJECTIVE: To observe the changes of matrix metalloproteinase-2 (MMP-2), MMP-9 and interleukin-10 (IL-10), tumor necrosis factor-alpha (TNFalpha) in lung tissue of the obstructive emphysema rat models and to evaluate the relationship between these changes and emphysema formation. METHODS: The rat emphysema models were established by exposure to cigarette smoking. Pulmonary function tests were performed to evaluate the forced expiratory volume in 0.3 second (FEV(0.3)), FEV(0.3)/forced vital capacity (FVC) and functional residual capacity (FRC). The morphological indices of emphysema were measured by computer image analyzer. The protein expression and enzymatic activity of MMPs in lung tissue were observed. The contents of IL-10 and TNFalpha in bronchoalveolar lavage fluid (BALF) were measured. RESULTS: Pulmonary function test showed that in model group the FEV(0.3)/FVC was decreased, whereas the FRC was increased significantly than those in control group (P < 0.01, respectively). There was a significant decrease in the relative content of elastin in lung tissue in model group than that in control group. The expression and enzymatic activity of MMP-2 and MMP-9 in lung tissue, the counts of total leukocytes and neutrophils and the level of TNFalpha in BALF were significantly elevated, but the level of IL-10 in BALF was significantly reduced in model group compared with those in control group (P < 0.01, respectively). There were statistically significant positive correlations between the enzymatic activity of MMP-2, MMP-9 and the total leukocyte counts (P < 0.01, respectively), and significant negative correlations between the enzymatic activity of MMP-2, MMP-9 and the content of elastin (P < 0.05, respectively). CONCLUSIONS: MMP-2, MMP-9, IL-10 and TNFalpha may play an important role in the formation of obstructive emphysema in rat models caused by passive smoking.

Animals↗

PubMed2003

[Study of biological characteristics of murine dermal mesenchymal stem cells and their enhancement of hematopoiesis recovery].

OBJECTIVE: To study the characteristics of dermal mesenchymal stem cells (DMSC), and explore whether they could enhance hematopoiesis recovery in vivo as well as facilitate proliferation and differentiation of hematopoietic cells in vitro. METHODS: Multipotential stem cells from the murine dermal mesenchyme were dissociated and cultured as donor cells. After 2 approximately 3 passages, the growth status, cell cycle, immunophenotype and morphology of DMSC were analyzed. Hematopoietic cells were plated onto a feeder layer formed by DMSC, cell count and CFU-GM yields were observed dynamically. Female mice received 5 Gy (137)Cs radiation were injected with DMSC cultured for 2 - 3 passages via tail vein. Cell count and CFU-GM yields of the bone marrow were observed regularly. Pathological study of the liver, spleen and bone marrow was done to evaluate hematopoiesis recovery. RESULTS: Murine DMSC are adherent cells with a morphology of fibroblastoid and spindle and multiangle in shape. Immunophenotypes showed that CD(45), CD(34), HL-DR positive DMSC were 1 - 3%, CD(44) and CD(13) positive DMSC 75 approximately 95%. Cell cycle assay demonstrated 83% of DMSC being G(0)/G(1) phase. In vitro, the total cell count and CFU-GM yields in the experimental group were higher than those of the long-term culture bone marrow cells by the third week. The DMSC can sufficiently support the proliferation and differentiation of hematopoietic cells for seven weeks. In vivo, peripheral granulocytic count, cells in the bone marrow of one femoral bone and CFU-GM by the third week in the experimental group were much higher than those of controls. Genetic assay of the murine blood demonstrated Y chromosome. CONCLUSION: The DMSC have characteristics of stem cells. DMSC sped up hematopoiesis recovery of irradiated mice. DMSC as a feeder layer can support proliferation and differentiation of hematopoietic cells.

Animals↗

PubMed2003

[Expression of homeobox gene Msx-1, Msx-2 and Dlx-2 during murine mandibular first molar development].

OBJECTIVE: To observe the expression of homeobox gene Msx-1, Msx-2 and Dlx-2 during murine mandibular first molar development. METHODS: The murine heads or mandibles on embryonic days 11-18 (E11-18) and postnatal day 1-3 (P1-3) were removed, fixed and embedded, 5 micro m serial sections were cut in the coronal plane. Msx-1, Msx-2 and Dlx-2 RNA probes were synthesized by in vitro transcription and labeled with digoxigenin. Msx-1, Msx-2 and Dlx-2 mRNA expression was observed after in situ hybridization. RESULTS: During molar development Msx-1 transcripts appeared only in mesenchymal cells, not in epithelial cells. Msx-2 and Dlx-2 both expressed in the epithelial and mesenchymal cells. At the initiation stage of the molar development Msx-2 and Dlx-2 had similar expression. At the bud stage (E13-14) Msx-2 mRNA signaling was intensive in the enamel organ and slight in the dental mesenchyme; Dlx-2 signaling was stronger in the dental papilla. At cap stage (E15-16) Msx-2 showed prominent mRNA signaling in enamel knot and Dlx-2 was maximal in the dental papilla. At the late bell stage (P2-3) Msx-2 transcripts were observed in odontoblasts but not labeled in ameloblasts, and Dlx-2 transcripts appeared in ameloblasts but no labeling was seen in odontoblasts. CONCLUSIONS: Msx-1, Msx-2 and Dlx-2 are expressed in various patterns during murine mandibular first molar development, suggesting they possibly play a role in the interaction between the epithelium and mesenchyme during the molar development.

Animals↗

PubMed2003

[Epidemiological study of rotavirus diarrhea in Beijing, China - a hospital-based surveillance from 1998 - 2001].

OBJECTIVE: To provide information on epidemiology of rotavirus infection in Beijing, China. METHODS: An ongoing hospital-based surveillance was conducted among children < 5yr old with acute diarrhea according to WHO generic protocol (CID-98). During a 3-year study (Apr. 1998 to Mar. 2001), a total of 484 stool samples were collected from 1 457 patients, including 275 samples from 1 048 outpatients and 209 samples from 409 inpatients. RESULTS: The overall detection rate of rotavirus infection was 25.4%. Rotavirus was responsible for 27.3% of diarrhea inpatients on a yearly base, and 46.2% during rotavirus season. Two peaks of diarrhea were observed each year, one in the summer (June-Sep.) due to bacterial dysentery (16.7%) and another in fall winter (Oct.-Dec.) due to rotavirus infection (23.0%). The detection rate on rotavirus was the highest in age group of 6 - 11 months (38.2%), followed by 1 - 2 years old (28.5%). Ninety six point eight percentage of children were infected under 3 years of age. The number of deaths, possibly caused by rotavirus diarrhea were accounted for 40% of all diarrhea deaths and 11.1% of the total deaths. Serotyping of 123 rotavirus isolates showed that serotype G1 (55.3%) was predominant, followed by G2 (26.8%), G3 (9.8%), G4 (0.8%), and 10 isolates (8.1%) remained non-typeable. Mixed infections (0.8%) seemed to be rare. CONCLUSION: Rotavirus diarrhea was an important infectious disease among children in Beijing. Safe and effective rotavirus vaccines for the prevention of severe diarrheas and the reduction of treatment costs are of significant importance to China.

Age Factors↗