Biomedical subjects

J Zhou

Publications and source records attributed to J Zhou.

At least 91 records · Page 5Linked to original sources

PubMed2003

Pollution reduction at wastewater treatment facilities through thermophilic sludge digestion.

Wastewater treatment facilities produce large amounts of sludge, which is a pollutant to the environment if not properly managed. Among the three most common methods (landfills, land application, incineration) of sludge disposal, thermophilic digestion to produce Class-A biosolids for land application is recognized as the most cost-effective, environmentally sustainable option. Full-scale experience revealed that thermophilically digested biosolids consumed a higher dosage of chemicals for conditioning and dewatering than conventionally (mesophilically) digested biosolids. This paper presents findings of a recent study to investigate how major operational parameters affect dewatering properties of thermophilically digested biosolids, and to search for the inter-relationship between digestion, characteristics of digested biosolids, and dewatering properties of thermophilic biosolids. Experimental work was carried out using bench-scale aerobic digesters. This study found that feed sludge composition has a significant effect on dewaterability. A higher content of secondary sludge resulted in poorer dewaterability in undigested and digested sludge. Dewatering properties are sensitive to a temperature effect. Such an effect is physical-chemical in nature. Excessive high shear results in significant deterioration in dewaterability. Thermophilic digestion resulted in a substantial increase in ammonia and phosphate concentrations, but these two factors seem to not have much impact on dewaterability. Instead, cellular biopolymers have a significant role in affecting dewatering properties of thermophilically digested biosolids.

Biopolymers↗

PubMed2002

A two-species test of the hypothesis that spatial isolation influences microbial diversity in soil.

The hypothesis that spatial isolation is a key determinant of microbial community structure in soils was evaluated by examining the competitive dynamics of two species growing on a single resource in a uniform sand matrix under varied moisture content. One species dominated the community under highly connected, saturated treatments, suggesting that these conditions allow competitive interactions to structure the community. As moisture content decreased, however, the less competitive species became established in the community. This effect was most pronounced at a matric water potential of -0.14 MPa where estimates of final population density and species fitness were equal. A second but more closely related species pair exhibited a similar response to decreasing moisture, suggesting that the effects of spatial isolation we observed are not simply a species-pair-specific phenomenon. These findings indicate that spatial isolation, created by low moisture content, plays an important role in structuring soil microbial communities.

Cupriavidus necator↗

PubMed2002

Genomic-scale analysis of gene expression profiles in TNF-alpha treated human umbilical vein endothelial cells.

OBJECTIVE AND DESIGN: TNF-alpha is a potent proinflammatory cytokine that plays an important role in immunity and inflammation, and in the control of cell proliferation, differentiation and programmed cell death. However, it is known that TNF-alpha is also the founding member of a still growing family of cytokines with diverse bioregulative functions. Its detailed molecular mechanisms on endothelial activation and injury remain to be elucidated. This study was aimed at determining genomic-scale gene expression profiles in TNF-alpha treated human endothelial cells. MATERIALS AND METHODS: In this study cultured human umbilical vein endothelial cells (HUVECs) were stimulated with TNF-alpha (10 ng/ml) for 2 and 16 h, respectively, and the gene expression pattern was profiled using a cDNA array representing 14,000 gene/cDNA clusters. RESULTS: In total, 72 known human genes were identified the expression levels of which altered over 2-fold in response to TNF-a stimulation. Such alteration was confirmed for IL-8 and MCP-1, with an independent quantitative mRNA assay. It was observed that genes with related biological functions were often temporally co-regulated. CONCLUSIONS: These results indicate the transcriptional pathways mediated by TNF-alpha inside the HUVECs. Expression profiling in HUVECs responding to TNF-alpha stimulation should give an understanding of the molecular mechanisms involved in vascular inflammation.

Cells, Cultured↗

PubMed2002

Uptake and pathogenic effects of amyloid beta peptide 1-42 are enhanced by integrin antagonists and blocked by NMDA receptor antagonists.

Many synapses contain two types of receptors - integrins and N-methyl-D-aspartate (NMDA) receptors - that have been implicated in peptide internalization. The present studies tested if either class is involved in the uptake of the 42-residue form of amyloid beta peptide (Abeta1-42), an event hypothesized to be of importance in the development of Alzheimer's disease. Cultured hippocampal slices were exposed to Abeta1-42 for 6 days in the presence or absence of soluble Gly-Arg-Gly-Asp-Ser-Pro, a peptide antagonist of Arg-Gly-Asp (RGD)-binding integrins, or the disintegrin echistatin. Abeta uptake, as assessed with immunocytochemistry, occurred in 42% of the slices incubated with Abeta peptide alone but in more than 80% of the slices co-treated with integrin antagonists. Uptake was also found in a broader range of hippocampal subfields in RGD-treated slices. Increased sequestration was accompanied by two characteristics of early stage Alzheimer's disease: elevated concentrations of cathepsin D immunoreactivity and activation of microglia. The selective NMDA receptor antagonist D-(-)-2-amino-5-phosphonovalerate completely blocked internalization of Abeta, up-regulation of cathepsin D, and activation of microglia. Our results identify two classes of receptors that cooperatively regulate the internalization of Abeta1-42 and support the hypothesis that characteristic pathologies of Alzheimer's disease occur once critical intraneuronal Abeta concentrations are reached.

2-Amino-5-phosphonovalerate↗

PubMed2002

The preparation and characterization of an antimicrobial polypeptide from the loach, Misgurnus anguillicaudatus.

Using Sephadex G-50 gel filtration, DEAE-52 cellulose ion-exchange chromatography, and an improved polyacrylamide gel electrophoresis together with electroelution, a novel polypeptide with antimicrobial activity in vitro was isolated and characterized from loach, Misgurnus anguillicaudatus. The polypeptide, named MAPP, contains about 94 residues containing l0 different amino acids, of which cysteine was the most abundant. No alkaline residue was found in MAPP. MAPP is a single-chain polypeptide with Mw of about 9800Da and pI of about 4.78; the N-terminus of MAPP was CFGWN. MAPP showed good inhibition of various bacteria including Bacillus subtilis, Escherichia coli, and Staphylococcus aureus. MAPP is thermally stable with more than 70% inhibitory bioactivity remaining after treatment at 60 degrees C for 30min. In addition, MAPP could inhibit the autoxidation of pyrogallol with a high efficiency. Similarity searches by comparing amino acid composition, MS-fingerprint, and the N-terminus of MAPP demonstrated that no protein exactly matched MAPP in databases around the world.

Animals↗

PubMed2002

Cord blood mononuclear cell cytokine responses in relation to maternal house dust mite allergen exposure.

BACKGROUND: Cord blood mononuclear cells have demonstrated specific immune responses to environmental allergens. OBJECTIVE: To establish whether the nature of this response is related to the level of maternal antenatal exposure to house dust mite (HDM) allergen and, hence, whether antenatal allergen avoidance may have a role in the prevention of allergic sensitization in children. METHODS: Children with a family history of asthma were recruited antenatally as subjects in a randomised controlled trial: the Childhood Asthma Prevention Study. HDM allergen (Der p 1) concentrations were measured in dust collected from the maternal bed at 36 weeks gestation. Cord blood mononuclear cells were stimulated in culture, separately, with phytohaemaglutinin (PHA) and HDM extract. Cytokine IL-4, IL-5, IL-10 and IFN-gamma concentrations in supernatant were measured by ELISA. mRNA signals for these cytokines were measured using RT-PCR. RESULTS: The median concentration of HDM allergen was 18.4 microg/g (interquartile range 7.3-35.3 microg/g). Median concentrations of IL-4, IL-5, IL-10 and IFN-gamma, after PHA stimulation were 4, 19, 401 and 1781 pg/mL, respectively. After HDM allergen stimulation the median concentrations were 0, 0, 20 and 14 pg/mL, respectively. The distribution of mRNA cytokine signals was similar. Neither cytokine protein concentrations nor cytokine mRNA signal levels were correlated with the concentration of HDM allergen in the mothers' beds at 36 weeks gestation. CONCLUSION: These findings do not support the view that the prevention of allergic disease in children requires the institution of HDM avoidance interventions during pregnancy.

Air Pollution, Indoor↗

PubMed2002

Soils of the Chinese Hubei province show a very high diversity of Sinorhizobium fredii strains.

Biodiversity studies of native soybean-nodulating rhizobia in soils from the Chinese Hubei province (Honghu county; pH 8, alluvial soil) have been carried out. Inoculation of an American (Williams) and an Asiatic (Peking) soybean cultivar with eleven soil samples led to the isolation of 167 rhizobia strains. The ratio (%) of slow-/fast-growing isolates was different depending on the trap plant used. All isolates were able to nodulate both cultivars, although the N2-fixation efficiency (measured as plant-top dry weight) was different among them. A total of thirty-three isolates were selected for further characterisation on the basis of physiological parameters, PCR-RFLP of symbiotic genes and Low Molecular Weight RNA, lipopolysaccharide, protein and plasmid profiles. Low Molecular Weight RNA profiling indicates that all the isolates belong to species Sinorhizobium fredii. The dendrogram obtained with the physiological parameters has been useful to classify the isolates at strain level, although plasmid profiling was the most discriminating technique to detect differences among the analysed soybean-rhizobia isolates, showing there is not two isolates identical each other. Plasmid profile analyses also revealed that some of the investigated strains contain low molecular weight plasmids (7-8-kb). They are, to our knowledge, the smallest ever found in rhizobia and they could be the starting point for the construction of the first group of vectors based on a native rhizobia replicon.

China↗

PubMed2002

Platelet activity and in vivo arterial thrombus formation in rats with mild hyperhomocysteinaemia.

Elevated plasma levels of total homocysteine (hcy) have been associated with an increased occurrence of arterial thrombosis. In the present study, we investigated the influence of hyperhomocysteinaemia on platelet aggregation and arterial thrombus formation in vivo. Fifty-one rats were included in the study, of which 29 received hcy in the drinking water for 4 weeks. Blood samples were withdrawn for measurement of platelet count and mean platelet volume. Platelet aggregation response in platelet-rich plasma following adenosine diphosphate or collagen stimulation were examined. In vivo thrombus formation was investigated by transillumination and videotape recording of the rat femoral artery after a thrombogenic injury was established. Off-line videotape analysis using computer-assisted planimetry permitted quantification of the thrombus area, and area versus time curves were obtained. In the intervention group receiving hcy, total hcy in plasma increased two-fold to 14.3 micromol/l, as compared with 7.3 micromol/l in the control group (P < 0.001). The platelet count and mean platelet volume did not differ between the two groups. In vivo thrombus formation expressed as the area under the curve or maximum thrombus area was not found to be altered in the presence of an increased homocysteine level, neither was adenosine diphosphate-induced platelet aggregation. However, collagen-induced platelet aggregation significantly decreased in the hcy group (P = 0.02). Pro-thrombotic effects of isolated mild hyperhomocysteinaemia are not supported by the present study in rats.

Adenosine Diphosphate↗

PubMed2002

Production of value added products from separately collected urine.

For many reasons it is advantageous to collect urine separately and collection systems, so called "no-mix-toilets" exist. Therefore, this work deals with some methods to make use of this urine to produce value added products: IBDU and ammonia water. It could be shown that urea can be converted to IBDU only after concentrating urine. With air stripping and absorption ammonificated urine can be treated very effectively and a solution of 10% w/w of ammonia can be obtained.

Ammonia↗

PubMed2001

Stem-loop SL4 of the HIV-1 psi RNA packaging signal exhibits weak affinity for the nucleocapsid protein. structural studies and implications for genome recognition.

Encapsidation of the genome of the human immunodeficiency virus type-1 (HIV-1) during retrovirus assembly is mediated by interactions between the nucleocapsid (NC) domains of assembling Gag polyproteins and a approximately 110 nucleotide segment of the genome known as the Psi-site. The HIV-1 Psi-site contains four stem-loops (SL1 through SL4), all of which are important for genome packaging. Recent isothermal titration calorimetry (ITC) studies have demonstrated that SL2 and SL3 are capable of binding NC with high affinity (K(d) approximately 140 nM), consistent with proposals for protein-interactive functions during packaging. To determine if SL4 may have a similar function, NC-interactive studies were conducted by NMR and gel-shift methods. In contrast to previous reports, we find that SL4 binds weakly to NC (K(d)=(+/-14 microM), suggesting an alternative function. NMR studies indicate that the GAGA tetraloop of SL4 adopts a classical GNRA-type fold (R=purine, N=G, C, A or U), a motif that stabilizes RNA tertiary structures in other systems. In combination with previously reported gel mobility studies of Psi-site deletion mutants, these findings suggest that SL4 functions in genome recognition not by binding to Gag, but by stabilizing the structure of the Psi-site. Differences in the affinities of NC for SL2, SL3 and SL4 stem-loops can now be rationalized in terms of the different structural properties of stem loops that contain GGNG (SL2 and SL3) and GNRA (SL4) sequences.

Amino Acid Sequence↗

PubMed2001

Recombinant paramyosin (rec-Sj-97) tested for immunogenicity and vaccine efficacy against Schistosoma japonicum in mice and water buffaloes.

A primary vaccine candidate antigen against schistosomiasis is paramyosin (pmy), a myofibrillar protein found exclusively in invertebrates. Here we report the results of vaccine trials against the Asian schistosome undertaken on inbred and outbred mice and water buffaloes using a bacterially expressed and purified form of Schistosoma japonicum pmy (rec-Sj-97). Vaccination of the mice resulted in high levels of specific anti-pmy IgG antibodies when compared with adjuvant controls and significant reduction in worm burdens and in liver eggs. Furthermore, a significant reduction in liver eggs was recorded in two of the three water buffalo vaccine trials undertaken and, in all three trials, high levels of specific anti-pmy IgG antibodies were generated. There was no evidence of any toxic effects and the vaccine preparations and Quil A adjuvant were clearly well tolerated. The development of a vaccine intended for livestock animals such as bovines would be beneficial in two ways; directly by blocking transmission of schistosomiasis to humans and economically by contributing to healthier livestock. We are encouraged by the consistent efficacy in the mouse and the buffalo vaccine trials that resulted in a significant decrease in liver eggs. Indeed, predictions from mathematical models indicate that an egg reduction effect of 42-45% in buffaloes would be sufficient when combined with human treatment to control schistosomiasis japonica in the marshes and lakes along the middle and upper reaches of the Yangtze River, the most highly endemic areas for the disease in China.

Animals↗

PubMed2001

Resistance to neutralizing antibody and expanded coreceptor usage are associated with human immunodeficiency virus type 1 isolates derived from chimpanzees with pathogenic infections.

Immunologic and biologic factors associated with the progression to AIDS in HIV-1-infected chimpanzees were investigated. Chimpanzee C499 was euthanized in 1996 as a result of the development of AIDS approximately 11 years after infection with HIV-1. At the time of initial disease development (September 1995), blood from this animal was transfused to an uninfected chimpanzee, C455, resulting in a rapid loss of CD4(+) T cells. Virus isolates were derived from both animals and termed HIV-1(JC) (derived from C499 at the time of disease development; JC isolate) and HIV-1(NC) (derived from C455 1 month posttransfusion; NC isolate). In vitro studies demonstrate that the parental viruses used to inoculate C499 were susceptible to neutralization by serum from that animal. In contrast, serum from C499 at any time was unable to neutralize the JC or NC isolates. Similarly, the JC and NC isolates were highly resistant to neutralization by serum from C455. However, serum from C455 was also unable to neutralize either of the parental viruses or any of the normally neutralization sensitive isolates tested. Serum samples from the two additional chimpanzees that were inoculated with the NC isolate were also unable to neutralize these isolates. Coreceptor usage of the uncloned JC and NC isolates was somewhat expanded when compared with that of LAV1b and SF2. However, molecular clones derived from the JC and NC isolates (JC16 and NC7) displayed only a limited coreceptor repertoire despite having unique V3 loop sequences. The results suggest that the JC and NC isolates are neutralization escape mutants and display a different phenotype than the parental strains LAV1b and SF2.

Animals↗

PubMed2001

Aclarubicin treatment restores SMN levels to cells derived from type I spinal muscular atrophy patients.

Proximal spinal muscular atrophy (SMA) is a common motor neuron disorder caused by mutation of the telomeric survival of motor neuron gene SMN1. The centromeric survival of motor neuron SMN2 gene is retained in all SMA patients but does not produce sufficient SMN protein to prevent the development of clinical symptoms. The SMN1 and SMN2 genes differ functionally by a single nucleotide change. This change affects the efficiency with which exon 7 is incorporated into the mRNA transcript. Thus, SMN2 produces less full-length mRNA and protein than SMN1. We have screened a library of compounds in order to identify ones that can alter the splicing pattern of the SMN2 gene. Here, we report that the compound aclarubicin increases the retention of exon 7 into the SMN2 transcript. We show that aclarubicin effectively induces incorporation of exon 7 into SMN2 transcripts from the endogenous gene in type I SMA fibroblasts as well as into transcripts from a SMN2 minigene in the motor neuron cell line NSC34. In type I fibroblasts, treatment resulted in an increase in SMN protein and gems to normal levels. Our results suggest that alteration of splicing pattern represents a new approach to modification of gene expression in disease treatment and demonstrate the feasibility of high throughput screens to detect compounds that affect the splicing pattern of a gene.

Aclarubicin↗

PubMed2001

[Curative effect of soybean lecithin on cerebral infarction].

OBJECTIVE: To investigate the clinical curative effect of soybean lecithin on cerebral infarction. METHODS: 542 patients with cerebral infarction within 48 h after the onset with the nervous function defect scores of 31-35 were divided into 3 groups: basic treatment group, 60 cases, with conventional treatment; citicoline group, 122 patients, with conventional treatment and citicoline; and soybean lecithin group, 360 patients, with conventional treatment and soybean lecithin 10 g tid. For all patients, treatment began sometime within 48 hours after the onset. The treatment course lasted 28 days. RESULTS: When the course was over, the infarct volumes in basic group citicoline group, and soybean lecithin group, were 7.6 cm3 +/- 2.9 cm3, 7.3 cm3 +/- 3.1 cm3, and 6.4 cm3 +/- 2.7 cm3 respectively (F = 7.371, P = 0.0007). The basic group and citicoline group being compared with the soybean group by Dunnett test, t = 4.387 and 3.969 respectively, P < 0.01. The nervous function defect integral in the 3 groups decreased 14.2 +/- 10.93, 15.0 +/- 9.0, and 18.5 +/- 10.9 respectively. Two-way analysis of variance of drug kind and beginning time of treatment showed the value of F in drugs as 6.250, P = 0.0021, and value of F in times as 0.9417, P = 0.4201. In the order of death,deterioration, no improvement, improvement, significant improvement, and recovery, the Ridit values for the comprehensive curative effect in the 3 groups were 0.4003, 0.4118, and 0.54 5 respectively; chi2 = 27.89, P < 0.001. CONCLUSION: Soybean lecithin is effective in treatment of acute cerebral infarction. The mechanism may be that soybean lecithin lowers the decrease of brain phospholipid content in brain ischemia.

Cerebral Infarction↗

PubMed2001

Huperzine A attenuates cognitive deficits and hippocampal neuronal damage after transient global ischemia in gerbils.

The protective effects of huperzine A on transient global ischemia in gerbils were investigated. Five min of global ischemia in gerbils results in working memory impairments shown by increased escape latency in a water maze and reduced time spent in the target quadrant. These signs of dysfunction are accompanied by delayed degeneration of pyramidal hippocampal CA1 neurons and by decrease in acetylcholinesterase activity in the hippocampus. Subchronic oral administration of huperzine A (0.1 mg/kg, twice per day for 14 days) after ischemia significantly reduced the memory impairment, reduced neuronal degeneration in the CA1 region, and partially restored hippocampal choline acetyltransferase activity. The ability of huperzine A to attenuate memory deficits and neuronal damage after ischemia might be beneficial in cerebrovascular type dementia.

Acetylcholinesterase↗

PubMed2001

Sustained activation of p34(cdc2) is required for noscapine-induced apoptosis.

Mitotic arrest and subsequent apoptosis has been observed in many types of cells treated with anti-microtubule agents. However, the molecular mechanisms underlying the two events as well as their relationship are not well understood; on the contrary, there has been increasing evidence indicating that anti-microtubule agents might induce apoptosis via signaling pathways independent of mitosis. In this study, we found that apoptosis induced by noscapine, an anti-microtubule drug previously shown to cause both mitotic arrest and apoptotic cell death, was blocked by inhibiting p34(cdc2) activity with olomoucine in FM3A murine mammary carcinoma cells or by reducing the level and activity of p34(cdc2) in a mutant cell line FT210 derived from FM3A. Furthermore, transfection of the mutant FT210 cells with wild-type p34(cdc2) restored their ability to undergo mitotic arrest and then apoptosis in response to noscapine. Thus, we conclude that sustained activation of the p34(cdc2) kinase during mitotic arrest is required for subsequent apoptosis induced by noscapine, establishing a link between the two events.

Animals↗

PubMed2001

Development of purinergic sensitivity in sensory neurons after peripheral nerve injury in the rat.

Purinoceptors are present in the cell bodies as well as in both peripheral and central terminals of many sensory neurons, where they may play a role in sensory transmission, including pain. After peripheral nerve injury at the spinal nerve level, some axotomized afferent neurons develop ongoing discharges (ectopic discharges) that originate in the dorsal root ganglion (DRG). In the present study, we attempted to determine whether or not purinergic sensitivity develops in injured sensory neurons which display ectopic discharges, as well as in silent units. The L(4) and L(5) spinal nerves were ligated in Sprague-Dawley rats. Four to 21 days after the surgery, the DRGs with attached dorsal roots and spinal nerves were removed and ectopic discharges were recorded from teased dorsal root fascicles using an in vitro recording set-up. The results showed that 75.6 and 65.1% of the chronically axotomized DRG neurons displaying ectopic discharges enhanced their activity after application of adenosine 5'-triphosphate (ATP, 1 mM) or alpha,beta-methylene ATP (mATP, 100 microM), respectively. In addition, application of these purinoceptor agonists evoked activity in 7 of 28 axotomized DRG neurons, which did not show ongoing discharges. In contrast, only 1 of 34 DRG neurons acutely isolated from normal rats (no previous spinal nerve ligation) responded to either mATP or ATP. In most of the tested units, mATP-induced enhancement of ectopic discharges was blocked by non-specific P2X receptor antagonists, PPADS or suramin. The data from the present study suggest that purinergic sensitivity develops in DRG neurons after chronic axotomy and that this purinergic sensitivity is likely to be mediated by P2X purinoceptors. This acquired purinergic sensitivity may play an important functional role in the enhancement of ectopic discharges and exacerbation of pain upon sympathetic activation in the neuropathic pain state.

Adenosine Triphosphate↗

PubMed2001

Effect of pH and soybean cultivars on the quantitative analyses of soybean rhizobia populations.

Quantitative analyses of fast- and slow-growing soybean rhizobia populations in soils of four different provinces of China (Hubei, Shan Dong, Henan, and Xinjiang) have been carried out using the most probable number technique (MPN). All soils contained fast- (FSR) and slow-growing (SSR) soybean rhizobia. Asiatic and American soybean cultivars grown at acid, neutral and alkaline pH were used as trapping hosts for FSR and SSR strains. The estimated total indigenous soybean-rhizobia populations of the Xinjiang and Shan Dong soil samples greatly varied with the different soybean cultivars used. The soybean cultivar and the pH at which plants were grown also showed clear effects on the FSR/SSR rations isolated from nodules. Results of competition experiments between FSR and SSR strains supported the importance of the soybean cultivar and the pH on the outcome of competition for nodulation between FSR and SSR strains. In general, nodule occupancy by FSRs significantly increased at alkaline pH. Bacterial isolates from soybean cultivar Jing Dou 19 inoculated with Xinjiang soil nodulate cultivars Heinong 33 and Williams very poorly. Plasmid and lipopolysaccharide (LPS) profiles and PCR-RAPD analyses showed that cultivar Jing Dou 19 had trapped a diversity of FSR strains. Most of the isolates from soybean cultivar Heinong 33 inoculated with Xinjiang soil were able to nodulate Heinong 33 and Williams showed very similar, or identical, plasmid, LPS and PCR-RAPD profiles. All the strains isolated from Xinjiang province, regardless of the soybean cultivar used for trapping, showed similar nodulation factor (LCO) profiles as judged by thin layer chromatographic analyses. These results indicate that the existence of soybean rhizobia sub-populations showing marked cultivar specificity, can affect the estimation of total soybean rhizobia populations indigenous to the soil, and can also affect the diversity of soybean rhizobial strains isolated from soybean nodules.

China↗