Biomedical subjects

B Wang

Publications and source records attributed to B Wang.

At least 55 records · Page 3Linked to original sources

PubMed2005

Performance of a combined eco-system of ponds and constructed wetlands for wastewater reclamation and reuse.

An on-site study on the operational performance of a combined eco-system of ponds and SF constructed wetland for municipal wastewater treatment and reclamation/reuse in Donging City, Shandong, China was carried out from January 2001 through October 2003. The removal efficiencies for various main parameters were: TSS 84.8 +/- 7.3%, BOD5 87.2 +/- 5.3%, CODCr 70.2 +/- 18.6%, TP 52.3 +/- 23.1%, and NH(3)-N 54.8 +/- 23.9% with effluent concentration of TSS 9.12 +/- 5.12 mg/l, BOD5 6.44 +/- 4.58 mg/l, CODCr, 42.8 +/- 6.7 mg/l, TP 0.94 +/- 0.27 mg/l and NH(3)-N 7.95 +/- 2.36 mg/l. In addition, the removal efficiencies for faecal coliforms and total bacteria were > 99.97% and > 99.998% respectively, which well meet Chinese National standards for effluent quality of municipal wastewater treatment plants. The composition of TSS was closely related to CODCr and BOD5 variations, and nitrification-denitrification is the major mechanism of nitrogen removal both in ponds and in wetlands. In addition, sedimentation also played an important role in the removal of TSS, nitrogen, phosphorus and BOD5. The removal efficiencies of various parameters, the number of species and biomass of biological community in the system increased gradually with the ecological maturation.

Ammonia↗

PubMed2005

Municipal wastewater treatment with pond-constructed wetland system: a case study.

The performance of a pond-constructed wetland system in the treatment of municipal wastewater in Kiaochow city was studied; and comparison with oxidation ponds system was conducted. In the post-constructed wetland, the removal of COD, TN and TP is 24%, 58.5% and 24.8% respectively. The treated effluent from the constructed wetland can meet the Chinese National Agricultural and Irrigation Standard. The comparison between pond-constructed wetland system and oxidation pond system shows that total nitrogen removal in a constructed wetland is better than that in an oxidation pond and the TP removal is inferior. A possible reason is the low dissolved oxygen concentration in the wetland. Constructed wetlands can restrain the growth of algae effectively, and can produce obvious ecological and economical benefits.

China↗

PubMed2005

Performance improvement of hybrid membrane bioreactor with PAC addition for water reuse.

A study was carried out on a hybrid (AS-SBF) membrane bioreactor (HMBR) for the municipal wastewater reclamation and reuse at Chengfengzhuang WWTP in Daqing City, Heilongjiang Province. It was found that the effects of DO and water temperature on performance of the HMBR was significant. Under the conditions of water temperature in range of 10-14 degrees C, pH of 6.6- 7.0, DO of 4-6 mg/l and HRT of 7 h, the HMBR exhibited removal efficiencies for CODcr, BOD5, NH3-N and TN of 96.7%, 98.9%, 93.7% and 60.5% respectively. The turbidity of effluent from HMBR was below 1 NTU. The effluent of HMBR meets the standard of wastewater reclamation for oil exploitation. PAC was added into the bioreactor at the second operating stage, in order to further research parameters variation. The flux was improved by 53.2%, compared to the membrane without PAC-addition, due to formation of a PAC pre-coat layer on the membrane surface, with lots of advantages such as larger granules, higher porosity, non-compressibility, higher filterability and easy removal, compared with pure biomass layer. In addition, the performance of HMBR was further improved, due to adsorption and degradation of SMPs, the average removal of CODcr and TN was further improved by 5.1% and 13.5% respectively. Biomass in the HMBR was quantitatively measured, of which the biofilm played a major role in pollutants removal.

Ammonia↗

PubMed2005

Simultaneous nitrification and de-nitrification in MBR.

Experiments have been carried out to get an understanding of the effect of DO, C/N ratio and pH on the performance of a bench scale membrane bioreactor (MBR) in simultaneous nitrification and denitrification. It was found that under the conditions of MLSS in the range of 8000-9000 mg/L and temperature of water in the MBR of 24 degrees C, influent COD and NH3-N in the range of 523-700 mg/L and 17.24-24 mg/L respectively, the removals of COD, NH3-N and TN were 98%, 99% and 60%; 96.5%, 0,98% and 75%; 96%, 95% and 92%; 90%,70% and 60% respectively at DO of 6, 3, 1 and 0.5 mg/L. It was also found that the changes in C/N ratio and pH in a certain range have a slight effect on COD removal but have significant influence on the removal of NH3-N and TN. The results showed that only under the conditions that each ecological factor was maintained relatively steadily, simultaneous nitrification and de-nitrification proceeded smoothly. It was found that when C/N ratio was 30, the influent pH 7.2, the temperature of water in MBR 24 degrees C and DO 1 mg/L, as optimum conditions, the removals of COD, NH3-N and TN were 96%, 95% and 92% respectively. In addition, mechanism research on simultaneous nitrification and de-nitrification in MBR has been conducted as well.

Ammonia↗

PubMed2004

Dynamics of {beta}-amyloid reductions in brain, cerebrospinal fluid, and plasma of {beta}-amyloid precursor protein transgenic mice treated with a {gamma}-secretase inhibitor.

gamma-Secretase inhibitors are one promising approach to the development of a therapeutic for Alzheimer's disease (AD). gamma-Secretase inhibitors reduce brain beta-amyloid peptide (Abeta), which is believed to be a major contributor in the etiology of AD. Transgenic mice overexpressing the human beta-amyloid precursor protein (APP) are valuable models to examine the dynamics of Abeta changes with gamma-secretase inhibitors in plaque-free and plaque-bearing animals. BMS-299897 2-[(1R)-1-[[(4-chlorophenyl)sulfony](2,5-difluorophenyl)amino]ethyl]-5-fluorobenzenepropanoic acid, a gamma-secretase inhibitor, showed dose- and time dependent reductions of Abeta in brain, cerebrospinal fluid (CSF), and plasma in young transgenic mice, with a significant correlation between brain and CSF Abeta levels. Because CSF and brain interstitial fluid are distinct compartments in composition and location, this correlation could not be assumed. In contrast, aged transgenic mice with large accumulations of Abeta in plaques showed reductions in CSF Abeta in the absence of measurable changes in plaque Abeta in the brain after up to 2 weeks of treatment. Hence, CSF Abeta levels were a valuable measure of gamma-secretase activity in the central nervous system in either the presence or absence of plaques. Transgenic mice were also used to examine potential side effects due to Notch inhibition. BMS-299897 was 15-fold more effective at preventing the cleavage of APP than of Notch in vitro. No changes in the maturation of CD8(+) thymocytes or of intestinal goblet cells were observed in mice treated with BMS-299897, showing that it is possible for gamma-secretase inhibitors to reduce brain Abeta without causing Notch-mediated toxicity.

Aging↗

PubMed2004

Triptolide, an active component of the Chinese herbal remedy Tripterygium wilfordii Hook F, inhibits production of nitric oxide by decreasing inducible nitric oxide synthase gene transcription.

OBJECTIVE: The ethyl acetate (EA) extract of Tripterygium wilfordii Hook F (TWHF) and its major active component, triptolide, have been reported to be effective in the treatment of rheumatoid arthritis and other autoimmune inflammatory diseases. Nitric oxide (NO) has been recognized as an important mediator of inflammation. This study was therefore undertaken to examine the effects of the EA extract and triptolide on the production of NO and inducible NO synthase (iNOS) gene expression and transcription in vivo and in vitro. METHODS: Peritoneal macrophages from C57BL/6J mice treated orally with the EA extract of TWHF were assayed for NO production and iNOS messenger RNA (mRNA) expression by reverse transcriptase-polymerase chain reaction. The murine fibroblast cell line NIH3T3 was also assessed for NO production and iNOS mRNA expression, as well as for iNOS promoter activation, Oct-1 nuclear binding capacity, and Oct-1 protein content by transient transfection, electrophoretic mobility shift assay, and immunoblotting, respectively. RESULTS: NO production and iNOS mRNA expression by macrophages from C57BL/6J mice immunized with trinitrophenyl-bovine serum albumin in Freund's complete adjuvant were significantly inhibited by oral administration of the EA extract (52.3% and 59.8% of control, respectively, at one-eighth of the dose that is lethal for 50% of the animals [LD(50)] and 21.0% and 38.1% of control, respectively, at one-fourth the LD(50)). Moreover, the EA extract and triptolide significantly inhibited NO production in vitro in activated peritoneal macrophages, which reflected a decreased level of iNOS mRNA. Finally, triptolide inhibited promoter activity of the iNOS gene and induction of the activity of the regulator of iNOS transcription, Oct-1. CONCLUSION: The EA extract of TWHF and triptolide inhibit transcription of the iNOS gene. This may contribute to the antiinflammatory effects of this traditional herbal remedy.

Animals↗

PubMed2004

Expression of sigma 1 receptor in human breast cancer.

The sigma 1 receptor (S1R) represents a unique drug-binding site that is distinct from any other receptors. We examined S1R expression in human breast cancer and assessed the activity of S1R ligands in breast cancer cell lines. One-hundred nine breast specimens from normal breast, benign breast disease and cancer were examined with immunohistochemistry or RT-PCR and six different cell lines were also evaluated. S1R mRNA overexpression was detected in 64% of breast cancers compared to normal breast tissue. Immunohistochemistry showed positive epithelial cell staining in 60% of invasive and 41% of in situ cancers, 75% of ductal hyperplasia and in 33% of normal breast. The pattern of expression was more diffuse in invasive breast carcinoma compared to other conditions (p = 0.02). S1R expression was neither a prognostic nor a predictive factor for efficacy of adjuvant chemotherapy but the study only included 58 cancer patients and therefore the statistical power is limited. MDA-MB-361, MDA-MB-435, BT20 and MCF7 cells all expressed S1R protein by Western blot. The non-specific S1R ligands haloperidol, reduced haloperidol and progesterone produced a dose-dependent inhibition of the growth at high (>10 microM) concentrations. Reduced haloperidol also showed additive cytotoxic effects when combined with doxorubicin, vinorelbine , paclitaxel and docetaxel in vitro. The S1R-specific ligand, SKF 10047 demonstrated the least growth inhibitory activity and showed no interaction with chemotherapy. These results demonstrate that some normal and most neoplastic breast epithelial cells and cell lines commonly express S1R. High concentrations of haloperidol inhibit the growth of these cells and potentiate the effect of chemotherapy in vitro.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2004

New acridone derivatives for the electrochemical DNA-hybridisation labelling.

In the field of DNA sensing, DNA hybridisation detection is generally performed by fluorescence microscopy. However, fluorescence instrumentation is difficult to miniaturise in order to produce fully integrated DNA chips. In this context, electrochemical detection of DNA hybridisation may avoid this limitation. Therefore, the use of DNA intercalators is particularly attractive due to their selectivity toward DNA double strand enabling DNA labelling without target chemical modification and, for most of them, to their electroactivity. We have synthesized a pyridoacridone derivative dedicated to DNA hybridisation electrochemical-sensing which presents good electrochemical reversibility, electroactivity at mild potentials and specificity toward DNA double strand. The electrochemical behaviour of this molecule has been assessed using cyclic voltammetry (CV). DNA/intercalator interactions were studied by differential pulse voltammetry (DPV) before application to hybridisation detection onto DNA sensors based on polypyrrole modified electrodes.

Acridines↗

PubMed2004

The effect of aging and caloric restriction on mitochondrial protein density and oxygen consumption.

It has been proposed that part of the anti-aging mechanism of caloric restriction (CR) involves changes in mitochondrial function. To investigate this hypothesis, mitochondria from various tissues of male Brown Norway rats (fully fed and CR) were isolated and respiration rates determined. In mitochondria from liver, heart, brain and kidney, there were no significant effects of CR on state 4 mitochondrial respiration rate. Further experiments using liver mitochondria under a variety of incubation conditions confirmed that CR does not alter mitochondrial respiration rate in this tissue. However, the respiration rate of mitochondria from brown adipose tissue (BAT) of CR animals was approximately three-fold higher compared to mitochondria from fully fed controls. Mitochondrial protein density was significantly higher in liver tissue of CR animals; it was significantly lower in heart and unchanged in BAT. It is concluded that whilst CR results in tissue-specific changes in mitochondrial respiration rate, these effects do not explain the CR-induced changes in free radical production reported previously for these organelles.

Aging↗

PubMed2004

Microarray analysis of UVB-regulated genes in keratinocytes: downregulation of angiogenesis inhibitor thrombospondin-1.

BACKGROUND: Ultraviolet (UV) B light is an environmental mutagen that induces changes in cutaneous gene expression leading to immune suppression and carcinogenesis. Keratinocytes are a primary target for UVB. OBJECTIVE: To further delineate UVB-induced gene expression changes in keratinocytes. METHODS: cDNA microarray technology was utilized to examine gene expression in normal human KC (NHKC) following 20 mJcm(-2) UVB irradiation. Data was confirmed by semi-quantitative RT-PCR. RESULTS: Microarray analysis revealed 57 genes were upregulated, and 27 genes were downregulated, by at least two-fold following UVB. One downregulated gene was the endogenous angiogenesis inhibitor thrombospondin-1 (TSP-1). Semi-quantitative RT-PCR confirmed persistent downregulation of TSP-1 up to 18h following UVB. Microarray analysis also revealed upregulation of platelet-derived endothelial cell growth factor (PD-ECGF)--an angiogenesis activator. CONCLUSION: Our results suggest a gene expression mechanism by which UVB induces an angiogenic switch in keratinocytes. This may represent an important early event promoting neovascularization and growth of cutaneous neoplasms.

Cells, Cultured↗

PubMed2004

Cocaine-induced Fos expression in rat striatum is blocked by chloral hydrate or urethane.

Anesthetics used in electrophysiological studies alter the effects of cocaine and amphetamine on neural activity in the striatum. However, the mechanism underlying this alteration has not been established. In the present study, we examined the effects of anesthetics on cocaine-induced neural activity in the striatum. We first assayed the ability of 20 mg/kg cocaine to induce Fos expression in the striatum following pretreatment with 400 mg/kg chloral hydrate or 1.3 g/kg urethane, two of the most commonly used anesthetics for in vivo electrophysiology. Chloral hydrate blocked, while urethane strongly attenuated cocaine-induced Fos expression without affecting basal levels of expression. We then examined dopaminergic and glutamatergic mechanisms for anesthetic effects on cocaine-induced Fos expression. Chloral hydrate and urethane did not attenuate basal or cocaine-induced increases of dopamine levels as assessed by microdialysis in dorsal striatum. In contrast, chloral hydrate attenuated glutamatergic neurotransmission as assessed by microdialysis in the presence of the glutamate transport blocker L-trans-pyrrolidone-2,4-dicarboxylic acid. Chloral hydrate attenuated basal levels of glutamate by 70%, while cocaine had no effect on glutamate levels. Since glutamate levels were tetrodotoxin-sensitive, the majority of glutamate measured in our assay was by synaptic release. To assess a causal role for a reduction of glutamatergic neurotransmission in anesthetic effects on cocaine-induced Fos expression, we injected the glutamate receptor agonists AMPA and NMDA into the dorsal striatum of chloral hydrate-anesthetized rats. The glutamate receptor agonists partially reinstated cocaine-induced Fos expression in anesthetized rats. We conclude anesthetics attenuate cocaine-induced neuronal activity by reducing glutamatergic neurotransmission.

Amino Acid Transport System X-AG↗

PubMed2004

State of the art in the production of transgenic goats.

This review summarises recent advances in the field of transgenic goats for the purpose of producing recombinant proteins in their milk. Production of transgenic goats via pronuclear microinjection of DNA expression vectors has been the traditional method, but this results in low efficiencies. Somatic cell nuclear transfer has dramatically improved efficiencies in rates of transgenesis. Characterisation of transfected cells in vitro before use in nuclear transfer guarantees that kids born are transgenic and of predetermined gender. Using these platform technologies, several recombinant proteins of commercial interest have been produced, although none of them has yet gained marketing approval. Before these technologies are implemented in goat improvement programmes, efficiencies must be improved, costs reduced, and regulatory approval obtained for the marketing of food products derived from such animals.

Animals↗

PubMed2004

Asparaginase pharmacodynamics differ by formulation among children with newly diagnosed acute lymphoblastic leukemia.

Polyethylene glycol-conjugated (PEG) asparaginase is approved for use in patients who develop allergy to other forms of asparaginase, although its ability to deplete asparagine systemically in patients with hypersensitivity has not been well elucidated. In 53 children with newly diagnosed acute lymphoblastic leukemia, we serially assessed asparagine concentrations in cerebrospinal fluid (CSF) and plasma as well as serum anti-asparaginase antibodies. All patients received native Escherichia coli (Elspar) asparaginase during induction therapy; patients received PEG asparaginase during reinductions when available, and those who developed allergy received Erwinia asparaginase. All eight patients who developed clinical evidence of allergy to asparaginase had anti-asparaginase antibodies. Among patients who had no antibodies, those who received E. coli had lower mean (+/-s.d.) CSF asparagine (0.29+/-0.63, n=9) than those who received PEG (0.77+/-0.82, n=4) (P=0.007). Results were similar for plasma asparagine. There was no situation where asparagine concentrations were more effectively depleted by PEG than by other preparations. None of the five patients who developed thrombosis had an allergy or antibodies to asparaginase at the time of the thrombosis. We conclude that asparagine concentrations were less effectively depleted by PEG than by E. coli asparaginase at the doses commonly used. The risk of thrombosis may be affected by the intensity of asparaginase exposure.

Antibodies↗

PubMed2004

Effects of repetition, interval between treatments and season on the results from laparoscopic ovum pick-up in goats.

The present study was conducted to evaluate the follicular response and oocyte yield following repeated gonadotrophin stimulation and laparoscopic aspiration in goats and to assess the effects of the time interval between procedures and season. A total of 98 adult goats were subjected to laparoscopic ovum pick-up (LOPU) five consecutive times in a transgenic production programme. Oestrus was synchronised by means of intravaginal sponges inserted for 10 days coupled with 125 microg cloprostenol 36 h before sponge removal and LOPU, and follicular development was stimulated with 80 mg follicle stimulating hormone and 300 IU equine chorionic gonadotrophin administered 36 h before LOPU. No difference was detected in the response for LOPUs 1, 2, 3 and 4. Although a small decrease in response was detected at LOPU 5 (P < 0.05), the numbers of follicles aspirated and oocytes recovered were not different from those at LOPU 1 and LOPUs 1 and 4, respectively. With respect to time interval between LOPU and season, all intervals and seasons produced acceptable responses, with no difference in follicles aspirated and oocytes recovered between intervals and seasons. These results indicate that LOPU may be repeated up to five times in goats at different intervals and in different seasons with little or no important change in overall response.

Animals↗

PubMed2004

Prepubertal propagation of transgenic cloned goats by laparoscopic ovum pick-up and in vitro embryo production.

The use of laparoscopic ovum pick-up (LOPU) followed by in vitro embryo production was evaluated in the early propagation of cloned goats. Ten kinder goats produced by somatic cell nuclear transfer technology were used as oocyte donors. Half of the donor animals were subjected to LOPU at 2-3 months of age (prior to induction of lactation), whereas the other five goats were subjected to LOPU at 6-7 months of age (following induction to lactation). They were stimulated with 80 mg NIH-FSH-P1 (Folltropin, Vetrepharm, Canada) together with 300 IU eCG (Novormon, Vetrepharm, Canada) administered intramuscularly 36 h prior to LOPU. The number of follicles aspirated and oocytes recovered was higher in the younger group of donors (57 +/- 7 and 41 +/- 4 vs. 28 +/- 2 and 25.8 +/- 2, p < 0.05), however, oocytes from animals in the late prepubertal age showed higher developmental capacity resulting in higher transferable embryo yield (81.4% vs. 67.8%, p < 0.01), pregnancy rate (80% vs. 40%, p < 0.05) and total kids born (27 vs. 15, p < 0.01). In conclusion, LOPU in combination with in vitro embryo production techniques is an efficient method for the early propagation of valuable goats produced by somatic cell nuclear transfer.

Animals↗

PubMed2004

Benzodioxocin-3-ones and N-acyl-3-amino-3-buten-2-ones: novel classes of cathepsin K cysteine protease inhibitors.

The design, synthesis, enzymologic, and protein mass spectrometric characterization of benzodioxocin-3-one and N-acyl-3-amino-3-buten-2-one inhibitors of the cysteine protease cathepsin K are described. The benzodioxocin-3-one ring system is chemically unstable giving rise to a mixture of N-acyl-3-amino-3-buten-2-one and hemiketals. This mixture of N-acyl-3-amino-3-buten-2-one and hemiketals potently inhibits recombinant, human cathepsin K (IC50 = 36 nM) by a time-independent, irreversible mechanism. Formation of a covalent adduct between cathepsin K and inhibitor has been confirmed by mass spectrometry.

Cathepsin K↗

PubMed2004

Comparison of demographic and donation profiles and transfusion-transmissible disease markers and risk rates in previously transfused and nontransfused blood donors.

BACKGROUND: Increasing concern about transfusion transmission of variant Creutzfeldt-Jakob disease has resulted in indefinite deferral of transfused donors in France and the UK. Little is known, however, about the impact of indefinite deferral of transfused donors on blood safety and availability in the US. STUDY DESIGN AND METHODS: Data were collected on allogeneic donations at five US blood centers during 1991 through 2000. Donation characteristics, prevalence, and incidence of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) were compared between transfused and nontransfused donors. Unreported deferrable risk (UDR) and reasons to donate were evaluated with data from a mail survey. RESULTS: Transfusion history was reported by 4.2 percent of donors. Prevalence and incidence of HIV and HBV were comparable between transfused and nontransfused donors. Although HCV incidence was similar in both groups, HCV prevalence was nearly three times higher in transfused than in nontransfused first-time donors. UDR and reasons to donate were similar in the two groups, except transfused donors were less likely to donate for screening test results (odds ratio, 0.5; 95% confidence interval, 0.3-0.8). CONCLUSION: Transfused and nontransfused donors had similar viral incidence and comparable UDR, suggesting that indefinite deferral of transfused donors would unlikely improve blood safety. Until more is known about the prevalence and transfusion transmissibility of emerging agents, indefinite deferral of previously transfused donors in the US does not appear warranted.

Adult↗

PubMed2003

Prevalence and clinical features of HTLV neurologic disease in the HTLV Outcomes Study.

BACKGROUND: Almost 20 years after its discovery, the prevalence and clinical course of human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM, also known as tropical spastic paraparesis [TSP]) remain poorly defined. Whereas the causative association of HTLV-I and HAM/TSP is generally recognized, controversy still surrounds the relationship between HTLV-II and HAM/TSP. METHODS: The HTLV Outcomes Study (HOST-formerly Retrovirus Epidemiology Donor Study [REDS]) is a prospective cohort study including 160 patients with HTLV-I, 405 patients with HTLV-II, and 799 uninfected controls who have been followed every 2 years since 1990-1992. Clinical outcomes are measured by health interviews and examinations, and blood samples are obtained. RESULTS: Six cases of HTLV-I-associated myelopathy (3.7%, 95% CI 1.4 to 8.0) and four cases of HTLV-II myelopathy (1.0%, 95% CI 0.3 to 2.5) have been diagnosed since the formation of the cohort. There have been no cases of HAM/TSP diagnosed among HTLV-negative subjects (0.0%, 95% CI 0.0 to 0.5). Clinical features of the cases include lower extremity hyperreflexia, variably associated with weakness, spasticity, and bladder dysfunction. CONCLUSIONS: Systematic screening of HTLV-infected blood donors reveals a high prevalence of HAM/TSP. The clinical course of HAM/TSP appears highly variable. HTLV-II-associated myelopathy generally presents with milder and more slowly progressive signs and symptoms.

Adolescent↗