Biomedical subjects

J Y Hu

Publications and source records attributed to J Y Hu.

At least 37 records · Page 2Linked to original sources

PubMed2003

Removal of MS2 bacteriophage using membrane technologies.

Removals of MS2 bacteriophage virus using different membrane materials under different operating pressures were investigated. The results obtained in this study suggested that a better log removal in terms of MS2 bacteriophage virus could be achieved using Polyamide RO membrane under the optimum operating pressure of 100 psi. It is further noted that variable MS2 influent concentration levels resulted in corresponding variable log removals of the bacteriophages by the Polyamide RO membrane. The presence of MS2 bacteriophage virus in the effluent could possibly be due to leakage of bacteriophages through the membranes structure. Investigations using SEM and AFM showed that there were gaps or pores present in the membrane structure which were sufficiently large for the MS2 viruses to pass through.

Bacteria, Anaerobic↗

PubMed2002

Investigation of assimilable organic carbon (AOC) and bacterial regrowth in drinking water distribution system.

This paper investigated the variation of assimilable organic carbon (AOC) concentrations in water from several typical water treatment plants and distribution systems in a northern city of China. It is concluded from this study that: (1) The AOC in most of the product water of the studied water treatment plants and the water from the associated distribution systems could not meet the biostability criteria of 50-100 microg/L. (2) Only 4% of the measured AOC concentrations were less than 100 microg/L. However, about half of the measured AOC values were less than 200 microg/L. (3) Better source water quality resulted in lower AOC concentrations. (4) The variation of AOC concentrations in distribution systems was affected by chlorine oxidation and bacterial activity: the former resulted in an increase of AOC value while the latter led to a reduction in AOC. (5) The variation of AOC concentration followed different patterns in different distribution systems or different seasons due to their respective operational characteristics. (6) Less than 30% of AOC could be removed by a conventional treatment process, whereas 30-60% with a maximum of 50-60% could be removed by granular activated carbon (GAC). (7) The observation via scanning electron microscope (SEM) on distribution pipe tubercle samples demonstrated that the pipe inner wall was not smooth and bacteria multiplied in the crevice as well as in the interior wall of distribution pipes.

Bacteria↗

PubMed2002

An investigation on biological stability of product water generated by lab-scale and pilot-scale distillation systems.

Lab-scale and pilot-scale distillation systems were assessed in this study and the effectiveness of the treatment processes on Assimilable Organic Carbon (AOC) removal was also investigated. Seawater as one of the alternative water sources was used as the feed water and the resulting product water was intended for industry use. Acidification, ion trapping and anti-scaling chemical dosing were adopted as the pre-treatment processes to the feed water before distillation for pilot-plant system. The AOC assay was used to evaluate the efficiencies of various unit processes for AOC removal. Heterotrophic Plate Counts (HPC) was adopted in conjunction with AOC to determine the biological stability of the water samples. It is noted that the distillation system was able to produce a product water with an acceptable AOC concentration of less than 20 micrograms acetate-C L-1. This would suggest that the distillation system was capable of delivering a biologically stable product water. The results from lab-scale system indicated that pretreatment such as acidification, chlorination and antiscalant would increase AOC, although this does not affect the general performance of distillation system.

Carbon↗

PubMed2002

Restoration of teeth with more-viscous glass ionomer cements following radiation-induced caries.

OBJECTIVE: To assess the suitability of more-viscous conventional restorative glass ionomer cements (GICs) in a high-caries risk group of patients. METHODS: Fifteen adult patients with radiation-induced caries were treated at a dental hospital by one dentist. Two encapsulated aesthetic GICs were used in each patient to restore 146 carious lesions in the exposed dentine and cementum of 93 teeth. The restorations were assessed directly over two years for their retention, secondary caries, anatomic form, marginal integrity, marginal discolouration, and surface texture. RESULTS: Both GICs were placed in similar sized cavities (P = 0.63). After two years, although 30.0% of Ketac-Molar Aplicap and 12.5% of Fuji IX GP restorations had been lost (P = 0.01), there were no instances of secondary caries. The remaining GICs showed ongoing marginal deterioration, but there were very few instances where this required the repair or replacement of the restorations. No restorations failed from surface erosion. CONCLUSIONS: In these high-caries risk patients the placement of more-viscous GICs appeared to prevent secondary caries, even when the restorations were subsequently lost.

Adult↗

PubMed2002

Packed bed columns for high rate nitrogen and carbon removals.

Two packed bed column (PB) systems, namely anoxic-anoxic and anoxic-oxic were investigated for treatment of wastewater containing high concentrations of nitrogen (N) and COD. The anoxic-anoxic PB removal rates 6.70 kg N/m3 x d and 26.02 kg COD/m3 x d, respectively. The responding removal rates of the anoxic-oxic PB system were 7.41 kg N/m3 and 28.00 kg COD/m3 x d, respectively. The N and COD removal efficiencies of anoxic anoxic PB system were in the range of 99.2-100% and 97.2-98.8%, respectively. The corresponding removal efficiencies of anoxic-oxic PB system were 97.5-100% and 98.6-99.4%, respectively. These findings showed that a PB system consisting of anoxic-oxic columns in series has a high capacity to remove nitrogenous and carbonaceous compounds even though the influent to the anoxic stage was oxygenated. Better system stability in terms of denitrification was, however, obtained with the anoxic-anoxic system.

Bioreactors↗

PubMed2002

Toxicity assays to determine the start-up strategy for an anaerobic sequencing batch reactor (anSBR).

Addition of glucose as the co-substrate and the use of a water-based polymer to enhance granulation were studied with the aim of shortening the start-up period of an anSBR (anerobic sequencing batch reactor) for high-strength industrial wastewater treatment. An initial start-up feed composition consisting of 70% sucrose and 30% industrial wastewater was favorable to reduce the start-up time. Increase in the average particle size and reduction in settled supernatant turbidity was observed with increased water-based polymer addition up to a concentration of 0.1 m/L. Polymer dosages above 0.1 ml/L were undesirable as big and "flaky" flocs were formed which prevented the flocs from settling quickly. Addition of 0.005 ml/L to 0.1 ml/L polymer to the mixed liquor had no observable adverse effects on the anaerobic biomass metabolism. Instead, the addition of the polymer appeared to improve biogas production and had an overall positive effect on anSBR performance treating the industrial wastewater.

Bacteria, Anaerobic↗

PubMed2001

Fermentation of starch for enhanced alkaline protease production by constructing an alkalophilic Bacillus pumilus strain.

A new engineering strain, Bacillus pumilus c172-14 (pBX 96), was obtained by introducing the pBX 96 plasmid, which carries the alpha-amylase amy gene, into the host strain of alkalophilic Bacillus pumilus c172 via transformation. The newly constructed strain was found to express the amy gene and could use starch instead of glucose or starch hydrolysate as carbon source for its fermentation of alkaline protease. The pBX 96 plasmid in the new host was found to be segregationally and structurally stable. The expression of amy gene did not affect the host strain's resistance to bacteriophages. Moreover, the level of alkaline protease was improved significantly compared with the parent strain. The constructed strain gave a maximum alkaline protease activity of 14,014 U/ml in shaking flask after 48 h cultivation when growing in a medium containing 6% corn meal, 4% soybean flour, 0.4% Na2HPO4, 0.03% KH2PO4, 0.02% MgCl2, 0.3% CaCl2, 0.25% Na2CO3, 0.1% glucose, and 20 microg/ml kanamycin (pH 7.0). The optimal pH value and temperature of the alkaline protease were 11.0 and 40 degrees C, respectively. This enzyme was stable over a pH range of 8-11. Its residual activity remained at 100% when treated under a temperature of less than 45 degrees C for 30 min. The corresponding residual activity reduced to 65% of its optimal value at 60 degrees C for 30 min. The alkaline protease was a kind of serine protease, which was demonstrated by the complete inactivation by PMSF (1 mM). This newly constructed strain will be useful in the alkaline protease industry.

Bacillus↗

PubMed2001

Differential contributions of NMDA and non-NMDA receptors to spinal Fos expression evoked by superficial tissue and muscle inflammation in the rat.

The role of N-methyl-D-aspartate (NMDA) and non-NMDA receptors in the spinal cord in the transmission of nociceptive afferents from superficial tissue and muscle was studied by examining the effects of NMDA or non-NMDA receptor antagonists on Fos expression in the spinal dorsal horn. Muscle inflammation was induced by injection of turpentine oil into the gastrocnemius muscle, whereas superficial tissue inflammation was induced by an intraplantar injection of turpentine oil into the hindpaw. The NMDA receptor antagonist DL-2-amino-5-phosphonovaleric acid (AP-5), the non-NMDA receptor antagonist 6,7-dinitroquinoxaline-2,3-dione (DNQX) or normal saline were intrathecally administered 15 min before an intramuscular or intraplantar injection of turpentine oil. Muscle inflammation evoked expression of Fos-like immunoreactive neurons staining in neurons that were predominantly distributed in the middle portions of laminae I-II(outer) and the lateral portions of laminae V-VI of the ipsilateral dorsal horn at the spinal L(4)-L(5). DNQX, but not AP-5, significantly reduced the total number of Fos-like immunoreactive neurons evoked by muscle inflammation. In contrast, superficial tissue inflammation evoked expression of Fos-like immunoreactive neurons in the medial portions of laminae I-II(outer) and V-VI of the ipsilateral dorsal horn at the spinal L(4)-L(5) that was blocked by AP-5, but not by DNQX. Injection of normal saline did not influence the numbers of Fos-LI neurons. These results indicate that different glutamate receptors in the dorsal horn of the spinal cord may mediate nociceptive input from superficial tissue (particularly skin) and muscle. DNQX receptors may mediate transmission of nociceptive information originating in muscle, while NMDA receptors may preferentially mediate transmission of nociceptive information originating in skin.

Afferent Pathways↗

PubMed2001

Denitrifying phosphorus removal by anaerobic/anoxic sequencing batch reactor.

Denitrifying phosphorus removal was verified in a laboratory anaerobic/anoxic Sequencing Batch Reactor (A/A SBR) for a period of 18 months. The results obtained demonstrated the ability of the anaerobic/anoxic strategy to enrich the growth of denitrifying phosphorus bacteria (DPB) capable of taking up phosphate under anoxic conditions by using nitrate as the electron acceptor. Phosphorus removal efficiency ranging from 40-100% could be attained in an A/A SBR system. Simultaneous anoxic phosphate uptake and biological denitrification under anaerobic/anoxic condition occurred in this system. Batch tests showed, however, that simultaneous presence of carbon and nitrate would be detrimental to denitrifying phosphorus removal. Results of bacteria studies suggested that three denitrifying isolates had aerobic phosphorus removing ability.

Anaerobiosis↗

PubMed2001

Synthetic peptide MMK-1 is a highly specific chemotactic agonist for leukocyte FPRL1.

Human phagocytic leukocytes express the seven-transmembrane G-protein-coupled receptors formyl peptide receptor (FPR) and FPR-like 1 (FPRL1). MMK-1, a synthetic peptide derived from a random peptide library, is reported to induce calcium mobilization specifically in human FPRL1 gene-transfected cells. However, its actions on human phagocytic leukocytes remain poorly defined. We found that MMK-1 is a potent chemotactic and calcium-mobilizing agonist for human monocytes, neutrophils, and FPRL1-transfected human embryonic kidney (HEK) 293 cells but is inactive in cells transfected with FPR. MMK-1 also activated HEK 293 cells transfected with FPR2, a mouse counterpart of human FPRL1. Furthermore, MMK-1 increased pertussis toxin-sensitive production of inflammatory cytokines in human monocytes. MMK-1 signaling in human phagocytes was completely desensitized by a well-defined FPRL1 agonist, suggesting that FPRL1 is likely a receptor that mediates the action of MMK-1 in primary cells. Since MMK-1 is one of the most potent FPRL1-specific agonists identified so far, it can serve as a modulator of the host defense and a useful agent for further studying the signaling and function of FPRL1.

Animals↗

PubMed2001

The effects of water reclamation technologies on biological stability of industrial water.

A modified Assimilable Organic Carbon (AOC) procedure was adopted in conjunction with Heterotrophic Plate Count (HPC) method to assess the effect of Single Effect Distillation (SED) and Reverse Osmosis (RO) lab-scale systems on the biological stability of industrial water. Industrial water was collected from a local Industrial Water Works, pre-treated with alum coagulation and cartridge filtration, before being subjected to advanced water treatment. The results obtained in this study indicated that AOCs in the SED product water were in the range of 70-80 micrograms acetate-C/L, while those in the RO product water ranged from 30-40 micrograms acetate-C/L in the 15-min permeate to 55-65 micrograms acetate-C/L in the 3-hr permeate. The above findings suggested that product water of both systems were potentially biologically unstable and would likely lead to bacteria regrowth during its distribution and storage. Removal efficiencies of lab-scale RO and SED systems on AOC were as high as 90%, dependent on the concentration of AOC-NOX in the industrial water. The RO system had much higher organic removal efficiencies in terms of AOC and DOC than the SED system. Organics removed from both feed waters were found to be concentrated in the brine water and rejected water in SED and RO systems respectively.

Conservation of Natural Resources↗

PubMed2001

[Cloning and expression of human anti-colonic cancer single-chain Fv fragment].

We report a new strategy for the generation of human anticolon cancer monoclonal antibodies based on the molecular cloning and expression of immunoglobulin variable region cDNAs derived from peripheral blood mononuclear cells (PBMC) that were transformed by EBV. The immortalized B cells secreting tumor-specific antibodies were identified by HRT-18 cell ELISA and cloned by limiting dilution. Heavy- and light-chain VH-CH1 (gamma) and V kappa-C kappa cDNAs were rescued from ELISA-positive cells wells by RT-PCR. VH and V kappa were amplified by 2nd PCR and linked them together by 3rd PCR assembly with the use of a (Gly4Ser)3 linker. The ScFv cDNAs were then cloned into the fUSE 5 vector and displayed on phage. Phage clones were selected on HRT-18 cells and normal human PBMC. ELISA tested phage clones randomly picked after each panning step. > 80% of the clones showed a strong ELISA reaction, demonstrating the effectiveness of the panning procedure for selecting anticolon cancer antibodies. This approach offers an effective method by combining in vitro immunization, B-cell expansion for enrichment of specific B-lymphocytes, PCR gene cloning and phage display to make high-affinity human anticolon cancer monoclonal antibody molecules.

Antibodies, Monoclonal↗

PubMed2000

Endotoxin inducible transcription is repressed in endotoxin tolerant cells.

Stimulation of the human promonocytic cell line, THP-1, with endotoxin results in a rapid and transient increase in interleukin 1beta expression. Endotoxin pretreatment of THP-1 cells results in tolerance, characterized by decreased levels of endotoxin-induced interleukin 1beta expression due to decreased transcription of the interleukin 1beta gene. We hypothesized that tolerant cells could not activate transcription factors necessary to express the interleukin 1beta gene. This hypothesis was tested in tolerant THP-1 cells by using stable and transiently transfected reporter genes containing the interleukin 1beta promoter. We found decreased endotoxin-induced transcription of all reporter genes tested; however, individual transcription factors, such as NFkappaB, retain normal, CD14-dependent, nuclear translocation and DNA binding. Tolerance is specific for endotoxin, because phorbol ester is still able to activate transcription of the endogenous interleukin 1beta gene and transfected reporter genes. A constitutively active reporter gene that is not inducible by endotoxin is unaffected. We further show that nuclear extracts of tolerant cells show transcription inhibitor activity that is specific for promoter sequences of the interleukin 1beta gene. These results support a mechanism of endotoxin tolerance that is independent of transcription factor DNA binding and appears to be associated with the inability of DNA-bound transcription factors to activate transcription, perhaps through the activity of a repressor.

Bacterial Proteins↗

PubMed2000

Arcuate nucleus of hypothalamus involved in analgesic action of l-THP.

AIM: To study the role of the arcuate nucleus of hypothalamus in analgesic action of l-tetrahydropalmatine (l-THP). METHODS: The horseradish peroxidase (HRP) retrograde tracing, HRP retrograde tracing combined with immunohistochemistry, lesion of nucleus, tail-flick test, and intra-PAG injection were used in the present study. RESULTS: HRP retrograde tracing results showed that the striatum or accumbens nucleus connect with PAG by two pathways: 1) striatum or accumbens nucleus-->arcuate nucleus-->PAG; 2) striatum or accumbens nucleus-->habenula-->PAG. It was found that neurons in the arcuate nucleus projecting to PAG were mainly beta-endorphin neurons as observed by HRP retrograde tracing combined with immuno-histochemistry. After lesion of the arcuate nucleus, the analgesic action of l-THP (40 mg.kg-1, i.p.) was abolished, while lesion of the habenula had no such effect. Moreover, intra-PAG injection of naloxone (2, 3 micrograms) could markedly attenuate the analgesic action of l-THP (40 mg.kg-1, i.p.) in a dose-dependent manner. CONCLUSION: beta-Endorphin neurons in the arcuate nucleus play an important role in the analgesic action of l-THP.

Analgesics, Non-Narcotic↗

PubMed1999

Effect of tetrahydropalmatine analogs on Fos expression induced by formalin-pain.

AIM: To study the effect of tetrahydropalmatine (THP) analogs on Fos protein expression induced by formalin-pain and elucidate analgesic mechanism of THP analogs. METHODS: The pain response to Sprague Dawley rats was induced with formalin injected s.c. into the plantar surface of the right hindpaw. Fos protein expression in brain and spinal cord was investigated with immunohistochemistry. The numbers of Fos-like immunoreactive (FLI) neurons were counted with Leica Q570 image analyzer. RESULTS: In the groups of THP analogs and D2 antagonist spiperone, FLI neurons induced by intraperitoneal (i.p.) injection of THP analogs and spiperone were mainly located in the striatum and accumbens nucleus, and a few FLI neurons were also in sensorimotor cortex. In the D1 antagonist, D1 agonist, D2 agonist, saline and vehicle groups, FLI neurons were seldom seen in the striatum and accumbens nucleus. Moreover, the Fos protein expression induced by l-THP and spiperone could be prevented by the pre-treatment of the D2 agonist quinpirole but not D1 agonist SKF38393. In the formalin-pain group, FLI neurons were mainly distributed in ascending pain afferent system (APAS) and descending pain modulation system (DPMS). Following i.p. THP analogs, however, the numbers of FLI neurons induced by formalin-pain in the APAS, such as dorsal horn (mainly laminae I, II, IV-VI) were markedly decreased, while the numbers of FLI neurons in the DPMS, such as periaqueductal gray (PAG) and reticular paragigantocellular lateral nucleus (RPLN) were significantly increased. CONCLUSION: THP analogs enhanced the activity of brainstem DPMS by the blockade of D2 receptors in the striatum and accumbens nucleus, and sequentially inhibited the inputs of peripheral pain afferent message in spinal cord level.

Analgesics, Non-Narcotic↗

PubMed1999

Supraspinal D2 receptor involved in antinociception induced by l-tetrahydropalmatine.

AIM: To study the role of dopamine (DA) receptors in l-tetrahydropalmatine (l-THP)-induced antinociception. METHODS: The intraperitoneal (i.p.) and intrathecal (ith) injections were used to give the drugs. The tail-flick test was used to assess the nociceptive threshold of rats. RESULTS: By i.p. injection, l-THP (10, 20, 40 mg.kg-1) as well as D2 receptor antagonist spiperone (1, 2, 3 mg.kg-1) produced dose-dependent antinociceptive effects on the nociception of rats, while D2 receptor agonist quinpirole, D1 receptor agonist SKF38393, and D1 receptor antagonist Sch-23390 showed no antinociception. Moreover, l-THP- or spiperone-induced antinociception was markedly attenuated by quinpirole (2, 3 mg.kg-1) but not SKF38393 or naloxone. On the other hand, ith quinpirole (20, 30, 40 micrograms.kg-1) also induced a dose-dependent antinociception, while ith l-THP, spiperone, SKF38393, and Sch-23390 did not exhibit any antinociception. Furthermore, ith spiperone (20, 30, 40 micrograms.kg-1) but not Sch-23390 dose-dependently antagonised the antinociception induced by quinpirole. l-THP (ith, 100, 200, 300 micrograms.kg-1) also dramatically attenuated the quinpirole-induced antinociception with a dose-dependent relationship. CONCLUSION: Activating the spinal D2 receptor or blocking the supraspinal D2 receptor produces antinociception. D1 receptor might be not directly involved in the antinociception. l-THP (as a D2 antagonist) as well as spiperone produces antinociception via blocking the supraspinal D2 receptor.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

PubMed1998

Involvement of dopamine D1 and D2 receptors in Fos immunoreactivity induced by stepholidine in both intact and denervated striatum of lesioned rats.

Stepholidine (SPD), a natural product, has been demonstrated in previous studies as a D1 agonist and D2 antagonist. In this work SPD-induced Fos immunoreactivity was examined. In the normal rats, Fos was induced in the striatum by SPD (1-20 mg/kg, i.p.) dose-dependently. The distribution of Fos-positive cells induced by SPD showed a rostral-caudal decline, matching the distribution of D2 dopamine receptors. The Fos-positive cells were mainly found in striatal neurons retrogradely labeled with horseradish peroxidase (HRP) from GP but not from SN, and could be abolished by the pretreatment of a D2 agonist LY171555 (2 mg/kg, i.p.), suggesting that the Fos expression in normal rats was due to the D2 antagonistic action of SPD. In the unilateral 6-hydroxydopamine-lesioned rats, SPD (4 mg/kg, i.p.) induced Fos expression in intact and denervated side of the striatum with different characteristics. Similar to that of normal rats, the Fos expression in intact side possessed the rostral-caudal gradient and could be abolished by the pretreatment of LY171555. However, in the denervated side, the Fos positive cells were widely distributed, and mainly found in striatal neurons retrogradely labeled from SN but not from GP. Furthermore, this expression was prevented by the pretreatment of SCH23390 (0.2 mg/kg, i.p.) but not LY171555, suggesting that the Fos expression in denervated side was due to the D1 agonistic action of SPD. Therefore, we concluded that the Fos expression induced by SPD in intact and denervated striatum was mediated via D2 and D1 receptor respectively, supporting the previous standpoint that SPD possesses the dual action, i.e antagonist to D2 and agonist to D1 receptors. Furthermore, it is suggested that the contralateral turning behavior induced by SPD may result from the D1-mediated excitation of striatonigral neurons of the denervated side of the lesioned rats.

Animals↗

PubMed1997

RNA-RNA recombination in Sindbis virus: roles of the 3' conserved motif, poly(A) tail, and nonviral sequences of template RNAs in polymerase recognition and template switching.

Sindbis virus (SIN), a mosquito-transmitted animal RNA virus, carries a 11.7-kb positive-sense RNA genome which is capped and polyadenylated. We recently reported that the SIN RNA-dependent RNA polymerase (RdRp) could initiate negative-strand RNA synthesis from a 0.3-kb 3'-coterminal SIN RNA fragment and undergo template switching in vivo (M. Hajjou, K. R. Hill, S. V. Subramaniam, J. Y. Hu, and R. Raju, J. Virol. 70:5153-5164, 1996). To identify and characterize the viral and nonviral sequences which regulate SIN RNA synthesis and recombination, a series of SIN RNAs carrying altered 3' ends were tested for the ability to produce infectious virus or to support recombination in BHK cells. The major findings of this report are as follows: (i) the 3'-terminal 20-nucleotides (nt) sequence along with the abutting poly(A) tail of the SIN genome fully supports negative-strand synthesis, genome replication, and template switching; (ii) a full-length SIN RNA carrying the 3'-terminal 24 nt but lacking the poly(A) tail is noninfectious; (iii) SIN RNAs which carry 3' 64 nt or more without the poly(A) tail are infectious and regain their poly(A) tail in vivo; (iv) donor templates lacking the poly(A) tail do not support template switching; (v) full-length SIN RNAs lacking the poly(A) tail but carrying 3' nonviral extensions, although debilitated to begin with, evolve into rapidly growing poly(A)-carrying mutants; (vi) poly(A) or poly(U) motifs positioned internally within the acceptor templates, in the absence of other promoter elements within the vicinity, do not induce the jumping polymerase to reinitiate at these sites; and (vii) the junction site selection on donor templates occurs independently of the sequences around the acceptor sites. In addition to furthering our understanding of RNA recombination, these studies give interesting clues as to how the alphavirus polymerase interacts with its 3' promoter elements of genomic RNA and nonreplicative RNAs. This is the first report that an in vitro-synthesized alphavirus RNA lacking a poly(A) tail can initiate infection and produce 3' polyadenylated viral genome in vivo.

Animals↗