Search PubMed⌕ Search

Biomedical subjects

F Lu

Publications and source records attributed to F Lu.

At least 37 records · Page 2Linked to original sources
PubMed2003

A new method for characterizing denitrifying phosphorus removal bacteria by using three different types of electron acceptors.

This study investigated the characteristics of denitrifying phosphorus removal bacteria by using three different types of electron acceptors as well as the positive role of nitrite in phosphorus removal process. Denitrifying phosphorous removal bacteria was enriched under anaerobic-anoxic (A/A) condition. To understand A/A sludge better, sludge from two other sources were also studied. These include sludges obtained from a lab-scale anaerobic-anoxic-aerobic (A/A/O) system and a local sewage treatment plant. Three types of possible electron acceptors (oxygen, nitrate and nitrite) were examined for their roles in phosphorus uptake. The results obtained indicated that oxygen, nitrate and nitrite were able to act as electron acceptors successfully. This observation suggested that in addition to the two well-accepted groups of phosphorus removal bacteria (one can only utilize oxygen to take up phosphorus, P(O), while the other can use both oxygen and nitrate, P(ON)), a new group of phosphorus removal bacteria, P(ON(n)), which could use oxygen, nitrate or nitrite to take up phosphorus was identified. The relative population of these three types of bacteria could be calculated from results obtainable from phosphorus uptake batch experiments with either oxygen or nitrate or nitrite as electron acceptor. The results obtained in this study showed that A/A sludge had similar phosphorus removal performance as the A/A/O sludge. However, it has better denitrifying phosphorus removal capability, which was demonstrated by the relative population of the three groups of bacteria. The results also suggested that nitrite was not an inhibitor to phosphorus removal process. Instead, it is an alternative electron acceptor to oxygen or nitrate.

Bacteria↗
PubMed2001

The role of protein kinase B (PKB) in modulating heat sensitivity in a human breast cancer cell line.

PURPOSE: Protein kinase B (PKB) is a critical mediator of phosphoinositide 3-kinase-dependent survival signals in mammalian cells. Its activity is induced after heat shock, and is inhibited in cells undergoing apoptosis. We hypothesized that PKB may be an important modulator for heat-induced apoptosis in human cancer cells. METHODS AND MATERIALS: MCF-7 cells were transfected using four different plasmids, encoding a kinase-dead mutant PKB-AAA, a constitutively activated mutant PKB-DD, wild-type PKB, and the neomycin-resistant selection gene. These stable transfectants were subjected to heat shock, and assessed for PKB phosphorylation, PKB activity, and likelihood of undergoing apoptosis. RESULTS: After heating to 45 degrees C x 30 mins, 25% of MCF-7/neo transfectants underwent apoptosis, which increased to 38% in the presence of wortmannin (WT), an inhibitor of phosphoinositide 3-kinase. In contrast, 23% of the constitutively activated MCF-7/DD transfectants underwent apoptosis, minimally affected by WT. Heat-induced apoptosis occurred in 34% of the kinase-dead MCF-7/AAA transfectants, which increased further to 58% with the addition of WT. This in turn was associated with a two-fold reduction in clonogenic survival compared to the MCF-7/neo transfectants. CONCLUSION: Heat shock activation of PKB in human MCF-7 cells appears to be a significant modulator of heat-induced apoptosis and survival. Further understanding of this important pathway may offer potential in developing novel strategies in cancer therapy.

Apoptosis↗
PubMed2001

[Mycophenolate mofetil in the treatment of primary nephrotic syndrome].

OBJECTIVE: To investigate the efficacy and safety of mycophenolate mofetil (MMF) on treating refractory primary nephrotic syndrome. METHODS: Forty-one patients with refractory nephrotic syndrome confirmed by renal biopsy, 19 with minor lesion (minimal lesion nephropathy and mesangial proliferative glomerulonephritis), 18 with membranous nephropathy (MN), 3 with focal segmental glomerulosclerosis (FSGS), and one with mesangioproliferative glomerulonephritis (MPGN), were treated by MMF combined with prednisone. The initial dosage of MMF was 1.0 - 2.0 g/d for three months and then the dosage was tapered gradually. The duration of MMF treatment was at least six months. Prednisone at the dose of 20 - 60 g/d was used at the beginning of the combined treatment and then the dosage was tapered gradually. Follow-up interview was conducted regularly. Four patients were rebiopsyed by the end of observation. RESULTS: The combined treatment of MMF/prednisone decreased the urine protein and elevated the serum albumin significantly among patients with minor lesion and MN (P < 0.001). All patients with minor lesion achieved clinical remission. Eleven of the nineteen cases responded within four weeks, and twelve of them obtained complete clinical remission. The dosage of prednisone could be tapered smoothly among the steroid dependent patients. Thirteen of the eighteen patients with MN achieved remission, however only six responded within four weeks and only three of them achieved complete clinical remission. During the treatment, four patients experienced transient increase of urine protein due to infection and recovered spontaneously without alteration of treatment. Side effects were tolerable except one case was withdrawn due to the decrease of hemoglobin. Renal function remained stable during the treatment. No obvious alteration could be found in renal biopsy by the end of treatment among four patients. CONCLUSION: MMF is an effective and safe immunosuppressive agent for refractory nephrotic syndrome.

Adolescent↗
PubMed2001

The sequence of the human genome.

A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.

Algorithms↗
PubMed2001

Sex pheromone components in oral secretions and crop of male Caribbean fruit flies, Anastrepha suspensa (Loew).

Chemical analysis of hexane extracts of the oral secretions from male Caribbean fruit flies, Anastrepha suspensa, resulted in identification of pheromone components including: anastrephin, epianastrephin, suspensolide, beta-bisabolene, and alpha-farnesene in a ratio of 63:396:4:8:1. Extracts of the crop from male flies contained these same components. No pheromone was detected in the extracts of female oral secretions. Bioassay of the oral secretions indicated that females were attracted to oral secretions from males but not from females. The amounts of anastrephin and epianastrephin in male oral secretions changed with age and time of the day, and were correlated with the amounts of volatile pheromone components released by male flies. The amounts of suspensolide, beta-bisabolene, and alpha-farnesene in the crop tissue were greater than those in the crop liquid, while amounts of anastrephin and epianastrephin in the crop tissue and crop liquid changed during the day. Generally, the amounts of suspensolide and beta-bisabolene decreased, and the amounts of anastrephin and epianastrephin increased from 9 am to 6 pm in both crop tissue and crop liquid. The amounts of anastrephin and epianastrephin from crop tissue or crop liquid incubated with suspensolide were significantly higher than those of control. The data show that oral secretions deposited on leaves by males contained terpenoid pheromone components that attract females and that suspensolide was converted to anastrephin and epianastrephin by enzymatic degradation in the crop of male flies.

Animals↗
PubMed2001

Elucidation of new structures in lignins of CAD- and COMT-deficient plants by NMR.

Studying lignin-biosynthetic-pathway mutants and transgenics provides insights into plant responses to perturbations of the lignification system, and enhances our understanding of normal lignification. When enzymes late in the pathway are downregulated, significant changes in the composition and structure of lignin may result. NMR spectroscopy provides powerful diagnostic tools for elucidating structures in the difficult lignin polymer, hinting at the chemical and biochemical changes that have occurred. COMT (caffeic acid O-methyl transferase) downregulation in poplar results in the incorporation of 5-hydroxyconiferyl alcohol into lignins via typical radical coupling reactions, but post-coupling quinone methide internal trapping reactions produce novel benzodioxane units in the lignin. CAD (cinnamyl alcohol dehydrogenase) downregulation results in the incorporation of the hydroxycinnamyl aldehyde monolignol precursors intimately into the polymer. Sinapyl aldehyde cross-couples 8-O-4 with both guaiacyl and syringyl units in the growing polymer, whereas coniferyl aldehyde cross-couples 8-O-4 only with syringyl units, reflecting simple chemical cross-coupling propensities. The incorporation of hydroxycinnamyl aldehyde and 5-hydroxyconiferyl alcohol monomers indicates that these monolignol intermediates are secreted to the cell wall for lignification. The recognition that novel units can incorporate into lignins portends significantly expanded opportunities for engineering the composition and consequent properties of lignin for improved utilization of valuable plant resources.

Alcohol Oxidoreductases↗
PubMed2001

Immunological methods for the study of Zoogloea strains in natural environments.

Since Zoogloea ramigera has been considered to be important in aerobic wastewater treatment, we have evaluated several methods for detecting and enumerating Z. ramigera in water and wastewater samples. Indirect immunoassay methods for the detection of Zoogloea strains were developed using polyclonal antibodies against the cells or the isolated exocellular polymer (EP) of the neotype Zoogloea ramigera strain 106 (ATCC 19544). The primary antibodies reacted with the cells and the exopolymer associated with finger-like zoogloeal projections, but not with other bacteria from natural samples. These antibodies allowed detection of Z. ramigera in environmental samples. Scanning electron microscopy (SEM) was used to show that the cells and the exocellular polymer of naturally occurring zoogloeal projections are antigenically and structurally related to those of Z. ramigera 106. Both immunological procedures and probes complementary to regions on the 16S rRNA could detect Z. ramigera in natural samples but the immunological procedures were easier to use. RT-PCR was also used to detect Z. ramigera in natural samples. These methods were also used to identify Z. ramigera in biofilms that developed over wastewater samples as part of an MPN procedure that was used to quantitate Z. ramigera at different stages of the wastewater treatment process and in different lakes. Z. ramigera could be found in all stages of wastewa ter treatment processes, from raw wastewater to chlorinated effluent, The highest concentration of Z. ramigera was found in the mixed liquor stage of the a wastewater treatment plant. Additionally, Z. ramigera was found in all eutrophic and mesotrophic lakes and in some oligotrophic lakes.

Biofilms↗
PubMed2001

NMR evidence for benzodioxane structures resulting from incorporation of 5-hydroxyconiferyl alcohol into Lignins of O-methyltransferase-deficient poplars.

Benzodioxane structures are produced in lignins of transgenic poplar plants deficient in COMT, anO-methyltransferase required to produce lignin syringyl units. They result from incorporation of 5-hydroxyconiferyl alcohol into the monomer supply and confirm that phenols other than the three traditional monolignols can be integrated into plant lignins.

Dioxanes↗
PubMed2001

Enzymes in pancreatic islets that use NADP(H) as a cofactor including evidence for a plasma membrane aldehyde reductase.

Recent evidence of a pyruvate malate shuttle capable of transporting a large amount of NADPH equivalents out of mitochondria in pancreatic islets suggests that cytosolic NADP(H) plays a role in beta cell metabolism. To obtain clues about these processes the activities of several NADPH-utilizing enzymes were estimated in pancreatic islets. Low levels of pyrroquinolone quinone (PQQ) and low levels of enzyme activity that reduce PQQ were found in islets. Low activities of palmitoyl-CoA and stearoyl-CoA desaturases were also detected. Significant activities of glutathione reductase, aldose reductase (EC.1.1.1.21) and aldehyde reductase (EC.1.1.1.2) were present in islets. Potent inhibitors of aldehyde and aldose reductases inhibited neither glucose-induced insulin release nor glucose metabolism in islets indicating that these reductases are not directly involved in glucose-induced insulin reaction. Over 90% of aldose reductase plus aldehyde reductase enzyme activity was present in the cytosol. Kinetic and chromatographic studies indicated that 60-70% of this activity in cytosol was due to aldehyde reductase and the remainder due to aldose reductase. Aldehyde reductase-like enzyme activity, as well as aldose reductase immunoreactivity, was detected in rat islet plasma membrane fractions purified by a polyethylene glycol-Dextran gradient or by a sucrose gradient. This is interesting in view of the fact that voltage-gated potassium channel beta subunits that contain aldehyde and aldose reductase-like NADPH-binding motifs have been detected in plasma membrane fractions of islets [Receptors and Channels 7: 237-243, 2000] and suggests that NADPH might have a yet unknown function in regulating activity of these potassium channels. Reductases may be present in cytosol to protect the insulin cell from molecules that cause oxidative injury.

Aldehyde Reductase↗
PubMed2001

[Methodological studies on the evaluation of family burden due to injuries].

OBJECTIVE: To evaluate the method for describing the burden and dimensions of injury on family. METHODS: Eighty-four families of patients with injury from the selected families were studied. Status on family function, including before and after the suffering disease, were measured with Family APGAR index. Present family function was re-measured one week after the initial study. The burden of injury on these families was measured with Family Burden Score. RESULTS: There were significant differences (P < 0.01) between scores of APGAR before and after the onset of injury. Forty-one point six seven percent of the families were with dysfunctions prior to the injuries, while 89.29% of families having dysfunctions for the time being. There were universal burden on the families of patients with injury in multi-dimensions, including economic status, routine life, entertainment, relationship between members, physiological and psychological health of the members, and social relationship of and within the families. CONCLUSION: Injury may bring impacts to the patient's family in multi-dimensions and induce dysfunction to patient's family. Both patients and their families should be involved when providing health care to and evaluating burden of injury on them.

Adult↗
PubMed2001

Dual function of human necrosis factor receptor 75 in cytotoxicity induced by human tumor necrosis factor alpha.

AIM: To study the function of human TNF receptor-75 (hTR75) and the interaction between human TNF receptor-55 (hTR55) and hTR75 in hTNFalpha-induced cytotoxicity. METHODS: HEp-2 cells were transfected with bicistronic expression vector of hTR75 gene, and HEp-2-A75 cells with intrinsic hTR55 and overexpressed hTR75 were obtained. Two hTNFalpha muteins with exclusive specificity for hTR55 or hTR75 were constructed, expressed in high-levels in E coli, and then purified. hTNFalpha-induced cytotoxicity was determined by crystal violet colorimetric method. RESULTS: The expression of hTR75 in HEp-2 cells was demonstrated by RT-PCR and indirect ELISA, and was quantified by binding of [125I]hTNFalpha and Scatchard analysis. The overexpressed hTR75 could markedly increase the susceptibility of HEp-2 cells to hTNFalpha. CONCLUSION: hTR75 could not only partially mediate hTNFalpha-induced cytotoxicity independently but also fulfill an accessory role in enhancing or synergizing hTR55-mediated cytotoxicity. It played a dual function in hTNFalpha-induced cytotoxicity in HEp-2 cells.

Antigens, CD↗
PubMed2001

A novel human tumor necrosis factor alpha mutant showed potent antitumor activity and reduced toxicity in vivo.

AIM: To study the antitumor activity and systemic toxicity of human tumor necrosis factor alpha (hTNFalpha) mutant M2 (R2K-N30S-R32W-L157F-hTNFalpha). METHODS: Mouse sarcoma S180 tumors and hepatoma HAC tumors were implanted into mice, and human urocyst carcinoma CP-3 tumors were implanted into nude mice. The xenografted mice were injected with wild-type hTNFalpha and its mutant M2 at different doses. After 7 d (mice) or 10 d (nude mice) of injection, the tumor weight was measured to calculate the inhibition rate of hTNFalpha and M2. Systemic toxicity experiments were done on Rhesus monkeys by injecting them with wild-type hTNFalpha and mutant M2 respectively for 10 consecutive d. Observations were made on the monkeys both before and after the injection. RESULTS: For mice implanted with sarcoma S180 and hepatoma HAC tumors, the inhibition rate of M2 was similar to that of wild-type hTNFalpha at the dose of 0.025 mg/kg, while for nude mice implanted with human urocyst carcinoma CP-3, the inhibition rate of M2 (45.5 %) was much higher than that of wild-type hTNFalpha (15.5 %). When the dose came to 0.25 and 2.5 mg/kg respectively, however, the inhibition rate of M2 greatly increased (the highest was 75.9 %). The tests of systemic toxicity of hTNFalpha and its mutant M2 in monkeys proved that M2 presented lower toxicity than wild-type hTNFalpha did. CONCLUSION: hTNFalpha mutant M2 not only presented higher antitumor activity than wild-type hTNFalpha did on mouse tumor (S180 and HAC)- and human tumor (CP-3)-implanted mice, but also showed lower systemic toxicity in the Rhesus monkey.

Animals↗
PubMed2001

Immunity induced by DNA vaccine of plasmid encoding the rhoptry protein 1 gene combined with the genetic adjuvant of pcIFN-gamma against Toxoplasma gondii in mice.

OBJECTIVE: To construct the eukáryotic expression recombinant plasmid, pcIFN-gamma, as a genetic adjuvant and observe the immune responses elicited by pcDNA3-rhoptry protein 1 (pc-ROP1) combined with pcIFN-gamma against Toxoplasma gondii (T. gondii) infection in mice. METHODS: A fragment of the IFN-gamma gene was directly inserted into the pcDNA3 plasmid and identified by two restriction endonucleases digestion. pcIFN and pcROP1 DNA was injected into the left leg muscle of mice at a dosage of 100 micrograms, and a booster vaccination was given at the same dosage after two weeks. Control groups were injected with pcDNA3 blank plasmid or normal saline. At 30, 50 and 70 days after booster injection, kinetic tests were carried out: MTT assay for the proliferation response of T lymphocyte cells and the activity of NK cells, sandwich ABC-ELISA for the determination of IFN-gamma, IL-2 and IL-10; a serum enzymetic aassay for nitric oxide (NO) in sera and ELISA for the titer of IgG antibody in sera. RESULTS: The recombinant plasmid, pcIFN-gamma was constructed. The proliferation response of spleen T lymph cells, NK cell killing activity, and serum levels of IFN-gamma, IL-2 and NO in mice injected with pcROP1 and pcIFN-gamma were higher than in those injected with pcROP1 alone. There was no difference in IgG antibody levels between the two groups. CONCLUSION: The genetic adjuvant, pcIFN-gamma, could enhance the cellular immune response induced by DNA vaccine of pcROP1 in mice against Toxoplasma gondii infection.

Animals↗
PubMed2001

Surgical treatment of 52 patients with congenital coronary artery fistulas.

OBJECTIVE: To evaluate the outcome of surgical treatment for congenital coronary artery fistulas (CAF) in 52 patients seen between May 1988 and July 1999. METHODS: Fifty-two patients ranging in age from 9 months 58 years (mean 15.7 +/- 16.4 years) were studied. Thirty-six patients had no other cardiac defects, 9 of those patients were more than 20 years old and presented with symptoms. Only one of 36 patients less than 20 years old had clinical findings before surgery. Sixteen patients had associated cardiac lesions. The site of fistula origin was the right coronary artery in 37 patients (71.2%), and the left coronary artery in 15 patients (28.8%). The sites of CAF drainage were the right ventricle, right atrium, left ventricle, left atrium and pulmonary artery in 22 (42.3%), 16 (30.8%), 6 (11.5%), 3 (5.8%), and 5 (9.6%) patients, respectively. The mean diameter of the fistula in 43 patients with single ostium was 7.34 +/- 4.12 mm. RESULTS: Cardiopulmonary bypass was used in all patients and no patient died. An arteriotomy was made on the anomalous coronary artery and the proximal opening of a fistula was closed within the vessel in 10 patients. Closure of the distal opening of a fistula draining into a cardiac chamber or pulmonary artery was performed in 26 patients. In 16 patients, both the proximal and distal opening were closed. Two and 3 distal opening of a fistula were found in 6 and 3 patients, respectively. No residual shunt was found before patients were discharged from the hospital. Forty patients were followed up for a mean period of 3.14 +/- 1.84 years. The remaining 12 patients could not be contacted during follow-up. No clinical symptoms were found in those patients during follow-up but one patient still presented with ST-T change. CONCLUSION: Early and properly surgical management is safe and effective for congenital coronary fistula.

Adolescent↗
PubMed2001

Construction of a recombinant plasmid harbouring the rhoptry protein 1 gene of Toxoplasma gondii and preliminary observations on DNA immunity.

OBJECTIVE: To observe the immune responses elicited in BALB/c mice by a DNA vaccine. A gene encoding rhoptry protein 1 (ROP1) from Toxoplasma gondii (T. gondii) was cloned into vector pcDNA3. METHODS: Amplifyied gene fragments coding for ROP1 from the genomic DNA of T. gondii ZS2 were inserted into cloning vector, pUC18, and sub-cloned into pcDNA3. Mice were injected at a dosage of 100 micrograms recombinant plasmid DNA by intramuscular injection and boosted after 2 weeks. pcDNA3 and normal saline were used as control. 30, 50 and 70 days after the second immunization, NK cell activity, T lymphocyte proliferation and sub-clusters and serum IgG antibody were assayed. RESULTS: The specific gene fragment coding for ROP1 was amplified and a pcROP1 recombinant was constructed. At 30 days after immunization, the spleens of the mice were obviously enlarged evidently. NKC activity and the proliferation of spleen T lymphocytes seen on MTT assay were higher in pcROP1 group than in the controls. The number of CD4+ T cells exhibited no obvious increase compared with that of the control, but CD8+ T cells were obviously increased (P < 0.05). At 90 days after vaccination, the titer of IgG antibody in the serum of vaccinated mice was positive (1:100). CONCLUSION: pcROP1 was constructed and it could elicit both cellular and humoral immune responses in immunized mice.

Animals↗
PubMed2001

[The effects of perfluorodecalin on the anterior chamber angle and intraocular pressure in rabbits].

OBJECTIVE: To observe the effects of purfluorodecalin on the anterior chamber (AC) angle and intraocular pressure (IOP) in rabbits. METHODS: 0.05 ml perfluorodecalin was injected into right AC of 17 white rabbits and the same does of balanced salt solusion(BSS) was given to the controll group (6 rabbits). The IOP was measured before and 1, 2, 3, 4, 8, 12, 16 weeks after the injection. The treatment rabbits were sacrificed on the week of 1, 2, 4, 8 and 16 postoperatively. The eyes were enucleated and the histological examination was performed. RESULTS: There's no statistic IOP difference in the controll group before and after the injection of BSS. In treatment group, the IOP is similar to the preoperation level (11.62 +/- 6.35 mmHg) on the 7th postoperative day (10.82 +/- 3.17 mmHg, P < 0.05). A increment of IOP was measured at the week of 2 to 4, 8, 12, and 16 postoperatively (P < 0.01). Perfluorodecalin, having a 'fish eggs' or bubbles appearance, was noted in the inferior AC. Histopathologically, transparent single or fused vesicles and macrophages were accumulated at the AC angler in treatment rabbits. Some lymphocytes and neutrophils were aslo noted here. Trabeculae degenerated and intertrabecular space increased. CONCLUSIONS: The anterior chamber injection of perfluorodeclin could lead to a longstanding increase of IOP. Inflammatory reaction and trabeculae degeneration were seen in the anterior chamber angler.

Animals↗