Biomedical subjects

C Lu

Publications and source records attributed to C Lu.

At least 55 records · Page 3Linked to original sources

PubMed2001

An amplified fragment length polymorphism map of the silkworm.

The silkworm (Bombyx mori L.) is a lepidopteran insect with a long history of significant agricultural value. We have constructed the first amplified fragment length polymorphism (AFLP) genetic linkage map of the silkworm B. mori at a LOD score of 2.5. The mapping AFLP markers were genotyped in 47 progeny from a backcross population of the cross no. 782 x od100. A total of 1248 (60.7%) polymorphic AFLP markers were detected with 35 PstI/TaqI primer combinations. Each of the primer combinations generated an average of 35.7 polymorphic AFLP markers. A total of 545 (44%) polymorphic markers are consistent with the expected segregation ratio of 1:1 at the significance level of P = 0.05. Of the 545 polymorphic markers, 356 were assigned to 30 linkage groups. The number of markers on linkage groups ranged from 4 to 36. There were 21 major linkage groups with 7-36 markers and 9 relatively small linkage groups with 4-6 markers. The 30 linkage groups varied in length from 37.4 to 691.0 cM. The total length of this AFLP linkage map was 6512 cM. Genetic distances between two neighboring markers on the same linkage group ranged from 0.2 to 47 cM with an average of 18.2 cM. The sex-linked gene od was located between the markers P1T3B40 and P3T3B27 at the end of group 3, indicating that AFLP linkage group 3 was the Z (sex) chromosome. This work provides an essential basic map for constructing a denser linkage map and for mapping genes underlying agronomically important traits in the silkworm B. mori L.

Animals↗

PubMed2001

Characterization of photosynthetic pigment composition, photosystem II photochemistry and thermal energy dissipation during leaf senescence of wheat plants grown in the field.

Photosynthetic pigment composition and photosystem II (PSII) photochemistry were characterized during the flag leaf senescence of wheat plants grown in the field. During leaf senescence, neoxanthin and beta-carotene decreased concomitantly with chlorophyll, whereas lutein and xanthophyll cycle pigments were less affected, leading to increases in lutein/chlorophyll and xanthophyll cycle pigments/chlorophyll ratios. The chlorophyll a/b ratio also increased. With the progression of senescence, the maximal efficiency of PSII photochemistry decreased only slightly in the early morning (low light conditions), but substantially at midday (high light conditions). Actual PSII efficiency, photochemical quenching and the efficiency of excitation capture by open PSII centres decreased significantly both early in the morning and at midday and such decreases were much greater at midday than in the early morning. At the same time, non-photochemical quenching, zeaxanthin and antheraxanthin contents at the expense of violaxanthin increased both early in the morning and at midday, with a greater increase at midday. The results in the present study suggest that a down-regulation of PSII occurred in senescent leaves and that the xanthophyll cycle plays a role in the protection of PSII from photoinhibitory damage in senescent leaves by dissipating excess excitation energy, particularly when exposed to high light.

Cellular Senescence↗

PubMed2001

Developmental abnormalities and reduced fruit softening in tomato plants expressing an antisense Rab11 GTPase gene.

A cDNA clone from tomato fruit encodes a protein with strong homology with the rab11/YPT3 class of small GTPases that is thought to be involved in the control of protein trafficking within cells. The gene, LeRab11a, showed a pattern consistent with a single copy in DNA gel blots. The corresponding mRNA was developmentally regulated during fruit ripening, and its expression was inhibited in several ripening mutants. Its reduced expression in the Never-ripe mutant indicates that it may be induced by ethylene in fruit. The ripening-induced expression in tissues that are undergoing cell wall loosening immediately suggests a possible role in trafficking of cell wall-modifying enzymes. The message also was produced in leaves and flowers but not in roots. Antisense transformation was used to generate a "mutant phenotype." Antisense fruit changed color as expected but failed to soften normally. This was accompanied by reduced levels of two cell wall hydrolases, pectinesterase and polygalacturonase. There were other phenotypic effects in the plants, including determinate growth, reduced apical dominance, branched inflorescences, abnormal floral structure, and ectopic shoots on the leaves. In some plants, ethylene production was reduced. These data suggest an alternative or additional role in exocytosis or endocytosis of homeotic proteins, hormone carriers, or receptors.

Base Sequence↗

PubMed2001

LFA-1 expression on target cells promotes human immunodeficiency virus type 1 infection and transmission.

While CD4 and the chemokine receptors are the principal receptors for human immunodeficiency virus (HIV), other cellular proteins, such as LFA-1, are also involved in HIV infection. LFA-1 and its ligands, ICAM-1, ICAM-2, and ICAM-3, can be expressed on the cells infected by HIV, as well as on the HIV virions themselves. To examine the role of LFA-1 expressed on target cells in HIV infection, Jurkat-derived Jbeta2.7 T-cell lines that express either wild-type LFA-1, a constitutively active mutant LFA-1, or no LFA-1 were used. The presence of wild-type LFA-1 enhanced the initial processes of HIV infection, as well as the subsequent replication and transmission from cell to cell. In contrast, the constitutively active LFA-1 mutant failed to promote virus replication and spread, even though this mutant could help HIV enter cells and establish the initial infection. This study clearly demonstrates the contribution of LFA-1 in the different stages of HIV infection. Moreover, not only is LFA-1 expression important for initial HIV-cell interaction, subsequent replication, and transmission, but its activity must also be properly regulated.

Cell Adhesion↗

PubMed2001

Mechanism of temporal gradients in shear-induced ERK1/2 activation and proliferation in endothelial cells.

The aim of the current study was to investigate the intracellular signaling cascade that leads to temporal gradients in shear (TGS)-induced endothelial cell proliferation, with a focus on the involvement of extracellular signal-regulated kinases 1 and 2 (ERK1/2). With the use of well-defined pulsatile, impulse, step, and ramp laminar flow profiles, we found that TGS (impulse flow and pulsatile flow) induced an enhanced and sustained (>30 min) phosphorylation of ERK1/2 relative to step flow (which contains a step increase in shear followed by steady shear), whereas steady shear (ramp flow) alone downregulated activated ERK1/2. Nitric oxide (NO) was found to mediate both the stimulatory effect of TGS and the inhibitory effect of steady shear on endothelial ERK1/2 phosphorylation. Reactive oxygen species (ROS) were also demonstrated to be associated with TGS-induced ERK1/2 phosphorylation. Both G(q/11) and G(i3) were necessary for the activation of ERK1/2 by TGS. Finally, the TGS-induced endothelial proliferative response was abolished by ERK1/2 inhibition. Our study demonstrated the essential role of G proteins, NO, and ROS in TGS-dependent ERK1/2 activation and proliferative response in vascular endothelial cells.

Cell Division↗

PubMed2001

High throughput studies of gene expression using green fluorescent protein-oxidative stress promoter probe constructs: the potential for living chips.

Green fluorescent protein fusions were constructed with several oxidative stress promoters from Escherichia coli. These promoters were chosen for their induction by reactive oxygen species (ROS) such as superoxide, hydrogen peroxide, and hydroxyl radicals. When exposed to various free radical insults, the cells fluoresced with great specificity based on the corresponding ROS. In this work, we propose a way in which these constructs could be used to study the mode of action of a variety of antitumor drugs. This approach offers the possibility of complementing gene chip technology by the creation of living chips for high throughput screening as well as studying differential gene expression.

Antineoplastic Agents↗

PubMed2001

Grtp1, a novel gene regulated by growth hormone.

An in vitro model of GH-responsive cells was subjected to microarray analysis to identify a novel gene regulated by GH. This 258 amino acid protein, we term GH Regulated TBC Protein-1 (GRTP1), contains the TBC signature motif of GTPase activator proteins of Rab-like small GTPases. Northern blot analysis revealed a 1.3 kb major mRNA species, most abundant in testes. TaqMan assay confirmed that in the mouse, Grtp1 is expressed at highest levels in testes, with lesser abundance in intestine, kidney, lung, and liver. In the testis, expression of Grtp1 significantly increases post-pubertally. Administration of GH to mice increased levels of GRTP1 mRNA in testes (140%), but decreased GRTP1 mRNA abundance in kidney (50%) and liver (25%). Grtp1 was localized to mouse proximal chromosome 8. Orthologs of this protein are present in human, mouse, rat, and drosophila suggesting that GRTP1 has an important biological role(s).

Amino Acid Sequence↗

PubMed2001

Biological monitoring survey of organophosphorus pesticide exposure among pre-school children in the Seattle metropolitan area.

In this study we assessed organophosphorus (OP) pesticide exposure among children living in two Seattle metropolitan area communities by measuring urinary metabolites, and identified possible exposure risk factors through a parental interview. We recruited children in clinic and outpatient waiting rooms. We obtained spot urine samples in the spring and fall of 1998 from 110 children ages 2-5 years, from 96 households. We analyzed urine samples for six dialkylphosphate (DAP) compounds, the common metabolites of the OP pesticides. Through parental interviews we gathered demographic and residential pesticide use data. At least one of the DAP metabolites was measured in 99% of the children, and the two predominant metabolites (DMTP and DETP) were measured in 70-75% of the children. We found no significant differences in DAP concentrations related to season, community, sex, age, family income, or housing type. Median concentrations of dimethyl and diethyl DAPs were 0.11 and 0.04 micromol/L, respectively (all children). Concentrations were significantly higher in children whose parents reported pesticide use in the garden (0.19 vs. 0.09 micromol/L for dimethyl metabolites, p = 0.05; 0.04 vs. 0.03 micromol/L for diethyl metabolites, p = 0.02), but were not different based on reported pet treatment or indoor residential use. Nearly all children in this study had measurable levels of OP pesticide metabolites. Some of this exposure was likely due to diet. Garden pesticide use was associated with elevated metabolite levels. It is unlikely that these exposure levels would cause acute intoxication, but the long-term health effects of such exposures are unknown. We recommend that OP pesticide use be avoided in areas where children are likely to play.

Child, Preschool↗

PubMed2001

Effects of organic solvents on the activities of cytochrome P450 isoforms, UDP-dependent glucuronyl transferase, and phenol sulfotransferase in human hepatocytes.

We studied the effects of acetonitrile, dimethyl sulfoxide (DMSO), and methanol (MeOH) in human hepatocytes on cytochrome P450 (CYP) and phase II conjugation activities: phenacetin O-deethylation (CYP1A2), coumarin 7-hydroxylation (CYP2A6), tolbutamide 4-hydroxylation (CYP2C9), S-mephenytoin 4'-hydroxylation (CYP2C19), dextromethorphan O-demethylation (CYP2D6), chlorzoxazone 6-hydroxylation (CYP2E1), testosterone 6beta-hydroxylation (CYP3A4), and umbelliferone glucuronidation and sulfation. The solvents were evaluated at concentrations (v/v) of 0.1, 1, and 2%. Previously cryopreserved human hepatocytes pooled from multiple donors were used as suspension cultures in this study. DMSO was found to inhibit CYP2C9 and CYP2C19, CYP2E1, and CYP3A4 in a concentration-dependent manner. At 2% DMSO, the activities for the four isoforms were approximately 40% (CYP2C9), 23% (CYP2C19), and 11% (CYP2E1) of that observed for 0.1% acetonitrile and 45% (CYP3A4) of that observed for 1% acetonitrile. No apparent inhibitory effects were observed for the other activities evaluated. Methanol was found to inhibit CYP2C9 and CYP2E1 activities, but to a lesser extent than DMSO. Acetonitrile had no apparent effects on any of the on any of the activities evaluated. These findings should be considered when choosing an organic solvent for metabolism studies with human hepatocytes.

Acetonitriles↗

PubMed2001

[Study on the mode of inheritance for familial polycystic ovary syndrome].

OBJECTIVE: To investigate the mode of inheritance of polycystic ovary syndrome(PCOS). METHODS: The first female relatives with irregular cycle and the first male relatives with premature balding in each nuclear family were designated the affected. Their prevalence rates in families were respectively calculated. Analyses of segregation ratio were carried out among 139 nuclear families with PCOS by the methods of simple segregation and complex segregation of genetic epidemiology, respectively. RESULTS: The prevalence rates of irregular cycle among mothers and sisters with PCOS were 37.4% and 33.1% respectively, and the prevalence rates of premature balding among fathers and brothers of patients were 19.4% and 6.5%, respectively. The simple segregation analysis indicated that the segregation ratio of PCOS trait in siblings was 0.3023, the complex segregation analysis indicated that it fitted in with the inheritance model of co-dominant disorder with full penetrance and sporadic cases. The frequency of homozygote of disease gene in population was 0.046. CONCLUSION: PCOS presents the mode of co-dominant inheritance with complete penetrance.

Female↗

PubMed2001

[Preparation and identification of activity of antiplatelet-derived growth factor receptor beta subunit hammerhead ribozyme in vitro].

OBJECTIVE: To study the preparation and cleavage activity of ribozyme directed against platelet-derived growth factor (PDGF) receptor beta subunit gene transcript in vitro. METHODS: PDGF receptor B subunit gene fragments were cloned into T-vector under the control of T7 promotor. 32P-labeled PDGF receptor beta subunit transcripts as target-RNAs were transcribed in vitro and purified by PAGE. Ribozyme gene designed by computer targeting the extracellular domain was cloned into vector P1.5 between 5'-cis ribozyme and 3'-cis ribozyme. 32P-labeled ribozyme transcripts was gel-purified, incubated with target-RNAs at different conditions and autoradiographed after denaturing gel-electrophoresis. RESULTS: The preparation of ribozyme was correct. It was active at 37 degrees C. The optimal temperature was 50 degrees C, Km=13,20 nm, Kcat=0.28 min-1. The cleavage efficiency was up to 78.3%. CONCLUSIONS: Ribozyme prepared in vitro possesses specific catalytic activity.

Animals↗

PubMed2001

Beneficial effects of diltiazem during myocardial reperfusion: a randomized trial in acute myocardial infarction.

BACKGROUND: Although in experimental models of coronary occlusion diltiazem administration has been shown to reduce the degree of stunning and of reperfusion injury, the majority of clinical trials has failed to demonstrate significant benefits. The aim of this study was to evaluate the effect of diltiazem, administered before coronary reperfusion, on infarct size, residual myocardial viability and recovery of left ventricular function. METHODS: We studied 90 patients admitted within 3 hours of the onset of symptoms of acute myocardial infarction. They were immediately randomized to either intravenous diltiazem (10 mg bolus + 10 mg/hour for 3 days) (group 1, n = 43) or placebo (group 2, n = 47) and subsequently treated with recombinant tissue-type plasminogen activator. All underwent serial echocardiograms upon admission, 4 days post-admission during low-dose dobutamine stress echo, at discharge and after 6 months. We calculated the dysfunction score (1 = hypokinesia, 2 = akinesia, 3 = dyskinesia) on admission and its percent reduction after dobutamine (viability) and at follow-up (recovery). The 12-lead electrocardiograms were continuously monitored for 3 days and coronary angioplasty was performed whenever the residual stenosis was > 60%. RESULTS: Upon admission, there were no differences in age, sex, infarct location and size, degree of ST-segment elevation, time from onset of symptoms and dysfunction score. Creatine kinase peaked early in 70% of patients in both groups; the incidences of recurrent ischemia, infarct-related vessel patency and the need for coronary angioplasty were also similar. The creatine kinase peak was significantly higher in group 2 (2931 +/- 2456 vs 1726 +/- 1004 IU/l, p < 0.05). Conversely, in group 1 the residual viability was significantly higher (51 +/- 23 vs 36 +/- 30% improvement in dysfunction score, p < 0.05) and the early recovery of regional function was significantly greater (35 +/- 34 vs 18 +/- 22% at discharge, p < 0.05). On the other hand, the delayed recovery was not significantly different (15 +/- 29 vs 21 +/- 32% from the time of discharge to 6 months of follow-up). CONCLUSIONS: Intravenous diltiazem, started before coronary reperfusion, has beneficial effects on the infarct size, residual viability and recovery of regional function. If confirmed by larger trials, these preliminary results suggest the use of diltiazem as adjunctive therapy in patients with acute myocardial infarction and undergoing reperfusion.

Adult↗

PubMed2001

[Preliminary study on application of blastocyst culture and day 5 transfer in patients with low oocyte number].

OBJECTIVE: To evaluate whether blastocyst culture and transfer in patients with low oocyte number can effectively improve the outcome of in vitro fertilization-embryo transfer treatment. METHODS: Retrospectively analyze 59 couples received conventional in vitro fertilization and embryo transfer (IVF-ET) treatment in our center from January to February 2000. Twenty-one couples had blastocyst culture and day 5 embryo transfer and another 38 couples had day 2 embryo transfer as the control. Their clinical and laboratory results were compared between these two groups. RESULTS: In day 5 group the mean oocytes retrieved were (6.6 +/- 2.8), the clinical pregnancy rates (PRs) was 43% and the life delivery rate was 38%; while in day 2 group the results were (6.9 +/- 3.7), 37% and 29% respectively. There was no significant difference between two groups. No high-order multiple birth occurred in day 5 group, but in day 2 group there were two cases: one with triplets and another with pentadriplet who had the embryos reduction. CONCLUSIONS: These results demonstrate that nonselective blastocyst culture and transfer in patients with low oocyte number seems not effectively to improve the PRs and the delivery rate, but may decrease the occurrence of multiple birth without affecting the final pregnancy results when compared with conventional day 2 transfer.

Blastocyst↗

PubMed2001

Determination of the dominant language hemisphere by functional MRI in patients with temporal lobe epilepsy.

OBJECTIVE: To determine the dominant language hemisphere in patients with intractable temporal lobe epilepsy before surgical treatment by using functional MRI (fMRI). METHODS: Twelve patients underwent fMRI. Among them, 4 patients also underwent the Wada test. Anterior temporal lobectomy was performed on patients with epileptic focus on the non-dominant hemisphere, and selective amygdalo-hippocampectomy on patients with epileptic focus on the dominant hemisphere. RESULTS: Ten patients had left dominance, and 2 right dominance. The fMRI results were concordant with Wada test results in the 4 patients who accepted the Wada test. Seven patients underwent anterior temporal lobectomy, and 5 underwent selective amygdalo-hippocampectomy. There was no post-operative dysphasia. CONCLUSION: fMRI is an alternative method of noninvasive functional mapping for language dominance in patients with temporal lobe epilepsy.

Adult↗

PubMed2001

Gene expression of glucose transporters and its regulation by glucose in mesothelial cells.

OBJECTIVE: To observe the influence of glucose on the expression of glucose transporters (GluTs) in peritoneal tissues. METHODS: Mesothelial cells (MsCs) from Sprague-Dawley (SD) rats were cultured in medium with glucose 214.4 mmol/L or 75.5 mmol/L. The normal medium with glucose 17.5 mmol/L was used as control. Total RNA was extracted from each sample after 24 hours incubation. Reverse transcript polymerase chain reaction (RT-PCR) was performed with primers corresponding to sodium-glucose transporter (SGIT1) and GluT1-GluT4. mRNA expression of the above GluTs from each sample was measured with quantitative PCR. RESULTS: GluT1 and GluT2 mRNA can be detected in MsCs from SD rats, while no positive bands can be found specifically for GluT3, GluT4 and SGiT1. Quantitating the amount of PCR products indicated that the levels of GluT1 mRNA in MsCs cultured 24 h in both 214.4 mmol/L glucose and 75.5 mmol/L glucose medium decreased dramatically compared with that in normal medium (P < or = 0.01). While under the same conditions, the levels of GluT2 mRNA in MsCs cultured 24 h in 214.4 mmol/L and 75.5 mmol/L glucose medium both increased significantly (P < 0.01). CONCLUSIONS: GluT1 is strongly expressed in MsCs under normal glucose levels and decreased dramatically under high glucose conditions, while GluT2 expressed at a low level in normal medium and increased greatly after incubation in high glucose conditions. This may play a great role in glucose absorption during peritoneal dialysis and have some connection with ultrafiltration failure due to the alteration of glucose absorption after long-term dialysis.

Animals↗

PubMed2001

[Studies on the ribosomal RNA gene(rDNA) of a microsporidium isolated from Pieris rapae L].

Nuclotide sequence (1205 bp) of small subunit ribosomal RNA (SSUrDNA) of a microsporidium isolated from Pieris rapae L. (abbr:MPr) was specifically amplified by polymerase chain reaction (PCR). Another fragment of 657 bp downstream of MPr SSUrDNA 3'end was amplified with two other primers. Within this 657 bp fragment, the putative 3'terminus of MPr SSUrDNA and the extreme 5' of large subunit ribosomal RNA gene. (LSUrDNA) were identified, which situated at base 145, 146-186 and 187, respectively. Then the full sequence of MPr ssurDNA is 1245 bp. Its GC content was also nearly 34%. The ITS region (internal transcribed spacer), positioned between the ssu and LSUrRNA genes, was found to be 41 bp in length. The LSUrDNA 580r region of MPr is 470 bp, longer than 437 bp of Nosema apis, 447 bp of Nosema algerae. The secondary structure of MPr SSUrRNA was constructed. These analyses of MPr rRNA gene contributed to the somewhat limited microsporidian taxonomic classification based on morphology.

Animals↗

PubMed2001

[Analys of outer membrane protein and drug-resistant of Edwardsiella tarda].

The SDS-PAGE profiles of out membrane protein(OMP) of 27 Et strains showed diverse patterns and they could be divided into six types. Between 21 pathogenic strains and 6 non-pathogenic strains there were obviously difference. The pathogenic strains isolated from China belong to E type and were simary to ATCC 15947. The OMP bands of pathogenic strains were more and denser than those of the non-pathogenic strains, and the strains from same souce had the identical patters. Interestingly, the non-pathogenic strains from different sources also had the almost same OMP profiles. What's more, they were also high resistant to some antibiotics such as Smx, Gem Tet and so on, while the 18 pathogenic strains were sensitivity to these.

Anti-Bacterial Agents↗

PubMed2001

[Detection of pathogenic Edwarsiella tarda].

25 Edwardsiella tarda(Et) strains had been detected both on their viruslent factor Excellular Product (ECP), including the hemolysin and extracellular protease (ECPase), and on their pathogenicity to mice and Xiphophorus helleri. ECP was detected by Dot-ELISA with rabbit antiserum against ECP of reference strain JEL4. The results showed that the animal pathogenicity of Et had good correlation with its hemolysin other than with ECPase. The agreement between Dot-ELISA of JEL4 ECP and pathogenicity to animal was up to 100%. It was desirable to establish a detecting method, which only need detect the ECP with plate assay (PA) and Dot-ELISA, but needn't have animal experiment. Furthermore it is possible to develop a diagnosis kit of application to simplify the detecting procedure of pathogenic Et.

Animals↗