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Biomedical subjects

J Lu

Publications and source records attributed to J Lu.

At least 145 records · Page 8Linked to original sources
PubMed2001

Solution structure of cytochrome b(5) mutant (E44/48/56A/D60A) and its interaction with cytochrome c.

Using 1617 meaningful NOEs with 188 pseudocontact shifts, a family of 35 conformers of oxidized bovine microsomal cytochrome b5 mutant (E44/48/56A/D60A) has been obtained and is characterized by good resolution (rmsd to the mean structure are 0.047 +/- 0.007 nm and 0.095 +/- 0.008 nm for backbone and heavy atoms, respectively). The solution structure of the mutant, when compared with the X-ray structure of wild-type cytochrome b(5), has no significant changes in the whole folding and secondary structure. The binding between cytochrome b(5) and cytochrome c shows that the association constant of the mutant-cytochrome c complex is much lower than the one for wild-type complex (2.2 x 10(4) M(-1) vs. 5.1 x 10(3) M(-1)). The result suggests the four acidic residues have substantial effects on the formation of the complex between cytochrome b(5) and cytochrome c, and therefore it is concluded reasonably that the electrostatic interaction plays an important role in maintaining the stability and specificity of the complex formed. The competition between the ferricytochrome b(5) mutant and [Cr(oxalate)(3)](3-) for ferricytochrome c shows that site III of cytochrome c, which is a strong binding site to wild-type cytochrome b(5), still binds to the mutant with relatively weaker strength. Our results indicate that certain bonding geometries do occur in the interaction between the present mutant and cytochrome c and these geometries, which should be quite different from the ones of the Salemme and Northrup models.

Amino Acid Sequence↗
PubMed2001

Expression of DT-diaphorase and cytochrome P450 reductase correlates with mitomycin C activity in human bladder tumors.

Mitomycin C (MMC) is activated by DT-diaphorase (DTD) and cytochrome P450 reductase (P450R). In cancer cell lines, MMC cytotoxicity is correlated with DTD and P450R expression levels. The present study investigated the relationship between enzyme expression/activity and MMC cytotoxicity in patient bladder tumors. DTD and P450R expression was detected by competitive reverse transcription-PCR and their activity was measured by bioreductive assays. The expression of DTD and P450R in patient tumors (n = 29), as ratios to beta-actin levels, varied from 0 to 90% and 0 to 29%, respectively. The DTD expression was significantly correlated with P450R expression (r(2), 0.32; P < 0.01), whereas the average DTD level was 2-fold higher than that of P450R (P < 0.01). Among the 29 tumors, 21 provided sufficient materials to evaluate tumor sensitivity to MMC. The concentration of MMC required to produce 50% inhibition (IC(50)) of DNA precursor incorporation for a 2-h treatment ranged from 0.17 to 18.1 microg/ml, indicating a 110-fold intertumor variation, with the high-grade and more invasive tumors being less chemosensitive compared with the low-grade and less invasive tumors. Tumor sensitivity to MMC, as indicated by the inverse of IC(50) values, was positively correlated with the expression of DTD (r(2), 0.28; P < 0.05) and P450R (r(2), 0.26; P < 0.05). Multivariate analysis indicates DTD expression and P450R expression as better determinants of MMC activity compared with other pathobiological factors (e.g., tumor grade, stage, and labeling index) that have been shown to significantly correlate with MMC activity. Eleven tumors were studied for the relationship between gene expression level and enzyme activity of DTD and P450R. The DTD activity was significantly correlated with the gene expression level (r(2), 0.84; P < 0.001). For P450R, there is a trend of a correlation between enzyme activity and its mRNA level, but the correlation was not statistically significant (r(2), 0.28; P = 0.09). These data indicate that the sensitivity of patient bladder tumors to MMC is correlated with the expression of DTD and P450R in tumors and suggest that the lower expression of these enzymes in the high-grade and more invasive tumors is a cause of the lower efficacy of intravesical MMC in these tumors.

Adult↗
PubMed2001

[Detection of anti-HAV IgM and anti-HEV IgM in patients with sporadic acute hepatitis in Beijing between 1995-2000].

OBJECTIVE: To investigate the age ranges, liver function lesion and outcomes of sporadic acute hepatitis A and E in Beijing. METHODS: Enzyme immunoassay(EIA) was used for detection of anti-HAV and anti-HEV immunoglobulin M(IgM). Samples were collected from the patients with sporadic acute viral hepatitis in Beijing between 1995-2000. RESULTS: The total rate of positive for anti-HAV and anti-HEV was 55.2% (112) in 203 patients with acute hepatitis, 22.2% (45) and 33% (67) were positive separately for anti-HAV and anti-HEV in 112 patients. The duration of anti-HEV IgM was 45-60 days and that of anti-HAV IgM was at least 2-3 months. The patients with acute hepatitis A and hepatitis E all experienced jaundice, a rising of liver enzyme, but not developed to chronic hepatitis or to death. CONCLUSION: Acute hepatitis A as well as acute hepatitis E takes an important place in sporadic enterically transmitted hepatitis in Beijing.

Acute Disease↗
PubMed2001

[Apoptosis in pressure overload-induced heart hypertrophy].

Pressure overload can result in heart hypertrophy, and induce apoptosis, but the phenomenon of apoptosis during the forepart of cardiomyocyte hypertrophy remains unclear. The aim of this study was to inquire into the process of cardiomyocyte apoptosis during the forepart of cardiomyocyte hypertrophy. We constructed the hypertrophy model by transverse aortic constriction of male SD rat. The apoptosis ratio was detected by TUNEL method and FCM. The result demonstrated that hypertrophy indexes increased with the time of constriction, reached the highest level at day 7, maintained that level, and then decreased at day 91. The apoptosis ratio of cardiomyocyte at day 4 was higher than that at day 0 detected by FCM method, and the ratio at day 7 was markedly lower than that at day 4. After day 28, the apoptosis ratio of cardiomyocyte went up again with the time of constriction after surgery. TUNEL method revealed that positive nuclei were observed in cardiomyocytes exclusively in the left ventricle; the apoptosis ratio increased when constriction continued. TUNEL method confirmed the result of FCM. These data indicate that cardiac hypertrophy is initiated by apoptosis of cardiomyocyte, these two factors(hypertrophy and apoptosis) maintain the balance between growth and death during the early short period of aortic constriction, and when aortic constriction goes on they are involved in the pathogenesis of heart remodeling.

Adaptation, Physiological↗
PubMed2001

[Construction and expression in eukaryotic cells of HBsAg and B].

OBJECTIVE: To investigate the enhanced role of B(7-1) in gene immunization of eukaryotic vector expressing HBsAg, and further to eliminate the immunotolerance to hepatitis B virus. METHODS: B(7-1) and IRES-HBs with linker and promoter sequence prior to HBs gene were amplified with high fidelity PCR, then subcloned into plasmid pBluescriptks+, which was used to sequence. The eukaryotic expressing vector was constructed by inserting B(7-1) and IRES-HBs into plxsn. Recombinant vector was transfected into PA317 by means of lipid mixtures. Titre of pseudovirus packaged in PA317 cells was detected by infecting NIH3T3 cells. B(7-1) and HBsAg expression in PA317, NIH3T3, HepG(2), 293, EL4 cell lines was detected by RT-PCR, immunohistochemistry and ELISA, respectively. RESULTS: No change was found in the sequences of target genes amplified by high fidelity PCR compared with the known sequences. Plxsn-B(7-1)-HBs was constructed by first inserting B(7-1) into plxsn with enzyme EcoRI/XhoI, then IRES-HBs was inserted in the same way with enzyme XhoI/BamHI. 43 and 90 G418-resistant clones were obtained two weeks later after 1:10 and 1:5 passages at 24 hours after transfection. Titre of the peudovirus was 5.4x10(5) CFU/ml. B(7-1) was expressed in all the cell lines above by RT-PCR test. The contents of HBsAg in the supernatant of the PA317, NIH3T3, HepG(2), and 293 cells at 24, 48, 72 hours intervals were 0.15, 0.11, 0.20, 0.13; 0.63, 0.47, 0.76, 0.58; 0.77, 0.61, 0.89, 0.69, respectively. CONCLUSIONS: The retroviral vector expressing B(7-1) and HBsAg simultaneously is constructed successfully. The target antigens are expressed in above cell lines in vitro after transfection with lipids mixtures. It may be used to conduct gene immunization and to investigate the role of B(7-1) on HBsAg immune response, which may be further used to the prevention and therapy of hepatitis B.

Animals↗
PubMed2001

[Water quality of closed polyculture of penaeid shrimp with tilapia and constricted tagelus].

A variety of water quality parameters were monitored in enclosures for the polyculture of penaeid shrimp with tilapia and constricted tagelus. The result showed that the environment of the polyculture systems was better than that of monoculture one. The fluctuation of DO in the water of polyculture enclosures was less violent, and their lowest values were obviously higher than those in monoculture ones. The value of COD and the number of bacteria in the water of polyculture enclosures were significantly lower than those in monoculture ones(t-test, alpha < 0.05), showing that the amount of organic matter in the water of polyculture systems was less than that in monoculture one. The biomass of plankton and the concentration of chlorophyll-a in the polyculture enclosures were also lower, showing that the suppression of the filtering animals to the plankton was obvious. The accumulation of N and P in the sediment of polyculture enclosures was 39.76% and 51.26%, lower than those of monoculture ones, respectively; and the number of bacteria in the sediment was 7.63% lower. Therefore, it is obvious that closed culture system can greatly decrease the effluent to the coastal waters caused by the pond culture industry, and decrease the pollution to the coastal waters.

Animals↗
PubMed2001

[Assessment of ecosystem health--concept framework and indicator selection].

Based on the concept framework of ecosystem health, this paper discussed the suitable indicators to synthetically assess the ecosystem health in governed landscape. Healthy ecosystem means not only ecological health itself, but also the long-term maintenance of healthy human population and the beneficial promotion of social and economic development. Resilience, biodiversity and productivity are the characteristics of healthy ecosystem. The first step in the structure of indicators to assess ecosystem health should be the determination of precise indicator principles. According to the purpose of assessment and the principles of selecting indicator, the indicator system for assessing ecosystem health can be divided into three categories, namely, biophysical indicators, ecological indicators, and social and economic indicators.

Air↗
PubMed2001

[The polymorphism of (CAG)n repeats within androgen receptor gene among Chinese male population].

OBJECTIVE: To investigate the polymorphism of (CAG)n repeats within androgen receptor (AR) gene among normal Chinese male population. METHODS: dsDNA cycle sequencing and[alpha-(32)PdCTP] incorporated asymmol/Letric PCR-denaturing polyacrylamide gel electrophoresis(PAGE) were used to determine the number of (CAG)n repeats in normal men (n=107). RESULTS: The number of polymorphic (CAG)n repeats ranges from 11 to 29; the most frequent repeat is 22(20/107); the less frequent repeats are 23(15/107), 24(11/107), 21(11/107) and 20(8/107). CONCLUSION: The AR gene (CAG)n exhibits polymorphism among normal male population and the present work could serve as a basis for further exploration of its pathological and genetic significance.

Adolescent↗
PubMed2001

[Dyslipidaemia and insulin resistance in Chinese in Shanghai].

OBJECTIVE: To investigate the impact of dyslipidaemia on insulin resistance in Chinese individuals in Shanghai. METHODS: 830 individuals aged over 40 years (male 300, female 530) were divided into normal and dyslipidaemia groups. The latter included 7 subgroups as follows: low high density lipoprotein (L-HDL)-subgroup I, high triglycerides (H-TG)-subgroup II, high total cholesterol or high low density lipoprotein (H-TC/H-LDL)-subgroup III, low high density lipoprotein with high triglycerides (L-HDL + H-TG)-subgroup IV, low high density lipoprotein with high total cholesterol or high low density lipoprotein (L-HDL + H-TC/H-LDL)-subgroup V, high triglycerides with high total cholesterol or high low density lipoprotein(H-TG + H-TC/H-LDL)-subgroup VI, low high density lipoprotein with high triglycerides and high total cholesterol or high low density lipoprotein (L-HDL + H-TG + H-TC/H-LDL)-subgroup VII. Homeostasis model assessment (HOMA) was applied to estimate the degree of insulin resistance (IR). RESULTS: (1) Adjusted with age, sex and body mass index (BMI), HOMA-IR was increased in the dyslipidaemia subgroups with high triglycerides. (2) Hypertriglyceridemia was more closely related to raised BMI and waist-hip ratio (WHR). (3) Both body fat (BMI, WHR) and triglycerides were independent risk factors accounting for HOMA-IR. CONCLUSION: Hypertriglycerides could be regarded as an independent risk factor for insulin resistance.

Adult↗
PubMed2001

[Study on chemical constituents of Dendranthema morifolium by GC-MS].

OBJECTIVE: To analyse chemical constituents of volatile oil from Dendranthema morifolium Tzvel. et Zhao. by GC-MS. METHODS: The volatile oil was extracted from Dendranthema morifolium Tzvel. et Zhao. by steam distillation and were analysed by different kinds of capillary columns to find out the optimal conditions. The content of compositions of volatile oil were determined by normalization method. And the constituents were identified by GC-MS. RESULTS: 41 components were separated and identified which accounted for over 73% of total volatile oil. CONCLUSIONS: The main constituents in the essential oils from Dendranthema morifolium Tzvel. et Zhao are verbenol, (-)-zingiberene, beta-sesquiphellandrene, farnesene, tau.-cadinol and tau.-muurolol.

Asteraceae↗
PubMed2001

Regulative effect of P38MAPK on release of TNFalpha and NO from alveolar macrophages under endotoxin stimulation.

OBJECTIVE: To evaluate activation of P38 mitogen-activated protein kinase (P38MAPK) in alveolar macrophage (AM), release of TNFalpha and NO from cells, and their relationship following lipopolysaccharide (LPS) stimulation. METHODS: AM was isolated from branch alveolar lavage fluid (BALF). The activation of P38MAPK was assayed by Western blot. SB203580, a specific inhibitor of P38MAPK, was used with gradient concentration to evaluate the regulative effect of P38MAPK on the release of TNFalpha and NO from AM. RESULTS: P38MAPK was activated by LPS (100 ng/ml) with peak activation at 30 minutes. The activation of P38MAPK was inhibited by SB203580. The secretion of TNFalpha and NO stimulated with LPS increased (P<0.01) and was inhibited by SB203580 significantly. CONCLUSIONS: The results indicate that P38MAPK is involved in the secreting process of TNFalpha and NO following LPS stimulation. P38MAPK may be an important site for controlling the secretion of both inflammatory mediators during lung inflammatory disorders.

Animals↗
PubMed2001

[Detection of anti-HAV, anti-HBV, anti-HCV and anti-HEV antibodies in the patients with sporadic acute hepatitis in Beijing during 1995-2000].

BACKGROUND: To investigate distribution of acute hepatitis A, hepatitis B, hepatitis C and hepatitis E in Beijing area. METHODS: Enzyme immunoassay (EIA) was used for detection of anti-HAV immunoglobulin M (IgM), HBsAg/anti-HBc IgM, anti HCV IgM/IgG and anti-HEV IgM/IgG. The samples were collected from the patients with sporadic hepatitis in Beijing city between 1995 and 2000. RESULTS: The total positive rate of IgM antibodies to the four hepatitis-viruses was 72.4% (155) among 214 patients with sporadic acute hepatitis; the positive rates for the 4 viruses were 29% (45) for anti-HAV, 18.1% (28) for anti-HBc, 3.9% (6) for anti-HCV and 49% (76) for anti-HEV among 155 patients with acute viral hepatitis. Nine patients were coinfected with two hepatitis viruses. CONCLUSIONS: 78% of patients with sporadic acute hepatitis were caused by enterically transmitted hepatitis viruses (A and E) in Beijing between 1995 and 2000, Hepatitis E had the highest rate. Coinfection with two hepatitis virus was found in the patient with intravenous drug abusers and cirrhosis or acute hepatitis.

Acute Disease↗
PubMed2001

[Fermentation conditions for production of alkaline elastase by alkaliphilic Bacillus XE22-4-1].

A extracellular alkaline elastase producing bacterial strain Bacillus XE22-4-1, with the optimum pH of 10.0 for its growth, was isolated and screened from alkali lake of Tibet. 2% glucose and 0.25% yeast extract are respectively the appropriate carbon and nitrogen source on elastase production. Soymeal can promote elastase production. The fermentation conditions in a 2 L stirred tank were investigated. The results have revealed that the dissolved oxygen is the most effective factor on elastase production. The maximum elastolytic activity reached 266 u/mL among 48 hours of fermentation by combination of enhancing aeration and changing the mixing speed.

Bacillus↗
PubMed2001

[Identification and cloning of partial mbh2 gene cluster of hyperthermophile Aquifex pyrophilus].

A 0.8 kb fragment of mbhS2 gene of Aquifex pyrophilus was obtained by PCR with designed primers basing mbhS2 gene of A. aeolicus. It showed 85% homology with the corresponding region of A. aeolicus. Using it as probe, a 5.0 kb Nco I fragment was fished out from the partial genomic library of A. pyrophilus. Then this fragment was cloned, subcloned and sequenced. The result revealed that the fragment contains the full length gene for the mbhS2, the gene orf1 and the first 366 bp of orf2. Comparison with mbhS2 and orf963 of A. aeolicus shows 81% and 60% homologies in amino acid sequence, respectively.

Amino Acid Sequence↗
PubMed2001

[Effect of KB-R7943 on Na(+)-Ca2+ exchange current in guinea pig ventricular myocytes].

AIM: To study whether KB-R7943 has selective inhibitory effect on the inward and outward Na(+)-Ca2+ exchange current (INa-Ca) in guinea pig ventricular myocytes. METHODS: Through setting up the model of intracellular Na(+)-overload during myocardial ischemia and reperfusion, the current-voltage relationship of INa-Ca was recorded using whole-cell patch clamp technique under bi-directional ionic conditions. RESULTS: Currents were elicited by a declining ramp pulse depolarized immediately from holding potential of -40 mV to +60 mV, then repolarized to -100 mV at a speed of 80 mV.s-1 and returned to the holding potential under bi-directional ionic conditions, while the [Na+] was 25 mmol.L-1 in the pipette solution. The currents increased time-dependently and voltage-dependently which reached from (2.51 +/- 0.15) pA.pF-1 to (5.94 +/- 0.13) pA.pF-1 at mV and from (-1.92 +/- 0.13) pA.pF-1 to (-3.17 +/- 0.16) pA.pF-1 at -80 mV (n = 12) after 3 min and there is no significant run-down of the current. KB-R7943 10(-6) mol.L-1 was found to decrease the current to (4.62 +/- 0.05) pA.pF-1 by 29.4% at mV and to (-2.30 +/- 0.18) pA.pF-1 by 22.1% at -80 mV (n = 5) after 5 min. While 10(-5) mol.L-1 KB-R7943 was shown to decrease the current to (3.13 +/- 0.03) pA.pF-1 by 61.7% at mV and to (-1.62 +/- 0.03) pA.pF-1 by 56.9% at -80 mV (n = 7). CONCLUSION: KB-R7943 can block INa-Ca in guinea pig ventricular myocytes. But, it did not show selective inhibition effect on inward and outward currents.

Animals↗
PubMed2001

[An integrated medical diagnostic X-ray unit controlled by microcomputer].

This article introduces an integrated medical diagnostic X-ray unit controlled by microcomputer. It is a practical and low-priced spot-film radiography device, and it is applicable to conventional local control unit. If you select a set of X-rayimage intensification, it can be remotely controlled. This device utilizes DC servo motor and fine precision feedback variable resistor and closed loop control so it has the advantage of fine static control and low mechanical noise. The whole radiographic process is automatically controlled by microcomputer, and can be operated easily.

Equipment Design↗
PubMed2001

[The development of cerebral circulation analyzer].

In this paper a new cerebral circulation analyzer is introduced, inducing the main structure, the operating principle, the software program and its clinical applications. We can get the cerebrovascular hemodynamics indexes such as resistance, compensatorg blood flow etc., from the blood velocity, pressure waveform, and arterial diameter detected in carotid and vertebral arteries.

Algorithms↗