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Biomedical subjects

X J Liu

Publications and source records attributed to X J Liu.

At least 37 records · Page 2Linked to original sources
PubMed2001

Clinical outcome of patients with previous myocardial infarction and left ventricular dysfunction assessed with myocardial (99m)Tc-MIBI SPECT and (18)F-FDG PET.

UNLABELLED: Myocardial viability was assessed by (99m)Tc-methoxyisobutylisonitrile (MIBI) SPECT and (18)F-FDG PET to evaluate the prognosis and treatment strategy of patients with myocardial infarction (MI) and left ventricular (LV) dysfunction. METHODS: One hundred twenty-three consecutive patients with previous MI and LV dysfunction (LV ejection fraction [EF], 35% +/- 6% [mean +/- SD]) who underwent (99m)Tc-MIBI SPECT and FDG PET were followed-up for 26 +/- 10 mo (mean +/- SD). Distributions of the 2 radiotracers in myocardial segments were classified into 2 patterns: myocardial perfusion-metabolism mismatch (MM) and match (M). LV EF and LV end-diastolic diameter (EDD) were measured by echocardiography at baseline, 3 mo (Pos1), and 6 mo (Pos2) after revascularization. Cardiac death, acute MI, unstable angina, and late revascularization (>3 mo) experienced by the patients during follow-up were defined as cardiac events. RESULTS: Sixty-seven patients underwent revascularization and 56 patients were treated medically. Of the 72 patients with > or =2 MM segments, 42 underwent revascularization (group A1) and 30 were treated medically (group A2). Of the 51 patients with <2 MM segments, 25 underwent revascularization (group B1) and 26 were treated medically (group B2). The 4 groups had similar baseline characteristics and rest LV EF. After revascularization, EF (mean +/- SD) increased in group A1 from 36% +/- 5% to 44% +/- 8% (P < 0.0001) in Pos1 and to 51% +/- 9% (P < 0.0001) in Pos2. EDD (mean +/- SD) decreased from 62 +/- 8 mm to 56 +/- 5 mm (P < 0.001) in Pos1 and to 55 +/- 5 mm (P < 0.001) in Pos2. However, EF and EDD were unchanged in group B1 (P > 0.05). During the follow-up, 22 patients (17.9%) suffered from cardiac events, including 11 cardiac deaths, 4 acute MI, 6 late coronary artery bypass grafting, and 1 unstable angina pectoris. The cardiac event rate in group A2 (50%) was significantly higher than that of groups A1 (2.4%; chi(2) = 23.08; P < 0.0001), B1 (12%; chi(2) = 8.94; P = 0.003), and B2 (11.5%; chi(2) = 9.45; P = 0.002). CONCLUSION: Assessment of myocardial viability using hybrid (99m)Tc-MIBI SPECT and FDG PET can predict the clinical outcome and is helpful to decision making in the treatment strategy of patients with MI and LV dysfunction. Revascularization can improve the LV function and clinical outcome of patients with >2 viable myocardial segments.

Aged↗
PubMed2001

Naltrexone microspheres: in vitro release and effect on morphine analgesia in mice.

AIM: To study in vitro release and in vivo effect of four different types of sustained-release naltrexone microspheres on morphine analgesia. METHODS: Release of naltrexone from four types of biodegradable microspheres was investigated by HPLC. Their antagonist effects on morphine analgesia were observed using mouse hot-plate procedure. RESULTS: Poly latide-co-glycolide (PLGA) composition had a remarkable effect on naltrexone release from microspheres and its antagonism towards morphine analgesia. Two formulations of PLGA 50:50 formulation released more than 80 % of total naltrexone and lost their antagonism by 8 d. The PLGA 75:25 formulation with 20 % and 30 % drug loadings did not release 95 % of total drug and lose antagonism until 40 d and 30 d, respectively. Increasing the drug loading enhanced naltrexone release from microspheres and seemed to shorten the analgesic antagonistic effect of naltrexone. CONCLUSION: Antagonism by naltrexone microspheres towards morphine analgesia correlates well with the drug release in vitro.

Analgesia↗
PubMed2001

[Distribution of MICA microsatellite in 13 population groups of China].

The genetic data of MICA microsatellite were obtained by genotyping 577 samples in 13 population groups of China, which are Han-YN, Han-GD, Han-SD, Bai, Dai, Lahu, Li, Naxi, Sala, She, Tu, Wa and Zang-YN, with genescan. Five alleles have been observed in the population groups, which are A4, A5, A5.1, A6 and A9. A5 allele is the most frequent in all population groups except Lahu and Li, while the most frequent allele for Lahu and Li is A5. 1 and A4 respectively. The second most frequent allele is the A5.1 in Han-YN, Han-SD, Dai, Naxi, Sala, She, and Wa. The lest frequent allele for Han-YN, Han-GD, Lahu, Naxi, She, Wa is the A6 which is not observed in Li. A4 allele is the lest frequent in Han-SD, Bai, Dai, Sala, Tu, Zang-YN. The results show that the distribution of MICA microsatellite is different in these population groups, and the polymorphism information contents (PIC) of this microsatellite is high. It is a potential useful marker in the study of human origin and migration, personal identification, gene mapping and location, and disease diagnosis.

China↗
PubMed2001

[Study on application of CODIS loci to excluding paternity].

OBJECTIVE: The study was carried out on application of CODIS loci (FGA, vWA, CSF1PO, TH01, TPOX, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51 and D21S11) in 100 cases of excluding paternity. METHODS: The PCR amplified products of Profiler Plus and Cofiler amplification kit were injected into a capillary on the ABI PRISM 310 Genetic Analyzer. GeneScan software analyzed the collected data, which can then be imported into Genotyper software for genotyping of alleles. RESULTS: In the group of Mother-Child-Alleged Father, more than 3 STR loci incompatibilities between alleged father and child were found in all observed cases, the mean incompatibility was 6.63; In the group of Alleged Father-Child, 94.0% of all cases observed was found more than 3 STR loci incompatibilities, the mean incompatibility was 5.01. CONCLUSION: The results showed that CODIS loci had good application to excluding paternity, and the choice of hyperpolymorphic markers in investigation, which were valued by DP, H and PE, had direct relation with the augmentation of incompatibilities in excluding paternity.

Adult↗
PubMed2001

[Inhibitory effect of boanmycin on the growth of colon carcinoma 26 and hepatic metastasis in mice].

AIM: To investigate the therapeutic effect of boanmycin (BAM, bleomycin A6) on colon carcinoma 26 and its hepatic metastasis in mice. METHODS: A series of models including subcutaneous transplantation, orthotopic transplantation in cecum subserosa, intra-hepatic transplantation of tumor, and intrasplenic transplantation of tumor accompanied with hepatic metastases were employed. In addition, LEICA Q 500IW image analysis system was used to determine the area of metastatic lesions in the liver in histopathological sections. RESULTS: BAM at 5 mg.kg-1 and 2.5 mg.kg-1 inhibited the growth of subcutaneous tumors by 78.7% and 61.9%, and the orthotopic tumors by 99.4% and 90.0%; and the intra-hepatic tumors by 86.9% and 75.7%, respectively. Determined by the numbers of metastatic nodules, BAM at 10 mg.kg-1 and 5 mg.kg-1 inhibited hepatic metastases from intra-splenic transplantation by 97.6% and 56.8%; and evaluated by image analysis of metastatic lesions, by 100% and 63.3%, respectively. CONCLUSION: Boanmycin is highly effective in a panel of models including the subcutaneous, orthotopic, intra-hepatic transplanted tumors, and hepatic metastases of murine colon carcinoma 26.

Animals↗
PubMed2001

[Treatment of hemangioma in oral and maxillofacial region with intralesional injection of pingyangmycin].

OBJECTIVE: To investigate the indication and long term treatment results of intralesional injection of Pingyangmycin for hemangiomas in oral and maxillofacial regions. METHODS: Between June 1986 and June 2000, 1040 patients with maxillofacial hemangiomas were treated by intralesional injection of Pingyangmycin PYM . There were 312 males and 712 females. The types of hemangiomas included capillary 436, cavernous 238, mixed 260, arterial venous malformation 8 and port wine stain 9 . The injection was performed in stages and multi sites, repeated after 14 to 21 days for 2 to 3 times as one course. RESULTS: All the patients were followed up for 1 to 14 years. The cure rates of capillary, mixed and cavernous hemangioma were 96.40%, 92.20% and 67.20%, respectively. No effect was found for arterial venous malformations. The best dose effect was attained in 1mg/cm(2). The best concentration of Pingyangmycin was 1mg/ml for capillary hemangioma and the concentration may be higher for cavernous hemangiomas. Fever occurred in 6.54% of the cases. Serious complications associated with Pingyangmycin injection, such as pulmonary fibrosis were not found. CONCLUSION: Intralesional injection of Pingyangmycin can be used as the therapy of choice for capillary, mixed and cavernous hemangiomas in oral and maxillofacial region. The advantages included a high cure rate, safety, short course, manipulation with ease and fewer side effects.

English Abstract↗
PubMed2000

Potentiation of formalin-evoked adenosine release by an adenosine kinase inhibitor and an adenosine deaminase inhibitor in the rat hind paw: a microdialysis study.

The present study examined the effects of local subcutaneous administration of formalin on adenosine release from the rat hind paw, and the effects of inhibitors of adenosine metabolism on such release. Microdialysis probes were inserted into the subcutaneous tissue of the plantar surface of rat hind paws. Samples were collected every 10 min at a perfusion rate of 2 microl/min and high performance liquid chromatography was used to measure adenosine levels. At lower concentrations of formalin (0.5-2.5%), a significant increase in adenosine levels was observed in the first 10 min after formalin injection, while at the highest concentration of formalin (5%), the increase in adenosine release was observed over 60 min. Co-administration of the adenosine kinase inhibitor 5'-amino-5'-deoxyadenosine (100 nmol) with formalin, significantly increased adenosine release evoked by 0.5-1.5% formalin, but did not produce a further enhancement of release evoked by 5% formalin. The adenosine deaminase inhibitor 2'-deoxycoformycin (100 nmol) significantly increased adenosine levels at 5% formalin but had no effect at lower concentrations of formalin. In confirmation of previous studies, subcutaneous injection of formalin (0.5-5%) produced a characteristic biphasic concentration-related expression of nociceptive behaviours and an increase in paw volume. This study directly demonstrates that formalin can evoke a concentration-dependent local release of adenosine from the rat hind paw. The ability of an adenosine kinase inhibitor and an adenosine deaminase inhibitor to modulate this release is dependent on substrate adenosine concentrations.

Adenosine↗
PubMed2000

The classical progesterone receptor mediates Xenopus oocyte maturation through a nongenomic mechanism.

Xenopus laevis oocytes are physiologically arrested at G(2) of meiosis I. Resumption of meiosis, or oocyte maturation, is triggered by progesterone. Progesterone-induced Xenopus oocyte maturation is mediated via an extranuclear receptor and is independent of gene transcription. The identity of this extranuclear oocyte progesterone receptor (PR), however, has remained a longstanding problem. We have isolated the amphibian homologue of human PR from a Xenopus oocyte cDNA library. The cloned Xenopus progesterone receptor (xPR) functioned in heterologous cells as a progesterone-regulated transcription activator. However, endogenous xPR was excluded from the oocyte nucleus and instead appeared to be a cytosolic protein not associated with any membrane structures. Injection of xPR mRNA into Xenopus oocytes accelerated the progesterone-induced oocyte maturation and reduced the required concentrations of progesterone. In enucleated oocytes, xPR accelerated the progesterone-induced mitogen-activated protein kinase activation. These data suggest that xPR is the long sought after Xenopus oocyte receptor responsible for progesterone-induced oocyte maturation.

Animals↗
PubMed2000

Involvement of mast cells, sensory afferents and sympathetic mechanisms in paw oedema induced by adenosine A(1) and A(2B/3) receptor agonists.

Both the adenosine A(1) receptor agonist N(6)-cyclopentyladenosine and the adenosine A(2B/3) receptor agonist N(6)-benzyl-5'-N-ethylcarboxamido adenosine (N(6)-B-NECA) produce an acute paw oedema response following local s.c. injection into the rat hindpaw. This study characterized aspects of the mechanisms by which these responses occur by determining the effect of compound 48/80 (mast cell depleting agent), capsaicin (sensory neurotoxin) and 6-hydroxydopamine (sympathetic nervous system neurotoxin) on the paw oedema response produced by these agents. Compound 48/80 markedly reduced the increase in paw volume produced by both N(6)-cyclopentyladenosine and N(6)-B-NECA. Capsaicin significantly reduced paw oedema induced by N(6)-cyclopentyladenosine but not N(6)-B-NECA. In contrast, 6-hydroxydopamine reduced paw oedema induced by N(6)-B-NECA but not N(6)-cyclopentyladenosine. These results indicate an involvement of mast cells in paw oedema produced by both adenosine A(1) and A(2B/3) receptor agonists. For N(6)-cyclopentyladenosine, this involvement may be a secondary involvement due to activation of a neurogenic mechanism, but for N(6)-B-NECA, it may be a direct effect on mast cells. The nature of the involvement of the sympathetic nervous system in the action of N(6)-B-NECA is not entirely clear.

Adenosine↗
PubMed2000

Xenopus laevis TRK-fused gene (TFG) is an SH3 domain binding protein highly expressed in the cement gland.

TRK-fused gene (TFG) was originally identified in humans as the N-terminus of an oncogenic fusion protein TRK-T3, associated with papillary thyroid carcinoma. An amino-terminal coiled coil domain of TFG is responsible for mediating oligomerization of the TRK-T3 oncoprotein, resulting in constitutive activation of the TRK protein tyrosine kinase and oncogenesis. We have cloned the Xenopus laevis homologue of TFG and demonstrated that xTFG was highly expressed in the cement gland of tailbud embryos. Overexpression of xTFG2-136 (including the coiled coil domain) in early embryos, via mRNA microinjection as well as transgenic expression using the recently described restriction enzyme mediated integration (REMI) transgenesis, did not alter embryonic development or development of a functional cement gland, despite clear evidence that xTFG2-136 strongly interacted with endogenous xTFG. Finally, we have identified a potential SH3 binding motif in xTFG (and in TFG) and have demonstrated that xTFG selectively interacted with SH3 domains of Src, PLCgamma, and the p85 phosphatidylinositol 3-kinase subunit.

Amino Acid Sequence↗
PubMed2000

Support vector machines for prediction of protein subcellular location.

Support Vector Machine (SVM), which is one kind of learning machines, was applied to predict the subcellular location of proteins from their amino acid composition. In this research, the proteins are classified into the following 12 groups: (1) chloroplast, (2) cytoplasm, (3) cytoskeleton, (4) endoplasmic reticulum, (5) extracall, (6) Golgi apparatus, (7) lysosome, (8) mitochondria, (9) nucleus, (10) peroxisome, (11) plasma membrane, and (12) vacuole, which have covered almost all the organelles and subcellular compartments in an animal or plant cell. The examination for the self-consistency and the jackknife test of the SVMs method was tested for the three sets: 2022 proteins, 2161 proteins, and 2319 proteins. As a result, the correct rate of self-consistency and jackknife test reaches 91 and 82% for 2022 proteins, 89 and 75% for 2161 proteins, and 85 and 73% for 2319 proteins, respectively. Furthermore, the predicting rate was tested by the three independent testing datasets containing 2240 proteins, 2513 proteins, and 2591 proteins. The correct prediction rates reach 82, 75, and 73% for 2240 proteins, 2513 proteins, and 2591 proteins, respectively.

Algorithms↗
PubMed2000

A comparison of 99Tcm-MIBI myocardial SPET and electron beam computed tomography in the assessment of coronary artery disease in two different age groups.

The aim of this study was to compare the clinical value of 99Tcm-MIBI single photon emission tomography (SPET) and electron beam computed tomography (EBCT) in the assessment of coronary artery disease (CAD) in different age groups. 99Tcm-MIBI SPET (stress-rest), EBCT and coronary angiography studies were performed in 64 consecutive patients with suspected CAD. The patients were classified into two groups: Group A = 40 patients > 45 years of age and Group B = 24 patients < or = 45 years of age. There were 31 and 14 patients with coronary stenosis > or = 50% as determined by coronary angiography in Groups A and B, respectively. All patients (30 cases) with abnormal 99Tcm-MIBI myocardial SPET and coronary calcification detected by EBCT had significant coronary artery disease, and 93.3% of the patients with normal 99Tcm-MIBI SPET and normal EBCT had normal coronary angiography or < 50% lumen narrowing of the coronary arteries. In Group B, the sensitivity of SPET for detecting CAD was significantly higher than that of EBCT (92.9 vs 42.9%, P < 0.01); the specificity of SPET was comparable to that of EBCT. In Group A, there was no significant difference between SPET and EBCT in terms of sensitivity (93.6 vs 90.3%) or specificity (88.9 vs 55.6%). However, in the detection of individual coronary artery disease, the specificity of SPET was significantly higher than that of EBCT in Group A (94.1 vs 66.7%, P < 0.001). The sensitivity of SPET was again significantly higher than that of EBCT (85.7 vs 38.1%, P < 0.005) in Group B. The accuracy of SPET was higher than that of EBCT in both groups (82.5 vs 67.5%, P < 0.01 in Group A; 93.1 vs 76.4%, P < 0.01 in Group B, respectively). We conclude that 99Tcm-MIBI myocardial perfusion SPET has a higher sensitivity than EBCT in the detection of CAD in patients < or = 45 years old and a higher specificity in patients > 45 years of age. A combination of SPET and EBCT may assess CAD more accurately.

Adult↗
PubMed2000

Selective impairment of corticotropin-releasing factor1 (CRF1) receptor-mediated function using CRF coupled to saporin.

CRF is the main component in the brain neuropeptide effector system responsible for the behavioral, endocrine, and physiological activation that accompanies stress activation. Reduced CRF system activation plays a role in the etiology of a variety of psychiatric and metabolic disease states. We have developed a novel protein conjugate that joins native rat/human CRF to a ribosome-inactivating protein, saporin (CRF-SAP), for the purpose of targeted inactivation of CRF receptor-expressing cells. Cytotoxicity measurements revealed that CRF-SAP (1-100 nM) produced concentration-dependent and progressive cell death over time in CRF1 receptor-transfected L cells, but at similar concentrations had no effect on CRF2alpha receptor-transfected cells. The CRF-SAP-induced toxicity in CRF1-transfected cells was prevented by coincubation with the competitive CRF1/CRF2 receptor peptide antagonist, [D-Phe12]CRF-(12-41), or the selective nonpeptide CRF1 receptor antagonist, NBI 27914. Finally, in cultured rat pituitary cells that express native CRF1 receptors, CRF-SAP suppressed CRF-induced (1 nM) ACTH release. GnRH (1-10 nM) stimulated LH release was also assessed in the same pituitary cultures. Although there was a slight decrease in LH release from these cultures, this decrease was observed with CRF-SAP or SAP alone, suggesting that the response was nonspecific. Taken together, these results suggest the utility of CRF-SAP as a specific and subtype-selective tool for long term impairment of CRF1 receptor-expressing cells.

Adrenocorticotropic Hormone↗
PubMed2000

[Potential exposure to inorganic mercury in people living near a sewage sludge dumping site: urinary excretion of mercury, subjective symptoms and renal function].

OBJECTIVE: The purpose of this study was to evaluate the presence of exposure to inorganic mercury and its health effects among people living near a sewage sludge dumping site in Nagasaki Prefecture, Japan. In this area, sewage sludge and industrial waste have been dumped since 1975, and total mercury levels exceeding the water quality standards (0.0006-0.0020 mg/l) have been detected in seeping water and river water since July 1997. METHODS: The population for the present study comprised 48 subjects (aged 11-91 years) living near a sewage sludge dumping site and 49 subjects (aged 10-82 years) living in a non-polluted area. In November and December 1998, subjective symptoms of inorganic mercury exposure, history of occupational exposure to inorganic mercury, frequency of fish intake, sources of drinking water and other health habits were inquired by a self-administered questionnaire. Total mercury and total protein levels and N-acetyl-beta-D-glucosaminidase (NAG) activity in morning urine specimens were also measured. RESULTS: Among males, the proportion of subjects who complained of tremor in the hands (P = 0.02) and increased irritability (P = 0.10) was higher in the polluted area than in the control area. In addition, the proportion of those who did not report being easily fatigued was lower in the polluted area than in the control area (P = 0.07). Among females there was no significant difference in the prevalence of self-reported symptoms related to the central nervous system disturbance between the two areas. After adjustment for gender and age using logistic regression analysis, the prevalence of increased irritability was significantly higher (P = 0.05) and the proportion of those who did not report being easily fatigued was significantly lower (P = 0.03) in the polluted area than in the control area. However, there was no significant difference in the geometric mean of urinary total mercury concentration (microgram/g creatinine) between the polluted area (0.66, 95% confidence interval [CI] 0.48-0.91 for men and 0.96, 95% CI 0.70-1.33 for women) and the control area (0.81, 95% CI 0.60-1.09 for men and 0.83, 95% CI 0.57-1.22 for women). There was no individual whose total mercury concentration in urine exceeded 30 micrograms/g creatinine, at which level of urinary total mercury toxic effects on the central nervous system have been reported in industrial workers. There was also no significant difference in the geometric means of urinary total protein level and NAG activity. CONCLUSION: There was no evidence of excessive exposure to inorganic mercury among residents in the polluted area. Thus, we concluded that the difference in the prevalence of subjective symptoms was not due to the direct effect of exposure to inorganic mercury. To prevent the contamination of water by taking measures against pollution sources, monitoring of the quality of drinking water, and finally to secure safe water supply by public waterworks are required.

Adolescent↗
PubMed1999

Acute paw oedema induced by local injection of adenosine A(1), A(2) and A(3) receptor agonists.

The present study used plethysmometry to examine oedema following local injection of selective adenosine A(1), A(2) and A(3) receptor agonists and inhibitors of adenosine metabolism into the hindpaw of the rat. N(6)-Cyclopentyladenosine and L-N(6)-phenylisopropyladenosine (A(1)), 2-[p(2-carboxyethyl) phenethylamino]-5'-N-ethylcarboxamidoadenosine hydrochloride (CGS21680) (A(2A)) and N(6)-benzyl-5'-N-ethylcarboxamido adenosine (N(6)-B-NECA) (A(3)) all produced an increase in paw volume (N(6)N(6)-cyclopentyladenosine, L-N(6)CGS21680). At the highest dose, each agent also produced a systemically mediated suppression of oedema. Oedema by N(6)-cyclopentyladenosine was blocked by caffeine, 8-cyclopentyl-1,3-dimethylxanthine and enprofylline. Oedema by CGS21680 was blocked by caffeine and 8-cyclopentyl-1, 3-dimethylxanthine. Oedema by N(6)-B-NECA was blocked by enprofylline, but not by caffeine or 8-cyclopentyl-1, 3-dimethylxanthine, or by systemic administration of MRS 1191. Oedema by both N(6)-cyclopentyladenosine and N(6)-B-NECA was blocked by mepyramine, ketanserin and phentolamine, but that by CGS21680 was not. The adenosine kinase inhibitor 5'-amino-5'-deoxyadenosine and the adenosine deaminase inhibitor 2'-deoxycoformycin produced only a limited increase in paw volume, and this was blocked by caffeine. This study demonstrates an acute paw oedema response following local administration of adenosine A(1), A(2) and A(3) receptor agonists, which likely results from different mechanisms of action in each case.

Acute Disease↗
PubMed1999

Nephroblastoma overexpressed gene (NOV) codes for a growth factor that induces protein tyrosine phosphorylation.

NOV (nephroblastoma overexpressed gene) is a member of the CCN (connective tissue growth factor [CTGF], Cyr61/Cef10, NOV) family of proteins. These proteins are cysteine-rich and are noted for having growth-regulatory functions. We have isolated the rat NOV gene, and the DNA sequence shares 90% identity with the mouse and 80% identity with the human sequences. The rat NOV gene was expressed in all rat tissues examined, including brain, lung, heart, kidney, liver, spleen, thymus and skeletal muscle. Higher levels of rat NOV mRNA were seen in the brain, lung and skeletal muscle compared to the other tissues. Examination of NOV expression in various human cell lines revealed that NOV was expressed in U87, 293, T98G, SK-N-MC and Hs683 but not in HepG2, HL60, THP1 and Jurkat. The human NOV gene was transfected into 293 cells and the expressed protein purified. When 3T3 fibroblasts were treated with this recombinant NOV protein, a dose-dependent increase in proliferation was observed. Analysis of tyrosine-phosphorylated proteins revealed that when 3T3 cells were treated with NOV, a 221 kDa protein was phosphorylated. These data suggest that NOV can act as a growth factor for some cells and binds to a specific receptor that leads to the phosphorylation of a 221 kDa protein.

3T3 Cells↗