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Biomedical subjects

Y L Li

Publications and source records attributed to Y L Li.

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

Impairment of endothelial function after a high-fat meal in patients with coronary artery disease.

OBJECTIVE: To determine the effect of postprandial lipid changes on endothelial function in patients with coronary artery disease (CAD) after a high-fat meal. METHODS: We studied 50 CAD patients and 25 control participants, who were all normocholesterolemic. Flow-mediated vasodilatation of the brachial artery was evaluated by the high-resolution ultrasound technique before and after a single high-fat meal (800 calories; 50 g fat). RESULTS: Postprandial serum triglyceride level increased significantly at 2-7 h and mean flow-mediated vasodilatation was impaired significantly (from 4.22 +/- 0.44 to 2.75 +/- 0.33%, P < 0.01) for 75 subjects. The increment in 2 h serum triglyceride level correlated positively with the decrement in postprandial flow-mediated vasodilatation (r = 0.459, P < 0.01). Postprandial triglyceride level was significantly higher in CAD patients than in control participants. Flow-mediated vasodilatation was significantly impaired in CAD patients (from 3.04 +/- 0.39 to 1.69 +/- 0.23%, P < 0.01) and control participants (from 6.58 +/- 0.52 to 4.87 +/- 0.19%, P < 0.05) after a high-fat meal. The impairment of flow-mediated dilatation was more severe in CAD patients (44.41%) than in control participants (25.99%, P < 0.01). CONCLUSION: Postprandial endothelium-dependent vasodilatation after a single high-fat meal was severely impaired in normocholesterolemic CAD patients and control participants. The disordered postprandial metabolism of triglyceride-rich lipoproteins may play an atherogenic role by inducing endothelial dysfunction.

Adult↗
PubMed2001

Experimental research on TECA-I bioartificial liver support system to treat canines with acute liver failure.

AIM: To evaluate the efficacy and safety of the TECA-I bioartificial liver support system (BALSS) in treating canines with acute liver failure (ALF). METHODS: Ten canines with ALF induced by 80% liver resection received BALSS treatment (BALSS group). Blood was perfused through a hollow fiber tube containing 1X10(10) porcine hepatocytes. Four canines with ALF were treated with BALSS without porcine hepatocytes (control group), and five canines with ALF received drug treatment (drug group). Each treatment lasted 6 hours. RESULTS: BALSS treatment yielded beneficial effects for partial liver resection induced ALF canines with survival and decreased plasma ammonia, ALT, AST and BIL. There was an obvious decrease in PT level and increase in PA level, and there were no changes in the count of lymphocytes, immunoglobulins (IgA, IgG and IgM) and complement (C3 and C4) levels after BALSS treatment. In contrast, for the canines with ALF in non-hepatocyte BALSS group (control group) and drug group, there were no significant changes in ammonia, ALT, AST, BIL, PT and PA levels. ALF canines in BALSS group, control group and drug group lived respectively an average time of 108.0h +/- 12.0h, 24.0h +/- 6.0h and 20.4h +/- 6.4h,and three canines with ALF survived in BALSS group. CONCLUSION: TECA-I BALSS is efficacious and safe for ALF canines induced by partial liver resection.

Animals↗
PubMed2001

TECA hybrid artificial liver support system in treatment of acute liver failure.

AIM: To assess the efficacy and safety of TECA type hybrid artificial liver support system (TECA-HALSS) in providing liver function of detoxification, metabolism and physiology by treating the patients with acute liver failure (ALF). METHODS: The porcine liver cells (1-2) x 10(10) were separated from the Chinese small swine and cultured in the bioreactor of TECA-BALSS at 37.0 degrees C and circulated through the outer space of the hollow fiber tubes in BALSS. The six liver failure patients with various degree of hepatic coma were treated by TECA-HALSS and with conventional medicines. The venous plasma of the patients was separated by a plasma separator and treated by charcoal adsorbent or plasma exchange. The plasma circulated through the inner space of the hollow fiber tubes of BALSS and mixed with the patients' blood cells and flew back to their blood circulation. Some small molecular weight substances were exchanged between the plasma and porcine liver cells. Each treatment lasted 6.0-7.0 h. Physiological and biochemical parameters were measured before,during and after the treatment. RESULTS: The average of porcine liver cells was (1.0-3.0) x 10(10) obtained from each swine liver using our modified enzymatic digestion method. The survival rate of the cells was 85%-93% by trypan blue stain and AO/PI fluorescent stain. After cultured in TECA-BALSS bioreactor for 6 h, the survival rate of cells still remained 70%-85%. At the end of TECA-HALSS treatment, the levels of plasma NH(3), ALT, TB and DB were significantly decreased. The patients who were in the state of drowsiness or coma before the treatment improved their appetite significantly and regained consciousness, some patients resumed light physical work on a short period after the treatment. One to two days after the treatment, the ratio of PTA increased warkedly. During the treatment, the heart rates, blood pressure, respiration condition and serum electrolytes (K(+), Na(+) and Cl(-)) were stable without thrombosis and bleeding in all the six patients. CONCLUSION: TECA-HALSS treatment could be a rapid, safe and efficacious method to provide temporary liver support for patients with ALF.

Acute Disease↗
PubMed2001

[Cellular compatibility of three natural xenogeneic bone derived biomaterials].

OBJECTIVE: To evaluate the cellular compatibility of three natural xenogeneic bone derived biomaterials. METHODS: Three types of natural xenogeneic bone derived biomaterials were made with physical and chemical treatment, composite fully deproteinized bone(CFDB), partially deproteinized bone(PDPB) and partially decalcified bone(PDCB). Three types biomaterials were cocultured with human embryonic periosteal osteoblasts. The cell growth, attachment, cell cycle, alkaline phosphatase activity were detected to evaluate the cellular compatibility to biomaterials. RESULTS: Osteoblasts attached on all three biomaterials and grew well, the effect of three biomaterials on cell proliferation was PDCB > PDPB > CFDB. The cell cycle was not obviously affected by three biomaterials. The effect of three biomaterials on alkaline phosphatase activity of osteoblasts was PDCB > PDPB > CFDB. CONCLUSION: CFDB,PDPB,PDCB have good cellular compatibility without cytotoxic and tumorigenicity, CFDB is the best. The three biomaterials can be used as scaffold materials of bone tissue engineering.

Bone Substitutes↗
PubMed2001

[Investigation of genotyping HLA DRB1 gene using oligoneucleotide arrays].

We have developed a method performed on an oligoneucleotide array for genotyping HLA DRB1. The routine method Phenol-chloroform was used to extract genome DNA of standard samples. A pair of sense and antisense primers were designed according to the sequence of DRB1 exon2, then the primers and the Cy5-dCTP were used in the following PCR, thus the PCR products were labelled with Cy5. Many genotyping probes which were immobilized on the DNA Microarray made by APS-PDC method were designed. The labelled PCR products were hybridized with them, the signals were sanned by sanner and analyzed by Imagene software. We have genotyped 33 standard samples which have 12 DRB1 subtypes. The experimental results showed that the arrays we made and the method we used are accurate and sensitive. This proved that the DNA Microarray technique is good for DRB1 genotyping. Compared with PCR-SSP and PCR-SSO methods, the genotyping chip method is more intuitionistic and has the advantage of integration.

Genotype↗
PubMed2001

Inhibitory effect of recombinant TGFalpha-PE40 on neointimal proliferation after arterial balloon injury.

AIM: To investigate inhibitory effects of recombinant transforming growth factor alpha-Pseudomonas exotoxin 40 fusion protein (TGFalpha-PE40; TP40) on neointimal proliferation after arterial balloon injury. METHODS: Forty male rabbits fed a cholesterol rich diet were randomly divided into TP40 15 microg, 30 microg, 60 microg, physiologic saline control, and normal artery groups (n=8). Rabbits in the treatment groups were treated by local administration of TP40 (15 microg, 30 microg, and 60 microg per rabbit) 24 h postinjury, and those in the control group were treated by physiologic saline 24 h postinjury. Remained 8 rabbits in normal artery group were treated by TP40 (60 microg). Optical microscope, electron microscope, and computer image analysis were used to study arterial segments 2 weeks after treatment. RESULTS: Irregular thickening of the arterial intima, large amounts of smooth muscle cells (SMC) within the neointima, and stenosis of the arterial cavity were observed in the physiologic saline control group. Great inhibition of intimal proliferation and prevention of stenosis of the arterial cavity were observed in the TP40 treated groups that were examined 2 weeks postinjury by optical microscope. The uninjured carotids were histologically normal. Lots of destructural and necrotic SMC were observed in media in TP40 60 microg group by electron microscope. Computer image analysis showed that the neointimal area of the TP40-treated groups was markedly smaller than that of the saline control group (P < 0.01). CONCLUSION: Recombinant TP40 greatly inhibited neointimal proliferation after arterial balloon injury.

Angioplasty, Balloon, Coronary↗
PubMed2001

[Studies on the activity and immunohistochemistry of heme oxygenase in Schistosoma japonicum].

OBJECTIVE: To explore the activity of heme oxygenase and immunolocate the enzyme in the adult worms of Schistosoma japonicum. METHODS: Microsomal protein was isolated from the homogenate of adult S. japonicum, heme degradation and effect of different pH conditions and buffers on degrading reaction were investigated by incubating microsomal protein with hemin. The slices of whole worm and cells of S. japonicum were prepared, distribution of HO in schistosome was studied by immunofluorescent and alkaline phosphatase(AP)-immunocytochemical assays. RESULTS: Microsomal protein of adult worms can degrade the heme in vitro, the activity being 56.7 nmol bilirubin/(mg.min). The optimal pH was 8.7. Immunofluorescent and AP-immunocytochemical assays revealed that the HO distributed dispersively in the worm, and located in cytoplasm. CONCLUSION: The presence of HO was firstly proved in S. japonicum.

Animals↗
PubMed2000

Biogenetic syntheses of kopsijasminilam and deoxykopsijasminilam.

The hexacyclic ketoester 7, derived from cyclization of racemic minovincine (6), was reduced to two C-19 epimeric alcohols 8 and 9. Stereoelectronically controlled fragmentations of corresponding O-sulfonyl derivatives provided, respectively, the hexacyclic enamine 14 and, after oxidation of the olefin 16, the pentacyclic lactam 17 with a brigehead double bond. Formation of a carbamate, introduction of a second double bond at C-16, and conjugate reductive hydroxylation at C-20, or hydrogenation, gave the title products.

Alkaloids↗
PubMed2000

Compensatory projection of primary nociceptors and c-fos induction in the spinal dorsal horn following neonatal sciatic nerve lesion.

The sciatic nerve was cut in newborn rats, and prevented from regenerating for 8 weeks. The number of dorsal root ganglion (DRG) neurons in L4 and L5, the distribution of central axon terminals of primary nociceptors, and the activity of secondary nociceptors were examined in the lumbar dorsal horn. The neonatal sciatic lesion caused about 60% reduction of DRG neurons. The central terminal field of the sciatic primary nociceptors negatively labeled by in situ binding of Bandeiraea simplicifolia isolectin B4 (BsIB4) markedly shriveled. Instead, the central representation of the saphenous nerve and the posterior cutaneous nerve of the thigh (PC) expanded. The laminae I/II neuropil in the medialmost (1/4) of the L3 dorsal horn and in the second lateral (1/4) around the L4/5 junction was occupied by the BsIB4 binding sites derived from the saphenous and the PC primary neurons, respectively. Noxious stimuli applied to the receptive fields of the saphenous and the PC nerves induced c-Fos-like immunoreactivity in many neurons in the expanded central terminal fields of the nerves. The collateral sprouts of uninjured primary nociceptors did not only invade the deafferented area of the dorsal horn but also established functional synaptic connections.

Afferent Pathways↗
PubMed2000

Effect of anoxic preconditioning on ATP-sensitive potassium channels in guinea-pig ventricular myocytes.

Ischemic or hypoxic preconditioning in experimental animals and humans is described. The mechanism of preconditioning may involve several endogenous substances released from ischemic or hypoxic tissues (such as adenosine, noradrenaline and bradykinin) that stimulate protein kinase C (PKC), which then phosphorylates ATP-sensitive potassium channels (K(ATP) channels). However, the effect of hypoxic preconditioning on K(ATP) channels in guinea-pig ventricular myocytes is unclear. The uncoupler carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) has been shown to activate K(ATP) channels in isolated cardiac cells. In the present study we tested whether anoxic preconditioning (APC) could affect the opening of K(ATP) channels activated by metabolic inhibition (MI) induced by FCCP in cell-attached and inside-out patches from guinea-pig ventricular myocytes. We measured the channel activity as NP(o)i and calculated it using the formula Po=I/(Ni), where Po is open-state probability, I is the mean patch current carried by all K(ATP) channels activated in a particular patch for a certain period of time, N is the number of functioning channels in the patch, and i is the unitary current of the K(ATP) channels. In cell-attached membrane patches, after about 5 min of initiating MI, K(ATP) channels were activated at a holding potential of +40 mV (NP(o)i=3.70+/-0.9 pA); APC pretreatment (3 min of anoxia followed by 7 min of reoxygenation) before MI (APC+MI group) shortened the time to activate K(ATP) channels by MI (2.3+/-0.5 min) and increased the activity of K(ATP)currents (NP(o)i=8.4+/-0.5 pA). This effect of APC was eliminated by administration of a PKC blocker, chelerythrine (5 microM), for 5 min before the APC pretreatment. In the inside-out patches, the IC50 of intracellular ATP against the K(ATP) channels in the APC+MI group was significantly increased to 642 microM compared to that in the MI group (IC50 of intracellular ATP =252 microM). Chelerythrine inhibited the effect of APC on the sensitivity of K(ATP) channels to the intracellular ATP concentration (IC50 of [ATP]i=301 microM). Our results demonstrate that APC can increase and accelerate the opening of K(ATP) channels induced by MI, and decrease the sensitivity of K(ATP) channels to [ATP]i, which is mediated by promoting the activation of PKC induced by APC.

Adenosine Triphosphate↗
PubMed2000

IgG anti-melanocyte antibodies purified from patients with active vitiligo induce HLA-DR and intercellular adhesion molecule-1 expression and an increase in interleukin-8 release by melanocytes.

An immunologic hypothesis is currently proposed as a possible pathogenesis of nonsegmental-type vitiligo. IgG antibodies against melanocyte surface antigens exist in the serum of patients with vitiligo vulgaris. IgG anti-melanocyte antibodies were reported to induce melanocyte damage in vitro by a complement-mediated mechanism and antibody-dependent cellular cytotoxicity. Perilesional melanocytes express major histocompatibility complex class II antigens and a higher intercellular adhesion molecule-1 compared with those in normal skin. The purpose of this study was to determine the role of IgG anti-melanocyte antibodies in the inappropriate expression of major histocompatibility complex class II antigens and intercellular adhesion molecule-1 on melanocytes. IgG anti-melanocyte antibody samples were purified from the individual serum of patients with active vitiligo. After incubation of IgG anti-melanocyte antibodies with cultured melanocytes, the results revealed: (i) IgG anti-melanocyte antibody stimulated HLA-DR expression on melanocytes; (ii) intercellular adhesion molecule-1 expression on melanocytes was significantly induced by IgG anti-melanocyte antibodies; and (iii) IgG anti-melanocyte antibodies induced an increase in interleukin-8 release from melanocytes. The major histocompatibility complex class II molecules expressed in melanocytes can present antigens to CD4 helper cells as antigen-presenting cells and elicit an immune response. Intercellular adhesion molecule-1 is an important adhesion molecule involved in leukocyte and parenchymal cell interaction and thus plays an essential part in immunologic and inflammatory reactions. It is reasonable to speculate that abnormal expressions of HLA-DR and intercellular adhesion molecule-1 on melanocytes by IgG anti-melanocyte antibodies would present vitiligo antigens and allow the antigen-specific immune effector cell attack that results in melanocytotoxicity.

Antibodies, Anti-Idiotypic↗
PubMed2000

GSTT1 and GSTM1 null genotypes and the risk of gastric cancer: a case-control study in a Chinese population.

Glutathione S-transferase (GST) enzymes are involved in detoxification of many potentially carcinogenic compounds. The homozygous deletions or null genotypes of GSTT1 (theta class) and GSTM1 (mu class) genes may be associated with an increased risk of cancer. Few studies have evaluated the relationship between GSTT1, GSTM1 and the risk of gastric cancer, as well as the potential interactions between these genetic markers and other risk factors of gastric cancer in the Chinese population. We conducted a case-control study with 143 cases with gastric cancer, 166 chronic gastritis (CG) cases and 433 cancer-free population controls from Yangzhong County, China. The epidemiological data were collected by a standard questionnaire for all of the subjects, and blood samples were obtained from 91 gastric cancer cases, 146 CG cases, and 429 controls. GSTT1 and GSTM1 genotypes were assayed by the PCR method, and Helicobacter pylori infection was measured by the ELISA method. Using logistic regression model in SAS, we assessed the independent effects of GSTT1 and GSTM1 null genotypes on the risk of gastric cancer and their potential interactions with other factors. The prevalence of GSTM1 null genotype was 48% in gastric cancer cases, 60% in CG patients, and 51% in controls. The prevalence of GSTT1 null genotype was 54% in gastric cancer cases, 48% in CG patients, and 46% in controls. After controlling for age, gender, education, pack-years of smoking, alcohol drinking, body mass index, H. pylori infection, and fruit and salt intake, the adjusted odds ratio (OR) for GSTT1 and gastric cancer was 2.50 (95% confidence interval (CI), 1.01-6.22). When gastric cancer cases were compared with CG patients, the adjusted OR for GSTT1 was 2.33 (95% CI, 0.75-7.25). However, GSTT1 null genotype was not associated with the risk of CG when using population controls. No obvious association was found between GSTM1 and the risk of both gastric cancer and CG. Our results suggest that GSTT1 null genotype may be associated with an increased risk of gastric cancer in a Chinese population.

Adult↗
PubMed2000

Studying the growth of cervical carcinoma nests and angiogenesis by immunostaining, quantitation and three-dimensional structural analysis.

OBJECTIVE: To analyze the relationship and mutual effect of the growth of cervical carcinoma nests and angiogenesis. STUDY DESIGN: Serial paraffin sections of cervical squamous carcinoma were stained in repeated order with hematoxylin-eosin (HE), immunostain for factor VIII-related antigen, type IV collagen and proliferating cell nuclear antigen (PCNA). Three-dimensional reconstructions were made, and the volumes of carcinoma nests, necrosis and microvessels were measured. RESULTS: Two types of cervical carcinoma nests were distinguished on the basis of their growth characteristics and vascularity (groups I and II). Group I nests: The carcinoma cells were proliferating actively, as determined by their morphology and PCNA staining. There were abundant microvessels. Some endothelial sprouts and cords penetrated the nests and then formed networks and new vessels. The volume ratio of microvessels, including sprouts and cords, to the nests was 0.6282:1. Group II nests: The center of these nests underwent necrosis. The peripheral cells were rather small, with no mitosis. The PCNA index was rather low; these nests grew very slowly. There were only a few surrounding microvessels with no endothelial sprouts or cords. The volume ratio of vessels to nest was 0.0657:1. CONCLUSION: Two types of cervical carcinoma nests show a close relationship and mutual effect of the growth of carcinoma nest and angiogenesis. Group I nests grow and develop well, with abundant microvessels. Thus, many tumor cells may be angiogenic and induce angiogenesis; growth of the nests seemed dependent on adequate neovascularization. Group II nests grow slowly, with a few microvessels; the center of the nests undergoes necrosis. The inadequate blood supply must be one of the important causes of necrosis. Considering that there must have been abundant neovascularization during their growth in the past, most of the microvessels must have been obliterated and then reabsorbed to make the remaining vessels so few.

Cell Nucleus↗
PubMed2000

Antisense IRAK-2 oligodeoxynucleotide inhibits interleukin-1-induced nuclear factor-kappa B activation in vitro.

AIM: To study the inhibitory effects of antisense interleukin-1 receptor associated kinase-2 (IRAK-2) oligodeoxynucleotide (ODN) on interleukin-1 (IL-1)-stimulated nuclear factor-kappa B (NF-kappa B) activation. METHODS: Antisense IRAK-2 ODN was delivered by lipofectin encapsulation into human embryonic kidney 293 cells (HEK 293 cells). The levels of NF-kappa B were assayed by sandwich ELISA. RESULTS: (1) Treatment of HEK 293 cells with IL-1 enhanced NF-kappa B level in nuclei by 518.5% +/- 2.1%. (2) Antisense IRAK-2 ODN inhibited IL-1-induced NF-kappa B activation in a concentration (1-8 micrograms)- and time (5-24 h)-dependent manner. A maximum inhibition was 70.7% +/- 1.0% from Acontrol 0.834 +/- 0.014 to 0.244 +/- 0.008 after treatment with antisense IRAK-2 ODN 4 micrograms for 8 h. CONCLUSION: Antisense IRAK-2 ODN inhibited IL-1-induced NF-kappa B activation.

Cells, Cultured↗
PubMed2000

Effects of antisense IRAK-2 oligonucleotides on PGI2 release induced by IL-1 and TNF.

AIM: To explore the effects of antisense interleukin-1 receptor associated kinase-2 oligonucleotide (IRAK-2 ODN) on the prostacyclin (PGI2) synthesis in human umbilical vein endothelial cells (HUVEC) induced by interleukin-1 (IL-1) and tumor necrosis factor (TNF). METHODS: The HUVEC were transfected with antisense IRAK-2 ODN and stimulated with IL-1 and TNF. The levels of PGI2 release were analyzed by competitive ELISA. RESULTS: Pre-transfection with antisense IRAK-2 ODN could remarkably decrease the levels of PGI2 synthesis induced by IL-1 in a time- and concentration-dependent manner, whereas it could not attenuate the one stimulated by TNF. CONCLUSION: The responses of antisense IRAK-2 ODN to IL-1 and TNF-stimulated PGI2 release are different. IRAK-2 plays a key role in the IL-1 signaling events leading to PGI2 release.

6-Ketoprostaglandin F1 alpha↗
PubMed2000

[Studies on apoptosis and its induction in Schistosoma japonicum].

OBJECTIVE: To explore the apoptosis and its induction in S. japonicum. METHODS: The eggs and adult cells of S. japonicum were isolated. The adult cells were incubated with H2O2, dexamethasone and cyclosporin A, cyclosporin A vehicle solution, respectively in order to initiate the apoptosis. The eggs were treatd at 4 degrees C, 37 degrees C and 42 degrees C, respectively for induction of apoptosis. The occurrence of apoptosis was supervised by agarose gel electrophoresis and in situ end labelling. RESULTS: DNA ladder-band characteristic of apoptosis appeared in the cells of adult worms after incubated with H2O2, dexamethasone or cyclosporin A and the eggs treated at 42 degrees C, whereas no DNA ladder band was found in other control groups. In situ end labeling revealed that the positive fluorescence could be seen in the cells incubated with H2O2, dexamethasone or cyclosporin A and few nuclei in the control group and cyclosporin A vehicle solution group appeared positive fluorescence. CONCLUSION: Apoptosis in the cells of S. japonicum adults and eggs induced by chemical or physical agents was observed.

Animals↗
PubMed1999

Regulatory role of extracellular matrix components in expression of matrix metalloproteinases in cultured hepatic stellate cells.

Hepatic stellate cells (HSCs) were changed in their morphology, proliferative activity, and functions by culturing on type I collagen gel, as compared to the culture on polystyrene surface. HSCs have been found to produce extracellular matrix components and matrix metalloproteinases (MMPs). In this study, we have assessed the effects of several types of substrata on the expression of MMPs in HSC culture. MMP-1 expression was detectable in HSC culture on polystyrene surface and on type I collagen gel by immunofluorescence staining and reverse transcriptase-polymerase chain reaction (RT-PCR). The results from in situ zymography revealed the presence of interstitial collagenase activity around HSCs and along their cellular processes. Although proMMP-2 and proMMP-9 were detectable by gelatin zymography in the conditioned medium from both cultures using type I collagen gel and Matrigel as substratum, an active form of MMP-2 but not of MMP-9 was detected only in the culture using type I collagen as a substratum. Tissue inhibitor of metalloproteinase-2 expression was observed by RT-PCR in HSCs cultured on or in type I collagen gel, suggesting the suppression of MMP-2 activity detected in HSC culture using type I collagen. These results indicate a differential expression of MMP activity, hence the remodeling of extracellular matrix components is dependent on the substratum used for HSC culture. The HSC culture using several types of substrata appears to be a useful in vitro model to study the mechanism of extracellular matrix remodeling.

Actins↗