Biomedical subjects

Y Kuang

Publications and source records attributed to Y Kuang.

At least 37 records · Page 2Linked to original sources

PubMed2000

An analysis of two polymorphic points of the 7th intron of human p53 gene.

OBJECTIVE: To detect polymorphic points of the 7th intron of human p53 oncogene. METHODS: Polymerase chain reaction (PCR) and double- strand DNA direct sequencing were used to analyse sequence alteration of p53 intron 7. One hundred and five cases of normal human peripheral blood samples with no genetic relation were investigated. RESULTS: There were two polymorphic points in the 7th intron of p53 gene. The first one was localized at 73 base pair (bp) to 3'-end of exon 7; the other one at 93. Three genotypes were found. Twenty-two cases were of type TG, 37 cases were of type CT, and the other 46 cases were of heterozygote. Because the first point was alteration of GGGCCC to GGGTCC or its heterozygote, it had a point alteration of enzyme Apa I. CONCLUSION: There are two polymorphic points in the 7th intron of human p53 gene, which may be of importance to identification of individual genetic relation and to judging of a case in forensic medicine.

Genes, p53↗

PubMed2000

[Effects of ischemic preconditioning on apoptosis of hepatocytes in liver transplantation in rats].

OBJECTIVE: To evaluate the effects of ischemic preconditioning (IP) on hepatocyte apoptosis in ischemia/reperfusion injury of grafted liver and clarify its mechanism. METHODS: Orthotopic liver transplantation with cuff anastomosing method for the portal vein, suprahepatic vena cava and infrahepatic vena cava in the rats were divided into two groups: with and without IP treatment. The parameters of liver function were determined by auto-biochemical analyser. The concentrations of malondialdehyde (MDA) were measured with chromometry. The apoptotic hepatocytes in grafts liver were detected by flow cytometry combined with the in situ terminal deoxynucleotidyl transferase-mediated dUTP-FITC nick end-labeling (TUNEL) method. RESULTS: The levels of AST, ALT, LDH in the serum, and MDA and apoptotic cells in the liver were significantly increased compared with normal values after ischemia/reperfusion to the grafted liver. After IP treatment, the levels of AST, ALT, LDH, MDA and apoptotic cells were significantly decreased. CONCLUSION: IP can attenuate ischemia/reperfusion injury by alleviating lipid peroxide and decreasing apoptosis of hepatocytes.

Animals↗

PubMed2000

1376G-->T mutation of G6PD gene in Han and Li nationalities in Hainan, China.

OBJECTIVE: To investigate the 1376G-->T mutation of G6PD gene in the cases of G6PD deficiency in the Han nationality and the Li nationality of Hainan, China. METHODS: DNAs were extracted from the white blood cells of G6PD deficient cases by salt-out method. Allelic specific polymerase chain reaction was used to detect the 1376G-->T mutation. RESULTS: Fifty-nine Han nationality cases and 32 Li nationality cases were analysed; the 1376G-->T mutation was found in 19 Han cases(32.2%) and 18 Li cases(56.2%). CONCLUSION: 1376G-->T is a common mutation which causes G6PD deficiency in the Han nationality and the Li nationality in Hainan, China. Based on the phylogenetic tree of populations in China, these results indicate that the mutation might occur prior to the divergence of the Han and Li nationalities. It is of significance to study the mutations of G6PD gene in different nationalities in China for elucidating the origin, migration and evolution of the nationalities.

Biological Evolution↗

PubMed2000

Changes in systemic and splanchnic hemodynamics after orthotopic liver transplantation in cirrhotic rats.

OBJECTIVE: To investigate early changes in systemic and splanchnic hemodynamics after orthotopic liver transplantation (OLT) in normal and cirrhotic rats. METHODS: Male Sprague-Dawley rats were divided into 4 groups: normal controls (NL, n = 10), intrahepatic portal hypertension (IHPH, n = 10) induced by injection of CCl4, normal rats with OLT (NL-OLT, n = 9) and IHPH rats with OLT (IHPH-OLT, n = 16). IHPH-OLT rats were divided into 2 subgroups: 3 days (Group A, n = 9) and 7 days (Group B, n = 7) after OLT. OLT was performed in rats using cuffs for the anastomosis of the suprahepatic inferior vena cava, infrahepatic vena cava and portal vein. Two weeks after production of IHPH rats, 7 days after NL-OLT rats, 3 days and 7 days after IHPH-OLT rats, radioactive microspheres were used in a hemodynamic study. RESULTS: There were no significant differences in hemodynamic changes between NL-OLT and NL rats, except mean arterial blood pressure (MAP). The characteristics of systemic and splanchnic hyperdynamic circulatory state, including increased cardiac output and splanchnic blood flow, decreased mean arterial blood pressure, total peripheral vascular resistance and splanchnic vascular resistance were observed in IHPH, IHPH-OLT A, and IHPH-OLT B rats. The magnitude of hyperhemodynamics was in the order of IHPH > IHPH-OLT A > IHPH-OLT B rats. Moreover, the derangement of splanchnic hyperhemodynamics was more significant than that of systemic hyperthermodynamics. CONCLUSIONS: The present study demonstrates that the persistence of early systemic and splanchnic hyperkinetic circulation after OLT may be the consequence of factors which maintain hyperhemodynamics in liver cirrhosis, where portal hypertension is not completely eliminated. Hyperhemodynamics is not induced by OLT per se.

Animals↗

PubMed1999

Boo, a novel negative regulator of cell death, interacts with Apaf-1.

In this report, we describe the cloning and characterization of Boo, a novel anti-apoptotic member of the Bcl-2 family. The expression of Boo was highly restricted to the ovary and epididymis implicating it in the control of ovarian atresia and sperm maturation. Boo contains the conserved BH1 and BH2 domains, but lacks the BH3 motif. Like Bcl-2, Boo possesses a hydrophobic C-terminus and localizes to intracellular membranes. Boo also has an N-terminal region with strong homology to the BH4 domain found to be important for the function of some anti-apoptotic Bcl-2 homologues. Chromosomal localization analysis assigned Boo to murine chromosome 9 at band d9. Boo inhibits apoptosis, homodimerizes or heterodimerizes with some death-promoting and -suppressing Bcl-2 family members. More importantly, Boo interacts with Apaf-1 and forms a multimeric protein complex with Apaf-1 and caspase-9. Bak and Bik, two pro-apoptotic homologues disrupt the association of Boo and Apaf-1. Furthermore, Boo binds to three distinct regions of Apaf-1. These results demonstrate the evolutionarily conserved nature of the mechanisms of apoptosis. Like Ced-9, the mammalian homologues Boo and Bcl-xL interact with the human counterpart of Ced-4, Apaf-1, and thereby regulate apoptosis.

Amino Acid Sequence↗

PubMed1999

Vanilloid receptor agonists potentiate the in vivo local anesthetic activity of percutaneously injected site 1 sodium channel blockers.

BACKGROUND: Capsaicin, the pungent ingredient in chili peppers, is a vanilloid with noxious and analgesic effects that inhibits tetrodotoxin-resistant sodium currents. Because tetrodotoxin-resistant currents are found primarily in small-diameter nociceptor afferents of the peripheral nerves, their inhibition may lead to selective analgesia. Therefore, the authors evaluated the interactions between tetrodotoxin, a site 1 sodium channel blocker, and capsaicin on nerve blockade in vivo. METHODS: Percutaneous sciatic nerve injections with 0 to 9.9 mM capsaicin, 0 to 120 microM tetrodotoxin, or both were administered to male Sprague-Dawley rats. Thermal nociceptive and motor blockade were measured. Data were expressed as medians with 25th and 75th percentiles. RESULTS: Capsaicin produced a transient increase in thermal latency with no effect on motor strength. Tetrodotoxin reduced motor strength for a longer duration than nociception. The interaction between tetrodotoxin and capsaicin was synergistic, as evidenced by (1) supraadditive prolongation of both nociceptive and motor block, with the effect of capsaicin reversed by the vanilloid antagonist capsazepine, and (2) synergism in the frequency that rats achieved maximal block shown by isobolographic analysis. The combination of tetrodotoxin and capsaicin showed less motor predominance than tetrodotoxin did alone. Similar interactions were found between tetrodotoxin and resiniferatoxin (another vanilloid), and between capsaicin and saxitoxin (another site 1 sodium channel blocker), but much less so between bupivacaine and capsaicin. CONCLUSIONS: Site 1 sodium channel blockers and vanilloids have synergistic effects on nerve blockade in vivo. These interactions may be useful in developing prolonged local anesthetics and elucidating mechanisms of functionally selective nerve blockade.

Anesthetics, Local↗

PubMed1999

The molecular and cellular biology of Fanconi anemia.

Fanconi anemia is a rare autosomal recessive disease characterized by multiple congenital abnormalities, bone marrow failure, and cancer susceptibility. The mean age of onset of anemia is 8 years, and the mean survival is 16 years. Death usually results from complications of bone marrow failure. Considerable progress in Fanconi anemia research has resulted from the recent identification and cloning of three Fanconi anemia genes. The current review describes the structure and function of the Fanconi anemia genes and describes the role of the encoded Fanconi anemia proteins in a cellular pathway controlling chromosome stability.

Animals↗

PubMed1999

Fanconi anemia proteins FANCA, FANCC, and FANCG/XRCC9 interact in a functional nuclear complex.

Fanconi anemia (FA) is an autosomal recessive cancer susceptibility syndrome with at least eight complementation groups (A to H). Three FA genes, corresponding to complementation groups A, C, and G, have been cloned, but their cellular function remains unknown. We have previously demonstrated that the FANCA and FANCC proteins interact and form a nuclear complex in normal cells, suggesting that the proteins cooperate in a nuclear function. In this report, we demonstrate that the recently cloned FANCG/XRCC9 protein is required for binding of the FANCA and FANCC proteins. Moreover, the FANCG protein is a component of a nuclear protein complex containing FANCA and FANCC. The amino-terminal region of the FANCA protein is required for FANCG binding, FANCC binding, nuclear localization, and functional activity of the complex. Our results demonstrate that the three cloned FA proteins cooperate in a large multisubunit complex. Disruption of this complex results in the specific cellular and clinical phenotype common to most FA complementation groups.

Animals↗

PubMed1999

Effects of nitric oxide inhibitor on prostacyclin biosynthesis in portal hypertensive rats.

OBJECTIVE: To evaluate the effects of nitric oxide inhibitor on prostacyclin (PGI2) biosynthesis and the role of PGI2 in hyperhemodynamics of portal hypertension. METHODS: Sprague Dawley rats were divided into four groups: intrahepatic portal hypertension (IHPH) by injection of CCl4, prehepatic portal hypertension (PHPH) by stenosis of the portal vein, end-to-side portacaval shunt (PCS), and sham-operated controls (SO). Animals of each group were subdivided into 2 groups: systemic administration of nitric oxide inhibitor L-NMMA and vehicle. The radioactive microsphere method was used for hemodynamic study. The level of plasma PGI2 (6-keto-PGF1 alpha) was measured by radioimmunoassay. RESULTS: The characteristics of hyperdynamic circulatory state including increased cardiac output and splanchnic blood flow, decreased mean arterial blood pressure, total peripheral vascular resistance, and splanchnic vascular resistance were observed in IHPH, PHPH and PCS rats. The magnitude of hyperhemodynamics was in the order of PCS > PHPH > IHPH rats. The hyperdynamic circulatory state in IHPH, PHPH and PCS rats could be effectively reversed by L-NMMA to the baseline values of hemodynamics in SO rats. The baseline concentrations of plasma 6-keto-PGF1 alpha (ng/ml) in PHPH, IHPH, PCS, and SO rats were 6.93 +/- 2.43, 5.09 +/- 2.27, 2.36 +/- 1.01 and 1.56 +/- 0.61, respectively. The concentrations of plasma 6-Keto-PGF1 alpha in PHPH, IHPH and PCS rats were significantly higher than those in SO rats. Moreover, the concentrations were significantly higher in PHPH and IHPH rats than in PCS rats (P < 0.05). After administration of L-NMMA, the concentrations of plasma 6-Keto-PGF1 alpha (ng/ml) in PHPH, IHPH, PCS and SO rats were 7.69 +/- 2.98, 5.68 +/- 2.66, 5.50 +/- 0.79, 5.02 +/- 2.86, respectively. As compared to the baseline value, the concentrations of 6-keto-PGF1 alpha rats were slightly increased in IHPH, PHPH rats (P > 0.05), but significantly increased in PCS and SO rats (P < 0.05). CONCLUSIONS: In this study, the hyperdynamic circulatory state in portal hypertensive rats and portacaval shunt rats was completely reversed by L-NNMA to normal, but the level of 6-keto-PGF1 alpha was still elevated. The results indicate that PGI2 is not involved in hyperhemodynamics of portal hypertension.

6-Ketoprostaglandin F1 alpha↗

PubMed1999

[Clinical study of metastasis of thoracic lymph node in resectable lung cancer].

OBJECTIVE: To study the metastatic pattern of thoracic lymph node in resectable lung cancer. METHODS: From January 1992 to July 1998, the lymph nodes in hilar(N1) and mediastinal(N2) were resected based on their distribution in 160 patiens with resectable lung cancer and were examined by pathology. Number, size and colour of lymph nodes in each regions were recorded. Each lymph node was examined by routine pathology and immunohistochemistry. Quantity of metastatic lymph node was reported according to their regions. RESULTS: 99 cases(61.9%) had thoracic lymph nodes metastasis and 73 cases (45.6%) had mediastinal lymph nodes metastasis. Of those, only N1 metastasis was 16.3%, from N1 to N2 metastasis was 32.5%, only N2 metastasis was 13.1%. The metastatic frequencies in 11, 10, 7, 5 and 4 regions around the hilar or root of lung were 30.0%, 27.5%, 16.9%, 28.8% and 20.0%, respectively. Those were higher than 9, 6, 3, 2 and 1 regions far from the root of lung. The metastatic rate of lymph node in 2.0 cm or greater, 1.0 cm or greater and less than 1.0 cm was 60.7%, 15.5% and 4.3%, respectively (P < 0.001). The smallest metastatic lymph node was only 0.2 cm x 0.2 cm. Statistical analysis revealed that metastatic rate of thoracic lymph nodes was not relevant to different area, size and course of tumors. CONCLUSIONS: The lymph nodes metastases of most cases were spreading from the near to the distant, from lower to upper, through the hilar to the mediastinal. Lymph nodes metastases occurred easier in SCLC than in NSCLC (P < 0.05). It must be depended on pathologic examination to confirm whether or not the tumor has metastasis to lymph node.

Female↗

PubMed1999

[Cytological diagnosis of Hashimoto's hyperthyroidism].

OBJECTIVE: To assess the value of thyroid fine needle biopsy (FNB) in Hashimoto's hyperthyroidism. METHODS: FNB for was performed 58 (5 males and 53 females, aged from 13 to 66 years) of 1 031 patients who was performed clinically dignosised as having hyperthyroidism according to clinic symptoms, the results of physical and, laboratory examination, especially the increased the serum circle antibody and lowered sTSH during March 1995 to February 1998. Their smears were classified into 4 types according to the degree of degeneration of adenoidal cell and lymphocyte invasion. RESULTS: Hyperthyroidism was observed in 5 cases, I type in 9, II type in 9, III type in 4, and IV type in 31 (53%). CONCLUSIONS: FNB is helpful in diagnosis of hyperthyroidism.

Adolescent↗

PubMed1998

The role for endothelin in mesangial proliferative glomerulonephritis.

To understand the effect of endothelin (ET) on the mesangium and matrix proliferation on the basis of hyperlipidemia, the model of mesangial proliferative glomerulonephritis (MSPGN) was established by intravenously giving calf serum albumin (250 mg/L) to the rabbits fed on feed containing 1% cholesterol for 4-8 weeks. Our results showed that in the 4th week of the experiment, the ET level in experiment group was significantly higher than that of normal controls (P < 0.01) and the pathological examination revealed development of MSPGN. In the 8th week of the experiment, the ET level was further elevated and pathological study demonstrated local glomerular sclerosis and infiltration of lymphocytes of interstitia. We are led to conclude that ET, as a newly identified hormone, is involved in the pathogenesis and development of MSPGN and acts as an important regulator in the proliferation of mesangium and accumulation of matrix of basal membrane.

Animals↗

PubMed1998

Modeling and analysis of a marine bacteriophage infection.

A mathematical model for the marine bacteriophage infection is proposed and its essential mathematical features are analyzed. Since bacteriophage infection induces bacterial lysis which releases into the marine environment, on the average, 'b' viruses per cell, the parameter b epsilon (1, t infinity) or 'virus replication factor' is chosen as the main parameter on which the dynamics of the infection depends. We proved that a threshold b* exists beyond which the endemic equilibrium bifurcates from the free disease one. Still, for increasing b values the endemic equilibrium bifurcates toward a periodic solution. We proved that a compact attractor set omega within the positive cone exists and within omega the free disease equilibrium is globally stable whenever b < or = b*, whereas it becomes a strong uniform repeller for b > b*. A concluding discussion with numerical simulation is then presented.

Bacteria↗

PubMed1998

[Experimental study of the effect on growth of Schwann cell from chitin and chitosan in vitro].

In order to study the effect of chitin and chitosan on the growth of Schwann cell (SC) of rats in vitro, the SC was isolated from sciatic nerve and brachial plexus of new-born rats. After the enzymatic and mechanical dissociation, the cell suspension was vaccinated on chitin membrane and chitosan fluid-coated glass coverslips. Then, the growth of SC was examined at 1, 3, 7 days after culture under light microscope and scanning electron microscope. The results showed that 94 percent of the cell grown from was SC and only 6% was fibroblast (FB), while that of the control SC 71% and FB 29% in population. The number of SC in chitosan suspension was more than that in chitin. Therefore, the conclusion was that the chitin and chitosan was histocompatible to SC, and chitosan suspension was superior to chitin, and both could inhibit the growth of fibroblast.

Animals↗

PubMed1998

[Interleukin-6 and its soluble receptors in human breast cancer].

OBJECTIVE: To study interleukin-6(IL-6) and its receptors in human breast cancer. METHODS: Using ELISA method and ABC immunohistochemistry, IL-6 and its receptors were examined in 45 cases of breast cancer, 10 cases of benign breast diseases and 17 cases of healthy women. RESULTS: High levels of serum IL-6 and its soluble receptors were frequently observed in breast cancer patients. The levels correlated with the stage and axillary lymph node involvement. The positive staining of IL-6, IL-6R alpha, gp130 were 68.9% in neoplasm tissue. CONCLUSION: IL-6 and its soluble receptors may be important paramenters reflecting the biological behaviour and prognosis of breast cancer.

Breast Neoplasms↗

PubMed1998

Mechanism of overproduction of plasma prostacyclin in portal hypertensive rats.

OBJECTIVE: To evaluate the role of increased portal pressure and portosystemic shunting in elevated level of prostacyclin (PGI2) in portal hypertension. METHODS: Thirty-six male Sprague-Dawley rats were divided into four groups: prehepatic portal hypertension (PHPH, 8 rats), intrahepatic portal hypertension (IHPH, 9), end-to-side portacaval shunt (PCS, 8), and sham-operated controls (SO, 11). Two weeks after surgery, free portal pressure (FPP) was measured; systemic and splanchnic hemodynamics was studied by radioactive microsphere technique and blood sample from the femoral artery was obtained to measure the level of plasma 6-keto-PGF1 alpha with radioimmunoassay. RESULTS: The FPP (mmHg) in IHPH, PHPH, PCS and SO rats was 13.10 +/- 1.02, 12.10 +/- 1.52, 3.0 +/- 0.82 and 6.86 +/- 0.69, respectively. The value of FPP was significantly increased in IHPH, PHPH rats and significantly decreased in PCS rats when compared to SO rats. Cardiac index (CI) and portal venous inflow (PVI) were in the order of PCS > PHPH > IHPH > SO rats. Portosystemic shunting (PSS) in PCS, PHPH, IHPH was 99.7 +/- 0.29%, 76.02 +/- 20.62% and 30.34 +/- 10.18%, respectively. The concentrations of plasma 6-keto-PGF1 alpha (ng/ml) in PHPH, IHPH, PCS and SO rats were 6.93 +/- 2.43, 5.09 +/- 2.27, 2.36 +/- 1.01 and 1.56 +/- 0.61, respectively. The concentrations of plasma PGI2 in PHPH, IHPH and PCS rats were significantly higher than those in SO rats. Furthermore, the concentrations of plasma PGI2 in PHPH and IHPH rats were also significantly higher than those in PCS rats. Moreover, a closed positive correlation existed between plasma PGI2 and FPP (r = 0.67, P < 0.001). CONCLUSIONS: The results of the present study suggest that the elevated PGI2 in portal hypertension is mainly due to the overproduction of PGI2 in vascular epithelium cells induced by increased portal pressure, whereas portosystemic shunting and liver dysfunction play a secondary role. In addition, the results of this study do not support that PGI2 mediated the hyperhemodynamics in portal hypertension.

6-Ketoprostaglandin F1 alpha↗

PubMed1998

[The role of nitric oxide in hyperdynamic circulation in portal hypertensive rats].

OBJECTIVE: To evaluate the role of nitric oxide (NO) in hyper-hemodynamics in portal hypertension, we investigated the effects of nitric oxide synthase inhibitor L-NMMA with or without L-arginine, the substrate for enzyme NO synthase on the systemic and splanchnic hemodynamics in portal hypertensive rats. METHOD: Ninety-seven male Sprague-Dawley rats were divided into four groups: intrahepatic portal hypertension (IHPH, n = 23) by injection of CCl4, prehepatic portal hypertension (PHPH, n = 26) by stenosis of the portal vein, end-to-side portacaval shunt (PCS, n = 23), and sham-operated controls (SO, n = 25). Animals of each group were divided into three subgroups: systemic administration of L-NMMA (50 mg/kg BW, 1 ml), L-NMMA (50 mg/kg BW, 0.5 ml) plus L-arginine (30 mg/kg BW, 0.5 ml), and normal saline solution (1 ml). The radioactive microsphere method was used for hemodynamic study. RESULT: There was the characteristic of hyperdynamic circulatory state including increased cardiac output and splanchnic blood flow, decreased mean arterial blood pressure, total peripheral vascular resistance and splanchnic vascular resistance in IHPH, PHPH and PCS rats. The hyperdynamic circulatory state in IHPH, PHPH and PCS rats could be effectively reversed by L-NMMA to the resting values of hemodynamics in SO rats, but not the levels after administration of L-NMMA in SO rats, indicating that there is excessive production of NO in portal hypertensive and PCS rats. Administration of L-arginine counterbalanced the effects of L-NMMA on hyperdynamic circulatory state in portal hypertensive and PCS rats. CONCLUSION: NO is an important mediator of hyperdynamic circulation in portal hypertension.

Animals↗

PubMed1997

Roles of phospholipase C beta2 in chemoattractant-elicited responses.

The physiological roles of phospholipase C (PLC) beta2 in hematopoiesis, leukocyte function, and host defense against infection were investigated using a mouse line that lacks PLC beta2. PLC beta2 deficiency did not affect hematopoiesis, but it blocked chemoattractant-induced Ca2+ release, superoxide production, and MAC-1 up-regulation in neutrophils. In view of these effects, it was surprising that the absence of PLC beta2 enhanced chemotaxis of different leukocyte populations and sensitized the in vivo response of the PLC beta2-deficient mice to bacteria, viruses, and immune complexes. These data raise questions about the roles that PLC beta2 may play in signal transduction induced by chemoattractants in leukocytes.

Animals↗