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Biomedical subjects

Hong Zhu

Publications and source records attributed to Hong Zhu.

105 records · Page 6Linked to original sources
PubMed2002

The triazine hydrolase gene trzN from Nocardioides sp. strain C190: cloning and construction of gene-specific primers.

Using oligonucleotides derived from the N-terminal sequence of a triazine hydrolase from Nocardioides sp. strain C190, two DNA fragments containing trzN were cloned into Escherichia coli and their nucleotide sequences were determined. The 456-amino acid polypeptide predicted from the 1356-bp trzN ORF displayed significant similarity to triazine hydrolases from Pseudomonas and Rhodococcus isolates and belonged to the same amidohydrolase family. The trzN gene was flanked by two DNA sequences possessing 57 and 69% identity, respectively, at the protein level to Rhodococcus erythropolis sequences for a transposase and a transposase helper protein. Amplification primers specific to trzN were tested in soils inoculated with strain C190. The results demonstrated that the primers were specific to trzN, and could detect populations at 10(8) cfu g(-1) soil using 250-mg soil samples.

Actinomycetales↗
PubMed2002

[Comparison study on child anxiety disorder with different family characteristics]

OBJECTIVE: To investigate the relations between child anxiety disorder with different family characte ristics. METHODS Family characteristics were measured by family environment scale. 144 mothers of child with anxiety disorder and 100 mothers of health children were invited to fill out questionnaires. RESULTS There were obviously different family characteristics between health children and those with anxiety disorder except phobic anxiety disorder. The scores of cohesion, independence, achievement orientation and active recreational orientation in children with anxiety disorder were significantly lower than those in health children P<0.01). In 4 groups of children with anxiety disorder cohesion showed correlation with intellectual- cultural orientation r=0.9219, 0.8348, 0.8935, 0.9550 respectively, P<0.001). CONCLUSION: The importance of family characteristics must be emphasized for children with anxiety disorder.

Journal Article↗
PubMed2002

The intervention research on understanding of the AIDS prevention and occupational safety of the dentist in Kunming and west part of Yunnan.

OBJECTIVE: To investigate the knowledge, attitude of the AIDS prevention and occupational safety in dentist in Kunming and west part of Yunnan and evaluate the effect of education and intervention. METHOD: 165 dentists in Yunnan were tested by KABP questionnaire before education. All of the 165 dentists participated a course on AIDS prevention. After that course the same questionnaire was answered by participants. RESULT: The correct rates obviously increased. The understanding rates of the oral prevention measure were obviously improved. CONCLUSION: The knowledge of AIDS prevention is very low in dentist in Kunming and west part of Yunnan. The education intervention can effectively improve the understanding level of the AIDS prevention in dentist.

Acquired Immunodeficiency Syndrome↗
PubMed2002

[Usefulness of left ventricular opacification with intravenous contrast echocardiography in patients with asymptomatic negative T waves on electrocardiography].

OBJECTIVES: Patients with electrocardiography (ECG) abnormalities sometimes present without obvious symptoms or abnormal physical findings. In some cases, echocardiography fails to reveal abnormalities compatible with the ECG findings because of poor echocardiographic image quality. New intravenous contrast agents now enable opacification of the left ventricular cavity in the clinical setting. The usefulness of left ventricular opacification (LVO) by ultrasonic contrast agent was examined in asymptomatic patients with negative T waves on ECG. METHODS: Thirty-four consecutive patients (23 males, 11 females, mean age 68 +/- 10 years) with negative T waves without symptoms or abnormal physical findings underwent routine transthoracic echocardiography and LVO by intravenous injection of Levovist using harmonic imaging. RESULTS: Without LVO, abnormal echocardiographic findings compatible with the negative T waves were identified in 22 (65%) of the 34 patients. With LVO, the endocardial border of the left ventricle was observed in all patients and findings compatible with negative T waves were detected in 32 (94%) of the 34 patients, which was significantly higher than that without LVO (chi 2 = 9.79, p = 0.0055). Furthermore, LVO revealed additional findings in nine patients such as mural thrombus or apical thinning. In total, LVO revealed abnormal apical findings in 22 patients (65%), which was significantly higher than that without LVO (chi 2 = 10.0, p = 0.0013). CONCLUSIONS: LVO is useful for identifying abnormal findings, especially in the apex in asymptomatic patients with negative T waves on ECG.

Aged↗
PubMed2001

FCCP depolarizes plasma membrane potential by activating proton and Na+ currents in bovine aortic endothelial cells.

We investigated the effects of carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP), a protonophore and uncoupler of mitochondrial oxidative phosphorylation in mitochondria, on plasma membrane potential and ionic currents in bovine aortic endothelial cells (BAECs). The membrane potential and ionic currents of BAECs were recorded using the patch-clamp technique in current-clamp and voltage-clamp modes, respectively. FCCP activated ionic currents and depolarized the plasma membrane potential in a dose-dependent manner. Neither the removal of extracellular Ca2+ nor pretreatment with BAPTA/AM affected the FCCP-induced currents, implying that the currents are not associated with the FCCP-induced intracellular [Ca2+]i increase. FCCP-induced currents were significantly influenced by the changes in extracellular or intracellular pH; the increased proton gradient produced by lowering the extracellular pH or intracellular alkalinization augmented the changes in membrane potential and ionic currents caused by FCCP. FCCP-induced currents were significantly reduced under extracellular Na+-free conditions. The reversal potentials of FCCP-induced currents under Na+-free conditions were well fitted to the calculated equilibrium potential for protons. Interestingly, FCCP-induced Na+ transport (subtracted currents, I(control)- I(Na+-free) was closely dependent on extracellular pH, whereas FCCP-induced H+transport was not significantly affected by the absence of Na+. These results suggest that the FCCP-induced ionic currents and depolarization, which are strongly dependent on the plasmalemmal proton gradient, are likely to be mediated by both H+ and Na+ currents across the plasma membrane. The relationship between H+ and Na+ transport still needs to be determined.

Animals↗
PubMed1999

Apolipoprotein Serum Amyloid A in Alzheimer's Disease.

Alzheimer's disease is characterized by the tissue deposition of beta-amyloid peptide (Abeta) in the brain. Recent studies have shown apoproteins (apo) in amyloid plaques and associated with high-density lipoprotein (HDL) particles in the cerebrospinal fluid (CSF). Western blot analysis revealed that serum amyloid A (apoSAA) protein was present in control and AD patients at low levels compared to apoE and apoA-I, however, AD brains showed a significant increase over control values. Analysis of CSF-HDL from control and AD individuals showed that apoA-I, apoE and apoSAA were on the particle. Immuno-cytochemical analysis showed that SAA was detected in senile plaques in AD tissue, but was predominantly localized to neuritic plaques. ApoE staining of AD brain confirmed that most plaques contained the apoprotein, similar to Abeta immunoreactivity, whereas apoA-I expressed little staining of senile plaques. No significant differences were detected in the level of apoSAA when compared to APOE genotype in AD samples, suggesting that interactions with apoE were non-specific. These data imply that the specific interactions of SAA with Abeta in the neuritic plaques may play a role in AD.

Journal Article↗
PubMed1998

Changes of lipid metabolism in plasma, liver and bile during cholesterol gallstone formation in rabbit model.

AIM:To find out the relationship between the disturbances of lipid metabolism and the formation of cholesterol gallstones by studying the changes of lipid metabolism in plasma, liver tissue and the bile.METHODS:Male and female white Japanese rabbits were divided randomly into a control group (Con) and four experimental groups of 10 rabbits each fed with a diet containing 1.2% cholesterol for one, two, three and four weeks (1wk, 2wk, 3wk and 4wk group). The measurement of plasma triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and its subfractions (HDL(2)-C, HDL(3)-C), very low and low density lipoprotein cholesterol (VLDL-C, LDL-C) was taken with standard enzymatic techniques. Apolipoprotein (apo) concentrations in plasma were measured by radial immunodiffusion assay for apoA1, apoB100, aopCII and apoC . Total cholesterol of liver was measured by the enzymatic procedure for each animal.Bile acids, mainly glycocholate (GCA) and glycodeoxycholate (GDCA) were detected by dual wavelength thin layer scanner.RESULTS:In all the experimental groups fed with dietary cholesterol, cholesterol crystal was found in the gallbladder in 2/10 cases of the 1wk group, 4/10 of the 2wk group,6/10 of the 3wk group and 7/10 of the 4wk group respectively. The concentration of plasma total cholesterol (TC),triglyceride (TG), phospholipid (pl), VLDL-C, LDL-C, apoB100, apoCII, apoC gradually increased (P < 0.05)with the prolonged feeding time of dietary cholesterol. High density lipoprotein cholesterol and its subfractions (HDL(2)-C, HDL(3)-C) showed a tendency to decrease, but without statistical significance (P > 0.05). ApoA1 was reduced with increased feeding time of dietary cholesterol (P < 0.05).The hepatic and biliary cholesterol increased 1-1.5 times as compared with the control group (t =5.221 and 3.445, P < 0.05).The GCA gradually decreased beginning from the control group to the 4wk group (P <0.05).CONCLUSION:Owing to the high cholesterol diet, the increased concentrations of plasma TC, TG, VLDL-C, LDL-C, hepatic TC and TG, apoB100, apoCII and apoC possibly enhanced the secretion of biliary cholesterol into bile; the decreased plasma apoA1 level might reduce the secretion of antinucleating factor into bile.All those factors mentioned above probably contribute to the formation of cholesterol gallstones.

Journal Article↗
PubMed1997

Effects of Insulin and cAMP on the High Density Lipoprotein Receptor in Cultured Human Arterial Smooth Muscle Cells.

Effects of insulin and cyclic AMP (cAMP) on HDL binding to cultured human arterial smooth muscles cells (SMC) were studied. Twenty-four hours after adding insulin to SMC cultured medium, the B(max) was decreased by 18% when compared with the control (P<0.05). On the other hand, twenty-four hours after adding db-cAMP to SMC cultured medium, the B(max) value was unchanged, but K(d) value was decreased 34% when compared with the control (P<0.001). The results suggested that insulin could induce the down regulation of the high density lipoprotein receptor and cAMP could promote HDL3 binding to SMC HDL receptor by increasing the affinity of the receptor in cultured human SMC.

Journal Article↗
PubMed1989

The K1 Toxin of Saccharomyces cerevisiae Kills Spheroplasts of Many Yeast Species.

The Saccharomyces cerevisiae K1 toxin killed spheroplasts from the genera Candida, Kluyveromyces, and Schwanniomyces. Cells of these organisms were toxin insensitive. The toxin bound poorly to Kluyveromyces lactis cells. In contrast, Candida albicans bound the toxin to an extent similar to that seen with S. cerevisiae. Thus, wall receptors can define toxin specificity and are necessary but not sufficient for toxin action on intact cells.

Journal Article↗
PubMedDate not supplied

Methyl parathion increases neuronal activities in the rat locus coeruleus.

Exposure to organophosphate insecticides induces undesirable behavioral changes in humans, including anxiety and irritability, depression, cognitive disturbances and sleep disorders. Little information currently exists concerning the neural mechanisms underlying such behavioral changes. The brain stem locus coeruleus (LC) could be a mediator of organophosphate insecticide-induced behavioral toxicities since it contains high levels of acetylcholinesterase and is involved in the regulation of the sleep-wake cycle, attention, arousal, memory, and pathological processes, including anxiety and depression. In the present study, using a multi-wire recording technique, we examined the effects of methyl parathion, a commonly used organophosphate insecticide, on the firing patterns of LC neurons in rats. Systemic administration of a single dose of methyl parathion (1 mg/kg, i.v.) increased the spontaneous firing rates of LC neurons by 240% but did not change the temporal relationships among the activities of multiple LC neurons. This dose of methyl parathion induced a 50% decrease in blood acetylcholinesterase activity and a 48% decrease in LC acetylcholinesterase activity. The methyl parathion-induced excitation of LC neurons was reversed by administration of atropine sulfate, a muscarinic receptor antagonist, indicating an involvement of muscarinic receptors. The methyl parathion-induced increase in LC neuronal activity returned to normal within 30 min while the blood acetylcholinesterase activity remained inhibited for over 1 h. These data indicate that methyl parathion treatment can elicit excitation of LC neurons. Such excitation could contribute to the neuronal basis of organophosphate insecticide-induced behavioral changes in human.

Acetylcholinesterase↗
PubMedDate not supplied

A comparison of cholinesterase activity after intravenous, oral or dermal administration of methyl parathion.

Time-dependent changes in blood cholinesterase activity caused by single intravenous, oral or dermal administration of methyl parathion to adult female rats were defined. Intravenous and oral administration of 2.5 mg/kg methyl parathion resulted in rapid (<60 min) decreases in cholinesterase activity which recovered fully in vivo within 30-48 h. In contrast, spontaneous reactivation of cholinesterase in vitro was complete within 6 h at 37 degrees C. Dermal administration of methyl parathion caused dose-dependent inhibition of cholinesterase activity which developed slowly (> or =6 h) and was prolonged (> or =48 h). Time- and route-dependent effects of methyl parathion on cholinesterase activity in brain and other tissues generally paralleled its effects on activity in blood. In conclusion, pharmacodynamics of methyl parathion differ substantially with route of exposure. Recovery of cholinesterase in vivo after intravenous or oral exposure may partially reflect spontaneous reactivation and suggests a rapid clearance of methyl parathion or its active metabolite methyl paraoxon. The more gradual and prolonged inhibition of cholinesterase caused by dermal administration is consistent with disposition of methyl parathion at a site from which it or methyl paraoxon is only slowly distributed. Thus, dermal exposure to methyl parathion may pose the greatest risk for long-term adverse effects.

Administration, Cutaneous↗
PubMedDate not supplied

Essential roles of lipoxygenases in LDL oxidation and development of atherosclerosis.

Oxidative modification of low-density lipoprotein (LDL) is one of the critical steps for the development of atherosclerosis. Accumulating studies have indicated that 12/15-lipoxygenase highly expressed in macrophages plays an essential role in the oxidation of circulating LDL. It has been demonstrated that LDL needs to bind the LDL receptor-related protein (LRP), a cell-surface receptor, prior to its oxidation by 12/15-lipoxygenase expressed in macrophages. LRP is suggested to mediate the selective transfer of cholesteryl ester in LDL to the plasma membrane of macrophages without endocytosis and degradation of the LDL particle. At the same time, binding of LDL to LRP translocates the 12/15-lipoxygenase from the cytosol to the plasma membrane. It is also demonstrated that 5-lipoxygenase localized in macrophages generates leukotrienes, which exhibit strong proinflammatory activities in cardiovascular tissues and contribute to lesion development. Therefore, the inhibition of these lipoxygenases may be effective in the prevention and treatment of the inflammatory diseases.

Animals↗
PubMedDate not supplied

Langerhans cell histiocytosis of the thyroid diagnosed by fine needle aspiration cytology. A case report.

BACKGROUND: Langerhans cell histiocytosis rarely involves the thyroid gland even in patients with multifocal disease. Unifocal disease apparently confined to the thyroid is even more rare. CASE: A 30-year-old woman presented with a 6-cm mass in the right and a 3-cm mass in the left lobe of the thyroid. Fine needle aspiration cytology showed isolated, loose aggregates and histiocytelike cells with grooved or contorted nuclei mixed in varying proportions with many mature eosinophils, scattered and small lymphocytes, multinucleated giant cells and foamy histiocytes. CONCLUSION: The cytologic features of Langerhans cell histiocytosis are characteristic. A fine needle aspiration cytology diagnosis is confirmed by histopathologic studies, imunohistochemical staining and ultrastructural studies.

Adult↗
PubMedDate not supplied

Freeze-drying of human platelets: influence of intracellular trehalose and extracellular protectants.

Freeze-drying is an ideal alternative for long-term preservation of platelets in blood banks. Intracellular trehalose is believed to be an effective lyoprotectant for preserving cells during freeze-drying. In this study, 13 mM intracellular trehalose was loaded into human platelets through fluid-phase endocytosis pathway. Bovine serum albumin and trehalose were used as extracellular protectants. The effects of intracellular trehalose and extracellular protectants on freeze-dried platelets were studied respectively. The results showed 13 mM intracellular trehalose was beneficial to freeze-dried human platelets, but only slightly enhanced the protection afforded by extracellular protectants. Loaded with 13 mM intracellular trehalose, platelets were freeze-dried in a formulation of 1 percent bovine serum albumin and 1 percent trehalose, 40 days later, the survival rate of rehydrated platelets was about 85 percent, the morphology of rehydrated platelets was intact and the aggregation percentage with thrombin (1 U/ml) was 97.3 percent.

Blood Platelets↗