Biomedical subjects

Z Lu

Publications and source records attributed to Z Lu.

At least 217 records · Page 12Linked to original sources

PubMed1999

Enhanced inhibition of human immunodeficiency virus type 1 by Met-stromal-derived factor 1beta correlates with down-modulation of CXCR4.

CXCR4 is a chemokine receptor used by some strains of HIV-1 as an entry coreceptor in association with cell surface CD4 on human cells. In human immunodeficiency virus type 1 (HIV-1)-infected individuals, the appearance of viral isolates with a tropism for CXCR4 (T tropic) has been correlated with late disease progression. The presumed natural ligands for CXCR4 are SDF-1alpha and SDF-1beta, which are proposed to play a role in blocking T-tropic HIV-1 cell entry. Here, we demonstrate that addition of an N-terminal methionine residue to SDF-1beta (Met-SDF-1beta) results in a dramatically enhanced functional activity compared to that of native SDF-1beta. Equivalent concentrations of Met-SDF-1beta are markedly more inhibitory for T-tropic HIV-1 replication than SDF-1beta. A comparison of the biological activities of these two forms of SDF-1beta reveals that Met-SDF-1beta induces a more pronounced intracellular calcium flux yet binds with slightly lower affinity to CXCR4 than SDF-1beta. Down-modulation of CXCR4 is similar after exposure of cells to either chemokine form for 2 h. However, after a 48-h incubation, the surface expression of CXCR4 is much lower for cells treated with Met-SDF-1beta. The enhanced blocking of T-tropic HIV-1 by Met-SDF-1beta appears to be related to prolonged CXCR4 down-modulation.

Amino Acid Sequence↗

PubMed1999

Antagonistic effects of protein kinase C alpha and delta on both transformation and phospholipase D activity mediated by the epidermal growth factor receptor.

Downregulation of protein kinase C delta (PKC delta) by treatment with the tumor-promoting phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) transforms cells that overexpress the non-receptor class tyrosine kinase c-Src (Z. Lu et al., Mol. Cell. Biol. 17:3418-3428, 1997). We extended these studies to cells overexpressing a receptor class tyrosine kinase, the epidermal growth factor (EGF) receptor (EGFR cells); like c-Src, the EGF receptor is overexpressed in several human tumors. In contrast with expectations, downregulation of PKC isoforms with TPA did not transform the EGFR cells; however, treatment with EGF did transform these cells. Since TPA downregulates all phorbol ester-responsive PKC isoforms, we examined the effects of PKC delta- and PKC alpha-specific inhibitors and the expression of dominant negative mutants for both PKC delta and alpha. Consistent with a tumor-suppressing function for PKC delta, the PKC delta-specific inhibitor rottlerin and a dominant negative PKC delta mutant transformed the EGFR cells in the absence of EGF. In contrast, the PKC alpha-specific inhibitor Go6976 and expression of a dominant negative PKC alpha mutant blocked the transformed phenotype induced by both EGF and PKC delta inhibition. Interestingly, both rottlerin and EGF induced substantial increases in phospholipase D (PLD) activity, which is commonly elevated in response to mitogenic stimuli. The elevation of PLD activity in response to inhibiting PKC delta, like transformation, was dependent upon PKC alpha and restricted to the EGFR cells. These data demonstrate that PKC isoforms alpha and delta have antagonistic effects on both transformation and PLD activity and further support a tumor suppressor role for PKC delta that may be mediated by suppression of tyrosine kinase-dependent increases in PLD activity.

Acetophenones↗

PubMed1999

[Effects of protocol HX-97 on mobilization, collection and hematopoietic reconstitution of peripheral blood stem cells transplantation].

In order to enhance the effects of peripheral blood stem cell mobilization, collection and hematopoietic reconstitution, we observed and evaluated the effects of Protocol HX-97 on 22 patients who received allogeneic or autologous peripheral blood stem cell transplants from April 1997 to June 1999. rhG-CSF was used for mobilization at a dose of 300 micrograms/day for 6 days; the sixth dose was given an hour and a half before leukapheresis. High dose chemotherapy and rhG-CSF were given for autologous peripheral blood stem cell mobilization; the chemotherapy should be intensive enough to reduce the patients' peripheral WBC to less than 1.0 x 10(9)/L, and the beginning of using rhG-CSF should be just at the time of WBC's rising from the nadir. rhGM-CSF and rhG-CSF were given sequentially for hematopoietic reconstitution after transplantation. The results showed that leukaphereses were successfully performed for peripheral blood stem cell collection. Sixteen cases needed apheresis only once, and 6 cases needed it twice. The harvests were 2.5-10.7 x 10(8)/kg MNC, 2.5-20.0 x 10(6)/kg CD34+ cells (including 1.8-7.5 x 10(6)/kg CD34+CD33-, 0.7-12.5 x 10(6)/kg CD34+CD33+), and 3.5-6.3 x 10(5)/kg CFU-GM. Hematopoietic function recovered to > 0.5 x 10(9)/L of neutrophil count in allo-PBSCT at 14-20 days and in auto-PBSCT at 12-20 days, and to > 20 x 10(9)/L of platelet count in allo-PBSCT and in auto-PBSCT at 16-34 days and 16-28 days, respectively. At day +30 post-transplantation, chromosome analysis and DNA finger print assessment of bone marrow cells indicated that the patients' hematopoietic function had been reconstituted. This study suggests that Protocol HX-97 is an effective approach to mobilization of peripheral blood stem cell transplantation, and it is relatively cost-effective.

Adult↗

PubMed1999

Carpal tunnel syndrome: a retrospective analysis of 262 cases and a one to one matched case-control study of 61 women pairs in relationship between manual housework and carpal tunnel syndrome.

OBJECTIVES: To get a more comprehensive recognition about carpal tunnel syndrome (CTS), especially the manual housework as its risk factor, and to facilitate early diagnosis and proper treatment. METHODS: 262 CTS patients (396 CTS hands) were analyzed retrospectively. A 1:1 matched case-control study of 61 woman pairs in relationship between manual housework and the occurrence of CTS was carried out. RESULTS: In 262 CTS patients, 84% were female, and the dominant hand was more frequently affected; repetitive and forceful movement of the hand and wrist might be associated with CTS. Typical clinical manifestations include pain and paresthesia in the median nerve territory, but 75.3% of our 396 CTS hands had all five digits involved. Conduction abnormalities appeared selectively in the median nerve distal to the wrist. In the case-control study, for manual washing, rolling or kneading dough, and knitting woolen sweater, the odds ratios (OR) of CTS between high and low intensities were 3.86 (95% confidence interval 1.79-8.33, chi 2 = 11.76, P < 0.01), 6.25 (95% confidence interval 2.50-15.63, chi 2 = 15.21, P < 0.01) and 1.13 (95% confidence interval 0.57-2.22, chi 2 = 0.125, P > 0.05) respectively; and those between long and short duration (i.e. the number of years engaging in these manual housework) were 2.33 (95% confidence interval 0.63-8.64, chi 2 = 1.6, P > 0.05), 1.88 (95% confidence interval 0.81-4.38, chi 2 = 2.13, P > 0.05) and 1 (chi 2 = 0, P > 0.05). CONCLUSIONS: The diagnosis of CTS requires confirmation of illness history, symptoms and signs with objective electrodiagnostic tests. Manual washing and rolling or kneading dough might be associated with the onset of CTS.

Adult↗

PubMed1999

[Cells culture of human lumbar disc and its morphological observation].

OBJECTIVE: To observe the continuous changes of disc cells, and explore the degeneration influenced by the cell effects. METHODS: Three discs were obtained from three human embryos and one was from a healthy adult. They were dissected and were digested with trypsin and collagenase. The isolated cells were cultured in HAM F-12 medium and 10% fetal bovine serum. The cultured cells were refrigerated and revived for observation under light microscope and TEM. RESULTS: The biological characteristics of the primary and the second generation of the disc cells were similar to those of the cells in vivo. After subculture, notochordal cells and chondrocytes were shown the characteristics of dedifferentiation. The metabolism of the revived cells after refrigeration was normal. The structures of the organellae in disc cells varied with the changes of cell biological characteristics. CONCLUSION: This successful model is useful for the study of biology and pharmacology of human disc cells.

Adult↗

PubMed1999

[Remnant abnormal clonal hematopoiesis in patients with paroxysmal nocturnal hemoglobinuria of clinical remission].

OBJECTIVE: To observe the abnormal clonal hematopoiesis status in patients with paroxysmal nocturnal hemoglobinuria(PNH) attained complete clinical remission(CCR). METHODS: Immunofluorescence labeling and flow cytometry were used to detect the expression of CD59 in bone marrow mononuclear cells and peripheral red blood cell and the number of bone marrow CD34+ hematopoietic stem/progenitor cells. RESULTS: In two patients in CCR, the coexistence of normal and abnormal hematopoiesis could still be found. However, the percentage of normal cells with CD59+ phenotype in peripheral red blood cells, bone marrow mononuclear cells and CD34+ hematopoietic stem/progenitor cells were significantly higher as compared with those in patients without remission, indicating that the normal hematopoiesis gradually regained dominance over the abnormal one when the disease approached remission. CONCLUSIONS: In PNH patients in CCR, remnant abnormal (CD59-) cells could still be found in peripheral blood and bone marrow. It seems not necessary to climinate thoroughly all abnormal clones to achieve CCR in patients with PNH, and the dominance of abnormal hematopoicsis could vanish under some presently unknown mechanism.

Antigens, CD34↗

PubMed1999

[Relative analysis of the mRNA expression between endothelin and inducible nitric oxide synthase in pulpitis].

OBJECTIVE: To study the relationship between endothelin-1(ET-1) and inducible nitric oxide synthase (iNOS) through the mRNA expression in pulpitis. METHODS: The model of experimental rat pulpitis; extraction of RNA, the reverse-polymerase chain reaction(RT-PCR) were used. RESULTS: The mRNA expression of ET-1/iNOS in pulpitis groups was higher than the control. There was relationship in the mRNA expression between ET-1 and iNOS. CONCLUSION: Pulp microcirculation was mechanized by the contraction and relaxtion of ET-1/iNOS, which could have direct effects on the pathological change. The control mechanism was due to the up-regulation of ET-1/iNOS gene in transcription level.

Animals↗

PubMed1999

[Effect of puerarin on coronary collateral circulation in dogs with experimental acute myocardial infarction].

OBJECTIVE: To evaluate the effect and mechanism of puerarin on coronary collateral circulation in dogs with experimental acute myocardial infarction. METHOD: Twelve dogs were randomly divided into puerarin (Gegen su, G) group and control(C) group, the acute myocardial infarction model was built in all dogs. Puerarin or saline was administered for 21 days. Coronary angiography was performed before and after ligating coronary artery. The capillaries and distribution vessel density in tissue sections of myocardium were assessed. RESULT: Angiography on hour 2 and day 22 after ligating coronary artery revealed significant augmentation of collateral vessels in G group versus controls. Capillaries and distribution vessel density in ischemic and infarctive zone on day 22 revealed statistically significant augmentation in G group versus controls (P < 0.05 and P < 0.01). CONCLUSION: Puerarin might improve the opening and forming of coronary collateral circulation to ischemic myocardium in dogs and protect ischemic myocardium.

Animals↗

PubMed1999

[Studies on immunomodulatory function of polysaccharide of Fructus Ligustri Lucidi].

OBJECTIVE: To explore the immunomodulatory mechanism of Chinese medicine Fructus Ligustri Lucidi and to find its efficient material base. METHOD: The effects of FLLPS on the immunoactivity of mouse speen lymphocyte were studied in vitro or vivo by means of MTT. RESULT: FLLPS could obviously promote the speen lymphocyte proliferation in normal mice and mice with Yin-deficiency selected by injection with adrenocorticortropic hormone. CONCLUSION: FLLPS has an immunomodulatory function for both normal mice and mice with Yin-deficiency.

Adjuvants, Immunologic↗

PubMed1999

[Diagnostic value of ultrasonography in cervical lymph node metastasis].

OBJECTIVE: To research the accuracy of ultrasonography in the diagnosis of cervical lymph node metastasis and the value of that of cervical lymph node occult metastasis. METHOD: Fifty-five patients(61 sides) operated by neck dissection were double-blindedly studied by preoperation palpation and ultrasonography comparing with postoperating pathological examination. RESULT: Fifty-two sides were confirmed to be pathology lymph node metastasis from 61 sides. 40 and 48 sides were checked out by palpation and ultrasonography, respectively. The sensitivity, specificity and accuracy of palpation and ultrasonography were 76.9% and 92.3% (P < 0.05), 77.8% and 88.9%(P > 0.05) and 77.0% and 91.8%(P < 0.05), respectively. Six sides were checked out by ultrasonography (occult metastasis) in 12 sides of palpation negative. CONCLUSION: The accuracy of ultrasonography was prior to that of palpation in examining cervical lymph node metastsis. Ultrasonography could check out about half occult metastasis and should be regarded as a routine examining items in diagnosing cervical lymph node metastasis.

Adult↗

PubMed1999

[Improvements on radical neck dissection].

OBJECTIVE: To improve the surgery of radical neck dissection for a better curative effect. METHOD: Some improvements on incision, path to exploration and manipulation of operation were made in 65 patients with head and neck tumors while radical neck dissection were done. RESULT: The average surgical time was 110 minutes and the average amount of bleeding was 120 ml in the patients when radical neck dissection had been completed. The complications decreased to 1.54%. The surviual rates of 2 and 3 years are 86.2% (56/65) and 81.6 (31/38) respectively. CONCLUSION: With these improvements on radical neck dissection, the curative effect in the near future is improved.

Adolescent↗

PubMed1999

[Study on chemical constituents of essential oil of Michelia leaves by gas chromatography-mass spectrometry].

The essential oil in Michelia leaves was extracted by steam distillation. The oil obtained was dried with anhydrous magnesium sulfate. The chemical constituents were analyzed by GC-MS. Thirty three peaks were separated by GC, and 27 of them were identified by MS with NBS mass spectral data and Wiley/NBS registry of mass spectral data. The structure of linalool was further verified by GC/FTIR. The identified constituents represent 97% of the peak area of the essential oil on FID. The major chemical constituent of them are linalool, trans-caryophyllene and diethyl-o-phthalate.

Acyclic Monoterpenes↗

PubMed1999

[Effects of chitin and chitosan on degradation of DL-polylactide in vitro].

The authors assessed the variations of pH-values of the physiological saline used for in vitro degradation tests of DL-Polylactide (DL-PLA)/chitin and DL-PLA/chitosan composites and DL-PLA. The weight-loss rations, the appearance and morphology of the tested specimens, and the molecular weights of DL-PLA in composites and pure DL-PLA were alse investigated. The results showed that both chitin and chitosan had significant inhibitory effects on the degradation of DL-PLA, and the effect of chitosan was stronger than that of chitin. A discussion on the mechanism of such inhibition is presented.

Biocompatible Materials↗

PubMed1999

[Determination of itaconic acid in culture broth by high performance liquid chromatography].

An HPLC method for the determination of itaconic acid and other components in the culture broth of Aspergillus terreus was developed. The operating conditions were Aminex HPX-87H column (300 mm x 7.8 mm) at 30 degrees C, mobile phase of sulfuric acid (4 mmol/L) and refractive index detector at 30 degrees C. The linear relationship of calibration curve was good in the range of 0-50 g/L for itaconic acid (r = 0.9997). The detection limit was 5.7 micrograms, and the relative standard deviation was 1.37% (n = 7). Other components in the culture broth were SO(4)2-, sucrose, glucose and fructose. The method is simple, sensitive, rapid and accurate.

English Abstract↗

PubMed1999

[Production of neutral beta-mannanase by Bacillus subtilis and its properties].

Neutral beta-mannanase was produced by Bacillus subtilis BM9602 isolated from a soil. For this strain the neutral beta-mannanase was produced only when polysaccharides were used as a carbon source. Organic nitrogen source was superior to inorganic nitrogen source on the enzyme production. The optimum liquid medium consisted of 4% konjak powder, 1% each of beef peptone and yeast extract. The optimum culture conditions were initial pH 8.5, temperature 35 degrees C and cultivation time 36 h. Enzyme activity of culture filtrate to 0.5% galactomannan polysaccharide was 96 IU/mL per minute at pH 6.0 and 50 degrees C for 10 min. The optimum pH and temperature for enzyme action were 6.0 and 50 degrees C respectively. The enzyme was stable below 50 degrees C and pH 5.0-10.0. The enzyme hydrolyzed konjak powder and locust bean gum to form oligosaccharides.

Bacillus subtilis↗

PubMed1999

[The effect of interleukin-1 beta on cell growth of normal mouse pituitary cells and ACTH secreting adenoma].

OBJECTIVE: To investigate whether IL-1 beta could affect the cell proliferation of normal pituitary cells and ACTH secreting adenoma cells. METHODS: Normal mouse pituitary cells were cultured in mininum essential medium-D-valine medium, a cultures virtually free of fibroblasts. AtT20 cells were also cultured as an ACTH secreting adenoma model. MTT method was used to study 10(-9) mol/L-10(-13) mol/L IL-1 beta effect on both normal and adenoma cells growth. RESULTS: (1) In the primate cells culture of normal mouse pituitary, IL-1 beta failed to influence cell growth during a period of 72 hours (n = 9, P > 0.05). This finding can not confirm that IL-1 beta has no effect on pituitary cell growth, because of the variety of cell types in pituitary. (2) In the AtT20 cells, 10(-9) mol/L-10(-13) mol/L IL-1 beta stimulated cell proliferation significantly after 48 and 72 hours culturing respectively (n = 9, P < 0.05, P < 0.01). CONCLUSIONS: These results suggested that IL-1 beta might be partially in involved in modulating pituitary adenoma cells growth.

Adenoma↗

PubMed1998

Murine hepatitis virus strain 3 induces the macrophage prothrombinase fgl-2 through p38 mitogen-activated protein kinase activation.

The clinical syndrome of acute liver failure produced by fulminant viral hepatitis can be reproduced in mice by infection with murine hepatitis virus strain 3 (MHV-3). Although it is clear that MHV-3-induced hepatitis depends upon macrophage activation and the expression of a specific prothrombinase, fgl-2, the signaling pathways involved in virally stimulated cell activation are unclear. Since we had previously found that MHV-3 induces the tyrosine phosphorylation of cellular proteins, we investigated the roles of the mitogen-activated protein kinase (MAPK) proteins. In a series of Western blots, immunoprecipitation and in vitro kinase assay studies, we found that both the extracellular signal-related kinase (ERK) and p38 MAPK proteins are tyrosine-phosphorylated and activated following exposure of murine peritoneal exudative macrophages (PEM) to MHV-3. Although p38 phosphorylation and activity are induced soon after MHV-3 exposure, peaking by 1-5 min, ERK phosphorylation and activity increase more gradually, peaking at 20-30 min and gradually fading thereafter. Interestingly, whereas selective p38 inhibition with SB203580 (1-20 microM) abolished the virally stimulated induction of fgl-2 mRNA, protein, and functional activity, selective ERK inhibition with PD98059 (1-50 microM) limited fgl-2 functional activity but had little to no effect on fgl-2 mRNA or protein levels. Moreover, whereas inhibition of ERK had no effect on p38 activity, p38 inhibition consistently increased MHV-3-induced ERK activity. To ensure that these pathways were relevant in vivo, MHV-3 was injected intraperitoneally, and peritoneal exudative macrophages were collected. Again, MHV-3 exposure led to increased p38 and ERK tyrosine phosphorylation. These data argue that MHV-3 induces tightly interconnected ERK and p38 MAPK cascades in the macrophage both in vitro and in vivo. Although the ERK and p38 MAPK proteins have discordant effects at the level of fgl-2 expression, both converge at the level of its activity, suggesting that targeted MAPK inhibition may ultimately be useful in the modulation of viral hepatitis.

Animals↗

PubMed1998

Protein folding activity of Hsp70 is modified differentially by the hsp40 co-chaperones Sis1 and Ydj1.

Specification of Hsp70 action in cellular protein metabolism may occur through the formation of specialized Hsp70:Hsp40 pairs. To test this model, we compared the ability of purified Sis1 and Ydj1 to regulate the ATPase and protein-folding activity of Hsp70 Ssa1 and Ssb1/2 proteins. Ydj1 and Sis1 could both functionally interact with Ssa1, but not the Ssb1/2 proteins, to refold luciferase. Interestingly, Ydj1:Ssa1 could promote up to four times more luciferase folding than Sis1:Ssa1. This functional difference was explored and could not be accounted for by differences in the ability of Sis1 and Ydj1 to regulate Ssa1 ATPase activity. Instead, differences in the chaperone function of Ydj1 and Sis1 were observed. Ydj1 was dramatically more effective than Sis1 at suppressing the thermally induced aggregation of luciferase. Paradoxically, Sis1 and Ydj1 could bind similar quantities of chemically denatured luciferase. The polypeptide binding domain of Sis1 was found to lie between residues 171-352 and correspond to its conserved carboxyl terminus. The conserved carboxyl terminus of Ydj1 is also known to participate in the binding of nonnative polypeptides. Thus, Ydj1 appears more efficient at assisting Ssa1 in folding luciferase because its contains a zinc finger-like region that is absent from Sis1. Ydj1 and Sis1 are structurally and functionally distinct Hsp40 proteins that can specify Ssa1 action by generating Hsp70:Hsp40 pairs that exhibit different chaperone activities.

Adenosine Triphosphatases↗