Biomedical subjects

M Zhu

Publications and source records attributed to M Zhu.

At least 127 records · Page 7Linked to original sources

PubMed2000

[Correlation between the changes of soft and hard tissue after advanced Lefort I osteotomy in patients with cleft lip and palate].

OBJECTIVE: The purpose is to evaluate the correlation between the changes of soft and hard tissue after advanced Lefort I osteotomy in patients with complete unilateral cleft lip and palate. METHODS: Lateral cephalometric films were taken from before and after operation. The same landmarks in two films were compared horizontally and vertically. The correlation ratio between changes of soft and hard tissue were analysed statistically. RESULTS: After operation, the length of upper lip of the patients with CLP increased. The ratio between the movement of upper incisor and upper lip was 0.77 horizontally and 0.67 vertically, respectively. CONCLUSION: The slope between hard and soft tissue was treated as ratio. It is more significant than the horizontal difference between soft and hard tissue, since correlative factor was contained in the slope.

English Abstract↗

PubMed2000

[Cephalometric analysis on patients with TMJ ankylosis in different ages].

OBJECTIVE: To determine the cephalometric characteristics of the patients with TMJ ankylosis in deferent ages and to find the relationship between the period with TMJ and the cephalometric characteristics. METHODS: By cephalometric analysis of 46 male patients with TMJ ankylosis and several normal people in deferent ages, we detected the relationship among the ages of the patients, the period with TMJ ankylosis and the cephalometric characteristics by means of SPSS for Win 95/98. RESULTS: The cephalometric characteristics of the patients showed their maxilla and mandible retruded in posterior and superior direction, the hyoid bone displaced posteriorly and inferiorly. The middle and inferior pharygeal space decreased, the TSA/OPA increased significantly. There was an obvious positive correlation between the period with TMJ and hyoid bone position(r=0.46, p=0.009; Y=1.58+0.56X), and remarkable positive correlation between the period with TMJ and TSA/OPA(r=0.5, p=0.00 Y=72.76+0.64X). CONCLUSION: In patients with TMJ ankylosis, the mandible and maxilla retruded posteriorly and superiorly,the hyoid bone displaced posteriorly and inferiorly, the middle and inferior pharygeal space decreased, the TSA/OPA increased remarkably. The longer the period with TMJ ankylosis, the more serious the deformities of the patients in craniomaxillofacial region.

English Abstract↗

PubMed2000

[A preliminary study on fimbriae subunits and molecular weight of actinomyces viscosus 5951]

OBJECTIVE:To preliminarily analyse the subunits and molecular weight of fimbriae of actinomyces viscosus 5951.METHODS:To do the immunoblotting test of the only II fimbriae type of mutant strain of T14V.RESULTS:It showed that there was only one 31ku band,which indicated that the fimbriae of actinomyces viscosus 5951 was composed of the same subunits of 31ku molecular weight. CONCLUSION:According to the previous reports and results of present study,the molecular weight of fimbriae of actinomyces viscosus 5951 was speculated to be 124ku and the fimbriae was composed of 4 same subunits.

Journal Article↗

PubMed1999

Transcription factor YY1 is a vaccinia virus late promoter activator.

Vaccinia virus has a DNA genome, yet replicates in the cytoplasmic compartment of the cell. We previously described the identification of a cellular protein having high affinity for vaccinia virus late promoter DNA. Sequence substitutions in the vaccinia I1L promoter were used to define a 5-nucleotide block at the transcription initiation site as essential for interaction with the protein. Within this sequence is the recognition motif for the nuclear transcription factor YY1. This factor regulates a multitude of cellular promoters, as an activator of transcription, as a repressor, or as an initiator element-binding protein. Antibodies directed against YY1 were used to show that YY1 copurified with the vaccinia late promoter-binding protein and was present in late promoter-protein complexes in gel supershift assays. Bacterially expressed YY1 also bound specifically to late promoter DNA. A dinucleotide replacement within the YY1 recognition motif directly adjacent to the transcription start site severely reduced the affinity of YY1 for the I1L promoter in vitro and impaired I1L promoter-dependent transcription in vivo. The intracellular localization of YY1 was shown by immunofluorescence microscopy to shift from primarily nuclear to the cytoplasm after vaccinia infection. These results indicate that YY1 has a positive role in the regulation of vaccinia virus late gene transcription and suggest that poxviruses have adapted cellular initiator elements as a means of regulating viral gene expression. This is the first identifiable cellular protein implicated in poxvirus transcription.

Base Sequence↗

PubMed1999

Release of mechanical tension triggers apoptosis of human fibroblasts in a model of regressing granulation tissue.

In an in vitro model of granulation tissue, early passage human diploid fibroblasts under mechanical tension showed little or no apoptosis. Release of mechanical tension triggered an apoptotic response that occurred within 3-6 h and reached a plateau by 24 h. The percentage of apoptotic cells (approximately 15%) remained constant up to 7 days, and after 3 days, total cell number declined. Identification of mechanical unloading as a stimulus for apoptosis, without application of pharmacologic or genetic intervention, is a novel observation that permits us to model similar events that occur during wound healing. Studies on the mechanism regulating apoptosis under these conditions established that the apoptotic response does not require differentiation of cells into myofibroblasts but is governed by a combination of mechanical tension and growth factors in the collagen matrix.

Actins↗

PubMed1999

A 29 kDa intracellular chloride channel p64H1 is associated with large dense-core vesicles in rat hippocampal neurons.

A novel class of intracellular chloride channels, the p64 family, has been found on several types of vesicles. These channels, acting in concert with the electrogenic proton pump, regulate the pH of the vesicle interior, which is critical for vesicular function. Here we describe the molecular cloning of p64H1, a p64 homolog, from both human and cow. Northern blot analysis showed that p64H1 is expressed abundantly in brain and retina, whereas the other members of this family (e.g., p64 and NCC27) are expressed only at low levels in these tissues. Immunohistochemical analysis of p64H1 in rat brain, using an affinity-purified antibody, revealed a high level of expression in the limbic system-the hippocampal formation, the amygdala, the hypothalamus, and the septum. Immunoelectron microscopic analysis of p64H1 in hippocampal neurons demonstrated a striking association between p64H1 and large dense-core vesicles (LDCVs) and microtubules. In contrast, very low p64H1 labeling was found in perikarya or associated with small synaptic vesicles (SSVs) in axonal profiles. Immunoblot analysis confirmed that p64H1 is colocalized with heavy membrane fractions containing LDCVs rather than the fractions containing SSVs. These results suggest that p64H1-mediated Cl- permeability may be involved in the maintenance of low internal pH in LDCVs and in the maturation of LDCVs and the biogenesis of functional neuropeptides.

Amino Acid Sequence↗

PubMed1999

The translation initiation factor, hu-Sui1 may be a target of hepatitis B X antigen in hepatocarcinogenesis.

The role of hepatitis B virus X antigen in the development of hepatocellular carcinoma was explored by stably transfecting HepG2 cells with an X antigen expression vector, and identifying the differences in gene expression that distinguish X positive from X negative cells by subtractive PCR. One differentially expressed gene, the human homolog of sui1 (hu-sui1), encodes a translation initiation factor whose expression was suppressed by X antigen in HepG2 cells. Hu-Sui1 was also expressed in nontumor liver but not in tumor cells from patients with hepatocellular carcinoma. Introduction of hu-sui1 into HepG2 cells inhibited cell growth in culture, in soft agar, and partially inhibited tumor formation in nude mice. Hence, the suppression of hu-sui1 by X antigen may result in the abrogation of negative growth regulation and contribute to the development of hepatocellular carcinoma.

Amino Acid Sequence↗

PubMed1999

Angiotensin II type 1 receptor-mediated inhibition of K+ channel subunit kv2.2 in brain stem and hypothalamic neurons.

Angiotensin II (Ang II) has powerful modulatory actions on cardiovascular function that are mediated by specific receptors located on neurons within the hypothalamus and brain stem. Incubation of neuronal cocultures of rat hypothalamus and brain stem with Ang II elicits an Ang II type 1 (AT1) receptor-mediated inhibition of total outward K+ current that contributes to an increase in neuronal firing rate. However, the exact K+ conductance(s) that is inhibited by Ang II are not established. Pharmacological manipulation of total neuronal outward K+ current revealed a component of K+ current sensitive to quinine, tetraethylammonium, and 4-aminopyridine, with IC50 values of 21.7 micromol/L, 1.49 mmol/L, and 890 micromol/L, respectively, and insensitive to alpha-dendrotoxin (100 to 500 nmol/L), charybdotoxin (100 to 500 nmol/L), and mast cell degranulating peptide (1 micromol/L). Collectively, these data suggest the presence of Kv2.2 and Kv3.1b. Biophysical examination of the quinine-sensitive neuronal K+ current demonstrated a macroscopic conductance with similar biophysical properties to those of Kv2.2 and Kv3.1b. Ang II (100 nmol/L), in the presence of the AT2 receptor blocker PD123,319, elicited an inhibition of neuronal K+ current that was abolished by quinine (50 micromol/L). Reverse transcriptase-polymerase chain reaction analysis confirmed the presence of Kv2.2 and Kv3.1b mRNA in these neurons. However, Western blot analyses demonstrated that only Kv2.2 protein was present. Coexpression of Kv2.2 and the AT1 receptor in Xenopus oocytes demonstrated an Ang II-induced inhibition of Kv2.2 current. Therefore, these data suggest that inhibition of Kv2.2 contributes to the AT1 receptor-mediated reduction of neuronal K+ current and subsequently to the modulation of cardiovascular function.

Angiotensin II↗

PubMed1999

Rapid development of glutathione-S-transferase-dependent drug resistance in vitro and its prevention by ethacrynic acid.

Exposure of A2780 human ovarian tumor cells to a low concentration of melphalan in vitro for 7 days resulted in the development of melphalan resistance. This resistance was not a stable characteristic of the cells since it was lost after 2 weeks in culture in the absence of drug. The melphalan-resistant cells exhibited significant cross-resistance to cisplatin but only minor cross-resistance to doxorubicin. The resistant cells had elevated levels of glutathione-S-transferase activity and mRNA. Exposure of the cells to the ethacrynic acid resulted in a decrease in enzyme activity as well as a reversal of their drug-resistant phenotype, indicating that the enzyme is involved in the resistance. When ethacrynic acid was present during the 7-day exposure of the cells to melphalan, the development of drug resistance was prevented. This system may serve as a useful preliminary step in screening for agents which can prevent the development of chemotherapy-induced drug resistance in human cancer.

Antineoplastic Agents, Alkylating↗

PubMed1999

Expression of the hepatocyte growth factor-like protein gene in human hepatocellular carcinoma and interleukin-6-induced increased expression in hepatoma cells.

Human hepatocellular carcinoma is one of the most frequent malignant tumors. It may occur following exposure to various agents, including viruses and chemical carcinogens; however, the underlying mechanisms of the hepatocarcinogenesis are not known. The present study is the result of our search for genes which may be abundantly expressed in human primary liver carcinoma. One of these genes was found to encode the human hepatocyte growth factor-like protein (HGFLP), also known as macrophage-stimulating protein. HGFLP is structurally homologous to hepatocyte growth factor, a potent growth factor for liver. HGFLP mRNA was also found to be overexpressed in a hepatoblastoma sample and in a sample of subacute fulminant hepatic necrosis. In a study on the effects of cytokines on the expression of HGFLP, we found that IL-6 increased expression of HGFLP mRNA in Hep G2 cells, but IL-1alpha, IL-1beta and TNF-alpha had no effect. An increase in HGFLP could be the result of inflammation and/or tissue injury and its overexpression may prove to be useful as an indicator of hepatoma.

Blotting, Northern↗

PubMed1999

Functional association of Nmi with Stat5 and Stat1 in IL-2- and IFNgamma-mediated signaling.

Using the coiled-coil region of Stat5b as the bait in a yeast two-hybrid screen, we identified the association of Nmi, a protein of unknown function previously reported as an N-Myc interactor. We further show that Nmi interacts with all STATs except Stat2. We evaluated two cytokine systems, IL-2 and IFNgamma, and demonstrate that Nmi augments STAT-mediated transcription in response to these cytokines. Interestingly, Nmi lacks an intrinsic transcriptional activation domain; instead, Nmi enhances the association of CBP/p300 coactivator proteins with Stat1 and Stat5, and together with CBP/p300 can augment IL-2- and IFNgamma-dependent transcription. Therefore, our data not only reveal that Nmi can potentiate STAT-dependent transcription, but also suggest that it can augment coactivator protein recruitment to at least some members of a group of sequence-specific transcription factors.

CREB-Binding Protein↗

PubMed1999

Triterpene antioxidants from ganoderma lucidum.

Ganoderma lucidum was studied for its antioxidative activity by bioassay guided isolation in conjunction with in vitro tests. The powdered crude drug was treated with boiling water and the aqueous extract (Ex1) was further separated to obtain terpene and polysaccharide fractions. The two fractions and Ex1 were screened for their antioxidative effect against pyrogallol induced erythrocyte membrane oxidation and Fe (II)-ascorbic acid induced lipid peroxidation. All tested samples showed antioxidative activities in a dose dependent manner and the terpene fraction was found to possess the highest effect compared with the others. Chemical isolation of the terpene fraction resulted in the detection of ganoderic acids A, B, C and D, lucidenic acid B and ganodermanontriol as major ingredients.

Animals↗

PubMed1999

An IgG antiprothrombin antibody enhances prothrombin binding to damaged endothelial cells and shortens plasma coagulation times.

OBJECTIVE: To test the hypothesis that some lupus anticoagulants are antiprothrombin antibodies, and that such antibodies enhance prothrombin binding to endothelial cells (EC) and thus promote clotting on the cell surface. METHODS: We generated a monoclonal antiprothrombin antibody (designated IS6) from a patient with primary antiphospholipid syndrome (APS). The antibody was analyzed for its binding properties, lupus anticoagulant activity, and pathophysiologic activity, using an EC-based plasma coagulation assay. RESULTS: IS6 is the first patient-derived monoclonal IgG antiprothrombin antibody. It bound to prothrombin with low affinity, reacted with 3 phospholipids (cardiolipin, phosphatidylethanolamine, and phosphatidylserine), and showed lupus anticoagulant activity. Moreover, IS6 enhanced the binding of prothrombin to damaged EC and shortened the EC-based plasma coagulation times. CONCLUSION: These findings suggest that IS6 may promote coagulation in areas of damaged EC in the host, and thus contribute to thrombosis in patients with APS.

Adult↗

PubMed1999

The human hyaloid system: cellular phenotypes and inter-relationships.

We have investigated the expression of leucocyte markers, phenotypic characteristics and cellular relationships of the normal human fetal hyaloid vasculature using immunohistochemistry, light and electron microscopy. Antibodies against von Willebrand Factor, alpha-smooth muscle actin, glial fibrillary acidic protein, vimentin, major histocompatibility complex classes-I and -II, CD45 (leucocyte-common antigen) and calcitonin gene-related peptide were used to identify the cellular constituents of the hyaloid vasculature in whole mounts. Additional morphological features were described at the ultrastructural level. Endothelial cells throughout the hyaloid system were immunoreactive to von Willebrand Factor and major histocompatibility complex class-I antibodies. Pericytes were immunoreactive to alpha-smooth muscle actin antibody; labeled cells were distributed along large branches of the hyaloid artery, vasa hyaloidea propria, tunica vasculosa lentis and pupillary membrane but no immunoreactivity was detected on small connecting capillaries. Vessel and non-vessel-associated hyalocytes on the hyaloid artery, vasa hyaloidea propria, tunica vasculosa lentis, pupillary membrane and vitreous were immunoreactive to major histocompatibility complex classes-I and -II, CD45 and calcitonin gene-related peptide antibodies. Anti-glial fibrillary acidic protein reactivity was detected on Bergmeister's papilla but not on the hyaloid artery. Cells immunoreactive for vimentin were present throughout the hyaloid vasculature including small connecting capillaries. Ultrastructural observations of the hyaloid vasculature revealed junctional complexes, including zonulae adherens, macula adherens and possible zonulae occludens, between adjacent endothelial cells. Fenestrae were not observed in the gestational ages included in the present study. The use of whole mounts in conjunction with specific antisera has provided novel immunohistochemical definitions of the structure and cellular constituents of the human hyaloid. The results indicate that hyalocytes are a heterogeneous population of leucocyte-lineage cells.

Astrocytes↗

PubMed1999

Changes in islet capillary angioarchitecture coincide with impaired B-cell function but not with insulin resistance in male Otsuka-Long-Evans-Tokushima fatty rats: dimorphism of the diabetic phenotype at an advanced age.

The Otsuka-Long-Evans-Tokushima fatty (OLETF) rat is a genetic model of spontaneous development of non-insulin-dependent diabetes mellitus (NIDDM) established as an inbred strain after 20 generations of selective breeding. Although they are thought to be genetically homogeneous, they show a dimorphism regarding the diabetic phenotype at an advanced age, with one remaining obese and modestly diabetic while the other becomes lean and overtly diabetic. To clarify the causes for this divergence, we examined the physical, biochemical, and histopathological features in rats at 50 weeks of age, including an analysis of islet angioarchitecture. Sixty-one of 85 male OLETF rats lost weight, while the remainder remained obese. Mean nonfasting plasma glucose in the lean group was 21.8+/-4.6 mmol/L, significantly higher versus the obese group (10.5+/-1.4 mmol/L) and the age-matched control Long-Evans-Tokushima-Otsuka (LETO) group (7.1+/-0.6 mmol/L). Morphological studies of the pancreas from the lean group showed enlarged multilobulated fibrotic islets with a paucity of B cells, whereas islets from the obese group appeared slightly enlarged and showed a relative abundance of B cells. The fine capillaries that form a network in the islets were extremely sparse in the lean group, resulting in a defective glomerular-like configuration, whereas those from the obese group were dense, forming a nearly typical glomerular-like configuration. Increased plasma insulin responses to oral and intravenous (i.v.) glucose and i.v. glucagon loads were nearly absent in the lean group, while they were evident in the obese group, although to a lesser extent compared with the LETO group. Mean insulin secretory output from the perfused pancreas in response to 11.1 mmol/L glucose in the lean group (3.5+/-2.2 pmol/20 min) was significantly lower versus the obese group (8.8+/-6.5 pmol/20 min) and LETO group (22.0+/-10.8 pmol/20 min). Similarly, pancreatic insulin content was significantly lower in the lean group (9.3+/-6.1 microg) versus the others (26.1+/-17.3 microg for obese and 41.1+/-24.8 microg for LETO). In vivo insulin-stimulated glucose uptake measured by a euglycemic clamp technique was significantly higher in the lean group compared with the obese group. These results demonstrate that the dimorphism regarding the diabetic phenotype in male OLETF rats at 50 weeks of age was due to differences in the number of islet B cells, which could be the result of a variation in the capacity for B-cell proliferation among male OLETF rats.

Aging↗

PubMed1999

Generation and characterization of a novel single-gene-encoded single-chain immunoglobulin molecule with antigen binding activity and effector functions.

Monoclonal antibody (MAb) CC49 is a murine IgG1 that reacts with tumor-associated glycoprotein (TAG)-72, a pancarcinoma antigen. Clinical trials using radiolabeled CC49 for diagnostic imaging have demonstrated specific localization of more than 90% of carcinomas. The feasibility of adopting in vivo gene inoculation methods for antibody-based immunotherapy requires introduction and expression of two genes, encoding immunoglobulin (Ig) heavy and light chains, in a single cell to generate a functional antibody. To circumvent the problems inherent in this approach, we have constructed a single-gene encoding a single-chain immunoglobulin (SCIg) that, unlike previously developed SCIgs, contains all IgG domains. To construct the novel SCIg, the carboxyl end of the constant region of the chimeric (c) CC49 kappa chain is joined, via a 30 residue Gly-Ser linker peptide, to the amino terminus of the CC49 heavy chain. To our knowledge, neither a linker peptide this long nor a linkage between the constant light (C(L)) and variable heavy domains has been reported previously. Transfectomas developed by introducing the expression construct of the amplifiable gene in dihydrofolate reductase-deficient Chinese hamster ovary (CHO dhfr-) cells secrete a 160 kDa homodimeric molecule, SCIgcCC49. The in vitro antigen binding properties of SCIgcCC49 are comparable to those of cCC49 and SCIgcCC49deltaC(H)1, a single-chain Ig deficient in constant heavy chain-1 (C(H)1) and C(L) domains. The antibody-dependent cellular cytotoxicity (ADCC) of SCIgcCC49 and cCC49 were also comparable. This single-gene approach for generating an immunoglobulin molecule may facilitate in vivo gene inoculation as well as ex vivo transfection of patients' cultured tumor-infiltrating lymphocytes for immunotherapy protocols for a variety of diseases, including cancer.

Animals↗

PubMed1999

Effects of ELF capacitively coupled weak electric fields on metabolism of 6B1 cells.

In this study, we adopted several methods of MTT colorimetry, DAPI fluorimetry and ELISA to study the effects of extremely low frequency (ELF) capacitively coupled electric fields (EFs) on the metabolism of 6B1 cells. The result shows that 50 mV cm(-1) ELF EF (10-100 Hz) has no significant effect on proliferation, DNA synthesis and activity of succinate dehydrogenase of 6B1 cells, indicating that the effect of ELF (10-100 Hz) EF on the metabolism of 6B1 cells is not obvious. However, 50 mV cm(-1), 50 Hz EF significantly promotes the HBs-Ab (Hepatitis B surface antibody) secretion of 6B1 cells, implying that under this situation, EF has some distinctive effect on the outerface of 6B1 cell membrane.

Cell Division↗

PubMed1999

Evaluation of the protective effects of Schisandra chinensis on Phase I drug metabolism using a CCl4 intoxication model.

To evaluate the potential activity of Schisandra chinensis in restoring hepatic drug metabolism in CCl4 damaged liver, antipyrine was employed as a probe for the possible effects of the herb on Phase I oxidative metabolism in rats. Schisandra lignan fraction (160 mg/kg) was given orally to male Sprague-Dawley rats (220-240 g) 30 min or 6 h before CCl4 intoxication (4 ml/kg, s.c.). Following a single oral dose of antipyrine (80 mg/kg) to the rats with damaged liver, the pharmacokinetics of antipyrine in whole blood were determined and levels of liver enzymes, e.g. SGPT, SGOT, and cytochrome P450 were measured. Pharmacokinetic parameters for antipyrine were estimated using noncompartmental analysis. Results indicated that CCl4 significantly increased the elimination half-life (t(1/2)) of antipyrine from 2.59 +/- 1.04 to 11.25 +/- 3.91 h (P < 0.001) and decreased its clearance (CL) from 65.94 to 10.84 ml/h as compared to control. Pretreatment with the Schisandra lignan fraction 30 min or 6 h before intoxication significantly (P < 0.001) improved antipyrine elimination by reducing its t(1/2) to 3.30 +/- 0.52 and 3.58 +/- 1.05 h, respectively. The corresponding improvements observed for CL, i.e. 49.06 +/- 21.75 ml/h (P < 0.01); 21.10 +/- 10.42 ml/h (P < 0.05), were also substantial. Moreover, normalization of SGPT, SGOT and P450 levels was observed with the two Schisandra pretreatment schedules. In conclusion, Schisandra lignans exhibited strong protective effect on Phase I oxidative metabolism in the liver damaged by CCl4. Furthermore, pretreatment of Schisandra 30 min before intoxication showed a more pronounced effect than that of the 6 h pretreatment. The current pharmacokinetic approach allowed the protective effects of Schisandra on oxidative drug metabolism in damaged liver to be systemically examined and will certainly help in the evaluation of hepato-protectants obtained from natural sources.

Animals↗