Risk factors, indicators and predictors of periodontal disease.
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Aging↗
Biomedical subjects
H L Wang
Publications and source records attributed to H L Wang.
5-HT1B receptor augmented 5-HT vasoconstrictor response of pulmonary artery in monocrotaline-induced pulmonary hypertensive rats.
AIM: To study the relationship between the vasoconstrictor effect to 5-hydroxytryptamine (5-HT) and the expression of 5-HT1B-and 5-HT1D)-receptors in pulmonary arteries (PA) from normal and pulmonary hypertensive (PHT) rats. METHODS: Monocrotaline (MCT)-treated rats were used as a model for chronic PHT. Concentration-response curves of 5-HT induced pulmonary vasoconstriction were established and semiquantitative RT-PCR was performed to identify mRNA expression of 5-HT1B- and 5-HT1D-receptors in rat PA. RESULTS: 5-HT induced vasoconstrictor response of PA from MCT rats was enhanced (Emax) 50 % +/- 20 % vs control 38 % +/- 21 %, P < 0.05). A significantly higher level of 5 -HT1B receptor mRNA expression was detected in PA from MCT rats. The ratio of the PCR products of 5-HT1B receptor gene to those of beta-actin gene was much higher in MCT rats than that in control rats (0.43 +/- 0.14 vs control 0.27 +/- 0.15, P < 0.05). CONCLUSION: 5-HT1B receptor is involved in pulmonary vasoconstriction and the enhanced level of 5-HT1B receptor mRNA expression is closely related to the augmentation of 5-HT induced pulmonary vasoconstriction in PHT rats.
Animals↗
Statistical versus clinical significance.
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Clinical Trials as Topic↗
[Expression, purification and identification of human matrix metalloproteinase-2].
The expression sequence of matrix metalloproteinase-2 (MMP-2) has been obtained by PCR amplifying, restriction enzyme cut and sequencing analysis demonstrate that the sequence is correct. The recombinant expression plasmid pPIC9/MMP-2 containing MMP-2 is constructed and transformed the yeast Pichia pastoris. Recombinant matrix metalloproteinase-2 protein was expressed in Pichia pastoris in great deal after induction by methanol. The purity of the recombinant MMP-2 filtrated through Sephacryl S-200 reached to electrophoresis purity. With the ability to degrade gelatin and IV type collagen, recombinant MMP-2 has the similar substrate specificity with natural MMP-2. The recombinant MMP-2 with 50 kD molecular weight is smaller than natural MMP-2, which suggested degradation occurred to it.
Chromatography, Agarose↗
[The effect of temperature on the enantiomeric resolutions on albumin and beta-cyclodextrin chiral stationary phases].
The effect of column temperature on enantiomeric resolutions of tryptophan, warfarin and ketoprofen was investigated on bovine and human serum albumin (BSA and HSA) stationary phases, which were synthesized with s-triazine as the activator. It was observed that the entropy change made a great contribution to the separation of those enantiomers on albumin chiral stationary phases. The column temperature for the maximal resolution of tryptophan on the BSA stationary phase prepared by this method was about 35 degrees C, which was not 24 degrees C as reported for the BSA stationary phase synthesized with glutaric dialdehyde as the activator. This results may come from the different conformation of the immobilized BSA and HSA due to the different coupling methods used. On the other hand, it was indicated that the resolution of enantiomers on beta-CD chiral stationary phase was mainly contributed from the change of enthalpy, which means the resolution of chiral solutes on albumin and beta-CD stationary phases has different thermodynamic behaviors.
Chromatography↗
[Pharmacokinetic studies of 20(R)-ginsenoside RG3 in human volunteers].
AIM: To study the pharmacokinetics of 20 (R)-ginsenoside Rg3 (GRg3) in human. METHODS: High-performance liquid chromatography-ultraviolet detection method was used in this study. RESULTS: The pharmacokinetics of GRg3 in 14 healthy volunteers were investigated. After a single oral dose of 3.2 mg.kg-1 in 8 male volunteers, the plasma concentration-time course fitted well to a two-compartment open model, with the following pharmacokinetic parameters: Tmax(0.66 +/- 0.10) h, Cmax(16 +/- 6) ng.mL-1, T1/2 alpha(0.46 +/- 0.12) h, T1/2 beta(4.9 +/- 1.1) h, T1/2(Ka)(0.28 +/- 0.04) h, AUC0-infinity(77 +/- 26) ng.mL-1.h. No kinetic analysis was made after an oral dose of 0.8 mg.kg-1 GRg3 in 6 other volunteers because of the low concentration, but a good correlation between Cmax and dosage of the two groups was found. CONCLUSION: The absorption of GRg3 was rapid in man, and its elimination was rapid after oral administration of ginsenoside Rg3. The pharmacokinetic results shows that it exhibited first order kinetic characteristics.
Adult↗
Point mutation associated with X-linked dominant Charcot-Marie-Tooth disease impairs the P2 promoter activity of human connexin-32 gene.
Many lines of evidence suggest that connexin-32 gap junction is involved in the exchange of information and metabolites in the peripheral nervous system. It has been shown that connexin-32 protein and mRNA are expressed in Schwann cells that function as myelinating cells of the peripheral nervous system. The physiological importance of connexin-32 gap junctions in regulating the normal function of myelinating Schwann cell is indicated by recent findings that X-linked dominant Charcot-Marie-Tooth disease, a hereditary peripheral neuropathy, is associated with the mutations of connexin-32 gene. Recently, we encountered a Taiwanese family affected with X-linked dominant Charcot-Marie-Tooth neuropathy. Therefore, we investigated the possible mutation in the coding and noncoding regions of the connexin-32 gene of affected members of this family. Our results suggest that a G-to-A transition at the position -215 (in relation to the transcription initiation site) of the nerve-specific P2 promoter region is associated with the pathogenesis of X-linked dominant Charcot-Marie-Tooth disease. Further experiments using the promoter assay indicate that G-to-A mutation at the position -215 greatly impairs the transcriptional activity of connexin-32 P2 promoter. These findings propose that a reduced expression of connexin-32 mRNA and protein in the myelin sheath could be responsible for the development of X-linked dominant Charcot-Marie-Tooth neuropathy.
Animals↗
Breast cancer growth inhibition by delivery of the MDGI-derived peptide P108.
Mammary derived growth inhibitor (MDGI) is a member of the family of cytoplasmic fatty acid binding proteins (FABPs), which bind hydrophobic ligands such as fatty acids, retinoids, eicosanoids and prostaglandines. MDGI and an 11 amino acid MDGI-derived conserved C-terminal peptide (P108) inhibits growth of normal mammary epithelial cells in tissue and organ culture, but fails to inhibit proliferation of many breast cancer cell lines in vitro. Here, the effects of peptide P108 on tumor growth of MCF-7, MDA-MB468 and MDA-MB231 human breast cancer cell lines in nude mice were tested. To deliver P108 into tumors, a novel peptide production system was applied for expression and secretion of small bioactive peptides in mammalian cells. Functional differentiation was observed in MCF-7 and MDA-MB468 cells upon P108 expression. In addition, EGF-dependent colony formation in soft agar by MDA-MB468 cells was inhibited by secreted P108. Tumor growth in athymic nude mice was suppressed in all three cell lines tested. Furthermore, P108 expressed by MCF-7/P108 cells caused paracrine tumor growth inhibition of MDA-MB231 cells. These results indicate that breast cancer inhibition by P108 is independent of binding to hydrophobic ligands and is perhaps mediated by interference with EGF-dependent signaling pathways.
Amino Acid Sequence↗
Hepatitis C virus core protein-induced loss of LZIP function correlates with cellular transformation.
Hepatitis C virus (HCV) is the major etiological agent of blood-borne non-A non-B hepatitis and a leading cause of liver cirrhosis and hepatocellular carcinoma worldwide. HCV core protein is a multifunctional protein with regulatory functions in cellular transcription and virus-induced transformation and pathogenesis. Here we report on the identification of a bZIP nuclear transcription protein as an HCV core cofactor for transformation. This bZIP factor, designated LZIP, activates CRE-dependent transcription and regulates cell proliferation. Loss of LZIP function in NIH 3T3 cells triggers morphological transformation and anchorage-independent growth. We show that HCV core protein aberrantly sequesters LZIP in the cytoplasm, inactivates LZIP function and potentiates cellular transformation. Our findings suggest that LZIP might serve a novel cellular tumor suppressor function that is targeted by the HCV core.
3T3 Cells↗
A cluster of Ser/Thr residues at the C-terminus of mu-opioid receptor is required for G protein-coupled receptor kinase 2-mediated desensitization.
To investigate the functional role of G protein-coupled receptor kinases (GRK) in homologous desensitization of the mu-opioid receptor, human embryonic kidney (HEK) 293 cells, which express a significant level of GRK2, were stably transfected with the cDNA encoding the rat mu-opioid receptor. Wild-type mu-opioid receptors developed homologous desensitization after 30 min pretreatment with DAMGO ([D-Ala2,N-methyl-Phe4,Gly-ol5]enkephalin), a specific mu-opioid receptor agonist. The ability of mu-opioid receptors to develop homologous desensitization was greatly impaired following the transfection of a cDNA fragment encoding the GRK2(495-689) polypeptide, which is believed to block Gbetagamma-mediated transduction events including the membrane translocation and activation of GRK2. The mu(Cdelta45) receptor, a deletion mutant that lacks 45 C-terminal amino acids, failed to exhibit homologous desensitization after 30 min pretreatment of DAMGO. The mu(Cdelta41) receptor, which differs from the mu(Cdelta45) receptor by having four more Ser/Thr residues (Thr354Ser355Ser356Thr357), developed GRK2-mediated desensitization. These results suggest that homologous desensitization of rat mu-opioid receptors results from the activation of GRK2 and that a cluster of Ser/Thr residues (Thr354Ser355Ser356Thr357) at the intracellular carboxyl tail plays an important role in GRK2-mediated mu-opioid receptor desensitization.
Analgesics, Opioid↗
Effects of tetrandrine on growth factor-induced DNA synthesis and proliferative response of rat pulmonary artery smooth muscle cells.
The objective of the present study was to investigate the effect of tetrandrine (a plant alkaloid isolated from Stephenia tetrandra) on growth factor-induced DNA synthesis and proliferative responses of rat pulmonary artery smooth muscle cells. Male rat and bovine pulmonary artery smooth muscle cells (PASMC) were cultured in Medium 199 containing FBS (10%). DNA synthesis was monitored from [(3)H]-thymidine uptake and cell proliferation by direct cell counting. In the present study FBS (1% v/v) caused a small increase in DNA synthesis above basal levels in rat and bovine PASMC (6% and 11% respectively). Platelet-derived growth factor (PDGF, 50 ng/ml), fibroblast growth factor (FGF, 50 ng/ml) or interleukin-1alpha (IL-1alpha, 100 pg/ml) alone increased rat PASMC proliferation (69-85%) and DNA synthesis above basal levels (76-92%). The addition of these growth factors in combination with FBS (1%) resulted in higher increases in DNA synthesis above basal levels (rat PASMC:PDGF, 465%; FGF, 421%; IL-1alpha, 406%; bovine PASMC:PDGF, 279%). Tetrandrine (10(-5) M) inhibited FBS (10%)-induced rat PASMC proliferation (90.5%) and DNA synthesis (89.0%). Tetrandrine significantly inhibited cell proliferation (86.5-98.5%) and DNA synthesis (79.9-89.0%) induced by FBS (1%) in combination with one of the following mitogens; PDGF (50 ng/ml), FGF (50 ng/ml), IL-1alpha (100 pg/ml). The inhibitory effects of tetrandrine were observed between 10(-6) and 10(-5)M and PASMC viability was not affected by tetrandrine below 3x10(-5) m. In summary, these results suggest that tetrandrine can exert anti-proliferative effects against a range of mitogenic stimuli for vascular smooth muscle cells in vitro. Such effects may contribute to the inhibitory effect of tetrandrine on pulmonary vascular remodelling associated with pulmonary hypertension.
Alkaloids↗
Supplemental systemic oxygen support using an intestinal intraluminal membrane oxygenator.
An intraluminal membrane oxygenator (IMO) prototype was surgically inserted in the ileum and evaluated as a method of supporting systemic oxygenation in an acutely hypoxemic porcine model. Animals were assigned randomly to the test (n = 12) or the control (n = 8) groups, which underwent identical protocols with the exception of the O2 flow in the IMO device, which was shut off in the control group. In each case, hypoxia was induced by a reduction in the inspired oxygen fraction (FiO2) to 0.14. A highly significant improvement (p < 0.005) in arterial and venous O2 content and lower arteriovenous O2 difference (p < 0.05), cardiac output, and hemoglobin (p < 0.005) were found in the test group during hypoxia. The results show that it is possible to meet a physiologically significant portion of the body's O2 demands via the intestine during respiratory hypoxia and suggests that similar devices may be of significant potential value as a supplemental oxygenation device in cases of respiratory distress.
Analysis of Variance↗
Fundamental gating mechanism of nicotinic receptor channel revealed by mutation causing a congenital myasthenic syndrome.
We describe the genetic and kinetic defects in a congenital myasthenic syndrome due to the mutation epsilonA411P in the amphipathic helix of the acetylcholine receptor (AChR) epsilon subunit. Myasthenic patients from three unrelated families are either homozygous for epsilonA411P or are heterozygous and harbor a null mutation in the second epsilon allele, indicating that epsilonA411P is recessive. We expressed human AChRs containing wild-type or A411P epsilon subunits in 293HEK cells, recorded single channel currents at high bandwidth, and determined microscopic rate constants for individual channels using hidden Markov modeling. For individual wild-type and mutant channels, each rate constant distributes as a Gaussian function, but the spread in the distributions for channel opening and closing rate constants is greatly expanded by epsilonA411P. Prolines engineered into positions flanking residue 411 of the epsilon subunit greatly increase the range of activation kinetics similar to epsilonA411P, whereas prolines engineered into positions equivalent to epsilonA411 in beta and delta subunits are without effect. Thus, the amphipathic helix of the epsilon subunit stabilizes the channel, minimizing the number and range of kinetic modes accessible to individual AChRs. The findings suggest that analogous stabilizing structures are present in other ion channels, and possibly allosteric proteins in general, and that they evolved to maintain uniformity of activation episodes. The findings further suggest that the fundamental gating mechanism of the AChR channel can be explained by a corrugated energy landscape superimposed on a steeply sloped energy well.
Cell Line↗
Osmotic stress-induced changes of sucrose metabolism in cultured sweet potato cells.
The intra- and extracellular sugar contents, the activities of sucrose-metabolizing enzymes, and the metabolism of [U-(14)C] glucose in a pulse-chase experiment were compared between the normal and osmotically stressed (by 0.6 M sorbitol) sweet potato (Ipomoea batatas) suspension cells. The stress enhanced the levels of sucrose and sucrose phosphate synthase (SPS) activity. Northern blot analysis also showed that prolonged osmotic stress enhanced the SPS gene expression at the transcriptional level. Stressed cells also had higher activities of sucrose cleaving enzymes, such as alkaline invertase and sucrose synthase. The (14)C-sucrose isolated from normal and stressed cells had (14)C-fructose and (14)C-glucose ratios of 0.68 and 1, respectively. These data suggest the continual cycling of degradation and synthesis of sucrose in both types of cells. Among the enzymes used in constructing such futile cycling, besides invertase and SPS, sucrose synthase (SS) should be involved in normal cells, but not in stressed ones. It is apparent that the osmotic stress caused a significant change in the pattern of sucrose metabolism.
Cells, Cultured↗
Corticotropin-releasing factor produces a protein synthesis--dependent long-lasting potentiation in dentate gyrus neurons.
Corticotropin-releasing factor (CRF) was shown to produce a long-lasting potentiation of synaptic efficacy in dentate gyrus neurons of the rat hippocampus in vivo. This potentiation was shown to share some similarities with tetanization-induced long-term potentiation (LTP). In the present study, we further examined the mechanism underlying CRF-induced long-lasting potentiation in rat hippocampus in vivo. Results indicated that the RNA synthesis inhibitor actinomycin-D, at a concentration that did not change basal synaptic transmission alone (5 microgram), significantly decreased CRF-induced potentiation. Similarly, the protein synthesis inhibitor emetine, at a concentration that did not affect hippocampal synaptic transmission alone (5 microgram), also markedly inhibited CRF-induced potentiation. These results suggest that like the late phase of LTP, CRF-induced long-lasting potentiation also critically depend on protein synthesis. Further, prior maximum excitation of dentate gyrus neurons with tetanization occluded further potentiation of these neurons produced by CRF and vise versa. Moreover, quantitative reverse transcription-polymerase chain reaction analysis revealed that CRF mRNA level in the dentate gyrus was significantly increased 1 h after LTP recording. Together with our previous findings that CRF antagonist dose-dependently diminishes tetanization-induced LTP, these results suggest that both CRF-induced long-lasting potentiation and tetanization-induced LTP require protein synthesis and that CRF neurons are possibly involved in the neural circuits underlying LTP.
Animals↗
Efficient diagnosis of dengue infections using patients' peripheral blood leukocytes and serum/plasma.
OBJECTIVE: Dengue fever has been one of the most important health problems in Taiwan since a large outbreak during 1987 and 1988. It is critically necessary to have a diagnostic approach that can detect early infections in an outbreak or even find infections existing in silent transmission of the disease. METHODS: To develop an efficient diagnostic protocol, 105 plasma/serum and 35 peripheral blood leukocyte (PBL) specimens from the 1994 outbreak in southern Taiwan were collected for assessment by various diagnostic techniques in this study. RESULTS: In acute blood samples, dengue viruses were isolated from 19.4% (14/72) and 33.3% (14/42) of reported and confirmed cases, respectively. Viral RNA in serum/plasma was detected from 20.0% (12/60) of acute samples, which was significantly higher than that from convalescent samples (3/44; 6.8%). However, viral RNA in PBLs, detected by reverse transcription polymerase chain reaction (PBL-RT-PCR), could be observed in 73.2% (19/26) and 66.7% (6/9) of acute and convalescent samples, respectively. The persistence of dengue viruses in PBLs was also evidenced by the presence of viral antigens in 42.9% (4/7) of confirmed convalescent samples by the immunofluorescence antibody test. In addition, IgM antibodies were detected in 43.8% (46/105) of reported cases and 85.2% (46/54) of confirmed cases by the IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA). CONCLUSIONS: Although IgM antibody detection achieved the highest detection rate among techniques assessed in this study, no individual test can actually reach full efficiency for early diagnosis of dengue infections. Here, we propose a protocol which applies MAC-ELISA and PBL-RT-PCR in sequence, by which 22 confirmed cases were definitely proved as dengue positive. High levels of both sensitivity and specificity were shown in this protocol.
Antibodies, Viral↗
The effect of locally delivered controlled-release doxycycline or scaling and root planing on periodontal maintenance patients over 9 months.
BACKGROUND: This research report evaluates clinical changes resulting from local delivery of doxycycline hyclate (DH) or traditional scaling and root planing (SRP) in a group of patients undergoing supportive periodontal therapy (SPT). METHODS: In all, 141 patients received either DH (67) or SRP (74) treatment in sites > or =5 mm on one-half of their dentition at baseline and month 4. RESULTS: Clinical results were determined at month 9. Baseline mean probing depth recordings were similar between the two groups (DH = 5.9 mm; SRP = 5.9 mm). Mean month 9 results showed similar clinical results for attachment level gain (DH 0.7 mm; SRP 0.8 mm) and probing depth reduction (DH 1.3 mm; SRP 1.1 mm). Percentage of sites showing > or =2 mm attachment level gain at month 9 was 24.7% in the DH group and 21.2% in the SRP group. Thirty-nine percent (39%) of DH sites and 38% of SRP sites showed > or =2 mm probing depth reduction. When treated sides of the dentition were compared to untreated sides, DH showed a difference in disease activity (> or =2 mm attachment loss) from 19.3% (untreated) to 7.2% (treated); and SRP from 14.3% (untreated) to 8.1% (treated). CONCLUSIONS: Results show that both DH without concomitant mechanical instrumentation and SRP were equally effective as SPT in this patient group over the 9-month study period.
Administration, Topical↗
Using absorbable collagen membranes for guided tissue regeneration, guided bone regeneration, and to treat gingival recession.
This article reviews the role of barrier membranes in guided tissue regeneration (GTR) and guided bone regeneration (GBR), including the advantages of using absorbable barrier membranes in GTR and GBR and the unique properties of collagen membranes. The indications and contraindications for using collagen membranes for these procedures are examined, and successful cases are presented. Finally, the role of collagen membranes in the future of regenerative therapy is considered.
Absorbable Implants↗