Biomedical subjects

Y M Wu

Publications and source records attributed to Y M Wu.

At least 37 records · Page 2Linked to original sources

PubMed1999

[Bradykinin inhibits carotid sinus baroreflex in anesthetized rats].

The effects of bradykinin (BK) on the carotid baroreflex were examined in 36 anesthetized rats with isolated carotid sinus perfusion. The results obtained are as follows. (1) By perfusing the isolated carotid sinus with BK (1.0 mumol/L), the functional curve of baroreflex was shifted to the right and upward, its peak slope (PS) decreasing from 0.44 +/- 0.14 to 0.31 +/- 0.01 kPa (P < 0.01) and the reflex decrease in mean arterial pressure (RD) was lowered from 6.85 +/- 0.18 to 4.46 +/- 0.16 kPa (P < 0.05), while the threshold pressure (TP), equilibrium pressure (EP) and saturation pressure (SP) were significantly enhanced from 7.76 +/- 0.20 to 10.04 +/- 0.09 kPa (P < 0.001), 12.72 +/- 0.29 to 13.74 +/- 0.31 kPa (P < 0.05) and 23.28 +/- 0.24 to 25.31 +/- 0.20 kPa (P < 0.01), respectively. Among the functional parameters of carotid baroreflex, the changes in RD, PS and TP induced by BK were dose-dependent. (2) By pretreatment with indomethacin (10 mumol/L), an inhibitor of prostaglandin synthesis, the above-mentioned effects of BK on carotid baroreflex were not affected. (3) Preperfusion with an inhibitor of NO synthase L-NAME (100 mumol/L) could completely eliminate the effects of BK. (4) Pretreatment with angiotensin-converting enzyme inhibitor captopril (20 mumol/L) could potentiate the effects of BK. Taken together, it is indicated that BK may cause vascular endothelium to release NO, thereby inhibiting the carotid baroreflex.

Animals↗

PubMed1998

Molecular and electrophysiological characterizations of fGluR3 alpha, an ionotropic glutamate receptor subunit of a teleost fish.

Here we report the cloning and functional analysis of a cDNA encoding a functional glutamate receptor subunit of Oreochromis sp., a freshwater teleost fish. The deduced amino acid sequence of this cDNA clone, fGluR3 alpha, displays the highest sequence identity to that of the mammalian GluR3 subunit. Results of quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) analysis indicated that the expression level of fGluR3 alpha in the cerebellum was much less than that in the telencephalon and optical lobe. Similar to its mammalian counterpart, variants of fGluR3 alpha were created by alternative splicing and RNA editing at the R/G site. The channel properties of homomeric fGluR3 alpha expressed in Xenopus oocytes were similar to those of the mammalian alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-preferring receptors. The rank order of agonist potency of the expressed fGluR3 alpha is AMPA > or = glutamate > or = quisqualate > domoate > or = kainate. This is the first functional glutamate receptor of teleost fish being demonstrated to be sensitive to AMPA. Furthermore, this study suggested a strong functional conservation of AMPA-preferring receptors in vertebrates.

Amino Acid Sequence↗

PubMed1998

Role of neuropeptide Y in cold stress-induced hypertension.

Chronic cold stress (4 degrees C) produced a sustained increase in mean arterial pressure in both normotensive and borderline hypertensive rats (BHR). The high blood pressure in BHRs was significantly reversed by a neuropeptide Y (NPY) Y1 receptor antagonist suggesting that NPY is involved in mediating stress-induced hypertension. Corresponding increases in adrenal NPY messenger RNA and NPY immunoreactivity were found during the stress; furthermore, chronic cold stress also potentiated the pressor response of rats to a subsequent acute stress test in which NPY has been shown to play a role. These results suggest that chronic cold stress-induced hypertension is mediated by elevated NPY release and vascular tone as a result of increased NPY gene expression and storage.

Adrenal Glands↗

PubMed1998

Measurement of prostaglandin E2 and leukotriene B4 in the gingival crevicular fluid.

UNLABELLED: The arachidonic acid metabolites prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) are inflammatory mediators which are likely to be involved in the pathogenesis of periodontal disease. PGE2 mediates vasodilatation, increases vascular permeability, enhances pain perception by bradykinin and histamine, alters connective tissue metabolism and enhances osteoclastic bone resorption. LTB4 causes the accumulation of inflammatory cells in the inflamed sites, and degranulation of polymorphonuclear leukocytes. OBJECTIVE: To measure gingival crevicular fluid (GCF) levels of PGE2, LTB4 and periodontal health. METHODS: The periodontal condition of 24 subjects was evaluated on the basis of plaque index, gingival index, probing depth, and attachment level. GCF samples were collected from one or two site(s) of each sextant per subject and the volume was measured using Periotron 6000. Samples were then assayed for PGE2 and LTB4 using a competitive enzyme immunoassay. Mean PGE2 and LTB4 levels were determined for each subject and group means compared. RESULTS: Significant differences in the levels of PGE2 and LTB4 were found between patients with periodontitis, and non-periodontitis individuals (P < 0.001). The PGE2/LTB4 levels were positively correlated with the clinical parameters (P < 0.01) and reduced markedly after phase 1 of the periodontal treatment (P < 0.01). The total amount and concentration (ng ml-1) of LTB4 was positively correlated with the gingival index (P < 0.01). CONCLUSIONS: These results indicate that the levels of PGE2 correlated with the severity of the periodontal status, and the levels of LTB4 correlated with gingival inflammation. Thus, our data suggest that the total amounts of PGE2/LTB4 may be good indicators for periodontal inflammation.

Adult↗

PubMed1998

[The influence of school staffs willingness and dental health education intervention on the oral hygiene status of the elementary school children].

The main purpose of this study was to understand the influence of school administrator's and teacher's participation in oral hygiene promotion, and dental health education intervention on the oral hygiene status of the elementary school children. Questionnaires designed to evaluate the school staff's willingness to emphasize and proceed the oral hygiene programs were answered by the school administrators (principals, deans of pupils' affair, chiefs of physical education and hygiene departments, and nurses) in 75 public elementary schools of the Kaohsiung City, Taiwan. Two of the most, and of the least cooperative schools were randomly selected. The fifth grade teachers of those four schools were asked to answer the questionnaires. Pupils of the two classes whose teachers who had the greatest and the least willingness to participate were selected for further investigation. Pupils were asked to answer questionnaires, receive oral examinations and tooth-brushing instructions every other two weeks for a total of two times. The results were as follows: 1. Before active oral hygiene instruction, there is no significant difference in plaque scores among groups. However, DMFT scores are influenced by school administrators. 2. The oral hygiene education intervention actually significantly improved the school children's plaque scores. 3. The cooperation of school administrators and teachers has a positive influence on keeping (forming) school children's good oral hygiene habits. Furthermore, the influence from school administrators is more than that from teachers. 4. School children's knowledge of oral hygiene is influenced by school' administrators and teachers while teachers' attitude of oral hygiene is influenced by school administrators.

Child↗

PubMed1997

Elevated neuropeptide Y gene expression and release during hypoglycemic stress.

Our previous studies show that neuropeptide Y (NPY) is involved in mediating sympathetic nerve stimulation-induced vasoconstriction. Insulin hypoglycemia is known to produce increased sympathetic output and elevated arterial pressure. The present study examined the role of NPY in the hypertensive response to insulin by examining the effects of insulin on NPY gene expression, tissue content and release. Subcutaneous injection of insulin produced an immediate increase in plasma NPY immunoreactivity (NPYir) and delayed increases in adrenal and neuronal NPY mRNA and adrenal NPYir in rats. These results suggest that NPY may play a role in insulin-induced hypertension.

Adrenal Medulla↗

PubMed1997

(-)-Stepholidine enhances K+ depolarization-induced activation of synaptosomal tyrosine 3-monooxygenase from rat striatum.

AIM: To study the mechanism of K+ depolarization-induced activation of synaptosomal tyrosine 3-monooxygenase (TM) in rat striatum and the effect of (-)-stepholidine (SPD) on this activation. METHODS: The TM was assayed for DOPA by HPLC-ECD; the activities of Ca2+/calmodulin (CaM)-dependent protein kinase (PK II) and Ca2+/phosphoinositide-dependent protein kinase (PKC) were assayed using histidine as substrate. RESULTS: The incubation of striatal synaptosomes in K(+)-riched (60 mmol.L-1) medium resulted in a marked activation of TM. PKC inhibitor polymyxin B (PMB) completely blocked the activation of K+ 60 mmol.L-1 on TM. Selective D2 receptor agonist quinpirole (QP), Ca2+ removal from incubation medium and CaM antagonist W7 failed to affect the activation. However, SPD enhanced the activation of K+ 60 mmol.L-1 on TM. Meanwhile, the incubation in K+ 60 mmol.L-1 also activated PKC. Neither QP nor SPD affected K+ depolarization-induced activation of PKC. CONCLUSION: The activation of K+ depolarization on synaptosomal TM is enhanced by SPD and this activation is mediated by PKC rather than by PK II.

Animals↗

PubMed1997

Periodontal manifestations and treatment of Sturge-Weber syndrome--report of two cases.

Encephalotrigeminal angiomatosis (Sturge-Weber syndrome) is a rather uncommon congenital condition characterized by the combination of venous angioma of the leptomeninges over the cerebral cortex with ipsilateral angiomatous lesions of the face and sometimes, the skull, jaws and oral soft tissues. Two patients came to the Kaohsiung Medical College Hospital's dental clinic with complaints of localized gingival enlargement or tumor-like swelling. Based on the presence of facial nevus flammeus, examinations of angiography, radiological evidence of calcific densities, and ipsilaterally intraoral vascular hyperplasia in the lip, cheek and gingiva, encephalotrigeminal angiomatosis was diagnosed. Dental management included plaque control instructions, scaling, root planing and periodontal surgery. Recurrence of gingival enlargement in both cases was noted, so periodontal surgery was performed a second time. Close follow up and complete plaque control have kept the periodontal condition fairly well under control in these two cases. We introduce the oral manifestations and the experience of treatments in these two cases.

Adolescent↗

PubMed1997

Collagen synthesis in idiopathic and dilantin-induced gingival fibromatosis.

Gingival fibromatosis is an uncommon but benign oral disease which causes progressive and non-hemorrhagic enlargement of the gingiva. There are two types of gingival fibromatosis: idiopathic gingival fibromatosis (GF), which is of unknown cause and may be associated with hereditary factors, and drug-induced gingival fibromatosis which is caused primarily by phenytoin intake. In cases of gingival fibromatosis, either the teeth are delayed in emergence or most of the crowns are embedded in the soft tissue even after full eruption. The objective of this study was to examine the basis of excess collagen formation in the two types of gingival fibromatosis in four patients admitted to the dental clinic at Kaohsiung Medical College Hospital, Kaohsiung, Taiwan. There were two male patients, aged ten (Case 1) and sixteen (Case 2), with idiopathic gingival fibromatosis and hypertrichosis, and two female patients, aged sixteen (Case 3) and eleven (Case 4), with Dilantin-induced gingival hyperplasia (DGH). Cultures of gingival fibroblast were established either from clinically excised hyperplastic tissues or from pre-orthodontic surgical normal gingiva. The synthesis of collagen and levels of prolyl hydroxylase, a key enzyme in collagen synthesis, were examined in the healthy and affected fibroblasts. Our studies showed that after two days in culture, fibroblasts from all four patients multiplied faster than healthy gingival fibroblasts, though the amount of DNA and protein per cell remained unchanged. In addition, all cultures (except Case 1) had a 2- to 3- fold increase of prolyl hydroxylase activity over that of the controls. As in the cases of prolyl hydroxylase activity, Case 1 did not show any change in collagen synthesis when compared to the control. However, Cases 2, 3, and 4 showed appreciable collagen increases in the cell and medium: 61% and 60% for Case 2; 16% and 36% for Case 3; and 21% and 80.7% for Case 4 respectively.

Adolescent↗

PubMed1997

Liposomes-coated hydroxyapatite and tricalcium phosphate implanted in the mandibular bony defect of miniature swine.

Hydroxyapatite and tricalcium phosphate have been used as bone implants for some period of time. Now unfortunately, these materials have failed to become the nucleation sites for bone regeneration. We hypothesized that coating hydroxyapatite and tricalcium phosphate with negatively charged liposomes may improve the nucleation process for new bone formation. The present study was designed to test this hypothesis. Experiments were carried out in 15 miniature swines' mandibular angle with artificial bony defects. In each of the swine, the bony defects on one side were implanted with either liposomes coated with hydroxyapatite or liposomes coated with tricalcium phosphate, while the other side served as control. At the end of the third and sixth weeks following the operation, we observed result, took histology and radiographs of the operated area. The results showed that liposomes-coated materials were biocompatible and their clinical endpoint was enhanced. At the end of the third week, the implant material was surrounded by dense connective tissues. At the end of the sixth week, there were new bone formations near the implanted material. In addition, liposomes which were immobilized in agarose gel and implanted in the defects showed new bony bridge formation. These observations suggest that liposomes have the ability in promoting repair of osseous deficiencies.

Alveolar Process↗

PubMed1997

[Multiple myeloma with oral manifestations--report of two cases].

Multiple myeloma is a neoplastic disorder of bone that originates from cells of bone marrow. It is most commonly seen within the age range of 50-80 years, cases under the age of 40 being rare. Men are affected more frequently than are women. Bone pain is the cardinal clinical symptom in multiple myeloma. Because of the destruction of bone, pathologic fracture is fairly common. In the oral manifestations, the mandible is involved far more frequently than the maxilla, especially the most active hematopoietic areas-the remus, angle and molar region of the mandible. Other signs and symptoms of jaw involvement include swelling, pain, and increased tooth mobility. Extraosseous lesions may result in paresthesia of soft tissue and gingival enlargement with bleeding tendency. Roentgenographic examination will usually reveal numerous punched-out lesions in a variety of bones. In addition, blood examination will reveal hyperglobulinemia and Bence-Jones protein may be present in the urine of myeloma patients. The histological features of myeloma are closely packed cells resembling plasma cells. Case 1 in this report is a 64-year-old female, who has been diagnosed as having multiple myeloma (IgG, lambda). She was referred to our hospital because of gingival swelling, bleeding and pain. Case 2 is a 60-year-old female suffering from spontaneous gingival bleeding. After blood, urine examination and bone marrow biopsy, multiple myeloma was diagnosed (IgG, lambda). This paper reports the clinical manifestations and treatment courses of these two cases, and the concerns of treatment of multiple myeloma are also discussed.

Female↗

PubMed1996

Circadian variation of tacrolimus disposition in liver allograft recipients.

The aim of this study was to characterize the circadian variation of oral tacrolimus disposition in 8 stable liver allograft recipients. In the steady state, a total of 23 blood samples was taken before and after tacrolimus administration during a 24-hr period and the pharmacokinetic parameters were compared. The area under the curve (AUC) of tacrolimus after the morning dose was significantly larger than after the evening dose (211+/-43 ng x hr/ml [morning] vs. 179+/-45 ng x hr/ml [evening], P=0.02). The time to peak (Tmax) was significantly shorter after the morning dose than after the evening dose (1.6+/-0.7 hr [morning] vs. 2.9+/-0.6 hr [evening], P=0.002). The peak (Cmax) was significantly higher after the morning dose than after the evening dose (32.2+/-10.2 ng/ml [morning] vs. 19.1+/-4.3 ng/ml [evening], P=0.003). However, the trough (Cmin) was not significantly different between the morning dose and the evening dose (13.1+/-3.9 ng/ml [morning] vs. 13.3+/-4.4 ng/ml [evening], P=0.4). This study demonstrated that tacrolimus disposition in liver transplant patients was determined by administration time.

Adult↗

PubMed1996

Determination of relative abundance of splicing variants of Oreochromis glutamate receptors by quantitative reverse-transcriptase PCR.

In this study, the relative abundance of splicing variants of Oreochromis non-NMDA subtype glutamate receptors was studied by quantitative reverse-transcriptase PCR (RT-PCR). The relative expression level between the flip and flop transcripts of fGluR2 alpha determined by quantitative RT-PCR is apparently much higher than that estimated by sequence analysis of the cloned RT-PCR products. Control studies were performed to demonstrate the accuracy of the application of quantitative RT-PCR analysis in studying the relative abundance between the flip and flop transcripts of glutamate receptors.

Alternative Splicing↗

PubMed1996

Characterization of two fish glutamate receptor cDNA molecules: absence of RNA editing at the Q/R site.

Two cDNA clones encoding putative ionotropic glutamate receptor subunits were isolated from a brain cDNA library of a freshwater fish, Oreochromis sp. The deduced amino acid sequences of these two cDNAs, fGluR2 alpha and fGluR2 beta, display the highest sequence identity (85%) to that of the rat GluR2 (AMPA receptor subunit) and they contain an arginine codon at the Q/R editing site of the TM2 segment. Genomic sequence analysis of the exons encoding the TM2 reveals the presence of an arginine codon at the Q/R site, suggesting that the RNA editing mechanism acting in the mammalian GluR2 does not operate at the homologous site in these two fish genes. In contrast to the absence of RNA editing at the Q/R site, transcripts of fGluR2 alpha and fGluR2 beta are subjected to RNA editing at a second site, the R/G site. A splicing variant of fGluR2 alpha, fGluR2 alpha-c, with a shorter C-terminal sequence was found; however, no C-terminal splicing variant of fGluR2 beta was detected in the mature fish. Similar to the mammalian AMPA receptor, variants created by the alternate choice of flip and flop modules were found among transcripts of fGluR2 alpha-c and fGluR2 beta. The amino acid sequences of flip and flop modules of fGluR2 beta are identical to that of the rat GluR2, whereas the amino acid sequences of the flip and flop modules of fGluR2 alpha-c differ from the invariant consensus sequences of the rat AMPA receptor subunits.

Alternative Splicing↗

PubMed1996

Molecular analysis of cDNA molecules encoding glutamate receptor subunits, fGluR1 alpha and fGluR1 beta, of Oreochromis sp.

In this study, we isolated two cDNA molecules encoding putative glutamate receptor subunits, fGluR1 alpha and fGluR1 beta, from an Oreochromis sp. brain cDNA library by hybridizing with the glutamate receptor cDNA, fGluR2 beta, of the same fish. The deduced amino acid sequence of the fGluR1 alpha consists of 908 residues with an 18-residue signal peptide and displays a sequence identity of 74% to the amino acid sequence of rat GluR1 subunit. Northern blotting indicates that the expression level of fGluR1 alpha in telencephalon is higher than that in optic tectum and cerebellum in adult fish brain. Reverse-transcriptase polymerase chain reaction and genomic analyses reveal the presence of variants created by alternative splicing at the flip-flop module and the carboxyl terminus of fGluR1 alpha transcripts. The amino acid sequence of fGluR1 alpha is unique in that it contains a glutamine-rich sequence inserted at the loop 1 (L1) between transmembrane domains 1 and 2. A second incomplete cDNA clone, designated fGluR1 beta, coding for a polypeptide showing sequence identity to the rat GluR1 and fGluR1 alpha was isolated from the same library. Insertion of a serine- and glutamine-rich sequence at the L1 was also detected in the translated sequence of fGluR1 beta.

Amino Acid Sequence↗

PubMed1996

Intrahepatic arterial chemoembolization for hepatocellular carcinoma and metastatic neuroendocrine tumors in the era of liver transplantation.

Surgical resection has been the standard approach for primary and metastatic liver tumors. Long-term survival, however, is limited because of recurrence or hepatic decompensation. Failure of chemotherapeutic regimens or liver transplantation (OLT) to prevent recurrence has resulted in the need for multimodality therapies. We report our experience with preoperative hepatic arterial chemoembolization (CET) followed by OLT in highly select patients. Over a 33-month period, 23 of 41 patients (56%) referred with primary (n = 16) or metastatic neuroendocrine (n = 7) liver tumors met eligibility requirements. Despite mild, self-limited chemical hepatitis, CET was well tolerated in all but three elderly patients who succumbed to liver failure. Four of five patients ultimately received OLT. Three are alive and free of disease at a mean followup of 17 months, one died of recurrent hepatocellular carcinoma, and one (NET) remains well at 33 months with elevated glucagon levels but no measurable disease. All NET patients are alive with resolution of hormonal symptoms. Four of five noncirrhotic patients died of disease, and one has progressive tumor growth. Although OLT following CET achieves superior survival, its application is limited to a minority of patients with such tumors. Careful pretreatment staging and patient selection combined with caution in the use of CET in elderly cirrhotic patients is critical to the success of such therapies.

Adult↗

PubMed1996

[Evaluation of the biosynthesis of mono-HETES and leukotrienes in diseased periodontal tissues].

Many arachidonic metabolites have been shown to have marked potent biological effects in animals. The cyclooxygenase and lipoxygenase products of arachidonate metabolism are known to play a key role in the development of inflammatory symptoms and signs. Reports published during past decades indicate that cyclooxygenase products of arachidonic acid metabolism are present in much higher concentrations in inflamed than in healthy periodontal tissues. Since information about the role of lipoxygenase products of arachidonic acid metabolism in human periodontal disease is lacking, the objective of this study was to determine the ability of diseased and non-diseased gingival tissue to synthesize lipoxygenase products from the precursor arachidonic acid. Twenty-six samples of diseased tissue and nine samples of non-diseased tissue were included in our data analysis. After incubation of the tissue with 100,000 cpm [3H]-arachidonic acid, lipoxygenase products were separated by high performance liquid chromatography (HPLC) and identified by comparison with cochromatographed standards. Our results showed that inflamed gingival tissue synthesized significantly larger amounts, of LTB4(p < 0.01), LTC4(p < 0.01), LTD4(p < 0.01), LTE4(p < 0.01), 5-HETE(p < 0.05), 12-HETE(p < 0.01), and 15-HETE(p < 0.01), compared to non-diseased tissue. The lipoxygenases are more active in inflamed gingival tissue than in non-diseased gingival tissue. 12-HETE and 15-HETE were the the major metabolites formed by lipoxygenases in diseased and non-diseased human gingiva. Since we did not functionally determine the fractions separated by HPLC, our present data may only provided indirect evidence for the existence of lipoxygenase products in periodontal tissue. However, our study did establish a research model for the investigation of arachidonic acid metabolism in the pathogenesis of periodontal disease.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMed1996

[Effect of intrahippocampal microinjection of enkephalin on cellular immune function and brain IL-1 alpha gene expression in rat].

The effect of intrahippocampal microinjection of enkephalin on cellular immune function and hippocampal IL-1 alpha gene expression was studied in rats. The results showed that: (1) The proliferation activity of splenic lymphocytes stimulated by Con A was significantly increased with microinjection of Leu-enkephalin 1 microliter (18 mmol/L) or Met-enkephalin 1 microliter (18 mmol/L) into bilateral hippocampus, but was inhibited by Lipopolysaccharide 1 microliter (50 ng/microliter). The proliferative response of splenic lymphocytes to Leu-enkephalin still persisted after bilateral adrenalectomy. Low doses of Leu- or Met-enkephalin (10(-10), 10(-11) mol/L) were also capable of causing proliferative activity of the Con A- stimulated cultured splenic lymphocytes in vitro. (2) Using RT-PCR technique, IL-1 alpha gene expression was detected in hippocampus 90 min after bilateral intrahippocampal injection of LPS. The LPS-induced IL-1 alpha gene expression in hippocampus could no longer be detected 30 min after microinjection of Met- or Leu-enkephalin into hippocampus. The above results suggested that intrahippocampal enkephalin might play an important role in neuro-immunomodulation by enhancing the inhibition of IL-1 alpha gene expression in hippocampal formation.

Adrenalectomy↗