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Biomedical subjects

X Fu

Publications and source records attributed to X Fu.

At least 55 records · Page 3Linked to original sources
PubMed1998

Ischemia and reperfusion impair the gene expression of endogenous basic fibroblast growth factor (bFGF) in rat skeletal muscles.

Our previous studies showed that the amount of endogenous basic fibroblast growth factor (bFGF) was reduced after ischemia and reperfusion insult. One of the mechanisms involved in the decrease of endogenous bFGF is the increased destruction of this growth factor associated with oxygen free radical activation and inflammation. We hypothesized that the wounding also impairs the secretion of bFGF and examined the bFGF gene expression in skeletal muscles after ischemia and reperfusion insult. In this study, a rat leg ischemia (4 h) and reperfusion (24 h) injury model was prepared and the in situ hybridization method and reverse transcriptase polymerase chain reaction technique (RT-PCR) were used to evaluate the bFGF gene expression and its localization in control (normal) and injured rat skeletal muscles. The results showed that the bFGF mRNA expression was localized in the cytoplasm in control skeletal muscle, especially at the periphery inside the cells. According to the intensity of the stain, four main classes of fibers could be identified: strongly, moderately, weakly, and negatively stained fibers. Based on the positive stain, about 82% of the total fibers examined were positive for bFGF mRNA stain. In ischemic or ischemic and reperfused rat skeletal muscles, the localization of bFGF mRNA expression was similar to that in normal skeletal muscles, but only 52% in ischemic muscles and 22% in ischemic and reperfused muscles had positive bFGF mRNA staining. RT-PCR confirmed a significant decrease in bFGF mRNA expression in ischemic and reperfused rat skeletal muscles. These results suggest that the acute ischemia and reperfusion not only induce the destruction of endogenous bFGF molecule, which is stored at the extracellular matrix of the fibers, but also downregulate the bFGF gene expression. The simultaneous dysregulation of endogenous bFGF gene expression and decreased synthesis of bFGF protein suggest a possible role of this growth factor in delayed wound healing.

Animals↗
PubMed1998

New imidazole alkaloids and zinc complexes from the micronesian sponge Leucetta cf. chagosensis.

Four new imidazole alkaloids, 2-5, along with the known isonaamidine B (1) were isolated from a Pacific sponge, Leucetta cf. chagosensis, collected from Yap, Federated States of Micronesia. Among these, 4 and 5 are zinc complexes derived from isonaamidine B and isonaamidine D. The structures of the new compounds were elucidated from spectral data. Isonaamidine D (3) showed weakly antifungal activity against Aspergillus niger with MIC = 100 micrograms/mL.

Alkaloids↗
PubMed1998

Agelasines H and I, 9-methyladenine-containing diterpenoids from an Agelas sponge.

Two new diterpenes possessing a 9-methyladeninium substituent, agelasines H (5) and I (6), along with five related known ones, 1-4 and 7, were isolated from a sponge, Agelas sp. The structures of the new compounds were determined from spectral data. Compounds 2-4, 6, and 7 exhibited varying degrees of antimicrobial activity.

Adenine↗
PubMed1998

New diketopiperazines from the sponge Dysidea chlorea.

Twelve new polychlorinated diketopiperazines (7-18), along with six known ones (1-6) and a known sterol (19), were isolated from the sponge Dysidea chlorea, collected from Yap, Federated States of Micronesia. The structures of dysamides I-T (7-18) were elucidated by spectroscopic methods, and one (8) was confirmed by chemical conversion. The stereochemistry of the dysamides is discussed.

Animals↗
PubMed1998

New cyclic peptides from the ascidian Lissoclinum patella.

Four new cyclic peptides, patellamide G (2) and ulithiacyclamides E-G (3-5), along with the known patellamides A-C (6-8) and ulithiacyclamide B (9), were isolated from the ascidian Lissoclinum patella collected in Pohnpei, Federated States of Micronesia. The planar structures of these peptides were determined from 1D and 2D 1H and 13C NMR spectra. The absolute stereochemistries of the amino acid units, except for cysteine, were assigned by chiral GC analysis of N(O)-trifluoroacetyl isopropyl ester derivatives of amino acids obtained by acid hydrolysis of the intact and ozonized peptides. The structures of ulithiacyclamides E-G (3-5) were confirmed by chemical conversion. Patellamides B (7) and C (8) exhibited in vitro modulation of multidrug resistance in CEM/VBL100 cells.

Animals↗
PubMed1998

Expression and immunolocalisation of the snowdrop lectin, GNA in transgenic rice plants.

Transgenic rice (Oryza sativa L.) plants generated through particle bombardment expressed high levels of an insecticidal protein (the snowdrop lectin, GNA) directed against sap-sucking insects. Engineered plants expressed GNA either constitutively or in a tissue specific manner, depending on the nature of the promoter used to drive expression of the gene. We used specific antibodies raised against GNA to localize its expression in phloem tissue in plants engineered with the rice sucrose synthase promoter driving GNA expression. We report here molecular, biochemical and immunological analyses for fifteen independently-derived transformants out of more than 200 plants we generated.

Gene Expression↗
PubMed1998

Intravenous nitroglycerin for rapid uterine relaxation.

BACKGROUND: To investigate the effect of nitroglycerin in vitro and in vivo on human uterine contractile activity. METHODS: In vitro myometrial strips were obtained from six pregnant women at term who underwent elective cesarean section. The biopsies were mounted in tissue baths. After spontaneous or oxytocin-induced activity had been accomplished, nitroglycerin in various concentrations was added to the baths and the effects were continuously registered. In vivo, in an open study nitroglycerin was administered as a bolus injection of 100-200 micrograms intravenously to 32 women at cesarean section when uterine relaxation was urgently needed; to 22 other women after vaginal delivery for facilitation of manual removal of retained placentas, and to one patient at vaginal delivery of premature twins. RESULTS: In vitro nitroglycerin induced a dose-dependent inhibition of spontaneous as well as oxytocin-induced myometrial contractile activity. Complete muscular relaxation was obtained at a concentration of 25-50 micrograms/ml. In vivo all patients had rapid effective uterine relaxation after intravenous injection of 100-200 micrograms nitroglycerin. CONCLUSION: Nitroglycerin administered intravenously seems to be a rapid and effective uterine muscle relaxant agent without overt adverse effects on mother or fetus.

Cesarean Section↗
PubMed1998

Expression of snowdrop lectin (GNA) in transgenic rice plants confers resistance to rice brown planthopper.

Snowdrop lectin (Galanthus nivalis agglutinin; GNA) has been shown previously to be toxic towards rice brown planthopper (Nilaparvata lugens; BPH) when administered in artificial diet. BPH feeds by phloem abstraction, and causes 'hopper burn', as well as being an important virus vector. To evaluate the potential of the gna gene to confer resistance towards BPH, transgenic rice (Oryza sativa L.) plants were produced, containing the gna gene in constructs where its expression was driven by a phloem-specific promoter (from the rice sucrose synthase RSs1 gene) and by a constitutive promoter (from the maize ubiquitin ubi1 gene). PCR and Southern analyses on DNA from these plants confirmed their transgenic status, and that the transgenes were transmitted to progeny after self-fertilization. Western blot analyses revealed expression of GNA at levels of up to 2.0% of total protein in some of the transgenic plants. GNA expression driven by the RSs1 promoter was tissue-specific, as shown by immunohistochemical localization of the protein in the non-lignified vascular tissue of transgenic plants. Insect bioassays and feeding studies showed that GNA expressed in the transgenic rice plants decreased survival and overall fecundity (production of offspring) of the insects, retarded insect development, and had a deterrent effect on BPH feeding. gna is the first transgene to exhibit insecticidal activity towards sap-sucking insects in an important cereal crop plant.

Animals↗
PubMed1998

Heterogeneity of myocardial edema in isolated pig hearts after perfusion with different types of cardioprotective solutions.

The extent and distribution of myocardial edema induced by perfusion with cardioprotective solutions is of great interest. Domestic pig hearts (n = 12) were perfused in situ after aortic cross clamping either with Bretschneider's cardioplegic solution (HTK, 4 degrees C, n = 3), with a heparinized Krebs-Henseleit solution containing 30 mmol/L 2,3 Butanedionemonoxime (BDM, 4 degrees C, n = 3) or with heparinized pig blood (HPB, 24 degrees C, n = 3). After a three-hours storage period, magnetic resonance tomography (MRI) was carried out. The acquired T1-weighted data were used for the subsequent three-dimensional reconstruction based on the "Heidelberg ray-tracing technique". The small myocardial tissue blocks (n = 216) were excised from these hearts for dry weight measurements for 9 preselected regions in duplicate including ventricular papillary muscle, ventricular free wall, ventricular septum, apex, and atrial tissue. In control hearts (n = 3), dry weight was measured immediately after explantation (no MRI). The results of dry-weight measurements and three dimensional visualization were compared. Dry-weight measurements revealed that considerable myocardial edema is induced by any of the experimental procedures. The effects were most pronounced after BDM perfusion. Regardless how the edema was induced, there were significant differences of the water content within the heart: the water content in the heads of the papillary muscles and in the interventricular septum was always smaller than that of the free left- and right-ventricular walls. The heterogeneity of myocardial edema and its spatial distribution pattern could be qualitatively visualized. The experimental data (biophysical data and 3D visualization) clearly show a heterogeneity of myocardial edema induced by different types of cardioprotective solutions. As the presence of myocardial edema represents one of the crucial events in the pathophysiology of myocardial dysfunction occurring during myocardial infarction, ischemia, heart transplantation, and extracorporeal circulation, the present study represents an interesting contribution towards intravital detection and distribution of myocardial edema.

Animals↗
PubMed1998

Progesterone increases cAMP release and accumulation in isolated term human myometrium.

OBJECTIVE: To study the relationship between the action of progesterone on term human myometrial contractile activity and cAMP alterations. STUDY DESIGN: Myometrial tissues were obtained from 13 term pregnant women who underwent elective cesarean section. The contractile activity of muscle strips was recorded isometrically, and the level of cAMP in both superfusion media and experimental biopsies was measured by radioimmunoassay. RESULTS: An increased cAMP release into the superfusion media and an increased accumulation of cAMP in myometrium were observed after the addition of progesterone (3, 15 and 150 microM). Simultaneously, the frequency and tonus of contractions were increased, while the amplitude and activity area of contractions were decreased. CONCLUSIONS: The data indicate that an increase in cAMP concentration plays a role in the action of progesterone on the regulation of term human myometrial contractile activity.

Adult↗
PubMed1998

The effects of fibroblast growth factors on ischemic kidney, liver and gut injuries.

OBJECTIVE: To explore the possibility of reducing reperfusion injuries of internal organ with acidic and basic fibroblast growth factors (aFGF and bFGF). METHODS: Two kinds of ischemia and reperfusion animal models were used in this study. In rat model of superior mesenteric artery (SMA) occlusion, microvascular clamp was placed on the root of SMA to cut off the blood flow for 45 minutes, and then the clamp was removed. In rat model of bilateral renal ischemia and reperfusion, both renal arteries were clipped to get complete cessation of blood flow for 60 minutes, then the blood flow was allowed to return. At the onset of reperfusion, the doses of 4.0 micrograms/rat of bFGF in SMA occluded rats or 2.6 micrograms/rat of aFGF in rats with acute renal injury were administered through the jugular vein. The liver and renal function examination, tissue bacterial study and histopathological evaluation were done to evaluate the treatment results. RESULTS: The functional impairment of ischemic liver, gut and kidney were reduced with venous administration of aFGF or bFGF at the onset of reperfusion. The results of pathological and tissue bacterial examination supported the assertion of significant protective effects of FGFs. CONCLUSIONS: The protective effects of FGFs may come from the non-mitogenic effects of FGFs at the early and the mitogenic effects at the late stage of tissue repair. These results indicate a potential for clinical use of FGFs as a therapeutic modality in ischemic visceral organ injuries in the future.

Animals↗
PubMed1998

[Basic fibroblast growth factor (bFGF) and wound healing: a multi-centers and controlled clinical trial in 1024 cases].

UNLABELLED: To evaluate the effects of bFGF on wound healing and the side-effects of bFGF, a multi-centers and controlled clinical trial were carried out in 32 hospitals in China. One thousand and twenty-four cases with acute wounds such as burn, donor site or operative wound and chronic wounds such as bed sore, draining sinus, ulcer were treated with bFGF. Another 826 cases with the similar wounds were used as control. The results showed: 1. The duration of wound healing was shorted 3-4 days in trial group when compared with the contorl; 2. The successful rates from bFGF on promoting the wound healing for burns, operative wounds and chronic dermal ulcers was 95.2%, 96.5% and 93.5%, respectively; 3. No adverse reaction was found. CONCLUSION: 1. bEGF can make the "silent" reparative cells dividing and proliferating. 2. bFGF can improve the quality and the velocity of wound healing.

Administration, Topical↗
PubMed1998

[Fibronectin mRNA expression in hypertrophic scars].

OBJECTIVE: This study was to compare the content of fibronectin messenger RNA in the normal skin and hypertrophic scars. METHODS: The mRNA levels of fibronectin were measured by quantitative RT-PCR. RESULT: The study revealed that in vivo, the content of fibronectin messenger RNA was higher in hypertrophic scars than in normal skin. CONCLUSION: It indicates that altered regulation of extracellular matrix components is an important factor for abnormal human wound healing.

Adolescent↗
PubMed1998

[Detection of 17-ketosteroid and 17-hydroxycorticosteroid in urine after separation and collection by foam rubber].

Using foam rubber 17-ketosteroid (17-KS) and 17-hydroxycorticosteroid (17-OHCS) were separated and collected in urine. 17-KS and 17-OHCS were eluted down from the foam rubber with alcohol, colour reaction can be respectively produced by m-dinitrobenzene and phenyhydrazine hydrocholoride, then both of them were detected by spectro-photometry. The standard deviation of this method was +/- 0.032, and its minimum detectable concentration was 0.01 microgram.ml-1. The recovery rate of 17-KS and 17-OHCS estimation was from 99.0% to 101.0%, with co-efficients of variation less than 6.23%.

17-Hydroxycorticosteroids↗
PubMed1998

[Ischemia and reperfusion reduce the mRNA expression of endogenous basic fibroblast growth factor (bFGF) in rat skeletal muscles].

OBJECTIVE: To explore the expression of bFGF gene in normal and wounded rat skeletal muscles. METHODS: In situ hybridization and quantitative PCR methods were used to evaluate the location of basic fibroblast growth factor (bFGF) mRNA and the amount of bFGF mRNA expression in normal, ischemic or ischemic and reperfused rat skeletal muscles. RESULTS: According to the intensity of the stain in situ hybridization, four main classes of fibers could be identified: strong, moderate, weak and negative stained fibers. bFGF mRNA was found in the cytoplasm in both normal and wounded muscles; however, the signal intensity was much stronger in normal muscles. In the normal muscles, bFGF mRNA was distributed irregularly and sparsely, and 82% of fibers had positive bFGF mRNA staining, and only 52% and 22% of fibers in ischemic or ischemic and reperfused muscles were positive for bFGF mRNA staining in situ hybridization. The results in quantitative PCR study supported the concept of the reduced bFGF mRNA expression in the wounded muscles. CONCLUSIONS: The loss of stored bFGF in wounded skeletal muscles as we showed previously is also caused by its increased damage and reduced secretion.

Animals↗
PubMed1998

[Clinical study on tripterygium wilfordii complex ester tablet in treating rheumatoid arthritis].

OBJECTIVE: To observe the curative effect, toxic and side effect of Tripterygium Wilfordii Complex Ester Tablet (TWT, a preparation of Folium Tripterygium wilfordii) in treating rheumatoid arthritis. METHODS: Two hundred and seventy seven patients were observed with prospective, multicentric and random double-blind control method. One hundred and forty cases of TWT group were treated with TWT 2 tablets each time, 3 times a day orally, and the other 137 cases treated with Tripterygium Wilfordii Polycoside Tablet (TPT, a preparation of Radix Tripterygium Wilfordii) 2 tablets each time were taken as control, 3 times a day orally. The therapeutic course for both groups was 6 weeks. RESULTS: The markedly controlled rate of the TWT group was 26.71% and the total effective rate was 86.43%, while those in the control group were 26.28% and 83.94% respectively, the difference between the two groups was insignificant (P > 0.05). The occurrence of side-effect in the two groups was 20.00% and 23.35% respectively, also showed no significant difference (P > 0.05). CONCLUSION: The Folium Tripterygium Wilfordii preparation is similar in efficacy and security to the Radix Tripterygium Wilfordii preparation.

Adolescent↗
PubMed1997

Titration kinetics of Asp-85 in bacteriorhodopsin: exclusion of the retinal pocket as the color-controlling cation binding site.

The spectrum (the purple blue transition) and function of the light-driven proton pump bacteriorhodopsin are determined by the state of protonation of the Asp-85 residue located in the vicinity of the retinal chromophore. The titration of Asp-85 is controlled by the binding/unbinding of one or two divalent metal cations (Ca2+ or Mg2+). The location of such metal binding site(s) is approached by studying the kinetics of the cation-induced titration of Asp-85 using metal ions and large molecular cations, such as quaternary ammonium ions, R4N+ (R = Et, Pr, a divalent 'bolaform ion' [Et3N+-(CH2)4-N+Et3] and the 1:3 molecular complex formed between Fe2+ and 1,10-phenanthroline (OP). The basic multi-component kinetic features of the titration, extending from 10(-2) to 10(4) s, are unaffected by the charge and size of the cation. This indicates that cation binding to bR triggers the blue --> purple titration in a fast step, which is not rate-determining. In view of the size of the cations involved, these observations indicate that the cation binding site is in an exposed location on, or close to, the membrane surface. This excludes previous models, which placed the color-controlling Ca2+ ion in the retinal binding pocket.

Aspartic Acid↗