Search PubMed⌕ Search

Biomedical subjects

G Wu

Publications and source records attributed to G Wu.

At least 595 records · Page 33Linked to original sources
PubMed1991

[Application of a monoclonal antibody SZ-51 specific for activated human platelets in canine thrombosis imaging].

To detect specifically the localization of thrombus in vivo, we prepared a monoclonal antibody (McAb) SZ-51 specific for an alpha-granule membrane protein (GMP-140) exposed on the surface of activated human platelets. 131I labeled SZ-51 antibody combined preferentially with thrombus induced by thrombin in vitro. Owing to McAb SZ-51 crossreaction with the activated platelets of dogs, thrombi in both femoral artery and vein were prepared and imaged with SPECT in dogs. The ratio of radioactivity between thrombi and blood pool was significantly increased in both arterial and venous thrombus after injection of 131I-SZ-51, especially at the 4th hour. Moreover, the imaging of arterial thrombus is better than that of venous thrombus. However, both arterial and venous thrombi could not be imaged by the injection of 131I-nonimmune IgG. These findings were in agreement with the radioactivity ratios between the removed thrombi and blood 24 hours after injection. Therefore, these results indicate that McAb SZ-51 has the power of detecting thrombi in vivo.

Animals↗
PubMed1991

Characterization and comparison of antimicrobial susceptibilities and outer membrane protein and plasmid DNA profiles of Pasteurella haemolytica and certain other members of the genus Pasteurella.

The outer membrane protein (OMP), plasmid, and antimicrobial resistance profiles of Pasteurella haemolytica serotypes 1 through 12, a bovine isolate of P multocida, a chicken isolate of P multocida, and an unidentified Pasteurella species of bovine origin were examined. Isolates of P haemolytica serotypes belonging to the same biotype possessed similar OMP profiles. Biotype A isolates contained 2 prominent OMP of 43 kilodaltons (kD) and 29 kD, whereas biotype-T serotypes contained 3 major OMP of 43, 36, and 25 kD. The major OMP profiles of the 2 P multocida isolates and the unidentified Pasteurella species were different from each other and from P haemolytica isolates. Plasmid DNA screening indicated both plasmid-containing and plasmid-free P haemolytica and P multocida isolates. Multiple drug resistance was found in pasteurellae isolates with and without plasmids. However, a relationship between drug resistance and plasmid isolation was found in 3 of 4 haemolytica serotype 1 field isolates, all of which contained a 2.51-megadalton plasmid and had multiple drug resistance for benzylpenicillin, ampicillin, streptomycin, and tetracycline.

Ampicillin Resistance↗
PubMed1991

An antihypertensive factor in the erythrocytes of essential hypertensive subjects--effects on blood pressure and calcium uptake by vascular tissue in rats.

An extract prepared from the erythrocytes of essential hypertensive subjects was found to significantly lower systolic blood pressure (SBP) in spontaneously (SHR) and renal hypertensive rats (RHR) following a single intravenous or intraperitoneal injection: The maximum SBP reduction was 42.8 mmHg in SHR and 38.3 mmHg in RHR. In contrast, this hypertensive factor (AHF) had little effect on normotensive Wistar Kyoto and Wistar rats. AHF was also found to significantly suppress Ca2+ uptake by vascular smooth muscle in the mesenteric artery and aorta of hypertensive and normotensive rats (P less than 0.05, respectively). Furthermore, AHF prepared from the erythrocytes of normotensive subjects was shown to have a similar effect.

Animals↗
PubMed1991

[Experimental study of laser ablation on lethal arrhythmias in dogs].

To study the effect of laser ablation on arrhythmogenic ventricular myocardium, we applied aconitine on 36 local epicardial sites of ventricles (22 in LV, 14 in RV) in 12 dogs. Severe monographic persistent VTs or VFs were induced by aconitine and then these foci were irradiated by Nd: YAG laser. RV refractoriness (RVR) and local epicardial pacing threshold (LEPT) were measured by programmed electrical stimulation (PES) before aconitine applying and after resuming sinus rhythm. That VT or VF could not be induced by PES and the heart had persistent sinus rhythm was considered success. Aconitine doses were 7.9 +/- 4.8 micrograms in LV, 3.3 +/- 1.9 micrograms in RV, P less than 0.01. The data of time from aconitine applying to the appearance of VT were 237 +/- 228 s in LV and 148 +/- 101 s in RV, P less than 0.05. VF incidence rate was 75% (27/36). All of VT, VF could be abolished by mapping-guided laser irradiation on VT foci. The mean laser energy was 1542 +/- 893 joules (n = 36). RVR and LEPT increased significantly (P less than 0.001) after tests. Results showed that: (1) Lethal ventricular arrhythmias could be induced by giving little aconitine on the ventricular epicardium; (2) Mapping-guided lasering on arrhythmogenic myocardium could eradicate VT and VF; (3) RVR and LEPT would increase greatly after ablation.

Aconitine↗
PubMed1991

[Effect of electrical stimulation and lesion of N reticularis paragigantocellularis lateralis on acupuncture analgesia in rats].

The present study was aimed to investigate the role of the reticularis paragigantocellularis lateralis (RPGL) in acupuncture analgesia. Tail-flick response to electrical stimulation of the tail skin was taken as index of pain response. The first part of the study consisted of four groups: (1) surgical control, (2) electro-acupuncture, (3) electrical stimulation of RPGL, and (4) stimulation of RPGL simultaneously with electro-acupuncture. The pain threshold in the first group was quite stable during the experiments, but increased significantly after electro-acupuncture and/or brain stimulation (n = 14, P less than 0.01; n = 8, P less than 0.001; n = 14, P less than 0.001). The pain threshold of the fourth group increased much more than the second and the third group (P less than 0.001, P less than 0.01). In the second part of the study, the effect of electro-acupuncture was reduced significantly after electrical lesion of the RPGL unilaterally (n = 12, P less than 0.01). The present work indicates that electrical stimulation of RPGL enhances electro-acupuncture analgesia, whereas the lesion of RPGL reduces it. It is suggested that RPGL plays a role in acupuncture analgesia.

Acupuncture Analgesia↗
PubMed1990

Lactate production is the major metabolic fate of glucose in splenocytes and is altered in spontaneously diabetic BB rats.

Enhanced glucose metabolism is necessary to support the activation and proliferation of lymphocytes. To define further quantitatively the metabolic fates of glucose and assess glucose utilization both in normal cells and in an autoimmune disease with abnormal lymphocytes, [U-14C]glucose conversion into 14CO2 and the production of lactate and pyruvate were measured in splenocytes. Cells from non-diabetes-prone (BBn) and spontaneously diabetic (BBd) rats were studied both freshly isolated 'resting' and cultured for 96 h with and without concanavalin A (Con A) stimulation. (1) Lactate was confirmed to be the major end product in both freshly isolated (53% of utilized glucose) and unstimulated cultured (62% of utilized glucose) cells from BBn animals studied at (2-8) x 10(6) cells/ml concentration. The use of concentrations from 10 x 10(6) to 300 x 10(6) cells/ml resulted in progressively less lactate production per 10(6) splenocytes. (2) Cells from BBd animals after stimulation with Con A incorporated less [3H]thymidine and produced significantly less lactate (155 +/- 14 versus 305 +/- 24 nmol/2 h per 10(6) cells) than did BBn cells (P less than 0.05). (3) However, more lactate (101 +/- 8 versus 78 +/- 6 nmol/5 h per 10(6) cells) was produced by 'resting' cells from BBd animals compared with BBn (P less than 0.03), and this difference was sustained after 4 days in culture. (4) Significantly greater amounts of pyruvate were produced by BBd than by BBn cells, particularly when stimulated with Con A, suggesting an alteration in the availability of reducing equivalents in BBd cells. (5) These results are consistent with prior metabolic as well as immunological 'activation' of cells in vivo in the BB diabetic animals.

Adenosine Triphosphate↗
PubMed1990

The macular photostress test in diabetic retinopathy and age-related macular degeneration.

We propose the macular photostress test for the evaluation of macular function in the office setting. Eighty eyes were tested and divided into four diagnostic categories: background diabetic retinopathy, diabetic macular edema, age-related macular degeneration, and normal. The recovery times for the eyes with age-related macular degeneration were longer than for eyes with macular edema (P = .03). Age-matched patients with age-related macular degeneration had longer recovery times than did those without age-related macular degeneration (P = .0001). A possible explanation is that the prolonged recovery time in the eyes with age-related macular degeneration reflects that the anatomic lesion is located in the retinal pigment epithelium-photoreceptor complex. In comparison, the eyes with macular edema, whose lesion is in the inner retina and not the retinal pigment epithelium, show a less-prolonged recovery time than the eyes with age-related macular degeneration.

Adolescent↗
PubMed1990

The effect of ketone bodies on protein turnover in isolated skeletal muscle from the fed and fasted chick.

1. The addition of 4 mM acetoacetate or DL-beta-hydroxybutyrate to the incubation medium decreased the rate of protein synthesis without influencing the rate of protein degradation in extensor digitorum communis (EDC) muscles from fed chicks and decreased the rates of protein synthesis and degradation in muscles from fasted chicks. 2. Ketone bodies markedly decreased intracellular concentrations of glutamine in EDC muscles from fed chicks by increasing glutamine oxidation. 3. The addition of 0.5 mM glutamine to incubation media containing 1.0 mM glutamine reversed the ketone body-induced decrease in intracellular glutamine concentration to the control value and blocked the inhibiting effect of ketone bodies on protein synthesis in skeletal muscles from fed chicks. 4. The addition of 5 mM pyruvate blocked the ability of ketone bodies to increase glutamine oxidation and prevented the associated decrease in intracellular glutamine concentration and the rate of protein synthesis in EDC muscles from fed chicks. 5. These results suggest that ketone bodies can act directly on skeletal muscle to inhibit the rate of protein synthesis in muscles from fed chicks by decreasing intracellular glutamine concentration by increasing its oxidation.

Amino Acids↗
PubMed1990

Variations in c-fos mRNA expression during serum induction and the synchronous cell cycle.

Induction of c-fos mRNA levels associated with the stimulation of growth by fetal bovine serum following quiescence was examined in three cell types following brief (24 h) serum starvation. Starved NIH-3T3 and HeLa S3 cells experienced c-fos mRNA induction 20-30 min after addition of serum. In contrast, Swiss-3T3 cells expressed c-fos constitutively following serum starvation. The pattern of oncogene expression coincided with the level of quiescence of each cell line prior to induction. Serum inductions of c-fos expression was dependent upon the response of each cell line to serum starvation, c-fos expression was also examined in HeLa S3 cells that had been separated into sequential cell cycle phases by centrifugal elutriation, c-fos expression peaked during the earliest part of the synchronous G1 phase. The amount of c-fos mRNA measured was approximately twice that found during other cell cycle phases. This suggests that, in addition to its role during the transition from quiescence, the c-fos gene product may play a regulatory role during the earliest part of G1 phase of the continuous cell cycle.

Animals↗
PubMed1990

Preparation of a monoclonal antibody, SZ-51, that recognizes an alpha-granule membrane protein (GMP-140) on the surface of activated human platelets.

To identify the changes on the platelet plasma membrane after platelet activation, we prepared monoclonal antibodies specific for activated platelets. Hybridoma cell line SZ-51 was screened for antibodies which bound to thrombin activated platelets but not to resting platelets. 125I-SZ-51, and IgG1, bound 780 molecules/platelet on resting platelets. However, it bound 11,000 molecules/platelet on thrombin activated platelets with high affinity (4.2 nmol/L). The isolated protein using affinity chromatography showed a single band in both periodic acid-Schiff and Coomassie blue staining. Immunoblot analysis revealed that SZ-51 reacted with a 140,000 molecular weight protein which was identified to be alpha-granule membrane protein (GMP-140) in radioimmunoassay. These results demonstrate that the antigen recognized by SZ-51 is GMP-140, which is expressed on the plasma membrane of activated platelets.

Antibodies, Monoclonal↗
PubMed1990

Plasmid content of piliated and nonpiliated forms of Moraxella bovis.

Plasmid profiles were compared between nonpiliated and piliated forms of Moraxella bovis isolates. The piliated form of M bovis isolate IBH64 contained 1 fewer plasmid than did the nonpiliated form. Piliated and nonpiliated cells of IBH64 contained plasmids having molecular size of 45, 32.8, 4.9, and 4.6 kilobases (kb). Single- and double-restriction endonuclease digestion by Ava I and Nde I indicated that the size of the additional plasmid carried by the nonpiliated form of IBH64 was approximately 43.6 kb. The M bovis isolates, Newport and GRS, contained the same number of plasmids in either their piliated or nonpiliated form.

DNA Restriction Enzymes↗
PubMed1990

Effects of four dopamine agonists on l-tetrahydropalmatine-induced analgesia and electroacupuncture analgesia in rabbits.

The effects of icv 4 dopamine (DA) agonists on analgesia caused by iv l-tetrahydropalmatine (THP) 8 mg/kg or by electro-acupuncture (EA) were studied by using the potassium iontophoretic dolorimetry in rabbits. The results showed that both THP-induced analgesia and EA analgesia were markedly attenuated by icv of DA or apomorphine (Apo), 2 mixed D1/D2 agonists. Similar results were obtained when SKF-38393, a selective D1 agonist, was applied. On the contrary, quinpirole hydrochloride (Qui), a selective D2 agonist, was found to enhance the analgesic action of THP or EA. However, DA, Apo, SKF-38393 or Qui per se did not influence the baseline pain threshold. All these observations indicate that functional alterations in DA receptor activities may be involved in THP-induced analgesia and EA analgesia, in which D1 and D2 subtype receptors exert different roles.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1990

[A study on the dental adhesive containing phosphate diesters].

Although a lot of kinds of dental adhesives have been applied recently, all of them cannot meet clinical requirement completely. This paper reports a new dental adhesive containing partial phosphate diesters developed by us. We synthesized aryl phosphorodichloridates (APDC), nine kinds of phosphate diester (PDE) adhesive monomers, sodium p-toluenesulfinate (TSS) and p-toluenesulfinic acid (TSA) accelerators, polymethyl methacrylate (PMMA) powder and the other compounds. The chemical structures of PDE adhesive monomers were confirmed by IR, 1HNMR, 31PNMR, refractive index and elementary analysis etc. The results showed that the tensile bond strength (TBS) between PDE dental adhesive and human tooth was better than others reported in China and some others reported in literature.

Dental Cements↗
PubMed1990

The differences of serum cholesterol and lipoproteins in animals susceptible and nonsusceptible to atherosclerosis.

The differences of serum lipid and lipoprotein (LP, profiles of animals susceptible (rabbit) and nonsusceptible (Beijing duck) to atherosclerosis as well as the distribution of apolipoprotein (apo) A-I and its catabolism in vivo were studied. Eight items, i.e. total cholesterol (TC), high density lipoprotein (HDL) cholesterol, triglyceride, percentage of alpha-LP and beta-LP, beta-LP concentration, lecithin cholesterol acyl transferase (LCAT), and agarose and polyacrylamide gel electrophoresis of both species were assayed before and after feeding a high fat, high cholesterol diet. Results indicate that the exogenous cholesterol consumed by Beijing ducks was carried and transported by HDL, while that in rabbits was transported by low density lipoprotein (LDL). The biological half lives of apo A-I in serum and in HDL were 41.1 +/- 2.4 and 42.8 +/- 1.7 h respectively, and its distribution in different organs was in the order of liver greater than kidney greater than spleen greater than lung greater than heart greater than intestine greater than muscles greater than aorta. These results show that the liver is the major organ for metabolizing HDL apo A-I, and the kidney is also important. The results also imply that in Beijing ducks the cholesterol carried by HDL may be catabolized through apo A-I receptors in the liver and kidney. The differences in cholesterol binding and in lipoprotein and apolipoprotein metabolism of the two species provide important clues for the elucidation of the pathogenesis of atherosclerosis.

Animals↗