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Biomedical subjects

W Y Liu

Publications and source records attributed to W Y Liu.

At least 73 records · Page 4Linked to original sources
PubMed1994

[The shunt for portal hypertension in children].

Ten children with portal hypertension were treated with shunt operations. Among them, 9 were extrahepatic and one was intrahepatic lesion. The follow-up for 1-14 years showed: (1) In the 3 patients treated with splenopneumopexy, hemorrhage from the esophageal varices were controlled and portopulmonary shunt was demonstrated by Doppler ultrasound and radionuclide; (2) In the 6 patients treated with mesocaval shunt, 3 were non-recurrent bleeding and 2 died of recurrent bleeding or other disease respectively; (3) In one child with hepatic cirrhosis (11 year old) treated by splenorenal shunt, non-recurrent bleeding occurred. The authors suggest the portopulmonary shunt by splenopneumopexy is safe and effective for the portal hypertension of children.

Child↗
PubMed1994

Effects of cyproheptadine on TXB2 and 6-keto-PGF1 alpha plasma levels in rabbits with hemorrhagic shock.

Profound hemorrhagic shock was produced in 26 rabbits by exsanguination via carotid artery until blood pressure (BP) = 5.3 kPa (40 mmHg) for a period of 90 min. Rabbits were equally divided into a cyproheptadine (Cyp) treated group and a control group. The blood samples before and 90 min after shock and 30 min after liquid and blood infusion and administering Cyp (10 mg.kg-1) were collected from the carotid artery. With radioimmunoassay, we measured the thromboxane B2(TXB2) and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) contents in plasma. The results indicated that the TXB2 and 6-keto-PGF1 alpha levels during shock (1024 +/- 924, 30 +/- 32) and after liquid and blood infusion (990 +/- 943, 60 +/- 54) were higher than those (221 +/- 134, 6 +/- 4) in normal rabbits (P < 0.01, P < 0.05). Cyp reduced obviously the TXA2 plasma level in rabbit with shock (304 +/- 299 vs 990 +/- 943, P < 0.05). We conclude that the decrease of TXB2 content is one of the possible mechanisms of cyproheptadine anti-shock effect.

6-Ketoprostaglandin F1 alpha↗
PubMed1994

[Study of clinical pathology and discussion of surgical strategy in comprehensive mitral valvuloplasty].

The results of clinical pathologic study of 162 mitral valves (MV) intraoperatively and pathologic anatomy of 8 excised MV were reported. Type I 64 cases, type II 23 cases and type III 75 cases. The pathogenic causes were congenital heart disease in 22 cases degeneration in 27 cases infective endocarditis in 1 case and rheumatic disease in 112 cases. Of the excised MV, 7 rheumatic lesion with type III. All valve components were involved. The valve leaflets thickened significantly and valve orifice changed like a funnel or semi-funnel shape. Under light microscope there was no interface between the increased collagen fibers and the valve tissue. Some superficial collagen fibers appeared hyalinosis. The calcification, local necrosis and inflammatory cell infiltration could be seen in some cases but the rheumatic bodies and the chordae tendineae wrapped up in the thickened valve tissue only in one case respectively degenerative lesion with thin chordae tendineae which appeared muco-hyalinosis and ruptured in three points. According to the clinical pathology of MV the indication and surgical technique are discussed.

Adolescent↗
PubMed1993

Can daily dietary arginine supplement affect the function and subpopulation of lymphocytes in patients with advanced gastric cancer?

Since arginine can stimulate lymphocyte proliferation in the healthy human, its effect on lymphocyte proliferation in vitro was studied in 7 patients with far advanced gastric cancer. These patients with normal nourishment were ambulatory and could consume a regular diet. A daily dietary supplement of 30 g arginine for 7 days did not alter the total lymphocyte counts or the T/B cell ratio in the peripheral blood. Enhancement of lymphocyte proliferation in response to mitogen stimulation was not observed. Furthermore, an in vitro study on the effect of arginine on phytohemagglutinin-stimulated lymphocyte proliferation showed that lymphocytes from gastric cancer patients had poorer responses than those obtained from normal subjects, despite the supplement in the culture medium with normal serum, patient serum, or fetal bovine serum. Arginine ingestion did not impair liver function and had no detectable side effects except transient nausea in 1 patient. These results indicate that dietary arginine supplement appears safe but does not stimulate lymphocyte function in far advanced gastric cancer patients. The suppressed immune function in gastric cancer patients may be the result of their intrinsic lymphocyte defect.

Adenocarcinoma↗
PubMed1993

[Effect of anti-opioid peptide sera on oxytocin-induced enhancement of electroacupuncture analgesia].

The effects of intracerebroventricular injection of Anti-opioid peptide sera on oxytocin-induced enhancement of electroacupuncture (EA) analgesia were observed in this study. It was found that injection of anti-beta-endorphin serum (AEPS) alone could attenuate EA analgesia in rats. Injection of AEPS prior to intraventricular injection of oxytocin could not block the enhancement of EA analgesia by oxytocin. The antidynorphin A1-13 serum (ADYNS) alone could also reduce the EA analgesia, whereas injection of ADYNS prior to injection of oxytocin could potentiate the enhancement of EA analgesia by oxytocin. However, neither the anti-methionine enkephalin serum nor the anti-leucine enkephalin exerted any effect on the enhancement of EA analgesia by oxytocin. The above results showed that the dynorphin attenuate oxytocin-induced enhancement of EA analgesia, but Beta-endorphin and enkephalin do not affect this role of oxytocin. These data suggest the enhancement of EA analgesia by oxytocin is not dependent upon the endogenous pioid peptides in brain.

Acupuncture Analgesia↗
PubMed1992

The mechanism of action of trichosanthin on eukaryotic ribosomes--RNA N-glycosidase activity of the cytotoxin.

Trichosanthin is a ribosome-inactivating protein from root tubers of Trichosanthes kirilowii Maxim. In this paper, the mechanism of action of trichosanthin on eukaryotic ribosomes was studied. A fragment of about 450 nucleotides was released from 28S ribosomal RNA after treatment of rat liver ribosome with trichosanthin and its isolated ribosomal RNAs were treated with aniline. Analysis of nucleotide sequence of 5' terminus of this fragment revealed that the aniline-sensitive site of the phosphodiester bond was between positions A4324 and G4325 in the 28S rRNA. Adenine was recovered by ion-exchange column chromatography from the 50% ethanol soluble fraction of the reaction mixture in which rat liver ribosomes were treated with trichosanthin. Thin-layer chromatographic analysis indicated that 1 mol of adenine was released from 1 mol of ribosomes. When the ribosomes were incubated with trichosanthin in the presence of inorganic [32P]phosphate, little incorporation of radioactivity into 28S rRNA was observed, indicating that the release of adenine was not mediated by phosphorolysis. These results demonstrate that trichosanthin inactivates the ribosomes by cleaving the N-C glycosidic bond of adenylic acid at 4324 of 28S rRNA in a hydrolytic fashion.

Adenosine Monophosphate↗
PubMed1992

Role of early afterdepolarization in familial long QTU syndrome and torsade de pointes.

Torsade de pointes (TdP) syncopal episodes were almost invariably precipitated by emotional stress or menstruation in a 17-year-old girl. U wave accentuation occurred during sinus rhythm without pauses in periods of heightened sympathetic tone. To examine the role of early afterdepolarization (EAD), monophasic action potentials were recorded during ventricular extrasystoles and TdP occurring spontaneously and induced by ventricular pacing. The effects of lidocaine, verapamil, propranolol, and epinephrine were assessed. Our data show that: (1) EAD plays a significant role in the genesis of familial long QTU syndrome and TdP; (2) rapid ventricular pacing causes postpause-dependent EADs, U waves, and TdP; and (3) EAD is enhanced by epinephrine infusion in the absence of pause, whereas EAD-triggered firing is inhibited by verapamil and propranolol but not by lidocaine.

Action Potentials↗
PubMed1992

[Effect of Asu-AVT on electroacupuncture (EA) analgesia].

The Asu-AVT (1,6-aminosuberic acid -8-arginine-vasotocin) in an analogue of 8-arginine-vasotocin (AVT) which is one of pineal hormones. The effect of Asu-AVT on the pain threshold and EA analgesia was studied in rats. An increase of 16.2-41.5% in pain threshold was observed within 70 min. after ivc of Asu-AVT (75ng), while the Asu-AVT injection in combination with EA produced a significant increase of 164.6-309.1% in pain threshold, which was much higher than that in the saline-EA group (p < 0.05-0.01). The effect of Atu-AVT is analogous to that of oxytocin and arginine-vasopressin. The data indicate ivc of ASu-AVT not only elevates the pain threshold, but also enhances the EA analgesia. These results suggest that the pineal hormone, AVT may play a role in the EA analgesia.

Acupuncture Analgesia↗
PubMed1990

Cloning and nucleotide sequence analysis of the human beta-microseminoprotein gene.

Beta-microseminoprotein (MSP) is a small protein (94 amino acids) synthesized by the epithelial cells of the prostate gland and secreted into the seminal plasma. Restriction endonuclease mapping of human genomic DNA with a human MSP cDNA probe identified a 19 kilobase (Kb) hybridizing band in both EcoRI and BamHI digestions. Subsequently, the 19 Kb EcoRI fragment of human genomic DNA containing the MSP gene was isolated and cloned into an EMBL4 phage vector. Screening of the recombinant phages resulted in the isolation of one clone containing the MSP gene. Restriction endonuclease mapping and sequence analysis of this clone revealed the human MSP gene of approximately 15 Kb in length. The gene contains four exons and three large introns of approximately 6, 1, and 7 Kb.

Amino Acid Sequence↗
PubMed1990

[The role of central oxytocin in electroacupuncture analgesia].

The effects of intraventricular injection (ICV) of oxytocin (OT) and antioxytocin serum (AOTS) on the pain threshold and electroacupuncture (EA) analgesia in rats were investigated in this study. The potassium iontophoresis induced tailflick was used to measure the pain threshold. An increase of 20-38% in the pain threshold was observed within 80 min after OT injection (50 ng), while the OT administration (50 ng) in combination with EA produced a dramatic increase of 139-234% in the pain threshold, which was much higher than that in the saline-EA group (P less than 0.05 or 0.01). The OT effect was dose-related in the range between 25-100 ng. Although ICV of AOTS did not change the pain threshold, the EA analgesia became weakened significantly. After injection of AOTS, EA only produced an increase of 47-61% in the pain threshold, while following ICV injection of normal rabbit serum instead of AOTS the EA could cause a rise of 104-123% in the pain threshold. There was a significantly statistical difference between the above two groups (P less than 0.05-0.01). The data indicate that ICV of OT not only elevates the pain threshold, but also enhances the EA effect, and that AOTS attenuates the EA analgesia. These results suggest that endogenous oxytocin in the central nervous system may play a role in the electroacupuncture analgesia.

Acupuncture Analgesia↗
PubMed1989

Transcripts of the insulin-like growth factors I and II in human hepatoma.

Using complementary DNAs of human insulin-like growth factors as probes, expressions of the insulin-like growth factors I and II mRNA were examined in seven human hepatoma tissues and their adjacent nontumorous livers. The level of insulin-like growth factor I mRNA in hepatoma was lower than that in the nontumorous liver control. This phenomenon was probably caused by the low expression of human growth hormone receptor in hepatoma tissues. The levels of insulin-like growth factor II mRNA vary among hepatomas. Some show elevated expression; some have diminished expression compared to their nontumorous liver counterparts. In four of the seven hepatomas, expression of fetal forms of insulin-like growth factor II transcripts was observed and may represent dedifferentiation of insulin-like growth factor II expression during hepatocarcinogenesis.

Carcinoma, Hepatocellular↗
PubMed1989

Measurement of thermal expansion coefficient of human teeth.

The coefficient of thermal expansion of specimens from 60 freshly extracted human teeth were measured over the range 10-80 degrees C using a dilatometer. The coefficient increased rapidly above 50 degrees C, but there was no significant variation with tooth age between 10 and 70 years. The average values obtained were 16.96 (SD 3.83) x 10(-6)/degrees C for enamel, 10.59 (SD 2.38) x 10(-6)/degrees C for dentine, 11.90 (SD 4.42) x 10(-6)/degrees C for crowns and 9.44 (SD 0.61) x 10(-6)/degrees C for roots.

Adolescent↗
PubMed1989

[Effect of acupuncture of zusanli (St. 36) on the content of beta-endorphin of the gastrointestinal tract in rats].

The present study attempts to search the mechanism with which Zusanli regulates the gastrointestinal function by using radioimmunoassay to measure the contents of immunoreactive beta-endorphin (ir-beta-Ep) in gastrointestine, anterior lobe of the pituitary and plasma of the rats after electro-acupuncture of Zusanli. The findings showed that the contents of ir-beta-Ep in the gastroparietal mucous membrane, pyloric mucous membrane, duodenum, jejunum and ileum were significantly elevated 30 min after electro-acupuncture of Zusanli. But the contents of ir-beta-Ep in the anterior lobe of the pituitary and plasma were not changed. These results suggested that it may be through the endogenous opiate peptides in gastrointestine that Zusanli regulates the function of the gastrointestinal tract.

Acupuncture Points↗
PubMed1989

Prevention of myocardial reperfusion injury with free radical scavengers. An experimental study.

The changes in endogenous superoxide dismutase (ESOD) during myocardial ischemia and reperfusion and the efficacy of oxygen free radical scavengers in myocardial protection were investigated in an isolated heart model connected with the recirculating nonpulsatile perfusion circuit. Subjected to a 2-hour period of global ischemia (27 C), the heart was reperfused with 37 C oxygen diluted auto-blood for 60 minutes. Superoxide dismutase plus catalase was added into the cardioplegic solution and reperfusates. ESOD activity was measured by pyrogallol method. The results of the experiment showed that ESOD activity after ischemia and reperfusion was decreased and the addition of oxygen free radical scavengers (SOD and CAT) to the cardioplegic solution and the reperfusates greatly reduced the leakage of myocardial enzymes, coronary vascular resistance, and the ultrastructural damages of the myocardium. These results suggest that the use of SOD and CAT may inhibit myocardial reperfusion injury by scavenging oxygen-derived free radicals.

Animals↗
PubMed1989

[Determination of isosorbide dinitrate and its degradation products in pharmaceuticals by gradient RP-HPLC].

Isosorbide dinitrate (ISDN) and its degradation products isosorbide-5-mononitrate (5-ISMN) and isosorbide-2-mononitrate (2-ISMN), in a spray formulation were separated and determined by step gradient RP-HPLC within 8 minutes. A Shimadzu LC-4A liquid chromatograph, Nucleosil C18 5 microns 150 X 4.6 mm (ID) column, SPD 2AS spectrophotometric detector at 220 nm with variable attenuation were used, the sensitivity was kept at 0.16 AUFS in the first 4.5 min and changed to 2.56 AUFS during 4.5-12 min. Solution A (70% methanol) and solution B (5% methanol) were employed as mobile phase at a flow rate of 1.0 ml/min in gradient elution. Good results could be obtained by CR 3A data module using external standard method. The recoveries were 98.20% (ISDN), 96.92% (5-ISMN) and 95.83% (2-ISMN) and the coefficients of correlation were 0.9990 (ISDN), and 0.9994 (5-ISMN and 2-ISMN).

Chromatography, High Pressure Liquid↗
PubMed1989

Genomic organization of the human retinoblastoma gene.

Sequence analysis of the human retinoblastoma gene cDNA revealed the presence of repeated elements in the form of direct repeats, inverted repeats and dyad symmetries. The clustering of the dyad symmetrical elements in some exons, #16 and #17, coincides with the hot spots for structural aberrations of the RB-1 locus previously observed in tumors. The RB-1 gene is divided into at least 27 exons distributed over 200 kbp. Three potential Sp1 binding sites are presented within 600 bp upstream of the translation start site. A DNA fragment containing these Sp1 sites ligated to a promotorless CAT gene can promote its transcription in transfected cell culture.

Base Sequence↗
PubMed1988

Comparative study on the evolution of chloroplast ribosomal 5S RNA of a living fossil plant, Cycas revoluta Thumb.

The complete nucleotide sequence of Cycas revoluta Thunb chloroplast 5 S rRNA was determined. It consists of 122 nucleotides. This is the only known 5 S rRNA sequence in Gymnospermae. It is highly homologous with chloroplast 5 S rRNA of higher plants (92-97%), but less homologous (about 54%) with those of lower plants. There is however 67% homology between Cycas and a procaryote a. nidulans. The chloroplast 5 S rRNAs of Angiospermae are nearly identical with each other (95-97%). S. oligorhize and L. minor have 100% homology among themselves. We have constructed a phylogenic tree of 5 S rRNA sequences from fifteen plant chloroplasts. The result suggests that the emergence of algae occurred at an early stage of plant chloroplast evolution and that green plants originated from green algae. This is in agreement with the classical view and other theories of molecular evolution. However there is no common ancestor in the case of Bryophyta and ferns. Among the Angiospermae, a precise evolutionary process cannot be deduced because the Knuc values among the species are very close to each other.

Base Sequence↗