Biomedical subjects

W Xu

Publications and source records attributed to W Xu.

At least 505 records · Page 28Linked to original sources

PubMed1994

[Influence of cooling motor cortex on the inhibitory effect of stimulation of SII on nociceptive responses in ILN neurons].

Fibers from the cortical somatosensory area II (SII) or motor cortex (MCtx) to intralaminar nuclei (ILN) have been proven to exist, and SII was found to be connected with MCtx by cortico-cortical fibers. The present work was undertaken to study whether MCtx participated in SII producing descending modulation of ILN. All experiments were performed on sodium pentobarbitone anaesthetised cats. Single unit activities of ILN neurons were extracellularly recorded by glass microelectrodes. The effects of stimulating SII on nociceptive responses of ILN neurons were observed before and after cooling MCtx. The nociceptive responses of ILN neurons were attenuated by stimulating SII. There was a statistically significant difference at 0'-2' after the stimulation (n = 14, P < 0.05). The inhibitory effect of stimulating SII was reduced after cooling MCtx (19 degrees C-20 degrees C) in 8 neurons, and abolished in other neurons when the temperature was below 18 degrees C. MCtx was involved in SII producing descending modulation of ILN.

Animals↗

PubMed1994

[Practical value of IgG index and IgG synthesis rate in multiple sclerosis].

IgG index and IgG synthesis rate were determined in 40 patients with multiple sclerosis (MS) (including 21 patients treated with corticosteroid), 20 patients with other neurological diseases (OND) and 22 normal controls, by Beckman Immunochemistry system II made in USA. The practical value of IgG index and IgG synthesis rate were evaluated by means of the method of clinical epidemiology. The results showed that in the diagnosis of MS the sensitivity, specificity and positive result likelihood ratio (PRLR) of IgG index were 63%, 65% and 1.80, respectively; those of IgG synthesis rate were 50%, 65% and 1.43, respectively. In the further observation, however, it was found that the sensitivity and PRLR were 84% and 2.4 in IgG index, 79% and 2.26 in IgG synthesis rate, after the influence of corticosteroid was excluded. In addition, in judging whether there was organic damage in central nervous system, the specificities and PRLRs of IgG index and IgG synthesis rate were 100% and infinitely great, respectively. The above results are discussed in this article.

Adolescent↗

PubMed1994

[Molecular epidemiological characteristics of Salmonella typhi strains isolated in China. I. Analysis of Salmonella typhi strains isolated in China by multilocus enzyme electrophoresis].

Multilocus enzyme analysis by polyacrylamide gel electrophoresis (PAGE) was used to analyse 335 isolates of S. typhi from several provinces where high morbidity of typhoid fever was observed in recent years. We analysed 7 metabolic enzymes encoded by chromosome. The results showed that all the enzyme loci were polymorphic. The average alleles per locus was 7.4 (2-19): the mean genetic diversity per locus was 0.498 (0.198 0.883). There were 147 distinctive electrophoretic types (ETs) in 335 isolates. With cluster analysis by the average-linkage method, we found that there were 22 subclones, 12 clones among all isolates studied. Most isolates in 1988 from both Jiangsu and Zhejiang provinces belonged to one clone; the isolates from Guangxi Province in 1990 and parts of Hubei isolates belonged to one clone; the isolates from Hunan and Guizhou provinces during several-year period were homogeneous. However, the isolates from Xinjiang Autonomous Region were remarkebly different from other provinces, belonging to a particular clone. We also observed that the isolates from an outbreak or epidemic were from a one subclone.

Alleles↗

PubMed1994

[Involvement of glutamate in corticofugal modulation of intralaminar nuclei from SII via motor cortex in acupuncture analgesia].

The present experiments were designed to study the effect of glutamate on cortical somatosensory area II (S II) producing descending modulation of intralaminar nuclei (ILN) via the motor cortex (MCtx) in acupuncture analgesia. The glutamate antagonist glutamate diethylester (GDEE) or saline was topically applied at MCtx in 17 cats. Single unit activities of ILN neurons were extracellularly recorded. The results were as follows: 1. The nociceptive responses of ILN neurons were attenuated by stimulating S II after topical administration of saline at MCtx. However, the inhibitory effect of stimulating S II in the same neurons was reduced after application of GDEE. There was a significant difference at 0'-1' after the stimulation between the two groups (n = 10, P < 0.05). 2. The inhibitory effect of electroacupuncture (EA) on nociceptive responses was reduced after topical application of GDEE, while marked inhibition was shown at 0'-10' after cessation of EA in the saline control group (n = 11, P < 0.05). The results, together with the finding that the majority of S II neurons could be activated by EA, showed that glutamate released from S II to MCtx might be involved in corticofugal modulation of ILN from S II via MCtx in acupuncture analgesia.

Acupuncture Analgesia↗

PubMed1994

[Iontophoretic atropine attenuates the inhibitory effect of stimulating SmI on nociceptive responses of pf neurons].

Using the techniques of multimicropipette and iontophoresis, we observed whether ACh was involved in the cortical descending modulation of Pf neurons in rats. It was shown that the inhibition elicited by stimulation of the sensorimotor area (SmI) was attenuated after microiontophoretic atropine and that the nociceptive responses of Pf neurons were obviously reduced by microiontophoretic ACh. Therefore, it suggests that ACh may be considered as one of the neurotransmitters involved in the descending modulation of pain.

Acetylcholine↗

PubMed1994

[Treatment of hypertensive intracerebral hematoma by CT-directed puncture aspiration and negative-pressure drainage--analysis of 120 cases].

Puncture aspiration and negative-pressure drainage have been performed in 120 patients with hypertensive intracerebral hematoma. The results demonstrated that the CT-directed location method designed by us, based on Matsumoto and Hondo, s location method, is simple, practicable, very accurate and less. When intracranial CT and clinical manifestations of hematoma are comprehensively analyzed, an operative indication can be correctly selected. Depending on CT manifestations and pathological changes, the selected operative time is 48h or so. Of the 120 patients which underwent this operation, only 31 have died. The mortality rate is 25 percent. The effect of the therapy is satisfactory.

Adult↗

PubMed1994

Cloning and high level expression of gene encoding ES antigen from Trichinella spiralis muscle larvae.

The partial structure gene encoding ES antigen derived from Trichinella spiralis (TSP) muscle larvae was cloned, characterized, and expressed in E. coli. The target DNA (0.7 kb) was directly obtained from the TSP total RNA by using RNA PCR technique. Based on the analysis with the RE digestion, the fragment was cloned into the fusion expression vector pEX31C. It was shown that a kind of 37kDa fusion protein was expressed in E. coli containing the recombinant plasmid by SDS-PAGE electrophoresis. The expressed protein was over 22% of the total cell protein, and it was aggregated in the form of inclusion bodies in E. coli. The purified protein could be recognized in ELISA both by sera from swine-infected with TSP and by the monoclonal antibody against TSP. These findings suggest that the recombinant protein is a potentially valuable antigen both for immunodiagnosis and vaccine development of trichinellosis.

Animals↗

PubMed1994

[Effects of anisodine on respiratory center].

Anisodine (Ani), a new selective M receptor blocking agent, was isolated from Scopolia tangutica in China. The structure of Ani is similar to scopolamine. Ani (2.5, 5 mg.kg-1 i.v., or 0.6 mg.kg-1 icv) increased the rate of phrenic nerve discharges (PND), while the time of inspiration and expiration, and the spikes in each PND were reduced in urethan-anesthetized rats. In urethan-anesthetized rabbits, Ani (2.5 mg.kg-1 i.v., or 0.2 mg.kg-1 applied onto obex) increased the rate of PND. In tubocurarine-pretreated and artificially ventilated rabbits, Ani (2.5 mg.kg-1 i.v., or 0.2 mg.kg-1 applied onto obex) increased the rate of inspiratory neurone firing in nucleus tractus solitarius. Oxotremorine (40 micrograms.kg-1 i.v.) antagonized the Ani effects. Ani (2.5 mg.kg-1 i.v.) partially antagonized the respiratory depression induced by morphine. These results provide the evidence that Ani stimulates the respiratory center through cholinergic M pathway and there may be some neuronal interaction between cholinergic and opiate receptors in the control of respiratory center.

Animals↗

PubMed1994

Serotonin receptor subtypes in spinal antinociception in the rat.

The aim of the present study was to clarify the subtypes of serotonin (5-HT) receptors involved in spinal antinociception in the rat. 1) Intrathecal (i.t.) injection of 5-HT (25-200 micrograms) produced a dose-dependent increase in tail-flick latency. 2) Intrathecal injection of fluoxetine, a 5-HT uptake blocker (25-40 micrograms), resulted in a bell-shaped dose-related antinociception with peak effects occurring at 10 micrograms. 3) A bell-shaped antinociceptive effect was obtained by i.t. injection of the 5-HT1A agonist (+)-hydroxy-2-(di-N-propylamino)tetralin (0.25-2 micrograms), with the maximal effect occurring at 0.5 micrograms, which can be prevented by the 5-HT1A antagonist spiperone (25 micrograms i.t.). 4) A similar dose-response curve was obtained following the i.t. injection of the 5-HT1B agonist 1-[3-(trifluoromethyl)phenyl]-piperazine maleate (1-125 micrograms) with the maximal effect observed at 25 micrograms. 5) Neither the 5-HT2 agonist (+/-)-alpha-methyl-5-HT-maleate nor the 5-HT3 agonist (+/-)-2-methyl-5-HT-maleate produced significant antinociceptive effects at doses up to 50 micrograms. Spontaneous tail-flicks emerged at doses higher than 50 micrograms. 6) The antinociceptive effect induced by 5-HT (200 micrograms i.t.) could be attenuated dose-dependently either by the 5-HT1A antagonist spiperone (5 and 25 micrograms i.t.) or by the 5-HT1C/2 antagonist mianserin (0.5-50 micrograms i.t.), but not by the 5-HT2 antagonist 1-(1-naphthyl)piperazine hydrochloride or the 5-HT3 antagonist 3-tropanyl-indole-3-carboxylate.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Hydroxy-2-(di-n-propylamino)tetralin↗

PubMed1994

[Application of multilocus enzyme electrophoresis in studies of taxonomy and population genetics of S. typhi in Xinjiang].

Multilocus enzyme electrophoresis (MEE) was employed to study the genotype taxon and population genetics of 154 isolates of S. typhi from Xinjiang in recent 11 years. Seven kinds of enzymes were examined and determined. One hundred and fifty-four strains of S. typhi were classified into 69 electroretic types (ETs) and 10 clones (CLa-CLj). Among those 154 strains 80 epidemic isolates belonged to 21 ETs and 3 clones (CLe, f, j). ET17, 20, 21, 24, 26, 27 were the main ETs (61.30%), and CLf was the dominant clone (95.00%). Seventy-four non-epidemic isolates belonged to 48 ETs and 9 clones (CLa, b, c, d, f, g, h, i, j), no obvious dominant ET was found in them, and the main clone CLh accounted for 43.30%. It demonstrated that both outbreak and sporadic epidemics could be caused by many strains of ETs and clones, but the distribution of the former ETs was more concentrated and the preponderance of clones was more obvious. The analyses on structure of population genetics indicated that all of 7 enzymes were polymorphic. Genetic diversity among the enzyme loci was quite high, with an average of 0.35 per locus (H). The average number of alleles per locus (h) was 6.14. There was no significant difference in h or H between the isolates of different sources (P > 0.05). It was clear that S. typhi of different sources in Xinjiang were originated from the same population. The results also showed that there was a dominant allele in every enzyme locus. Natural selection was the main role in the evolution of S. typhi.

Alleles↗

PubMed1994

Detection of point mutations in exon 2 of the G6PD gene in Chinese G6PD variants.

In the past few years, a total of 6 different mutations of the G6PD gene have been reported in China. One of these, the C6 mutation (A95-->G), accounted for about 15.4% of the Chinese G6PD variants. In order to develop a strategy for rapid detection of mutation-containing exons of the G6PD gene, we applied the single-strand conformation polymorphism (SSCP) technique to the detection of mutations in exon 2 of this gene. We observed four patients with abnormal migration patterns of the exon 2 band among 20 cases of G6PD variants. Direct PCR sequencing confirmed a T to C substitution in exon 2 that has previously been reported. This procedure is therefore of particular importance for the rapid detection of mutation-containing exons in the G6PD gene.

Base Sequence↗

PubMed1993