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Biomedical subjects

W Wu

Publications and source records attributed to W Wu.

At least 361 records · Page 20Linked to original sources
PubMed1996

[16S rRNA gene PCR-SSCP analysis of the reference strains from 15 serovars (14 serogroups) of pathogenic leptospires in China].

The DNAs of reference strains from 15 serovars (14 serogroups) of pathogenic leptospires in China were amplified with 16S rRNA gene primers, and then single-strand conformation polymorphism (SSCP) of the products were analyzed in 12.5% nondenaturing mini polyacrylamide gel (containing 5% glycerol) combining with silver-staining. All products showed two bands on electrophoresis at different parameters of voltage or current and concentration of gel. It proved that serovar lai, serovar canicola, serovar pyrogenes, serovar autumnalis, serovar australis, serovar pomona, serovar linhai, serovar hebdomadis, serovar haemolytica, serovar wolffi and serovar paidjan have the identical pattern (Leptospira interrogans), while serovar javanica, serovar ballum, serovar tarassovi and serovar manhao I belong to another pattern (L. borgpetersenii). The result was consistent with the classification of genetic species by Yasuda et al (1987) and Ramadass et al (1992).

China↗
PubMed1996

[Electrical response recording of cochlear hair cells in vivo].

Intracellular recordings were made on cells of Corti organ from low-frequency region (third turn) of guinea pig cochlea, the recording sites being confirmed by HRP injection and subsequent histology. Response characteristies of the hair cells were studied. The Inner hair cells (IHCs) possessed relatively low resting membrane potentials in contrast to higher ones of OHCs. The receptor potentials from both cell types, in response to tone bursts, consisted of a combination of AC and DC components. For the low-frequency region, the receptor potentials were dominated by AC component. The causes of recording failure were discussed.

Animals↗
PubMed1996

[G-CSF and all-trans retinoic acid-induced leukocytosis].

During the treatment with all-trans retinoic acid (ATRA) for acute promyelocytic leukemia (APL), leukocytosis occured in 33%-75% of the treated cases. ELISA method was used in detecting levels of serum granulocyle colony-stimulating factor (G-CSF) in 47 cases of APL during treatment with ATRA. It was found that the peak of increased serum G-CSF level occurred on the 9th day, and WBC number was highest on the 11th day. After ATRA treatment, both serum G-CSF level and WBC number increased in 68.1% of the cases. In 19.2% of the cases treated, serum G-CSF level was increased but without obvious change in WBC number, and the reverse was true in 12.7% of the cases. Serum G-CSF level was statistically correlated to the number of WBC, promyelocytes and its late stage by Spearman rank correlation analysis.

Adolescent↗
PubMed1996

Changes of endothelin-1 gene expression in rat brains during ischemia and ischemic reperfusion.

OBJECTIVE: The experiment was designed to study the association of cerebral ischemia and reperfusion with endothelin-1 (ET-1) gene expression of rat brains and time-dependent changes of ET-1 gene expression during cerebral ischemia. MATERIALS AND METHODS: Thirty-three male SD rats were divided into dot blot hybridization (n = 27) and in situ hybridization groups (n = 6). The focal cerebral ischemia and reperfusion models were made with suture embolism of middle cerebral artery. Dot blot hybridization groups were redivided into control and ischemic subgroups (ischemia for 0.5, 1, 1.5, 3, 6, 12, 24, 48 and 72 h respectively). In situ hybridization groups were redivided into ischemia and reperfusion groups. After 24 h ischemia and 24 h reperfusion, ET-1 gene expressions were investigated with in situ hybridization and the results were analyzed with IBAS 2000 Image Analysis System. RESULTS: Dot blot hybridization showed that ET-1 mRNA of cerebral cortex and caudate-putamen was increased at 6 h of ischemia and reached peak at 24 h (3.9 and 3.7 fold respectively), and at 72 h of ischemia it remained at high levels (3.5 and 2.1 fold respectively). In situ hybridization showed that the levels of ET-1 mRNA of cerebral cortex and caudate-putamen were also markedly increased both in 24 h ischemia and 24 h reperfusion groups (P < 0.01, P < 0.05 respectively). CONCLUSIONS: ET-1 gene expression in focal ischemic brain tissue were markedly and progressively increased during cerebral ischemia and reperfusion and down-regulation of ET-1 gene expression may be a new approach to the treatment of ischemic cerebrovascular diseases.

Animals↗
PubMed1996

[The changes of vasoactive intestinal peptide somatostatin and pancreatic polypeptide in blood and CSF of acute cerebral infarction patients and the effect of acupuncture on them].

VIP, SS and PP which exist in gastrointestinal tract and CNS might be to play an important role in nervous system as neurotransmitters of neuromediaters. There have been a few of reports about their changes in plasma and CSF in ICVD. The effects of acupuncture, which was used in treatment of ICVD with good efficiency, on VIP, SS and PP have not been known. For researching their changes in ICVD and effects of electro-acupuncture on them, and finding the mechanism of acupuncture in treatment of ICVD, the study was performed. The levels of VIP, SS and PP in 64 patients with acute cerebral infarction were determined. The points of acupuncture were Quchi (LI 12), Waiguan (SJ 5), Huantiao (BG 30), and Zusanli (ST 36). The routine treatment included dextran, nicotinic acid, aspirin, dipyridamole and radix salviae miltiorrhizae composita. The CSF and blood were taken before the begining of treatments and after a course of treatment. The level of VIP, SS and PP were measured by radiommunoassay. Results showed the level of CSF VIP in the patients was significantly lower as compared with controls. The level of plasma SS in the patients was lower, but the difference was not significant as compared with controls, and level of plasma PP in the patients was significantly increased when it was compared with controls. After electro-acupuncture treatment, in patients with good efficiency, CSF VIP recovered to normal level and the levels of plasma and CSF SS were significantly increased, while the level of plasma PP had no significant change. The results suggest that acupuncture might regulate the disturbances of metabolism of VIP and SS in CNS.

Acupuncture Points↗
PubMed1996

[Studies on semen quality in workers exposed to manganese and electric welding].

Three hundred and ten workers were selected to study the effects of manganese and electric welding on male reproductive function, with 211 occupationally exposed to manganess and electric welding fume and 99 controls. Concentrations of manganese and welding fume in the air of the workplace were 0.14-5.5 mg/m3 and 6.5-82.3 mg/m3, respectively. Semen concentrations of manganese, copper, chromium, nickel, and iron in workers employed in electric welding were significantly higher than those in controls. Time from ejaculation to liquefaction of semen in exposed workers was longer than that in controls, and volume of semen, sperm count, viable sperm count and percentage were significantly lower in the exposed workers than in the controls. Stepwise regression analysis suggests a direct toxic effect of manganese on sperm production.

Adult↗
PubMed1996

[Research on the recombinant plasmid pDJH2 of L. interrogans serovar lai: sequencing and alignment with other known bacterial Omp sequence].

The Leptospira whole cell vaccine (LWCV) currently used in China is safe and effective, out the immunity following vaccination with two doses of the fluid medium vaccine is of low order. The duration of immunity conferred by this vaccine is rather short, six months or at most one year. Therefore, it is necessary to develop new generation vaccines against Leptospirosis for the developing world. In this paper we report the sequencing of the insert fragment of pDJH2 from genomic DNA of L. interrogans sevovar lai strain 017 and its alignment with other bacterial omp sequences. A genomic library of Leptospira interrogaans serovar lai strain 017 was constructed with the plasmid vector pUC18. A recombinant plasmid designated pJDH2 was screened from the genomic library. Inserted fragment of pDH2 is 1.9 kb by gel electrophoresis. Immunization/protection was studied in BALB/c mice model. The results showed highly significant difference between pDJH2 and pUC18 (control). Inserted fragment of pDJH2 DNA sequencing was performed by Dr Yan Zhengxin (Max-Planck-Institut for Biology. Tubingen, Germany). Insert fragment was cloned into pBluescript II KS-(stratagene) and sequenced by using AB1 (Applied Bio Systems, Model 373A). Two open reading frames of 565 and 662 nucleotides were identified. There were identifiable initiation codons, terminators, Shine-Dalgano ribosome combining site, Pribnow boxes and Sextama boxes within the 2 sequenced regions. Nucleotide sequences were analysed using Gene Work, a suit of computer program developed by Department of Biochemistry St. Jude Children's Research Hospital Memphis. U.S.A. The results of formatted alignment showed the predicted nucleotide sequence of ORF1 of the serovar lai had significant similarity with ORF2 (49.36%). L. kirschneri ompL1 (49.26%), Borrelia burgdoferi omp (48.97%), Treponema phagedenis omp (47.3%); Salmonella typhimurium ompC(46.87%), Yersinia enterocolitica ompH (46.7%), Leptospira borgpeterseni pfap (46.3%), and Serratia marcescens omp (43.3%). The close relationship of the pDJH2 ORF1 and ORF2 nucleotide sequences from Leptospira kirschneri ompL 1 is apparent. Whether the recombinant pDJH2 will prove useful for vaccine development remains to be tested.

Animals↗
PubMed1996

[Subclones of fragment DNA recombinant rpDJH2 of L. interrogans serovar lai strain 017 and it's expression of high level in E. coli].

Fragment of 1.9 kb recombinant DNA of pDJH2 was linked with vectors pT7-7 and pRSETs. Then they were transformed into E. coli JM109 (DE3) respectively. Expression of subclones was achieved in E. coli JM109 (DE3) with IPTG inducement. SDS-PAGE showed that the molecular weights of products were 68kd and 23 kd respectively. The amount of production seemed to be higher than that of the outer membrane proteins of L. interrogans serovar strain 017 in nature. Immunoblotting of pDJt and pDJrB2 (both are subclones) with the specific antiserum of anti-OMP of L. interrogans serovar lai strain 017 and the experiment of initiative immuno-protection in guinea pigs showed both protein-68 kd and 23 kd might be the antigens of immuno-protection on the outer membrane of L. interrogans serovar lai strain 017.

Animals↗
PubMed1996

[Medical imaging research on idiopathic hemifacial spasm].

In order to have a medical imaging examination for idiopathic hemifacial spasm before surgery, we designed a new method by using vertebroarterial DSA and vertebroarterial CTA based on an aired cisternapontis, 36 patients were examined since 1989 and the compression of the facial nerve from brain stem to porus acousticus internus was showed clearly in all the cases. The arteries responsible for the compression were cerebellar inferior posterior (55.6%), cerebellar inferior anterior (44.4%), auditory internus (25.0%) and vertebroarterial (11.1%), 36% of all the cases had more than one responsible arteries, 22.2% cases had only one compression point, 38.9% had two points, 25.0% had 3 and 13.9% had more. 85.7% of the compression points located in the root zone and 14.3% near the porus acousticus internus. 24 cases were treated with decompression surgery, it indicated that the compression conditions just met the medical imaging examinationg results. After surgery the symptom disappeared in 23 cases and remarkably released in one case with no death case. We believed that this method might be helpful to idiopathic hemifacial spasm decompression surgery and other surgeries in the CP angle.

Adult↗
PubMed1996

[Studies on oral sustained-release microspheres of nifedipine].

Nifedipine has been incorporated into Eudragit RL microspheres by the emulsion solvent-evaporation process using an acetone/liquid paraffin system. The drug in the Eudragit RL microspheres was present in either molecular dispersion or amorphous state. The drug release profile from microspheres conformed to the Higuchi equation. The microspheres were stable under different storage conditions for six months with respect to drug content, dispersing state and release profile. The in vivo results in eight healthy volunteers showed that the relative bioavailability of the nifedipine sustained-release microspheres against commercial retard tablet as a control was 102.5%, and the microsphere formulation was bioequivalent to the retard tablet. Significant in vitro and in vivo correlation was also found for the microspheres.

Adult↗
PubMed1995

Rescue of adult mouse motoneurons from injury-induced cell death by glial cell line-derived neurotrophic factor.

Glial cell line-derived neurotrophic factor (GDNF) has been shown to rescue developing motoneurons in vivo and in vitro from both naturally occurring and axotomy-induced cell death. To test whether GDNF has trophic effects on adult motoneurons, we used a mouse model of injury-induced adult motoneuron degeneration. Injuring adult motoneuron axons at the exit point of the nerve from the spinal cord (avulsion) resulted in a 70% loss of motoneurons by 3 weeks following surgery and a complete loss by 6 weeks. Half of the loss was prevented by GDNF treatment. GDNF also induced an increase (hypertrophy) in the size of surviving motoneurons. These data provide strong evidence that the survival of injured adult mammalian motoneurons can be promoted by a known neurotrophic factor, suggesting the potential use of GDNF in therapeutic approaches to adult-onset motoneuron diseases such as amyotrophic lateral sclerosis.

Animals↗
PubMed1995

Observation of a second substrate radical intermediate in the reaction of lysine 2,3-aminomutase: a radical centered on the beta-carbon of the alternative substrate, 4-thia-L-lysine.

Lysine 2,3-aminomutase from Clostridia catalyzes the interconversion of lysine and beta-lysine by a mechanism in which four organic radicals are postulated as intermediates. One of the intermediates has been identified as the alpha-radical of beta-lysine in imine linkage to pyridoxal phosphate (PLP) [Ballinger, M. D., Frey, P. A., & Reed, G. H. (1992) Biochemistry 31, 10782-10788]. We report here the observation of another of the four putative radical intermediates in the reaction of the alternative substrate, 4-thia-L-lysine (S-2-aminoethyl-L-cysteine). 4-Thialysine is a substrate for lysine 2,3-aminomutase. The Km of 4-thialysine is similar to that for lysine, and the Vm is approximately 3% of that for lysine. Upon mixing 4-thialysine with the activated enzyme in the presence of the required cofactor S-adenosylmethionine, followed by freeze-quenching with liquid N2 in the steady state, a strong EPR signal centered at g = 2.003 is observed. This signal exhibits strong hyperfine splitting due to the presence of 13C at carbon-3 of 4-thialysine, and the EPR pattern is narrowed upon the substitution of deuterium at carbon-3. The hyperfine interactions show that the unpaired electron is centered on carbon-3 of 4-thialysine. The hyperfine pattern in the EPR spectrum is also simplified by the use of 4-thia[5,6-2H4]lysine as the substrate, showing either that the spin is partially delocalized through the sulfur intervening between carbons-3 and -5 or that the conformation is such that protons at carbon-6 are close to carbon-3.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Isomerases↗
PubMed1995

Induction of nitric oxide synthase and motoneuron death in newborn and early postnatal rats following spinal root avulsion.

It is well established that immature motoneurons are more vulnerable to axonal injury than the adult ones. Many previous studies used distal axonal injury, such as sciatic nerve transection, to examine the response of immature motoneurons to injury. In the present study, a more severe injury, spinal root avulsion, was performed in newborn and early postnatal rats, and the response of immature spinal motoneurons to the injury was observed. In newborn rats, root avulsion causes motoneuron loss which is similar to that of previous studies by distal axonal injury. During the early postnatal development, motoneuron loss in immature rats is greater following root avulsion when compared to cell loss following distal axonal injury at any given age. Following root avulsion, nitric oxide synthase (NOS) is induced in injured immature motoneurons. The induction and accumulation of NOS in injured motoneurons is much more rapid in the immature animals than in the adult, which is coincident with the more rapid motoneuron loss in the immature animals. Results of the present study indicate an involvement of NOS in neuronal degeneration. However, the precise role of NOS in the response of motoneurons to axonal injury is not clear and needs to be further studied.

Animals↗
PubMed1995

Position-dependent variegation of globin transgene expression in mice.

Expression of genes in eukaryotes has commonly been analyzed in a whole tissue, and levels of expression have been interpreted as the result of equivalent rates of transcription in every cell. We have produced transgenic mouse lines that express beta-galactosidase under the control of globin promoters linked to the major tissue-specific regulatory element of the alpha-globin locus, which permits the analysis of transgene expression in individual red blood cells. We find that expression of the transgene within all mouse lines is heterocellular. Individual cells either do not express the transgene at all or express it at a level characteristic of that line. The number of beta-galactosidase-expressing cells varies greatly between different lines of transgenic mice at any defined stage of development, but within a transgenic line, individual mice have strikingly similar numbers of expressing cells. This suggests that the degree of heterocellular expression is determined by the site of integration, as is seen in position-effect variegation.

Animals↗
PubMed1995

Defects in primer-template binding, processive DNA synthesis, and RNase H activity associated with chimeric reverse transcriptases having the murine leukemia virus polymerase domain joined to Escherichia coli RNase H.

The RNase H domain of murine leukemia virus (MuLV) reverse transcriptase (RT) was replaced with Escherichia coli RNase H, and the effect on RNase H activity and processive DNA synthesis was studied, using RNA-DNA hybrids containing sequences from the MuLV polypurine tract (PPT). Two chimeric RTs, having the entire polymerase domain or all but the last 19 amino acids, were expressed. In both cases, these RTs made multiple cuts in PPT-containing substrates, whereas wild-type cleavages occurred primarily at sites consistent with the distance between the polymerase and RNase H active sites. Primer extension assays performed with the chimeric RTs, an RNase H-minus RT, and wild-type showed that the presence of a wild-type viral RNase H domain facilitates processive DNA synthesis. When wild-type RT was bound to primer-template, two retarded bands could be detected in band-shift assays. In the absence of primer extension, a high proportion of enzyme-bound primer-template was associated with the faster-migrating band, whereas with DNA synthesis, more of the bound radioactivity was in the super-shifted complex. This suggests that the super-shifted complex contains the active form of RT. The mutant RTs were deficient in formation of this complex, but the chimeric RTs were somewhat less defective than the RNase H-minus mutant. Our results demonstrate that in the wild-type enzyme, the RNase H domain is required to stabilize the interaction between RT and primer-template.

Base Sequence↗
PubMed1995

Localization of the alpha 7 integrin gene (ITGA7) on human chromosome 12q13: clustering of integrin and Hox genes implies parallel evolution of these gene families.

Expression of the alpha 7 integrin gene (ITGA7) is developmentally regulated during the formation of skeletal muscle. Increased levels of expression and production of isoforms containing different cytoplasmic and extracellular domains accompany myogenesis. To determine whether a single or multiple alpha 7 genes underlie the structural diversity in this alpha chain that accompanies development, we have examined the rat and human genomes by Southern blotting and in situ hybridization. Our results demonstrate that there is only one alpha 7 gene in both the rat and the human genomes. In the human, ITGA7 is present on chromosome 12q13. Phylogenetic analysis of the integrin alpha chain sequences suggests that the early integrin genes evolved in two pathways to form the I-integrins and the non-I-integrins. The I-integrin alpha chains contain an additional sequence of approximately 180 amino acids and arose as a result of an early insertion into the non-I-gene. The I-chain subfamily further evolved by duplications within the same chromosome. The non-I-integrin alpha chain genes are localized in clusters on chromosomes 2, 12, and 17, and this closely coincides with the localization of the human homeobox gene clusters. Non-I-integrin alpha chain genes appear to have evolved in parallel and in proximity to the Hox clusters. Thus, the Hox genes that underlie the design of body structure and the Integrin genes that underlie informed cell-cell and cell-matrix interactions appear to have evolved in parallel and coordinate fashions.

Amino Acid Sequence↗