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Biomedical subjects

W Wang

Publications and source records attributed to W Wang.

At least 379 records · Page 21Linked to original sources
PubMed2001

[A study on the relationship between deciduous tooth caries in pre-school children and their neonatal conditions].

OBJECTIVE: This study was designed to examine whether the neonatal conditIon might be related to the caries of deciduous teeth in pre-school children. METHODS: 1000 children from 3 years old to 6 years old in Chengdu were surveyed, and 260 children with dmft > or = 6 and 260 caries-free children were chosen. Data was collected by 200 pairs of useful questionnaire from their parents and analyzed by using logistic regression analysis and chi 2 test. RESULTS: The neonatal condition was closely related with incidence rates of deciduous caries in pre-school children (P < 0.05). The incidence rate of children with premature delivery was higher than that with full-term normal delivery (P < 0.05). No significant difference was showed in children with full-term normal delivery and children with dystrophy (P < 0.05). CONCLUSION: There should be emphasis on the children with premature delivery in caries preventive cares.

Child↗
PubMed2001

[Gentamicin for the transtympanic treatment of Menière's disease].

OBJECTIVE: This study described the method and efficacy of intratympanic gentamicin injection for obstinated, incapacitated Meniere's disease. METHOD: It is a prospective study. Patients selected had classic unilateral Meniere's disease. All had preinjection audiometric and electronystagmography. Injection was accepted every two or three days. It is important to direct the therapy by observing the symptoms closely and checking the audiometric and electronystagmography whenever necessary. RESULT: All the 12 cases undergone the treatment were followed up from 2 to 9 years. According to the criterion of Chinese Medical Association of ENT, the vertigo of Meniere's disease was evaluated. A (completed control): 10 cases; B (largely control): 2 cases. 4 cases said their tinnitus disappeared and 3 cases felt it improved. Hearing loss and vibration illusion vision are two complications. CONCLUSION: The methods is simple, useful and safe, the effect of which is similar to vestibular neurectomy. It is the first choice therapy suitable to Meniere's disease patients, which symptoms keep unchanged after medical treatment or failed in surgery.

Adult↗
PubMed2001

[Cloning and phylogenetic analysis of hepatitis-associated TT virus subgenome].

Polymerase chain reaction (PCR) was utilized for the DNA amplification from transfusion transmitted virus (TTV) positive serum samples. Five TTV DNA fragments, overlapped about 90% of the genome, were amplified by long template PCR for the generation of TTV subgenome. Recombinant plasmids were obtained by directly inserting PCR products into pT-Adv vector, and DNA sequence analyses showed they were TTV DNA fragments. By using specific restriction enzymes, five TTV DNA fragments were ligated into a TTV DNA subgenome clone and named as TTV021. TTV021 has been deposited in GenBank database with the accession number AF254410. The results of computer analyses showed that TTV021, 3472 nt long, contains two open reading frames (ORF1, 785 aa; ORF2, 146 aa). Identity alignments between TTV021 and other TTV isolates indicated several high conserved regions existed. Phylogenetic analysis of 356 nt from TTV021 suggested that the isolate has close evolutionary relationship with CHN1 (type 1a), but has far relation with other TTV isolates.

Circoviridae↗
PubMed2001

[Inhibitory effects of beta-carotene on hepatic cancer cell line SMMC-7721].

The inhibitory effect of beta-carotene on the proliferation of hepatic cancer was studied. Cells from a hepatic cancer cell line SMMC-7721 were incubated in culture media with 20, 40 and 80 mumol/L beta-carotene for 12, 24 and 48 h respectively. MTT test, Trypan blue exclusion test and DNA gel electrophoresis were used. The results of MTT test revealed that beta-carotene (20-80 mumol/L) could inhibit the proliferation of SMMC-7721 cells in a dose-dependent manner. DNA gel electrophoresis showed that the apoptosis of hepatic cancer cells could be induced by beta-carotene (40 mumol/L). It is concluded that the proliferation of hepatic cancer cells inhibited by beta-carotene, probably through interfering DNA metabolism and inducing cell apoptosis.

Antineoplastic Agents, Phytogenic↗
PubMed2001

[Cloning and identification of an unknown gene encoding 10.6 kDa protein of Schistosoma japonicum].

OBJECTIVE: To screen a new schistosome vaccine candidate. METHODS: Schistosoma japonicum adult cDNA library was screened using sera from immune rabbits vaccinated with irradiated cercariae and monoclonal antibodies against membrane antigen of S. japonicum schistosomula. Three different fragments of S. japonicum cDNA genes were cloned into pGEM-T vector. The sequences of the inserts were determined using an automatic DNA sequencer and were analysed using Blast program. One of the unknown genes (B8) was selected and its ORF sequence (291 bp) was subcloned into eukaryotic expression vector. The recombinant plasmids were identified by restrictive enzymes and PCR amplification. The positive recombinant plasmids (pBK/SjB8) were transformed into host bacteria XL1-blue, and were then induced by IPTG for expression. SDS-PAGE and Western blotting analysis of total cellular protein from the bacteria were performed to detect the gene products. RESULTS: The results demonstrated that ORF of SjB8 gene was subcloned into the plasmid pBK-CMV and could express as fusion protein in XL1-blue. The results of SDS-PAGE and Western-blot also showed that the molecular weight of the fusion protein with 3 kDa beta-galactosidase was approximately 13.6 kDa and the actual molecular weights of the SjB8 was 10.6 kDa. The expressed fusion product of pBK/Sj-B8 could be recognized by immune serum and McAb. CONCLUSION: A new gene of S. japonicum vaccine candidate (SjB8) was cloned into eukaryotic expression vector pBK-CMV and could express 10.6 kDa schistosome protein. The results provide foundation for further study of the protein for its possibility as candidate vaccine.

Animals↗
PubMed2001

[A simple coupled instrument for hyperthermia].

In this paper, we present a temperature-controlled watercycling coupled instrument, which changes from the air-couple of the applicator to water-cycling couple when superficial heating is given. This instrument in combination with the characters of the present microwave device, has brought about the changes of coupling media without changing the structure of the applicator.

Equipment Design↗
PubMed2001

Epidermal growth factor prevents increased permeability and bacterial translocation in rats with acute pancreatitis.

OBJECTIVE: To evaluate the effects of epidermal growth factor (EGF) on intestinal permeability and bacterial translocation in rats with acute pancreatitis during total parenteral nutrition (TPN). METHODS: Thirty-two male Sprague-Dawley rats that underwent injection of 3.5% sodium taurocholate solution into the pancreatic duct were randomly divided into one of the following two groups: (1) received only TPN (control group) or (2) received TPN with EGF at a dose of 0.2 mg x kg(-1) x day(-1) (Egf group). On fifth day of total parenteral nutrition, samples from mesenteric lymph nodes, pancreas, liver and spleen were harvested for cultures. Water, protein and DNA content in jejunal mucosa were determined. D-xylose and fluorescein isothiocyanate (FTC)-dextran were instilled into the lumen of a ligated segament of small intestine. Thirty minutes later, superior mesenteric vein D-xylose and plasma FITC-dextran concentration were measured. RESULTS: Positive cultures in liver and spleen, as well as FITC-dextran concentration in the Egf group were significantly lower than in the control group. Protein and DNA content in jejunal mucosa in the Egf group were significantly higher than in the control group. CONCLUSION: The results indicate that EGF may prevent increased intestinal permeability and bacterial translocation in rats with acute pancreatitis during TPN.

Acute Disease↗
PubMed2001

Surgical treatment of malignant esophageal tumors in PUMC Hospital.

To study how to prolong the postoperative survival time of the patients with malignant esophageal tumors. The clinical data of 1098 patients with malignant esophageal tumors from 1961 to 1992 were retrospectively analyzed. The deletion of fragile histamine triplet (FHIT) gene (a tumor suppressor gene) in 30 fresh esophageal samples obtained in 1996 was detected with PCR and RT-PCR method. The resectability was raised gradually and the operative morbidity and mortality decreased year by year, but there was no significant improvement on the postoperative 5-year survival rate. Delayed diagnosis and irradical resection influenced the long-term survival. The deletion of cDNA of FHIT gene was 64. 2% in esophageal cancer and 20% in the resected margin of the cancer. We believe that high-grade atypical hyperplasia in esophageal epithelium and deletion of FHIT gene in esophageal cancer and its resected margin are pathological and molecular markers for early diagnosis of esophageal cancer respectively, and the latter may be one of the molecular markers for the resection. Early diagnosis and treatment, radical, resection, and postoperative nutritional support are very important for the improvement of the postoperative survival time of the patients.

Acid Anhydride Hydrolases↗
PubMed2001

[A retroviral bicistronic strategy for efficient coexpression of ALDH1 and mdr1].

OBJECTIVE: To elucidate the feasibility of coexpression of human class 1 aldehyde dehydrogenase (ALDH1) and multidrug resistance gene (mdrl) by a retroviral bicistronic vector containing an internal ribosome entry site (IRES). METHODS: The constructed retroviral bicistronic vector G1Na-ALDH1-IRES-mdr1 (G1Na-AIM) was transduced into amphotropic packaging cells PA317 by electroporation. Selection was performed by using 15 ng/ ml vincristine. The titer of retrovirus was elevated by ping-pong transduction. K562 cells were transfected with retroviral producing cell supernatant. The integration of the transferred gene and its expression and the efficiency of transfection were determined by polymerase chain reaction (PCR), Southern blot, MTT assay, flow cytometry (FCM) and colony forming assay, respectively. RESULTS: The retroviral titer reached 1.0 x 10(5) cfu/ml in the supernatant of the PA317/ AIM cells after cross-infection with ecotropic GP + E86 cells. The transfected K562 cells exhibited a 3 - 10-fold increase of resistance to 4-hydroperoxycyclophosphamide (4-HC) and vincristin (VCR) and 62% of them expressed P-gp. The integration of both ALDH1 and mdr1 was confirmed by PCR and Southern blot analysis. CONCLUSION: The IRES containing bicistronic retroviral vector allows functional coexpression of two different kinds of drug resistance genes. This strategy could be applicable to the transfer of other combinations of drug resistance gene and dominant selection of transfectant cells in vivo.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed2001

[An epidemiological study of spongiform leucoencephalopathy among heorin abusers].

OBJECTIVE: To understand the distribution and related risk factors of heroin spongiform leucoencephalopathy among drug users in coastland of Guangdong Province. METHODS: A cross-sectional study was conducted in four thousand four hundred and twenty eight drug users from eighteen detoxification organizations in six cities on coastland of Guangdong, using clustered random sampling methods. The six cities are Chaoyang (714), Heyuan (462), Shantou (572), Huidong (1286), Guangzhou (871) and Zhanjiang (523) and heroin abuse was considered serious in these cities. Questionnaire was used to collect the data on sex (man 3632, 82 percent; woman 795, 18 percent), age (minimum 15y, maximum 54y), duration of using heroin (minimum 1 month, maximum 150 months), daily dosage (minimum 0.02 g, maximum 6.0 g) and manner of using heroin. In addition, the neurological examination was taken in all of them and cerebral MRI was carried out in those with signs of cerebellar ataxia. RESULTS: Results showed that the total incidence of heroin spongiform leucoencephalopathy in six cities is 3.16 per thousand. Poisson regression analysis showed that the incidence was related to residential areas. In comparison with other cities, there are higher incidences in Chaoyang and Heyuan. Our investigation also showed that all the patients with this disease used heroin by inhaling the pyrolysate. The incidence of heroin spongiform leucoencephalopathy was unrelated to the daily inhaling amount of heroin and the duration of inhaling heroin. No differences could be observed between the groups of different age and sex. CONCLUSIONS: Spongiform leucoencephalopathy after inhalation of heroin is a rare complication and has never been reported in mainland of China before. The lesions are symmetrical and spongiform, but not necrotic and the cerebellum is invariably involved--a feature consistent with the clinical presentation that begins with ataxia. Cerebral CT showed symmetrical non-enhancing hypodense areas in both cerebellar hemispheres. Cerebral MRI showed the corresponding areas with decreased signal intensity on T1 weighted images and increased signal intensity on T2 weighted images. There was no contrast enhancement. When it occurs, several cases are affected as a small epidemic. It is suggested that the aetiology is related to the heroin batch and could perhaps be a toxic effect of a substance which came from heroin pyrolysis.

Administration, Inhalation↗
PubMed2000

Crystal structure of an intracellular protease from Pyrococcus horikoshii at 2-A resolution.

The intracellular protease from Pyrococcus horikoshii (PH1704) and PfpI from Pyrococcus furiosus are members of a class of intracellular proteases that have no sequence homology to any other known protease family. We report the crystal structure of PH1704 at 2.0-A resolution. The protease is tentatively identified as a cysteine protease based on the presence of cysteine (residue 100) in a nucleophile elbow motif. In the crystal, PH1704 forms a hexameric ring structure, and the active sites are formed at the interfaces between three pairs of monomers.

Amino Acid Sequence↗
PubMed2000

Ski represses bone morphogenic protein signaling in Xenopus and mammalian cells.

The bone morphogenic proteins (BMPs) play important roles in vertebrate development. In Xenopus, BMPs act as epidermal inducers and also as negative regulators of neurogenesis. Antagonism of BMP signaling results in neuralization. BMPs signal through the cell-surface receptors and downstream Smad molecules. Upon stimulation with BMP, Smad1, Smad5, and Smad8 are phosphorylated by the activated BMP receptors, form a complex with Smad4, and translocate into the nucleus, where they regulate the expression of BMP target genes. Here, we show that the Ski oncoprotein can block BMP signaling and the expression of BMP-responsive genes in both Xenopus and mammalian cells by directly interacting with and repressing the activity of BMP-specific Smad complexes. This ability to antagonize BMP signaling results in neuralization by Ski in the Xenopus embryo and blocking of osteoblast differentiation of murine W-20-17 cells. Thus, Ski is able to repress the activity of all receptor-associated Smads and may regulate vertebrate development by modulating the signaling activity of transforming growth factor-beta family members.

Animals↗
PubMed2000

Bioavailability of sediment-bound Cd, Cr and Zn to the green mussel Perna viridis and the Manila clam Ruditapes philippinarum.

We assessed the degree to which Cd, Cr and Zn bound with sediment were assimilated by the green mussel Perna viridis and the Manila clam Ruditapes philippinarum. The influences of the metal concentration in the sediment, the presence of phytoplankton, and the oxidation condition of the sediment on metal assimilation were examined. No major difference was found for metal assimilation efficiency (AE) in sediment with different metal concentrations, except for Cd in the green mussels, in which the AE increased by 1.7x when the Cd concentration in sediment was elevated to 15x the natural background level. The higher assimilation of Cd with increasing Cd load in ingested sediment may be due to the higher desorption of Cd in the acidic gut of the bivalves. Both mussels and clams assimilated metals at a higher efficiency from the diatom diet (Thalassiosira pseudonana) than from inorganic sediment particles. The presence of algal particles had little influence on metal assimilation from ingested sediment, and conversely, the presence of sedimentary particles had little effect on metal assimilation from ingested diatom (except for Cd in the mussels). In the mussels, AEs were higher from oxic sediment than from anoxic sediment by 3.1x for Cd, 2.0x for Cr, and 1.4x for Zn, and in the clams AEs were higher from oxic sediment by 2.8x for Cd, 2.0x for Cr, and 2.0x for Zn. Our study suggested that metals associated with anoxic sediment can be potentially available to marine bivalves, and that metal AEs determined for a single diet were probably not affected by the presence of other food particles.

Journal Article↗
PubMed2000

The human SWI/SNF-B chromatin-remodeling complex is related to yeast rsc and localizes at kinetochores of mitotic chromosomes.

The SWI/SNF family of chromatin-remodeling complexes facilitates gene expression by helping transcription factors gain access to their targets in chromatin. SWI/SNF and Rsc are distinctive members of this family from yeast. They have similar protein components and catalytic activities but differ in biological function. Rsc is required for cell cycle progression through mitosis, whereas SWI/SNF is not. Human complexes of this family have also been identified, which have often been considered related to yeast SWI/SNF. However, all human subunits identified to date are equally similar to components of both SWI/SNF and Rsc, leaving open the possibility that some or all of the human complexes are rather related to Rsc. Here, we present evidence that the previously identified human SWI/SNF-B complex is indeed of the Rsc type. It contains six components conserved in both Rsc and SWI/SNF. Importantly, it has a unique subunit, BAF180, that harbors a distinctive set of structural motifs characteristic of three components of Rsc. Of the two mammalian ATPases known to be related to those in the yeast complexes, human SWI/SNF-B contains only the homolog that functions like Rsc during cell growth. Immunofluorescence studies with a BAF180 antibody revealed that SWI/SNF-B localizes at the kinetochores of chromosomes during mitosis. Our data suggest that SWI/SNF-B and Rsc represent a novel subfamily of chromatin-remodeling complexes conserved from yeast to human, and could participate in cell division at kinetochores of mitotic chromosomes.

Adenosine Triphosphatases↗
PubMed2000

The murine Otp homeobox gene plays an essential role in the specification of neuronal cell lineages in the developing hypothalamus.

Hypothalamic nuclei, including the anterior periventricular (aPV), paraventricular (PVN), and supraoptic (SON) nuclei strongly express the homeobox gene Orthopedia (Otp) during embryogenesis. Targeted inactivation of Otp in the mouse results in the loss of these nuclei in the homozygous null neonates. The Otp null hypothalamus fails to secrete neuropeptides somatostatin, arginine vasopressin, oxytocin, corticotropin-releasing hormone, and thyrotropin-releasing hormone in an appropriate spatial and temporal fashion, and leads to the death of Otp null pups shortly after birth. Failure to produce these neuropeptide hormones is evident prior to E15.5, indicating a failure in terminal differentiation of the aPV/PVN/SON neurons. Absence of elevated apoptotic activity, but reduced cell proliferation together with the ectopic activation of Six3 expression in the presumptive PVN, indicates a critical role for Otp in terminal differentiation and maturation of these neuroendocrine cell lineages. Otp employs distinct regulatory mechanisms to modulate the expression of specific molecular markers in the developing hypothalamus. At early embryonic stages, expression of Sim2 is immediately downregulated as a result of the absence of Otp, indicating a potential role for Otp as an upstream regulator of Sim2. In contrast, the regulation of Brn4 which is also expressed in the SON and PVN is independent of Otp function. Hence no strong evidence links Otp and Brn4 in the same regulatory pathway. The involvement of Otp and Sim1 in specifying specific hypothalamic neurosecretory cell lineages is shown to operate via distinct signaling pathways that partially overlap with Brn2.

Animals↗
PubMed2000

Expression and structural characterization of the recombinant human doppel protein.

The doppel protein (Dpl) is a newly recognized prion protein (PrP)-like molecule encoded by a novel gene locus, prnd, located on the same chromosome as the PrP gene. To study the structural features of Dpl, we have expressed recombinant human Dpl corresponding to the putative mature protein domain (residues 24-152) in Escherichia coli. The primary structure of the recombinant Dpl 24-152 was characterized using gel electrophoresis, N-terminal Edman sequencing, matrix-assisted laser desorption ionization mass spectrometry, and electrospray ionization mass spectrometry. Dpl 24-152 was shown to contain two disulfide bonds (Cys94-Cys145 and Cys108-Cys140). The secondary structure of Dpl was analyzed using far-UV circular dichroism spectroscopy. Dpl 24-152 was found to be an alpha-helical protein having a high helical content (40%). Dpl 24-152 exhibited characteristics of a thermodynamically stable protein that undergoes reversible and cooperative thermal denaturation. In addition, Dpl was found to be soluble and sensitive to proteinase K digestion. Therefore, Dpl 24-152 possesses biochemical properties similar to those of recombinant PrP. This study provides knowledge about the molecular features of human Dpl that will be useful in further investigation into its normal function and the role it may play in neurodegenerative diseases.

Amino Acid Sequence↗