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Biomedical subjects

W Gong

Publications and source records attributed to W Gong.

At least 91 records · Page 5Linked to original sources
PubMed1996

Purification, crystallization and preliminary X-ray diffraction analysis of haemorrhagin IV from the snake venom of Agkistrodon acutus.

Haemorrhagin IV, a medium molecular weight haemorrhagin from the snake venom of Agkistrodon acutus (AaHIV), has been purified and crystallized. The molecular weight and isoelectric point of AaHIV are 44 kDa and pI 5.0, respectively. The crystal belongs to space group C222(1) with unit-cell dimensions of a = 124.2, b = 114.5, c = 98.4 A, and could o diffract X-rays to 3.0 A, resolution. There are one or two molecules in the crystallographic asymmetric unit.

Journal Article↗
PubMed1996

Conditioned place preference and locomotor activation produced by injection of psychostimulants into ventral pallidum.

The ventral pallidum (VP) is often viewed as an output structure of the nucleus accumbens septi (NAS). However, VP, like NAS, receives a dopaminergic input from the ventral tegmental area. These experiments investigated some behavioral effects of microinjection into VP of drugs which enhance dopaminergic transmission. Injection of 25 micrograms dopamine or 5-10 micrograms amphetamine into VP produced hypermotility. In contrast, injection of 12.5-50 micrograms cocaine initially suppressed, then increased, activity. Injection of 100 micrograms cocaine only produced hypomotility in the 1-h period examined. The hypomotility following cocaine seemed to be a local anesthetic effect, because it was mimicked by 50-200 micrograms procaine. Procaine did not, however, produce subsequent hypermotility. Conditioned place preference (CPP) was produced by 10 micrograms amphetamine and 50 micrograms cocaine but not 100 micrograms procaine. We conclude that injection of cocaine into VP unlike similar injections into NAS, produces CPP. These results support the idea of an involvement of dopamine in VP in reward and locomotor activation, independent of dopamine in NAS. The use of intracerebral injections of cocaine is complicated, however, by an apparent local anesthetic effect of the drug.

Amphetamine↗
PubMed1996

Crystallization and preliminary X-ray diffraction studies of haemorrhagin I from the snake venom of Agkistrodon acutus.

Haemorrhagin I from the snake venom of Agkistrodon acutus (AaHI) has been crystallized using the hanging-drop vapour diffusion method. The crystals belong to space group P4(1)2(1)2 or P4(3)2(1)2 with unit-cell dimensions a = b = 63.61 and c = 95.69 A. There is one molecule in the asymmetric unit. Data to 2.35 A resolution have been collected using a single-crystal.

Journal Article↗
PubMed1996

Human recombinant monocyte chemotactic protein and other C-C chemokines bind and induce directional migration of dendritic cells in vitro.

Because dendritic cells (DC) are the most potent antigen-presenting cells involved in many pathophysiological responses, we investigated the effect of chemokines on the migration of these cells in an effort to determine whether chemokines may contribute to the initiation of immune responses. CD34+ progenitor cells isolated from umbilical cord blood were grown in suspension cultures with cytokines and expanded 50- to 100-fold. A variable proportion of the cells expressed markers consistent with DC. The proportion of CD1a+ DC was increased when the cells were cultured with interleukin-4 (IL-4). These cells expressed specific binding sites for C-C and C-X-C chemokines. Cells cultured with or without IL-4 had similar binding profiles. All C-C chemokines tested, including monocyte chemotactic protein (MCP)-1, MCP-2, MCP-3, macrophage inflammatory protein-1 alpha (MIP1 alpha), MIP-1 beta, and RANTES, induced migration of DC-enriched cells cultured with or without IL-4 with MCP-3 being the most potent chemoattractant. Phenotypic analysis of cell migrating in response to C-C chemokines showed that CD1a+ cells were indeed attracted across the polycarbonate filters, and there was no preferential attraction of contaminating CD14+ monocytes by C-C chemokines. DC-enriched cells also expressed specific binding sites for IL-8 and NAP2, which failed to induce cell migration. Our results suggest that C-C chemokines may participate in the recruitment of DC to amplify host defense.

Binding Sites↗
PubMed1996

A transcription map of the DiGeorge and velo-cardio-facial syndrome minimal critical region on 22q11.

The majority of patients with DiGeorge syndrome (DGS) and velo-cardio-facial syndrome (VCFS) have a microdeletion of 22q11. Using translocation breakpoints and fluorescence in situ hybridization analysis (FISH), the minimal DiGeorge critical region (MDGCR) has been narrowed to 250 kb in the vicinity of D22S75 (N25). The construction of a detailed transcription map covering the MDGCR is an essential first step toward the identification of genes important to the etiology of DGS/VCFS, two complex disorders. We have identified a minimum of 11 transcription units encoded in the MDGCR using a combination of methods including cDNA selection, RT-PCR, RACE and genomic sequencing. This approach is somewhat unique and may serve as a model for gene identification. Of the 11 transcripts, one is the previously reported DGCR2/IDD/LAN gene, and three revealed a high level of similarity to mammalian genes: a Mus musculus serine/threonine kinase, a rat tricarboxylate transport protein and a bovine clathrin heavy chain. The remaining transcripts do not demonstrate any significant homology to genes of known function. The identification of these transcription units in the MDGCR will facilitate their further characterization and help elucidate their role in the etiology of DGS/VCFS.

Abnormalities, Multiple↗
PubMed1996

The fragmentation of 510 MeV/nucleon iron-56 in polyethylene. I. Fragment fluence spectra.

The fragmentation of 510 MeV/nucleon iron ions in several thicknesses of polyethylene has been measured. Non-interacting primary beam particles and fragments have been identified and their LETs calculated by measuring ionization energy loss in a stack of silicon detectors. Fluences, normalized to the incident beam intensity and corrected for detector effects, are presented for each fragment charge and target. Histograms of fluence as a function of LET are also presented. Some implications of these data for measurements of the biological effects of heavy ions are discussed.

Algorithms↗
PubMed1996

Locomotor response to novelty does not predict cocaine place preference conditioning in rats.

Previous studies have demonstrated that rats showing a strong locomotor response to a novel environment have a greater locomotor response to psychostimulant drugs and more rapidly acquire intravenous self-administration of amphetamine. In this report, we examined whether these high-responder (HR) rats would develop place-preference conditioning with cocaine more readily than low-responder (LR) rats. Neither group of rats developed conditioned place preference for cocaine, 2.5 mg/kg, intraperitoneally (IP). Both groups of rats developed conditioned place preference for cocaine, 5.0 and 15 mg/kg, IP. However, we could not find any evidence of enhanced conditioning in the HR rats. HR rats did show a greater locomotor response to cocaine, 15 mg/kg, IP, and the locomotor response of HR and LR rats to cocaine correlated with their response to a novel environment. We conclude that using the place-preference procedure, HR and LR rats do not differ in the rewarding effect of cocaine.

Animals↗
PubMed1996

Locomotor response to novelty does not predict cocaine place preference conditioning in rats.

Previous studies have demonstrated that rats showing a strong locomotor response to a novel environment have a greater locomotor response to psycho-stimulant drugs and more rapidly acquire intravenous self-administration of amphetamine. In this report, we examined whether these high-responder (HR) rats would develop place-preference conditioning with cocaine more readily than low-responder (LR) rats. Neither group of rats developed conditioned place preference for cocaine, 2.5 mg/kg, intraperitoneally (IP). Both groups of rats developed conditioned place preference for cocaine, 5.0 and 15 mg/kg, IP. However, we could not find any evidence of enhanced conditioning in the HR rats. HR rats did show a greater locomotor response to cocaine, 15 mg/kg, IP, and the locomotor response of HR and LR rats to cocaine correlated with their response to a novel environment. We conclude that using the place-preference procedure, HR and LR rats do not differ in the rewarding effect of cocaine.

Animals↗
PubMed1996

[A clinical study of multistage isoproterenol tilt table test for patients with unexplained syncope].

The purpose of the present study is to evaluate the clinical usefulness of multistage isoproterenol tilt table test (MITTT) in patients with syncope of unexplained origin. 35 patients (mean age 40 +/- 8 years) with syncope of unknown origin and 20 patients (mean age 49 +/- 7 years) with sinus bradycardia as controls were subjected to successive MITTT (4 stage). 28 of the 35 patients with syncope of unknown origin who underwent the MITTT developed syncope (80% positive response). Only 2 of the 20 patients with sinus bradycardia developed syncope (10% positive response). There was a highly significant statistical difference in positive response between the two groups (P < 0.001). If MITTT was combined with isoproterenol test (< or = 3 micrograms/min), positive response was obtained in 95% and only 5 minutes were sufficient to induce positive response. The mean heart rate-pressure product accurately indentified both positive and negative test results (positive predictive value < or = 1.2 x 10(3) kPa/min, negative predictive value > 1.3 x 10(3) kPa/min). These results suggest that MITTT is a valuable provocative test for vasovagal syncope.

Adolescent↗
PubMed1995

Increased sensitivity to cocaine place-preference conditioning by septal lesions in rats.

Rats bearing electrolytic lesions of medial septum and sham-operated controls were trained on cocaine place-preference in a 3-compartment apparatus. Cocaine was paired with a white or a black compartment. An unbiased design was used, in which cocaine was paired with the preferred side in half the animals and with the unpreferred side in the other half. Two low doses of cocaine HCl were used: 2.5 and 5.0 mg/kg. Only two pairings of drug with environment were used to minimize the influence of drug sensitization. Rats with septal lesions, but not controls, showed preference conditioning to the black side at 2.5 mg/kg; lesioned and control animals showed similar conditioning to the black side at 5.0 mg/kg. Lesioned animals could not be conditioned to the white side at either dose. This was attributed to a drug-induced enhancement of a previously described increased reactivity to brightness following septal lesions. Controls conditioned to either side at 5.0 mg/kg. It was concluded that septal lesions lowered the cocaine dose required for preference conditioning, consistent with reports that such damage enhances some behavioral effects of psychostimulants.

Animals↗
PubMed1995

Cloning a balanced translocation associated with DiGeorge syndrome and identification of a disrupted candidate gene.

DiGeorge syndrome (DGS), a developmental defect, is characterized by cardiac defects and aplasia or hypoplasia of the thymus and parathyroid glands. DGS has been associated with visible chromosomal abnormalities and microdeletions of 22q11, but only one balanced translocation--ADU/VDU t(2;22)(q14;q11.21). We now report the cloning of this translocation, the identification of a gene disrupted by the rearrangement and the analysis of other transcripts in its vicinity. Transcripts were identified by direct screening of cDNA libraries, exon amplification, cDNA selection and genomic sequence analysis using GRAIL. Disruption of a gene in 22q11.2 by the breakpoint and haploinsufficiency of this locus in deleted DGS patients make it a strong candidate for the major features associated with this disorder.

Amino Acid Sequence↗
PubMed1994

A modular solid state detector for measuring high energy heavy ion fragmentation near the beam axis.

A multi-element solid state detector has been designed to measure fluences of fragments produced near the beam axis by high energy heavy ion beams in thick targets. The detector is compact and modular, so as to be readily reconfigured according to the range of fragment charges and energies to be measured. Preamplifier gain settings and detector calibrations are adjustable remotely under computer control. We describe the central detector, its associated detectors and electronics, triggering scheme, data acquisition and particle identification techniques, illustrated by data taken with 600 MeV/u 56Fe beams and thick polyethylene targets at the LBL Bevalac. The applications of this work to space radiation protection are discussed.

Algorithms↗
PubMed1994

A YAC clone map spanning 7.5 megabases of human chromosome band Xq28.

Xq28 has been of special interest in human genetics because a large number of diseases map to this region. As a step in the molecular analysis of the as yet uncloned disease genes, and as a test for the detailed analysis of larger regions of the genome, we have constructed YAC clone contigs covering the 7.5 Mb region between IDS to the telomere on the long arm of the human X chromosome. Contigs were assembled and verified by an integrated hybridization-based strategy. Data was combined from the physical map, from YAC and cosmid mapping experiments, and from the localization of specific transcripts in the region. Two gaps in the YAC map of 250 and 100 kb were covered in part by the aid of cosmid clones, but small gaps of 50 kb each remain. The cloned region is expected to contain yet unidentified genes for at least ten genetic diseases. The construction of ordered YAC clone contigs of Xq28 represents an important step in the molecular identification of these genes, and the further analysis of one of the genetically most interesting regions of the human genome.

Chromosomes, Artificial, Yeast↗
PubMed1994

X linked myotubular myopathy (MTM1) maps between DXS304 and DXS305, closely linked to the DXS455 VNTR and a new, highly informative microsatellite marker (DXS1684).

The locus for X linked recessive myotubular myopathy (MTM1) has previously been mapped to Xq28 by linkage analysis. We report two new families that show recombination between MTM1 and either DXS304 or DXS52. These families and a third previously described recombinant family were analysed with two highly polymorphic markers in the DXS304-DXS52 interval, the DXS455 VNTR and a newly characterised microsatellite, DXS1684 (82% heterozygosity). These markers did not recombine with MTM1 in the three families. Together with the recent mapping of an interstitial X chromosome deletion in a female patient with moderate signs of myotubular myopathy, our data suggest the following order of loci in Xq28: cen-DXS304-(DXS455, MTM1)-DXS1684-DXS305-DXS52-tel. This considerably refined localisation of the MTM1 locus should facilitate positional cloning of the gene. The availability of highly polymorphic and very closely linked markers will markedly improve carrier and prenatal diagnosis of MTM1.

Base Sequence↗
PubMed1994

A new functional classification of stomach cancer and its pathobiological and clinical significance.

The functional differentiations of stomach cancer specimens from 121 patients were investigated by enzyme-, mucin-, affinity- and immunohistochemical methods, and the stomach cancers were divided into five functionally differentiated types: 1) Absorptive Function Differentiation Type (AFDT), 19.8%; 2) Mucin Secreting Function Differentiation Type (MSFDT), 24.0%; 3) Absorptive and Mucin-Producing Function Differentiation Type (AMPFDT), 47.1%; 4) Special Function Differentiation Type (SFDT), 0.8%; and 5) Non-Function Differentiation Type (NFDT), 8.3%. The results indicate that stomach cancer tissues of the same histological type often display differing functional differentiation, and these functionally differentiated types have different invasive and metastatic characteristics. In addition, the functionally differentiated types have particular organic affinities of metastasis and different clinical prognoses. This study suggests that this new functional classification may supplement histological classification. The mechanisms of liver and ovary metastases of stomach cancer are also discussed.

Adenocarcinoma↗
PubMed1993

[Determination of apparent pharmacokinetic parameters of shengfu injection by acute mortality of mice].

Apparent pharmacokinetic parameters of Shengfu injection, a first-aid traditional Chinese medicine, were determined by acute mortality of animals. The results suggested that the pharmacokinetics of Shengfu injection accords with the two compartment open model, and t1/2 alpha = 0.063h, t1/2 beta = 2.70h. The process of distribution was quite rapid, and the process of elimination was slow.

Animals↗
PubMed1993

[Study on dissolution rate and bioavailability of norfloxacin capsule by UV-spectrophotometry].

The dissolution rates and bioavailability of norfloxacin in seven batches of norfloxacin capsules produced by five pharmaceutical factories were studied with rotating basket and UV-spectrophotometry. The results showed that the T50, Td and m of the samples had obvious differences, and the correlation between the dissolution rate and bioavailability differed very obviously. The method used is simple and convenient. So UV-spectrophotometry is one of the methods for the assay of norfloxacin preparations in vitro and in vivo.

Biological Availability↗