Search PubMed⌕ Search

Biomedical subjects

M Wang

Publications and source records attributed to M Wang.

At least 397 records · Page 22Linked to original sources
PubMed1999

Early IL-4 production driving Th2 differentiation in a human in vivo allergic model is mast cell derived.

IL-4 is central to the formation of IgE and the development of Th2 effector cells, both key features of an allergic response. We have examined IL-4 production early in the formation of an allergic response by using a previously established human in vivo model of allergic rhinitis where allergic subjects are challenged internasally with allergen and the particulate pollutant diesel exhaust particles (DEP). This model is characterized by enhanced IgE production and deviation to a Th2-type cytokine profile in nasal lavage fluid from these subjects. In this model, IL-4 protein and IL-4-positive cells could first be detected 4 h after challenge and maximal production was observed after 18 h. Two-color flow cytometric analysis for the detection of intracellular IL-4 and surface markers was performed on nasal cells recovered 4 h after challenge. At this time, CD117(+) (c-kit+) cells constituted between 65 and 100% of the IL-4(+) cells, while 0-12% of the IL-4(+) cells were CD3 positive. No IL-4(+) CD19/CD20(+) or IL-4(+) CD56(+) cells were detected at 4 h. As the allergic response progressed the primary source of IL-4 changed. At the peak of IL-4 production, 18 h after challenge, CD3(+) comprised the majority of cells staining for intracellular IL-4 (73 to 100%). Thus we show an initial role for cells of the mast cell/basophil lineage residing in the nasal mucosa in the initial production of IL-4, which frames the subsequent immune response by expanding the repertoire of TH2 cytokine-producing cells in the local microvicinity.

Adult↗
PubMed1999

An advanced generation of adenoviral vectors selectively enhances gene transfer for ovarian cancer gene therapy approaches.

OBJECTIVE: We hypothesized that incorporation of an integrin binding Arg-Gly-Asp (RGD)-containing peptide to the HI loop of the adenovirus fiber knob would allow enhanced, coxsackie-adenovirus receptor-independent gene transfer by modified Ad vector in the context of ovarian cancer. METHODS: Ovarian cancer cell lines, primary ovarian cancer cells, primary tumor explants, and mesothelial tissue were transfected with luciferase encoding adenovirus (AdCMVLuc) or a genetically modified adenovirus (Ad5lucRGD) which contained an RGD motif within the HI loop of the knob. The luciferase activity was measured and the transduction efficiencies of both viruses were compared. RESULTS: In all established ovarian cell lines and primary tumor cell samples there was dramatically augmented gene transfer observed with the Ad5lucRGD compared to AdCMVLuc. The enhanced gene transfer in ovarian cancer cell lines ranged from 2.5- to 471.6-fold, in ascites samples from 26.1- to 64.0-fold, and in tumor explants from 1.6- to 11.1-fold. Although gene transfer to normal mesothelial tissue was slightly augmented by RGD retargeting, the level of gene transfer was much lower than that seen in ovarian cancer cells. CONCLUSION: This study demonstrates that genetically altered adenoviruses with modified tropism are capable of more efficient gene transfer in the context of ovarian cancer. The higher level of transfer with respect to peritoneal mesothelium can be exploited to enhance the therapeutic index of interventions using adenoviral vectors. Studies are warranted, therefore, to determine the in vivo utility of this targeted vector approach in the context of gene therapeutic strategies for cancer of the ovary.

Adenoviridae↗
PubMed1999

Growth-promoting effect of recombinant human growth hormone and stanozolol in girls with Turner syndrome.

Ten girls with Turner syndrome were treated with a combination therapy of recombinant human growth hormone (R-hGH) and low dose stanozolol for a period of 8 to 36 months. The results showed that when compared with the growth rate before the treatment, the growth rates after treatment with R-hGH and stanozolol showed a sustained increase, reaching 9.0 +/- 1.9 cm/year during the first year of treatment; the height age increase by 2.5 +/- 0.8 years while the bone age increase were 1.0 +/- 0.7 years; and the predicted final adult height at the end of the first year of the treatment increased to 149.4 +/- 6.1 cm compared to their original mean of 142.8 +/- 4.2 cm. We are led to conclude that therapy with R-hGH in combination with stanozolol can increase the growth velocity and significantly increase the predicted adult height of children with Turner syndrome.

Adolescent↗
PubMed1999

The Role of Abscisic Acid in Induction of Androgenesis: A Comparative Study Between Hordeum vulgare L. Cvs. Igri and Digger.

Under the same mannitol pretreatment and culture conditions, regeneration efficiency in the barley cultivar (cv.) Igri was about 10 times higher than in the cv. Digger, a difference only partially reflected by a difference in viable microspores after anther pretreatment. Therefore, a comparative study between cvs. Igri and Digger was carried out under various pretreatment conditions. For both cultivars, under water, CPW buffer and mannitol pretreatment conditions, there was a positive correlation between microspore viability and regeneration efficiency in that mannitol > CPW buffer >> water. Mannitol pretreatment of cv. Igri produced a much higher endogenous abscisic acid (ABA) level than as to Digger. Addition of ABA stimulated both percentages of viability and regeneration efficiency except in the case of mannitol pretreatment. Under CPW buffer pretreatment conditions, addition of ABA significantly stimulated regeneration efficiency and was ABA concentration dependent. However, cv. Digger was less responsive to ABA than cv. Igri. In both cultivars, under less optimal pretreatment conditions (e.g., water and CPW buffer), the effect of ABA was to stimulate increased percentages of viability and/or to reduce the number of binucleate microspores. Moreover, in cv. Igri, direct culture of anthers for 4 days without pretreatment caused an increased number of binucleate microspores compared with microspores with pretreatment for 4 days. These binucleate microspores showed DNA degradation in the nuclei. However, with mannitol pretreatment binucleate microspores and DNA fragmentation in the nuclei of microspores was rarely observed. On the basis of our observations, we suggest that the difference in regeneration efficiency in cv. Igri and cv. Digger is related to the differences in endogenous ABA production levels under mannitol pretreatment and responsiveness to ABA. One of the effects of ABA is likely due to an inhibition of cell death.

Journal Article↗
PubMed1999

JC virus genotypes in a Taiwan aboriginal tribe (Bunun): implications for its population history.

The origin of Taiwanese aborigines remains obscure; it has been speculated that they may be from either mainland China or southeastern Asia. We used the JCV genotyping method to elucidate the origin of Bunun aborigines who now live in central mountain areas of Taiwan. We found that Bunun aborigines carried two major (B1-a2 and CY) and two minor JCV genotypes (B1-a1 and SC). This was contrasted with the JCV genotype profile in modern Taiwanese: one major (SC) and two minor genotypes (CY and B1-a1). It thus appears that B1-a2 and CY are indigenous to the Bunun tribe. B1-a2 was first identified in this study as a discrete cluster that contained only Bunun and Philippine JCV isolates and that was closely related to B1-a1, one of the three common JCV genotypes in China. CY predominates in North China, while SC predominates in South China and southeastern Asia. The present findings suggest that the Bunun tribe is an admixture of two ethnic groups, one carrying B1-a2 and the other carrying CY. In other words, it is likely that the Bunun tribe was established by two waves of immigrations from mainland Asia, predating those by southern Chinese which began in the 17th century.

Adolescent↗
PubMed1999

Two C21-steroidal glycosides isolated from Cynanchum stauntoi.

Studies on the roots of Cynanchum stauntoi led to the isolation of two C21-steroidal glycosides, formally named stauntosides A and B. Their structures were elucidated on the basis of spectroscopic evidence, especially that from analysis of 2D-NMR spectra. They were found to possess an unusual skeleton and were identified as stauntogenin 3-O-alpha-L-diginopyranosyl-(1-4)-beta-L-cymaropyranosyl-(1- 4)-beta-D- digitoxopyranosyl-(1-4)-beta-D-thevetopyranoside and stauntogenin 3-O-alpha-L-cymaropyranosyl-(1-4)-beta-D-digitoxopyranosyl-( 1-4)-beta-D-3- demethyl-2-deoxy-thevetopyranoside.

Carbohydrate Conformation↗
PubMed1999

Analysis of the steroid binding domain of rat steroid 5alpha-reductase (isozyme-1): the steroid D-ring binding domain of 5alpha-reductase.

We have previously shown that the photoactive 4-azasteroid, [1,2 3H]N-4(benzylbenzoyl)-3-oxo-4-aza-4-methyl-5alpha-androst an-17beta-carboxamide is an effective probe of rat steroid 5alpha-reductase (isozyme-1) (5alphaR-1). In the current investigation, PEG-fractionated (6.5%) detergent-solubilized preparations containing 5alphaR-1 activity were ultraviolet (UV)-photolyzed with [3H]-4MABP and subsequently purified by 8.75% preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The fractions corresponding to the radioactive peak following the dye front were analyzed by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis and showed the presence of a single, labeled, 26 KDa protein band, the apparent molecular weight of 5alphaR-1. TCA precipitation of the labeled fractions, followed by long-term digestion of the TCA pellet with chymotrypsin and high-performance liquid chromatography analysis, indicated that the majority of the radioactivity eluted with a peak retention time of 55-56 min. Rechromatography of this fraction using a modified gradient (elution 54-55 min), followed by sequence analysis, yielded a single N-terminal tetrapeptide with the sequence, -L-E-G-F-, corresponding to residues 15-18 of the 5alphaR-1 sequence. Site-directed mutagenesis studies indicated that mutant F18L showed an approximately 12-fold increase in the Km for testosterone, whereas the Km for reduced nicotinomide adenine dinucleotide phosphate remained virtually unaltered.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1999

Site-directed mutagenesis studies of the NADPH-binding domain of rat steroid 5alpha-reductase (isozyme-1) I: analysis of aromatic and hydroxylated amino acid residues.

Previous studies have shown that the reduced nicotinamide adenine dinucleotide phosphate (NADPH)- binding domain of rat liver microsomal steroid 5alpha-reductase isozyme-1 (r5alphaR-1) is in a highly conserved region of the polypeptide sequence (residues 160-190). In this study, we investigated, by site-directed mutagenesis, the role of hydroxylated and aromatic amino acids within the NADPH-binding domain. The r5alphaR-1 cDNA was cloned into a pCMV vector, and the double strand site-directed mutagenesis method was used to create mutants Y179F, Y179S, Y189F, Y189S, S164A, S164T, and Y187F, which were subsequently expressed in COS-1 cells. Kinetic studies of the expressed enzymes showed that the mutation Y179F resulted in an approximately 40-fold increase in the Km for NADPH versus wild-type, with only a 2-fold increase in the Km for testosterone. The mutants Y189F and S164A showed smaller increases (4 and 6-fold) in Kms for NADPH and no significant change in the Km for testosterone, whereas Y189S had kinetic properties similar to the wild-type r5alphaR-1. Mutants Y179S and S164T both resulted in inactive enzymes, whereas F187Y showed an approximately 5-fold decrease in Km for NADPH and a significant increase (approximately 18-fold) in the Km for testosterone. The results suggest that the -OH functionality of Y179 is involved in cofactor binding, but is not essential for the activity of the enzyme, whereas the -OH functionalities of Y189 and S164 play lesser roles in cofactor binding to r5alphaR-1 and may not be required for enzyme activity. On the other hand, the residue F187 may be important for the binding of both NADPH and testosterone.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1999

Molecular characterization of a new excitatory insect neurotoxin with an analgesic effect on mice from the scorpion Buthus martensi Karsch.

Besides the neurotoxins active on mammals, a new excitatory insect selective toxin with a mice analgesic activity was found and purified from the venom of the scorpion Buthus martensi Karsch (BmK) (Ji, Y.H., Mansuelle, P., Terakawa, S., Kopeyan, C., Yanaihara, N., Hsu, K., Rochat, H., 1996. Toxicon 34, 987; Luo, M.J., Xiong, Y.M., Wang, M., Wang, D.C., Chi, C.W., 1997. Toxicon 35, 723.). This peptide (designated as BmK IT-AP) is composed of 72 amino acid residues. Its primary structure was determined by automated Edman degradation of the N-terminal part of the reduced and S-carboxamidemethylated protein and its lysylendopeptidase degraded fragments. Based on the determined sequence, the gene specific primers were designed and synthesized for 3' and 5' RACE (rapid amplification of cDNA ends). Their partial cDNA fragments obtained by 3' and 5' RACEwere cloned and sequenced and the full length cDNA sequence of BmK IT-AP was then completed by overlapping their two partial cDNA sequences. It encodes a precursor of 90 amino acid residues: a signal peptide of 18 residues and a mature peptide of 72 residues which are consistent with the determined protein sequence of BmK IT-AP. The genomic DNA of the peptide was also amplified by PCR from the scorpion genomic DNA and sequenced, which is a first report on the genomic structure of a scorpion toxin specific for insects. Its sequence revealed an intron of 590 bp inserted in the end part of the signal peptide. The peptide caused a fast excitatory contraction paralysis on house fly larvae. Furthermore, the peptide also showed an obvious analgesic effect on mice, as assayed by using a twisting test model. This effect of BmK IT-AP well characterized at molecular level is first reported among the known scorpion insect neurotoxins.

Amino Acid Sequence↗
PubMed1999

Nasal challenge with diesel exhaust particles can induce sensitization to a neoallergen in the human mucosa.

BACKGROUND: Diesel exhaust particles (DEPs) increase in vivo IgE and cytokine production at the human upper respiratory mucosa, exacerbating allergic inflammation. OBJECTIVE: We examined the ability of DEP exposure to lead to primary sensitization of humans by driving a de novo mucosal IgE response to a neoantigen, keyhole limpet hemocyanin (KLH). METHODS: Ten atopic subjects were given an initial nasal immunization with 1 mg of KLH followed by 2 biweekly nasal challenges with 100 microg of KLH. Identical nasal KLH immunization was then performed on 15 different atopic subjects, but DEPs were administered 24 hours before each KLH exposure. RESULTS: Exposure to KLH alone led to the generation of an anti-KLH IgG and IgA humoral response, which was detected in nasal fluid samples. No anti-KLH IgE appeared in any subjects. In contrast, when challenged with KLH preceded by DEPs, 9 of the 15 subjects produced anti-KLH-specific IgE. KLH-specific IgG and IgA at levels similar to that seen with KLH alone could also be detected. Subjects who received DEPs and KLH had significantly increased IL-4, but not IFN-gamma, levels in nasal lavage fluid, whereas these levels were unchanged in subjects receiving KLH alone. CONCLUSION: These studies demonstrate that DEPs can act as mucosal adjuvants to a de novo IgE response and may increase allergic sensitization.

Adjuvants, Immunologic↗
PubMed1999

Human anti-JC virus serum reacts with native but not denatured JC virus major capsid protein VP1.

The immunoreactivity of human anti-JC virus (JCV) serum against the major capsid protein VP1 of JCV was analyzed by Western blot, dot blot, and hemagglutination inhibition (HAI) assays. JCV-positive human serum reacted with native but not denatured JCV major capsid protein VP1, as demonstrated by dot blot and Western blot. Rabbit antiserum raised against native JCV capsid had immunoreactivities similar to those of human anti-JCV serum. These results indicate that the antigenecity of native and denatured JCV VP1 is different. In addition, both JCV-positive human serum and rabbit antiserum raised against native JCV capsid protein inhibited the hemagglutination activity of JCV capsid particles. In contrast, rabbit antiserum raised against denatured JCV VP1 did not inhibit hemagglutination. These findings reveal that denaturation may alter the antigenic epitopes of JCV VP1. Therefore, keeping the JCV capsid protein native appears to be essential for serological or other immunological analyses of the virus.

Animals↗
PubMed1999

Influence of additives on the protoplasts electrofusion.

Various neutral or charged surface active substances were used for testing the influence of additives on the electrofusion of barley protoplasts. It was found that neutral surface active agents DX, TAGB, Span-80 and AEO-9 could promote the electrofusion. The positively charged surface active agents Bardac 2080, Bardac 2280 and amphoteric surface active agents dodecyl-propyl betaine and CAB betaine also promote the electrofusion, but at high concentration the electrofusion efficiency will reduce. The negatively charged polymer agents Cibacron blue DX, Fluoresceinylthiocarbamoyl DX, and active surface substances K12 and Carsonol TLS- presented negative effect. These phenomena were discussed from the view of adsorption of additives on the membrane and the interactions between protoplasts.

Cell Fusion↗
PubMed1999

Protective effects of the flavonoid mixture, silymarin, on fetal rat brain and liver.

We investigated the possibility that the flavonoid mixture, silymarin (SY), administered as the compound Silymarin Phytosome (PHYTO), could protect the fetus from maternally ingested EtOH. Seventy-six female rats were randomly assigned to one of seven groups: pair-fed control; chow fed control; EtOH; and four groups receiving EtOH and PHYTO in varying dosages. All groups except the chow-fed control were maintained on a liquid diet. On day 1 of pregnancy the dams began the treatment protocol. On day 21 of pregnancy the rats were sacrificed and the fetuses removed. Gamma glutamyl transpeptidase (GGTP) activity was determined for liver and brain tissue from both the fetuses and the dams. GGTP activity in the EtOH/silymarin treatment groups did not differ significantly from that observed for the pair-fed control group. The observed GGTP activity levels for the EtOH-only group were significantly higher than those attained by the pair-fed control group. Although GGTP activity did not vary significantly with the quantity of PHYTO administered, as PHYTO dose was increased, GGTP activity decreased.

Animals↗
PubMed1999

Alpha-2 adrenergic modulation of prefrontal cortical neuronal activity related to spatial working memory in monkeys.

The effects of systemically administered or iontophoretically applied clonidine (alpha-2 adrenergic agonist) and iontophoretically applied yohimbine (alpha-2 adrenergic antagonist) were examined on prefrontal cortical (PFC) neurons related to spatial working memory (SWM). Systemically administered clonidine (0.04 mg/kg) enhanced SWM-related PFC neuronal activity by 32.5 +/- 14.5%, (mean +/- SD; n = 25 neurons). The facilitatory effect of clonidine was antagonized by iontophoretically applied yohimbine. Iontophoretically applied clonidine enhanced SWM-related PFC neuronal activity by 38.2 +/- 18.6%, (n = 13 neurons), whereas similarly applied yohimbine suppressed it by 34.4 +/- 17.8% (n = 28 neurons). These results indicate that: a) systemically administered clonidine can facilitate SWM-related PFC neuronal activity through actions at alpha-2 adrenoceptors in the PFC; and b) conversely, blockade by yohimbine of alpha-2 adrenoceptors in the PFC suppresses SWM-related neuronal activity. The present study provides neurophysiological evidence that alpha-2 adrenoceptors in the PFC are involved in the cellular mechanisms underlying working memory.

Action Potentials↗