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R Wang

Publications and source records attributed to R Wang.

At least 361 records · Page 20Linked to original sources
PubMed1998

Effects of alprostadil and prazosin on motility, viability and membrane integrity of human sperm.

PURPOSE: We evaluated the effects of alprostadil, prazosin hydrochloride, and alprostadil/prazosin hydrochloride, agents used in the clinical treatment of male erectile dysfunction, on the motility, viability and membrane integrity of human sperm. MATERIALS AND METHODS: Ten healthy volunteers provided semen samples that were incubated with 0.4 mg./ml. alprostadil, 0.1 and 0.2 mg./ml. prazosin hydrochloride and 0.4 mg./ml. alprostadil plus 0.1 mg./ml. prazosin hydrochloride for 2 hours. Control incubations included polyethylene glycol 1450, the formulation vehicle for the clinical use of alprostadil and prazosin, and Ham's F-10 buffer. Serial evaluations of percent sperm motility, percent viability, membrane function (by hypo-osmotic swelling test) and several computer generated measurements of sperm motion, including straight line velocity, curvilinear velocity, linearity and amplitude of lateral head displacement, were made. RESULTS: None of the agents had a significant impact on the percentage of motile or viable sperm or on sperm membrane function. Incubation with 0.2 mg./ml. prazosin reduced straight line velocity and curvilinear velocity significantly compared with the other agents. These changes were most likely a direct result of the viscosity of the 0.2 mg./ml. prazosin solution and not a cellular or metabolic effect on the sperm. CONCLUSIONS: Alprostadil and prazosin hydrochloride at doses used in transurethral therapy for erectile dysfunction have no effect on the motility, viability and membrane integrity of human sperm.

Adrenergic alpha-Antagonists↗
PubMed1998

Trilinolein inhibits the adhesion of neutrophils to endothelial cells.

1. Trilinolein is a triacylglycerol with linoleic acid as the only type of fatty acid in all three esterified positions of glycerol. It was recently reported to have a myocardial protective effect in coronary ligated rats. We now study its effect on the adhesion of human neutrophils to cultured bovine endothelial cells. 2. Pretreatment of an endothelial monolayer with trilinolein at concentrations ranging from 10(-10) to 10(-6) mol/L significantly inhibited neutrophil adhesion to endothelial cells. Trilinolein was less potent than sodium nitroprusside in inhibiting neutrophil adhesion. 3. The inhibitory effect of trilinolein was antagonized by methylene blue and N(G)-nitro-L-arginine methyl ester. The inhibitory effect of trilinolein was not mediated through linoleic acid because linoleic acid did not inhibit neutrophil adhesion. 4. Pretreatment of neutrophils with trilinolein did not reduce neutrophil adhesion. However, in neutrophils activated with N-formyl-methionyl-leucyl-phenylalanine, trilinolein inhibited the neutrophil adhesion to endothelial cells. 5. We conclude that trilinolein inhibits neutrophil adhesion to the endothelial monolayer by stimulating the nitric oxide and cyclic GMP pathways in endothelial cells. It may also inhibit neutrophil adhesion by scavenging free radicals. The inhibitory effect of trilinolein on neutrophil adhesion may play a role in its myocardial protective activity.

Animals↗
PubMed1998

Monte Carlo dosimetry of the VariSource high dose rate 192Ir source.

The purpose of the work is to calculate basic dosimetry data for a VariSource high dose rate 192Ir source in water. These basic dosimetry data, expressed in the dose calculation formalism endorsed by the Interstitial Collaborative Working Group and AAPM Task group 43, include the dose rate constant, the radial dose function, and the anisotropy function. A modified version of the EGS4 Monte Carlo code was used to calculate (1) the transverse-axis dose distribution at radial distances from 0.1 to 14 cm, (2) the two-dimensional dose distribution for axial and radial distances from 0.1 cm to 10 cm, and (3) the air-kerma strength, for the VariSource high dose rate 192Ir source. From these Monte Carlo results the basic dosimetry data were derived. The calculated dose rate constant for the high dose rate source is 1.044 +/- 0.2% cGy h-1 per unit air-kerma strength. The anisotropy function exhibits 40%-60% deviations from isotropy at positions on the long axis. The radial dose function for the source is nearly identical to that for a microSelectron high dose rate 192Ir source, except at radial distances smaller than 0.5 cm where values for VariSource are 1.7%-2.8% smaller. These basic dosimetry data were compared with corresponding results from other authors for high and low dose rate 192Ir sources, as well as with Meisberger's fitting formula.

Brachytherapy↗
PubMed1998

Protection of mice against Plasmodium yoelii sporozoite challenge with P. yoelii merozoite surface protein 1 DNA vaccines.

Immunization of mice with DNA vaccines encoding the full-length form and C and N termini of Plasmodium yoelii merozoite surface protein 1 provided partial protection against sporozoite challenge and resulted in boosting of antibody titers after challenge. In C57BL/6 mice, two DNA vaccines provided protection comparable to that of recombinant protein consisting of the C terminus in Freund's adjuvant.

Animals↗
PubMed1998

Simultaneous induction of multiple antigen-specific cytotoxic T lymphocytes in nonhuman primates by immunization with a mixture of four Plasmodium falciparum DNA plasmids.

CD8(+) T cells have been implicated as critical effector cells in protective immunity against malaria parasites developing within hepatocytes. A vaccine that protects against malaria by inducing CD8(+) T cells will probably have to include multiple epitopes on the same protein or different proteins, because of parasite polymorphism and genetic restriction of T-cell responses. To determine if CD8(+) T-cell responses against multiple P. falciparum proteins can be induced in primates by immunization with plasmid DNA, rhesus monkeys were immunized intramuscularly with a mixture of DNA plasmids encoding four P. falciparum proteins or with individual plasmids. All six monkeys immunized with PfCSP DNA, seven of nine immunized with PfSSP2 DNA, and five of six immunized with PfExp-1 or PfLSA-1 DNA had detectable antigen-specific cytotoxic T lymphocytes (CTL) after in vitro restimulation of peripheral blood mononuclear cells. CTL activity was genetically restricted and dependent on CD8(+) T cells. By providing the first evidence for primates that immunization with a mixture of DNA plasmids induces CD8(+) T-cell responses against all the components of the mixture, these studies provide the foundation for multigene immunization of humans.

Amino Acid Sequence↗
PubMed1998

Resurgence of carbon monoxide: an endogenous gaseous vasorelaxing factor.

Carbon monoxide (CO) is an endogenously generated gas that may play an important physiological role in the regulation of vascular tone. The CO-induced vasorelaxation, as a result of a direct action on vascular smooth muscles, has been demonstrated in many cases. Three major cellular mechanisms are proposed to explain the vasorelaxing effect of CO. These include the activation of soluble guanylyl cyclase, stimulation of various types of K channels, and inhibition of the cytochrome P450 dependent monooxygenase system in vascular smooth muscle cells. An interaction between CO and nitric oxide may also significantly contribute to the fine tuning of vascular tone. Furthermore, alterations in either the endogenous production of CO or the vascular responsiveness to CO have been encountered in several pathophysiological situations. A better understanding of the vascular effects of CO and the underlying cellular and molecular mechanisms will pave the way for the establishment of the role played by CO in vascular physiology and pathophysiology.

Animals↗
PubMed1998

Integrin expression in developing smooth muscle cells.

We studied the specific expression patterns and distributions of alpha1 and beta1 integrin subunits, the major cell adhesion receptors in smooth muscle, in developing smooth muscle cells from 16-, 18-, and 20-day embryonic gizzards and from 1- and 7-day post hatch chick gizzards by SDS-PAGE, immunoblotting, and immunoelectron microscopy. Antibodies raised against alpha1 and beta1 integrins isolated from avian gizzards were used as probes. Gels and blots showed that the amount of alpha1 and beta1 integrins increased as age increased, with major increases at 1 and 7 days post hatch. Image analysis of immunoelectron micrographs demonstrated that statistically significant labeling increases occurred between embryonic Days 16 and 18, between embryonic Day 20 and 1 day post hatch, and between 1 day and 7 days post hatch. Immunolabeling with both anti-alpha1 and anti-beta1 integrin was prominent at membrane-associated dense plaques (MADPs) and at filament anchoring regions at cell ends. This indicates that alpha1 and beta1 integrin expression coincides temporally with the intracellular proliferation and reorientation of myofilaments. The similarity in distribution patterns of alpha1 and beta1 integrins during development suggests that the two integrin subunits are synchronously expressed during development and do not appear sequentially. (J Histochem Cytochem 46:119-125, 1998)

Animals↗
PubMed1998

Binding of injected laminin to developing kidney glomerular mesangial matrices and basement membranes in vivo.

During glomerular development, subendothelial and -epithelial basement membrane layers fuse to produce the glomerular basement membrane (GBM) shared by endothelial cells and epithelial podocytes. As glomeruli mature, additional basement membrane derived from podocytes is spliced into the fused GBM and loose mesangial matrices condense. The mechanisms for GBM fusion, splicing, and mesangial matrix condensation are not known but might involve intermolecular bond formation between matrix molecules. To test for laminin binding sites, we intravenously injected mouse laminin containing alpha1-, beta1-, and gamma1-chains into 2-day-old rats. Kidneys were immunolabeled for fluorescence and electron microscopy with domain-specific rat anti-mouse laminin monoclonal antibodies (MAbs), which recognized only mouse and not endogenous rat laminin. Intense labeling for injected laminin was found in mesangial matrices and weaker labeling was seen in GBMs of maturing glomeruli. These patterns persisted for at least 2 weeks after injection. In control newborns receiving sheep IgG, no binding of injected protein was observed and laminin did not bind adult rat glomeruli. To assess which molecular domains might mediate binding to immature glomeruli, three proteolytic laminin fragments were affinity-isolated by MAbs and injected into newborns. These failed to bind glomeruli, presumably owing to enzymatic digestion of binding domains. Alternatively, stable incorporation may require multivalent laminin binding. We conclude that laminin binding sites are transiently present in developing glomeruli and may be functionally important for GBM assembly and mesangial matrix condensation.

Animals↗
PubMed1998

Salsalate administration--a potential pharmacological model of the sick euthyroid syndrome.

This study examined salsalate ingestion as a model of the sequelae of acute inhibition of thyroid hormone binding to serum protein. One dose of salsalate (60-65 mg/kg) was administered to healthy volunteers. Serum salsalate concentrations peaked at 2 h (82 micrograms/mL), then declined at 8 h to 1.2 micrograms/mL. Serum total T4 (TT4) and total T3 (TT3) concentrations declined for 4 h, then recovered by 96 h, while T4 binding protein concentrations remained unchanged. TT3 was reduced to a greater extent than TT4 between 2 h and 72 h, and serum total reverse(r)T3 (TrT3) was transiently increased at 8 h. TSH concentrations fell while TT4 and TT3 fell, then recovered while TT4, TT3, and free T3, but not free T4, were still reduced. Subsequently, TSH overshot basal levels and continued to rise after 96 h while TT4, TT3, free T4, free T3, and TrT3 were all at basal levels. We postulate that an acute release of T4 and T3 from circulating transport proteins, induced by an inhibitor of binding, can result in large and rapid redistribution of T4 and T3 into tissue compartments associated with transiently reduced peripheral tissue 5'-monodeiodination and deranged TSH regulation.

Adult↗
PubMed1998

Effects of serum of streptozotocin-induced diabetic rats on vascular smooth muscle cell growth in vitro.

This study was undertaken to biochemically and immunohistochemically clarify the expression of basic fibroblast growth factor (bFGF), insulin-like growth factor-I (IGF-I), fibroblast growth factor receptor (bFGFR), insulin-like growth factor-I receptor (IGF-IR) and vascular smooth muscle cell (VSMC) growth by using Streptozotocin (STZ) treated rat serum. At 12, 16, 24 weeks after STZ administration, blood sera were collected from STZ treated rats. STZ treated rat sera promoted much more vascular smooth muscle cel proliferation than control sera. IGF-I was increased in the sera of STZ treated rats. Also according to western blot analysis, the protein synthesis of bFGFR and IGF-IR in the VSMCs was increased in STZ treated rat sera. Immunohistochemically, bFGF, IGF-I and their receptors were much more localized in VSMCs in STZ treated rat sera than in control sera. These results suggest that the growth factors and their receptors produced in VSMCs in STZ treated rat serum may contribute to the proliferation of VSMCs in autocrine and paracrine patterns.

Animals↗
PubMed1998

Human root dentin: structural anisotropy and Vickers microhardness isotropy.

The demanding mechanical functions and the variable structure of dentin make it an invaluable material for studying the structure-mechanical function relations of a mineralized collagen-containing tissue. The mineralized collagen fibril axes in human root dentin are mainly located on the incremental plane. Within this plane there is a preferred orientation in the general root-crown direction. The apatite crystals are aligned in three dimensions within an individual collagen fibril, but this orientation does not necessarily extend to the neighboring fibrils. Crystals are also present as aggregates without any preferred orientation. The structure is therefore clearly anisotropic with respect to the collagen fibril orientation, but less so with respect to overall crystal orientation. Vickers microhardness measurements of the root dentin are essentially the same on the three orthogonal planes with respect to the incremental plane. Knoop microhardness measurements are also the same on all three orthogonal planes when the major diagonal is aligned perpendicular to the collagen fibril axis preferred orientation direction. In-plane variations of up to 20% are observed in the orthogonal direction. The material is thus isotropic in the three main directions with respect to Vickers microhardness, but anisotropic in structure. This paradoxical situation is attributed mainly to the variable modes of crystal organization.

Adolescent↗
PubMed1998

In vitro expression and in vivo immunogenicity of Plasmodium falciparum pre-erythrocytic stage DNA vaccines.

DNA vaccine plasmids were constructed that encoded four pre-erythrocytic antigens from the human malaria parasite Plasmodium falciparum: circumsporozoite protein (PfCSP); sporozoite surface protein 2 (PfSSP2); carboxyl terminus of liver stage antigen 1 (PfLSA-1 c-term); and, exported protein 1 (PfExp-1). Antigen expression was evaluated in vitro by immunoblot analysis of tissue culture cells following transient transfection with each plasmid. Clearly detectable levels of expression depended upon, or were markedly enhanced by, fusion of the antigen encoding sequences in-frame with the initiation complex and peptide leader sequence of human tissue plasminogen activator protein. Mice injected with these plasmids produced antigen specific antibody and cytotoxic T lymphocyte responses. However, the magnitudes of the responses were not always predicted by the in vitro expression assay. The results of this study provided the basis for further testing of these plasmids in primates and the formulation of multi-component pre-erythrocytic DNA vaccines for efficacy testing in human volunteers.

Amino Acid Sequence↗
PubMed1998

Detection of p53 gene mutations in human leukemia by PCR-SSCP analysis and direct nucleotide sequencing.

OBJECTIVE: To look for mutations of the p53 gene in leukemic patients and study the relationship between abnormalities in p53 gene and leukemogenesis. METHODS: The peripheral blood and Bone Marrow Samples were collected from 36 patients with various leukemia types including 14 cases of lymphocytic leukemia [8 cases of acute lymphocytic leukemia (ALL), 4 cases of chronic lymphocytic leukemia (CLL), 2 cases of hairy cell leukemia (HCL)] and 22 cases of myelocytic leukemia [11 cases of acute nonlymphocytic leukemia (ANLL), 11 cases of chronic myelocytic leukemia (CML)]. DNA structures of exon 5-8 of the p53 gene were scanned by PCR-SSCP (single strand conformation polymorphism analysis of polymerase chain reaction products). The appropriate DNA fragments were amplified, Purified and sequenced directly. RESULTS: By PCR-SSCP analysis, shifts in electrophoretic mobility of the p53 gene were detected in 3 of 14 patients with lymphocytic leukemia (2 ALL and 1 CLL), but none in 22 patients with myelocytic leukemia including one in blastic crisis. Direct nucleotide sequencing in one patient with ALL showed transition of CTG to CAG at codon 257 of exon 7, resulting in a change of its encoded amino acids from aspartic acid to valine. To our knowledge, the mutation at this codon has not been previously reported hitherto. CONCLUSIONS: The p53 gene mutations are specifically associated with lymphocytic leukemia. Alternations of the p53 gene may play a certain role in leukemogenesis in some cases of lymphocytic leukemia.

Exons↗
PubMed1998

The effect of bu shen sheng xue fang on beta-thalassemia at gene level.

Isoelectrofocusing electrophoresis, PCR-SSCP analysis with DNA direct sequencing and RT-PCR were used to analyze the constituents of hemoglobin, determine the pattern of globin gene mutation, and detect its mRNA transcription extent. The results indicated that Bu Shen Sheng Xue Fang (BSSXF) significantly increased the contents of hemoglobin (Hb) and fetal hemoglobin (HbF), and the chain ratio in patients with beta-thalassemia. The drug is markedly effective in heterozygous, but not effective in homozygous or genetic compound patients. It was suggested that the beta-globin gene defects were compensated by elevating the gamma/beta + gamma ratio, promoting the transcription and expression of gamma-globin gene in synthesizing HbF.

Adolescent↗
PubMed1998

[Simultaneous assay of Ca(2+)-ATPase and Na+, K(+)-ATPase activities of osteoblast rat by malachite green colorimetic method].

The aim of this study was to find a method to measure simultaneously the activities of Ca(2+)-ATPase and Na+, K(+)-ATPase of rat osteoblast membrane. In this test, Ca(2+)-ATPase and Na+, K(+)-ATPase released inorganic phosphate (Pi) from ATP, and Pi was determined by colorimetric method using malachite green dye to show ATPase activities. Ca2+ concentration and osteoblast culture generation were important factors affecting ATPase activities. Ca2+ could elevate membrane ATPase activity. When Ca2+ concentration reached 40 mumol/L, ATPase activities were improved. Ca(2+)-ATPase activity decreased with the increase of osteoblast culture generation. Ca(2+)-ATPase activity was lower than Na+, K(+)-ATPase activity in osteoblast membrane. This method is simple, sensitive and reliable.

Animals↗
PubMed1998

[Manifestation and diagnostic value of MR imaging in meningeal carcinomatosis].

OBJECTIVE: To analyze the patterns of MRI manifestation, and to investigate the value of MRI in diagnosis of meningeal carcinomatosis. METHODS: Twenty three cases with meningeal carcinomtosis were analyzed. All cases had pre- and post- contrast MR imagings, typical clinical symptoms and/or positive CSF examination. RESULTS: Of the 23 cases, 22 had abnormal post-contrast meningeal enhancement. The remaining case had hydrocephalus without any enhancement. There were four abnormal MRI patterns: (1)total meningeal enhancement, (2) smooth or nodular enhancement of parts of the meninge, (3)subependymal enhancement, (4)hydrocephalus only. CONCLUSION: MRI is an important assistant method in diagnosis of meningeal carcinomatosis. Post-contrast MRI is mandatory.

Adolescent↗
PubMed1998

[Hoffmann reflex elicited by magnetic stimulation of S1 nerve roots in the diagnosis of diabetic radiculopathy].

OBJECTIVE: To determine the incidence of radiculopathy in diabetic patients neurophysiologically. METHODS: The H-reflexes were elicited by magnetic stimulation to S1 nerve root at the first sacral foramen (S1 H-reflex) in 40 normal subjects and 41 diabetic patients. The action potentials of the H-reflex were recorded from the soleus muscle. For comparison, a popliteal H-reflex (stimulated at popliteal fossa), and a regular distal sensory and motor conduction of the tibial nerves were simultaneously evaluated. RESULTS: A significant correlation of the peak interval of H wave and M wave (HMI) of the S1 H-reflex with body height and age was confirmed by multiple regression analysis in the normal subjects. The simultaneous regression of the HMI adjusted on age and body height produced the formula as 0.02 x (age) + 0.03 x (height) + 0.92. At 95% normal limits of the significant test, 40.2% HMI and 53.7% amplitude of H waves of the S1 H-reflex, 54.9% latency and 46.3% amplitude of H waves of the popliteal H-reflex, 40.2% SCV and 40.2% amplitude of sensory action potentials were diagnosed as abnormal. CONCLUSIONS: A high incidence rate of diabetic radiculopathy was confirmed to be comparable to that of proximal neuropathy and distal symmetrical sensory polyneuropathy. This suggests that diabetic neuropathy may be related to metabolic and/or vascular disorders.

Adult↗