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Biomedical subjects

J Zhu

Publications and source records attributed to J Zhu.

At least 235 records · Page 13Linked to original sources

Efficient gene transfer to airway epithelium using recombinant Sendai virus.

Clinical studies of gene therapy for cystic fibrosis (CF) suggest that the key problem is the efficiency of gene transfer to the airway epithelium. The availability of relevant vector receptors, the transient contact time between vector and epithelium, and the barrier function of airway mucus contribute significantly to this problem. We have recently developed recombinant Sendai virus (SeV) as a new gene transfer agent. Here we show that SeV produces efficient transfection throughout the respiratory tract of both mice and ferrets in vivo, as well as in freshly obtained human nasal epithelial cells in vitro. Gene transfer efficiency was several log orders greater than with cationic liposomes or adenovirus. Even very brief contact time was sufficient to produce this effect, and levels of expression were not significantly reduced by airway mucus. Our investigations suggest that SeV may provide a useful new vector for airway gene transfer.

Adenoviridae↗

Inverse agonism and neutral antagonism at a constitutively active alpha-1a adrenoceptor.

We have studied the antagonist action of prazosin and KMD-3213 in a constitutively active mutant of the human alpha-1a adrenoceptor in which Ala(271) was substituted to Thr and was expressed in CHO cells. Inverse agonism was characterized by up-regulation of receptor density, a decrease in basal GTPgammaS binding, and a reduction in basal inositol-1,4,5-trisphosphate (IP(3)) level. According to the above criteria, prazosin acted as an inverse agonist, whilst KMD-3213 behaved as a neutral antagonist. Compared with the wild-type receptor, mutant receptor exhibited single affinity sites for [(3)H]-prazosin, [(3)H]-KMD and the non-radioactive ligands tested, and displayed significantly higher affinities for several agonists but not for the two antagonists. Administration of KMD-3213 to prazosin-treated CHO cells expressing the mutant receptor reversed the inverse agonism of prazosin resulting in rapid increases in cellular IP(3), in intracellular [Ca(2+)] and in the rate of extracellular acidification. These results indicated that a neutral antagonist can reverse the action of an inverse agonist at the receptor site. The distinct properties of inverse agonist and neutral antagonist in affecting receptor function may be important for the clinical use of such antagonists.

Adrenergic alpha-1 Receptor Antagonists↗

Targeting gene expression to tumor cells with loss of wild-type p53 function.

The tumor suppressor protein p53 is a transcription factor that can positively regulate the expression of critical target genes involved in negative control of cell growth or induction of apoptosis; p53 is also able to suppress the transcription of other genes by virtue of its ability to bind components of the basal transcription machinery. Over 50% of human tumors are characterized by p53 mutations that result in a loss of wild-type p53 (wtp53) function in the transcriptional control of these target genes. We have exploited this loss of p53 function in the regulation of gene transcription to develop a novel gene therapy strategy that maximizes expression of the potential therapeutic gene in tumors while simultaneously down-regulating the same gene in normal cells. In one construct (unit I), the potential therapeutic gene (in this case represented by a luciferase reporter) is placed under the control of a promoter such as the heat shock protein 70 gene promoter, which is repressed by wtp53 but overexpressed in many tumor cells with defective p53 function. Residual expression of the reporter in normal cells is repressed by cotransfection of another construct (unit II) consisting of a repressor of unit I under the control of a promoter that is activated by wtp53 expression. Unit II contains a promoter with a consensus wtp53 binding site driving a transcriptional repressor or an antisense construct for the gene in unit I. Our results suggest that this dual control approach may represent a strategy with wide applications in the field of cancer gene therapy.

Feasibility Studies↗

Intranasal administration of recombinant mouse interleukin-12 increases inflammation and demyelination in chronic experimental autoimmune neuritis in Lewis rats.

To examine whether interleukin (IL)-12 modulates ongoing chronic experimental autoimmune neuritis (EAN), we evaluated the effects of recombinant mouse IL-12 (rmIL-12) in Lewis rats with chronic EAN, induced by immunization with P0 peptide (180-199) plus complete Freund's adjuvant. Rats were treated intranasally with either 0.1 or 1 microg/rat/day rmIL-12 for 6 days from the onset of clinical chronic EAN, on days 5-10 postimmunization (p.i.). Only high-dose rmIL-12 exacerbated chronic EAN. This clinical effect was associated with higher numbers of inflammatory cells and more severe demyelination in sciatic nerve sections on days 15 and 80 p.i. compared with low-dose rmIL-12-treated rats and phosphate-buffered saline (PBS)-treated control rats. High-dose rmIL-12 increased significantly the lymph node mononuclear cell proliferation in response to P0 peptide 180-199 and IFN-gamma production in the sciatic nerves. These data indicate that intranasally administered IL-12 acts as a proinflammatory cytokine in chronic EAN. Effective inhibition of IL-12 in vivo could be considered for therapeutic use in chronic inflammatory demyelinating polyradiculoneuropathy.

Administration, Intranasal↗

Augmented expression of daintain/allograft inflammatory factor-1 is associated with clinical disease: dynamics of daintain/allograft inflammatory factor-1 expression in spleen, peripheral nerves and sera during experimental autoimmune neuritis.

Experimental autoimmune neuritis (EAN) is an animal model of Guillain-Barré syndrome, characterized by inflammation and demyelination of the peripheral nervous system (PNS). Daintain/allograft inflammatory factor-1 (daintain/AIF-1) is a novel interferon-gamma-inducible protein expressed by macrophages during organ specific autoimmune diseases. To study the involvement of daintain/AIF-1 in EAN we induced EAN in Lewis rats by immunizing with bovine PNS myelin (BPM) and complete Freund's adjuvant (CFA). The expression of daintain/AIF-1 was examined in the spleen, peripheral nerves and sera during the course of EAN by immunohistochemistry and radioimunoassay (RIA). The expression of daintain/AIF-1 in the spleen and in the sciatic nerves peaked at the preclinical stage (day 7 post immunization (p.i.)) and at the height (day 15 p.i.) of clinical EAN, consistent with a disease promoting role for daintain/AIF-1. Daintain/AIF-1 expressing cells represented a subset of ED1+ or CD11b/c+ mononuclear cells. A significant increase of daintain/AIF-1-like immunoreactivity in sera occurred at the preclinical stage of EAN. Taken together, these data indicate that daintain/AIF-1 may play a proinflammatory role in the pathogenesis of EAN.

Animals↗

Two-tailed versus one-tailed base rates of discrepancy scores in the WAIS-III.

Tables included in the WAIS-III report the frequency of discrepancies between IQ and index scores independent of the directionality of the score. If an examiner does not have any a priori hypothesis about which skill may be more developed and which skills may be weaknesses, it is appropriate to use these tables as they are. In this case the examiner would be looking for unusually large discrepancies between scores irrespective of direction. When an examiner has a hypothesis about which skills may be weaknesses and strengths for an individual, the frequencies that are based upon an absolute value of the discrepancy will cause examiners to overestimate the frequency of the occurrence of the discrepancy score in question. Sattler and Ryan (1998) and Tulsky, Zhu, and Vasquez (1998) suggested dividing the frequencies reported in the WAIS-III tables in half to obtain the correct base rate. This suggestion is tested in this paper. New observed frequency tables were derived from the WAIS-III and WMS-III standardization samples and these frequencies were compared against the estimated frequencies using the method described by Sattler and Ryan (1998) and Tulsky et al. (1998). The differences between these two methods were calculated and are, for the most part, insignificant. In light of the similarity between the methods, the implications of using observed frequencies versus estimated frequencies is discussed.

Adolescent↗

Co-norming the WAIS-III and WMS-III: Is there a test-order effect on IQ and memory scores?

Test-order effect on the WAIS-III and WMS-III scores was evaluated using the WMS-III standardization sample. Participants completed the standardization editions of the WAIS-III and WMS-III in one session, with the tests administered in roughly counterbalanced order. Repeated measure MANOVA analyses were conducted to determine if there was an overall test-order effect for subtest, index, or IQ scores. No significant test-order effects were found for either the WAIS-III index or IQ scores or for the WMS-III index scores. At the subtest level, the majority of the WAIS-III and WMS-III subtests did not show a significant test-order effect. The exceptions were Digit Span and Digit Symbol-Coding on the WAIS-III and Faces II and Logical Memory II on the WMS-III. Although statistically significant test-order effects were found on these subtests, the effect sizes were small. This study indicates that the test-order effect is not a potential threat to the internal validity of the WAIS-III and WMS-III normative data. The practical implications of the current study are discussed.

Adolescent↗

Could test length or order affect scores on letter number sequencing of the WAIS-III and WMS-III? Ruling out effects of fatigue.

The Letter Number Sequencing subtest of the WAIS-III and WMS-III was administered at the end of the standardization edition of the WMS-III. It was not administered as part of the WAIS-III standardization battery. Nevertheless, the subtest was included in the published version of the WAIS-III. This study examines differences between examinees administered the Letter Number Sequencing subtest at three different times during a psychological battery: (1) as part of the published battery, (2) as part of the WMS-III when the WMS-III was administered as the first test in a sequence, and (3) as part of the WMS-III standardization when the WAIS-III was administered immediately preceding the WMS-III. The participants were 372 examinees ( n = 124 in each condition) who were matched on key demographic variables. A repeated measures MANOVA yielded no difference in subtest scores when administered in any of these conditions. The results show no evidence of fatigue or ordering effects on the Letter Number Sequencing subtest.

Adult↗

A field study on downwind odor transport from swine facilities.

This paper presents field data to illustrate the characteristics of downwind odor dispersion. A total of eight swine facilities were studied in this project and power functions were found to be an appropriate description of the pattern of downwind odor transport for both swine buildings and manure storage lagoons and tanks. The coefficients of correlation for the power regressions ranged from 0.75-0.87. It was found that swine buildings have the potential of generating more odor than manure storage facilities such as lagoons and tanks and thus could be the major odor sources causing downwind odor nuisance. Therefore, to maintain the building clean should be highly recommended as swine producers' best management practice. For earthen basins, the odor strength was reduced by 80% at about 250-meter distance from the source. While for the swine building, a 50% of reduction in odor strength was observed at the same distance. The study did not show any advantages of using lagoons over concrete (or steel) manure tanks in terms of reducing downwind odor concentrations. Land application of manure did not cause persistent downwind odor problems.

Agriculture↗

Seepage from deep bedded and poultry litter systems.

The work reported indicates that there could be a potential of ground water pollution by NO3-N from turkey facilities built on both sandy and clay soils. At four different depths (30.54, 61.08, 91.62, and 122.16 cm), the NO3-N levels for the clay soil were 1572, 497, 66, and 28 ppm, and those for the sandy soil were 293, 425, 324, and 164 ppm, respectively. No significant P increases were observed but there did exist a significant increase of K in the topsoil for both clay and sandy turkey structures. The results show that swine hoop houses with less than three or four years of age may not pose a threat to groundwater pollution due to the leaching of nutrients. The only dairy feedlot sampled in this study, although it has been used for more than 20 years, did not show leaching of NO3-N and P. However, it did show a significantly elevated concentration of potassium in the topsoil, as compared to the background sample. More sites should be investigated to verify this.

Animal Feed↗

An alternative-exon database and its statistical analysis.

We compiled a comprehensive database of alternative exons from the literature and analyzed them statistically. Most alternative exons are cassette exons and are expressed in more than two tissues. Of all exons whose expression was reported to be specific for a certain tissue, the majority were expressed in the brain. Whereas the length of constitutive exons follows a normal distribution, the distribution of alternative exons is skewed toward smaller ones. Furthermore, alternative-exon splice sites deviate more from the consensus: their 3' splice sites are characterized by a higher purine content in the polypyrimidine stretch, and their 5' splice sites deviate from the consensus sequence mostly at the +4 and +5 positions. Furthermore, for exons expressed in a single tissue, adenosine is more frequently used at the -3 position of the 3' splice site. In addition to the known AC-rich and purine-rich exonic sequence elements, sequence comparison using a Gibbs algorithm identified several motifs in exons surrounded by weak splice sites and in tissue-specific exons. Together, these data indicate a combinatorial effect of weak splice sites, atypical nucleotide usage at certain positions, and functional enhancers as an important contribution to alternative-exon regulation.

Algorithms↗

The ocular pharmacokinetics of ketanserin and its metabolite, ketanserinol, in albino rabbits.

Ketanserin, a hypotensive drug with 5-HT2 receptor antagonism, when administered by topical infusion of a 0.25% w/v solution by corneal and scleral applications, was found to lower intraocular pressure with four times more activity than its metabolite, ketanserinol. Drug and metabolite were measured periodically in the corneal epithelium, corneal stroma/endothelium, aqueous humor, iris/ciliary body, conjunctiva, sclera and lens during the infusion period (0-120 min) and the postinfusion period (120-240 min) using a fluorometric reversed-phase HPLC assay developed and verified for the research. The infusion results showed that drug entered the eye by both the corneal and scleral routes. Lateral diffusion occurred between the conjunctiva and corneal epithelium. Drug and metabolite were also detected in the untreated fellow eyes, suggesting contralateral systemic redistribution. In vitro metabolism was studied and found to occur in the corneal epithelium, iris/ciliary body and bulbar and palpebral conjunctiva but not in the corneal stroma/endothelium, aqueous humor and sclera. From noncompartmental analysis, zero-order infusion rate constants, first-order absorption constants, mean residence time, volumes of distribution at steady state (Vss) and clearance (Cle) were obtained using equations specific to the topical infusion method. Vss and Cle of aqueous humor (0.972 ml and 13.55 microl/min) were greater than aqueous humor volume (0.311 ml) and turnover rate (4.7 microl/min).

Administration, Topical↗

Plan-view imaging of oxygen-induced reconstruction on Ag(110) surface. I. The possibility of imaging surface oxygen

Surface reconstruction on Ag(110) induced by oxygen adsorption was studied by the plan-view imaging technique of high-resolution electron microscopy (HREM). Systematic multislice simulations were carried out to find the optimal experimental conditions for imaging the surface oxygen. It was found theoretically that there exist a series of characteristic values of objective lens defoci and sample thicknesses under which the surface and the bulk can be imaged clearly and simultaneously. These optimal imaging conditions were used to interpret the experimental micrographs. While the basic features of the surface reconstruction of O/Ag(110) in the HREM images are consistent with those revealed by scanning tunnelling microscopy (STM), there are some new features that have not been reported with STM. These phenomena give some evidence to the existence of subsurface oxygen.

Journal Article↗

Plan-view imaging of oxygen-induced reconstruction on Ag(110) surface. II. Effect of high-energy electron thinning

The feasibility and the limitation of the 'high-energy electron thinning' method for the production of surface-science-grade samples in situ in the electron microscope are studied. Exploiting the electron beam supplied by high-voltage electron gun in electron microscope, this method can be readily realized. An obvious advantage of this method is that we can monitor the sample surface concurrently. However, this sample preparation method depends strongly on the sample material and the local environment within the electron microscope. Factors relating to the electron thinning speed are briefly discussed.

Journal Article↗

Measurement of Debye-Waller factors in Co3Ti by quantitative CBED

The Debye-Waller factors (DWFs) of Co and Ti atoms in Co3Ti have been obtained by quantitative convergent-beam electron diffraction (QCBED). They are B(Co) = 0.20-0.24 and BTi = 0.41-0.43 A2 in Co3Ti at room temperature. A modified simulated-annealing algorithm and its parallel algorithm were employed to obtain reliable results efficiently.

Journal Article↗

A promoter region binding protein and DNA gyrase regulate anaerobic transcription of nifLA in Enterobacter cloacae.

Our work provides evidence that a sequence characteristic of FNR binding sites, when interacted with by a trans-acting factor, activates anaerobic transcription of the nifLA operon in Enterobacter cloacae. DNA gyrase activity has been found to be important for the anaerobic transcription of the nifLA promoter. Our results suggest that anaerobic regulation of the nifLA operon is mediated through the control of the promoter region-binding trans-acting factor at the transcriptional level, while DNA supercoiling functions in providing a topological requirement for the activation of transcription.

Anaerobiosis↗

The right end of the vir region of an octopine-type Ti plasmid contains four new members of the vir regulon that are not essential for pathogenesis.

We sequenced the virD-virE, virE-virF, and virF-T-DNA intergenic regions of an octopine Ti plasmid. Four newly described genes were induced by the vir gene inducer acetosyringone, two of which are conserved in the nopaline-type Ti plasmid pTiC58. One gene resembles a family of phosphatase genes. Each of these genes is dispensable for tumorigenesis.

Acetophenones↗