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Biomedical subjects

J Qi

Publications and source records attributed to J Qi.

At least 109 records · Page 6Linked to original sources
PubMed1996

Polymorphism of angiotensin I converting enzyme gene in the older Chinese: linked to ambulatory blood pressure levels and circadian blood pressure rhythm.

This study was undertaken to evaluate the association of polymorphism of angiotensin I converting enzyme (ACE) gene with causal and ambulatory blood pressure in the Chinese population. Genomic DNA was amplified by polymerase chain reaction (PCR) using primers flanking the polymorphic region in intron 16 of the ACE gene. Alleles were detected on agarose gels stained with ethidium bromide. Causal blood pressure was measured in the 133 normotensive and 122 essential hypertensive subjects; of the essential hypertensive subjects, 65 patients underwent non-invasive ambulatory blood pressure. There was no significant difference of ACE genotype and allele frequencies between the hypertensive and normotensive subjects. Non-significant differences were demonstrated in gender, age, causal blood pressure according to the ACE gene genotypes in the 65 patients who underwent non-invasive ambulatory blood pressure; however, effects of the ACE gene genotypes were observed on the derivatives of ambulatory blood pressure, including sleeping blood pressure levels and circadian blood pressure rhythm (p < 0.05). We suggest that insertion/deletion polymorphism of the ACE gene should be associated with blood pressure and ambulatory blood pressure might be superior to causal blood pressure at the molecular level.

Aged↗
PubMed1996

Selection of trypsin inhibitors in phage peptide library.

The newly developed techniques of peptide libraries have become a conventional and efficient method in screening ligands of proteins of interest. We present here the successful results of selection of trypsin inhibitors in a phage hexapeptide library. After affinity selection and activity assay, peptide sequences, deduced from DNA sequencing of the phage peptides with the most striking trypsin activity, share some common features with trypsin inhibitors reported. All of the phage peptides selected out and those native and synthetic trypsin inhibitors reported are composed of three parts: (a) positively charged part (Arg, Lys or their analogs); (b) polar part that may form hydrogen bonds with Ser in the active site of trypsin; (c) hydrophobic part that interacts with the nonpolar region of trypsin active site.

Amino Acid Sequence↗
PubMed1996

[Establishment of human amnion cell mutagenesis system by using a shuttle vector pS189].

Using transient shuttle vector pS189, we established a subclone human amnion cell (FL) mutagenesis detection system, and we detected the mutation specificity of N-methy-N'-nitro-N-nitrosoguanidine (MNNG) in this system. The spontaneous mutant frequency of target gene supF was 1.7 x 10(-5) and MNNG-induced mutant frequency was increased with dosage. The results from 0.8% agarose gel electrophoresis, PCR, PCR-single strand conformation polymorphism (PCR-SSCP) analysis showed that MNNG-induced 89% mutants were point mutants. These results indicated that this system can be used to detect and study the mutagenesis mechanism of potential mutagens.

Amnion↗
PubMed1995

Fibrin activation of vascular endothelial cells. Induction of IL-8 expression.

Fibrin deposition and leukocyte accumulation are classic histopathologic hallmarks of acute and chronic inflammation. Although both of these processes are common to inflammatory processes, surprisingly little is known about the interrelationship between fibrin deposition and leukocyte accumulation. We hypothesized that: 1) fibrin can regulate inflammation by directly inducing leukocyte chemotactic factor (LCF) expression from vascular endothelial cells (VEC), and 2) this fibrin-induced VEC expression of LCF would enhance leukocyte recruitment seen in acute and chronic inflammation. To test this hypothesis, we developed an in vitro model system of in situ polymerization of fibrin on isolated bovine pulmonary artery endothelial cells in culture. In the initial phase of our studies, we found that fibrin induced a time- and dose-dependent expression of leukocyte migration activity from VEC. Checkerboard analysis demonstrated that the leukocyte migration activity present in the fibrin-stimulated VEC culture supernatant was truly chemotactic in nature. In an effort to begin to characterize this chemotactic activity, we demonstrated that this fibrin-induced LCF activity was 1) protein dependent, 2) not derived from fibrin(ogen), and 3) had an apparent m.w. of 6 to 12 kDa. Our further studies demonstrated that fibrin was a potent stimulus for IL-8 Ag expression from the VEC. Thus, these studies clearly demonstrate that fibrin has the capability to induce leukocyte chemotactic activity in general, and IL-8 activity specifically, from VEC. These studies support our hypothesis that fibrin is an important activator of vascular endothelial cells in vivo.

Animals↗
PubMed1995

A region-specific microdissection library for human chromosome 2p23-->p21 and the analysis of an interstitial deletion of 2p21.

A region-specific library of human chromosome 2p23-->p21 was constructed using microdissection and microcloning techniques. Analysis of 94 single-copy microclones from the library showed that 64% were derived from the dissected region. Ten microclones were further mapped to the 2p21 region using a patient with an interstitial deletion of 2p21 and displaying holoprosencephaly, an abnormal embryonic development in midbrain and midface.

Animals↗
PubMed1994

Isolation and refined regional mapping of expressed sequences from human chromosome 21.

To increase candidate genes from human chromosome 21 for the analysis of Down syndrome and other genetic diseases localized on this chromosome, we have isolated and studied 9 cDNA clones encoded by chromosome 21. For isolating cDNAs, single-copy microclones from a chromosome 21 microdissection library were used in direct screening of various cDNA libraries. Seven of the cDNA clones have been regionally mapped on chromosome 21 using a comprehensive hybrid mapping panel comprising 24 cell hybrids that divide the chromosome into 33 subregions. These cDNA clones with refined mapping positions should be useful for identification and cloning of genes responsible for the specific component phenotypes of Down syndrome and other diseases on chromosome 21, including progressive myoclonus epilepsy in 21q22.3.

Adult↗
PubMed1994

Analysis of the complete genome of smallpox variola major virus strain Bangladesh-1975.

We analyzed the 186,102 base pairs (bp) that constitute the entire DNA genome of a highly virulent variola virus isolated from Bangladesh in 1975. The linear, double-stranded molecule has relatively small (725 bp) inverted terminal repeat (ITR) sequences containing three 69-bp direct repeat elements, a 54-bp partial repeat element, and a 105-base telomeric end-loop that can be maximally base-paired to contain 17 mismatches. Proximal to the right-end ITR sequences are another seven 69-bp elements and a 53- and a 27-bp partial element. Sequence analysis showed 187 closely spaced open reading frames specifying putative major proteins containing > or = 65 amino acids. Most of the virus proteins correspond to proteins in current databases, including 150 proteins that have > 90% identity to major gene products encoded by vaccinia virus, the smallpox vaccine. Variola virus has a group of proteins that are truncated compared with vaccinia virus counterparts and a smaller group of proteins that are elongated. The terminal regions encode several novel proteins and variants of other poxvirus proteins that potentially augment variola virus transmissibility and virulence for its only natural host, humans.

Animals↗
PubMed1994

A region-specific microdissection library for human chromosome 2p23-p25 and the analysis of an interstitial deletion of 2p23.3-p25.1.

A region-specific library for human chromosome 2p23-p25 was constructed using microdissection and polymerase chain reaction (PCR)-mediated microcloning techniques. This library is large, comprising 300,000 recombinant microclones. The insert sizes range between 50-600 base pairs (bp) with a mean of 200 bp. About 50%-60% of the clones contain unique or very low copy number sequence inserts as determined by their weak or no hybridization to total human DNA. A subset of 48 microclones that did not hybridize to total human DNA after colony hybridization was analyzed, and 26 (54%) clones were shown to contain single-copy inserts and hybridize to human chromosome 2 DNAs, indicating that they are human chromosome 2 specific. The human genomic fragments identified by these clones after cleavage with HindIII have also been characterized. The single-copy microclones were used to analyze an interstitial deletion in the 2p23.3-p25.1 region--46,XY, del(2) (pter-->p25.1::p23.3-->qter)--previously reported in a patient with severe growth and mental retardation and multiple anomalies. Of the 26 microclones analyzed, 14 clones were mapped to the deletion region. The availability of the 2p23-p25 region-specific library and the probes derived from the library should be valuable for fine structure physical mapping analysis and the cloning of disease-related genes localized to the region. These studies also demonstrate the efficiency with which useful probes can be quickly generated for genome studies and for positional cloning.

Animals↗
PubMed1994

Construction and characterization of region-specific microdissection libraries and single-copy microclones for short arm of human chromosome 2.

The short arm of human chromosome 2, comprising approximately 93 million bp, has been divided into four regions to construct region-specific microdissection libraries to facilitate physical mapping and gene cloning. These four regions include 2p23-p25 (designated 2P1), 2p21-p23 (2P2), 2p14-p16 (2P3), and 2p11-p13 (2P4). Together with three previously constructed microdissection libraries of 2P1, 2P2 and 2P4, a fourth library for the region 2p14-p16 (2P3) has been constructed and characterized to complete all four region-specific libraries for the entire 2p. The 2P3 library is very large, potentially comprising 1,000,000 recombinant microclones with insert sizes ranging between 50 and 800 bp and a mean of 250 bp. Approximately 40% of the microclones contain unique sequences. Of the 77 single-copy microclones analyzed, 66 clones (86%) hybridized to both human and chromosome 2 DNAs, indicating that they were derived from human and are chromosome 2 specific. The hybridizing HindIII genomic fragments for the 66 microclones have also been determined.

Blotting, Southern↗
PubMed1994

Region-specific microdissection library and single-copy microclones for human chromosome 2p11-p13.

We report the construction and characterization of a region-specific microdissection library for human chromosome 2p11-p13. This library (designated 2P4 library) is large, comprising 600,000 recombinant microclones. Thirty to 40% of the clones contain unique sequences. The insert sizes range from 100 to 800 bp, with a mean of 380 bp. A subset of the microclones was selected, based on their weak or no hybridization to total human DNA, for further analysis. Of 50 single-copy microclones analyzed, 35 clones (70%) were derived from human and are chromosome 2-specific. The insert sizes and the hybridizing genomic HindIII fragments of these clones were also determined. The 2P4 microdissection library and the single-copy microclones from the library are useful in preparing STS (sequence-tagged site) to isolate corresponding YAC (yeast artificial chromosome) or other clones with large inserts and for isolating region-specific cDNA clones as candidate genes for cloning disease-related genes assigned to this region.

Chromosomes, Human, Pair 2↗
PubMed1994

Effect of low dose radiation on intracellular calcium and protein kinase C in lymphocytes.

It is first reported in the present paper that whole-body irradiation (WBI) with low dose X-rays could increase intracellular calcium ions ([Ca2+]i) and stimulate protein kinase C (PKC) activity of mouse lymphocytes. Following WBI of male Kunming mice with 75 mGy X-rays at a dose rate of 12.5 mGy/min the mobilization of [Ca2+]i with Con A in CD4+ and CD8+ Cells in the thymus and spleen was potentiated and the amplitude of [Ca2+]i mobilization in thymocytes in response to anti-CD3 monoclonal antibody increased with time from 4 to 24 h following low dose radiation. The PKC activity in the homogenate of spleen was markedly stimulated 12 h after WBI with 75 mGy, reaching its peak value at 24-48 h and coming down to lower than normal on day 7. However, the PKC activity in the separated T lymphocytes reached its peak value at 12 h and that in the B lymphocytes reached its peak value on day 4, both coming down to below control on day 7. The implications of this facilitation of signal transduction in T lymphocytes in the mechanism of immunoenhancement after low dose radiation were discussed.

Animals↗
PubMed1993

Reduction in glial fibrillary acidic protein mRNA abundance induced by (-)-deprenyl and other monoamine oxidase B inhibitors in C6 glioma cells.

Gliosis is commonly observed in the CNS following tissue damage, and it also occurs in aging and in many neurodegenerative diseases. Glial fibrillary acidic protein (GFAP) accumulation is a prominent feature of astrocytic gliosis. An inhibition or delay in GFAP synthesis could mitigate scar formation and thus reduce the formation of a physical barrier. The consequence of this would be to allow neurons and oligodendrocytes to reestablish a functional environment. (-)-Deprenyl, a specific monoamine oxidase (MAO) B inhibitor, has been used as an effective antiparkinsonian drug, and it has been reported to possess neuroprotective and neurorescue properties. Using northern and slot blots to detect GFAP mRNA in C6 glioma cells, we have demonstrated that (-)-deprenyl decreases the abundance of GFAP mRNA in a time- and dose-dependent manner. The effect seems to be specific to MAO B inhibitors because (+)-deprenyl and clorgyline exhibit no effect. This study indicates therefore that (-)-deprenyl may be useful for regulating astrogliosis following CNS injury as well as in some neurodegenerative diseases.

Animals↗