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Biomedical subjects

Y Shen

Publications and source records attributed to Y Shen.

At least 487 records · Page 27Linked to original sources
PubMed1994

Blood monocytes from most human immunodeficiency virus type 1-infected patients do not carry proviral DNA.

In blood, the CD4+ T cells of patients with human immunodeficiency virus type 1 (HIV-1) harbor HIV-1; however, whether the CD4+ blood monocytes carry the virus is controversial. Tissue macrophages are known to be infected. To determine in blood monocytes from HIV-1-seropositive patients contain HIV-1, we separated monocytes and T-cell subsets by using monoclonal antibodies bound to magnetic beads and by monocyte adherence to glass. Monocytes were cultured with macrophage colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and interleukin-3. After 14 days in culture, cells were analyzed for the presence of HIV-1 antigen and multinucleated giant cells (MGCs). Freshly isolated cell subsets were analyzed for HIV-1 proviral DNA by PCR with modified env (SK68i and SK69i2) and gag (SK145i and SK150) primers. We found that (i) monocytes cultured without depletion of CD4+ T cells (11 of 11 patients) were HIV-1 antigen positive and showed dramatically increased spontaneous formation of MGCs (ii) monocytes cultured after depletion of CD4+ T cells (three experiments) were HIV-1 antigen negative and showed markedly decreased MGC formation, and (iii) in specimens from 14 patients subsequently analyzed by PCR, purified CD4+ T cells were positive for HIV-1 proviral DNA in all patients. In 11 of 14 patients (79%), the monocyte fractions were HIV-1 proviral DNA negative, while in the remaining 3 patients, the monocytes were positive for HIV-1 proviral DNA. In conclusion, the major reservoir for HIV-1 infection in human peripheral blood is the CD4+ T cell (14 of 14 cases).(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1994

Changing pattern of glomerular disease at Beijing Children's Hospital.

Current clinical experience with glomerular disease at a pediatric referral center in Beijing, China, was reviewed. In 1992, renal disorders accounted for 505 of a total 6,885 (7.3%) pediatric medical discharges. Acute glomerulonephritis accounted for 30% of renal diagnoses, while nephrotic syndrome accounted for 28% and Henoch-Schönlein purpura nephritis accounted for 16% of renal disease. Mortality in children with renal disease was 0.4% (two of 505). All children with acute glomerulonephritis recovered or improved at last follow-up, regardless of the relationship to a streptococcal infection. In children with uncomplicated nephrotic syndrome, 91% had a complete or partial response to corticosteroids. Nephritis developed in 81 of 278 patients with Henoch-Schönlein purpura (29%). Since 1956, a dramatic decrease in the diagnosis of acute glomerulonephritis has occurred at this pediatric hospital. Nephrotic syndrome, in contrast, has increased from 45.3 cases per year in the 1956-to-1965 decade to 146 cases annually in the period from 1986 to 1992. Similarly, Henoch-Schönlein purpura has increased from 45.3 cases annually in the 1956-to-1965 period to 238 cases per year in the past 6 years. The incidence of nephritis in patients with Henoch-Schönlein purpura has remained constant at 29% in the past 36 years. These data should be helpful for individuals and institutions who are planning educational or clinical collaborations with pediatric nephrologists in China.

Acute Disease↗
PubMed1994

[Study on Na(+)-K(+)-ATPase of the spiral ganglion neuron and acetylcholinesterase of the cochlea efferent nerve after electric stimulation in the scale media].

In this study, it was found the concentration of Na(+)-K(+)-ATPase of the spiral ganglion neuron (SGN) increased 3 months after electric stimulation (0.1 mA) for 3 hours. However, current at 1.0 mA would destroy the enzyme production mechanism of SGN. Therefore 0.4 mA might be thought as a critical level because the concentration of the enzyme decreased with just above this level of stimulation. We suggest that the appropriate intensity range of the current stimulation of SGN should be controlled from 0.1 mA-0.4 mA. Acetylcholinesterase of the cochlea efferent nerve would increase with weak current stimulation (0.1 mA) which might play an important role in the protection of SGN during ototoxicity. This experimental results led to the conclusion that Na(+)-K(+)-ATPase of the SGN could be taken as an objective indicator presenting the functional changes of SGN quantitatively.

Acetylcholinesterase↗
PubMed1994

[Unstable DNA sequence and methylation in fragile X syndrome].

Fragile X syndrome is characterized as an inherited unstable DNA sequence: the increasement of (CGG)n copy number. It suffered from the inactivation of FMR-1 (fragile X mental retardation 1), which is inhibited by amplification of (CGG)n and methylation of CpG island. The (CGG)n repeat variation in normal Chinese population was detected by PCR with sequencing gel analysis. We also analysed the amplification of (CGG)n and methylation of CpG island at Xq27.3 from 15 individuals in 6 families by Southern hybridization. These results indicate that abnormal methylation of CpG island always occurs in Fra (X) patients together with large amplification of (CGG)n. The (CGG)n could be either stable or amplified in springs of carrier females. These suggest that there would be a new genetic mechanism dynamic mutation.

Base Sequence↗
PubMed1994

Binding of typical and atypical antipsychotic agents to 5-hydroxytryptamine-6 and 5-hydroxytryptamine-7 receptors.

The authors examined the affinities of 36 typical and atypical antipsychotic agents for the cloned rat 5-hydroxytryptamine-6 (5-HT6) and rat 5-hydroxytryptamine-7 (5-HT7) receptors in transiently expressed COS-7 cells (5-HT7) or stably transfected HEK-293 cells (5-HT6 receptors). Clozapine and several related atypical antipsychotic agents (rilapine, olanzepine, tiospirone, fluperlapine, clorotepine and zotepine) had high affinities for the newly discovered 5-HT6 receptor (Kis < 20 nM). The 5-HT7 receptor bound clozapine, rilapine, fluperlapine, clorotepine, zotepine and risperidone but not tiospirone and olanzepine, with affinities less than 15 nM. In addition, several typical antipsychotic agents (chloroprothixene, chlorpromazine, clothiapine and fluphenazine) had high affinities for both the 5-HT6 and 5-HT7 receptors. Pimozide, a diphenylbutylpiperidine, had the highest affinity of all the typical antipsychotic agents tested for the 5-HT7 receptor (Ki = 0.5 nM). Three putative atypical antipsychotic agents melperone, amperozide and MDL 100907 did not bind with high affinities to either the 5-HT6 or 5-HT7 receptors (Kis > 50 nM). Several dopamine-selective antipsychotic agents (raclopride, rimcazole and penfluridol) had essentially no affinity for either the 5-HT6 or 5-HT7 receptors (Ki values > 5000 nM).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Parasitic circulating antigens in hosts with Filaria bancrofti].

The ELISA and Dot-ELISA with rabbit anti-Setaria labial-papillosa antibody were applied to determine circulating antigens of Filaria bancrofti. The total positive rate was 96% (24/25) in the sera of patients with microfilaremia from endemic areas, Anhui province. The total positive rate of urines was 60% (15/25) in the same patients. The positive rates of the milks were both 100% (4/4) in the same patients. The conformity rate was 100% and 75% respectively for positive sera and urines (15 cases), milks (4). Negative reactions were observed in the sera, urines and milks of all the 43 healthy people from non-endemic areas in Jiangsu province. Negative reactions were observed in the urines of all the 11 non-filaria cases harbouring intestinal nematodes. The positive rate detected with ELISA was 36% (4/11) in the patient sera that were negative when they were detected by Dot-ELISA. Negative reactions were detected with Dot-ELISA in the sera of all the 10 non-filaria patients infected with Paragonimus westermani. The results showed that circulating antigens of Filaria bancrofti exist not only in the serum but also in the urine and the milk.

Animals↗
PubMed1994

Relationship between microvascular structure and biological characteristics of giant cell tumour of bone.

The vascular architecture of bone giant cell tumor was observed histologically with resin cast technique and scanning electron microscopy. Three types of capillaries were noted in the tumor tissue: extruding club-like capillary in the outer zone of the tumor; sinusoid capillary running disorderly in the intermediate zone; cecum capillary in the central zone. The pattern of vascular structure was believed to be correlated with tumor growth.

Bone Neoplasms↗
PubMed1994

Integration and expression of human growth hormone gene in Caladium bicolor.

Human growth hormone (hGH) gene has been inserted into the plasmid pLGV1103 to give the recombinant plasmid pLB-9. It has been introduced into the agrobacterium containing plasmid pGV3850. The recombinant Ti plasmid pGL198(hGH) has been obtained by homologous recombination. The monocotyledon Caladium bicolor has been transferred with pGL198 (hGH) with the leaf-disk co-cultivation method, and transgenic plants have been regenerated. The results of nopaline analysis, NPT II detection Southern blot and Western blot show that the hGH gene was integrated into the genome of Caladium bicolor, and a 22-kD protein was synthesized in the transgenic plants.

Gene Transfer Techniques↗
PubMed1993

Molecular cloning and expression of a 5-hydroxytryptamine7 serotonin receptor subtype.

We have utilized the polymerase chain reaction technique to selectively amplify a G protein-coupled receptor cDNA from rat kidney proximal convoluted tubule mRNA, which exhibits high homology with previously cloned serotonin receptors. Sequencing of a full-length clone isolated from a rat hippocampal cDNA library revealed an open reading frame of 1,212 base pairs encoding a 404-residue protein with seven hydrophobic regions predicted to represent transmembrane-spanning domains. Within the transmembrane regions, this receptor was found to be 44-50% identical with various members of the 5-HT1, 5-HT5, and 5-HT6 subfamilies with lower (37-40%) homology to the 5-HT2-like receptors. Northern blots revealed a approximately 3.6-kilobase transcript localized in various brain regions with the following rank order of abundance: hypothalamus > hippocampus = mesencephalon > cerebral cortex = olfactory bulb > olfactory tubercle. Expression of this clone in COS-7 cells resulted in the appearance of high affinity, saturable binding of [3H]lysergic acid diethylamide ([3H]LSD; KD = 5 nM) and [3H]serotonin ([3H]5-HT; KD = 1 nM). Among endogenous biogenic amines, only 5-HT completely inhibited radioligand binding. The inhibition of radioligand binding by other serotonergic agents revealed a pharmacological profile that does not correlate with any previously described serotonin receptor subtype. In addition, this receptor exhibits high affinity for a number of tricyclic antipsychotic and antidepressant drugs including clozapine, loxapine, and amitriptyline. In HEK-293 cells stably transfected with this receptor, serotonin elicits a potent stimulation of adenylylcyclase activity. The distinct structural and pharmacological properties of this receptor suggests that it represents a completely novel serotonin receptor subtype, which we propose to designate 5-HT7. Based on its pharmacology and its localization to limbic and cortical regions of the brain, it is likely that this receptor may play a role in several neuropsychiatric disorders that involve serotonergic systems.

Amino Acid Sequence↗
PubMed1993

Isolation of a Miller-Dieker lissencephaly gene containing G protein beta-subunit-like repeats.

Lissencephaly (agyria-pachygyria) is a human brain malformation manifested by a smooth cerebral surface and abnormal neuronal migration. Identification of the gene(s) involved in this disorder would facilitate molecular dissection of normal events in brain development. Type 1 lissencephaly occurs either as an isolated abnormality or in association with dysmorphic facial appearance in patients with Miller-Dieker syndrome. About 15% of patients with isolated lissencephaly and more than 90% of patients with Miller-Dieker syndrome have microdeletions in a critical 350-kilobase region in chromosome 17p13.3 (ref. 6). These deletions are hemizygous, so haplo-insufficiency for a gene in this interval is implicated. Here we report the cloning of a gene (LIS-1, lissencephaly-1) in 17p13.3 that is deleted in Miller-Dieker patients. Non-overlapping deletions involving either the 5' or 3' end of the gene were found in two patients, identifying LIS-1 as the disease gene. The deduced amino-acid sequence shows significant homology to beta-subunits of heterotrimeric G proteins, suggesting that it could possibly be involved in a signal transduction pathway crucial for cerebral development.

Amino Acid Sequence↗
PubMed1993

[CT angiography of the liver].

The diagnostic efficacy of CT arterial portography (CTAP) for the hepatic tumors has been established. We developed the double-phase incremental CTAP (DP-CTAP) using a fast CT scanner, by which the double-phase scanning of the whole liver was made during a single contrast administration. The DP-CTAP was performed in 9 cases of hepatic diseases, and was useful for the lesion detection and improvement of the visualization of the liver vasculatures. The maximum density projection angiogram of the portal and hepatic veins was easily made by DP-CTAP images, and useful for three dimensional understanding of the liver vasculatures and the detection of the vascular abnormalities.

Humans↗
PubMed1993

RNA structural requirements for RNA binding, replication, and packaging in the yeast double-stranded RNA virus.

Several sites of interaction with viral proteins have been mapped in the plus strand of the Saccharomyces cerevisiae double-stranded RNA virus, ScV. These include a site necessary and sufficient for viral particle binding to plus strands (VBS) and a site necessary and sufficient for interference with replication of viral plus strands (INS). We show that the INS and VBS are identical and that they are necessary and sufficient for packaging. One of the viral RNAs has two adjacent VBS, which have additive INS activity. The second VBS has similar affinity for viral particles as the first but its complex with particles exhibits faster dissociation. Binding to the two sites in the viral RNA is independent but equivalent. This may mean two recognition sites per particle. This is what would be expected for two molecules of the protein thought to be responsible for sequence specific recognition, the cap-pol fusion polypeptide, per particle. Comparison of the secondary structures of several binding sites, as determined by site-directed mutagenesis and by ribonuclease mapping of single- and double-stranded regions, reveals a requirement for a specific loop sequence and two stem regions, in which there is no sequence specificity. Contrary to what was described in previous work, a bulge loop, but not a "bulged" A residue is necessary for binding of the second VBS. A minimal region of 30 bases is enough to cause both packaging and replication.

Base Sequence↗
PubMed1993

Molecular neurobiology of dopaminergic receptors.

Table I summarizes the properties of all of the dopamine receptors that have been cloned to date. Thus far, five different genes encoding pharmacologically distinct receptors have been identified and isolated. Based on their structural, pharmacological, and functional similarities, two of these, D1A and D1B (or D1 and D5), comprise the D1 subfamily. D2, D3, and D4 receptors represent a D2 subfamily whose members are also structurally and pharmacologically similar. In fact, given these considerations, it has been suggested that the D2, D3, and D4 receptors be termed the D2A, D2B, and D2C receptors, respectively, in recognition of their D2-like properties. Given the unexpected heterogeneity of the dopaminergic receptor system, it is logical to ask if there are other dopamine receptor subtypes remaining be identified. This seems probable, as the characteristics of the cloned subtypes do not match all of the properties of some dopamine receptors which have been previously investigated. For instance, there is extensive evidence that "D1-like" dopamine receptors exist which are linked to the activation of phospholipase C, phosphatidylinositol turnover, and Ca2+ mobilization. Dopamine, as well as several "D1-selective" agonists, has been shown to stimulate phosphatidylinositol turnover in both brain slices and kidney membranes (Felder et al., 1989; Undie and Friedman, 1990; Vyas et al., 1992), and injection of striatal mRNA into Xenopus oocytes leads to dopamine-stimulated phosphatidylinositol turnover and Ca2+ mobilization (Mahan et al., 1990). These dopamine receptors might be analogous to the alpha 1-adrenergic receptors which stimulate phospholipase C activity and might define a third distinct subfamily of dopamine receptors. There is also evidence for additional members of the D2 subfamily of receptors. Using gene transfer methods, a receptor with D2-like pharmacology has been identified and expressed but not yet sequenced (Todd et al., 1989). Also, a D2-related receptor has been characterized in kidney inner medulla membranes (Huo et al., 1991). It thus appears that there may be more dopamine receptor subtypes yet to be discovered.

Amino Acid Sequence↗