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Biomedical subjects

Y Shen

Publications and source records attributed to Y Shen.

At least 451 records · Page 25Linked to original sources
PubMed1995

The role of neuropeptides in learning and memory: possible mechanisms.

Endogenous neuropeptides such as vasopressin, adrenocorticotropin and opioids have significant effects on learning and memory. However, because of the complexity of behaviour, that is defined as 'learning' and 'memory' and, because of the limitation of current knowledge, it has been difficult to interpret these behavioural data, especially via neural mechanisms. The application of modern experimental techniques including molecular biology such as cloning and electrophysiology, such as patch-clamp, has had a significant impact upon the concepts about drugs, including neuropeptides action sites. This allows us to try to interpret some behavioural consequences influenced by neuropeptides. The data on effects of some neuropeptides on behaviours and their possible mechanisms are reviewed. Whatever the mechanisms, vasopressin, adrenocorticotropic hormone and endogenous opioids seem to have important effects upon learning and memory and these open up the possibility that drugs enhance cognitive functions or treat dementia via alteration of functions of neuropeptides. Some criteria are proposed for evaluating the validity of behavioural tests for neuropeptides.

Adrenocorticotropic Hormone↗
PubMed1995

Localization of knee joint cartilage pathology by multichannel vibroarthrography.

This paper proposes non-invasive techniques to localize sound or vibroarthrographic (VAG) signal sources in human knee joints. VAG signals from normal subjects, patients who subsequently underwent arthroscopy, and cadavers with arthroscopically-created lesions, obtained by stimulation with a finger tap over the mid-patella and swinging movement of the leg, were analyzed for time delays using cross-correlation functions for source localization. Correct results were obtained for 13 of the 14 subjects tested by finger stimulation, and for 11 of the 12 subjects whose VAG signals during swinging movement were analyzed. The techniques could be valuable in the diagnosis and treatment of knee pathology before and after joint surgery or drug therapy.

Arthroscopy↗
PubMed1995

Viruses and apoptosis.

Apoptosis is an active process of cell death that serves diverse functions in multicellular organisms, and under physiological conditions, it is tightly controlled. Many virus genomes encode gene products that modulate apoptosis, either positively or negatively, and induction of apoptosis often contributes directly to the cytopathogenic effects of the viruses. Inhibition of apoptosis by viruses, on the other hand, may prevent premature death of infected cells, thereby facilitating viral replication, spread, or persistence.

Adenoviridae↗
PubMed1995

Molecular cloning of a novel G protein-coupled receptor related to the opiate receptor family.

A cDNA clone encoding a novel G protein-linked receptor was isolated from a rat cerebral cortex cDNA library using a polymerase chain reaction-amplified cDNA fragment as a probe. This 2.4-kb clone encodes a 367 amino acid protein with seven putative transmembrane spanning domains. The protein is highly homologous to the cloned micro, delta, and kappa opioid receptors and shares with them structural features such as three glycosylation sites in the amino terminus, a cyclic AMP-dependent kinase phosphorylation site in the third cytoplasmic loop, an aspartic acid residue in the second transmembrane domain, and a palmitoylation site on the intracellular carboxy terminus. The receptor is also homologous with members of the somatostatin receptor family, yet it binds neither opiate nor somatostatin ligands. Northern blot analysis reveals two transcripts of 3.2 and 7.6 kb that are predominantly expressed in the cerebral cortex and hypothalamus. In situ hybridization analysis also shows a high abundance of mRNA in the cerebral cortex, hippocampus, amygdala, hypothalamus, thalamus, and dorsal raphe nuclei. It is suggested that the endogenous ligand for this receptor may represent a novel neuropeptide that may be closely related to the opiate peptide family.

Amino Acid Sequence↗
PubMed1995

130 kb of DNA sequence reveals two new genes and a regional duplication distal to the human iduronate-2-sulfate sulfatase locus.

Deficiency of IDs activity results in Hunter Syndrome (mucopolysaccharidosis type II), a fatal X-linked recessive disorder. We report characterization of 28 cosmids around the IDS locus in Xq28. Four overlapping cosmids have been sequenced in their entirety generating a 130-kb contig. These studies show the fine structure of the IDS gene and identify an IDS pseudogene-like structure located 20 kb distal to the active gene. Two novel genes have also been identified in this sequence, and one of these genes is also locally duplicated. Both homologs are expressed, and a number of alternative transcript products have been characterized. The presence of a highly conserved pseudogene-like structure within a larger duplicated region close to the IDS gene has significant implications for the study of mutations at this locus.

Base Sequence↗
PubMed1995

Human cytomegalovirus IE1 and IE2 proteins block apoptosis.

Human cytomegalovirus-infected fibroblasts are resistant to the induction of apoptosis by superinfection with a mutant adenovirus unable to produce the viral E1B 19-kDa protein that normally causes an E1A protein-mediated apoptotic response. Two cytomegalovirus gene products that block apoptosis were identified. The IE1 and IE2 proteins each inhibit the induction of apoptosis by tumor necrosis factor alpha or by the E1B 19-kDa-protein-deficient adenovirus but not by irradiation with UV light. Our results suggest a new physiological role for the IE1 and IE2 proteins in the human cytomegalovirus replication cycle.

Animals↗
PubMed1995

Bopindolol is a slowly dissociating beta 1-adrenoceptor antagonist when compared to other beta-blockers.

This study used radioligand binding assay methods and pharmacological experiments to examine whether bopindolol, possessing a long-lasting action in addition to potent beta-adrenoceptor antagonistic effects, is a slowly dissociating antagonist. In addition, the slow dissociation of two of its metabolites, 18-502 (4-(3-tert-butylamino-2-hydroxypropoxy)-2-methyl indole) and 20-785 (4-(3-tert-butylaminopropoxy)-2-carboxyl indole), which have potent beta-blocking activities, was also assessed. The blockade of 3H-CGP12177 binding sites in rat heart and brain induced by pindolol was readily reversed by washing, whereas this inhibition by bopindolol and 18-502 was not easily reversed by washing. In addition, specific bindings of the hearts of the treatment animals with 20-785, atenolol, (+/-)propranolol, nadolol and celiprolol and of washout were 86.7, 78.8, 77.5, 82.3 and 79.9% of the control, respectively. These blockades by the treatment of each drug and washout in the brain were, however, lower than those in the hearts. On the other hand, when the left and right atria were pretreated with propranolol, bopindolol and 18-502, the inotropic and chronotropic actions of isoprenaline were inhibited by these drugs even though they were not present in the extracellular medium. Pretreatment with 20-785, atenolol and nadolol was readily reversed for both inotropic action and chronotropic rate, and inhibition by celiprolol and pindolol remained at 25% of the control at 240 min after treatment with these drugs. A good correlation between inhibitory binding percentage in the hearts and inhibitory inotropic or chronotropic actions were observed, although it was not observed in the brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-1 Receptor Antagonists↗
PubMed1995

[Protective action of Lycium barbarum L. (LbL) and betaine on lipid peroxidation of erythrocyte membrane induced by H2O2].

H2O2 was used to induce lipid peroxidation of RBC membrane in rats to observe the protective action of different ingredients of LbL and betaine on the membrane. The result shows these ingredients cna inhibit the lipid peroxidation of RBC membrane in the following order of antioxidizing power: Fructus Lycii.LbL.dry(FL/LbL.dry) > Polysaccharide FL/LbL > Residue FL/LbL > betaine.

Animals↗
PubMed1995

[Surgical treatment of carcinoma of low rectum].

1230 cases of low rectal cancer were treated surgically from 1954 through 1990 with a resectability rate of 79.92% and a curative resectability rate of 63.98%. Among curative resections, abdomino-perineal excision accounted for 71.16% and sphincter-saving resection for 28.84%. Before 1980, 19.19% cases were treated with SSR and since 1980 it was raisen to 41.04%. In comparison of the results of group before 1980 with those since 1980, the mortality rate of curative resection was 1.56% and 0.99% respectively. The 5-year survival rate of curative resection (life table method) was 58.96% +/- 2.87% in APR and 80.39% +/- 5.06% in SSR before 1980, and 71.65% +/- 3.28% in APR and 83.82% +/- 3.46% since 1980. The local recurrence after curative resection was 13.57% in APR and 12.33% in SSR. The data showed that in properly selected cases, the outcome was better in SSR than in APR either in survival or in quality of life. The feasibility and reasonality of the SSR and the rules for selecting the operative procedures in low rectal cancer were discussed in detail.

Female↗
PubMed1995

Effects of cadmium and verapamil on ketamine-induced anesthesia in mice.

Previous studies have shown that pretreatment with cadmium and verapamil potentiated the effects of some CNS active drugs. The objective of this study was to determine the influence of these agents on ketamine anesthesia in adult male mice. Intraperitoneal administration of 300 mg ketamine/kg produced sleeping time of 40.88 +/- 2.98 min. Pretreatment with a single dose of either 3 mg cadmium/kg sc or 5 mg verapamil/kg ip alone significantly increased the duration of sleeping time (40.88 +/- 2.98 vs 55.09 +/- 4.20 and 49.01 +/- 3.09 min). Pretreatment with cadmium plus verapamil produced significant additive effects on ketamine-induced anesthesia (40.88 +/- 2.98 vs 70.32 +/- 4.64 min). Pretreatment with 3 mg cadmium/kg sc before 1 w caused a reduction in the potentiating effects of a 2nd dose of cadmium in ketamine-induced anesthesia in mice. These results indicate that prolongation of ketamine-induced anesthesia by cadmium and verapamil could be mediated either by inhibition of hepatic P450 metabolizing enzymes or neuronal calcium channels blockade. The tolerance to the potentiating effects of cadmium could be mediated by hepatic metallothionein induction and a reduction in total body cadmium burden.

Anesthesia↗
PubMed1995

Coronary artery bypass grafting in patients after failure of intracoronary stenting.

BACKGROUND: Intracoronary stents are being used to treat acute and threatened closure after percutaneous transluminal coronary angioplasty and to prevent restenosis. METHODS: The outcomes of 68 patients having coronary artery bypass grafting after stent placement were reviewed. The mean age was 60.5 +/- 9.7 years, and 71% were male. Thirty-seven percent had hypertension, 13% had diabetes, 62% had class III or IV angina, 60% had multivessel disease, and 40% had sustained a prior myocardial infarction. Fifty-three patients underwent emergency operation, 22 with hemodynamic collapse immediately after percutaneous transluminal coronary angioplasty, and 7 others required urgent revascularization within 24 hours of angioplasty. Seventeen underwent coronary artery bypass grafting for acute closure of the stented vessel several days after the angioplasty procedure. RESULTS: There was no correlation between urgency of the procedure, previous infarction, or previous coronary artery bypass grafting with successful procedure. The in-hospital mortality was 4.4%, 21% had a Q-wave myocardial infarction, and 1.5% sustained a stroke. Ejection fraction was the only correlate of long-term mortality. CONCLUSIONS: Coronary artery injury for which stents are placed for acute or threatened occlusion or to prevent restenosis but then fail, thus necessitating coronary artery bypass grafting, can be treated successfully. Although the rate of Q-wave myocardial infarction is substantial and related to the initial ischemic insult, the long-term survival and event rates are excellent with prompt surgical revascularization.

Aged↗
PubMed1995

[Detection of neck lymph node metastasis in the patients with supraglottic cancer].

Histo-pathologic materials from 115 cases of supraglottic squamous cell carcinoma were studied by retroSpective analysis. Each set of laryngeal specimens was reviewed with attention to the following factors: 1. Site of the primary lesion. 2. Size of the primary lesion. 3. Histologic grade of the primary tumor. 4. Histologic pattern at the tumor periphery. 5. Clinical and pathological stage. The features would reliably assist the laryngologist in identifying the laryngeal cancer with high probability of lymph node metastasis, so they can be used as the data for arranging the operation or treatment of the neck.

Adult↗
PubMed1995

[Detection of hypermethylation in affected males with fragile X syndrome by PCR assay].

PCR technique was applied to detect hypermethylation at BssH II recognition sites within CpG island of FMR-1 gene in normal, affected, and clinically suspected males with fragile X syndrome. Hypermethylation was found to occur in all 7 affected and 5 of 26 suspected, but none of 15 normal males. The results of PCR assay are in good coincidence with those of Southern blot and cytogenetic assays. This PCR assay will be a promising method in the diagnosis of fragile X syndrome in males with mental retardation.

Base Sequence↗
PubMed1995

[Studies on the transcription regulation by upstream sequence of human heat shock protein 90 beta gene].

Using a pair of synthetic oligonucleotide as primers, human peripheral lymphocyte lambda GEM-11 genomic DNA library as template, a fragment spanning -1102/+68bp of human heat shock protein 90 beta gene was amplified by polymerase chain reaction (PCR) and cloned into pGEM-4Z vector. The cloned fragment was truncated and ligated to an eukaryotic expression vector containing luciferase as a reporter gene. These subclones were transfected into Jurkat cells and the cellular luciferase activity and mRNA level were measured under either heat shock or PHA activation. Our results suggest that: (1) 5' flanking sequences of hsp90 beta mediates a relatively higher basal level expression via promotor region; (2) under heat shock, presence of the fragment surprisingly reduced luciferase activity, a heat shock induced negative regulatory element was restricted to -554/-171bp; and (3) PHA activation requires distal 5' sequence.

Base Sequence↗
PubMed1995

[Quantitative study of a SEM image processing system on the absorptive mesothelium of the diaphragmatic peritoneum].

SEM and a medical image processing system attached to SEM were used to study the peritoneal mesothelium on mice diaphragm. The absorptive mesothelium was first reported owing to its function and morphology. The absorptivity of diaphragmatic peritoneum was surveyed by the measurement of the area of the absorptive mesothelium. The arrangement of the absorptive mesothelium on diaphragmatic peritoneum was block-like with abnormal distribution, and the maximum and minimum areas of the block were 1153 microns 2 and 66 microns 2. But the absorptive mesothelium on left and right half diaphragm were normally distributed. The average areas of the absorptive mesothelium on all diaphragm, left half diaphragm and right half diaphragm were 432.6 microns 2, 270.5 microns 2 and 512.0 microns 2 respectively. The distributive law of the absorptive mesothelium was costal portion > sternum portion > vertebral column portion. The average absorptivity of all diaphragmatic peritoneum was 29.2%, but that of left and right half diaphragmatic peritoneum were 17.4% and 32.9% respectively.

Absorption↗
PubMed1995

[Structure and function of FMR].

The widespread basal expression of fragile X gene (FMR1) suggests that it is a house keeping gene, essential to the survival and function of the cells, but unrelated to proliferation and phenogenesis. The spatial temporal specific expression of FMR1 further suggests that it is an important development-regulating gene, essential to development, particularly to the development of CNS and reproductive system, and may play an important role in cell migration and differantiation. It may also be a posttranscription regulator, by binding to mRNA, regulates the posttranscription processing, transportation, translation and localization of mRNAs. The diversity of pathogenesis of Fra(X) individuals may be caused by the variation of the downstream genes regulated by FMR1.

Animals↗
PubMed1995

[Surveillance of levels of neutralizing antibodies against poliovirus among children aged 0-3 in rural areas of Anhui Province].

Levels of neutralizing antibodies against poliovirus (PV) in 1,755 children aged 0-3 sampled randomly from 18 counties in Anhui Province were determined in September, 1993. Results showed the positive rates and geometric mean titer (GMT) of neutralizing antibodies against PV type 1, 2 and 3 were 96.98%, 96.01% and 96.18%, and 524.80, 323.59 and 436.50, respectively. Immune level of children was considerable high in each county sampled. No significant difference was found among different age groups and between boys and girls in positive rates and GMT of polioantibodies, but there was significant difference in them between children administered varied doses of oral polio vaccine (OPV). Children investigated took four doses of OPV in average, and their GMT was in proportion to the dose they took. Positive rate of PV antibodies was more than 95% in children who finished the full course of OPV immunization. There were very few townships or villages with a low coverage of OPV immunization in children. It indicated polio immune status was in a higher level in the Province.

Antibodies, Viral↗