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Biomedical subjects

Y Shen

Publications and source records attributed to Y Shen.

At least 469 records · Page 26Linked to original sources
PubMed1995

[The cloning and expression of human secreted interleukin 2 receptor alpha chain gene in eukaryotic cells].

By deleting the sequences encoding the cytoplasmic domain, transmembrane domain and the 5' untranslated region, human interleukin-2 receptor alpha cDNA fragment was subcloned into an eukaryotic expression vector pRc/CMV. The recombinant plasmid was then transfected into CHO cells by either electroporation or calcium phosphate precipitation. 11 G418-resistent clones were randomly selected for detection of mRNA expression. 5 clones out of the 11 were proved to be positively hybridyzed with IL-2R alpha cDNA probe. All of the 5 positive cell lines also expressed sIL-2R alpha in their supernatants as detected by ELISA. The establishment of rhsIL-2R alpha cell lines is of importance in the detection and purification of IL-2 based on the ability of affinity binding between IL-2 and its recombinant receptor.

Animals↗
PubMed1995

[Photodynamic effect of HPD on DNA functions].

After treatment of the DNA by HPD and light the number of transformants of the M13mp8 DNA obviously decreased during the period of transforming the treated DNA into E coli. Meanwhile some of the mutation sequences appeared in the DNA which recovered from the DNA/HPD/Light transformant. It showed that the wrong replication happened because of the mutated template. Also the in vitro run-off transcription of IL-2R alpha gene was affected by HPD and light. It means that the DNA functions are influenced by the photodynamic effects.

Bacteriophage M13↗
PubMed1995

[Application of laparoscopic technique in splenic surgery].

Five patients of splenic operations had been performed by laparoscopic technique. Patients' ages ranged from 19 to 47, with an average of 31. Four were males and one was female. The procedures included splenectomy 1 patient, deroofing of splenic cyst (1), and hemostasis of splenic injuries (3). The results indicated that all the procedures were successful, and the average length of postoperative stay was 6.5 days. There were no complications. The advantages of laparoscopic splenic surgery include minimal incision, less postoperative pain and rapid recovery. It should be stressed, however, that laparoscopic splenic procedures should be performed cautiously for selected indications only and by surgical endoscopists well trained.

Adult↗
PubMed1995

[Detection of FMR-1 gene expression by RT-PCR].

Fragile X syndrome [FRA(X)] as the most common form of inherited mental retardation in man has an incidence of one per 1250 and is associated with a fragile site at Xq27.3. A gene was identified at the fragile X locus and was designated Fragile X Mental Retardation-1 (FMR-1). FRA(X) resulted from expansion of (CGG)n trinucleotide repeat in 5' untranslated region of the human FMR-1 gene, and was associated with abnormal methylation of a CpG island 250 bp proximal to this (CGG)n repeat. Males with typical FRA(X) showed repression of FMR-1 transcription and absence of FMR-1 protein, which was believed to contribute to the fragile X phenotype. FMR-1 mRNA extracted from leukocytes in normal and clinically suspected males were detected by RT-PCR. The methylation status and CGG expansion were also studied by PCR and Southern blot. Two of 10 clinically suspected males were found devoid of FMR-1 expression and accompanied with hypermethylation of the CpG island and CGG trinucleotide repeat expansion.

CpG Islands↗
PubMed1994

[Maximum-intensity-projection CT angiography for evaluating head and neck tumors: usefulness of helical CT and auto bone masking method].

Angiographic images of 10 adult patients with head and neck tumors were obtained by helical computed tomography (CT) using maximum intensity projection (MIP). In all cases, the vasculature of the head and neck region was clearly visualized, and hypervascular lesions were directly demonstrated. In the head and neck, bone masking is a more important problem than in other regions. We developed an effective automatic bone masking method (ABM) using 2D/3D connectivity. Helical CT angiography with MIP and ABM provided accurate anatomic depiction, and was considered to be helpful in preoperative evaluation of head and neck tumors.

Adult↗
PubMed1994

[Supplemental potassium or magnesium via the trachea with ultrasonic aerosol inhalation].

The common ways for supplementing potassium or magnesium have some disadvantages. Gaining enlightenment from endotracheal medication in cardiopulmonary resuscitation, the author tried to supplement potassium or magnesium via trachea with ultrasonic aerosol inhalation. Hypopotassemia and hypomagnesemia were induced in forty rabbits. Utilized orthogonal experiment design, serum potassium and magnesium level were compared with oral, intravenous, intratracheal and ultrasonic aerosol inhalation routes. Potassium chloride, normal saline, potassium magnesium aspartate, magnesium sulfate and potassium chloride plus magnesium sulfate were given respectively. Serum potassium and magnesium levels were markedly increased after ultrasonic aerosol inhalation drugs were given. There were no significant differences between oral or intravenous route and ultrasonic aerosol inhalation. The pathological results of trachea and lungs were normal.

Administration, Inhalation↗
PubMed1994

Relief of p53-mediated transcriptional repression by the adenovirus E1B 19-kDa protein or the cellular Bcl-2 protein.

The p53 tumor suppressor gene product is a transcriptional regulatory protein. It activates transcription from promoters that contain a p53 DNA binding site but represses many promoters that lack its binding site. High-level expression of wild-type p53 can induce apoptosis in certain cell types, and this activity can be blocked by the adenovirus E1B 19-kDa oncoprotein or by the cellular Bcl-2 oncoprotein. Here we report that p53-mediated repression of promoters that lack a p53 binding site is abrogated by the E1B 19-kDa protein or Bcl-2 oncoprotein. In contrast, transcriptional activation by p53 still occurs in the presence of either protein. The fact that two oncoproteins capable of preventing p53-mediated apoptosis also block transcriptional repression by p53 raises the possibility that p53 might induce apoptosis, at least in part, by repressing transcription.

Adenovirus E1B Proteins↗
PubMed1994

A PCR-based genetic linkage map of human chromosome 16.

A high-resolution cytogenetic-based physical map and a genetic linkage map of human chromosome 16 have been developed based on 79 PCR-typable genetic markers and 2 Southern-based RFLP markers. The PCR-based markers were previously characterized polymorphic (AC)n repeats. Two approaches have led to the characterization of 47 highly informative genetic markers spread along chromosome 16, some of which are closely linked to disease loci. In addition, 22 markers (D16S401-423) previously genetically mapped were also physically mapped. Ten markers characterized by other laboratories were physically mapped and genotyped on the CEPH families. These 32 markers were incorporated into the PCR-based map. Seventy-two markers have heterozygosities > 0.50 and 51 of these markers > 0.70. By multipoint linkage analysis a framework genetic map and a comprehensive genetic map were constructed. The length of the sex-averaged framework genetic map is 152.1 cM. The average distance and the median distance between markers on this map are 3.2 and 2.7 cM, respectively, and the largest gap is 15.9 cM. These maps were anchored to the high-resolution cytogenetic map (on average 1.5 Mb per interval). Together these integrated genetic and physical maps of human chromosome 16 provide the basis for the localization and ultimately the isolation of disease genes that map to this chromosome.

Animals↗
PubMed1994

Adaptor-based uracil DNA glycosylase cloning simplifies shotgun library construction for large-scale sequencing.

An improved strategy for the preparation of libraries for the random sequencing of DNA is reported. The protocol is a modification of a previous adaptor-based strategy, and utilizes long (11 base) overhangs, which eliminates the unreliable step of vector-insert ligation. The random inserts are prepared by adaptor ligation, while the M13 vector is prepared as described for uracil DNA glycosylase (UDG) cloning of polymerase chain reaction (PCR) products, using PCR with uracil-containing primers, followed by UDG treatment to produce overhangs. This method has been found to reliably yield large numbers of clones. There is no background due to religation of the vector, and all clones contain inserts. In addition, the method is simple and suitable for export to other investigators. Libraries were constructed from cosmids containing human DNA and from human cDNAs in order to characterize a strategy for shotgun sequencing of multiple shorter fragments.

Base Sequence↗
PubMed1994

Human transcription factor IIIC box B binding subunit.

Transcription factor IIIC (TFIIIC) is a multisubunit basic TF for RNA polymerase III. It initiates transcription complex assembly on tRNA and related genes by binding to the internal box B promoter element and is also required for transcription of 5S rRNA and other stable nuclear and cytoplasmic RNAs transcribed by polymerase III. In mammalian cells, regulation of TFIIIC activity controls overall polymerase III transcription in response to growth factors and viral infection. Here, we report the cloning and sequencing of a full-length cDNA (and genomic DNA from the transcription initiation region) encoding the box B binding subunit of human TFIIIC, the 243-kDa alpha subunit. Specific antisera raised against the encoded protein super shifts a TFIIIC-box B DNA complex during an electrophoretic mobility shift assay and immunodepletes TFIIIC transcriptional activity from a partially purified TFIIIC fraction, proving that the cDNA encodes a component of TFIIIC. The human protein shows surprisingly little similarity to the box B binding subunit of yeast TFIIIC.

Amino Acid Sequence↗
PubMed1994

Interaction of age and coronary disease after valve replacement: implications for valve selection.

The interaction of patient age and the presence of coronary artery disease (CAD) and its influence on survival were examined in 3,644 patients undergoing either aortic (AVR) or mitral (MVR) valve replacement with or without coronary artery bypass grafting (CABG) between 1974 and 1991. Emergency procedures were performed much more frequently in those undergoing MVR and CABG than in those undergoing AVR and CABG (18.8% and 6.7%, respectively). The adverse effect of CAD on median survival for patients of all ages undergoing either AVR or MVR was statistically significant (AVR without CAD 11.8 versus 8.7 years with CAD; MVR without CAD 12.7 versus 7.3 years with CAD; p < 0.0001). Survival in patients younger than 70 years without CABG who underwent either AVR or MVR was quite good (< 60 years: AVR, > 14 years; MVR, 15.4 years; 60 to 69 years: AVR, 10.4 years; MVR, 11.4 years). The most profound effect of CAD on patient survival after valve replacement was observed in patients 60 to 69 years of age who underwent MVR, in whom the median survival without CABG was 11.4 years versus 5.5 years with CABG (p < 0.0001). An emergency operative status was associated with a reduced early and late survival for those patients undergoing MVR, particularly those with CAD. By relating the Cox proportional hazard models for valve survival to patient survival, we found that, in those patients 70 years and older with and without CAD who underwent either AVR or MVR, the median patient survival was reduced sufficiently (5.5 versus 8.1 years) to justify use of a bioprosthetic valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1994

Identification and characterization of the gene causing type 1 spinocerebellar ataxia.

Spinocerebellar ataxia type 1 (SCA1) is a neurodegenerative disorder caused by expansion of a CAG trinucleotide repeat. In this study, we describe the identification and characterization of the gene harbouring this repeat. The SCA1 transcript is 10,660 bases and is transcribed from both the wild type and SCA1 alleles. The CAG repeat, coding for a polyglutamine tract, lies within the coding region. The gene spans 450 kb of genomic DNA and is organized in nine exons. The first seven fall in the 5' untranslated region and the last two contain the coding region, and a 7,277 basepairs 3' untranslated region. The first four non-coding exons undergo alternative splicing in several tissues. These features suggest that the transcriptional and translational regulation of ataxin-1, the SCA1 encoded protein, may be complex.

Alternative Splicing↗
PubMed1994

Effects of heat stress on Na+,K(+)-ATPase, Mg(2+)-activated ATPase, and Na(+)-ATPase activities of broiler chickens vital organs.

Na+,K(+)-ATPase, Mg(2+)-activated ATPase, and Na(+)-ATPase activities of brain, heart, kidney, and small and large intestinal mucosa of broiler chickens exposed to heat stress (41 degrees C, 65% relative humidity for 6 h) and thermoneutral (25 degrees C, 65% relative humidity) conditions were determined. Brain and kidneys were found to have significantly higher Na+,K(+)-ATPase activities than those of heart and intestinal mucosa. Mg(2+)-activated ATPase and Na(+)-ATPase activities in the intestinal mucosa were higher than those of brain, kidneys, and heart under thermoneutral conditions. While there was a significant inhibition of total ATPase, Na+,K(+)-ATPase, Mg(2+)-activated ATPase, and Na(+)-ATPase activity of small and large intestinal mucosa of broiler chickens exposed to heat stress, the inhibitory effect was limited to total ATPase and Na+,K(+)-ATPase enzymes in kidneys. Heat stress produced a significant increase only in Mg(2+)-activated ATPase activity of the heart, without a remarkable change in all forms of ATPase activity in the brain. Heat stress significantly decreased the ratio of Na+,K(+)-ATPase to Mg(2+)-ATPase in the heart, kidneys, and small and large intestinal mucosa. The percentage of Na(+)-ATPase in Na+,K(+)-ATPase of brain, heart, and kidneys did not significantly change during heat stress, but the ratio in small and large intestinal mucosa increased significantly during heat stress. The severe disturbances in both serum electrolytes and acid-base balance observed in previous heat stress studies could partly be mediated by direct or indirect effects of heat stress on Na+,K(+)-ATPase, Mg(2+)-activated ATPase, and Na(+)-ATPase activities of kidneys, and small and large intestinal mucosa of broiler chickens.

Adenosine Triphosphatases↗