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Biomedical subjects

Z Yin

Publications and source records attributed to Z Yin.

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

Multiple signalling pathways trigger the exquisite sensitivity of yeast gluconeogenic mRNAs to glucose.

The transcription of the yeast FBP1 and PCK1 genes, which encode the gluconeogenic enzymes fructose-1,6-bisphosphatase and phosphoenolpyruvate carboxykinase, is repressed by glucose. Here, we show that this repression is both very strong and exceptionally sensitive to glucose, being triggered by glucose at concentrations less than 0.005% (0.27 mM). This repression remains operative in yeast mutants carrying any one of the three hexose kinases, but is lost in a triple hxk1, hxk2, glk1 mutant. In addition, 2-deoxyglucose can trigger the repression, but 6-deoxyglucose cannot, suggesting that internalization and phosphorylation of the glucose is essential for repression to occur. While gluconeogenic gene transcription is subject to the Mig 1p-dependent pathway of glucose repression, the exquisite response to glucose is maintained in hxk2 and mig1 mutants, suggesting that this pathway is not essential for the response. The response can also be triggered by the addition of exogenous cAMP, suggesting that the Ras/cAMP pathway can mediate repression of the FPB1 and PCK1 mRNAs. However, the response is not dependent upon this pathway because it remains intact in Ras, adenyl cyclase and protein kinase A mutants. The data show that yeast cells can detect very low glucose concentrations in the environment, and suggest that several distinct signalling pathways operate to repress FPB1 and PCK1 transcription in the presence of glucose.

Cell Cycle Proteins↗
PubMed1996

Risk factors for substance use by Mexican American youth with and without learning disabilities.

This survey study was designed to (a) investigate the prevalence of minor and major substance use among low socioeconomic status elementary and middle school Mexican American students identified with learning disabilities (LD; n = 150) and without LD (n = 150), and (b) identify psychosocial and environmental risk factors that may lead to the use of various substances among both non-learning disabled (non-LD) students and students with LD in an all-Mexican American sample. No differences were found in the use of substances between the two groups. Risk factors that were found to influence the use of minor substances for students identified as learning disabled, as opposed to the non-LD students, included use of substances by close friends and susceptibility to peer influence. Risk factors that were found to affect the use of major substances for students identified as learning disabled, as opposed to the non-LD students, included the number of minor substances used and stressful life events. Findings are discussed in the context of differing pathways leading to the use of substances for non-LD students and students with LD within an intraethnic group study.

Adolescent↗
PubMed1996

Cognitive-affective sources of sport enjoyment in adolescent sport participants.

Cognitive-affective sources of sport enjoyment were examined among male high school freshmen (N = 231), all of whom had participated in organized youth sport. Subjects completed several sport-specific measures. Also, recorded was an indicator of number of years of participation in organized sport. Stepwise multiple regression analysis indicated that significant sources of sport enjoyment included task orientation, perceived competence, learned helpless affect, and years of participation in organized sport. Results also indicated, however, that ego orientation failed to enter the stepwise equation as a significant predictor of sport enjoyment. The findings are discussed in regard to the importance of the development of competence to enjoyment. Suggestions are offered for the need to advance task orientation and self-referenced perceived ability in sport achievement settings in order to foster positive affect and ongoing participation in organized youth sport.

Adolescent↗
PubMed1996

[Sequence analysis of the cytochrome b gene fragment in a dinosaur egg].

A 170bp PCR products was amplified the DNA in a dinosaur egg using primers designed from the conserved regions of human cytochrome b gene and was sequenced. BLAST search through INTERNET for homology detection showed that the sequence was almose identical with the human mitochondria cytochrome b gene(96-100% similarity). Therefore we can conclude that the dinosaur egg itself has been seriously contaminated.

Animals↗
PubMed1996

Characterization of pathogenic fungi genomes using pulsed field gel electrophoresis.

Pulsed field gel electrophoresis (PFGE) has been firstly introduced in characterization of the pathogenic fungi Penicillium marneffei and Exophiala dermatitidis genomes. The numbers and sizes of their chromosomes have been detected. Polymorphism was identified on the smallest chromosome of E. dermatitidis. The result shows that PFGE for characterization of large molecular DNA pathogenic fungi is very suitable, it is more simple and more efficacy. The result also shows the diversity of pathogenic fungi is relative common even in rare occurred pathogenic fungi such as E. dermatitidis.

DNA, Fungal↗
PubMed1995

[Study on the calibration model of electronystagmography (ENG) in the guinea pigs].

The passive calibration of ENG according to the gain of OKN evoked in guinea pigs was studied in this paper. The method was also verified by animal experiment and the comparison between active calibration and passive one in normal subjects. OKN was elicited by optokinetic drum with black and white strips at 10 intervals at velocity of 5-60 degrees/s. The calculating formula of passive calibration in animals obtained by mathematical corollary is K = G . ST sigma . DV/SA sigma. The slow-phase velocity of spontaneous nystagmus in a group of animals with acute loss of unilateral vestibular function recorded with this method showed typically a logarithmic decline within 24 hours. No significant difference between the values of active and passive calibration was found in normal subjects. The results demonstrated that the method described in the paper was accurate and reliable. It can be used in perivestibular experiments.

Animals↗
PubMed1995

[Transsphenoidal microsurgical removal of GH-secreting pituitary adenoma in: a report of 200 cases].

From July 1979 to April 1992, 212 cases of GH-secreting pituitary adenoma were treated transsphenoidally by microsurgical technique, of whom two hundred cases monitored with their GH levels at preoperative and postoperative periods. The majority of cases totally 132 cases were of macroadenoma, and 68 cases were of microadenoma. 138 cases were operated on after April 1986. The cure and remission rate averaged to 72.5%, rising from 44.4% (before 1986) to 80.5% for microadenoma and from 31.4% to 69.1% for macroadenoma due to improvement of technique and accumulation of experience. One patient died of angiocardiopathy suddenly during operation. Mortality rate was 0.5%. The follow-up observation of postoperative GH levels in 52 cases revealed that the GH levels within 2 weeks after operation were the same as in 3-6 months. It is thought that the early GH levels may represent the surgical results. The surgical technique is described and factors influencing the surgical results, prevention and treatment of operative complications are discussed in this paper.

Adenoma, Acidophil↗
PubMed1995

[Expression and regulation of milk protein gene in mammalia].

On the basis of introducing the structures and relations of evolution in milk protein genes, the factors involved in gene expression including cis-acting elements, trans-acting factors as well as induction of hormones were discussed. Finally the applicable prospect of mammary gland as a bioreactor was estimated.

Animals↗
PubMed1994

Sensitivity of 3T3 cells to low serum concentration and the associated problems of serum withdrawal.

The sensitivity of cells to serum deprivation depends upon whether they are transformed. Most supplies of 3T3 cells are of this type and are considerably less sensitive than untransformed cells. In addition, the apparently simple manoeuvre of reducing serum levels has considerable effects on cell fragility, viability, growth rate and metabolism, which were found to be due to small changes in pH, substrate availability, cell density and other parameters, many of which cannot be attributed to the absence of growth factors from the medium. Supplementation of medium with bovine serum albumin (BSA) to compensate for low normal serum protein did not aid growth nor offset the disturbances caused by low serum levels themselves. Problems associated with the altered precursor availability for DNA, RNA and protein synthesis are also discussed.

3T3 Cells↗
PubMed1994

Phenotypic heterogeneity of persistent expansions of CD4+ CD8+ T cells.

A group of 18 individuals is described that manifest persistent (follow up between 4 and 57 months) expansions (ranging from 10 to 70%) of CD4+ CD8+ peripheral T cells. In nine individuals there was no apparent underlying disease whereas the remaining displayed a wide range of unrelated diseases. Analysis of the cell surface immunophenotype showed that all individuals express high densities of CD2, CD3, CD5, and TCR alpha/beta on their CD4+ CD8+ subset. On the contrary, these cells did not express CD25, CD38, CD71, HLA-DR, and the beta chain of the interleukin-2 receptor (p75) but expressed high density of CD29 and low density or absence of CD7. CD8 was "dim" in most individuals and consisted only of the CD8 alpha chain isoform. These individuals could be further divided into two subgroups based on the following parameters: in eleven cases CD4+ CD8+ cells had an LGL morphology and expressed the CD11b, CD56 and CD57 NK-associated antigens; in addition, a high percentage of CD4+ CD8- cells from the same individuals also expressed NK-associated antigens on their cell surface (subgroup A). The CD4+ CD8+ cells of the remaining individuals had small lymphocyte morphology, expressed little or no CD11b and CD56 and their CD4+ CD8- cells did not express NK-associated antigens at all (subgroup B). Finally, CD8 was "bright" on the CD4+ CD8+ cells of three individuals and in these cells also the CD8 beta chain isoform was present (subgroup C). Southern blot hybridization of genomic DNA with a T-cell receptor beta probe revealed that of the sixteen individuals examined four had a monoclonal, seven an oligoclonal, and five a polyclonal molecular configuration. The present data indicate that persistent CD4+ CD8+ expansions represent a novel heterogeneous subset of T cells.

Adult↗
PubMed1994

Evaluation of laboratory methods for cystic fibrosis carrier screening: reliability, sensitivity, specificity, and costs.

We report a comparative evaluation of three different laboratory methods for screening large numbers of mouthwash DNA samples for common cystic fibrosis mutations. Sensitivity, specificity, and costs of ARMS (allele refractory mutation detection system), dot blotting, and a deletion/digest/PAGE method (multiplex PCR of exons 10 and 11, digest with HincII followed by polyacrylamide gel electrophoresis (PAGE)) were assessed. ARMS was the most reliable and sensitive method and so was considered more suitable than the cheaper deletion/digest/PAGE. As well as being less reliable than ARMS, the dot blotting method assessed was considerably more costly. ARMS was the best laboratory method for CF screening tested.

Cystic Fibrosis↗
PubMed1994

Serum deprivation and the turnover of short-, medium- and long-lived proteins in 3T3 and HeLa S-3 cells.

Protein turnover in serum-deprived Swiss 3T3(U) untransformed and 3T3(T) transformed cells was comprehensively studied. When 3T3(U) cells were cultured in 0.2% serum medium, protein synthesis fell to 28% of the control value by 48 h, but took at least 12 h to become manifest. Meanwhile the rates of degradation of medium- and long-lived proteins were increasing, with a 1.65-fold increase in degradation of the former within 2 h, and the turnover of long-lived proteins doubling in 24 h. A significant increase in the degradation of truly short-lived proteins was not apparent until 24 h of deprivation. After serum restoration in cultures deprived of serum for 24 h, protein synthesis increased from 25 to 40% of the control values within 1 h, reaching 93% by 24 h. The rate of medium-lived protein degradation in 3T3(U) cells quickly returned to control levels, and that of long-lived proteins fell to less than control levels by 3 h, decreasing to 67% by 24 h. This contrasted with short-lived protein turnover, which remained at the same level as the cells kept in 0.2% serum for a further 24 h. The turnover of medium- and long-lived proteins is initially more important than short-lived proteins in growth regulation following the removal of growth factors.

3T3 Cells↗
PubMed1994

Primary cilia in cultured mammalian cells: detection with an antibody against detyrosinated alpha-tubulin (ID5) and by electron microscopy.

A fluorescent-labelled antibody against detyrosinated alpha-tubulin, ID5 (Wehland and Weber, 1987), allows primary cilia and centrioles to be detected rapidly and accurately for analysis in cell cultures. Many features of primary cilia have been re-examined, including frequency of expression in relation to levels of confluency, different sera, different cell cycle stages, and following trypsinization and centrifugation procedures. The detection of multiple ciliation per cell, and the precise positioning of cilia in cells in monolayers are readily recorded. The findings are discussed in relation to cilium expression in cell growth and cycling, to previous findings based on ultrastructural analysis, and to their potential role in sensing the local environment.

3T3 Cells↗
PubMed1993

[Nucleotide sequence and genome structure of mink enteritis virus].

This paper reports the sequence of the cloned mink enteritis virus (MEV) RF DNA and its 3' end and 5' end structure predicted. MEV genome is near 5064 nucleotides (nt) in length. In its 5' end non-coding region, there are three 51 nt repeated sequences. The nucleotide sequence of MEV genome has very high homology with those of canine parvovirus (CPV) and feline parvovirus (FPV), reaching 99.1% and 99.9% respectively in the structure gene region. But they differ notably in 5' end non-coding region. The structure of MEV genome is almost same as those of CPV and FPV. It has two large open reading frames which code for 668 and 722 amino acids respectively. There are two promoters at map unit 37 and 39. At map unit 97, there is a poly A site. All the mRNAs of NS2, VP1 and VP2 are spliced.

Animals↗
PubMed1992

Prospective study on the diagnosis of hepatocellular carcinoma by using alpha-fetoprotein reactive to lentil lectin.

In order to study the changes in AFP reactive to lentil lectin (AFP-R-L) during the development of hepatocellular carcinoma (HCC) and its clinical significance, AFP-R-L was monitored in 64 patients by using 20-400 ng/L AFP and negative imaging localization. AFP-R-L was determined by using affino-crossed-immunoelectrophoresis autoradiography. AFP-R-L above 25% was considered positive for the diagnosis of HCC. Over a follow-up of 3-31 months, 32 patients developed HCC. The positivity of AFP-R-L was 59.4% in the HCC group at the first assay. The accuracy of using positive AFP-R-L values to predict HCC was 95.0%. Increased AFP-R-L levels appeared 3-24 months earlier than did positive imaging location. The results suggest that positive AFP-R-L values can predict the development of HCC.

Adenosine Triphosphate↗