Solid-solid interface and solid solution of oxides with rock-salt structure: Lattice properties.
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Journal Article↗
Biomedical subjects
Q Shen
Publications and source records attributed to Q Shen.
Functional dissection of an abscisic acid (ABA)-inducible gene reveals two independent ABA-responsive complexes each containing a G-box and a novel cis-acting element.
To elucidate the mechanism by which abscisic acid (ABA) regulates gene expression, the promoter of the barley ABA-responsive HVA22 gene has been analyzed by both loss- and gain-of-function studies. Previous reports indicate that G-box sequences, which are present in genes responding to a variety of environmental and physiological cues, are involved in ABA response. However, our data suggest that G-box sequences are necessary but not sufficient for ABA response. Instead, an ABA response complex consisting of a G-box, namely, ABRE3 (GCCACGTACA), and a novel coupling element, CE1 (TGCCACCGG), is sufficient for high-level ABA induction, and replacement of either of these sequences abolishes ABA responsiveness. We suggest that the interaction between G-box sequences, such as ABRE3 in the HVA22 gene, and CE-type sequences determines the specificity in ABA-regulated gene expression. Our results also demonstrate that the ABA response complex is the minimal promoter unit governing high-level ABA induction; four copies of this 49-bp-long complex linked to a minimal promoter can confer more than 100-fold ABA-induced gene expression. In addition to ABA response complex 1, composed of ABRE3 and CE1, the HVA22 promoter contains another ABA response complex. The ABA responsiveness of this ABA response complex 2 relies on the interaction of G-box (ABRE2; CGCACGTGTC) with another yet unidentified coupling element. These two complexes contribute incrementally to the expression level of HVA22 in response to ABA.
Abscisic Acid↗
Efficient and specific induction of esophageal tumors in rats by precursors of N-nitrososarcosine ethyl ester.
Cancers and precancerous lesions of the esophagus were efficiently induced in rats by the simulation of a clinico-epidemiological setting; that is, the administration of precursors of nitrosamine. Six week old non-inbred male Wistar rats were given 2g/kg bodyweight of sarcosine ethyl ester hydrochloride (SEEH) and concurrently 0.3g/kg bodyweight of sodium nitrite (NaNO2), precursors of N-nitrososarcosine ethyl ester (NSEE), in 2% sucrose as drinking water. Group 1 received the precursors twice a week for 6 weeks followed by 8 weeks observation, and group 2, once every 3 days for 7 weeks followed by 26 weeks observation. At the end of treatment, no tumor had developed in the esophagus of rats in group 1, but the [3H]-thymidine labeling indices in both basal and superficial layer cells were higher than in the control group. On subsequent observation, papillomas appeared in group 1 (33.3%), and carcinomas in group 2 (33.3%), within 4 weeks. The tumors induced in group 1 were mostly papillomas and rarely carcinomas. When the observation was prolonged in group 2, 100% of the animals had cancer in week 20. The pathological changes of the lesions paralleled the sequential development of human squamous cell carcinoma of the esophagus. Our system has the advantages in that papillomas and cancers can be induced in rats in a short time and the agents used are less toxic than preformed nitrosamines administered previously by gastric intubation. It would serve as a useful experimental tool to study premalignant lesions and cancers of the esophagus.
Animals↗
Structure and function of the selenium translation element in the 3'-untranslated region of human cellular glutathione peroxidase mRNA.
In eukaryotes, incorporation of selenocysteine into the polypeptide chain at a UGA codon requires a unique sequence motif, or "selenium translation element" (STE), located in the 3'-untranslated region of the mRNA. The present study examines structure-function relationships of conserved sequence elements and of the putative stem-loop secondary structure in the STE of human GPX1 mRNA, which encodes the important antioxidant enzyme cellular glutathione peroxidase (EC 1.11.1.9). Deletion of the basal stem, upper stem, or apical loop of the stem-loop structure eliminated the ability of the STE to direct selenocysteine incorporation at the UGA codon of an epitope-tagged GPX1 reporter construct transfected into COS1 cells. However, mutations that change the primary nucleotide sequence of nonconserved portions of the stem-loop, but preserve its overall secondary structure, by inversion of apical loop sequences or exchange of 5' and 3' sides of stem segments, had little or no effect on selenocysteine incorporation. Effects of single- and double-nucleotide substitutions in three short, highly conserved elements in the GPX1 STE depended in large part on their computer-predicted perturbation of the stem-loop and its midstem bulge. Only in the conserved "AAA" apical loop sequence did mutations show major effects on function without predicted changes in secondary structure. Our results demonstrate the critical role of the three short, highly conserved sequences. However, outside of these elements, the function of the human GPX1 STE appears to depend strongly on the stem-loop secondary structure.
Animals↗
Osteomyelitis of sacral spine caused by aspergillus versicolor with neurologic deficits.
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Adult↗
[A study on effect of qingwen granule in regulating immunological function in infantile respiratory viral infection].
To evaluate the effect of Qing-wen Granule (QWG) on immunological function, T lymphocyte subsets and interferon gamma(INF-gamma) expression cells in peripheral blood mononuclear cells, lymphocyte transformation rate and the level of salivary secretory IgA (sIgA) were determined by alkaline phosphatase antialkaline phosphatase (APAAP) technique or 3H-TdR incorporation with lymphocyte stimulation index(SI) or agar single immunodiffusion in infantile respiratory viral infection. The results showed that the percentage of CD3, CD4, and CD4/CD8 ratio of patients treated with QWG for 3 days were not significantly different in comparing with the control group untreated with QWG (P > 0.05), but the values of IFN-gamma expression cell, SI and the level of sIgA were more markedly increased than that of control (P < 0.05). It suggested that the QWG could improve and regulate immune function in infantile respiratory viral infection.
Adjuvants, Immunologic↗
High prevalence of p53 protein overexpression in patients with esophageal cancer in Linxian, China and its relationship to progression and prognosis.
BACKGROUND: Linxian is the highest endemic area of esophageal squamous cell carcinoma (ESCC) in China and one of the highest incidence areas in the world. The relationship of p53 protein accumulation to geographic variation, pathologic findings, and prognosis has not been investigated extensively. METHODS: Formalin fixed, paraffin embedded ESCC tissues from 100 patients who underwent esophagectomy between 1973 and 1983 were immunostained by using monoclonal antibody pAB1801. RESULTS: p53 overexpression was observed in 41 (87.2%) of 47 tumors of patients in Linxian and in 16 (64%) of 25 additional patients outside Linxian. Its prevalence in the noncancerous epithelium (11/72, 15.3%) and carcinoma in situ (1/7, 14.3%) was lower than that in invasive lesions (64/93, 68.8%). Its immunostaining intensity increased with the depth of cancer invasion. Of 30 primary carcinomas with lymph node metastasis, 29 (96.7%) were positive. However, only 36 (51.4%) of 70 primary lesions without metastasis were positive, and a higher intensity was noticed in the metastases. There was a lower expression rate in tumors of patients surviving more than 10 years (25/52, 48.1%) than in those surviving less than 3 years (40/48, 83.3%). Overall and nonadvanced or metastasis-free cumulative survival rates were both significantly different in patients with and without p53 protein overexpression. CONCLUSIONS: There is a higher expression rate of p53 protein in ESCC in tumors of patients from Linxian than in those from the surrounding area. The accumulation of p53 protein is related to the invasiveness and capability for metastases of cancer cells and appears to be a useful prognostic factor for patients with ESCC.
Adult↗
Chronic granulomatous disease and glutathione peroxidase deficiency, revisited.
We have restudied two kindreds that formed the basis of the original report of autosomal recessive chronic granulomatous disease (CGD) associated with leukocyte glutathione peroxidase deficiency. Case 1 from the original study and the surviving brother of the originally reported case 2 both have severe CGD, with no detectable respiratory burst activity in purified intact neutrophils. However, their leukocytes exhibit normal glutathione peroxidase enzyme activity and gene expression. Examination of phagocyte nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase components known to be defective in CGD reveals no detectable cytochrome b558 nor any membrane activity in a cell-free NADPH oxidase assay system. Molecular analysis of the genes encoding cytochrome b558 subunits shows, in case 1, a C-->T substitution at nucleotide 688 of the gene encoding the gp91-phox subunit of cytochrome b558, resulting in a termination signal in place of Arginine-226. Levels of gp91-phox mRNA are markedly decreased despite normal levels of gene transcription, indicating a post-transcriptional effect of the nonsense mutation on mRNA processing or stability. The X-linked form of CGD developed in this cytogenetically normal female due to the uniform inactivation of the normal X chromosome in her granulocytes, indicated by the expression in her granulocyte mRNA of only one allele of a glucose-6-phosphate dehydrogenase polymorphisms for which she is heterozygous in genomic DNA. Case 2 (of the present study) has distinct mutations in each allele of the p22-phox gene.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Regulation of the human cellular glutathione peroxidase gene during in vitro myeloid and monocytic differentiation.
We have used the HL-60 and PLB-985 myeloid leukemia cell lines to examine the regulation of expression of the important intracellular antioxidant enzyme, glutathione peroxidase (GSH-Px), during phagocytic cell differentiation in vitro. Induction of differentiation along the monocytic pathway by phorbol ester results in an approximately twofold rise in enzyme activity and a parallel increase in the rate of 75Se incorporation into immunoprecipitable GSH-Px protein. Induction along the granulocytic pathway by dimethyl formamide (DMF) results in similar changes in steady-state enzyme levels and rates of GSH-Px protein synthesis. Steady-state levels of GSH-Px gene transcripts also increase more than twofold, approximately in parallel with the enzyme levels. Nuclear run-on transcription assays of GSH-Px mRNA synthesis show ratios of induced to uninduced transcript levels of 2.24 and 1.59 with phorbol myristate acetate (PMA) induction and DMF, respectively, in HL-60 cells, and ratios of 1.34 and 3.46 with PMA and DMF, respectively, in PLB-985 cells. Half lives of GSH-Px mRNA are unchanged or slightly shorter after differentiation of HL-60 cells, and slightly longer after induction of PLB-985. Overall, the present studies show that GSH-Px activity rises during in vitro-induced monocytic or granulocytic differentiation of myeloid cell lines and that the increased expression of the cellular GSH-Px gene occurs through complex mechanisms that include transcriptional up-regulation. This pattern contrasts with the nearly complete cotranslational regulation of GSH-Px expression by exogenous selenium.
Cell Differentiation↗
Search for hidden charm states decaying into J/ psi or psi ' plus pions.
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Journal Article↗
An in-frame trinucleotide repeat in the coding region of the human cellular glutathione peroxidase (GPX1) gene: in vivo polymorphism and in vitro instability.
We report the variation in vivo and instability in vitro of an in-frame GCG trinucleotide repeat in the human cellular glutathione peroxidase (GPX1) gene. In a population study of 110 alleles from 55 unrelated individuals, the allele frequencies for 4, 5, and 6 GCG repeats were 0.40, 0.35, and 0.25, respectively. No allele was associated with diminished enzyme activity. Current stocks of HL-60 cells, a human myeloid leukemia cell line, are homozygous for the 6-repeat allele. Early passage HL-60 cells frozen in 1976 show a 4/6 genotype and "intermediate" passage cells frozen in 1985 contain both 4/6 and 5/6 genotypes. Thus, the expansion of the repeat appears to have developed in the course of multiple passages of the rapidly proliferating cell line.
Alleles↗
Esophageal balloon cytology and subsequent risk of esophageal and gastric-cardia cancer in a high-risk Chinese population.
Linxian, China has some of the highest rates of esophageal/gastric cardia cancer in the world. In 1983, esophageal balloon cytology screening was performed in 3 communes in northern Linxian. Of the participants, 10,066 with no evidence of cancer were followed prospectively for 7 1/2 years to evaluate the ability of the initial cytologic diagnoses to identify individuals at increased risk for developing cancer of the esophagus or gastric cardia. A total of 747 incident cases of esophageal or cardia cancer and 322 deaths due to these tumors were identified during the follow-up period and used in this analysis. The risks for esophageal or cardia cancer incidence and mortality increased in parallel with the presumed severity of the 1983 Chinese cytologic diagnoses. After adjusting for potential confounding factors, relative risks for esophageal or cardia cancer incidence, by initial cytologic diagnosis, were normal = 1.00 (reference), hyperplasia = 1.25, dysplasia 1 = 2.20, dysplasia 2 = 4.22 and near-cancer = 5.96. Our results suggest that esophageal balloon cytology, as performed and interpreted in Linxian in 1983, successfully identified individuals at increased risk for developing cancer of the esophagus or gastric cardia.
Age Factors↗
Isolation of complementary DNA encoding K-cadherin, a novel rat cadherin preferentially expressed in fetal kidney and kidney carcinoma.
Complementary DNA for a novel member of the cadherin family, designated K-cadherin, was isolated from a rat renal cell carcinoma complementary DNA library by screening it with a short complementary DNA probe which was initially obtained from the RNA of day 16 fetal Wistar rat stomach mucosa by the polymerase chain reaction. The deduced primary structure of K-cadherin is 789 amino acid residues, which contain five internal repeats in its extracellular domain, a single putative transmembrane domain, and a cytoplasmic tail characteristic of those of classic type cadherins. K-cadherin exhibits low homology with mature proteins of mouse N- (38%), E- (35%), and P-cadherin (32%), and high homology with a partially identified human cadherin-6 protein (95%) at the amino acid level. Northern blot analysis revealed a high level of expression of K-cadherin mRNA in fetal rat kidney and brain, and rat kidney carcinoma with two major transcripts, 4.1 and 8.0 kilobases in size, whereas there was very weak or no expression in any organ of adult rats. The level of K-cadherin expression was also elevated in some human kidney cancer tissues. In the developing kidney, in situ hybridization showed localization of K-cadherin mRNA in the nephroblastic epithelial cells of comma bodies coinciding with those in the process of polarization during glomeruloneogenesis. These results demonstrate that K-cadherin must have important functions in both the process of kidney development and tumorigenesis of some types of kidney cancer.
Amino Acid Sequence↗
Esophageal morphology from Linxian, China. Squamous histologic findings in 754 patients.
BACKGROUND: Linxian, China, has one of the highest rates of esophageal cancer in the world. Other authors have described high prevalences of histologic esophagitis, atrophy, and dysplasia in Linxian and have suggested that these findings may represent precancerous lesions in this population. In 1987, a new endoscopic survey allowed the authors to make an independent study of esophageal histology in Linxian. METHODS: There were 1567 satisfactory squamous esophageal biopsies available from 754 patients. These biopsies were classified as normal, atrophy, acanthosis, esophagitis, squamous dysplasia, or squamous cancer. RESULTS: Classified by their worst diagnosis, 56.5% of the 754 patients had normal mucosa, 0.0% atrophy, 11.5% acanthosis, 4.6% esophagitis, 22.7% squamous dysplasia, and 4.6% squamous cancer. CONCLUSIONS: The results show a different distribution of esophageal squamous diagnoses than has been reported previously from this population. The authors believe that the major reason for this discrepancy was differences in histologic criteria. In this survey, seemingly small differences in criteria could cause large differences in apparent disease prevalence; this was especially true for esophagitis. By the criteria used in this study, histologic esophagitis and atrophy are uncommon findings in Linxian, raising questions about their significance as precursor lesions of esophageal cancer in this population.
Biopsy↗
The effect of vitamin and mineral supplementation on esophageal cytology: results from the Linxian Dysplasia Trial.
The population of Linxian in China has one of the world's highest rates for esophageal/gastric cardia cancer, as well as documented nutritional deficiencies. To determine whether dietary supplementation with a multi-vitamin multi-mineral preparation could reduce the risk of esophageal cancer and favorably influence precursor lesions, 3,318 individuals age 40-69 with cytologically determined grade 1 or grade 2 esophageal dysplasia were randomly assigned to receive either an active multi-vitamin multi-mineral supplement or a placebo. Pills were distributed at monthly visits and incident cancers or deaths were recorded. At 30 and 72 months subsequent to randomization all living participants without a known incident cancer were asked to undergo repeat cytological examination of their esophagus. Based on these procedures participants were classified as having no dysplasia, dysplasia grade 1, dysplasia grade 2 or near cancer dysplasia. Diagnoses of cancer were based on the cytology findings plus available histologic, radiologic and clinical materials. At the end of the study there was little overall difference in cumulative risk of esophageal cancer between those receiving vitamin/mineral supplementation and those receiving placebo. There was, however, a significant increase in reversion to non-dysplastic cytology among the group receiving the active treatment. The odds of not having any dysplasia at the two post-randomization screens was 1.23 times higher in the active treatment group than in the placebo group. Within each treatment group higher categories of dysplasia were associated with higher rates of cancer.
Adult↗
Production of chi charmonium via 300-GeV/c pion and proton interactions on a lithium target.
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Journal Article↗
Structure and promoter analysis of an ABA- and stress-regulated barley gene, HVA1.
A single-copy barley gene, HVA1, encoding a class 3 late embryogenesis-abundant protein, can be induced by either treatment with abscisic acid (ABA) or by stress conditions such as drought, cold, heat and salinity. We have isolated an HVA1 genomic clone containing about 400 bp of 5'-upstream sequence, a single 109 bp intron, and the full coding sequence. Linker scan mutagenesis and transient expression studies were used to test the function of four HVA1 promoter elements conserved in ABA-responsive genes. Mutations in two of these elements, the C box and the putative ABRE 1 (ABA-responsive element) containing an ACGT core, resulted in no significant change in transcription level or ABA induction. In contrast, mutations of the other two elements, putative ABRE 2 & 3 cause the level of transcription to drop to 10-20% of that obtained with the wild-type promoter indicating that the high level of expression of HVA1 is dependent on both pABRE 2 & 3. Interestingly, despite their low level of expression, the mutated promoters still gave more than 20-fold induction in response to ABA treatment. We suggest that the ABA induction of barley HVA1 gene is governed by a complex consisting of pABRE 2 & 3 working together to regulate the absolute level of expression, and either of these elements or a possible third element may regulate ABA inducibility. Phylogenetic analysis by parsimony indicates that the barley HVA1 and wheat pMA2005 sequences share a recent common ancester. These two genes are closely related to the carrot Dc3 and cotton D-7 genes with which they share a similar structural gene organization.
Abscisic Acid↗
Blood pressure changes and hormonal contraceptives.
The effects of low-estrogen and progestogen-only contraceptives on blood pressure changes were investigated on 238 women taking 35 micrograms EE OC, 267 using Norplant implants and 259 adopting IUD. The mean increases in diastolic pressure at 12, 24, 36 and 48 weeks among pill users were significantly (p < 0.05) higher than those among IUD users by 1.8, 2.1, 2.3 and 1.9 mm Hg, respectively; the increases in systolic pressure were higher but not significant (p > 0.05) by 1.3, 1.7, 1.5 and 1.3 mm Hg. Neither systolic nor diastolic blood pressure was affected by use of Norplant implants. Regression analysis, including interaction terms, showed that women's age, obesity and family history of hypertension were associated with an increase of blood pressure during follow-up and were independent of contraceptive use and vice versa. After adjustment of some potential confounding variables, pill users showed a 1.0 mm Hg rise in diastolic pressure, which is statistically significant but clinically unimportant.
Adult↗