Relationship between CD44v6 expression and metastatic potential and prognosis in gastric carcinoma.
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Antigens, Neoplasm↗
Biomedical subjects
X Yan
Publications and source records attributed to X Yan.
[Advances in the study of active constituents to cardiovascular system in alkaloids of medicinal plants].
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Alkaloids↗
Characteristics of different nucleic acid staining dyes for DNA fragment sizing by flow cytometry.
An efficient and reliable double-stranded DNA (dsDNA) staining protocol for DNA fragment sizing by flow cytometry is presented. The protocol employs 0.8 microM of PicoGreen to label a wide range of DNA concentrations (0.5 ng/mL to 10,000 ng/mL) without regard to the solution dye/bp ratios and without initial quantification of the DNA analyte concentration. Using a combination of spectrofluorometry and flow cytometry experiments, we found that PicoGreen exhibited better overall performance than all the tested dsDNA binding dyes, such as TOTO-1. Fluorometric titration revealed that typical DNA staining protocols designed on the basis of the dye/bp ratio were highly dependent upon the DNA concentration for optimal results. PicoGreen was the least sensitive to the solution dye/bp ratio and was highly fluorescent in the presence of dsDNA. Using this new protocol, accurate histograms of HindIII digested lambda DNA were demonstrated for DNA concentrations ranging from 5 to 2000 ng/mL, and for dye/bp ratios from 106:1 to 1:4 at 0.8 microM of PicoGreen. The new one-step protocol is broadly applicable to any sensitive, laser-induced fluorescence method for detection of nucleic acids.
Coloring Agents↗
Neuregulin in cardiac hypertrophy in rats with aortic stenosis. Differential expression of erbB2 and erbB4 receptors.
BACKGROUND: Neuregulins are a family of peptide growth factors that promote cell growth and viability. The potential role of neuregulin-erbB signaling in hypertrophic growth and later failure in the adult heart in vivo is not known. METHODS AND RESULTS: We used ribonuclease protection assays to quantify mRNA levels of neuregulin, erbB2, and erbB4 in left ventricular (LV) tissue and myocytes of normal rats and rats with aortic stenosis with pressure-overload hypertrophy 6 and 22 weeks after banding. At both stages of hypertrophy, Northern blot analyses of mRNA from LV myocytes showed upregulation of atrial natriuretic peptide, a molecular marker of hypertrophy (P<0.05). LV tissue neuregulin message levels were similar in animals with aortic stenosis compared with controls (P=NS) and were not detectable in myocytes. LV erbB2 and erbB4 message levels in LV tissue and myocytes were maintained during early compensatory hypertrophy in 6-week aortic stenosis animals compared with age-matched controls; in contrast, erbB2 and erbB4 message levels were depressed in 22-week aortic stenosis animals at the stage of early failure (both P<0.01 vs age-matched controls). Immunoblotting of erbB2 and erbB4 also showed normal protein levels in 6-week aortic stenosis animals compared with controls; however, erbB2 and erbB4 protein levels were depressed in 22-week aortic stenosis animals (48% decrease in erbB2, P<0.05, and 43% decrease in erbB4, P<0.01) relative to age-matched controls. CONCLUSIONS: The neuregulin receptors erbB2 and erbB4 are downregulated at both the message and protein levels at the stage of early failure in animals with chronic hypertrophy secondary to aortic stenosis. These data suggest a role for disabled erbB receptor signaling in the transition from compensatory hypertrophy to failure.
Animals↗
Extraction and identification of antioxidants in the roots of yacon (Smallanthus sonchifolius).
Yacon, Smallanthus sonchifolius (Poepp. & Endl.) H. Robinson, Asteraceae, an important economic species grown for its juicy tuberous root, is potentially beneficial in the diet to diabetics. The antioxidative activity of yacon root was studied by 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay. Antioxidants were extracted by methanol and isolated and purified by gel permeation chromatography and preparative reverse-phase HPLC. Two of the major antioxidants were identified as chlorogenic acid and tryptophan by NMR and mass spectrometry.
Antioxidants↗
Nonparametric estimation of bounded survival functions with censored observations.
Stochastic ordering of survival functions is a useful concept in many areas of statistics, especially in nonparametric and order restricted inferences. In this paper we introduce an algorithm to compute maximum likelihood estimates of survival functions where both upper and lower bounds are given. The algorithm allows censored survival data. In a simulation study, we found that the proposed estimates are more efficient than the unrestricted Kaplan-Meier product limit estimates both with and without censored observations.
Algorithms↗
Activation of inwardly rectifying K+ channels by distinct PtdIns(4,5)P2 interactions.
Direct interactions of phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2) with inwardly rectifying potassium channels are stronger with channels rendered constitutively active by binding to PtdIns(4,5)P2, such as IRK1, than with G-protein-gated channels (GIRKs). As a result, PtdIns(4,5)P2 alone can activate IRK1 but not GIRKs, which require extra gating molecules such as the beta gamma subunits of G proteins or sodium ions. Here we identify two conserved residues near the inner-membrane interface of these channels that are critical in interactions with PtdIns(4,5)P2. Between these two arginines, a conservative change of isoleucine residue 229 in GIRK4 to the corresponding leucine found in IRK1 strengthens GIRK4-PtdIns(4,5)P2 interactions, eliminating the need for extra gating molecules. A negatively charged GIRK4 residue, two positions away from the most strongly interacting arginine, mediates stimulation of channel activity by sodium by strengthening channel-PtdIns(4,5)P2 interactions. Our results provide a mechanistic framework for understanding how distinct gating mechanisms of inwardly rectifying potassium channels allow these channels to subserve their physiological roles.
Amino Acid Sequence↗
Origination of Ds elements from Ac elements in maize: evidence for rare repair synthesis at the site of Ac excision.
Although it has been known for some time that the maize transposon Ac can mutate to Ds by undergoing internal deletions, the mechanism by which these mutations arise has remained conjectural. To gain further insight into this mechanism in maize we have studied a series of Ds elements that originated de novo from Ac elements at known locations in the genome. We present evidence that new, internally deleted Ds elements can arise at the Ac donor site when Ac transposes to another site in the genome. However, internal deletions are rare relative to Ac excision footprints, the predominant products of Ac transposition. We have characterized the deletion junctions in five new Ds elements. Short direct repeats of variable length occur adjacent to the deletion junction in three of the five Ds derivatives. In the remaining two, extra sequences or filler DNA is inserted at the junction. The filler DNAs are identical to sequences found close to the junction in the Ac DNA, where they are flanked by the same sequences that flank the filler DNA in the deletion. These findings are explained most simply by a mechanism involving error-prone DNA replication as an occasional alternative to end-joining in the repair of Ac-generated double-strand breaks.
DNA Repair↗
Mucoepidermoid carcinoma of the eyelid skin.
PURPOSE: Mucoepidermoid carcinoma involving the eye or its adnexa generally arises from the conjunctiva. We describe a nodular lesion of the lower eyelid skin with histologic features consistent with low-grade mucoepidermoid carcinoma. METHOD: Case report. RESULTS: By histology, the tumor demonstrated areas of squamous cell carcinoma and scattered islands of mucin-secreting cells. Histochemistry showed hyaluronidase-resistant mucin and intense immunoreactivity with an antibody against carcinoembryonic antigen suggesting that the tumor originated from acrosyringeal structures. CONCLUSIONS: To our knowledge, this is the first report of a mucoepidermoid carcinoma arising from sweat glands in the eyelid skin.
Aged↗
Molecular dissection of the role of histidine in nickel hyperaccumulation in Thlaspi goesingense (Hálácsy).
To understand the role of free histidine (His) in Ni hyperaccumulation in Thlaspi goesingense, we investigated the regulation of His biosynthesis at both the molecular and biochemical levels. Three T. goesingense cDNAs encoding the following His biosynthetic enzymes, ATP phosphoribosyltransferase (THG1, GenBank accession no. AF003347), imidazoleglycerol phosphate dehydratase (THB1, GenBank accession no. AF023140), and histidinol dehydrogenase (THD1, GenBank accession no. AF023141) were isolated by functional complementation of Escherichia coli His auxotrophs. Northern analysis of THG1, THD1, and THB1 gene expression revealed that each gene is expressed in both roots and shoots, but at the concentrations and dosage times of Ni treatment used in this study, these genes failed to show any regulation by Ni. We were also unable to observe any increases in the concentration of free His in root, shoot, or xylem sap of T. goesingense in response to Ni exposure. X-ray absorption spectroscopy of root and shoot tissue from T. goesingense and the non-accumulator species Thlaspi arvense revealed no major differences in the coordination of Ni by His in these tissues. We therefore conclude that the Ni hyperaccumulation phenotype in T. goesingense is not determined by the overproduction of His in response to Ni.
ATP Phosphoribosyltransferase↗
Sustained effects of repeated restraint stress on muscle and adipocyte metabolism in high-fat-fed rats.
Repeated restraint stress 3 h/day for 3 days in rats causes a temporary hypophagia but a sustained weight loss. We investigated whether poststress changes in peripheral tissue metabolism contributed to these responses. One day after the last restraint, insulin sensitivity, measured by oral glucose tolerance test, was improved in restrained rats. Restraint and pair-fed rats weighed less than controls, but body fat content was the same in all groups. Muscle glucose uptake, measured in vitro, was not changed by treatment, whereas in vitro adipocyte glucose uptake was substantially inhibited only in restrained rats. Adipocytes from restrained rats had elevated rates of fatty acid oxidation but not fatty acid esterification, indicating a shift in energy supply from glucose to fatty acids. Five days after the last restraint, the reduced weight of restrained and pair-fed rats resulted from loss of both lean and fat tissue. These results demonstrate that restraint caused sustained, tissue-specific changes in metabolism that may contribute to changes in body composition and body weight of the rats.
Adipose Tissue↗
Fucoxanthin as the major antioxidant in Hijikia fusiformis, a common edible seaweed.
The radical scavenging activity of Japanese edible seaweeds was screened by the DPPH (1-diphenyl-2-picrylhydrazyl) assay to evaluate the DPPH radical scavenging activity in organic extracts. The fresh brown alga Hijikia fusiformis showed the strongest DPPH radical scavenging activity, followed by Undaria pinnatifida and Sargassum fulvellum. The major active compound from Hijikia fusiformis in its acetone extract was identified as fucoxanthin by 13C-NMR spectroscopy.
Antioxidants↗
The effect of latanoprost and brimonidine on rabbit subconjunctival fibroblasts.
PURPOSE: Subconjunctival fibroblasts play a critical role in scarring and treatment failure in fistulizing surgery for glaucoma. The proliferation of subconjunctival fibroblasts appears to be modulated by topical glaucoma medications. This study was conducted to evaluate the effects of latanoprost and brimonidine on subconjunctival fibroblast proliferation in rabbit eyes. METHODS: Twelve pigmented Dutch-belted rabbits were divided into treatment groups of four: latanoprost 0.005%, brimonidine 0.2%, or balanced saline solution (BSS) each were administered to one treatment group, both eyes of each rabbit, twice a day, 6 days a week for 10 weeks. The eyes were then enucleated along with the conjunctiva, fixed, processed, and evaluated by light microscopy and immunohistochemistry using anti-proliferating cell nuclear antigen (PCNA) and anti-muscle-specific actin antibody (HHF-35). Fibroblast cell counts were performed at magnification x40. RESULTS: In all groups, few inflammatory cells were seen in the subconjunctival space under light microscopy. PCNA staining revealed a statistically significant increase in the mean number of labeled fibroblasts in the group receiving brimonidine compared with the control (BSS) group. The group receiving latanoprost also had a significantly higher mean number of labeled fibroblasts than the groups receiving brimonidine or BSS. Only a few fibroblasts stained positively with the anti HHF antibody. Eyes treated with latanoprost, however, had significantly higher numbers of positively labeled cells than eyes treated with brimonidine or BSS. CONCLUSION: When applied to rabbit eyes, latanoprost and brimonidine appear to increase the number of positively labeled proliferating subconjunctival fibroblasts.
Adrenergic alpha-Agonists↗
[CAG trinucleotide mutation detection in patients with hereditary spinocerebellar ataxia].
OBJECTIVE: To assess the frequency of the SCA1, SCA2,SCA3/MJD, SCA6, SCA7 and DRPLA CAG trinucleotide repeat expansions(CAG)n among individuals diagnosed with hereditary spinocerebellar ataxia(SCA) from Chinese families. METHODS: The SCA1, SCA2, SCA3/MJD, SCA6, SCA7 and DRPLA(CAG)n mutations were detected by polymerase chain reaction (PCR), denaturing polyacrylamide gel electrophoresis and silver staining technique in 167 patients with autosomal dominant SCA from 85 Chinese families and 37 sporadic SCA patients. RESULTS: Among 85 families, four families(4.70%) had seven SCA1 patients with the CAG repeat expanded to 53 to 62 repeats, five (5.88%) had twelve SCA2 patients with the CAG repeat expanded to 43 to 47 repeats, and 41 (48.23%) had 83 SCA3/MJD patients with the CAG repeat expanded to 68 to 83 repeats. Analysis of the mutation in these families showed a strong negative correlation between the size of the expanded CAG repeat and the age of disease onset. None of the SCA patients were positive for SCA6, SCA7, or DRPLA. Nor was any of the sporadic SCA patients positive for the CAG repeat expansion in the SCA1, SCA2, SCA3/MJD, SCA6, SCA7, or DRPLA gene. CONCLUSION: The frequency of SCA3/MJD is substantially higher than that of SCA1 and SCA2 in the autosomal dominant SCA from Chinese families. Chinese SCA3/MJD patients are non-Portuguese. Clinical expressions of the various SCAs overlap one another and hence can make the phenotype-based diagnostic classification inaccurate in many instances. It is important for SCA clinical studies to make an SCA gene diagnosis and genotype analysis.
Adult↗
[Observation on left ventricular remodeling in acute myocardial infarction].
OBJECTIVE: After an acute myocardial infarction (AMI), there will be regional dilation and global remodeling of the infarcted left ventricle. This study was aimed to observe the features of the ventricular remodeling after AMI. METHODS: Based on the time of onset of the symptoms, 37 patients (pts) with AMI were divided into 4 groups. The time of onset of AMI for group 1 (16 pts), group 2 (7 pts), group 3 (11 pts) and group 4 (3 pts) was < or = 3 hours (hrs), > 3 hrs - < or = 6 hrs, > 6 hrs - < or = 12 hrs and > 12 hrs respectively. The size of the left ventricle in all the patients were analysed with resting myocardial gated SPECT (GSPECT). Tc-99m MIBI was infused at admission and data of GSPECT were collected 2 hours later following the infusion. End-diastolic volume (EDV), end-systolic volume (ESV) and LVEF were shown by the system. Stroke volume (SV) was then calculated. RESULTS: EDV for group 1 to 4 was (98.5 +/- 31.9) ml, (99.4 +/- 55.6) ml, (128.1 +/- 55.1) ml and (140.0 +/- 25.3) ml, respectively. ESV for group 1 to 4 was (57.0 +/- 30.9) ml, (55.1 +/- 40.3) ml, (77.4 +/- 39.8) ml and (81.3 +/- 26.0) ml, respectively. SV for group 1 to 4 was (57.0 +/- 30.9) ml, (55.1 +/- 40.3) ml, (77.4 +/- 39.8) ml and (81.3 +/- 26.0) ml, respectively. LVEF for group 1 to 4 was (44.6 +/- 13.1) ml, (49.7 +/- 13.1) ml, (42.8 +/- 13.5) ml, and (42.7 +/- 8.6) ml, respectively. In pts with anterior infarction, EDV, ESV and SV after 6 hrs of the onset of AMI were greater than those in pts with in 6 hrs of the onset. It was the same in pts with inferior infarction. CONCLUSION: It is suggested that the left ventricular size increased in 3 hrs after AMI. Following the initial dilation of left ventricle, EDV, ESV and SV did not change significantly with in 6 hrs, but then increased gradually after 6 hrs from the onset of the symptoms. The early and significant dilation of left ventricle after AMI may be one of the risk factors of severe cardiac events.
Aged↗
[A longitudinal research on palate growth in the normal mixed dentition by three-dimensional image analysis].
OBJECTIVE: To investigate the trait of the palate growth and to provide a method of three-dimensional image analysis on revealing the entire variation of palate. METHODS: A longitudinal study on the palate growth of 30 subjects (male 8, female 22) with normal occlusion during mixed dentition was carried out by three-dimensional image analysis. The observation period was from 7 to 10 years of age. RESULTS: During growth, the palate vaults in 16 cases (53%) descend for 1-5 mm, whereas, the palate vaults in 14 cases (47%) ascend for 2.6 mm at most. CONCLUSION: The variations of palate growth can be investigated by three-dimensional image analysis. During growth, the palate vault may descend or ascend, which shows the individual differences of oronasal function.
Adolescent↗
[The detection of microsatellite instability in carcinoma and adenoma of large bowel and its significance].
OBJECTIVE: To explore the role of microsatellite instability (MSI) in colorectal carcinogenesis and the relationship between MSI, proliferation activity and prognosis. METHODS: PCR-SSLP and immunohistochemistry methods were used to detect MSI and the expression of PCNA in 56 cases of carcinomas, 9 cases of adenomas and 6 cases of adenomas with malignant changes. RESULTS: The total positive rate of MSI were 25/56 cases in colorectal carcinomas. The MSI positive cases were 3/4 in HNPCCs, 22/52 in sporadic colorectal carcinomas, 2/9 in adenomas and 2/6 in adenoma with malignant changes respectively. The PCNA labelling index of MSI positive tumors were significantly lower than that of MSI negative tumors (P < 0.01). The 3 and 5 year survival rates in patients with MSI positive colorectal carcinomas were higher than those of MSI negative tumors. CONCLUSION: MSI may be an early molecular alteration and another molecular mechanism in colorectal carcinogenesis. The MSI positive tumors have low proliferating activity and a better clinical outcome. The detection of MSI might be useful in predicting prognosis of colorectal carcinomas.
Adenoma↗
[Clinicopathological study of mucosa-associated lymphoid tissue lymphoma of salivary glands].
OBJECTIVE: To study the histopathological features and pathogenesis of mucosa associated lymphoid tissue lymphoma (MALT-oma) of salivary glands. METHODS: Surgical specimens from 27 cases of MALT-oma of salivary glands were studied using paraffin-embedded section, immunohistochemical method (SP method) and electron microscope. RESULTS: 12 tumors were located in the pariotid glands, the other 15 in the submandibular glands. Much of the MALT-oma of the salivary glands were composed of diffuse centrocyte-like (CCL) cells with "lymphoepithelial lesions". Immunohistochemically, CD20 expression was found to be positive and CD45RO expression was negative in all MALT-omas of salivary glands. CONCLUSIONS: Most of the MALT-omas are low grade malignant tumors and the tumor cells have a "homing back" phenomenon. A small number of MALT-omas can become highly malignant tumors with poor prognosis. Acquired MALT may develop as a reaction to autoimmune disease and/or infection. Hyperimmune reaction and MALT hyperplasia under continuous stimulation may result in myoepithelial sialadenitis and develop into MALT-oma of salivary glands.
Adolescent↗