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Biomedical subjects

X Cui

Publications and source records attributed to X Cui.

At least 109 records · Page 6Linked to original sources
PubMed1998

Kinetic alterations of angiotensin-II and nitric oxide in radiation pulmonary fibrosis.

We studied the kinetic alterations of angiotensin-II (A-II) and nitric oxide (NO) in radiation pulmonary fibrosis (RPF) to determine the roles of these two types of vasoactive substances in the pathogenesis of RPF. We irradiated the right hemithorax of male Wistar rats with single doses of 0, 15, and 30 Gy of 60Co gamma rays and we examined the lung parenchyma at 1, 3, 5, and 7 months following the radiation. The rats were killed at the stated intervals and samples were obtained from the right lung. We measured types I and III procollagen mRNA by in situ hybridization and demonstrated the synthesis and distribution of A-II in the pulmonary tissue by immunohistochemistry. The formation and kinetic alterations of types I and III collagen were analyzed under polarized light microscope using Sirius Red stain. The hydroxyproline (Hyp) content was measured in the pulmonary tissue after digestion with HCl. A-II radiation immunoactivity (RIA) was assayed in pulmonary tissue homogenate. Pulmonary NO content, NO synthase (NOS), and the angiotensin converting enzyme (ACE) activities were also measured. Our results showed that types I and III collagen genes began to be expressed 1 month after irradiation. Type I collagen gene increased significantly, reaching its peak 3 months after irradiation. As the irradiation dosage was increased from 15 to 30 Gy, the type I collagen gene content increased significantly, while type III significantly decreased. The Hyp content increased with the passage of time after irradiation. Pulmonary A-II RIA increased significantly with the dose of irradiation and was chiefly produced by fibroblasts and macrophages in the interstitium, bronchiolar epithelium, and the anteriolar wall. Pulmonary NO and NOS activities decreased following irradiation. One month following irradiation, the expression of the type I collagen gene begins to increase, with a significant increase in both Hyp and type I collagen 3 months after irradiation. The histogenesis of RPF may be related to A-II. The interstitial cells, the bronchiolar epithelium, and the arteriolar wall can produce A-II and need not pass through the ACE pathway. Our results suggest that the A-II increase and NO decrease may have a role in the pathogenesis of RPF.

Angiotensin II↗
PubMed1998

The protective action of taurine and L-arginine in radiation pulmonary fibrosis.

Taurine has the ability to resist the action of oxygen-free radicals by protecting cytomembranes. L-arginine increases the nitric oxide in the organism, inhibiting some types of abnormal cell proliferation. We examined the actions and protective mechanisms of these two substances against radiation pulmonary fibrosis. The mRNA transcription and the distribution of pulmonary types I and III procollagen were measured by in situ hybridization. Type I and type III collagen in the interalveolar septa and the change ratio between the two types were assayed using Sirius Red staining and polarizing microscopy. Angiotensin converting enzyme (ACE), hydroxyproline (Hyp), malondialdehyde (MDA), and nitric oxide (NO) were measured in lung tissue after irradiation. We found that, following administration of taurine or arginine, the mRNA transcription of procollagen types I and III significantly decreased in the pulmonary tissue 3 months after irradiation and the Hyp content was lower, especially after the administration of arginine. The extent of the radiation-induced decrease in ACE activity was markedly attenuated. As a substrate of NO production, arginine can significantly increase the pulmonary NO content. We conclude that the administration of taurine or arginine can significantly decrease the mRNA transcription of procollagen and the synthesis of type I collagen in the interalveolar septa and can decrease the Hyp content of the pulmonary tissue. Following irradiation, NO can attenuate the radiation-induced decrease in ACE activity. Our study suggests that exogenous NO and taurine significantly protect against radiation pulmonary injury.

Animals↗
PubMed1998

Preventive effects of selenium-enriched spiruline (SESP) on radiation pneumonitis.

We studied the early effects of selenium-enriched spiruline (SESP) on radiation-induced pulmonary fibrosis using histopathology, cDNA-mRNA dot-blot hybridization, and a biochemical technique for quantifying the hydroxyproline content. We found marked lung injury in the irradiated group, whereas only slight hyperemia, hemorrhage, exudation, and thickness of the interalveolar wall in the lung in the selenium-treated group. The hydroxyproline (hyp) content in the lungs and the synthesis of type III collagen mRNA decreased in the SESP-treated group. Selenium-enriched spiruline may have a protective effect on the development of radiation pneumonitis.

Animals↗
PubMed1998

Transmission and natural regulation of infection with Ascaris lumbricoides in a rural community in China.

A longitudinal study on a cohort of 215 people who remained untreated from June 1993 to June 1994 was carried out using fecal egg counts to examine the course of transmission and aspects of the natural regulation of the infection with Ascaris lumbricoides. The results indicate that the parasite population remained relatively stable during the years since overall prevalence remained steady above 60%. About 40% of the people in the cohort retained their infection intensity status throughout the year, in terms of light, medium, and heavy infections. The regulation of infection in the population could be attributed to the tendency for the loss of worms from people with initial light infections and the movement to medium infection intensity status of people with both light and heavy infections. Compared with adults, children showed a stronger tendency of retaining initial medium infections but weaker tendencies for keeping initial light infections and clearing themselves of infection. Predisposition to light and medium infections was detected in people who had experienced an uninfected period of 4-12 mo before reinfection was established.

Adolescent↗
PubMed1997

ALK, the chromosome 2 gene locus altered by the t(2;5) in non-Hodgkin's lymphoma, encodes a novel neural receptor tyrosine kinase that is highly related to leukocyte tyrosine kinase (LTK)

Anaplastic Lymphoma Kinase (ALK) was originally identified as a member of the insulin receptor subfamily of receptor tyrosine kinases that acquires transforming capability when truncated and fused to nucleophosmin (NPM) in the t(2;5) chromosomal rearrangement associated with non-Hodgkin's lymphoma, but further insights into its normal structure and function are lacking. Here, we characterize a full-length normal human ALK cDNA and its product, and determine the pattern of expression of its murine homologue in embryonic and adult tissues as a first step toward the functional assessment of the receptor. Analysis of the 6226 bp ALK cDNA identified an open reading frame encoding a 1620-amino acid (aa) protein of predicted mass approximately 177 kDa that is most closely related to leukocyte tyrosine kinase (LTK), the two exhibiting 57% aa identity and 71% similarity over their region of overlap. Biochemical analysis demonstrated that the approximately 177 kDa ALK polypeptide core undergoes co-translational N-linked glycosylation, emerging in its mature form as a 200 kDa single chain receptor. Surface labeling studies indicated that the 200 kDa glycoprotein is exposed at the cell membrane, consistent with the prediction that ALK serves as the receptor for an unidentified ligand(s). In situ hybridization studies revealed Alk expression beginning on embryonic day 11 and persisting into the neonatal and adult periods of development. Alk transcripts were confined to the nervous system and included several thalamic and hypothalamic nuclei; the trigeminal, facial, and acoustic cranial ganglia; the anterior horns of the spinal cord in the region of the developing motor neurons; the sympathetic chain; and the ganglion cells of the gut. Thus, ALK is a novel orphan receptor tyrosine kinase that appears to play an important role in the normal development and function of the nervous system.

Amino Acid Sequence↗
PubMed1997

The HRX proto-oncogene product is widely expressed in human tissues and localizes to nuclear structures.

Chromosomal rearrangement of the HRX (MLL, ALL-1, Htrx) gene situated at chromosome band 11q23 is one of the most frequent genetic changes in infant leukemias of myeloid and lymphoid lineage and in treatment-induced secondary leukemias. The HRX gene codes for a predicted 431-kD protein that shows significant homology to the Drosophila trithorax protein, an Hox epigenetic regulator. Typically, the region encoding the HRX gene is rearranged, mostly in reciprocal translocations with a number of partners, resulting in a range of fusion genes. However, this is not the only abnormality affecting HRX because partial duplication of the gene, as well as interstitial deletions, can occur. Despite extensive studies of HRX at the genetic level, the protein products of the HRX gene and their patterns of expression in normal and leukemic cells remain uncharacterized. In this study we analyzed the distribution and localization of HRX proteins in cell lines and human tissues, using both polyclonal and monoclonal antibodies. The specificity of these reagents was confirmed using cells transfected with the HRX-ENL fusion gene. Western blot analyses of protein extracts from cells carrying the t(11;19) and t(4;11) translocations showed HRX chimeric proteins whose migrations corresponded to the sizes predicted from analyses of translocation-induced fusion mRNAs expressed by the derivative 11 chromosomes. Immunocytochemical analysis showed a punctate distribution of wild-type and chimeric HRX proteins within cell nuclei, suggesting that HRX localizes to nuclear structures in cells with and without 11q23 translocations. Nuclear staining was found in the majority of tissues studied with the strongest reactivity in cerebral cortex, kidney, thyroid, and lymphoid tissues. Thus, HRX is widely expressed in most cell types including hematopoietic cells, a finding that precludes an immunocytochemical approach for diagnosis of leukemias bearing 11q23 structural abnormalities.

Animals↗
PubMed1997

Detection of the t(2;5)(p23;q35) and NPM-ALK fusion in non-Hodgkin's lymphoma by two-color fluorescence in situ hybridization.

The non-Hodgkin's lymphoma (NHL) subset commonly referred to as large cell lymphoma (LCL) has historically been characterized by it's marked cytological, immunological, and clinical heterogeneity. One potential defining feature of these lymphomas, the t(2;5)(p23;q35), occurs in 25% to 30% of anaplastic LCLs and is also found in cases with diffuse large cell or immunoblastic morphology. We recently identified nucleophosmin (NPM) and anaplastic lymphoma kinase (ALK) as the genes on chromosomes 5 and 2, respectively, that are juxtaposed by this translocation. To provide a complementary approach to the use of classical cytogenetics or polymerase chain reaction-based methods for the detection of this abnormality, we have developed a two-color fluorescent in situ hybridization (FISH) assay for the t(2;5) that may be used for the analysis of both interphase nuclei and metaphase chromosomes. Three overlapping chromosome 5 cosmid clones located immediately centromeric to the NPM gene locus and an ALK P1 clone located telomeric to the chromosome 2 breakpoint were labeled with digoxigenin or biotin, respectively, and used to visualize the derivative chromosome 5 produced by the t(2;5), evident as juxtaposed or overlapping red and green fluorescent signals. This NPM-ALK FISH assay was initially validated by analysis of a series of cytogenetically characterized cell lines, with the presence of the der(5) chromosome showed specifically only in those lines known to contain the t(2;5). The assay was then applied in a blinded fashion to a series of eight cytogenetically t(2;5)-positive clinical specimens and seven known t(2;5)-negative cases, including three NHL and four Hodgkin's disease biopsy samples. Whereas the t(2;5)-negative cases were negative by FISH, all eight t(2;5)-positive cases were positive. One additional case, initially thought to be positive for the translocation by cytogenetics, was proven to not be a classic t(2;5) by interphase and metaphase FISH. These data indicate that the FISH assay described is a highly specific and rapid test that should prove to be a useful adjunct to the currently available methods for detection of the t(2;5).

Anaplastic Lymphoma Kinase↗
PubMed1997

Thyroid hormone induces beta1-adrenergic receptor gene transcription through a direct repeat separated by five nucleotides.

Transcription of the rat gene for the beta1-adrenergic receptor (beta1-AR) is stimulated by thyroid hormone (T3) in ventricular myocytes. To identify the domains involved in the regulation of beta1-AR gene transcription by T3, three kb of 5'-flanking sequence of the rat beta1-AR gene were ligated to a luciferase reporter gene and transiently transfected into ventricular myocytes. By generating deletions in the rat beta1-AR promoter, a region between -125 and -100 was found to mediate a three-fold induction by T3. This element was able to confer T3 responsiveness to a neutral promoter driving the luciferase reporter gene. Through site directed mutagenesis of this region, it was determined that the T3 responsive element (TRE) was organized as a direct repeat separated by five nucleotides in which the 5'-most AGGTCG half-site was between nucleotides -105 to -102 and the 3'-most AGGTCA half-site between nucleotides -116 and -113. Both the thyroid hormone receptor isoforms alpha and beta bound to the oligomer representing the sequences between -125 and -100 most efficiently as heterodimers with the retinoid X receptor. This TRE is unusual in that it is a direct repeat separated by five nucleotides which is located 3' to the transcriptional start site.

Animals↗
PubMed1997

Discriminating between allelic and interlocus differences among human immunoglobulin VH4 sequences by analyzing single spermatozoa.

To address the challenging issue of distinguishing allelic and interlocus differences among repetitive sequences, human immunoglobulin VH4 loci in the parental haplotypes of 13 donors were determined by analyzing single spermatozoa. VH4 sequences detected among these donors were assigned to their corresponding loci based on the fact that allelic sequences usually segregate into different gametes. Four out of the ten VH4 loci were shown to contain null alleles that are undetectable with diploid materials. The distribution of the allelic variation within the analyzed regions at the VH4 loci is highly biased.

Alleles↗
PubMed1997

Promoter analysis of the rat beta1-adrenergic receptor gene identifies sequences involved in basal expression.

The beta1-adrenergic receptor (beta1-AR) mediates several functions of catecholamines in the heart, including the stimulation of heart rate and contractility. The expression of the rat beta1-AR gene was assessed by transiently transfecting chimeric genes containing the beta1-AR promoter, driving the luciferase reporter gene into various cell lines. beta1-AR/luciferase vectors containing 3 kb of the 5'-flanking region and extending to -126 relative to the start site of translation were expressed at high levels in ventricular myocytes, SK-N-MC cells, and HepG2 cells. The addition of 26 nucleotides from -125 to -100 to the -3311 beta1-AR/luciferase chimeric gene reduced expression in myocytes and SK-N-MC cells while eliminating expression in HepG2 cells. This element is located 125 base-pairs 3' to the transcriptional start site. The mutation of four nucleotides between -121 and -118 diminished the inhibitory effect of this element. The inhibitory activity of the -125 to -100 sequence was completely dependent on promoter context and positioning. In addition to this 3' element, sequences between -3311 and -2740 in the 5'-flanking region of the beta1-AR gene were required for the full transcriptional suppression. Using DNase I footprinting and gel mobility assays, it was determined that within the 26-bp region, rat heart nuclear proteins bound to two sites between nucleotides -123 and -112 and -106 and -100. Therefore, appropriate basal expression of the beta1-AR gene involves widely separated sequences 3' and 5' to the transcriptional start site.

Animals↗
PubMed1997

[Studies on cell senescence induced by D-galactose in cultured neurons and fibroblasts].

The cell senescence induced by D-galactose (D-gal) in cultured rat fetal brain neurons and human fetal lung fibroblast was investigated in vivo and in vitro. The results showed pronounced decreases in nerve cell diameters, number of process and percentage of multiprocess neurons including "pyramidal" and "stellate" shaped and a rather high level of mortality rate observed in D-gal-treated (8 g/L) neurons. Lessening of the proliferating population of lung fibroblast taken from rat treated with D-gal (50 mg/kg.d, subcutanous injection for 6 weeks) was observed. We have also determined the changes of cell cycle in human fetal lung fibroblast cells treated with D-gal (8 g/L): the proportion of the G0-G1 cells increased but the G2-M and DNA level and the results showed that decreased and the cell growth rate declined in comparison with those of the control. Lipid peroxidation was observed in both kinds of cells because D-gal was proved to have action of decreasing SOD activity and increasing MDA content, the results found in D-gal-treated rats were similar to those observed in hypoxanthine-xanthine oxidation reaction system (O2-), indicating that reactive oxygen was generated in the course of D-gal metabolism. It is concluded that D-gal has the hastening effect on cell senescence and oxidative stress might be responsible for this aging effect.

Aging↗
PubMed1997

[A simple nitric oxide exposure system for small animals].

A nitric oxide exposing system was designed for experimental research, which consist of equipments such as plexiglass chamber, blower, flowmeter, NO/N2 cylinder, pure O2 cylinder, NOx analyzer, and O2/CO2 monitor. The efficacy of the whole system has been verified through our practice as shown by the following results: measured NO inside the chamber were close to designed NO concentration, measured O2 concentrations in the chamber were similar to that of the atmosphere, and the highest nitrogen dioxide (NO2) and carbon dioxide (CO2) concentrations were lower than 3 ppm and 0.3% respectively. The experimental facility is simple in construction, easy to be operated and convenient for research on effects and toxicity of long-term inhaled nitric oxide in small animals.

Administration, Inhalation↗
PubMed1997

[Effect of cigarette smoking on lipid peroxidation and antioxidation in rat lens].

The effects of cigarette smoking on lipid peroxidation, the activities of antioxidases, and the level of non-protein sulphydryl group in the rat lenses were investigated. The results showed that compared with the control group, MDA contents were significantly higher, while the wet weight of lenses, the concentration of non-protein sulphydryl group, the activities of superoxide dismutase and glutathione peroxidase were significantly decreased in the smoking rats. This study suggested that cigarette smoking might be involved in the development of cataract.

Animals↗
PubMed1997

[Observation on human embryonic lung fibroblast proliferation mediated by mitogen activated protein kinase].

OBJECTIVE: To study the effect of mitogen activated protein kinase (MAPK) on the proliferation of human embryonic lung fibroblast (HELF) induced by 60Co irradiation and the relationship between MAPK and angiotensin II (A II). METHODS: Cell proliferation was measured with enzyme-labeling method; angiotensin II, MAPK and type I precollagen synthesis as well as the role of sodium nitroprusside on the inhibition of A II were evaluated adopting immunohistochemical technique combined with image analysis after 1-5 Gy 60Co gamma-ray irradiation on the cultured HELF. RESULTS: Irradiation at 1-5 Gy promoted cell proliferation and type I precollagen synthesis; the syntheses of A II and MAPK were also increased in the irradiated cells. Exogenous A II enhanced cell proliferation, but sodium nitroprusside inhibited the action of A II. CONCLUSIONS: HELF proliferation induced by 60Co irradiation is a chain reactive course, in which, A II and MAPK are involved. MAPK may play a role of limiting valve in the signal transduction of cellular proliferation.

Angiotensin II↗
PubMed1997

[Experimental comparison of two coxsackievirus B3 variants in murine myocardial cells].

There is lack of direct evidence whether the myocarditis can be induced by CVB3o. The two coxsackievirus B3 variants were used to infected murine myocardial cells. The results showed that: (1) In culture medium of murine myocardial cells infected with two variants, it did not show much differences in titers at 12 and 24 hours between CVB3o and CVB3m. (2) The two variants could all induce the death of myocardium, but with the elapse of time, the cell death rate of CVB3m infected cells was much higher than CVB3o. (3) CVB3o could not block the myocardial cells from infection by CVB3m. It is concluded that myocardial cells can be infected by CVB3o, but the degree of infection is lower than CVB3m.

Animals↗
PubMed1996

The gene encoding LERK-7 (EPLG7, Epl7), a ligand for the Eph-related receptor tyrosine kinases, maps to human chromosome 5 at band q21 and to mouse chromosome 17.

The eph-related receptors are the largest subfamily of receptor tyrosine kinases. Recently, we and others have identified seven different, but related, cDNAs encoding membrane-bound ligands for this family of receptors. One member, LERK-7, is attached to the cell membrane via glycosyl-phosphatidylinositol linkage and has been found to be a ligand for the eph-family receptors hek, elk, eck, and rek. Using PCR-based screening of human x rodent somatic cell hybrid DNAs, we have assigned the gene that encodes LERK-7 (EPLG7) to human chromosome 5. Fluorescence in situ hybridization to metaphase chromosome preparations using a genomic clone from the locus refined this localization to chromosome 5, band q21. In addition, Southern blot analysis of DNAs from interspecific backcross mice indicated that the mouse homologue Epl7 maps to a homologous region on chromosome 17.

Animals↗
PubMed1996

The rf2 nuclear restorer gene of male-sterile T-cytoplasm maize.

The T cytoplasm of maize serves as a model for the nuclear restoration of cytoplasmic male sterility. The rf2 gene, one of two nuclear genes required for fertility restoration in male-sterile T-cytoplasm (cmsT) maize, was cloned. The protein predicted by the rf2 sequence is a putative aldehyde dehydrogenase, which suggests several mechanisms that might explain Rf2-mediated fertility restoration in cmsT maize. Aldehyde dehydrogenase may be involved in the detoxification of acetaldehyde produced by ethanolic fermentation during pollen development, may play a role in energy metabolism, or may interact with URF13, the mitochondrial protein associated with male sterility in cmsT maize.

Acetaldehyde↗