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Biomedical subjects

Y Xia

Publications and source records attributed to Y Xia.

At least 271 records · Page 15Linked to original sources
PubMed1995

Modulation of neutrophil influx in glomerulonephritis in the rat with anti-macrophage inflammatory protein-2 (MIP-2) antibody.

The role of the chemokine, macrophage inflammatory protein-2 (MIP-2), during anti-glomerular basement membrane (GBM) antibody (Ab) glomerulonephritis (GN) was studied. Rat MIP-2 cDNA had been cloned previously. Recombinant rat MIP-2 (rMIP-2) from Escherichia coli exhibited neutrophil chemotactic activity and produced neutrophil influx when injected into the rat bladder wall. By using a riboprobe derived from the cDNA and an anti-rMIP-2 polyclonal Ab, MIP-2 was found to be induced in glomeruli with anti-GBM Ab GN as mRNA by 30 min and protein by 4 h, with both disappearing by 24 h. The expression of MIP-2 correlated with glomerular neutrophil influx. A single dose of the anti-MIP-2 Ab 30 min before anti-GBM Ab was effective in reducing neutrophil influx (40% at 4 h, P < 0.01) and periodic acid-Schiff deposits containing fibrin (54% at 24 h, P < 0.01). The anti-rMIP-2 Ab had no effect on anti-GBM Ab binding (paired-label isotope study). Functional improvement in the glomerular damage was evidenced by a reduction of abnormal proteinuria (P < 0.05). These results suggest that MIP-2 is a major neutrophil chemoattractant contributing to influx of neutrophils in Ab-induced glomerular inflammation in the rat.

Amino Acid Sequence↗
PubMed1995

Involvement of reactive oxygen intermediates in cyclooxygenase-2 expression induced by interleukin-1, tumor necrosis factor-alpha, and lipopolysaccharide.

Reactive oxygen intermediates (ROIs) play an important role in inflammatory processes as mediators of injury and potentially in signal transduction leading to gene expression. Cyclooxygenase (COX) is a rate-limiting enzyme in prostanoid biosynthesis, and its recently cloned inducible form, COX-2, is induced by proinflammatory cytokines. This study linked ROIs to the signaling pathways that induce COX-2 expression. The hydroxyl radical scavengers DMSO (1%), as well as di- and tetramethylthiourea, inhibited IL-1-, TNF alpha-, and LPS-induced COX-2 expression in rat mesangial cells. The suppression of COX-2 mRNA expression correlated with the COX-2 protein level. In comparison with the prolonged induction of the inducible gene encoding protein-tyrosine phosphatase by hydrogen peroxide, the COX-2 gene was only transiently induced. Protein-tyrosine phosphatase is also induced by heat shock and chemical stress, whereas COX-2 is not. Superoxide was a more potent inducer for COX-2 than hydrogen peroxide. In addition, NADPH stimulated COX-2 expression, and an inhibitor of NADPH oxidase blocked COX-2 expression induced by TNF alpha. COX-2 and KC gene expression costimulated by IL-1 were inhibited differentially by the scavengers. These studies demonstrate that oxidant stress is a specific and important inducer of COX-2 gene expression. This induction may contribute to the deleterious amplification of prostanoids in inflammation and compound the direct effects of ROI production.

Animals↗
PubMed1995

Present systems and future needs for risk assessments of biologicals: the perspective of the regulator in the People's Republic of China.

Regulation of veterinary biologicals in the People's Republic of China is governed by the Animal Drug Administration Regulations issued by the State Council in 1987. These regulations authorize the Ministry of Agriculture to prescribe requirements governing the production and marketing of veterinary biologicals shipped into, within or from China. The goal of the veterinary biologicals programme is to ensure that all veterinary biological products are pure, safe, potent and effective. The programme is based on review, licensing, inspection and post-licensing testing. Risk assessment procedures and requirements for biotechnology-derived veterinary biologicals have been established. China needs international harmonization of trade in veterinary biologicals and will make a great contribution in this field.

Animals↗
PubMed1995

Only children and children with siblings in the People's Republic of China: levels of fear, anxiety, and depression.

In 1979, China implemented its one-child-per-family policy in order to control its burgeoning population. Subsequently, concern has been raised about the policy and its potentially negative effects on children. In the present study, we examined these presumed effects on 202 adolescents born before the policy went into effect, 290 preadolescents born during the period in which the policy was being implemented, and 239 children who were born after the policy went into effect. Measures of fear, anxiety, and depression were obtained. Contrary to our hypotheses, based on concerns raised by the one-child policy, children with siblings reported significantly higher levels of fear, anxiety, and depression than only children, regardless of when they were born. For depression, this effect was qualified by a sibling status x age interaction. Children with siblings born after the policy went into effect, or during its implementation, reported higher levels of depression than did only children; however, only children and children with siblings born before the policy went into effect did not differ significantly from one another. Sociocultural factors associated with these findings are explored.

Adolescent↗
PubMed1995

[A comparative study on the effect of absorbable components of several drugs on the growth and population doublings of rat diploid fibroblast].

Embryonic skin fibroblast of Sprague-Dawley rats cultivated in vitro was used in this experiment. The cultural medium was added with absorbable components of several drugs. The result reveals that Yan Shou recipe, vitamin E and Huan Jing Jian have conspicuous promotive effect on the growth of diploid fibroblast and also help to increase population doublings. The experiment suggests that all these drugs possess anti-aging effect on the skin diploid fibroblast of rats.

Aging↗
PubMed1995

[Type B supersonic diagnostic observation on the action of 25 kinds of traditional Chinese medicine on gallbladder movement].

Twenty-five kinds of traditional Chinese medicine (TCM), which are often used in clinic to cure cholelithiasis, were studied for their actions on gallbladder movement in cholelithiasis patients by using a type B supersonic diagnostic set. The results show that among these 25 kinds 15 were of contracting type, 4 were of diastole type and 6 were of contracting and diastole type, thus providing useful experimental criteria for the clinical application of these TCM in cholelithiasis patients.

Adult↗
PubMed1995

[Study on the retrofascial space of the dorsum nasi and its clinical significance].

Fifty-seven adult and two children cadavers were dissected to study the position, size and structure of the retrofascial space of the dorsum nasi. The space lay between the periosteum, perichondrium and the fascia dorsum nasi. The shape of the space is like a pyramid. The space averaged 3.09 +/- 0.66 cm in length. The anatomical characteristics, individual variation and clinical significance of this space were discussed.

Adult↗
PubMed1995

Expression of p53 gene in oral squamous cell carcinoma and its relation with clinical and pathological parameters and prognosis of patients.

One hundred and eleven cases of oral squamous cell carcinoma (OSCC) were examined for overexpression of p53 protein by using immunohistochemical technique. Association between p53 protein overexpression and clinical and pathological parameters as well as prognosis of patients were also analyzed. p53 protein overexpression was commonly observed (69.4%) in OSCC and may be used as a marker of carcinogenesis of OSCC. The level of p53 protein overexpression is correlated with the lower three and five-year survival rate of OSCC. The presence or absence of p53 overexpression was not correlated with sex, age, site of tumor, size of tumor, degree of differentiation, node status, and clinical stage in OSCC. Single factor COX proportional hazards regression model analysis indicated that there was no significant association between p53 overexpression and prognosis of OSCC. Multivariable COX model analysis failed to establish effective life function or risk rate function. These showed that all the parameters analyzed in this study as well as p53 overexpression were not significant and effective risk factors of prognosis for patients with OSCC.

Carcinoma, Squamous Cell↗
PubMed1994

Apolipoprotein-E epsilon-4 is associated with increased neurofibrillary pathology in the Lewy body variant of Alzheimer's disease.

Brains from demented patients with both Alzheimer's disease (AD) pathology and brainstem and neocortical Lewy bodies have fewer neurofibrillary tangles than pure AD, but share with AD an increased apolipoprotein-E epsilon-4 (APOE4) allelic frequency. We applied the Braak and Braak AD neuropathology staging protocol, based on entorhinal and neocortical neurofibrillary pathology, to 40 such Lewy body variants of AD (LBV) and 97 cases of pure AD and compared the results in APOE4 positive and APOE4 negative subgroups. APOE4 was associated with more severe neurofibrillary pathology in LBV but not in pure AD, where a ceiling effect appears to be operative.

Aged↗
PubMed1994

New restriction endonuclease CviRI cleaves DNA at TG/CA sequences.

A new type II restriction endonuclease, CviRI, was isolated from virus XZ-6E infected chlorella cells. CviRI is the first restriction endonuclease to recognize the sequence 5'-TGCA-3' and cleaves DNA between the G and C residues to produce blunt-end termini. Methylation of the adenine or cytosine in 5'-TGCA-3' sequences prevents CviRI cleavage. Due to its sequence specificity, CviRI may be especially useful for detecting mutant alleles of many heritable human genetic diseases.

Animals↗
PubMed1994

The relationship between genetic and physical distances in the cloned a1-sh2 interval of the Zea mays L. genome.

A 470-kb segment from the long arm of chromosome 3 of Zea mays (inbred LH82), encompassing the a1-sh2 interval, was cloned as a yeast artificial chromosome. Comparison of the sizes of the restriction fragments generated from the cloned DNA fragment and from the DNA isolated from the maize inbred line LH82 established the colinearity of the a1-sh2 interval in these DNAs. By utilizing a chromosome fragmentation technique, a yeast artificial chromosome encompassing the a1-sh2 interval was separately fragmented at the a1 and sh2 loci. Comparison of the sizes of these fragmentation products established the physical distance between the a1 and sh2 loci to be 140 kb. Furthermore, these fragmentation experiments established the physical orientation of the a1 and sh2 genes relative to the maize centromere. The molecular cloning of the contiguous region between the a1 and sh2 loci made it possible to define the relationship between physical and genetic distances over a relatively large segment of the maize genome. In this interval, the relationship between physical and genetic distances is 1560 kb/centimorgan, which compares with 1460 kb/centimorgan for the entire maize genome, and 217 kb/centimorgan for a 1-kb segment within the a1 locus. Therefore, these findings are consistent with the hypothesis that genes per se are preferred sites for meiotic recombination rather than the hypothesis that genes reside in large recombinationally active segments of the genome.

Alleles↗
PubMed1994

Postnatal development of voltage-sensitive Na+ channels in rat brain.

Previous studies have shown that mammalian neuronal excitability increases with age, and this excitability may be related to development of Na+ channels. In addition, evidence suggests that Na+ channels are involved in the neuronal response to O2 deprivation. Because of this, we wished to examine the pharmacologic properties and neuroanatomical distribution of the Na+ channels in newborn brain and as a function of age. In this study, we used ligand-binding techniques and autoradiography with 3H-saxitoxin (STX) to investigate Na(+)-channel distribution in brains of rats at postnatal days 0, 3, 10, 21, 35, and 120. We found that (1) in each area examined, the Scatchard plots for STX binding were linear in both immature and mature brains in a ligand concentration range of 0.4-64 nM; the slopes, however, were different between areas or ages, with Kd values ranging between 1 and 5 nM; (2) STX-binding density was more than tenfold lower in the rostral brain and cerebellum at birth than in the adult and increased with age; (3) binding density in the newborn brainstem was higher than in other areas such as the cortex and cerebellum, which is opposite to the distribution in the adult; and (d) the brainstem had a different developing pattern with an early-peak density level (P10-21) and a lower adult level.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1994

Role of K+ channels in neuropeptide Y-induced vasoconstriction in rabbit cerebral basilar artery.

The role of K+ channels in the direct vasoconstrictive response induced by neuropeptide Y was investigated in isolated basilar arteries of rabbits and in vivo in rats. K+ channel openers, either BRL38227 or diazoxide, caused dose-dependent and complete relaxation of isolated arteries precontracted by neuropeptide Y. Exposure to both BRL38227 and diazoxide shifted the concentration-response curves for neuropeptide Y to the right without changing the maximal response. However, BRL38227 antagonized the angiotensin II-induced vasoconstriction noncompetitively. In vivo, the pressor responses produced by neuropeptide Y were significantly inhibited by pretreatment with BRL38227 in anesthetized rats. These results show that K+ channel openers antagonize neuropeptide Y-induced vasoconstriction in a competitive manner and suggest that blockade of K+ channels contributes, at least in part, to the direct vasoconstrictive effect of neuropeptide Y.

Animals↗
PubMed1994

Voltage-sensitive Na+ channels increase in number in newborn rat brain after in utero hypoxia.

The effect of chronic in utero hypoxia on voltage-sensitive Na+ channels in newborn rat brain was investigated by means of ligand binding and autoradiography with [3H]saxitoxin (STX, Na+ channel ligand). We found that: (a) binding properties were different between hypoxic and control brains with alinear Scatchard plots in hypoxic brain versus linear ones in the control; (b) STX binding density increased greatly in response to hypoxic stimulation; and (c) the hypoxia-induced increase in STX binding was heterogeneous in various brain areas. We conclude that chronic hypoxia in utero alters the expression of Na+ channels and induces an up-regulation of Na+ channel density as a function of brain area. This is the first report of this phenomenon and we believe that the increased Na+ channels may play an important role in the etiology of neurological disorders such as epilepsy.

Animals↗
PubMed1994

Alternative splicing of the NC1 domain of the human alpha 3(IV) collagen gene. Differential expression of mRNA transcripts that predict three protein variants with distinct carboxyl regions.

Three clones of NC1 of alpha 3(IV) collagen, named Q1, L5, and V, were isolated from human kidney; these predict three variant alpha 3(IV) NC1 domains of 232-, 60-, and 199-amino acid residues, respectively, with unique COOH-termini. The human collagen IV gene (COL4A3) was isolated and characterized, and it was shown that the cDNA variants arose from alternative splicing by deletion of exon 4 in L5 and deletion of exon 2 in V. The mRNA transcripts were differentially expressed in fetal and adult human kidney with Q1 the major species. Exon 4-L5 lacked 183 residues from the carboxyl terminus with a frameshift producing a unique 11-amino acid terminal peptide. In exon 2-V a frameshift resulted in a unique V carboxyl terminus of 53 novel peptides with a new glycosylation site. The size of recombinant proteins indicated the frameshifts and new stop codons were as predicted. The multiple forms of the alpha 3(IV) NC1 region may contribute to autoimmune glomerular disease and hereditary nephritis, in which this portion of the collagen IV molecule is thought to play an important role.

Adult↗