Biomedical subjects

J Xie

Publications and source records attributed to J Xie.

At least 127 records · Page 7Linked to original sources

PubMed1999

Human herpesvirus 8 in hematologic diseases.

Human herpesvirus type 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV) is a new member of the g-herpesvirus family. It is an unusual herpesvirus in that it carries a large number of genes that encode oncoproteins or cell signaling proteins. In addition to being the causative agent of both HIV-associated and non-HIV-associated Kaposi's sarcoma this DNA tumor virus has been implicated in the pathogenesis of several diseases. These include multiple myeloma (MM), Waldenstöm's macroglobulinemia (WM), multicentric Castleman's disease (MCD), body cavity-based lymphoma (BCBL), and various other conditions such as sarcoidosis and pemphigus. While the causative role of the viral infection is fairly certain in the development of BCBL and multicentric Castleman's disease, HHV-8 may act through a different mechanism to induce plasma cell malignancies. It has been suggested though the finding is still controversial - that infection of bone marrow stromal dendritic cells by HHV-8 might be a key factor in the etiology and pathogenesis of monoclonal gammopathies. The aim of this review is to provide a short introduction into the tumorigenic potential of HHV-8 as well as to detail the available data and possible mechanisms on the involvement of this virus in different hematologic diseases.

Bone Marrow↗

PubMed1999

Effect of nitric oxide synthesis inhibition on c-Fos expression in hippocampus and cerebral cortex following two forms of learning in rats: an immunohistochemistry study.

This study investigated the effect of NO on c-Fos expression using immunocytochemical techniques, following training in the one-trial passive avoidance response and Morris water maze tasks. Fos-like immunoreactive (FLI) neurons were examined in the hippocampus and cerebral cortex of rats in which intracerebroventricular (i.c.v.) injection of Nomega-nitro-L-arginine (NAME) was given 30 min before training in the experimental groups. The results showed that: (1) when compared with untreated rats or rats receiving i.c.v. saline injection, fos-like immunoreactive neurons were significantly increased in both brain regions following training in either task, and (2) preceding i.c.v. injections of NAME blocked both the formation of memory and the increased expression of c-Fos in both brain regions subjected to training on the two models. These results suggest that NO production may be a critical factor for the formation of memory and the enhanced c-Fos expression, and so might contribute to the long-term plasticity of synaptic organization in the two brain regions.

Animals↗

PubMed1999

Expression of the L-type Ca(2+) channel in AtT-20 cells is regulated by cyclic AMP.

Activation of adenylyl cyclase by corticotropin-releasing hormone (CRH) stimulates secretion of adrenocorticotropin (ACTH) in rat anterior pituitary corticotropes and in the murine AtT-20 cell line. The stimulation of secretion is mediated by cAMP and is largely dependent on Ca(2+) influx through voltage-gated L-type Ca(2+) channels. To investigate whether CRH and cAMP also increase expression of the L-type Ca(2+) channel in AtT-20 cells, an RNase protection assay was used to measure the alpha(1C) mRNA that encodes the pore-forming subunit of the L-type Ca(2+) channel. The alpha(1C) mRNA level was measured by autoradiographic densitometry and normalized to the beta-actin mRNA level in the same sample. The alpha(1C) mRNA was not changed by 24-hour treatment with CRH (10-500 nM). A 24-hour treatment with 1 mM 8Br-cAMP significantly increased the alpha(1C) mRNA by 40% over its control. The stimulatory effect was blocked by 2 microM actinomycin D and was, therefore, dependent on gene transcription. The measured half-life of the alpha(1C) mRNA, after inhibition of transcription, was 4.7 +/- 0.3 h in control and 5.2 +/- 0.6 h in the presence of 8Br-cAMP. Thus the 8Br-cAMP- induced increase in alpha(1C) mRNA could be due to an increase in alpha(1C) gene transcription or to a transcriptionally regulated increase in a protein that helps to stabilize alpha(1C) mRNA. Finally, to determine if the increased mRNA was followed by an increase in production of L-type Ca(2+) channels, the binding of [(3)H]PN200-110 to Ca(2+) channel proteins was assayed in AtT-20 membrane fragments. 8Br-cAMP increased [(3)H]PN200-110 binding sites by 32% (B(max) 36.0 +/- 1.2 fmol/mg protein in control vs. 47.4 +/- 3.2 fmol/mg protein in 8Br-cAMP-treated cells) but did not change the K(d). These studies show that both alpha(1C) mRNA and L-type Ca(2+) channel protein are increased in AtT-20 cells by cAMP.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1999

Cold stress and corticotropin-releasing hormone induced changes in messenger ribonucleic acid for the alpha(1)-subunit of the L-type Ca(2+) channel in the rat anterior pituitary and enriched populations of corticotropes.

In response to stress, adrenocorticotropin (ACTH) is secreted from anterior pituitary corticotropes. Corticotropin-releasing hormone (CRH) is a potent stimulator of ACTH secretion. The CRH stimulation of secretion is mediated by cAMP and is largely dependent on Ca(2+) influx through voltage-gated L-type Ca(2+) channels. This study was designed to investigate whether the expression of L-type Ca(2+) channels in the rat anterior pituitary and in corticotropes is regulated by acute stress and CRH. RNase protection assays were used to quantify alpha(1C) mRNA of the L-type Ca(2+) channel. The alpha(1C) mRNA levels from stressed rats increased by 31% in anterior pituitaries of rats after 30 min of exposure to cold stress. Neither 60 min cold stress nor 30 min restraint stress had an effect on alpha(1C) mRNA levels. When alpha(1C) mRNA was detected by in situ hybridization in a population of corticotropes enriched to 90%, 0.5 nM CRH (3 h) stimulated a 36% increase in the average area of label/cell and a 10% increase in the average density of label. Our results suggest that (1) the expression of alpha(1C) subunit mRNA of L-type Ca(2+) channels is increased in the rat anterior pituitary with a stress-specific response that might reflect an increase both in thyrotropes and corticotropes (both are known to be stimulated by cold stress), and (2) the CRH-mediated increase in alpha(1C) mRNA expression in individual rat corticotropes, in vitro, supports the hypothesis that some of the increase in vivo is due to changes in corticotropes.

Adrenocorticotropic Hormone↗

PubMed1999

Prophylactic magnesium to decrease the arrhythmogenic potential of class III antiarrhythmic agents in a rabbit model.

We assessed the prophylactic effect of intravenous magnesium sulfate on the occurrence of torsades de pointes and early after-depolarizations, and on the QT interval (QTc) in an established rabbit model. Ten rabbits were given intravenous methoxamine to slow their heart rates. After 12 minutes five animals received a 60-mg/kg bolus and continuous infusion of magnesium 0.6 mg/kg/minute, and five received equivolume normal saline concurrently with the class III antiarrhythmic agent clofilium 5 mg/kg over 30 minutes. Electrocardiogram lead II and the monophasic action potential were recorded continuously throughout the experiment. The magnesium group experienced significantly less torsades de pointes and early after-depolarizations than the normal saline group (1/5 and 5/5 both parameters, respectively, p=0.048). There were no differences between groups in QT or QTc interval at baseline or at maximum QT or QTc prolongation. Magnesium decreases the occurrence of torsades de pointes without affecting the QT or QTc interval but does decrease the occurrence of early after-depolarizations. These findings must be validated in human studies.

Anesthesia↗

PubMed1999

A quantitative MR study of the hippocampal formation, the amygdala, and the temporal horn of the lateral ventricle in healthy subjects 40 to 90 years of age.

BACKGROUND AND PURPOSE: Several investigators have defined normal age-specific values for the medial temporal lobe structures in neurologically normal elderly subjects, but, to our knowledge, no one has reported those values for a large sample of healthy volunteers. The purpose of our study was to define normal age-specific values for the hippocampal formation, the amygdala, and the temporal horn of the lateral ventricle by age group, ranging from 40 to 90 years, in order to generate a guideline for the quantitative MR diagnosis and differential diagnosis for early Alzheimer disease. METHODS: MR-based volumetric measurements of the hippocampal formation, the amygdala, and the temporal horn, standardized by total intracranial volume, were obtained from oblique coronal and sagittal T1-weighted MR images in 619 healthy volunteers and two cadaveric specimens. RESULTS: Differences in standardized volumes of the hippocampal formation, the amygdala, and the temporal horn were significant among the 61- to 70-year-old, 71- to 80-year-old, and 81- to 90-year-old groups, and were not significant between the 40- to 50-year-old and 51- to 60-year-old groups. We found no significant differences in side or sex among the age groups for any of the structures. CONCLUSION: Differences in the mean value and in the 95% normal range of standardized volumes of the hippocampal formation, the amygdala, and the temporal horn correspond to differences in age among healthy subjects; therefore, age should be considered a factor in correlative research, especially in that involving patients in the early stages of Alzheimer disease.

Adult↗

PubMed1999

[The study of growth hormone on wound healing rate in adult burns].

OBJECTIVE: To determine the effects of rhGH on wound healing in adult burn patients. METHODS: 42 patients with burn wounds covering over 83% of total body surface area were enrolled in this placebo controlled prospective study. They were comparable in nutrient intake, TBSA, and full thickness burn area. For rhGH group patients rhGH subcutaneously was given in the dose of 0.2 U.kg-1 at 8 a.m. each morning for 14 days. The control group patients were given normal saline as placebo. Protein catabolism, immunocompetence, healing time of burn wounds and donor sites were assayed. RESULTS: 1. The patients in rhGH group had higher serum levels in albumin, transferrin, prealbumin and CD4 T-cells (P < 0.01). 2. The healing time of autologous skin grafting and donor site and the length of hospital stay were significantly shorter in rhGH group patients compared with control group. CONCLUSION: rhGH could enhance the wound healing rate, improve protein anabolism and reduce the length of hospital stay in severe burn patients.

Adolescent↗

PubMed1999

[Specific point-mutate p53 mini-gene transfectimg effects on biological behaviors of a human cancer cell line PG derived from human pulmonary giant carcinoma].

OBJECTIVES: To explore the suppressive effects of a murine genomic p53 minigene containing an Arg-->Leu substitution at its encoding amino acid 172 on biological behaviors of human carcinoma cell and evaluate its potential application in cancer gene therapy. METHODS: By LipofectaMINE and electraporation methods, this mutant p53 gene which lacked of exon 1 and intron 1 expression vector driven by CMV promoter was co-transfected with PCMVneo into PG cell in which dominant negative p53 pre-exists. A wild-type and another kind of genomic mutate-type p53 gene expression vector were transfected. The latter p53 gene encoding protein contained an Arg-->His substitution at the same position, and pBLuscript plasmid was used as control. All transfectants were screened by 500 micrograms/ml geneticin and identified by mouse specific p53 mRNA RT-PCR and Northern blot analysis. After transfection, the biological behavior changes were studied by colony formation and TUNEL test together with in-situ clone regression for chemosensitivity of anti-cancer drugs. RESULTS: The transfecting effects of this unusual p53 gene were surprisingly strong. They were more significant than those of the wild-type p53 and could suppress the formation of transgenic colonies and passage. The transgenic colonies were sensitive to be treated in adromycin and 5-Fu, and the gene transient expression could result in cell apoptosis. CONCLUSION: Codon 172 mutant (Arg-->Leu) p53 genomic DNA exhibited a strong suppressive transfecting effects on carcinoma cell, so it is a possible candidate to be used in cancer gene therapy.

Apoptosis↗

PubMed1999

[Analysis of the protein of Haemophilus influenzae].

OBJECTIVE: To understand Haemophilus influenzae special protein and to help for preparing Haemophilus influenzae Vaccine. METHODS: Proteins from isolates of Haemophilus influenzae were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). RESULTS: 23 isolates were from nasopharyngeal secretions of children with pneumonia and 33 from pharyx swab of healthy children. Conventional tests showed that 79% of fifty-six strains of Haemophilus influenzae were non-serotypable and all belonged to one of eight biotypes. The common biotypes were II (48%). All strains contained more than 10 proteins with molecular weights of 96,000, 86,000, 55,000, 51,000, 46,000, 40,000, 39,000, 31,000, 29,000, 25,000, and 16,000. Among them, three were major proteins (31,000, 51,000 and 96,000) and different proteins were mainly between peptide 31,000 and 51,000. A possible association between biotype and protein was unclear. CONCLUSION: Analysis of protein of Haemophilus influenzae is helpful for epidemiological study of non-serotypable Haemophilus influenzae and making Haemophilus influenzae vaccine.

Bacterial Proteins↗

PubMed1999

[The role of the leukocytes in pathogenesis of secondary brain injury].

The levels of leukocyte count, neutrophil number, leukocyte adhesiveness, leukocyte releasing oxygen-free radical (O2.-) after phagocytosing bacteria and serum lipid peroxide MDA were determined in the peripheral blood of 40 patients with acute head injury within 48 hours and 22 normal adults. These levels of patients were significantly higher than those of the controls (P < 0.05), and increased with the severity of craniocerebral injury elevation. The leukocyte count and neutrophil number of those patients who died were significantly higher than these of those survived patients (P < 0.05). It suggested that leukocytes aggravated the secondary brain injury after craniocerebral injury by increasing of leukocyte adhesiveness, and generating and releasing oxygen-free radical, and measurement of leukocyte count and neutrophil number in the peripheral blood could evaluate the prognosis of the patient with craniocerebral injury.

Adolescent↗

PubMed1999

[Determination of TNF-alpha and endotoxemia in patients with chronic liver diseases].

The incidence of endotoxemia in 153 patients with different liver diseases was determined by Limulus Lysaite Test(LLT). Comparative studies were carried out on the levels of tumour necrosis factor-alpha(TNF-alpha) between positive and negative endotoxemia in patients suffering from chronic liver diseases. At the same time, 58 patients of positive endotoxemia were divided into two groups--bifidobiogen group (38 cases) and control group(20 cases). The patients in bifidobiogen group were treated mainly with daily administration of bifidobiogen for 1 month besides general liver--protection therapy and the bifidobiogen was not given to the control group. The results showed that: 1. Incidence of endotoxemia in 153 patients suffering from various types of liver diseases was 65.36%; the highest rate was found in the patients with severe hepatitis; 2. The TNF-alpha level was obviously increased in the patients of positive endotoxemia; 3. The total efficacy in bifidobiogen group was significantly higher than that in control group. The data suggest that chronic liver diseases are generally complicated with endotoxemia, and TNF-alpha plays an important role in the pathogenesis of endotoxemia. The serum endotoxin level may be reduced after the treatment with bifidobiogen.

Adult↗

PubMed1999

[Study on cytotoxicity to leukemia cell and enhancement of immunologic functions of jiexinkang].

Cytotoxicity to leukemia cell and enhancement of immunologic functions of jiexinkang (JXK, traditional Chinese medicine) were observed in 34 cases of leukemia in vitro. The results showed that the leukemia cytotoxicity in the group of vincristine combined with JXK was significantly higher than that in vincristine alone. It was also found among all the observed cases that 20 refractory or recurred patients resistant to vincristine showed an obvious intention of the anti-toxicity efficiency when JXK was added. Jiexinkang alone had anti-leukemia cell effect, too. We explored JXK effects on immunologic functions in mice, and found that IFNr and NK activities of normal and experimental model mice were significantly higher than those of control group(P < 0.01). The results indicate that JXK has an effect of anti-leukemia cell and may improve the cell-immunologic functions.

Adjuvants, Immunologic↗

PubMed1999

[Correlative study on the level of serum type IV collagen, laminin and the diameters of portal veins in patients with viral hepatitis].

The contents of serum Type IV collagen and laminin were detected by radioimmunoassay and the diameters of portal veins were measured by B-mode ultrasound in 102 patients with different type of viral hepatitis. The results show that an increase of levels of Type IV collagen and laminin was found in patients with chronic severe hepatitis and fulminant hepatitis. The levels of Type IV collagen and laminin were obviously increased in the patients who have the diameter of portal vein > or = 12 mm compared with the patients who have the diameter of protal < 12 mm. There was a positive correlation between the levels of Type IV collagen, laminin and the diameters of portal vein.

Adolescent↗

PubMed1999

[Protective effects of ischemic preconditioning on ischemia reperfusion injuries of kidney: experimental studies].

We studied the serum levels of SOD and creatinine(Cr) of venous blood and changes in renal tissue structures under electromicroscope in the ischemia referfusion(I/R), the ischemic preconditioning(PC1, PC2, PC3), and the control groups in rabbits. The results were that the serum levels of SOD and Cr in the I/R group were obviously higher than that in the PC and control groups after one-hour ischemia and one-hour reperfusion(P < 0.001). There were no significant difference in Cr levels between the PC2 and control groups; there were significant degenerate and necrotic changes under the electromicroscope in renal tissues in the I/R group, but there were no significant change in the PC and control groups. The results suggest that PC plays a role in protecting the kidney from injury induced by ischemia and reperfusion.

Animals↗

PubMed1999

[The study of vapor-liquid equilibria for polymer/solvents by using gas-liquid chromatography].

The infinite dilution weight fraction activity coefficient, omega 1 infinity, and Flory-Huggins interaction parameter, chi, have been determined for systems of polydimethylsiloxane (PDMS)/solvents and polymethyl-methacrylate (PMMA)/solvents by using gas chromatography from 58 degrees C to 180 degrees C. The solvents include styrene, acetone, ethyl ether, methanol, ethanol, acetic acid, trichloromethane, tetrahydrofuran and ethyl acetate in PDMS/solvent systems and n-hexane, n-heptane, cyclohexane, benzene, toluene, ethyl benzene, styrene, acetone, ethyl ether, methanol, ethanol, methyl methacrylate(MMA), trichloromethane, tetrahydrofuran and ethyl acetate in the PMMA/solvent systems. The results showed that omega 1 infinity and chi were decreased with the increase of temperature in the range from 58 degrees C to 180 degrees C. The study showed that UNIFAC and UNIFAC-FV models could not all be used to estimate omega 1 infinity of the solvents in PMMA/solvent systems. Therefore, UNIFAC and UNIFAC-FV models must be corrected or other models must be used.

Chromatography, Gas↗

PubMed1999

[Industrial scale-up of continuous ethanol fermentation using yeast flocs].

Inducing yeast cells to self-flocculate as a cell immobilization method, an industrial scale-up plant composed of 4 air-lift suspended-bed bioreactors in parallel and with a total volume of 400 m3 was established and operated. During a more than 6 months continuous operation, the effluent contained ethanol of 70-80 g/L and residual sugar less than 5 g/L and the ethanol productivity of 7-8 g/L.h-1 was achieved.

Bioreactors↗

PubMed1998

Genomic structure and promoter sequence of the insulin-dependent diabetes mellitus autoantigen, IA-2 (PTPRN).

IA-2 is a transmembrane protein tyrosine phosphatase, expressed in neuroendocrine cells, and a major autoantigen in insulin-dependent diabetes mellitus. In the present study we elucidated the structure of the IA-2 gene (HGMW-approved symbol PTPRN) and its promoter sequence. A 40-kb genomic clone covering the whole IA-2 coding sequence and 4 kb proximal 5'-upstream sequence was isolated and mapped. The IA-2 gene encompasses approximately 20 kb with 23 exons ranging from 34 bp to more than 650 bp. The extracellular domain is encoded by exons 1-12, the transmembrane region by exon 13, and the intracellular domain by exons 14-23. The transcriptional start site(s) of the IA-2 gene was mapped by 5' rapid amplification of cDNA ends to 97 bp upstream of the translational start site. A 3-kb 5'-upstream region was sequenced, revealing a GC-rich region and TATA-less sequence containing several potential transcription-regulating sites (i.e., Sp1, CREB, GATA-1, and MZF). Functional promoter activity was confirmed by transient transfection of U87MG cells with deletion mutants linked to a luciferase reporter gene.

Autoantibodies↗

PubMed1998

Pharmacological characterisation of dopamine overflow in the striatum of the normal and MPTP-treated common marmoset, studied in vivo using fast cyclic voltammetry, nomifensine and sulpiride.

The in vivo measurement of electrically-evoked dopamine overflow was measured for the first time in the striatum of control and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated common marmosets using fast cyclic voltammetry at untreated carbon-fibre microelectrodes, (7 microm, o.d.). The identity of dopamine was confirmed using electrochemical, pharmacological and histological criteria and complied with rat data from earlier studies. Dopamine overflow depended on the intensity, number of pulses, and frequency of the applied stimuli. Maximum dopamine overflow occurred using 1.0-2.0 mA, 200 micros pulse width, 150-200 pulses at 80-120 Hz stimulation of the medial forebrain bundle. Evoked dopamine overflow in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated marmosets showed a similar electrochemical and pharmacological profile compared to healthy controls, albeit the concentration detected was significantly reduced. The catecholamine uptake blocker, nomifensine, significantly increased the dopamine signal in control marmosets. However, in contrast, nomifensine had no significant effect on evoked dopamine overflow in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated marmosets. Apart from demonstrating that fast cyclic voltammetry with electrical stimulation can be reliably used to monitor dopamine overflow within the primate brain, our results describe for the first time the technical prerequisites for the fast cyclic voltammetric technique in the non-human primate brain.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗