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Biomedical subjects

W Liu

Publications and source records attributed to W Liu.

At least 667 records · Page 37Linked to original sources
PubMed1997

Study on immunoregulation by interleukin-1 receptor antagonist in NZB/W F mice.

The immunoregulating effect of Interleukin-1-receptor antagonist (IL-1ra) in lupus-like NZB/W F1 mice was investigated to find possible approach to prevent lupus nephritis. 12 female NZB/W F1 mice of 13 weeks were randomly divided into 2 groups. Each mouse in the treated group was intraperitoneally injected with IL-1ra once every 2 weeks for 3 times at the dosage of 100 micrograms each time, while the control group was given injection of 0.1 ml normal saline. All the mice were killed at the age of 9 months and the immunologic function was examined. Results showed that this dosage could not completely prevent the development of lupus nephritis, but the renal damage was alleviated and the urine protein was decreased. Moreover, it could improve the immunofunction by significantly reducing the levels of serum IL-1 and obviously increase the activities of NK cells and IL-2 induced by ConA in mononuclear cells of spleen. There was no significant difference in the levels of serum IL-6 and TNF-alpha between the treated group and control group. It is concluded that IL-1ra has certain regulatory effect on the immunologic function of lupus-like NZB/W F1 mice.

Animals↗
PubMed1997

Measurement and clinical significance of endothelin in neonatal urine.

The present study was undertaken to figure out the source of urinary endothelin (ET) and the clinical significance of its possible variations. Urinary ET levels were measured by radioimmunoassay (RIA) in 17 healthy newborns and 20 asphyxiated neonates on days 1, 3, 7 after birth. Plasma ET concentrations of healthy premature infants on day 7 and urinary ET levels in 10 healthy children were also observed at the same time. Results showed that: (1) Urinary ET levels and ET excretion rates were higher than plasma ET in preterm infants on days 7 after birth; (2) Both in preterm and full term infants, urinary ET concentrations fell from the 1st day to the 7th day after birth, ET excretion rates elevated markedly at the end of the 1st week, and they were significantly higher than that of children; (3) Urinary ET levels of asphyxiated group on days 1 and 3 were much higher than those of healthy neonates, and positively correlated with the severity of the illness and urinary NAG. We conclude that: (1) urinary ET mainly comes from the production in renal cells; (2) ET levels in healthy neonatal urine reflect the maturity of kidney; (3) measurement of urinary ET levels in asphyxiated neonates is helpful to judge the degree and to evaluate the prognosis of renal injury.

Acute Kidney Injury↗
PubMed1997

Effect of asphyxia on urinary epidermal growth factor levels in newborns.

Urinary epidermal growth factor (EGF) excretion in normal newborn as well as neonates with asphyxia was investigated by using radioimmunoassay, and serum creatinine (Scr) levels determined at the same time. The results showed that in severe asphyxia group the ratio of urinary EGF to urinary creatinine (Cr) (EGF/Cr), an index reflecting EGF excretion, was decreased on the first day (P < 0.05) and reached the lowest level on the third day (P < 0.01). However, EGF/Cr values were decreased only on the third day in neonates with mild asphyxia (P < 0.05). On the seventh day, EGF/Cr values of neonates with asphyxia rose to normal. There were a negative correlation between urinary EGF/Cr and Scr. It is suggested that EGF may play a role in the repair of acute renal injury after asphyxia and the detection of urinary EGF concentration is useful in the judgment of severity of renal injury and in the evaluation of the recovery of renal tubule after injury.

Acute Kidney Injury↗
PubMed1997

Load assessment of the static posture and weight holding in terms of pulmonary ventilation and heart rate.

The aim of this study was to explore appropriate index for load evaluation by analyzing the changes of pulmonary ventilation (VE) and heart rate (HR) in 35 student volunteers under the condition of static posture and weight holding. Each subject was asked to perform 7 kinds of static postures and 2 kinds of weight holdings. The HR was continuously measured by a remote detecting device. VE was recorded by a ventimeter for an average of 5 min. The results showed that HR was positively correlated to VE under static activities (r = 0.89), which suggested that VE as well as HR could to some degrees reflect the static load. It was better to use VE to indicate the load of weight holdings than to use HR, which, on the other hand, was more sensible in reflection of the posture load. It is better to use relative value of both of VE and HR to reflect the static load. In addition, arm-overheaded posture increase HR more significantly than any other activities.

Adult↗
PubMed1997

Study on the protective effects of compound blood-activating soup on bone marrow hematopoietic cells in acute radiation injured mice.

After irradiation with 8 Gy 60Co gamma-ray, mice were immediately given intraperitoneal injection of 200 mg 100% compound blood-activating soup twice a day. On the 3rd and 7th day, the P53 gene expression of bone marrow hematopoietic cells in Chinese drug group was found to be higher than that in normal group, and it was also significantly higher than that in control group. The expression level of GADD153 gene which was not expressed in normal group was much lower in Chinese drug group than that in control group. On the 7th day after irradiation, the P53 and GADD153 gene expression levels of splenic mononuclear cells were consistent with those of bone marrow hematopoietic cells both in Chinese drug group and control group. On the 3rd and 7th day, the bone marrow hematopoietic tissue volume in Chinese drug group was higher than that in control group, with no difference found between the two groups. While on the 14th day, the difference became significant (P < 0.01). The results showed that commonly used blood-activating and stasis-eliminating drugs may strengthen the viability of hematopoietic cells and promote the rehabilitation of hematopoiesis by inducing wt-P53 expression to block the bone marrow hematopoietic cells in G1 phase, during which DNA could be repaired.

Animals↗
PubMed1997

Study on oxygen supply and protection of bone marrow in acute radiation injured mice.

After irradiated by 8 Gy 60Co gamma-ray, mice were intraperitoneally injected immediately with 0.2 ml 100% compound blood-activating soup twice a day for 10 days. The in situ ulnar bone marrow partial pressure of oxygen (PbO2) was determined in vivo before, during and after irradiation respectively. The bone marrow sections in the same part were observed. Our results showed that the normal murine ulnar PbO2 was 12.72 +/- 1.05 kPa. During irradiation, the level of PbO2 decreased to 10.78 +/- 1.17 kPa (P < 0.001). And 3 days after irradiation, PbO2 decreased to 9.75 +/- 0.52 kPa, suggesting that the commonly used "blood-activating and stasis-eliminating" Chinese drugs could promote the rehabilitation and proliferation of bone marrow microvessels in the acute radiation injured mice, expand their areas, increase the oxygen supply of bone marrow microenvironment, thereby leading to PbO2 much higher increase than that of control group. It is also helpful in the proliferation and rehabilitation of hematopoietic cells.

Animals↗
PubMed1997

Binaural and commissural organization of the primary auditory cortex of the mustached bat.

In the mustached bat, the primary auditory cortex (AI) can be divided into three subdivisions: the Doppler-shifted constant-frequency processing (DSCF) area, and the anterior (AIa) and posterior (AIp) regions. The DSCF area is composed of two subdivisions: excitatory-excitatory (E-E) and inhibitory-excitatory (I-E). The E-E division is located in the ventral portion of the DSCF area and mainly consists of neurons excited bilaterally, while the I-E division is located in the dorsal portion and mainly consists of neurons which are inhibited by ipsilateral ear stimuli, but excited by contralateral ear stimuli. The E-E division is bilaterally connected by commissural fibers, while the I-E division is not. The AIa and AIp regions have neither E-E neurons nor commissural connections. In the AI of the cat, E-E and I-E neurons form alternating bands which are parallel to the frequency axis. E-E bands are bilaterally connected by commissural fibers, but I-E bands are not. The DSCF area shares a similar functional organization with the AI of the cat.

Acoustic Stimulation↗
PubMed1997

Developmental changes of the ultrarapid delayed rectifier K+ current in rat ventricular myocytes.

Recent studies have shown the presence of a 4-aminopyridine (4-AP) sensitive, ultrarapid delayed rectifier K+ current (IK,ur) in adult human atria, but an apparent absence of this current in adult human ventricles. The present experiment was designed to investigate the postnatal changes of IK,ur in rat ventricular myocytes. The presence of IK,ur was evaluated with the use of a low concentration of 4-AP (50 micro;M). In 3-day-old newborns, the channel activity of rapidly activating outward current was predominantly the transient outward current (Ito). IK,ur could be recorded in a small number of 3-day-old cells lacking Ito (16%). In 10-day-old and adult rat ventricular myocytes, almost all cells expressed Ito and its current density increased significantly with age. The fraction of cells expressing IK,ur dramatically decreased with age and no IK,ur-like component could be detected in the adult cells. These findings first demonstrate that the expression of IK,ur is regulated developmentally in mammalian ventricular myocytes.

4-Aminopyridine↗
PubMed1997

The gene for microfibril-associated protein-1 (MFAP1) is located several megabases centromeric to FBN1 and is not mutated in Marfan syndrome.

Linkage studies have mapped the Marfan syndrome (MFS) locus to chromosome region 15q15-q21 with no convincing evidence of genetic heterogeneity. The fibrillin-1 (FBN1) gene, located at 15q21.1, that encodes the major component of the defective microfibrils, has been identified as the gene for MFS. However, extensive mutation screening in many laboratories has detected FBN1 mutations in only a fraction of MFS probands studied, leading to the hypothesis that the missing mutations could involve another microfibril gene located in the same region. Recently, the gene for microfibril-associated protein-1 (MFAP1, also called AMP) has been isolated and mapped to the 15q15-q21 region that overlaps the location of the FBN1 gene. Here we report that the two loci are physically close, making MFAP1 an alternative positional candidate gene for MFS. We have carried out MFAP1 mutation screening and gene expression analysis in 48 probands with MFS or related phenotypes who were selected for this study because their fibroblast cultures synthesized fibrillin at normal levels. No MFAP1 mutations were identified, and transcription occurred equally from both alleles. We conclude that the MFAP1 locus is not a reservoir for the hidden MFS mutations.

Base Sequence↗
PubMed1997

The pathogenicity of the Pro1148Ala substitution in the FBN1 gene: causing or predisposing to Marfan syndrome and aortic aneurysm, or clinically innocent?

In individuals with the Marfan syndrome (MFS), mutations have been identified in the fibrillin-1 gene (FBN1) at 15q21.1. A proline-to-alanine change at position 1148 in exon 27 (Pro1148Ala) has been reported in probands with MFS, aortic aneurysm or Marfanoid-craniosynostosis. It was suggested that this mutation could be a risk factor for aortic dilatation, since it was rarely observed in control populations. To investigate further the pathogenicity of this substitution, we screened 416 unrelated control individuals by allele-specific oligonucleotide (ASO) hybridization. We found 16 individuals who carried the alanine allele (3.8%), 3 of whom were homozygous. Five were of Latin American and eight were of Asian extraction. We also screened 133 probands with MFS, aortic aneurysm or related connective tissue disorders and found 4 (3%) that were heterozygous for the 1148Ala allele. All positive results were confirmed by DNA sequencing. In 20 individuals with 1148Ala, we confirmed the association with the rarer A allele at the IVS27-5G-->A polymorphism. Our results suggest that the Pro1148Ala change is a polymorphism of ancient evolutionary origin that is more prevalent in Asian and Latin American than in Caucasian or African populations.

Alanine↗
PubMed1997

Effect of conjugated linoleic acid on body composition in mice.

The effects of conjugated linoleic acid (CLA) on body composition were investigated. ICR mice were fed a control diet containing 5.5% corn oil or a CLA-supplemented diet (5.0% corn oil plus 0.5% CLA). Mice fed CLA-supplemented diet exhibited 57% and 60% lower body fat and 5% and 14% increased lean body mass relative to controls (P < 0.05). Total carnitine palmitoyltransferase activity was increased by dietary CLA supplementation in both fat pad and skeletal muscle; the differences were significant for fat pad of fed mice and skeletal muscle of fasted mice. In cultured 3T3-L1 adipocytes CLA treatment (1 x 10(-4)M) significantly reduced heparin-releasable lipoprotein lipase activity (-66%) and the intracellular concentrations of triacylglyceride (-8%) and glycerol (-15%), but significantly increased free glycerol in the culture medium (+22%) compared to control (P < 0.05). The effects of CLA on body composition appear to be due in part to reduced fat deposition and increased lipolysis in adipocytes, possibly coupled with enhanced fatty acid oxidation in both muscle cells and adipocytes.

3T3 Cells↗
PubMed1997

Role of granulocyte elastase in indomethacin-induced gastric mucosal lesion formation in rats.

To investigate whether granulocyte elastase may be involved in indomethacin-induced gastric mucosal injury, we examined the effects of the granulocyte elastase inhibitors ONO-5046 and L-658,758 on gastric mucosal lesion formation in rats given indomethacin. Both gastric mucosal lesion formation and gastric mucosal vascular damage were markedly attenuated in animals with leukocytopenia and in those given granulocyte elastase inhibitors. The administration of indomethacin significantly increased gastric myeloperoxidase activity, a measure of leukocyte accumulation, 3 hours after the administration of indomethacin compared with activity in animals receiving saline solution. The administration of ONO-5046 or L-658,758 significantly prevented this increase. Histologic examinations revealed submucosal edema and marked infiltration by leukocytes, as well as widespread necrosis with loss of surface epithelium. ONO-5046 and L-658,758 markedly prevented these histologic changes. Although cimetidine significantly prevented mucosal lesion formation, it did not inhibit either granulocyte elastase release from activated neutrophils in vitro or gastric accumulation of leukocytes in vivo. These results suggest that granulocyte elastase as well as gastric acid may play an important role in the pathologic process by which indomethacin induces gastric mucosal lesions.

Animals↗
PubMed1997

Regulation of vascular endothelial growth factor expression in human colon carcinoma cells by activity of src kinase.

BACKGROUND: The c-src protooncogene encodes a protein tyrosine kinase, pp60c-src, that is a mediator in many signal transduction pathways. One pathway in which pp60c-src protein tyrosine kinase activity is implicated involves regulation of vascular endothelial growth factor (VEGF), an angiogenic factor important to neovascularization of growing tumors. Recently we demonstrated that decreased activity of pp60c-src in colon tumor cells contributes to decreased expression of VEGF. This study examined the relationship between pp60c-src activation, cell density, and VEGF production in a colon tumor cell line. METHODS: Parental HT-29 colon adenocarcinoma cells and stable subclones created by transfection with c-src antisense and sense (control) expression vectors were plated under sparse (2 x 10(4) cells/cm2) and confluent (20 x 10(4) cells/cm2) conditions and grown for 36 hours. Protein and RNA were extracted from cells to determine pp60c-src levels, c-Src tyrosine kinase activity, and VEGF mRNA expression. RESULTS: The pp60c-src kinase activity of HT-29 cells and control sense-transfected clones grown under confluent conditions was increased threefold to fivefold compared with cells grown under sparse conditions. In contrast, the ability of confluent culture conditions to increase pp60c-src activity was blunted in antisense transfectants. By regression analysis, VEGF expression was found to vary directly with pp60c-src levels (r2 = 0.886). CONCLUSIONS: Cell density contributes to the regulation of c-src kinase activity and VEGF expression in HT-29 cells. When the steady-state level of pp60c-src is reduced in antisense transfectants, not only is the steady-state level of VEGF reduced, but the ability of confluence to stimulate pp60c-src activity and VEGF production is too. These data suggest that c-src may be an intermediary of both constitutive and inducible pathways for VEGF production in colon tumor cells.

Adenocarcinoma↗
PubMed1997

Human parvovirus B19 in bone marrows from adults with acquired immunodeficiency syndrome: a comparative study using in situ hybridization and immunohistochemistry.

Human parvovirus B19, which infects and lyses erythroid precursors, can cause severe anemia in patients with immunodeficiency. The incidence of parvovirus infection in adult acquired immunodeficiency syndrome (AIDS) patients is unknown. Eighty-one archival formalin-fixed, paraffin-embedded (FFPE) bone marrow biopsies from 73 AIDS adults were immunostained with monoclonal R92F6 against B19 VP1 and VP2 capsid proteins using streptavidin peroxidase and streptavidin alkaline phosphatase techniques. In addition, the same tissues were hybridized in situ with a digoxigenin-labeled parvovirus B19 DNA probe. Five FFPE bone marrows, from 3 HIV-negative patients with positive immunoglobulin M (IgM) serology for parvovirus B19, and 1 parvovirus B19-infected fetal liver were positive controls. By immunoperoxidase, all tissues were negative with R92F6 except the fetal liver, which exhibited strong positivity predominantly in viral inclusions. With immunoalkaline phosphatase, all positive controls were immunoreactive with R92F6; however, the AIDS marrows were negative. With in situ hybridization (ISH), all positive controls and 7 of 81 (8.6%) of AIDS marrows were positive for B19 parvovirus DNA. We conclude that ISH is more sensitive than R92F6 immunohistochemistry in parvovirus B19 detection. A small but significant number of bone marrows from AIDS adults shows evidence of human parvovirus B19 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Inhibition of benzo[a]pyrene-induced mouse forestomach neoplasia and reduction of H2O2 concentration in human polymorphonuclear leucocytes by flavour components of Japanese-style fermented soy sauce.

Previously it was reported that 4-hydroxy-2 (or 5)-ethyl-5 (or 2)-methyl-3(2H)-furanone (HEMF), a characteristic flavour component of Japanese-style fermented soy sauce that exhibits antioxidant activity, inhibits benzo[a]pyrene-induced forestomach neoplasia in mice. The antioxidant and anticarcinogenic activities of other structurally similar soy sauce flavour components are now reported. 4-Hydroxy-5-methyl-3(2H)-furanone (HMF) and 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) were found to be antioxidants. In particular, HMF and HDMF (as well as HEMF) reduced hydrogen peroxide concentration in human polymorphonuclear leucocytes stimulated by arachidonic acid or 12-O-tetradecanoylphorbol-13-acetate. HMF and HDMF were administered individually in semipurified diet to female ICR mice previously treated with benzo[a]pyrene (1.5 mg/wk, orally for 4 wk) to initiate forestomach neoplasia. The mice were killed at 30 wk of age. Both furanones reduced forestomach neoplasms, with HDMF exhibiting more potency. The data indicate that HDMF and HMF, like HEMF, inhibit carcinogenesis in this system by acting at the post-initiation stage.

Animals↗
PubMed1997

Atypical antipsychotics block the excitatory effects of serotonin in septohippocampal neurons in the rat.

We recently reported that serotonin excites a subpopulation of GABAergic neurons in the rat medial septum/diagonal band of Broca complex via multiple serotonin receptors, including the serotonin2A subtype. Since a subpopulation of medial septum/diagonal band GABAergic neurons projects to the hippocampus, in the present study we tested the effect of serotonin on antidromically-activated septohippocampal neurons using extracellular recordings. Bath-applied serotonin had an excitatory effect in a majority of septohippocampal neurons; serotonin-excited septohippocampal neurons had a mean conduction velocity -1.63 +/- 0.07 m/s (n=101). Pharmacologically, MDL 100,907, a selective serotonin2A antagonist blocked the excitatory effect of serotonin in 78% of septohippocampal neurons tested, with a mean pA2 of 8.51 +/- 0.12 (n=22). Additionally, the atypical antipsychotics risperidone and clozapine but not the typical antipsychotic haloperidol, blocked the excitatory effects of serotonin at clinically relevant concentrations. The pA2 values of 8.84 +/- 0.11, 6.57 +/- 0.13 and 5.94 +/- 0.27 for risperidone, clozapine and haloperidol, respectively, obtained in the present study, give a rank order of potency risperidone (1.6 nM) clozapine (269 nM) haloperidol (1.1 microM) which corresponds to that reported in binding studies. Additionally, in whole-cell patch-clamp recordings, risperidone (10 nM) blocked serotonin-induced increase in GABAergic synaptic currents. In conclusion, serotonin excites septohippocampal neurons primarily via the serotonin2A receptor and atypical antipsychotics block this excitation at clinically relevant concentrations.

Animals↗
PubMed1997

Tenascin-X deficiency is associated with Ehlers-Danlos syndrome.

The tenascins are a family of large extracellular matrix proteins with at least three members: tenascin-X (TNX), tenascin-C (TNC, or cytotactin) and tenascin-R (TN-R, or restrictin). Although the tenascins have been implicated in a number of important cellular processes, no function has been clearly established for any tenascin. We describe a new contiguous-gene syndrome, involving the CYP21B and TNX genes, that results in 21-hydroxylase deficiency and a connective-tissue disorder consisting of skin and joint hyperextensibility, vascular fragility and poor wound healing. The connective tissue findings are typical of the Ehlers-Danlos syndrome (EDS). The abundant expression of TNX in connective tissues is consistent with a role in EDS, and our patient's skin fibroblasts do not synthesize TNX protein in vitro or in vivo. His paternal allele carries a novel deletion arising from recombination between TNX and its partial duplicate gene, XA, which precludes TNX synthesis. Absence of TNX mRNA and protein in the proband, mapping of the TNX gene and HLA typing of this family suggest recessive inheritance of TNX deficiency and connective-tissue disease. Although the precise role of TNX in the pathogenesis of EDS is uncertain, this patient's findings suggest a unique and essential role for TNX in connective-tissue structure and function.

Adult↗