PubMed Health⌕ Search

Biomedical subjects

X L Liu

Publications and source records attributed to X L Liu.

At least 19 recordsLinked to original sources
PubMed2006

Poverty and the economic effects of TB in rural China.

OBJECTIVE: To investigate the economic effects of illness on individual tuberculosis (TB) cases in rural China and to use a case-control study to show a strong TB-poverty link. SETTING: In 2002-2004 we studied 160 new smear-positive pulmonary tuberculosis (PTB) cases and 320 age- and sex-matched controls living in neighbouring houses in four rural counties of Henan Province. DESIGN: Cases and controls were interviewed 1-3 months after patients were diagnosed. We used matched multivariate logistic regression to compare cases with controls for poverty status using household income, household assets and relative wealth within the village. We conducted follow-up interviews of patients 10-12 months later to assess economic effects by collecting data on treatment costs, income losses, coping strategies and treatment completion. RESULTS: Poverty is strongly associated with TB incidence even after controlling for smoking and other risk factors. Excluding income losses, direct out-of-pocket treatment costs (medical and non-medical) accounted for 55.5% of average annual household income, and most TB cases fell into heavy debt. The DOTS cure rate was 91%. When DOTS was incomplete or not done, mortality was high. CONCLUSIONS: Poverty is both a cause and a devastating outcome of TB. Ongoing poverty reduction schemes in China must also include reducing TB.

Adult↗
PubMed2005

Effects of artificial liver support system on patients with acute or chronic liver failure.

AIMS: Acute on chronic liver failure (AoCLF) is associated with a high mortality rate. Artificial liver support system (ALSS) is useful to bridge patients with liver failure to liver transplantation or to regenerate their own livers. The aims of this prospective study were to investigate the effects of ALSS on clinical manifestations, liver function, and 30-day survival to probe the factors related to mortality in patients with AoCLF. METHODS: In this study, 338 enrolled patients with AoCLF who received ALSS treatment for 1 to 8 sessions, were compared with 312 patients treated with conventional medications. RESULTS: Clinical manifestations and liver functions were significantly improved, namely, decreased levels of serum transaminases, total bilirubin, and bile acid, as well as increased levels of serum albumin following ALSS treatment. The 30-day survival rates of the patients who received ALSS versus controls were 47.9% versus 34.6%, respectively (P = .01). The MELD score and the stage of hepatic encephalopathy were highly associated with mortality (P < .001), but the sessions of ALSS showed a positive relation to the 30-day survival (P < .05). CONCLUSIONS: ALSS appears to be efficacious and safe for the treatment of patients with AoCLF. Both model for end-stage liver disease (MELD) score and hepatic encephalopathy are useful to predict the mortality of patients.

Adolescent↗
PubMed2005

Oestrogen influence on myogenic satellite cells following downhill running in male rats: a preliminary study.

AIM: This study examined the effect of oestrogen supplementation in rats on myogenic satellite cell quantities in type I and II muscles following eccentric exercise. METHODS: Gonad intact adult male rats divided into four groups, oestrogen supplemented (25 mg oestrogen pellet) control (EC), oestrogen supplemented, exercised (EE), sham (no oestrogen) control (SC) and sham, exercised (SE). After 1 week of oestrogen exposure the EE and SE animals performed 90 min of intermittent downhill running (5 min running/2 min rest @-13.5 degrees incline and 17 m min(-1) speed). Seventy-two hours later exercised (EE and SE) and control (EC and SC) animals were killed and blood samples taken and soleus and white (superficial) vastus muscles surgically removed. Histochemical sections of soleus and white vastus muscles were examined for myogenic satellite cell content by use of Pax7 antibody and for neutrophil content by use of haematoxylin and eosin (H and E) staining procedures. RESULTS: Downhill running resulted in significant elevations in satellite cells and neutrophils detected in both soleus and white vastus muscle samples (P < 0.01). Interestingly, oestrogen supplementation resulted in significantly greater (P < 0.01) post-exercise elevations in satellite cells detected in both soleus and white vastus muscle samples compared with sham (no oestrogen) rats. Increases in neutrophils were significantly (P < 0.05) attenuated in oestrogen supplemented rats relative to sham in soleus but not in white vastus muscles. CONCLUSIONS: Oestrogen supplementation in male rats may have accentuated the 72 h post-downhill running increase in Pax7 detected myogenic satellite cell number in both soleus and white vastus muscles relative to unsupplemented rats. The mechanisms and physiological consequences of this effect are yet to be determined.

Animals↗
PubMed2005

Chalcones: an update on cytotoxic and chemoprotective properties.

Chalcone is a unique template that is associated with several biological activities. In this review, an update of the cytotoxic and chemoprotective activities of chalcones is provided. Cytotoxicity against tumour cell lines may be the result of disruption of the cell cycle, inhibition of angiogenesis, interference with p53-MDM2 interaction, mitochondrial uncoupling or induction of apoptosis. Structural requirements for cytotoxic activity vary according to the mechanisms of action. For anti-mitotic activity, the presence of methoxy substituents, alpha-methylation of the enone moiety and the presence of 2' oxygenated substituents are favourable features. Conformational restraint of the chalcone template generally leads to a decrease in cytotoxic activity. Chemoprotection by chalcones may be a consequence of their antioxidant properties, mediated via inhibition or induction of metabolic enzymes, by an anti-invasive effect or a reduction in nitric oxide production. Hydroxyl and prenyl substituents are associated with antioxidant properties and induction of quinone reductase activities. The thiol reactivity of chalcones is likely to contribute to both cytotoxic and chemoprotective properties of these compounds.

Animals↗
PubMed2005

Electron microscopic studies on the occurrence of activated neutrophils in peripheral blood of children with acute leukemias.

Peripheral blood (PB) cells are examined to assess cellular maturity and the degree of bone marrow abnormality in children with acute leukemias. During the ultrastructural assessments of PB cells in these children, we noted a frequent occurrence of activated neutrophils. This phenomenon had not been reported previously. We here report for the first time the identification of activated neutrophils in PB of children with acute leukemias. To examine the impact of activated neutrophils, we compared two groups of children including 18 with acute lymphoblastic leukemia (ALL) and 7 with acute myelogenous leukemia (AML) by an ultrastructural leukocyte count method. Many cases (50%) showed more than 30% activated neutrophils per total neutrophil count in PB. Activated neutrophils were elongated or amoeboid-shaped cells ranging from 13-18 microns in greater diameter with a decreased number of granules in the cytoplasm. A significantly higher rate of activated neutrophils was observed in ALL as compared with AML (median: 42.97% vs. 10.64%). Non-leukemic hospitalized (n =3) and healthy (n = 3) control cases showed a median rate of 3.32% activated neutrophils in PB. These findings reveal that a significantly high rate of activated neutrophils occurs in PB of children with ALL which may be exploited in the diagnostic assessment of children with acute leukemias.

Child↗
PubMed2003

Isolation and characterization of viruses related to the SARS coronavirus from animals in southern China.

A novel coronavirus (SCoV) is the etiological agent of severe acute respiratory syndrome (SARS). SCoV-like viruses were isolated from Himalayan palm civets found in a live-animal market in Guangdong, China. Evidence of virus infection was also detected in other animals (including a raccoon dog, Nyctereutes procyonoides) and in humans working at the same market. All the animal isolates retain a 29-nucleotide sequence that is not found in most human isolates. The detection of SCoV-like viruses in small, live wild mammals in a retail market indicates a route of interspecies transmission, although the natural reservoir is not known.

Amino Acid Sequence↗
PubMed2003

Photodegradation of 17alpha-ethynylestradiol in aqueous solution exposed to a high-pressure mercury lamp (250 W).

The photodegradation of 17alpha-ethynylestradiol (EE(2)) induced by high-pressure mercury lamp (lambda> or =313, 250 W) in aqueous solution of EE(2) was investigated initially. The affecting factors on the photodegradation were studied and described in details, such as EE(2) initial concentration, Fe(3+), algae, exposure time, and so on. The concentration of EE(2) in distilled water was mainly determined using fluorescence spectrophotometer. The photodegradation of EE(2) in aqueous solution exposed to high-pressure mercury lamp was evident and could be accelerated by Fe(3+) or algae (e.g. Anabaena cylindrica) in general. With the algae concentration increasing, photodegradation rate increased. In this paper, the mechanism of photocatalytic degradation of EE(2) by Fe(3+) or algae is discussed primarily.

Anabaena↗
PubMed2003

Differences in cerebral reperfusion and oxidative injury after cardiac arrest in pigs.

BACKGROUND: An investigation of the free radical scavenger sodium 2-sulfophenyl-N-tert-butyl nitrone (S-PBN) and the weak vasodilatator Tris buffer mixture (TBM) on cerebral cortical blood flow (CCBF) and the jugular bulb concentration of two eicosanoids, indicators of oxidative stress and inflammation, was undertaken in 30 anaesthetized piglets during cardiopulmonary resuscitation (CPR) and after restoration of spontaneous circulation (ROSC). METHODS: Thirty animals were subjected to 8 min of untreated circulatory arrest followed by 8 min of closed-chest CPR. During CPR, the animals were randomized to receive 60 mg/kg S-PBN, 1 mmol/kg TBM or 2 ml/kg normal saline (n = 10 in each group). Systemic haemodynamic variables, CCBF and jugular bulb plasma concentrations of 8-iso-PGF2alpha and 15-keto-dihydro-PGF2alpha were measured. RESULTS: The CCBF during reperfusion after ROSC was greater in the TBM group than in the S-PBN group, the regression coefficient between CCBF and mean arterial blood pressure being lower in the S-PBN group than in the TBM group. The jugular bulb plasma concentration of 8-iso-PGF2alpha during the first 30 min after ROSC was greater in the TBM group than in the S-PBN group. Administration of TBM after vasopressin did not attenuate the pressor effect of vasopressin. CONCLUSION: Administration of S-PBN during CPR results in less cerebral oxidative stress, possibly by promoting normal distribution of cerebral blood flow.

Animals↗
PubMed2002

Neurological outcome after experimental cardiopulmonary resuscitation: a result of delayed and potentially treatable neuronal injury?

BACKGROUND: In experimental cardiopulmonary resuscitation (CPR) aortic balloon occlusion, vasopressin, and hypertonic saline dextran administration improve cerebral blood flow. Free radical scavenger alpha-phenyl-N-tert-butyl-nitrone (PBN) and cyclosporine-A (CsA) alleviate neuronal damage after global ischemia. Combining these treatments, we investigated neurological outcome after experimental cardiac arrest. METHODS: : Thirty anesthetized piglets, randomly allocated into three groups, were subjected to 8 min of ventricular fibrillation followed by 5 min of closed-chest CPR. The combined treatment (CT) group received all the above-mentioned modalities; group B was treated with balloon occlusion and epinephrine; and group C had sham balloon occlusion with epinephrine. Indicators of oxidative stress (8-iso-PGF(2 alpha)), inflammation (15-keto-dihydro-PGF(2 alpha)), energy crisis (hypoxanthine and xanthine), and anoxia/hypoxia (lactate) were monitored in jugular bulb venous blood. Neurological outcome was evaluated 24 h after CPR. RESULTS: : Restoration of spontaneous circulation (ROSC) was more rapidly achieved and neurological outcome was significantly better in the CT group, although there was no difference in coronary perfusion pressure between groups. The jugular venous PCO2 and cerebral oxygen extraction ratio were lower in the CT group at 5-15 min after ROSC. Jugular venous 8-iso-PGF(2 alpha) and hypoxanthine after ROSC were correlated to 24 h neurological outcome CONCLUSIONS: : A combination of cerebral blood flow promoting measures and administration of alpha-phenyl-N-tert-butyl-nitrone and cyclosporine-A improved 24 h neurological outcome after 8 min of experimental normothermic cardiac arrest, indicating an ongoing neuronal injury in the reperfusion phase.

Angioplasty, Balloon, Coronary↗
PubMed2002

Endoplasmic reticulum Ca(2+) signaling and calpains mediate renal cell death.

The goal of the current study was to determine the roles of ATP content, endoplasmic reticulum (ER) Ca(2+) stores, cytosolic free Ca(2+) (Ca(2+)(f)) and calpain activity in the signaling of rabbit renal proximal tubular (RPT) cell death (oncosis). Increasing concentrations (0.3-10 microM) of the mitochondrial inhibitor antimycin A produced rapid ATP depletion that correlated to a rapid and sustained increase in Ca(2+)(f), but not phospholipase C activation. The ER Ca(2+)-ATPase inhibitors thapsigargin (5 microM) or cyclopiazonic acid (100 microM) alone produced similar but transient increases in Ca(2+)(f). Pretreatment with thapsigargin prevented antimycin A-induced increases in Ca(2+)(f) and antimycin A pretreatment prevented thapsigargin-induced increases in Ca(2+)(f). Calpain activity increased in conjunction with ER Ca(2+) release. Pretreatment, but not post-treatment, with thapsigargin or cyclopiazonic acid prevented antimycin A-induced cell death. These data demonstrate that extensive ATP depletion signals oncosis through ER Ca(2+) release, a sustained increase in Ca(2+)(f) and calpain activation. Depletion of ER Ca(2+) stores prior to toxicant exposure prevents increases in Ca(2+)(f) and oncosis.

Adenosine Triphosphate↗
PubMed2001

Activated Notch2 signaling inhibits differentiation of cerebellar granule neuron precursors by maintaining proliferation.

In the developing cerebellar cortex, granule neuron precursors (GNPs) proliferate and commence differentiation in a superficial zone, the external granule layer (EGL). The molecular basis of the transition from proliferating precursors to immature differentiating neurons remains unknown. Notch signaling is an evolutionarily conserved pathway regulating the differentiation of precursor cells of many lineages. Notch2 is specifically expressed in proliferating GNPs in the EGL. Treatment of GNPs with soluble Notch ligand Jagged1, or overexpression of activated Notch2 or its downstream target HES1, maintains precursor proliferation. The addition of GNP mitogens Jagged1 or Sonic Hedgehog (Shh) upregulates the expression of HES1, suggesting a role for HES1 in maintaining precursor proliferation.

Animals↗
PubMed2001

The protective effect of hepatocyte growth-promoting factor (pHGF) against hydrogen peroxide-induced acute lung injury in rats.

To examine the protective effect of hepatocyte growth-promoting factor (pHGF) in hydrogen peroxide (H(2)O(2))-induced acute lung injury in rats, we observed the pathological changes in lung tissue by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and by light and electron microscopy. We also measured the serum levels of lipid peroxide (LPO). At 6 to 24 h after H(2)O(2) injection, the level of LPO was significantly higher in the H(2)O(2) group than in the H(2)O(2) + pHGF-treated group. This finding indicated that pHGF protected against cell membrane damage in H2O2-induced acute lung injury. Positive TUNEL signals were found in capillary endothelial cells, alveolar epithelial cells, and inflammatory cells. In the H(2)O(2) + pHGF-treated group, TUNEL-positive signals were reduced compared with those in the H(2)O(2) group. This finding indicated that pHGF acts to suppress apoptosis. In the H(2)O(2) group, severe pulmonary edema was seen 3 h after H(2)O(2) injection, and at 24 h, severe atelectasis was seen. In the H(2)O(2) + pHGF-treated group, pulmonary edema was scarcely seen and severe atelectasis was not found. This finding indicated that pHGF acts to suppress both severe pulmonary edema and atelectasis. In the H(2)O(2) group, the formation of subendothelial blebs and disruption of endothelial cells was observed. Edema and disruption were seen in type I epithelial cells. In type II lung epithelial cells, mitochondria were swollen and microvilli had disappeared. In the H(2)O(2) + pHGF-treated group, the formation of subendothelial blebs was seen, but no severe subendothelial blebs were observed. Disruption of capillary endothelial cells and type I epithelial cells was not evident, nor was there damage to type II lung epithelial cells. These findings indicated that pHGF protects the progression of H(2)O(2)-induced acute lung injury, and showed that pHGF acts to stabilize the cell membrane in capillary endothelial cells and lung epithelial cells.

Animals↗
PubMed2001

Use of chemically extracted muscle grafts to repair extended nerve defects in rats.

Nerve regeneration, measured as axonal outgrowth, Schwann cell migration, macrophage invasion, and neovascularisation, was compared after repair of a 15 mm gap in rats' sciatic nerves using autologous muscle grafts made acellular either by freezing and thawing or by chemical extraction. Both extracted and freeze-thawed acellular muscle grafts could be used to bridge the defect. However, axons and Schwann cells, as shown by immunohistochemical staining for neurofilaments and S-100 protein, respectively, grew faster into the extracted muscle grafts than into the freeze-thawed acellular muscle grafts and somewhat more axons were observed in the former graft. There were no significant differences between the two graft types with respect to neovascularisation as showed by staining for endothelial alkaline phosphatase, and limited differences concerning invasion of macrophages (ED1 and ED2) as detected by immunocytochemistry. The results showed that chemically extracted muscle grafts could be used to bridge an extended nerve defect and that such grafts in some aspects were superior to freeze-thawed muscle grafts for extended gaps.

Alkaline Phosphatase↗
PubMed2001

ELF3 encodes a circadian clock-regulated nuclear protein that functions in an Arabidopsis PHYB signal transduction pathway.

Many aspects of plant development are regulated by photoreceptor function and the circadian clock. Loss-of-function mutations in the Arabidopsis EARLY FLOWERING 3 (ELF3) and PHYTOCHROME B (PHYB) genes cause early flowering and influence the activity of circadian clock-regulated processes. We demonstrate here that the relative abundance of the ELF3 protein, which is a novel nucleus-localized protein, displays circadian regulation that follows the pattern of circadian accumulation of ELF3 transcript. Furthermore, the ELF3 protein interacts with PHYB in the yeast two-hybrid assay and in vitro. Genetic analyses show that ELF3 requires PHYB function in early morphogenesis but not for the regulation of flowering time. This suggests that ELF3 is a component of a PHYB signaling complex that controls early events in plant development but that ELF3 and PHYB control flowering via independent signal transduction pathways.

Amino Acid Sequence↗
PubMed2001

ELF3 modulates resetting of the circadian clock in Arabidopsis.

The Arabidopsis early flowering 3 (elf3) mutation causes arrhythmic circadian output in continuous light, but there is some evidence of clock function in darkness. Here, we show conclusively that normal circadian function occurs with no alteration of period length in elf3 mutants in dark conditions and that the light-dependent arrhythmia observed in elf3 mutants is pleiotropic on multiple outputs normally expressed at different times of day. Plants overexpressing ELF3 have an increased period length in both constant blue and red light; furthermore, etiolated ELF3-overexpressing seedlings exhibit a decreased acute CAB2 response after a red light pulse, whereas the null mutant is hypersensitive to acute induction. This finding suggests that ELF3 negatively regulates light input to both the clock and its outputs. To determine whether ELF3's action is phase dependent, we examined clock resetting by using light pulses and constructed phase response curves. Absence of ELF3 activity causes a significant alteration of the phase response curve during the subjective night, and constitutive overexpression of ELF3 results in decreased sensitivity to the resetting stimulus, suggesting that ELF3 antagonizes light input to the clock during the night. The phase of ELF3 function correlates with its peak expression levels in the subjective night. ELF3 action, therefore, represents a mechanism by which the oscillator modulates light resetting.

Arabidopsis↗
PubMed2001

Effect of scopoletin on PC3 cell proliferation and apoptosis.

AIM: To investigate the effect of scopoletin on cell proliferation and apoptosis of PC3 cells. METHODS: Cell growth curve, MTT assay, and acid phosphatase activity (ACP) were used to determine cell proliferation. Coomassie brilliant blue assay was used to measure the content of protein in cells. Light microscope, transmission electronmicroscope, and fluorescence microscope were used to observe scopoletin-induced morphological changes. Apoptosis rate and cell cycle distribution were determined by flow cytometry. RESULTS: The IC50 of scopoletin for inhibiting PC3, PAA, and Hela cell proliferation was (157 +/- 25), (154 +/- 51), and (294 +/- 100) mg/L, respectively. Scopoletin induced a marked time- and concentration-dependent inhibition of PC3 cell proliferation. Scopoletin reduced the protein content and decreased the ACP level in PC3 cells in a concentration-dependent manner. Cells treated by scopoletin showed typical morphologic changes of apoptosis by light microscope, fluorescence microscope, and transmission electronmicroscope. Apoptosis rate was 0.3 %, 2.1 %, 9.3 % and 35 % for scopoletin 0, 100, 200, and 400 mg/L, respectively, and cells in G2 phase decreased markedly after being treated with scopoletin. CONCLUSION: Scopoletin inhibited PC3 proliferation by inducing apoptosis of PC3 cells.

Apoptosis↗
PubMed2001

[Sensitive and rapid analysis of nitrophenols and herbicides by capillary zone electrophoresis (CZE)].

11 Nitrophenols and some acidic herbicides have been separated by modified CZE. Good separation of such compounds can be achieved in less than 10 min by simply modifying the run buffer with organic solvents such as methanol, acetonitrile in a concentration of 40% (V/V). The limits of detection (LODs) for nitrophenols by UV-absorption at 215 nm were 0.5 mg/L-1.1 mg/L. Solid phase extraction was used to preconcentrate nitrophenols and some herbicides to reach an LOD at microgram/L levels. Typical samples have been analyzed.

Electrophoresis, Capillary↗