Biomedical subjects

H Li

Publications and source records attributed to H Li.

At least 397 records · Page 22Linked to original sources

PubMed2001

[Effect of unprepared and prepared "he zi" on contraction of isolated trachea smooth muscle in rabbits].

Isolated trachea smooth muscle in rabbits induced by Ach or KCl was adopted to study the effect of unprepared and prepared "He Zi". The results showed that unprepared "He Zi" couldn't affect the contraction of isolated trachea smooth muscle in rabbit induced by Ach or KCl, and that prepared "He Zi" couldn't affect the contraction of isolated trachea smooth muscle in rabbit induced by KCl. The results also showed that prepared "He Zi" could significantly inhibit the contraction induced by Ach. The inhibition effect may not be associated with cGMP, adrenergic receptor, and release of NO and prostaglandin, and was epithelium independent. Maybe the different content of tannic acid contributed to the different effect between unprepared and prepared "He Zi".

Acetylcholine↗

PubMed2001

Fibrinogen: a vascular risk factor, why? Contributing effect of oncostatin M on both fibrinogen biosynthesis by hepatocytes and participation in atherothrombotic risk related to modifications of endothelial cells.

Fibrinogen is a vascular risk factor. We suggest that it is a marker of cytokine secretion that simultaneously stimulates fibrinogen biosynthesis and vascular modifications responsible for atherothrombosis. Among these cytokines, oncostatin M (OSM) is the most potent cytokine for inducing fibrinogen biosynthesis by hepatocytes, and it could contribute to endothelial cell anomalies involved in the atherothrombotic process. Here we show that OSM acts (1) by inducing the secretion involved in invasion of the vessel wall by monocytes; (2) by inducing angiogenesis it promotes plaque destabilization, rupture, and consequently thrombosis; and (3) by decreasing fibrinolysis on macrovascular endothelial cells.

Arteriosclerosis↗

PubMed2001

[Effects of intestinal endotoxemia on the development of cirrhosis in rats].

OBJECTIVE: To explore the effect of endotoxin on the development of cirrhosis. METHODS: The cirrhosis model with intestinal endotoxemia was made by oral intake of 0.03% thioacetamide for four months to observe the effect of endotoxin on the hepatic collagen contents in both thioacetamide and thioacetamide + lipopolysaccharide groups and to detect the contents of tumor necrosis factor-alpha (TNF-alpha), endothelin-1 (ET-1), nitric oxide (NO), and malondialdehyde (MDA) in the plasma and the hepatic homogenate. RESULTS: The contents of TNF-alpha, ET-1, NO, and MDA in the plasma and the hepatic homogenate and the content of collagen in the hepatic tissue in the two groups were higher than those in the normal control group. CONCLUSIONS: Endotoxin can accelerate liver fibrosis and the formation of cirrhosis.

Animals↗

PubMed2001

[Purification and characterization of recombinant human interleukin 11 which expressed by Pichia pastoris].

This study first time report a method to purify the rhIL-11 which expressed by Pichia pastoris. rhIL-11 was secreted into the supernatant and collected by centrifugation. The purity of rhIL-11 reached 97% through the steps of ultrafiltration, SP Sepharose FF, Phenyl Sepharose HP and Sephadex G25. Analysis of SDS-PAGE, Western-blotting, IEF, RP-HPLC, Mass spectrometer, N and C terminus amino acid sequence and bioactivity was conducted. All the analysis results proved that the rhIL-11 expressed by Pichia pastoris was the same as Neumeg which was expressed in E. coli with fusion expression system. So it is possibly a cheaper and easier method to produce rhIL-11 for clinical use.

Fermentation↗

PubMed2001

[Causes and countermeasures about adverse reaction of traditional Chinese medicine].

The literatures about the adverse reaction (AR) of traditional Chinese medicine from 1915 to 1996 in China and some recent reports abroad were reviewed. The principal causes of the AR of traditional Chinese medicine were summarized and some corresponding preventive countermeasures were put forward. The principal causes of this problem were overdosage and drug abuse. The key problem to be solved is to adhere to "treatment according to syndrome differentiation" and the rational administration of traditional Chinese medicine.

Drugs, Chinese Herbal↗

PubMed2001

Effect of Cr(VI) exposure on sperm quality: human and animal studies.

The semen status of male workers occupationally exposed to hexavalent chromium(VI) was investigated. Sperm counts from exposed workers were 47.05+/-2.13 x 10(6)/ml and those from control group 88.96+/-3.40 x 10(6)/ml. Sperm motility decreased from 81.92+/-0.41% for the control group to 69.71+/-0.93% for the exposed workers. The levels of zinc, lactate dehydrogenase (LDH), and lactate dehydrogenase C4 isoenzyme (LDH-x) in seminal plasma for the exposed workers were 1.48+/-0.07 micromol/ml, 1.05+/-0.02 x 10(3) U, and 0.47+/-0.01 x 10(3) U, respectively, which were significantly lower than those of 5.72+/-0.15 micromol/ml, 1.49+/-0.02 x 10(3) U, and 0.78+/-0.15 x 10(3) U for the control group, respectively. Follicle stimulating hormone (FSH) (7.34+/-0.34 x 10(-3) IU/ml) in serum from the exposed workers was significantly higher than that (2.41+/-0.08 x 10(-3) IU/ml) from the control group. On the other hand, there were no significant differences in semen volume, semen liquefaction time, luteinizing hormone (LH) level in serum, and Cr concentration in both serum and seminal plasma between the exposed workers and the control group. Feeding Cr(VI) to rats significantly reduced the epididymal sperm counts from 87.40+/-3.85 x 10(6)/g epididymis in control group to 21.40+/-1.20 x 10(6)/g epididymis at a CrO(3) dose of 10 mg/kg body weight and to 17.48+/-1.04 x 10(6)/g epididymis at a CrO(3) dose of 20 mg/kg body weight. Exposure of rats to Cr(VI) also significantly increased the sperm abnormality from 2.75+/-0.06% in the control group to 6.68+/-0.32% in the exposed group at a CrO(3) dose of 10 mg/kg body and to 7.6+/-0.15% at a CrO(3) dose of 20 mg/kg body weight. In exposed rats, there was visible disruption in germ cell arrangement near the walls of the seminiferous tubules. The diameters of seminiferous tubules in exposed rats were smaller. These results suggest that occupational exposure to chromium(VI) leads to alteration of semen status and may affect the reproductive success of exposed workers.

Animals↗

PubMed2001

Cyclic GMP-dependent protein kinase activation and induction by exisulind and CP461 in colon tumor cells.

These studies report on the activation and induction of cGMP-dependent protein kinase (PKG) by exisulind and analogs and test the hypothesis that PKG is involved in the induction of apoptosis in colon tumor cells. Exisulind and analogs are proapoptotic drugs developed as inhibitors of cGMP phosphodiesterase gene families 5 and 2 that have been shown to sustain increased cGMP in SW480 and HT29 cells. At concentrations that induced apoptosis, both exisulind and CP461 increased PKG activity in SW480 cell supernatants. PKG activation was dose-dependent and sustained. Activation of PKG by exisulind and analogs was also seen in the colon tumor cell lines HT29, T84, and HCT116. The guanylyl cyclase activators YC-1 and guanylin increased PKG activity secondary to increased cellular cGMP and induced apoptosis in colon tumor cells. Exisulind and CP461 had no direct effect on purified PKG activity or on basal and stimulated PKG activity from cell supernatants. An additional effect of exisulind after 8 h of drug treatment was a dose-dependent increase of PKG Ibeta protein expression. beta-Catenin, a potential new substrate for PKG, whose regulation influences apoptosis, was phosphorylated by PKG in vitro. 32P-labeled cells treated with exisulind showed increased phosphorylation of beta-catenin. These data indicate that exisulind and analogs activate and induce PKG, resulting in increased phosphorylation of beta-catenin and enhanced apoptosis to promote colon tumor cell death.

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed2001

[A simulating study of biophysical features along meridians on a gel model].

A physical model was used to study the mechanism of specific biophysical features along the classic acupuncture meridian lines. A sol channel within a gel bed was made by a resistance string heating during electrification. A saline channel was produced by withdrawing some fibers in the gel bed and injecting saline into the gaps. A hydraulic resistance instrument composed by two pressure transducers was used to measure the hydraulic resistance across the two kinds of channels. The impedance on both channels was measured by a four-electrode impedance instrument with 5 KHz constant current. A vibration generator was put on one set of the channel to produce about 50 Hz sound waves. The signal was detected by a crystal pickup on the other set of the channel to examine the transmission of the wave along the two kinds of channels. The results showed that the low hydraulic resistance appeared on saline channel while no such feature on sol channel. Both channels showed low impedance while saline channel had more marked low impedance than control area. There was a better transmission of sound wave along saline channel while a bad transmission along the sol channel. The results suggest that the specific biophysical feature along meridians may be caused by a continuous rich distribution of interstitial fluid which mainly contains salt, water and protein.

Electric Impedance↗

PubMed2001

[Biomechanical properties of arteries in experimental hypotensive rats].

To study the changes of biomechanical properties after arterial remodeling in hypotension, a model of hypotension was established in rats by constricting the abdominal aorta below the orifice of the left renal artery. The change of opening angles of the abdominal aorta, femoral artery and anterior tibial artery, and the compliance of the abdominal aorta were studied. The relationship between the pressure and volume of the abdominal aorta were also observed in vivo. The results show that non-uniformal remodeling of the hypotensive artery induces the reduction of opening angles in the zero-stress state, the C/E rate of the abdominal artery decreases while the compliance increases.

Animals↗

PubMed2001

Spatial learning deficits in amyloid precursor protein 770 transgenic mice.

OBJECTIVE: To determine whether learning deficits could be seen in transgenic mice expressing human amyloid precursor protein 770 (APP770). METHODS: Female heterozygous transgenic and nontransgenic mice aged 3, 6 and 9 months at the start of testing were used, with eight mice in each age group. All mice were subjected to various behavioral tasks including the Y-maze task and the Morris water maze. After behavioral testing, the mice were sacrificed, and their brain tissues were used for measuring the choline acetyltransferase (ChAT) activity. RESULTS: Nine-month-old transgenic mice exhibited spatial learning deficits in the Morris water maze and in spontaneous alternation in the Y-maze, compared with those of the age-matched non-transgenic mice. The behavioral changes accompanied a reduction of ChAT activity in the cortical and hippocampal regions of transgenic mice. On the other hand, these behavioral deficits were not observed in transgenic mice either at 3 or at 6 months of age, in which ChAT activity remained unchanged. CONCLUSIONS: The present results show that the learning impairment observed in 9-month-old APP770 transgenic mice are accompanied by a decrease in cortical and hippocampal ChAT activities. This suggests that cholinergic deficits may be involved in the learning impairment observed in these APP770 mice. This model will be a useful tool in advancing our understanding of the relationship between the cholinergic system and the cognitive deficits observed in Alzheimer's disease (AD).

Amyloid beta-Protein Precursor↗

PubMed2001

[Clinic intervention study on urogenital mycoplasma infection of pregnant women].

OBJECTIVE: To explore the hypothesis of pathogenic relationship between urogenital mycoplasma infection and adverse perinatal outcomes. METHODS: Four hundred and eighty-eight mycoplasma-positive pregnant women detected by culture method were randomly divided into erythromycine-intervention group and non-intervention group. Comparison was made on rate of reverse sero-conversion, of vertical transmission to mycoplasma and adverse perinatal outcomes incidence between groups. RESULTS: Ureaplasma urealyticum sero-conversion rate and rate of vertical-transmission in intervention group were significantly lower than in non-intervention group (P < 0.05). The incidences rates of preturm labor, post partum fever, puerperal infection and neonate pneumonia in intervention group were significantly lower than in non-intervention group (P < 0.05). CONCLUSION: Erythromycin is effective in control of ureaplasma urealyticum infection among pregnant women through cutting off vertical transmission passway and lowering adverse perinatal outcomes against ureaplasma urealyticum.

Anti-Bacterial Agents↗

PubMed2001

Rhein inhibits renal tubular epithelial cell hypertrophy and extracellular matrix accumulation induced by transforming growth factor beta1.

AIM: To investigate the effects of rhein on cell hypertrophy and accumulation of extracellular matrix (ECM) in the renal tubular epithelial cells. METHODS: LLC-PK1 cells were incubated with transforming growth factor beta1 (TGFbeta1) 2 microg/L for 24 h to induce cell hypertrophy and production of ECM. To evaluate the effects of rhein on inhibiting the action of TGFbeta1, cell volume, cellular protein level, and [3H]leucine incorporation in LLC-PK1 cells treated with rhein at different concentrations were measured. In addition, the [3H]proline incorporation, level of fibronectin (FN) in supernatant, and mRNA expression of collagen IV and FN were also detected in rhein treated cells. RESULTS: The cell volume, cellular protein content, and [3H]leucine incorporation were markedly increased in LLC-PK1 cells after TGFbeta1 stimulation as compared with control (P < 0.01), and this TGFbeta1-stimulated cell hypertrophy was ameliorated by rhein. It was observed that TGFbeta1 not only increased the production of FN and [3H]proline incorporation in LLC-PK1 cells (P < 0.01), but also enhanced the mRNA expression of collagen IV and FN. Rhein significantly decreased the protein production and mRNA expression of ECM in LLC-PK1 cells stimulated by TGFbeta1. CONCLUSION: Rhein can inhibit cell hypertrophy and ECM accumulation in LLC-PK1 cells induced by TGFbeta1, which may partly account for the role of rhein in preventing and retarding the progression of diabetic nephropathy.

Animals↗

PubMed2001

[Effect of natural zeolite on nutrient preserving capability of degraded slope soil in south China].

Soil column leaching experiment showed that after zeolite application, the content of nitrogen and potassium in leachate was reduced significantly, but no significant effect was detected for phosphate. This application had a positive effect on soil available nitrogen, phosphorus and potassium. It increased the content of soil AL-P and Fe-P, but did not increase the NO3-N content in leachate.

Fertilizers↗

PubMed2001

[Activation of NF-kappa B and its effect on induction of platelet-derived growth factor-B transcription by angiotensin II in ECV304 cell line].

OBJECTIVES: The renin-angiotensin system may contribute to the pathogenesis of atherosclerosis. The transcription factor nuclear factor-kappa B (NF-kappa B) participates in most signal pathways involved in the inflammatory process. In this project the effect of angiotensin II (Ang II) on NF-kappa B activation and the promotion of PDGF-B mRNA expression in human endothelial cell line ECV304 was studied. METHODS: Electrophoretic mobility shift assay, immunofluorescence and immunoelectronic microscope techniques, including confocal microscopy and gold particle labelled electronic microscopy were applied to investigate the mechanism by which Ang II activates NF-kappa B, ECV304 cells were transiently transfected with an NF-kappa B/luciferase reporter gene and catalytically inactive NIK, IKK alpha, IKK beta mutants respectively. Northern blot was carried out to detect PDGF-B mRNA. RESULTS: By the findings of immunofluorescence confocal microscopy, immunoelectronic microscopy and Northern blot, Ang II was effective in stimulating NF-kappa B activation and there was definited cytoplasmic-to-nuclear translocation of NF-kappa B subunits p50 and p65 and overexpression of PDGF-B mRNA expression. Over-expression of the transiently transfected IKK alpha-KM, IKK beta-KM and NIK-KM mutant genes enabled to block the reporter gene activation induced by ang II. CONCLUSION: Ang II is effective to activate NF-kappa B through a pathway dependent on NIK, IKK alpha and IKK beta, and induces PDGF-B transcription in the endothelial cell line ECV304.

Angiotensin II↗

PubMed2001

[Effect of different tillage methods on rice growth and soil ecology].

Field experiments were conducted in double-cropping rice field in South China during 1998-1999 to study the effect of different tillage methods on rice growth and soil ecology. The results showed that with rice scattering planting, no-tillage method caused a reduction of rice tillering, effective panicle, and filled grains of rice. Grain yield under no-tillage was 13.40% lower than that under conventional tillage, and the economic benefits decreased by 10.9%. Soil analysis showed that in no-tillage fields, soil bulk density and hardness were increased, soil porosity and available P and K were decreased, the amount of actinomyces and fungi was reduced, while that of soil bacteria was increased, and the enzyme activity was promoted. Minimum tillage and conventional tillage had similar soil physical and chemical properties, soil microbial quantity and enzyme activity. Minimum tillage could produce a 2.1% higher grain yield than conventional tillage, and increase the economic benefits by 11.0%.

Agriculture↗

PubMed2001

[Influence of temperature and relative humidity on epizootiological features of Zoophthora anhuiensis in Myzus persicae colonies].

The colony of green peach aphid, Myzus persicae(Sulzer), which was initiated with 3 pathogen-free apterae and another 3 ones inoculated with the conidia of the entomophthoraceous fungus, Zoophthora anhuiensis(Li) Humber, was maintained on detached cabbage leaves at the regimes of 10-25 degrees C and 90-100% of relative humidity(RH), and allowed for free reproduction and fungal infection. Based on 26 day observations, it was showed that the development of Z. anhuiensis in the colony was rapid at 15 or 10 degrees C, regardless of the humidity range concerned. The cumulative mortality of the aphids attributed to Z. anhuiensis infection was 72.9-98.2% at 10 degrees C on day 26, and 78.7-94.4% at 15 degrees C on day 24, indicating the occurrence of epizootic in the colony. At 20 degrees C, a high-level epizootic occurred only at 100% RH, with a cumulative mortality of 71.6% on day 24, contrasting to a much lower mortality (5.1-12.8%) at the other three humidity regimes. However, the maximal mortality at 25 degrees C on day 20 was only 27.2% even at 100% RH. Obviously, Z. anhuiensis caused aphid epizootic more easily at lower temperature, and to less degree was affected by the humidity. The disease prevalence (represented by the cumulative mortality) was correlated well to temperature, its interaction with relative humidity, and the days from initiation (r2 = 0.82, alpha < 0.01).

Animals↗

PubMed2001

[Establishment and application of experimental animal model for hypertrophic scar].

OBJECTIVE: To establish a real animal model for hypertrophic scar. METHODS: 388 wounds on the ears of 47 rabbits were created including rounds 6 mm in diamiter on ventrol or dorsal side and 1.5 cm x 4.5 cm rectangular wounds. Histological and histochemical analyses, in situ hybridization and cell apoptosis were tested. RESULTS: 70 percent of the wounds can from excess dermal scarring which is similar to human hypertrophic scar. The hight of excess dermal scarring is as 3-4 times high as original ventol skin. The excess scarring can last 150 days at the most. while 80 percent appears on rectangular wounds and it lasts more than 262 days. Large amount of fibroblasts, nodular and spiral structures exist in excessive dermal scarring. Local injection of TGF-beta 1 and IFN-r can promote and inhibit the formation of excessive dermal scarring respectively. SDS-PAGE shows that type III collagen content increased in excessive dermal scarring. In situ hybridization shows long-lasting expression of type I and III precollagen mRNA in excessive dermal scarrint. TGF-beta 1 mRNA also cope with that of precollagen. Fibroblast apoptosis in excessive dermal scarring of this model indicate that fibroblast apoptosis plays an important role in the process of occurrance, development of abnormal scar. CONCLUSION: After wounding, rabbit ears can produce excessive dermal scarring which is similar to human hypertrophic scar. This can be used as an experimental model for the study of cicatrix.

Animals↗

PubMed2001

[Composting process of municipal solid waste with high effective complex microbial community].

The effects of high effective complex microbial community (MECMC) in a combination composting process of municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, organic matter, the carbon, nitrogen ration (C/N). Composting was performed under such conditions: The ratio of MSW:sewage:sawdust:composting of 45:25:15:15 (W/W) and organic matter of 60%, total N of 1.4%, total P of 0.69%, total K of 1.25%, original moisture of 58.5%, original ratio of C/N of 30, aration flow of 0.8 L/min.kg(volatile organic matter). The rates of adding HECMC to treatment 1, treatment 2 and treatment 3 were 2%, 3%, 5% respectively. Control experiment added 3% inactive HECMC. The day of MSW and sludge mature in control experiment, treatment 1, treatment 2 and treatment 3 were 30, 24, 18 and 12, respectivly. This indicated HECMC were effective to compose organic matter and speedup composting change into humus. There are many active bacteria in composting which are favorable for soil.

Bacteria↗