PubMed Health⌕ Search

Biomedical subjects

Li Liu

Publications and source records attributed to Li Liu.

At least 307 records · Page 17Linked to original sources

Combination and cleavage of HBV DNA fragments by triple helix-forming oligonucleotides modified with manganese porphyrin in vitro.

OBJECTIVE: To observe the ability of triple helix-forming oligonucleotides (TFOs) modified with manganese porphyrin to combine with and cleave HBV DNA fractions. METHODS: TFO were modified with manganese porphyrin and acridines, and then reacted with the (32)P labeled HBV DNA fragments at 37 degrees C in vitro (pH 7.4). Electrophoretic mobility shift assays and DNase I footprinting tests were used to show the affinity and specificity of TFO to bind to target sequences. The ability of TFO to cleave HBV DNA fragments was tested by cleavage experiments. RESULTS: TFO modified with manganese porphyrin and acridine could bind to the target sequence in a sequence-dependent manner, with a Kd value of 3.5 x 10(-7) mol/L and a relative affinity of 0.008. In the presence of potassium monopersulfate (KHSO(5)), TFO modified with manganese porphyrin and acridine could cleave the target sequence where the triplex DNA was formed. CONCLUSION: In the presence of KHSO(5), TFO modified with manganese porphyrin and acridine could bind and cleave the target HBV-DNA in a sequence-dependent manner.

DNA↗

[Effects of Arg-Gly-Asp-Ser tetrapeptide on integrin signaling and apoptosis in hepatic stellate cells].

OBJECTIVES: To investigate the effects of Arg-Gly-Asp-Ser (RGDS) tetrapeptide on integrin signaling and apoptosis in fibronectin (FN) -stimulated hepatic stellate cells (HSCs). METHODS: 3H-thymidine incorporation, annexin-V/propidium iodide double-labeled flow cytometry (FCM) and transmission electron microscopy were employed to estimate the influence of RGDS on the proliferation and apoptosis of HSCs. And the adhesion rates were observed by toluidine blue colorimetric assay. The expression of focal adhesion kinase (FAK) mRNA and protein in HSCs was detected using RT-PCR and western blotting analysis, respectively. RESULTS: RGDS tetrapeptide at the concentrations of 25 microg/ml, 50 microg/ml and 100 microg/ml inhibited the proliferation of HSCs and induced HSCs apoptosis in dose-dependent and time-dependent manners, with the apoptotic rates of 9.49%, 27.67%, 31.59%, and the necrotic rates of 3.47%, 5.38%, 9.10%, respectively. Both the rates were higher than those in FN group (apoptotic rate: 3.44%; necrotic rate: 2.39%), F=8.02, P<0.05. After adding RGDS tetrapeptide to HSCs for 2 hours, the adhesive inhibition rates were 8.82%, 29.41% and 45.59%, respectively, which were higher than that in FN group (F=20.58, P<0.01). After exposure of HSCs to RGDS tetrapeptide for 24 hours, FAK protein decreased, and FAK mRNA was down-regulated earlier, about 2 hours after exposure to RGDS tetrapeptide. CONCLUSION: These results suggest that RGDS tetrapeptide may induce apoptosis of HSC in both dose-dependent and time-dependent manners in vitro, which may be related to the disruption of cell matrix adhesion and down-regulation of FAK expression.

Apoptosis↗

[Characteristics of drug-release in vitro of different dextran-dexamethasone conjugates].

AIM: To evaluate the effects of molecular weight of dextran on drug-release of conjugate in vitro by screening colon-specific conjugates. METHODS: The conjugates, synthesized with different molecular-weight dextran and dexamethasone, were incubated in the contents of different parts of rat gastrointestinal tract at 37 degrees C. The release of dexamethasone(Dex) and dexamethasonehemisuccinate was determined by HPLC. The mobile phase consisted of 35% acetonitrile and 65% trisodium citrate (50 mmol.L-1, adjusted to pH 4.1 with phosphoric acid). RESULTS: There was no release of dexamethasone or dexamethasonehemisuccinate from conjugates in the stomach contents. The amount of Dex (including dexamethasonehemisuccinate) released from DexD26 in the contents of colon and cecum was shown to be 4.0 times higher than that released in the contents of proximal and distal small intestine while the amount of Dex (including dexamethasonehemisuccinate) released from DexD50 was shown to be 3.6 times higher. The amount of Dex (including dexamethasonehemisuccinate) released from DexD2 in the contents of colon and cecum and from DexD7.6 were 2.0 times and 1.9 times higher, respectively, than that released in contents of proximal and distal small intestine. CONCLUSION: The molecular weight of dextran showed marked effect on drug-release of the conjugate in vitro, and the conjugates with larger molecular-weight dextran have great potential in colon-specific delivery of dexamethasone.

Animals↗

[An epidemiologic study for relation between the snore and cerebral infarction].

OBJECTIVE: To explore the relation between cerebral infarction and simple, apneic snore. METHOD: A case control comparative study with the exception of influencing factors such as ages, sex, obesity and so on in 60 patients with cerebral infarction and 60 control subjects. RESULT: The probability of cerebral infarction is a little high in all snorer compared with the no snorer. The Odds ratio is 1.709 (95% confidence limits 0.798-3.705). The probability persist high in apneic snore compared with other kind of snore. The Odds ratio is 3.571 (95% CL 1.295-9.849, P < 0.05). The Odds ratio of cerebral infarction is highest in apneic snore compared with normal subjects (Odd ratio = 4.107, 95% CL 1.407-11.99, P < 0.01). CONCLUSION: Cerebral infarction is not obviously related with common snore. It is related significantly with the apneic snore. It indicated that snore is a possible cause of cerebral infarction. The possibility suffering from cerebral infarction is more in people especially in apneic snorer than no snorer.

Aged↗

[Study on meteorological factors-based neural network model of malaria].

OBJECTIVE: In order to provide reliable data for strategies development on prevention, a meteorological factors-based predicating model for malaria forecast was studied. METHODS: Data on malaria occurrence and climate changes from 1994 to 1999 in counties in Yunnan province was collected and analyzed with software packages of FoxPro 6.0 and Excel 5.0. The forecasting model for malaria occurrence was established, using the Neural Network Toolbox of Matlab 6.1 software package. In the studies of forecasting model, data of malaria and meteorological factors from 1994 to 1999 in Honghe state in Yunnan province was chosen. The meteorological factors included average monthly pressure, air temperature, relative humidity, monthly maximum air temperature, minimum air temperature, rainfall, rainday, evaporation and sunshine hours in the study. The established forecasting model was also tested and verified. RESULTS: The BP network model was established according to data of diseases and meteorological factors from Honghe state in Yunnan province. After training the neural network for 100 times, the error of performance decreased from 3.23608 to 0.035862. Verified by fact data of malaria, the efficiency of malaria forecasting was 84.85%. CONCLUSION: Neural network model was effective for forecasting malaria. It showed advantages as: strong ability for analysis, lower claim for data, convenient and easy to apply etc. Neural network model might be used as a new method for malaria forecasting.

Humans↗

[Karyotype analysis of Picris davurica chromosome].

OBJECTIVE: To systematically study Picris davurica Fisch chromosome karyotype. METHODS: Sections combined with micrograph were used to analyse chromosome. RESULTS: Chromosome number of normal diploid was 2n = 10, karyotype formula was K (2n) = 10 = 2 m + 8 sm, the relative length was 2n = 10 = 2 L + 2 M2 + 4 M1 + 2 S, which belonged to "3 A" type. The total length of chromosome groups was 12.51 microns, the total length of long arms was 8.36 microns, the AS. K% was 66.83%. The total volume of chromosome was 11.71 microns3. CONCLUSION: Picris davurica chromosome number and morphological character were clear.

Asteraceae↗

[Record, analysis and application of EGG].

Electrogastrography (EGG) is the cutaneous recording of the myoelectrical activity of the stomach using surface electrodes and it is more and more attractive due to its noninvasiveness. It has been used in medical research and clinical diagnosis. It is evident that with the use of this noninvasive measurements of gastric electrical activity(GEA) that we can diagnose gastric dysfunction. In this article, record, analysis, application and trend of EGG are reviewed.

Electrodiagnosis↗

[Expression of telomerase reverse transcriptase in premalignant esophageal squamous dysplasia].

OBJECTIVE: To study the relationship of human telomerase reverse transcriptase (hTRT) and malignant transformation of esophageal dysplasia. METHODS: Telomerase activity and hTRT expression in esophageal dysplasia (n = 47), squamous cell carcinoma (n = 29) and normal esophagus (n = 11) were detected by telomeric repeat amplification protocol (TRAP) and in situ hybridization, respectively. RESULTS: Telomerase activity was detected in none of the 11 cases of normal esophageal tissues (0%) but in 21 of 47 cases (44.7%) of dysplasia, and in 25 of 29 cases (86.2%) of esophageal squamous cell carcinoma. There were statistically significant differences among the telomerase activity in normal esophagus, esophageal dysplasia, and in squamous cell carcinoma (chi(2) = 5.89, P < 0.05; chi(2) = 11.35, P < 0.01). hTRT mRNA was expressed in none of the 11 cases of normal esophageal tissues (0%) but in 23 of 47 cases (48.9%) of dysplasia, and in 24 of 29 cases (82.8%) of esophageal squamous cell carcinoma. There were statistically significant differences among the expression of hTRT mRNA in normal esophagus, esophageal dysplasia, and in squamous cell carcinoma (chi(2) = 6.99, P < 0.01; chi(2) = 7.32, P < 0.01). Significant correlation was found between the telomerase activity and the expression of hTRT mRNA (chi(2) = 57.91, P < 0.001). CONCLUSION: The mRNA expression of hTRT which paralleled to telomerase activity implied that there was a crucial role to play in regulating the activation of telomerase, and was closely related to the malignant transformation of esophageal dysplasia. hTRT might serve as a new, valuable biomarker to detect esophageal squamous cell carcinoma.

Adult↗

[Clinical characteristics and genetic analysis of rare chromosome aberration in peripheral blood].

OBJECTIVE: To investigate the main clinical characteristics and genetic analysis of rare chromosome aberration in peripheral blood. METHODS: Peripheral blood cells were cultured for 72 hours with routine method and slids performed, and then the slide was read and mode analysis was carried out. The diagnostic standard of rare chromosomal aberation was: 1-2 abnormal kary types were found in every 30, 60, 200 mitotic phass. RESULTS: The main clinical characteristics of 52 cases of individual chromosomal aberation in peripheral blood included: 1. spontaneous abortion; 2. abnormal sex development; 3. reproduction diseases; and 4. morbid and deformity. CONCLUSION: Rare chromosomal aberation should be regarded as chromosomal diseases. Prenatal diagnosis is necessary for people with such chromosomal aberation in their reproductive actions.

Abortion, Habitual↗

[Recombinant replication-defective adenovirus based rabies vaccine].

OBJECTIVE: To construct and characterize recombinant adenoviruses containing glycoprotein (GP) gene from rabies virus CVS-N2C strain. METHODS: To obtain the recombinant adenovirus by pAdEasy system, identify recombinant virus with cDNA sequencing, Northern blot, Dot blot, Western blot and challenge-protection experiment of mice. RESULTS: Recombinant adenovirus showed typical adenovirus morphological characteristics; the viral genome was stable; GP specific mRNA and presence of glycoprotein were determined in rAdGPcvs and rAdGPcvs' infected cells. The glycoprotein produced by recombinant adenovirus had a molecular mass of 66,000, which was similar to that of natural glycoprotein. In the group of rAdGPcvs immunized mice, 87.5%-100% of mice survived from a 35.8LD50/38.0LD50 lethal rabies intracerebral challenge. Finally 73.3%-83.3% of the mice that had received eAdGPcvs survived, and all the Ad5 immunized mice succumbed to rabies. CONCLUSION: Recombinant adenovirus rAdGPcvs and rAdGPcvs' hold great potential to be developed as recombinant rabies vaccines, and at the same time, it is actually the first study that on high neuropathogenicity rabies CVS-N2C glycoprotein based adenoviral recombinants.

Adenovirus E3 Proteins↗

[Late-onset riboflavin-responsive multiple acyl-CoA dehydrogenase deficiency (glutaric aciduria type II)].

OBJECTIVE: Glutaric aciduria type II, or multiple acyl-CoA dehydrogenase deficiency is an autosomal recessively inherited defect of mitochondrial energy metabolism. The authors report two cases of late-onset glutaric aciduria type II, and evaluate the procedures for the diagnosis and treatment of this rare disease. METHODS: The clinical and biochemical characteristics of 2 patients with late-onset glutaric aciduria type II were documented. Case 1 presented with lipid storage myopathy for 3 years. Case 2 presented with intermittent episodes of non-ketotic hypoglycemia and muscle weakness for 9 years. The diagnosis of the 2 cases was confirmed with gas chromatography/mass spectrometry analysis of urine samples. Riboflavin supplementation and a low-fat, low-protein, high-carbohydrate diet were initiated as soon as the diagnosis was made. RESULTS: Organic acid analysis on both untreated cases revealed massive glutaric acid with elevated concentrations of isovalerylglycine, isobutyrylglycine, ethylmalonic acid, adipic acid, suberic acid and other dicarboxylic acids. The clinical manifestations were improved remarkably after the administration of riboflavin and diet control. Consistent improvements of sera enzymes and urine organic acids were observed during the course of treatment. CONCLUSION: Patients with unexplained myopathy, metabolic acidosis or hypoglycemia should be carefully screened for inherited metabolic disorders. Riboflavin in conjunction with appropriate diet control is an effective therapeutic regime for patients with late-onset glutaric aciduria type II.

Acyl-CoA Dehydrogenase↗

[Clinical characteristics and prognosis of 33 children with severe acute respiratory syndrome in Guangzhou area].

OBJECTIVE: Since the outbreak of a highly contagious new pneumonia, atypical pneumonia or severe acute respiratory syndrome (SARS) occurred in Guangzhou area, 33 children with this syndrome were treated in the authors' hospital. The present study aimed to understand clinical characteristics and prognosis of pediatric SARS patients in Guangzhou area. METHODS: Clinical manifestations, laboratory and radiologic findings, therapeutic approaches and prognosis of the 33 children with SARS in Guangzhou area were analyzed. RESULTS: Of the 33 cases, 17 were males and 16 were females. The age was between 3 months to 13 years, and 3 - 12 years old patients accounted for 82%. Five (15%) cases had an evident history of contacting SARS patient before the symptoms occurred. Another 5 (15%) cases had a history that contacts of these patients (family members or friends) developed fever and/or cough later. The most common symptoms in this cohort were fever (100%) and cough (91%). Most of the cases had high fever, higher than 39 degrees C. Near half of the cases had nonproductive cough. The initial blood cells count showed that total white blood cell (WBC) count was (2.5 - 9.7) x 10(9)/L. In 22 (67%) cases the WBC count was < 5.0 x 10(9)/L, and in 10 (30%) WBC was (5.0 - 7.0) x 10(9)/L, in 18 cases most of the WBC were lymphocyte count. Chest radiograph showed patchy infiltrates, in 15 cases the changes were unilateral, and in 18 were bilateral. The radiologic changes developed fast, in some cases the changes progressed from one side to both sides. The opacity was absorbed slowly, significant absorption took in average two weeks. Elevated ALT was found in 3 cases and elevated CK-MB in 2 cases. Treatment included isolation, good ventilation of the ward, bed rest, supportive regimens, low volume oxygen inhalation, use of Chinese traditional medicine, antibiotics to prevent bacterial infection, and anti-inflammation therapy. All the patients recovered and discharged from hospital after a mean period of 10.0 +/- 3.8 days. CONCLUSION: SARS in children may have its own characteristics. The main clinical manifestations were high fever and cough while no severe toxic symptoms, nor respiratory failure was seen; few symptoms or signs suggesting involvement of systems other than respiratory system were seen. Chest radiograph showed uni- or bilateral asymmetric air-space infiltrates which could worsen quickly and were absorbed slowly. Though there were severe changes in the lung, the patients might not have corresponding symptoms or signs. The total white blood cell count in peripheral blood did not increase. All the patients studied had a favorable outcome after the combined treatment.

Adolescent↗

[Activating effects of protein transduction domain mediated BCR/ABL protein on CML T cells].

OBJECTIVE: To study the activating effect of protein transduction domain (PTD) mediated BCR/ABL protein on T cells from CML patients. METHODS: The plasmid containing PTD and b3a2 bcr/abl of CML was constructed by genetic engineering and expressed in E. coli. The peripheral blood mononuclear cells from CML patients were stimulated in vitro with purified PTD-BCR/ABL protein and the expression of the early activation antigen CD(69) on CD(8)(+) and CD(4)(+) T cells was detected by flow cytometry (FCM). RESULTS: The optimal concentration of PTD-BCR/ABL protein for activating CD(8)(+) T cells in vitro was 100 micro g/ml, CD(69) expression peaked in three days stimulation. CD(8)(+) T cells were activated in 10 of 15 CML patients, the expression rate of CD(69) was (15.01 +/- 3.75)%. CD(4)(+) T cells were activated in 4 of 15 patients, the expression rate of CD(69) was (10.32 +/- 3.08)%. Both CD(8)(+) and CD(4)(+) T cells were activated simultaneously in 3 of them. However, neither CD(4)(+) nor CD(8)(+) T cells was activated by stimulation with BCR/ABL protein in all 15 specimens, the expression rate of CD(69) on CD(8)(+) and CD(4)(+) T cells was (1.36 +/- 0.31)% and (1.41 +/- 0.43)%, respectively. There was no difference compared with that of PBS control group (P > 0.05). CONCLUSION: By using a PTD-mediated antigen delivering system, exogenous BCR/ABL protein can be delivered into APC, processed and presented onto surface of APC to activate Ag-specific CD(8)(+) and CD(4)(+) T cells in vitro.

Adolescent↗

[Protective effects of vitamin E on the vascular endothelial cells from oxidative injury by oxidized low-density lipoprotein in vitro].

To study the protective effect of vitamin E on vascular endothelial cells (VEC) damaged by oxidized low-density lipoprotein(ox-LDL). To establish the oxidative injury model of VEC induced by ox-LDL in vitro. The cells were divided into five groups(control group, ox-LDL group and VE-L + ox-LDL, VE-M + ox-LDL, VE-H + ox-LDL group). The cells were protected with varying concentrations of vitamin E solution for 24 hours before exposed to ox-LDL. After another 24 hours, the cells were collected and relative indexes were determined. The results showed that the level of MDA in ox-LDL group was higher than that in the other four groups(P < 0.05). The activities of SOD in ox-LDL group were lower than that in control group and three VE treated groups(P < 0.05). The activities of GSH-Px in ox-LDL group and VE-L + ox-LDL group were lower than that in other groups(P < 0.05). Vitamin E can prevent vascular endothelial cells from oxidized low-density lipoprotein induced oxidative injury.

Animals↗

[Study on selective breeding of medicinal Chrysanthemum morifolium].

OBJECTIVE: To investigate botanical characters and yield of four cultivars of Chrysanthemum morifolium for further study on their genetic diversity and selective breeding. METHOD: The characters were observed and yield was investigated by field randomized block and analysis of variance. RESULT AND CONCLUSION: The botanical characters are difference among four cultivars; the amount of single flower head is the main factor influencing on the output of Chrysanthemum morifolium (r = 0.925); the yield of "Hongxinju" and "Xiaobaiju" are remarkably higher than that of "Dabaiju" and "Changbanju".

Breeding↗

[Study on the soil fertility changes in planting base to develop the special fertilizer for cultivation of Chrysanthemum morifolium].

OBJECTIVE: To study the changes of soil fertility in Sheyang county where Chrysanthemum morifolium has been cultivated for more than 30 years and to develop the special fertilizer for cultivation of C. morifolium. METHOD: The pH values, organic matter and the contents of total and available N, P, K and Zn in the soil layer of 0 to 40 cm, as well as the total N, P, K and Zn contents in the flowers, roots, stems and leaves of the plants, were analysed. The balanced fertilization plan for cultivation of C. morifolium was put forward. In addition, the formula of special fertilizer for cultivation of C. morifolium was determined according to flower yield and utilization rate of N, P, and K. RESULTS AND CONCLUSION: The soil had high pH values and high soil salt contents, with unbalanced application of N, P, and K fertilizers and a shortage of available Zn after cultivation of C. morifolium. The contents of soil organic carbon, N and P declined with increasing cultivation time of C. morifolium, which resulted from the improper rotations and fertilization. The balance fertilization practice and the special fertilizer utilization are effective ways to improve soil fertility for C. morifolium.

Chrysanthemum↗

[Effects of tanguticum maxim polysaccharide on ulcerative colitis induced by TNBS in rats].

OBJECTIVE: To evaluate the effects of Tanguticum Maxim polysaccharide (TMP-1) on TNBS-induced colitis in rats. METHOD: Rats with TNBS/ethanol-induced colitis were used and treated with TMP-1 and dexamethasone (DX). Seventy-two rats, including animals with TNBS-induced colitis, were treated with saline, TMP-1 (100, 200, 400 mg.kg-1) and DX. White blood cells were counted on the fifth day and the rats were killed by ether on the sixth day. SOD activity in serum, MPO and SOD activity of colonic tissue were measured. RESULT: The remarkable effects of TMP-1 at dosage of 200, 400 mg.kg-1 on TNBS-induced colitis were observed. The ulcerative area was diminished and weight of colon was reduced. White blood cell population was reduced, SOD activity in serum and SOD activity of colon tissue were remarkably increased, and, MPO activity of colonic tissue was reduced. CONCLUSION: TMP-1 has significant effects on TNBS-induced colitis in rats with lower side effects, which suggests the effective component of rhubarb on colitis perhaps is TMP. The mechanism of the actions of TMP may relate to its antiflammation, antioxidation and immunoloregulation.

Animals↗