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Biomedical subjects

J Liu

Publications and source records attributed to J Liu.

At least 541 records · Page 30Linked to original sources
PubMed2001

Ovarian follicular growth in sows.

The resumption of ovarian follicular development during lactation and after weaning in sows is a complex process that ultimately determines rebreeding efficiency of sows. Ovarian follicular development before weaning is heterogeneous because multiple patterns of development are observed when individual sows are compared. Sows can have relatively inactive ovaries before weaning with follicles of < 2 mm in diameter. Other sows have non-ovulatory follicular waves in which follicles grow to approximately 5 mm and subsequently regress before weaning. Sows may also have preovulatory follicular development and ovulation, or may develop cystic ovaries before weaning. Weaning is a random event relative to follicular development on the ovary. Therefore, variation in the weaning to oestrus interval in sows is caused by weaning at random stages of follicular development. Most sows experience a rapid period of follicular growth after weaning and return to oestrus within 3-7 days. Delayed intervals to oestrus after weaning are associated with inactive ovaries before weaning (follicles < 2 mm in diameter) or weaning during the regression phase of a follicular wave. An integrated model for follicular growth and oestrus in weaned sows should include endocrine mechanisms (that is, individual differences in insulin, insulin-like growth factor I (IGF-I), LH and FSH), behavioural mechanisms (relationship between follicular growth and the initiation of oestrus) and morphological mechanisms (that is, timing of weaning relative to ovarian follicular development).

Animals↗
PubMed2001

Secretory Expression of Different C-terminal Truncated HCV E1 Proteins in Mammalian Cells and Characterization of the Expressed Products.

Three fragments of the HCV envelope 1 (E1) with different C-terminal truncation at aa310, aa325, aa340 were cloned into the mammalian expression vector pSecTagB. An epitope in the hepatitis B surface antigen, preS1(21--47), were genetically engineered onto the N-terminus of the recombinant protein and used as an affinity tag for detection and purification. The resulting pSec-preS1-E1t310, pSec-preS1-E1t325 and pSec-preS1-E1t340 were transiently expressed in the HeLa cells and the antigenicity, secretory efficiency and glycosylation type of the recombinant E1 proteins were compared. All of the three recombinant proteins could be detected by both preS1 monoclonal antibody and E1 polyclonal antiserum. The expression products were secreted and highly mannose-type glycosylated, with S1E1t325 being secreted, indicating the influence of the hydrophobic regions on the secretion of the E1 protein. Three CHO cell lines expressing the proteins, S1E1t310, S1E1t325 and S1E1t340, were established and the CHO/pSecS1E1t325 was chosen for further study. The secreted S1E1t325 could be enriched from cell culture medium by the preS1 antibody-coupled Sepharose. The glycosylation analysis indicated the lack of complex glycogen even after the E1 was secreted via Golgi complexes. The established stable cell lines and anti-preS1 affinity method could be utilized to enrich and purify the HCV E1 expressed in mammalian cells, and may be used for further characterization of this protein.

Journal Article↗
PubMed2001

Identification of A Protein Interacting with Type 2 Methionine Aminopeptidase by Yeast Two-hybrid System.

Type 2 methionine aminopeptidase (MetAP2) is the molecular target for the fumagillin inhibitors against angiogenesis. Making use of the yeast two-hybrid system with GAL4 DBD-fused MetAP2 as a bait, a human brain cDNA library was screened to isolate protein factors that might interact with MetAP2. Among the 2x10(6) transformants obtained, five positive clones were picked out. Sequence analysis revealed that three of them contained cDNA fragments from flotillin and encode a carboxy terminus (starting from amino acids 145--233, respectively) of flotillin protein. The interaction between MetAP2 and flotillin detected by yeast two-hybrid system suggests that MetAP2 might play a role in some biological processes where flotillin is involved.

Journal Article↗
PubMed2001

[Genetic transformation of Panax ginseng C.A. Meyer induced by root inducing plasmid(Ri) of Agrobacterium rhizogenes].

OBJECTIVE: To obtain the hairy root of Panax ginseng (HRPG). METHOD: HRPG was obtained by infecting the germ-free seedling, cotyledon, leaf the blade, Petiole with Agrobacterium rhizogenes 15,834 harbouring agropine-type Ri plasmid. The transformation was proved by PCR and TLC. RESULT: HRPG grew rapidly on hormone-free medium and showed typical phenotype of hairy root. The induced rate and time can be improved by adding exogenous hormone and AS(hydroxyacetosyringone). PCR analysis confirmed the integration of TL-DNA, including 564 bp rolC sequence in the HRPG. Opine analysis evidenced the integration and expression of TL-DNA. The total saponin in HRPG (2.486%) was higher the than control(1.403% Panax ginseng). CONCLUSION: HRPG grows rapidly and proves high in content of ginseng saponin. This culture system of HRPG will be useful for the production of active components in ginseng.

Panax↗
PubMed2001

[Studies on tissue culture of Dendrobium chrysotoxum Lindl in vitro].

OBJECTIVE: To set up a system for the culture of Dendrobium chrysotoxum in vitro. METHOD: Tissue culture, fire fly luminescence and phenol-H2SO4 method. RESULT: The embryo could germinate with or without light, the MS, 1/2MS, B5, N6 mediums are suitable to the growth and the differentiation of sprout with light, 0.5 mg.L-1 NAA and 1 mg.L-1 6-BA, and ATP have regular changes, the content of polysaccharide was 2.833% in plant and 7.254% in sprout. CONCLUSION: The light has no effects on the embryo germination, but the phytohormone, nitrogen source and organized elements are important to the growth and differentiation of the sprout which should be transferred to the MS, 1/2MS, B5, N6 mediums in time supplemented with NAA [symbol: see text] 6-BA, ATP may be served as the dynamic indication of nourishment demand in the plant. The content of polysaccharide in the sprout is higher and can be utilized.

Culture Techniques↗
PubMed2001

[An experimental study on bone marrow purging in vitro for patients with chronic myelogenous leukemia].

OBJECTIVE: To investigate the effect of IL-2, IFN and bcr-abl AS-ODN on bone marrow purging in vitro for patients with chronic myelogenous leukemia (CML). METHODS: By amplifying in vitro clone forming culture, and purging the bone marrow of 5 CML patients through different combined use of IL-2, IFN and bcr-abl AS-ODN, we compared the effects of 4 combined regimens. RESULTS: It was found that the suppressive effects of the 4th regimen combining IL-2 (800 U/ml), IFN (800 u/ml) and bcr-abl AS-ODN (30 micrograms/ml) on leukemia cell clone forming unit (CFU) were significantly different from the suppressive effects of the other 3 regimens (P < 0.01). With the use of the 4th regimen, the GM-CFU and L-CFU survival rates were 26.91% and 3.49% respectively (P < 0.01). CONCLUSION: The combined regimen of IL-2 (800 U/ml), IFN (800 u/ml) and bcr-abl AS-ODN (30 micrograms/ml) has good effect on selective CML bone marrow purging in vitro and can be used in clinical purging of CML bone marrow.

Bone Marrow Cells↗
PubMed2001

[The role of Fos protein in modulation of dental pain in central nerve system].

OBJECTIVE: The aims of this study were to reveal the relationship between Fos protein expression, the transcription of preproenkephalin (PENK) mRNA, and the change of enkephalin (ENK) level initiated by experimental dental pain, and to understand the central modulation mechanism of dental pain. METHODS: The techniques of Immunohistochemistry in situ hybridization and radioimmunoassay were applied respectively to detect the expression of Fos, the transcription of PENK mRNA, and the change of ENK level in the experimental nucleus of the spinal tract of the trigeminal nerve, caudal part (sp5c) of rats. RESULTS: It was found that Fos protein expression was in a time-dependent manner. Fos appeared half hour after the pain stimulation, and its peak occurred two hours after the pain stimulation, but disappeared slowly four hours later. The transcription of PENK mRNA was seen two hours after the pain stimulation, its peak appeared four hours later and it disappeared eight hours later. The level of ENK increased significantly (P < 0.01) in the caudal part of the spinal tract of the trigeminal nerve four hours after pain stimulation. CONCLUSION: Fos protein may take a part in the central modulation of dental pain by initiating PENK mRNA transcription which led to the increment of ENK.

Animals↗
PubMed2001

[Determination of human PDGF-B promoter binding nuclear protein by capillary electrophoresis].

With the use of 1.0% T, 0% C linear polyacrylamide as sieving matrix, 0.25 x TBE(Tris 89 mmol/L, boric acid 89 mmol/L, EDTA 2 mmol/L) as running buffer and 15 degrees C as column temperature, the human PDGF-B promoter binding nuclear protein can be determined within 50 min with good resolution. The results proved that there are two proteins having strong ability binding human PDGF-B promoter, which similar to that in slab gel electrophoresis. This technique can provide one of the rapid and accurate separation methods in the studying of the formation and repression behavior of DNA binding protein based on PDGF gene as the target.

DNA-Binding Proteins↗
PubMed2001

[Extraction and analysis of profenofos residue in tomato and cabbage by gas chromatography-flame photometric detector].

A quick and effective extraction and clean-up method of profenofos residue in tomato and cabbage is presented. Tomato and cabbage samples were homogenized with a mixture of acetone-hexane (1:1, V/V) using a mechanical homogenizer. The resultant homogenate was cleaned-up by adding active carbon and then filtered under reduced pressure. The filter cake was extracted twice with the same solvent mixture. The filtrates were combined and transferred into a separatory funnel. The organic layer was separated and evaporated to dryness using a rotary evaporator. The residue was dissolved in 2 mL of acetone and transferred into a small glass vial and then determined by GC on a 5% OV-101 Chromosorb W-HP column with flame photometric detector. The results showed that this analytical method can be used for an accurate determination of profenofos residues in tomato and cabbage. The minimum detectable concentration of profenofos in samples was 0.06 mg/kg. The recoveries of profenofos in tomato and cabbage were in the range of 96.2%-105.9% and 94.7%-102.3%, respectively. The relative standard deviations were in the range of 3.7%-4.9% and 3.7%-5.0%, respectively. The tomato and cabbage samples were collected 3 weeks after applying profenofos in the field, and the contents of profenofos were determined. The average contents of profenofos in tomato and cabbage were (13.8 +/- 0.8) mg/kg and (14.4 +/- 0.7) mg/kg, respectively.

Brassica↗
PubMed2001

[Treatment of nuclein 32P colloid perfusion with chronic suppurative maxillary sinusitis].

OBJECTIVE: To determine the effect of nuclein 32P colloid in treatment of chronic maxillary sinusitis (CMS). METHOD: 22 patients (31 sides) with CMS after washing of sinucavity were perfused with nuclein 32P in sinucavity. 20 patients (31 sides) with routine conservative treatment were served as a control group. Two groups were followed up for one year. RESULT: In nuclein group, 27 sides were cured, 4 sides were recurred and the rate of cure was 87%. In routine group, 19 sides were cured, 12 sides were recurred and the rate of cure is 61%. There is significant difference between the two groups (P < 0.01). The treatment active of nuclein group is better than that of routine group. CONCLUSION: Nuclein 32P colloid with the function of ionizing radiation can increase the pathogenic tissue immunocompetence and metabolic course, obstruct the microvascular and promote the absorption of inflammatory exudation and edema subsidence. It can also make the proliferous tissue atrophy thence accelerate the rate of cure of CMS.

Adult↗
PubMed2001

[Posterior semicircular canal occlusion with microwave assisted technique in guinea pigs].

OBJECTIVE: To study the effectiveness of posterior semicircular canal occlusion with microwave assisted technique. METHOD: Posterior semicircular canal occlusion with microwave assisted technique was performed in 20 guinea pigs. Electronystagmography (ENG) and auditory brainstem response (ABR) were recorded preoperatively and postoperatively. Morphological changes were observed under light microscopy. RESULT: Left and right nystagmus returned symmetrical on the 3rd postoperative day. Two ears showed normal symmetrical nystagmus to icc-water stimulation on preoperation and the 30th postoperative day. There were no significant changes of the thresholds of ABR before and after surgery. Histopathological findings revealed that posterior semicircular canal was completely occluded, and that Organ of Corti and crista ampullaris were normal. CONCLUSION: Posterior semicircular occlusion with microwave technique is suggested as an effective and safe treatment for the benign paroxysmal positional vertigo.

Animals↗
PubMed2001

[Determination of optical purity of SR-bioallethrin enantiomers by chiral high performance liquid chromatography].

A chiral stationary phase(CSP) was prepared by coating cellulose-tris (3,5-dimethylphenylcarbamate) onto aminopropylated spherical silica gel. On the CSP, the chiral separation of the bioallethrin enantiomers has been investigated and under the optimum conditions the optical purity of three samples of SR-bioallethrin enantiomers was determined by peak area. The results show that the method established is very ideal for determining the optical purity and evaluating the quality of the samples.

Allethrins↗
PubMed2001

[The effect of culture conditions on the fatty acid composition in the mycelium of the Cephalosporium sp].

The optimal condition of Cephalosporium sp. to culture mycelia and accumulate polyunsaturated fatty acid (PUFA) was researched. The optimal culture condition to get mycelium productivity was: maltose 60 g/L, KNO3 3 g/L, initial pH 6.0, 100 mL medium in 500 mL flask, seeding 25% (v/v), 25 degrees C culture it for 10 days. The optimal condition to accumulation PUFA proportion to total fatty acid was: glucose 10-20 g/L, NH4Cl or (NH4)2SO4 3 g/L, initial pH 4.0, 100 mL medium in 500 mL falsk, seeding 10-20% (v/v) and lighted it when it was cultured. It was suggested that two step could be used in the producing progress. A proposal was put forward that the oileic acid transformed to linoleic acid was the key step to produce PUFA. This proposal gave a base to research the optimal culture condition and enzyme regulation.

Acremonium↗
PubMed2001

[Factors of occupational stress on the working ability of petroleum workers].

The relationship between occupational stress and working ability and their influence factors have been studied. 1230 oil workers in 122 work types of oil industry were selected and an occupational stress questionnaire (OSQ) was filled. The working ability index (WAI) in the female was significantly higher than that in the male (P < 0.0001). The working ability of petroleum workers became lower with the increasing of age, the duration of working time and stress levels (P < 0.001). The correlation on the labor load, adverse factors in the working environment and WAI was negative. It was concluded that the occupational stress could decrease the working ability of petroleum workers.

Female↗
PubMed2001

[Study on effect of moxibustion and guben yiliu III combined with chemotherapy in treating middle-late stage malignant tumor].

OBJECTIVE: To observe the complementary function of moxibustion and Guben Yiliu III (GBYL), a Chinese herbal composite preparation, in combination with chemotherapy. METHODS: Eighty-one patients of middle-late stage malignant tumor were randomly divided into three groups, 16 in the control group treated with chemotherapy alone, 35 in the TCM group treated with chemotherapy combined GBYL and 30 in the TCM combined moxibustion group. The therapeutic effect of treatment was evaluated according to the immediate effect, living quality scoring, etc. RESULTS: The comprehensive living quality score and Karnofsky score dropped significantly in the control group after treatment with significant increase of pain score and decrease of tongue figure score (P < 0.05 or P < 0.01). In the TCM group, the former two criteria lowered less than those in the control group, but no significant difference in the latter two criteria was shown. For those in the TCM combined moxibustion group, all the four criteria were improved better than those in the control group (P < 0.01 or P < 0.05). CONCLUSION: GBYL combined or not combined with moxibustion could improve the living quality of patients received chemotherapy.

Adult↗
PubMed2001

[Synthesis and anticancer activity of 3-[(3'-methyl-4'-(substituted phenyl)-1',3'-butadienyl] indole derivatives].

AIM: To study the synthesis and anticancer activity of 3-[(3'-methyl-4'-(substituted phenyl)-1',3'-butadienyl] indole derivatives. METHODS: Electrophilic-substitution, aldol-condensation, selective-reduction, phase-transfer Wittig reaction and hydrolysis reaction were used in the synthesis of the title compounds. RESULTS: Eleven compounds of 3-[(3'-methyl-4'-(substituted phenyl)-1',3'-butadienyl] indole were synthesized. They are new compounds. Compound 8 showed different inhibitory effects on HL-60, HCT-8 and Bel7402 cell lines in vitro, and its inhibitory rate of antiinflammation was 100% at 10(-5) mol.L-1 concentration. CONCLUSION: Compound 8 showed high anticancer and antiinflammatory activities, and is worth further studying.

Anti-Inflammatory Agents, Non-Steroidal↗