Biomedical subjects

Jun Liu

Publications and source records attributed to Jun Liu.

At least 379 records · Page 21Linked to original sources

PubMed2002

[Electronic fiberesophagoscopy in video-assisted thoracoscopic surgery for benign esophageal diseases].

OBJECTIVE: To evaluate the effect of electronic fiberesophagoscopy in video-assisted thoracoscopic surgery for benign esophageal diseases. METHODS: We determined the position of lesion, separated the lesion from the esophageal wall, resected the lesion and protected the esophageal mucosa during the process of video-assisted thoracoscopic surgery for benign esophageal diseases. RESULTS: Thirty-six patients with benign esophageal disease underwent the operation successfully and recovered uneventfully. There was no operative death or severe perioperative complications such as esophago pleural fistula. Two patients were changed to undergo thoracotomy. CONCLUSIONS: Electronic fiberesophagoscopy is an essential equipment in video-assisted thoracoscopic surgery for benign esophageal diseases. It should be adopted as a routine equipment to ensure the accuracy, safety, reliability and convenience of this kind of operations.

Adolescent↗

PubMed2002

[Studies of the relationship between the breeding efficiency of anther culture and the use of different hybrid generations as anther-donor plants in wheat].

The wheat haploid plantlets from anther culture were of theoretical and applied interest. Induced haploid spirophytes may play a key role, not only in increasing the efficiency of breeding programs by producing pure lines rapidly, but also in the elucidation of fundamental genetics. However large number of experiments turned out that there are many problems with low rate of green plantlet from anther culture, difficulties of saving plantlets though summer, low rate of double chromosome, extrusive contradiction between technique of wheat anther culture and variety improvement. So wheat anther culture has not played a role in wheat breeding. Studies were carried out on the relationship between the breeding efficiency of anther culture and the use of different hybrid generations as anther-donor plants in wheat. It was shown that previously the low breeding efficiency of anther culture in wheat cross breeding was mainly due to the use of F1 as anther donors. Experimental results demonstrated that the breeding efficiency of anther culture in F1 generation was very low, especially when the doubled haploid population was very small. Based on the experimental results as well as the theoretical analysis this paper proposes that the use of F2 or F3 (especially F3) as anther donors in combination with the conventional selection in the fields will increase the breeding efficiency of anther culture. Under the guidance of this proposal two wheat varieties have been developed within 5-7 years through anther culture.

Culture Techniques↗

PubMed2002

[Experimental reconstruction of extensive anterior defect of rabbit trachea with the use of free auricular cartilage].

OBJECTIVES: To determine whether free auricular cartilage grafts can be used to reconstruct the extensive anterior defect of rabbit trachea and observe the difference between autograft and allograft. METHODS: Twenty New Zealand white rabbits were divided into autograft group (n = 10) and allograft group (n = 10). All grafts were taken from the right auricle, and defect included 8 to 10 rings of trachea. The gross morphorlogical features, endoscopic examinations, biomechanic determinations and histological findings of grafts were assessed at 1,2,4,8 and 12 weeks after operation. RESULTS: Eighteen rabbits survived. Mild tracheal stenosis was observed under endoscope. The maximum stress per mm at 0,4,8 and 12 weeks was 2.54 +/- 0.19, 1.31 +/- 0.21, 1.72 +/- 0.22 and 1.96 +/- 0.08 kPa/mm, respectively. Histological analysis revealed that the viable chondrocytes and neochondrocytes at 12 weeks accounted for 62.0% +/- 3.45%, 65.89% +/- 48% in the autograft group and 60.1% +/- 3.98%, 55.20% +/- 7.57% in the allograft group. No marked immunological differences between the auto- and allograft groups were noted. CONCLUSIONS: Free auricular cartilage can be used to reconstruct the extensive anterior defect of trachea in both auto- and allo-transplantations.

Animals↗

PubMed2002

[Triterpenes isolated from Poria cocos by derivazations].

The separation of triterpene acids was achieved from Poria cocos (Schw.) Wolf by TLC after treatment with Ph2CNN or RX under mild condition followed by selective hydrolysis of ester groupings. Three triterpene acids, 3 beta-acetoxyl-16 alpha-hydroxy-lanosta-8,24(31)-diene-21-oic acid (I), 3-oxo-16 alpha-hydroxy-lanosta-7,9(11), 24(31)-trien-21-oic acid (II) and 3 beta, 16 alpha-dihydroxylanosta-7,9(11), 24(31)-trien-21-oic acid (III) were isolated.

Drugs, Chinese Herbal↗

PubMed2002

[Diagnosis of foreign bodies in trachea and bronchus of children by means of coronal CT scan].

OBJECTIVE: To study the sensitivity, specificity and clinical value of coranal CT scan of trachea and bronchus in diagnoing children's foreign body in bronchus. METHOD: 30 cases of the children with foreign body in their trachea and bronchus were examined by chest X ray (chest X-ray), and by coranal CT scan at the same time. (some of them were compared with axial CT scan.) RESULT: The position of foreign body in trachea and bronchus was definitely diagnosed by coronal CT scan in all cases, of whom, 28 cases with obstructive emphysema; 5 case with obstructive pneumonia and 3 cases with obstructive atelectasis. CONCLUSION: Coranal CT scan could demonstrate the position of foreign body in trachea and bronchus and be helpful in planning surgery.

Bronchi↗

PubMed2002

[Tissue-engineered auricled cartilage: an experimental study].

OBJECTIVE: To study the feasibility of engineering auricled neocartilage with chitosan/polylacticacid-polycrylactone (PLA-PCL) network scaffolds and to search the difference between dynamic and silent chondrocytal culture techniques. METHODS: Chondrocytes from auricled cartilage of 4 weeks old New Zealand White rabbit were seeded onto chitosan/PLA-PCL network. Ten cell-polymer scaffolds were divided into two groups: dynamic group (n1 = 5) with rotating bioreactors and silent group (n2 = 5) with ordinary dishes to culture. Using scan electroscope, grossly histological and immunohistological techniques, the morphological evaluation was done individually at 1st week in vitro, 4th and 8th week in vivo. RESULTS: Chondrocytes adhered and grew up well on the network, but more quantities of chondrocytes, Glycoaminoglygan (GAG) and type II collagen were found in dynamic group. There was an obvious difference between dynamic and silent group (P < 0.05). CONCLUSION: Chitosan/PLA-PCL network scaffold is good for adhesions and growth of chondrocytes. Furthermore, dynamic cell culture method is better than silent method for formation of neocartilage.

Animals↗

PubMed2002

[A rapid method for the identification of untreated Chinese herbs by FT-Raman spectrometry].

In this paper, two groups of Chinese herbs are investigated, one includes four species of rhubarb in which only one is used to treat against diseases and illnesses as Traditional Chinese Medicine, the other group is a common anemarrhena rhizome, it is found to mix with different materials in it. Both of them are directly identified by means of Fourier transform Raman spectroscopy for the first time. The tiny, delicate varied chemical components of different raw Chinese herbs lead to different characters in vibration frequency of Raman functional groups. It is found that the vibration frequency variance follows a certain specific regularity. The method is more precise and quick than traditional approaches. What is more, it will not damage samples.

Anemarrhena↗

PubMed2002

[Protective effect of indirect activator of calcium pump on noise-induced hearing loss].

OBJECTIVE: To investigate the possible protective effect of phorbol-12-myristate-13-acetate (PMA), an activator of protein kinase C (PKC) and indirect activator of Ca2+ pump, on noise-induced hearing loss (NIHL). METHODS: Twenty guinea pigs were divided randomly into two groups, and then perfused with artificial perilymph solutions in one group and with artificial perilymph solutions containing 3 mumol/L PMA in the other one, respectively. All animals were exposed with 100 dB SPL white noise for 2 hours. Cochlear microphonics (CM) and compound action potential (CAP) were recorded from the round window (RW) before noise exposure and 2 hours after noise exposure. RESULTS: There was no significant difference in CAP threshold and CM amplitude between two groups before noise exposure. A significant difference was observed in CAP threshold and CM amplitude between two groups after noise exposure. The amplitude of CM decreased and the threshold of CAP increased in both group after noise exposure, but in the PMA group the decrease of the amplitude of CM was higher while the increase of threshold of CAP lower than that in control (P < 0.05). CONCLUSION: PMA might have partly protective effect on NIHL. These findings indirectly proved that intracellular Ca2+ overload might involve in the mechanism of NIHL.

Action Potentials↗

PubMed2002

[Experimental study of taxol combining accelerated radiation on laryngeal carcinoma cells].

OBJECTIVE: To investigate the effect of taxol combining accelerated radiation on the human laryngeal squamous cell carcinoma Hep-2 cell lines in vitro, and to provide the experimental basis for the usage of these two combined theraputic methods. METHOD: Using techniques of tumor cells culture in vitro, the suppressive and time-dependency effects of taxol (1 x 10(-8) mol/L) combine 2 Gy X-rays generated by accelerator on the human laryngeal squamous cell carcinoma Hep-2 cell lines were observed. RESULT: Cell growth is obviously suppressed in group taxol combined accelerated radiation and it's livability is 11.11%, much lower than accelerated radiation combined taxol. After adding taxol 12 h or 24 h then combined accelerated radiation, the two groups were no difference statistically. Cell livability of group taxol is lower than group accelerated radiation. CONCLUSION: Cell growth is obviously suppressed in the human laryngeal squamous cell carcinoma Hep-2 cell lines after given 1 x 10(-8) mol/L taxol combined 2 Gy X-rays generated by accelerator. Taxol acts as a radiation sensitizer.

Antineoplastic Agents, Phytogenic↗

PubMed2001

Caveolin-1 expression enhances endothelial capillary tubule formation.

The level of caveolin-1 expression closely correlates with the oncogenic transformation of NIH 3T3 cells, the proliferation of human cancer cells, and the differentiation of adipocytes and muscle cells. However, the role of caveolin-1 in endothelial cell proliferation and differentiation remains unknown. Here, we have shown that angiogenic growth factors that stimulate endothelial cell proliferation lead to dramatic reductions in caveolin-1 expression. In addition, using an in vitro Matrigel assay system, we studied the potential role of caveolin-1 in capillary-like tubule formation (i.e. endothelial cell differentiation) using human microvascular endothelial cells (HMEC-1). We showed that the level of endogenous caveolin-1 expression increased in a time-dependent manner when endothelial cells underwent differentiation and that the maximum level of caveolin-1 expression occurred just prior to the formation of capillary-like tubules. Interestingly, overexpression of caveolin-1, via an adenoviral gene delivery system, clearly accelerated endothelial cell differentiation/tubule formation and led to a dramatic approximately 3-fold increase in the number of capillary-like tubular structures. Conversely, down-regulation of caveolin-1 expression, via an antisense adenoviral approach, reduced the number of capillary-like tubules formed by >10-fold. Consistent with the unique function of caveolin-1 in interacting with key signaling molecules, delivery of the caveolin-1 scaffolding domain into the cytoplasm of living endothelial cells was also sufficient to enhance capillary-like tubule formation. Taken together, these results clearly demonstrate that caveolin-1 and the caveolin-1 scaffolding domain play an important positive role in the regulation of endothelial cell differentiation, a prerequisite step in the process of angiogenesis.

Adenoviridae↗

PubMed2001

Nramp1 modifies the fusion of Salmonella typhimurium-containing vacuoles with cellular endomembranes in macrophages.

Salmonella survive and replicate within mammalian cells by becoming secluded within specialized membrane-bound vacuoles inaccessible to the host defense mechanisms. Delayed acidification of the vacuole and its incomplete fusion with lysosomes have been implicated in intracellular Salmonella survival. Nramp1 confers to macrophages resistance to a variety of intracellular pathogens, including Salmonella, but its precise mode of action is not understood. We investigated whether Nramp1 affects the maturation and acidification of Salmonella-containing vacuoles (SCV). A mouse-derived macrophage line (RAW/Nramp1(-)) devoid of Nramp1 and therefore susceptible to infection was compared with isogenic clones stably transfected with Nramp1 (RAW/Nramp1(+)). Intravacuolar pH, measured in situ, was similar in Nramp1-expressing and -deficient cells. SCV acquired LAMP1 and fused with preloaded fluid-phase markers in both cell types. In contrast, although few vacuoles in RAW/Nramp1(-) acquired mannose 6-phosphate receptor, many more contained M6PR in RAW/Nramp1(+) cells. Shortly after closure, SCV in RAW/Nramp1(-) became inaccessible to extracellular markers, suggesting inability to fuse with newly formed endosomes. Expression of Nramp1 markedly increased the access to extracellularly added markers. We propose that Nramp1 counteracts the ability of Salmonella to become secluded in a compartment that limits access of bactericidal agents, allowing the normal degradative pathway of the macrophage to proceed.

Animals↗

PubMed2001

Ovarian tissue cryopreservation: therapeutic prospects and ethical reflections.

Along with improved survival, methods to preserve or restore the fertility potential of young women and children treated with cytotoxic chemotherapy or pelvic radiotherapy have been developed or are in the offing. Surgery, radiotherapy and chemotherapy can all impact on the future ovarian function, but patient and disease tailored application and use of preventive measures can limit ovarian damage. When the loss of reproductive ovarian function is unavoidable, different alternatives to preserve fertility or at least to restore the procreative potential are available. Creation of embryos by IVF, oocyte donation and cryopreservation of mature or immature oocytes are potential issues, the advantages and limitations of which are discussed. Recently, ovarian tissue cryopreservation has spurred interest in the medical literature as well as in the lay press as a method for preservation and restoring fertility. Considering the available data and current state of knowledge, we want to stress that this methodology is still in an experimental phase and we would like to caution against unwarranted enthusiasm of physicians and patients. The medical information preceding the informed consent should mention the actual uncertainties of this method. Moreover, the imperative character of the offer and in particular for paediatric oncological patients, the force of the moral rules that define parental obligations towards children should not be ignored.

Journal Article↗

PubMed2001

High Expression in CHO Cells and Activity of an Anti-P185(erbB2) Mouse/human Chimeric Antibody.

The McAb C25 against human P185(erbB2) specifically inhibits proliferation of cancer cells overexpressing P185(erbB2). In order to decrease HAMA response in clinical therapy of human cancer using McAb, and to express this antibody efficiently in CHO cells, an anti-P185(erbB2) mouse/human chimeric antibody gene containing variable region of C25 gene was constructed. The expression vectors were constructed using genomic DNA of human IgG1 constant region, and using neo and dhfr genes driven by weaker promoters as selectable marker genes. Variable region genes of C25 were cloned by RT-PCR. VL and VH genes of C25 were sequenced and then inserted, respectively, into the light chain and heavy chain expression vectors. The two expression vectors were cotransfected into CHO-dhfr(-) cells with LipofectAMINE. The specificity of the chimeric antibody was verified using cellular-ELISA and immuno-fluorescence techniques. ELISA and RT-PCR were used toconfirm that the chimeric antibody containing both variable region of C25 and human constant region. At 72 h post-transfection, the chimeric antibody could be detected in supernatant of CHO cells by ELISA assay and the yield was 1 mg/L. After the selection by G418, stepwise MTX pressure (1x10(-8) 2.5x10(-7) mol/L) culture was carried out, and the yield of the chimeric antibody was increased up to 100 mg/L. The chimeric antibody was demonstrated to have the antigen specificity to P185(erbB2) and to carry the human antibody constant region by cellular-ELISA, immuno-fluorescence assay, indirect-ELISA and RT-PCR. The chimeric antibody could inhibit proliferation of SKBR(3) and SKOV(3) cells at the same inhibiting rate asMcAb C25. In conclusion, a mouse/human chimeric antibody against human P185(erbB2) with potential of usage in clinical therapy of human cancer was constructed and highly expressed.

Journal Article↗

PubMed1999

Consequence alimentary reconstruction in nutritional status after total gastrectomy for gastric cancer.

AIM:To investigate the effect of gastroenteric reconstruction on the nutritional status of patients with gastric cancer after total gastrectomy.METHODS: From 1989-1994, nutritional status was studied in 24 patients, including 12 patients with the gastric reservoir and pyloric sphincter reconstruction (GRPS), 7 with Braun's esophago-jejunostomy (EJ) and 5 with Lawrance's Roux en Y reconstruction (RY).The ability of these patients to ingest and absorb the amount of nutrients was examined and compared, and metabolic balance test was performed to compare the efficiency of those patients to accumulate and use the absorbed nutrients.RESULTS:In the controlled hospital situation, the amount of food ingested by all the patients was greater than that required for maintenance of ideal body weight. In direct contrast, food intake in most patients with EJ or RY reconstruction significantly decreased when the patients returned home and that in EJ patients it was the lowest. The overgrowth of anaerobic bacteria was found in the jejunum in the patients with EJ and RY, due mainly to food stasis in the duodenum or in the Roux limb,caused by the operative procedure itself. In patients with GRPS,because of restoring of the alimentary continuity according to the normal digestive physiologic characters, all the nutritional parameters could fall in the normal range.CONCLUSION:The most common mechanism responsible for postoperative malnutrition was inadequate food intake. Having solved the problem of alkaline reflux esophagitis, it is imperative to preserve the duodenal food passage to reduce malabsorption and other complications after total gastrectomy.

Journal Article↗

PubMed1998

Telomeric associations of chromosomes in patients with esophageal squamous cell carcinomas.

AIM:To investigate the role of telomeric association in the development of esophageal cancer.METHODS:Using chromosome R banding technique,telomeric association of chromosome in peripheral blood lymphocytes from 16 untreated patients with esophageal squamous cell carcinoma were observed and 16 healthy adults served as controls.RESULTS:The teloemeric association frequencies of cell and chromosomes were significantly higher than those of controls(X(2) = 9.56,P <0.01), but its distribution on the chromosome showed no significant difference (X(2) =1.01, P >0.05) between the two groups.CONCLUSION:Chromosomal instability can be initiated by telomeric associations, and sequential chromosome analysis can aid the understanding of the tumor occurrence and progression.

Journal Article↗

PubMed1998

A prostate-specific Protein Factor Inhibits the Interaction of Androgen Receptors with Hormone Response Elements.

The fragments of the androgen receptor (amino acids: 359-732) and of the glucocorticoid receptor (amino acids: 396-548) were expressed in E. coli as fusion proteins with GST. Both fusion proteins, denoted GST-AR and GST-GR, contained the DNA-binding domain and some flanking amino acids. In gel retardation assay both fusion proteins could bind the androgen/glucocorticoid response element (ARE/GRE). We found that both cytosol and nuclear extracts from rat ventral prostate (v.p), but not from other source tested could abolish the interaction of GST-AR and GST-GR with ARE/GRE (from C3 (1) gene and MMTV LTR). The inhibition was androgen-dependent and sensitive to temperature and trypsin treatment. It implies that a protein inhibitor was present in the rat ventral prostate.

Journal Article↗

PubMed1997

The Interaction of Recombinant Androgen Receptor with the Androgen Responsive Element.

A 1 119 bp (1105 to 2224) fragment of androgen receptor (AR) cDNA, named AR1 (containing the whole DNA binding domain, the hinge site region and the partial hormone binding domain) was constructed into an expression vector pGEX. The GST-ARI fusion protein was expressed in E. coli induced by IPTG and purified from glutathione-Sepharose-4B affinity column. With a known ARE of the C3(l) gene as positive probe, the expressed product was proved to be AR with high ARE-binding affinity by gel shifting assay(EMSA) and in vitro Dnase I footprinting analysis.

Journal Article↗

PubMed1996

An Unknown Protein Binding Specifically to the Coding Strand of the Estrogen Responsive Element.

An unknown protein, Designated ERE-C-SSBP, which binds to the single coding strand of estrogen response element (ERE) tightly and specifically, has been discovered unexpectedly during an attempt to establish an ER-ERE gel retardation assay with a 13 bp core fragment of the ERE as a probe. Some of its characteristics, such as subcellular location, tissue distribution, heat stability and relation with divalent metal ions are reported. Interestingly, it may be down-regulated by estrogen. Its value in 29 breast carcinoma samples is to some degree in reverse correlationship with that of ER. The significance of these findings is discussed.

Journal Article↗