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Biomedical subjects

Q Ye

Publications and source records attributed to Q Ye.

At least 55 records · Page 3Linked to original sources
PubMed2000

Identification of a novel FAS/ER-alpha fusion transcript expressed in human cancer cells.

A semi-nested reverse transcriptase-polymerase chain reaction (RT-PCR) was applied to evaluate the presence of estrogen receptor-alpha (ER-alpha) in human prostate cancer cells. Unexpectedly, a novel fatty acid synthase (FAS)/ER-alpha fusion transcript was identified, in which the N-terminus of FAS was fused in-frame with the C-terminus of ER-alpha. The existence of the FAS/ER-alpha transcript was further confirmed by RT-PCR analysis using various sets of amplification primers and different reverse-transcribed primers in the presence of dimethyl sulfoxide to eliminate the secondary structure of RNA. The predicted FAS/ER-alpha protein would contain largely domain I of FAS and the entire ligand binding domain of ER-alpha. The FAS/ER-alpha was expressed in a variety of human cancer cell lines including prostate, breast, cervical and bladder cancer cell lines. Our data suggest that the presence of FAS/ER-alpha may complicate the FAS and the ER-alpha signalling pathway.

Amino Acid Sequence↗
PubMed2000

Optical detection of polycations via polymer film-modified microtiter plates: response mechanism and bioanalytical applications.

Microtiter plate wells modified with thin (approximately 20 microm) polymeric films capable of optically sensing macromolecular protamine and other polycationic species are described. The plates are prepared by coating the bottom of each well of a conventional 96-well polypropylene plate with an adherent polymer film (a mixture of poly(vinyl chloride) and polyurethane) containing a lipophilic 2',7'-dichlorofluorescein derivative. Surprisingly, optical response toward polycations is shown to result from the extraction of the fluorescein derivative from the polymer film into a lyophobic colloidal phase at the sample/film interface. This new phase is likely composed of a micellular-type ion pair complex between the analyte polycation from aqueous sample phase and the deprotonated form of the fluorescein derivative. Accumulation of the deprotonated fluorescein species in this interfacial region induces an absorbance change measured at 540 nm. Optimized plates can be used to sense protamine concentrations in the range of 0-100 microg/mL in 10 min with little or no response to physiological levels of common cationic species (Na+, K+, Ca2+, etc.). The modified plates are shown to be useful as simple optical detectors for measuring heparin levels in plasma via titrations with protamine and for monitoring protease activities (trypsin and plasmin) that cleave polycationic peptides/proteins such as protamine into smaller peptide fragments that are not detected by the sensing films. Assays for "clot busting" plasminogen activators (streptokinase, urokinase, and tissue plasminogen activator) are also demonstrated using this relatively simple microtiter plate-based polycation detection system.

Cations↗
PubMed2000

A soluble form of human Delta-like-1 inhibits differentiation of hematopoietic progenitor cells.

Two Notch ligand families, Delta and Serrate/Jagged, have been identified in vertebrates. Members of the Jagged family have been shown to affect in vitro hematopoiesis. To determine whether members of the Delta family might play a similar role in hematopoiesis, we examined the expression of mouse Delta-like-1 (mDll1). mDll1 protein was detected in whole marrow and in a marrow stromal cell line MS-5. At the RNA level, both mDll1 and Notch1 were seen in marrow precursor, differentiated hematopoietic, marrow stromal, and MS-5 cells. We isolated a cDNA encoding the human homologue of mDll1, designated human Delta-like-1 (hDll1). A soluble form of hDll1, hDll1(NDSL), containing the DSL domain and the N-terminal sequences, was expressed and purified from bacteria as a glutathione S-transferase (GST) fusion protein. We observed that hDll1(NDSL) delayed the acquisition of differentiation markers by murine hematopoietic progenitor cells (Lin-) cultured in vitro with cytokines. In addition, it promoted greater expansion (more than 3 times) of the primitive hematopoietic precursor cell population, measured in high-proliferative potential colony assay and day 12 colony-forming unit spleen (CFU-S) assay, than GST controls. We also observed that the percentage of apoptotic cells decreased and that the number of cells in the S-phase of the cell cycle increased in the cultures of Lin(-) cells with hDll1(NDSL). The effects of hDll1(NDSL) were blocked by antibody against the mouse counterpart of hDll1(NDSL), mDll1(NDSL). These observations demonstrate that hDll1 plays a role in mediating cell fate decisions during hematopoiesis. (Blood. 2000;95:1616-1625)

Amino Acid Sequence↗
PubMed2000

DepoFoam technology: a vehicle for controlled delivery of protein and peptide drugs.

A major challenge in the development of sustained-release formulations for protein and peptide drugs is to achieve high drug loading sufficient for prolonged therapeutic effect coupled with a high recovery of the protein/peptide. This challenge has been successfully met in the formulation of several peptide and protein drugs using the DepoFoam, multivesicular lipid-based drug delivery system. DepoFoam technology consists of novel multivesicular liposomes characterized by their unique structure of multiple non-concentric aqueous chambers surrounded by a network of lipid membranes. The objective of this paper is to demonstrate that DepoFoam technology can be used to develop sustained-release formulations of therapeutic proteins and peptides with high loading. DepoFoam formulations of a protein such as insulin, and peptides such as leuprolide, enkephalin and octreotide have been developed and characterized. The data show that these formulations have high drug loading, high encapsulation efficiency, low content of free drug in the suspension, little chemical change in the drug caused by the formulation process, narrow particle size distribution, and spherical particle morphology. Drug release assays conducted in vitro in biological suspending media such as human plasma indicate that these formulations provide sustained release of encapsulated drug over a period from a few days to several weeks, and that the rate of release can be modulated. In vivo pharmacodynamic studies in rats also show a sustained therapeutic effect over a prolonged period. These results demonstrate that the DepoFoam system is capable of efficiently encapsulating therapeutic proteins and peptides and effectively providing controlled delivery of these biologically active macromolecules.

Animals↗
PubMed2000

Crystal structure of CHO reductase, a member of the aldo-keto reductase superfamily.

Chinese hamster ovary (CHO) reductase is an enzyme belonging to the aldo-keto reductase (AKR) superfamily that is induced by the aldehyde-containing protease inhibitor ALLN (Inoue, Sharma, Schimke, et al., J Biol Chem 1993;268: 5894). It shows 70% sequence identity to human aldose reductase (Hyndman, Takenoshita, Vera, et al., J Biol Chem 1997;272:13286), which is a target for drug design because of its implication in diabetic complications. We have determined the crystal structure of CHO reductase complexed with nicotinamide adenine dinucleotide phosphate (NADP)+ to 2.4 A resolution. Similar to aldose reductase and other AKRs, CHO reductase is an alpha/beta TIM barrel enzyme with cofactor bound in an extended conformation. All key residues involved in cofactor binding are conserved with respect to other AKR members. CHO reductase shows a high degree of sequence identity (91%) with another AKR member, FR-1 (mouse fibroblast growth factor-regulated protein), especially around the variable C-terminal end of the protein and has a similar substrate binding pocket that is larger than that of aldose reductase. However, there are distinct differences that can account for differences in substrate specificity. Trp111, which lies horizontal to the substrate pocket in all other AKR members is perpendicular in CHO reductase and is accompanied by movement of Leu300. This coupled with movement of loops A, B, and C away from the active site region accounts for the ability of CHO reductase to bind larger substrates. The position of Trp219 is significantly altered with respect to aldose reductase and appears to release Cys298 from steric constraints. These studies show that AKRs such as CHO reductase are excellent models for examining the effects of subtle changes in amino acid sequence and alignment on binding and catalysis.

Alcohol Oxidoreductases↗
PubMed2000

Role of myocardial revascularization in postinfarction ventricular septal rupture.

BACKGROUND: Postinfarction ventricular septal rupture requires urgent closure. The role of systematic coronarography and coronary revascularization needs clarification. METHODS: Fifty-four patients who underwent patch closure of postinfarction ventricular septal defect were reviewed. A coronarography had been systematically and myocardial revascularization selectively (when significant coronary artery stenosis existed) performed. RESULTS: No patient died or deteriorated during coronarography. Twenty-six patients showed no coronary artery disease besides the infarct-related artery, and 28 had associated disease. Threatened myocardial territories were revascularized usually with venous grafts (mean number of distal anastomosis, 2.5). Operative mortality was 19% and 32% (p = 0.36) and late mortality 43% and 53% (p = 0.75) in patients without and in patients with associated coronary artery disease, respectively. Survival curve in both group was similar, at least up to 8 years after operation. CONCLUSIONS: Myocardial revascularization controlled the added risk of associated coronary artery disease in the postoperative period and in median term. A coronarography should be performed in all patients who can be stabilized hemodynamically and myocardial revascularization performed in case of significant stenosis.

Aged↗
PubMed2000

Tissue engineering in cardiovascular surgery: new approach to develop completely human autologous tissue.

OBJECTIVE: In cardiovascular tissue engineering, three-dimensional scaffolds serve as physical supports and templates for cell attachment and tissue development. Currently used scaffolds are still far from ideal, they are potentially immunogenic and they show toxic degradation and inflammatory reactions. The aim of this study is to develop a new method for a three-dimensional completely autologous human tissue without using any scaffold materials. METHODS: Human aortic tissue is harvested from the ascending aorta in the operation room and worked up to pure human myofibroblasts cultures. These human aortic myofibroblasts cultures (1.5x10(6) cells, passage 3) were seeded into 15-cm culture dishes. Cells were cultured with Dulbecco' s modified Eagle's medium supplemented with 1 mM L-ascorbic acid 2-phosphate for 4 weeks to form myofibroblast sheets. The harvested cell sheets were folded to form four-layer sheets. The folded sheets were then framed up and cultured for another 4 weeks. Tissue development was evaluated by biochemical assay and light and electron microscopy. RESULTS: After 4 weeks of culture in ascorbic acid supplemented medium, myofibroblasts formed thin cell sheets in culture dishes. The cell sheets presented in a multi-layered pattern surrounded by extracellular matrices. Cultured for additional 4 weeks on the frames, the folded sheets further developed into more solid and flexible tissues. Light microscopy documented a structure resembling to a native tissue with confluent extracellular matrix. Under transmission electron microscope, viable cells and confluent bundles of striated mature collagen fibers were observed. Hydroxyproline assays showed significant increase of collagen content after culturing on the frames and were 80.5% of that of natural human pericardium. CONCLUSIONS: Improved cell culture technique may render human aortic myofibroblasts to a native tissue-like structure. A three-dimensional completely autologous human tissue may be further developed on the base of this structure with no show toxic degradation or inflammatory reactions.

Analysis of Variance↗
PubMed2000

Fibrin gel as a three dimensional matrix in cardiovascular tissue engineering.

OBJECTIVE: In tissue engineering, three-dimensional biodegradable scaffolds are generally used as a basic structure for cell anchorage, cell proliferation and cell differentiation. The currently used biodegradable scaffolds in cardiovascular tissue engineering are potentially immunogenic, they show toxic degradation and inflammatory reactions. The aim of this study is to establish a new three-dimensional cell culture system within cells achieve uniform distribution and quick tissue development and with no toxic degradation or inflammatory reactions. METHODS: Human aortic tissue is harvested from the ascending aorta in the operation room and worked up to pure human myofibroblasts cultures. These human myofibroblasts cultures are suspended in fibrinogen solution and seeded into 6-well culture plates for cell development for 4 weeks and supplemented with different concentrations of aprotinin. Hydroxyproline assay and histological studies were performed to evaluate the tissue development in these fibrin gel structures. RESULTS: The light microscopy and the transmission electron microscopy studies for tissue development based on the three-dimensional fibrin gel structures showed homogenous cell growth and confluent collagen production. No toxic degradation or inflammatory reactions could be detected. Furthermore, fibrin gel myofibroblasts structures dissolved within 2 days in medium without aprotinin, but medium supplemented with higher concentration of aprotinin retained the three-dimensional structure and had a higher collagen content (P<0.005) and a better tissue development. CONCLUSIONS: A three-dimensional fibrin gel structure can serve as a useful scaffold for tissue engineering with controlled degradation, excellent seeding effects and good tissue development.

Aorta↗
PubMed2000

Constituents of red yeast rice, a traditional Chinese food and medicine.

Detailed analyses were undertaken of the natural constituents of red yeast rice, a traditional Chinese medicine and food known for centuries to improve blood circulation. Preparation of red yeast rice following ancient methods by fermenting the fungal strain Monascus purpureus Went on moist and sterile rice indicated the presence of a group of metabolites belonging to the monacolin family of polyketides, together with fatty acids, and trace elements. The presence of these compounds may explain in part the cholesterol-lowering ability associated with this traditional Chinese food.

Anticholesteremic Agents↗
PubMed2000

Donor and recipient leukocytes in organ allografts of recipients with variable donor-specific tolerance: with particular reference to chronic rejection.

We have attributed organ engraftment to clonal exhaustion-deletion of host-versus-graft and graft-versus-host reactions that are reciprocally induced and governed by migratory donor and recipient leukocytes. The so-called donor passenger leukocytes that migrate from the allograft into the recipients have been thoroughly studied (chimerism), but not the donor leukocytes that remain in, or return to, the transplanted organ. Therefore, using flow cytometry we determined the percentage and lineages of donor leukocytes in cell suspensions prepared from Lewis (LEW) cardiac allografts to 100 days posttransplantation. The LEW hearts were transplanted to naïve untreated Brown Norway (BN) recipients (group 2), to naïve BN recipients treated with a 28-day or continuous course of tacrolimus (TAC) (groups 3 and 4), and to drug-free BN recipients pretolerized by earlier bone marrow cell (BMC) or orthotopic LEW liver transplantation (groups 5 and 6). The findings in the heart cell suspensions were correlated with the results from parallel histopathologic-immunocytochemical studies and other studies of the grafts and of host tissues. Although the LEW heart allografts were rejected in 9.6 days by the unmodified recipients of group 2, all beat for 100 days in the recipients of groups 3 through 6. Nevertheless, all of the long-surviving cardiac allografts (but not the isografts in group 1) were the targets of an immune reaction at 5 days, reflected by dramatic increases in the ratio of leukocytes to nonleukocyte nucleated cells from normal values of 1:5-1:6 to 1:1-5:1 and by manifold other evidence of a major inflammatory event. The acute changes returned to baseline by 100 days in the chronic rejection (CR) free hearts of groups 4 and 6, but not in the CR-afflicted hearts of short-course TAC group 3 or the less-severely damaged hearts of the BMC-prime group 5. The freedom from CR in groups 4 and 6 was associated with a large donor contribution to the intracardiac leukocyte population at 5 days (28.6% and 22% in the respective groups) and at 100 days (30.5% in group 4 and 8.4% in group 6) compared with 2% and 1.2% at 100 days in the CR-blighted allografts of the partially tolerant animals of groups 3 and 5. Whether large or small, the donor leukocyte fraction always included a subset of class II leukocytes that had histopathologic features of dendritic cells. These class II(+) cells were of mixed myeloid (CD11b/c(+)) and lymphoid lineages; their migration was markedly inhibited by TAC and accelerated by donor-specific priming and TAC discontinuance. Although a large donor leukocyte population and a normal leukocyte/nonleukocyte cell ratio were associated with freedom from CR, these findings and the lineage profile of the intracardiac leukocytes were not associated with tolerance in the animals of groups 3 and 4 under active TAC treatment. The findings in this study, singly and in their entirety, are compatible with our previously proposed leukocyte migration-localization paradigm of organ allograft acceptance and tolerance.

Animals↗
PubMed2000

[The relationship of polymorphism of angiotensinogen and angiotensin converting enzyme with essential hypertension].

OBJECTIVE: In order to investigate the candidate genes for essential hypertension(EH), the authors determined the frequencies of M235T allele variation in exon 2 of angiotensinogen(AGT) gene and angiotensin converting enzyme (ACE) gene in 95 normotensives and 87 hypertensives in Chinese. METHODS: Polymerase chain reaction combined with restriction enzyme digestion was used to detect the variation AGT gene while PCR was used to determine ACE gene polymorphism. RESULTS: T235 allele frequency was significantly higher in hypertensive patients than in controls (0.45 vs 0.33, P<0. 05) and it was noticeably higher in male hypertensives. The frequency of ACE D allele in the EH patients with family history was higher than that in controls(0.59 vs 0.41,P<0.05). CONCLUSION: The variation of AGT gene was involved in the pathogenesis of hypertension, especially in male. The ACE D allele was associated with EH with family history.

Alleles↗
PubMed2000

Histological reaction of auditory bulla bone to synthetic auditory ossicle (Apaceram) in rats.

To investigate the biocompatibility of a synthetic auditory ossicle to host bone, small thin Apaceram disks composed of dense hydroxyapatite were implanted under the periosteum of the left auditory bulla in 32 rats for periods ranging from 1 day to 270 days. A sham operation performed on 10 rats served as a control. Decalcified histological sections stained with hematoxylin and eosin were observed using light microscopy. The experiment showed: 1) a time-dependent mature fibrous connective tissue surrounding the Apaceram disk, 2) no evidence of inflammatory reaction caused by the implant from 90 days after implantation until the end of the experiment, 3) no evidence of osteolysis by osteoclasts caused by the implant, and 4) direct contact of bone to the implant on the bone-disk interface at 180 and 270 days after implantation. The findings suggest that Apaceram has a high degree of implant biocompatibility, making it a satisfactory substitute biomaterial for otological reconstructive surgeries.

Animals↗
PubMed2000

Differential diagnosis between hepatic focal nodular hyperplasia and hepatocellular carcinoma with negative alhpa-fetoprotein.

OBJECTIVE: To study the differential diagnosis between hepatic focal nodular hyperplasia (FNH) and hepatocellular carcinoma (HCC) with negative alpha-feto protein. METHODS: To analyse retrospectively the clinical and imaging materials of 18 patients with FNH and 254 patients with AFP negative HCC proven by operation and pathology during March 1996 to March 1999 in our institute. RESULTS: Patients with FNH were largely younger (66.7% under 40 years), discovered accidentally (66.7%), and without hepatitis background (83.3%). Majority of them had a normal liver function (72.0%). A big central artery was found in the lesion with high velocity and low resistant index in 71.4% of patients by color Doppler ultrasound. CT scan showed transient immediate enhancement in 85.7% of patients after bolus injection, being homogeneous (53.3%) and isodensity (73.3%) in the portal vein phase. MR imaging demonstrated early vigorous enhancement (83.3%) and homogenous (66.7%) lesion. In contrast, patients with AFP negative HCC were generally older (85.8% over 40 years), with symptoms (74.0%). A color flow with high velocity and high resistant index was found by color Doppler ultrasound. CT scan showed early heterogenous enhancement (96.6%) after bolus injection and being hypodensity in portal vein phase. MR imaging indicated early heterogeneous enhancement (91.7%). CONCLUSION: FNH shows some typical clinical and imaging features. Therefore, it is feasible to be differentiated from HCC with negative AFP in some of the patients.

Adolescent↗
PubMed2000

Pain as a mutual experience for patients, nurses and families: a perspective from Shanghai, China.

The author of this article visited China for the purpose of helping the faculty of the School of Nursing learn research skills by participating in research--a kind of learn by doing. Both investigators had conducted quantitative studies in the US--one with children and one with adults--that were adapted for use in China. Seeking to also include a qualitative study, the investigators explored several possible research areas. Because pain is a universal phenomena, it was chosen as the subject for the study using the qualitative methodology reported in the first part of this article.

Adult↗
PubMed2000

[Cultivation integrated with acetate acid filtration on Escherichia coli].

A fed-batch fermentation integrated with filtration process was proceeded in a synthetic medium with the use of a hollow-fibre membrane filter. The activity of alpha A interferon reached 1.4 x 10(9) u/L, which was increased 320% over that of a control process. The integrated process was then proceeded in the synthetic medium supplemented with yeast extract during the earlier stage. The addition of yeast extract not only reduced the accumulation of acetate, but also promoted the production of alpha A interferon. The maximum activity achieved 1.9 x 10(9) u/L during the fermentation, which was increased 480% over that of a normal process.

Acetic Acid↗
PubMed2000

[The study on hereditary polymorphism of thiopurine S-methyltransferasein Chinese Han population of Shanghai area].

OBJECTIVE: To gain an insight into the hereditary polymorphism of thiopurine methyltransferase(TPMT) activity in Chinese Han population of Shanghai. METHODS: The present authors measured the erythrocyte TPMT activity in 320 healthy Chinese volunteers and 51 children with acute lymphoblastic leukemia(ALL) by means of radiochemical assay. RESULTS: The TPMT activity levels ranged from 4. 32 to 32.33 U/ml pRBCs, with a mean value of (16.64+/-4.50) U/ml pRBCs, male (16.78+/-4.96) U/ml pRBCs, female (16.52+/-4.44) U/ml pRBCs. Eight point one percent of the sample had low activity. The TPMT activity levels for subjects who were <12 years, 13-18 years, 19-45 years and >45 years old were (16.52+/-4.31) U/ml pRBCs, (16. 71+/-4.24) U/ml pRBCs, (16.28+/-5.21) U/ml pRBCs and (17.11+/-3.98) U/ml pRBCs, respectively; the TPMT activity levels for healthy volunteers and patients with ALL were (16.65+/-4.72) U/ml pRBCs and (16.52+/-4.47) U/ml pRBCs, respectively. CONCLUSION: There were no differences of TPMT activity in gender, age, and between healthy volunteers and patients with ALL.

Adolescent↗
PubMed2000

Hepatocellular adenoma and focal nodular hyperplasia: a series of 24 patients with clinicopathological and radiological correlation.

OBJECTIVE: To investigate two rare benign lesions, hepatocellular adenoma (HCA) and focal nodular hyperplasia (FNH), and evaluate differential diagnosis. METHODS: Twenty-four consecutive patients with presumed HCA and FNH were studied at the Liver Cancer Institute from January 1996 to May 1999. Preoperative assessment included clinical evaluation, symptoms and laboratory tests. New imaging techniques were prospectively appraised in addition to usual techniques. All had hepatic resections and follow-up. Histologic examination of surgical specimens was obtained in all cases. RESULTS: In every instance, FNH was an incidental finding. FNH consists of nodular aggregates of cytologically normal hepatocytes with foci of intranocular bile duct proliferation. In this series, patients with HCA had larger tumors and more often were symptomatic but the occurrence was unrelated to oral contraceptive steroids (OCS) usage. Intralesional hemorrhage or necrosis is common, and was seen in 75% of cases. The best imaging procedure in the diagnosis of FNH was MRI. Color Doppler US was a useful adjunct, but CT lacked specificity, making histological diagnosis mandatory. All patients underwent tumor resected were tumor--free during the follow-up. CONCLUSIONS: FNH is a distinct histopathologic entity, and is distinguishable from HCA. FNH is a hyperplastic response by the liver parenchyma to a pre-existing arterial malformation. HCA is a liver neoplasia and has the potential of malignant transformation to HCC. Based on these findings, we believe that if the clinical suspicion of HCA or FNH is strong, resection is usually the best approach if technically feasible and histologic diagnosis is mandatory.

Adenoma, Liver Cell↗