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Biomedical subjects

Zheng Zhou

Publications and source records attributed to Zheng Zhou.

At least 55 records · Page 3Linked to original sources
PubMed2005

[Ex vivo expansion of Valpha24 natural killer T cells with alpha-galactosylceramide].

OBJECTIVE: To evaluate the method for expanding Valpha24 natural killer T (NKT) cells with alpha-galactosylceramide (alpha-GalCer) ex vivo. METHODS: Mononuclear cells (MNCs) isolated from adult peripheral blood or umbilical cord blood (UCB) were divided into three groups. In Group A1 (n = 5), CD34+ progenitorderived dendritic cells were differentiated in a cytokine-supplemented culture system from cord blood and acted as antigen presenting cells (APC) to induce the expansion of cord blood Valpha24 NKT cells in presence of alpha-GalCer; in Group A2 (n = 5), adult peripheral monocyte-derived dendritic cells (Mo-DC) were used as APC to induce the expansion of adult peripheral NKT cells in presence of alpha-GalCer; whereas in Group B (n = 16), alpha-GalCer was added into adult peripheral MNCs culture system without additional DCs. Cytokine-produce were measured by ELISA, and NKT cells' proliferation ability, cytotoxicity, and suppressive effect on mixed lymphocyte reaction (MLR) were examined by MTT assays. RESULTS: Valpha24 NKT cells in Group A1, A2, and B were expanded up to 128 (95-207), 250.5 (179.6-790.6), and 326 (101-2 136) -fold by day 12, respectively. Adult NKT cells expanded in Group B were markedly better than those in Group A1 (P = 0.038). When stimulating by PMA, the NKT cells had a 3-day stimulate index of 1.80 +/- 0.41; and the secretion ratio of IL-4 to IFN-gamma of UCB or adult peripheral blood NKT cells were 0.30 +/- 0.13 and 0.28 +/- 0.18; and the ex vivo antitumor effect of expanded NKT cells were found in cell line HL60, KG1a, and Raji except for K562; and the suppressive effect of expanded NKT cells or the culture supernatant on MLR were confirmed. CONCLUSIONS: Alpha-GalCer can facilitate the rapid shorttime expansion of Valpha24 NKT cells in presence of IL-2 and IL-15. These expanded NKT cells, kill tumor cell lines, and inhibit can massively excret IL-4 and IFN-gamma allogeneic T-cell response.

Antigens, CD34↗
PubMed2005

[HLA-identical sibling allogeneic hematopoietic stem cell transplantation for chronic myelogenous leukemia in first chronic phase. Analysis of 51 cases].

OBJECTIVE: To evaluate the treatment outcome of HLA-identical sibling allogeneic hematopoietic stem cell transplantation (allo-HSCT) for chronic myelogenous leukemia (CML) patients in first chronic phase (CP(1)). METHODS: Fifty-one patients with CML-CP(1) received HLA-identical sibling allo-HSCT with conditioning regimens of TBI plus Cy or Bu plus Cy. Allogeneic peripheral blood stem cell transplantation (PBSCT) and bone marrow transplantation (BMT) were performed for 28 and 23 patients, respectively. The median follow-up duration was 1434 (60 - 4062) days. RESULTS: Fifty (98.0%) patients were successfully engrafted. Transplant-related mortality occurred in 8 (15.7%) patients. Acute graft-versus-host disease (aGVHD) occurred in 35 (68.6%) patients and 11 (21.6%) patients were grade II-IV, while chronic GVHD (cGVHD) did in 17 (37.8%) patients. Five (7.4%) patients relapsed. The 5-year probability of disease-free survival (DFS) was (79.2 +/- 6.4)%. There was no significant difference in 5-year DFS, death rate and treatment related syndromes between the two conditioning regimens (P > 0.05), and in 5-year DFS, relapse rate and death rate between two transplant choices (P > 0.05). However, the rate of relapse was lower in Bu/Cy group (P < 0.01) and the rate of cGVHD was higher in allo-PBSCT group (P < 0.05). CONCLUSIONS: Allo-HSCT can cure a significant proportion of patients with CML-CP(1). There was no significant difference in DFS between the two different conditioning regimens and between the different transplant choices. Donor lymphocyte infusion is a therapeutic alternative for CML patients relapsed after transplantation.

Adult↗
PubMed2005

[Effects of mesenchymal stem cells on expansion potential and adhesion molecules expression of cord blood CD34+ cells].

OBJECTIVE: To explore the effects of bone marrow mesenchymal stem cells (MSCs) on in vitro expansion potential, the adherent molecules expression of cord blood (CB) CD34(+) cells. METHODS: MSCs were obtained from human bone marrow and their differentiation function and phenotype were identified. CB CD34(+) cells were expanded in culture systems with or without MSC layer. Hematopoietic progenitor cells and adhesion molecules expression were assessed by semisolid culture assay and flow cytometry. RESULTS: Thy-1, SH2, SB10, CD44, CD13, CD49e and CD29 were highly expressed on MSCs with no expressions of CD34, CD45, HLA-DR, CD14 and CD31. The MSCs could differentiate into adipocytes and osteoblasts under specific induction conditions. After culturing on MSCs layer with supplement of cytokines for 8 days, the absolute numbers of nuclear cells, CD34(+), CD34(+)CD38(-), CD34(+)CD62L(+) cells and CFU-Cs were increased by 145.57 +/- 17.89, 37.47 +/- 13.78, 69.78 +/- 50.07, 10.74 +/- 5.89 and 20.73 +/- 5.54-folds, respectively, being significantly higher than that cultured with cytokines alone. The expression of ALCAM, VLA-alpha4, VLA-alpha5, VLA-beta1, HCAM, PECAM and LFA-1 on CD34(+) cells remained unaffected. The expressions of ICAM-1 and L-selectin were downregulated during expansion, while the absolute numbers of CD34(+)CD62L(+) and CD34(+)CD54(+) cells were increased. CONCLUSIONS: MSCs layer improves expansion of CB CD34(+) cells while inhibiting their differentiation and retaining their homing ability.

Antigens, CD34↗
PubMed2005

[Relationship between different renal functional state with therapeutic effect on diabetic foot ulcers].

OBJECTIVE: To study the relationship between renal functional state and the therapeutic effect and prognosis of foot ulcers in the patients with diabetic mellitus. METHODS: The renal function was evaluated in term of glomerular filtration rate, microalbuminuria, proteinuria, blood urea nitrogen (BUN) and creatinine (Cr) levels in 126 patients with I-V class diabetic foot ulcers (according to Wagner classic standard) before the treatment, and then these patients were divided into 1-5 classes (according to Mogenson standard) and given systemic treatment and local debridement, with astragalus for topical application. The time of growth of granulation tissue (GT), the time of healing (HT), the amputation rate and mortality were observed. RESULTS: GT and HT of ulcer prolonged with worsening of diabetic nephropathy regardless of the disease phase of foot ulcers, especially the GT and HT of foot ulcers were significantly longer in IV and V phases of diabetic nephropathy than those of III phase diabetic nephropathy though the conditions of their foot ulcers were about the same. GT and HT in all the patients with the foot ulcers in the similar condition exhibited significantly positive linear correlation with the severity of diabetic nephropathy (r(1)=2.344 and r(2)=2.563, respectively, both P<0.05). The mortality of I-III phase diabetic nephropathy was significantly lower than that of IV and V phase diabetic nephropathy when the foot ulcers of these patients were of the same extent (P<0.05). CONCLUSION: A worsening of renal function would affect the treatment effect and prognosis of foot ulcers in the patients with diabetic foot ulcers, implicating that it is very important to improve the renal function in the treatment of patients with diabetic foot ulcers.

Combined Modality Therapy↗
PubMed2004

Structural examination of phi-value analysis in protein folding.

Protein folding intermediates and transition states are commonly characterized using a protein engineering procedure (Phi-value analysis) based on several assumptions, including (1) intermediates and transition states have native-like conformations and (2) single mutations from larger hydrophobic residues to smaller ones do not perturb their structures. Although Phi-value analysis has been widely used, these assumptions have not been tested to date because of the lack of high-resolution structures of intermediates and transition states. We recently have determined the structure of a folding intermediate for a four-helix bundle protein (Rd-apocytochrome b(562)) using NMR. The intermediate has the N-terminal helix unfolded. The other three helices fold in a native-like topology with extensive non-native hydrophobic interactions. Here, we have determined the Phi values for 14 hydrophobic core residues, including those with significant non-native interactions. All of the Phi values are in the normal range from 0 to 1, indicating that these non-native interactions cannot be identified by the common Phi-value analysis, and therefore, the first assumption is not valid for this intermediate. We also determined the structure of a mutant (F65A) of the intermediate and found that the structure of the intermediate is not perturbed by the mutation, supporting the second assumption. Together, these results suggest that Phi-value analysis may be valid for characterizing the energetics of the interactions between the mutated residue and others, but not for determining the detailed structures of intermediates and transition states because non-native interactions may exist and may not be identifiable by the common Phi-value analysis.

Alanine↗
PubMed2004

Mixed macromolecular crowding accelerates the oxidative refolding of reduced, denatured lysozyme: implications for protein folding in intracellular environments.

The oxidative refolding of reduced, denatured hen egg white lysozyme in the presence of a mixed macromolecular crowding agent containing both bovine serum albumin (BSA) and polysaccharide has been studied from a physiological point of view. When the total concentration of the mixed crowding agent is 100 g/liter, in which the weight ratio of BSA to dextran 70 is 1:9, the refolding yield of lysozyme after refolding for 4 h under this condition increases 24% compared with that in the presence of BSA and 16% compared with dextran 70. A remarkable increase in the refolding yield of lysozyme by a mixed crowding agent containing BSA and Ficoll 70 is also observed. Further folding kinetics analyses show that these two mixed crowding agents accelerate the oxidative refolding of lysozyme remarkably, compared with single crowding agents. These results suggest that the stabilization effects of mixed macromolecular crowding agents are stronger than those of single polysaccharide crowding agents such as dextran 70 and Ficoll 70, whereas the excluded volume effects of mixed macromolecular crowding agents are weaker than those of single protein crowding agents such as BSA. Both the refolding yield and the rate of the oxidative refolding of lysozyme in these two mixed crowded solutions with suitable weight ratios are higher than those in single crowded solutions, indicating that mixed macromolecular crowding agents are more favorable to lysozyme folding and can be used to simulate the intracellular environments more accurately than single crowding agents do.

Animals↗
PubMed2004

SVZa neural stem cells differentiate into distinct lineages in response to BMP4.

Neural stem cells (NSCs) reside in the anterior portion of the forebrain subventricular zone (SVZa) and generate the progenitors which will differentiate into neurons, and via a tangential migratory pathway, known as the rostral migratory stream (RMS), migrate to the olfactory bulbs (OB). Bone morphogenetic proteins (BMPs) play significant roles in neural development at different stages and locations, but their roles have not been determined in the SVZa. To explore possible roles of BMPs in SVZa NSCs, BMP4 at various concentrations were tested for their capacity to induce SVZa NSCs. The expression of BMP4 was also examined in living cells using a reportor vector, in which the BMP4 promotor was conjugated with red fluorescent protein (RFP). In the meantime, the differentiation of SVZa NSCs was dynamically monitored by using reportor vectors of the Nestin enhancer and the promoters of TH and GFAP. In the OB, high expression of BMP4 was found using both promoter activity analysis and in situ hybridization. However, low BMP4 expression was found in the RMS and only moderate expression of BMP4 was displayed in the SVZa. The results also demonstrated that low concentrations (1-5 ng/ml) of BMP4 promoted the proliferation of SVZa NSCs but high concentrations (10-100 ng/ml) of BMP4 inhibited this proliferation. BMP4 enhanced neuron commitment before 4 days but inhibited it after 4 days. As the antagonist of BMP4, Noggin almost completely blocked all these BMP4 responses. Thus, our findings indicate that BMP4 promotes the exit from the cell cycle and triggers the differentiation of neuron progenitors in the OB. BMP4 also promotes the proliferation of the committed neuron progenitors in the RMS, but in the SVZa, BMP4 may facilitate the commitment of NSCs into astrocytes.

Animals↗
PubMed2004

Cross- and within-cultural variations in children's understanding of distance, time, and speed interrelationships: a follow-up study.

A problem with interpretations of differences in mathematic achievement between students from Asian countries and those from the United States is the seemingly implicit assumption of the cultural homogeneity of Asian societies. Researchers rarely measure the effects of variables within cultures that are hypothesized to be related to differences across cultures. In the present study, the authors examined the effects of socioeconomic status (SES) and quality of instruction on Chinese students' (1st, 3rd, and 5th grades) understanding of distance, time, and speed. The results indicated that (a) low SES in China can impede the development of children's mathematical cognition and (b) higher SES does not guarantee better performance. The implication is that the gap in mathematical performance between socioeconomically advantaged and disadvantaged children can be narrowed or even eliminated through instructional practices that focus on the systematic training of children's mathematical thinking.

Child↗
PubMed2004

[Expression of testosterone in the rapid growing rat condylar cartilage and the expression changes after the function mandibular advancement].

OBJECTIVE: To investigate the expressions of Testosterone in the condylar cartilage of rapid growing rats. METHODS: The mimic functional appliances were used in experiment groups and rats were killed after 3 days, 1 week, 2 weeks, 3 weeks and 4 weeks. Immunohistochemical technique was used to detect the expression of T. RESULTS: T was expressed throughout the condylar cartilage. The Highest expressions were in mature layers of both experiment and control groups. Along with the maturation, the expressions of T in the condylar cartilage were changed respectively, and the immunostain levels in the mature layer of experiment groups 2 and 3 weeks were higher than those of control groups (P < 0.05). CONCLUSION: 1. T is a member of cartilage growth and development control system. 2. The orthopedic mechanism of functional appliance may be conducted by T.

Animals↗
PubMed2004

[Second allogeneic transplant for leukemia relapsed after first allogeneic transplantation].

OBJECTIVE: To evaluate the efficacy of second allogeneic hematopoietic stem cell transplantation (allo-HSCT) for treatment of leukemia relapsed after first allo-HSCT. METHODS: Nine patients with relapsed acute leukemia (5 AML, 4 ALL) and one with chronic myelogenous leukemia (CML) who showed cytogenetic relapse after first allo-HSCT received second allo-HSCT. The median relapse time from the first allo-HSCT was 141 days. Conditioning regimens for second allo-HSCT were combination chemotherapy based on moderate-dose Ara-C (n = 5), Bu (n = 3), conventional-dose Ara-C (n = 1) and Flud/Mel (n = 1). Prophylaxis for acute graft-versus-host disease (aGVHD) were CsA alone (n = 2), CsA/MTX (n = 1), FK506 (n = 1), and no prophylaxis in 6. The median number of peripheral blood mononuclear cells transfused was 6.1 x 10(8)/kg. RESULTS: Eight cases were evaluable. All of them were engrafted and 7 developed aGVHD (grade I 4, grade II 3). The median time for absolute neutrophil count (ANC) > 0.5 x 10(9)/L and platelets > 20 x 10(9)/L were 11 and 12 days, respectively. Five cases developed localized chronic GVHD. Of all the 10 cases received second allo-HSCT, 8 died from interstitial pneumonia (n = 2), multiple-organ failure (n = 1), sepsis (n = 1), fungous pneumonia (n = 1), and leukemia relapse (n = 3), and 2 survived without leukemia for +986 and +1913 days, respectively. The leukemia free survival, transplantation related mortality and relapse rate at 2 year were 20%, 50% and 30%, respectively. CONCLUSION: Second allo-HSCT is a therapeutic alternative for selected patients with relapsed leukemia after first allo-HSCT.

Adult↗
PubMed2004

[Clinical observation on treatment of acute gouty arthritis by tongfengkang].

OBJECTIVE: To objectively evaluate the clinical therapeutic effect of tongfengkang (TFK) in treating acute gouty arthritis. METHODS: Adopting randomized single blinded controlled trial, the 40 patients were equally divided into two groups. The tested group was treated with TFK, the control group was treated with indomethacin and allopurinol, the therapeutic course for both groups was 10 days. RESULTS: The clinical cure rate in the tested group and the control group was 30% and 35% respectively, and the total effective rate 90% and 95% respectively, with no significant difference between the two groups (P > 0.05). The scores of blood uric acid and symptom significantly lowered in both groups after treatment (P < 0.01), but showed no significant difference between them (P > 0.05). Adverse reaction to the treatment was shown in 3 patients in the control group. CONCLUSION: The therapeutic effect of TFK is similar to that of indomethacin plus allopurinol but with less adverse reaction, it is an effective and safe remedy for treatment of acute gouty arthritis, and worthy for further studying and developing.

Acute Disease↗
PubMed2004

[Color stability of porcelain-fused-to-titanium restorations after repeated firings].

OBJECTIVE: To study the effect of repeated firings on color of porcelain-fused-to-titanium restorations. METHODS: Twenty standard porcelain-fused-to-titanium specimens were made with Dentsply DETREY TiBond C3 and Dentaurum rematitan Til. Then they were fired 1, 2, 4, 7, and 10 times. Color measurement was done after each firing. RESULT: Most of the color parameters had no significant difference after firing except for a* and Hab. All the color difference among groups were smaller than 1.0 (deltaE < 1.0). CONCLUSION: Repeated firings will not affect the color stability of porcelain-fused-to-titanium restorations.

Color↗
PubMed2004

[T-bet gene expression in acute graft versus host disease].

OBJECTIVE: To study the role of T-bet [a T helper 1 (Th1) lymphocyte transcription factor] gene expression in predicting acute graft-versus-host disease (aGVHD) and evaluate the correlation between T-bet gene and aGVHD. METHODS: Twenty patients who underwent allogeneic stem cell transplantation (allo. HSCT) entered this study. The expression of T-bet gene was examined with reverse transcription (RT)-PCR in bone marrow samples collected from patients on the day before conditioning, and day 0, day 14, day 28, and day 42 after HSCT. RESULTS: The expression level of T-bet in patients developed aGVHD was increased compared with that before conditioning (P = 0.043). The incidence of aGVHD was 91.7% in patients whose T-bet expression level was increased on day 14 after transplant while was 12.5% in those whose T-bet gene expression level was not increased on that day (P < 0.001). CONCLUSION: Patients with increased expression levels of T-bet after allo-HSCT may have an increased possibility to develop aGVHD. T-bet expression level may serve as an advisable guide to the clinician in predicting aGVHD and monitoring treatment.

Adolescent↗
PubMed2003

New direction in PACS education and training.

The picture archiving and communication system (PACS) is an image information system that has become widely installed. For its successful implementation, training has been found indispensable. A review of PACS training thus far shows major emphasis was placed on the use of display workstations. As an integrated system, the PACS is much broader than the display workstations, having many components that need connectivity and customization. With the many potentials of further development, a more comprehensive education program on PACS is called for and a PACS simulator as a standalone training and research tool is deemed necessary.

Computer Simulation↗
PubMed2003

Protective effect of nerve growth factor on neurons after traumatic brain injury.

The protective effect of nerve growth factor (NGF) on neurons after traumatic brain injury (TBI) was investigated. A brain trauma model of fluid-percussion in rats was established, and 7s NGF was infused continuously in its cerebral ventricle. The activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), and [Ca2+]i overloading in brain tissues was observed after giving exogenous NGF postinjury. We found that the activity of SOD, GSH-Px, and CAT was markedly higher in NGF-treated group than in the simple trauma group (P < 0.01). Although the level of [Ca2+]i in the NGF-treated group increased, the value was significantly lower than that in the simple trauma and control groups (P < 0.01). These findings suggest that exogenous NGF can (a) increase the activity of the major antioxidant enzymes in brain tissues and attenuate the injuries to neurons induced by oxygen-free radicals, (b) reduce the severe overload of [Ca2+]i and stabilize its homeostasis, and (c) provide clear protective effects on neurons after traumatic brain injury.

Animals↗
PubMed2003

[Enhancement of the production of SAM by overexpression of SAM synthetase in Pichia pastoris].

S-Adenosyl-L-methionine(SAM) is an important metabolic intermediate in the metabolic flux of sulphur. SAM is involved in three key metabolic pathways: transmethylation, transsulfuration and polyamine synthesis. As a potential therapeutic agent, SAM is being used as over the counter drug and nutrient supplement. An expression vector, harboring SAM synthetase 2 gene from S. cerevisiae and regulated by the glyceraldehyde-3-phosphate dehydrogenase gene promoter P(GAP), was transformed into GS115 strain of P. pastoris. Through zeocin resistance and expression screening, a recombinant strain was obtained that had high SAM yield and the fermentation conditions were optimized. The results showed that carbon source, nitrogen source, pH and dissolved oxygen had significant effects on the accumulation of SAM. The SAM production of the recombinant cells reached 2.49 g/L after fermentation for three days under the optimized conditions. The present studies show that fermentation of recombinant P. pastoris strain, expressing heterologous SAM synthetase gene, may be a promising approach for the production of SAM.

Bleomycin↗
PubMed2003

Purification and characterization of Alcaligenes faecalis penicillin G acylase expressed in Bacillus subtilis.

The Alcaligenes faecalis PGA gene encoding heterodimeric penicillin G acylase (PGA) was cloned and successfully expressed in Escherichia coli and Bacillus subtilis respectively. In contrast to E.coli hosts where the enzymes were retained in the periplasm, B. subtilis cell secreted the recombinant enzyme into the medium. Contrary to limited expression yield of E. coli (pETAPGA), PGA extracellularly expressed by B. subtilis (pBAPGA) and B. subtilis (pMAPGA) reached the highest yield of 653 u/L. This yield increased 109-fold higher than the native expression of A. faecalis CICC AS1.767. The enzyme was fractionated with (NH(4))(2)SO(4) and purified by DEAE-Sepharose CL-6B with a yield of 81%. The purified enzyme had a specific activity of 1.469 u/mg. Furthermore, some enzyme characteristics, such as the pH and temperature optimum, the stability against organic solvent and the ratio of cepholexin synthesis to hydrolysis were determined. By overexpressing A. faecalis PGA in B. subtilis and purifying secreted enzyme from culture medium one could readily obtain a large amount of an alternative source of PGA.

Alcaligenes↗