Biomedical subjects

Y H Zhou

Publications and source records attributed to Y H Zhou.

At least 19 recordsLinked to original sources

PubMed2006

Different effects of chilling on respiration in leaves and roots of cucumber (Cucumis sativus).

The effects of chilling on respiration (SHAM-resistant, cytochrome pathway and KCN-resistant, alternative pathway), temperature sensitivity, relative electrolyte conductivity, and degrees of oxidative stress (H(2)O(2) and malonaldehyde (MDA) contents) were separately examined in leaves and roots of cucumber (Cucumis sativus L.). After chilling at 8 degrees C for 4 days, both total respiration and KCN-resistant respiration in roots increased at different measurement temperatures. In contrast, SHAM-resistant respiration remained unchanged. In comparison, chilling significantly decreased the total respiration in leaves and this decrease was mostly due to a decrease in SHAM-resistant respiration. Chilling apparently decreased the sensitivity of KCN-resistant respiration to changes of temperature. The reduction levels of ubiquinone pool (UQr/UQt) increased both in chilled leaves and roots whilst pyruvate content increased only in chilled roots, but not in chilled leaves. Furthermore increases of H(2)O(2) and MDA contents were much greater in leaves than in roots. The same trend was also observed for ion leakage from tissues. Taken together, the results suggested that the higher chilling tolerance of roots was associated with their high total respiration and KCN-resistant respiration.

Cold Temperature↗

PubMed2004

Perceptual dominance time distributions in multistable visual perception.

Perceptual multistability, alternative perceptions of an unchanging stimulus, gives important clues to neural dynamics. The present study examined 56 perceptual dominance time series for a Necker cube stimulus, for ambiguous motion, and for binocular rivalry. We made histograms of the perceptual dominance times, based on from 307 to 2478 responses per time series (median=612), and compared these histograms to gamma, lognormal and Weibull fitted distributions using the Kolmogorov-Smirnov goodness-of-fit test. In 40 of the 56 tested cases a lognormal distribution provided an acceptable fit to the histogram (in 24 cases it was the only fit). In 16 cases a gamma distribution, and in 11 cases a Weibull distribution, were acceptable but never as the only fit in either case. Any of the three distributions were acceptable in three cases and none provided acceptable fits in 12 cases. Considering only the 16 cases in which a lognormal distribution was rejected ( p<0.05) revealed that minor adjustments to the fourth-moment term of the lognormal characteristic function restored good fits. These findings suggest that random fractal theory might provide insight into the underlying mechanisms of multistable perceptions.

Algorithms↗

PubMed2003

The application of a Pareto optimisation method in the design of an integrated bioprocess.

A rapid method for designing integrated bioprocesses, using a combination of a windows of operation and a Pareto optimisation approach, is described in this paper. Within bioprocesses, multiple objectives are common, and achieving a satisfactory trade-off amongst the design objectives is crucial. Conventional optimisation results in the identification of the best operating policy for a given desired performance but gives little insight into how the process performance changes in the vicinity of the solution. In this paper, we explore the use of a Pareto optimisation technique to locate the optimal conditions for an integrated bioprocessing sequence and the benefits of first reducing the feasible space by the development of a series of windows of operation to provide a smaller search area for the optimisation. The final results are then presented in performance trade-off graphs and look-up tables, which give the design engineer an easily manageable solution set to work with. In this way, the decision-making procedure for design is made faster and more transparent. Two case studies illustrate the results from this integrated design methodology, some of which are counter-intuitive compared with the general design experience.

Journal Article↗

PubMed2001

Graphical method for the calculation of chromatographic performance in representing the trade-off between purity and recovery.

A simple engineering framework that enables the rapid representation of the performance of liquid chromatographic separations is provided in this paper. The fractionation diagram and its associated maximum purification factor versus product yield, and contamination index versus product yield diagrams, may be derived directly from chromatographic data. The fractionation diagram plots the relative change in the cumulative fractional mass of product eluted with the corresponding fractional total mass eluted, while the maximum purification factor versus yield diagram shows the degree of trade-off between the levels of purity and recovery achieved in the chromatographic step. The minimum contamination index versus yield plot is especially suitable for cases where the product and impurity are expressed in different units and shows how the extent of contaminant removal changes relative to product yield. These diagrams are more straightforward and easily interpretable compared to the basic conventional chromatograms and enable investigation of the degree of trade-off between purity and recovery for any set of operating conditions to be made. The approach is demonstrated for two different chromatographic systems. In the first, a set of simulation results from a verified size exclusion model is used to demonstrate the approach for product recovery. In the second, a set of experimental results for the removal of endotoxin from DNA is used. This demonstrates a problem where the product and impurity content are measured by different assay techniques and are expressed in different units, and also where the quality of process information is limited by the small number of fractions collected. The studies show how such an approach can help to identify the optimal operating conditions, in terms of acceptable yield and desired level of contaminant removal, and to redefine the location of product fractions needed to achieve these specifications.

Algorithms↗

PubMed2001

Activation of the human PAX6 gene through the exon 1 enhancer by transcription factors SEF and Sp1.

PAX6 is a transcription factor that plays a major role in ocular morphogenesis. PAX6 is expressed in the eye, central nervous system and pancreas. Two alternative promoters, P0 and P1, which are differentially regulated during development, drive PAX6 transcription. We identified a 57 bp cis-regulatory element in exon 1 of the human PAX6 gene exon 1 enhancer (EIE). EIE enhances P1-driven PAX6 expression. Three regions in E1E (E1E-1, E1E-2 and E1E-3) have sequence similarities with binding sites of transcription factors ARP-1, Isl-1 and SEF, respectively. As shown by electrophoretic mobility shift assays, E1E-3, but not E1E-1 or E1E-2, bound to proteins in nuclear extracts of human glioma cells and transcription factor SEF bound to E1E-3. As shown by transient transfection experiments, deletion or site-specific mutations in E1E-3 dramatically decreased P1 promoter activity. Mutations in E1E-2, however, did not affect function of the P1 promoter. Co-transfection of SEF and PAX6 promoter-reporter constructs showed that SEF up-regulates PAX6 gene expression through the P1 promoter. Two Sp1 sites in the E1E region were also shown to be important by transient co-transfection assays. Data from immunoprecipitation and transient transfection assays demonstrated that SEF and Sp1 interacted in vitro and may act together in vivo to regulate PAX6 expression.

Base Sequence↗

PubMed2001

Tumorhead, a Xenopus gene product that inhibits neural differentiation through regulation of proliferation.

Tumorhead (TH) is a novel maternal gene product from Xenopus laevis containing several basic domains and a weak coiled-coil. Overexpression of wild-type TH resulted in increased proliferation of neural plate cells, causing expansion of the neural field followed by neural tube and craniofacial abnormalities. Overexpressed TH protein repressed neural differentiation and neural crest markers, but did not inhibit the neural inducers, pan-neural markers or mesodermal markers. Loss of function by injection of anti-TH antibody inhibited cell proliferation. Our data are consistent with a model in which tumorhead functions in regulating differentiation of the neural tissues but not neural induction or determination through its effect on cell proliferation.

Amino Acid Sequence↗

PubMed2001

Patient satisfaction following orthognathic surgical correction of skeletal Class III malocclusion.

The objectives of this study were to evaluate the relationship between preoperative psychologic status and attitude and postsurgical adjustment and experience of the surgical treatment. Questionnaires were sent to 140 consecutive Chinese patients with skeletal Class III malocclusion who had been treated with a combined orthodontic-surgical approach. The results showed the following: (1) immediately after the surgery 44% of patients had more pain, 57% had more numbness, and 73% had more swelling than expected; (2) most patients underwent noted marked changes in facial appearance (96%) and dental appearance (91%); (3) chewing ability improved in 71% of patients; (4) half of those with temporomandibular joint problems preoperatively experienced improvement; (5) personality and lifestyle were affected positively in about 50% of patients; (6) satisfaction with the treatment increased with time: 87% at 6 months and 92% at 24 months; and (7) a few patients (8%) regretted having undergone surgery, mainly because facial changes were not apparent. The vast majority of the present Chinese skeletal Class III patients were satisfied with the overall outcome of the continued orthodontic-surgical treatment.

Attitude to Health↗

PubMed2001

Concerns and motivations of skeletal Class III patients receiving orthodontic-surgical correction.

The objective of this research was to study the impact of skeletal Class III malocclusion on patients' emotional status, as well as patients' motivations for seeking surgical correction of Class III malocclusion. The sample comprised 140 consecutive Chinese patients with skeletal Class III malocclusion who had been treated with a combined orthodontic-surgical approach. A retrospective analysis was performed, based on questionnaires with answers ranked on a numeric scale (O = not at all; 1 = a little; 2 = moderately; 3 = quite a bit; 4 = extremely). Sixty-seven percent of subjects (40 males and 54 females) returned completed questionnaires. Fifty-four percent had bimaxillary deformities, 32% had mandibular hyperplasia, and 14% had maxillary hypoplasia. Seventy-seven percent received bimaxillary surgery, 15% received maxillary advancement, and 8% received mandibular setback. The results showed that nearly half of the patients had a nickname related to their dentofacial problems, and 8 of 10 of these felt embarrassed or angry about their nickname. Ninety-three percent sought improvement of their facial appearance, 85% wanted an improvement in their dental appearance, and 73% desired an improvement in chewing ability. Seventy-six percent were concerned about surgical risks and 63% about possible pain. The vast majority of Class III patients undergoing orthognathic surgery suffered psychologic and functional problems related to their appearance prior to treatment. Esthetic improvement was the driving force behind seeking treatment.

Adolescent↗

PubMed2001

[Determination of fatty acids in Malania oleifera oil by gas chromatography-mass spectrometry].

Fatty acids in the Malania oleifera oil of Yunnan were esterified by sulfuric acid-methanol and analyzed by GC-MS. Seventeen components were separated and seven acids as methylesters were identified and determined. They were hexadecanoic acid (1.50%), 9c-octadecenoic acid (21.54%), 11c-eicosenoic acid (7.04%), 13c-docosenoic acid (18.29%), docosanoic acid (1.33%), 15c-tetracosenoic acid (40.92%), tetracosanoic acid (2.14%). There were 7.24% components unidentified.

Fatty Acids↗

PubMed2001

[Analysis of main chemical composition in hydrogenated rosin from Zhuzhou].

The acid fraction, the main part of the hydrogenated rosin produced by Zhuzhou Forest Chemicals Plant of China, was separated from neutral fraction by modified DEAE-Sephadex ion exchange chromatography and analyzed with GC-MS-DS technique by using DB-5 capillary column. Six dihydroabietic-type resin acids, four dihydropimaric/isopimaric-type resin acids and four tetrahydroabietic-type resin acids were identified. The hydrogenated rosin is composed mainly of 8-abietenoic acid, 18-abietanoic acid, 13-abietenoic acid, 8 alpha, 13 beta-abietanoic acid, 13 beta-8-abietenoic acid and 8-isopimarenoic acid etc.

Carboxylic Acids↗

PubMed2001

[Twelve cases of malignant hematopathy treated by combined therapy of hematopoietic stem cell transplantation and Chinese herbal medicine].

OBJECTIVE: To evaluate the effect of hematopoietic stem cell transplantation combined with Chinese herbal medicine in treating malignant hematopathy. METHODS: Allo-bone marrow transplantation (Allo-BMT) or alloperipheral blood stem cell transplantation (Allo-PBSCT), with conditioning regimen of TBI + Cy or Bu + Cy, was used to treat 4 cases of chronic granulocytic leukemia (CGL, 3 of chronic phase and 1 of acceleration phase) and one case of acute non-lymphocytic leukemia (ANLL). And auto-BMT or auto-PBSCT, with conditioning regimen of MAC or MAC + VP16, was used to treat 7 cases of hematopathy, including 5 cases of ANLL (3 of CR1 and 2 of CR2) and 2 cases of malignant lymphoma (1 of first occurring and 1 of relapse). Chinese herbal medicine was given orally to all the 12 patients after' transplantation according to TCM Syndrome Differentiation. RESULTS: All patients were successfully engrafted. Within the median follow-up period of 18 (4-70) months, one patient (8.3%) died of transplantation-related death, 3(25.0%) relapsed and 8 (66.7%) survived free of original disease. The transplantation effective rate was 88.8% as counting by ANLL CR1 and CGL chronic phase. CONCLUSION: Auto-BMT or auto-PBSCT in CR1 stage of acute leukemia could reduce the relapse rate, when there was no matched bone marrow donor; allo-BMT or allo-PBSCT in chronic stage could result in long-term disease-free survival of patients; Chinese herbal medicine administration in patients of malignant hematopathy might reduce the complications and plays certain role in promoting recovery of hematopoietic function.

Adolescent↗

PubMed2000

[Expression of bcl-2 in acute leukemia patients and its significance].

UNLABELLED: RT-PCR method was used to detect the expression level of bcl-2 gene in 38 patients of acute leukemia. RESULTS: Expression level of bcl-2 in the patients with clinical refractoriness increased more obviously than previously untreated and CR patients, and the expression level of bcl-2 was obviously correlated with clinical refractoriness(r = 0.83, P < 0.01), which indicated that high expression of bcl-2 was one of the factors in clinical refractoriness. It was also a sensitive method for predicting the effect of anti-tumor agents and prognosis in clinic work.

Adolescent↗

PubMed2000

Monoclonal antibodies to the hypervariable region 1 of hepatitis C virus capture virus and inhibit virus adsorption to susceptible cells in vitro.

To analyze the neutralizing-related activity of antibodies against the hypervariable region 1 (HVR1) of hepatitis C virus (HCV) in more detail, monoclonal antibodies (mAbs) against HVR1 were raised by immunizing various strains of mice with one of two synthetic HVR1 peptides that had been derived from two isolates of HCV. The epitope specificity of all six mAbs could be assigned by the use of a series of linear peptides in competitive ELISA. It seems that most subregions in the amino acid sequence of HVR1 can induce a humoral immune response in mice. All three mAbs specific to HVR1-6-1 had the ability to capture homologous HCV-6 and inhibit its absorption to susceptible cells in vitro despite the fact that the epitope of each mAb was at a different location in HVR1, whereas the other three mAbs specific to HVR1-7 could not capture HCV-6 nor inhibit the absorption of HCV-6 to susceptible cells. The data in this study suggest that mAbs against HVR1 can prevent the infectivity of HCV in an isolate-specific and epitope position-independent manner.

Adsorption↗

PubMed2000

Effects of interleukin-1 blockers on corneal fibroblast proliferation in vitro and ocular inflammation in vivo.

The success of keratorefractive surgical procedures is limited by the wound healing process in the corneal stroma. The proliferation and matrix synthesis of corneal stromal fibroblasts is the central element of the wound healing process that is triggered by an initial inflammation. In order to develop new therapeutic strategies to reduce wound healing intensity, we investigated the effect of newly synthesized interleukin-1 (IL-1) blockers on the proliferation of cultured rabbit corneal fibroblasts and the ocular inflammation induced by IL-1. It was found that the addition of IL-1 blockers, such as CK-135 to CK-145, led to a dose-dependent inhibition of cell proliferation after 24, 48 and 72 hr of incubation. The isotope incorporation study showed that the syntheses ofDNA and mRNA were suppressed whereas that of protein was enhanced or unaffected. These compounds also demonstrated a potent anti-inflammation action in the rat uveitis model. Our results indicate that CK (Chiou-Kumamoto) compounds may be valuable therapeutic agents for the prevention of postoperative complications after corneal keratorefractive surgical procedures.

Animals↗

PubMed1999

Visualizing integrated bioprocess designs through "windows of operation".

This paper demonstrates a simple graphical approach for the design and analysis of a bioprocess flowsheet in which process interactions are significant. Results are presented showing how the feasible space for operation can be simulated and used both to address key design and operating decisions and to identify suitable trade-offs between operating variables, such as fermentation growth rate and disruption conditions, in order to achieve prespecified levels of process performance. Using verified models to describe the production and isolation of an intracellular protein alcohol dehydrogenase (ADH) in yeast as a test bed, a series of so-called "windows of operation" are developed at growth rates in the range of 0.06-0.28 h(-1) and for a range of overall process specifications. The effects of altering the process design performance specification as defined by the level of cell debris removal and the overall process productivity on the size and position of the feasible space were investigated to demonstrate the sensitivity of the flowsheet to changes in process objectives. Using the approach it has been possible to visualise the processing trade-offs required to increase performance in terms of the level of cell debris removal by 50% and the overall process productivity by 400% from a defined base level. The approach provides a convenient tool when designing integrated bioprocesses by enabling process options to be compared visually and can help in achieving better process designs and accelerating process development for the biological process industry.

Alcohol Dehydrogenase↗

PubMed1999

Multiple sequence-reactive antibodies induced by a single peptide immunization with hypervariable region 1 of hepatitis C virus.

Hypervariable region 1 (HVR1) of hepatitis C virus (HCV) is known to contain neutralizing epitopes. We previously found that murine antibodies against HVR1-#6 captured a different isolate, HCV-#7, and cross-reacted with the HVR1 peptide of HCV-#7. We investigated the inducibility and generality of cross-reaction of animal anti-HVR1 antibody responses in this study. Anti-HVR1-#7 antibodies, which were induced in mice and a chimpanzee by immunization, were found to be cross-reactive to HVR1-#6 peptide. Antibody responses against HVR1-#6-1 and HVR1-#7 peptides were detected in 11/165 (6.7%) and 26/165 (15.8%) HCV-infected individuals, respectively. Nine HVR1 sequences from six individuals, who were strongly positive for anti-HVR1-#7 antibodies, were only 50-64.5% identical to that of HVR1-#7. All nine of these HVR1 peptides were reactive to sera from the six patients and/or to antisera against HVR1-#6 and HVR1-#7 produced in mice and chimpanzees. Cross-inhibition tests of chimpanzee antisera indicated that a given species of anti-HVR1 antibodies was reactive to multiple HVR1 sequences. Fine epitope mapping of polyclonal and monoclonal anti-HVR1 antibodies showed that conserved subregions in HVR1 sequences determined the observed immunological cross-reactivity. Our data demonstrate that cross-reacting anti-HVR1 antibodies are inducible by a single peptide immunization.

Amino Acid Sequence↗

PubMed1999

Markers in the promoter region of interleukin-10 (IL-10) gene in myasthenia gravis: implications of diverse effects of IL-10 in the pathogenesis of the disease.

Interleukin-10 (IL-10) is an important pleiotropic cytokine with both anti-inflammatory and B lymphocyte stimulating functions. The expression of IL-10 is tightly controlled. A bi-allelic polymorphism and 2 CA repeat microsatellites located in the promoter region of IL-10 gene were analysed in Swedish myasthenia gravis (MG) patients and ethnically matched healthy individuals. The prevalence of a 'high secretor' phenotype of IL-10 (IL-10 1 G/G) was higher in IL-1beta TaqI polymorphism allele 2 positive healthy individuals ('high secretor' phenotype for IL-1beta) than in healthy individuals negative for this allele. No such balance was found in MG patients. In one of the microsatellites, IL10.R, allele 112 was associated with patients having normal thymic histology. No relation of IL10.R allele 112 to proinflammatory cytokine gene polymorphisms and serum IgG, IgM and autoantibodies against nicotinic acetylcholine receptor (nAchR-Ab) was found. In another microsatellite, IL10.G, allele 134 was associated with patients having higher level of nAchR-Ab in their circulation. Our results demonstrated novel genetic markers within IL-10 gene indicating different mechanisms for IL-10 involved in the disease.

Alleles↗

PubMed1999

Experimental vaccine activities of recombinant E1 and E2 glycoproteins and hypervariable region 1 peptides of hepatitis C virus in chimpanzees.

A chimpanzee was immunized with two recombinant envelope glycoproteins E1 and E2 of hepatitis C virus (HCV), strain HCV-N2, and the hypervariable region 1 (HVR1) peptides of a different isolate, HCV-#6, then received an intravenous inoculation of 10 chimpanzee infectious doses of HCV-#6. With high humoral immune response against E1 and E2 but a low response against HVR1, the vaccinee became infected with the HCV. However, after increasing the titer of anti-HVR1 against HCV-#6, the vaccinee showed protection. Neutralization of HCV-#6 with the antiserum from this protected vaccinee was achieved by inoculation of this mixture into another chimpanzee. These results suggest that vaccination with a peptide-vaccine of homologous HVR1 is effective in the chimpanzee.

Amino Acid Sequence↗