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Biomedical subjects

Ying Han

Publications and source records attributed to Ying Han.

At least 73 records · Page 4Linked to original sources
PubMed2004

Anticancer effect of two diterpenoid compounds isolated from Annona glabra Linn.

AIM: To study the inhibitory effect of two diterpenoid compounds isolated from Annona glabra Linn (Cunabic acid and ent-kauran-19-al-17-oic acid) on the proliferation of Human Liver Cancer (HLC) cell line SMMC-7721 and its mechanism. METHODS: Inhibition of cell proliferation was measured by MTT assay. The morphological changes of SMMC-7721 cells were observed under inverted phase-contrast microscope, fluorescent microscope, transmission electron microscope (TEM), and scanning electron microscope (SEM). Flow cytometer (FCM) was used to calculate the cell apoptotic rate, and immunohistochemical staining was used to observe the regulation of gene expression. RESULTS: The proliferation of SMMC-7721 cells was obviously inhibited after being treated with Cunabic acid at the concentration great than 5 micromol/L and ent-kauran-19-al-17-oic acid great than 10 micromol/L. The biggest inhibitory effect was 81.05% when treated with Cunabic acid at the concentration of 25 micromol/L. The effect had a linear relationship with concentration. The result indicated that drug-treated cells exhibit typical morphological changes of apoptosis, including condensed chromatin and a reduction in volume. Sub-G0/G1 peak was found by FCM analysis and the cell cycle was arrested at G0/G1 stage. The apoptotic rates of the cells treated by Cunabic acid and ent-kauran-19-al-17-oic acid were 43.31% and 24.95%, respectively. It was visualized by immunohistochemical staining that the drugs down-regulated the gene expression of bcl-2 gene and up-regulated that of bax gene. CONCLUSION: The two diterpenoid compounds isolated from Annona glabra Linn, Cunabic acid and ent-kauran-19-al-17-oic acid can obviously inhibit the proliferation of HLC cell line SMMC-7721. The mechanism is correlated with the induction of cell apoptosis by down-regulating the gene expression of bcl-2 gene and up-regulating that of bax gene.

Annona↗
PubMed2004

[Effect of pre-freezing temperature and lyophilizer shelf temperature on recovery of red blood cells after lyophilization].

To study effect of pre-freezing temperature and lyophilizer shelf temperature on recovery of human red blood cells after lyophilization and determine solidifying temperature of this lyophilization system, the protective solution composed of 7% DMSO, 40% polyvinylpyrrolidone (PVP) and isotonic buffer were adopted to lyophilize red blood cells at different pre-freezing temperatures or shelf temperatures. At first, fresh whole blood was centrifugated, washed and equilibrized to prepare concentrated red blood cells. Then concentrated red blood cells were mixed with the protective solution at 1:3 and pre-freezed at different temperature (-20, -35, -45, -80 or -196 degrees C) before lyophilization in lyophilizer. To study effect of shelf temperature on lyophilization of red blood cells, red blood cells were lyophilized at different shelf temperature after pre-freeze at -80 degrees C. After lyophilization, the samples were quickly rehydrated by 37 degrees C rehydration solution. The results showed the recovery rate of red blood cells and hemoglobin after pre-freeze at different temperature and lyophilization were > 85% and > 75%, there was not significant difference among these groups, but the concentration of free hemoglobin in -196 degrees C group was significantly higher than that in other groups (P < 0.01). With decreasing of shelf temperature, the lyophilizing time was also prolonged. When shelf temperature was > or = -25 degrees C, samples were not fully lyophilized; when shelf temperature was < or = -30 degrees C, the recovery rate of red blood cells and hemoglobin after lyophilization and rehydration were above 90%; after washed to isotonic state, the recovery rate of hemoglobin of the four groups was similar to each other. In conclusion, only when pre-freezing temperature is between -20 and -80 degrees C and the lyophilizer shelf temperature is < or = -30 degrees C, the effect of lyophilization is better, but the effect of excessively low pre-freezing temperature may even be worse.

Blood Preservation↗
PubMed2004

[Platelet activation through signal transduction--review].

Platelet is activated through signal transduction, that mainly includes phospholipase-beta (PLCbeta) pathway, protein tyrosine kinases (PTK) pathway, phosphatidylinositol3-kinase (PI3-K) pathway, mitogen-activated protein kinases (MAPK) pathway, cyclic adenosine monophosphate-protein kinase A (cAMP-PKA) pathway and phospholipase A2 (PLA2) pathway. This article focuses on the relationship between signal transduction and platelet activation.

Calcium↗
PubMed2004

AT1 receptor in rostral ventrolateral medulla mediating blunted baroreceptor reflex in spontaneously hypertensive rats.

AIM: To determine the role of AT1 receptor in the rostral ventrolateral medulla (RVLM) in mediating the blunted baroreceptor reflex in spontaneously hypertensive rats (SHR). METHODS: Intravenous injections of graded doses of phenylephrine (1, 5, 10, 20, and 40 microg/kg) increased the blood pressure to elicit the baroreceptor reflex in both SHR and normotensive Wistar rats anesthetized with urethane. The baroreceptor reflex sensitivity (BRS) was determined before and after microinjection of Ang II, losartan, or AT1 receptor antisense oligodeoxynucleotides into the RVLM. AT1 receptor protein level in the RVLM was measured by Western blotting. RESULTS: The BRS was significantly decreased in SHR compared with normal rats. Bilateral microinjection of AT1 receptor antagonist losartan (250 nmol/h) into the RVLM partly reversed the blunted BRS in SHR, but had no significant effect on the BRS in normal rats. Ang II (1.5 nmol/h) significantly inhibited the BRS in normal rats, which was completely abolished by pretreatment with losartan. However, no significant change in the BRS was observed after microinjection of Ang II into the RVLM in SHR. Bilateral microinjection of AT1 receptor antisense oligodeoxynucleotides (ASODN) into the RVLM partially recovered the blunted BRS in SHR after 3 h, but no significant change in the BRS was observed in normal rats. The AT1 receptor protein level significantly decreased after administration of ASODN. CONCLUSION: Blockage of AT1 receptor or inhibition of AT1 receptor protein synthesis in the RVLM enhanced the BRS in SHR, suggesting that the enhanced activities of AT1 receptor in the RVLM contribute to the blunted BRS in SHR.

Angiotensin II↗
PubMed2004

[Isolation and identification of minor bioactive saponins from the leaves of Panax notoginseng].

The minor bioactive saponins of the total saponin from the leaves of Panax notoginseng (Burk.) F. H. Chen. were separated and purified by column chromatographies on silica gel and thin layer gel. Four compounds were identified as: ginsenoside C-K (I) [20 (S) -protopanaxadiol 20-O-beta-D-glucopyranoside], ginsenoside-Rh1 (II) [20 (S) -protopanaxatriol-6-O-beta-D-glucopyranoside], ginsenoside-Mc (III) [20 (S)-protopanaxadiol 20-O-alpha-L-arabinofuranosyl (1 --> 6) -D-glucopyranoside] and notoginsenoside-Fe (IV) [20(S) -protopanaxadiol-3-O-beta-D-glucopyranosido-20-O-alpha-L-arabinofuranosyl(1 --> 6)-beta-D-glucopyranoside]. Compound I was isolated from the leaves of Panax notoginseng for the first time.

Chromatography, Thin Layer↗
PubMed2003

[Effects of recurrent febrile seizures on gamma-aminobutyric acid B receptor subunit expressions in the hippocampus of developing rats].

OBJECTIVE: To study gamma-aminobutyric acid (GABA) B receptor subunits GABABR1 and GABABR2 protein expression changes after recurrent febrile seizures in the hippocampus of developing rats. METHODS: The rats were randomly divided into hyperthermia-treated group (n = 68) and control group (n = 24). According to the times of treatment, and to whether seizures developed, hyperthermia-treated group were subdivided into 4 groups: F1 (febrile, one-time, n = 12), FS1 (febrile seizure, one-time, n = 16), F10 (febrile, ten-time, n = 13), FS10 (febrile seizure, ten-time, n = 15). Immunohistochemical staining was used to demonstrate GABABR1 and GABABR2 expressions in brain sections (12 microns each). RESULTS: GABABR1 and GABABR2 protein expressions significantly decreased in dentate gyrus and CA1-CA3 neurons in FS10 compared with those in F10, F1, FS1 and control groups. The expressions of GABABR1 and GABABR2 protein showed less intense in F10 than those in FS1, F1 and control groups. No significant differences were observed among F1, FS1 and control group. Throughout the hippocampus, the expressions of GABABR1 and GABABR2 protein largely overlaped. GABABR1 protein expressions decreased seriously as compared with the expressions of GABABR2 protein in dentate gyrus, whereas GABABR2 protein expressions decreased more apparently in hippocampus CA1 and CA3 than that of GABABR1 in FS10. CONCLUSION: Recurrent febrile seizures and recurrent hyperthermia all can make the GABABR receptor protein expression down-regulated in the immature rat brain, and GABABR protein expression decreased more apparently in recurrent febrile seizure groups than that in recurrent hyperthermia groups. These suggest that GABABR subunits may play an important role in the immature rat febrile seizures and the difference between GABABR1 and GABABR2 protein expression changes is possible as a result of subunit reorganization, which may lead to the changes of the inhibitory function.

Animals↗
PubMed2003

Determination of ketotifen and its conjugated metabolite in human plasma by liquid chromatography/tandem mass spectrometry: application to a pharmacokinetic study.

A sensitive and specific liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the investigation of the pharmacokinetics of ketotifen and its major metabolite, ketotifen N-glucuronide, in human plasma. The plasma samples were treated by liquid-liquid extraction and analyzed using LC/MS/MS with an electrospray ionization interface. Diphenhydramine was used as the internal standard. The method had a lower limit of quantitation of 10 pg/mL for ketotifen, which offered increased sensitivity, selectivity and speed of analysis, compared with existing methods. The intra- and inter-day precision were measured to be below 8.2% and accuracy between -2.4% and 3.4% for all QC samples. Incubation of the plasma samples with beta-glucuronidase allowed the quantitation of ketotifen N-glucuronide. This quantitation method was successfully applied to a pharmacokinetic study of ketotifen and its major metabolite after oral administration of 2 mg ketotifen fumarate to 16 healthy volunteers.

Adult↗
PubMed2003

Determination of carbocysteine in human plasma by liquid chromatography/tandem mass spectrometry employing precolumn derivatization.

A sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed to determine carbocysteine in human plasma using 2-pyridylacetic acid as the internal standard (IS). The method employed derivatization with 10 M hydrochloric acid/methanol, which significantly improved the ionization efficiency of carbocysteine. After methanol-induced protein precipitation of plasma samples, carbocysteine and the IS were derivatized and subjected to LC/MS/MS analysis using atmospheric pressure chemical ionization. The method has a lower limit of quantitation of 20 ng/mL for a 0.2-mL plasma aliquot. The intra- and inter-day precision (RSD), calculated from quality control (QC) samples, was less than 7%. The accuracy, determined using QC samples, was within +/- 1%. The method offered increased sensitivity, selectivity and speed of analysis over existing methods. The method was utilized to support clinical pharmacokinetic studies of carbocysteine in volunteers following oral administration.

Calibration↗
PubMed2003

Immobilized peptides as high-affinity capture agents for self-associating proteins.

There is currently great interest in the fabrication of protein-detecting arrays comprised of large numbers of immobilized protein capture agents. While most efforts in this arena have focused on the use of biomolecules such as antibodies and nucleic acid aptamers as capture agents, synthetic species have many potential advantages. However, synthetic molecules isolated from combinatorial libraries generally do not bind target proteins with the high affinity necessary for array applications. Here, we demonstrate that simple linear peptides bind dimeric proteins tenaciously when immobilized, although they exhibit only modest affinity in solution. These data show that high-affinity bidentate capture agents for dimeric proteins can be created by simply immobilizing modest-affinity ligands on a surface at high density, bypassing the requirement for careful optimization of linker length and geometry that is normally required to create a high-affinity solution bidentate ligand.

Combinatorial Chemistry Techniques↗
PubMed2003

Static aspects of eye and head movements during reading in a simulated computer-based environment with single-vision and progressive lenses.

PURPOSE: Reading with two different intermediate progressive lens designs was investigated regarding eye and head movement patterns and compared with movement patterns with a conventional single vision lens in a computer-based work environment. METHODS: Two-dimensional eye (horizontal, vertical) and three-dimensional head (horizontal, vertical, and torsional) movements were recorded objectively and simultaneously at a rate of 60 Hz during reading of moderate contrast (40%) single- and double-page text formats at 60 cm with binocular viewing. In addition, global reading ability was rated subjectively for each lens. Subjects were 11 visually normal, presbyopic individuals aged 45 to 71 years selected by convenience sampling from a clinic population. Reading was performed with three types of spectacle lenses: a single-vision lens (SVL; 60 degrees horizontal [H] clear field-of-view [FOV]); a progressive addition lens (PAL) with a relatively wide intermediate zone (PAL-I; 7.85 mm, 18 degrees H clear FOV); and a PAL with a relatively narrow intermediate zone (PAL-II; 5.60 mm, 13 degrees H clear FOV). RESULTS: Many reading-related parameters, as well as eye- and head-movement parameters, were adversely affected by the PALs compared with the SVL. One reading-related parameter (i.e., number of regressions) differentiated between PALs. Subjective rating of global reading ability was highest with the SVL and lowest with the PAL-II. CONCLUSIONS: The optical design of a spectacle lens had significant impact on reading performance and on the combined eye-head movements initiated during reading. Both horizontal eye and head movements discriminated well between PALs and the SVL, but not between PALs, despite subjective preferences. This suggests that nonoculomotor factors contribute to patients' nonacceptance of PALs. Vertical eye and head movements and torsional head movements were not as discriminatory as were their horizontal counterparts.

Aged↗
PubMed2003

Dynamic interactions of eye and head movements when reading with single-vision and progressive lenses in a simulated computer-based environment.

PURPOSE: To assess dynamic interactions of eye and head movements during return-sweep saccades (RSS) when reading with single-vision (SVL) versus progressive-addition (PAL) lenses in a simulated computer-based business environment. METHODS: Horizontal eye and head movements were recorded objectively and simultaneously at a rate of 60 Hz during reading of single-page (SP; 14 degrees horizontal [H]) and double-page (DP; 37 degrees H) formats at 60 cm with binocular viewing. Subjects included 11 individuals with normal presbyopic vision aged 45 to 71 years selected by convenience sampling from a clinic population. Reading was performed with three types of spectacle lenses with a different clear near field of view (FOV): a SVL (60 degrees H clear FOV), a PAL-I with a relatively wide intermediate zone (7.85 mm; 18 degrees H clear FOV), and a PAL-II with a relatively narrow intermediate zone (5.60 mm; 13 degrees H clear FOV). RESULTS: Eye movements were initiated before head movements in the SP condition, and the reverse was found in the DP condition, with all three lens types. Duration of eye movements increased as the zone of clear vision decreased in the SP condition, and they were longer with the PALs than with the SVL in the DP condition. Gaze stabilization occurred later with the PALs than with the SVL in both the SP and DP conditions. The duration of head movements was longer with the PAL-II than with the SVL in both the SP and DP conditions. Eye movement peak velocity was greater with the SVL than the PALs in the DP condition. CONCLUSIONS: Eye movement and head movement strategies and timing were contingent on viewing conditions. The longer eye movement duration and gaze-stabilization times suggested that additional eye movements were needed to locate the clear-vision zone and commence reading after the RSS. Head movements with PALs for the SP condition were similarly optically induced. These eye movement and head movement results may contribute to the reduced reading rate and related symptoms reported by some PAL wearers. The dynamic interactions of eye movements and head movements during reading with the PALs appear to be a sensitive indicator of the effect of lens optical design parameters on overall reading performance, because the movements can discriminate between SVL and PAL designs and at times even between PALs.

Aged↗
PubMed2003

Screening and identification of mimotope of gastric cancer associated antigen MGb1-Ag.

AIM: Using a monoclonal antibody against gastric cancer antigen named MGb1 to screen a phage-displayed random peptide library fused with coat protein pIII in order to get some information on mimotopes. METHODS: Through affinity enrichment and ELISA screening, positive clones of phages were amplified. 10 phage clones were selected after three rounds of biopanning and the ability of specific binding of the positive phage clones to MGb1-Ab were detected by ELISA assay (DNA sequencing was performed and the amino acid sequences were deduced) By blocking test, specificity of the mimic phage epitopes was identified. RESULTS: There were approximately 200 times of enrichment about the titer of bound phages after three rounds of biopanning procedures. DNA of 10 phage clones after the third biopanning was assayed and the result showed that the positive clones had a specific binding activity to MGb1-Ab and a weak ability of binding to control mAb or to mouse IgG. DNA sequencing of 10 phage clones was performed and the amino acid sequences were deduced. According to the homology of the amino acid sequences of the displayed peptides, most of the phage clones had motifs of H(x)Q or L(x)S. And these 10 phage clones could also partly inhibit the binding of MGb1-Ab to gastric cancer cell KATO-III. The percentage of blocking was from (21.0+/-1.6) % to (39.0+/-2.7) %. CONCLUSION: Motifs of H(x)Q and L(x)S selected and identified show a high homology in the mimic epitopes of gastric cancer associated antigen. There may be one or more clones which can act as candidates of tumor vaccines.

Animals↗
PubMed2003

[Analysis on ultrastructure of lyophilized red blood cells].

The objective of the present study was designed to evaluate lyophilized red blood cells of the ultrastructure. Blood was drawn from healthy adult. In group 1, sample was fresh blood; in group 2, sample was added 35% glycerine, stored at -80 degrees C for 24 hours; in group 3, red blood cells stored at 4 degrees C for 5 hours, then were lyophilized for 16 hour. The sample was resuspended for measurements of count and electron microscopy study. The result showed that lyophilized red blood cells possessed relative integrated structure, red blood cell recovery was 53%. The mean diameter, optical density and integral optical density of red blood cell were 4.7 +/- 0.4, 0.14 +/- 0.03 and 1.58 +/- 0.46 in group 1; 4.6 +/- 0.7, 0.14 +/- 0.02 and 2.35 +/- 0.64 in group 2; 4.4 +/- 0.4, 0.17 +/- 0.05 and 2.35 +/- 0.46 in group 3, respectively. There was no significant difference in lyophilized and frozen group, but there was significant difference in lyophilized group and normal group. In conclusion, human red blood cells could be successfully lyophilized and possess relative integrated structure. The mean diameter, optical density and integral optical density of lyophilized red blood cells were similar to that of cryopreservation red cells.

Blood Preservation↗
PubMed2003

[Determination of total lovastatin in red rice].

In order to text effectiveness and safety of red rice products, the determination of total lovastatin is more optional than that of determination of its lactone only. The method for determination of total lovastatin is established in this study. HPLC method is applied with the C18 column (250 mm x 4.60 mm). Flow phase: water (72:28); wave length: 238 nm; Flow speed: 1.0 ml/min; column temperature: room temperature. Moreover, the reliability of this method validated recovery rate 98.3, RSD = 0.33%.

Chromatography, High Pressure Liquid↗
PubMed2003

[Effect of vitrification state of protective solutions on recovery of red blood cells after lyophilization preservation].

To study effect of vitrification state of protective solutions on recovery of red blood cells after lyophilization, four protective solutions composed of isotonic buffers containing 7% DMSO (v/v) and 20%, 30%, 40% or 50% polyvinylpyrrolidone (PVP) (w/v) were adopted. Vitrification state of protective solutions was examined first when white ice crystal appeared in any protective solution during freezing or thawing, if the used solution was not a vitrification solution. Red blood cells were lyophilized in MINILYO45 freeze-dryer after washing, mixing with protective solutions and prefreezing. After lyophilization, the samples were quickly rehydrated by 37 degrees C rehydration solution. The results showed that in vitrification and devitrification experiments, white ice crystal appeared in solution of 20% PVP + 7% DMSO and 30% PVP + 7% DMSO during freezing and thawing; vitrification appeared in solution of 40% PVP + 7% DMSO during freezing, but devitrification appeared during thawing; vitrification appeared in solution of 50% PVP + 7% DMSO during freezing and thawing. After rehydration, the recoveries of red blood cells and hemoglobin in 40% PVP + 7% DMSO group were (81.36 +/- 14.94)% and (77.54 +/- 12.86)%, which were significantly higher than that in 20% PVP + 7% DMSO, 30% PVP + 7% DMSO and 50% PVP + 7% DMSO groups (P < 0.01). The concentration of free hemoglobin in 40% PVP + 7% DMSO group was also significantly lower than that in other three groups (P < 0.01). With increase of PVP concentration in protective solutions, vitrification state and protective effect of these solutions also increased; when concentration of PVP in protective solution was 40% though it was not a vitrification solution, the effect of lyophilization was the best; but when concentration of PVP further increased to 50%, though it was a vitrification solution, the effect decreased. It is concluded that excessive vitrification state could not benefit lyophilization of red blood cells.

Cryoprotective Agents↗
PubMed2003

[Dynamic changes of ultrastructure of erythrocytes in prolonged preservation at 4 degrees C].

To study the dynamic changes of ultrastructure of erythrocytes in prolonged preservation of blood with preservative fluid containing superoxide dismutase (SOD), the whole blood samples were preserved at 4 degrees C in SOD-containing solution, the morphologic changes of erythrocyte were dynamically ob served by transmission microscopy after preservation for 42, 75 and 85 days, an d the blood samples preserved in GMA solution served as control. Three variance was applied to analyze the data with SAS software. The results showed that the metamorphotic rates of erythrocyte preserved in SOD-containing solution for 42, 75 and 85 days were lower than those of erythrocytes preserved in GMA solution. Most of metamorphotic rates of erythrocyte preserved in SOD-containing solution for 42, 75 and 85 days were correspond to those of erythrocytes preserved in GMA solution for 42 days, or even lower. It is concluded that SOD-containing preservative fluid might help to maintain the normal morphology of erythrocytes in prolonged preservation at 4 degrees C.

Blood Preservation↗