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Biomedical subjects

Fang Wang

Publications and source records attributed to Fang Wang.

At least 235 records · Page 13Linked to original sources
PubMed2003

Elimination of interference information by a new hybrid algorithm for quantitative calibration of near infrared spectra.

A new hybrid algorithm is proposed to eliminate the interference information for multivariate calibration of near-infrared (NIR) spectra that includes noise, background and systemic spectral variation irrelevant to concentration. The method consists of two parts: approximate derivative based on continuous wavelet transform (CWT) and orthogonal signal correction (OSC). After the approximate derivative calculated by CWT, OSC was performed. It was successfully applied to real complex NIR spectral data to eliminate the interference information. Correction for the interference of NIR spectra resulted in a substantial improvement in the predicted precision, and a more concise calibration model was obtained. The proposed procedure also compared favourably with several pretreatment methods, and the new method appears to provide a high-performance pretreatment tool for multivariate calibration of NIR spectra. In addition, the strategy proposed here can be applied to various other spectral data for quantitative purposes as well.

Journal Article↗
PubMed2003

Anti-invasion and anti-angiogenesis effect of taxol and camptothecin on melanoma cells.

Two highly invasive melanoma cell lines B16BL6 and B16F10 were used to investigate the anti-invasion and antiangiogenesis action of taxol and camptothecin (CPT). The adhesion of melanoma cells was tested by optical absorbance at 545 nm. The invasive activity of these cells was tested in a transwell chamber assay. The cell migration within a 3D collagen matrix was recorded with a time-lapse video recorder and analyzed by computer-assisted cell tracking. Gelatin zymography was used to study the metalloproteinase activity. The chicken chorioallantoic membrane (CAM) model was used to study the anti-angiogenesis effect of the two drugs. The results demonstrated that both taxol and CPT could inhibit the migration of B16F10 cells, and inhibit the adhesion of B16F10 to fibronectin and laminin. They can reduce the metalloproteinase secretion of HT1080 and exhibit the antiangiogenesis effect in the CAM model. Taxol showed a highly anti-invasion effect on B16BL6 cells while CPT did not exhibit such an effect.

Animals↗
PubMed2003

Caenorhabditis elegans EVL-14/PDS-5 and SCC-3 are essential for sister chromatid cohesion in meiosis and mitosis.

Sister chromatid cohesion is fundamental for the faithful transmission of chromosomes during both meiosis and mitosis. Proteins involved in this process are highly conserved from yeasts to humans. In screenings for sterile animals with abnormal vulval morphology, mutations in the Caenorhabditis elegans evl-14 and scc-3 genes were isolated. Defects in cell divisions were observed in germ line as well as in vulval and somatic gonad lineages. Through positional cloning of these genes, we have shown that EVL-14 and SCC-3 are likely the only C. elegans homologs of the yeast sister chromatid cohesion proteins Pds5 and Scc3, respectively. Both evl-14 and scc-3 mutants displayed defects in the meiotic germ line. In evl-14 mutants, synaptonemal complexes (SCs) were detectable but more than the usual six DAPI (4',6'-diamidino-2-phenylindole)-positive structures were seen at diakinesis, suggesting that EVL-14/PDS-5 is important for the maintenance of sister chromatid cohesion in late prophase. In scc-3 mutant animals, normal SCs were not visible and approximately 24 DAPI-positive structures were seen at diakinesis, indicating that SCC-3 is necessary for sister chromatid cohesion. Immunostaining revealed that localization of REC-8, a homolog of the yeast meiotic cohesin subunit Rec8, to the chromosomes depends on the presence of SCC-3 but not that of EVL-14/PDS-5. scc-3 RNA interference (RNAi)-treated embryos were 100% lethal and displayed defects in cell divisions. evl-14 RNAi caused a range of phenotypes. These results indicate that EVL-14/PDS-5 and SCC-3 have functions in both mitosis and meiosis.

Animals↗
PubMed2003

Ana o 2, a major cashew (Anacardium occidentale L.) nut allergen of the legumin family.

BACKGROUND: We recently cloned and described a vicilin and showed it to be a major cashew allergen. Additional IgE-reactive cashew peptides of the legumin group and 2S albumin families have also been reported. Here, we attempt to clone, express and characterize a second major cashew allergen. METHODS: A cashew cDNA library was screened with human IgE and rabbit IgG anti-cashew extract antisera, and a reactive nonvicilin clone was sequenced and expressed as a fusion protein in Escherichia coli. Immunoblotting was used to screen for reactivity with patients' sera, and inhibition of immunoblotting was used to identify the corresponding native peptides in cashew nut extract. The identified allergen was subjected to linear epitope mapping using SPOTs solid-phase synthetic peptide technology. RESULTS: Sequence analysis showed the selected clone, designated Ana o 2, to encode for a member of the legumin family (an 11S globulin) of seed storage proteins. By IgE immunoblotting, 13 of 21 sera (62%) from cashew-allergic patients were reactive. Immunoblot inhibition data showed that the native Ana o 2 constitutes a major band at approximately 33 kD and a minor band at approximately 53 kD. Probing of overlapping synthetic peptides with pooled human cashew-allergic sera identified 22 reactive peptides, 7 of which gave strong signals. Several Ana o 2 epitopes were shown to overlap those of the peanut legumin group allergen, Ara h 3, in position but with little sequence similarity. Greater positional overlap and identity was observed between Ana o 2 and soybean glycinin epitopes. CONCLUSIONS: We conclude that this legumin-like protein is a major allergen in cashew nut.

Adult↗
PubMed2003

Influences of a light-dark profile and the pineal gland on the hypnotic activity of melatonin in mice and rats.

We have investigated the influences of the light-dark cycle and the pineal gland on the hypnotic activity of melatonin in rats and mice. The results showed that melatonin significantly shortened time to sleep onset and wakefulness time, increased slow wave sleep, paradoxical sleep, and total sleep time in rats during the light phase of a 12-h light:12-h dark cycle, by electroencephalogram recording. However, during the dark phase it had almost no significant sleep-promoting effect except shortened time to sleep onset. Melatonin exhibited more potent sleep-promoting effect in rats exposed to constant light compared with rats exposed to 12:12-h light:dark at 2000 h. Melatonin markedly prolonged sleeping time in the mice exposed to constant illumination. It was found that pinealectomy was an important factor that influenced the hypnotic activity of melatonin. When melatonin was administered to pinealectomized mice, the hypnotic activity of melatonin was more intense compared with sham-operated mice. These results demonstrated that the hypnotic activity of melatonin displayed a light-dependence manner. These results suggested that light exposure and the functional state of the pineal gland could substantially impact the hypnotic activity of melatonin at pharmacological dosage.

Administration, Oral↗
PubMed2003

Taxol inhibits melanoma metastases through apoptosis induction, angiogenesis inhibition, and restoration of E-cadherin and nm23 expression.

An in vivo melanoma spontaneous metastases model was adopted to study the molecular mechanisms of the anti-metastatic effect of Taxol. The morphology of melanoma cells in the melanoma tissue lesions was examined by hematoxylin/eosin (H&E) staining and electron microscopy. The in situ programmed cell death was tested by TUNEL analysis. Vascular endothelial growth factor (VEGF) and E-cadherin expression were detected by immunohistochemistry. The metastases suppressor gene nm23 mRNA expression level was analyzed by in situ hybridization. The results showed that i.p. injection of Taxol at 5 mg/kg per day for three weeks significantly inhibited metastases formation in the pulmonary of mice. Taxol induced melanogenesis and apoptosis in the melanoma cells, inhibited angiogenesis in melanoma tissue lesions, and reduced the expression of VEGF. Conversely, Taxol increased the expression of E-cadherin and nm23. In conclusion, administration of Taxol in the early stage of melanoma metastases can significantly inhibit melanoma metastases. This effect was possibly related to apoptosis induction, tumor angiogenesis inhibition, and restoration of the metastasis suppression ability.

Angiogenesis Inhibitors↗
PubMed2003

Effects of tetrandrine on calcium and potassium currents in isolated rat hepatocytes.

AIM: To study the effects of tetrandrine (Tet) on calcium release-activated calcium current (I(CRAC)), delayed rectifier potassium current (I(K)), and inward rectifier potassium currents (I(K1)) in isolated rat hepatocytes. METHODS: Hepatocytes of rat were isolated by using perfusion method. Whole cell patch-clamp techniques were used in our experiment. RESULTS: The peak amplitude of I(CRAC) was -508+/-115 pA (n=15), its reversal potential of I(CRAC) was about 0 mV. At the potential of -100 mV, Tet inhibited the peak amplitude of I(CRAC) from -521+/-95 pA to -338+/-85 pA (P<0.01 vs control, n=5), with the inhibitory rate of 35 % at 10 micromol/L and from -504+/-87 pA to -247+/-82 pA (P<0.01 vs control, n=5), with the inhibitory rate of 49 % at 100 micromol/L, without affecting its reversal potential. The amplitude of I(CRAC) was dependent on extracellular Ca(2+) concentration. The peak amplitude of I(CRAC) was -205+/-105 pA (n=3) in tyrode's solution with Ca(2+) 1.8 mmol/L (P<0.01 vs the peak amplitude of I(CRAC) in external solution with Ca(2+) 10 mmol/L). Tet at the concentration of 10 and 100 micromol/L did not markedly change the peak amplitude of delayed rectifier potassium current and inward rectifier potassium current (P>0.05 vs control). CONCLUSION: Tet protects hepatocytes by inhibiting I(CRAC), which is not related to I(K) and I(K1).

Alkaloids↗
PubMed2003

Effects of palmatine on potassium and calcium currents in isolated rat hepatocytes.

AIM: To study the effects of palmatine, a known inhibitor on delayed rectifier potassium current and L-type calcium current (I(Ca,L)) in guinea pig ventricular myocytes, on the potassium and calcium currents in isolated rat hepatocytes. METHODS: Tight-seal whole-cell patch-clamp techniques were performed to investigate the effects of palmatine on the delayed outward potassium currents (I(K)), inward rectifier potassium current (I(K1)) and Ca(2+) release-activated Ca(2+) current (I(CRAC)) in enzymatically isolated rat hepatocytes. RESULTS: Palmatine 0.3-100 microM reduced I(K) in a concentration-dependent manner with EC(50) of 41.62+/-10.11 microM and n(H), 0.48+/-0.07 (n=8). The effect of the drug was poorly reversible after washout. When the bath solution was changed to tetraethylammonium (TEA) 8 mM, IK was inhibited. Palmatine 10 microM and 100 microM shifted the I-V curves of I(K) downward, and the block of I(K) was voltage-independent. Palmatine 0.3-100 microM also inhibited I(CRAC) in a concentration-dependent manner. The fitting parameters were as follows: EC(50)=51.19+/-15.18 microM, and n(H)=0.46+/-0.07 (n=8). The peak value of I(CRAC) in the I-V relationship was decreased by palmatine 10 microM and 100 microM. But the reverse potential of I(CRAC) occurred at Voltage=0 mV in all cells. Palmatine 0.3-100 microM failed to have any significant effect on either inward or outward components of I(K1) at any membrane potential examined. CONCLUSION: The inhibitory effects on I(K) and I(CRAC) could be one of the mechanisms that palmatine exerts protective effect on hepatocytes.

Animals↗
PubMed2003

Action of progesterone on contractile activity of isolated gastric strips in rats.

AIM: To study the effect of progesterone on contractile activity of isolated gastric strips in rats. METHODS: Wistar rats were sacrificed to remove whole stomach. Then, the stomach was opened and the mucosal layer was removed. Parallel to either the circular or the longitudinal fibers, muscle strips were cut from fundus, body, antrum and pylorus. Each muscle strip was suspended in a tissue chamber containing 5 mL Krebs solution. Then the motility of gastric strips in tissue chambers was simultaneously recorded. The preparations were subjected to 1 g load tension and washed with 5 ml Krebs solution every 20 min. After 1 h equilibration, progesterone or antagonists were added in the tissue chamber separately. The antagonists were added 3 min before using progesterone (50 micromol/L(-1)). RESULTS: Progesterone decreased the resting tension of fundus and body longitudinal muscle (LM) (P<0.05). It inhibited the mean contractile amplitude of body and antrum LM and circular muscle (CM), and the motility index of pyloric CM (P<0.05). The inhibition of progesterone on the mean contractile amplitude could be partially blocked by phentolamine in LM of the stomach body (the mean contractile amplitude of body LM decreased from -7.5+/-5.5 to -5.2+/-4.5 P<0.01), and by phentolamine or indomethacin in CM of body (The inhibition of progesterone on the mean contractile amplitude of body CM decreased from -5.6+/-3.0 to -3.6+/-2.7 by phentolamine and from -5.6+/-3.0 to -3.5+/-2.5 by indomethacin, P<0.01). Hexamethonium, propranolol and L-NNA (inhibitor of NO synthetase) didn't affect the action of progesterone (P>0.05). CONCLUSION: The study suggested that progesterone can inhibit the contractile activity of isolated gastric strips in rats and the mechanism seems to be a direct one except that the action on gastric body is mediated through prostaglandin and adrenergic alpha receptor partly.

Animals↗
PubMed2003

Clinical study on nutrition support in patients with severe acute pancreatitis.

AIM: To investigate the effect of nutritional support therapy on severe acute pancreatitis (SAP). METHODS: A total of 96 patients with severe acute pancreatitis were divided randomly into control and treatment groups. The former group received total parenteral nutrition (TPN) via central venous infusion, while parenteral nutrition (PN) and enteral nutrition (EN) therapies were applied in different phases for the latter group. The nutrition status, acute phase responses, pancreas lesions, enteric mucosa penetrability and immune functions were monitored. RESULTS: Body weight and prealbumin concentration were increased in treatment group, compared to those in the control group, but albumin concentration did not change significantly. Acute physiology and chronic health evaluation II (APACHE II) scores decreased after 7 d of treatment, whereas the scores of the control group decreased on the 11(th) day. Concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukine-6 (IL-6) and serum C reactive protein (CRP) dropped earlier in the treatment group (on the 4(th) day) than that in the control group (on the 7(th) day). No difference was observed in pancreatic lesions between the control and treatment groups. Concentration of endotoxin and lactulose/manicol (L:M) ratio of urine did not change in treatment group, but those in the control group were elevated markedly. Compared with the treatment group, CD4:CD8 T cells ratio and immunoglobulin G (IgG) concentration in the control group decreased significantly. CONCLUSION: Compared to TPN, the combined therapy of EN and PN could improve the nutrition status and moderate the acute phase response obviously. Moreover, the integrity of enteric mucosa and immune function were protected more effectively in treatment group than in the control one. On the other hand, EN did not simulate the excretion of pancreas and avoid exaggerating the inflammation of pancreas. Thus, appropriate application of PN and EN appears to be more effective for patients with SAP.

Acute Disease↗
PubMed2003

[Application of molecular biological techniques in the surveillance of influenza viruses in infants and young children].

OBJECTIVE: To establish a rapid, specific and effective technique for identifying subtyping A(1), A(3) and B of influenza virus isolates and clinical specimens as well as to analyze the sequences of nucleotides and deduced amino acids of HA1 regions from isolates of influenza virus A(3) isolated from 1996 to 2002. METHODS: Six inner and outer sets of oligonucleotide primers were designed to detect, type and subtype human influenza A and B. The first two corresponding sets differentiate type A and B of matrix (M) gene while, the second two corresponding sets identify the H(1) and H(3) subtypes of type A virus HA gene. To type and subtype influenza viruses in clinical isolates, a mixture of inner primer sets specific for H(1), H(3) and B were used in a single PCR reaction tube. To detect influenza viruses in clinical specimens, a mixture of the outer primer sets were used in a single primary PCR tube, and the inner ones in a single second PCR reaction tube. Amplified products were visualized in 1.2% agrose gel containing ethidium bromide. HA1 regions of hemagglutinin of 5 field strains (H3N2) isolated from 1996 to 2002 in Beijing were amplified by RT-PCR and sequenced directly. RESULTS: There was 100% correlation between multiplex RT-PCR and culture to type and subtype influenza viruses from clinical isolates. For typing and subtyping, 76.9%, 57.1% and 86.5% were positive for A(1), A(3) and B by multiplex nested-PCR compared within virus isolation on culture, respectively. The sequence data of HA1 of A(3) strains showed that there was a high homology of nucleotide and amino acid, and the closer the date of isolating was, the higher homology showed. CONCLUSIONS: Multiplex RT-PCR and nested-PCR for influenza viruses could provide a useful alternative to existing methods of influenza detected and identified from clinical isolate and specimens. There were certain, continuous mutations and increasing glycosylated sites which might cause the antigen drift in the A(3) strains during 1996-2002 in Beijing area.

Amino Acid Sequence↗
PubMed2003

[Vesicular stomatitis virus G-protein retrovector mediated a herpes simplex virus thymidine kinase gene transduction and expression in the human retinal pigment epithelial cells].

OBJECTIVE: The herpes simplex virus-thymidine kinase suicide gene (HSV-TK) was delivered to the human retinal pigment epithelial cell (RPE) by a new vesicular stomatitis virus G protein (VSV-G) retroviral vector. The growth inhibitory effects of ganciclovir on VSV-G/HSV-TK transfected RPE were studied. METHODS: A VSV-G retrovirus-packaging cell line 293GPG was transferred with retroviral vector plasmas bearing HSV-TK (G1NaCTK) or galactosidase (LacZ gene, G1BgSvNa) to produce a 293GPG/TK cell line or a 293GPG/LacZ cell line, respectively. LacZ activity was assessed following transduction of CRL2302 cells. HSV-TK transfected RPE and NIH3T3 cells (at different titer levels) were treated with ganciclovir. The growth inhibitory effects of ganciclovir on various cell lines were studied. RESULTS: The titer of VSV-G/HSV-TK concentration was 1.2 x 10(8) cfu/ml. At a high titer (MOI = 200), the efficiency of LacZ gene transfer in CRL2302 cells was 58%. Ganciclovir inhibited the growth of cells transfected by HSV-TK. The maximum inhibitory rate (45%) was obtained at cells with a high titer (MOI = 200). CONCLUSION: Our results suggested that VSV-G/LacZ and VSV-G/HSV-TK retroviral vectors are highly efficient for in vitro delivery and stable expression of genes in NIH3T3 cells and human RPE cells. The cells modified by HSV-TK gene are very sensitive to ganciclovir and the cell growth can be inhibited by ganciclovir.

Cells, Cultured↗
PubMed2003

[Polymorphism of c-Ha-ras 3'VNTR in hydatidiform mole and its relationship with the development of postmolar tumor].

OBJECTIVE: To study the polymorphism of c-Ha-ras 3' variable number of tandem repeat (VNTR) and its relationship with development of postmolar tumor. METHODS: The cases of hydatidiform mole (HM) were retrospectively analyzed by amplified fragment length polymorphism-polyacrylamide gel electrophoresis. The DNA origin of HM was determined by comparison with the parents' DNA amplified results. RESULTS: Among the samples from 15 cases, DNA from only paternal origin was found in 2 cases. DNA from both parents was in 13 cases, and of these 13 cases, 2 were found to be had balanced DNA origin, 11 had more DNA form paternal origin than DNA from maternal origin. CONCLUSION: The HM which has DNA from both parents origin and predominantly from paternal origin developed to postmolar tumor more frequently.

3' Flanking Region↗
PubMed2003

Perforated patch recording of L-type calcium current with beta-escin in guinea pig ventricular myocytes.

AIM: To establish a perforated patch recording (PPR) mode with beta-escin and compare L-type calcium current (I(Ca,L)) recorded under PPR and normal whole-cell recording (WCR) condition in isolated guinea-pig ventricular myocytes. METHODS: Single myocytes were dissociated by enzymatic dissociation method. beta-escin was added to the pipette solution to perforate the cell membrane and obtain PPR mode. I(Ca,L) was recorded using PPR and WCR techniques. RESULTS: beta-Escin 20, 25, and 30 micromol/L could permeabilize the cell membrane and obtain PPR mode. With beta-escin 25 micromol/L, the success rate was highest (16/17, 94 %) and the time required for permibilization was 2-15 (8+/-4) min. Run-down of I(Ca,L) was considerably slower in PPR than in WCR condition. The amplitude of I(Ca,L) was decreased by 36 % at 20 min after the formation of WCR, while it was slowly decreased by 8 % at 30 min after the formation of PPR. The current-voltage relation (I-V) curves, activation and inactivation curves of I(Ca,L) were not significantly different between WCR and PPR. The inactivation rate of ICa,L was slower in PPR than in WCR, the faster inactivation time constant (tau(f)) was longer in PPR than in WCR at membrane potentials of -20 mV -- +10 mV (n=6, P<0.05), and the slower time constant (tau(s)) was also longer in PPR than in WCR at membrane potentials of -10 mV to +10 mV (n=6, P<0.05). There was no significant difference between the activation rate in WCR and PPR. CONCLUSION: Using beta-escin 25 micromol/L can easily obtain stable PPR in isolated guinea-pig ventricular myocytes, and this method is useful in dealing with channels, which show run-down under normal WCR such as L-type Ca channel.

Animals↗
PubMed2003

[Research advances on function of promyelocytic leukemia (PML) protein].

Through reviewing research advances on promyelocytic leukemia(PML) protein at home and abroad in recent years, the authors summarized the biological functions of PML protein in this paper. Recent researches indicated that all PML protein isoforms have RBCC (Ring finger domain, B-box, Coiled-Coil domain, RBCC)or TRIM (TRIpartite motif). There was a close relationship between the three SUMO-1 (small ubiquitin-related modifier, SUMO-1) modification site of PML protein and its location in nuclear bodies (NBs). Moreover, the location of PML protein in NBs is very important for the exertion of the function of PML protein and the formation of NBs. PML protein possesses multiple biological functions, such as intrinsic antiviral activities, suppressing the growth of tumor, participating in the differentiation of hemopoietic progenitor, regulating transcription of genes, inducing cell apoptosis, and so on. The PML gene haploinsufficiency and the formation of PML-RARalpha fusion protein are not only the pathogenesis of APL but also the target of treatment.

Animals↗