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At least 379 records · Page 21Linked to original sources

PubMed2004

[Study on the antioxidative effect of Safflor Yellow].

OBJECTIVE: To observe the antioxidative effect of Safflor Yellow (SY). METHOD: Hydroxyl radical scavenge effect of SY was tested with 1,10-phenanthroline-Fe2+ oxidative assay. Lipid peroxidation of mouse liver suspension was measured with thiobarbituric acid colorimetry technique. Hemocytocatheresis was determined with colorimetry. RESULT: Hydroxyl radical could be scavenged by 1.39 to 3.42 g x L(-1) SY dose dependently. Mouse liver suspension peroxidation was inhibited by 77.8 to 776.1 mg x L(-1) SY dosage dependently. Hemocytocatheresis was attenuated by 37.1 to 297.1 mg x L(-1) SY dose dependently. CONCLUSION: SY is an antioxidative part of Carthamus tinctorius.

Animals↗

PubMed2005

Effects of Smac gene over-expression on the radiotherapeutic sensitivities of cervical cancer cell line HeLa.

BACKGROUND: The second mitochondria-derived activator of caspases (Smac) is a novel proapoptotic gene, which plays an important role in the apoptosis-inducing effects of irradiation on tumor cells. The purpose of this study was to investigate the effects of extrinsic Smac gene transfer and its over-expression in radiotherapeutic sensitivities of cervical cancer cells. METHODS: After the Smac gene was transferred into the cervical cancer cell line HeLa, subcloned cells were obtained by persistent G418 selection. Cellular Smac gene expression was detected by RT-PCR and Western blot, while in vitro cell viabilities were detected by trypan blue staining assay. After treatment with X-ray irradiation, cellular radiotherapeutic sensitivities were investigated by tetrazolium bromide colorimetry. Cellular apoptosis and its rate were determined by electronic microscopy, annexin V-FITC and propidium iodide staining flow cytometry. The expression and activities of cellular caspase-3 were assayed by Western blot and colorimetry. RESULTS: Smac mRNA and protein levels in HeLa/Smac cells and the selected subclone cell line of cervical cancer were significantly higher than those of HeLa (P < 0.01). There was no significant difference in cellular viabilities between them (P > 0.05). However, after irradiation with 8 Gy X-ray, growth activities of HeLa/Smac were reduced by 22.42% (P < 0.01). When compared with those of HeLa, partial HeLa/Smac cells presented characteristic morphological changes of apoptosis under electronic microscope, with higher apoptosis rates (16.4% vs. 6.2%, P < 0.01); the caspase-3 expression levels in HeLa/Smac cells were improved significantly (P < 0.01), while its activities were increased by 3.42 times (P < 0.01). CONCLUSIONS: Stable transfer of the extrinsic Smac gene and its over-expression in cervical cancer cell line could significantly enhance the expression and activities of cellular caspase-3 and ameliorate apoptosis-inducing effects of irradiation on cancer cells, which was a novel strategy to improve radiotherapeutic effects on cervical cancer.

Apoptosis↗

PubMed2005

[An experimental study of the effect of IL-2 on the growth of irradiated intestinal epithelial cells].

AIM: To observe the effect of ionizing radiation on intestinal epithelial cells 6 (IEC-6) and the effect of IL-2 on the proliferation and recovery of radiation-injured IEC-6 cells. METHODS: IEC-6 cells exposed to 4, 8 and 12 Gy gamma ray were analyzed with MTT colorimetry, light microscopy, electron microscopy, DNA gel electrophoresis and flow cytometry at 3, 6, 9, 12 hours and 1, 2, 3 days after radiation. Proliferation of 8 Gy gamma ray-irradiated IEC-6 cells which was treated with IL-2 was detected by MTT colorimetry at 3, 6, 9, 12 and 24 hours after irradiation. RESULTS: Proliferation of IEC-6 decreased with the increased dose of gamma ray radiation. Apoptotic IEC-6 cells increased apparently at 24 hours after radiation with 8.0 Gy gamma ray, IL-2 could enhance the proliferation of irradiated IEC-6 cells (especially at concentration of 1 x 10(5) U/L) in a dose-dependent manner. CONCLUSION: 4-12 Gy of gamma ray radiation can reduce the proliferation and cause apoptosis of IEC-6 cells. IL-2 can accelerate proliferation of irradiated IEC-6 cells and protect IECs from ionization radiation injury.

Animals↗

PubMed2005

[Preliminary study on anti-tumor function of resveratrol and its immunological mechanism].

AIM: To explore the immunological mechanism of the anti-tumor function of resveratrol (Res) through in vitro or vivo experiments. METHODS: The tumor cell growth repression rate was measured by MTT colorimetry. Flow cytometry was used to analyze the cell cycle of Hep2 cells (laryngeal squamous cancer cell line). The immune function and cytokine levels in the serum of the tumor-bearing mice were determined by MTT colorimetry, hemolysis spectrophotography, improved Mayer's method and ELISA. RESULTS: Res inhibited the tumor cell growth and enhanced the apoptosis of tumor cells in time-concentration-dependent manners showing the phenomenon of obvious G(0)/G(1) blocking and apoptotic peak. The maximal tumor inhibition rate came up to 42.76%. Furthermore, Res improved function of T, B lymphocytes, killing activity of NK cells, release of antibodies, and the total complement activity in serum. It also increased contents of IL-2 and TGF-beta1 but reduced that of IL-8 and VEGF. CONCLUSION: Res can not only affect tumor cells directly but also exert anti-tumor efficiency through reinforcing cell-mediated, humoral immune response and accommodating lymphocytes to secrete cytokines.

Animals↗

PubMed2005

[Study on effects of salidroside on lipid peroxidation on oxidative stress in rat hepatic stellate cells].

OBJECTIVE: To investigate the effect of antioxidant Salidroside on the lipid peroxidation of oxidative stress in rat hepatic stellate cells in vitro. METHODS: HSC-T6 were incubated with 0.1 mM ferric nitrilotriacetate complex (FeNTA). MTT colorimetry was used for assaying proliferation of HSC. Cytotoxicity was measured by LDH colorimetry. Collagen type I accummulation in the culture media was measured by ELISA. Intracellular MDA, SOD, GSH and GSH-PX levels in the culture media were measured by their reagent boxes. RESULTS: HSC incubation with FeNTA resulted in a significant production of intracellular MDA and GSH, associated with decreasing SOD and GSH-PX activity. Exposure of HSC to FeNTA significantly enhanced the number of proliferating HSC and collagen type I levels in the culture medium. All these effects were reversed by the antioxidant Salidroside. CONCLUSION: The mechanism of Salidroside on fibrosis may be related to inhibit lipid peroxidation.

Animals↗

PubMed2006

[Comparison on growth, physiology and medicinal components of Dendrobium huoshanense hybrid and its parents].

OBJECTIVE: To compare the hybrid between species of Dendrobium huoshanense and its parents on growing, physiologic indexes and content of medicinal components, and provide theoretical basis for species quality improvement. METHOD: The chlorophyll content, the photosynthesis rate, the polysaccharides content and the alkaloids content were measured by anhydrous ethanol method, Cl-310 photosynthesis determination system, colorimetry of concentrated sulphuric acid-phenol and acid dyes colorimetry respectively. RESULT: The growth of hybrid was close to D. moniliforme, and apparently higher than D. huoshanense. The chlorophyll content and the photosynthesis rate of one-year-hybrid were markedly higher than its parents. The content of polysaccharides and alkaloids in two-year-stem and three-year-stem of hybrid were close to that of D. huoshanense. CONCLUSION: The hybrid integrates superiority of parents on growth and accumulation of medicinal components opens vast vistas for development and utilization.

Alkaloids↗

PubMed1991

Amocarzine investigated as oral onchocercacidal drug in 272 adult male patients from Guatemala. Results from three dose regimens spread over three days.

The clinical investigations with three types of a three days regimen of amocarzine permitted to adjust the fixed dosing to the body weight related dosing and subsequently the administration of amocarzine from fasting state to drug intake after food. The main objective to reach a dose with predictable and sustained absorption was achieved, and this in turn proved to be onchocercacidal and safe. A combined clinicopharmacokinetic study showed enhancement and consistency of amocarzine absorption after food. Quantitative assessment of the urinary excretion confirmed the presence of the N-oxide metabolite, which qualitatively was visible by a urine colorimetry. This assay proved useful for drug monitoring. Ultrasonography of onchocercal skin nodules detected changes within the nodules following amocarzine therapy. Histology after nodul-ectomy at four months post-therapy showed that 57% of the female worms were dead, 24% necrobiotic, and 19% alive; male worms were more necrobiotic. Skin microfilariae were reduced within one week to about 10% of the initial level and after one year they remained at about 20%. Skin punch biopsies on day 5 showed that most microfilariae were dead or moribund. Ocular reduction of microfilariae was also observed, although it was slower than in the skin. The visual acuity improved within the one year's observation time. Ocular and clinical tolerability was good, with one exception of neurological disturbance, which was fully reversible. Sequential testing of the liver function showed average values within the normal range. In conclusion, a repeat low dose regimen of amocarzine (3 mg/kg twice daily post-prandially for three consecutive days) was well absorbed with predictable plasma levels, macro- and microfilaricidal with good local and systemic tolerability in patients with moderate to heavy onchocerciasis. Amorcarzine is recommended for further clinical investigations, particularly in females and juveniles. Urine colorimetry and nodular ultrasonography are recommended for optional monitoring of amocarzine.

Administration, Oral↗

PubMed1994

[Inhibitory effect of taohong siwu decoction on collagen crosslinking, hyaluronic acid cleavaging and lipid peroxidation].

It has been demonstrated by cytochrome C colorimetry that the Taohong Siwu Decoction (TF) is effective in hydroxyl radical scavenging. TBA colorimetry has proved that TF is effective in inhibiting lipid peroxidation. As detected by viscometry hyaluronic acid cleavage induced by hydroxyl radical can be inhibited by TF. It has been demonstrated by SDS-PAGE method that TF is effective in inhibiting collagen crosslinking.

Animals↗

PubMed1996

Cutaneous microdialysis. Methodology and validation.

This thesis describes the methodology and validation of cutaneous microdialysis for the study of skin penetration of various topically applied substances in experimental dermatological research. Microdialysis is a sampling technique which makes it possible to measure substances in the extracellular water space in human and animal skin in vivo. A microdialysis probe, i.e. a tubular semipermeable membrane connected to afferent and efferent tubings, is placed in the dermis and perfused. Substances from extracellular space may diffuse through the pores of the membrane and be collected in the dialysate for further analysis. Glucose, sodium fusidate, betamethasone 17,21-dipropionate and calcipotriol were chosen as model substances and were investigated by in vitro microdialysis. The perfusion rate, the length of the membrane, stirring rate and temperature influenced recovery of the substances. Lipophilic compounds tend to have low recoveries and differ in recovery and loss. Insertion of the microdialysis probe causes a trauma in the skin. Rat and human skin were studied in vivo. Increase in skin blood flow, erythema and skin thickness were demonstrated by laser Doppler perfusion imaging, Dermaspectrometer colorimetry, Minolta Chromameter colorimetry and ultrasound imaging of cross-sectional skin structure. In addition histamine was released in rat skin due to the needle insertion. An equilibration period of minimum 90 min in human skin and 30 min in rat skin after the insertion is necessary to allow the effects of trauma to diminish. To obtain measurable concentrations in the dialysate in rats treated topically with the lipophilic drug betamethasone 17-valerate, unrealistic high doses and penetration enhancement were required. The highly protein-bound drug fusidic acid was not measurable in the dialysate after topical application, probably due to very low concentrations of free diffusible drug. Measurable concentrations were only observed after high doses of oral administrations of fusidic acid. Calcipotriol could not be detected in the dialysate. The microdialysis technique is probably primarily useful for the study of hydrophilic substances and substances with low protein binding and low molecular weight. However, application of cutaneous microdialysis for the study of lipophilic substances need further methodologically development.

Animals↗

PubMedDate not supplied

Chemical and physical analysis for the improvement of the dry mounting method for fragile documents.

Paper lamination is a widely used method to consolidate fragile documents. Previous studies have presented a new method of lamination that allows the consolidation of documents before undertaking aqueous treatments. In this method a thin Japanese paper coated with an acrylic resin is applied on the fragile document by means of a heated press. In this work we optimised the preparation of the lamination sheets as well as the working procedures, and we were able to establish that our laboratory-made specimens are chemically stable, easily reversible and permeable to aqueous solutions. The latest property is of particular importance, since it allows a subsequent aqueous deacidification even for fragile documents. The laminated paper documents were further analysed by means of colorimetry and FTIR spectroscopy before and after accelerated ageing as well as by determination of the alkali reserve left on the coated paper, in order to compare our lamination method with other commercially available lamination sheets.

Acrylic Resins↗

PubMedDate not supplied

A rapid and sensitive 384-well microtitre format chemiluminescent enzyme immunoassay for 19-nortestosterone.

We developed a competitive chemiluminescent (CL) enzyme immunoassay for rapid, sensitive analysis of 19-nortestosterone (19-NT) in bovine urine. Anti-19-NT polyclonal antibodies were raised in rabbits using a 19-NT-hemisuccinate derivative conjugated with ovalbumin; the derivative was also conjugated with horseradish peroxidase (HRP) as a label. Antibodies were immobilized on 384-well black polystyrene microtitre plates and HRP-labelled 19-NT activity was measured using an efficient chemiluminescent substrate (SuperSignal ELISA Femto) after 3 min incubation. Emitted light was recorded using a conventional, photomultiplier-tube-based microtitre plate reader or a sensitive back-illuminated, cooled CCD camera. The developed method fulfils all the requirements of precision (intra- and inter-assay CV < 10%) and accuracy (mean recovery 94-112%), with a detection limit of 0.03 ppb (1.1 x 10(-9) mol/L) in a urine matrix. Chemiluminescence enhances detectability of the HRP-labelled tracer (thus lowering the limit of detection with respect to colorimetry) and reduces analysis time. The 384-well microtitre plate cuts the sample/reagent volume (20 microL), a five-fold reduction with respect to the conventional 96-well microtitre plate. The developed method is suitable for high-throughput screening of 19-NT in urine samples, with reduced costs as compared with conventional colorimetric enzyme immunoassays.

Anabolic Agents↗

PubMed2004

Atheromatous plaque cap thickness can be determined by quantitative color analysis during angioscopy: implications for identifying the vulnerable plaque.

BACKGROUND: Coronary angioscopy in acute myocardial infarction has frequently revealed disrupted yellow lesions. Furthermore, postmortem studies have demonstrated that these lesions have thin collagenous caps with underlying lipid-rich cores. HYPOTHESIS: We hypothesized that the yellow color is due to visualization of reflected light from the lipid-rich yellow core through a thin fibrous cap. Thus, quantification of yellow color saturation may estimate plaque cap thickness and identify vulnerable plaques. METHODS: To test this hypothesis, the feasibility of detecting cap thickness was tested using both a model of lipid-rich plaque and human atherosclerotic plaque. The model was constructed by injecting a yellow beta-carotene-lipid emulsion subendothelially into normal bovine aorta. Human plaque was obtained from cadaver aorta. Digitized images were obtained by angioscopy, and percent yellow saturation was analyzed using a custom computer program. Plaque cap thickness was measured by planimetry of digitized images on stained tissue sections. Percent yellow saturation was then correlated with plaque cap thickness. RESULTS: In the bovine model, plaque cap thickness and percent yellow saturation correlated inversely (r2 = 0.91; p = 0.0001). In human plaques, yellow saturation was significantly greater in atheromatous than in white plaques (p < 0.0004). Also, there was a high correlation between plaque cap thickness and yellow saturation at various angles of view between 40 degrees and 90 degrees, the greatest between 50 degrees and 80 degrees (r2 = 0.75 to 0.88). CONCLUSION: Plaque cap thickness is a determinant of plaque color, and this can be assessed by quantitative colorimetry. Thus, plaque color by angioscopy may be useful for detecting vulnerable plaques.

Angioscopy↗

PubMed2001

An improved assay for the N-acetyl-D-glucosamine reducing ends of polysaccharides in the presence of proteins.

Hyaluronan concentration and hyaluronidase activity can be assayed by using different techniques including turbidimetry, viscosimetry, ELISA, chromatography, and colorimetry. The most popular colorimetric method is that of J. Reissig et al. (1955, J. Biol. Chem. 217, 959-966), in which the color results from a reaction between the Ehrlich's reagent (DMAB) and the N-acetyl-d-glucosamine reducing end of each hyaluronan chain. Nevertheless, there are problems with this method when proteins are present in the medium. Here we propose a new interpretation of the Reissig signal for estimating such reducing ends in media containing enzymes or other proteins. This interpretation is based on the fact that the absorbance obtained by using the Reissig method results from two factors: a turbidity due to the formation of polysaccharide-protein complexes and a color resulting from the action of DMAB on the reducing end of the polysaccharide chains. The turbidity at 585 nm, the wavelength at which the color intensity is maximal, may be estimated by curve fitting the spectrum between 450 and 650 nm. Subtracting the turbidity from the absorbance gives the colorimetric intensity which represents the concentration of polysaccharide chains. Moreover, the turbidity may give additional information about the existence of polysaccharide-protein complexes and their nature.

Acetylglucosamine↗

PubMed1995

Acute exposure to realistic acid fog: effects on respiratory function and airway responsiveness in asthmatics.

Naturally occurring fogs in industrialized cities are contaminated by acidic air pollutants. In Brussels, Belgium, the pH of polluted fogwater may be as low as 3 with osmolarity as low as 30 mOsm. In order to explore short-term respiratory effects of a realistic acid-polluted fog, we collected samples of acid fog in Brussels, Belgium, which is a densely populated and industrialized city, we defined characteristics of this fog and exposed asthmatic volunteers at rest through a face mask to fogs with physical and chemical characteristics similar to those of natural fogs assessed in this urban area. Fogwater was sampled using a screen collector where droplets are collected by inertial impaction and chemical content of fogwater was assessed by measurement of conductivity, pH, visible colorimetry, high pressure liquid chromatography, and atomic absorption spectrophotometry over a period of one year. The fogwater composition was dominated by NH4+ and SO4- ions. First we evaluated the possible effect of fog acidity alone. For this purpose 14 subjects with asthma were exposed at rest for 1 hr [mass median aerodynamic diameter to a large-particle (MMAD), 9 microns] aerosol with H2SO4 concentration of 500 micrograms/m3 (pH 2.5) and osmolarity of 300 mOsm. We did not observe significant change in pulmonary function or bronchial responsiveness to metacholine. In the second part of the work, 10 asthmatic subjects were exposed to acid fog (MMAD, 7 microns) containing sulfate and ammonium ions (major ions recovered in naturally occurring fogs) with pH 3.5 and osmolarity 30 mOsm. Again, pulmonary function and bronchial reactivity were not modified after inhalation of this fog. It was concluded that short-term exposure to acid fog reproducing acidity and hypoosmolarity of natural polluted fogs does not induce bronchoconstriction and does not change bronchial responsiveness in asthmatics.

Acid Rain↗

PubMed1994

Chemiluminescent and colorimetric detection of a fluorescein-labelled probe and a digoxigenin-labelled probe after a single hybridization step.

The objective of the simple and fast method we describe is the simultaneous hybridization of two non-radioactive probes and their detection from the same blot, using two different systems. These two probes are synthesized by PCR: one is labelled with fluorescein and the other with digoxigenin. The former is detected by chemiluminescence and the latter by colorimetry. We applied this rapid and simple method to the specific detection of multiplex polymerase chain reaction products. We used the human herpes simplex virus HSV1 and HSV2 PCR models studied in our laboratory.

Base Sequence↗

PubMed2006

Growth inhibition and apoptosis inducing mechanisms of curcumin on human ovarian cancer cell line A2780.

OBJECTIVE: To explore the growth inhibition effects and apoptosis inducing mechanisms of curcumin on human ovarian cancer cell line A2780. METHODS: After treatment with 10 - 50 micromol/L curcumin for 6 - 24 h, the growth activity of A2780 cancer cells were studied by [4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) colorimetry. Cellular apoptosis was inspected by flow cytometery and acridine orange-ethidium bromide fluorescent staining methods. The fragmentation of cellular chromosome DNA was detected by DNA ladder, the ultrastructural change was observed under a transmission electron microscope, and the protein levels of nuclear factor-kappa B (NF-kappaB, P65) and cysteinyl aspartate specific protease-3 (Caspase-3) in ovarian cancer cells were measured by immunohistochemistry. RESULTS: After treatment with various concentrations of curcumin, the growth inhibition rates of cancer cells reached 62.05% - 89.24%, with sub-G(1) peaks appearing on histogram. Part of the cancer cells showed characteristic morphological changes of apoptosis under fluorescence and electron microscopes, and the rate of apoptosis was 21.5% - 33.5%. The protein expression of NF-kappaB was decreased, while that of Caspase-3 was increased in a time-dependent manner. CONCLUSION: Curcumin could significantly inhibit the growth of human ovarian cancer cells; inducing apoptosis through up-regulating Caspase-3 and down-regulating gene expression of NF-kappaB is probably one of its molecular mechanisms.

Acridine Orange↗

PubMed2002

Studies on reactions of ozone with alkenes.

In the last years, a continuous increase of the O3 concentration has been recorded in the lower atmospheric layers. Photochemical reactions with NO(x), CO and organic compounds are the main sources of O3 in the troposphere. In this work, an attempt was made to determine the impact of alkenes on the O3 concentration in the troposphere. A study on the gas-phase reactions of 03 with 1-hexene, 1-heptene and 1-nonene was made. The reactions were carried out at room temperature under atmospheric pressure. Ozone was formed by the ultraviolet radiation emitted by a mercury lamp, in order to simulate the atmospheric conditions. The changes with time in the concentration of O3, 1-alkenes and formed aldehydes were investigated. Qualitative and quantitative analyses were done by means of the gas chromatography and colorimetry. The following products were identified: pentanal from 1-hexene; hexanal from 1-heptene; oktanal from 1-nonene. For each of the reactions, HCHO was also determined as a product. The reaction rate constants were calculated and obtained in units of 10(-17) cm(-3) molecule(-1) s(-1): 1.94-0.99 for 1-hexene, 5.54-4.51 for 1-heptene and 1.54-0.76 for 1-nonene. Based on the results obtained, an explanation of O3 concentration variations in the planetary boundary layer can be given. Last year a considerable increase of O3 concentration on the roads of Western Europe was recorded. This increase could have resulted from the decrease of alkene concentration in the air due to common use of the catalytic converters in cars. The unsaturated hydrocarbons rapidly oxidize on the catalyst. In Eastern Europe, where the amount of cars equipped with catalytic converters is smaller than in Western Europe, the alkene content in the exhaust fumes results in a decrease of the O3 concentration in the troposphere.

Air Pollutants↗

PubMedDate not supplied

Quantitative structure--pharmacokinetic relationship of a series of sulfonamides in the rat.

The pharmacokinetics of a series of sulfonamides were investigated after intravenous administration of a 7 mg/kg dose of individual sulfonamides to cannulated female lean Zucker rats. The concentrations of the sulfonamides in blood were determined by colorimetry. The blood concentration-time curves were fitted to a biexponential equation. The partition coefficient, log P, and pKa values of the sulfonamides were taken from the literature, log P and pKa values differed markedly across the series. The extent of protein binding varied enormously, increasing with partition coefficient. There was no significant relationship between the volume of distribution and partition coefficient. However, when the influence of protein binding on volume of distribution was eliminated, a significant linear relationship emerged. Total clearance formed a relatively complex nonlinear relationship with partition coefficient. The relationship of elimination half-life and partition coefficient was inverse of that between clearance and partition coefficient because of a lack of significant relationship between volume of distribution and partition coefficient.

Animals↗