[Progress in the study of maternal-fetal vertical transmission of human immunodeficiency virus type-1].
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
Xia Wu
Publications and source records attributed to Xia Wu.
Resonance light-scattering method for the determination of BSA and HSA with sodium dodecyl benzene sulfonate or sodium lauryl sulfate.
A new resonance light-scattering (RLS) assay of proteins such as bovine serum albumin (BSA) and human serum albumin (HSA) is presented. In the medium of phosphoric acid (pH=2.6), the weak RLS of sodium dodecyl benzene sulfonate (SDBS) or sodium lauryl sulfate (SLS) can be greatly enhanced by proteins, owing to interaction between the protein and the anionic surfactant and formation of an associate. The RLS intensity of the SDBS-protein system is stronger than that of the SLS-protein system under same experimental conditions. It is considered that the synergistic resonance caused by the absorption of both protein and SDBS could produce strong RLS, while absorption of protein only in the SLS system could cause relatively weak RLS. The enhanced intensity of RLS is proportional to the concentration of the protein. If SDBS is used as the probe the linear range is 7.5 x 10(-9)-1.5 x 10(-5) g mL(-1) for BSA and 1.0 x 10(-8)-1.0 x 10(-5) g mL(-1) for HSA. The detection limits are 1.8 and 2.8 ng mL(-1), respectively. When SLS is used as the probe the linear range is 2.0 x 10(-8)-1.0 x 10(-5) g mL(-1) and 2.5 x 10(-8)-1.0 x 10(-5) g mL(-1) for BSA and HSA, respectively, and the detection limits are 12.8 and 21.6 ng mL(-1), respectively. The biological mimics samples are synthetic concoctions of BSA and HSA with some interferents. In these samples, the concentration of interferents is higher than the concentration normally existing in organisms. The samples were determined satisfactorily.
Animals↗
Theoretical evaluation of moderately focused spherical transducers and multi-focus acoustic lens/transducer systems for ultrasound thermal therapy.
Impractically long treatment times are required for highly focused spherical transducers to destroy large tumours because thermal lesions generated by these transducers are small and a large number of such lesions are required. Moderately focused spherical transducers and multi-focus acoustic lens/transducer systems can generate larger thermal lesions compared to those produced by highly focused spherical transducers, and therefore shorter treatment times can be expected. The decrease in total treatment time by the use of moderately focused spherical transducers and acoustic lens/transducer systems was quantified in this study. A 3D ultrasound thermal model was developed to predict thermal lesion volumes generated by ultrasound transducers. A target model was constructed in order to compare various transducer designs under identical treatment conditions and with identical treatment goals. A design method was developed to determine the thickness of lens elements for production of specified multi-focus fields. Then, a highly focused and a moderately focused spherical transducer, and an acoustic lens/transducer system were compared in terms of total time required to treat a tumour. These transducers had identical apertures and operating frequencies. The radius of curvature of the moderately focused spherical transducer was chosen such that the length of thermal lesions it generated over 10 s single exposures was slightly greater than that of the target. The lens/transducer system was designed to produce a 9 focus field. The simulation results show that for the treatment of a 2 x 2 x 2 cm3 tumour at a depth of 5 cm in the body, the highly focused spherical transducer, the moderately focused spherical transducer and the lens/transducer system required 150, 42 and 30 min, respectively.
Acoustics↗
Study on the resonance light scattering spectrum of berberine-cetyltrimethylammonium bromide system and the determination of nucleic acids at nanogram levels.
The interaction of berberine with nucleic acid in the presence of cetyltrimethylammonium bromide (CTMAB) in aqueous solution has been studied by spectrophotometry and resonance light scattering (RLS) spectroscopy. At pH 7.30, the RLS signals of berberine were greatly enhanced by nucleic acid in the region of 300-600 nm characterized by four peaks at 324.0, 386.5, 416.5 and 465.0 nm. The binding properties were examined by using a Scatchard plot based on the measurement of enhanced RLS data at 416.5 nm. Under optimum conditions, the increase of RLS intensity of this system at 416.5 nm is proportional to the concentration of nucleic acid. The linear range is 7.5 x 10(-9)-7.5 x 10(-5) g ml(-1) for calf thymus DNA, 7.5 x 10(-9)-2.5 x 10(-5) g ml(-1) for herring sperm DNA, and 5.0 x 10(-9)-2.5 x 10(-5) g ml(-1) for yeast RNA. The detection limits (S/N = 3) are 2.1 ng ml(-1) for calf thymus DNA, 6.5 ng ml(-1) for herring sperm DNA and 3.5 ng ml(-1) for yeast RNA, respectively. Three synthetic samples were analyzed satisfactorily.
Animals↗
Study on the molecular recognitions of calix[n]arenes to 2,3-diaminonaphthalene by using fluorometric technique.
The molecular recognition properties of calixarenes to 2,3-diaminonaphthalene (DAN) were investigated. We found that the fluorescence emission of DAN has a blue shift after p-sulfonic sodium calix[4]arece (SSCA) was added to DAN. The proposed mechanism of the molecular recognition between SSCA and DAN indicates that DAN goes into the cavity of SSCA with the help of the hydrogen bonding between the amino group of DAN and sulphonyl group of SSCA. The inclusion ratios and inclusion constants of the host-guest complexes are determined by using the deduced equations.
2-Naphthylamine↗
Interaction of cetylpyridine bromide with nucleic acids and determination of nucleic acids at nanogram levels based on the enhancement of resonance Rayleigh light scattering.
Resonance Rayleigh light scattering (RRLS) spectra of cetylpyridine bromide (CPB)-nucleic acid system and their analytical application have been first studied. The effective factors and optimum conditions of the reaction have been investigated. After CPB and nucleic acid are mixed together, a new absorption peak located at 300 nm appeared, which is due to the formation of new ion associate of CPB-nucleic acid. The new associate can result in two apparent RRLS peaks at 310-400 and 460-480 nm. The RRLS peak of the corrected spectra located at 290-350 nm, which indicate that the RRLS is originated from the absorption of CPB-nucleic acid associate. The peak at 460-480 nm disappears in the corrected RRLS spectra, which indicated that this peak is originated from the strong line emission of the Xe lamp. Under the optimum conditions, the enhanced intensity of RRLS is proportional to the concentration of nucleic acid in the range of 5.0 x 10(-9)-5.0 x 10(-5) g ml(-1) for calf thymus DNA (ctDNA), 1.0 x 10(-8)-4.0 x 10(-5) g ml(-1) for fish sperm DNA (fsDNA) and 1.0 x 10(-8)-5.0 x 10(-5) g ml(-1) for yeast RNA (yRNA). The detection limits (S/N = 3) are 4.3, 8.7 and 7.4 ng ml(-1), respectively. Synthetic samples were determined satisfactorily.
Bromine↗
Resonance double light scattering method for the determination of proteins with morin-CTMAB.
A new determination method of proteins with the limit of determination at nanogram levels is proposed by using a common spectrofluorimeter to detect intensity of resonance double line scattering (RDLS). Proteins including bovine serum albumin (BSA), human serum albumin (HSA) can combine with morin and cetyltrimethylammonium briomide (CTMAB) in the pH range 7.0-8.0 and produce enhanced RDLS signal at lambda(ex)/lambda(em) 305.0/610.0 nm. Optimization conditions for the morin-protein-CTMAB interaction were tested. In the studied system, BSA/CTMAB/morin = 1:2:3. The association constant of morin with BSA is 5.2 x 10(4). Under the optimum conditions, the linear range is 7.5 x 10(-8)-1.0 x 10(-5) g/ml for BSA, 2.5 x 10(-8)-5.0 x 10(-6) g/ml for HSA. The detection limits (S/N = 3) are 66.0 ng/ml for BSA and 23.0 ng/ml for HSA, respectively. Four synthetic samples were analyzed satisfactorily.
Animals↗
Accumulation of platelets in the lung and liver and their degranulation following antigen-challenge in sensitized mice.
1. Mast cells and basophils are believed to trigger allergic reactions and anaphylaxis. They rapidly release histamine (H), a typical mediator of inflammation, in response to antigens. In the mouse, platelets contain much 5-hydroxytryptamine (5HT), an additional inflammatory mediator, while human platelets contain both H and 5HT. Here, we examined the response of platelets in sensitized mice to antigen challenge. 2. Platelets accumulated in the lung and liver almost immediately after intravenous injection of ovalbumin (OVA), in mice sensitized to it, and platelet degranulation occurred during these reactions. 3. These responses of platelets preceded H release from mast cells and/or basophils, occurred at doses of OVA lower than those inducing H release, and contributed to the signs of shock. 4. We reported previously that intravenous injection into mice of LPS (a membrane constituent of gram-negative bacteria) induces a similar platelet response (accumulation of platelets in the lung and liver) and shock. 5. Blood that has passed through the body (other than the digestive tract) passes first to the lungs before being recirculated by the heart, and blood that has passed through the digestive tract passes next to the liver. Thus, our findings suggest that in addition to their role in haemostasis, platelets, tiny anuclear cytoplasts, may be important in both innate and acquired immunity, and that the lung and liver may be the fronts at which platelets wage war on pathogens.
Anaphylaxis↗
[Colorectal exfoliated cell in stool and its nuclear DNA quantitative analysis for diagnosis of colorectal cancer].
BACKGROUND AND OBJECTIVES: Detection of colorectal exfoliated epithelial cells and their nuclear DNA content may provide another non-invasive way of screening and early diagnosis of colorectal cancer. This study was designed to analyze the roles of exfoliated cells in stool and its nuclear DNA content in diagnosis of colorectal cancer. METHODS: 1. One hundred and seventy nine individuals were selected, forty-six of them had pathological confirmation of colorectal carcinoma. The other 133 persons had no colonoscopic evidence of colorectal malignancy and therefore served as control. Exfoliated cells in the stool were isolated by elutriation, and the elutriation means was modified Iyengar's method. All individuals in the study had stool specimens for occult blood test(FOBT). 2. Nuclear DNA content and morphometric quantitative analysis in the exfoliated cells was performed on the 33 patients with colorectal cancer and 30 individuals served as control. The parameters selected in this study were DNA content, nuclear area, nuclear irregular index, and percent of > or = 5C cells. RESULTS: 1 Exfoliative cytology and FOBT: In 35 of 46 cases of colorectal malignancy(76.09%), cytology was positive: 5 cases demonstrated dysplastic cells, 4 cases indicated suspected carcinoma cells, 26 cases showed carcinoma cells. The positive rate of exfoliated cells had no significant relation to locations, sizes, histomorphologies, histological differentiations, Dukes stages, and lymph node metastases of the lesion(P > 0.05). Exfoliative cytology had a 98.50% (131/133) specificity for colorectal cancer in the study. The sensitivity for colorectal cancer was no significant difference between the two methods of exfoliative cytology and FOBT (76.09% vs 84.78%, P > 0.05), but the specificity for colorectal cancer, exfoliative cytology was significant higher than FOBT(98.50% vs 73.68%, P < 0.05). 2. DNA analysis of exfoliated cells nuclear, DNA content, nuclear area, nuclear irregular index and percent of > or = 5C cells in the stool were significant higher in colorectal cancer than in control group(P < 0.05). The percentage of > or = 5C cells were significantly associated with histological grade (P < 0.05). CONCLUSIONS: 1. Detection of exfoliated cells in stool plays an important role in diagnosis of colorectal cancer. Testing of FOBT and exfoliated cells sequentially hopes to be a new useful non-invasive test for screening of colorectal cancer. 2. DNA analysis of exfoliated cell in stool may provide an objective method of determining malignant grades and diagnosis of colorectal cancer.
Adult↗
Study on the interaction between protein and Eu(III)-chlorotetracycline complex and the determination of protein using the fluorimetric method.
Chlorotetracycline (CTC) can react with europium ions Eu3+, and the complex emits the intrinsic fluorescence of Eu3+. The intensity is greatly enhanced by proteins and this forms the basis of a new fluorimetric method for determination of protein. Further research indicates that under optimum conditions, the enhanced intensity of fluorescence is in proportion to the concentration of proteins, in the range 2.0 x 10(-7)-1.0 x 10(-5) g/mL for bovine serum albumin (BSA) (linear equation, I(f) = 34.35933 + 11.54467 x 10(6)C)(r = 0.99895) and 8.0 x 10(-7)-1.0 x 10(-5) g/mL for human serum albumin (HSA) (linear equation, I(f) = 76.58881 + 5.3569 x 10(6)C) (r = 0.99283). Detection limits (S/N = 3) were 8.9 x 10(-9) g/mL for BSA and 3.3 x 10(-8) g/mL for HSA. In an assay for BSA in calf serum, this method gave a value close to that determined by the UV spectrophotometric method.
Buffers↗
A fluorimetric method for the determination of nucleic acids using Ce(IV) and sodium triphosphate.
A novel and stable fluorimetric method was established for the determination of nucleic acids. The proposed method is based on the reduction by nucleic acids of Ce(IV) to fluorescent Ce(III). The fluorescence intensity can be greatly increased by sodium triphosphate. The enhanced fluorescence intensity is proportional to the concentration of nucleic acids in the range 4.2 x 10(-8)-4.2 x 10(-6) g/mL for fish sperm DNA and 5.0 x 10(-8)-6.5 x 10(-6) g/mL for yeast RNA, and the detection limits (S/N = 3) are 13.5 ng/mL and 45 ng/mL, respectively. The reaction mechanism of the hydrolytic scission of nucleic acids by Ce(IV) is discussed.
Animals↗
Fluorescence enhancement effect of the morin-Al3+ -sodium dodecyl benzene sulphonate-protein system and the determination of proteins.
The fluorescence intensity of the morin-Al(3+) complex was greatly enhanced by proteins in the presence of sodium dodecyl benzene sulphonate (SDBS). Based on this, a new fluorimetric method for the determination of protein was developed. Under optimum conditions, the enhanced intensity of fluorescence was in proportion to the concentration of proteins in the range 1.0 x 10(-8)-1.3 x 10(-5) g/mL for bovine serum albumin (BSA), 4.0 x 10(-8)-1.2 x 10(-5) g/mL for egg albumin (EA) and 5.0 x 10(-8)-1.2 x 10(-5) g/mL for human serum albumin (HSA). Their detection limits (S:N = 3) were 5.0 x 10(-9), 1.8 x 10(-8) and 1.6 x 10(-8) g/mL, respectively. The interaction mechanism was also studied.
Aluminum↗
Resonance light scattering technique for the determination of proteins with Congo red and Triton X-100.
Resonance light scattering (RLS) of Congo red (CR) was greatly enhanced by BSA (HSA) in the presence of Triton X-100 (TX-100). In sodium citrate-HCl buffer (pH 2.7-3.0), the enhanced intensity of resonance light scattering at 360 nm was in proportion to the concentration of proteins [corrected] The linear relationship was obtained between the resonance light scattering intensity and proteins in the range 5.0 x 10(-8)-8.0 x 10(-6) g/mL and 1.0 x 10(-9)-6.0 x 10(-6) g/mL for BSA and HSA, respectively. Their detection limits were 1.4 x 10(-8) g/mL and 2.8 x 10(-10) g/mL (S:N = 3), respectively. Synthetic and actual samples were analysed satisfactorily.
Buffers↗
Determination of nucleic acids based on the quenching effect on resonance light scattering of the Y(III)-1,6-bi(1'-phenyl-3'-methyl-5'-pyrazolone-4'-)hexane-dione system.
Nucleic acids can quench resonance light scattering (RLS) intensity of the Y(III)-1,6-bi(1'-phenyl-3'-methyl-5'-pyrazolone-4'-)hexane-dione(BPMPHD) complex in the pH range 5.0-5.8. Under optimal conditions, there are linear relationships between the quenching of RLS and the concentration of nucleic acids in the range 6.3 x 10(-8)-2.1 x 10(-5) g/mL for fish sperm DNA (fsDNA), 1.2 x 10(-8)-5.0 x 10(-5) g/mL for calf thymus DNA (ctDNA) and 6.0 x 10(-8)-2.0 x 10(-5) g/mL for yeast RNA (yRNA). The detection limits (3 s) of fsDNA, ctDNA and yRNA are 0.7 ng/mL, 3.8 ng/mL and 4.2 ng/mL, respectively.
Aldehydes↗
Improvement of the acridine orange-protein-surfactant system for protein estimation based on aromatic ring stacking effect of sodium dodecyl benzene sulphonate.
The fluorescence of acridine orange (AO) is greatly quenched by the anionic surfactant sodium dodecyl benzene sulphonate (SDBS), but when protein is added into the AO-SDBS system, the fluorescence intensity of the latter is enhanced again. Based on this, a new fluorimetric method of determination of protein was developed. Under optimum conditions, the enhanced intensity of fluorescence is in proportion to the concentration of protein, such as bovine serum albumin (BSA), human serum albumin (HSA) and egg albumin (EA), over a wide range with detection limits at the 10(-9) g/mL level. This method has been satisfactorily used for the determination of protein in samples. We compared results using 280 nm and 490 nm excitation wavelengths and the mechanism of the assay.
Acridine Orange↗
The sensitive determination of nucleic acids using a fluorescence-quenching method.
Experiments indicated that nucleic acids can quench the fluorescence of the Eu3+ -2-thenoyltrifluoroacetone (TTA)-1,10-phenanthroline (Phen) system. Based on this, a sensitive method for the determination of nucleic acids was proposed. The experiments indicated that under the optimum conditions, the quenched fluorescence intensity was in proportion to the concentration of nucleic acids in the range 1.0 x 10(-11)-1.0 x 10(-6) g/mL for yeast RNA (yRNA), 5.0 x 10(-11)-5.0 x 10(-7) g/mL for fish sperm (fsDNA) and 1.0 x 10(-10)-1.5 x 10(-6) g/mL for calf thymus DNA (ctDNA). Their detection limits were 3.0 x 10(-12), 4.0 x 10(-12) and 5.0 x 10(-11) g/mL, respectively. Therefore, the proposed method is one of the most sensitive methods available. The interaction between nucleic acids and Eu3+ -TTA-Phen is also discussed.
Europium↗