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Biomedical subjects

S Tao

Publications and source records attributed to S Tao.

At least 73 records · Page 4Linked to original sources
PubMed2000

Uptake of cadmium adsorbed on particulates by gills of goldfish (Carassius auratus).

Goldfish (Carassius auratus) were exposed to mixtures of constant dissolved cadmium (0.01 mg/L) and cadmium adsorbed on gibbsite particles at concentrations of 0, 0.025, 0.050, 0.075, and 0.100 mg/L. The gills of the fish were excised after a 5-day exposure experiment and both cadmium and aluminum in the gills were measured. The gills were also examined with a light microscope for surface adherence of the particles after the exposure. The evidence collected demonstrated that the concentration of cadmium in the gills increased with increased concentration of particulate cadmium during the exposure while the dissolved cadmium remained constant. The ratio of cadmium to aluminum in the gills was apparently higher than that in the solution, indicating the stripping and translocation of cadmium from the particles. A multistep uptake process is proposed and the bioavailability of particulate cadmium to fish gills is discussed.

Adsorption↗
PubMed2000

Fragment constant method for prediction of fish bioconcentration factors of non-polar chemicals.

A fragment constant method for prediction of fish bioconcentration factor (BCF) was established based on experimental BCF values for 80 non-polar chemicals from nine classes. The model was evaluated using coefficients of determination and mean residuals, which are 0.995 and 0.1836, respectively. Jackknife tests were applied to examine the robustness of the prediction model on a class-by-class basis.

Animals↗
PubMed2000

Estimation of bioconcentration factors of nonionic organic compounds in fish by molecular connectivity indices and polarity correction factors.

A bioconcentration factor (BCF) estimation model for a wide range of nonionic organic compounds was developed on the basis of molecular connectivity indices and polarity correction factors. The nonlinear topological modeling using polarity correction factors resulted in the best BCF estimation quality for all of the 239 compounds studied, with a mean absolute estimation error of 0.478 log units. Residual analysis indicated that the estimation errors came from many sources including BCF measurement, test species, and selection of descriptors. Statistical robustness of the developed model was validated by modified jackknifed tests where random deletion of a set of compounds and specific deletion of a class of compounds were both performed. Comparison between the MCI-based (molecular connectivity indices) model and a Kow-based (octanol/water partition coefficient) model revealed that the BCF estimation based on topological parameters was as good as that achieved by Kow.

Animals↗
PubMed2000

Stephanotic acid, a novel cyclic pentapeptide from the stem of Stephanotis floribunda.

The stem of Stephanotis floribunda afforded a new cyclic pentapeptide stephanotic acid (1), possessing a novel 6-(leucin-3'-yl) tryptophan skeleton. The structure of 1 was assigned on the basis of extensive NMR experiments and a chemical reaction and shown to be closely related to the bicyclic octapeptide moroidin (3), a toxin from Laportea moroides.

Madagascar↗
PubMed2000

Calcaneus fractures with subluxation of the posterior facet. A surgical indication.

The charts and radiographs of 118 patients with 126 intraarticular fractures of the calcaneus were reviewed retrospectively. Eleven of 126 (8.7%) calcaneal fractures had injuries consisting of intraarticular calcaneal fracture, lateral subluxation or dislocation of the posterior facet, fracture extension into the calcaneocuboid joint, peroneal tendon subluxation, subluxation of the talus in the ankle mortise, and complete disruption of the anterior talofibular and calcaneal fibular ligaments or fracture of the lateral malleolus. There were six women and five men. The average age was 40 years (range, 17-65 years). The mechanism of injury was a motor vehicle accident in eight and a fall from a height in three. According to the classification of Sanders et al eight fractures were Type II, one was Type III, and two were Type IV. Followup at an average of 26 months (range, 14-38 months) showed that eight of 11 patients (72.7%) had either good or excellent results. When lateral subluxation of the posterior facet of the calcaneus is identified with a preoperative computed tomography scan, operative management is indicated, and the surgeon should search for associated injuries that should be addressed at the time of surgery.

Adolescent↗
PubMed2000

LMP2 polymorphism is associated with extraspinal disease in HLA-B27 negative Caucasian and Mexican Mestizo patients with ankylosing spondylitis.

OBJECTIVE: To determine the effects of HLA Class II genes, particularly LMP2 and previously implicated Class I genes, on susceptibility and disease expression in HLA-B27 negative ankylosing spondylitis (AS). METHODS: Patients included 41 HLA-B27 negative Caucasians from a total AS population of 546 and 17 HLA-B27 negative Mexican Mestizo. Controls included 4352 random HLA-B27 negative Caucasians. LMP2 genotype assignments were made on all patients and 282 random Caucasian controls by polymerase chain reaction-restriction fragment length polymorphism with the Cfo I restriction enzyme while HLA typing was performed on patients and controls using microcytotoxicity assays for Class I, and sequence specific probe-PCR for HLA-B60, B39, B38, and DR. RESULTS: The LMP2BB genotype was significantly decreased in Caucasian AS patients without extraspinal (ES) disease (25%) compared to AS patients with ES (64.7%) (p = 0.01) and random Caucasian controls (53.9%) (p = 0.007), even when those with colitis and psoriasis were excluded from analysis (ES+ 55.6% versus ES- 22.2%). This finding remained significant after stratification by HLA-DR. Similar trends were noted in the Mexican population. A potential role for HLA-DR8 and DR2 in susceptibility to disease was observed in Caucasian patients, although this observation requires confirmation. We could not confirm reported associations with HLA-B60 or B39. Peripheral arthritis was significantly more commonly observed in those who had had acute anterior uveitis (AAU) (75%) than in those who had not developed AAU (27.3%) (p = 0.04). CONCLUSION: HLA Class II encoded genes may have effects on disease susceptibility and/or phenotype in HLA-B27 negative individuals similar to those noted in HLA-B27 positive AS. Eccentric and axial phenotypes of disease may be immunogenetically determined.

Adult↗
PubMed2000

Progress in the molecular genetic research of multinodular goiter.

Multinodular goiter is a worldwide-distributed disease, but yet its pathology and genetic etiology are not clear. At present, most researches have been restrained to traditional epidemiological survey and the disease has been rarely studied at the level of molecular genetics. The pathogenesis of multinodular goiter, as is generally accepted by most researchers, can be attributed to many factors such as hormones, growth factors and the inherent functional heterogeneity of thyroid follicles. Since hormone and iodine metabolization are widely recognized as a major mechanism in determining the formation of multinodular goiter, some reports in literature are mainly focused on such genes that are responsible for hormone synthesis and iodine metabolization. Mapping experimental data were available to support location of multinodular goiter gene(s) onto chromosome 14q by whole genome scanning in a large pedigree analysis. Additional data, particularly those extracted from large scaled marker-assisted mapping experiments, are important so as to confirm the gene location, to improve resolution of the location, and finally to dissect the genes underlying the disease at molecular level.

Chromosome Mapping↗
PubMed2000

[Prediction of bioconcentration factors of organic compounds in fish by molecular connectivity indices and function correction factors].

Studies on the prediction models of bioconcentration factors(BCF) of 239 organic compounds showed that the BCFs of polar organic compounds could not be accurately predicted solely by the linear model based on molecular connectivity indices. Additionally, the linear model was not suitable for superphilic compounds. By introducing function correction factors to the model, the residual of the prediction model for polar organic compounds was reduced significantly. When the nonlinear estimation was used, the accuracy of the obtained model was further improved. The final prediction model consisted of parameters (0 chi v)2, (2 chi v)1/2, 2 chi, 3 chi c, 0 chi v and 10 correction factors for function groups OH, NH2, NO2, NCOO, etc. The difference between calculated and observed values of logBCF and its causes were analyzed. The robustness of the model was tested by Jackknifed method, based on random grouping and compound classification.

Animals↗
PubMed2000

[Uptake of particulate lead via gills of goldfish].

This paper studied the uptake of Pb absorbed on suspended gibbsite via gills of goldfish (Carassius auratus). Under conditions of the concentration of the particulate Pb varied while that of free Pb maintained at a constant level, the levels of both Pb and Al in the gills increased with increasing exposed Pb concentration. The increasing rate (slope 0.171) of Pb level in the blood with the Pb level in the gills was lower than that (slope 0.343) of soluble Pb exposure experiment. Partial Pb adhered on the gills did not transfer into blood. The ratio of Pb/Al in the gills was 1-2 orders of magnitude higher than that in the water, and on the microtome section of filament, the gibbsite particles adhered on gill mucus were observed, indicating the bioavailability of the particulate Pb uptake by the gills of goldfish. The major mechanism was: when the absorbed Pb on suspended particles was flowed into gill filaments, it was desorbed on the surface of gills, and then, passively diffused or transferred by carriers via gill cells into flood, and after the particles stayed on the surface of gill filaments for a short time, in company with sloughed mucus, they were released from the gills along with waterflow.

Absorption↗
PubMed2000

[Effect of rhizospheric environment of VA-mycorrhizal plants on forms of Cu, Zn, Pb and Cd in polluted soil].

Maize (Zea mays L.) was inoculated with or without VA mycorrhizal (Glomus mosseae) and cultivated in a heavy metals contaminated soil. The distribution and dynamics of Cu, Zn, Pb and Cd forms in rhizosphere of maize inoculated with or without VA-mycorrhizal were analyzed with the technique of sequential extraction. Comparing with control soil, exchangeable Cu in rhizospheric soil increased significantly, and the exchangeable Cd trended down. In rhizosphere of VA-mycorrhizal maize, the amounts of Cu, Zn and Pb bound to organic matter were significantly higher than those in rhizosphere of non-mycorrhizal maize, while the four tested metals bound to carbonates and to iron and manganese oxides were constant in rhizosphere of mycorrhizal and non-mycorrhizal maize. These results illustrated that the plant roots could influence the distribution and dynamics of metal forms in rhizosphere, and much for mycorrhizal plants than for non-mycorrhizal plants. At excessive concentration of soil metals, mycorrhizal roots might decrease the bio-availability of toxic heavy metals by changing their forms. The factors that caused the change of metal fractions in rhizosphere of mycorrhizal and non-mycorrhizal plants were also discussed.

Cadmium↗
PubMed2000

[Interaction of Cu and Pb in accumulation process by fish].

With synthetic water, the accumulation of co-existed Ca and Pb by Paracheirodon innesvi and of Pb by Cu-tamed P. innesvi was studied. The result showed that under both conditions, there existed a significant synergistic effect on the accumulation of Cu and Pb by the fish.

Animals↗
PubMed1999

[New subtype of coltivirus isolated from mosquitoes in the northeast part of China].

OBJECTIVE: The purpose of this study was to isolate new arbovirus from mosquitoes collected from the northeast part of China during the summer of 1996. METHODS: The cell used for isolation were C6/36 and BHK-21 cells. RESULTS: Two strains (NE97-12 and NE97-31) of coltivirus were isolated among 68 mosquito specimens. The viruses caused cytopathogenic effects on C6/36 cell, but not on BHK-21 cells. They were resistant to both 5-IDU and ether, but sensitive to pH3.0 and temperature at 56 degrees C for 30 minutes. IFA of new isolates with mouse ascitic fluid anti-coltivirus TRT2 strain showed positive reaction. Polyacrylamide gel electrophoresis (PAGE) of two isolates showed 12 segments of double-stranded(ds) RNA and PAGE profiles were 6-5-1, which were different from that of coltivirus TRT2 strain(6-6). There was no cross neutralization between new isolates and TRT2 strain by tissue culture cross-neutralization test. CONCLUSION: The results indicated while new isolates were serologically related to TRT2 strain of coltivirus by IFA, the neutralization test suggests that it represents a distinct serotype. These new isolates isolated firstly from the northeast part of China belong to a new subtype of coltivirus.

Animals↗
PubMed1999

Synergistic effect of copper and lead uptake by fish.

Paracheirodon innesi was exposed (simultaneously or sequentially) to copper and lead in varying concentrations in a synthetic water solution. Metal accumulations in fish gills and the fish (without gills) were measured at the end of the exposure period. Results of the exposure experiment indicated that lead seems to facilitate the uptake of copper and vice versa when the exposure process is simultaneous. In the case of sequential exposure first to copper for 7 days then to lead for 20 days, lead accumulations in the fish and the gills were enhanced by copper, indicating a possible alteration of the physiological absorption process. The synergistic effects observed during either simultaneous or sequential exposure experiments can be described using logistic equations.

Animals↗
PubMed1999

Uptake of particulate lead via the gills of fish (Carassius auratus).

Carassius auratus were exposed to mixtures of constant free lead (0. 1 mg/L) and particulate lead (adsorbed on gibbsite particles) at varied concentrations (0, 0.4, 0.8, 1.2, 2.0, and 3.0 mg/L). The concentrations of lead and aluminum in the gills and intestines of the fish were determined after exposure. The gills were examined (after the exposure) with a light microscope for any particles adhering to the surface. The examination results revealed that lead accumulations on the gills increased with increased particulate lead concentrations in the ambient water (under conditions of a constant level of free lead), indicating the bioavailability of lead via the gills. Gibbsite particles were also observed on the gill surface after exposure. The ratio of lead and aluminum in the gills was much higher than that in the particles. Our results suggest that there was a two-step process involved in the uptake of particulate lead by fish gills: (1) adherence of the particles on the gill surface where mucus was attached; and (2) desorption of lead from the particles under conditions of the gill microenvironment.

Animals↗
PubMed1999

Prediction of fish bioconcentration factors of nonpolar organic pollutants based on molecular connectivity indices.

The relationship between bioconcentration factors and molecular connectivity indices was investigated. A regression model was developed using 80 measured BCFs of nonpolar organic pollutants. The five topological parameters used were 1 chi, 2 chi, 3 chi c, 0 chi v and 2 chi v. Modified jackknife tests were applied to examine the robustness of the model by repeatedly removing a set of or a class of compounds from the database. The model was compared with one using Kow as an independent parameter. The mean absolute errors for the 80 compounds studied were 0.288 and 0.302 log-unit for the two models, respectively.

Animals↗
PubMed1999

Leaching kinetics of water soluble organic carbon (WSOC) from upland soil.

The kinetics of the leaching process of Water Soluble Organic Carbon (WSOC) from an upland soil were studied in a column leaching experiment. The pattern of the leaching curve indicated multiphasic release kinetics. A conceptual model was proposed to divide capillary and gravitational pores. The translocation of organic carbon in soil during leaching occurs in four sequential steps. 1) degradation of insoluble organic carbon to form WSOC; 2) desorption into capillary pore water; 3) diffusion towards gravitation pore water; and 4) leaching by convection flow. The overall kinetics of the leaching process can be depicted using an equation with three additive terms for degradation, desorption/diffusion, and convection, respectively.

Carbon↗