Biomedical subjects

S Yue

Publications and source records attributed to S Yue.

At least 37 records · Page 2Linked to original sources

PubMed1999

[Separation and selection of salivary adhesion receptors of Streptococcus mutans to tooth surface].

OBJECTIVE: To select and purify salivary receptors of Streptococcus mutans from experimental salivary acquired pellicle. METHODS: Experimental salivary acquired pellicle (SAP) was performed by coating hydroxyapatite (HA) with whole saliva. Then SAP was washed from HA by 1 mol/L NaCl and 0.5 mol/L phosphate buffer sequentially. The proteins were further separated by chromatography of Sephadex G75 and DEAE-Sephadex A25. Receptors of Streptococcus mutans were selected by bacterial adhesion test and competitive inhibition adhesion test. Identification was performed by PAGE, SDS-PAGE, IP-PAGE and detection of amylase activity and inmunodifusion test. RESULTS: IgA degraded fragments, a protein of 13 kD and amylases were the receptors of S. mutans. The first two only promote the adhesion but the amylases can both promote and inhibit S. mutans adhesion. CONCLUSION: The adhesion of S. mutans to tooth surface is a result of interaction between adhesins of S. mutans and multiple salivary receptors.

Adhesins, Bacterial↗

PubMed1999

[A study on biological properties of fimbriae of Actinomyces viscosus. II. Chemical characteristics of fimbriae of A. viscosus].

OBJECTIVE: To investigate the chemical characteristics of two purified fimbriae. METHODS: The specific antibodies against type I and type II fimbriae of A. viscosus were prepared and the purity of the two purified fimbriae had been identified by the specific antibodies. Then, chemical analysis and amino acid analysis of the two purified fimbriae were done. RESULTS: The two purified fimbriae were mainly composed of proteins and small amount of carbohydrate. The two types of fimbriae contained large amounts of aspartic acid, glutamic acid, alanine, lysine and glycine, and high percentage of nonpolar amino acid was analysed while basic amino acids were present in a very small amounts. CONCLUSION: These results may help to understand the relationship between the chemical characteristics of two types of fimbriae and their biological activity.

Actinomyces viscosus↗

PubMed1999

[A study on biological properties of fimbriae of A. viscosus. III. Adherence activity of fimbriae of A. viscosus].

OBJECTIVE: To investigate the adherence activity of two types of fimbriae of A. viscosus on tooth surface or with S. sanguis 34. METHODS: The inhibited adherence tests, coaggregation tests and the inhibited coaggregation tests were done. RESULTS: 1. The purified type I and type II fimbriae inhibited the adherence of A. viscosus to salivary-treated hydroxyapatite (SHA) and the two specific IgG to type I and type II fimbriae blocked the adsorption of strain T14V, strain 5519 and strain 5951 to SHA; 2. Only type II fimbria indirectly mediated the visible agglutination of S. sanguis 34 and only IgG to type II fimbriae inhibited coaggregation of strain T14V and strain 5915 with S. sanguis 34. CONCLUSION: Type I and type II fimbriae have adherence ability, and only type II fimbria has the agglutination activity. Additionally, the methods which were used to prepare fimbriae don't damage the biological activity of fimbriae.

Actinomyces viscosus↗

PubMed1998

[Determination of salidroside in eight Rhodiola species by TLC-UV spectrometry].

Quantitative determination of the salidroside in eight Rhodiola species by TLC-UV spectrometry is reported. The salidroside was separated on a silica GF254 TLC plate using CHCl3-CH3OH-H2O(26:14:3) as developing solvent and determined at wavelength 223.8 nm. The results show that this method in simple and convenient.

Chromatography, Thin Layer↗

PubMed1998

[Living related liver transplantation: a case report].

OBJECTIVE: To study a case of living related liver transplantation. METHOD: The patient was a 10-year-old girl who suffered from congenital diffuse intrahepatic cholangiectasis, recurrent cholangitis and hepatocirrhosis. The donor was the patient's father aged 40. The left lateral lobe of donor's liver was cut and grafted to the patient. Intensive care and treatment as well as follow-up were given after operation. RESULT: For the donor, the operation lasted 400 min, with 410 ml bleeding and 300 g liver removed. The recovery was satisfactory. For the recipient, the operation lasted 652 min, with 1665 ml bleeding, 80 min non-liver stage, 0 min graft hot ischemic stage, and 137 min cold ischemic stage. Immunosuppressive therapy was given using cyclosporin A, azathioprine and adrenocortical hormones. There was an acute rejection 11 days after operation, which was controlled using hormone impulsive therapy. The patient has been surviving 7 months with normal liver function. CONCLUSION: The living related liver transplantation is feasible under modern surgical conditions. It is demonstrated that perfect postoperative management is the key for the successful liver transplantation.

Adult↗

PubMed1998

[Study on the adhesion of an endemic strain of Streptococcus mutans serotype C to acquired pellicle. I. A comparison of the methods to extract adhesins from Streptococcus mutans].

The adhesins of S. mutans serotype c endemic strain WD9463A were extracted from culture superant by cold ethol precipitation, or were extracted from cell surface by 0.5 mol/L phosphate buffer, 6 mol/L urea or 2% SDS solution. The composition and adhesive activities of the extracts were compared by SDS-PAGE and bacterial adhesion inhibition experiments. The results showed that the protein composition of the four extracts were similar, and all extracts inhibited the adhesion of the endemic strain dramatically. It indicates that four methods can be used to extract adhesins of S. mutans, but extracting adhesins from culture superant is better than the others.

Adhesins, Bacterial↗

PubMed1998

[Study on the adhesion of an endemic strain of Streptococcus mutans serotype C to acquired pellicle. II. Isolation and extraction of adhesins of an endemic strain of Streptococcus mutans serotype C].

Surface proteins of S. mutans WD9463 A(c) were separated by DEAE-Sephadex A25 Chromatography and Sepharose C1-6B Chromatography. The adhesins were distinguished by bacterial adhesin inhibition experiment and were identified by PAGE, SDS-PAGE, IEP-PAGE, immunol diffusion test, GTF activity test and annalization of the sorts of amino acid. The results showed P1, two proteins with molecular weight of 117 kD and 127 kD and two proteins with GTF activity could inhibit the adhesion effectively. On the other hand, another kind of GTF could improve the adhesion of the strain. These indicated that S. mutans may be many kinds of adhesins.

Adhesins, Bacterial↗

PubMed1998

[Comparison of demineralization of different organic acid to enamel].

The rates of demineralization of 5 organic acids (mathanoic acid, formic acid, propionic acid, Lactic acid, acetic acid, mixed acid) to the bovine enamel were tested and analysed with the self-made calcium ionselective microelectrodes(Ca(2+)-ISME) basing on a neutral carriers of ETH1001. The results showed; 1. The difference between the rates of demineralization of formic acid and lactic acid, formic acid and propionic acid, formic acid and acetic acid, acetic acid and mixed acid, acetic acid and lactic acid, propionic acid and mixed acid, propionic acid and lactic acid, lactic acid and mixed acid were of great significance (P < 0.01); 2. The rates of demineralization of acetic and mixed acid decreased with time, due to saturation of the solution during demineralization; 3. Ca(2+)-ISME was of the advantages of simplicity, rapidity, sensitivity and accuracy. The results suggest that the cariogenic potential is related to different acid products of different cariogenic bacteria, and the degree of mineral saturation within solution affects the rate of demineralization.

Acetic Acid↗

PubMed1997

Interaction of sodium chloroplatinate and iproplatin with metallothionein in vivo.

The abilities of platinum(IV) complexes to induce the biosynthesis of metallothionein (MT) were investigated in rabbits given injections s.c. of sodium chloroplatinate (Na2PtCl6) and iproplatin (cis-dichloro-bis-isopropylamine-trans-dihydroxylplatinum IV). It is revealed for the first time that both complexes can induce MT synthesis in the liver and the kidney, but the induction ability was weaker compared to Zn2+ compounds. The induced MT was purified and identified. The hepatic MT resulting from Na2PtCl6 injection only contained Zn, whereas the hepatic MT from iproplatin injection and the renal MT from injection of both complexes contained 4-5 Zn and 1-2 Pt per mole of protein, and the renal MT also contained 1-2 Cu per mole of protein. The oxidation state of platinum in the MT is +2 as determined by X-ray photoelectron spectroscopic measurements. Pretreatment with Zn(NO3)2 elevated the levels of MT, but the binding of Pt to MT was significantly less compared to that without Zn(NO3)2 pretreatment. The data obtained from the amino acid composition analysis were consistent with the theoretical values. Upon these bases, the role of MT in relation to its involvement in the metabolism of Pt(IV) complexes and the mechanism of drug resistance to the Pt(IV) complexes as antitumor agents are discussed.

Animals↗

PubMed1997

Reaction of a platinum(IV) complex with native Cd,Zn-metallothionein in vitro.

The first observation of a redox process following a substitution reaction between a platinum(IV) complex K2PtCl6 with rabbit liver native Cd,Zn-MT is presented. The reaction features and products are studied by UV-visible and circular dichroism spectroscopy, chromatography, and X-ray photoelectron spectroscopic measurements. It is a significant complicated reaction comprising redox and substitution reactions. The reaction generates monomeric and dimeric products, and higher oligomers precipitate with intra- or intra- and intermolecular CyS-SCy linkages. Pt(IV) is reduced to Pt(II), which then binds to the monomeric and dimeric products, and may also bind to higher oligomers. The beta-cluster is more reactive than the alpha-cluster, and reacts first with K2PtCl6. Cd5Pt2 and Cd4Pt4 were found when native Cd,Zn-MT reacted with 2 and 4 molar equivalents of Pt(IV) for 2 h in which four Cd ions were located in the alpha-cluster. The amounts of Cd and Pt ions decreased in both monomeric and dimeric products when the reaction was prolonged and intramolecular CyS-SCy linkages increased. Besides the oligomers which precipitated, only dimeric products were formed when the reaction molar ratio of Pt(IV) to MT was more than 10:1. Cd3Pt6 and Cd1Pt8 were obtained when the reaction occurred for 2 and 72 h, respectively. The structure of the clusters may exist when native Cd, Zn-MT reacts with substoichiometric quantities of K2PtCl6 (< 0.5 K2PtCl6 per MT thiolate) for a short time (2 h), but may be partly disrupted with stoichiometric or excess quantities of K2PtCl6 (> or = 0.5 K2PtCl6 per MT thiolate) for a long time. The disruption of the cluster structures results in an increase of the nonbridge thiolate and an increase of the binding sites to Pt ions. The mechanism of the antitumor activity and developing drug resistance of Pt(IV) complex drugs is discussed.

Animals↗

PubMed1997

The effect of heat treatment on the fatigue strength of microknurled Ti-6Al-4V.

Microknurling, a high pressure surface indentation technique, was devised as an alternative to traditional heat-bonded porous coatings found on many orthopedic implants designed for fixation by tissue ingrowth. Heat-bonded porous coating can cause at the surface of an implant stress concentrations that reduce fatigue strength. However, microknurling may reduce stress intensification without eliminating it. Thus the purpose of this work was to explore surface thermal/mechanical processing of Ti-6Al-4V to improve the fatigue strength of microknurled specimens via the production of a Ti-6Al-4V dual microstructure. The latter consists of a surface layer of equiaxed grains known to be effective against crack initiation and a bulk microstructure of lamellar grains that possesses optimum fatigue crack propagation resistance. Rotating-bending fatigue tests showed that such a microstructure had some benefits, but this was offset by the reduction in compressive strains imparted to the surface by the heat treatments needed to obtain this microstructure.

Alloys↗

PubMed1997

Fatigue fracture of a forged cobalt-chromium-molybdenum femoral component inserted with cement. A report of ten cases.

Ten patients who had had a total hip replacement with a forged cobalt-chromium-molybdenum femoral prosthesis (Precoat or Precoat Plus) inserted with cement were seen with a fatigue fracture of the stem an average of fifty months (range, nineteen to seventy-four months) postoperatively. The average age of the patients was sixty-one years (range, forty-three to seventy-three years), and the average weight was ninety-six kilograms (range, seventy to 130 kilograms). Eight patients had had a primary total hip replacement, and two had had a revision; all of the acetabular components had been inserted without cement. Radiographs that had been made before the fracture were available for four of the eight hips that had had a primary replacement; all four had radiographic evidence of debonding of the cement mantle from the proximal end of the stem. This probably caused exaggerated cantilever bending stresses on the proximal aspect of the stem as the distal end of the stem was well fixed. The radiographs of both hips that had had a revision demonstrated a non-union of the greater trochanter, which had resulted in separation at the cement-bone interface at the proximal portion of the femur before the fracture. Scanning electron micrographs of five of the ten fractured prostheses demonstrated a fatigue fracture that began near the anterolateral corner of the prosthesis, through characters that had been etched on the implant with a laser. Metallurgical analysis indicated subsurface voids or inclusions, or both, immediately under the region that had been etched. This finding is consistent with thermal changes to the microstructure of the alloy that probably caused a focal reduction in the material strength. A high proportion (seven) of the ten stems had a poor cement mantle. Also, of the seven small stems that were used, six had been implanted in patients who weighed more than eighty kilograms, so there was relative undersizing of the prostheses. Early debonding of the proximal end of a Precoat femoral prosthesis from the cement mantle may occur as a result of a thin cement mantle, leading to loosening and possibly to early fatigue fracture of the stem if the distal portion of the stem remains solidly fixed in the distal portion of the cement column. On the basis of our experience, we recommend that patients who have radiographic evidence of a debonded Precoat femoral component should be informed of the risk of fatigue fracture of the stem and be followed closely even though there may be no symptoms of loosening of the femoral component.

Adult↗

PubMed1997

[The immune response in rats immunized systemically by the surface protein antigen P1 from streptococcus mutans conjugated with procholeragenoid].

This study was carried out to observe the antibody responses in rats after they were immunized with the surface protein P1 of streptococcus mutans when a special adjuvant was used. Antigen P1 was conjugated covalently with procholeragenoid (PCG), and then Sprague Dawley rats were immunized with P1 or the conjugated antigen P1-PCG subcutaneously or intragastrically. Anti-P1 antibody level was assayed at different time points by ELISA. The results showed that the levels of anti-P1 SIgA antibody in saliva rose when P1-PCG was given subcutaneously or intragastrically; the antibody level following the subcutaneous injection was higher and lasted longer, compared with that following the intragastric administretion. The level of anti-P1 IgG antibody in serum only rose when the rats were immunized subcutaneously. These results implied that mucosal immune response or humoral immune response could be induced subcutaneously when PCG was used as an adjuvant.

Animals↗

PubMed1997

[The study of actinomyces viscosus adhere to teeth. III. The identification of mutants of A. viscosus and preparation of rabbit IgG against type 1 and type 2 fimbriae].

The authors prepared rabbit antisera against 5519 and 5951. The IgGs against type 1, type 2 fimbriae were purified from the antisera using sera absorbed with the other strain and IgG purification method. It was identified by SDS-PAGE and ELISA. This result suggested the purified proteins were the IgG against type 1 and type 2 fimbriae.

Actinomyces viscosus↗

PubMed1997

[The study of actinomyces viscosus adhere to teeth. IV. The study of salivary protein receptors of A. viscosus].

In order to determine the receptors of A. viscosus for adhesion, 7 kinds of main purified proteins from pellicle formed by whole saliva were tested. The result indicated that: 1. APRP, statherin, PRPG and SIgA were the receptors of standard and fresh isolated A. viscosus; 2. APRP and stather promoted the adherence of 5519 (1+2-) to HA, and SIgA promoted the adherence 5951 (1-2+) to HA; PRPG was the common receptor of the two fimbriae. It suggested that there were receptors not only type 1 fimbriae but also type 2 in pellicle. Two types of fimbriae were involved in the adherence of A. viscosus to pellicle. The difference existed in the receptor of adherence and the activity site of the same receptor.

Actinomyces viscosus↗

PubMed1996

Reaction of metallothionein with ethylenediamine-N,N,N',N'-tetraacetic acid.

The reactions of various rabbit MTs (Cd7Th, Zn7Th, Hg7Th, Bi7Th, Pb7Th) with EDTA were studied at different pH and EDTA concentrations, and were determined to be pseudo-first-order reactions. The reactions were all divided into two steps: one faster and EDTA-dependent, and the other EDTA-independent. The mechanism is also described in detail. Based on obtained results, the varied induction behaviors of MT formation for those metals are discussed.

Animals↗

PubMed1996

Engineering issues and wear performance of metal on metal hip implants.

A major concern in total hip arthroplasty is the generation of polyethylene wear particles at the articulating surfaces and resulting macrophage mediated periimplant osteolysis. There is renewed interest in metal on metal bearings as a solution to this problem in view of their potential for greatly improved wear performance. Using a commercially available hip simulator, the wear performance of metal on metal femoral head and acetabular cup combinations was evaluated and various parameters affecting metal on metal implant wear were identified. Nine implants custom manufactured from 2 medical grades of CoCrMo alloy (ASTM F1537-95 and F75-92) were tested within bovine serum as the lubricant to 3 million cycles (equivalent to approximately 3 years of service in vivo). The progressive wear of the components was determined by gravimetric methods at approximately every 300,000 cycles. The wear rates were characterized by an initial period of accelerated wear after which a lower steady state wear rate was observed for subsequent cycles. The presence of calcium phosphate films on the component surfaces, the microstructure of the lower carbon, wrought alloy, and increased effective radii (decreased diametral clearances) were identified as factors that may be favorable to improved wear performance. The extent of the effect on wear of each parameter, however, cannot be discerned at this point and necessitates a study in which parametric changes are more tightly controlled. The present study suggests that the use of metal on metal articulating surfaces may mitigate the problem of osteolysis by offering improved wear performance.

Hip Prosthesis↗

PubMed1996

[The electron microscopic observation of the effect of monoclonal antibody on the form and structure of mutans streptococci OMZ176].

The effect of monoclonal antibody on the form and structure of Mutans Streptococci OMZ176 was studied. The result showed that a great number of Mutans Streptococci OMZ176 was agglutianated after treating with monoclonal antibody prepared by a cell wall protein antigen (molecular weight 220 kd) of Mutans Streptococci OMZ176. Bacterial cells were swollen obviously. The gap between cell wall and cytoplasmic was widened. The electronic density of cell plasm was greatly decreased.

Antibodies, Monoclonal↗