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At least 163 records · Page 9Linked to original sources

PubMed2006

Bone-like apatite coating on Mg-PSZ/Al2O3 composites using bioactive systems.

A biomimetic method was used to promote bioactivity on zirconia/alumina composites. The composites were composed of 80 vol% Mg-PSZ and 20 vol% Al2O3. Samples of these bioinert materials were immersed in simulated body fluid (SBF) for 7 days on either a bed of wollastonite ceramics or bioactive glass. After those 7 days, the samples were immersed in a more concentrated solution (1.4 SBF) for 14 days. Experiments were also performed without using a bioactive system during the first stage of immersion. A bone-like apatite layer was formed on the surface of all the materials tested, using wollastonite the bioactive layer was thicker and its morphology was close to that observed on the existing bioactive systems. A thinner apatite layer consisting of small agglomerates was obtained using bioactive glass. The thickness of the ceramic layers was within the range of 15 to 30 microm.

Alloys↗

PubMed2006

Study of yttrium containing bioactive glasses behaviour in simulated body fluid.

The influence of yttrium oxide on the bioactivity of glasses in the system SiO(2)-Na(2)O-P(2)O(5)-CaO-B(2)O(3)-K(2)O-MgO was studied in a simulated body fluid (SBF). Two series of glasses with different bioactivity were investigated. The reaction layers formed on the surface of the exposed glasses were evaluated by means of back scattered electron imaging of scanning electron microscopy equipped with energy dispersive X-ray analysis (BEI-SEM/EDXA). The concentration of Y, Ca and P released from the glasses into SBF, during 21 days was determined using inductively coupled plasma-emission spectroscopy ICP-AES and inductively coupled plasma-mass spectroscopy ICP-MS. Introducing yttrium in the selected bioactive glass tended to diminish the bioactivity of the glasses. The thickness of the calcium phosphate layer decreased with increasing yttrium oxide content. The same effect was also observed when yttrium oxide partially replaced only calcium, magnesium and phosphorous oxide in the precursor glass. The data show that we can produce bioactive glasses with yttrium oxide as a component. By suitable tailoring of the rest of the glasses the yttrium effect on the glass behavior in SBF should be possible to control and thus produce yttrium containing glasses with desired bioactivity.

Biocompatible Materials↗

PubMed1995

Reduction of tumor necrosis factor-alpha bioactivity by a human ovarian epithelial cancer cell line in vitro.

OBJECTIVE: Our purpose was to determine the ability of an ovarian epithelial carcinoma cell line, Caov-3, to alter the bioactivity of exogenously added tumor necrosis factor-alpha. STUDY DESIGN: Caov-3 cells were cultured for up to 6 days in Dulbecco's modified Eagle's medium containing 10% fetal calf serum. The control and tumor necrosis factor-alpha-treated cells were analyzed for proliferation, distribution throughout the cell cycle by flow cytometry, their ability to release bioactive tumor necrosis factor-alpha by L929 bioassay, and their ability to release immunoreactive tumor necrosis factor-alpha by a specific double sandwich enzyme-linked immunosorbent assay. RESULTS: Tumor necrosis factor-alpha induced a dose- and time-dependent inhibition of cell proliferation accompanied by accumulation of cells in late S and G2/M phases of the cell cycle. Tumor necrosis factor-alpha bioactivity was undetectable in the media of control Caov-3 cell cultures, but these cells exhibited TNF-alpha messenger ribonucleic acid. After culture of the cells for 2 days in the presence of various doses of TNF-alpha (0.1, 1.0, 10, or 100 ng/ml), a significant decline (p < 0.01) in bioactivity was observed in all groups with the exception of 100 ng of TNF-alpha. Further declines in bioactivity were observed 2 and 4 days later. Addition of TNF-alpha to Caov-3 cells did not affect its immunoactivity, and Western blots of media revealed major bands of immunoactivity at approximately 17 kd, the expected molecular size of TNF-alpha. CONCLUSION: These results indicate that Caov-3 ovarian carcinoma cells reduce the bioactivity of TNF-alpha, an important growth regulator, by a novel yet unknown mechanism to escape the modulatory effects of the normal immune response during cancer cell growth.

Animals↗

PubMed1992

The effect of enzyme induction on the cytochrome P450-mediated bioactivation of carbamazepine by mouse liver microsomes.

Predisposition to idiosyncratic toxicity with carbamazepine is thought to be due to a deficiency of the detoxication enzyme, microsomal epoxide hydrolase, although in some cases, concurrent administration of enzyme inducers might be a contributory risk factor, by altering the critical balance between bioactivation and detoxication. In this study, a mouse model has been used to determine the factors affecting carbamazepine bioactivation, using covalent binding and cytotoxicity as markers of bioactivation in vitro. Microsomes prepared from mice pre-treated with phenobarbitone increased (relative to the control microsomes) the formation of cytotoxic (12.3% vs 3.2%), protein-reactive (3.0% vs 2.0%) and stable (33.8% vs 18.1%) metabolites of carbamazepine. Similarly, pre-treatment with dexamethasone also increased the formation of the cytotoxic (24.8% vs 6.7%), protein-reactive (2.8% vs 1.5%) and stable (38% vs 19.8%) metabolites of carbamazepine, while beta-naphthoflavone pretreatment did not increase the formation of either the toxic or stable metabolites of carbamazepine when compared with its control microsomes. Co-incubation with gestodene (10-250 microM) resulted in a dose-dependent inhibition of both the bioactivation of carbamazepine and the formation of its stable 10,11-epoxide. SDS-PAGE and immunoblotting of the microsomes with anti-CYP3A antibody revealed the presence of a 52 kDa protein band in each preparation of microsomes, but the relative intensities of the bands, as measured by laser densitometry, were highest with the phenobarbitone and dexamethasone microsomes. The microsomal oxidation of cortisol to 6 beta-hydroxycortisol was also enhanced by pretreatment of mice with phenobarbitone (6.5% vs 2.7%) and dexamethasone (8.2% vs 4.3%), but not beta-naphthoflavone (2.2% vs 1.6%), when compared with their respective control microsomes, and was inhibited (range 25-68% inhibition), with all the microsomes by gestodene (50 microM). Taken collectively, the data in this study demonstrate that in the mouse, induction of the CYP3A subfamily significantly increases carbamazepine bioactivation. It is likely that in humans inducers of the orthologous form of this enzyme, most notably anticonvulsants, may increase the bioactivation of carbamazepine.

Animals↗

PubMed1993

Interaction of caffeine with acetaminophen. 1. Correlation of the effect of caffeine on acetaminophen hepatotoxicity and acetaminophen bioactivation following treatment of mice with various cytochrome P450 inducing agents.

The combination of caffeine with acetaminophen (APAP) is used widely in the treatment of headache. The effects of caffeine on APAP-induced hepatotoxicity and APAP bioactivation by liver microsomes from uninduced mice and from mice pretreated with various agents that induce cytochrome P450 were studied. When 1 mM caffeine was included, the rate of glutathione-APAP conjugate (GS-APAP) formation was increased significantly by 33 and 39% in microsomes from phenobarbital (PB)- and dexamethasone (DEX)-treated mice, respectively, whereas this parameter was decreased 39 and 12% by caffeine in microsomes from beta-naphthoflavone (beta NF)- and acetone-treated mice, respectively. A 5 mM concentration of caffeine increased GS-APAP formation by 47, 107 and 117% in microsomes from control, PB-, and DEX-treated mice, respectively, and decreased it 39 and 25% in microsomes from beta NF- and acetone-treated mice, respectively. Caffeine was a competitive inhibitor of APAP bioactivation in microsomes from beta NF- and acetone-treated mice. While caffeine increased APAP bioactivation in microsomes from uninduced, PB-, and DEX-treated mice, the apparent Km values for APAP were increased by caffeine, indicating that this enhancement was not due to a direct effect of caffeine on APAP binding to cytochrome P450 but may be due to an effect of caffeine on the substrate-enzyme complex. The variable effect of caffeine on APAP hepatotoxicity correlated with the effect of caffeine on APAP bioactivation by liver microsomes, regardless of pretreatment. Lack of correlation of aminopyrine N-demethylase, but good correlation of erythromycin N-demethylase activity with the extent of caffeine enhancement of APAP bioactivation following PB or DEX treatment suggests that a murine P450 subfamily similar to the rat P450 3A subfamily may be the candidate in mediating the stimulatory effect of caffeine on APAP bioactivation and APAP-induced hepatotoxicity.

Acetaminophen↗

PubMed1992

Thyroid hormone feedback regulation of the secretion of bioactive thyrotropin in the frog.

Thyrotropin-releasing hormone (TRH), ovine corticotropin-releasing hormone (oCRH) (both 268 nM), and mammalian gonadotropin-releasing hormone (mGnRH) (268 and 2680 nM) stimulated the secretion of bioactive thyrotropin (TSH) by Rana esculenta pituitaries (pars distalis) in vitro. Preincubation of the pituitaries with 50 ng/ml (64 nM) thyroxine (T4) for 6 hr suppressed the TRH- and oCRH-induced (268 nM) secretion of bioactive TSH, but did not affect the response of the pituitaries to 268 nM mGnRH. Triiodothyronine (T3) (64 nM) reduced both the TRH- and mGnRH-stimulated release of bioactive TSH; the response of TSH to TRH even decreased toward basal levels while a significant TSH response to mGnRH remained. In a separate experiment, pituitaries were preincubated for 6 hr with different equimolar doses of T3 and T4 (6.4, 32, and 64 nM); neither treatment affected the mGnRH-stimulated secretion of bioactive TSH. On the other hand, T4 suppressed the TSH response to TRH in a dose-dependent manner. The inhibitory effects of thyroid hormones on the TRH-induced release of bioactive TSH was present for at least 4 hr after their removal from the incubation medium. These results suggest that thyroid hormones exert a negative feedback control on the secretion of bioactive TSH in adult frogs by a direct action on the pars distalis. There may also be differences in thyroid hormone sensitivities of the TSH responses to mGnRH and TRH.

Animals↗

PubMed1992

Behaviour of fetal rat osteoblasts cultured in vitro on bioactive glass and nonreactive glasses.

We examined the behaviour of fetal rat osteoblasts cultured upon bioactive glass and nonreactive glasses, and the supposed stimulatory effects of bioactive glass on osteoblasts. Nonreactive glass cultures showed flattened cells with almost no dorsal ruffles. Bioactive glass cultures showed compact cells with dorsal ruffles and filapodia resulting in the formation of a denser cell layer. For confluent nonreactive glass cultures the osteoblast expression was mainly concentrated in the clustered cells which were formed upon the monolayer, whereas for confluent bioactive glass cultures the osteoblast expression was more generally distributed. The production of type I collagen, osteocalcin and an osteoblast-specific antigen was shown by immunocytochemistry for all cultures, although differences in distribution were observed. The bioactive layer of bioactive glass is responsible for a better osteoblast-like morphology, a higher proliferation rate and generally a better osteoblast expression.

Alkaline Phosphatase↗

PubMed1996

Polymethylmethacrylate composites: disturbed bone formation at the surface of bioactive glass and hydroxyapatite.

The effects of polymethylmethacrylate on bone formation were studied alone and as composites in combination with hydroxyapatite and bioactive glass in the rabbit subchondral femur. Radiographs, histology, computer assisted histomorphometry, scanning electron microscopy and energy dispersive X-ray analysis were used for evaluation. A total of 60 cones were implanted for 3, 6 and 12 weeks. The composite cones consisted of granules of bioactive glass (S56.5P4) or hydroxyapatite embedded in polymethylmethacrylate. Pure polymethylmethacrylate cones served as controls. At the interface of the cones, bone contact was observed only when bioactive glass or hydroxyapatite was present at the cone surface. Fibrous tissue was always found at the polymethylmethacrylate-tissue interface. The osteoconductive bone formation at the surface of bioactive glass and hydroxyapatite was disturbed by polymethylmethacrylate. It seemed to resist bone formation at the interface of both bioactive glass and hydroxyapatite. However, bioactive glass was better able to withstand the detrimental effect of polymethylmethacrylate than hydroxyapatite.

Animals↗

PubMed1992

Testicular Leydig cells in vitro secrete only inhibin alpha-subunits, whereas Leydig cell tumors can secrete bioactive inhibin.

The secretion of inhibin and inhibin-related proteins by testicular Leydig cells was studied by estimation of inhibin immunoreactivity and bioactivity in spent media of preparations of immature and mature rat Leydig cells and of tumor Leydig cells. Immature and mature rat Leydig cells expressed inhibin alpha-subunit mRNA and secreted immunoreactive inhibin. The immunoreactive material did not contain inhibin bioactivity as measured by an in vitro rat pituitary bioassay system. Results of pulse labeling with [35S]methionine followed by immunoprecipitation indicated that the inhibin-related proteins secreted by the immature Leydig cell preparations are 26 kDa and 44 kDa molecules. Mature rat Leydig cells only secreted the 44 kDa inhibin-related protein. Tumor Leydig cells (rat H540 and mouse MA10) secreted immunoreactive and bioactive inhibin, which could be immunoneutralized by an antibody against inhibin. In the culture medium of some H540 tumor Leydig cells 26 kDa and 42 kDa inhibin-related proteins and 30 kDa inhibin were detected. In culture medium of other H540 tumor Leydig cells, not secreting bioactive inhibin, only 26 kDa and 42 kDa inhibin-related proteins were found. No activin bioactivity was detected in culture media of immature rat Leydig cells, H540 and MA10 tumor Leydig cells. It is concluded that normal Leydig cells secrete inhibin alpha-subunits, while Leydig cell tumors can also secrete bioactive inhibin. Neither normal Leydig cells nor Leydig cell tumors produce activin.

Activins↗

PubMed1992

Regulation of inhibin beta B-subunit mRNA expression in rat Sertoli cells: consequences for the production of bioactive and immunoreactive inhibin.

In Sertoli cells from 21-day-old rats, the expression of the mRNA encoding the alpha-subunit of inhibin, and the production of immunoreactive inhibin are stimulated by follicle-stimulating hormone (FSH). In contrast, the amount of beta B-subunit mRNA is not increased after FSH treatment of the cells, and the ratio between bioactive and immunoactive inhibin decreases after stimulation with FSH. These data suggest that the beta B-subunit is the limiting factor in the production of bioactive inhibin. The aim of the present experiments was to investigate the effect of changes in the amount of beta B-subunit mRNA on the production of bioactive and immunoreactive inhibin. During early postnatal testicular development, the relative amounts of the 4.2 kb and 3.5 kb mRNAs encoding the beta B-subunit of inhibin changed markedly. The meaning of this changing ratio between beta B-subunit mRNAs is not clear, since both mRNAs are actively translated, as demonstrated by polysomal analysis. The total amount of beta B-subunit mRNA correlated with the in vitro production of bioactive inhibin as published earlier. Prolonged stimulation of cultured Sertoli cells from 14-day-old rats with 4 beta-phorbol 12-myristate 13-acetate (PMA) caused a decreased expression of the beta B-subunit mRNAs, presumably by down-regulation of protein kinase C. A similar effect was obtained after addition of the calcium ionophore A23187. Concomitantly, a decreased production of bioactive inhibin was observed. Furthermore, Western blotting revealed that secretion of the 32 kDa inhibin alpha beta-dimer was decreased, whereas secretion of the combination of the C-terminal part with the pro-region of the alpha-subunit was increased. It is concluded that the level of the beta B-subunit of inhibin is rate-limiting for the production of bioactive inhibin in cultured Sertoli cells, and that its expression can be influenced by modulation of protein kinase C, and/or intracellular calcium levels.

Alkaloids↗

PubMed1989

Cephalometric changes in Class II, Division 1 cases after orthopedic treatment with the bioactivator.

The bioactivator is an orthopedic appliance that has been used for 20 years in the treatment of Class II, Division 1 cases. The evaluation of its therapeutic effects was performed in this study of 76 9- to 10-year-old patients (at the beginning of treatment). The treated subjects were separated into two groups: group A (bioactivator only) and group B (bioactivator plus headgear). Group C comprised 14 untreated subjects selected as controls. Various statistical assessments were made to separate growth phenomena from treatment effects. It appears that the bioactivator has an effect not only on the dentition but also on the skeletal structures. In both treated groups, the maxillary changes were related to an increased anterior vertical growth and a posterior sagittal growth. The addition of extraoral force helped to achieve a posterior rotation of the upper jaw. When only the bioactivator was worn, the mandibular changes were more vertical than sagittal. The lower jaw appeared more forward, however. When the bioactivator and the headgear force were used simultaneously, the therapeutic effects seemed to be more sagittal than vertical, as if the occipitally directed force vector inhibits or at least exerts a control on the downward growth tendency. Without being significantly different statistically from one to the other, the treated groups showed a marked improvement of the sagittal jaw discrepancy.

Activator Appliances↗

PubMedDate not supplied

Development and characterisation of silver-doped bioactive glass-coated sutures for tissue engineering and wound healing applications.

A novel silver-doped bioactive glass powder (AgBG) was used to coat resorbable Vicryl (polyglactin 910) and non-resorbable Mersilk surgical sutures, thereby imparting bioactive, antimicrobial and bactericidal properties to the sutures. Stable and homogeneous coatings on the surface of the sutures were achieved using an optimised aqueous slurry-dipping technique. Dynamic mechanical analysis (DMA) was used to investigate the viscoelastic parameters of storage modulus and tandelta and thermal transitions of the as-received and composite (coated) sutures. The results generally showed that the bioactive glass coating did not affect the dynamic mechanical and thermal properties of the sutures. The in vitro bioactivity of the sutures was tested by immersion in simulated body fluid (SBF). After only 3 days of immersion in SBF, bonelike hydroxyapatite formed on the coated suture surfaces, indicating their enhanced bioactive behaviour. Resorbable sutures with bioactive coatings as fabricated here, in conjunction with 3-D textile technology, may provide attractive materials for producing 3-D scaffolds with controlled porosities for tissue engineering applications. The bactericidal properties imparted by the Ag-containing glass coating open also new opportunities for use of the composite sutures in wound healing and body wall repair.

Absorbable Implants↗

PubMed2004

Injectable self-curing bioactive acrylic-glass composites charged with specific anti-inflammatory/analgesic agent.

Injectable bioactive acrylic formulations based on poly(methyl methacrylate) (PMMA) and different amounts of bioactive glasses in the system SiO2-CaO-Na2O-P2O5 have been prepared in the presence of the anti-inflammatory analgesic drug fosfosal, the sodium salt of 2-phosphonoxibenzoic acid, to be used in minimally invasive surgery. The injectability of the formulations evaluated according to the established protocol was around 80%. The experimental formulations provided maximum temperatures in the range 50-60 degrees C, which were lower than those of commercial acrylic bone cements currently used in percutaneous vertebroplasty (PVP). Residual monomer content of any formulation was inferior to 5%. Compressive yield strength of dry specimens was in the range 80-95 MPa, but it decreased after immersion in SBF to values in the range 30-50 MPa, due to the dissolution of the bioactive glasses and the drug in the medium. The release of fosfosal was evaluated in vitro (pH = 7.0). The release profile against time obtained from a PMMA cement was quasi-linear and the 80% of the initial amount of drug was released in 175 h. However, for bioactive cements, the 80-100% of the fosfosal charged was released in approximately 48 h, due to the dissolution of the glasses in the medium. Values of weight loss of the cements determined gravimetrically ranged between 16% and 26% depending on the initial amount of fosfosal, i.e. 20 or 30 wt%, respectively. The weight loss and the water uptake were simultaneous processes, and values of hydration degree were around 10-14%. The formation of an apatite-like layer was detected on the surface of the cements at different periods of time depending on the composition of the bioactive glasses. The cements containing the glasses with P2O5 produced the growth of the apatite layer in shorter periods of time. The presence of fosfosal accelerated the precipitation of this layer independently on the glasses. The in vivo biocompatibility studied by intramuscular implantation in rats showed the absence of an anti-inflammatory response and a fibrous layer around the implant for the cement prepared with PMMA/fosfosal which is attributed to the therapeutic action of fosfosal acting in situ. The response to cements prepared with bioactive glasses and fosfosal showed a mild inflammatory reaction with the formation of the typical fibrous capsule around the implanted material.

Analgesics↗

PubMed2005

Bioactivity of titanium following sodium plasma immersion ion implantation and deposition.

Bio-activation of titanium surface by Na plasma immersion ion implantation and deposition (PIII and D) is illustrated by precipitation of calcium phosphate and cell culture. The bioactivity of the plasma-implanted titanium is compared to that of the untreated, Na beam-line implanted and NaOH-treated titanium samples. Our data show that the samples can be classified into two groups: non-bioactive (untreated titanium and beam-line Na implanted titanium) and bioactive (Na-PIII and D and NaOH-treated titanium). None of the four types of surfaces exhibited major cell toxicity as determined by lactate dehydrogenase (LDH) release. However, the LDH release was higher on the more bioactive PIII and NaOH-treated surfaces. From a morphological point of view, cell adherence on the NaOH-treated titanium is the best. On the other hand, the cell activity and protein production were higher on the non-bioactive surfaces. The high alkaline phosphatase activity per cell suggests that the active surfaces support an osteogenic differentiation of the bone marrow cells at the expense of lower proliferation. The use of Na-PIII and D provides an environmentally cleaner technology to improve the bioactivity of Ti compared to conventional wet chemical processes. The technique is also particularly useful for the uniform and conforming treatment of medical implants that typically possess an irregular shape and are difficult to treat by conventional ion beam techniques.

Animals↗

PubMed2005

Protective effect of bioactive fraction of Sphaeranthus indicus Linn. against cyclophosphamide induced suppression of humoral immunity in mice.

The bioactive fraction of Sphaeranthus indicus produced dose dependent increase in humoral immunity and delayed type hypersensitivity (DTH) response as evidenced by increased antibody production and increase in paw edema. The activity at higher doses, however, declines. Humoral antibody (HA) titre lowered by cyclophosphamide (CP) (p < 0.05) was enhanced by bioactive fraction at doses of 200 (p < 0.05) and 400 mg/kg (p < 0.001). There was dose dependent increase in HA titre in normal as well as immunosuppressed animals indicating that drug is effective in humoral immunity. Animals treated with cyclophosphamide and receiving bioactive fraction showed significant change in DTH response, which directly correlates with cell-mediated immunity, as compared to cyclophosphamide alone. Thus, it can be observed that a bioactive fraction of Sphaeranthus indicus acts as potentiator of DTH. Furthermore, the HPTLC fingerprint profile of the bioactive fraction was established to facilitate its identification and characterization. The results suggest that bioactive fraction influences both humoral and cell-mediated immunity and offers protection against immunosuppression induced by the cytotoxic agent cyclophosphamide.

Animals↗

PubMed2006

Interleukin 1 beta is induced by interleukin 11 during decidualization of human endometrial stromal cells, but is not released in a bioactive form.

Blastocyst implantation is dependent on the differentiation of endometrial stromal cells (ESC) into decidual cells. Decidualization of human ESC in vitro is enhanced by interleukin 11 (IL11), with associated changes in gene expression. Genes downstream of IL11 may provide targets for the treatment of implantation failure or the development of non-hormonal contraceptives. This study aimed to examine the effect of IL11 on interleukin 1 beta (IL1B) mRNA and protein expression during in vitro decidualization of ESC. Cells were decidualized with 17beta-estradiol and medroxyprogesterone acetate in the presence or absence of exogenous IL11, and IL1B mRNA was quantified by real-time RT-PCR. Inactive proIL1B and bioactive IL1B in cell lysates and conditioned media were measured using specific immunoassays. Secretion of bioactive IL1B from decidualizing ESC was investigated by in vitro stimulation of decidualizing cells with lipopolysaccharide, interferon gamma or human chorionic gonadotropin. Immunohistochemistry was carried out on cycling and pregnant decidua using an antibody specific for bioactive IL1B. Exogenous IL11 increased by 28-fold the abundance of IL1B mRNA in decidualizing ESC, and total immunoreactive IL1B was also increased. However, this was not reflected in bioactive IL1B secretion from these cells, and none of the tested stimuli were able to induce its release. Bioactive IL1B was detected in vivo at very low levels and at discrete foci in late secretory phase and first trimester decidua. This regulation of latent and bioactive IL1B at the fetal-maternal interface may prime decidual cells to respond rapidly to immunological challenge or to signals from the blastocyst during implantation.

Chorionic Gonadotropin↗

PubMed2000

Differential inhibitory effects of sophoricoside analogs on bioactivity of several cytokines.

Effects of sophoricoside and its analogs on proinflammatory cytokines have been investigated. Sophoricoside, genistein and orobol exhibited inhibitory effects on IL-5, IL-3, GM-CSF and IL-6 bioactivities. Genistin showed inhibitory effects on IL-5 and IL-3 bioactivities, but did not inhibit GM-CSF and IL-6 bioactivities. None of the sophoricoside analogs showed inhibitory effects on both IL-1beta and TNF-alpha bioactivities. Among the compounds, sophoricoside exhibited the highest inhibitory effects on IL-5, IL-3 and IL-6 bioactivities with IC50 values of 1.9 microM, 6.9 microM and 6.0 microM, respectively and orobol did show on GM-CSF bioactivity with an IC50 value of 18.0 microM. The result would provide an additional mechanism by which the compounds exert immunosuppressive and anti-inflammatory effects.

Animals↗

PubMed2002

In vitro evaluation of poly(epsilon-caprolactone-co-DL-lactide)/ bioactive glass composites.

In vitro bioactivity of composites of poly(epsilon-caprolactone-co-DL-lactide) P(CL/DL-LA) containing different amounts (40, 60 and 70 wt%) of bioactive glass, S53P4, was evaluated. Two ranges of granule size of bioactive glass (< 45 microm and 90-315 microm) were blended with P(CL/DL-LA) copolymer in a batch mixer. The composites were characterised by dynamic mechanical thermal analysis. The molecular weight and the melting temperature of the copolymer matrix were adjusted to enable the application of the composite material by injection below 50 degrees C. Formation of Ca-P deposition on the surface of the composites after dissolution in simulated body fluid at 37 degrees C was recorded by scanning electron microscopy. Degradation of the composite material was measured by water absorption and changes in the average molecular weights as a function of the dissolution time. In vitro bioactivity was found to be dependent on the weight fraction and granule size range of the bioactive glass used. The presence of the bioactive filler also accelerated the degradation compared with the neat polymer sample.

Biocompatible Materials↗