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PubMed1989

In vitro bioactivation of phenytoin to a reactive free radical intermediate by prostaglandin synthetase, horseradish peroxidase, and thyroid peroxidase.

Certain toxic effects of phenytoin are thought to result from its cytochrome P-450-catalyzed bioactivation to a reactive arene oxide intermediate that binds covalently to proteins. Using an in vitro system, we examined an alternative hypothesis based upon the cooxidation of phenytoin to a reactive free radical intermediate by prostaglandin synthetase (PGS), horseradish peroxidase, or thyroid peroxidase. Microsomes from hepatic, thyroid, seminal vesicular, or pulmonary tissues, or PGS or horseradish peroxidase, were incubated with the appropriate enzymatic cofactors to study activities of cytochromes P-450 (NADPH), PGS (arachidonic acid), thyroid peroxidase (guiaicol, H2O2), and horseradish peroxidase (H2O2). The production of potentially teratogenic, reactive phenytoin intermediates during in vitro incubations was estimated by the amount of radiolabeled phenytoin bound covalently to microsomal protein or bovine serum albumin and by the detection of a free radical intermediate using ESR spectrometry. Arachidonic acid-dependent bioactivation of phenytoin was demonstrated for purified PGS and ram seminal vesicles (RSV), as well as for liver, lung, and kidney. Optimal arachidonate concentrations varied substantially for different tissues. Arachidonate-dependent binding of phenytoin with PGS and RSV was reduced to baseline levels by coincubation with the cyclooxygenase inhibitor indomethacin. Hydrogen peroxide-dependent covalent binding of phenytoin was observed with thyroid peroxidase and horseradish peroxidase, and binding was significantly reduced in these systems and in PGS and RSV by coincubation with the peroxidase inhibitor methimazole. Glutathione, the antioxidants caffeic acid and butylated hydroxyanisole, and the free radical trapping agent alpha-phenyl-N-t-butylnitrone (PBN) all significantly reduced arachidonate-dependent phenytoin binding. Oxygen uptake was increased in a dose-dependent manner by the arachidonate-dependent bioactivation of phenytoin by PGS. ESR spin-trapping techniques using PBN indicated the generation of a free radical intermediate during the metabolism of phenytoin by PGS. These results suggest that the hydroperoxidase component of PGS, as well as thyroid peroxidase and other peroxidases, can bioactivate phenytoin to a reactive free radical intermediate, which may be toxicologically relevant.

Animals↗

PubMed1989

Bioactivation of the cysteine-S-conjugate and mercapturic acid of tetrafluoroethylene to acylating reactive intermediates in the rat: dependence of activation and deactivation activities on acetyl coenzyme A availability.

The beta-lyase-dependent bioactivation of S-conjugates of tetrafluoroethylene by subcellular fractions from rat liver and rat kidney was studied. Incubation of both hepatic and renal cytosol with S-(1,2,2,2-tetrafluoroethyl)-l-cysteine (TFE-Cys) resulted in the formation of previously unidentified difluorothionamides, indicating difluorothionoacyl fluoride as the main reactive intermediate derived from the beta-lyase-dependent bioactivation of TFE-Cys. The presence of N-difluorothionoacetyl-S-(1,1,2,2-tetrafluoroethyl)-l-cystei ne (TFE-PMS) and difluoroacetic acid in urine of rats treated with N-acetyl-S-(1,1,2,2-tetrafluoroethyl)-l-cysteine (TFE-NAC) points to a similar mechanism of bioactivation in vivo. When TFE-NAC was incubated with 11,000 X g supernatants of rat kidney and liver in the absence of exogenous acetyl coenzyme A (acetyl-CoA), N-deacetylation and subsequent beta-lyase-dependent activation to difluorothionoacyl fluoride could be observed. Both the N-deacetylation of TFE-NAC and the beta-lyase-dependent activation of TFE-Cys were much faster in rat kidney then in rat liver. When TFE-Cys was incubated with 11,000 X g supernatants of rat kidney and rat liver, formation of TFE-NAC could only be observed in the presence of 2 mM exogenous acetyl-CoA; the initial rate of N-acetylation was 5-fold higher in renal then in hepatic fractions. Under these conditions, formation of TFE-PMS was very low. The low urinary excretion of unchanged TFE-NAC (3-5% of dose) upon administration of TFE-NAC points to a high N-deacetylation/N-acetylation ratio in vivo. Due to a very high turn-over of TFE-NAC/TFE-Cys, the availability of the cofactor for N-acetylation, acetyl-CoA, might be rate limiting in the kidney, resulting in accumulation of TFE-Cys followed by increasing beta-lyase-dependent bioactivation of TFE-Cys to reactive intermediates.

Acetyl Coenzyme A↗

PubMed1988

Extracellular matrix production by osteoblasts on bioactive substrata in vitro.

Some bone-substitute biomaterials have been classified as bioactive since they allow direct biological bonding to their surface in vivo. Using in vitro techniques, we have re-created the first stages of this biological bonding phenomenon and compared the initial, fibrillar, extracellular matrices produced by migrated primary osteoblast cell populations in contact with both dense and macroporous calcium phosphate substrata, apatite/bioactive glass composite (ABC) and 45S5 bioactive glass (BAG). The first formed fibrils in contact with these materials may be identified as collagen from their morphology as observed by scanning electron microscopy (SEM). However, the organization of this fibrillar material is significantly different on the five bioactive substrata examined. These in vitro findings may not only be related to both the surface morphology and surface chemistry of the substrata, but also correlated with their levels of in vivo bioactivity.

Animals↗

PubMed1987

Gonadotropin-releasing hormone action upon luteinizing hormone bioactivity in pituitary gland: role of sulfation.

The regulation of rat luteinizing hormone (rLH) bioactivity was studied in an in vitro system using isolated pituitaries from male rats. Stored and released rLH was evaluated in terms of mass (I-LH), bioactivity (B-LH), mobility in nonequilibrium pH gradient electrophoresis, and mannose and sulfate incorporation either in the presence or absence of gonadotropin-releasing hormone (GnRH). GnRH increased the biological potency of stored and released rLH. The pituitary content revealed seven I-LH species (pH 7.2, 7.8, 8.5, 9.0, 9.1, 9.3, and 9.7) and five B-LH species (pH 8.5, 9.0, 9.2, 9.4, and 9.7). The major I-LH and B-LH peaks were at pH 9.0 and 9.2, respectively. I-LH peaks at pH 7.2 and 7.8 are devoid of bioactivity; at these pH values, free rLH subunits are detectable. GnRH increases the amount of both I-LH and B-LH material secreted into the medium, and the major component migrates at pH 8.5 and is probably the alpha beta dimer. [3H]Mannose and [35S]sulfate can be incorporated into stored and released rLH (pH 7.2, 7.8, 9.0, 9.1, and 9.3 and 7.2, 7.8, 8.5, and 9.0, respectively). GnRH decreases [2-3H]mannose incorporation into secreted rLH. [35S]Sulfate was incorporated into I-LH released spontaneously into the medium; the form at pH 7.2 has no biological activity and is probably the free alpha subunit. GnRH decreases the [35S]sulfate-labeled rLH content of the pituitary concomitantly with a 500% increase in [35S]sulfate-labeled released rLH, suggesting that, soon after [35S]sulfate is incorporated, sulfated rLH is released. Sulfatase action on released rLH reveals that sulfation may be related to release of rLH but that sulfate residues are not involved in the expression of rLH bioactivity. In conclusion, GnRH stimulates carbohydrate incorporation and processing of the oligosaccharide residues giving the highest biological potent rLH molecule and also increases sulfation; this step is closely related to the step limiting the appearance of LH in the medium in the absence of GnRH.

Animals↗

PubMed1987

PTH bioactivity in osteoporosis.

The cytochemical bioassay for parathyroid hormone was used to measure the levels of PTH bioactivity in normal elderly subjects and patients suffering from idiopathic or postmenopausal osteoporosis. In normal subjects, PTH bioactivity did not increase with age. In the osteoporotic patients levels of bioPTH discriminated between two populations, one with normal levels and the other with elevated levels. In both these groups the PTH bioactivity was neutralised by the addition of a PTH antiserum. The recovery of the bioactivity of PTH added to the plasma samples was significantly higher in the plasmas from patients with elevated levels of bioPTH. Levels of immunoreactive PTH also discriminated between the two groups of osteoporotic patient although no serum parameters indicative of increased PTH were detectable. However, patients with the high levels of bio- and immunoPTH had a lower incidence of fracture within the previous 12 months.

Adult↗

PubMed1994

Bioactive Arg-Gly-Asp conformations in anti-integrin GPIIb-IIIa antibodies.

Antibodies can mimic the biological function of physiological ligands, yet few examples indicate the structural similarity between antibodies and the ligands that they mimic. Originally, the competition of antibodies for ligand binding sites was conjectured to be through similar three-dimensional conformations, which represent the "internal image" of the given ligand. Here we show that residues in a complementary determining region (CDR) can adopt the same bioactive structures observed in ligands. Structure-function studies of three anti-GPIIb-IIIa murine monoclonal antibodies, PAC-1, LJ-CP3, and OP-G2, indicate that the RYD sequence in their H-CDR3 domain occupies the same conformational space as RGD in conformationally constrained, bioactive, GPIIb-IIIa cell-surface adhesion ligands. The relative location of the guanidinium and carboxylate groups in the RXD regions is identified as an important recognition feature, and the conformational space occupied by this region in the antibodies is only slightly larger than that in the most bioactive peptides. Additionally, we show that antibodies can unveil other potential bioactive sequences, which may impart specificity. Thus antibodies are an exquisite probe for identifying motifs of short adhesion stretches, thereby revealing amino acid sequences and restricted geometries that might be used as lead compounds in drug design.

Amino Acid Sequence↗

PubMed1997

Bioactive glass particles of narrow size range for the treatment of oral bone defects: a 1-24 month experiment with several materials and particle sizes and size ranges.

The aim of this study was to evaluate bone growth around bioactive glass particles in bone defects in comparison to hydroxylapatite particles. The bioactive glass particles were implanted in the partial edentulous jaws of Beagle dogs in two different compositions and several sizes and size ranges. After 1, 2, 3, 6, 12 and 24 months the samples were harvested and processed for undecalcified sectioning. Histological analysis showed a superior response of the bioactive glass particles of composition A and narrow size range (300-355 microns). Besides extensive osteoconductive properties, the bone repair was also stimulated by bone growth in the internally eroded particles. The data demonstrate conclusively that the well known corrosion reactions of the bioactive glass lead to the formation of protective pouches. In these protective pouches formation of new bone is detected without this bone being connected to the bone tissue outside the particles. These islands of newly formed bone tissue function as nuclei for further bone growth and enhance the repair of the defect.

Animals↗

PubMed1997

Investigation of aortic CYP3A bioactivation of nitroglycerin in vivo.

Nitroglycerin (GTN) has been used to treat heart disease for many years. It is generally believed that GTN is a prodrug; however, the mechanism for GTN bioactivation remains unknown. Recent studies, using hepatic microsomes, have suggested the involvement of cytochrome P450 3A (CYP3A) in GTN biotransformation. Here, we used an animal model to test the hypothesis that aortic CYP3A plays a role in the bioactivation of GTN in vivo. Ketoconazole (KCZ), a potent CYP3A inhibitor, was given to rats (50 mg/kg i.p.) 1 hr before a bolus dose of GTN (2 mg/rat i.v.). KCZ decreased GTN-induced cGMP (cyclic guanosine monophosphate) levels by 20 to 30% (P < .05), without affecting basal or S-nitroso, N-acetyl penicillamine-induced levels of cGMP. When rats received dexamethasone (DEX, 30 mg/kg, 4 days i.p.), a strong CYP3A inducer, they exhibited a significant (approximately 50%) higher cGMP response to GTN than the control group. When rats received the combination treatment of both DEX and KCZ, they responded to GTN to the same extent as control rats. Although the effect of KCZ on aortic CYP3A activity cannot be detected (activity in control rats is below the detection limit), KCZ markedly inhibited CYP3A activity in rat livers (2.02 +/- 0.04 vs. 0.31 +/- 0.04 nmol/mg prot/min, P < .05, in control vs. KCZ-treated rats, respectively) and in DEX pretreated rat aorta (0.145 +/- 0.036 vs. 0.042 +/- 0.037 nmol/mg prot/min, P < .05, in rats treated with DEX alone vs. rats treated with both DEX and KCZ, respectively). KCZ did not elicit an effect on aortic glutathione S-transferases, another major metabolic enzyme responsible for GTN biotransformation. DEX enhanced the aortic GST mu activity by 3-fold. However, the activity of GST in aorta did not correlate with the cGMP response to GTN. In conclusion, our results demonstrate that CYP3A activity in aorta is correlated with GTN bioactivation in vivo, but the contribution of this enzyme to overall GTN bioactivation is limited.

Animals↗

PubMed2026

Discovery and characterization of multifunctional bioactive peptides from Alaska Pollock (Gadus chalcogrammus) milt: hybrid in silico, in vitro, and proteomic approaches.

The growing demand for multifunctional bioactive peptides has sparked interest in underutilized marine by-products as sustainable bioresources. This study explored Alaska Pollock (Gadus chalcogrammus) milt protein as a novel source of peptides with anti-inflammatory, anti-hypertensive, and anti-diabetic effects. Protein composition was analyzed via LC-MS, followed by in silico digestion and bioactivity prediction. Molecular docking identified peptides targeting DPP-IV, α-glucosidase, ACE, GLP-1 receptor, COX-2, MuRF1, and the 20S proteasome. Among the candidates, a promising peptide (CLPPH) was synthesized and validated in vitro, demonstrating inhibitory effects on nitric oxide production, DPP-IV, ACE, and α-glucosidase. These results highlight CLPPH's potential as a multifunctional bioactive peptide and support the valorization of Alaska Pollock milt as a sustainable source for functional foods and nutraceutical applications.

Animals↗

PubMed2026

Bioactive peptides for meat quality and preservation: Integrating peptidomics and computational screening.

Bioactive peptides generated from meat proteins, fermented meat products, and slaughter by-products have attracted increasing attention as functional molecules for improving meat quality and preservation. In meat systems, peptides can be produced through endogenous postmortem proteolysis, microbial fermentation, gastrointestinal digestion, or controlled enzymatic hydrolysis of underutilized animal by-products. These peptides are closely associated with key meat science endpoints, including postmortem tenderization, oxidative stability, color retention, flavor development, microbial inhibition, and the valorization of processing by-products. However, although high-resolution peptidomics has greatly expanded the identification of meat-derived peptide sequences, their translation into practical meat applications remains limited by matrix interactions, processing stability, sensory constraints, safety concerns, and insufficient validation in real meat systems. This review synthesizes recent advances in meat-related peptidomics and computational screening, including sequence-based prediction, machine learning, molecular docking, molecular dynamics, stability assessment, and safety-oriented filtering. Particular attention is given to how these approaches can prioritize peptides with antioxidant, antimicrobial, flavor-modulating, and preservation-related functions under meat-specific technological constraints. By integrating peptide generation pathways, mass spectrometry-based identification, in silico prioritization, and meat quality endpoints, this review proposes a stage-gated framework for translating meat-derived bioactive peptides from discovery to application. Future research should strengthen matrix-specific validation, standardized peptidomic reporting, and safety assessment to support the use of bioactive peptides in meat quality improvement, clean-label preservation, and circular utilization of meat industry by-products.

Animals↗

PubMed1997

Scanning electron microscopy of the bone-bioactive implant interface.

Rods of three bioactive materials, apatite/wollastonite glass ceramic (AW-GC), bioactive glass (BG), and dense slip-cast hydroxyapatite (HA), were implanted in the femora of 23 Wistar rats for periods of 1-4 weeks. The samples were harvested following vascular perfusion fixation and the femora freeze-fractured for scanning electron microscopy to expose the bone/implant interface. The focus of our observations was when new bone was forming on the implant surfaces irrespective of the implantation period. Scanning microscopy of the hydroxyapatite rods demonstrated that in areas where bone bonding had occurred, the implant surface was composed of globular accretions which fused to form a cement-like matrix to which collagen fibers were attached. Dissolution of individual grains of the implant surface created a roughened surface topography. Such features were not found in the transcortical portions of these implants. Similar globular accretions were also found on the surface of bulk AW-GC, although bone apposition was not disrupted by the critical point-drying procedure, and thus the interface was more difficult to image. Nevertheless, the collagen of the bony compartment interdigitated with an interfacial layer which was morphologically similar to that found on HA. The most surface reactive material, BG, demonstrated an interfacial structure where the surface reactive calcium phosphate layer was clearly distinguished from the underlying bulk implant material. However, this layer was separated from the overlying collagen-containing bony compartment by a second, thinner, calcified layer which corresponded to the cement line matrix into which the collagen fibers were inserted. Our results show that the new bone interface formed with these three bioactive materials is morphologically comparable to that of cement lines found naturally in bone-remodeling sites, and that this interfacial layer is formed on the chemically active surface of the biomaterial. The degree to which the cement line matrix interdigitated with the implant was a product of the reactivity of the implant surface.

Animals↗

PubMed1997

Behavior of fetal rat chondrocytes cultured on a bioactive glass-ceramic.

We examined the behavior of fetal rat chondrocytes cultured on a bioactive glass-ceramic containing apatite and wollastonite (A.W.G.C.). Biomaterial surface topography and profiles were evaluated by bidimensional profilometry and revealed a rough surface for the glass-ceramic compared to the plastic coverslips used as controls. Chondrocyte attachment was evaluated by measuring the number of attached cells after one day of culture and by morphological observations. Chondrocytes attached in great numbers to the material surface by means of focal contacts containing vinculin and beta1-integrin. Fluorescent labeling of actin and vimentin revealed a poor spreading of chondrocytes on the bioactive glass-ceramic compared to the plastic coverslips, where the cells appeared to adhere intimately to the surface and exhibited polygonal arrays of stress fibers. During the following days of culture, chondrocytes proliferated, colonized the surface of the material, and, finally, on day 10, formed nodular structures composed of round cells separated by a dense extracellular matrix. Furthermore, these clusters of round cells were positive for type II collagen and chondroitin sulfate, both hard markers of the chondrocyte phenotype. In addition, protein synthesis, alkaline phosphatase activity, and proteoglycan production were found to increase gradually during the culture period with a pattern similar to that observed on control cultures. These results demonstrate that the bioactive glass-ceramic tested in this study appears to be a suitable substrate for in vitro chondrocyte attachment, differentiation, and matrix production.

Actins↗

PubMed1998

Release of bioactive human growth hormone from a biodegradable material: poly(epsilon-caprolactone).

We have characterized the biodegradable material poly(epsilon-caprolactone) (PCL) as a delivery system for recombinant human growth hormone (hGH). Two contrasting methods for the manufacture of the biomaterial were investigated: namely, solvent casting and solvent casting particulate leaching; the latter yielded porous PCL discs. The degree of porosity, which was assessed by scanning electron microscopy, could be controlled by incorporating selected concentrations of particulate sodium chloride during the manufacturing process. Bioactive hGH released from the PCL preparations was quantified with a highly sensitive and precise bioassay which was based upon hGH activation of rat lymphoma Nb2 cells. Eluates obtained from control discs of PCL which had not been loaded with hGH proved to be nontoxic when tested on these cells. The release of bioactive hGH from hormone-loaded nonporous discs of PCL was found to be a direct function of the initial hormone loading dose. Increased porosity of the discs manufactured by solvent casting particulate leaching increased the delivery of hGH from discs which had been immersion loaded. However, hGH release after surface loading was independent of porosity. Hormone concentrations were also assessed by immunoassay so that the ratios of bio- to immunoactivity (B:I ratio) of the hormone release could be determined. We found that the B:I ratio of the hormone after release from unstored discs was identical to that of the hormone prior to its incorporation into the PCL, demonstrating that the mild incorporation procedures utilized had not adversely affected the structural integrity of the hormone. However, if the hormone-loaded discs were stored at 37 degrees C prior to elution, the B:I ratios of the hGH released decreased indicating that this compromised the bioactive site.

Animals↗

PubMed1998

Effect of bioactive glass particle size on osseous regeneration of cancellous defects.

The bioactive glass known as Bioglass or Perioglass (USB) (US Biomaterials, Alachua, FL) has proven to be an effective graft material owing to the apatite layer which forms on the surface of the glass, promoting bone formation. USB particles range in size from 90 to 710 microns in diameter, as determined by optical microscopy. A similar bioactive material, BioGran (OV) (Orthovita, Malvern, PA), was developed to limit the particle size of 4555 to the range between 300 and 360 microns, as determined by sieving. The objective of this study was to histologically and biomechanically compare the 4555 bioactive glass, produced by US Biomaterials, in a wide particle range (USB) to the narrower particle range glass produced by Orthovita (OV) The grafted defects will then be compared to normal cancellous bone (NORM) of the distal femur in rabbits. Histologically, more bone was quantified at both 4 and 12 weeks within the defects filled with USB and NORM when compared to the limbs filled with OV (p < 0.05). The OV particles had greater particle axes and larger particle areas on average than the USB particles (p < 0.05). However, the particle axis and area of the two materials decreased with time at a similar rate. Biomechanically, the USB- and OV-grafted defects had comparable peak compressive load, compressive stiffness, and compressive modulus which were equivalent to normal bone.

Animals↗

PubMed1998

Bone bonding in bioactive glass ceramics combined with bone matrix gelatin.

To determine how to encourage inductive osteogenesis on bioactive ceramics and accelerate the bonding of implants to the surrounding bone, we studied the role of autolyzed antigen-extracted allogeneic bone gelatin (AAAG) in bone bonding to bioactive ceramic implants in rabbit tibiae. Smooth-surfaced plates (15 x 10 x 2 mm) of apatite and wollastonite containing glass-ceramic were implanted into the proximal metaphyses of tibiae, with AAAG packed into the medullary cavity in one limb but not in the contralateral limb, which served as a paired control. After 2, 4, 8, 16, and 25 weeks, bone bonding and bone formation at the bone/implant interfaces were evaluated by a detaching test and undecalcified histological examination. The tensile failure load increased from 2 to 25 weeks for both groups. The failure load of the AAAG-treated group was significantly greater than that of the control group at every stage. Histologically, the AAAG-treated specimens showed active new bone formation in the medullary cavity and extensive bonding between the implant and bone at early periods. The percentage of bony covering in the AAAG-treated group was significantly higher than that of the controls at all intervals except at 25 weeks. The results of this study suggest that the addition of osteoinductive AAAG to a bioactive implant may significantly accelerate bone apposition to the implant and improve the bonding process at the interface, which would help to establish an earlier and stronger bonding between the implants and the surrounding bone.

Animals↗

PubMed1998

Influence of sol and surface properties on in vitro bioactivity of sol-gel-derived TiO2 and TiO2-SiO2 films deposited by dip-coating method.

Different sol-gel-derived titania and titania-silica films were prepared and their properties related to in vitro bioactivity. The films were prepared by depositing the sols on the substrate surface using a dip-coating method. The sols were monitored carefully as a function of time, using rheological techniques and dynamic light scattering. The topography of the films was characterized using atomic force microscopy, and thicknesses and refractive indexes of the films were evaluated by fitting transmittance spectra measured in a wave length region of 370-1100 nm with a spectrophotometer. The in vitro bioactivity tests were performed in simulated body fluid. Surface topography was found to be of great importance with respect to the bioactivity of the studied films.

Biocompatible Materials↗

PubMed1998

Effect of polymerization reaction inhibitor on mechanical properties and surface reactivity of bioactive bone cement.

We introduced an inhibitor to the polymerization reaction of bioactive bone cement (AWC) consisting of MgO-CaO-SiO2-P2O5-CaF2 apatite and wollastonite containing glass-ceramic powder and bisphenol-alpha-glycidyl methacrylate based resin, together with an increased amount of accelerator but without any prolongation of its setting time in order to improve the degree of polymerization and decrease the amount of incompletely polymerized monomers on the cement surface. A comparison was made between the AWC containing the inhibitor [AWC(I+)] and the AWC without it [AWC(I-)] with regard to setting parameters, mechanical properties, and surface reactivity in vitro and in vivo. The proportion of glass-ceramic powder added to the AWC was 70% (w/w). The total amount of heat generation and the peak temperature of the AWC(I+) during polymerization were slightly greater than those of the AWC(I-). The mechanical strength of AWC(I+) was higher than that of the AWC(I-) under wet conditions. In simulated body fluid, the width of the Ca-P rich layer on the surface of the AWC(I+) was less than that on the AWC(I-) after 28 days of immersion, although the rate of apatite formation on the top surface of the AWC(I+) was almost identical to that on the AWC(I-) surface. Histological examination using rat tibiae up to 26 weeks revealed that the bioactivity of the AWC(I+) was equivalent to that of the AWC(I-). Scanning electron microscopy and energy-dispersive X-ray microanalysis demonstrated that the Ca-P rich layer in the AWC(I+) was significantly narrower than that in the AWC(I-) at the same time points. These results indicate that introduction of the inhibitor improved the mechanical properties of the AWC and made the Ca-P rich layer narrower, but it had no adverse effect on bioactivity.

Animals↗

PubMed1999

Interactions between the bioactive glass S53P4 and the atrophic rhinitis-associated microorganism klebsiella ozaenae.

In an aqueous environment, ions are released from a bioactive glass (BAG) and the pH rises in its vicinity. This may influence both growth and colonization of microorganisms. We studied the effects of the BAG S53P4 on the atrophic rhinitis-associated microorganism Klebsiella ozaenae. The glass was used in the form of granules or discs. Growth inhibition was studied using an agar plate test. Adhesion was studied by incubating bacterial suspension with the glass. The effect of the presence of the bacteria on the formation of the Si-rich layer on the bioactive glass was also analyzed. Furthermore, a follow up study of 19-74 months with ozena patients surgically treated with the BAG S53P4 was performed. The bioactive glass showed no clear growth inhibition of K. ozaenae in the agar plate test. K. ozaenae showed low adherence to the BAG S53P4. No growth of the microbe was seen on the glass during the 8 h incubations and the Si-rich layer was formed normally. The clinical follow-up study showed no infections of the implants and the symptoms of the patients were markedly reduced. Thus, the BAG S53P4 did not favor adhesion and colonization of K. ozaenae, in vitro, which is supported by the in vivo findings showing no BAG-associated infections or reinfections.

Adolescent↗