PubMed Health⌕ Search

Biomedical subjects

J E Gough

Publications and source records attributed to J E Gough.

At least 19 recordsLinked to original sources
PubMed2004

Osteoblast responses to tape-cast and sintered bioactive glass ceramics.

The advantage of tape-cast bioactive glasses lies in the manufacturing procedure, which allows the build-up of layers and, therefore, the production of complex shapes. This, therefore, has applications to tissue engineering, where specific shapes are required such as repair of craniofacial defects. The bioactivity of tape-cast discs sintered at temperatures ranging from 800 degrees C to 1000 degrees C and for 3 or 6 h was analyzed by FTIR. Tape-cast discs were used to culture primary human osteoblasts, and cell attachment, cell death, collagen production, nodule formation, and mineralization were studied. These responses were dependent upon Si and Na release profiles of the tape-cast discs, and development of the hydroxyapatite layer.

Apoptosis↗
PubMed2004

Controlled degradation and macrophage responses of a fluoride-treated polycaprolactone.

We have developed a new bone replacement material based on polycaprolactone (PCL), which can act as a suitable matrix for monomer transfer molding of degradable composites. A boron trifluoride catalyst with glycerol additive was used to produce PCL with a degradation rate that can be altered by treatment with fluoride ions. The effect of cations on the degradation of the polymer and macrophage cell responses are discussed. We found that treatment with fluoride ions reduced the degradation rate. No significant difference between these three fluorides was observed although a general trend was seen where KF-treated PCL appeared to degrade slower than NaF-treated PCL which was slower than NH(4)F-treated PCL. Variation in solubilities of the salts was observed where the K(+) cation had the highest solubility and the Na(+) cation had the lowest solubility, which suggests that NaF was able to degrade the polymer more efficiently than the other fluorides. No significant macrophage activation was observed after culture on the polymer surfaces as determined by peroxide and IL-1 beta release, whereas some activation occurred after culture in degradation products.

Animals↗
PubMed2004

Osteoblast attachment and mineralized nodule formation on rough and smooth 45S5 bioactive glass monoliths.

Human primary osteoblast responses to smooth and roughened bioactive glass of 45S5 (Bioglass trade mark ) composition (46.1% SiO(2), 26.9% CaO, 2.6% P(2)O(5), 24.4% Na(2)O) were analysed in vitro. The smooth and rough surfaces had R(a) values and peak to valley distances of 0.04, 4.397, 2.027, and 21.328 microm, respectively. Cell attachment and morphology was observed using phalloidin staining of the actin cytoskeleton and revealed significant differences between smooth and rough surfaces. Cells that were spiky in appearance on the rough compared to the smooth surface formed an organized actin matrix much later on the rough surface. Scanning electron microscopy revealed many cell filipodia extending from more rounded cell bodies on the rough surface. A significantly greater number of nodules on the rough surface was observed, and these were shown to mineralize when supplemented with beta-glycerophosphate and dexamethasone. Raman spectroscopy confirmed the presence of hydroxyapatite in the mineralized cultures showing a definite peak at 964 cm(-1). FTIR analysis showed hydroxyapatite formation occurred more rapidly on the rough surface. This study demonstrates that although initial cell morphology was less advanced on the roughened surface, the cells were able to form mineralized nodules in greater numbers. This may have implications to bone tissue engineering using bioactive glasses.

Biocompatible Materials↗
PubMed2003

In vitro evaluation of novel bioactive composites based on Bioglass-filled polylactide foams for bone tissue engineering scaffolds.

Highly porous poly(DL-lactic acid) (PDLLA) foams and Bioglass-filled PDLLA composite foams were characterized and evaluated in vitro as bone tissue engineering scaffolds. The hypothesis was that the combination of PDLLA with Bioglass in a porous structure would result in a bioresorbable and bioactive composite, capable of supporting osteoblast adhesion, spreading and viability. Composite and unfilled foams were incubated in simulated body fluid (SBF) at 37 degrees C to study the in vitro degradation of the polymer and to detect hydroxyapatite (HA) formation, which is a measure of the materials' in vitro bioactivity. HA was detected on all the composite samples after incubation in SBF for just 3 days. After 28 days immersion the foams filled with 40 wt % Bioglass developed a continuous layer of HA. The formation of HA for the 5 wt % Bioglass-filled foams was localized to the Bioglass particles. Cell culture studies using a commercially available (ECACC) human osteosarcoma cell line (MG-63) were conducted to assess the biocompatibility of the foams and cell attachment to the porous substrates. The osteoblast cell infiltration study showed that the cells were able to migrate through the porous network and colonize the deeper regions within the foam, indicating that the composition of the foams and the pore structures are able to support osteoblast attachment, spreading, and viability. Rapid formation of HA on the composites and the attachment of MG-63 cells within the porous network of the composite foams confirms the high in vitro bioactivity and biocompatibility of these materials and their potential to be used as scaffolds in bone tissue engineering and repair.

Biocompatible Materials↗
PubMed2003

In vitro bioactivity of S520 glass fibers and initial assessment of osteoblast attachment.

Bioactive glass fibers are attractive materials for use as tissue-engineering scaffolds and as the reinforcing phase for resorbable bioactive composites. The bioactivity of S520 glass fibers (52.0 mol % SiO(2), 20.9 Na(2)O, 7.1 K(2)O, 18.0 CaO, and 2.0 P(2)O(5)) was evaluated in two media, simulated body fluid (SBF) and Dulbecco's modified Eagle's medium (DMEM), for up to 20 days at 37 degrees C. Hydroxyapatite formation was observed on S520 fiber surfaces after 5 h in SBF. After a 20-day immersion, a continuous hydroxyapatite layer was present on the surface of samples immersed in SBF as well as on those samples immersed in DMEM [fiber surface area to solution volume ratio (SA:V) of 0.10 cm(2)/mL]. Backscattered electron imaging and EDS analysis revealed that the hydroxyapatite layer formation was more extensive for samples immersed in SBF. Decreasing the SA:V ratio to 0.05 cm(2)/mL decreased the time required to form a continuous hydroxyapatite surface layer. ICP was used to reveal Si, Ca, and P release profiles in DMEM after the 1st h (15.1, 83.8, and 29.7 ppm, respectively) were similar to those concentrations previously determined to stimulate gene expression in osteoblasts in vitro (16.5, 83.3, and 30.4 ppm, respectively). The tensile strength of the 20-microm diameter fibers was 925 +/- 424 MPa. Primary human osteoblast attachment to the fiber surface was studied by using SEM, and mineralization was studied by using alizarin red staining. Osteoblast dorsal ruffles, cell projections, and lamellipodia were observed, and by 7 days, cells had proliferated to form monolayer areas as shown by SEM. At 14 days, nodule formation was observed, and these nodules stained positive for alizarin red, demonstrating Ca deposition and, therefore mineralization.

Bone Substitutes↗
PubMed2003

Long-term craniofacial osteoblast culture on a sodium phosphate and a calcium/sodium phosphate glass.

The aim of this study was to determine the characteristics of human craniofacial osteoblasts cultured on sodium phosphate glass and calcium-sodium phosphate glass in a long-term culture of up to 28 days. The characteristics studied were attachment, proliferation, alkaline phosphatase activity, collagen-1 production, and mineralization. A comparison of the degradation rate, measured by mass loss of the glasses, which are intended for use as a component of a novel degradable composite for craniofacial bone repair, was also performed. It was our hypothesis that the glass would be degradable with a change in degradation rate observed by calcium addition and support osteoblast proliferation and expression of the above characteristics. The inclusion of calcium into the reaction mixture significantly decreased the degradation rate, and it is suggested that the slower degradation is the result of pseudo crosslinking (ionic crosslinks rather than covalent bonding) of the polyphosphate chains by the calcium ions. Therefore, twice as many P-O bonds will need to be hydrolyzed for dissolution of the metal phosphate to occur, therefore greatly reducing the rate of hydrolysis. Osteoblasts were able to attach, spread, and proliferate in a manner comparable with the positive control, as shown by analysis of variance. Formation of a collagen-rich mineralized matrix was also observed. The results presented here suggest that a biocompatible soluble glass has been produced, which has potential to be included in a novel biodegradable craniofacial implant.

Calcium↗
PubMed2003

Craniofacial osteoblast responses to polycaprolactone produced using a novel boron polymerisation technique and potassium fluoride post-treatment.

There is no ideal material for craniofacial bone repair at present. The aim of this study was to test the biocompatibility of polycaprolactone (PCL) synthesised by a novel method allowing control of molecular weight and degradation rate, with regard to it being used as matrix for a biodegradable composite for craniofacial bone repair. Human primary craniofacial cells were used, isolated from paediatric skull after surgery. Cell responses were analysed using various assays and antibody staining. Cells attached and spread on the PCL in a similar manner to the Thermanox controls as shown by phalloidin staining of F-actin. Cells maintained the osteoblast phenotype as demonstrated by alkaline phosphatase assay and antibody staining throughout the time points studied, up to 28 days. Cells proliferated on the PCL as shown by a DNA assay. Collagen-1 staining showed extensive production of a collagen-1 containing extracellular matrix, which was also shown to be mineralised by alizarin red staining. Short-term (up to 48 h) attachment studies and long-term (up to 28 days) expression of markers of the osteoblast phenotype have been demonstrated on the PCL. This new method of synthesising PCL shows biocompatibility characteristics that give it potential to be used for craniofacial bone repair.

Absorbable Implants↗
PubMed2003

Scaffolds and biomaterials for tissue engineering: a review of clinical applications.

Tissue engineering is a multidisciplinary area of research aimed at regeneration of tissues and restoration of organ function. This is achieved through implantation of cells/tissues grown outside the body or by stimulating cells to grow into an implanted matrix. In this short review, we discuss the use of biomaterials, in the form of scaffolds, for tissue engineering and review clinical applications to otorhinolaryngology-head and neck surgery.

Biocompatible Materials↗
PubMed2002

Synthesis, degradation, and in vitro cell responses of sodium phosphate glasses for craniofacial bone repair.

This report outlines the initial synthesis, degradation, and short-term biocompatibility of sodium phosphate glasses, for use in the drawing of fibers and manufacture of biodegradable composites. Biocompatibility studies were performed using a macrophage cell line and primary human craniofacial osteoblasts. Sodium hydrogen phosphate and sodium dihydrogen phosphate glass synthesized for less than 1 h, resulted in a higher degradation rate than glass synthesized for 3 h or more (0.015 mg cm(-2) h(-1)). Glasses with high and low ratios of hydrogen phosphate to dihydrogen phosphate had very similar degradation rates. A condensation route for the formation of the glass should give rise to varying degradation rates with varying ratios of starting materials. It is suggested that the degradation rate of the glass is independent of the concentrations of the initial reagents and that ring-opening polymerization, which reaches an equilibrium state, occurs. Biocompatibility studies suggest minimal macrophage activation (low levels of peroxide and interleukin-1beta release and rounded morphology) and high osteoblast biocompatibility. The ultimate aim of our studies is to produce a biocompatible soluble phosphate glass that can be drawn into fibers for incorporation into a polycaprolactone matrix for craniofacial bone repair. This report demonstrates the successful production of a soluble glass, which is biocompatible with regard to osteoblasts and macrophages. Recent data from our laboratory have demonstrated successful fiber drawing and production of a novel polycaprolactone.

Absorbable Implants↗
PubMed2002

Novel bioresorbable and bioactive composites based on bioactive glass and polylactide foams for bone tissue engineering.

Bioresorbable and bioactive tissue engineering scaffolds based on bioactive glass (45S5 Bioglass(R)) particles and macroporous poly(DL-lactide) (PDLLA) foams were fabricated. A slurry dipping technique in conjunction with pretreatment in ethanol was used to achieve reproducible and well adhering bioactive glass coatings of uniform thickness on the internal and external surfaces of the foams. In vitro studies in simulated body fluid (SBF) demonstrated rapid hydroxyapatite (HA) formation on the surface of the composites, indicating their bioactivity. For comparison, composite foams containing Bioglass(R) particles as filler for the polymer matrix (in concentration of up to 40 wt %) were prepared by freeze-drying, enabling homogenous glass particle distribution in the polymer matrix. The formation of HA on the composite surfaces after immersion in phosphate buffer saline (PBS) was investigated to confirm the bioactivity of the composites. Human osteoblasts (HOBs) were seeded onto as-fabricated PDLLA foams and onto PDLLA foams coated with Bioglass(R) particles to determine early cell attachment and spreading. Cells were observed to attach and spread on all surfaces after the first 90 min in culture. The results of this study indicate that the fabricated composite materials have potential as scaffolds for guided bone regeneration.

Journal Article↗
PubMed2001

Osteoblast cell death on methacrylate polymers involves apoptosis.

The success of an implant depends on the implant-tissue interface. There are many causes of implant failure, one of which is tissue necrosis. The aim of this in vitro study was to determine whether cell death of primary human osteoblasts (implant site specific cells) occurred by apoptosis (a form of programmed cell death) on two methacrylate polymers. Cells were cultured on poly(ethyl methacrylate)/tetrahydrofurfuryl methacrylate and poly(methyl methacrylate in the form of 13-mm discs, in conditioned medium containing leachable monomer and in the presence of various concentrations of monomer itself in the culture medium. It was found that monomer and leached monomer caused apoptosis of human osteoblast cells in this system. Tetrahydrofurfuryl methacrylate monomer was found to be more toxic than currently used monomer methylmethacrylate. Preincubation of polymers in serum containing medium was found to increase the biocompatibility of the polymers. High levels of apoptosis occurred on polymer used directly after polymerization. Apoptosis levels were decreased after polymer was incubated at 60 degrees C overnight or for 3 days. Apoptosis therefore may occur in cells at the implant site in vivo.

Apoptosis↗
PubMed2001

Exertional rhabdomyolysis in a body builder abusing anabolic androgenic steroids.

Rhabdomyolysis, or acute skeletal muscle destruction, may be accompanied by myoglobinaemia, myoglobinuria, and an elevated serum creatine kinase level. This disorder has many potential causes. In this article, the authors describe a case of rhabdomyolysis occurring after vigorous weight lifting by a man who was supplementing his weight-training programme with the intake of anabolic androgenic steroids dispensed to him by a colleague.

Adult↗
PubMed2001

Are emergency department patients at risk for herb-drug interactions?

OBJECTIVES: To determine the prevalence of herbal and/or dietary supplement use and identify patients at risk for herb-drug interactions. METHODS: A convenience sample of 944 patients were surveyed to determine the prevalence and types of supplements used. Patients with heart disease, diabetes, psychiatric disorders, and/or hypertension were assessed for potential interactions. RESULTS: One hundred thirty-five (14.3%) patients reported regular use. Of these, 79.3% were taking supplements concurrently with prescription medications, and 80.0% were administered medication(s) in the emergency department. Cardiac: 19.8% (n = 33) reported regular use, with four potential interactions. Hypertension: 20.3% (n = 54) reported regular use, with two potential interactions. Diabetes: 15.9% (n = 20) reported regular use, with no known interactions. Psychiatric: 15.9% (n = 10) reported regular use, with one potential interaction. CONCLUSIONS: Six patients were identified at risk for seven known herb-drug interactions. The prevalence of undisclosed herbal supplement use and lack of research on these supplements suggest that more patients may be at risk.

Adult↗
PubMed2000

Complications of a retrograde intubation in a trauma patient.

The authors report the case of an elder woman involved in a motor vehicle collision (MVC) requiring emergent intubation using the technique of retrograde intubation (RI). Since RI is a blind technique, potential complications arising from its use are numerous and may result in increased morbidity and mortality. Such was the case of this RI that involved incorrect placement of the endotracheal tube (ETT), resulting in suboptimal ventilation and increased morbidity. Additionally, this case illustrates how the failure to detect this error in multiple settings (ambulance, helicopter, emergency department) led to unnecessary and potentially deleterious procedures and significant delay in providing the basics of trauma care, oxygenation and ventilation. Although theoretical complications of RI have been addressed in the past, there have been very few published reports of actual complications. The emergency physician must be aware of difficult airways, options available to establish alternative airways, and methods to confirm appropriate placement of the ETT. The authors also discuss the indications, procedures, and complications involved in performing an RI.

Accidents, Traffic↗
PubMed1998

Can quantitative capnometry differentiate between cardiac and obstructive causes of respiratory distress?

STUDY OBJECTIVE: To determine whether quantitative measurement of end-tidal carbon dioxide (ETCO2) can differentiate between cardiac and obstructive causes of respiratory distress. DESIGN: Prospective observational study. SETTING: Emergency department (ED) of a tertiary care hospital. PATIENTS: Adult patients who presented to the ED with moderate-to-severe dyspnea. Patients were excluded if they were unable to cooperate with the performance of peak expiratory flow rate (PEFR) or ETCO2 tests, were younger than 18 years of age, or had received prehospital intervention for their respiratory distress. INTERVENTIONS: Physicians obtained an ETCO2 level and PEFR prior to ED pharmacologic intervention. A hand-held capnometer with digital read-out was used to obtain the ETCO2 level. The patient's age, sex, initial vital signs, breath sounds and medication history, the presence or absence of diaphoresis and/or orthopnea, the duration of symptoms, the chest radiograph interpretation, and final diagnosis were also recorded. MEASUREMENTS AND RESULTS: Forty-two patients were eligible for inclusion in the analysis. The mean ETCO2 level was 31.1+/-9.4 mm Hg; the mean PEFR was 161.3+/-53.1 L/min. The ETCO2 levels for pulmonary edema/congestive heart failure (CHF) patients differed significantly from those of asthma/COPD patients (27.1+/-7.8 mm Hg vs 33.4+/-9.6 mm Hg; p=0.0375). However, no single ETCO2 level was found to be a reliable predictor of diagnosis. CONCLUSION: ETCO2 levels for pulmonary edema/CHF patients differ significantly from those of asthma/COPD patients. However, no single ETCO2 level reliably differentiates between the two disease processes.

Adult↗
PubMed1997

Assessment of breath sounds during ambulance transport.

STUDY OBJECTIVE: To determine whether the environment of a moving ambulance affects the ability of our-of-hospital care providers to auscultate breath sounds. METHODS: Out-of-hospital care providers assessed breath sounds with a previously described breath-sounds model in a quiet environment (control) and in a moving ambulance. The setting was a nonurban emergency medical services system and an interhospital transport agency based at a 600-plus-bed tertiary care center. The participants were physicians, transport nurses, and advanced life support EMS providers routinely involved in the emergency out-of-hospital treatment and transportation of the ill and injured. The accuracy with which participants identified the presence or absence of breath sounds in the two environments was compared with the use of the chi 2 test, with the alpha-value set at .05. RESULTS: The accuracy of breath-sounds assessment in the control environment was 96% (251 of 260); the sensitivity was 96% and the specificity 97%. The accuracy of breath-sounds assessment in the experimental environment was 54% (140 of 260); the sensitivity was .09% and the specificity 98%. Participants were significantly less likely to hear breath sounds in the moving ambulance than in the quiet room (P < .001). CONCLUSION: Assessment of breath sounds is hampered by the environment of a moving ambulance.

Ambulances↗
PubMed1997

Do pulse checks cause a significant delay in the initial defibrillation sequence?

This study was undertaken to determine if checking for a pulse between initial defibrillations causes a clinically significant delay in the administration of the defibrillations. Ten emergency department nurses and 10 emergency medicine resident physicians were timed delivering three successive defibrillations (200, 300 and 360 J) to a manikin under three randomly assigned scenarios: (1) without pulse checks; (2) with pulse checks performed by an assistant; and (3) with pulse checks performed by the participant. All participants performed the three defibrillation scenarios using three different models of defibrillators. Repeated measures analysis of variance was used to compare mean defibrillation times for the three scenarios. The mean time was 20.4 +/- 1.0 s for defibrillation without pulse checks; 20.2 +/- 1.2 s with pulse checks by an assistant and 22.0 +/- 2.0 s with pulse checks by the participant. There was a statistically significant difference between no pulse checks and pulse checks by the participant. No statistically significant difference was noted between no pulse checks and pulse checks by an assistant. We conclude that checking for a pulse does cause a statistically significant delay in the administration of defibrillations. This difference, however, is not likely to be clinically relevant.

Analysis of Variance↗