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Biomedical subjects

G Wright

Publications and source records attributed to G Wright.

At least 37 records · Page 2Linked to original sources
PubMed2002

Intra-muscular ketorolac administered as a supplemental analgesic for removal of impacted third molar teeth: a prospective study.

BACKGROUND: Post-operative pain follows dentalveolar oral surgery. Ketorolac is a potent non-steroidal analgesic with moderate anti-inflammatory effects. The purpose of this study was to test whether a single supplementary dose of ketorolac reduced post-operative pain experienced by patients having third molar teeth removed. METHODS: A prospective double-blind trial utilizing 30mg of ketorolac and a standard anaesthetic and surgical technique was performed on 65 female patients having impacted third molar teeth removed. Assessment was made by means of a patient questionnaire and visual analogue pain scales and subjected to statistical analysis. RESULTS: There was a statistically significant difference confirming improved pain relief for patients receiving ketorolac 30mg at the early postoperative stage (two hours) but at later time intervals (four and six hours) there was no significant difference. Seventy two per cent of patients found ketorolac to be a satisfactory analgesic for postoperative pain. There were minimal side effects. CONCLUSION: A single supplemental dose of ketorolac 30mg provides improved pain relief in the immediate post-operative phase following the removal of third molar teeth. Oral ketorolac can be recommended as a oral analgesic for post-operative pain, with minimal side effects.

Adolescent↗
PubMed2001

Elevated calcium in preneoplastic cells activates NF-kappa B and confers resistance to apoptosis.

Early preneoplastic cells (sup+) exhibit increased susceptibility to apoptosis, which is lost in late stage preneoplastic cells (sup-). Sup+ cells, which undergo apoptosis when cultured in low serum, show little or no DNA binding activity to nuclear factor (NF)-kappa B either in 10% or 0.2% serum. In contrast sup- cells, which are resistant to apoptosis in low serum, show a sustained constitutive activation of NF-kappa B. The constitutive activation of NF-kappa B observed in sup- cells is not due to loss of I kappa B alpha. We considered that the activation of NF-kappa B in sup- cells might be secondary to an increase in cytosolic Ca(2+), since sup- cells have a cytosolic Ca(2+) level that is double that in sup+ cells. In support of a role for Ca(2+), lowering cytosolic Ca(2+) in sup- cells by addition of the cell-permeable Ca(2+) chelator 1,2 bis(O-aminophenoxy)ethane-N, N, N', N'-tetraacetic acid-acetoxymethyl ester (BAPTA-AM) reduced cytosolic Ca(2+) by approximately 31% relative to untreated sup- cells, concomitant with a 65% reduction in NF-kappa B DNA binding activity and a reduction in I kappa B kinase (IKK) activity. In sup- cells in low serum, addition of BAPTA-AM also resulted in a significant ( approximately 50%) increase in caspase-3 activity. Raising extracellular Ca(2+) in sup+ cells resulted in a slight activation of I kappa B kinase and in enhanced NF-kappa B DNA binding activity. Using proteasome and calpain inhibitors, we determined that the basal activity of NF-kappa B in sup- cells is largely proteasome-independent, but sensitive to calpain inhibitors. Taken together these data suggest that the elevated Ca(2+) in sup- cells causes a modest activation of IKK, which likely contributes to the enhanced basal activation of NF-kappa B in sup- cells; however, the predominant effect of Ca(2+) appears to be mediated by Ca(2+)-enhanced degradation by calpain.

Animals↗
PubMed2001

Oxidative stress inhibits the mitochondrial import of preproteins and leads to their degradation.

The mitochondrion depends upon the import of cytosolically synthesized preproteins for most of the proteins that comprise its structural elements and metabolic pathways. Here we have examined the influence of redox conditions on mitochondrial preprotein import and processing by mammalian mitochondria. Paraquat pretreatment of isolated mitochondria inhibited the subsequent import preornithine transcarbamylase (pOTC) in vitro. In intact cells oxidizing conditions led to decreased levels of mature OTC and accumulation of its preprotein. Implicating a mitochondrial import lesion, the fluorescence of pOTC-GFP (a protein in which the presequence of pOTC was fused to green fluorescent protein) transfected cells was decreased by paraquat treatment while cytosolic wild-type GFP remained largely unaffected. The accumulation of preproteins was enhanced by proteasome inhibitors. We observed that precursor proteins that failed to be imported, due to oxidizing conditions or an intrinsically slower import rate, are susceptible to degradation. Inhibition of the proteasome was also found to lead to higher levels of the translocase outer membrane protein 20 (Tom20) and to the perinuclear accumulation of mitochondria. These studies indicate that cellular redox conditions influence mitochondrial import, which, in turn, affects mitochondrial protein levels. A role for the proteasome in this process and in general mitochondrial function was also indicated.

Acetylcysteine↗
PubMed2001

Positive regulatory domain I binding factor 1 silences class II transactivator expression in multiple myeloma cells.

The major histocompatibility complex (MHC) class II transactivator (CIITA) acts as a master switch to activate expression of the genes required for MHC-II antigen presentation. During B-cell to plasma cell differentiation, MHC-II expression is actively silenced, but the mechanism has been unknown. In plasma cell tumors such as multiple myeloma the repression of MHC-II is associated with the loss of CIITA. We have identified that positive regulatory domain I binding factor 1 (PRDI-BF1), a transcriptional repressor, inhibits CIITA expression in multiple myeloma cell lines. Repression of CIITA depends on the DNA binding activity of PRDI-BF1 and its specific binding site in the CIITA promoter. Deletion of a histone deacetylase recruitment domain in PRDI-BF1 does not inhibit repression of CIITA nor does blocking histone deacetylase activity. This is in contrast to PRDI-BF1 repression of the c-myc promoter. Repression of CIITA requires either the N-terminal acidic and conserved PR motif or the proline-rich domain. PRDI-BF1 has been shown to be a key regulator of B-cell and macrophage differentiation. These findings now indicate that PRDI-BF1 has at least two mechanisms of repression whose function is dependent on the nature of the target promoter. Importantly, PRDI-BF1 is defined as the key molecule in silencing CIITA and thus MHC-II in multiple myeloma cells.

Genes, MHC Class II↗
PubMed2001

Differences in expert and lay judgments of risk: myth or reality?

This article evaluates the nine empirical studies that have been conducted on expert versus lay judgments of risk. Contrary to received wisdom, this study finds that there is little empirical evidence for the propositions (1) that experts judge risk differently from members of the public or (2) that experts are more veridical in their risk assessments. Methodological weaknesses in the early research are documented, and it is shown that the results of more recent studies are confounded by social and demographic factors that have been found to correlate with judgments of risk. Using a task-analysis taxonomy, a template is provided for the documentation of future studies of expert-lay differences/similarities that will facilitate analytic comparison.

Journal Article↗
PubMed2001

Establishing river basin organisations inVietnam: Red River, Dong Nai River and Lower Mekong Delta.

River basin management is receiving considerable attention at present. Part of the debate, now occurring worldwide, concerns the nature of the organisations that are required to manage river basins successfully, and whether special-purpose river basin organisations (RBOs) are always necessary and in what circumstance they are likely to (i) add to the management of the water resources and (ii) be successful. The development of river basin management requires a number of important elements to be developed to a point where the river basin can be managed successfully. These include the relevant laws, the public and non-government institutions, the technical capabilities of the people, the understanding and motivation of people, and the technical capacity and systems, including information. A river basin organisation (or RBO) is taken to mean a special-purpose organisation charged with some part of the management of the water resources of a particular river basin. Generally speaking, such organisations are responsible for various functions related to the supply, distribution, protection and allocation of water, and their boundaries follow the watershed of the river in question. However, the same functions can be carried out by various organisations, which are not configured on the geographical boundaries of a river basin. This paper outlines recent work on river basin organisation in Vietnam, and makes some comparisons with the situation in Australia.

Conservation of Natural Resources↗
PubMed2000

Clinical trial (GUSTO-1 and INJECT) evidence of earlier death for men than women after acute myocardial infarction.

Epidemiologic studies of acute myocardial infarction (AMI) have described gender differences in the time of death after infarction, with greater numbers of men dying before hospitalization than women. However, in controlled, hospital-based clinical trials, women die at higher rates than men. We hypothesized that evidence of a gender difference in the time of death following AMI may be found in controlled studies of hospitalized AMI patients. We performed a retrospective analysis of the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-1) and International Joint Efficacy Comparison of Thrombolytics (INJECT) trial databases using logistic regression modeling and time-to-death analyses. The age-adjusted female-to-male odds ratio for mortality was 1.4 (95% confidence interval 1.3 to 1.5) in GUSTO-1 and 1.5 (95% confidence interval 1.3 to 1.8) in INJECT. GUSTO-1 showed that among patients dying during the first 24 hours after symptom onset, men died an average of 1.7 hours earlier than women (p<0.001). This difference was due to earlier deaths among men < or =65 years of age. Furthermore, in GUSTO-1, the analysis of time to death in hour increments demonstrated that greater proportions of men died at earlier time points than women and a disproportionate number of early deaths occurred among younger men than among women of any age or older men. In INJECT, where time to death could only be analyzed in 1-day increments, no gender differences were evident. These results raise the possibility that the pattern of earlier death for men in thrombolytic clinical trials represents the continuation of a gender-specific mortality pattern that began before hospitalization. The death of a disproportionate number of men before hospitalization may represent an inherent gender bias for clinical studies enrolling only hospitalized patients. More high-risk men would be excluded from these studies than women because of death before hospitalization. Hence, gender comparisons of in-hospital mortality rates may artificially inflate values for women.

Clinical Trials as Topic↗
PubMed2000

Adaptation of dental plaque to metabolise maltitol compared with other sweeteners.

UNLABELLED: There is some evidence that plaque can adapt to regular exposure to some bulk sweeteners, leading to increased metabolism and acidogenic potential of the sweetener. This potential for adaptation varies between non-sugar sweeteners and has important implications for manufacturers of food, confectionery and medicines used long-term. Maltitol (99% purity crystalline D-maltitol) is a relatively newly approved non-sugar sweetener and appears to have potentially good dental properties. OBJECTIVES: To compare plaque adaptation to pure sucrose, sorbitol, xylitol or maltitol and the effect of their prolonged use on acid production by plaque from sucrose, in vivo. METHODS: Two series of plaque pH experiments were carried out. Each experiment involved a 14 day adaptive period when four 5 g lozenges of the sweetener were taken between meals each day. Each experiment was separated by a 14 day wash-out period. Acid production was quantified as: (a) minimum pH; and (b) cH area (difference between plaque pH curve and resting value, expressed as cH units). RESULTS: Thirteen adults, of mean age 41 years completed the study. When adaptation of dental plaque to the metabolism of sweeteners was compared, there was a statistically significant difference (p = 0.033) between xylitol and sorbitol, and between xylitol and sucrose but not between xylitol and maltitol. When the effect of prolonged use of sweeteners on acid production after sucrose rinsing was compared, there were no statistically significant differences between the sweeteners. CONCLUSION: Dental plaque does not adapt to metabolise xylitol or maltitol following prolonged exposure over 14 days.

Adaptation, Physiological↗
PubMed2000

Materials and techniques for electrochemical biosensor design and construction.

New developments in biosensor design are appearing at a high rate as these devices play increasingly important roles in daily life. This review aims to highlight recent developments in materials and techniques for electrochemical biosensor design and construction. Rapid growth in biomaterials, especially the availability and application of a vast range of polymers and copolymers associated with new sensing techniques have led to remarkable innovation in the design and construction of biosensors, significant improvements in sensor function and the emergence of new types of biosensor. Nevertheless, in vivo applications remain limited by functional deterioration due to surface fouling by biological components. However, new copolymers based upon biomembrane mimicry have been extensively investigated during the last two decades, raising hopes that the problems related to interactions between foreign surfaces and biological fluids and tissues may soon be solved.

Biocompatible Materials↗
PubMed2000

Glucose sensor with improved haemocompatibilty.

A new biocompatible copolymer has been synthesised and used in an electrochemical enzyme-based glucose sensor. The copolymer incorporates three segments including a monomer with an electrically neutral phosphorylcholine head group that is able to reject protein adsorption and two segments that increase the affinity to polyurethane substrate. Peel and solution circulation tests showed that this material has high attachment to polyurethane. With the new copolymer as the outermost layer and the polyurethane as the diffusion-limiting membrane, the sensor showed extended linearity up to 50 mM glucose and stable output in bovine serum for 70 h. During in vivo tests, the sensor exhibited a steady current signal and a rapid transient response when the glucose concentration was raised. These results imply that the haemocompatibility of the glucose sensor coated with the new copolymer has been improved, which is crucial for a sensor used for clinical real-time monitoring. The material may also be suitable for application to other implantable devices.

Animals↗
PubMed2000

Blastocyst transfer: a useful tool for reduction of high-order multiple gestations in a human assisted reproduction program.

OBJECTIVE: We evaluated the efficacy of blastocyst transfer in decreasing the incidence of high-order multiple gestations after in vitro fertilization. STUDY DESIGN: We conducted a retrospective analysis of 218 patients who were undergoing in vitro fertilization and by our criteria of three 8-cell embryos on day 3 could receive either a day 3 transfer of cleaved embryos or a day 5 transfer of blastocysts. Ongoing pregnancy rates, implantation rates (determined by the total number of visualized gestational sacs), and multiple pregnancy rates were compared between the 2 groups. RESULTS: Respective day 3 and day 5 ongoing pregnancy rates (61% and 51%) and implantation rates (35% and 33%) were not significantly different. There were 9 triplet or higher gestations in the day 3 group and 0 in the day 5 group. CONCLUSION: Blastocyst transfer can be used to reduce the number of embryos transferred and the resultant incidence of high-order multiple pregnancies while maintaining high pregnancy rates.

Adult↗
PubMed2000

Risk perception in the U.K. oil and gas production industry: are expert loss-prevention managers' perceptions different from those of members of the public?

This article investigates potential differences in risk perception between experts (loss-prevention managers in the U.K. oil and gas production industry) and nonexperts (managers and students). Extant research on expert versus nonexpert perceptions of risk is reviewed, followed by the present study concerning risk perceptions of seven pen-picture scenarios involving the occurrence of hazardous events in the U.K. oil and gas production industry. In contrast to many of the earlier studies of expert versus nonexpert perceptions of risk, the present analysis concludes that experts did not judge the overall riskiness of the portrayed hazardous events as less risky than the nonexperts. Nevertheless, the experts believe more strongly than our nonexperts that the risks portrayed in the scenarios pose little threat to future generations, are more precisely known, and are relatively controllable. Use of multiple regression analysis to help uncover the basis of overall riskiness assessments for expert and lay respondents was inconclusive, however. Finally, little evidence was found that nonexperts were any more heterogeneous in their risk perceptions than experts. It may be that the nature of the risks assessed in the present study may account for the general lack of clear expert versus nonexpert differences in overall perceptions of the riskiness of hazardous events in the North Sea. Earlier findings of strong expert versus nonexpert differences in risk perception assessed hazards of major public concern. It is inferred that using such extreme hazards may have resulted in an exaggerated view of differences in expert versus public (nonexpert) perception of risk.

Journal Article↗