In situ randomised trial investigating abrasive effects of two desensitising toothpastes on dentine with acidic challenge prior to brushing

OBJECTIVES

To determine if brushing dentine with 2 moderate RDA desensitising toothpastes, results in a significant dentine wear difference and whether this difference continues to be relevant when preceded with an erosive challenge.

METHODS

An in situ, single centre, single blind, randomised, split mouth study, evaluated the difference in abrasion of 2 toothpastes (SFM - Sensodyne Fresh Mint(®) RDA 70; CPHM - Crest Pro-Health Clean Mint(®) RDA 120) in 28 healthy volunteers. Two toothpaste treatments were administered 3×/day, for each of the two 15 day periods, subjects wearing bi-lateral, lower buccal appliances each with 4 dentine sections. A 2 min extra-oral acidic challenge preceded toothbrushing for 2 study arms. Contact profilometry measured samples at baseline, days 5, 10 and 15.

RESULTS

Brushing with SFM was significantly less abrasive than brushing with CPHM at all time points, with or without a preceding acidic challenge (p<0.0001). The additional dentine loss arising from the erosive challenge prior to brushing with each paste was linear with time and independent of abrasive effect.

CONCLUSIONS

The desensiting toothpastes' RDA, directly related to dentine loss with toothbrushing. An acidic challenge prior to brushing did not negate the benefits of reduced wear from the lower RDA paste compared to the higher RDA paste. When brushing eroded dentine, the additional wear appeared independent of abrasive effect. Dentine hypersensitivity sufferers should be recommended to use a low-moderate RDA toothpaste, not to brush more than 2×/day and not immediately following an acidic challenge.

Randomized in situ clinical study comparing the ability of two new desensitizing toothpaste technologies to occlude patent dentin tubules

OBJECTIVE

To compare the ability of two new desensitizing toothpaste technologies (one a 5% NovaMin-based toothpaste and the other an 8% arginine-based toothpaste) to occlude patent dentin tubules in a clinical environment relative to a negative control of water and a control toothpaste after four days of twice-daily brushing and dietary acidic challenges.

METHODS

The study design was a single-center, single-blind, randomized, split-mouth, four-treatment, two-period, crossover, in situ clinical study. Healthy subjects wore two lower intra-oral appliances, retaining four dentin samples for four treatment days for each period of the clinical study. Samples were brushed twice daily with a test product (days 1-4), with an additional acidic challenge introduced on two selective days. Scanning electron microscopy (SEM) images were taken of the dentin surface, and dentinal tubule occlusion assessed using a categorical scale.

RESULTS

The results demonstrated that the 5% NovaMin toothpaste was statistically superior at occluding patent dentin tubules compared to water (p = 0.009) and the control toothpaste (p = 0.02) at day 4. In contrast, the treatment effect resulting from the 8% arginine toothpaste did not demonstrate the same degree of occlusive propensity, showing no significant difference to the water and control toothpaste at the day 4 time point.

CONCLUSION

Application of the 5% NovaMin toothpaste to dentin showed better dentin tubule occlusion and retention abilities in an oral environment under dietary acid challenge conditions, more so than the 8% arginine toothpaste technology. Given modern dietary habits and practices, these results highlight differences in the acid resistance properties of occlusion technologies, and a potential impact on clinical performance.

Clinical in situ study investigating abrasive effects of two commercially available toothpastes

The aim of this study was to determine if the abrasive effect on dentine of two commercially available toothpastes, known to vary in their in vitro abrasive levels, can be differentiated in an in situ model after 10 days, assessed by contact profilometry. This was a single centre, single blind, randomized, split mouth, two treatment, in situ study, in 34 healthy subjects, evaluating the abrasive effects of two marketed desensitizing toothpastes, (Colgate Sensitive Multi Protection toothpaste - C; Sensodyne Total Protection - S). Subjects wore bi-lateral, lower buccal appliances, each fitted with four dentine sections which were power brushed three times a day with the treatment regimen. Each subject received two toothpaste treatments for 10 days during the treatment period. Samples were measured at baseline and day 10 by contact and non-contact profilometry and day 5 by contact profilometry. Thirty-four subjects were included in the efficacy analysis. Results from contact profilometry showed statistically significant (P < 0.0001) dentine loss compared to baseline at day 5 and 10 for both pastes. At each time point, C showed statistically significantly greater dentine loss than S, P < 0.0001. After 10 days treatment, the difference in dentine loss between the pastes was 1.4 microm. The non-contact profilometry data showed similar trends. After 10 days of treatment, C showed statistically significantly greater dentine loss than S, with treatment difference of 0.9 microm, P = 0.0057. The methodology used has successfully differentiated between the abrasivity of the two pastes in respect of dentine surface loss over time in an in situ environment.

The need for a transparent, ethical, and successful relationship between academic scientists and the pharmaceutical industry: a view of the Group for the Respect of Ethics and Excellence in Science (GREES)

This paper provides recommendations for fair and unbiased relationship between academic scientists and the pharmaceutical industry.

INTRODUCTION

Real or perceived problems in the relationship between academics and the industry have been the subject of much recent debate. It has been suggested that academic clinicians should sever all links with the industry-a view that is rarely challenged.

METHODS

Academic experts and members of the pharmaceutical industry were invited to an expert consensus meeting to debate this topic. This meeting was organized by the Group for the Respect of Ethics and Excellence in Science. Conflict of interest, competing interest, right and duties of academic scientist, authorship, and staff and student education were discussed.

RESULTS

Guidelines for a transparent, ethical, strong, and successful partnership between the academic scientist and the pharmaceutical industry have been provided.

CONCLUSIONS

The Group support interactions between the industry and clinicians provided that it is transparent and ethical.

The composition of hydrogels for cartilage tissue engineering can influence glycosaminoglycan profile

The injectable and hydrophilic nature of hydrogels makes them suitable candidates for cartilage tissue engineering. To date, a wide range of hydrogels have been proposed for articular cartilage regeneration but few studies have quantitatively compared chondrocyte behaviour and extracellular matrix (ECM) synthesis within the hydrogels. Herein we have examined the nature of ECM synthesis by chondrocytes seeded into four hydrogels formed by either temperature change, self-assembly or chemical cross-linking. Bovine articular cartilage chondrocytes were cultured for 14 days in Extracel, Pluronic F127 blended with Type II collagen, Puramatrix and Matrixhyal. The discriminatory and sensitive technique of fluorophore-assisted carbohydrate electrophoresis (FACE) was used to determine the fine detail of the glycosaminoglycans (GAG); hyaluronan and chondroitin sulphate. FACE analysis for chondroitin sulphate and hyaluronan profiles in Puramatrix closely matched that of native cartilage. For each hydrogel, DNA content, viability and morphology were assessed. Total collagen and total sulphated GAG production were measured and normalised to DNA content. Significant differences were found in total collagen synthesis. By day 14, Extracel and Puramatrix had significantly more total collagen than Matrixhyal (1.77+/-0.26 microg and 1.97+/-0.26 microg vs. 0.60+/-0.26 microg; p<0.05). sGAG synthesis occurred in all hydrogels but a significantly higher amount of sGAG was retained within Extracel at days 7 and 14 (p<0.05). In summary, we have shown that the biochemical and biophysical characteristics of each hydrogel directly or indirectly influenced ECM formation. A detailed understanding of the ECM in the development of engineered constructs is an important step in monitoring the success of cartilage regeneration strategies.

Mobile radiography at a music festival

Limb injuries are common at music festival sites and traditionally patients seen by on-site medical services require referral to hospital emergency departments for radiographic exclusion of bony injury. This takes clinical personnel off site, increases demand on local emergency departments and is inconvenient for revellers. This is an audit of the use of a portable digital radiography system at the Virgin music festival in Staffordshire over a 3-year period.

Traumatic extrathoracic lung herniation

We report a case of traumatic extrathoracic lung herniation. This is a rare injury that is potentially life threatening. The imaging features, associated injuries and complications are discussed to facilitate rapid recognition for best patient outcome. Uniquely, we demonstrate the injury with a three-dimensional reconstructed minimum intensity projection.

Adherence to treatment of osteoporosis: a need for study

Adherence to anti-osteoporosis medications is currently low and is associated with poor anti-fracture efficacy. This manuscript reviews the potential design of clinical studies that aim to demonstrate improved adherence, with new chemical entities to be used in the management of osteoporosis.

INTRODUCTION

Several medications have been unequivocally shown to decrease fracture rates in clinical trials. However, in real life settings, long-term persistence and compliance to anti-osteoporosis medication is poor, hence decreasing the clinical benefits for patients.

METHODS

An extensive search of Medline from 1985 to 2006 retrieved all trials including the keywords osteoporosis, compliance, persistence or adherence followed by a critical appraisal of the data obtained through a consensus expert meeting.

RESULTS

The impact of non-adherence on the clinical development of interventions is reviewed, so that clinicians, regulatory agencies and reimbursement agencies might be better informed of the problem, in order to stimulate the necessary research to document adherence.

CONCLUSION

Adherence to therapy is a major problem in the treatment of osteoporosis. Both patients and medication factors are involved. Adherence studies are an important aspect of outcomes studies, but study methodologies are not well developed at the moment and should be improved. Performing adherence studies will be stimulated when registration authorities accept the result of these studies and include the relevant information in Sect. 5.1 of the summary of product characteristics. Reimbursement authorities might also consider such studies as important information for decisions on reimbursement.

Adults with terminal illness: a literature review of their needs and wishes for food

Food refusal can be a source of conflict between dying people and their caregivers. This review examines: the nature and purpose of food; some reasons for and implications of anorexia in terminal illness; ethical principles underpinning responses to declining appetite and food refusal; social transactions between dying people and their caregivers in relation to needs and wishes for food; and the need for further empirical research. The nature and purpose of food in human societies has been studied extensively by anthropologists but the knowledge gained is not often imported into health care practice, where eating is seen from a medical rather than an anthropological perspective. Food refusal may be a consequence of anorexia which is the result of physiological or psychological changes or it may be a deliberate choice in acceptance of impending death. Ethical principles underpinning responses to declining appetite and food refusal have been studied extensively and clear guidance obtained about what would be appropriate behaviour in given circumstances. There is little published empirical work on social transactions between dying people and their caregivers in relation to needs and wishes for food. As the contribution made to effective care-giving by high-quality interpersonal relationships is widely recognized, further knowledge about how best to sustain such relationships in these important circumstances would be useful. Moreover, as such interpersonal relationships often occur in an institutional context, it may be that more can be learnt from close examination of social transactions about how best to structure organizational processes to maximize autonomy and comfort for patients at the end of life. Further research is indicated.

Aorto-left renal vein fistula: is there a place for endovascular management?

PURPOSE

To describe the endovascular treatment of an aorto-left renal vein fistula.

METHODS AND RESULTS

A 77-year-old man with multiple comorbidities presented with low back pain, hematuria, cyanosis, and a pulsatile abdominal mass. Imaging confirmed a 7-cm abdominal aortic aneurysm with a contained rupture into the left renal vein. Owing to the patient's high surgical risk, a Talent Endoluminal Stent-Graft was implanted to satisfactorily exclude the aneurysm. Hemodynamic stability and normal renal function were restored; however, continued perfusion of the sac prompted an attempt to percutaneously repair the renal vein defect. This effort failed, so open laparotomy was necessary.

CONCLUSIONS

Although total endovascular management was not successful in this case, the initial use of a minimally invasive approach allowed the patient's clinical status to improve and lower the risk of subsequent surgery.

The role of physician assistants in the delivery of medical care

Although the physician assistant (PA) profession is slightly more than 30 years old, in its short history, it has had a significant impact on the delivery of quality medical care in the United States. There are approximately 34,000 PAs currently in clinical practice. The purpose of this article is to describe the role physician assistants play in the delivery of medical care and the benefits they bring to the health system and to patients.

Acute airway obstruction during spinal anaesthesia for caesarean section

A 30-year-old primiparous Caucasian woman with known placenta praevia required an emergency caesarean section for a mild antepartum haemorrhage at the onset of spontaneous term labour. Following intravenous prehydration with 500 ml gelatin colloid (Haemaccel trade mark ), spinal anaesthesia was induced in the sitting position with 2.6 ml of 0.5% hyperbaric bupivacaine (13 mg). The patient was then placed in the recumbent position with left lateral tilt, whereupon she suddenly became dyspnoeic. A generalized erythematous urticarial rash with associated facial, periorbital, glossal and perioral oedema became evident. Although maternal blood pressure remained within normal limits, emergency conversion to general anaesthesia with tracheal intubation was necessary to secure the airway. Laryngoscopy revealed gross submucosal, epiglottic and pharyngeal oedema, characteristics of the syndrome of angioneurotic oedema, which may complicate an anaphylactoid reaction. After the airway was secured with a cuffed endotracheal tube, caesarean section proceeded uneventfully and a healthy male infant was delivered. Maternal facial and airway oedema subsided and extubation was performed in intensive care 2 h later. Life-threatening airway obstruction often accompanies angioneurotic oedema. Since parturients have a higher incidence of difficult airway management than the general population, anaphylactoid reactions presenting as angioneurotic oedema pose a particular challenge for the anaesthetist. The lower incidence of allergy associated with hydroxyethyl starch (Hetastarch) may make it a more appropriate choice of colloid in this setting. However, the balance of evidence now suggests that vasopressors, particularly ephedrine, are superior to fluids for maintenance of blood pressure during regional anaesthesia for caesarean section.

Evidence that galactanase A from Pseudomonas fluorescens subspecies cellulosa is a retaining family 53 glycosyl hydrolase in which E161 and E270 are the catalytic residues

A genomic library of Pseudomonas fluorescens subsp. cellulosa DNA was screened for galactanase-positive recombinants. The nine galactanase positive phage isolated contained the same galactanase gene designated galA. The deduced primary structure of the enzyme (galactanase A; GalA) encoded by galA had a Mr of 42 130 and exhibited significant sequence identity with a galactanase from Aspergillus aculeatus, placing GalA in glycosyl hydrolase family 53. The enzyme displayed properties typical of an endo-beta1, 4-galactanase and exhibited no activity against the other plant structural polysaccharides evaluated. Analysis of the stereochemical course of 2,4-dinitrophenyl-beta-galactobioside (2,4-DNPG2) hydrolysis by GalA indicated that the galactanase catalyzes the hydrolysis of glycosidic bonds by a double displacement general acid-base mechanism. Hydrophobic cluster analysis (HCA) suggested that family 53 enzymes are related to the GH-A clan of glycosyl hydrolases, which have an (alpha/beta)8 barrel structure. HCA also predicted that E161 and E270 were the acid-base and nucleophilic residues, respectively. Mutants of GalA in which E161 and E270 had been replaced with alanine residues were essentially inactive against galactan. Against 2,4-DNPG2, E161A exhibited a much lower Km and kcat than native GalA, while E270A was inactive against the substrate. Analysis of the pre-steady-state kinetics of 2,4-DNPG2 hydrolysis by E161A showed that there was an initial rapid release of 2,4-dinitrophenol (2,4-DNP), which then decayed to a slow steady-state rate of product formation. No pre-steady-state burst of 2,4-DNP release was observed with the wild-type enzyme. These data are consistent with the HCA prediction that E161 and E270 are the acid-base and nucleophilic catalytic residues of GalA, respectively.

A survey of knowledge and use of folic acid among women of child-bearing age in Dublin

BACKGROUND

The Medical Research Council vitamin trial highlighted the importance of folic acid in the prevention of neural tube defects. Since 1993, the Irish Department of Health has recommended periconceptional folic acid supplements. The objective of this study was to document the knowledge and behaviour of women in child-bearing years to periconceptional folic acid.

METHODS

A cross-sectional community-based survey was conducted in Dublin using an interviewer administered questionnaire.

RESULTS

A total of 335 women took part in the study, a response rate of 84 per cent. Approximately two-thirds (213/ 335, 63.6 per cent) had heard of folic acid. Knowledge was significantly associated with higher social class and higher education (p < 0.05). Few (18/335, 5.4 per cent), had been advised to take folic acid before pregnancy. Only 9/335 (2.7 per cent) of the women in the study were currently taking folic acid supplements. Three-quarters (75.9 per cent) of the group would be willing to take periconceptional folic acid supplements if they believed it would reduce the risk of malformations. The majority (77.4 per cent) would prefer to take folic acid in tablet form rather than have it added to food.

CONCLUSIONS

This study shows that few women in child-bearing years in Dublin have been advised on folic acid, and very few are taking supplements. However, if advised appropriately the majority would be willing to take periconceptional folic acid in tablet form.

Key residues in subsite F play a critical role in the activity of Pseudomonas fluorescens subspecies cellulosa xylanase A against xylooligosaccharides but not against highly polymeric substrates such as xylan

In a previous study crystals of Pseudomonas fluorescens subspecies cellulosa xylanase A (XYLA) containing xylopentaose revealed that the terminal nonreducing end glycosidic bond of the oligosaccharide was adjacent to the catalytic residues of the enzyme, suggesting that the xylanase may have an exo-mode of action. However, a cluster of conserved residues in the substrate binding cleft indicated the presence of an additional subsite, designated subsite F. Analysis of the biochemical properties of XYLA revealed that the enzyme was a typical endo-beta1,4-xylanase, providing support for the existence of subsite F. The three-dimensional structure of four family 10 xylanases, including XYLA, revealed several highly conserved residues that are on the surface of the active site cleft. To investigate the role of some of these residues, appropriate mutations of XYLA were constructed, and the biochemical properties of the mutated enzymes were evaluated. N182A hydrolyzed xylotetraose to approximately equal molar quantities of xylotriose, xylobiose, and xylose, while native XYLA cleaved the substrate to primarily xylobiose. These data suggest that N182 is located at the C site of the enzyme. N126A and K47A were less active against xylan and aryl-beta-glycosides than native XYLA. The potential roles of Asn-126 and Lys-47 in the function of the catalytic residues are discussed. E43A and N44A, which are located in the F subsite of XYLA, retained full activity against xylan but were significantly less active than the native enzyme against oligosaccharides smaller than xyloseptaose. These data suggest that the primary role of the F subsite of XYLA is to prevent small oligosaccharides from forming nonproductive enzyme-substrate complexes.

Mannanase A from Pseudomonas fluorescens ssp. cellulosa is a retaining glycosyl hydrolase in which E212 and E320 are the putative catalytic residues

Mannanase A (MANA) from Pseudomonas fluorescens, a member of glycosyl hydrolase family 26, was hyperexpressed in Escherichia coli and purified to homogeneity. Analysis of the stereochemical course of mannotetraose hydrolysis by purified MANA showed that the configuration of the anomeric carbon was retained on cleavage of the middle glycosidic bond. These data suggest that the mannanase hydrolyzes mannooligosaccharides by a double-displacement general acid-base mechanism. By hydrophobic cluster analysis (HCA), two glutamate and two aspartate residues were shown to be conserved in all of the glycosyl hydrolase family 26 enzymes analyzed. In addition, HCA suggested that family 26 was related to the GH-A clan (families 1, 2, 5, 10, 30, 35, 39, and 42) of (alpha/beta)8-barrel glycosyl hydrolases, which led to the prediction that E320 and E212 constitute the catalytic nucleophile and acid-base residues, respectively. To investigate the role of these amino acids, site-directed mutagenesis was used to replace the two aspartates with alanine and glutamate, while the two conserved glutamates were changed to alanine and aspartate. The mutant enzymes were purified and their biochemical properties were analyzed. The data showed that neither the D-->A nor the D-->E mutation resulted in a dramatic decrease in enzyme activity, suggesting that the two aspartate residues did not play a pivotal role in catalysis. In contrast, modification of either of the glutamate residues to alanine caused a dramatic decrease in kcat against carob galactomannan, azo-carob galactomannan, mannotetraose and 2,4-dinitrophenyl beta-mannobioside (2,4-DNPM). The E320A mutation did not alter the apparent K(m) (K(m)) of MANA against these substrates, while E212A resulted in a 27-fold decrease in K(m) against 2,4-DNPM. Pre-steady-state kinetics of 2,4-DNPM hydrolysis by E212A showed that there was a rapid burst of 2,4-dinitrophenol release. Circular dichroism and fluorescence spectroscopy indicated that there were no significant differences between the structures of the mutant and wild-type forms of MANA. These data are consistent with E212 and E320 constituting the catalytic acid-base and nucleophile residues of MANA, respectively.

Reversal of parkinsonian symptoms by intrastriatal and systemic manipulations of excitatory amino acid and dopamine transmission in the bilateral 6-OHDA lesioned marmoset

We have investigated the potential of alleviating parkinsonian symptoms by manipulating excitatory amino acid (EAA) transmission, by several different pharmacological means, in a novel primate model of parkinsonism. The model is based on a two-stage bilateral 6-hydroxydopamine lesion procedure in marmosets, which produces a stable but marked parkinsonian condition. Parkinsonian symptoms were reversed in a dose-dependent manner by systemic administration of levodopa and intrastriatal injections of apomorphine administered into either the caudate nucleus or the putamen. (R)-HA-966, a partial agonist for the NMDA receptor associated glycine site, also alleviated parkinsonian symptoms when injected intrastriatally but not when injected systemically. Systemic injection of enadoline, a kappa opiate which blocks release of EAAs, reduced parkinsonian symptoms when injected systemically, though it did not restore completely normal motor behaviour. In contrast, ifenprodil, an antagonist for the NMDA receptor-associated polyamine modulatory site, when injected systemically at an optimal dose, resulted in apparently normal motor behaviour. These data suggest that attenuation of EAA transmission could be used to treat parkinsonism.