Dentists' restorative decision‐making and implications for an ‘amalgamless’ profession. Part 1: a review

The Minamata Convention has agreed to a worldwide reduction and ultimate elimination in the production and use of mercury containing products. This will have implications for the practice of dentistry. Australian organizations' pronouncements on the issue are limited and research examining the Australian context dated. The restoration of teeth with direct materials has changed significantly since the 1980s. Up to this time amalgam was the material of choice for direct posterior restorations. Its properties and guidelines for placement were, and remain, well established. Resin composite has replaced amalgam as the material of choice in many clinical situations. Despite inherent clinical disadvantages compared to amalgam, there continues to be a shift toward greater use of resin composite. There is consensus worldwide that the restoration of posterior teeth using resin composite now exceeds that of amalgam. The reasons for this are reviewed in this article along with current evidence and commentary relating to direct restorative and evidence‐based decision‐making, minimally invasive approaches, and approaches to education. The implications for these in an ‘amalgamless’ profession are identified.     

A review of drugs that contribute to bleeding risk in general dental practice

The risk of postoperative bleeding is a daily concern for many general dental practitioners. A thorough medical and medication history must be taken to consider all risk factors, particularly drugs, that contribute to bleeding risk. While the risk from drugs such as aspirin, warfarin and clopidogrel are well known, the extent to which new antiplatelet agents and direct oral anticoagulants affect bleeding risk is less well understood. In addition, there are drugs other than antithrombotics, such as antidepressants and complementary medicines that also impair haemostasis. The aim of this paper is to provide dentists with an updated overview of the drugs commonly encountered in general dental practice that can contribute to a patient’s postoperative bleeding risk.     

Status epilepticus in children: aetiology, treatment, and outcome

This retrospective study includes 65 children treated for status epilepticus at Tampere University Hospital in Finland. Aetiology of the condition, effectiveness of the treatment protocol, including short barbiturate anaesthesia to prevent prolonged status epilepticus episodes, and neurological outcome were evaluated. Symptomatic aetiology was present in 40% of status epilepticus episodes, and 37% of episodes were induced by fever. Neurological sequelae secondary to status epilepticus were identified in 15% of the cases and subsequent epilepsy in 23% during the mean follow-up time of 3.6 years. There were no status epilepticus-related deaths. The cut-off point of status epilepticus duration for significant risk for permanent neurological sequelae was 2 hours. Our treatment protocol, including short barbiturate anaesthesia in refractory cases, was able to abort status epilepticus in less than 2 hours in 75% of cases. We conclude that early and prompt use of barbiturate anaesthesia should be encouraged, and may explain our low morbidity figures.     

HUMAN CYTOCHROME P450 ENZYMES EXPRESSED IN BACTERIA: REAGENTS TO PROBE MOLECULAR INTERACTIONS IN TOXICOLOGY

1. Phase I metabolism of drugs is accomplished by the concerted actions of a limited number of cytochrome P450 enzymes with wide but often overlapping substrate specificities. Although metabolism generally accelerates the clearance of drugs, reactive products may also be generated that cause toxic effects. 2. Because individuals vary in the range and levels of different P450 forms, it is useful to be able to determine the specific isoforms involved in a particular metabolic reaction, in order to estimate the extent of variation within a population in the pharmacokinetics of specific drugs. Such studies may also allow predictions to be made regarding the relative susceptibility of different individuals to possible adverse effects associated with drug treatment. 3. Human cytochrome P450 enzymes are now routinely expressed as recombinant proteins in many different systems, including mammalian cell culture, yeast, baculovirus and Escherichia coli. The latter system is particularly useful when large amounts of protein are required for biophysical studies, but can also be adapted to routine examination of pathways of drug metabolism and toxicology. 4. The present review provides an analysis of strategies used for enhancing cytochrome P450 expression in bacteria and for examining the activity of the recombinant proteins. The potential applications of recombinant P450 are discussed, with particular emphasis on investigation of the roles of cytochrome P450 forms in the metabolism and the toxicity of drugs.     

Activation of resting T lymphocytes by a monoclonal antibody directed against an allotypic determinant on the T cell receptor

The murine monoclonal antibody F23.1 reacts with an allotypic determinant on the beta chain of the T cell receptor expressed by approximately 20% of T helper and cytotoxic T lymphocytes of most common mouse strains. This IgG2a antibody, either in soluble form or covalently coupled to Sepharose beads, can activate resting T cells from naive animals to proliferate. Interestingly, under all conditions of activation, the antibody can only induce proliferation if exogenous lymphokines in the form of Con A supernatant are provided. Thus, it is unlike most lectins and anti-T3 antibodies in this regard. Furthermore, under all conditions of culture, F23.1 activates preferentially the Lyt-2+ subset of T cells. This is the case even in the presence of accessory cells. Further evidence is provided that two soluble lymphokines, different from IL2, are required to initiate IL2-dependent growth and to allow the expression of lytic activity.     

Genetic difference in HLA-DR phenotypes between coeliac disease and transitory gluten intolerance

Genetic differences in HLA phenotypes were studied in coeliac disease to investigate why some patients do not react with mucosal damage after gluten challenge. Forty five children with coeliac disease and 16 with transitory gluten intolerance were typed; 76 subjects served as controls. HLA phenotypes in children with coeliac disease had significantly higher proportions of DR3/X and DR5/7 than controls (48.8% v 11.8% and 26.7% v 5.3%). Children with transitory gluten intolerance had lower DR3/X (43.8%) than children with coeliac disease and there were no DR5/7 phenotypes. Further analysis of similarly well defined cases might show whether genetic differences in the DR3/X and DR5/7 phenotypes can serve as a marker for the permanence of gluten intolerance.     

Reforming tuberculosis control in Ukraine: results of pilot projects and implications for the national scale-up of DOTS

The period of economic transition has had severe consequencesfor health and health systems in Ukraine. The tuberculosis (TB)situation illustrates this. The strategy recommended by theWorld Health Organization (WHO) for TB, directly observed treatmentshort-course (DOTS), has the potential to provide real improvementsin TB services, forming the basis of the response to the growingepidemic. In 2002, Ukraine, financially supported by USAID andthe European Community (EC), began to introduce DOTS throughpilot projects in Mariupol and Kyiv City. The aim of this studyis to assess the feasibility, effectiveness, health servicecost, patient cost, and the cost-effectiveness of these pilots,in order to inform the national scale-up of DOTS. The study finds that DOTS is feasible and has the potentialto be both effective and cost-effective in Ukraine. Followingthis study, Ukraine adopted DOTS as a national TB control strategyin 2005. However, the pilots also found that there are severalevidence-related concerns and perverse economic incentives toboth providers and patients that will need to be addressed ifnational scale-up is to be successful. These include concernsrelated to the treatment of MDR-TB, economic benefits to somepatients to remain hospitalized, and payments to providers andhealth facilities that support current practices. These willneed to be addressed if Ukraine is to develop an effective responseto its emerging TB epidemic.     

Bone marrow patterns in aplastic anemia: observations with 1.5-T MR imaging

Six patients diagnosed as having aplastic anemia underwent magnetic resonance (MR) imaging. The bone marrow in the lumbar spine, pelvis, and proximal femora was examined in each case. One patient had a normal marrow signal intensity (SI) and pattern and was considered cured of disease. The other patients had varying numbers of focal low-SI areas interspersed with high-SI areas in the marrow of the spine. The pelves and proximal femora of all patients had diffuse high-SI marrow without focal abnormalities. Biopsy of a lumbar vertebral body in one patient demonstrated that the focal low-SI areas may have been islands of active hematopoietic cells scattered in otherwise fatty marrow. MR may prove to be a valuable, noninvasive method of following the response of patients with aplastic anemia to therapy; more investigation is necessary before this can be definitely concluded.