Light-weight lead aprons — light on weight, protection or labelling accuracy?

X-ray transmission tests were performed on a Green-Lite (Infab Corporation) apron/vest combination, and compared to a number of other apron/vest combinations routinely used at Christchurch Hospital as well as a sheet of 0.5 mm lead. The materials were X-rayed using the primary beam of a Philips Optimus 50 X-ray machine over an energy range of 50-125 kVp. The entrance and exit doses were recorded and percentage transmission calculated for each kVp. The Green-Lite apron/vest (labelled as 0.5 mm lead at 85 kVp) relies on the overlap at the front to provide the nominal 0.5 mm protection for both the vest and the apron. It performed significantly worse than 0.5 mm of lead and other 0.5 mm lead equivalent apron/vest combinations and provided between 0.3 and 0.39 mm lead equivalent protection depending on the energy used. Vests from other manufacturers all achieved 0.5 mm lead equivalence for a single layer of vest material over the range of energies tested and so were comparable to 1.0 mm lead when doubled. Some aprons relied on a double layer of material to achieve the 0.5 mm lead equivalence (which was not always made clear on the label), while others stated their lead equivalence for a single layer. This resulted in some confusion among wearers of the aprons as to which apron was better.     

Online technology in rural health: supporting students to overcome the tyranny of distance

OBJECTIVE: To determine allied health students' perceptions of the usefulness of online chat as a support mechanism while on fieldwork. DESIGN: Questionnaire. SETTING: Fieldwork predominantly in rural allied health settings. SUBJECTS: Ninety-seven students studying occupational therapy and speech pathology. RESULTS: Students indicated that the major advantage of using online chat while on fieldwork placement was getting peer support (59%), gaining advice (22%) and having contact with the lecturer (15%). The majority of students indicated that they would like to have an online chat room for their next fieldwork placement (72%) and to use online chat when they were practising clinicians (57%). Although 95% of the students attempted to access online chat during their fieldwork placement, only 67% were actually able to participate. Students had difficulty accessing online chat through hospital and community health settings, so instead had to access it via local schools, homes, universities and libraries to use the technology. CONCLUSION: The use of online chat rooms was seen to be beneficial to encouraging peer support while on fieldwork for allied health students.     

Mechanism-based inhibition of cytochrome P450 3A4 by therapeutic drugs

Consistent with its highest abundance in humans, cytochrome P450 (CYP) 3A is responsible for the metabolism of about 60% of currently known drugs. However, this unusual low substrate specificity also makes CYP3A4 susceptible to reversible or irreversible inhibition by a variety of drugs. Mechanism-based inhibition of CYP3A4 is characterised by nicotinamide adenine dinucleotide phosphate hydrogen (NADPH)-, time- and concentration-dependent enzyme inactivation, occurring when some drugs are converted by CYP isoenzymes to reactive metabolites capable of irreversibly binding covalently to CYP3A4. Approaches using in vitro, in silico and in vivo models can be used to study CYP3A4 inactivation by drugs. Human liver microsomes are always used to estimate inactivation kinetic parameters including the concentration required for half-maximal inactivation (K(I)) and the maximal rate of inactivation at saturation (k(inact)).Clinically important mechanism-based CYP3A4 inhibitors include antibacterials (e.g. clarithromycin, erythromycin and isoniazid), anticancer agents (e.g. tamoxifen and irinotecan), anti-HIV agents (e.g. ritonavir and delavirdine), antihypertensives (e.g. dihydralazine, verapamil and diltiazem), sex steroids and their receptor modulators (e.g. gestodene and raloxifene), and several herbal constituents (e.g. bergamottin and glabridin). Drugs inactivating CYP3A4 often possess several common moieties such as a tertiary amine function, furan ring, and acetylene function. It appears that the chemical properties of a drug critical to CYP3A4 inactivation include formation of reactive metabolites by CYP isoenzymes, preponderance of CYP inducers and P-glycoprotein (P-gp) substrate, and occurrence of clinically significant pharmacokinetic interactions with coadministered drugs.Compared with reversible inhibition of CYP3A4, mechanism-based inhibition of CYP3A4 more frequently cause pharmacokinetic-pharmacodynamic drug-drug interactions, as the inactivated CYP3A4 has to be replaced by newly synthesised CYP3A4 protein. The resultant drug interactions may lead to adverse drug effects, including some fatal events. For example, when aforementioned CYP3A4 inhibitors are coadministered with terfenadine, cisapride or astemizole (all CYP3A4 substrates), torsades de pointes (a life-threatening ventricular arrhythmia associated with QT prolongation) may occur.However, predicting drug-drug interactions involving CYP3A4 inactivation is difficult, since the clinical outcomes depend on a number of factors that are associated with drugs and patients. The apparent pharmacokinetic effect of a mechanism-based inhibitor of CYP3A4 would be a function of its K(I), k(inact) and partition ratio and the zero-order synthesis rate of new or replacement enzyme. The inactivators for CYP3A4 can be inducers and P-gp substrates/inhibitors, confounding in vitro-in vivo extrapolation. The clinical significance of CYP3A inhibition for drug safety and efficacy warrants closer understanding of the mechanisms for each inhibitor. Furthermore, such inactivation may be exploited for therapeutic gain in certain circumstances.     

Intra- and extracranial causes alteration in level of consciousness

Acutely ill patients often demonstrate an altered level of consciousness. However, there are a variety of different reasons that may cause this alteration and nurses caring for patients without a defined cerebral event need to be aware of situations that can alter a patient's level of consciousness so that care strategies can be implemented. This article explains the concepts of consciousness and intracranial pressure and what is meant by an 'altered level of consciousness'. Assessment strategies are identified and a simple alternative to the Glasgow Coma Scale is identified that can be used as an initial assessment tool. This then allows the nurse caring for the patient with an altered level of consciousness to rationalize his/her intervention in relation to that patient.     

Somatic symptoms and physiologic responses in generalized anxiety disorder and panic disorder: an ambulatory monitor study

BACKGROUND: Physiologic responses of patients with anxiety disorders to everyday events are poorly understood. OBJECTIVE: To compare self-reports and physiologic recordings in patients with panic disorder (PD), patients with generalized anxiety disorder (GAD), and nonanxious controls during daily activities. DESIGN: Participants underwent four 6-hour recording sessions during daily activities while wearing an ambulatory monitor. Physiologic and subjective data were recorded every 30 minutes and during subject-signaled periods of increased anxiety or tension or panic attack. SETTING: Participants' everyday environment. PARTICIPANTS: Twenty-six patients with PD and 40 with GAD, both without substantial comorbidity, and 24 controls. INTERVENTIONS: Recordings obtained during everyday activities. MAIN OUTCOME MEASURES: Recordings of heart interbeat intervals, skin conductance levels, respirations, motion, and ratings of subjective somatic symptoms and tension or anxiety. RESULTS: Patients with anxiety disorders rated higher on psychic and somatic anxiety symptoms than did controls. Common to both anxiety disorders was diminished autonomic flexibility that manifested itself throughout the day, accompanied by less precise perception of bodily states. The main differences between patients with PD and GAD were a heightened sensitivity to body sensations and more frequent button presses. There also was a trend toward heightened basal arousal in patients with PD, manifesting itself in a faster heart rate throughout the day. CONCLUSIONS: Patients with PD or GAD are more sensitive to bodily changes than nonanxious individuals, and patients with PD are more sensitive than those with GAD. Patients with PD experience more frequent distress than those with GAD and controls, but their physiologic responses are comparable in intensity. The findings suggest that the perception of panic attacks reflects central rather than peripheral responses. The diminished autonomic flexibility observed in both anxiety conditions may result from dysfunctional information processing during heightened anxiety that fails to discriminate between anxiety-related and neutral inputs.     

Progressive increase in incidence and prevalence of multiple sclerosis in Newcastle,Australia: a 35-year study

The prevalence of multiple sclerosis (MS) in Newcastle, Australia increased significantly between 1961 and 1981 and the incidence of the disease also increased between the decades 1950-1959 and 1971-1981. The present study sought to determine whether there has been a further increase in the frequency of MS in the subsequent 15 years, and to examine the potential factors underlying this change. The incidence, prevalence and clinical profile of multiple sclerosis were therefore re-examined in Newcastle, Australia in 1996 using comparable diagnostic criteria and methods to those employed in studies in the same region in 1961 and 1981. There has been a significant progressive increase in prevalence from 19.6 to 59.1 per 100,000 population and a significant increase in incidence from 1.2 to 2.4 per 100,000 population from 1961 to 1996. The most pronounced increase in prevalence was in females and in the age-group over 60 years, and there was also an increased incidence in females aged 20-29 years. There was little change in the age of disease onset, but duration of disease in females had increased substantially. The significant increase in prevalence is attributed to increased incidence, particularly in females; and to increased survival. Although such trends in prevalence have been observed in the Northern Hemisphere, this is the first such study in the Southern Hemisphere to show a longitudinal increase in prevalence and incidence over a period of this duration.     

Should general practitioners purchase health care for their patients? The total purchasing experiment in Britain

Until relatively recently, general practitioners (GPs) have been allowed to work independently, with no requirement to consider the resource implications of their referral and prescribing decisions. In order to align the interests of GPs with the overall objectives of health systems a number of countries have introduced primary care based capitation, funds pooling and budget holding either as experiments or as an overall policy. Are these experiments and policies likely to work? This paper presents evidence from the UK total purchasing experiment, which was the first major quasi-market development in the NHS to be independently evaluated from the outset. Total purchasing gave volunteer groups of practices freedom to purchase all hospital and community health services for their patients. The evidence suggests that whilst GPs have great potential as purchasers, they also have considerable limitations. The expectation that they will be able to improve the quality of patient experience of care, or to alter the use of resources, may not be generally realised. GP-based purchasing may be more appropriate where the task is to alter the balance or location of care between hospital and extramural settings. However, budgetary incentives are not 'magic potions' which have similar effects on behaviour wherever they are introduced. Holding budgets and having independent contracts, while important pre-requisites for being taken seriously in a quasi-market, were not sufficient for effective total purchasing. The paper concludes that health systems should not only value innovation and experimentation and encourage learning from evaluative research; they should also recognise the importance of supportive circumstances for any innovation to effect real and sustained change.     

The ABCs of pedagogy for clinical teachers

BACKGROUND: Clinical teachers rarely receive formal instruction in the basic concepts and principles of education. It is usually assumed that expertise as a practitioner will translate into effectiveness as a teacher. PURPOSE: To identify the important concepts and pedagogic principles, which, if known and understood by clinical practitioners, might enhance their teaching prowess and success. METHOD: We developed a long list of potentially important concepts identified in the education literature. We then conducted a 3-round Delphi expert opinion-soliciting process to identify which of the concepts were of most importance to clinical teachers. RESULTS: Thirteen of the 14 panel members successfully completed the process and achieved 94% reliability in rating the potential importance of the concepts on the e-mailed ratings list. CONCLUSION: We have identified a limited list of core pedagogic concepts, knowledge of which may enhance the success of clinical teachers.     

Sensitivity of water tupelo (Nyssa aquatica) and bald cypress (Taxodium distichum) seedlings to manganese enrichment under water-saturated conditions

In anaerobic soils of wetlands, Mn is highly available to plants because of the decreasing redox potential and pH of flooded soil. When growing adjacent to each another in wetland forests, water tupelo (Nyssa aquatica L.) had 10 times greater leaf manganese concentration than bald cypress (Taxodium distichum [L.] Richard). This interspecific difference was examined over a range of manganese-enriched soil conditions in a greenhouse experiment. Water tupelo and bald cypress seedlings were grown in fertilized potting soil enriched with 0, 40, 80, 160, 240, 320, and 400 mg Mn/L of soil and kept at saturated to slightly flooded conditions. Leaf Mn concentration was greater in water tupelo than bald cypress for all but the highest Mn addition treatment. Growth of water tupelo seedlings was adversely affected in treatments greater than 160 mg Mn/L. Total biomass of water tupelo in the highest Mn treatment was less than 50% of the control. At low levels of added Mn, bald cypress was able to restrict uptake of Mn at the roots with resulting low leaf Mn concentrations. Once that root restriction was exceeded, Mn concentration in bald cypress leaves increased greatly with treatment; that is, the highest treatment was 40 times greater than control (4,603 vs 100 microg/g, respectively), but biomass of bald cypress was unaffected by manganese additions. Bald cypress, a tree that does not naturally accumulate manganese, does so under manganese-enriched conditions and without biomass reduction in contrast to water tupelo, which is severely affected by higher soil Mn concentrations. Thus, bald cypress would be less affected by increased manganese availability in swamps receiving acidic inputs such as acid mine drainage, acid rain, or oxidization of pyritic soils.