Free-atom-like d states in single-atom alloy catalysts.

Alloying provides a means by which to tune a metal catalyst's electronic structure and thus tailor its performance; however, mean-field behaviour in metals imposes limits. To access unprecedented catalytic behaviour, materials must exhibit emergent properties that are not simply interpolations of the constituent components' properties. Here we show an emergent electronic structure in single-atom alloys, whereby weak wavefunction mixing between minority and majority elements results in a free-atom-like electronic structure on the minority element. This unusual electronic structure alters the minority element's adsorption properties such that the bonding with adsorbates resembles the bonding in molecular metal complexes. We demonstrate this phenomenon with AgCu alloys, dilute in Cu, where the Cu d states are nearly unperturbed from their free-atom state. In situ electron spectroscopy demonstrates that this unusual electronic structure persists in reaction conditions and exhibits a 0.1 eV smaller activation barrier than bulk Cu in methanol reforming. Theory predicts that several other dilute alloys exhibit this phenomenon, which offers a design approach that may lead to alloys with unprecedented catalytic properties.

The electronic structure of iridium oxide electrodes active in water splitting.

Iridium oxide based electrodes are among the most promising candidates for electrocatalyzing the oxygen evolution reaction, making it imperative to understand their chemical/electronic structure. However, the complexity of iridium oxide's electronic structure makes it particularly difficult to experimentally determine the chemical state of the active surface species. To achieve an accurate understanding of the electronic structure of iridium oxide surfaces, we have combined synchrotron-based X-ray photoemission and absorption spectroscopies with ab initio calculations. Our investigation reveals a pre-edge feature in the O K-edge of highly catalytically active X-ray amorphous iridium oxides that we have identified as O 2p hole states forming in conjunction with Ir(III). These electronic defects in the near-surface region of the anionic and cationic framework are likely critical for the enhanced activity of amorphous iridium oxides relative to their crystalline counterparts.

Structural outcomes in the Cleft Care UK study. Part 2: dento-facial outcomes.

OBJECTIVES: To compare facial appearance and dento-alveolar relationship outcomes from the CSAG (1998) and CCUK (2013) studies. SETTING AND SAMPLE POPULATION: Five-year-olds born with non-syndromic unilateral cleft lip and palate. Those in the original CSAG were treated in a dispersed model of care with low-volume operators. Those in CCUK were treated in a more centralized, high-volume operator model. MATERIALS AND METHODS: We compared facial appearance using frontal view photographs (252 CCUK, 239 CSAG) and dental relationships using study models (198 CCUK, 223 CSAG). Facial appearance was scored by a panel of six assessors using a standardized and validated outcome tool. Dento-alveolar relationships were scored by two assessors using the 5-Year-Olds' Index. Ordinal regression was used to compare results between surveys. RESULTS: Excellent or good facial appearance was seen in 36.2% of CCUK compared with 31.9% in CSAG. In CCUK, 21.6% were rated as having poor or very poor facial appearance compared with 27.6% in CSAG. The percentage rated as having excellent or good dento-alveolar relationships was 53.0% in CCUK compared with 29.6% in CSAG. In CCUK, 19.2% were rated as having poor or very poor dento-alveolar relationships compared to 36.3% in CSAG. The odds ratios for improved outcome in CCUK compared to CSAG were 1.43 (95% CI 1.03, 1.97) for facial appearance and 2.29 (95% CI 1.47, 3.55) for dento-alveolar relationships. CONCLUSIONS: Facial and dento-alveolar outcomes were better in CCUK children compared to those in CSAG.

Centralization of cleft care in the UK. Part 6: a tale of two studies.

OBJECTIVES: We summarize and critique the methodology and outcomes from a substantial study which has investigated the impact of reconfigured cleft care in the United Kingdom (UK) 15 years after the UK government started to implement the centralization of cleft care in response to an earlier survey in 1998, the Clinical Standards Advisory Group (CSAG). SETTING AND SAMPLE POPULATION: A UK multicentre cross-sectional study of 5-year-olds born with non-syndromic unilateral cleft lip and palate. Data were collected from children born in the UK with a unilateral cleft lip and palate between 1 April 2005 and 31 March 2007. MATERIALS AND METHODS: We discuss and contextualize the outcomes from speech recordings, hearing, photographs, models, oral health and psychosocial factors in the current study. We refer to the earlier survey and other relevant studies. RESULTS: We present arguments for centralization of cleft care in healthcare systems, and we evidence this with improvements seen over a period of 15 years in the UK. We also make recommendations on how future audit and research may configure. CONCLUSIONS: Outcomes for children with a unilateral cleft lip and palate have improved after the introduction of a centralized multidisciplinary service, and other countries may benefit from this model. Predictors of early outcomes are still needed, and repeated cross-sectional studies, larger longitudinal studies and adequately powered trials are required to create a research-led evidence-based (centralized) service.

The oxidation of copper catalysts during ethylene epoxidation.

The oxidation of copper catalysts during ethylene epoxidation was characterized using in situ photoemission spectroscopy and electron microscopy. Gas chromatography, proton-transfer reaction mass spectrometry and electron-ionization mass spectrometry were used to characterize the catalytic properties of the oxidized copper. We find that copper corrodes during epoxidation in a 1 : 1 mixture of oxygen and ethylene. The catalyst corrosion passes through several stages, beginning with the formation of an O-terminated surface, followed by the formation of Cu2O scale and eventually a CuO scale. The oxidized catalyst exhibits measurable activity for ethylene epoxidation, but with a low selectivity of <3%. Tests on pure Cu2O and CuO powders confirm that the oxides intrinsically exhibit partial-oxidation activity. Cu2O was found to form acetaldehyde and ethylene epoxide in roughly equal amounts (1.0% and 1.2% respectively), while CuO was found to form much less ethyl aldehyde than ethylene epoxide (0.1% and 1.0%, respectively). Metallic copper catalysts were examined in extreme dilute-O2 epoxidation conditions to try and keep the catalyst from oxidizing during the reaction. It was found that in feed of 1 part O2 to 2500 parts C2H4 (PO2 = 1.2 × 10(-4) mbar) the copper surface becomes O-terminated. The O-terminated surface was found to exhibit partial-oxidation selectivity similar to that of Cu2O. With increasing O2 concentration (>8/2500) Cu2O forms and eventually covers the surface.

An electronic criterion for assessing intrinsic brittleness of metallic glasses.

Bulk metallic glasses (BMGs) are characterized by a number of remarkable physical and mechanical properties. Unfortunately, these same materials are often intrinsically brittle, which limits their utility. Consequently, considerable effort has been expended searching for correlations between the phenomenologically complex mechanical properties of metallic glasses and more basic properties, such correlations might provide insight into the structure and bonding controlling the deformation properties of BMGs. While conducting such a search, we uncovered a weak correlation between a BMG's work function and its susceptibility to brittle behavior. We argue that the basis for this correlation is a consequence of a component of the work function - the surface dipole - and a fundamental bond property related to the shape of the charge density at a bond critical point. Together these observations suggest that simple first principle calculations might be useful in the search for tougher BMGs.

Cardiologists are more willing to prescribe ß-blockers than respiratory physicians: an Australasian clinical scenario survey.

BACKGROUND/AIMS: Recent data show great benefit from beta adrenergic blocking drug (ß-blocker) use in heart failure and has resulted in increased use of these established agents. Older data caution against their use in patients with reversible airways disease because of risks of bronchoconstriction. Anecdotally, we noted a difference in willingness to prescribe ß-blockers by cardiologists and respiratory physicians, especially for patients with coexisting airways disease. We sought to test this difference. METHODS: Nine clinical scenarios were created, tested and emailed to all members of the Cardiac and Thoracic societies of Australasia. Scenarios combined varying degrees of benefit and risk (bronchoconstriction). An inducement to return questionnaires was applied. RESULTS: Cardiologists and respiratory physicians were similarly willing to prescribe ß-blockers for patients at little risk of bronchoconstriction, irrespective of potential benefit. Cardiologists were more willing to prescribe ß-blockers than respiratory physicians for patients at greater risk of bronchoconstriction, particularly when the potential therapeutic benefit was greater. CONCLUSIONS: Our perception that cardiologists were more willing to prescribe ß-blockers than respiratory physicians was confirmed. This probably results from a difference in focus (namely focus on benefit by cardiologists vs focus on risk by respiratory physicians), although other factors including awareness of limitations of pulmonary function testing by respiratory physicians may have been involved. Until better tests are available (that discriminate between patients who are likely to suffer bronchoconstriction from those who are not), it is likely that this difference between the specialties will remain.

Smoking cessation post-discharge following nicotine replacement therapy use during an inpatient admission.

BACKGROUND: Cigarette smoking remains a health issue despite declining prevalence in Australia. The burden of tobacco-related morbidity affects hospitals, particularly those in lower socioeconomic areas where prevalence is highest. AIM: We have shown that nicotine replacement therapy (NRT) use during hospitalization increases motivation to quit post-discharge. We postulated that subjects using the nicotine patch post-discharge, in comparison to the inhaler, would have higher rates of abstinence at 12 months after discharge. The aim was to compare the efficacy of the nicotine patch or inhaler formulation for cessation post-discharge, following use during admission. METHODS: Post-discharge, subjects chose their preferred formulation (patch or inhaler) based on their experience with NRT during admission. Tailored, medium-intensity support was provided with subsidized NRT during outpatient visits. Subjects were followed for 12 months. Exhaled breath CO confirmed non-smoking. RESULTS: Of 123 subjects enrolled, 37 elected to use the inhaler, 50 the patch and 36 no NRT. At 12 months continuous abstinence rates were 38%, 38% and 25% respectively. DISCUSSION: This study built upon the 'teachable moment' provided by hospitalization and the inpatient use of NRT, encouraging cessation post-discharge. Both NRT formulations provided similar 12 month cessation rates, and were superior to those achieved by subjects electing not to use NRT. Although the patch was the most popular formulation, the inhaler provided an equally efficacious alternative which addressed other facets of cigarette addiction. Subjects electing not to use NRT were less successful. Continuous abstinence rates were equivalent to community-based studies using NRT. We recommend a similar programme to other hospitals.

Smoking prevalence and perspectives on smoking on campus by employees in Australian teaching hospitals.

BACKGROUND: Cigarette smoking prevalence has been declining over decades in Western countries especially in higher socioeconomic groups. Employees of Australian hospitals span the socioeconomic spectrum, but there are few data on smoking prevalence from these workplaces. Because smoking is a health hazard, some argue that it should be banned on hospital premises, but employees' opinions appear not to have been widely canvassed. Cigarette smoking is a particular problem in hospitals because of the need for prolonged abstinence by immobile patients and the stressors that accompany life-and-death events for patients and/or relatives. The Queen Elizabeth Hospital has had a Stop Smoking Service for >10 years, but how smoking prevalence has changed and how it compares with similar hospitals is unknown. AIMS: The aims of this study were (i) to determine smoking prevalence by employees of The Queen Elizabeth Hospital and to compare this with employees of other hospitals and (ii) to ascertain employees' perspectives regarding smoking on hospital grounds. METHODS: Single page questionnaires were forwarded to employees of four South Australian/Northern Territory hospitals enquiring about smoking status, employment category, views about smoking on hospital premises, etc. Responses were voluntary. RESULTS: Response rates were 39-59%. Smoking prevalence has steadily declined at The Queen Elizabeth Hospital and is now 8.4%. Prevalence at comparator hospitals was approximately double this value. Most staff thought the visibility of smoking was problematic, but support for providing smoking area/s was greater than for a hospital-wide ban. CONCLUSIONS: The ongoing decline in smoking prevalence at The Queen Elizabeth Hospital is probably the result of the Staff Stop Smoking Service.

Craving control using nicotine replacement therapy in a teaching hospital.

BACKGROUND: A period of hospitalisation is perhaps the longest period of enforced 'temporary abstinence' smokers have to endure and hence many crave during their admission. Cravings may result in patients' smoking on hospital premises. Nicotine replacement may reduce cravings, decrease smoking on hospital grounds and increase interest in quitting post-discharge. AIM: The aim of this study was to compare the efficacy of two nicotine formulations in controlling inpatient cravings and enthusiasm for quitting post-discharge. METHODS: Inpatients who were smokers were randomised to nicotine patch or inhaler on alternating days. Patients selected their preferred formulation, which was then used for the duration of the hospital stay. Craving control and formulation preference were assessed by visual analogue scales (VAS), and interest in quitting on a 3-point scale. Abstinence was confirmed by exhaled breath CO monitoring. RESULTS: Patches were preferred by 64% of the 367 subjects. Fewer patients went outside to smoke after either formulation (37% before, 5% after enrolment). Cravings were reduced by both nicotine formulations (mean VAS score fell from 7.5 to 1.7). Interest in quitting post-discharge increased. Estimated mean exposure to nicotine was 5 mg/day (inhaler), 15 mg/day (transdermal patch) compared with 30 mg/day (cigarettes) before hospitalisation. CONCLUSIONS: Many smokers crave and some smoke outside during a hospital admission. While the patch was the preferred formulation of nicotine replacement therapy, both were effective in reducing cravings, increasing motivation for quitting post-discharge and improving Hospital 'image' by reducing smoking on campus. Nicotine replacement therapy should be made available to inpatients in all hospitals and other places of enforced prolonged abstinence.

Frequently discordant results from therapeutic drug monitoring for digoxin: clinical confusion for the prescriber.

BACKGROUND: Digoxin remains a commonly prescribed medication for the treatment of congestive cardiac failure or atrial tachyarrhythmias. Its utility is offset by its narrow therapeutic index requiring regular blood concentration monitoring. Recent evidence suggests that a lower therapeutic range (0.5- 0.8 mg/L, or 0.6-1.0 nmol/L) is associated with reduced mortality in patients with congestive cardiac failure. Therapeutic drug monitoring for digoxin is carried out by immunoassays that are well established in routine clinical practice. Laboratories using different immunoassays may be involved in monitoring individual patients throughout the protracted course of therapy. These results should be concordant to ensure consistent dose individualization and optimum clinical management. We have investigated the discordance in digoxin measurements involving five different laboratories across the Adelaide metropolitan area. METHODS: Aliquots from routine digoxin samples (n = 261) were analysed by accredited laboratories using commercially available immunoassays. RESULTS: The results showed that 119 (46%) of 261 samples were so varied that a different clinical outcome was indicated when reviewed by the treating physician. The differences between the highest and lowest readings from any one sample were also substantial, with 45% of the measurements exceeding 0.3 microg/L. CONCLUSIONS: Our study shows the considerable variation in the routine monitoring of digoxin. This makes therapeutic drug monitoring difficult to interpret and complicates clinical management when treating physicians are endeavouring to avoid toxicity and optimize dosing. These results raise a significant concern for the quality of therapeutic drug monitoring of digoxin and have direct repercussions on patient care.

Aminoglycoside clearance is a good estimate of creatinine clearance in intensive care unit patients.

The aim of this study was to determine whether creatinine clearance can be estimated as well by clearance of gentamicin/tobramycin as by routine, non-invasive estimates in the intensive care unit. The volume of distribution and clearance values for gentamicin/tobramycin were obtained using first order kinetics and an estimate of creatinine clearance derived. Seven estimates of renal function (Cockroft-Gault, MDRD4 and MDRD6 equations, two- and 24-hour urine estimates, two equations utilising Cystatin C concentrations) were compared to the gentamicin/tobramycin clearance estimate in 100 intensive care unit patients. The gentamicin clearance estimate was at least as reliable as other estimates. The two-hour was less reliable than the 24-hour urine estimate. The Cockroft-Gault appeared to out-perform the MDRD equation estimates. The MDRD4 was not as reliable as the MDRD6 estimate. Cystatin C estimates appeared not as reliable as the gentamicin estimate of renal function. The gentamicin/tobramycin estimate is at least as good as other estimates and it is available sooner than most others. It should be used in all patients who are prescribed gentamicin. The two-hour urine and MDRD4 estimates should not be used in the intensive care unit.

The effects of gold and Co-adsorbed carbon on the adsorption and thermal decomposition of acetic acid on Pd{111}.

The growth and annealing behavior of ultrathin Au films on Pd{111} were monitored with scanning tunneling microscopy (STM) and medium energy ion scattering (MEIS). The adsorption of acetic acid on both clean and deliberately carbon-contaminated bimetallic surfaces was investigated with reflection absorption infrared spectroscopy (RAIRS) and temperature-programmed desorption (TPD). We report that the surface chemistry of acetic acid is strongly modified by the presence of Au in the bimetallic surface which acts both to stabilize adsorbed acetate and to decrease the tendency of acetic acid to decompose on adsorption to produce adsorbed carbon. The adsorption of acetic acid at 300 K is found to cause measurable segregation of Pd to the surface for all surface compositions tested.

Investigating the mechanism of chiral surface reactions: the interaction of methylacetoacetate with (S)-glutamic Acid modified Ni{111}.

The enantioselective hydrogenation of beta ketoesters over Ni-based catalysts is a rare example of a heterogeneously catalyzed chiral reaction. The key step in catalyst preparation is the adsorption from solution of chiral molecules (modifiers). One particularly interesting modifier is (S)-glutamic acid because the dominant enantiomeric product in the catalytic reaction depends upon the modification temperature. We report a reflection absorption infrared spectroscopy (RAIRS) study of the adsorption of methylacetoacetate (the simplest beta ketoester) onto (S)-glutamic acid modified Ni{111} surfaces as functions of the modifier coverage and modification temperature. We show that the sticking probability of methylacetoacetate is close to 0 on saturated (S)-glutamic acid covered surfaces. At lower modifier coverage, methylacetoacetate adsorption can occur. Adsorption of methylacetoacetate onto a Ni{111} surface modified by (S)-glutamic acid at 300 K results in the diketo tautomeric form, with evidence being observed for a 1:1 interaction between zwitterionic (S)-glutamate and methylacetoacetate. In contrast, adsorption of methylacetoacetate onto a Ni{111} surface modified by (S)-glutamic acid at 350 K occurs exclusively in the enol tautomeric form. The implications for the heterogeneous catalytic reaction are discussed.

Effects of doxorubicin on human dental pulp cells in vitro.

There is substantial information concerning the effects of continuous exposure to supratherapeutic or therapeutic concentrations of doxorubicin on human molar pulpal cells; the effects of continuous exposure to subtherapeutic concentrations of this agent are undetermined. To this end, we studied the proliferation of human fibroblasts and pulpal cells and their pattern of mineralized nodule deposition in vitro. Cell proliferation was assessed at 1, 3, 5, and 7 days from populations with either no exposure (control) or exposure to 10(-6)-10(-9) mol/L doxorubicin. Mineralized nodule deposition and calcium-45 incorporation were assessed at 7 and 21 days of culture. Data were compared by factorial ANOVA and a post-hoc Tukey test. 10(-6) and 10(-7) mol/L doxorubicin significantly reduced the total number of viable pulpal cells in cultures from days 1 to 3 (p < 0.05); doxorubicin 10(-6)-10(-9) mol/L significantly inhibited cell proliferation (p < 0.05) and DNA synthesis 5 days after plating (p < 0.001). After 21 days, doxorubicin 10(-6)-10(-8) mol/L significantly decreased calcium-45 incorporation into pulpal cultures (p < 0.001); all dilutions significantly reduced the number of mineralized nodules within the 21-day pulpal cultures (p < 0.05). In addition, all dilutions of doxorubicin significantly inhibited fibroblast cell proliferation and incorporation of [(3)H]thymidine. In contrast, the fibroblast cultures did not produce mineralized nodules, suggesting that the mineralized nodules within the pulpal cell cultures did not result from dystrophic calcification. Thus, exposure to subtheraputic doxorubicin concentrations has potential adverse effects on mineralized tissue formation within the pulp, which could affect the rates of reparative dentin deposition within the tooth pulps of patients receiving this chemotherapeutic agent.

Molecular ordering and adsorbate induced faceting in the Ag{110}-(S)-glutamic acid system.

The adsorption of the amino acid, (S)-glutamic acid, was investigated on Ag{110} as a function of coverage and adsorption temperature using the techniques of scanning tunneling microscopy, low energy electron diffraction, and reflection absorption infrared spectroscopy. In the monolayer, (S)-glutamic acid was found to adsorb predominantly in the anionic glutamate form. Several discrete ordered adlayer structures were observed depending on preparation conditions. In addition, (S)-glutamic acid was found to induce both one- and two-dimensional faceting of the Ag{110} surface. In some cases, evidence was found that the 2-D faceting involved the creation of a chiral facet distribution. A comparison is made of the Ag/(S)-glutamic acid system with analogous studies of amino acids on Cu.

Biogenic stabilization of intertidal sediments: the importance of extracellular polymeric substances produced by benthic diatoms.

The sediment-stabilizing effect of benthic diatoms was investigated in a laboratory setting. Axenic cultures of the benthic diatoms Nitzschia cf. brevissima and Cylindrotheca closterium were inoculated in Petri dishes containing sand and incubated under axenic conditions. By ensuring aseptic routines throughout the experiments, interference from other organisms occurring with diatoms in natural photothrophic biofilms was avoided. This allowed the examination of the role of benthic diatoms in sediment stabilization. Increases in the critical erosion shear stress of the sediment were observed in the presence of both diatom taxa relative to sterile sediment. However, N. cf. brevissima was more effective than C. closterium. Values of critical shear stress in the experimental system were in the same range as those observed in natural biofilms, which indicates that diatoms are important agents for biogenic stabilization. Extracellular carbohydrate contents in the microcosms were similar for both diatom species. However, in the presence of N cf. brevissima, extracellular carbohydrate correlated significantly to critical shear stress, explaining up to 80% of the variation, whereas this was not the case for C. closterium. Therefore, it was concluded that the quantity of extracellular polymeric substances (EPS) alone did not explain the biogenic stabilization. Observed adsorption of EPS to sediment particles depended on the relative amount of uronic acids in the exopolymers. Using fluorescently labeled lectins, confocal laser scanning microscopy showed that EPS secretion by N. cf. brevissima resulted in ordered three-dimensional matrix structures. It is suggested that the structuring of EPS plays an prominent role in the process of biostabilization, and that diatoms such as N. cf. brevissima are actively involved in producing the structure of EPS, whereas others such as C. closterium do not do so to the same extent.

The nucleotide-binding site of the sarcoplasmic reticulum Ca-ATPase is conformationally altered in aged skeletal muscle.

Cellular conditions in senescent skeletal muscle have been shown to result in the loss of conformational stability of the sarcoplasmic reticulum (SR) Ca-ATPase. To identify underlying structural features of age-modified Ca-ATPase, we have utilized the fluorescence properties of protein-bound probes to assess both local and global structure. We find conformational changes that include an age-related decrease in the apparent binding affinity to high affinity calcium sites detected by fluorescence signals in both tryptophans within nearby membrane-spanning helices and fluorescein isothiocyanate (FITC) bound distally to Lys(515) within the nucleotide-binding site. In addition, a substantial (80%) age-related increase in the accessibility to soluble quenchers of fluorescence of FITC is observed without concomitant changes in bimolecular quenching constants (k(q)) for protein-bound IAEDANS, also within the nucleotide-binding domain, and tryptophans within the membrane. Using fluorescence resonance energy transfer to measure distances between IAEDANS and FITC across the nucleotide-binding domain, we find no significant age-related change in the mean donor-acceptor distance; however, significant increases are observed in the conformational heterogeneity of this domain, as assessed by the width at half-maximum (HW) of the distance distribution, increasing with age from 29.4 +/- 0.8 A to 42.5 +/- 1. 1 A. Circular dichroism indicates that the average secondary structure is unaltered with age. Thus, these data suggest tertiary structural alterations in specific regions around the nucleotide-binding site rather than global conformational changes.

Mechanisms of drug-induced diarrhoea in the elderly.

In the rapidly increasing elderly population, diarrhoea as a result of drug therapy is an important consideration. The elderly consume a disproportionately large number of drugs for multiple acute and chronic diseases. Drugs can compromise both immune and nonimmune responses. Aging decreases the quality and proportion of T cells which in turn reduces the production of secretory IgA, the primary immune response of the gut. Acid production in the stomach decreases with increasing age and this compromise its vital 'self-sterilising' function, thus increasing the risk of diarrhoea due to viral, bacterial and protozoal pathogens. Other nonimmune defence mechanisms include the motility of the small intestine and the host-protective commensal bacteria of the colon. Drug induced hypomotility may result in bacterial overgrowth, deconjugation of bile salts and diarrhoea. Less commonly, diarrhoea may occur due to hypermotility because of a cholinergic-like syndrome. In the colon the host-protective commensal bacteria provide a powerful defence against pathogens. Disruption of this commensal population by antibiotic therapy may result in Clostridium difficile supra-infection which causes diarrhoea through toxin production. This is especially important in the elderly patient on chemotherapy for malignancy and those with multiple diseases. The organism responds to vancomycin, metronidazole and bacitracin. Metronidazole is the suggested drug of choice, with vancomycin reserved for relapses. Drugs also cause diarrhoea by interfering with normal physiological processes. Drugs impair fluid absorption by activating adenylate cyclase within the small intestinal enterocyte which increases the level of cyclic AMP. This causes active secretion of Cl- and HCO3-, passive efflux of Na+, K+ and water and inhibition of Na+ and Cl- into the enterocyte. Examples of these drugs (secretagogues) are bisacodyl, misoprostol and chenodeoxycholic acid (used to dissolve cholesterol gallstones). Drugs may also affect a second mechanism that regulates water and electrolyte transport, the Na+, K+ exchange pump. The energy for this pump is provided by the ATPase mediated breakdown of ATP. ATPase may be inhibited by digoxin, auranofin, colchicine and olsalazine. A number of drugs cause osmotic diarrhoea including antacids containing magnesium trisilicate or hydroxide. Lactulose is being used increasingly in compensated liver disease to increase protein tolerance and prevent hepatic encephalopathy. Sorbitol, an osmotic laxative agent also used in some liquid pharmaceutical preparations, induces diarrhoea by virtue of its osmotic potential. Another mechanism by which drugs cause diarrhoea is by mucosal damage of the small and large bowel. In the small intestine mucosal damage causes diarrhoea and fat malabsorption, as may occur with neomycin and colchicine. In the colon, for example, gold salts and penicillamine cause colitis of varying severity. Though the causes of diarrhoea are diverse, a drug-associated aetiology should always be considered and actively sought and addressed to prevent the complications of dehydration, electrolyte imbalance and undernutrition.

Smoking habits and cessation programme in an Australian teaching hospital.

BACKGROUND: Data on prevalence of cigarette smoking by hospital employees are limited in Australia, but anecdotal evidence suggests that many health sector employees continue to smoke despite abundant evidence regarding the harmful effects of this habit. Nicotine is an addictive drug and arguably this should be known better in the health industry than in any other industry. Despite having this knowledge at their disposal, health sector employers rarely provide assistance to employees, relying instead on restrictive policies to reduce smoking in the workplace. METHODS: To assist employees to quit smoking, we instituted a medium intensity Stop Smoking Programme, run by a clinical pharmacist offering nicotine patches and support on a weekly basis. A principal aim of the service was to redress the imbalance between the availability of cigarettes and the most effective nicotine replacement therapy, the trandermal nicotine patch. Following 18 months operation of this service, we surveyed hospital employees to ascertain smoking rates and views on smoking cessation in this South Australian teaching hospital. RESULTS: In the first 18 months of operation, 111 staff members availed themselves of the service. At the first follow up period (three months), 21 were not contactable, 29 were successful in not smoking and 61 were still smoking. Six of the 29 who were not smoking at three months resumed smoking by six months, and a further four resumed smoking by 12 months. At the time of this report, 12 of the remaining 19 non smokers had completed two years since quitting and a further three of these had resumed regular smoking by this time. The cost of providing the service was modest at approximately $180.00 per known successful quitter. Results from the survey showed that 12.4% of hospital employees were regular smokers. Smoking prevalence was not equally distributed with female employees being twice as likely to smoke as their male counterparts and employees in the catering department having the highest smoking prevalence (23.8%). CONCLUSIONS: Although the prevalence of cigarette smoking by employees of this teaching hospital is lower than for the general community, health sector employers can reduce smoking prevalence further by providing assistance to their employees to quit smoking. The Stop Smoking Programme we describe is effective and could be replicated by other hospitals and similar organisations.