Onset of cohesion in cement paste

It is generally agreed that the cohesion of cement paste occurs through the formation of a network of nanoparticles of a calcium-silicate-hydrate ("C-S-H"). However, the mechanism by which these particles develop this cohesion has not been established. Here we propose a dielectric continuum model which includes all ionic interactions within a dispersion of C-S-H particles. It takes into account all co-ions and counterions explicitly (with pure Coulomb interactions between ions and between ions and the surfaces) and makes no further assumptions concerning their hydration or their interactions with the surface sites. At high surface charge densities, the model shows that the surface charge of C-S-H particles is overcompensated by Ca2+ ions, giving a reversal of the apparent particle charge. Also, at high surface charge densities, the model predicts that the correlations of ions located around neighboring particles causes an attraction between the particle surfaces. This attraction has a range of approximately 3 nm and a magnitude of 1 nN, values that are in good agreement with recent AFM experiments. These predictions are stable with respect to small changes in surface-surface separation, hydrated ion radius, and dielectric constant of the solution. The model also describes the effect of changes in cement composition through the introduction of other ions, either monovalent (Na) or multivalent (aluminum or iron hydroxide).

Cost-effectiveness of clopidogrel in acute coronary syndromes in Sweden: a long-term model based on the CURE trial

OBJECTIVES

The purpose of this study was to evaluate the long-term cost-effectiveness of clopidogrel on top of standard therapy (including ASA) in patients with acute coronary syndromes without ST-segment elevation in Sweden.

METHODS AND RESULTS

Incremental cost-effectiveness ratios (ICER) were assessed using a Markov model with transition probabilities estimated from the Swedish hospital discharge and cause of death registers. Patients were assumed to be treated for 1 year, with treatment effects (RR = 0.8) and costs taken from the Clopidogrel in Unstable Angina to prevent Recurrent ischaemic Events Trial. Two scenarios were analysed: with patients similar to those in the trial and with patients similar to those from the register. In the first scenario, the predicted net direct cost was 160 euro and the net total cost -54 euro, which with an incremental survival of 0.12 years give the ICER of 1365 euro per life-year gained from the health care payer perspective (including direct costs) and cost savings from the societal perspective (also including indirect costs). The net costs in the second scenario were 149 euro, giving an ICER of 1009 euro for both perspectives.

CONCLUSIONS

Adding clopidogrel to standard therapy including ASA is cost-effective in the studied setting and compares favourably with other cardiovascular treatment and prevention strategies.

Fracture risk following an osteoporotic fracture

The aim of this study was to examine the pattern of fracture risk following a prior fracture at the spine, shoulder or hip. We studied 1918 patients with fractures at these sites identified from the Department of Radiology in Malmo who were followed for 5 years. Poisson regression was used to compute fracture rates immediately after the initial fracture and at 5 years thereafter in men and women aged 60 or 80 years. Immediate fracture risk was higher than that of the general population, more markedly so at the age of 60 than at 80 years. At the age of 60 years, the risk of hip, forearm and spine fractures were significantly increased following a prior spine, hip or shoulder fracture in men. A similar pattern was seen in women, except that the increase in risk of forearm fracture following a spine or hip fracture was not statistically significant. The incidence of further fractures at the shoulder, spine or hip fell with time after the first fracture, a fall that was significant for all fractures after a shoulder fracture, hip fracture after a spine fracture, and hip and spine fractures after a hip fracture. We conclude that the risk of a subsequent fracture immediately after an osteoporotic fracture is highest immediately after the event. This provides a rationale for very early intervention immediately after fractures to avoid recurrent fractures.

Mortality after osteoporotic fractures

The aim of this study was to examine the pattern of mortality following osteoporotic fractures at the spine, shoulder, hip, and forearm. We studied 2,847 patients with fractures at these sites identified from the radiology department in Malmö, Sweden. Poisson regression was used to compute mortality immediately after the fracture and with time. Mortality immediately after fracture was significantly higher in fracture cases than in the general population except for forearm fractures in both men and women. Mortality was higher in men than in women, but not different when adjusted for sex-specific population risks. For spine, shoulder, and hip fracture, mortality fell after the 1st year, an effect that was most marked for patients with spine fractures. The decrease in mortality risk with time was significant for hip, vertebral, and shoulder fracture. We conclude that the risk of death is increased in patients with osteoporotic fractures and that the highest risk is found immediately after the fracture event. The decreasing mortality with time after fracture may be due in part to a decrease in deaths causally related to the fracture. The extent to which early intervention for osteoporosis might avoid some of these deaths is unknown.

First Report of Solanum physalifolium as a Host Plant for Phytophthora infestans in Sweden

In the early summer of 2003, lesions resembling those caused by Phytophthora infestans (Mont.) de Bary on potato were observed on Solanum physalifolium Rusby var. nitidibaccatum (Bitter) Edmonds (2) that was growing as a weed in a parsnip (Pastinaca sativa) field in southern Sweden. When infected leaves of S. physalifolium were observed under the microscope (×200 magnification), sporangia with the same shape and size as those of P. infestans were observed. Pieces of infected leaves of S. physalifolium were put under tuber slices of S. tuberosum (cv. Bintje) in petri dishes and kept at 20°C. After 4 days, mycelium grew through the slices and sporulated profusely. The sporangia on the slices were of the same shape and size as those observed on the infected S. physalifolium leaves. In Sweden, the ratio of A1 and A2 mating types of P. infestans is 50:50, and oospores are commonly found in infected potato crops (1), so isolates from S. physalifolium were tested for mating type by growing them together with reference isolates of a known mating type on agar plates. Nine of the tested isolates were A1 mating type and six were A2 mating type. One self-fertile isolate was found. Naturally infected leaves of S. physalifolium were incubated at 20°C at 100% relative humidity so the lesions could coalesce and to facilitate oospore formation. After 5 days, oospores identical to those of P. infestans were observed under the microscope (×200 magnification). Sporangia produced by isolates originating from S. physalifolium and S. tuberosum were harvested, and a suspension containing 10⁴ sporangia per ml from each isolate was prepared. Five leaves each of S. nigrum, S. physalifolium, and S. tuberosum (cv. Bintje), were inoculated with 10 μl of each sporangial suspension. Inoculated leaves were incubated in sealed petri dishes at 15°C. After 4 days, all S. tuberosum leaves were infected. After 7 days, two of five leaves of S. physalifolium inoculated with the S. tuberosum isolate and two of five S. physalifolium leaves inoculated with the isolate from S. physalifolium were infected. All lesions produced sporangia similar to those formed by P. infestans. S. nigrum was not infected by any of the isolates. The ability of S. physalifolium to act as a host plant for P. infestans producing sporangia during the growing season and oospores for survival between growing seasons may increase the problems of controlling late blight in potato in Sweden. References: (1) J. Dahlberg et al. Field survey of oospore formation by Phytophthora infestans. (Poster Abstr.) Pages 134-135 In: Late Blight: Managing the Global Threat. Proc Global Late Blight Conf. Charlotte Lizarraga, ed. Centro Internacional De La Papa, On-line publication, ISBN 929060-215-5, 2002. (2) J. M. Edmonds. Bot. J. Linn. Soc. 92:1, 1986.

The cost-effectiveness of fondaparinux compared with enoxaparin as prophylaxis against thromboembolism following major orthopedic surgery

BACKGROUND

The selective antithrombotic fondaparinux is more effective than the low-molecular-weight heparin enoxaparin for prevention of venous thromboembolism (deep-vein thrombosis [DVT] or pulmonary embolism) in patients undergoing major orthopedic surgery, but its cost-effectiveness is undetermined.

OBJECTIVES

To evaluate the cost-effectiveness of fondaparinux relative to enoxaparin as prophylaxis against venous thromboembolism (VTE) for patients undergoing total hip replacement, total knee replacement or hip fracture surgery in the UK.

PATIENTS/METHODS

A decision analysis model was created simulating the impact of fondaparinux and enoxaparin on patient outcomes and costs over various time points up to 5 years following surgery. The main outcome measures were treatment costs per patient and the incidence of clinical VTE and VTE-related deaths. A weighted (combined) cohort reflects the proportion of patients undergoing these procedures in 2000/2001.

RESULTS

In the combined cohort, compared with enoxaparin, fondaparinux is expected to produce 20 fewer clinical VTE events and 3.2 fewer VTE-related deaths per 1000 procedures at 5 years. Cost savings at 5 years are pound 27 per patient with fondaparinux (discounted at 6% per year). In each of the three surgical groups, fondaparinux leads to lower expected costs per patient and to a smaller number of VTE events and VTE-related deaths. RESULTS are sensitive to the price difference between fondaparinux and enoxaparin and variation in the rate of late DVT. The analysis is robust to variations in all other key parameters.

CONCLUSIONS

Compared with enoxaparin, fondaparinux is more effective and reduces costs to the healthcare system. At current prices, fondaparinux is the recommended strategy in the UK for prophylaxis following major orthopedic surgery.

The Cobas Amplicor MTB test for detection of Mycobacterium tuberculosis complex from respiratory and non-respiratory clinical specimens

The Cobas Amplicor MTB test is a polymerase chain reaction (PCR) technique commonly used for direct detection of Mycobacterium tuberculosis in clinical samples. This assay is only validated for respiratory specimens, but many physicians also request PCR analyses for non-respiratory ones. 877 respiratory and 564 non-respiratory specimens were analysed by this test. Using culture results as standard, the sensitivity, specificity, positive (PPV) and negative predictive values (NPV) of the PCR were, respectively, 97.9%, 100%, 100% and 94.4% for smear-positive respiratory specimens, 68.8%, 99.2%, 87.5% and 97.5% for smear-negative respiratory samples, 57.8%, 98.6%, 78.8% and 96.4% for all non-respiratory specimens, and 42.4%, 98.6%, 66.7% and 96.4% for smear-negative non-respiratory specimens. 154 cerebrospinal fluid samples were analysed and the sensitivity, specificity, PPV and NPV were 55.6%, 97.2%, 55.6% and 97.2%, respectively. These results indicate that the Cobas Amplicor MTB test enables detection of tuberculosis in respiratory specimens, but does not perform well enough in non-respiratory specimens. The method fails particularly in cases where a reliable and rapid test is urgently needed, e.g. in tuberculous meningitis.

Health economics in the Hypertension Optimal Treatment (HOT) study: costs and cost-effectiveness of intensive blood pressure lowering and low-dose aspirin in patients with hypertension

OBJECTIVES

To investigate the marginal cost-effectiveness of different targets for the reduction of blood pressure and the cost-effectiveness of adding acetylsalicylic acid (ASA) to the treatment of hypertension.

DESIGN

Patients with hypertension were randomized to three target groups for blood pressure; < or =90, < or =85 and < or =80 mmHg. Patients were also randomly assigned ASA and placebo. The average follow-up time was 3.8 years. The direct costs for drugs, visits, hospitalizations, and side-effects were calculated and related to clinical outcome.

SETTING

Resource utilization data from all the 26 countries in the study were pooled, and Swedish unit costs were applied to the aggregated resource utilization.

SUBJECTS

A total of 18 790 patients, 50-80 years of age (mean 61.5 years), with a diastolic blood pressure between 100 and 115 mmHg (mean 105 mmHg).

INTERVENTIONS

Antihypertensive treatment with the long-acting calcium antagonist felodipine was given to all patients. Additional therapy and dose increments in four further steps were prescribed to reach the randomized target blood pressure. Fifty per cent of the patients were randomized to a low dose, 75 mg daily, of acetylsalicylic acid.

MAIN OUTCOME MEASURES

Direct health care costs, major cardiovascular (CV) events (myocardial infarction and stroke) and CV death.

RESULTS

The average cost of drugs and visits increased with more intensive treatment. The increase in treatment costs was partly but not fully offset by a nonsignificant reduction in the cost of CV hospitalizations. For patients with diabetes there were no significant differences in total cost between the target groups. The cost of avoiding a major CV event was negative in the base case analysis, SEK -10 360 (CI: -78 195, 75 630), and SEK 18 450 (CI: -88 789, 192 980) in a sensitivity analysis. For patients on ASA, costs were slightly but significantly higher than for patients on placebo. The estimates of the cost of avoiding a major CV event varied between SEK 41 600 and SEK 477 400, with very wide confidence intervals.

CONCLUSIONS

The treatment cost increases as the target for hypertension treatment is lowered. In patients with diabetes, intensive treatment to a lower target is cost-effective. Because of the nonsignificant difference in events, no conclusion can be made for all patients in the study. Furthermore, no conclusive evidence was found regarding the cost-effectiveness of adding ASA to the treatment of hypertension.

The cost-effectiveness of early cabergoline treatment compared to levodopa in Sweden

The cost of Parkinson's disease (PD) is associated with the progression of the disease. Levodopa is a potent treatment for this disease, but long-term treatment results in motor complications that are associated with both costs and considerable patient discomfort. The introduction of dopamine agonists early in the treatment of PD leads to a delay in these complications, but the treatment as such is associated with higher costs. We compared the cost-effectiveness of the dopamine agonist cabergoline (with the possibility of adding levodopa later) with that of levodopa alone. A Markov model with states of the disease without motor complications defined by Hoehn and Yahr stages, and a specific state for patients with motor complications was constructed. Transition probabilities between Hoehn and Yahr states were calculated from a previously published clinical trial using an ordered probit regression model. The risk of suffering from motor complications was estimated using a Weibull model. Mortality was assumed to be the same as in the general population. Costs were estimated based on a cross-sectional study performed in southern Sweden, and only direct costs were included. In the base case the model was run for 5 years (10 cycles) and extended to 10 years in a sensitivity analysis, and costs and effects were discounted at a rate of 3%. In the base case it was predicted that the cost in the levodopa arm was 7,453 euros (67,754 Swedish crowns) compared to 11,777 euros (107,065 crowns) in the cabergoline arm. However, patients treated with cabergoline gained 0.31 years without motor complications, giving an incremental cost-effectiveness ratio for cabergoline of 13,863 euros (126,023 crowns) per year of motor complications avoided (YMA). Running the model for 10 years resulted in a more favorable cost-effectiveness ratio: 6,122 euros/YMA (55,659 crowns). The model was robust to variations in discounting rates and to variations in the estimation of costs. Although no benchmark figure pertaining specifically to Parkinson's disease has been reported to suggest the economic value of a year without motor complications (gained as a result of treatment for Parkinson's disease), US$ 60,000 per QALY gained is a figure that is often used to assess cost-effectiveness in the literature. Using this criterion, cabergoline is cost-effective if the treatment saves 0.065 QALYs. Cabergoline is even more likely to be cost-effective when also considering indirect and informal costs. More research on the relationship between motor complications and quality of life is needed.

Ankle-brachial index and mortality in a cohort of questionnaire recorded leg pain on walking

OBJECTIVE

To study the association between the ankle-brachial pressure index (ABPI), premature death and the need for surgical treatment for lower limb ischaemia.

DESIGN

Population based cohort study.

SUBJECTS

Three hundred and fifty-three men and women, 50-89 years old, underwent a leg pain questionnaire and measurement of ABPI and was then followed for 10 years.

OUTCOME MEASURES

All cause mortality, vascular procedures and major amputations.

RESULTS

A low ABPI was independently associated with premature all cause mortality in the multiple regression analysis, carrying a relative risk of 3.4 (95% confidence interval 2.0-5.9) and 2.1 (1.3-3.3) for ABPIs <or=0.50 and 0.51-0.80, respectively, compared to those with ABPI >or=1.0. Individuals with an ABPI in the interval 0.81-0.99 suffered only a slight, not statistically significant risk increase compared to normals. A low ABPI at baseline implied a continuous constant increased risk of death throughout the study period. The same risk was observed among elderly (70-89, median 77 years), and in the middle aged (50-69, median 63 years) individuals. The vast majority of those subjected to vascular intervention or major amputation during follow-up had an ABPI<or=0.8 at baseline (83 and 89%, respectively). However, within that group, the individual ABPI was not predictive for surgical intervention.

CONCLUSION

The association found between an ABPI <or=0.8 and premature mortality in this cohort of symptomatic subjects implies that the ABPI is a powerful, independent predictor for premature death. The prognostic information carried by an ABPI in the interval 0.81-0.99 remains uncertain. Septuagenarians and octogenarians carry the same risk increase associated with a low ABPI as those in the middle ages.

Intervention thresholds for osteoporosis

The aim of this study was to determine the threshold of fracture probability at which interventions become cost-effective. We modeled the effects of a treatment costing $500/year, given for 5 years, that decreased the risk of all osteoporotic fractures by 35%, followed by a waning of effect for 5 years. Sensitivity analyses included a range of effectiveness (10%-50%) and a range of intervention costs (200-500 dollars/year). Data on costs and risks were from Sweden. Costs included direct costs and costs in added years of life, but excluded indirect costs due to morbidity. A threshold for cost-effectiveness of 60,000 dollars per quality-adjusted life-year (QALY) gained was used. Costs of added years were excluded in a sensitivity analysis for which a threshold value of 30,000 dollars per QALY was used. In the base case, intervention was cost-effective when treatment was targeted to women at average risk at age of >or=65 years. Irrespective of the efficacy modeled (10%-50%) or of cost of intervention (200-500 dollars/year) segments of the population at average risk could be targeted cost-effectively: The lower the intervention cost and the higher the effectiveness, the lower the age at which intervention was cost-effective. With the base case (500 dollars/year; 35% efficacy) treatment in women was cost-effective with a 10 year hip fracture probability that ranged from 1.4% at the age of 50 years to 4.4% at the age of 65 years. The exclusion of osteoporotic fractures other than hip fracture would increase the threshold to a 9%-11% 10 year probability because of the substantial morbidity from fractures other than hip fracture, particularly at younger ages. We conclude that the inclusion of all osteoporotic fractures has a marked effect on intervention thresholds, that these vary with age, and that available treatments can be cost-effectively targeted to individuals at moderately increased risk.

Revealing the cost of Type II diabetes in Europe

AIMS/HYPOTHESIS

'The Cost of Diabetes in Europe-Type II study' is the first coordinated attempt to measure total healthcare costs of Type II (non-insulin-dependent) diabetes mellitus in Europe. The study evaluated more than 7000 patients with Type II diabetes in eight countries - Belgium, France, Germany, Italy, the Netherlands, Spain, Sweden and the United Kingdom.

METHODS

A bottom-up, prevalence-based design was used, which optimised the collection of data at the national level while maintaining maximum international comparability. Effort was made to ensure consistency in terms of data specification, data collection tools and methods, sampling design, and the analysis and reporting of results. Results are reported for individual countries and in aggregate for the total study population.

RESULTS

The total direct medical costs of Type II diabetes in the eight European countries was estimated at EUR 29 billion a year (1999 values). The estimated average yearly cost per patient was EUR 2834 a year. Of these costs, hospitalisations accounted for the greatest proportion (55%, range 30-65%) totalling EUR 15.9 billion for the eight countries. During the 6-month evaluation period, 13% of the Type II diabetic patients were hospitalised, with an average of 23 days in hospital projected annually. In contrast, drug costs for managing Type II diabetes were relatively low, with antidiabetic drugs and insulin accounting for only 7% of the total healthcare costs for Type II diabetes.

CONCLUSION/INTERPRETATION

Type II diabetes mellitus is a common disease and the prevalence is expected to increase considerably in the future, especially in developing countries. Current comprehensive economic data on the costs of diabetes are required for policy decisions to optimise resource allocation and to evaluate different approaches for disease management.

Calbindin D(9k): a protein optimized for calcium binding at neutral pH

The binding of calcium ions by EF-hand proteins depends strongly on the electrostatic interactions between Ca(2+) ions and negatively charged residues of these proteins. We have investigated the pH dependence of the binding of Ca(2+) ions by calbindin D(9k). This protein offers a unique possibility for interpretation of such data since the pK(a) values of all ionizable groups are known. The binding is independent of pH between 7 and 9, where maximum calcium affinity is observed. An abrupt decrease in the binding affinity is observed at pH values below 7. This decrease is due to protonation of acidic groups, leading to modification of protein charges. The pH dependence of the product of the two macroscopic Ca(2+)-binding constants can be formally described by the involvement of two acidic groups with pK(a) = 6.6. Monte Carlo calculations show that the reduction of Ca(2+) binding is strictly determined by variable electrostatic interactions due to pH-dependent changes not only in the binding sites, but also of the overall charge of the protein.

Visual analog scales for interpretation of back and leg pain intensity in patients operated for degenerative lumbar spine disorders

STUDY DESIGN

A prospective observational study of visual analog scale (VAS) scores for pain in patients operated at one institution within the framework of a national registry.

OBJECTIVE

To describe the use of recording VAS for pain intensity in patients operated on for lumbar spine problems.

SUMMARY OF BACKGROUND DATA

There is no consensus regarding pain outcomes assessment in spine patients. Pain intensity, recorded on a VAS, is one of the most used measures. Still, many aspects of its interpretation are still debated or unclear.

METHODS

A total of 755 consecutive patients, mean age 50 years (range, 15-86 years), operated from 1993 to 1998 were included in the study; there were 420 males and 335 females. Diagnoses included herniated nucleus pulposus (45%), central stenosis (19%), lateral stenosis (14%), isthmic spondylolisthesis (9%), and degenerative disc disease (9%). Local pain, radiating pain, analgesic intake, and walking ability were recorded before surgery and at 4 and 12 months after surgery. The patients' opinions regarding the change in pain and satisfaction with the result were assessed separately. Correlation among variables reflecting perceived pain was sought.

RESULTS

Preoperative VAS mean values for local and radiating pain were significantly different in the five diagnostic groups. Significant but moderate correlation between different types of pain outcomes and with patient satisfaction was present in all cases.

CONCLUSIONS

Measuring pain intensity with VAS is a useful tool in describing spine patients. In the search for a standard in the evaluation of pain as an outcome, the differences between the various methods should be taken into account.

Focusing of the electrostatic potential at EF-hands of calbindin D(9k): titration of acidic residues

Biological functions for a large class of calmodulin-related proteins, such as target protein activation and Ca(2+) buffering, are based on fine-tuned binding and release of Ca(2+) ions by pairs of coupled EF-hand metal binding sites. These are abundantly filled with acidic residues of so far unknown ionization characteristics, but assumed to be essential for protein function in their ionized forms. Here we describe the measurement and modeling of pK(a) values for all aspartic and glutamic acid residues in apo calbindin D(9k), a representative of calmodulin-related proteins. We point out that while all the acidic residues are ionized predominantly at neutral pH, the onset of proton uptake by Ca(2+) ligands with high pK(a) under these conditions may have functional implications. We also show that the negative electrostatic potential is focused at the bidental Ca(2+) ligand of each site, and that the potential is significantly more negative at the N-terminal binding site.

Economics of drug treatment: for which patients is it costeffective to lower cholesterol?

Today's society places a great emphasis on value for money, so medical interventions must not only be shown to be effective but also be proved to be costeffective. Drug treatment is no exception. In health economics, costeffectiveness is calculated differently depending on the indication and the perspective. For cholesterol-lowering drugs (as an example) there is a difference between primary and secondary intervention. In primary prevention, the cut off value for absolute risk when treatment is costeffective varies with age and sex, but in secondary prevention, although treatment is costeffective for all groups of patients, costeffectiveness varies with age, sex, cholesterol concentration, and other risk factors. There are three complementary approaches to economic assessment of secondary prevention-analysis of the whole population, subgroup analysis, and modelling.

Exposure to hexahydrophthalic and methylhexahydrophthalic anhydrides--dose-response for sensitization and airway effects

OBJECTIVES

This study clarified the exposure-response relationships for the organic acid anhydrides (OAA) hexahydrophthalic (HHPA) and methylhexahydrophthalic (MHHPA) anhydrides and the development of specific immunoglobulin (IG) E and G antibodies and work-related symptoms.

METHODS

In an epoxy resin-using factory, air levels of OAA were determined by gas chromatography-mass spectrometry. Occupational, smoking, and medical histories (questionnaire) were obtained for 154 exposed workers and 57 referents. Work-related symptoms of the eyes and airways were recorded, and OAA metabolites were analyzed in urine. A skin-prick test with common allergens and conjugates of OAA were performed. Specific IgE (radioallergosorbent test) and IgG (enzyme-linked immumosorbent assay) antibodies were determined in serum, and spirometry was performed.

RESULTS

Air levels of the OAA were low (HHPA < 1 to 94, MHHPA < 3 to 77 microg/m3) and associated with the concentrations of the OAA metabolites in urine. Furthermore, for the exposed workers, there were high prevalences of sensitization (IgE 22%, IgG 21%), which correlated with the exposure. Neither atopy nor smoking increased this risk significantly. Furthermore, work-related symptoms were more prevalent among the exposed workers than among the referents (eyes 23% versus 14%, nose 28% versus 16%, nose bleeding 8% versus 0%, lower airways 10% versus 4%), and they were related to the exposure (adjusted prevalence odds ratios (POR) in the highest group 7.7, 3.6 and 17, respectively) and the IgE levels (POR 4.9, 3.1 and 5.6, respectively).

CONCLUSIONS

In spite of the very low OAA levels in the air and metabolites in the urine, there were high and exposure-related risks of specific IgE and IgG sensitization and of work-related symptoms for the eyes, nose (especially bleeding), and lower airways.

Cost-effectiveness of prolonged out-of-hospital prophylaxis with low-molecular-weight heparin following total hip replacement

Several studies have demonstrated that prolongation of thromboprophylaxis after elective hip replacement significantly reduces the frequency of venographically demonstrated deep vein thrombosis. This paper reports an economic evaluation of prolonged prophylaxis with low-molecular-weight heparin (LMWH), based on outcome data from one of these trials. Analysis showed a net saving per patient of 3,400 Swedish kronor. Consequently, if the costs of administering the LMWH -- which includes the cost of teaching the patient to self-administer whilst in hospital and the cost of a follow-up visit by a district nurse to ensure compliance -- are below this amount, the intervention will prove to be cost saving.

Economic burden of NSAID-induced gastropathy in Sweden

BACKGROUND

Gastrointestinal side effects carry a significant cost related to the use of NSAID medications.

METHODS

The economic burden of NSAID-induced gastric side effects is estimated using the cost-of-illness methodology. Costs are calculated using both a prevalence (top-down) approach and an incidence (bottom-up) approach.

RESULTS

Using the top-down approach, the total cost in 1998 of NSAID-induced ulcers was MSEK 329-586, direct costs accounting for 76%-83%. The bottom-up approach gives an estimate of MSEK 320, of which MSEK 290 was direct cost. About one-quarter of total costs for ulcer disease can be attributed to the use of NSAIDs.

CONCLUSIONS

Gastrointestinal side effects carry a significant cost from the use of NSAIDs, costs that are as important as the price of NSAIDs. This should be considered when choice of drug and prophylaxis is being made.

A critical investigation of the Tanford-Kirkwood scheme by means of Monte Carlo simulations

Monte Carlo simulations are used to assess the adequacy of the Tanford-Kirkwood prescription for electrostatic interactions in macromolecules. Within a continuum dielectric framework, the approach accurately describes salt screening of electrostatic interactions for moderately charged systems consistent with common proteins at physiological conditions. The limitations of the Debye-Hückel theory, which forms the statistical mechanical basis for the Tanford-Kirkwood result, become apparent for highly charged systems. It is shown, both by an analysis of the Debye-Hückel theory and by numerical simulations, that the difference in dielectric permittivity between macromolecule and surrounding solvent does not play a significant role for salt effects if the macromolecule is highly charged. By comparison to experimental data, the continuum dielectric model (combined with either an approximate effective Hamiltonian as in the Tanford-Kirkwood treatment or with exact Monte Carlo simulations) satisfactorily predicts the effects of charge mutation on metal ion binding constants, but only if the macromolecule and solvent are assigned the same or similar permittivities.

Macroscopic background gradient and radiation damping effects on high-field PGSE NMR diffusion measurements

The effects of macroscopic background gradients due to susceptibility differences at the sample interfaces and of radiation damping on pulsed-gradient spin-echo (PGSE) experiments are examined. Both phenomena can lead to the seemingly strange effect of the echo signal growing as the gradient strength increases at low applied gradient strengths. For a freely diffusing species, background gradients manifest themselves as slight concave or convex inflections in the linearized PGSE attenuation curve, depending on the polarity of the applied gradient. The various means of overcoming macroscopic background gradient problems, including bipolar gradients, and their efficacy are examined experimentally and discussed. The effects of radiation damping can also result in the attenuation curve being nonlinear but, different from the effect of background gradients, the nonlinearity does not change with the polarity of the applied gradient. The vulnerability of the stimulated echo-based PGSE sequence and variations of Hahn-based PGSE sequences is investigated. Both background gradients and radiation damping have serious implications for accurate diffusion measurement determination.

Emulsification of caraway essential oil in water by lecithin and beta-lactoglobulin: emulsion stability and properties of the formed oil-aqueous interface

The stability and droplet size of protein and lipid stabilised emulsions of caraway essential oil as well as the amount of protein on the emulsion droplets have been investigated. The amount of added protein (beta-lactoglobulin) and lipid (phosphatidylcholine from soybean (sb-PC)) were varied and the results compared with those obtained with emulsions of a purified olive oil. In general, emulsions with triglyceride oil proved to be more stable compared with those made with caraway essential oil as the dispersed phase. However, the stability of the emulsions can be improved considerably by adding sb-PC. An increase in the protein concentration also promoted emulsion stability. We will also present how ellipsometry can be used to study the adsorption of the lipid from the oil and the protein from the aqueous phase at the oil-water interface. Independently of the used concentration, close to monolayer coverage of sb-PC was observed at the caraway oil-aqueous interface. On the other hand, at the olive oil-aqueous interface, the presence of only a small amount of sb-PC lead to an exponential increase of the layer thickness with time beyond monolayer coverage. The amounts of beta-lactoglobulin adsorbed at the caraway oil-aqueous interface and at the olive oil-aqueous interface were similar, corresponding roughly to a protein monolayer coverage.