Secondary Organic Aerosol Formation from Urban Roadside Air in Hong Kong.

Motor vehicle emissions are an important but poorly constrained source of secondary organic aerosol (SOA). Here, we investigated in situ SOA formation from urban roadside air in Hong Kong during winter time using an oxidation flow reactor (OFR), with equivalent atmospheric oxidation ranging from several hours to several days. The campaign-average mass enhancement of OA, nitrate, sulfate, and ammonium upon OFR aging was 7.0, 7.2, 0.8, and 2.6 µg m-3, respectively. To investigate the sources of SOA formation potential, we performed multilinear regression analysis between measured peak SOA concentrations from OFR and the concentrations of toluene that represent motor vehicle emissions and cooking OA from positive matrix factorization (PMF) analysis of ambient OA. Traffic-related SOA precursors contributed 92.3%, 92.4%, and 83.1% to the total SOA formation potential during morning rush hours, noon and early afternoon, and evening meal time, respectively. The SOA production factor (PF) was approximately 5.2 times of primary OA (POA) emission factor (EF) and the secondary particulate matter (PM) PF was approximately 2.6 times of primary particles EF. This study highlights the potential benefit of reducing secondary PM production from motor vehicle emissions in mitigating PM pollutions.

Comparison of daytime and nighttime new particle growth at the HKUST supersite in Hong Kong.

Particles larger than 50-100 nm in diameter have been considered to be effective cloud condensation nuclei (CCN) under typical atmospheric conditions. We studied the growth of newly formed particles (NPs) in the atmosphere and the conditions for these particles to grow beyond 50 nm at a suburban coastal site in Hong Kong. Altogether, 17 new particle formation events each lasting over 1 h were observed in 17 days during 8 Mar-28 Apr and 1 Nov-30 Dec 2011. In 12 events, single-stage growth of NPs was observed in daytime when the median mobility diameter of NPs (Dp) increased up to ∼40 nm but did not increase further. In three events, two-stage particle growth to 61-97 nm was observed at nighttime. The second stage growth was preceded by a first-stage growth in daytime when the Dp reached 43 ± 4 nm. In all these 15 events, organics and sulfuric acid were major contributors to the first-stage growth in daytime. Ammonium nitrate unlikely contributed to the growth in daytime, but it was correlated with the second-stage growth of ∼40 nm NPs to CCN sizes at nighttime. The remaining two events apparently showed second-stage growth in late afternoon but were confirmed to be due to mixing of NPs with pre-existing particles. We conclude that daytime NP growth cannot reach CCN sizes at our site, but nighttime NP growth driven by organics and NH4NO3 can.

Analysis of organic sulfur compounds in atmospheric aerosols at the HKUST supersite in Hong Kong using HR-ToF-AMS.

Organic sulfur compounds have been identified in ambient secondary organic aerosols, but their contribution to organic mass is not well quantified. In this study, using a high-resolution time-of-flight aerosol mass spectrometer (AMS), concentrations of organic sulfur compounds were estimated based on the high-resolution fragmentation patterns of methanesulfonic acid (MSA), and organosulfates (OS), including alkyl, phenyl, and cycloalkyl sulfates, obtained in laboratory experiments. Mass concentrations of MSA and minimum mass concentrations of OS were determined in a field campaign conducted at a coastal site of Hong Kong in September 2011. MSA and OS together accounted for at least 5% of AMS detected organics. MSA is of marine origin with its formation dominated by local photochemical activities and enhanced by aqueous phase processing. OS concentrations are better correlated with particle liquid water content (LWC) than with particle acidity. High-molecular-weight OS were detected in the continental influenced period probably because they had grown into larger molecules during long-range transport or they were formed from large anthropogenic precursors. This study highlights the importance of both aqueous-phase processing and regional influence, i.e., different air mass origins, on organic sulfur compound formation in coastal cities like Hong Kong.

Economic aspects of sublingual immunotherapy.

Allergic rhinitis and asthma have a very high prevalence and constitute a health problem with a relevant burden of disease, concerning medical and economical issues. Among the treatments of allergy, specific immunotherapy (IT) has the capacity to favourably alter the natural history of the disease both during and after its performance, and thus to reduce the direct and indirect costs of allergic rhinitis and asthma. A number of studies reported a cost reduction for traditional, subcutaneous IT (SCIT). We analyzed the available studies on economic evaluation of sublingual immunotherapy (SLIT) in children and adults. Articles were retrieved from Medline and Embase using the terms economic aspects, pharmacoeconomics, cost effectiveness, and sublingual immunotherapy. 18 articles were found in English language, 7 studies investigated the economic advantage of SLIT over standard drug treatment in subjects with respiratory allergy, and 2 of them included a comparison of costs of SCIT and SLIT. The data obtained provide evidence that SLIT is associated to economic advantages and/or monetary savings, specifically in terms of reduction of economic burden of the disease. Although the number of studies is still limited, the available data support a SLIT effect on sparing costs for respiratory allergy.

[Budgetary impact of pneumococcal conjugate vaccination of newborns]. / Valutazione economica di una strategia di prevenzione delle infezioni da pneumococco sulla popolazione dei nuovi nati: una analisi di impatto di budget.

Pneumococcal (Pnc) disease represents a major healthcare concern being associated with severe complications. Scope of this study was to evaluate the budgetary impact effect of providing vaccination with seven-valent pneumococcal conjugate vaccine (PCV) to newborns in Lombardy (Italy). Budget impact analysis was applied to the 2004 cohort of newborns of Lombardy: efficacy data as number of pneumonia and acute otitis media (AOM) cases, and consumption of resources were derived from a large multicenter single-blind clinical study (results published) of vaccinated versus unvaccinated Italian children. Vaccinated children were administered 3 doses of PCV at 3, 5 and 11 months of age; Pnc morbidity was recorded until the 30th month of age. Economic analysis was performed in the perspective of the third party payer considering direct costs (vaccine doses, administration costs, drugs, visits and hospitalisations for management of Pnc disease complications); unit cost of resources (2006 values) was retrieved from national reimbursement tariff lists and other published sources. Our analysis suggests that the use of PCV in infants is likely to be economically justified due to savings from pneumonia and AOM cases averted, in the population of newborns of Lombardy.

Health technology assessment (HTA): definition, role and use in the changing healthcare environment.

The increasing availability of health care technology--boosted by considerable advances in areas like biotechnology, biomaterials, surgical techniques and computer technology--has accompanied burgeoning health care costs, and for this reason an increasing number of subjects (clinicians, health product makers, regulators, patients, hospitals, managers, payers, government leaders) demand for well-founded information to support decisions about development, adoption, acquisition and use of new and existing technologies. Technology assessment is a form of policy research that identifies policy issues, assesses the impact of alternative courses of action, and presents findings. This article is aimed at describing the historical development, reviewing the various definition and classifications, illustrating the purposes Fnd actors of Health Technology Assessment and its possible applications in the current healthcare scenario.

Pharmacoeconomics and immunotherapy.

Pharmacoeconomics is a relatively new discipline whose scope is to describe, measure and compare costs and outcomes of alternative healthcare programmes from a variety of perspectives. This article is aimed at describing the various types of pharmacoeconomics analyses, indicating what types of costs and outcomes could be measured within each type of study, summarising the value of modelling techniques in pharmacoeconomics studies and finally suggesting what kind of pharmacoeconomic research can usefully be conducted in order to appreciate the burden of respiratory allergic disease and to evaluate the economic impact of health technologies that can effectively be used to manage it. Pharmacoeconomics is a relatively recent discipline whose use has been spread by the necessity of decision makers in most industrialised countries, to gain understanding of the economic effect of medical technologies in parallel with their clinical performance: only a wider use of the techniques of pharmacoeconomics analysis, together with an increasing willingness of the scientific community to understand the mechanics and appreciate the added value of pharmacoeconomics analysis, can help the discipline to proceed and provide further improvement to the healthcare system and to the society.

Cost effectiveness of sublingual immunotherapy in children with allergic rhinitis and asthma.

BACKGROUND: Economic evaluations are increasingly relevant in order to provide support for decision makers when judging about alternative ways to allocate public funds. Aim of this study was to evaluate the economic effect of treatment with high dose sublingual immunotherapy (SLIT) in children. METHODS: The study involved one allergy center, located in the north of Milan, Italy. From the existing records of patients seen for allergic disease, we extracted all children and adolescents with allergic disease, who had 1-year data prior to receiving SLIT and 3-year data on SLIT. Outcome measures (number of exacerbations, visits, absence from nursery or school), direct costs (euros spent on drugs, specialist visits, SLIT) and indirect costs (costs resulting from children school and parental work loss) were analysed. A second analysis compared a sub-group of allergic asthmatic children with a control group for costs, based on records of patients not SLIT-treated, extracted from a network-database of paediatricians. RESULTS: 135 patients were extracted, of which 46 had perennial, and 89 had seasonal allergy with comparable gender and age distribution. A substantial reduction was found in all outcome measures during SLIT compared with the before period. The average annual cost/patient was 2672 before SLIT initiation and _629/year during SLIT. Similar results were found for allergen subgroups. The asthma sub-analysis involved 41 children with SLIT and 35 controls. Again, SLIT patients showed a substantial reduction in outcome measures; the direct cost/patient over the whole follow-up (4 years) was _1182 for SLIT patients and _1100 for controls. CONCLUSION: High dose SLIT may be effective in reducing the cost of allergic rhinitis and asthma and comparably expensive to conventional treatment in children with allergic asthma over a 4 years follow-up.

Cost-of-illness of lung disease in the TriVeneto Region, Italy: the GOLD Study.

Lung diseases imply a high consumption of healthcare resources representing a burden for patients and their families as well as for the society. The aim of the Global Outcomes in Lung Diseases (GOLD) study was to perform a cost-of-illness analysis of three pathologies affecting the lower respiratory tract: community-acquired pneumonia (CAP), chronic obstructive pulmonary disease (COPD) and bronchial asthma (BA). This observational study was conducted in a large region of northeast Italy, Triveneto, between 1999 and 2000. Patients of both sexes and aged > or = 14 years, were randomly selected from 28 identified centres of pneumology; patients were considered eligible if they had been visited at least twice at the centre during the observational period. Study periods were different for the three pathologies: for BA and COPD the recruitment period lasted 8 weeks and the follow-up period 12 months; for CAP, given the acute nature of the disease, two recruitment periods (May and November) were identified with a follow-up lasting 6 months. After collecting information for each patient (age, sex, risk factors, severity of the disease, occupation), data were recorded by each centre in a dedicated software program and then sent to a central database where final results were analysed. Cost-of-illness analysis was conducted within the framework of the National Healthcare System (NHS). Consumption of medical resources used during the follow-up period was valued according to market prices and published official tariffs. A total number of 1068 patients (596 men and 458 women) were selected: 42.5% were affected by BA, 46.3% by COPD, and 11.2% by CAP. Mean cost per patient/year for patients affected by BA and COPD ranged from Euro 608 to 2457 and from Euro 1500 to 3912, respectively, depending on illness severity. Mean cost per episode of CAP was Euro 1586. This study confirms the findings of other studies published in the international literature, demonstrating that asthma and COPD are often misdiagnosed and mistreated and so their management, especially for the most severe patients, becomes complex and highly expensive. The use of preventive, specialised care could help in achieving early diagnosis and treatment of these patients.

The epidemiology, economics and quality of life burden of age-related macular degeneration in France, Germany, Italy and the United Kingdom.

Age-related macular degeneration (AMD) is a major public health issue, but little is known about the economics of the disease. This contribution describes the epidemiology and the economics of AMD in four European countries: France, Germany, Italy and the United Kingdom (UK). We reviewed published information on AMD, including guidelines, official statistics, and local literature and interviewed AMD experts. All available health-related quality of life studies (HRQoL) on AMD were also reviewed. Data collection focused on epidemiology, medical management and resource use (both medical and non-medical items). Prevalence of AMD among persons older than 65 years is 8% and increases with age. There are two forms of the disease: atrophic (80-85% of AMD cases) and exudative, which is characterised by choroidal neovascularisation (CNV; 15-20% of AMD cases). No treatment for the atrophic form is available. Laser photocoagulation is the mainstay of treatment for CNV, although less than 30% of persons with CNV can benefit from it. Photodynamic therapy (PDT), a new treatment for CNV, reduces the risk of vision loss in forms with predominantly visible lesions. Several other new procedures are also under development. Rehabilitation and low-vision aids are useful palliative interventions when there is a residual visual acuity. The yearly budget impact of AMD was found to be between 51.3 and 101.1 million euros in the four countries studied. Information on social services and resource use was scant and little is reported on the impact of AMD on HRQoL. Economic studies of AMD should be conducted in order to assist public health decision making.

The PANDORA project: results of the cost of illness analysis.

AIMS: To evaluate the cost of illness from hypertension for the Italian National Health System (NHS). METHODS AND RESULTS: A prospective analysis was carried out on clinical and economic data recorded in the general practitioners' (GPs) database. Twenty-one GPs working in the Ravenna area in Italy took part in the project on a voluntary basis. The study included 1047 hypertensive patients enrolled between 1 June and 31 December 1997 and continued for 365 days from the date of enrolment. The following costs were calculated: antihypertensive drugs, laboratory tests and instrumental procedures, GP visits for blood pressure control, specialist visits, casualty visits, hospitalisation due to cardiovascular problems. In the whole sample, the most relevant cost is due to antihypertensive drugs (42.7%), followed by hospital admission (28.4%), GP visits (15.1%) and tests (10.6%). The total mean cost was significantly lower in incident (no previous treatment) than in prevalent patients (already treated) (457 512 vs 725 573 Italian Lira (ITL), P < 0.05) and in older rather than in younger patients (1171 410 vs 796 452 (ITL) P < 0.05). (In the text the equivalent is given in Euros, Pounds Sterling and US dollars). CONCLUSION: Our study should be considered as preliminary, nevertheless it could represent a step towards the evaluation of the true cost of hypertension.

Possible Role of Colonization and Cell Wall-Degrading Enzymes in the Differential Ability of Three Ulocladium atrum Strains to Control Botrytis cinerea on Necrotic Strawberry Leaves.

ABSTRACT Ulocladium atrum (strain 385) consistently reduced Botrytis cinerea sporulation on necrotic fragments of strawberry leaves. On these tissues, two strains of U. atrum (isolates 18558 and 18559) showed lower antagonistic activities than the reference strain 385. Colonization of strawberry leaflets by the three U. atrum strains appeared similar in the absence of B. cinerea, whether quantified by chitin or immunological assays. The second method (based on anti-U. atrum antibodies) revealed that strawberry leaflet colonization by U. atrum 385 was better than by the other U. atrum strains in the presence of B. cinerea. An immunoassay using anti-B. cinerea antibodies revealed that the colonization of B. cinerea in tissues was lower in the presence of U. atrum 385 than with the two other U. atrum strains. The enzymatic activities produced by U. atrum 385 during the colonization phases of necrotic tissues were compared to B. cinerea and U. atrum strains 18558 and 18559. U. atrum 385 had the highest lipase, pectate lyase, and cellobiase activities while B. cinerea had the highest endo-beta-1,4-glucanase activity. The study of lytic activities hydrolyzing the fungal cell wall revealed higher beta-1,3-glucanase activity with U. atrum 385, which was stimulated by B. cinerea on necrotic strawberry leaflets. These results suggest that plant and fungal cell wall-degrading enzymes produced by U. atrum 385 may play a complementary role in the competitive colonization of dead strawberry leaves against B. cinerea.

Cost-of-illness of epilepsy in Italy. Data from a multicentre observational study (Episcreen).

OBJECTIVE: To investigate the impact of epilepsy in Italy on healthcare resources, producing an average cost per patient per year of follow-up. DESIGN AND SETTING: The Episcreen Project is a multicentre longitudinal Italian observational study; its methodology, organisational network and case report form have been reported in detail elsewhere. Using a subset of patients with epilepsy from this project, we conducted a retrospective cost-of-illness analysis based on clinical records. The analysis was performed from the societal (community) perspective, including both direct and indirect costs. Hospital admissions, day-hospital visits, specialist visits, instrumental examinations, drugs and productivity losses because of visits and hospitalisation were analysed. Each cost variable was valued in 1996 Italian liras (L) using published national tariffs (except for drugs for which published prices were used). A sensitivity analysis was conducted on indirect costs to test the robustness of the assumption that 1 working day lost for each day hospital visit would produce a change of 0.3% in the weight of indirect costs. PATIENTS AND PARTICIPANTS: Patients analysed in this study were registered in the Episcreen database as at 21 November 1996. They were diagnosed with epilepsy at the last visit, had at least 1 follow-up visit (i.e. at least 1 visit after the enrolment visit), and had at least 12 months of follow-up. RESULTS: The average cost per patient per year was L2,726,116 ($US1767). The average cost per patient was higher for children than for adults [L3,629,997 ($US2353) and L2,362,134 ($US1531), respectively), and for newly diagnosed patients for whom the first diagnosis of epilepsy was addressed at the first Episcreen visit [adults: old referrals L1,304,353 ($US845), new referrals L6,901,374 ($US4473); children: old referrals L2,810,504 ($US1822), new referrals L7,814,400 ($US5065)]. Direct costs represented 87.6% of total costs. The major cost driver was hospitalisation (63.7%), followed by drugs (10.5%), day-hospital visits (4.1%), out-patient visits (3.85%), other tests (3.1%) and electroencephalographs (2.3%). Indirect costs (lost productivity) represented 12.4% of total costs. Sensitivity analysis showed that the results are sensitive to the value attributed to lost productivity. CONCLUSIONS: The cost of managing a patient with epilepsy in Italy is influenced by age, syndrome and modality of referral to the centre for epilepsy.

Cost-effectiveness analysis for statin therapies in the primary prevention of coronary heart disease in Italy.

OBJECTIVE: The objective of this analysis was to compare the costs, benefits and cost effectiveness of two dosage regimens of cerivastatin (0.2 and 0.4 mg/day) with Italian National Health Service (NHS) reimbursed comparative statins in the primary prevention of coronary heart disease in Italy. This study is part of a broader analysis undertaken in five European countries. DESIGN AND SETTING: A cost-effectiveness analysis (CEA) was performed, as the interventions have the same treatment objectives but vary in terms of magnitude of effectiveness. This CEA compared alternative treatments both in the NHS and from societal perspectives. PATIENTS: A coronary heart disease risk assessment model, based on intervention study data from the Lipid Research Clinics Coronary Primary Prevention Trial, was used. This was augmented with demographic, disease, life expectancy, pharmacological and economic data for patients with coronary heart disease in Italy. RESULTS: In terms of average cost effectiveness, our analysis showed that cerivastatin 0.2 mg/day compared favourably with pravastatin 20 mg/day, and compared similarly with simvastatin 20 mg/day in all age groups studied. The study also demonstrated that cerivastatin 0.4 mg/day compared favourably with both simvastatin 40 mg/day and pravastatin 20 mg/day. These results were consistent for both the NHS and societal perspective.The incremental cost per life-year gained [in 1998 Italian lire (L)] of simvastatin versus cerivastatin ranged from about L40 million [or Euro (Eur)20 658] to greater than L650 million (or Eur335 697). Cerivastatin 0.2 mg/day was more cost-effective than pravastatin 20 mg/day, while the incremental cost per life-year gained for cerivastatin 0.4 mg/day versus pravastatin 20 mg/day ranged from L11.1 million (or Eur5733) to L31.8 million (or Eur16 423) in the three age groups (35 to 39 years, 50 to 54 years and 65 to 69 years) for both perspectives. CONCLUSIONS: The results of this study showed that in primary prevention, average cost-effectiveness ratios of cerivastatin compared favourably with those of the other pharmacological interventions available on the Italian market.

Occurrence of a lipase in spores of Alternaria brassicicola with a crucial role in the infection of cauliflower leaves.

Alternaria brassicicola is a pathogen that penetrates directly through the host cuticle thanks to several serine esterases, according to our findings. Among these, an 80-kDa lipase (E.C 3.1.1. 3) was detected by SDS-PAGE and immunoblotting in the water washings of ungerminated spores. The purified lipase cross-reacted with Botrytis cinerea anti-lipase antibodies, which were reported to inhibit the in vitro lipase activity. Anti-lipase antibodies were added to a conidial suspension of A. brassicicola prior to inoculation. As a result, blackspot lesions were reduced by 90% on intact cauliflower leaves, but not on leaves from which surface wax had been removed. Spore surface-bound lipase is thought to interact closely with epicuticular leaf waxes for adhesion and/or penetration of the fungal propagules during the early stages of host-parasite interactions.

The Pandora Project: results of the pilot study.

The Pandora Project was designed to develop a computer-assisted system to improve the appropriateness and effectiveness of hypertension treatment in clinical practice and to organize a database both for epidemiologic and economic assessments. The feasibility study was conducted by five general practitioners (GP) who enrolled 244 patients over a period of 6 months. The follow-up lasted 6 months. The computer system implemented provided a linkage among GP's office, hypertension unit, Ravenna Health Service databases, and a remote station. A total of 209 patients completed the follow-up period; 56% of patients were not normotensive despite the antihypertensive treatment. The prevalence of overweight, physical inactivity, and family history of high blood pressure and hypercholesterolemia was greater than 50%. Unplanned check-ups by GP occurred 9%. Six patients were admitted to the hospital eight times; 19 patients attended the casualty department 21 times. The mean total direct cost per patient was 567,800 Italian Lire (ITL) and increased to ITL 732,000 or to ITL 825,900 when lost productivity, calculated according to two different formulas, was added. This pilot study confirms the need and feasibility of implementing the Pandora Project in general practice in Ravenna.

A multinational investigation of the impact of subcutaneous sumatriptan. I: Design, methods and clinical findings.

This report describes the design, methods and clinical results of a prospective sequential multinational (5 countries) study conducted to evaluate the effects of subcutaneous sumatriptan on health-related quality of life, workplace productivity, clinical parameters and patient satisfaction. Adult patients with moderate to severe migraine initially received customary therapy for migraine episodes for 12 weeks, followed by 24 weeks' treatment with self-administered subcutaneous sumatriptan 6 mg. Demographic, baseline, health-related quality of life and patient satisfaction rating data were collected during visits to the clinic. Data relating to migraine symptoms, migraine therapy, work productivity and non-work activity time were collected on diary cards filled out by the patients. 749 patients were recruited to the study and 637 received at least 1 dose of sumatriptan. Overall, 75.5% of migraines were successfully treated within 2 hours with sumatriptan compared with 31.9% with customary therapy; 36% of patients reported complete relief at 2 hours with sumatriptan treatment compared with 1% of patients receiving customary therapy. 69% of patients successfully treated 70% of their migraines with sumatriptan within 2 hours, compared with 12% of patients with customary therapy. No serious adverse events were reported; 50% of patients reported an adverse event during the 12-week customary therapy phase and 89% of patients during the 24-week sumatriptan phase. These clinical results, which are consistent with those reported in randomised blinded studies of subcutaneous sumatriptan, suggest that relief of migraine symptoms occurs more often, and in less time, in patients receiving subcutaneous sumatriptan rather than customary therapy as their primary medication.

Cost and cost-effectiveness analysis of ondansetron versus metoclopramide regimens: a hospital perspective from Italy.

In a large double-blind study of antiemetic therapy conducted in Italy, 289 patients underwent 3 consecutive cycles of cisplatin chemotherapy. Antiemetic treatment with ondansetron plus dexamethasone was more efficacious and better tolerated, but also more expensive, than treatment with metoclopramide plus both dexamethasone and diphenhydramine. To evaluate the different costs of the 2 antiemetic regimens, we conducted a retrospective cost-effectiveness analysis from a hospital perspective. Direct costs of antiemetic therapy (acquisition cost of drugs, materials and time spent by nurses to prepare and administer therapies), cleanup after emesis, rescue medication and adverse events were evaluated. Antiemetic drug acquisition costs per patient were 5.23-fold higher for the ondansetron regimen than for the metoclopramide regimen. However, when the costs of materials and nursing time required to prepare and administer the antiemetic regimens were included, this ratio was 3.77. Furthermore, including the cost of emesis, rescue antiemetic treatments and medication used to treat adverse events, hospital costs per patient were 3.21-fold higher with the ondansetron regimen during the first cycle, 3.08-fold higher during second cycle and 2.89-fold higher during third cycle of chemotherapy. Complete protection from vomiting and from both vomiting and nausea with ondansetron occurred, respectively, in 78.7 and 69.1% of patients in the first cycle, 73.8 and 57.3% in the second cycle, and 74.2 and 58.1% in third cycle of chemotherapy. Corresponding figures for the metoclopramide regimen were 59.5 and 50.4%, 53.6 and 37.1%, and 46.8 and 27.3%, respectively. Thus, the cost per successfully treated (completely protected) patient was 2.43- and 2.34-fold higher, respectively, for ondansetron at the first cycle, 2.23- and 1.99-fold higher, respectively, at second cycle, and 1.82- and 1.36-fold higher, respectively, at third cycle. In conclusion, the study demonstrates that, while ondansetron has a greater acquisition cost than metoclopramide, the ondansetron regimen costs per successfully-treated patient substantially decrease when all direct hospital costs are taken into account.

A new scintigraphic method to characterize ultrafiltration in hollow fiber dialyzers.

Ultrafiltration and pressure profiles in hollow fiber dialyzers with different hydraulic permeabilities have been investigated with a new scintigraphic method. Radiolabelled albumin macroaggregates, used as a nondiffusible marker molecule, were added to the blood in an in vitro circuit and circulated through cuprophan and polysulphon dialyzers. Since the marker molecule was too big to cross the dialysis membrane, its changes in concentration were assumed to occur in response to the variation of the blood water content (filtration or back-filtration). These changes in concentration, recorded by a gamma camera, were evaluated to establish the cumulative values of filtration and back-filtration and their relevant profiles along the length of the dialyzer. The achieved data were compared with the experimental values of ultrafiltration empirically measured and with the theoretical values predicted by a classic linear method. Two conditions were analyzed: A) the minimal filtration rate necessary to avoid back-filtration (critical filtration); and B) the condition of zero net filtration in which filtration equals back-filtration. The nuclear method proved to be extremely precise in predicting the ultrafiltration values and significantly more precise than the linear method, especially for the highly permeable dialyzer. The reason for that probably depends on the non-linear pressure and ultrafiltration profile observed with the scintigraphic pattern of the dialyzer. Viscosity changes and local variations in blood flow may in fact interfere with the pressure drop inside the hollow fibers and result in such a complex behavior. The other interesting aspect of this method is the possibility of accurate measurement of the amount of back-filtration that wouldn't be possible with simple calculations. In conclusion, the complex nature of the phenomena regulating the water fluxes in hollow fiber dialyzers requires more complex calculation than a simple linear model to achieve an accurate range of predictability.