A regional Industrial Symbiosis methodology and its implementation in Geneva, Switzerland

The Agenda 21 for the Geneva region is the results from a broad consultation process including all local actors. The article 12 stipulates that « the State facilitates possible synergies between economic activities in order to minimize their environmental impacts » thus opening the way for Industrial Ecology (IE) and Industrial Symbiosis (IS). An Advisory Board for Industrial Ecology and Industrial Symbiosis implementation was established in 2002 involving relevant government agencies. Regulatory and technical conditions for IS are studied in the Swiss context. Results reveal that the Swiss law on waste does not hinder by-product exchanges. Methodology and technical factors including geographic, qualitative, quantitative and economical aspects are detailed. The competition with waste operators in a highly developed recycling system is also tackled.The IS project develops an empirical and systematic method for detecting and implementing by-products synergies between industrial actors disseminated throughout the Geneva region. Database management tool for the treatment of input-output analysis data and GIS tools for detecting potentials industrial partners are constantly improved. Potential symbioses for 17 flows (including energy, water and material flows) are currently studied for implementation.

Beliefs and practices in the assessment of workplace pollutants

OBJECTIVES: A survey was undertaken among Swiss occupational hygienists and other professionals to identify the different exposure assessment methods used, the contextual parameters observed and the uses, difficulties and possible developments of exposure models for field application. METHODS: A questionnaire was mailed to 121 occupational hygienists, all members of the Swiss Occupational Hygiene Society. A shorter questionnaire was also sent to registered occupational physicians and selected safety specialists. Descriptive statistics and multivariate analyses were performed. RESULTS: The response rate for occupational hygienists was 60%. The so-called expert judgement appeared to be the most widely used method, but its efficiency and reliability were both judged with very low scores. Long-term sampling was perceived as the most efficient and reliable method. Various determinants of exposure, such as emission rate and work activity, were often considered important, even though they were not included in the exposure assessment processes. Near field local phenomena determinants were also judged important for operator exposure estimation. CONCLUSION: Exposure models should be improved to integrate factors which are more easily accessible to practitioners. Descriptors of emission and local phenomena should also be included.

A highly sensitive LC-tandem MS assay for the measurement in plasma and in urine of salbutamol administered by nebulization during mechanical ventilation in healthy volunteers.

The new-generation nebulizers are commonly used for the administration of salbutamol in mechanically ventilated patients. The different modes of administration and new devices have not been compared. We developed a liquid chromatography-tandem mass spectrometry method for the determination of concentrations as low as 0.05 ng/mL of salbutamol, corresponding to the desired plasma concentration after inhalation. Salbutamol quantification was performed by reverse-phase HPLC. Analyte quantification was performed by electrospray ionization-triple quadrupole mass spectrometry using selected reaction monitoring detection ESI in the positive mode. The method was validated over concentrations ranging from 0.05 to 100 ng/mL in plasma and from 0.18 to 135 ng/mL in urine. The method is precise, with mean inter-day coefficient of variation (CV%) within 3.1-8.3% in plasma and 1.3-3.9% in urine, as well as accurate. The proposed method was found to reach the required sensitivity for the evaluation of different nebulizers as well as nebulization modes. The present assay was applied to examine whether salbutamol urine levels, normalized with the creatinine levels, correlated with the plasma concentrations. A suitable, convenient and noninvasive method of monitoring patients receiving salbutamol by mechanical ventilation could be implemented. Copyright © 2011 John Wiley & Sons, Ltd.

Sensitive determination of D-lactic acid and L-lactic acid in urine by high-performance liquid chromatography-tandem mass spectrometry.

D-lactic acid in urine originates mainly from bacterial production in the intestinal tract. Increased D-lactate excretion as observed in patients affected by short bowel syndrome or necrotizing enterocolitis reflects D-lactic overproduction. Therefore, there is a need for a reliable and sensitive method able to detect D-lactic acid even at subclinical elevation levels. A new and highly sensitive method for the simultaneous determination of L- and D-lactic acid by a two-step procedure has been developed. This method is based on the concentration of lactic acid enantiomers from urine by supported liquid extraction followed by high-performance liquid chromatography-tandem mass spectrometry. The separation was achieved by the use of an Astec Chirobiotic? R chiral column under isocratic conditions. The calibration curves were linear over the ranges of 2-400 and 0.5-100 µmol/L respectively for L- and D-lactic acid. The limit of detection of D-lactic acid was 0.125 µmol/L and its limit of quantification was 0.5 µmol/L. The overall accuracy and precision were well within 10% of the nominal values. The developed method is suitable for production of reference values in children and could be applied for accurate routine analysis.

Identifying a mutual attending frame: a pilot study of gaze interactions between therapist and couple.

Refering to systems theory, we identify a supraindividual property in interactions between therapist and couple. We use gaze directions to describe the partners' behaviors and label this property the "mutual attending frame." We propose a procedure to observe triadic interactions in a consultation setting and a method to measure mutual attending. The method is illustrated by the data analysis of two triads contrasted on measures of therapeutic alliance. We discuss the potential of this method for the description of the interactive aspects of the therapeutic alliance.

In vitro activity of gallium maltolate against Staphylococci in logarithmic, stationary, and biofilm growth phases: comparison of conventional and calorimetric susceptibility testing methods.

Ga(3+) is a semimetal element that competes for the iron-binding sites of transporters and enzymes. We investigated the activity of gallium maltolate (GaM), an organic gallium salt with high solubility, against laboratory and clinical strains of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), methicillin-susceptible Staphylococcus epidermidis (MSSE), and methicillin-resistant S. epidermidis (MRSE) in logarithmic or stationary phase and in biofilms. The MICs of GaM were higher for S. aureus (375 to 2000 microg/ml) than S. epidermidis (94 to 200 microg/ml). Minimal biofilm inhibitory concentrations were 3,000 to >or=6,000 microg/ml (S. aureus) and 94 to 3,000 microg/ml (S. epidermidis). In time-kill studies, GaM exhibited a slow and dose-dependent killing, with maximal action at 24 h against S. aureus of 1.9 log(10) CFU/ml (MSSA) and 3.3 log(10) CFU/ml (MRSA) at 3x MIC and 2.9 log(10) CFU/ml (MSSE) and 4.0 log(10) CFU/ml (MRSE) against S. epidermidis at 10x MIC. In calorimetric studies, growth-related heat production was inhibited by GaM at subinhibitory concentrations; and the minimal heat inhibition concentrations were 188 to 4,500 microg/ml (MSSA), 94 to 1,500 microg/ml (MRSA), and 94 to 375 microg/ml (MSSE and MRSE), which correlated well with the MICs. Thus, calorimetry was a fast, accurate, and simple method useful for investigation of antimicrobial activity at subinhibitory concentrations. In conclusion, GaM exhibited activity against staphylococci in different growth phases, including in stationary phase and biofilms, but high concentrations were required. These data support the potential topical use of GaM, including its use for the treatment of wound infections, MRSA decolonization, and coating of implants.

Robust parametric indirect estimates of the expected cost of a hospital stay with covariates and censored data.

We consider the problem of estimating the mean hospital cost of stays of a class of patients (e.g., a diagnosis-related group) as a function of patient characteristics. The statistical analysis is complicated by the asymmetry of the cost distribution, the possibility of censoring on the cost variable, and the occurrence of outliers. These problems have often been treated separately in the literature, and a method offering a joint solution to all of them is still missing. Indirect procedures have been proposed, combining an estimate of the duration distribution with an estimate of the conditional cost for a given duration. We propose a parametric version of this approach, allowing for asymmetry and censoring in the cost distribution and providing a mean cost estimator that is robust in the presence of extreme values. In addition, the new method takes covariate information into account.

Simultaneous determination of human plasma levels of citalopram, paroxetine, sertraline, and their metabolites by gas chromatography-mass spectrometry.

A gas chromatography-mass spectrometry method is presented which allows the simultaneous determination of the plasma concentrations of the selective serotonin reuptake inhibitors citalopram, paroxetine, sertraline, and their pharmacologically active N-demethylated metabolites (desmethylcitalopram, didesmethylcitalopram, and desmethylsertraline) after derivatization with the reagent N-methyl-bis(trifluoroacetamide). No interferences from endogenous compounds are observed following the extraction of plasma samples from six different human subjects. The standard curves are linear over a working range of 10-500 ng/mL for citalopram, 10-300 ng/mL for desmethylcitalopram, 5-60 ng/mL for didesmethylcitalopram, 20-400 ng/mL for sertraline and desmethylsertraline, and 10-200 ng/mL for paroxetine. Recoveries measured at three concentrations range from 81 to 118% for the tertiary amines (citalopram and the internal standard methylmaprotiline), 73 to 95% for the secondary amines (desmethylcitalopram, paroxetine and sertraline), and 39 to 66% for the primary amines (didesmethylcitalopram and desmethylsertraline). Intra- and interday coefficients of variation determined at three concentrations range from 3 to 11% for citalopram and its metabolites, 4 to 15% for paroxetine, and 5 to 13% for sertraline and desmethylsertraline. The limits of quantitation of the method are 2 ng/mL for citalopram and paroxetine, 1 ng/mL for sertraline, and 0.5 ng/mL for desmethylcitalopram, didesmethylcitalopram, and desmethylsertraline. No interferences are noted from 20 other psychotropic drugs. This sensitive and specific method can be used for single-dose pharmacokinetics. It is also useful for therapeutic drug monitoring of these three drugs and could possibly be adapted for the quantitation of the two other selective serotonin reuptake inhibitors on the market, namely fluoxetine and fluvoxamine.

Evaluation of respiratory and dermal occupational exposures to monoethanolamine during cleaning

Professional cleaning is a basic service occupation with a wide variety of tasks carried out in all kind of different sectors and workplaces by a large workforce. One important risk for cleaning workers is the exposure to chemical substances that are present in cleaning products.Monoethanolamine was found to be often present in cleaning products such as general purpose cleaners, bathroom cleaners, floor cleaners and kitchen cleaners. Monoethanolamine can injure the skin, and exposure to monoethanolamine was associated to asthma even when the air concentrations were low. It is a strong irritant and known to be involved in sensitizing mechanisms. It is very likely that the use of cleaning products containing monoethanolamine gives rise to respiratory and dermal exposures. Therefore there is a need to further investigate the exposures to monoethanolamine for both, respiratory and dermal exposure.The determination of monoethanolamine has traditionally been difficult and analytical methods available are little adapted for occupational exposure assessments. For monoethanolamine air concentrations, a sampling and analytical method was already available and could be used. However, a method to analyses samples for skin exposure assessments as well as samples of skin permeation experiments was missing. Therefore one main objective of this master thesis was to search an already developed and described analytical method for the measurement of monoethanolamine in water solutions, and to set it up in the laboratory. Monoethanolamine was analyzed after a derivatisation reaction with o-pthtaldialdehyde. The derivated fluorescing monoethanolamine was then separated with high performance liquid chromatography and detection took place with a fluorescent detector. The method was found to be suitable for qualitative and quantitative analysis of monoethanolamine. An exposure assessment was conducted in the cleaning sector to measure the respiratory and dermal exposures to monoethanolamine during floor cleaning. Stationary air samples (n=36) were collected in 8 companies and samples for dermal exposures (n=12) were collected in two companies. Air concentrations (Mean = 0.18 mg/m3, Standard Deviation = 0.23 mg/m3, geometric Mean = 0.09 mg/m3, Geometric Standard Deviation = 3.50) detected were mostly below 1/10 of the Swiss 8h time weighted average occupational exposure limit. Factors that influenced the measured monoethanolamine air concentrations were room size, ventilation system and the concentration of monoethanolamine in the cleaning product and amount of monoethanolamine used. Measured skin exposures ranged from 0.6 to 128.4 mg/sample. Some cleaning workers that participated in the skin exposure assessment did not use gloves and had direct contact with the solutions containing the cleaning product and monoethanolamine. During the entire sampling campaign, cleaning workers mostly did not use gloves. Cleaning workers are at risk to be regularly exposed to low air concentrations of monoethanolamine. This exposure may be problematic if a worker suffers from allergic reactions (e.g. Asthma). In that case a substitution of the cleaning product may be a good prevention measure as several different cleaning products are available for similar cleaning tasks. Currently there are no occupational exposure limits to compare the skin exposures that were found. To prevent skin exposures, adaptations of the cleaning techniques and the use of gloves should be considered. The simultaneous skin and airborne exposures might accelerate adverse health effects. Overall the risks caused by exposures to monoethanolamine are considered as low to moderate when the cleaning products are used correctly. Whenever possible, skin exposures should be avoided. Further research should consider especially the dermal exposure routes, as very high exposures might occur by skin contact with cleaning products. Dermatitis but also sensitization might be caused by skin exposures. In addition, new biomedical insights are needed to better understand the risks of the dermal exposure. Therefore skin permeability experiments should be considered.

New drugs and combinations for malignant glioma.

A new chemotherapy agent and a method for local delivery of carmustine have recently been approved for the treatment of malignant glioma. However, the increase in survival remains modest at best with only a very select patients currently benefiting truly of these treatments. Combination regimen of different alkylating agents or prior O6-alkyltransferase depletion by O6-benzylguanine or continuous temozolomide administration schedules have shown some indication for increased activity. There is preclinical rational for combining temozolomide with radiotherapy and the initial results of a phase II clinical trial were promising. Several new cytotoxic agents are currently in clinical trials in patients with recurrent glioma. More importantly, targeted therapy and antiangiogenic agents have entered the clinical development phase also for patients with glioblastoma and anaplastic astrocytoma. The optimal timing of administration of non-cytotoxic substances and their integration into the currently available treatments remains a challenge. Novel study designs and identification of surrogate markers are necessary in order to make rapid and clinically meaningful progress. This review summarises the currently available evidence of activity of the recently approved drugs against malignant glioma and mentions also agents which have failed to demonstrate a significant antitumour activity. Study endpoints are critically discussed. Combination regimens with other agents and radiation therapy are reviewed. The rational for using antiangiogenic drugs in selected ongoing trials is discussed.

Measuring discrepancies between knowledge, preoccupation and fear of aids in populations.

A simple tool to quantify discrepancies between knowledge, preoccupation and fear regarding hiv and aids is presented. This tool is based on standard questions available in health surveys. Some results using recent Swiss data are presented, and the method is discussed.

Natural aphrodisiacs: studies of commercially-available herbal recipes, and phytochemical investigation of "Erythroxylum vacciniifolium" Mart. (Erythroxylaceae) from Brazil

De tout temps, hommes et femmes ont cherché par tous les moyens à développer, préserver ou recouvrer leurs propres capacités sexuelles mais également à stimuler le désir du partenaire. L?utilisation d?aphrodisiaques naturels a été l?un des recours les plus répandus. De nos jours, la commercialisation de nouvelles "love drugs" de synthèse, e.g. Viagra®, Cialis®, Levitra®, a remis au goût du jour les aphrodisiaques classiques et à relancer la recherche sur des molécules nouvelles. La pratique croissante de l?automédication, le matraquage publicitaire sur les aphrodisiaques naturels, la prolifération sur le marché de compléments alimentaires non contrôlés et l?absence de véritable législation accroissent les risques qui pèsent sur la santé publique. Dans le but d?évaluer les risques potentiels sur le consommateur de produits aphrodisiaques commercialisés, le développement et la validation d?une méthode rapide d?analyse qualitative et quantitative de la yohimbine dans ces préparations du marché sont exposés dans la première partie de ce travail. La yohimbine est un antagoniste ?2-adrénocepteur du système nerveux central et périphérique, elle est employée depuis plus d?un siècle dans le traitement des dysfonctionnements érectiles. Cette méthode analytique utilise la chromatographie liquide couplée à l?ultraviolet et à la spectrométrie de masse (LC-UV-MS) et au total, vingt préparations aphrodisiaques ont été étudiées. La dose journalière de yohimbine mesurée s?est révélée très variable selon les produits puisqu?elle varie de 1.32 à 23.16 mg. La seconde partie de ce travail concerne l?étude phytochimique et pharmacologique d?Erythroxylum vacciniifolium Mart. (Erythroxylaceae), une plante, appelée localement catuaba, utilisée dans la médecine traditionnelle brésilienne comme tonique et aphrodisiaque. Dans un premier temps, l?extrait alcaloïdique a été analysé par chromatographie liquide haute performance (HPLC) couplée soit à un détecteur UV à barrette d?iode (LC-UV-DAD), soit à un spectromètre de masse (LC-MS), ou soit à un spectromètre de résonance magnétique nucléaire (LC-RMN). L?interprétation de ces données spectrales enregistrées en ligne a permis d?obtenir des informations structurales et d?identifier partiellement près de 24 alcaloïdes appartenant à la classe des tropanes et potentiellement originaux. Par des méthodes classiques de chromatographie liquide sur l?extrait alcaloïdique de la plante, dix sept tropanes nouveaux ont ensuite été isolés dont les catuabines et leurs dérivés, et les vaccinines. Tous ces composés sont des tropane-diols ou triols estérifiés par au moins un groupe acide 1-méthyl-1H-pyrrole-2-carboxylique. Un de ces composés a été identifié comme un tropane N-oxyde. Toutes les structures ont été déterminées par spectrométrie de masse haute résolution et spectroscopie RMN multi-dimensionnelle. Parmi les nombreux tests biologiques réalisés sur ces tropanes, seuls les tests de cytotoxicité se sont révélés faiblement positifs pour certains de ces composés.<br/><br/>Throughout the ages, men and women have incessantly pursued every means to increase, preserve or recapture their sexual capacity, or to stimulate the sexual desire of selected individuals. One of the most recurrent methods has been the use of natural aphrodisiacs. Nowadays, the commercialization of new synthetic "love drugs", e.g. Viagra®, Cialis® and Levitra®, has fascinated the public interest and has led to a reassessment of classical aphrodisiacs and to the search for new ones. The practice of self-medication by an increasing number of patients, the incessant aggressive advertising of these herbal aphrodisiacs, the invasion of the medicinal market with uncontrolled dietary supplements and the absence of real directives amplifies the potential health hazards to the community. In order to evaluate the possible risks of commercialized aphrodisiac products on consumer health, the development and validation of a rapid qualitative and quantitative method for the analysis of yohimbine in these products, is reported in the first part of the present work. Yohimbine, a pharmacologically well-characterized ?2-adrenoceptor antagonist with activity in the central and peripheral nervous system, has been used for over a century in the treatment of erectile dysfunction. The analytical method is based on liquid chromatography coupled with ultraviolet and mass spectrometry (LC-UV-MS) and in total, 20 commercially-available aphrodisiac preparations were analyzed. The amount of yohimbine measured and expressed as the maximal dose per day suggested on product labels ranged from 1.32 to 23.16 mg. The second part of this work involved the phytochemical and pharmacological investigation of Erythroxylum vacciniifolium Mart. (Erythroxylaceae), a plant used in Brazilian traditional medicine as an aphrodisiac and tonic, and locally known as catuaba. With the aim of obtaining preliminary structure information on-line, the alkaloid extract was analyzed by high performance liquid chromatography (HPLC) coupled to diode array UV detection (LC-UVDAD), to mass spectrometry (LC-MS) and to nuclear magnetic resonance spectroscopy (LCNMR). Interpretation of on-line spectroscopic data led to structure elucidation and partial identification of 24 potentially original alkaloids bearing the same tropane skeleton. Seventeen new tropane alkaloids were then isolated from the alkaloid extract of the plant, including catuabines D to I, their derivatives and vaccinines A and B. All compounds were elucidated as tropane-diol or -triol alkaloids esterified by at least one 1-methyl-1H-pyrrole-2-carboxylic acid. One of the isolated compounds was identified as a tropane alkaloid N-oxide. Their structures were determined by high resolution mass spectrometry and multi-dimensional NMR spectroscopy. Among the numerous bioassays undertaken, only the cytotoxicity tests exhibited a weak positive activity of certain compounds.

The potential use of microcalorimetry in rapid differentiation between septic arthritis and other causes of arthritis.

Current diagnostic methods in differentiating septic from non-septic arthritis are time-consuming (culture) or have limited sensitivity (Gram stain). Microcalorimetry is a novel method that can rapidly detect microorganisms by their heat production. We investigated the accuracy and time to detection of septic arthritis by using microcalorimetry. Patients older than 18 years of age with acute arthritis of native joints were prospectively included. Synovial fluid was aspirated and investigated by Gram stain, culture and microcalorimetry. The diagnosis of septic arthritis and non-septic arthritis were made by experienced rheumatologists or orthopaedic surgeons. Septic arthritis was diagnosed by considering the finding of acute arthritis together with findings such as positive Gram stain or positive culture of synovial fluid or positive blood culture. The sensitivity and specificity for diagnosing septic arthritis and the time to positivity of microcalorimetry were determined. Of 90 patients (mean age 64 years), nine had septic arthritis, of whom four (44 %) had positive Gram stain, six (67 %) positive synovial fluid culture and four (44 %) had positive blood culture. The sensitivity of microcalorimetry was 89 %, the specificity was 99 % and the mean detection time was 5.0 h (range, 2.2-8.0 h). Microcalorimetry is an accurate and rapid method for the diagnosis of septic arthritis. It has potential to be used in clinical practice in diagnosing septic arthritis.

Single breath-hold 3D measurement of left atrial volume using compressed sensing cardiovascular magnetic resonance and a non-model-based reconstruction approach.

BACKGROUND: Left atrial (LA) dilatation is associated with a large variety of cardiac diseases. Current cardiovascular magnetic resonance (CMR) strategies to measure LA volumes are based on multi-breath-hold multi-slice acquisitions, which are time-consuming and susceptible to misregistration. AIM: To develop a time-efficient single breath-hold 3D CMR acquisition and reconstruction method to precisely measure LA volumes and function. METHODS: A highly accelerated compressed-sensing multi-slice cine sequence (CS-cineCMR) was combined with a non-model-based 3D reconstruction method to measure LA volumes with high temporal and spatial resolution during a single breath-hold. This approach was validated in LA phantoms of different shapes and applied in 3 patients. In addition, the influence of slice orientations on accuracy was evaluated in the LA phantoms for the new approach in comparison with a conventional model-based biplane area-length reconstruction. As a reference in patients, a self-navigated high-resolution whole-heart 3D dataset (3D-HR-CMR) was acquired during mid-diastole to yield accurate LA volumes. RESULTS: Phantom studies. LA volumes were accurately measured by CS-cineCMR with a mean difference of -4.73 ± 1.75 ml (-8.67 ± 3.54%, r2 = 0.94). For the new method the calculated volumes were not significantly different when different orientations of the CS-cineCMR slices were applied to cover the LA phantoms. Long-axis "aligned" vs "not aligned" with the phantom long-axis yielded similar differences vs the reference volume (-4.87 ± 1.73 ml vs. -4.45 ± 1.97 ml, p = 0.67) and short-axis "perpendicular" vs. "not-perpendicular" with the LA long-axis (-4.72 ± 1.66 ml vs. -4.75 ± 2.13 ml; p = 0.98). The conventional bi-plane area-length method was susceptible for slice orientations (p = 0.0085 for the interaction of "slice orientation" and "reconstruction technique", 2-way ANOVA for repeated measures). To use the 3D-HR-CMR as the reference for LA volumes in patients, it was validated in the LA phantoms (mean difference: -1.37 ± 1.35 ml, -2.38 ± 2.44%, r2 = 0.97). Patient study: The CS-cineCMR LA volumes of the mid-diastolic frame matched closely with the reference LA volume (measured by 3D-HR-CMR) with a difference of -2.66 ± 6.5 ml (3.0% underestimation; true LA volumes: 63 ml, 62 ml, and 395 ml). Finally, a high intra- and inter-observer agreement for maximal and minimal LA volume measurement is also shown. CONCLUSIONS: The proposed method combines a highly accelerated single-breathhold compressed-sensing multi-slice CMR technique with a non-model-based 3D reconstruction to accurately and reproducibly measure LA volumes and function.

Évaluation d'une structure gériatrique entre l'ambulatoire et l'hospitalier [Geriatric institutions, between ambulatory and hospital care: patients' description and performance assessment].

Introduction : Décrire les patients d'une structure gériatrique offrant des hospitalisations de courte durée, dans un contexte ambulatoire, pour des situations gériatriques courantes dans le canton de Genève (Suisse). Mesurer les performances de cette structure en termes de qualité des soins et de coûts. Méthodes : Des données relatives au profil des 100 premiers patients ont été collectées (huit mois), ainsi qu'aux prestations, aux ressources et aux effets (réadmissions, décès, satisfaction, complications) de manière à mesurer différents indicateurs de qualité et de coûts. Les valeurs observées ont été systématiquement comparées aux valeurs attendues, calculées à partir du profil des patients. Résultats : Des critères d'admission ont été fixés pour exclure les situations dans lesquelles d'autres structures offrent des soins mieux adaptés. La spécificité de cette structure intermédiaire a été d'assurer une continuité des soins et d'organiser d'emblée le retour à domicile par des prestations de liaison ambulatoire. La faible occurrence des réadmissions potentiellement évitables, une bonne satisfaction des patients, l'absence de décès prématurés et le faible nombre de complications suggèrent que les soins médicaux et infirmiers ont été délivrés avec une bonne qualité. Le coût s'est révélé nettement plus économique que des séjours hospitaliers après ajustement pour la lourdeur des cas. Conclusion : L'expérience-pilote a démontré la faisabilité et l'utilité d'une unité d'hébergement et d'hospitalisation de court séjour en toute sécurité. Le suivi du patient par le médecin traitant assure une continuité des soins et évite la perte d'information lors des transitions ainsi que les examens non pertinents. INTRODUCTION: To describe patients admitted to a geriatric institution, providing short-term hospitalizations in the context of ambulatory care in the canton of Geneva. To measure the performances of this structure in terms of quality ofcare and costs. METHOD: Data related to the clinical,functioning and participation profiles of the first 100 patients were collected. Data related to effects (readmission, deaths, satisfaction, complications), services and resources were also documented over an 8-month period to measure various quality and costindicators. Observed values were systematically compared to expected values, adjusted for case mix. RESULTS: Explicit criteria were proposed to focus on the suitable patients, excluding situations in which other structures were considered to be more appropriate. The specificity of this intermediate structure was to immediately organize, upon discharge, outpatient services at home. The low rate of potentially avoidable readmissions, the high patient satisfaction scores, the absence of premature death and the low number of iatrogenic complications suggest that medical and nursing care delivered reflect a good quality of services. The cost was significantly lower than expected, after adjusting for case mix. CONCLUSION: The pilot experience showed that a short-stay hospitalization unit was feasible with acceptable security conditions. The attending physician's knowledge of the patients allowed this system tofocus on essential issues without proposing inappropriate services.