[Relevance of fluoroquinolone use in Lorraine: results of the first survey]. / Revue de pertinence des fluoroquinolones en Lorraine: résultats de la première évaluation.

OBJECTIVES: The Antibiolor network assessed the good use of fluoroquinolones (FQ) in the French Lorraine region by a relevance review. METHODS: At the beginning of 2008, the experts in voluntary hospitals filled out a standard card mentioning the indication, FQ name, route, and duration according to prescriptions in the last 3 months. Two experts checked the relevance of prescriptions according to the local Antibioguide, and determined a score of therapeutic adequacy index for each card. Each establishment was given its results. Corrective measures were adopted at a meeting of the regional antibiotics commission in January 2009. RESULTS: One hundred and twenty-four units (61 medical, 33 surgical, 17 ICU, 2 ER, 11 long-stay hospital) in 28 hospitals filled 1538 cards. The most frequent indications were: pulmonary (632), urinary (445), digestive (130). The FQ indication was non-conform for 36% of the cards (n=554). When the FQ indication was justified (984 cards), the chosen molecule was non-conform in 222 cases (23%), dose in 115 cases (12%), duration in 250 cases (25%), and route of administration in 83 cases (8%). The prescriptions were entirely conform for 425 cards (28%). CONCLUSION: The Lorraine hospitals massively took part in this study. The second survey will use the same methodology. The objective will be to reduce the number of unjustified FQ prescriptions and to increase the number of conform cards.

Serum troponin Ic values in organ donors are related to donor myocardial dysfunction but not to graft dysfunction or rejection in the recipients.

BACKGROUND: Increased plasma cardiac troponin I (cTnI) values in heart donors are associated with donor myocardial dysfunction and increased risk of rejection in the recipients. We investigated the association between cTnI values and myocardial dysfunction in potential heart donors and the relationship between donors' cTnI values and recipients' early myocardial function and 1 year survival and risk of rejection. METHODS: cTnI was measured in 159 consecutive potential heart donors. Myocardial function was estimated by the left ventricular ejection fraction (LVEF) and segmental wall motion abnormalities (SWMA). Results are mean+/-SD (range) or median (interquartile range). RESULTS: cTnI values in potential donors were 2.1+/-5 ng/ml (0-40.4 ng/ml); cTnI values were significantly (P<0.001) higher: 4.2+/-5.9 ng/ml (0-30.6 ng/ml) for potential donors with LVEF <50% versus LVEF >50%: 1.7+/-4.7 ng/ml (0-40.4 ng/ml). cTnI values were significantly lower for donors without SWMA. cTnI values were significantly (P<0.001) lower for the 90 donors whose hearts were harvested: 1.1+/-2.3 ng/ml (0-15.6 ng/ml) versus the not harvested: 3.6+/-6.9 ng/ml (0-40.4 ng/ml). There were 87 recipients followed for 1 year. Donors' cTnI values were not associated with early alteration of LVEF, incidence of rejection or 1 year recipients' survival. CONCLUSION: Increased cTnI values in potential heart donors are statistically associated with myocardial dysfunction and could be helpful for organ selection. In contrast, cTnI values in heart donors were not associated with graft dysfunction or recipient survival after transplantation.

Air tube formation at the freezing transition in nematic liquid crystals.

A phenomenon is presented, which changes the shape of gas bubbles in liquid crystals and also creates long gas tubes. The system consists of air bubbles which are injected into a nematic liquid crystal host. The shape of these air bubbles changes from spherical to ellipsoidal by initiating freezing of the sample. Furthermore, long gas tubes are formed from the air which was formerly dissolved in the liquid crystal. The gas tubes are created by the progression of the crystalline-liquid interface. Their length can reach up to 40 times their diameter. The diameter of the tubes depends on the pressure applied to the system, as well as on the interface velocity.

Sequential measurements of troponin Ic values in brain-dead patients considered as potential heart donors.

It was suggested that a single value of normal or increased plasma cardiac troponin T or I (cTnT or cTnI) concentration could contribute to estimate donor myocardial damage and function in brain-dead patients. In patients with acute coronary syndromes, an initial normal value of troponin must be confirmed several hours later but no such recommendations exist for brain-dead patients. We investigated the relationship between two sequential (6 h interval) measurements of plasma cTnI concentrations in brain-dead patients considered as potential heart donors. The first and the second TnIc values were correlated with an adjusted r2 value of 0.92 (p<0.001). Our results suggest therefore that it is not necessary to repeat the measurements, when the value of plasma cTnI concentration is taken into consideration in the algorithm for cardiac harvesting.

Director-configurational transitions around microbubbles of hydrostatically regulated size in liquid crystals.

A high-pressure technique is introduced which allows a continuous variation of the inclusion size in liquid crystal colloids. We use a nematic liquid crystal host into which micrometer-sized gas bubbles are injected. By applying hydrostatic pressures, the diameter of these gas bubbles can be continuously decreased via compression and absorption of gas into the host liquid crystal, so that the director configurations around a single bubble can be investigated as a function of the bubble size. The theoretically predicted transition from a hyperbolic hedgehog to a Saturn-ring configuration, on reduction of the particle size below a certain threshold, is confirmed to occur at the radius of a few micrometers.

Buckling instability of droplet chains in freely suspended smectic films.

A buckling instability of chains of isotropic droplets in smectic films is investigated. The c -director field in a free-standing film is prepared as a target pattern with a continuous radial deformation. In such a pattern, isotropic liquid droplets are induced by light irradiation of the photochromic mesogenic material. The droplets align tangentially in regular chains in the regular structure of the c -director field. Incorporation of additional droplets lengthens the chains at a given ring diameter until they form complete rings. Further chain growth introduces a reversible buckling with a characteristic wave length. The phenomenon is similar in many respects to growth processes in biosystems or Euler buckling in polymer foils. A simple model of the wavelength selection mechanism is introduced.

Self-organization of isotropic droplets in smectic- C free-standing films.

Free standing smectic films have been investigated at the transition from the smectic- C phase to the isotropic phase. In the vicinity of the bulk transition temperatures, isotropic droplets of micrometer size appear in the film. Such systems represent convenient models for anisotropic, two-dimensional emulsions. A characteristic feature of the droplets is their mutual interaction by elastic distortions of the local orientation of the film, the c director, which are related to the anchoring conditions of the c director at the droplet border. We describe in detail the director deformations created by isotropic droplets of different sizes, and their role in the spontaneous organization of regular droplet patterns. Depending upon droplet size and anchoring strength, topological defects can be induced in the c -director field. Qualitative differences to literature data on cholesteric droplets in smectic- C* films are discussed.

[Analysis of the criteria that contribute to the decision to harvest the heart in brain-dead organ donors]. / Analyse des critères qui participent à la décision de prélèvement cardiaque chez les patients en état de mort encéphalique.

OBJECTIVES: The number of cardiac transplantation procedures does not increase because of the lack of donor hearts despite an increase in the number of brain-dead organ donors. The criteria used to select a donor heart are not formally standardized. The aim of the present study was to analyze the criteria that contribute to the selection of a donor heart. TYPE OF STUDY: Descriptive, retrospective study. PATIENTS AND METHOD: Clinical parameters, the initial causes that lead to brain death, maximum doses of catecholamines, several biochemical markers of myocardial ischaemia/necrosis as well as several echocardiography criteria were extracted from a prospectively collected database. Univariate and multivariate (logistic regression) analyses were performed with the "harvested heart" as dependent variable and the above-cited independent variables. RESULTS: One hundred and eighty consecutive brain-dead patients admitted from 1st October 1998 to 31st December 2000 out of which 112 gave at least one organ were analyzed. Among these 112 patients, 59 (39 males and 20 females) were pre-selected as potential heart donors. Only 44 hearts were harvested. Logistic regression analysis showed that harvesting of the heart was more probable if the donor were a male, had no left ventricle systolic wall motion abnormalities, had low doses of norepinephrine and low serum troponin Ic concentrations. CONCLUSION: After an initial phase of selection, the final decision to harvest a heart is based on several criteria. These results should be an incentive to conceive a score that could allow a more formal decision process for heart harvesting.

Granular dynamics of density profiles in a suspension interface.

The temporal evolution of the density profiles at the interface of a Rayleigh-Taylor instability in a sedimenting suspension is experimentally investigated. It is found that the sand-glycerin density gradients within the interface change with time, and that the evolution of the gradients differs significantly, depending on the location: The density profiles become steeper in the regions where the suspension flows downwards, whereas the profiles become flatter in the regions where the fluid flows upwards. This observation shows that there is a motion of the sand grains relative to the carrier fluid and hence reveals the prevailing granular dynamics in the suspension interface. It shows a behavior of the suspension which is different from the behavior of a homogeneous Newtonian one-component fluid whose density profiles do not change in time. Another interesting result is that the slopes of the profiles differ already at the very beginning (t=0) of the evolution of the instability, indicating that the suspension might have self-structured prior to instability onset.

SSR591813, a novel selective and partial alpha4beta2 nicotinic receptor agonist with potential as an aid to smoking cessation.

(5aS,8S,10aR)-5a,6,9,10-Tetrahydro,7H,11H-8,10a-methanopyrido[2',3':5,6]pyrano[2,3-d]azepine (SSR591813) is a novel compound that binds with high affinity to the rat and human alpha4beta2 nicotinic acetylcholine receptor (nAChR) subtypes (Ki = 107 and 36 nM, respectively) and displays selectivity for the alpha4beta2 nAChR (Ki, human alpha3beta4 > 1000, alpha3beta2 = 116; alpha1beta1deltagamma > 6000 nM and rat alpha7 > 6000 nM). Electrophysiological experiments indicate that SSR591813 is a partial agonist at the human alpha4beta2 nAChR subtype (EC50 = 1.3 micro M, IA =19% compared with the full agonist 1,1-dimethyl-4-phenyl-piperazinium). In vivo findings from microdialysis and drug discrimination studies confirm the partial intrinsic activity of SSR591813. The drug increases dopamine release in the nucleus accumbens shell (30 mg/kg i.p.) and generalizes to nicotine or amphetamine (10-20 mg/kg i.p.) in rats, with an efficacy approximately 2-fold lower than that of nicotine. Pretreatment with SSR591813 (10 mg/kg i.p.) reduces the dopamine-releasing and discriminative effects of nicotine. SSR591813 shows activity in animal models of nicotine dependence at doses devoid of unwanted side effects typically observed with nicotine (hypothermia and cardiovascular effects). The compound (10 mg/kg i.p.) also prevents withdrawal signs precipitated by mecamylamine in nicotine-dependent rats and partially blocks the discriminative cue of an acute precipitated withdrawal. SSR591813 (20 mg/kg i.p.) reduces i.v. nicotine self-administration and antagonizes nicotine-induced behavioral sensitization in rats. The present results confirm important role for alpha4beta2 nAChRs in mediating nicotine dependence and suggest that SSR591813, a partial agonist at this particular nAChR subtype, may have therapeutic potential in the clinical management of smoking cessation.

SR141716, a central cannabinoid (CB(1)) receptor antagonist, blocks the motivational and dopamine-releasing effects of nicotine in rats.

The central CB(1) cannabinoid receptor has recently been implicated in brain reward function. In the present study we evaluated first the effects of the selective CB(1) receptor antagonist, SR141716, on the motivational effects of nicotine in the rat. Administration of SR141716 (0.3 and 1 mg/kg) decreased nicotine self-administration (0.03 mg/kg/injection). SR141716 (0.3-3 mg/kg) neither substituted for nicotine nor antagonized the nicotine cue in a nicotine discrimination procedure, but dose-dependently (0.01-1 mg/kg) antagonized the substitution of nicotine for D-amphetamine, in rats trained to discriminate D-amphetamine. Secondly, using brain microdialysis, SR141716 (1-3 mg/kg) blocked nicotine-induced dopamine release in the shell of the nucleus accumbens (NAc) and the bed nucleus of the stria terminalis. To investigate whether SR141716 would block the dopamine-releasing effects of another drug of abuse, we extended the neurochemical study to the effect of ethanol, consumption of which in rodents is reduced by SR141716. Dopamine release induced by ethanol in the NAc was also reduced by SR141716 (3 mg/kg). These results suggest that activation of the endogenous cannabinoid system may participate in the motivational and dopamine-releasing effects of nicotine and ethanol. Thus, SR141716 may be effective in reduction of alcohol consumption, as previously suggested, and as an aid for smoking cessation.

Thixotropy in macroscopic suspensions of spheres.

An experimental study of the viscosity of a macroscopic suspension, i.e., a suspension for which Brownian motion can be neglected, under steady shear is presented. The suspension is prepared with a high packing fraction and is density matched in a Newtonian carrier fluid. The viscosity of the suspension depends on the shear rate and the time of shearing. It is shown that a macroscopic suspension shows thixotropic viscosity, i.e., shear thinning with a long relaxation time as a unique function of shear. The relaxation times show a systematic decrease with increasing shear rate. These relaxation times are larger when decreasing the shear rates, compared to those observed after increasing the shear. The time scales involved are about 10 000 times larger than the viscous time scale tau(visc)=a2/nu and about 1000 times smaller than the thermodynamic time scale tau(therm)=Pe/gamma. (a is the gap width of the viscometer, nu is the kinematic viscosity, Pe=6pi(eta)gamma;tau)3/(k(B)T) is the Péclet number and gamma; is the shear rate.) The structure of the suspension at the outer cylinder of a viscometer is monitored with a camera, showing the formation of a hexagonal structure. The temporal decrease of the viscosity under shear coincides with the formation of this hexagonal pattern.

Rayleigh-Taylor instability in a sedimenting suspension.

The temporal evolution of an interface between glycerin and a glycerin-sand suspension of small packing fraction (obtained using the hindered settling phenomenon) driven by gravity is experimentally investigated. The growth rates for the different wave numbers characterizing the developing front are determined by means of a Fourier analysis. To model the observed behavior, we apply the idea of the Rayleigh-Taylor instability for a homogeneous fluid with vertically varying density and viscosity (one-fluid model). A good agreement between the experimental and theoretical results is obtained.

Evaluation of donor cardiac function for heart transplantation: experience of a French academic hospital.

OBJECTIVES: The diagnostic and therapeutic approaches for evaluation and management of cardiac function in brain-dead patients vary from country to country. The aim of the present study was to describe the results of the evaluation of brain-dead patients as potential cardiac donors in a French teaching hospital that manages the largest number of brain-dead patients in France. METHODS: Demographic parameters, the causes of brain death, clinical evolution, hemodynamic parameters, doses of inotropic and/or vasopressive drugs, the results of echocardiographic examination, and several biochemical markers of myocardial cell injury were retrospectively collected. RESULTS: Seventy-one consecutive brain-dead patients admitted to the intensive care unit of the Academic Hospital of Nancy from October 1st, 1998 to September 30, 1999 were analyzed. Twenty-nine patients were considered as potential heart donors: 22 males and 7 females aged 33 +/- 3 years (Mean + SEM). The cause of brain death was head trauma in 17 cases (59%), cerebrovascular disease in 10 cases (34%), and cerebral anoxia related to cardiac arrest in 2 cases (7%). Eighteen hearts (18/29 or 66%) were harvested and transplanted with a favorable outcome at one month in 17 cases. In 11 cases, the heart was not harvested, nine (9/29 or 31%) because of myocardial dysfunction upon subsequent echocardiographic examination and 2 because of the lack of matched recipients. CONCLUSION: Comparison of these results with those of other groups suggests that hormonal substitution with insulin and triiodothyronine in the presence of myocardial dysfunction could be of potential interest to correct myocardial dysfunction and increase the number of donor hearts.

Variations in plasma sodium concentration in post-operative patients depend on an electrolyte-free water balance, part of a tonicity balance.

BACKGROUND: There is an inverse relationship between changes in the concentration of sodium in plasma (PNa) and intracellular fluid (ICF) volume. Intakes and losses of sodium (Na), potassium (K) and water can be divided into two volumes: isotonic and electrolyte-free water (EFW). Calculations of these volumes assess a tonicity balance, a tonicity imbalance results in a change of PNa: when EFW is added to body fluids, PNa decreases. Moreover, the concept of EFW permits a good understanding of the renal contribution to the defence of body tonicity. PURPOSE: To illustrate that the measurement of a tonicity balance provides the best estimate of changes in PNa in an ICU setting. METHODS: Twenty-two patients were admitted to the Post-Operative Intensive Care Unit. We investigated how well changes in EFW balance correlated with PNa variations and what is the best formula to calculate EFW in this setting. RESULTS: PNa changes depend on EFW balance; there is no significant relationship with other classical factors such as urinary osmolality or Na-free water. CONCLUSION: The utility of a tonicity balance is demonstrated. A formula is derived facilitating at the bedside the prediction of changes in PNa following fluid therapy: PNa2 = [(PNa1.TBW) + balance (Na + K)]/[TBW + balance H2O]. PNa changes can be understood and/or modified exclusively by a careful measurement of intakes and losses of Na, K and water.

[Complications of vascular surgery]. / Complications de la chirurgie vasculaire.

Vascular surgery, which in certain life-threatening situations is the only possible therapeutic option, has progressed considerably since its beginning in the 1950s. Because of the constant progression of vascular diseases, this surgery will present, in the forthcoming years, a major public health problem. Because of advances in medico-surgical management, evermore elderly and frail patients can be treated. Perioperative mortality is constantly decreasing, but much progress remains to be accomplished to prevent, avoid or treat, postoperative complications. They are common and serious in these typical patients with cardiovascular diseases (men over 50 years of age, heavy smokers, atheromatous ...). The AA divide these complications into 3 main groups depending on the surgical procedure: abdominal aortic surgery, carotid surgery and arterial and venous surgery of the lower limbs. There is much data on abdominal aortic surgery because these long and complex procedures produce repercussions often involving many systems. The postoperative complications are treated according to the system they involve: cardiovascular, the most serious, respiratory, the commonest, alimentary, neurological, renal, others, as well as combined systems. The AA do not deal with the specific problems associated with cardiac and cardio-thoracic surgery. The AA discuss the different epidemiological findings of the large surgical series published in the 1970s and 1980s. The more recent literature analyses the relationship between preoperative risk factors (atheroma, COAD, hypertension ...), peroperative problems (surgical difficulties, emergencies, massive transfusions, others) and the corresponding postoperative morbidity. Thus a few general outlines of the physiopathology of these different complications emerge. In the light of these notions the few proposed methods will be evaluated in order to improve the preoperative condition of the vascular patient. The AA also review the relevance of the preoperative investigation in patients for vascular surgery. All these measures aim at reducing the incidence and severity of perioperative morbidity.

Assessment of deep vein thrombosis prophylaxis in surgical patients: a study conducted at Nancy University Hospital, France.

OBJECTIVE: This retrospective evaluation aimed to assess the adequacy of prophylaxis against thromboembolism prescribed to surgical patients at the authors' institution, and to compare it with generally accepted published guidelines. Aspects considered were indications for prophylaxis, regimens used and monitoring. METHODS: Eleven units (nine surgical and two surgical intensive care) took part in the survey on a voluntary basis. The clinical audit system used involved developing a set of criteria based on existing guidelines, comparing observed practice with those recommendations, analysing the factors underlying any deviation and developing corrective measures. RESULTS: When the medical records of 117 patients hospitalized in October 1995 were examined, prophylaxis against deep vein thrombosis was documented in 86 (low molecular weight heparin in 85, dextran in one). No associated physical preventative measures were recorded. Indications and dosage were appropriately handled in 90.7% and 75.2% of patients, respectively. Ninety-five cases were outside the reference criteria: 74 for excluded surgical indications, 13 which involved laparoscopy, and eight in which spinal or epidural anaesthesia was administered. Platelet count was performed in 73.8% of cases before prophylactic treatment, and in 23.10% during its course. Anti-Xa activity was measured in 0.4% of cases. Analysis of causes showed that guidelines were not complied with either because of lack of organization, or because of disagreement with them. DISCUSSION: In this study, indications for prophylaxis were well established and heparin dosages used were not fundamentally flawed. The weak point in practice was a failure to carry out platelet counts, particularly during the course of treatment. Appropriate corrective action consists of disseminating guidelines and relevant information, and using a preoperative checklist to assess thromboembolic risk. CONCLUSION: Physicians agree that opportunities to improve preventative practices exist, and that the quality improvement programme should be pursued.