[Cost/effectiveness comparison of the vaccine campaign and reduction of sick leave, after vaccination against influenza among the Clermont-Ferrand University Hospital staff]. / Comparaison coût/bénéfice de la campagne vaccinale et de la réduction de l'absentéisme, après vaccination contre la grippe du personnel du CHU de Clermont-Ferrand.

OBJECTIVE: The aim of this study was to compare the cost of vaccination for the Clermont-Ferrand University hospital (CHU) personnel and the cost of sick leave among vaccinated and non-vaccinated employees in 2003, 2004, and 2005. DESIGN: The study included 7256 CHU staff (medical and non-medical personnel). The cost of sick leave was calculated on the basis of short-term disease (four to nine days) over the three months of the epidemic season in 2004, 2005, and 2006. RESULTS: In 2005, the overall cost of vaccination was 4.02 euros per vaccinated employee. Over the three years, the total sick leave reached 804 days for employees vaccinated against 5670 for non-vaccinated employees. In 2003, 2004, and 2005, the vaccinal coverage was 13, 20.5, and 30.1%, the mean duration of sick leave was 0.16, 0.17, and 0.18 day among vaccinated staff, and 0.26, 0.39, and 0.34 day among non-vaccinated staff corresponding to a benefit per vaccinated employee of 5, 26, and 20 euros, respectively for each year. The total benefit for the institution was 86,458 euros (4630+38,168+43,660). If the vaccinated rate of 75% recommended by the Haute Autorité de santé (HAS) had been reached, the additional benefit would have been 250,193 euros (33,157+152,256+65,180). CONCLUSIONS: The number of sick leave days and the related cost were approximately twice less important for vaccinated employees, economically justifying this vaccination including a period of weak epidemic, as checked over three consecutive years.

[Analysis of motivations for antiflu vaccination of the Clermont-Ferrand University Hospital staff]. / Analyse des motivations à la vaccination antigrippale du personnel du CHU de Clermont-Ferrand.

OBJECTIVE: The vaccination of hospital staff decreases patient mortality and disorganization of services due to sick leave. The main aim of our study was to determine the Clermont-Ferrand University hospital (CHU) personnel's motivations for or against antiflu vaccination to increase the effectiveness of prevention campaigns. DESIGN: An autoquestionnaire with multiple choices was given to the 7601 CHU staff in May 2005. It documented socioprofessional characteristics, vaccinal status, and reasons for vaccination, nonvaccination, or stopping antiflu vaccination. RESULTS: The answer rate was 26.5% (2011 autoquestionnaires returned) and representative of the CHU staff. The rate of vaccination in 2004 was 36.35% with a strong correlation between vaccination and former influenza infection (p<0.001). Five of the six principal reasons for vaccination were altruistic including the first two: avoiding transmission to patients (61.8%) and his family (59.8%). The main reason for stopping was the lack of time. The reasons for nonvaccination were linked to a feeling of invulnerability: conviction of not being at risk, of being too young, or in good health. CONCLUSIONS: The Haute Autorité de santé's objective of vaccinal coverage against influenza for 75% of the health professionals requires their active compliance. The effectiveness of future campaigns could aim at improving knowledge by insisting particularly on the young age of the risk populations. The lack of time can be compensated by offering on-site vaccination, including at night and by proposing larger schedules for vaccination.

Median maximal heart rate for heart rate calibration in different conditions: laboratory, field and competition.

The objective of this study was to evaluate the variability of maximal heart rate in three different conditions: laboratory tests, field tests, and competitions. Sixteen male endurance volunteers were tested in five exhaustive tests for each condition. All exhaustive events were heart rate monitored (Accurex plus, Polar Electro, Finland) and true maximal heart rates were assessed and compared with each other and with predicted maximal heart rates. Results show that under the three conditions HR(peaks) were not statistically different (p = 0.62, NS, Friedman test). Mean HR(peaks) (SD) were: laboratory = 194.3 (7.8), field = 193.8 (11.8), competition = 192.3 (10.1) beats x min(-1). Conditions for reaching individual heart rate peak were in the laboratory (treadmill VO(2)max protocol) for 5 subjects, in field tests for 7 subjects and in competitions for 6 subjects (two circumstances for two subjects). A large intra-individual variation existed in the three circumstances (+/- 6 beats x min(-1)). Absolute median maximal heart rate was 190.0 bpm (9.32) i.e 7.6 bpm lower than heart rate peak. Both were highly related (rho = 0.89, z = 3.449, p = 0.0006, Spearman test). Median maximal heart rates inter-condition relationship were higher. Median maximal heart rate was more stable and took more information into account than an isolated peak. It gives a central value that minimizes the potential risk of under or over estimation when calibrating exercise intensities with HR.

Ability of new heart rate monitors to measure normal and abnormal heart rate.

BACKGROUND: The extended use of heart rate monitors to non sportive people, and older ones increases the risk to be facing heart rate troubles. Questions exist upon the ability of this devices to detect such abnormalities. The purpose of the investigation was to evaluate the accuracy of two third generation heart rate monitors, Accurex Plus and Vantage NV and to compared these data with those of an older one, PE 4000. Then we investigate responses of this monitors to abnormal heart rate. EXPERIMENTAL DESIGN: The three heart rate monitors were tested in the laboratory, wired in parallel to an ECG simulator under two modes: a normal heart rate program (7 stable heart rate stages with two marked transitions) and an automatic arrhythmia one. MEASURES: 1st program: Values generated by the ECG simulator were compared to the values produced by the three devices. Particular attention was paid to the transition phases (heart rate drop and heart rate fall). Results of heart rate monitors accuracy were expressed at the exact value (devices value=simulator value) and at approximated value of +/-3 beats x min(-1) (devices value=simulator value +/-3 beats x min(-1)); 2nd program: Abnormal rhythms were analysed using an ambulatory ECG recorder (Synésis) as control data, and compared to the data from the three devices. STATISTICS: Correlation between simulator generated true values and HRMs read values were calculated. RESULTS: In the 1st normal heart rate program, with an accuracy of exact value, Accurex Plus and Vantage NV, were more accurate than the PE 4000 (94% and 89% of values respectively versus 33% for the PE4000). At +/-3 beats x min(-1), the three devices gave good results: over 98% of total values. In transition phases: the three devices showed a smoothing effect, which was stronger in decelerating heart rate than in accelerating heart rate. In the 2nd program: isolated heart rhythm troubles (missing beat, pause <4 sec, supra-ventricular ectopic activity, and ventricular ectopic activity) were either not detected or were rejected. Signal changes such as changes in QRS (ventricular bigeminy) may cause detection losses, and so modify calculated heart rate. The HR signal rising/dropping slopes caused by sudden heart rhythm disorders, were notably attenuated, with a consequent loss of HR accuracy. CONCLUSIONS: In laboratory stable heart rate conditions, third generation HRMs are more accurate than earlier ones. Heart rate monitors are less accurate in transient phases and have not been improved in that domain. The three HRMs ignore isolated heart rate troubles. As expected, the usefulness of HRMs in detecting HR disorders is limited. Nevertheless, these devices have some value with serious troubles, like pause, bradycardia or tachycardia, lasting longer than 4 sec, and especially if they coincide with functional symptoms. The use of such even more accurate devices may consequently be recommended to healthy public for which they were built.

Heart rate monitors and abnormal heart rhythm detection.

We test the accuracy of two third generation heart rate monitors (HRM), Accurex Plus and Vantage NV and compare these data with those of an older monitor, PE 4000. Then we investigate responses of the HRM's to abnormal heart rhythms (HR). Accurex Plus and Vantage NV, and PE 4000 were tested in the laboratory under both stable and transient conditions. The Phantom 320 HR simulator gave 7 stable heart rates, each lasting 3 min. The responses of the HRM's to abnormal heart rhythms were tested with an automatic arrhythmia program lasting 17 min. The new HRM's, Accurex Plus and Vantage NV, were more accurate (89 to 94% and over 98% at +/-3 beats per min) in the stable state than the PE 4000. They all showed a smoothing effect in transient measurements, which was stronger in decelerating HR (1st case) than in accelerating HR (2nd case). - 1st case: Accurex Plus =Vantage NV >PE 4000 -2nd case: PE 4000 >Accurex =Vantage. Most isolated heart rhythm disorders (missing beat, pause < 4 s, SVEA, and SVT) were either not detected or rejected. Signal changes such as changes in QRS (ventricular bigeminy) may cause detection losses, and so modify calculated heart rate. HR signal rising/dropping slopes caused by sudden heart rhythm disorders, was notably attenuated, with a consequent loss of HR accuracy. Although the usefulness of HRM's in detecting HR disorders is limited, they have some value with serious disorders, like pause >4 s, important bradycardia or tachycardia.

Inter-relationships between pituitary-adrenal hormones and catecholamines during a 6-day Nordic ski race.

The aim of the study was to investigate the inter-relationships between pituitary-adrenal hormones and catecholamines during a prolonged competition over 6 days. Plasma adrenocorticotropic hormone (ACTH), cortisol (C), beta-endorphin (beta EP), free and sulphated adrenaline (A) and noradrenaline (NA) were measured in 11 volunteer male subjects during a national Nordic-ski race (323 km). Blood samples were obtained before the competition in the evening as control (D0), and before and after each day's racing (D1-D6). The mean daily heart rate (fc) was calculated from fc values recorded every minute during the race. The results showed the following: changes in mean fc [from 147 (SEM 3) to 156 (SEM 3) beats.min-1 according to the day] were not significant during the race. Diurnal variations in ACTH, beta EP and C were no longer apparent after the race: evening levels were higher than their respective D0 values during the race, except on D3 when there was a lack of response to exercise in the three hormones. Unlike ACTH and beta EP, pre- and postexercise C values on D1 and D2 were higher than those on the subsequent days (P less than 0.001). In contrast, there was a progressive accumulation of A and NA in pre- and postrace concentrations which reached a plateau in about 4 days. Positive correlations between exercise responses in ACTH, C and beta EP were found especially on D3 and D6 (P less than 0.001) but there were no significant correlations between catecholamines and the other three hormones. Thus, prolonged competition over 6 days evoked different control mechanisms for hormones of the pituitary-adrenal axis and catecholamines.(ABSTRACT TRUNCATED AT 250 WORDS)

Change in the physical state of platelet plasma membranes upon ionophore A23187 activation. A fluorescence polarization study.

Human platelets were isolated and fluorescence-labelled by 1,6-diphenylhexatriene. Diphenylhexatriene was essentially localized in the plasma membrane, as indicated by trinitrobenzenesulfonate-quenching experiments. A decrease of the fluorescence polarization of diphenylhexatriene was observed upon ionophore A23187 addition in the absence of aggregation. 0.3 microM ionophore allowed to reach the maximum rate of the decrease of fluorescence polarization; it also maximally stimulated the light transmission change, the serotonin release and the thromboxane B2 synthesis. The amplitude of the fluorescence polarization decrease was maximum at platelet concentrations between 4 X 10(7) and 7 X 10(7)/ml. The presence of Ca2+ in the medium increased the rate constant of the polarization change. Chlorpromazine (60 microM) completely inhibited this transition, but at 30 microM its inhibitory effect was reversed by Ca2+. The membrane events implied in platelet activation very likely lead to fluidization of the plasma membrane, perhaps by its fusion with the membranes of internal granules which are relatively depleted of cholesterol. Ca2+ plays a central role in the triggering of the observed effects at the membrane level.

Excitation energy transfer from tryptophan residues of peptides and intrinsic proteins to diphenylhexatriene in phospholipid vesicles and biological membranes.

An efficient excitation energy transfer from tryptophan residues of intrinsic membrane proteins to an extrinsic fluorescent probe (diphenylhexatriene) has been demonstrated in rat erythrocyte ghosts. To correlate this transfer with the localization of the probe, a model system has been investigated. It consists of peptides containing lysine and tryptophan residues bound to negatively charged phosphatidylserine vesicles. Absorption and fluorescence spectroscopies were used to follow peptide binding and diphenylhexatriene incorporation. Peptide binding is accompanied by a blue shift of the tryptophan fluorescence together with an increase of the quantum yield and of the fluorescence decay time. An experimental Föster critical distance value of 4.0 nm was found for energy transfer from tryptophan residues of peptides to diphenylhexatriene which approaches the range of calculated values (3.1-3.7 nm) using a two-dimensional model. These results demonstrate that efficient energy transfer can occur from tryptophan residues of intrinsic proteins to diphenylhexatriene without any interaction between diphenylhexatriene and proteins in biological membranes.

Interaction between phospholipid bilayer membranes and the polyene antibiotic amphotericin B: lipid state and cholesterol content dependence.

The interaction between amphotericin B and egg yolk phosphatidylcholine, dimyristoyl (DMPC) and dipalmitoyl phosphatidylcholine (DPPC) phospholipid bilayer vesicles has been monitored by the circular dichroism (CD) spectra of amphotericin B at a 1 . 10(-5) M concentration. This method has revealed that amphotericin B may be present in a number of different forms depending on the time elapsed after the mixing, the cholesterol content of the vesicles and the vesicles' physical state. Some striking features of these CD detected species are the following: with egg yolk phosphatidylcholine and a molar cholesterol percentage lower than 25, at 25 degrees C several forms are coexistent, their amount is time-dependent; with dipalmitoyl or dimyristoyl phosphatidylcholines without cholesterol or with a cholesterol molar percentage lower than 25, in the gel state, a form different from the former appears very rapidly; with egg yolk phosphatidylcholine, DMPC and DPPC at a molar cholesterol percentage between 25 and 50 a new form is monitored, identical in the three cases and observed in the liquid crystalline state as well as in the gel state. In the case of the three phospholipids without cholesterol a definite interaction with the antibiotic is observed but with different characteristics according to the nature of lipid. With amphotericin B 'Fungizone' the same species are monitored but their appearance is much slower. Two explanations are proposed for the origin of the discrepancies between CD and electronic absorption.