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Biomedical subjects

A Maître

Publications and source records attributed to A Maître.

18 recordsLinked to original sources
PubMed2003

Conditional preparation of a quantum state in the continuous variable regime: generation of a sub-Poissonian state from twin beams.

We report the first experimental demonstration of conditional preparation of a nonclassical state of light in the continuous variable regime. Starting from a nondegenerate optical parametric oscillator which generates above threshold quantum intensity correlated signal and idler "twin beams," we keep the recorded values of the signal intensity only when the idler intensity falls inside a band narrower than its standard deviation. By this very simple technique, we generate a sub-Poissonian state 4.4 dB (64%) below shot noise from twin beams exhibiting 7.5 dB (82%) of noise reduction in the intensity difference.

Journal Article↗
PubMed2003

Municipal waste incinerators: air and biological monitoring of workers for exposure to particles, metals, and organic compounds.

AIMS: To evaluate occupational exposure to toxic pollutants at municipal waste incinerators (MWIs). METHODS: Twenty nine male subjects working near the furnaces in two MWIs, and 17 subjects not occupationally exposed to combustion generated pollutants were studied. Individual air samples were taken throughout the shift; urine samples were collected before and after. Stationary air samples were taken near potential sources of emission. RESULTS: Occupational exposure did not result in the infringement of any occupational threshold limit value. Atmospheric exposure levels to particles and metals were 10-100 times higher in MWIs than at the control site. The main sources were cleaning operations for particles, and residue transfer and disposal operations for metals. MWI workers were not exposed to higher levels of polycyclic aromatic hydrocarbons than workers who are routinely in contact with vehicle exhaust. The air concentrations of volatile organic compounds and aldehydes were low and did not appear to pose any significant threat to human health. Only the measurement of chlorinated hydrocarbon levels would seem to be a reliable marker for the combustion of plastics. Urine metal levels were significantly higher at plant 1 than at plant 2 because of high levels of pollutants emanating from one old furnace. CONCLUSION: While biological monitoring is an easy way of acquiring data on long term personal exposure, air monitoring remains the only method that makes it possible to identify the primary sources of pollutant emission which need to be controlled if occupational exposure and environmental pollution are to be reduced.

Air Pollutants, Occupational↗
PubMed2002

Surpassing the standard quantum limit for optical imaging using nonclassical multimode light.

Using continuous wave superposition of spatial modes, we demonstrate experimentally displacement measurement of a light beam below the standard quantum limit. Multimode squeezed light is obtained by mixing a vacuum squeezed beam and a coherent beam that are spatially orthogonal. Although the resultant beam is not squeezed, it is shown to have strong internal spatial correlations. We show that the position of such a light beam can be measured using a split detector with an increased precision compared to a classical beam. This method can be used to improve the sensitivity of small displacement measurements.

Journal Article↗
PubMed2002

[How do we reduce the under-reporting of occupational primary lung cancer].

UNLABELLED: The under-reporting of occupational lung cancer is due to insufficient recognition of occupational exposure and inadequate medico-legal action. MATERIALS AND METHODS: All cases of primary bronchial carcinoma seen at the University Hospital of Grenoble between October 1996 and December 1998 completed a standardised questionnaire set by a physician in occupational medicine. When evidence of exposure to occupational carcinogens was established a claim for occupational disease was made and the outcomes of these claims were obtained from the Department of Social Security at the end of 2000. RESULTS: Asbestos was the most common carcinogenic agent found, followed by crystalline silica, diesel fumes, metals, paints and ionising radiation. Among the 305 patients in the study with primary bronchial carcinoma 20% were able to make a claim for occupational disease whereas only 2% would have claimed otherwise. The Department of Social Security accepted 77% of the 39 claims for occupational disease submitted, thus giving a 12% incidence of occupational bronchial carcinoma in this group. CONCLUSION: It is important to inform and instruct doctors of the environmental risks that are additional to those of tobacco smoking and of the need of inquire into any exposure to carcinogenic agents in order to ensure that the victims receive the appropriate medico-legal benefits. Improved primary prevention alone might eventually avoid the development of up to 3 500 cases of occupation bronchial carcinoma per year in France.

Disease Notification↗
PubMed2001

Method for confirmation of synthetic corticosteroids in doping urine samples by liquid chromatography-electrospray ionisation mass spectrometry.

In this study, we report on the development of a method to confirm simultaneously nine of the most commonly abused synthetic corticosteroids in urine based on liquid chromatography-electrospray ionisation mass spectrometry. A considerable simplified sample preparation procedure, including liquid-liquid phase extraction with Extrelut-NT3 columns, provided both excellent sample purification and high overall recoveries. Complete HPLC separations were obtained on a reversed-phase column with 1 mM ammonium acetate-acetonitrile (60:40, v/v) as mobile phase. Mass spectral acquisition was done in the negative ion, and selected ion monitoring modes to identify the drugs with at least three characteristic ions. Detection limits were determined at < or =1 ng/ml and the confirmation limits at 1 to 5 ng/ml.

Adrenal Cortex Hormones↗
PubMed2000

Ambulatory blood pressure variation in normotensive subjects in relation to the sitting or standing position.

OBJECTIVE: To evaluate the physiological variations in arterial blood pressure in normotensive subjects during activity and in relation to the sitting or lying position. METHODS: The subjects were 30 healthy volunteers who were normotensive and receiving no treatment. Blood pressure was measured using the validated monitor Diasys Integra (NOVACOR SA, Rueil-Malmaison, France) with an integral position sensor. Blood pressure was recorded every 15min over a 24h period, additional measurements being made in the first, third and sixth minutes after standing up. RESULTS: During the active period (1000-2000h), 53% of the measures were made in the standing position. Over this period, the values of systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate were significantly elevated in the standing position in comparison to the sitting position. The difference was of the order of 5mmHg for the SBP, 3.5mmHg for the DBP and 9beats/min for the heart rate. The SBP, DBP and heart rate measured in the first, third and sixth minutes after standing up were not significantly different. CONCLUSION: When measuring the blood pressure and heart rate in ambulatory patients, it seems justified to evaluate the patient's position during monitoring in order to achieve a better reproducibility and also to uncover any problems of blood pressure control with positional change, as could exist in patients with autonomic dysfunction. This might also aid in evaluating antihypertensive treatment and also any deleterious hypotensive effects.

Adult↗
PubMed1996

Urinary hexane diamine as an indicator of occupational exposure to hexamethylene diisocyanate.

The occupational exposure of 19 men to hexamethylene diisocyanate (HDI) vapour was monitored during one 8-h shift. It ranged from 0.30 to 97.7 micrograms/m3. This was compared with the urinary output of hexane diamine (HDA) liberated by acid hydrolysis from its conjugates in post-shift samples. The excretion varied from 1.36 to 27.7 micrograms g creatinine, and there was a linear association of HDI air concentration with urinary HDA excretion. The validity of the urinary analysis was confirmed by simultaneous blind analysis in another laboratory. The results had an excellent linear concordance. Thus, it seems that while the gas chromatographic-mass spectrometric detection method requires sophisticated apparatus, the results are very useful to occupational health practices. A biological exposure index limit of 19 micrograms HDA/g creatinine in a post-shift urine specimen is proposed as an occupational limit level of HDI monomer (time-weighted average = 75 micrograms/m3). Most importantly, biological monitoring of HDA is sensitive enough to be used at and below the current allowable exposure limit levels.

Aerosols↗
PubMed1993

Biological monitoring of occupational exposure to toluene diisocyanate.

The study validated the use of urinary toluene diamine (TDA) in postshift samples as an indicator of preceding 8-h exposure to toluene diisocyanate (TDI). Nine workers exposed in TDI-based polyurethane foam production were studied. Their exposure levels varied in 8-h time-averaged samples from 9.5 to 94 micrograms/m3. The urinary TDA concentrations varied from 6.5 to 31.7 micrograms/g creatinine and they were linearly related to the atmospheric TDI levels. Approximately 20% of TDI is metabolized to diamines but their specificity is remarkable to the extent that by analysis for the 2,4- and 2,6-diamino isomers an idea of the percutaneous absorption may be had.

Air Pollutants, Occupational↗
PubMed1991

[Study of the 24 hour blood pressure profile in normotensive type I diabetic patients].

A number of studies have shown changes and even an inversion of the diurnal cycle in certain affections: Cushing's syndrome, pheochromocytoma, severe renal failure, autonomous nervous system disorders, pre eclampsia etc.... The authors studied diurnal and nocturnal variations of blood pressure in type I diabetics. Twenty-nine normotensive (WHO criteria) type I diabetics (NTD) average age 34.9 +/- 11 years, with diabetes of 13.6 +/- 8 years standing, and 118 normotensive non-diabetics (NT) aged 20 to 60 years (distributed by decennies according to age and sex) were studied. The systolic (SBP) and diastolic blood pressures (DBP) were recorded at rest in the decubitus position by the phase V indirect auscultatory method and during ambulatory monitoring (automatic Spacelabs no. degrees 90207 device) every 15 minutes during the daytime and 20 minutes during the night. The mean values were studied; the values of the heart rates were identical in the NTD and NT populations. Significant difference in SBP between the Nt and NTD were recorded: during daytime there was no difference either in SBP or DPB; during the night, there was a significant difference in SBP. A study of the day-night differences both in absolute and in relative values (day-night difference with respect to daytime values as a percentage) did not show any statistically significant differences between the two populations. Abnormalities of the 24 hour profile, defined as absence of a 5 mmHg fall in nocturnal BP values, were looked for but there were no differences between the NT and NTD subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Role of ambulatory blood pressure measurement in the evaluation of the cardiovascular load in high altitude workers].

UNLABELLED: This study evaluates ambulatory blood pressure ABP measurement as a technique for measuring the cardiovascular load in maintenance mechanics working on mechanical lifts at altitudes of over 2,500 meters (stress due to altitude and intensive static and dynamic work). METHOD: 25 normotensive workers were studied during real working conditions. Each subject underwent a maximal stress test, and echocardiography. An ABP recording (Spacelab 90207) with BP measurement every 15 minutes and continuous heart rate (HR) monitoring (Essilor IFC85), during 24 hours were performed on the same day. ANALYSIS: study of BP levels and their factors of variation, comparison of this data with continuous HR measurements, and with results of the stress test and echocardiography. RESULTS: even in difficult conditions (while balancing on cables and cable towers), ABP measurements is possible (less than 10% missing values). Systolic (SBP) and diastolic (DBP) blood pressure and HR values adjusted for age are significantly higher during work activity (9:00-12:00, 14:00-15:00) in these subjects than in reference normotensive subjects. ABP did not differ significantly between different types of work while the equivalent mechanical load (work load that gives a stress test HR equal to the mean HR during work) reveals a different between work activities. At night SBP remains higher and HR values lower than in control subjects. In comparison with reference criteria, 3 subjects were considered as having an abnormally high ABP during the daytime. ABP results were not linked with number of years in the profession nor with the altitude at which the subject worked or lived. Although 40% of subjects have a left ventricular mass index greater than 135 g:m2, there is no link between ultrasound and ABP parameters. CONCLUSION: while ABP measurement seems possible in this type of professional activity, BP values do not appear to be correlated to work level measured. The absence of correlation with left ventricular mass, suggests that the process of cardiovascular adaptation is different from that in even moderately hypertensive subjects.

Adaptation, Physiological↗
PubMed1991

[Nyctohemeral changes of blood pressure. Diagnostic and prognostic value].

The blood pressure shows circadian variation in normal subjects with higher diurnal than nocturnal values: the difference between day and night time blood pressure is about 10-20 mmHg for systolic and for diastolic blood pressure. These variations are mainly related to physical and/or psychosensorial stress: the physician is himself a cause of increased blood pressure (the "white coat" effect). The degree of the nocturnal decrease in blood pressure which is maximal 2 and 3 o'clock is related to the quality and depth of sleep. The nocturnal decrease is followed by an increase in blood pressure when the person wakes up (early morning peak). Diagnostic signs: a physiological inversion of the circadian rhythm may be observed in people who sleep during the daytime and work at night. There would seem to be less of a nocturnal fall in black persons in the United States. Some pathological conditions can inverse or at least disturb the ciacadian variation: apart from hypertension, this has been reported in autonomic nervous system disease, in diabetics with autonomic neuropathy in some elderly patients, in Cushing's syndrome, after cardiac transplantation, etc... In hypertensives, the lack of nocturnal decrease of the blood pressure or an inversion in circadian rhythm should be looked for in severe and secondary hypertension such as associated with pheochromocytoma, or in renal dialysis patients. In toxaemia of pregnancy, this abnormality may herald an eclamptic crisis. Prognostic signs: in normotensives (especially in black persons) and hypertensives, inversion of the circadian rhythm is associated with more severe left ventricular hypertrophy and a higher morbidity.

Adult↗