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Biomedical subjects

J M Mallion

Publications and source records attributed to J M Mallion.

At least 91 records · Page 5Linked to original sources
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↗
PubMed1996

Benefits of electronic pillboxes in evaluating treatment compliance of patients with mild to moderate hypertension.

OBJECTIVE: This study was designed to assess the compliance of hypertensive patients with a once-daily regimen of the angiotensin converting enzyme (ACE) inhibitor trandolapril and to evaluate the antihypertensive efficacy of the drug in relation to the time interval between taking the final dose and measuring the blood pressure (BP). DESIGN: After a 2-week wash-out period, hypertensive patients, recruited by cardiologists, received trandolapril 2 mg once daily in the morning for 4 weeks. METHODS: In order to assess compliance, each patient's supply of trandolapril capsules was presented in a pillbox that incorporated in its lid a microprocessor that recorded the date and time of each occasion that it was opened. BP was measured using validated semi-automatic devices, at the end of both the wash-out and the treatment period. RESULTS: A total of 590 patients entered the study. Compliance data were evaluable for 501 patients. Overall compliance, defined as the ratio of the number of openings recorded to the number of doses prescribed was less than 80, 80-100, and more than 100% in 17, 63 and 20% of patients, respectively. The average number (+/- SD) of missed doses was 4.5 +/- 8 (median 2). The average interval between successive openings was 25 h 07 min mean +/- 13 h (median 24 h). The average number of delayed doses (a delayed dose being defined as the box being opened 25-36 h after the previous occasion) was 5.6 +/- 3 (median 6). Patients living in the Paris area had more forgotten and delayed doses than those living in the provinces (7.9 versus 3.8 forgotten; P<0.0001 and 6.3 versus 5.5 delayed; P<0.005). Doses were forgotten and delayed more often during weekends than on weekdays. The greatest number of delayed doses occurred in those patients under 60 years of age (6.0 versus 5.2; P<0.01). Decreases in systolic blood pressure (SBP and diastolic blood pressure (DBP) were 20.3/12.8 mmHg, for patients whose final drug was taken on the same day as the BP measurement, and 18.9/11.2 mmHg for patients whose final dose was taken on the previous day. CONCLUSIONS: Electronic compliance monitoring allows refined analysis of the behaviour of hypertensive patients. In this study doses were missed and delayed frequently during the first month of treatment, depending on the patient's lifestyle.

Adolescent↗
PubMed1996

Comparison of home and clinical blood pressure measurements: clinical applications.

While measurement of blood pressure in the doctor's office remains the method of reference of the WHO, self-measurement yields complementary information, namely: measures outside the surgery, good estimation of the level of blood pressure at home from several day's data, better reproducibility related to standardized conditions of measurement imposed by the constraints of immobility and manoeuvre of the machine. The modalities of variation of BP by automeasure are known: diminution in the BP by automeasure of about 2 to 4 mm Hg between the first and the third measure performed at 1-min intervals, no significant evolution over 3 days and BP more elevated in the evening than in the morning. In comparison with the WHO data, the BP is significantly lower. Recently reference values have been proposed, giving as the upper threshold of normotension = 127/ 83 mm Hg and hypertension = 147/ 86 mm Hg. As regards diagnosis SM allows the identification of "white coat hypertension", and thus avoids treating these patients. The indirect prognostic value via target organ effect is under evaluation, and may be at the same level as ambulatory blood pressure measurement (ABPM). Given the utilisation of validated automatic machines and a rigorous methodology SM is beginning to be used satisfactorily in clinical trials. Numerous studies are still necessary in order to clearly define the place of SM in comparison to WHO and AMBP in the management of hypertension.

Antihypertensive Agents↗
PubMed1996

Global efficacy and tolerability of losartan, an angiotensin II subtype 1-receptor antagonist, in the treatment of hypertension.

Losartan is the first drug of a new therapeutic class, the angiotensin II (A II)-receptor antagonists, to be clinically studied and become available for the management of hypertension. Clinical experience with losartan from worldwide, double-blind, controlled studies has been obtained in more than 2900 hypertensive patients treated with losartan alone or in combination with hydrochlorothiazide, with 1700 patients receiving treatment for more than a year. The efficacy of losartan was evaluated in the young and old, in different degrees of hypertension, in blacks and nonblacks, and in patients with renal impairment. Tolerability parameters were assessed by subgroup as well. In dose-ranging studies, 50 mg once daily has generally been shown to produce near maximum effects and a dose of 100 mg does not produce additional effects. The efficacy of losartan (50 to 100 mg once daily) has been compared to atenolol (50 to 100 mg once daily), felodipine ER (5 to 10 mg once daily), and enalapril (20 mg once daily). The blood pressure-lowering effect of losartan was comparable to felodipine, enalapril, and atenolol. The efficacy of losartan was demonstrated using ambulatory blood pressure monitoring, which showed that losartan 50 mg once daily produced gradual reduction in blood pressure, providing 24-h control without affecting the body's circadian rhythm. In subgroups of study populations, no differences in efficacy were noted with respect to age, gender and the severity of hypertension. No initial dosage adjustment is necessary in the elderly and patients with renal impairment (even those on dialysis). Among blacks, the mean response of losartan was lower, which is not surprising given the lesser activation of the renin-angiotensin system in this population. A subgroup safety and tolerability analysis confirmed that there were no important differences in adverse events when assessed by age, race, or gender. The data obtained from controlled clinical trials conducted with losartan, the first A II-receptor antagonist, has shown that a single daily 50-mg dose provides adequate 24-h control of blood pressure in most patients with comparable efficacy to other classes and is well tolerated.

Adult↗
PubMed1996

[Diagnostic value of renal scintigraphy with MAG 3 and DTPA in the diagnosis of renal artery stenosis].

UNLABELLED: Angiography still remains the first line investigation to demonstrate a renal artery stenosis. We have evaluated the sensitivity and the specificity of renal scintigraphy in the diagnosis of renal artery stenosis using two technetium markers, MAG 3 and DTPA. PATIENTS: 45 hypertensive (HT) patients (WHO criteria) referred for investigation of renovascular hypertension according to the criteria of the AHA Scientific Council and were found to have a unilateral renal artery stenosis of varying severity. Age was 61 > +/- 13 years; sex-ratio F/M 21/24; creatinine < 150 mumol/l. There were non insulin dependent diabetics, and none had been treated with ACE inhibitors or diuretics for 15 days. Bilateral arterial stenosis was excluded a posteriori. METHODS: MAG3 and DTPA scintigraphy were performed one hour after a dose of 25 mg of captopril plus hydration with 500 ml of intravenous saline. Blood pressure was measured by dynamap every 15 min from minus one hour to the end of the study. The principle outcome measure was nephorgram phase and the secondary measure was the angiographic phase (two images per second). The two scintigraphy techniques were performed at a mean interval of 2.9 +/- 2.1 days. Digitized angiography via the arterial route was performed using left anterior oblique and right anterior oblique images. RESULTS: [table: see text] CONCLUSION: There was only one false positive scintigraphy result with a polar artery. In contrast 45% of unilateral stenoses were not diagnosed by scintigraphy. Both markers gave similar results even if subjectively the MAG3 images were of better quality. Analysis of the angiographic phase and of the size of the kidneys did not improve the diagnostic accuracy and could lead to false positive results.

Aged↗
PubMed1996

[Heart rate and blood pressure variabilities in mild to moderate hypertensive patients with or without left ventricular hypertrophy].

AIM OF THE STUDY: To compare heart rate (HR) and blood pressure (BP) variability in hypertensives with or without left ventricular hypertrophy (LVH). METHODS: Thirty-three mild to moderate hypertensive patients, mean age 45 +/- 15 years, underwent an echocardiogram, a 24 hr ambulatory BP monitoring (ABPM), a 24 hr ECG monitoring and a continuous BP recording over 15 minutes both in supine and standing positions, by using digital plethysmography (Finapres device). STATISTICAL ANALYSIS: non parametric tests. RESULTS: [table: see text] CONCLUSION: LVH is associated with a reduction in the markers of sympathetic activity and a decreased baroreflex sensitivity.

Adult↗
PubMed1996

[Short term blood pressure variability and baroreflex sensitivity in mild and moderate hypertensive patients "dipper and non dipper"].

AIM OF THE STUDY: To compare heart rate (HR) and blood pressure (BP) variability in hypertensive patients with or without a fall in BP during the night. METHODS: 33 mild to moderato hypertensive patients, mean age 45 +/- 15 years, underwent an echocardiogram, a 24-hr ambultory BP monitoring (ABPM), and a 24-hr ECG monitoring. In addition, a continuous BP recording over 15 minutes was performed between 9 and 11 a.m. both in supine and standing positions, by using digital plethysmography (Finapres device). STATISTICAL ANALYSIS: non parametric tests. RESULTS: [table: see text] CONCLUSION: In non dippers, morning BP and HR low-frequency oscillations are shifted to a lower level, as compared to dippers. This characteristic is associated with a reversed circadian pattern of sympathetic activity.

Adult↗
PubMed1996

[Short and long-term clinical tolerance of hypertensive treatment during the HOT study (Hypertension Optimal Treatment)].

International, prospective, randomized HOT study aims to determine the optimal BP level under treatment in order to reduce at the most the cardiovascular morbidity/mortality. Defined by randomization, the level to obtain is DBP < or = 80, 85, 90 mmHg. The treatment is started by felodipine 5 mg/day then, if necessary, a bitherapy is prescribed and then, if necessary, a tritherapy. 19,193 patients have been included (BP at randomization 170 +/- 15/105 +/- 4 mmHg). After 1 year treatment, it is possible to search for the influence on the clinical tolerance of sex, age, BP goal, geographic area, time and treatment. The percentage of patients with side effects by BP goals and by treatment type are, during the time and in different geographic areas, the following (NE/Northern Europe = Norway, Switzerland, Belgium, Hungary, Sweden, Denmark, Finland, The Netherlands, UK, Germany, Austria; SE/Southern Europe = Italy, Spain, Greece): [table: see text] The target BP and age don't nearly influence the clinical tolerance. The side effects reported by the physicians are more numerous at the treatment start than at longeur terme. That is due to the therapeutic modifications of the physicians or to a better acceptation of the drugs by the patients or to a real disappearance of the side effects. Reported side effects are more frequent in Southern Europe, France than Northern Europe and more frequent among women that men. The incidence of side effects is proportional to the number of prescribed drugs. Time and the number of antihypertensive drugs appear as the most important factors.

Age Factors↗
PubMed1996

[Treatment of hypertension with indapamide 1.5 mg sustained-release form: synthesis of results].

In accordance with international recommendations on the need to decrease doses of antihypertensive drugs, a low-dose (1.5 mg) sustained-release form of indapamide was developed so as to optimize the safety/efficacy ratio, while maintaining a once-daily administration. The new formulation ensures that the active ingredient release occurs in a sustained manner over 24 hours, with mean concentrations close to the maximal concentration over a prolonged period, while avoiding peak plasma concentrations. Clinical data were obtained mainly through two European multicenter, randomized, double-blind trials, totalling 690 patients. Firstly, the antihypertensive efficacy' of the new indapamide 1.5 mg form was demonstrated by measuring blood pressure 24 hours after the last drug intake, using a mercury sphygmomanometer; the equivalence of its antihypertensive efficacy with the immediate-release form of indapamide 2.5 mg was then verified. Biochemical safety data showed better acceptability with indapamide 1.5 mg with in particular a reduction of more than 50% of the number of patients with kalemia < 3.4 mmol/l; clinical safety data confirmed the good acceptability observed with the 2.5 mg immediate-release form of indapamide since many years, especially regarding glucose and lipid neutrality. In conclusion, the 1.5 mg sustained-release form of indapamide has an improved antihypertensive efficacy/safety ratio which is in accordance with international recommendations for the usage of low doses of antihypertensive drugs and diuretics in the first-line treatment of hypertension.

Adolescent↗
PubMed1996

[Evaluation of trough/peak ratio of indapamide 1.5 mg sustained-release form assessed by ambulatory blood pressure monitoring].

Because of the high variability of casual blood pressure measurements. ABPM has become a complementary clinical tool for evaluating antihypertensive treatment. Nevertheless, there is still a lack of practical guidelines to interpret the data. A review of the literature shows that ABPM efficacy data are analyzed differently, especially the trough-to-peak ratio proposed by the Food and Drug Administration. Published trough-to-peak ratios are widely disparate due to the diversity of the calculation methods which are most often not justified. Thus inappropriate comparisons of these results can easily produce incorrect conclusions. The aim of this review is to select, through the literature, basic methodological requirements commonly agreed on for accurate assessment of trough-to-peak ratio, and to apply them to the ABPM data on indapamide, a diuretic related to the thiazides. Six methodological requirements commonly agreed on at this time are the following: 1. study design: placebo-controlled study with a placebo run-in period; 2. patients selection: compliance with the study protocol, record obtained before and after treatment for each patient; 3. population analysis: whole and responder population: 4. quality control of the records: 5. placebo effect subtraction; 6. global and individual calculation with the indication of median values. Given that, no T/P ratio, especially for a diuretic, has yet been calculated according to these requirements, the above methodological points were taken into account for the T/P calculation of indapamide, from a placebo-controlled dose-finding study involving 285 patients.

Adult↗
PubMed1995

[Ambulatory measurement of blood pressure].

The advent of new techniques has greatly contributed to the development of ambulatory measurement as a noninvasive method for evaluating blood pressure. The technique implies use of a validated and reliable standardized apparatus. The operator must strictly comply with operating procedures, which must also be explained to the patient. Ambulatory measurement can be meaningful only if the results are compatible with reference values, which have now been established, and if the causes of possible error can be recognized and interpreted. Ambulatory blood pressure measurement has greatly improved our knowledge of physiological and pathological variations over the circadian cycle including day/night variability and the effects of psychosensorial stimulation. Diagnostic indications are clearly identified and include borderline hypertension suspected but not identified after about 3 months, the white coat effect, severe hypertension when modifications in the circadian cycle are suspected, paroxysmal hypertension, suspected pheochromocytoma, and gravid hypertension or an inversion of the circadian cycle possibly preceding an episode of eclampsia. There are also a certain number of particular indications in patients with degenerative or primary conditions affecting their autonomy. The true prognostic value of these recordings was recognized several years ago and has been confirmed by clinical trials. For example, the white blouse effect has no significant implication in terms or predicting less favourable morbidity or mortality. Finally, ambulatory blood pressure measurement has been definitively shown to be a valid method for evaluating the therapeutic effect of an anti-hypertensive drug in a given patient, especially when resting levels are questioned. For therapeutic trials, ambulatory measurements serve as a reference to evaluate the effect of treatment on the circadian cycle. Peak/dip levels can thus be determined in comparison with the residual effect of the drug. A large number of studies remain to done to identify the full potential of this method.

Blood Pressure↗
PubMed1995

Diagnostic and prognostic value of exercise testing.

Measuring blood pressure during exercise under a standard protocol could be a useful diagnostic method in high-risk patients and in borderline hypertensive subjects. It may also serve as an adapted test for hypertensive subjects undergoing physical activity at work or at leisure time with a particular cardiovascular work load. It can be used as a method of assessment to confirm the efficacy of an antihypertensive drug, and for prognostic evaluation of cardiovascular risk in terms of morbidity and mortality. An exercise blood pressure profile does not provide information about blood pressure during activities of daily living. For this purpose, ambulatory blood pressure measurement appears to be more relevant.

Blood Pressure↗
PubMed1995

Examination of variability in arterial blood pressure at rest using spectral analysis in hypertensive patients.

INTRODUCTION: We hypothesize that in essential hypertension sympathetic nervous activity is related to the development of left ventricular hypertrophy, which can be regarded as a measure of the severity of hypertension. METHODS: Using spectral analysis, we studied the short-term variability in resting blood pressure and heart rate in essential hypertensive subjects. We measured blood over 10 min using a Finapres in 88 subjects after 20 min rest. We performed echocardiography to evaluate left ventricular hypertrophy and thereby identified three groups: 23 control subjects (group I), 29 hypertensive subjects (World Health Organization criteria) without left ventricular hypertrophy (group II) and 36 hypertensive subjects with left ventricular hypertrophy (group III). None had been treated for hypertension before the study. RESULTS: The variability in blood pressure over a low-frequency period considered to be a marker of sympathetic activity was significantly increased in group II compared with groups I and III (analysis of covariance taking into account blood pressure and age). The variability in heart rate was similar in groups II and III, but both groups had a significantly reduced variability in heart rate compared with group I. CONCLUSION: These data, which examine globally, using a non-invasive method, all neurohormonal factors associated with the development of left ventricular hypertrophy, demonstrate that, in the time course of hypertension, low-frequency oscillations in blood pressure and heart rate are shifted to a lower level, presumably reflecting altered function of the sympathetic nervous system. We suggest that spectral analysis of blood pressure at rest in hypertensive patients can lead to complementary information to single measures of blood pressure and detect differences in the cardiovascular regulatory system.

Age Distribution↗
PubMed1995

[Reproducibility of echocardiographic parameters by automatic detection of contours in hypertensive patients].

The reproducibility of automatic outline detection is a echocardiographic reproducibility which has been poorly evaluated in patients with cardiomyopathy. Two independent observers identified the systolic surface and mid and end diastolic surfaces of 27 hypertensive patients, who had been referred to the laboratory for the measurement of left ventricular mass. Each observer examined on two occasions all parameters and all parameters were measured at least 2 hours apart. The coefficient of variation (CV) expresses the reproducibility of each measurement. The intra observer was 10 to 15% and the inter observer 15 to 22% for the measurement of surface area. The coefficient of variation is regularly greater than 20% for measures of maximum speed, which characterise surface changes in diastole. The automatic detection of contours is a echocardiographic tool whose potential is great for evaluating left ventricular function but the current versions can only be applied to very selective group of patients depending on the quality of their echographic window for acoustic quantitation. This technique is very operator dependent, in particular as regards setting the gains and this explains its poor reproducibility and its limited interest in daily clinical practice.

Adult↗
PubMed1995

[Paradoxic changes in the morphology of blood pressure wave in hypertensive heart diseases].

UNLABELLED: The objective is to study the relation between left ventricular (LV) effect (index of LV mass (LVMI) and index of inotropic state) and arterial compliance determined but the proximal aortic pressure waveform and by the carotid femoral pulse wave velocity. MATERIAL: 72 untreated hypertensives; systolic blood pressure (SBP) 170 +/- 18 mmHg/diastolic blood pressure (DBP); heart rate: 69 +/- 9 batt/min; age: 48 +/- 13 years; duration of hypertension 4.6 +/- 4.8 years; sex ratio 49 M/23 F. OBJECTIVE: Proximal aortic pressure waveform (carotid artery) was studied by applanation tonometry. We derived the index of amplification (AI = Pmax-Pinflex)/PP, %), pulse pressure (PP), the maximum rate of rise of pressure (dpdt, mmHg.s-1). Echocardiography was used to define the index of LV mass (VLMI), end systolic volume (ESV), end systolic stress (ESS), myocardial contractile force (ESS/ESV), inotropic state (SBP/ESV). Carotid-femoral pulse wave velocity was determined by mechanogram (PWW m/s). RESULTS: 1. Relationship of physiological changes of AI and SDA to age, height, PP, DBP, PWV, and LVMI were observed in table I (r-Pearson cor. coefficient, * < p 0.05; **: p < 0.001). [table: see text] In stepwise regression analysis, even allowing for BP, age, and height, there was no relationship between LVMI and the index of aortic amplification (AI). 2. In the subjects with LVH (LVMI > 110 g/m2) we found a bimodal distribution of the AI which defines two groups in agreement with the Murgo Classification. [table: see text] In type B, where AI is weaker, the indices of aortic rigidity are reduced, there is an increased ESS and a paradoxal fall in LV performances. CONCLUSION: Analysis of proximal aortic pressure waveform don't allow to predict index of LV mass. These results suggest that in the sphere of LV aortic compiling the reduction of LV function contributes to modification of the BP waveform with diminution of dpdt and the index of amplification.

Adult↗
PubMed1995

[Ambulatory blood pressure monitoring and clinical trials].

Ambulatory blood pressure monitoring (ABPM) is now widely used for the assessment of antihypertensive drugs. This procedure may be used in phase II studies in dose-ranging evaluations as well as in phase III in order to assess the drug efficacy in the patient's natural environment. The increase in the reproducibility related to the repetition of blood pressure measurements by ambulatory monitoring may improve the accuracy of the trial and minimize the numbers of subjects required. Placebo fails to lower ambulatory blood pressure in almost all studies. Nevertheless, placebo is always necessary in clinical studies with ABPM at least for the pre-inclusion phase and in order to study the peak-trough ratio. This ratio may be accurately assessed by ABPM. Finally, ABPM may be useful to rule out "white coat" responders, who are not really hypertensive patients.

Antihypertensive Agents↗