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Biomedical subjects

E Billaud

Publications and source records attributed to E Billaud.

59 records · Page 4Linked to original sources
PubMedDate not supplied

Noninvasive measurement of medium-sized artery intima-media thickness in humans: in vitro validation.

Recent research in ultrasound technology has led to the development of a high-resolution echo-tracking device. The present study was performed to evaluate the accuracy in the measurement of human radial artery intima-media thickness with this new device. We determined the correlation between histological and ultrasonic measurements of intima-media thickness in 15 radial artery segments obtained from the distal end of the wrist-elbow harvest for coronary bypass grafting in patients with coronary heart disease. For arterial intima-media thickness, a positive correlation was observed between ultrasonic and histological measurements (r = 0.618; p < 0.014), and the difference between ultrasound and histology measurements was 41 +/- 66 microns, with the higher measurements found by the ultrasonic device. In a subgroup of 11 patients, we determined the correlation between in vivo ultrasonic measurements of radial artery intima-media thickness at the preoperative stage and in vitro ultrasonic measurements of intima-media thickness obtained postoperatively in the same arterial segments. Internal diameter was larger in vivo than in vitro, and intima-media thickness was smaller in vivo than in vitro. The cross-sectional area of the arterial wall was calculated from internal diameter and intima-media thickness. In vitro wall cross-sectional area was correlated with in vivo wall cross-sectional area (r = 0.929; p < 0.0001). Repeatability of in vivo intima-media thickness measurements was investigated in 10 subjects through the calculation of the repeatability coefficient as defined by the British Standards Institution.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation Studies as Topic↗
PubMedDate not supplied

Progression to AIDS or death as endpoints in HIV clinical trials.

PURPOSE: To assess progression to AIDS or death from month 4 after a protease inhibitor-containing regimen is initiated in a cohort of 1,281 patients. METHOD: We used Kaplan-Meier estimates of probability of clinical progression. RESULT: At month 4, most patients had an HIV-1 RNA plasma value below 500 copies/mL (78%) and a CD4 cell count above 300 cells/mm(3) (62%). Starting from month 4, clinical progression at 1 and 2 years of follow-up was low (<3% at 1 year) in patients with HIV RNA <500 copies/mL or 500-10,000 copies/mL and in patients with CD4 between 50 and 300 cells/mm(3) or >300 cells/mm(3). A higher risk of clinical progression (> or =10% at 1 year) was evidenced only in patients with poor response to antiretroviral therapy, that is, with CD4 <50 cells/mm(3) or CD4 between 50-300 cells/mm(3) together with an HIV RNA >10,000 copies/mL. CONCLUSION: In patients currently on antiretroviral therapy, clinical trials with clinical progression as endpoint are almost not feasible, except in patients with a poor immunovirological response to first- or second-line HAART.

Anti-HIV Agents↗
PubMedDate not supplied

[Biochemical diagnosis of pheochromocytoma and neuroblastomas].

Pheochromocytoma and neuroblastoma are distinct tumours, but their biological diagnosis is based on secretion increase of one or several catecholamines. Assays have to be very sensible and specific for an early diagnosis. 24 hours urinary catecholamines and metabolites are currently measured, but technical improvements permit plasma metanephrine assay, an excellent indicator of pheochromocytoma. HPLC coupled to electrochemical detection represents the most efficient methodology. After a review of urinary and plasma assay methods, the authors show usual values of catecholamines, metanephrines, HVA and VMA, according to ages, and give examples of results encountered in classical or not tumours and in falsely positive cases. Urinary metanephrine assay is the most sensible and specific in biological diagnosis of pheochromocytoma, while catecholamines and VMA assays lack of sensibility. Results have to be given by 24 hours and by creatinine ratio. Metanephrine assay can be performed also in plasma and exhibits the same interest. However, in urine as in plasma, in case of renal failure, results cannot be interpreted. Neuroblastoma biological diagnosis is based classically on HVA, VMA, and dopamine assays, nowadays only in 24 hours urine (or in urinary micturition for screening), and results are also expressed as creatinine ratio. But even if several assays are advisable, 5% of the neuroblastoma cases do not produce increased catecholamine values. In some cases, metanephrine assay could be of interest. After the age of 12 months, clinical expression of neuroblastoma is dramatic in 70% of cases. So, a biological screening has been experimented in several countries including France. A French translation of the consensus conference report (1998) is appended, which shows the complexity of neuroblastoma screening. Now, there is no evidence that early tumour detection by screening lessens the mortality rate, but a weak benefit is not excluded.

Adolescent↗
PubMedDate not supplied

[Calcium antagonists and arterial hypertension].

The pharmacological class of calcium channel antagonists (CCA) is, with beta-adrenergic antagonists, diuretics, converting enzyme inhibitors and alpha-adrenergic antagonists, one of the first line monotherapies of essential hypertension, according to the recommendations of the "Fifth Joint National Committee on Detection, Evaluation and Treatment of Hypertension". CCA have several advantages for the treatment of hypertension: the blood pressure lowering effect is due to a reduction of total peripheral vascular resistance, which are primarily abnormally increased in hypertension; the antihypertensive efficacy of CCA is comparable to that of other commonly used antihypertensive drugs; CCA induce a significant regression of left ventricular hypertrophy, a factor of morbidity and mortality which is considered to be independent of the level of mean arterial pressure; CCA have vasodilating properties on the coronary circulation; CCA are generally well tolerated, from both clinical and biological points of view. The challenge for CCA concerns three domains related to the morbidity/mortality of hypertension (coronary and cerebrovascular events) a better antihypertensive efficacy for the whole period of 24 hours, a better prevention of cerebrovascular events and an effect on the development of atherosclerosis.

Antihypertensive Agents↗