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Biomedical subjects

B Chamontin

Publications and source records attributed to B Chamontin.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Should arterial hypertension in sleep apnea syndrome be stressed?].

The frequent association of sleep apnea syndrome and essential hypertension led to think of sleep apnea as an etiology of hypertension, especially as a good correlation has been found between the severity of both diseases. Moreover, treating the apnea syndrome results in a decrease of blood pressure. The aim of our study is to depict the outlines of a severe hypertensive individual with sleep apnea by comparing 9 men primarily referred to the hypertension clinic with refractory hypertension and finally found to have sleep apnea (study group) to 23 men whose diagnosis of sleep apnea was made in the pulmonary unit (controls). Fifteen of these were hypertensives. Mean age of the study group was 47 +/- 7 years vs 60 +/- 11. Controls were less overweighted: BMI = 33 +/- 6 kg/m3 vs 39 +/- 5. Mean blood pressure was 171 +/- 16/107 +/- 4 mmHg in the study group vs 157 +/- 19/92 +/- 12 mmHg in controls. Prevalence of glucose metabolism disorders was significantly greater in the study group: 6 patients with maturity onset diabetes and 3 with proven glucose intolerance, vs respectively 4 and 6 controls. Triglycerides were elevated in both groups whereas mean cholesterol was slightly above normal values. Six patients of the study group could have an echocardiogram which showed left ventricular hypertrophy (mean left ventricular mass index = 206 +/- 31 g/m2 after the Penn convention).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Ambulatory blood pressure in the young adult with hypertension history during childhood].

The tendency of subjects to maintain their relative position within the distribution of blood pressure (BP) has been defined as "tracking". Regarding this phenomenon, the purpose of the study was to evaluate the interest of ambulatory BP monitoring (ABPM) in the assessment of arterial hypertension in young adults (YA) with childhood hypertension history (CHH). 52 subjects, 20.1 +/- 2.4 years old, 26 men, 26 women issued from a cohort of 150 children with high BP levels (greater than 97.5 th percentile) during their infancy (school check-up), were included in the study. An ABPM was performed with space-labs system 90202 from 8 a.m. to 6 p.m., measurements every 15 minutes (37.6 +/- 7.4 readings). Left ventricular mass index (LVMI) was determined with echocardiography, (Penn convention). Office BP, measured with mercury apparatus in lying and standing position, was respectively, 131.0 +/- 14.6/81.9 +/- 9.7 and 130.1 +/- 14/86.6 +/- 9.9. According to JNC 1988, this casual BP identified 40 normotensives (NT), 9 borderlines (BL) and 5 hypertensives (HT); 10 of them had a "high normal" diastolic BP (85-90 mmHg) ABP recordings of the study group were compared to day-time reference values of NT. Three subgroups are individualized: G1 NT, G2 HT, G3 BL. [table; see text] *p: less than 0.001; p: less than 0.01. Wall thickness (WTh) and LVMI were significantly higher in hypertensives (G2 + G3) than in normotensives (G1): [table; see text] There was a significant correlation between LVMI and mean systolic ABP (p less than 0.01: r = 0.44), but not with office SBP.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Prevention of stress-induced hypertension in hypertensive patients.

The aim of the study was to assess the course of the alerting reaction during an effective antihypertensive treatment, and to discuss its interference with the conduct of therapy. In 28 patients suffering from mild to moderate hypertension, the basal blood pressure was measured in an outpatient clinic according to a standardized procedure, first by a nurse, then by a 12-min recorded monitoring, and then by a physician using a mercury sphygmomanometer with the patient in the upright and then the supine position. In comparison with the monitoring (mean values recorded at 6, 9, and 12 min), there was a significant increase in diastolic and systolic blood pressure taken by the nurse and by the physician, which diminished at the end of the visit with the physician. Patients then received 10 mg of bisoprolol each morning and presented again on day 30 and day 60, following the same procedure and under identical conditions. Despite the desired antihypertensive effect, the alerting reaction persisted at each visit up to the end of the study, being unchanged in the case of the systolic blood pressure and accentuated in the case of the diastolic blood pressure. Our results confirm those of previous investigations showing that even an effective antihypertensive therapy is unequivocally associated with a persisting alerting reaction irrespective of the antihypertensive drug applied. Thus, patients may be exposed to the potential risk involved with false failures and unnecessary overtreatment. The physician must compare his or her own measurements with readings made outside the consulting office and must program ambulatory blood pressure monitoring in the case of discrepancy. This is a suitable means of confirming and validating blood pressure measurements, as this method does not record the alerting reaction.

Adrenergic beta-Antagonists↗
PubMed1990

[Outcome of "white coat reaction" induced by nurse and physician in patients with hypertension treated with a beta blockader (bisoprolol)].

The aim of the study was to assess the evolution of Alerting reaction (AR) under beta blocker treatment and to discuss its incidence on the management of arterial hypertension (AH). In 28 patients (pts), 19 men, 9 females, 46 +/- 12 years old, suffering from a mild to moderate AH, blood pressure (BP) was measured, according to a ritual circuit by a nurse (N), then a 12-minutes recorded monitoring, then a physician (Ph) using a mercury sphygmomanometer in upright, then in supine position at the end of the visit (165 +/- 18/108 +/- 13 mmHg, 161 +/- 14/100 +/- 9 mmHg). Pts received a cardioselective beta blocker, bisoprolol (B), 10 mg once daily and BP was evaluated after 1 and 2 months (D30; D60) under identical conditions. When compared to monitoring BP, there was a significant increase in systolic (S) and diastolic (D) BP, taken by the nurse and the physician, attributed to AR (delta SBP; delta DBP). Under B, AR remained unchanged, even increased regarding upright DBP at D30, D60 in spite of its efficacy: (formula; see text) The study demonstrates that there is no incidence of beta blocker on alerting reaction and that AR must be considered to evaluate the treatment and avoid an unnecessary or overtreatment. In case of discrepancies, it is suggested to perform an ambulatory BP monitoring.

Adrenergic beta-Antagonists↗
PubMed1990

[Ambulatory blood pressure in hypertension with dysautonomia].

The purpose of the study was to evaluate the interest of ambulatory blood pressure (BP) recording (ABPR) in the management of arterial hypertension (AH) with dysautonomia. The study concerned 8 hypertensive patients (pts), 5 men, 3 females 52 +/- 10 years old, with orthostatic hypotension (OH): BP was 162 +/- 19/87 +/- 16 mmHg and 129 +/- 15/76 +/- 8 mmHg in lying and standing position respectively. In two cases AH was associated with a central degenerative disorder whereas the six other pts had a diabetic dysautonomia: bad metabolic control (HBA1c 14.4 +/- 2.7%), and incipient or over nephropathy (4 pts). ABPR was performed in all pts during 24 hours (space-labs system). In these hypertensive pts with OH, the mean 24 hour-BP was surprisingly normal at 128 +/- 11/76 +/- 6 mmHg. ABPR demonstrated the loss of nocturnal decline in BP: diurnal and nocturnal BP were respectively 125 +/- 13/74 +/- 6 mmHg and 133 +/- 16/78 +/- 10 mmHg (NS). 6 of 8 pts had an increase in BP at night resulting for the population (n = 8) in a nocturnal increase (%) of + 5.6%, this pattern widely differs from controls--13%. The decrease in heart rate during sleep was blunted but significant from 89 +/- 9 b/min to 81 +/- 9 b/min (p 0.01). Diurnal and nocturnal BP variability (V), assessed by variation coefficient were not significantly different: SBP-V was 10.3 +/- 6.4% day and 12.3 +/- 4.2% night, DBP-V 7.5 +/- 6.3% day and 12.5 +/- 3.1% night.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Neurogenic arterial hypertension in humans].

The purpose of this study was to investigate baroreflex activity in hypertensive patients with orthostatic hypotension (OH) due to sinoaortic baroreceptor denervation. The study concerned 3 patients (pts), 58-63 years, mean age 60.6 +/- 2 with both arterial hypertension (paroxysms recorded at 250/130 mmHg) and OH. They received radiation therapy to the entire cervical area for neoplasm, 9.6 +/- 2.8 years ago and had a carotid murmur without significant stenosis. Every pt had a severe and symptomatic OH: blood pressure (BP) and heart rate (HR) were respectively 163 +/- 17/105 +/- 7, 82 +/- 5 b/mn in lying position and 82 +/- 16/53 +/- 9 mmHg, 99 +/- 1 b/mm in standing position. The standing-induced increase in HR was lower (delta HR = + 17.3 b/mn) than expected; atropine (0.02 mg/kg) infusion and cold pressor test were ineffective; the massage of sinocarotid receptors induced a slight decrease in HR (delta HR = - 8 b/mn) and BP was not modified by Valsalva's maneuver. Infusion of norepinephrine (0.016 mg/mn) performed in one pt, increased BP without effect on HR. Platelet alpha 2-adrenoreceptors (alpha 2AR) evaluated by (3H) Yohimbine binding showed a significant increase in alpha 2AR number (Bmax), without any significant change in affinity (KD) when compared with normotensive and essential hypertensive pts: (table; see text) This study described an unusual etiology of a paroxysmal hypertension with orthostatic hypotension, demonstrated the impairment of baroreflex activity and suggested the potential interest of platelet alpha 2 adrenoceptors measurement to evaluate sympathetic tone in these patients.

Blood Pressure↗
PubMed1989

[Effect of a calcium inhibitor, nicardipine, on aldosterone secretion in primary hyperaldosteronism].

The purpose of the study was to evaluate the effects of a dihydropyridine calcium antagonist, nicardipine (N), on blood pressure (BP) and aldosterone secretion in hypertensive patients (pt) with primary aldosteronism. The study concerned 8 pts, mean age 55.6 +/- 7.7 years, 1 pt with aldosterone-producing adenoma (APA) and 7 pts with idiopathic aldosteronism: plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were respectively 0.30 +/- 0.2 ng/ml/h) and 314 +/- 109 pg/ml. Acute administration of 12 mg of nicardipine during 90 mn (three periods of N infusion during 30 mn: 0.4 mg/mn-5 mn; then 0.08 mg/mn-25 mn) significantly decreased BP, with an increase in heart rate (HR); the levels of PAC were significantly reduced with a slight but not significant increase in PRA, 60 mn after N: (table; see text) N decreased also PAC in the pt with APA [600 to 410 pg/ml] but did not improve hypokalemia (3.1 vs 3.3 mmol/l, n = 8 N.S.). In contrast, PAC levels were not modified 2 hours after acute oral administration of captopril (1 mg/kg): 302 +/- 164 pg/ml vs 332 +/- 191 pg/ml (NS). This study demonstrated the antihypertensive efficacy of acute infusion of nicardipine in primary aldosteronism; the decrease of PAC under this calcium antagonist suggested its potential interest in the management of idiopathic aldosteronism.

Aged↗
PubMed1989

[Usefulness of a percutaneous endoprosthesis in the treatment of renal artery stenoses].

In approximately 10 p. 100 of the cases stenosis of the renal artery cannot be satisfactorily dilated by percutaneous transluminal angioplasty (PTA), and about 10 p. 100 of the patients successfully dilated have short-term restenosis. The excellent results obtained experimentally and clinically with the implantation of percutaneous intravascular stents have prompted us to use this material in the renal arteries. Stents were implanted in 10 patients who were followed up for periods of 1 to 16 months. Eight of them had restenosis after PTA; five of these stenoses were due to atheroma, 2 to fibromuscular dysplasia and 1 to Takayasu's disease. Two patients were implanted from the start owing to the insufficient results of PTA. Seven patients had severe arterial hypertension most probably of renovascular origin. Three patients had hypertension associated with moderate renal failure. Implantation was performed after a previous PTA. Adjuvant treatments and monitoring were the same in every case with, in particular, radiological control examination after one and six months. The implantations themselves were uneventful, and immediate control showed almost perfect anatomical restoration in all patients. On subsequent controls, arterial patency was preserved in all but one case. All patients showed significant clinical improvement. These results are most encouraging. They suggest that intravascular stents constitute an interesting solution when PTA is insufficient in the treatment of renal artery stenosis.

Adult↗
PubMed1988

Platelet alpha 2- and leucocyte beta 2-adrenoceptors in phaeochromocytoma: effect of tumour removal.

Platelet alpha 2- and leucocyte beta 2-adrenoceptors (as well as noradrenaline and adrenaline plasma levels) were studied in five patients with confirmed phaeochromocytoma using tritiated yohimbine and iodated cyanopindolol, respectively, before and after tumour removal. Patients with phaeochromocytoma had a lower leucocyte iodated cyanopindolol binding than control subjects, but no change in platelet tritiated yohimbine binding. Plasma catecholamine levels were higher than controls. Tumour removal induced a return to normal values of leucocyte iodated cyanopindolol binding and a decrease in plasma catecholamine levels. These results underline the potential interest of leucocyte beta-adrenoceptor quantification in the diagnosis and the follow-up of phaeochromocytoma. Pharmacologically, they show that down-regulation occurs in vivo for leucocyte beta 2-adrenoceptors but not for platelet alpha 2-adrenoceptors.

Adrenal Gland Neoplasms↗
PubMed1988

[Value of the study of circulating adrenergic receptors in the diagnosis and surveillance after surgery of pheochromocytoma].

The purpose of the study was to investigate leukocyte beta adrenoceptors and platelet alpha 2 adrenoceptors in pheochromocytoma. The study concerned nine hypertensive patients, five men and four women (aged 42 +/- 8 years) with a pheochromocytoma demonstrated by high levels of urinary catecholamines and radiological data. Catecholamine plasma levels, assayed by HPLC were wide-ranging: 10.7 to 172.8 nM for noradrenaline and 0.7 to 3.9 nM for adrenaline. In each case the number of leukocyte beta adrenoceptors sites (measured with 125 I-cyanopindolol) significantly decreased: Bmax was 20.6 +/- 2.8 versus 48.5 +/- 1.5 fmol/mg protein in controls (p less than 0.05). In contrast, the number of platelet alpha 2 adrenoceptors sites (measured with 3H-yohimbine) was not modified: 206 +/- 22.6 versus 186.0 +/- 12.1 fmole/mg protein in controls. There was no change in affinity constant (Kd), neither for beta nor alpha2 adrenoceptors. After tumor removal, there was a significant increase in beta adrenoceptor number. We conclude that down regulation occurs in vivo for beta adrenoceptors but not for alpha2 adrenoceptors and that the decrease in leukocyte beta adrenoceptor number is an interesting and suitable index in the management of pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1987

Experimental and clinical approaches to treatment of hypertension by dopamine receptor agonists.

The action of several dopamine agonists on blood pressure was investigated. In dogs, apomorphine induced a decrease in blood pressure and an increase in heart rate. These effects were suppressed by intravenous haloperidol or phentolamine. Intravenous but not intracisternal domperidone suppressed the hypotensive responses elicited by intravenous or intracisternal apomorphine. Furthermore, the hypotensive effect of bromocriptine or apomorphine was abolished in adrenal demedullated dogs. Apomorphine and bromocriptine decreased adrenal catecholamine levels. In men, the acute hypotensive property of apomorphine (but not the long term effect of bromocriptine) was suppressed by pretreatment with domperidone. In hypertensive Parkinsonians, bromocriptine reduced blood pressure, induced an increase in inulin clearance, a decrease in plasma creatinine concentration and in renal vascular resistances. These results suggest that dopamine agonists (like apomorphine or bromocriptine) reduce blood pressure through both a decrease in sympathetic tone and an improvement in renal function. However, the mechanism of the acute and long term hypotensive effects could be different only involving peripheral mechanisms after acute administration and both peripheral and central structure under chronic treatment. In addition, preliminary results suggesting the potential interest of dopamine antagonists in the management of orthostatic hypotension are discussed.

Dopamine↗
PubMed1987

[Influence of angiotensin on the secretion of aldosterone in idiopathic hyperaldosteronism].

The purpose of study was to investigate the role of angiotensin II in idiopathic primary aldosteronism (IPA) and to evaluate the interest of angiotensin converting enzyme inhibitors (ACEI) in its management. The study concerned 10 hypertensive patients, mean 49 +/- 11 years with idiopathic primary aldosteronism due to bilateral adrenal hyperplasia: plasma renin activity (PRA) less than 1.5 ng/ml/h and plasma aldosterone (PA) greater than 25 ng/100 ml. Adrenal venography and adrenal vein aldosterone levels demonstrated bilateral hyperplasia. PRA and PA were evaluated in recumbent position, then after 4 hours in upright posture. The next day, a "captopril screening test" was performed with PA assays before and three hours after a single oral administration of captopril (1 mg/kg). Upright PRA and PA were slightly increased and acute administration of captopril reduced significantly PA levels in all patients. Blood pressure (BP was unmodified under captopril. These hormonal results demonstrated that adrenal glomerulosa remained sensitive to low concentrations of angiotensin II, and underlined the potential interest of ACEI in the management of IPA. Brown R. demonstrated already an increase of adrenal sensitivity to angiotensin II infusions, and isolated an aldosterone-stimulating factor (ASF). Plasma aldosterone levels were related to increased ASF concentrations but there was no link between PRA and ASF. Carey R. suggested that ASF acts through an increase of the sensitivity of aldosterone production to angiotensin II.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗