PubMed Health⌕ Search

Biomedical subjects

F Masson

Publications and source records attributed to F Masson.

At least 19 recordsLinked to original sources
PubMed1992

Atrial natriuretic peptide during water deprivation or hemorrhage in rats. Relationship with arginine vasopressin and osmolarity.

The concentrations of atrial natriuretic peptide (ANP) in atria, hypothalami and plasma were investigated in relation to the variations of the plasma endogenous immunoreactive arginine vasopressin (Ir-AVP) during water deprivation or hemorrhage in normal conscious Wistar rats. Furthermore, the in vitro and in vivo effect of extracellular hyperosmolarity on ANP release from right atrium and hypothalamus was examined. Water deprivation elevated circulating immunoreactive ANP (Ir-ANP: pg/ml) to 153 +/- 7 (24 h); 174 +/- 1 (48 h) from the control level (109.6 +/- 7.8). This increase in Ir-ANP concentration which correlated with atrial (r = -0.93) or hypothalamic (r = -0.87) Ir-ANP content decrease, was associated with significantly enhanced levels of plasma Ir-AVP, plasma sodium, osmolarity and hematocrit. An acute volume depletion by hemorrhage significantly reduced plasma Ir-ANP (67 +/- 8.4 pg/ml) from the sham operated level (140 +/- 18 pg/ml). Plasma Ir-AVP was elevated dramatically (207.4 +/- 53.4 pg/ml) compared with the sham operated level (8.8 +/- 2.6 pg/ml). These results, indicating the lack of correlation between plasma Ir-ANP and Ir-AVP in vivo, suggest that the ANP secretion, which is regulated mainly by plasma volume, may be modulated by a change in plasma osmolarity. Extracellular hyperosmolarity stimulated the ANP release from superfused sliced normal rat atria and hypothalami.

Animals↗
PubMed1992

Endothelin in chronic renal failure.

The aims of the present study were to determine plasma endothelin (ET) in chronically uraemic patients, the renal clearance of endogenous ET in normal dog and man, and the effect of acute volaemic expansion on ET. The mean plasma ET concentration in haemodialysis patients was 57.5 +/- 5 pg/ml before haemodialysis and remained unchanged at 52.5 +/- 5 pg/ml after haemodialysis. They were thus significantly elevated both before and after haemodialysis (P less than 0.01) compared with plasma ET in normal subjects of 20.8 +/- 0.8 pg/ml. There was no evidence of ET clearance across the cuprophane membrane of the dialyser. Resting plasma ET values in the 15 non-dialysed uraemic patients ranged between 20 and 52.5 pg/ml (mean 38.2 +/- 2.3 pg/ml), significantly greater than those observed in controls (P less than 0.01). In CAPD patients, plasma ET was also significantly (P less than 0.01), elevated (63 +/- 10 pg/ml) when compared to controls, and similar to those observed in patients before haemodialysis. In dogs, mean ET did not diminish between the aorta and the renal vein (28.1 +/- 1 versus 28.4 +/- 2 pg/ml). In man mean ET did not significantly decline between the renal artery and the renal vein (17 +/- 3 to 13 +/- 0.8 pg/ml). In the seven healthy subjects who received 2000 ml of isotonic saline intravenously ET remained unchanged (24 +/- 2; 23 +/- 1 and 23 +/- 2 pg/ml before and 1 and 2 h after starting hydration respectively). We have thus shown that plasma ET is elevated in patients with chronic renal failure especially those on dialysis and CAPD.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Oncocytic tumors of the kidney apropos of 2 cases. Actualities in the preoperative diagnosis and therapeutic attitude].

The authors report two cases of renal oncocytoma treated by radical nephrectomy. There is still a controversy because the term oncocytoma is used for all tumors containing oncocytes, either true oncocytoma or adenocarcinoma with oncocytoma cells. The main problem is to distinguish, prior to surgery, between renal oncocytoma, a tumor with benign evolution, and renal adenocarcinoma with oncocytes, to offer conservative surgery for renal oncocytoma.

Adenoma↗
PubMed1992

Posttraumatic disablement: a prospective study of impairment, disability, and handicap.

This study was designed to evaluate both the frequency and the course of impairments, disabilities, and handicaps resulting from trauma. It was conducted in Aquitaine, France, on a sample of 1005 trauma patients (mean ISS, 10.5 +/- 0.3) in which severe trauma (ISS > 25) was rather overrepresented (169 of 1005). A prospective follow-up of disablement according to the WHO classification was based on medical examinations performed 6 and 12 months after the trauma. Of 664 survivors reviewed at 6 months, the findings were cross tabulated with Injury Severity Score (ISS) and age. There was a good relationship between ISS and the mean length of stay in the hospital (r = 0.46; p < 0.001), the duration of rehabilitation, and the time away from work or school. Out of this sample of 1005 patients with rather major injuries, 73% of the survivors suffered from at least one impairment, with a consistently lower frequency in children whatever the severity. At least one disability was encountered in 52.3% of these patients depending on both ISS and age. Handicap was noted in at least 26% of the cases. Between the sixth month and the end of the first year, the minimal handicap regression was 35.8%, whereas the minimal regression of the disability rate was 19.5%. The best improvement was observed essentially in the low ISS categories. Whereas for minor trauma the course of disablement seems to be fixed 1 year after the injury, such is not the case for severe trauma.

Absenteeism↗
PubMed1991

Effects of arginine vasopressin and extracellular osmolarity on atrial natriuretic peptide release by superfused rat atria.

This study investigated the characteristics of atrial natriuretic peptide (ANP) release from superfused sliced atria and ventricles of rats. Right atria spontaneously released more immunoreactive ANP (Ir-ANP: pg/min per mg tissue) (32 +/- 3) than did left atria (11 +/- 2) or right ventricles (1.5 +/- 0.5). Addition of 10(-9) to 10(-5) M of arginine vasopressin (AVP) to the superfusing fluid or increasing its osmolarity (290 to 490 mOsM) resulted in a significant increase of the Ir-ANP outflow from right atria. The effect of AVP was prevented by a specific V1 receptor antagonist, ([d(ch2)5Tyr(Me)]AVP). Superfusion with indomethacin (10(-5) M) did not alter spontaneous release but inhibited the peak levels of Ir-ANP induced by AVP (10(-5) M). Moreover, DDAVP, a specific V2 receptor agonist, did not induce Ir-ANP release. Ca(2+)-free medium alone or plus 1 mM EGTA induced a significant increase in basal Ir-ANP outflow. The Ir-ANP released chromatographed similarly to the standard alpha-rANP. These results suggest a specific stimulatory effect of AVP and osmolarity and a negative influence of extracellular Ca2+ on atrial spontaneous Ir-ANP release. It appears that the effect of AVP could be mediated by prostaglandin synthesis.

Animals↗
PubMed1991

[Plasma catecholamines in brain death].

The purpose of this study was to find out whether a severe fall in plasma catecholamines levels can be observed in brain dead patients, that might contribute to haemodynamic disturbances in these patients. Plasma catecholamines (epinephrine and norepinephrine) were measured by HPLC combined with electrochemical detection in 18 consecutive brain dead patients referred to the multiorgan donors unit at the Bordeaux University Hospital. Two samples were obtained: the first one at the time of donor referral (11.2 +/- 9 h after the clinical onset of brain death), and the second one just before organ procurement (19.8 +/- 1 h after the clinical onset of brain death). The results showed that plasma catecholamines levels were similar in both samples, with mean values within the normal range. There was no correlation between the plasma levels of each of the catecholamines and the mean arterial pressures at the time of sampling. Very high plasma catecholamines levels have been found by other authors after brain injuries. After the onset of brain death, they return to basal rest values and do not continue to fall as is the case in animal experiments. The haemodynamic disturbances observed in brain dead patients therefore cannot be due only to sympathoadrenal failure.

Adult↗
PubMed1991

[Elevation of atrial natriuretic factor in alveolo-interstitial lesions of connective tissue diseases].

Plasma levels of the atrial natriuretic factor were prospectively measured in 15 patients suffering from connective tissue disease with alveolar-interstitial lung lesions. The mean level was significantly higher in these patients than in 12 patients without known lung lesions (74.8 +/- 20.7 pg/ml versus 30.8 +/- 12 pg/ml; P less than 0.01) and in 18 healthy subjects (25.4 +/- 12.6 pg/ml). There was no correlation between these levels and lung function tests. Three patients with isolated lymphocytosis in the alveolar lavage fluid had a high level of atrial natriuretic factor.

Atrial Natriuretic Factor↗
PubMed1991

Low molecular weight hydroxyethyl starch 6% compared to albumin 4% during intentional hemodilution.

Intentional normovolemic hemodilution was chosen as the model to compare a 6% low molecular weight hydroxyethyl starch (LMW HES) to 4% albumin. The study ran over the plasma exchange period for 24 h. Nine patients, scheduled for abdominal aortic surgery, were included in each group. After basal measurements, blood was withdrawn and simultaneously replaced by either 4% albumin (Group 1) or 6% LMW HES (Group 2) to achieve a final hematocrit of approximately 30%. Hemodynamic blood oxygen gas and hormonal plasma levels were determined before hemodilution then at 30 min, 1, 2, 3, and 24 h after the end of hemodilution. Basal value for total blood volume was 4377 +/- 162 ml in group 1 and 4138 +/- 315 ml in group 2. As in both groups the decrease in blood cell volume was exactly compensated by the increase in plasma volume, no significant change in total blood volume (respectively 4432 +/- 159 and 4305 +/- 267 ml) was observed. Throughout the study, in both groups, no significant change in mean arterial and right atrial pressures was observed. In group 2 (LMW HES), a significant increase of pulmonary capillary wedge pressure was noted 120 min after hemodilution. After hemodilution, despite a significant decrease in arterial oxygen O2 content, systemic oxygen transport did not significantly vary until 24 h in relation to the increased cardiac index. An increase in O2 extraction was observed after the exchange but no further increase was observed until the 24 h. No significant changes either in global O2 consumption or in lactate concentration were detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Atrial natriuretic peptide level and intracardiac pressure in cardiac transplant recipients.

Blood pressures and plasma atrial natriuretic peptide (ANP) concentrations have been measured in venous and intracardiac sites in 11 patients (10 men and 1 woman) given cardiac transplants. The mean plasma ANP level was 214.4 pg.ml-1 in the superior vena cava and 281 pg.ml-1 in the right atrium. This significantly higher level was maintained in the right ventricle (269) and in the pulmonary artery (295). The level in controls was 25 pg.ml-1. Intra cardiac and mean arterial pressures were in normal range in all patients, and there was no correlation between plasma ANP level and intracardiac pressure. The data suggest that in cardiac transplant patients right atrial pressure does not have a primary role in releasing ANP. The transplanted heart is denervated and remains so for many months after operation, thus suggesting that innervation is not obligatory for ANP secretion. Further studies are required to determine the relative contribution of donor and recipient atrial tissues to ANP secretion.

Atrial Natriuretic Factor↗
PubMed1990

Beta-adrenoceptor blockade potentiates exercise-induced release of atrial natriuretic peptide.

The effect of a non selective and a cardio-selective beta-blocker on basal and exercise-stimulated plasma atrial natriuretic peptide concentrations in healthy volunteers has been studied. Nine healthy volunteers received single oral doses of 5 mg tertatolol, 100 mg atenolol or placebo, at one week intervals, in a double blind cross over trial. At rest plasma atrial natriuretic peptide, aldosterone, antidiuretic hormone and cyclic GMP concentrations and plasma renin activity were not modified by the treatments. During exercise plasma atrial natriuretic peptide concentrations were significantly increased by each treatment, the increment being significantly greater on beta-blockers than on placebo. The rise in atrial natriuretic peptide was 72% after placebo (from 24 to 42 pg/ml), 184% after atenolol (from 30 to 86 pg/ml), and 183% after tertatolol (from 34 to 95 pg/ml), respectively. Thus, the study has shown that in healthy subjects the plasma natriuretic peptide concentration is increased by exercise and that the increase is considerably and equally potentiated by selective and non selective beta-adrenoceptor blockade. The effect may be mainly due to a reduction in ventricular contractility with an increase in atrial pressure. The beta-blockers did not influence the resting plasma atrial natriuretic peptide levels, which suggests that in healthy subjects basal atrial natriuretic peptide secretion is not controlled via beta-receptors.

Adrenergic beta-Antagonists↗
PubMed1990

Cicletanine does not affect plasma atrial natriuretic peptide concentration in healthy subjects.

The effect of 50 and 150 mg cicletanine, a new vasodilator antihypertensive, on plasma atrial natriuretic peptide (ANP), cyclic GMP and antidiuretic hormone has been investigated at rest and during standardized exercise, in a double blind cross over study in healthy subjects. Exercise significantly increased in plasma ANP, cyclic GMP and antidiuretic hormone concentrations, and cicletanine did not affect any of them either at rest or during exercise. Since the alpha-1 adrenoceptor blocker prazosine decreases, beta-adrenoceptor blockers increase and the vasodilator cicletanine does not alter the plasma ANP response to exercise, it is suggested that adrenergic receptors may be directly involved in the regulation of ANP secretion.

Administration, Oral↗
PubMed1990

Thyroid function in brain-dead donors.

Twenty brain-dead potential organ donors were studied prospectively to establish thyroid function. Two or three consecutive blood samples were obtained during brain death. Seven times a sample was available before brain death occurred. Free triiodothyronine (FT3) fell in most patients (80%). Very low (less than 1.6 pmol/l) and subnormal levels (between 2 and 3 pmol/l) were found in 65% and 15% of the patients, respectively. Serum reverse total triiodothyronine (rT3) was inversely correlated with FT3. Free thyroxine (FT4) was less often decreased (mean 14.68 +/- 1.42 pmol/l) and 35% of the patients had normal levels. Mean thyroid stimulating hormone (TSH) remained normal (0.71 +/- 0.15 microU/ml). The study of consecutive samples during brain death did not show a constant, progressive decrease in hormonal levels. There is no statistical difference between values observed before and after brain death. No correlation was found between FT3 levels and hemodynamic data or immediate allograft function. The pattern of thyroid function in these patients was typical of the sick euthyroid syndrome with a low T3 or low T3 and low T4 serum levels. This syndrome usually does not need to be treated. However, many experiment findings and some clinical data argue in favor of T3 therapy in donors and possibly in recipients. The dosage regimen must be adjusted to be effective without causing harm to multiorgan donors before it can be widely used. It remains to be proved that low FT3 serum indicates low intracellular FT3 and worse metabolic function in clinical conditions.

Adolescent↗
PubMed1990

Atrial natriuretic factor in patients with acromegaly.

In acromegaly the plasma volume is chronically elevated and it returns to normal when the disease is successfully treated. To define the role of ANF in such a chronic disorder of extracellular fluid volume homeostasis the plasma level was assayed in 37 acromegalic patients with active or inactive (successfully treated) disease. Five patients were studied before and after therapy. The effects of acute change in sodium-fluid status on plasma ANF levels was examined in 7 active and 4 inactive acromegalic patients and in 7 healthy subjects. As compared to 14 patients with inactive acromegaly, 23 patients with active acromegaly had an expanded plasma volume (n = 12; 50.1 vs 37.6 ml.kg-1 BW) and an increased blood concentration of growth hormone (n = 23; 22.5 vs 2.1 ng.ml-1). Plasma ANF concentrations in active and inactive acromegalic patients (33.2 and 26.6 pg.ml-1, respectively) did not differ significantly from one another or from the level in the controls (26.9 pg.ml-1). In those patients there was no correlation between plasma volume and ANF level. Infusion of 21 isotonic saline in 2 h led to a similar, significant increase in ANF levels in active (from 26.2 to 72.4 pg.ml-1) and in inactive acromegalic patients (from 33.6 to 96.7 pg.ml-1) as well as in healthy subjects (from 21 to 70.6 pg.ml-1). Successful treatment reduced the plasma volume (from 49.2 to 35.8 ml.kg-1 BW) and growth hormone level (from 10.1 to 2.6 pg.ml-1), while the ANF level remained unchanged (from 33.8 to 35.5 pg.ml-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly↗
PubMed1990

[Hemodynamic, coagulation and glycoregulation changes induced by brain death].

Brain death results in various changes in circulation haemostasis, acid-base balance and glycoregulation. This study was carried out between February 1988 and December 1988 in 91 patients with brain death. Age range was between 6 and 58 years. The cause of brain death was brain trauma (71%) and vascular malformations (26%). In all patients a cardio-vascular collapse occurred at the moment of brain death, requiring an intravascular loading (466.3 +/- 240.3 ml.h-1) with crystalloids and albumin. Dopamine was used in 70% of cases at the dose of 3 micrograms.kg.min-1 to improve kidney and splanchnic perfusion. No alterations of acid-base balance were observed in these patients who admitted for organ donation in a short delay (17.1 +/- 6 h). Haemostasis was modified in all patients but the alterations occurred before the brain death and were related to brain injury. Further investigations are required for a better understanding of glycoregulation changes as they could influence pancreatic transplant survival. Hormonal changes have also to be more extensively studied for possible physiopathologic causes of the variations. A better understanding of these alterations will be of benefit for management of patients in brain death and potential organ donors.

Adolescent↗
PubMed1990

Renal and hemodialysis clearances of endogenous natriuretic peptide. A clinical and experimental study.

The purpose of the present study was to assess the plasma levels of atrial natriuretic peptide (ANP) in chronically uremic patients not submitted to dialysis and to determine the predialysis plasma concentration of ANP, the effect of ultrafiltration on plasma levels of ANP (hemodialysis, (HD), and the HD clearance of ANP in a population of adult patients treated with maintenance HD. The mean plasma ANP concentration (pg/ml) in HD was 370.2 +/- 35.5 pg/ml (mean +/- SEM) before HD and decreased to 165.3 +/- 15.2 after HD (p less than 0.01). Both values were significantly higher than in controls (28 +/- 2; n = 39). The changes in plasma ANP levels correlated inversely with those in plasma protein concentration (r = -0.53; p less than 0.03; y = 48.6 +/- 0.8 x). ANP clearance across the cuprophan membrane averaged 13 +/- 6.4 ml/mn. Resting plasma ANP values in the 16 uremic patients ranged between 16 and 277 pg/ml (124 +/- 11 pg/ml). These levels were significantly higher than those observed in controls (p less than 0.01). In these patients there was a highly significant correlation between serum creatinine and plasma ANP concentrations (p less than 0.01; r = 0.75; y = 0.2x + 3). Furthermore we report the results of the determination of the renal clearance of ANP in normal dogs. In all dogs a fall in plasma ANP concentration was recorded between the aorta (28.6 +/- 4.5 pg/ml) and the renal vein (14.2 +/- 2.7 pg/ml). The renal extraction ratio averaged 51.3 +/- 3.7%. Mean ANP renal clearance was 38.2 +/- 5.2 ml/mn.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Characteristics of atrial natriuretic hormone receptors in human pheochromocytomas.

The presence of functional receptors for human atrial natriuretic hormone in human pheochromocytomas was recently reported. The present study reports the binding of hANH as measured by Scatchard analysis in 4 human adrenal glands and in 5 human pheochromocytomas. Binding assays using [3H]ANH revealed a single class of high-affinity binding sites for hANH in both tissues. Human pheochromocytomas present a lower number of binding sites than normal human adrenal gland (Bmax of 7.1 +/- 2.1 vs 33.6 +/- 6.9 fmol/mg protein, respectively). However, the decreased number of ANH receptors was not paralleled by modifications of tissular cyclic GMP (cGMP). Moreover, plasma hANH concentrations in 7 patients with pheochromocytomas (20.2 +/- 2.7 pmol/l) were statistically higher than those obtained in 25 normal control humans (8.1 +/- 0.6 pmol/l, p less than 0.001). We also demonstrated the presence of immunoreactive ANH in the tumour itself.

Adrenal Gland Neoplasms↗