PubMed Health⌕ Search

Biomedical subjects

E Comoy

Publications and source records attributed to E Comoy.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Familial pheochromocytoma and Van Hippel-Lindau disease].

The authors report the case of a 41-year old man who presented simultaneously with phaeochromocytoma, paraganglioma and renal carcinoma. The postoperative finding of metaiodobenzylguanidine uptake foci showed that the phaeochromocytoma was malignant. The patient's son had a phaeochromocytoma and a pancreatic cyst. The phaeochromocytoma had no clinical manifestations and had been discovered by systematic assays of urinary catecholamines and their derivatives. These abnormalities are those of Von Hippel-Lindau disease.

Adolescent↗
PubMed1990

Changes in hypothalamic neuropeptide Y concentrations induced by cholecystokinin analogues.

Neuropeptide Y (NPY) and cholecystokinin (CCK) are two peptides involved in opposite ways in the control of food intake. A possible interaction between NPY and CCK has not yet been well defined. Two CCK derivatives with agonistic and antagonistic properties were studied with regard to their effects on brain and plasma NPY levels. The CCK agonist decreased NPY levels in plasma and in the hypothalamus but not in the other brain areas assayed. The CCK antagonist reversed the agonist-induced decrease in both plasma and hypothalamus. These results suggest a negative relation between NPY and CCK peptides, which is not surprising given their opposite role in feeding regulation. The hypothalamus, a preferential site of this regulation, appears to be the brain area most involved in the NPY-CCK interaction. The plasma NPY level variations closely reflect the hypothalamic profile, suggesting a direct release of NPY by a mechanism that remains to be investigated.

Animals↗
PubMed1990

Changes in brain neuropeptide Y induced by cholecystokinin peptides.

Cholecystokinin (CCK) and neuropeptide Y (NPY) are two peptides with opposite effects on the regulation of feeding behaviour. The possible interaction between these two systems has always been controversial. In this study, rat brain NPY levels were assayed after treatment with CCK 8 S and with a potent CCK agonist (Boc-(Nle 28-Nle 31)-CCK 26-33). CCK 8 S and its agonist analogue (50 micrograms/kg i.p.) both decreased hypothalamic and hippocampal NPY levels. This result suggests a negative relationship between NPY and CCK-peptides which is not surprising given their opposite role in the control of feeding. The hypothalamus and secondarily the hippocampus appear to be the site of this interaction; no change in NPY levels was observed in other brain areas (striatum and cortex). The same pattern of variation was found in the plasma, suggesting a direct release from the brain via a mechanism which remains to be investigated. The effect appeared later with the CCK analogue than with CCK 8 S itself; this is not surprising with regard to other behavioural and biochemical effects of the analogue and provides further characterization of its action.

Animals↗
PubMed1990

Stability of epinephrine in alkalinized solutions.

STUDY OBJECTIVE: Increasing the pH of an epinephrine solution favors its oxidation and may result in a decrease in its biological activity. It is therefore generally assumed that epinephrine and sodium bicarbonate should not be infused in the same IV line during CPR. The aim of this study was to determine the validity of this widely accepted proposition. DESIGN AND SETTING: Two different commercial solutions of epinephrine differing only in the concentration of sodium metabisulfite (0.46% and 0.02%) were studied. Two dosages of each solution type (1 mg/1 mL and 10 mg/10 mL) were diluted in 250 mL of 8.4% sodium bicarbonate. MEASUREMENTS AND MAIN RESULTS: The concentration of epinephrine was measured at different times for two weeks. It was found that the concentration of epinephrine decreased slowly to zero after two weeks, and was approximately at 70% and 100% of control values at 30 minutes after alkalinization. CONCLUSION: It was concluded that epinephrine in an alkaline solution is effectively oxidized but has a slow reaction that may not be clinically relevant over short periods of time.

Bicarbonates↗
PubMed1989

Plasma neuropeptide Y concentrations in patients with neuroendocrine tumors.

In order to develop an immunoradiometric assay for human neuropeptide (hNPY), a recently discovered and potent vasoconstrictor 36-amino-acid peptide, we used hNPY and some of its subpeptides to prepare monoclonal anti-NPY antibodies. Two monoclonal antibodies with high affinity for hNPY, that is affinity constants in the range of 10(10) mol/L-1, which respectively, reacted with the 9-18 portion and the 32-36 portion of hNPY were used in the immunoradiometric system. The assay was highly specific, NPY-related peptides such as pancreatic polypeptide and peptide YY not being detected. The lower limit of sensitivity was 0.5 pmol/L. In 303 normal subjects, plasma NPY concentrations were less than 0.5 pmol/L in 67%, 0.5 to 5.0 pmol/L in 25% and 5.1 to 30 pmol/L in the remaining 8%. A value of 7.5 pmol/L (95th percentile value in the normal group) was considered as the upper limit of normal. Among 111 patients with various neuroendocrine tumors, elevated plasma NPY concentrations were found in patients with pheochromocytomas and neuroblastomas, the highest plasma levels being found in patients with malignant pheochromocytomas. We conclude that patients with neuroendocrine tumors, especially secreting and or malignant tumors of the sympathochromaffin system, often have elevated plasma NPY concentrations.

Adolescent↗
PubMed1989

[Blood amylase: a biological marker in irradiation accidents? Preliminary results obtained at the Gustave-Roussy Institut (GRI) and a literature review].

The retrospective evaluation of the dose after an irradiation accident is of paramount importance; it allows an adequate selection of patients and the most appropriate treatment can then be proposed. Classical physical dosimetry often lacks precision for dose assessment in such accidents. Cytogenetics, usually more reliable, is not 100% accurate and cannot be used in some particular instances. At the Institut Gustave-Roussy, we studied amylasemia in 15 patients who received a total body irradiation (TBI) for bone marrow grafting, at various dose levels (10, 2 and 1.35 Gy). Hyperamylasemia was found to be constant and dose-dependent. Ten additional patients given a localized irradiation of 2 Gy in the Waldeyer ring had a similar rise in amylasemia as did TBI patients who had received the same dose. In contrast, 13 patients given a pancreatic irradiation (as part of a localized abdominal irradiation) did not show any increase in amylasemia. This study seems to confirm reported data, which suggested that post-TBI hyperamylasemia is almost only related to salivary gland irradiation. Amylasemia could possibly be used as a "biological dosimeter"; however, the dose-effect relationship should be more precisely defined, as well as individual variations. Moreover, the definition of a "threshold-dose" below which hyperamylasemia can never be detected, would be of interest for radioprotection.

Amylases↗
PubMed1988

Plasma renin activity in phaeochromocytoma: effects of beta-blockade and converting enzyme inhibition.

We measured plasma renin activity and plasma catecholamines in 26 untreated patients with phaeochromocytoma, 18 untreated patients with primary hypertension, and 10 normal control volunteers. Plasma renin activity measured in patients in the supine position, standing position and after walking for 1 h was higher in the subjects with phaeochromocytoma than in those with primary hypertension or in the volunteers (F = 9, P less than 0.001). In all three situations, renin activity was closely correlated with noradrenaline levels in the phaeochromocytoma patients (r = 0.545, r = 0.600, and r = 0.739; P less than 0.01) but not in the subjects with primary hypertension or in the volunteers. The cardioselective beta-blocker acebutolol reduced heart rate, mean blood pressure and renin activity by averages of 20, 12 and 89% respectively in the seven phaeochromocytoma patients given the drug. Captopril decreased mean blood pressure by 19% and raised renin activity by 293% in the nine phaeochromocytoma patients tested. These findings show that in phaeochromocytoma, hypertension is accompanied by high renin levels and that renin release is stimulated in response to noradrenaline overflow. The hypotension observed in response to beta-blockade and captopril provides indirect support for the possibility that renin-dependent mechanisms are involved in the hypertension of phaeochromocytoma.

Acebutolol↗
PubMed1988

Mild isocapnic hypoxia enhances the bronchial response to methacholine in asthmatic subjects.

We studied the effect of mild isocapnic hypoxia (FIO2 = 15.5%) on lung mechanics, heart rate, circulating plasma catecholamines, and bronchial responsiveness to methacholine in ten asthmatic adults. Hypoxia did not alter lung mechanics (i.e., dynamic pulmonary compliance [CLdyn], pulmonary resistance [RL]) nor did it increase plasma catecholamines, but it significantly increased bronchial responsiveness to aerosolized methacholine, as assessed by the fall in forced expiratory volume in one second (FEV1: 1.2 +/- 0.18 versus 0.9 +/- 0.14 L/s, p less than 0.05), the rise in RL (RL: 19.1 +/- 1.4 versus 8.4 +/- 1 cm H2O/L/s, p less than 0.05), and the steeper slope of the dose-response curve to methacholine. We concluded that the hypoxic characteristic of asthmatic attacks may aggravate airflow obstruction.

Adult↗
PubMed1987

[Role of ultrasensitive TSH assay and ultrarapid total thyroxine assay in the thyroid studies].

The diagnostic value of high sensitivity thyrotrophin assay (HS-TSH) and that of ultra-short determination of total thyroxine (T4) by fluorescence polarization (T4-TDX) were evaluated in 284 patients (29 hyperthyroid, 137 euthyroid without treatment and 118 under substitutive therapy). After comparing the clinician's first impression with the results of these laboratory tests the proportion of correctly classified untreated euthyroid patients was the same with T4-TDX as with HS-TSH (90%). In contrast, this proportion in hyperthyroid patients was about twice as low with HS-TSH (23%) as with T4-TDX (42%). While HS-TSH gives a better diagnostic evaluation, T4-TDX is an excellent indicator of the degree of hyperthyroidism. In patients under suppressive therapy HS-TSH and T4-TDX provide a better evaluation of therapeutic effectiveness.

Adolescent↗
PubMed1987

[Postoperative surveillance of differentiated thyroid epithelioma. Contribution of the ultrasensitive determination of TSH].

Ultra-sensitivity TSH assays were performed, using Behring's kit (sensitivity: 0.03 microU/ml, in 183 patients operated upon for differentiated thyroid carcinoma and followed up while under treatment with L-thyroxine. Clinically, all patients were euthyroid. TSH was undetectable in 38 patients and within normal limits in 93. A negative correlation was found between the logarithm of thyroxine plasma levels and that of TSH levels, but there were many discrepancies (normal thyroxine level with undetectable TSH, high thyroxine level with normal TSH level). This study shows that the ultra-sensitive TSH assay provides accurate information on the inhibition of TSH secretion. Clinical evaluation and plasma thyroxine assays are needed to make sure that the patient is in a euthyroid state.

Adolescent↗
PubMed1987

[Measurement of platelet catecholamine content for the diagnosis of pheochromocytoma with intermittent hypertension].

We have compared platelet and plasma catecholamines (radioenzymatic assay with catechol-O-methyl transferase) and urinary metanephrines (high performance liquid chromatography) in 16 patients with phaeochromocytoma, 12 essential hypertensives, and 15 normotensive volunteers. Hypertensive patients with or without phaeochromocytoma had labile or paroxysmal hypertension with normal or borderline blood pressures between paroxysms. Catecholamine concentrations in platelets and plasma did not differ in essential hypertensives and controls, but were higher in patients with phaeochromocytoma than in subjects without tumour, with values overlapping between groups. Metanephrine excretion was markedly higher in phaeochromocytoma than in essential hypertension, with no intergroup overlap. Platelet adrenaline plus noradrenaline content was highly correlated to urinary metanephrines (r' = 0.830, n = 28 p less than 0.01). Using as a cut-off point the highest values measured in essential hypertensives, the sensitivity of each measurement was 1.00 for metanephrines, 0.87 for platelet catecholamines and 0.50 or less for plasma catecholamines. Measurement of platelet catecholamine content is a sensitive test and an appropriate alternative to metanephrine measurement in the difficult cases of suspected phaeochromocytoma with intermittent hypertension.

Adrenal Gland Neoplasms↗
PubMed1986

Delta aminolevulinic acid dehydratase amounts in lead-exposed subjects: description of a method correlated with the immunoturbidimetric assay.

The measurement of delta-aminolevulinic acid dehydratase (ALA.D) activity is a good index of lead exposure. Recently, we proposed an immunoturbidimetric assay which allows determination of the amount of the enzyme. This last test is particularly interesting for workers presenting high blood-lead levels. We then studied the effects of different agents (dithiothreitol, heat and zinc ions) in restoring the activity of lead-inhibited ALA.D. The individual or combined effects of these three agents showed an additive restoration of activity. The combination of zinc ions with heat and/or DTT gave the best activations, which correlated perfectly with ALA.D amounts. Consequently, the catalytic assay using zinc ions and DTT may be used in routine testing as an indirect measurement of ALA.D amount.

Dithiothreitol↗
PubMed1986

Dopamine-beta-hydroxylase (DBH) and homovanillic acid (HVA) in autistic children.

In the present study, plasma DBH activity and urinary HVA levels were measured in 19 autistic and 15 normal children. DBH activity was significantly elevated in the 8 less retarded autistic patients. In this subgroup, a negative correlation was found between plasma DBH and urinary HVA levels. These results support the hypothesis of a possible involvement of brain catecholamine dysfunction in the production of autistic symptoms.

Age Factors↗
PubMed1986

Alterations in isoprenaline sensitivity in patients with cirrhosis: evidence of abnormality of the sympathetic nervous activity.

Isoprenaline sensitivity and plasma catecholamine concentrations were studied to assess the sympathetic nervous activity in 13 patients with alcoholic cirrhosis and were compared with five controls. In patients with cirrhosis, the dose of isoprenaline required to increase the resting heart rate by 25 beats min-1 (chronotropic dose 25 or CD25) ranged from 2.50 to 34.73 micrograms (median: 4.47 micrograms) and was significantly higher than in controls (range: 0.66 to 2.76 micrograms, median: 1.34 micrograms). In cirrhotic patients, CD25 values were significantly correlated with plasma albumin concentration, resting heart rate and wedged hepatic venous pressure. In patients with cirrhosis, plasma noradrenaline concentrations ranged from 192 to 978 pg ml-1 (median: 444 pg ml-1) and adrenaline concentrations ranged from 5 to 183 pg ml-1 (median: 47 pg ml-1). No correlation was found between noradrenaline or adrenaline concentrations and CD25 values in cirrhotic patients. In conclusion, in patients with cirrhosis, beta-adrenoceptor responsiveness assessed by isoprenaline sensitivity is altered.

Adult↗
PubMed1985

Effects of nifedipine on responses to exercise in normal subjects.

The responses to sublingual nifedipine (20 mg) and placebo were compared in normal subjects during two studies on cycle ergometer [progressive exercise and constant work-load exercise at approximately 60% of maximal O2 consumption (VO2max)]. The use of nifedipine did not modify maximal power, ventilation (VE), VO2, and heart rate (HR) at the end of the multistage progressive exercise (30-W increments every 3 min). Over the 45 min of the constant-load exercise and the ensuing 30-min recovery we observed with nifedipine compared with placebo 1) no differences in VO2, VE, respiratory exchange ratio, and systolic arterial blood pressure; 2) a higher HR (P less than 0.001) and lower diastolic arterial blood pressure (P less than 0.01); 3) a greater and more prolonged rise in norepinephrine (P less than 0.01) and growth hormone (P less than 0.001); 4) no significant differences in epinephrine and insulin and a lesser increase in glucagon during recovery (P less than 0.01); and 5) a lesser fall in blood glucose (P less than 0.01) and greater increase in acetoacetate (P less than 0.001), beta-hydroxybutyrate (P less than 0.05), and blood lactate (P less than 0.001). Our data do not support the hypothesis that nifedipine reduces hormonal secretions in vivo and are best explained by an enhanced secretion of catecholamines compensating for the primary vasodilator effect of nifedipine.

3-Hydroxybutyric Acid↗
PubMed1985

Plasma renin activity, blood uric acid and plasma volume in pregnancy-induced hypertension.

UNLABELLED: Plasma renin activity (PRA), plasma aldosterone (PA), blood uric acid (BUA), plasma concentrations of catecholamines (Pcat) and plasma volume (PV) were measured simultaneously in 24 patients with pregnancy-induced hypertension. This hypertensive group was divided into labile (LH) and permanent hypertension (PH) groups according to the response of their blood pressure to home bed rest. As compared to normal theoretical values, PV was decreased in both hypertensive groups (LH = -70%; PH = -14%). As compared to a control group of 16 normotensive pregnant women, PRA was higher in LH and lower in PH whereas PA was lower in both hypertensive groups. In both hypertensive groups, BUA was higher than in the control group. No difference in Pcat was found between the three groups. In the PH group negative correlations were found between BUA and PRA, as well as between BUA and PV, but no correlation between PRA and PV nor between Pcat and BUA were found. CONCLUSIONS: LH and PH are two pathophysiologically different entities in pregnancy-induced hypertension. In PH, renin secretion is not appropriate to hypovolemia and therefore not primarily involved in the pathogenesis of hypertension. The role of hypovolemia in the increase of BUA may be discussed.

Female↗