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Biomedical subjects

J B Corcuff

Publications and source records attributed to J B Corcuff.

At least 19 recordsLinked to original sources
PubMed2001

Progressive enhancement of delayed hyperalgesia induced by repeated heroin administration: a sensitization process.

It is difficult to conceive that tolerance and sensitization processes, two apparently opposite phenomena, can concomitantly modify one given biological process, i.e., the processing of pain. We have shown recently that opiates produce not only analgesia but also long-lasting hyperalgesia in rats. This suggests that tolerance to the analgesic effect of an opiate, especially heroin, could be in part the result of an actual sensitization of pronociceptive systems. Here, we show that both magnitude and duration of heroin-induced delayed hyperalgesia increase with intermittent heroin administrations, leading to an apparent decrease in the analgesic effectiveness of a given heroin dose. Our observation that a small dose of heroin which is ineffective for triggering a delayed hyperalgesia in non-heroin-treated rats induced an enhancement in pain sensitivity for several days after a series of heroin administrations is in agreement with the sensitization hypothesis. The effectiveness of the opioid receptor antagonist naloxone to precipitate hyperalgesia in rats that had recovered their pre-drug nociceptive value after single or repeated heroin administrations indicates that heroin-deprived rats were in a new biological state associated with a high level balance between opioid-dependent analgesic systems and pronociceptive systems. Because the NMDA receptor antagonist dizocilpine maleate (MK-801) prevented both heroin-induced long-lasting enhancement in pain sensitivity and naloxone-precipitated hyperalgesia, these findings further suggest that tolerance, sensitization, and one withdrawal symptom, hyperalgesia, are issued from a neuroadaptive process in which NMDA systems play a critical role.

Animals↗
PubMed2001

Assessment of brain natriuretic peptide in patients with suspected heart failure: comparison with radionuclide ventriculography data.

BACKGROUND: The aim of the study was to prospectively evaluate patients with suspected or known heart disease using plasma brain natriuretic peptide (BNP) measurement and radionuclide ventriculography to examine whether left ventricular dysfunction is associated with an abnormal rise of BNP concentration. METHODS: Patients (n=153) and controls (n=14) underwent radionuclide ventriculography to determine Left ventricular Ejection Fraction (LVEF) and measurement of plasma BNP concentration using a commercial kit. RESULTS: Plasma BNP concentration in controls was significantly lower than that in patients whatever the stage of the disease, significantly lower than that of patients with normal LVEF (LVEF>55%); than that of patients with altered LVEF (LVEF< or =40%); and than that of patients with moderately reduced LVEF (40%<LVEF< or =5%). Comparisons between groups of patients showed that the more severe the disease, the higher the BNP level. From the ROC curve, a plasma BNP concentration of 52 pg/ml was attached to a 85% sensitivity and 82% specificity in identifying patients with LVEF< or =40%. CONCLUSIONS: Plasma BNP concentration provides a reliable and sensitive marker of LV systolic dysfunction evaluated by a nuclear medicine technique, and could be a potential screening test to identify patients for additional investigations.

Cardiac Output, Low↗
PubMed2001

Lessons from an unpleasant surprise: a biochemical strategy for the diagnosis of pheochromocytoma.

OBJECTIVE: To audit the performances of the analytes used in the diagnosis of pheochromocytoma and to present a graphical guideline to help the diagnosis. DESIGN: A 5 year retrospective study. SETTINGS: Laboratory and departments of a university hospital. PARTICIPANTS: In-patients, suspected of bearing a pheochromocytoma, were investigated for urinary metanephrines and catecholamines (photometric method) and vanillylmandelic acid, fractionated catecholamines and metanephrines [high pressure liquid chromatography (HPLC) coupled to electrochemical detection (ED)] urinary excretion. MAIN OUTCOME: Patients with a pheochromocytoma (24 out of 2003 patients) were diagnosed by the combination of normetanephrine and metanephrine determination. RESULTS: All analytes but dopamine were significantly elevated in patients with a pheochromocytoma. The area under the receiver operating characteristics (ROC) curves were the highest for total metanephrines, normetanephrine and metanephrine determinations. Because of analytical interferences in the metanephrines determination, the normetanephrine and metanephrine performed better. It is noteworthy that all pheochromocytomas had either normetanephrine or metanephrine levels above their respective optimal threshold (sensitivity 100%). The best optimal threshold performance was reached by the mean of three daily samples. Total or fractionated catecholamines or vanillylmandelic acid were less accurate tools. CONCLUSION: Amongst urinary tests, the combined use of HPLC/ED determination of normetanephrine and metanephrine seems the most effective screening strategy for the diagnosis of pheochromocytoma. The older total metanephrine photometric assay is grieved by analytical interferences.

Adolescent↗
PubMed2001

Decreased pituitary sensitivity to glucocorticoids in endurance-trained men.

OBJECTIVE: Muscular exercise induces hypothalamo-pituitary-adrenal (HPA) axis activation and when regularly repeated, as in endurance training, leads to HPA axis adaptation. To assess whether non-professional endurance-trained (ET) men with a substantial training load and no clinical or biological features of HPA axis overactivity can present subtle alterations of HPA axis sensitivity to glucocorticoid negative feedback, nine ET men were subjected to HPA axis testing using the dexamethasone-corticotrophin-releasing hormone (CRH) test. DESIGN: Nine endurance-trained men and eight healthy age-matched sedentary men were studied. Morning plasma cortisol and 24 h urinary free cortisol (UFC) were determined and a low dose dexamethasone suppression test (LDDST) was performed followed by CRH stimulation (dexamethasone-CRH test). RESULTS: After a day without physical exercise, at 0800 h, plasma ACTH and cortisol concentrations, and the 24 h UFC and UFC/urinary creatinine (UC) ratio were similar in ET and sedentary men. By contrast, clear differences between the groups were seen in cortisol and ACTH responses to the dexamethasone-CRH test. In eight ET subjects, after LDDST, basal ACTH and cortisol levels were similar to those of sedentary men, whereas one ET subject displayed a poor suppression of cortisol level (131 nmol/l). After injection of CRH, however, three of nine ET men's cortisol levels were not suppressed by dexamethasone but instead displayed significant CRH-induced increase (peak cortisol: 88, 125 and 362 nmol/l). No sedentary subject exhibited any increase in cortisol levels. CONCLUSION: Three of nine ET men with a mean maximum rate of O2 uptake (VO2, max) of 61 ml/kg per min, running 50-70 km per week, were resistant to glucocorticoid suppression during the combined dexamethasone-CRH test.

Adult↗
PubMed1999

Abdominal obesity increases overnight cortisol excretion.

Although plasma and 24 h urinary free cortisol (UFC) levels are normal in obese subjects, pharmacological investigations have identified minor hypothalamo-pituitary-adrenal axis differences in patients with abdominal body fat distribution (A-BFD) vs peripheral BFD (P-BFD). Using recent tools such as saliva cortisol or overnight urinary free cortisol upon creatinine ratio (UFC/UC) determinations, we have investigated a population of obese females according to their body fat distribution. In-patients subjects (no.=82) were subjected to routine biochemical testing, 24 h and overnight UFC/UC, basal and post-1 mg overnight dexamethasone-suppressing test plasma and saliva cortisol determinations. Central obesity defined by a waist-to-hip ratio (WHR) >0.85 was found in 64% of the subjects vs 87% when defined by waist girth (WG) corrected for age. Despite identical body mass index, A-BFD subjects were more prone to hypertension using both classifications and had higher triglycerides (WHR classification) or higher triglycerides, cholesterol and glycemia (WG classification). Plasma cortisol levels were similar but saliva cortisol levels were lower in the A-BFD group using the WG classification. The 24 h UFC/UC were similar but the overnight UFC/UC were higher in the A-BFD group using the WHR classification. These mild differences in cortisol nocturnal secretion and free cortisol indexes in subjects with different body fat mass distribution suggest that their hypothalamo-pituitary-adrenal axis has a spontaneously subtly different regulation.

Abdomen↗
PubMed1999

Rapid leptin decrease in immediate post-exercise recovery.

OBJECTIVE: Leptin concentrations in humans are known to decrease in response to fasting. The aim of this work was to investigate whether leptin levels might also be modified by exercise-induced negative energy balance. SUBJECTS: Eight male runners reported in the morning from 0800 to 1200 h for (i) one resting session (sitting) and (ii) one exercise-and-rest session (2 h run and 2 h rest). MEASUREMENTS: Plasma leptin, free fatty acids (FFA), glycerol, cortisol and salivary cortisol were assayed in both sessions at 1200 h. RESULTS: After exercise-and-rest the leptin concentrations were lower than after rest (1.7 +/- 0.1 vs 2.5 +/- 0.2 micrograms/l, P < 0.05), i.e. a mean decrease of 30.3 +/- 4.5% (range 9.5-45.8). Plasma FFA, glycerol and cortisol concentrations increased: FFA 0.78 +/- 0.08 vs 0.18 +/- 0.04 mmol/l, glycerol 0.13 +/- 0.01 vs 0.04 +/- 0.01 mmol/l, and cortisol 428 +/- 36 vs 279 +/- 27 nmol/l. A negative correlation was found between plasma FFA and leptin levels (r = -0.5, P < 0.05) and between plasma glycerol and leptin levels (r = -0.05, P < 0.05). No correlation was found between leptin and cortisol levels. CONCLUSIONS: In normal subjects with low body fat, a strenuous exercise-and-rest lowers leptin levels by a mean of 30%. A role of lipolysis possibly via increased plasma free fatty acids and glycerol levels is suggested. Cortisol does not seem to be involved.

Adult↗
PubMed1999

The dexamethasone-suppressed corticotrophin-releasing hormone stimulation test in anorexia nervosa.

OBJECTIVE: The dexamethasone-CRH test (combination of dexamethasone-induced suppression of HPA axis function and subsequent stimulation with oCRH) (Dex-CRH test) has been proposed to fully distinguish ACTH-dependent Cushing's disease (CD) from pseudo-Cushing's states (PCS), i.e. tumoural vs. functional hypercortisolism. A plasma cortisol concentration greater than 38 nmol/l 15 min after CRH injection has been demonstrated to identify all cases of CD and to exclude all cases of PCS. Although obviously not a PCS from a clinical point of view, anorexia nervosa (AN) is associated with CRH-driven hyperactivity of the HPA axis. This study reports the response of AN patients, a model of functional biological hypercortisolism, to the Dex-CRH test. PATIENTS AND METHODS: Nineteen women affected with anorexia nervosa and 6 healthy sex-matched controls were studied. RESULTS: Three of 19 AN patients had an abnormal 24-h urinary free cortisol excretion (UFC), whereas 1 of 19 AN had increased overnight UFC. AN subjects had inadequately suppressed plasma cortisol after low-dose dexamethasone suppression test (LDDST) (cortisol 192.8 +/- 63.4 vs. < 27 nmol/l, AN vs. controls, respectively). Seven of 19 AN patients had plasma cortisol levels above 50 nmol/l after LDDST. None of the AN patients had CRH-induced increases in plasma ACTH or cortisol (basal cortisol 192. 8 +/- 63.4 and peak cortisol 181.7 +/- 59.9 nmol/l). Despite unresponsivenessto CRH and because of the lack of suppression after dexamethasone, using the single plasma cortisol threshold value of 38 nmol/l obtained at 15 min during the Dex-CRH test would have been misclassified in half of our AN population (9 of 19). CONCLUSION: Since anorexia nervosa represents a model of functional hypercortisolism that shares similar pathophysiological mechanisms to the other causes of pseudo-Cushing's states, we suggest testing all causes of pseudo-Cushing's states using the dexamethasone-CRH approach to (i) describe the actual responses of clinically relevant pseudo-Cushing's states and (ii) to improve our knowledge of the pathophysiological discrepancies between the various causes of pseudo-Cushing's states. Lastly, the evaluation of dexamethasone metabolism (absorption, volume of distribution, clearance) may help to gain more insight into the diagnostic value of the dexamethasone-CRH test.

Adrenocorticotropic Hormone↗
PubMed1998

Corticotroph axis sensitivity after exercise in endurance-trained athletes.

OBJECTIVE: The present study was conducted in order to describe human hypothalamo-pituitary adrenal (HPA) axis adaptation in a model of repeated physical stress (endurance training) that causes a moderate increase in cortisol levels. SUBJECTS: We performed the same stimulation tests (adrenal stimulation with ACTH or pituitary stimulation with combined CRH/LVP) in a population of 8 endurance-trained athletes in two distinct situations: resting (baseline cortisol values) and 2 h after the end of strenuous exercise (increased cortisol values) to evaluate the HPA axis sensitivity to endogenous sustained increases in cortisol concentrations. MEASUREMENTS: During these tests, saliva and plasma cortisol (Fs and Fp, respectively) were assessed and compared. RESULT: Cortisol values in both plasma and saliva at the end of 2 h of exercise were significantly higher than in rested controls: Fs 11.5 +/- 1.3 vs 6.5 +/- 0.8 nmol.l-1 and Fp 428 +/- 36 vs 279 +/- 27 nmol.l-1 (post exercise vs post rest sessions, respectively, P < 0.001 for both). After either hormone test (CRH/LVP or ACTH), cortisol levels in plasma and saliva increased similarly when rest was compared to post exercise. Saliva variations (delta %) under exogenous hormone stimulation were dramatically greater than plasma variations. For example, under ACTH stimulation, the relative increments in cortisol were on control day: delta Fs 980 +/- 139 vs delta Fp 218 +/- 43% (saliva vs plasma, respectively, P < 0.05) and on exercise day: delta Fs 605 +/- 89 vs delta Fp 102 +/- 14% (saliva vs plasma, respectively, P < 0.05). CONCLUSIONS: In endurance-trained athletes, displaying a moderate but sustained endogenous cortisol increase: (1) ACTH responses following pituitary stimulation are not blunted, (2) cortisol responses following maximal adrenal stimulation are not blunted. Our results favour the hypothesis of a decreased pituitary sensitivity to cortisol negative feedback whereas the hypothesis of a major decreased adrenal sensitivity to ACTH was discarded. The greater ability of saliva assays to detect a cortisol increase strongly supports its use in the study of HPA physiology, whether under basal or dynamic conditions.

Adrenocorticotropic Hormone↗
PubMed1998

Overnight urinary free cortisol determination: a screening test for the diagnosis of Cushing's syndrome.

OBJECTIVE: The collection of urine over 24 h to measure free cortisol (UFC) is used to diagnose Cushing's syndrome. However, a complete collection of urine is not easy to achieve and the sampling is frequently inaccurate, so a 24 h collection for the determination of UFC excretion is used as a confirmatory rather than a screening test for Cushing's syndrome. Our objective was to evaluate a more convenient urine collection for screening patients suspected of Cushing's syndrome. DESIGN: We have studied the possibility of using night-time (from 2000 h to 0800 h) UFC excretion as a screening test for Cushing's syndrome ('overnight UFC'). PATIENTS: Thirty patients with proven Cushing's syndrome were studied before treatment (21 cases of Cushing's disease, two cases of ectopic ACTH secretion, seven of adrenal adenoma). The results were compared to those from 150 control obese subjects. MEASUREMENTS: Overnight UFC, and creatininuria (UC), were evaluated at least once in the patients and in all subjects. The 24 h-UFC and UC were determined at least once in the patients and in 56 control subjects. RESULTS: The overnight UFC/UC ratio clearly separated all but one patient of the two groups: 194 +/- 386 vs 5.7 +/- 3.4 nmol/mumol (P < 0.0005) (ranges 16.2-2024 vs 0.6-17.4, Cushing's syndrome vs controls, respectively). The only patient with Cushing's syndrome who had an overnight UFC/UC ratio that overlapped with that of controls suffered from renal failure. The 24 h UFC/UC ratio of the patients differed from the ratio of controls: 184 +/- 365 vs 8.4 +/- 4.1 nmol/mumol (P < 0.0005) (ranges 14-1639 vs 1.5-21.2, respectively). Four patients with Cushing's syndrome had 24 h UFC/UC ratios lower than the upper control ratio. CONCLUSION: The overnight urinary sampling is a simple procedure compared to the 24 h urine collection performed in out-patients. For a sensitivity set at 100%, the specificities were 97% for the overnight UFC/UC ratio and 87% for the 24 h-UFC/UC ratio. This therefore appears to provide a good screening method for Cushing's syndrome.

Adult↗
PubMed1997

Isolated corticotroph insufficiency associated to myasthenia gravis.

Myasthenia gravis, a neuromuscular junction autoimmune disease, may be associated to glandular autoimmune diseases such as adrenalitis. We report here the association of myasthenia gravis with a rare cause of adrenocortical deficiency, i.e. isolated corticotroph deficiency. The patient suffered from myasthenia gravis for 5 yr when she reported increased asthenia. Basal cortisol and ACTH levels were low. Metyrapone failed to increase ACTH and 11-desoxycortisol. Corticotropin-releasing hormone or tetracosactide failed to increase normally the cortisol levels. No other endocrine dysfunction or autoimmune disease could be detected. This observation enlarges the spectrum of endocrine diseases associated to myasthenia gravis and strengthens the need for careful endocrine examination.

Adrenocorticotropic Hormone↗
PubMed1997

Trained versus untrained men: different immediate post-exercise responses of pituitary adrenal axis. A preliminary study.

The hypothalamo-pituitary-adrenal axis is involved throughout the exercise-recovery cycle. Nevertheless, differences in hormone responses during early recovery between sedentary and endurance trained subjects are not well known. The aim of this preliminary study was to monitor plasma cortisol and adrenocorticotropic hormone (ACTH) concentrations both during and after the end of running exercise performed by four endurance trained adults (marathon men) compared to four sedentary subjects. Two parameters, i.e. intensity and duration, were changed on 4 consecutive days. The 1st day (D0) was spent in the laboratory: all blood samples were obtained at rest to determine diurnal variations of each hormone. On the following days (D1-D4) the subjects exercised: D1 and D2 brief (20 min), light (50% maximal heart rate HRmax, D1) or strenuous (80% HRmax, D2), D3 and D4 prolonged (120 min), light (D3) or strenuous (D4). In both groups, neither brief (D1, D2) nor prolonged light exercise (D3) induced any significant variation in plasma ACTH or cortisol concentrations. Plasma ACTH and cortisol concentrations increased only if the exercise was intense and prolonged (D4). The training factor did not modify the intensity or duration thresholds for the activation of the pituitary-adrenocortical response to exercise in the conditions of our experiment. However, during immediate recovery from the four exercise regimens, the plasma ACTH concentrations of the marathon men were constantly above the values of the sedentary subjects, although plasma cortisol concentration remained similar in both groups. As an indirect means of evaluating the relationships between ACTH and cortisol we compared the areas under the cortisol and ACTH curves (AUC) from 0.5 to 3.5 h during recovery from D1 to D4 compared to D0 at the same time. Cortisol AUC were similar in the sedentary subjects and marathon men although the ACTH AUC were different in the sedentary subjects and marathon men, suggesting a change in the pituitary-adrenal relationship at some yet indeterminate level. During the immediate recovery from exercise whatever its intensity, the magnitude of the ACTH response was increased in the trained subjects but with a reduced effect upon its target, the adrenal glands. This phenomenon has not been described in the literature. Two non-exclusive phenomena may be involved, i.e. a decreased adrenal sensitivity to ACTH stimulation, and/or a decreased hypothalamo-pituitary axis sensitivity to cortisol negative feedback.

Adrenal Glands↗
PubMed1997

Ocular naevus and melanoma in acromegaly.

Acromegaly favours the development of extrapituitary neoplasms presumably promoted through increased GH and IGF-I levels. We describe here two patients which acromegaly and benign and malignant melanocytic tumours of the eye choroid. The first patient had a 15 year history of progressive acromegaly despite trans-sphenoidal surgery, radiation and bromocriptine therapy when she presented with melanoma of the eye and a contralateral benign melanocytic tumour. The second patient was referred with typical acromegaly. The initial fundal examination revealed a right sided benign melanocytic tumour of the choroid. Subsequent follow up of the naevi has not shown any change in the tumours after one and three years respectively. The occurrence of melanoma has not been reported in acromegaly. Increased growth of benign naevi might be expected as GH and IGF-I receptors have been described on melanocytes. As naevi may degenerate into melanomas in normal subjects and radiation therapy could trigger their transformation, we suggest that prior to irradiation, acromegalic subjects should undergo a careful ocular examination in order to assess the presence of ocular naevi.

Acromegaly↗
PubMed1997

Multiple endocrine neoplasia type 2: management of patients and subjects at risk. French Study Group on Calcitonin-Secreting Tumors (GETC).

Multiple endocrine neoplasia type 2 (MEN-2) is an inherited multiglandular disease with age-related penetrance and variable expression. The prognosis of MEN-2 is linked to the carcinological evolution of medullary thyroid cancer (MTC), which depends mainly on the stage of discovery, and to the incidents related to pheochromocytomas. The emphasizes the need for early diagnosis and management of MEN-2. Since 1993, mutations evidenced on the protooncogene RET have allowed subjects at risk to be identified, thus leading to a three-step management of these patients. (1) For all the potentially affected members of a MEN-2 family, screening by molecular genetics of the ret gene enables one to identify the subjects at risk who bear the mutation. When no mutation is observed, a linkage analysis study may be proposed. (2) In the subjects at risk, early screening for the various types of endocrine lesions may then start in childhood and be performed using specific biological markers of MTC, pheochromocytoma and primary hyperparathyroidism, and particularly, basal and pentagastrin-stimulated calcitonin measurement, which is known to be the most sensitive marker for the monitoring of MTC. (3) This step of biological investigations enables the earliest possible treatment of any endocrine lesion detected before it is expressed clinically, thus improving the prognosis of MEN-2. When genetic screening cannot be performed, only annual clinical and biological monitoring remain available in all members of a family affected with MEN-2.

Drosophila Proteins↗
PubMed1997

[Outcome of 111 thyroid papillary carcinomas. Retrospective study from 1953 to 1994. Experience of Bergonié Institute].

The evolution of techniques has increased the number of diagnosed thyroid papillary microcarcinoma challenging the previous therapeutic guidelines. We have studied all thyroid cancers in our data base (from 1953 to 1994, N = 698). One-hundred and eleven were papillary microcarcinomas (none before 1967): 83 M0N0, 24 M0N+ et 4 M+. One-hundred and eight pathologic slides could be obtained and were checked by one of us (pathologist). The mean follow-up was 8.6 yr [1-28]. Two clinical and pathological features were different between M0N0 and M0N+ (groups: i) the sex-ratio, 12 vs 50% men (M0N0 vs M0N+, p < or = 0.0001), ii) the invasiveness of the tumor, 54/83 vs 20/24 (M0N0 vs M0N+, p = 0.01). All patients received a suppressing treatment by thyroid hormones (except lobectomy). The other treatments were: for 64/83 M0N0 a total thyroidectomy followed by a I131 treatment, for the remaining no I131 (15 partial thyroidectomies and 4 total thyroidectomies). None of the M0N0 patients displayed metastasis or cancer relapse. All patients M0N+ had a total thyroidectomy followed by a I131 treatment. Among the latter, I had a major node evolution, the death was attributed to the cancer at the age of 83 after a 6 yr long evolution. Among the 4 patients considered as metastatic. 1 was poorly differentiated. For the remaining 3, the thyroidal origin of the metastasis was not clear. In summary, the papillary microcarcinomas display a good prognosis if devoid of metastasis. We propose the following guidelines: a total thyroidectomy followed by a I131 treatment and suppressing treatment if clinical nodes, or non-encapsulated tumor or multifocal tumor. For solitary tumors, well encapsulated a lobectomy appears sufficient.

Adult↗
PubMed1996

Does functional alteration of the gonadotropic axis occur in endurance trained athletes during and after exercise? A preliminary study.

In men, the hypothalamic-pituitary-testicular axis controls the secretion of testosterone which, in this sex, is a major anabolic hormone. Physical exercise modulates testosterone concentration, affecting the whole axis by poorly understood mechanisms. We have reported in this preliminary study the short and long-term effects of exercise on the function of the gonadotropic axis in trained compared to untrained subjects. Environmental factors known to interfere with pituitary function were minimized. Four marathon and four sedentary men, were studied during 5 days successively using different combinations of two factors: duration and intensity of running tests. Day 0 (D0) was a rest day, and the exercises were: D1 and D2 brief (20 min), light (50% maximal heart rate, HRmax, D1) or intense (80% HRmax, D2), D3 and D4 prolonged (120 min) and light (50% HRmax, D3) or intense (80% HRmax, D4). Testosterone (free and total) and luteinizing hormone (LH) concentrations were measured before, during and after exercise. The baseline concentrations of plasma testosterone were lower in the long distance runners than in the sedentary group [41.8 (SEM 5.5) vs 64.5 (SEM 7.9) pmol.l-1, respectively; P < 0.05]. This phenomenon was centrally mediated as LH concentration was apparently inappropriately low [3.4 (SEM 0.4) vs 4.3 (SEM 1.0) UI.l-1; P > 0.05]. Light to moderate exercise did not modify testosterone and LH concentrations. Conversely, intense and prolonged exercise increased testosterone concentration [73.2 (SEM 9.0) vs 92 (SEM 11.0) pmol.l-1 in the long distance runners and sedentary group, respectively; P < 0.05] and lowered LH concentrations [2.1 (SEM 0.3) vs 3.4 (SEM 0.3) UI.l-1 in the long distance runners and sedentary group, respectively; P < 0.05 compared to D0, at the same time]. In our conditions of exercise, negative feedback of testosterone upon LH persisted, as positive feedback of low testosterone concentrations was apparently lacking (inappropriately low LH concentration with regard to low basal testosterone concentration).

Adult↗
PubMed1995

Pseudo-tumours of the thymus after correction of hypercortisolism in patients with ectopic ACTH syndrome: a report of five cases.

We report the cases of four patients with occult, and one patient with overt, ectopic ACTH syndrome. Cushing's syndrome was cured by removal of the ACTH secreting tumour, op'DDD, ketoconazole or bilateral adrenalectomy. Six to 14 months after remission of hypercortisolism, follow-up computed tomography or magnetic resonance imaging of the thorax revealed in all five patients an anterior mediastinal mass 3-5 cm in length that suggested a thymic carcinoma. Exploratory thoracotomy was performed in four cases and allowed the removal of an enlarged, but normal, thymus. Histological examination revealed no tumour but showed benign thymic hyperplasia with negative immunostaining for ACTH. Thymic enlargement spontaneously disappeared 11 months after its demonstration in the patient who did not undergo thoracotomy. The mechanism of this abnormality is thought to be thymic depletion resulting from high plasma cortisol concentrations followed by 'rebound' thymic hyperplasia when cortisol levels fall. Physicians involved in the management of patients with Cushing's syndrome must be aware of this entity in order to avert a diagnostic thoracotomy.

ACTH Syndrome, Ectopic↗