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Biomedical subjects

P Thomopoulos

Publications and source records attributed to P Thomopoulos.

At least 19 recordsLinked to original sources
PubMed1999

[Pituitary metastases. 3 cases].

OBJECTIVE: Review cases with hyothalamo-hypophyseal metastases which raise complex therapeutic situations. PATIENTS AND METHODS: Files of patients hospitalized from 1992 to 1996 at the Cochin Hospital Endocrinology unit were compared with data reported in the literature. RESULTS: We had patients with pituitary metastases from breast cancer and 69 cases have been reported in the literature: 72 patients, 57% men and 43% women, mean age 57.2 +/- 12.3 years. The primary tumor was identified in 58.3% of the cases. The primary cancer was unknown and revealed by the pituitary metastasis in 41.7% of the cases. The primary tumor was a breast cancer in 31.9% of the cases, and lung cancer in 30.5%. The main clinical signs were vision disorders (40.3%) and diabetes insipisus (29.1%). The principal differential diagnosis was hypophyseal adenoma. Short term prognosis was not good. DISCUSSION: These data are in agreement with the older literature excepting the high prevalence of primary cancers revealed by pituitary metastasis, probably a result of progress in hypophyseal exploration techniques. CONCLUSION: The prevalence of pituitary metastasis will continue to increase with longer survival in cancer patients. Metastasis should thus be entertained as a possibility in patients with a hypothalamo-hypophyseal tumor, particularly after the age of 59, in order to hasten diagnosis and provide early treatment.

Aged↗
PubMed1999

[Hepatic ischemia and hypophyseal macroadenoma].

We report the first case of recurrent hepatitis secondary to a pituitary macroadenoma in a 55-year old man. Liver ischemia is thought to be the main consequence of episodes of acute adrenal insufficiency. Sudden acute adrenal insufficiency was due to enlargement of the sella content secondary to several microhemorrhages in the macroadenoma.

Acute Disease↗
PubMed1998

[Thyroid hormone production and its regulation].

Thyroid gland fulfills two functions. On one hand, it synthesizes and builds up stocks of thyroid hormones in thyroglobulin molecules of the colloid in its follicles, such as they can maintain the hormonal secretion during several days and even weeks. To do this, it captures and concentrates plasma iodide through a specific membrane transporter and it oxidizes iodide through the action of thyroperoxidase and H2O2. This makes it able to bind to tyrosine residus of thyroglobulin. Then, the iodotyrosines can form the thyroid hormones (T4 and T3) by a coupling reaction. On the other hand, thyroid secretes the hormones after internalization and proteolysis of thyroglobulin. All the steps of synthesis and secretion are regulated by pituitary TSH, through a negative feed-back action of T4 and T3. Thus, any increase or decrease of circulating thyroid hormones induces the opposite modification of TSH. In addition, an important fraction of plasma and tissue T3 is produced through the extrathyroidal monodeiodination of T4 by enzymes (5' deiodases) which are regulated by the nutritional status and by thyroid hormones.

Humans↗
PubMed1998

[Diabetes insipidus with a hypothalamo-hypophyseal morphologic anomaly during a pregnancy].

BACKGROUND: Diabetes insipidus is uncommon in pregnancy. Despite physiological modifications in hydroelectrolytic balance during normal pregnancy, the capacity of the kidney to concentrate urine is preserved, partially due to lower vasopressin secretion. CASE REPORT: A young woman developed diabetes insipidus during the third trimester of normal pregnancy. The disease regressed totally after delivery. However, magnetic resonance imaging revealed a persistent expansive intrasellar image with a high-intensity signal. DISCUSSION: Onset of diabetes insipidus is usually rapidly progressive in pregnancy. Occurring generally during the third trimester in normal pregnancies, diabetes insipidus is generally well tolerated and responds to dDAVP, usually without pituitary abnormally, and regresses after delivery. Two types are distinguished: partially latent diabetes insipidus occurring during pregnancy and due to a central rather than nephrogenic origin; and excessive vasopressinase activity leading to diabetes insipidus usually associated with liver anomalies and high frequency of pre-eclampsia. During normal pregnancy, the size of the anterior pituitary increases and the normal high-intensity signal in the posterior pituitary seen on MRI usually regresses or disappears. In diabetes insipidus, the posterior pituitary hypersignal image generally disappears, reflecting reduced vasopressin storage. Few observations of diabetes insipidus occurring during pregnancy have been reported with morphological explorations. Most have described a "normal" aspect of the pituitary, specifically in the post partum period. In our patient, the weak vasopressin response to the end of water restriction at post partum when the diabetes insipidus symptoms had disappeared would suggest partial central diabetes insipidus revealed by pregnancy. Other pathologies involving this region could also be involved due to the unusual and persistent sellar image, with an expansive process showing a high intensity signal on MRI. An asymptomatic craniopharyngioma cyst was hypothesized and would be more compatible with the observed symptoms.

Adult↗
PubMed1998

[POEMS syndrome with primary adrenocortical insufficiency].

BACKGROUND: POEMS syndrome is a multisystem disorder. It usually presents as severe polyneuropathy and monoclonal gammapathy associated with endocrinopathies, organomegaly, skin hyperpigmentation. CASE REPORT: A patient with POEMS syndrome developed primary adrenocortical deficiency revelated by asthenia and hyperpigmentation. Hydrocortisone replacement therapy produced a rapidly beneficial effect on asthenia and hyperpigmentation. DISCUSSION: Although asthenia and skin pigmentation are common in POEMS syndrome, adrenocortical deficiency is seldom reported. This endocrinopathy might be underestimated in POEMS patients. We suggest systematic screening with a rapid ACTH test in all POEMS patients in order to detect underlying adrenal deficiency.

Adrenal Cortex Function Tests↗
PubMed1998

[Failure of synthcen to diagnose corticotropin insufficiency].

It is commonly believed that a normal cortisol response to exogenous ACTH (synacthen test) reliably indicates, with the exception of states of acute ACTH deprivation, the integrity of hypothalamic-pituitary-adrenocortical function. Published evidence has shown that the synacthen test is not sensitive enough to reveal partial ACTH deficiency leading to a subnormal ACTH response to stress. We report a patient who maintained a normal response to exogenous ACTH stimulation despite symptomatic chronic ACTH deficiency in unstressed conditions. A normal cortisol response in the synacthen test does not therefore exclude the possibility of clinically relevant ACTH deficiency.

Adrenal Insufficiency↗
PubMed1998

[Medical treatment of secretory hypophyseal adenomas].

The main indication for medical treatment of the secretory pituitary adenomas is macroprolactinoma. In this case, bromocriptine therapy obtains better results than surgery, by a life-long administration. New dopaminergic drugs with better tolerance and a longer half-life than bromocriptine will probably improve compliance to treatment. Besides, somatostatin analogs, especially the slowly-released preparations, administrated once or twice per month, often obtain normalization of hormonal production in GH (growth hormone) or TSH (thyrotropin) secreting adenomas after surgical failure and are used in complement to radiotherapy.

Adenoma↗
PubMed1997

[Differentiated thyroid carcinomas manifesting as toxic adenoma].

BACKGROUND: Hot thyroid nodules are generally benign. We report two exceptional cases of thyroid carcinomas mimicking toxic adenomas. CASE REPORTS: A 35-year-old man and a 55-year-old woman had thyroid carcinoma behaving as an autonomously hyperfunctioning nodule. DISCUSSION: Only twenty similar cases have been reported in the literature. While a hot nodule on radio-iodine scan is unlikely to be malignant, the possibility of carcinoma should not be overlooked. Surgery should therefore be the preferred treatment of toxic adenoma.

Adult↗
PubMed1997

[Assay of salivary cortisol. An interesting method for exploring the adrenal cortex].

AN INTERESTING METHOD FOR PATIENTS AND PHYSICIANS: Measurement of salivary cortisol has not modified the investigation of hospitalized patients but offers very original possibilities for exploring outpatients. REPEAT MEASUREMENTS AND STIMULATION TESTS: As for serum cortisol levels, repeat measurements or stimulation tests are required for reliable evaluation of salivary cortisol. SEVERAL APPLICATIONS: Salivary cortisol level can be an appropriate tool in screening for adrenal insufficiency, using the short ACTH injection test, evaluating hypercorticism through the circadian cycle of cortisol and overnight dexamethasone suppression test either at the physician's office or in the patient's home. In addition, long-term follow-up is possible for outpatients investigated or treated for Cushing's syndrome.

Adrenal Cortex Function Tests↗
PubMed1996

[Lymphocytic hypophysitis: a reality].

Lymphocytic hypophysitis is a rare entity; we report here three cases. This condition usually occurs in women during pregnancy or in the post-partum period. Pituitary enlargement is associated with complete or partial hypopituitarism. The difficulty in diagnosis is well illustrated by our cases and results from the similarity between the clinical and biological signs of adenoma and hypophysitis. Circulating antipituitary antibodies are not constantly found and are nonspecific, evidence only of the autoimmune nature of hypophysitis. Thus the diagnosis has to be undertaken in all suspected cases in pregnant women or during the post-partum period. The clinical course may be very long, emphasizing the need for rigorous long-term observation. The pituitary gland is commonly enlarged and homogenous in lymphocytic hypophysitis, but in our third case the enlargement was heterogeneous with associated cyst formation. We suggest that the inflammatory process could have been maintained by the presence of cysts. Finally, corticosteroids are the therapy of choice in the inflammatory stage and should be undertaken as soon as the diagnosis has been established. Regular surveillance is required.

Adult↗
PubMed1996

Overnight dexamethasone suppression test: comparison of plasma and salivary cortisol measurement for the screening of Cushing's syndrome.

The overnight 1-mg dexamethasone suppression test is a very good screening test for subjects suspected of having Cushing's syndrome. To simplify the procedure, we evaluated the 1-mg dexamethasone suppression test with measurement of salivary cortisol. We performed this test with plasma and salivary cortisol measurements in 27 patients with Cushing's syndrome and 64 normal controls. The sensitivity and specificity of plasma cortisol measurements were 100% and 87%, respectively, for a cut-off point of 100 nmol/l, in accordance with previous studies. The results of salivary cortisol showed the absence of overlap between the two groups, with a sensitivity and specificity of 100% for a cut-off point of 2.8 nmol/l. On a larger series, however, one might occasionally miss the diagnosis of a patient with Cushing's syndrome. Therefore, we favor a cut-off point of 1.9 nmol/l, the sensitivity remaining at 100% and the specificity being 94%. In conclusion we recommend the overnight dexamethasone suppression test with measurement of salivary cortisol as a screening test for Cushing's syndrome.

Adult↗
PubMed1995

Long-distance and long-term follow-up of a patient with intermittent Cushing's disease by salivary cortisol measurements.

Salivary cortisol is an excellent indicator of the plasma free cortisol concentration in normal and pathological situations. We took advantage of its ease of sampling, allowing multiple collections at home, to follow the course of a patient with Cushing's disease living in North Africa. This 48-year-old woman presented with a clinically moderate hypercortisolism caused by a large basophilic pituitary adenoma. Bilateral extension to the cavernous sinuses precluded surgical therapy. She went into spontaneous remission based on clinical signs as well as biochemical findings. During the following 2 years she demonstrated intermittent relapses that were treated by radiotherapy (50 Gy), followed by ketoconazole and then o-paraprime-dichloro-diphenyl-dichloroethane (Op'DDD). After a prolonged clinical remission, Cushing's syndrome again became active. Bromocriptine was started without effect and a new treatment with Op'DDD was began. Evaluation and follow-up were performed during hospitalizations and mainly through the measurements of salivary cortisol in more than 100 samples sent from North Africa by air mail to our department in Paris. Thus we were able to demonstrate intermittent overproduction of cortisol before any treatment, with periods of normal and even low values, and to follow the efficacy of therapy and to detect the relapses. We conclude that measurement of salivary cortisol is a valuable tool in difficult clinical situations such as intermittent hypercortisolism and remoteness between the patient and hospital.

Africa, Northern↗
PubMed1995

ADP and ATP activate distinct signaling pathways in human promonocytic U-937 cells differentiated with 1,25-dihydroxy-vitamin D3.

We investigated the effects of purinergic P2 agonists on cell adhesion, as well as the signaling pathways involved, in U-937 human promonocytic cells differentiated to a more mature monocytic phenotype with 1,25-(OH)2-vitamin D3. In cell adhesion studies, ATP was more potent than ADP, whereas ADP showed greater efficacy. The time course of the intracellular calcium concentration ([Ca2+]i) response to ATP was biphasic (a spike followed by a plateau), whereas ADP evoked a plateau after a time lag of several seconds. The spike [Ca2+]i response evoked by ATP was due to both myo-inositol-1,4,5-trisphosphate-induced Ca2+ mobilization and influx, whereas the ADP effect was Ca2+ influx dependent. Moreover, ADP and ATP activated distinct Ca2+ influx mechanisms, as shown by Mn2+ quenching of the fura-2 signal, which was slow and long-lasting for ADP but rapid for ATP. Treatment with phorbol dibutyrate shifted the EC50 of the [Ca2+]i spike response to the right and abolished the plateau response. Accordingly, phorbol dibutyrate inhibited the ADP-evoked response but only partly inhibited the ATP-evoked Ca2+ influx. cAMP-raising agents had no effect on the [Ca2+]i spike or on Ca2+ influx but delayed or transiently inhibited the plateau phase. The plateau response thus appears to be independent of the spike response, because it can be directly evoked by ADP and undergoes distinct regulation. This suggests that ADP and ATP activate U-937 cells through distinct signaling pathways, probably involving specific receptors.

Adenosine Diphosphate↗