Biomedical subjects

Hong-Da Lin

Publications and source records attributed to Hong-Da Lin.

21 records · Page 2Linked to original sources

PubMed2002

A reappraisal of the ovine corticotropin-releasing hormone stimulation test in the differential diagnosis of Cushing's syndrome: a comparison with the standard high-dose dexamethasone suppression test.

BACKGROUND: We evaluated the diagnostic efficacy of the ovine corticotropin-releasing hormone (oCRH) stimulation test in the differential diagnosis of Cushing's syndrome and compared it with the standard high-dose dexamethasone suppression test. METHODS: Twelve healthy volunteers and 30 with Cushing's syndrome (12 Cushing's disease and 18 adrenal Cushing's syndrome) were enrolled. Plasma ACTH and cortisol levels were measured before and after an intravenous bolus of 100 microg oCRH. Plasma and urinary free cortisol were determined after standard 2-day high-dose dexamethasone suppression. RESULTS: Basal cortisol in 12 patients with Cushing's disease and 18 with adrenal Cushing's syndrome were higher than the control group (21.4 +/- 0.1 microg/dl vs. 22.3 +/- 0.5 microg/dl vs. 9.1 +/- 1.5 microg/dl; p < 0.01). In Cushing's disease, basal plasma ACTH value was significantly higher than those with adrenal disease (61.1 +/- 1.4 pg/ml vs. 6.2 +/- 4.5 pg/ml; p < 0.01). After oCRH, plasma ACTH and cortisol significantly increased, with a mean of 2.0 +/- 0.2-fold (range 1.0-2.4) and 1.6 +/- 0.1-fold (range 1.1-2.1), respectively over the basal values in patients with Cushing's disease, and 11 (90%) attained a significant ACTH (1.5-fold) or cortisol (1.2-fold) response. All except 2 (89%) with adrenal Cushing's showed no apparent change in response to oCRH. Dexamethsone suppressed urinary free cortisol by 90% in 8 (67%) with Cushing's disease, but all (100%) with adrenal Cushing's syndrome were resistant. No patient with Cushing's disease was refractory to oCRH and dexamethasone, while none with adrenal Cushing's syndrome was responsive to both. Combination of both tests could achieved a specificity of 100% for Cushing's disease and adrenal Cushing's, when these 2 tests gave concomitant positive or negative results, respectively. CONCLUSIONS: The oCRH test is a reliable examination in the differential diagnosis of Cushing's syndrome and is comparable to the high-dose dexamethasone test. A highest discrimination could be achieved when both are used.

ACTH Syndrome, Ectopic↗

PubMed2002

Thyrotropin-secreting pituitary adenoma with growth hormone hypersecretion.

A 34-year-old woman suffered from palpitation, easy sweating, heat intolerance, increased appetite, irregular menstrual cycle and hand tremor for 1 year. Thyroid function tests showed elevated serum thyroxine (T4), tri-iodothyronine (T3) and thyrotropin (TSH). Computerized tomography (CT) revealed pituitary tumor with supraseller extension. Thyrotropin releasing hormone (TRH) test showed blunted TSH response with elevated baseline level and paradoxical growth hormone (GH) response with elevated baseline level. T3 suppression test (T3 60 microg per day x 10 days) showed no inhibition of TSH (11.1 microU/mL, normal range < 6.2 microU/mL). She received transphenoidal approach and removal of tumor which measured 0.5 x 0.3 x 0.2 cm. Histopathologically, it was a pituitary adenoma which was immunoreactive for TSH, GH, follicular stimulating hormone (FSH) and luteinizing hormone (LH). To our knowledge, this case is the first case of TSH-secreting pituitary adenoma in Taiwan.

Adenoma↗

PubMed2002

The relationship between morning serum cortisol and the short ACTH test in the evaluation of adrenal insufficiency.

BACKGROUND: Morning serum cortisol examinations and short corticotropin (ACTH) tests are popular screening tests for unstressed patients suspected of having adrenal insufficiency. However, the correlation between morning serum cortisol and the peak cortisol response in the short ACTH test after intravenous injection of ACTH has not been studied before. This retrospective study examined the relationship among the mean basal morning cortisol level, the single random morning cortisol level and the peak cortisol level in the short ACTH test in evaluation of adrenal insufficiency. METHODS: In this retrospective study, we examined the relationship among the mean basal morning cortisol level and the peak cortisol level stimulated by intravenous injection of 250 microg synthetic ACTH in 106 unstressed patients with proven or suspected hypothalamic-pituitary-adrenal disease. Plasma cortisol levels were determined by radioimmunoassay. The correlation of the basal morning cortisol to the short ACTH test was determined by linear regression analysis. The ACTH test was analyzed using the receiver operating characteristic (ROC) curve method, and the cut-off points for various sensitivity and specificity were calculated. RESULTS: The mean basal is highly correlated to peak cortisol response in the ACTH test (r = 0.7724, p < 0.0001). Iatrogenic Cushing's syndrome, caused by ingestion of herbs with illegal steroid additives, was the most common cause (60%) of adrenal insufficiency in the 52 patients with subnormal result. A mean basal morning serum cortisol of > or = 300 nmol/L excluded the possibility of adrenal insufficiency, and a level of < 110 nmol/L suggested adrenal insufficiency. A mean basal cortisol level of > or = 234 nmol/L predicted a normal cortisol response in the ACTH test with optimal sensitivity (80.6%) and specificity (91.4%). CONCLUSIONS: The mean morning cortisol level is a cost-effective screening test in predicting the results of the ACTH test. A mean morning cortisol level > or = 300 nmol/L in suspicious cases of adrenal insufficiency which are not due to acute central etiologies excludes the possibility of subnormal cortisol response to ACTH; whereas a level < 110 nmol/L is likely to have subnormal cortisol response to ACTH. The short ACTH test or insulin tolerance test should be performed in patients with a morning cortisol level 300 nmol/L or with clinical symptoms highly suggestive of adrenal insufficiency.

Adolescent↗