Two cases of Cushing's syndrome diagnosed by IPSS with normal or low plasma ACTH / 대한내과학회지

Cushing's syndrome results from prolonged exposure to high levels of glucocorticoid hormones. ACTH-dependent Cushing's syndrome accounts for about 85% of endogenous causes. Autonomous pituitary ACTH secretion, called Cushing's disease, is responsible for 80% of these causes, whereas ectopic ACTH secretion is responsible for 20% of them. Appropriate therapy of patients with Cushing's syndrome depends on accurate diagnosis and classification of the disorder. In addition to the history and clinical evaluation, the laboratory evaluation of a patient with Cushingoid appearance is necessary to establish the diagnosis and determine the cause of hypercortisolism. A major problem in the differential diagnosis of ACTH-dependent Cushing's syndrome is distinguishing Cushing's disease from the ectopic ACTH syndrome. Both entities can have similar clinical and laboratory features. In addition, both pituitary microadenoma and ectopic ACTH-secreting tumors may be radiologically occult. Bilateral inferior petrosal sinus and peripheral vein catheterization with simultaneous collection of samples for measurement of ACTH is one of the most specific tests available to localize the source of ACTH production. We report two cases of Cushing's syndrome diagnosed by inferior petrosal sinus sampling associated with normal or low ACTH levels on routine basal hormone assay.

Detection of Pyrazinamide Resisitance in Mycobacterium Tuberculosis by Sequencing of pncA Gene / 결핵

BACKGROUND: Examining the biological susceptibility of Mycobacterium tuberculosis to pyrazinamide (PZA) in vitro is very difficult as PZA is inactive under normal culture conditions. The susceptibility test, an enzyme assay for Pzase activity, and a genetic test for pncA gene mutations, were performed in order to predict PZA resistance. METHODS: 28 cultured clinical isolates of Mycobacterium tuberculosis were tested. The biological susceptibility was performed by the absolute concentration method using Lowenstein-Jensen media. The PZase activity was tested by means of Wayne's method. A 710-bp region includes the entire open reading frame of pncA was amplified and sequenced. RESULTS: All six strains with positive PZase activity exhibited no pncA mutations with one strain showing a false resistance in the biological susceptibility test. Among the 22 strains with no PZase activity, 21 exhibited showed pncA mutations. In the biological suscaptibility test, 20 strains were resistant, and one was susceptible, and the other failed to test. The mutation types varied with ten missense, one silent and one nonsense mutation 1 slipped-strand mispairing, and 6 frameshift mutations. Three strains had an adenine to guanine mutation at position - 11 upstream of the start codon. CONCLUSION: The mutation at the pncA promotor region is frequent at -11 upstream position. Automatic sequencing of pncA is a useful tool for rapid and accurate detection of PZA resistant M.tuberculosis, and for demonstrating the epidemiological relatedness of the PZA-resistant M.tubersulosis strains.

Ultra-Structures And 14C-mannitol Transport Study of Human Nasal Epithelial Cells using ALI Culture Technique / 결핵

BACKGROUND: The information on nasal transport and the metabolism of peptides have been obtained from pharmacokinetic investigations in experimental animals. However, there are no transport and metabolic studies of human nasal epithelial cells. In this study, the permeability characteristics and the metabolic properties of in vitro human nasal cell monolayers were investigated. Material and METHODS: Normal human inferior nasal conchal tissue samples were obtained from patients undergoing endoscopic nasal cavitary surgery. The specimens were cultured in a transwell using an air-liquid interface (ALI) culture, and the transepithelial electrical resistance (TEER) value of the blank filter and confluent cell monolayers were measured. To determine the % leakage of mannitol, 4µmol 14C-labelled mannitol was added and the % leakage was measured every 10 minute for 1 hour. RESULT: Human nasal epithelial cells in the primary culture grew to a confluent monolayer within 7 days and expressed microvilli. The tight junction between the cells was confirmed by transmission electron microscopy. The TEER value of the blank filter, fifth day and seventh day reached 108.5 ohm.cm2, 141 ohm.cm2 and 177.5 ohm.cm2, respectively. Transcellular % leakage of the 14C-mannitol at 10, 20, 30, 40, 50 and 60 minutes was 35.67±5.43, 34.42±5.60, 32.75±5.71, 31.76±4.22, 30.96±3.49 and 29.60±3.68 %, respectively. CONCLUSION: The human nasal epithelial monolayer using ALI using techniques is suitable for a transcellular permeability study. The data suggests that human nasal epithelial cells in as ALI culture technique shows some promise for a nasal transport and metabolism study.

Telomerase Activity in Primary Lung Cancers / 결핵

BACKGROUND: Telomerase enzyme activity is not detected in most normal cells, a phonomenon believed to be associated with limitations on cellular proliferation. Since this activity is detected in nearly all human tumor, including lung cancers, it has been suggested that telomerase activation may be coupled to acquisition of malignant phenotype. In this study, we determined whether telomerase activity was associated with tumor pathologic stage. METHODS: Primary tumor specimens obtained by bronchoscopic biopsies from 33 patients were analyzed. Telomerase activity was measured by means of a modified Telomeric Repeat Amplication Protocol(TRAP) assay. RESULTS: Telomerase activity was detected in 23 of the 27 non small cell lung cancer and 5 of 6 small cell lung cancer. A few primary tumors did not appear to have detectable telomerase activity. Positive associations were found between the telomerase-positive rate and tumor stage(p<0.05). CONCLUSION: High telomerase activity is detected frequently in primary lung cancers that exhibit high tumor cell proliferation rates and advanced pathologic stage.