Rathke cleft cyst: MR and biomedical analysis of cyst content

PURPOSE: At least one type of Rathke cleft cyst has unique MR findings, specifically, high intensity on T1-weighted images and iso- to low intensity on T2-weighted images relative to white matter. To clarify the influence of cyst content on MR images, we analyzed the cyst content by biomedical methods after surgical removal. METHOD: We studied five patients diagnosed with Rathke cleft cyst, whose MR images showed high intensity on T1-weighted images and iso- to low intensity on T2-weighted images. After surgery, total protein and cholesterol levels were quantified, and correlations of protein and cholesterol content with T1 and T2 signal intensities were performed in vitro. RESULTS: All five cysts had very high concentrations of protein (11,700-26,600 mg/dl, mean 17,940 mg/dl) with nearly no cholesterol (at most 2.0 mg/dl). Along with increases in protein concentration in vitro, the signal intensity of T1-weighted images increased, while that of T2-weighted images decreased. In contrast, the cholesterol concentration sequence influenced the signal intensity of neither T1- nor T2-weighted images. CONCLUSION: The unique MR finding of Rathke cleft cysts--high signal intensity on T1-weighted images and low signal intensity on T2-weighted images--might depend mainly on protein concentration, not on cholesterol.     

Endosonography during endoscopic mucosal resection to enhance its safety

BACKGROUND: We have performed endoscopic mucosal resection of the esophagus (172 cases), stomach (102 cases), and colon (28 cases) using a transparent plastic cap. Because the lesion-bearing mucosa is suctioned up inside the cap under endoscopic suction, the mucosa should be dissected sufficiently from the proper muscle layer to prevent perforation. METHODS: To avert the risk of perforation, we introduced endosonographic assessment of submucosal dissection (47 cases). In all cases, just keeping the ultrasonic probe on the surface of the mucosa allowed us to evaluate whether the mucosal lesion was lifted up sufficiently from the proper muscle layer after local saline injection. RESULTS: It was possible to confirm that the muscle layer was kept outside the strangulating snare by the same procedure (32 of 37 cases, 86.5%). CONCLUSIONS: We experienced five muscular resections in cases without the ultrasonic probe and no muscular resection with the ultrasonic probe. Thus we recommend endosonographic assessment during endoscopic mucosal resection to enhance its safety.     

Total Esophagectomy versus Proximal Esophagectomy for Esophageal Cancer at the Cervicothoracic Junction

To investigate the adequate extent of esophagectomy and lymphadenectomy for an esophageal cancer localized at the cervicothoracic junction, the mortality and morbidity rates, survival rates, and patterns of recurrence were retrospectively analyzed in two groups—14 patients who underwent total esophagectomy with or without laryngectomy and 15 patients who underwent proximal esophagectomy with or without laryngectomy—at Kurume University Hospital from 1981 to 1996. Proximal esophagectomy with or without laryngectomy resulted in a lower hospital mortality rate and better overall survival for patients who underwent curative esophagectomy compared with total esophagectomy with or without laryngectomy. Multivariate analysis indicated that the extent of esophagectomy (total esophagectomy versus proximal esophagectomy) was not a prognostic factor. The incidence of recurrence was not different between the two groups. Lymph node metastasis or recurrence from such esophageal cancers was localized to the neck and upper mediastinum. For an esophageal cancer localized at the cervicothoracic junction, therefore, proximal esophagectomy with or without laryngectomy and with cervical and upper mediastinal lymphadenectomy could be better indicated for preselected patients.     

Aprindine blocks the sodium current in guinea-pig ventricular myocytes

Summary Aprindine is a class Ib antiarrhythmic agent. We studied effects of aprindine (3 µmol/l) on the Na⁺ current using whole cell voltage clamp (tip resistance = 0.5 , [Na]_i and_o = 10 mmol/l at 18°C). Aprindine revealed tonic block (Kd_rest = 37.7 µmol/l, Kd_i = 0.74 µmol/l; n = 4). Aprindine, shifted inactivation curve to hyperpolarizing direction by 11.4 ± 3.5 mV (n = 4) without changes in slope factor. In the presence of 3 µmol/l aprindine, aprindine showed phasic block, i.e., duration-dependent block at 2 Hz (64% ±3070 at 1.5 ms, 82%±6% at 20 ms, 93%±7% at 200 ms; n = 4). Short single prepulse also produced aprindine-induced phasic block (12% at 1.5 ms, 22% at 100 ms; n = 2). After removal of fast inactivation of Na⁺ current by 3 mmol/l tosylchloramide sodium, aprindine revealed phasic block, independent of holding potential. The recovery time constant from aprindine-induced phasic block was 4.8 s at holding potential = –100 mV and 5.0 s at holding potential = –140 mV. This use-dependent block of aprindine had pH dependency. Under acidic condition (pH 6.0), 3 µmol/l aprindine showed smaller use-dependent block (14% ± 7% at 2 Hz; n = 4) comparing with either at pH 7,4 (68% ± 13%; n = 4) or at pH 8.0 (90% ±12%; n = 4).The results suggest that aprindine could bind to the receptor via activation process through channel pore, resulting in decrease of Na⁺ current, and egress from the receptor through the lipid bilayer. These effects might be attenuated under acidic condition due to changes in intracellular ratio of charged to neutralized form of drug molecule. Send offprint requests to: R. Sato at the above address     

Surgical treatments for 7 pituitary adenomas in multiple endocrine neoplasia type 1

We analyzed 7 pituitary adenomas in patients with multiple endocrine neoplasia type 1 (MEN1). Their incidence was 1.6% among 450 patients with pituitary adenomas which had been treated surgically in our department between 1978 and 1999. The age, gender, symptoms, type of hormone secretion, pathological and operative findings in the MEN1 patients were not apparently different from those in the non-MEN1 patients. Incidence of non-functioning pituitary adenomas, however, was more frequently encountered in our series than that in previous reports among Caucasian people. One patient who had 5 previous operations for the MEN tumors died following postoperative subarachnoid hemorrhage. Four of the seven patients presented initial symptoms related to pituitary adenomas and increased serum Ca level was retrospectively recognized in three of the four at the time of treatment for the pituitary adenomas.     

Comparison of two-year and five-year tamoxifen use in Japanese post-menopausal women

AIM: Large multicenter, randomized trials have revealed the advantages of using tamoxifen for 5 years vs 2 years in breast cancer patients. The aim of this report is to confirm the optimal duration of tamoxifen administration in a study of Japanese breast cancer patients. METHODS: Japanese post-menopausal estrogen receptor-positive breast cancer patients treated with mastectomy were randomly assigned to either a 5-year or 2-year course of tamoxifen. The primary endpoint was disease-free survival, with secondary endpoints of overall survival and a reduction in the development of metachronous contra-lateral breast cancer. RESULTS: A total of 256 breast cancer patients were randomized to a 5-year or 2-year tamoxifen administration group. After a median follow-up time of 81 months, there were no significant differences seen in terms of disease-free or overall survival (p=0.65 and 0.56, respectively). Furthermore, the impact of the 5-year use of tamoxifen on the development of contra-lateral breast cancer did not reach statistical significance (p=0.0511). However, 5-year tamoxifen use was closely associated with gynaecological complications (p=0.0081). CONCLUSION: We could not show a beneficial effect of using tamoxifen for 5 years over 2 years in Japanese estrogen receptor-positive patients. This is likely due to the small number of patients enrolled in our study; however, racial disparity may influence this result. A reevaluation is necessary to study the advantages of the 5-year use of tamoxifen in the Japanese racial subgroup.     

Geographic Clustering Patterns in Mortality from Biliary Tract Cancer in Japan

We calculated the standardized mortality ratios (SMRs) of biliary tract cancer (BTC) in Japan from 1981 to 1990 and statistically analyzed the results according to 333 Secondary Areas of Medical Care, as well as sex and subsite [gallbladder cancer (GBC) and extrahepatic bile duct cancer (BDC)], in order to examine geographic clustering patterns of BTC. In GBC in both sexes, the Secondary Areas of Medical Care with high SMRs were clustered in the eastern part of Japan. In BDC in both sexes, the Areas with high SMRs were clustered between the northern and eastern parts of Japan. In comparison with GBC, this clustering favored the northern part of Japan. In males, the clustering pattern in mortality from BTC was mainly due to the occurrence of BDC. In females, the clustering pattern in mortality from BTC reflected that of GBC. The clustering of BTC, especially GBC, seems to be related to the distribution of plains, basins, and rivers.     

A case of deep soft tissue leiomyoma: CT and MRI findings

A 25-year-old man presented with a firm tissue mass of the right elbow and intermittent pain. CT showed a dumbbell-shaped soft tissue mass with foci of dense calcification in the muscular layer of the triceps brachii muscle and subcutaneous tissue. The tumor showed slightly higher signal intensity on T1-weighted images and markedly higher intensity on T2-weighted images compared with the surrounding muscle. Prominent enhancement was present after the intravenous injection of Gd-DTPA. Histopathological examination of the resected specimen revealed a deep soft tissue leiomyoma.