The effects of pressure induced ischemia on the retina were studied by means of Electroretinogram(ERG) and Electron microscopy. Acute ischemias were induced in the cat's eyes by raising the intraocular pressure over the systolic pressure for 90 minutes in group one and 3 hours in group two. ERGs and OPs(Oscillatory potentials) were recorded 1 hour. 1 day, 3 days, 7 days and 14 days after prsssure-induced ischemia, respectively. The eyes were enucleated 1 hour, 1 day, 3 days, 7 days and 14 days after ischemia for evaulation of structural damage of the retina. The amplitudes of a-, b-waves and the summed amplitudes of OPs(SOP) were decreased to 57.4%, 51.9% and 45.2% of control values at one day after ischemia and then recovered to 80%, 68.8% and 59% at 14 days after ischemia in group one. In group two, the amplitudes of a-, b-waves and the summed amplitudes of OPs appeared to flat at 1 hours after ischemia and then recovered to 50%, 50% and 30.7% of control values at 14 days after ischemia. In group one, electron microscopic study revealed generalized retinal damages including retinal edema and the pyknosis of the nucleus. And these changes seemed to be recovered gradually until two weeks after damages. In group two, the retina received more severe ischemic damages than group one, such as destruction of photoreceptors, necrosis of photoreceptor, bipolar cells and ganglion cells on one day after ischemia. After 2 weeks, the loss of photoreceptors and the pigment epithelial migration into the inner retinal layer were noted. In conclusion, the ERG study revealed that the OPs was the most vulnerable components to the ischemia and the histopathological study showed that the photore ceptors received more severe damage from the retinal ischemia than the other components.
Animals ; Blood Pressure ; Cats* ; Ganglion Cysts ; Intraocular Pressure ; Ischemia* ; Microscopy, Electron ; Necrosis ; Papilledema ; Retina ; Retinaldehyde

PURPOSE: To evaluate the diagnostic value of radiologic studies in the Cushing's disease MATERIALS AND METHODS: We analyzed retrospectively the CT(n=19, dynamic CT was not perfomed), MR (n=23, dynamic MR in 2 cases), and the results of inferior petrosal sinus sampling(IPSS)(n=13) in 25 patients(19 women, 6men, age range 16-58, mean 32.2) with pathologically-confirmed ACTH secreting pituitary adenoma. We analyzed the radiologic findings and determined how accurately each method could detect and lateralize the lesion within the pituitary gland. The results were compared with the surgical findings and with each other. RESULTS: Seven patients(28%) out of 25 had macroadenomas and the lesions were detected and correctly diagnosed by CT and MR in all. Eighteen patients(72%) had microadenoma. In patients with microadenoma the sensitivity was 38.5%(5/13) in CT, 64.7%(11/17) in MR, 90.9%(10/11) in IPSS. In two patients with dynamic MR, in whom the conventional Gd-enhanced MR showed false negative results, the lesions were detected as low signal intensity mass and correctly lateralized. Considering the results of both MR and IPSS, the sensitivity increased up to 94.1%(17/18). CONCLUSION: Considering the invasiveness of IPSS, Gd-enhanced MR, preferably dynamic, seems to be an imaging modality of choice in Cushing's disease. Combined use of IPSS in selected patients further increases the accuracy of diagnosis and lateralization.
ACTH-Secreting Pituitary Adenoma ; Diagnosis ; Female ; Humans ; Pituitary Gland ; Retrospective Studies

PURPOSE: The purpose of this study was to evaluate basic experimental data for the clinical application of a self-expandable stainless steel intravascular Hanaro spiral stent. MATERIALS AND METHODS: For evaluation of thephysical properties of the Hanaro stent, hoop strength, radioopacity, longitudinal flexibility, and foreshortening were measured. Twelve intravascular Hanaro spiral stents were placed in the infrarenal abdominal aorta (n=6) and comon iliac artery (n=6) in six mongrel dogs. Angiography and light microscopic examination were performed after one, two and eight months of placement of the stents. RESULTS: The stent had good radioopacity and was deployed with minimal foreshortening. Hoop strength of a 6mm-interval bend was found to be superior to that of 8mm- and 10mm-bend stent. On angiography the patency rate and thrombosis rate were 100% and 0% in the abdominal aorta and 50% and 50% in the common iliac artery, respectively. Minimal corrosion was seen in all stents, and they appearedto be biocompatible. The stent wires were covered with well-developed neointima which after one month had mostly fibroblast and collagen tissue; the thickness of the neointima increased gradually during a period of eightmonths. At the end of that period, collagen fibres in the neointima were denser and showed a more paralled configuration than at one month. CONCLUSION: The Hanaro stent has good physical properties and also has a high patency rate, and good biocompatibilities. The stent may therefore be reliably and safely deployed in the humanvascular system.
Angiography ; Animals ; Aorta, Abdominal ; Atherosclerosis ; Collagen ; Corrosion ; Dogs ; Iliac Artery ; Neointima ; Pliability ; Stainless Steel ; Stents ; Thrombosis

BACKGROUND: Minimal-flow anesthesia can meet the demands of a modern society that is more sensitive to environmental protection and economic burdens. This study compared the safety and efficacy of minimal-flow desflurane anesthesia with conventional high-flow desflurane anesthesia for prolonged laparoscopic surgery. METHODS: Forty-six male patients (ASA physical status II or III) undergoing laparoscopic urologic surgery for more than 6 hours were randomly divided into two groups: the high-flow (HF) group and the minimal-flow (MF) group. The HF group was continuously administered a fresh gas flow of 4 L/min. In the MF group, a fresh gas flow of 4 L/min was administered for the first 20 minutes and was thereafter lowered to 0.5 L/min. Inspiratory and expiratory desflurane concentrations, respiratory variables, and hemodynamic variables were continuously monitored during administration of anesthesia. Measurements of carboxyhemoglobin (COHb) concentration and arterial blood gas analysis were performed every 2 hours during anesthesia. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen (BUN) and creatinine were measured on the first and second day after the surgery. RESULTS: Demographic data and duration of anesthesia were not different between the two groups. Significant differences were not observed between the two groups in terms of hemodynamic variables, respiratory variables, and inspiratory and expiratory desflurane concentrations. Inspiratory O2 concentration was maintained lower in the MF group than in the HF group (43-53% vs. 53-59%; P < 0.05). Compared with the HF group, COHb concentrations was higher (P < 0.05), but not increased from the baseline value in the MF group. Serum AST, ALT, BUN, and creatinine were not significantly different between the two groups. CONCLUSIONS: In prolonged laparoscopic surgery, no significant differences were found in safety and efficacy between minimal-flow and high-flow desflurane anesthesia.
Alanine Transaminase ; Anesthesia ; Aspartate Aminotransferases ; Blood Gas Analysis ; Blood Urea Nitrogen ; Carboxyhemoglobin ; Natural Resources ; Creatinine ; Hemodynamics ; Humans ; Isoflurane ; Laparoscopy ; Male