DIFFERENCES IN ENDOTHELIUM-DEPENDENT RELAXATION IN VARIOUS ARTERIES FROM WATANABE HERITABLE HYPERLIPIDAEMIC RABBITS WITH INCREASING AGE

1. Endothelium-dependent relaxation in response to acetylcholine (ACh) and the calcium ionophore A 23187 was examined in aorta, coronary, basilar and renal arteries isolated from Watanabe heritable hyperlipidaemic (WHHL) rabbits of 2, 6 and 12 months of age, with normolipidaemic heterozygous WHHL rabbits as controls. 2. In the rings of WHHL rabbit aortae and coronary arteries preconstricted with vasoconstrictors, endothelium-dependent relaxation in response to ACh was attenuated with age compared to the heterozygous WHHL rabbits. A significant negative correlation was found between the total cholesterol content and the relaxation response to ACh in the aortae or coronary arteries from 6 and 12 month old WHHL rabbits. 3. In the rings of basilar arteries, endothelium-dependent relaxations to ACh were not modified with age. Similarly, in the rings of renal arteries, the relaxation response to ACh was not changed with age, but in the 6 and 12 month preparations, after the age of 6 months, a contraction following the relaxation appeared at higher concentrations of ACh (10^?7 to 10^?6 mol/L). The contraction was endothelium-dependent and inhibited by indomethacin. 4. A 23187-induced endothelium-dependent relaxations were also markedly attenuated in the aorta and significantly in the coronary artery with age. 5. Endothelium-independent relaxation to sodium nitroprusside was not changed in all arteries from WHHL rabbits of different ages. 6. These findings indicate that in the aorta and coronary artery of the WHHL rabbit, the endothelium-dependent relaxation to ACh and A 23187 becomes impaired with increasing age (i.e., with the progression of cholesterol deposition in the arterial wall) but is preserved in the basilar and renal artery.     

A case of mediastinal neurinoma originating from right intrathoracic vagal nerve

A 34-year-old woman was admitted with an abnormal shadow on a chest X-ray film. Under a preoperative diagnosis of benign bronchogenic cyst, operation was carried out and the tumor was found to be originating from the right main vagal nerve in the mid-superior mediastinum. The vagal nerve was transected to remove the tumor. Pathological diagnosis was a neurinoma. Postoperative complication was chylothorax which was successfully treated with thoracic drainage and intravenous hyperalimentation.     

A case of aneurysm of the inferior left ventricular wall

Aneurysms of the inferior left ventricular wall represent only a small fraction of all aneurysms that have been reported in surgical series. And in comparison to anterior left ventricular aneurysms, a comparatively higher percentage of reported inferior wall aneurysms was classified as false. A 73-year-old male was admitted for acute inferior myocardial infarction. Three weeks after admission, cardiac catheterization was carried out. Coronary arteriography revealed triple vessel disease and left ventriculography showed an aneurysm of the inferior left ventricular wall, whose feature near the mitral annulus was multiple fenestrations. Left ventricular aneurysmectomy and aortocoronary bypass grafting to the left anterior descending artery were simultaneously performed under cardiopulmonary bypass with moderate hypothermia. The pathological feature was a true aneurysm. The postoperative course was uneventful.     

Direct determination of benzalkonium chloride in ophthalmic systems by reversed-phase high-performance liquid chromatography

High-performance liquid chromatography has been used to quantitate benzalkonium chloride (alkylbenzyldimethylammonium chloride) in complex ophthalmic formulations at or below concentration levels of 50 ppm. The method involves a one-step dilution for sample preparation and direct injection; therefore, recovery and/or conversion problems are nonexistent. The assay is quick, specific, reproducible, and simple. This new approach makes routine determinations far simpler than previous methods and is especially useful for product stability studies and quality control procedures.     

Factor VIII lability, protein C and other vitamin K-dependent proteins

The stability of factor VIII was studied in plasmas from patients on long-term warfarin therapy. The percent residual factor VIII activity (F.VIII:C) after incubation at 37 degrees C for 4 hr was higher in warfarinized patients than in normal subjects; 76.9 +/- 10.8% (mean +/- SD) of the initial F.VIII:C in the patients versus 61.6 +/- 5.8% in normal subjects (p less than 0.001). On the whole, neither protein C nor vitamin K-dependent coagulation factors except factor VII activity (F.VII:C) correlated with the residual F.VIII:C. There was a negative and weak correlation between the residual F.VIII:C at 4 hr and either the initial F.VIII:C or F.VII:C. Another experiment using protein C depleted plasma showed a relatively enhanced stability of F.VIII:C in the protein C deficiency. These results indicate that factor VIII is more stable in warfarinized plasma, and that protein C and vitamin K-dependent coagulation factors are not the sole, main factor responsible for such a phenomenon.     

Oxygen-assisted breath-holding in computed tomography

To achieve prolonged breath-holding, oxygen was administered just before dynamic CT and high resolution lung CT. Oxygen administration has proved to be a supportive means to improve the quality of CT studies.