This study was designed to evaluate the contractile and relaxing responses of abdominal aorta in renovascular hypertension accompanied with essential hyper- tension and to examine the effect of angiotensin II receptor blocker(losartan). An experimental renovascular hypertension accompanied with essential hypertension model was established by clipping the left renal artery of spontaneously hypertensive rats(SHR). These rats were then divided into two groups of which one was given losartan during the one week postopertion before being terminated. Ring preparations of the abdominal aorta were obtained one week after the operation. The contraction of abdominal aorta strips were induced by high potassium or norepinephrine, and relaxation produced by acetylcholine or sodium nitroprusside. The contractile and relaxing responses were recorded and compared with data obtained from the control group. In the second experiment, the rats received angiotensin Il blocker(LRAO group), losartan in the drinking water for 7 days after the induction of the renal artery stenosis operation. Then, the contractile and relaxing responses were evaluated by the same method. The following results were obtained; 1) The contractile responses to the high level potassium solution and norepinephrine in renal artery occlusion(RAO) group were significantly increased compared with SHR group(p<0.05). 2) The contractile reponses to the high level norepinephrine in LRAO group were similar to that of SHR control group. However, there was no remarkable differences for high potassium. 3) The relaxing responses to the acetylcholine were significantly reduced in the RAO group compared with the SHR group. However, there was no remarkable differences for sodium nitroprusside. 4) There were no significant differences in the acetylcholine or sodium nitroprusside induced vasodilation response between the LRAO group and SHR group. From the above result, it is suggested that re- novascular hypertension in spontaneously hypertensive rats might induce changes of vascular responses and this effects may be concerned with endothelium-dependant mechanism. And angiotensin II receptor blocker rnay prevent the development of abnormal endothelium-dependent relaxation in renovascular hypertension accompanied with essential hypertension by maintaining endothelial function.
Acetylcholine ; Angiotensin II* ; Angiotensins* ; Animals ; Aorta, Abdominal* ; Drinking Water ; Hypertension ; Hypertension, Renovascular* ; Losartan ; Nitroprusside ; Norepinephrine ; Potassium ; Rats ; Rats, Inbred SHR* ; Receptors, Angiotensin ; Relaxation ; Renal Artery ; Renal Artery Obstruction ; Vasodilation

The number of patients and long-term survival rates of chronic renal failure have been increasing since the development of renal replacement therapy. Therefore, continuous follow-up observation on an outpatient basis, vascular access for dialysis and the determination of when to start dialysis have clinical significance associated with the prognosis of these patients. Presently, there is little clinical data about chronic renal failure patients such as, clinical features at initial dialysis, the presence or absence of neph-rologist follow-up, and the types and timing of vas-cular access. The goal of this study therefore was to investigate the clinical features at initial dialysis, presence or absence of follow-up, types and timing of vascular access in 80 patients retrospectively. The results are as below ; 1) The mean age of the patients was 47.8+/-14.0 years, and there were 47 male and 33 female patients. 2) Seventeen patients(21.3%) had DM as an underlying disease and 63 patients(78.79%) were non-diabetic patients. 3) At the initial dialysis, the diabetic patients had an average BUN of 79.2 +/- 29.6mg/dl, average Cr of 7.82.0mg/dl and an average Ccr of 10.0+/-7.0ml/min. The non-diabetic patients had the following averages ' BUN 118.7 +/- 37.9mg/dl, Cr 15.36.3mg/dl and Ccr 5.5 +/- 4.3ml/min. 4) The initial meeting with a nephrologist prior to dialysis occured as follows : in the diabetic group, 13 patients(76.596) met their nephrologist 12 months before, 3 patients(17.6%) 1 month before, one patient(5.9N) met the specialist one to 3 months before and no one had meeting 4 to 12 month before their dialysis. In the non-diabetic group, 36 patients(63.296) initially visited a nephrologist 12 months before, 16 patients (28.1M) one month before, 3 patients(5.3%) one to 3 months before and 2 patients(3.5%) had a meeting 4 to 12 months before the first dialysis. 5) The timing of native arteriovenous fistula for- mation was as follows; In the diabetic group, 10 patients(66.7%) had an A-V fistula constructed imme- diately upon admission, 2 patients(13.3%) had one constructed one to 3 months before, 2 patients(13.396) had one made 4 to 12 months before, one patient (6.7%) had a fistula created one week to one month before, and no one had a fistula formed 12 months before their initial dialysis. In the non-diabetic group, 36 patients(69.2%) had an A-V fistula constructed on admission ll patients(21.2%), one week to one month before 2 patients(3.8%), one to 3 rnonths before 2 patients(3.8%), 4 to 12 months before - one patient(1.9%) had the fistula created 12 months before initial dialysis. From these results, we learned that the time interval between either the patient's first meeting with his/her nephrologist or initial referral for renal replacement and vascular access preparation for hemodialysis was much longer than what is currently known. In conclusion, prompt referral to a nephro-logist early in the course of the disease and proper education of the patient by the nephrologist can lead to timely initiation of dialysis at a lower serum creatinine and higher Ccr levels which will reduce mortality, morbidity, and hospital care cost.
Arteriovenous Fistula* ; Creatinine ; Dialysis ; Education ; Female ; Fistula ; Follow-Up Studies ; Humans ; Kidney Failure, Chronic ; Male ; Mortality ; Outpatients ; Prognosis ; Referral and Consultation ; Renal Dialysis* ; Renal Replacement Therapy ; Retrospective Studies ; Specialization ; Survival Rate