We evaluated the effects of long-term treatment with benidipine, a long-acting calcium antagonist, on endothelial cell-type nitric oxide synthase (eNOS) activity and eNOS mRNA expression in the left ventricle (LV) and its relation to coronary flow reserve, and microvascular remodeling in renovascular hypertensive rats (RHR: 2K-1C Goldblatt). Benidipine (5 mg/kg/day) was given to RHR (B-RHR, n = 11) for 6 weeks. Vehicle-treated RHR (U-RHR, n = 11) and age-matched sham-operated rats (ShC, n = 11) served as control group. Coronary flow reserve was measured in conscious rats using colored microspheres. Fifty-micrometer slices of the LV were incubated with L-arginine to measure nitrite production using the Griess method and eNOS mRNA expression was determined by reverse transcription-polymerase chain reaction. An increased blood pressure in RHR was significantly decreased by benidipine. Nitrite production and eNOS mRNA expression in the LV of U-RHR was significantly lower than that of ShC. This suppression of nitrite production and eNOS mRNA expression was significantly reversed in B-RHR. U-RHR demonstrated a significant decrease in coronary flow reserve and capillary density, and a significant increase in wall-to-lumen ratio, perivascular fibrosis, myocardial fibrosis, and myocyte cross-sectional area. These impaired factors were improved significantly by benidipine. These findings suggest that benidipine therapy may increase nitrite production and eNOS mRNA expression not only by lessening the endothelial damage by the reduction of blood pressure levels, but also by the stimulation of NOS activity and eNOS mRNA, and this increased NOS activity and eNOS mRNA expression may play a role in the amelioration of coronary flow reserve and microvascular remodeling.

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Since its experimental introduction in 1960, hemodialysis has become a widely performed and relatively safe procedure. Therapeutic strategies have been developed, and the numbers of long-term survivors of hemodialysis therapy have been increasing. Hemodialysis therapy was introduced at Sangenjaya Hospital in October 1970, and the 16 patients who have survived for more than 30 years on hemodialysis therapy since its introduction at the hospital were enrolled in this study to investigate the characteristics of long-term hemodialysis patients. For comparison, 50 patients on hemodialysis for less than 30 years were also studied (21 patients with <10 years hemodialysis, 13 with 10-20 years hemodialysis and 16 with 20-30 years hemodialysis). Background information (age, gender, and cause of renal disease), dialysis dose (single pool [sp.] Kt/V), mineral metabolism (serum phosphate), anemia management (serum hemoglobin), and nutrition (serum albumin and reduced interdialytic weight gain) were assessed. Hemodialysis was instituted at 28.7 +/- 6.4 years of age. The primary cause of end-stage renal disease was chronic glomerulonephritis in all of the patients except one, and in that patient it was polycystic kidney disease. As an index of the dialysis dose, sp. Kt/V was 1.2 +/- 0.11. As an index of mineral metabolism, serum phosphate was 5.4 +/- 0.9 mg/dL. As an index of anemia management, serum hemoglobin was 10.2 +/- 1.2 g/dL. As indexes of nutrition, serum albumin was 4.0 +/- 0.2 g/dL and interdialytic weight gain was 4.43 +/- 1.36%. The sp. Kt/V-value, serum phosphate, serum hemoglobin and interdialytic weight gain did not differ between the four different hemodialysis duration groups. Serum albumin was lower in the >30 group (4.0 +/- 0.2 g/dL) than in the <10 group (4.2 +/- 0.3 g/dL) (P = 0.046). As the duration of hemodialysis has increased, the age at hemodialysis induction has become younger. The cause of the renal failure was chronic glomerulonephritis in most of the cases. None had diabetic nephropathy. Improvement of the prognosis of patients with diabetic nephropathy is required. Most of the indexes of these patients nearly satisfied the recommended values.

The hemodynamic effects of various numbers of colored nonradioactive microspheres (CMS) and those of accumulation of CMS caused by multiple sequential injection were evaluated in 51 Sprague-Dawley male rats. CMS (15 microns) were injected into the left atrium. Regional blood flow and cardiac output were evaluated using the reference blood sample technique. Ficoll-70 was given after each blood sample withdrawal as a fluid replacement. A bolus injection of < or = 1,000,000 CMS caused no significant hemodynamic disturbances. Amounts of 500,000 CMS can be repeatedly injected up to four times (cumulative dose of 2,000,000 CMS) without producing any adverse hemodynamic effects. The values of cardiac output obtained with the CMS technique were correlated well (r = 0.971, P < 0.0001) with those obtained with electromagnetic flow probes. An excellent reproducibility of organ blood flow was observed after four sequential injections of 500,000 CMS. This study establishes the limits of CMS that can be injected into the rat without inducing hemodynamic changes and also suggests that the CMS technique can be employed to evaluate cardiac output and regional blood flow precisely and repeatedly.

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Evidence has been provided that the immunological mechanism is involved in the genesis or maintenance of hypertension. In the present study, we investigated the effects of interferon gamma, a potent immunomodulator derived from lymphocytes, on hypertension and organ damage in Dahl salt-sensitive rats and in spontaneously hypertensive rats. Subcutaneous injection of interferon gamma (SxlO 4 units/kg body wt once a week for 10 weeks) reduced blood pressure in Dahl salt-sensitive rats fed a 4% high salt diet (174 versus 194 mm Hg, p<0.025). This blood pressure reduction was associated with an improvement of renal functions, an increase in glomerular nitration rate (690 versus 569 ml/day/100 g body wt, p<0.05), and decreases in urinary protein excretion (48 versus 78 mg/day/100 g body wt, p< 0.025) and urinary N-acetyl-/3-D-glucosaminidase excretion (143 versus 183 milliunits/day/100 g body wt, p<0.05). Morphological investigation showed a marked resolution of the vascular injuries seen in untreated Dahl salt-sensitive rats, e.g., intimal and medial hyperplasia, with infiltration of inflammatory cells, and significant amelioration of the glomerular sclerotic changes. In contrast, interferon gamma affected neither blood pressure nor renal functions in spontaneously hypertensive rats. These data indicate that interferon gamma ameliorates the development of hypertension and vascular and renal injuries in Dahl salt-sensitive rats. The resolution of vascular and renal injuries contributes, in part, to the antihypertensive action of interferon gamma. there is an association between hypertension and immune dysfunction in humans and in experimental hypertensive animals.1 -2 The mechanism of this interrelation is not fully understood. However, since White and Grollman 3 reported the implications of autoimmunity in hypertension after renal infarct, an increasing amount of evidence has indicated that suppressor T cell dysfunctions and subsequent hyperimmunoglobulinemia or an increase in autoantibodies would bring about the vascular injuries and renal damage of a hypertensive state, both of which are supposed to contribute to the development of hypertension, particularly in its chronic phase. 4 -6 It has been demonstrated, in fact, that the periarterial spaces are infiltrated with inflammatory cells in spontaneously hypertensive rats (SHRs), and these lesions are resolved by immunosuppressive therapy.7 Moreover, the arterial damages in salt-induced hypertension could not be produced in nude mice.