Genistein potentiates the relaxation induced by beta1- and beta2-adrenoceptor activation in rat aortic rings

In rat aortic rings, genistein, an inhibitor of tyrosine kinase, but not daidzein, an inactive analogue of genistein, potentiated the relaxation induced by isoproterenol. Atenolol, a beta1-adrenoceptor antagonist, or ICI-118,551, a beta2-adrenoceptor antagonist, inhibited the relaxation induced by isoproterenol. The potentiating effect of genistein on the relaxation induced by isoproterenol in the presence of ICI-118,551 was apparently greater than that in the presence of atenolol. In the presence of ICI-118,551, theophylline, an inhibitor of cyclic adenosine monophosphate (cAMP)-dependent phosphodiesterase (cAMP-PDE), markedly inhibited the potentiating effect of genistein on the isoproterenol-induced relaxation, whereas in the presence of atenolol, theophylline only partly inhibited the potentiating effect of genistein. The relaxation induced by forskolin, an activator of adenylyl cyclase, was potentiated by genistein or theophylline. In the presence of theophylline, the relaxation induced by forskolin was not further affected by genistein. Genistein also inhibited the activities of cAMP-PDE. In the presence of atenolol, but not ICI-118,551, iberiotoxin, an inhibitor of Ca-activated K channels, inhibited the relaxation induced by isoproterenol and the potentiating effect of genistein. In the presence of atenolol, quinacrine, an inhibitor of phospholipase A2, and metyrapone, an inhibitor of P-450 enzymes, but not alpha-naphthoflavone, an inhibitor of P-450 enzymes, indomethacin, a cyclooxygenase inhibitor, or AA861, a 5-lipoxygenase inhibitor, inhibited the potentiating effect of genistein. These results suggest that the potentiation of the beta1-adrenoceptor-induced relaxation by activation of genistein may mostly be due to inhibition of cAMP-PDE activities. In addition, the potentiation of the relaxation induced by activation of beta2-adrenoceptors by genistein may be related to the inhibition of arachidonic acid metabolism and cAMP-PDE activities.

Relationship of renal histological damage to glomerular hypertension in patients with immunoglobulin A nephropathy

OBJECTIVE

Studies of experimental animals show glomerular hypertension to be important in the progression of glomerular disease. We evaluated this connection clinically by examining the relationship between glomerular hemodynamics and histological changes in patients with immunoglobulin (Ig)A nephropathy.

METHODS

The subjects were 23 patients with IgA nephropathy. All patients underwent renal biopsies. Glomerular hemodynamics, in terms of glomerular capillary hydraulic pressure (PGC) and the whole-kidney ultrafiltration coefficient, were calculated from the renal clearance, plasma total protein concentration, and pressure-natriuresis relationship. The severity of glomerulosclerosis, tubulointerstitial damage and mesangial matrix expansion was evaluated semiquantitatively.

RESULTS

PGC ranged from 33-69 mm Hg, and the mean arterial pressure (MAP) from 79-112 mm Hg. Their correlation was not significant (r= 0.29, P= 0.18). PGC was significantly correlated with the glomerulosclerosis score, and also with the score for tubulointerstitial damage (r= 0.65, P < 0.001 and rs = 0.59, P = 0.007, respectively), but not with the score for mesangial matrix expansion (r= 0.08, P= 0.72). MAP was significantly correlated only with the score for tubulointerstitial damage (rs = 0.63, P = 0.004). In multiple linear regression analysis of the histological changes and hemodynamics, the glomerulosclerosis score and the score for tubulointerstitial damage were correlated with PGC, but not with MAP.

CONCLUSION

These clinical results support the speculation that glomerular hypertension is involved in the glomerulosclerosis and tubulointerstitial damage that occurs in IgA nephropathy.

A new technique for implanting a fine-wire microelectrode for chronic recording of unit activity from freely-moving mice

We report here a newly developed chronic implantation technique using an epoxy-coated fine-stainless steel wire (33 microm in diameter) to record single unit activity from the brain of freely-moving mice with as little tissue injury as possible. Since the fine-wire electrode is not capable of staying straight by itself or of penetrating into the brain, a pair of permanent neodymium magnets placed on a micromanipulator as well as below the animal's head was used for stereotaxic implantation to keep the fine-wire straight and strong by the magnetic fields. With those implanted electrodes recording of single units from the hippocampal CA1 of freely-moving mice was performed during sleep and wakefulness.

Creatinine clearance as a substitute for the glomerular filtration rate in the assessment of glomerular hemodynamics

A method for the clinical assessment of glomerular hemodynamics has been published previously. We here examined whether, when using this method, renal creatinine clearance (Ccr) can be substituted for the glomerular filtration rate (GFR). The study subjects comprised 57 inpatients from Osaka City General Hospital: 30 with type 2 diabetes mellitus and 27 with chronic glomerulonephritis. During the 2-wk study, patients received a high-salt diet for 1 wk and a low-salt diet for 1 wk. Urinary sodium excretion and systemic blood pressure were measured daily. The renal plasma flow, Ccr, and plasma total protein concentration were also evaluated simultaneously on the last day of the high-salt diet. The GFR was also calculated from the fractional renal accumulation of 99mTc-diethylenetriaminepentaacetic acid (DTPA). Glomerular hemodynamics, represented by the glomerular capillary hydraulic pressure and the resistance of afferent and efferent arterioles, were calculated using the renal clearance, the plasma total protein concentration, and the pressure-natriuresis relationship. Values for renal hemodynamics with the Ccr-derived GFR were compared with those from the 99mTc-DTPA-derived GFR. Ccr values of 53 to 169 ml/min correlated with the 99mTc-DTPA-derived clearance of 39 to 179 ml/min (n=57, r=.71, p<.001). Values for the glomerular pressure and the resistances of afferent and efferent arterioles calculated using the Ccr-derived GFR correlated significantly with those calculated using the 99mTc-DTPA-derived GFR (r=.99, p<.001 and r=.99, p<.001, respectively). These results indicate that the Ccr is an accurate representation of the GFR for use in glomerular hemodynamic analysis of the pressure-natriuresis relationship.

Glomerular hypertension as one cause of albuminuria in type II diabetic patients

AIMS/HYPOTHESIS

Results from animal models of glomerular hypertension have suggested that this disorder is one cause of albuminuria in diabetic nephropathy. We evaluated this hypothesis clinically.

METHODS

The subjects were 20 patients with Type II (non-insulin-dependent) diabetes mellitus but without uraemia or hypertension: 8 had normoalbuminuria and 12 had albuminuria (> or = 20 micrograms/min). In the 2-week study, patients were on a diet with ordinary amounts of sodium for 1 week and on a sodium-restricted diet for 1 week. Urinary excretion of sodium and albumin and the systemic blood pressure were measured daily. Intrarenal haemodynamics, in terms of the glomerular pressure and resistance of afferent and efferent arterioles, were calculated from renal clearance, the plasma total protein concentration, and the pressure-natriuresis relation. In 8 of the 12 patients with albuminuria, an angiotensin-converting enzyme inhibitor, cilazapril, was given orally (2 mg/day) and the 2-week study was repeated.

RESULTS

In patients with albuminuria, resistance of efferent arterioles and the glomerular pressure were higher than in patients with normoalbuminuria (glomerular pressure, 53 +/- 5 vs 43 +/- 5 mmHg, means +/- SD, p < 0.001). Urinary excretion of albumin correlated (n = 20, r = 0.675, p < 0.001) with the glomerular pressure but not with systemic pressure. The increased glomerular pressure and the albuminuria were decreased by cilazapril but systemic pressure was not.

CONCLUSIONS/INTERPRETATION

These findings are consistent with the hypothesis that glomerular hypertension is present in Type II diabetic patients with early nephropathy and can cause albuminuria.

Increased nitroglycerin-induced relaxation by genistein in rat aortic rings

The effect of genistein, a tyrosine kinase inhibitor, on nitroglycerin-induced relaxation was examined in rat aortic rings contracted by phenylephrine. In rat aortic rings, genistein (10(-5) M and 3x10(-5) M), a tyrosine kinase inhibitor, but not daidzein, an analogue of genistein, increased relaxation induced by nitroglycerin in a concentration-dependent manner. Iberiotoxin, an inhibitor of Ca2+ -activated K+ channels, inhibited the relaxation induced by nitroglycerin, but it did not affect the effect of genistein. Glibenclamide, an inhibitor of ATP-sensitive K+ channels, did not affect the relaxation induced by nitroglycerin. Theophylline, an inhibitor of cyclic AMP-dependent phosphodiesterase, increased the relaxation induced by nitroglycerin, and genistein (10(-5) M) failed to affect the relaxation induced by nitroglycerin in the presence of theophylline. Genistein also inhibited the activity of cyclic AMP-dependent phosphodiesterase. In addition, 6-[4-(4'-pyridyl)amino phenyl]-4,5-dihydro-3(2H)-pyridazinone hydrochloride, an inhibitor of cyclic GMP-inhibitable cyclic AMP phosphodiesterase, inhibited the relaxation induced by nitroglycerin. These results suggest that, in the rat aortic rings, genistein inhibits cyclic AMP-dependent phosphodiesterase activities, resulting in the increase of the relaxation induced by nitroglycerin.

Posttraumatic intestinal stenosis presenting as a perforation: report of a case

A 78-year-old woman was admitted to the hospital after falling into a ditch approximately 1 m deep and sustaining a blunt abdominal trauma with a left femur fracture. On the tenth day after admission, symptoms of a small bowel obstruction occurred. A nasogastric tube was inserted, and the symptoms thus improved. She sometimes complained of abdominal pain during the 12 months after the fall, but recovered with conservative management. The next year, she was readmitted to the hospital for a pin extraction of the left femur bone. During this admission, 15 months since her admission after her fall, she again complained of abdominal pain. Abdominal pain increased with a muscular defense, and abdominal X-rays revealed free air. She was referred to our hospital with a diagnosis of perforative peritonitis, and emergency surgery was performed. Upon laparotomy, circumferential stenoses of the small bowel were recognized in the proximal segments about 40cm, 80cm, and 100cm from the ileocecal region. In addition, a perforation and prominent dilatation of the bowel segment was observed just proximal to the stenosis about 100cm from the ileocecal region. She underwent a small intestinal resection at two sites. There were no findings of an intestinal specific ulcer, such as Crohn's disease, intestinal tuberculosis, or malignancy, based on the results of a histopathological examination.

[Thoraco-abdominal impalement injury with diaphragmatic injury: a case report]

A 60-year-old man was admitted to our hospital because of impalement injury due to traffic accident. Chest X-ray on admission revealed normal lung field. CT scans of the chest and abdomen revealed slight pneumothorax and intra-abdominal organ protruding from abdominal cavity. An emergency operation was performed. Diaphragmatic injury was not detected during the abdominal procedure. On exploring the back wound, we found a laceration of 8 cm in diameter in the diaphragm and repaired it. Impalement injuries which have aspects of both blunt and penetrating trauma are uncommon. Accordingly, wound exploration and debridement of fistulous tract are necessary. In the case of thoraco-abdominal injuries by impalement, one should bear in mind the existence of diaphragmatic injury even with normal diaphragmatic shadow on chest X-ray.

Evaluation of rat sperm by flow cytometry: simultaneous analysis of sperm count and sperm viability

In this study, we conducted a simultaneous analysis of sperm count and viability in rats by flow cytometry (FCM). Epididymal fluids were taken from the caudal epididymis of 12 to 13 week-old Sprague-Dawley rats. The fluids were weighed and mixed with Dulbecco's phosphate buffered saline (D-PBS). Propidium iodide, which can stain only dead sperm, was used to distinguish viable and dead sperm. The sperm count and viability analyzed by FCM were 1.28 x 10(6)/mg and 78.0%, respectively. These values were consistent with the corresponding values (1.39 x 10(6)/mg and 81.0%) that were directly determined microscopically in the fluids of the same sample. In addition, when the original mixture containing sperm was diluted two times and four times with D-PBS, or was diluted two times with D-PBS containing only killed sperm, the sperm count and viability determined by FCM also correlated well with the sperm count (r = 0.96, P < 0.01) and sperm motility (r = 0.99, P < 0.01) by direct microscopic observation, respectively. In conclusion, the present flow cytometric analysis would be practical for the simultaneous determination of sperm count and viability in rat epididymal fluids.

Post-transplant diabetes with anti-glutamic acid decarboxylase antibody during tacrolimus therapy

A 54-year-old man undergoing hemodialysis because of end-stage renal failure was transplanted with a cadaver kidney in November 1997. He had no history of diabetes. Tacrolimus was used as the primary immunosuppressant. Three weeks after transplantation, he developed insulin-requiring diabetes mellitus. Anti-glutamic acid decarboxylase antibody was not detected on the third post-operative day, but appeared 4 weeks after transplantation. The recipient had DNA haplotypes that indicated susceptibility to Type 1 diabetes in Japanese subjects. Immunosuppressive therapy was changed from tacrolimus to cyclosporin. Thereafter, titer of anti-glutamic acid decarboxylase antibody disappeared and the patient's insulin requirement was notably reduced. The mechanism underlying the development of diabetes in this case appears to be, in part, direct beta-cell toxicity due to tacrolimus therapy, resulting in secondary beta-cell autoimmunity. This case suggests that tacrolimus therapy after transplantation should be used with caution in patients with genetic susceptibility to Type 1 diabetes.

[Application of a semi-automatic ROI setting system for brain PET images to animal PET studies]

ProASSIST, a semi-automatic ROI (region of interest) setting system for human brain PET images, has been modified for use with the canine brain, and the performance of the obtained system was evaluated by comparing the operational simplicity for ROI setting and the consistency of ROI values obtained with those by a conventional manual procedure. Namely, we created segment maps for the canine brain by making reference to the coronal section atlas of the canine brain by Lim et al., and incorporated them into the ProASSIST system. For the performance test, CBF (cerebral blood flow) and CMRglc (cerebral metabolic rate in glucose) images in dogs with or without focal cerebral ischemia were used. In ProASSIST, brain contours were defined semiautomatically. In the ROI analysis of the test image, manual modification of the contour was necessary in half cases examined (8/16). However, the operation was rather simple so that the operation time per one brain section was significantly shorter than that in the manual operation. The ROI values determined by the system were comparable with those by the manual procedure, confirming the applicability of the system to these animal studies. The use of the system like the present one would also merit the more objective data acquisition for the quantitative ROI analysis, because no manual procedure except for some specifications of the anatomical features is required for ROI setting.

[Myxoid liposarcoma surrounding non-functioning transplanted kidney after living renal transplantation: a case report]

A 19-year-old male visited our clinic with the complaint of lower abdominal distention, January 1992. He had undergone living renal transplantation from his mother as a donor on June 15, 1988. But the transplanted kidney had become functional loss by chronic rejection 3 years after transplantation. The computed tomography showed huge low density mass around the non-functioning transplanted kidney. En block resection of the tumor and the transplanted kidney was performed. The tumor was pathologically diagnosed as mixoid liposarcoma. It was proved that the tumor cells were derived from recipient cells by the investigation of HLA-DRB1 DNA typing.

Artificial nine zinc-finger peptide with 30 base pair binding sites

It is well-known that DNA binding of native nine zinc-finger protein TEIIIA is dominated by interaction of select few fingers. Newly designed zinc-finger peptide Sp1ZF9 containing nine Cys2-His2 type motifs has been manipulated. The DNA-binding property of Sp1ZF9 was compared with those of native three zinc-finger Sp1(530-623) and artificial six zinc-finger Sp1ZF6 peptides. Although the equilibrium time was less than 0.5 h for Sp1(530-623)-DNA complex, Sp1ZF6 and Sp1ZF9 required approximately 48 and 72 h, respectively, for full complex formation. Evidently, the footprinting analysis demonstrated that Sp1ZF9 and Sp1ZF6 bind at least 27 and 18 contiguous base pairs of DNA sequence, respectively. Sp1ZF9 showed two step bindings to DNA, namely first the recognition of GC (5'-GGG-GCG-GGGCC-3') sequence by the N-terminal Sp1 domain and next the recognition of the corresponding target sequences by the middle and C-terminal Sp1 domains. In contrast with unimolecular binding of Sp1ZF9 and Sp1ZF6, two Sp1(530-623) molecules bind to one GCIII (5'-GGG-GCG-GGG-GGG-GCG-GGG-GGG++ +-GCG-GGGCC-3') site region. Semispecific complex formed at the beginning of Sp1ZF9-DNA interaction has also been characterized by kinetic analysis using surface plasmon resonance. Interestingly, the association rate constants for GC and GCIII complexes of Sp1ZF9 are smaller than those of the corresponding Sp1(530-623) complexes. Of special interest is the fact that new nine zinc-finger peptide Sp1ZF9 can bind to DNA sequence of approximately 30 base pairs. Such multi zinc-finger peptides may be useful as genome-specific transcriptional switches in future.

[Postoperative complications after Mainz pouch construction--with emphasis on measures to deal with narrowing of the duct aperture]

Thirty patients underwent Mainz pouch construction between December 1992 and January 1998. The post-operative observation period varied from 6 to 57 months (average, 38.5 months). A mechanism to ensure urinary continence was provided in 24 cases, while formation of a nipple valve by intussusception of the ileum with seromuscular stripping and submucosally embedded in situ appendix was performed in 6 cases. An umbilical stoma was adopted in all cases. Late-phase complications included 3 cases of hydronephrosis requiring treatment. Efferent limb of the stoma was observed in 8 cases, 6 of which were attributable to mild constriction of the stoma at the site of anastomosis of the navel cavity. In those cases in which stomal stricture occurred, difficulty in withdrawing urine was eliminated by providing a fistula stopper. Although few clinical methods to deal with stomal stricture have been reported, we found the fistula stopper to be useful providing good external appearance and patients' quality of life.

Aspirin renography in diagnosis of unilateral renovascular hypertension

We previously proposed that aspirin can enhance the diagnostic sensitivity of renography with [123I] orthoiodohippurate (OIH) in patients with suspected unilateral renovascular hypertension (RVH). In this study we assessed the sensitivity and specificity of this method. Twenty-four patients, 14 with unilateral RVH and 10 with essential hypertension, were studied. For all patients with RVH, definitive diagnosis was based on the results of angiography and the response to renal arterial angioplasty after this study. For all patients with essential hypertension, we confirmed that there was little if any stenosis of the renal artery by digital subtraction angiography or Doppler sonography. Renography with [123I]OIH or 99mTc-mercaptoacetyltriglycine (MAG3) was done once before and once after the oral administration of aspirin (20 mg/kg). We considered renal blood flow to be decreased if the time to the peak in renography was 5 min or more, and defined the peak times of the kidneys as different if separated by 2 min or more. Unilateral RVH was diagnosed when both criteria were met. Renography before aspirin administration indicated RVH in 7 of the 14 patients with RVH, and renography after aspirin indicated RVH in 13 of the 14 patients. Of the 10 patients with essential hypertension, renography before and after aspirin administration showed no difference between the kidneys in 8 patients. Thus, aspirin renography increased the sensitivity from 50% to 93%, but did not change the specificity (80%) in the diagnosis of RVH. These results suggest that renography with [123I]OIH or 99mTc-MAG3 for the diagnosis of unilateral RVH is more sensitive when aspirin is used.

A modified microsyringe for extracellular recording of neuronal activity

We describe a modified Hamilton microsyringe that allows extracellular recording of neuronal activity and subsequent injections. It is assembled with a Hamilton removable needle and a syringe for injection, a Teflon-coated tungsten wire for recording, and polyimide tubing as a sheath. The device is inexpensive and easy to handle in anatomical and physiological experiments in awake monkeys.

New multi zinc finger protein: biosynthetic design and characteristics of DNA recognition

New six zinc finger protein DSp1 was created by connecting two Sp1 DNA binding domains. The DNA recognition characteristics of DSp1 demonstrate that (1) this multi finger protein binds eighteen contiguous base pairs of DNA sequence, (2) each zinc finger wraps around DNA major groove, and (3) two Sp1 domains have nonequivalent contribution to the DNA binding of DSp1.

[Is tacrolimus effective for ongoing renal allograft rejection?]

Tacrolimus has already gained a high reputation as an induction-maintenance immunosuppressive therapy after kidney transplantation. Recently, it is being used as rescue therapy against rejection, and its effectiveness also appears to have been established to some extent. In this study, we evaluated the efficacy of Tacrolimus rescue therapy at 4 institutions in the Kinki District. The subjects were 19 patients treated with Tacrolimus against rejection observed during immunosuppressive therapy using cyclosporin. Evaluation was made by classifying the patients into 6 with acute rejection that occurred within 3 months after transplantation (AR), 4 with late onset acute rejection that developed more than 3 months after operation (LAR), and 9 patients with chronic rejection (CR). In the AR group, many patients received combination therapy at the introduction of Tacrolimus, and the long-term outcome was satisfactory. Tacrolimus was effective in 2 (50%) of the 4 patients in the LAR group. The trough levels of Tacrolimus at its introduction were 10-15 ng/ml in the AR and LAR groups. Deterioration of the transplanted kidney function was prevented in 3 (50%) out of 6 patients in the CR group observed for less than 1 year, but it deteriorated in all 3 patients observed for 1 year or longer. The trough levels of tacrolimus at its introduction were 5-10 ng/ml in many patients in the CR group. The rescue therapy using Tacrolimus was effective against acute rejection but further follow-up is considered to be needed to evaluate its efficacy against chronic rejection.

Glomerular charge and size selectivity assessed by changes in salt intake in type 2 diabetic patients

OBJECTIVE

To evaluate glomerular charge selectivity in patients with type 2 diabetes, we studied changes in fractional clearance of proteins with different sizes and charges when patients were placed on two diets with different salt contents.

RESEARCH DESIGN AND METHODS

Nineteen patients with type 2 diabetes and normoalbuminuria (< 20 micrograms/min, n = 8), microalbuminuria (20-100 micrograms/min, n = 7), or advanced albuminuria (> 100 micrograms/min, n = 4) were placed on a low-salt diet (85 mEq of sodium daily) or a high-salt diet (255 mEq of sodium daily) for 1 week, and then on the other diet, in random order. Fractional clearances of albumin and immunoglobulin G (IgG) were calculated on the last 3 days of each diet.

RESULTS

In patients with normoalbuminuria, the high-salt diet increased the fractional clearance of IgG, which is electrically neutral, but the fractional clearance of albumin, which is anionic, was unaltered, suggesting that the pore charge of the glomerular barrier was unaffected. However, in patients with microalbuminuria, the high-salt diet increased the fractional clearances of IgG and albumin equally, indicating some neutralization of the pore charge. Fractional clearance of IgG in these first two groups was similar when salt intake was low, so pore size was the same in these groups. In patients with advanced albuminuria, fractional clearance of IgG was higher than in the other groups, indicating that size selectivity had worsened.

CONCLUSIONS

In type 2 diabetic patients, charge selectivity is lost before size selectivity as diabetic nephropathy progresses.

Intracranial gas on CT after cardiopulmonary resuscitation: 4 cases

We report four patients in whom gas was seen in the head on CT shortly after cardiopulmonary resuscitation. The gas was in the posterior cranial fossa, presumably within veins, or in the cavernous sinus. The cause of the cardiac arrest was myocardial infarction in three patients and hanging in one. All had peripheral or central venous lines. The mechanism by which gas appeared in the intracranial veins is discussed.

Mechanism of decreased albuminuria caused by angiotensin converting enzyme inhibitor in early diabetic nephropathy

The mechanism of decreased albuminuria caused by an inhibitor of angiotensin converting enzyme (ACE) was investigated in patients with early diabetic nephropathy. The subjects were 10 patients with non-insulin-dependent diabetes mellitus without azotemia but with albuminuria (less than 650 mg/day). First, a two-week study was done: one week with a diet with ordinary sodium levels and one week with a sodium-restricted diet, in random order. The systemic blood pressure and urinary excretion of sodium and albumin were measured daily. Intrarenal hemodynamics, in terms of the resistance of afferent and efferent arterioles (RA and RE) and glomerular capillary pressure (PGC), were calculated from renal clearance, the plasma total protein concentration, and the pressure-natriuresis relationship. Results obtained before and two weeks after starting the ACE inhibitor cilazapril (2 mg/day) were compared. Urinary excretion of albumin was decreased by cilazapril in 8 of the 10 patients. Cilazapril decreased the RE [6830 (3680, 14,750) to 4660 (1750, 10,790) dynes.sec.cm-5, P < 0.05, mean (minimum, maximum)] and PGC (53 +/- 5 to 43 +/- 9 mm Hg, P < 0.02, mean +/- SD) in these 8 patients, but not in the two other patients. The RA was not significantly changed in any patient. The percent change caused by cilazapril in the urinary excretion of albumin was significantly correlated with the change in PGC (N = 10, r = 0.875, P < 0.01), but not with changes in the systemic blood pressure. In conclusion, the mechanism by which an ACE inhibitor caused a short-term decrease in albuminuria in early diabetic nephropathy involved a glomerular hemodynamic change, namely, a decrease in PGC.

Effects of cicletanine on prostaglandin I2 and E2 levels in patients with essential hypertension

Cicletanine is a new antihypertensive drug that seems to stimulate the synthesis of prostaglandin (PG) I2. However, there is little evidence that cicletanine increases the level of PGI2 in the systemic blood of human subjects long-term. To investigate the antihypertensive mechanism of cicletanine, we measured serially the systemic blood pressure and the levels of both 6-keto-PGF1alpha (a stable metabolite of PGI2) and PGE2 in plasma and urine after administration of cicletanine. Nine patients with essential hypertension on a diet with sodium intake of 120 mEq/day took 100 mg of the drug orally daily every day for 1 week. Systemic blood pressure was measured hourly for 24 h on day 7 of the control period and on days 1 and 7 of the cicletanine period. The two PGs of interest were extracted, purified by high pressure liquid chromatography, and measured by radioimmunoassay. Cicletanine decreased blood pressure without reflexial tachycardia. The plasma levels of 6-keto-PGF1alpha were slightly, but significantly, higher at 3 h after the administration of cicletanine on both days 1 and 7 of administration (on day 1, 3.88 +/- 1.44 pg/mL and on day 7, 4.07 +/- 0.76, means +/- SD, both P < .05 v before administration on day 1) than before administration on day 1 (3.21 +/- 1.25 pg/mL). Plasma PGE2 was higher before and at 3 h after administration on day 7 than at 12 noon on day 7 of the control period. Cicletanine increased the urinary excretion of the two PGs; the increased PG levels partly account for the increased natriuresis in the first 3 days. The antihypertensive effects of cicletanine taken for 1 week were based on natriuresis caused by increased systemic synthesis of the vasodilator PGI2 and partly by the increased renal synthesis of PGI2 and PGE2.