A vasodilating ß1 blocker celiprolol inhibits muscular release of uric acid precursor in patients with essential hypertension.

Although nonvasodilating ß1 blockers increase the levels of uric acid in serum, it is not known whether vasodilating ß1 blockers have a similar effect. In the present study, we evaluated the effect of celiprolol on the release of hypoxanthine, a uric acid precursor, from muscles after an exercise. We used the semi-ischemic forearm test to examine the release of lactate (ΔLAC), ammonia (ΔAmm), and hypoxanthine (ΔHX) before and 4, 10, and 60 min after an exercise in 18 hypertensive patients as well as 4 normotensive subjects. Before celiprolol treatment, all the levels of ΔHX and ΔAmm, and ΔLAC were increased by semi-ischemic exercise in hypertensive patients, and the increases were remarkably larger than those in normotensive subjects. Celiprolol decreased both systolic and diastolic pressure. It also decreased the levels of ΔHX and ΔAmm without changes in ΔLAC after an exercise. These findings also were confirmed by summation of each metabolite (ΣΔMetabolites). Celiprolol caused a marginal decrease of serum uric acid, but the difference was not statistically significant. On the other hand, nonvasodilating ß1 blockers did not suppress the levels of ΔHX and ΔAmm, whereas they significantly increased ΔLAC after an exercise. Celiprolol improved energy metabolism in skeletal muscles. It suppressed HX production and consequently did not adversely affect serum uric acid levels.

Synthesis of an azadioxa-planar triphenylborane and investigation of its structural and photophysical properties.

We report here the first successful synthesis of planar triphenylborane 1 with the phenyl groups bridged by oxygen and nitrogen atoms via double nucleophilic aromatic substitution reaction. The hetero atom-bridged 1 has excellent planarity. Its structural and photophysical properties are tunable by altering the bridging atoms.

Primary phacoemulsification and aspiration combined with 25-gauge single-port vitrectomy for management of acute angle closure.

PURPOSE: To describe a technique using phacoemulsification and aspiration (PEA) combined with 25-gauge single-port vitrectomy as a primary treatment for acute angle closure (AAC). METHODS: Seventeen consecutive cases of AAC were treated with 1) transconjunctival limited single-port vitrectomy with a 25-gauge vitrector and 2) transcorneal PEA and cortex removal followed by implantation of foldable intraocular lenses (IOL). RESULTS: Intraocular pressure (IOP) control was achieved in all 17 eyes examined. Mean preoperative IOP was 51.8+/-13.1 mmHg, and mean IOP on postoperative day 1 was 18.3+/-8.5 mmHg. Additional anti-glaucoma surgery was necessary in one eye. IOL could not be implanted because of zonular dialysis in one eye. Postoperative complications were seen in three cases (one retinal hemorrhage and two papilledema). CONCLUSIONS: The PEA procedure is efficient as a primary treatment of AAC. Single-port vitrectomy with a 25-gauge vitrector facilitated PEA and IOL implantation.

Quantitative evaluation of the pattern of shunt flow in the right ventricle and pulmonary artery of dogs with experimental ventricular septal defect.

Cineangiographic studies in patients with ventricular septal defect (VSD) have occasionally demonstrated that part of the blood across the defect is ejected immediately into the pulmonary artery (PA) passing through the outflow tract of the right ventricle (RV), but without being trapped in it. We attempted to make a quantitative evaluation of the flow of a partial shunt pathway (a direct VSD-PA pathway) that drains that part of the blood from the defect. Our method depended on a thermal dilution technique to obtain the ejection fraction of the RV and to observe a simultaneous pair of dilution curves at the roots of the aorta and PA after introduction of tracer into the left atrium. An analytical process was specially designed by incorporating a stable one-pass deconvolution technique. The method was applied to eight anesthetized dogs with acutely produced experimental VSD on the entrance of the outflow tract of the RV. The flow through the direct VSD-PA pathway was, in most cases, greater than 50 and up to 85% (mean of the eight, 57 +/- 5% SE) of the total left-to-right shunt flow. This would imply that less than 50%, and down to as little as 15%, of the total amount of shunt flow contributed to extra work of the RV in these cases. In addition, the impact on the pulmonary vasculature due to such a large amount of pulsatile flow through the direct VSD-PA pathway may accelerate the development of hypertrophy of the pulmonary vessel wall.

A fission yeast gene, him1(+)/dfp1(+), encoding a regulatory subunit for Hsk1 kinase, plays essential roles in S-phase initiation as well as in S-phase checkpoint control and recovery from DNA damage.

Saccharomyces cerevisiae CDC7 encodes a serine/threonine kinase required for G(1)/S transition, and its related kinases are present in fission yeast as well as in higher eukaryotes, including humans. Kinase activity of Cdc7 protein depends on the regulatory subunit, Dbf4, which also interacts with replication origins. We have identified him1(+) from two-hybrid screening with Hsk1, a fission yeast homologue of Cdc7 kinase, and showed that it encodes a regulatory subunit of Hsk1. Him1, identical to Dfp1, previously identified as an associated molecule of Hsk1, binds to Hsk1 and stimulates its kinase activity, which phosphorylates both catalytic and regulatory subunits as well as recombinant MCM2 protein in vitro. him1(+) is essential for DNA replication in fission yeast cells, and its transcription is cell cycle regulated, increasing at middle M to late G(1). The protein level is low at START in G(1), increases at the G(1)/S boundary, and is maintained at a high level throughout S phase. Him1 protein is hyperphosphorylated at G(1)/S through S during the cell cycle as well as in response to early S-phase arrest induced by nucleotide deprivation. Deletion of one of the motifs conserved in regulatory subunits for Cdc7-related kinases as well as alanine substitution of three serine and threonine residues present in the same motif resulted in a defect in checkpoint regulation normally induced by hydroxyurea treatment. The alanine mutant also showed growth retardation after UV irradiation and the addition of methylmethane sulfonate. In keeping with this result, a database search indicates that him1(+) is identical to rad35(+). Our results reveal a novel function of the Cdc7/Dbf4-related kinase complex in S-phase checkpoint control as well as in growth recovery from DNA damage in addition to its predicted essential function in S-phase initiation.

Regulation of initiation of S phase, replication checkpoint signaling, and maintenance of mitotic chromosome structures during S phase by Hsk1 kinase in the fission yeast.

Hsk1, Saccharomyces cerevisiae Cdc7-related kinase in Shizosaccharomyces pombe, is required for G1/S transition and its kinase activity is controlled by the regulatory subunit Dfp1/Him1. Analyses of a newly isolated temperature-sensitive mutant, hsk1-89, reveal that Hsk1 plays crucial roles in DNA replication checkpoint signaling and maintenance of proper chromatin structures during mitotic S phase through regulating the functions of Rad3 (ATM)-Cds1 and Rad21 (cohesin), respectively, in addition to expected essential roles for initiation of mitotic DNA replication through phosphorylating Cdc19 (Mcm2). Checkpoint defect in hsk1-89 is indicated by accumulation of cut cells at 30 degrees C. hsk1-89 displays synthetic lethality in combination with rad3 deletion, indicating that survival of hsk1-89 depends on Rad3-dependent checkpoint pathway. Cds1 kinase activation, which normally occurs in response to early S phase arrest by nucleotide deprivation, is largely impaired in hsk1-89. Furthermore, Cds1-dependent hyperphosphorylation of Dfp1 in response to hydroxyurea arrest is eliminated in hsk1-89, suggesting that sufficient activation of Hsk1-Dfp1 kinase is required for S phase entry and replication checkpoint signaling. hsk1-89 displays apparent defect in mitosis at 37 degrees C leading to accumulation of cells with near 2C DNA content and with aberrant nuclear structures. These phenotypes are similar to those of rad21-K1 and are significantly enhanced in a hsk1-89 rad21-K1 double mutant. Consistent with essential roles of Rad21 as a component for the cohesin complex, sister chromatid cohesion is partially impaired in hsk1-89, suggesting a possibility that infrequent origin firing of the mutant may affect the cohesin functions during S phase.

Inner segment ellipsoid band length is a prognostic factor in retinitis pigmentosa associated with EYS mutations: 5-year observation of retinal structure.

PurposeTo evaluate whether the length of the inner segment ellipsoid (ISe) band can be used as a prognostic factor for disease course in retinitis pigmentosa (RP) patients with EYS mutations by observation over a period of 5 years.MethodsTwelve RP patients with EYS mutations were studied. The horizontal and vertical ISe length of the right eye was manually measured at five time points annually, using spectral domain optical coherence tomography. A regression line through the five points from baseline to the final measurement was drawn and the ratio of the length (%) at each point to the baseline length was calculated; the slope was defined as the rate of ISe shortening (%/year). The correlation between the rate of ISe shortening and age, visual acuity, and mean deviation (MD) value were evaluated. The intraclass correlation coefficient (ICC) for the measurements was calculated.ResultsThe mean rate of ISe shortening was -4.65±2.89% per year and the decline was statistically significant. The rate of shortening was significantly negatively correlated with the baseline length (P=0.046, r=0.58), but not with the baseline age, visual acuity, and MD value. The ICC (2, 1) was 0.999.ConclusionsISe of all RP patients with EYS mutations shortened during the 5 years of annual observation. The measurement of the length of ISe is a simple and convenient method with high repeatability, and the length is a sensitive prognostic factor for the rate of ISe shortening in RP patients with EYS mutations.

Effects of Uric Acid on the NO Production of HUVECs and its Restoration by Urate Lowering Agents.

BACKGROUND: Although urate impaired the endothelial function, its underlying mechanism remains unknown. We hypothesized that urate impaired nitric oxide (NO) production in human umbilical vein endothelial cells (HUVECs) via activation of uric acid transporters (UATs). PURPOSE AND METHOD: In the present study, we studied effects of urate on NO production and eNOS protein expression in HUVEC cells in the presence and absence of urate lowering agents using molecular biological and biochemical assays. RESULTS: HUVECs expressed the 4 kinds of UATs, URATv1, ABCG2, MRP4 and MCT9. Exposure to urate at 7 mg/dl for 24 h significantly reduced production of NO. Pretreatment with benzbromarone, losartan or irbesartan normalized NO production. The same exposure resulted in dephosphorylation of endothelial NO synthase (eNOS) in HUVECs. Again pretreatment with benzbromarone, losartan or irbesartan abolished this effect. CONCLUSION: Urate reduced NO production by impaired phosphorylation of eNOS in HUVEC via activation of UATs, which could be normalized by urate lowering agents.

Effect of Antihypertensive Drugs on Uric Acid Metabolism in Patients with Hypertension: Cross-Sectional Cohort Study.

Background: Hypertension is a common complication in patients with gout and/or hyperuricemia. Besides, hyperuricemia is a risk factor of gout as well as ischemic heart disease in hypertensive patients. Moreover, the risk of gout is modified by antihypertensive drugs. However, it remains unclear how antihypertensive agents affect uric acid metabolism. Purpose: In the present study, we investigated the uric acid metabolism in treated hypertensive patients to find out whether any of them would influence serum levels of uric acid. Patients and methods: 751 hypertensive patients (313 men and 438 women) under antihypertensive treatment were selected. Blood pressure (BP), serum uric acid (SUA) and serum creatinine (Scr) were measured and evaluated statistically. Results: In patients treated with diuretics, beta-blockers and/or alpha-1 blockers SUA levels were significantly higher than in patients who were not taking these drugs. Besides, the estimated glomerular filtration rate (eGFR) in patients treated with diuretics, beta-blockers and/or alpha-1 blockers was negatively correlated with SUA level. There were gender differences in the effects of beta-blockers and alpha-1 blockers. Multiple regression analysis indicated that both diuretics and beta-blockers significantly contributed to hyperuricemia in patients with medication for hypertension. Conclusion: Diuretics, beta-blockers and alpha-1 blockers reduced glomerular filtration rate and raised SUA levels. Calcium channel blockers, ACE inhibitors and angiotensin receptor blockers, including losartan, did not increase SUA levels.

Enhancing effects of salicylate on tonic and phasic block of Na+ channels by class 1 antiarrhythmic agents in the ventricular myocytes and the guinea pig papillary muscle.

OBJECTIVE: To study the interaction between salicylate and class 1 antiarrhythmic agents. METHODS: The effects of salicylate on class 1 antiarrhythmic agent-induced tonic and phasic block of the Na+ current (INa) of ventricular myocytes and the upstroke velocity of the action potential (Vmax) of papillary muscles were examined by both the patch clamp technique and conventional microelectrode techniques. RESULTS: Salicylate enhanced quinidine-induced tonic and phasic block of INa at a holding potential of -100 mV but not at a holding potential of -140 mV; this enhancement was accompanied by a shift of the hinfinity curve in the presence of quinidine in a further hyperpolarized direction, although salicylate alone did not affect INa. Salicylate enhanced the tonic and phasic block of Vmax induced by quinidine, aprindine and disopyramide but had little effect on that induced by procainamide or mexiletine; the enhancing effects were related to the liposolubility of the drugs. CONCLUSIONS: Salicylate enhanced tonic and phasic block of Na+ channels induced by class 1 highly liposoluble antiarrhythmic agents. Based on the modulated receptor hypothesis, it is probable that this enhancement was mediated by an increase in the affinity of Na+ channel blockers with high lipid solubility to the inactivated state channels.

Hemodynamic basis for the acute cardiac effects of troglitazone in isolated perfused rat hearts.

Troglitazone is a thiazolidinedione used for the treatment of NIDDM and potentially for other insulin-resistant disease states. Troglitazone has recently been shown to increase cardiac output and stroke volume in human subjects. These actions are thought to be mediated by the reduction of peripheral resistance, but a potential direct effect on cardiac function has not been studied. Therefore, we investigated the direct cardiac hemodynamic effects of troglitazone in isolated perfused rat hearts. Five groups of hearts were studied. Hearts were tested under isovolumetric contraction with a constant coronary flow, and troglitazone (0.2, 0.5, and 1.0 micromol) was administered by bolus injection. Peak isovolumetric left ventricular pressure (LVPmax), peak rate of rise of LVP (dP/dt(max)), and peak rate of fall of LVP (dP/dt(min)) were significantly increased 1 min after troglitazone administration in a dose-dependent manner, while the heart rate (HR) and coronary perfusion pressure (CPP) were significantly decreased (P < 0.05). HR was then fixed by pacing and/or CPP was fixed with nitroprusside to eliminate any effect of the two variables on the action of troglitazone. With constant HR and/or constant CPP, the effect of troglitazone on LVPmax, dP/dt(max), and dP/dt(min) was still unchanged. In addition, the positive inotropic, positive lusitropic, and negative chronotropic actions of troglitazone were not influenced even when hearts were pretreated with prazosin, propranolol, or nifedipine. In conclusion, troglitazone has direct positive inotropic, positive lusitropic, negative chronotropic, and coronary artery dilating effects. The inotropic and chronotropic actions of troglitazone are not mediated via adrenergic receptors or calcium channels. These findings have important clinical implications for diabetic patients with congestive heart failure.

Applicability of anti-neovascular therapy to drug-resistant tumor: suppression of drug-resistant P388 tumor growth with neovessel-targeted liposomal adriamycin.

Anti-neovascular therapy, one of the effective anti-angiogenic chemotherapy, damages new blood vessels by cytotoxic agents delivered to angiogenic endothelial cells and results in indirect eradication of tumor cells. We previously reported that liposomes-modified with a pentapeptide, Ala-Pro-Arg-Pro-Gly (APRPG-Lip) homing to angiogenic site, highly accumulated in tumor tissue, and APRPG-Lip encapsulating adriamycin (APRPG-LipADM) effectively suppressed tumor growth in tumor-bearing mice. In the present study, we examined the topological distribution of fluorescence-labeled APRPG-LipADM as well as TUNEL-stained cells in an actual tumor specimen obtained from Colon 26 NL-17 carcinoma-bearing mice. The fluorescence-labeled APRPG-Lip dominantly localized to vessel-like structure: a part of which was also stained with anti-CD31 antibody. Furthermore, TUNEL-stained cells were co-localized to the same structure. These data indicated that APRPG-LipADM bound to angiogenic endothelial cells and induced apoptosis of them. We also investigated the applicability of anti-neovascular therapy using APRPG-LipADM to ADM-resistant P388 solid tumor. As a result, APRPG-LipADM significantly suppressed tumor growth in mice bearing the ADM-resistant tumor. These data suggest that APRPG-LipADM is applicable to various kinds of tumor including drug-resistant tumor since it targets angiogenic endothelial cells instead of tumor cells, and eradicates tumor cells through damaging the neovessels.

Slow recovery of conduction velocity from use dependent inhibition induced by quinidine in guinea pig ventricular myocardium.

STUDY OBJECTIVE: The aim was to investigate whether the use dependent effects of antiarrhythmic drugs on the Na+ current could be applied to explain their effects on impulse conduction. DESIGN: Trains of rapid stimuli were applied to guinea pig papillary muscles via an electrode in the presence of quinidine (20 and 60 mumol.litre-1), and the conduction velocity was determined from the time difference between two signals of the maximal rate of rise (dV/dtmax) of the action potentials at two separate sites. The relationship of the time constants of the onset and recovery from the use dependent inhibition induced by quinidine was determined for the dV/dtmax and the conduction velocity. EXPERIMENTAL MATERIAL: Six male Hartley guinea pigs weighing 200 to 300 g were killed by a blow to the head and the papillary muscles were rapidly excised from the right ventricles. The preparations were superfused with Tyrode solution. MEASUREMENTS AND MAIN RESULTS: The rate of onset of the use dependent inhibition of conduction velocity and that of the square of conduction velocity were both faster than the simultaneously measured rate of onset of dV/dtmax inhibition induced by 20 mumol.litre-1 quinidine at high frequency stimulation. The relation between the rates of onset of the use dependent inhibition of conduction velocity (and the square of conduction velocity) and dV/dtmax became weak with low frequency stimulation and in the presence of 60 mumol.litre-1 quinidine. However, the recovery of conduction velocity (and the square of conduction velocity) from quinidine induced use dependent blockade, as measured by the extrastimulation method, appeared to be slower than the recovery of dV/dtmax. These results may be explained by a transient change in intracellular and intercellular conditions, such as an increase in internal resistance. CONCLUSIONS: The onset and recovery of the use dependent inhibition of conduction by antiarrhythmic drug may not always parallel the changes of the dV/dtmax of action potential in multicellular muscle preparations.

Marker of lipid peroxidation related to diabetic nephropathy in Indonesian type 2 diabetes mellitus patients.

OBJECTIVE: Even though diabetes patients exhibit an increased oxidative stress, its correlation with diabetic nephropathy is not fully understood. The purpose of this study was to determine whether lipid peroxidation marker correlates well with eGFR and UACR in type 2 diabetes mellitus patients. METHODS: We collected urine and serum samples of Indonesian type 2 diabetes mellitus outpatients with normo- and microalbuminuria at a Local Government Clinic (from ages: 39-74 years). Urinary 8-iso-PGF2α was measured by ELISA, the serum malondialdehyde by TBARS assay, and urinary albumin by BCG albumin assay. eGFR was calculated using the corrected-Cockcroft-Gault (CG), MDRD, and CKD-EPI equation. Other necessary data were obtained through questionnaires. RESULTS: The results showed that the increasing level of malondialdehyde was mildly correlated with the decline in eGFR (MDRD). In contrary, there was a significant positive correlation between 8-iso-PGF2α concentration and eGFR based on the corrected-CG, MDRD study, and CKD-EPI equation (r=0.457, p<0.001; r=0.424, p<0.001; r=0.443, p<0.001). This relationship still persisted in the normoalbuminuric subjects (n=43) (r=0.491, p=0.001; r=0.461, p=0.002; r=0.455, p=0.002). The multivariate analysis showed that 8-iso-PGF2α together with fasting plasma glucose was the most predictive factor for the high 2-quantile eGFR (adjusted OR 1.001, (95% CI, 1.000-1.001)). However, there was no significant correlation between UACR with malondialdehyde (r=0.268, p=0.050) and 8-iso-PGF2α(r=-0.030, p=0.808). UACR itself was inversely correlated with eGFR based on the corrected-CG, the MDRD, and CKD-EPI (r=-0.232, p<0.05; r=-0.228, p<0.05; r=-0.232, p<0.05). CONCLUSIONS: Increased 8-iso-PGF2α and malondialdehyde in type 2 diabetes mellitus patients may play a role in the pathophysiologic significance of diabetic nephropathy, even while considering the effect of potential confounders.

Treatment with mild brain hypothermia for cardiopulmonary resuscitation after myoclonic seizures in infant with robertsonian type of trisomy 13.

Congenital chromosomal abnormality with trisomy 13 is known to be associated with poor life prognosis and lethal. Therefore, physician advice the patients be kept in intensive treatment with resuscitation and state of the art intensive care when sudden change in the general condition with this trisomy is observed. We report herein, the treatment with mild brain hypothermia therapy for cardiopulmonary resuscitation after myoclonic seizures in infant with Robertsonian type of trisomy 13 in intensive care unit. Our study indicated that brain hypothermia therapy and steroid pulse therapy on an infant who was believed to have post-resuscitation hypoxic encephalopathy was highly effective as the patient's general condition recovered to the original state after four months.

Impaired cytosolic Ca2+ response to glucose and gastric inhibitory polypeptide in pancreatic beta-cells from triphenyltin-induced diabetic hamster.

Oral administration of a single dose of triphenyltin compounds induces diabetes with decreased insulin secretion in rabbits and hamsters after 2-3 days without any morphological changes in pancreatic islets. In the present study, to test the possibility that the impaired insulin secretion induced by triphenyltin compounds could result from an impaired Ca2+ response in pancreatic beta-cells, we investigated the effect of triphenyltin-chloride (TPTCl) administration on the changes in the cytoplasmic Ca2+ concentration ([Ca2+]i) induced by secretagogues, such as glucose, high K+, gastric inhibitory polypeptide (GIP), and acetylcholine (ACh) in hamster pancreatic beta-cells. TPTCl administration caused partial suppression in 10 mM K+-induced rise in [Ca2+]i without suppressing the increase in [Ca2+]i evoked by 20-50 mM K+. Administration of TPTCl strongly inhibited the rises in [Ca2+]i induced by 27.8 mM glucose, 100 microM ACh in the presence of 5.5 mM glucose, and by 100 nM GIP in the presence of 5.5 mM glucose. In the ACh-induced response, TPTCl administration strongly suppressed the late sustained phase, while weakly suppressing the initial rise in [Ca2+]i. TPTCl administration significantly suppressed the rise of cAMP content in islet cells induced by 100 nM GIP with 1 mM 3-isobutyl-1-methylxanthine in the presence of 5.5 mM glucose (P < 0.01, N = 5-11). TPTCl administration also impaired the insulin secretion in islet cells induced by 27.8 mM glucose, 100 nM GIP in the presence of 5.5 mM glucose, and 100 microM ACh in the presence of 5.5 mM glucose (P < 0.05, N = 9-16). We conclude that the pathology of triphenyltin-induced diabetes in hamsters involves a defect in cellular Ca2+ response due to a reduced Ca2+-influx through voltage-gated Ca2+ channels.

The hemodynamic basis for the cardiac effects of parathyroid hormone (PTH) and PTH-related protein.

PTH and PTH-related protein (PTHrP) have been regarded to have positive inotropic effects on the heart as well as positive chronotropic and vasodilator effects. However, inotropy due to a direct effect of these peptides has not heretofore been distinguished from an indirect inotropic effect as a result of altered heart rate or coronary flow. The aim of this study was to determine whether PTH and PTHrP have direct inotropic effects in isolated perfused rat hearts. Three groups of hearts were studied; in all groups, hearts contracted isovolumically and were perfused with a constant coronary pressure. In the control group, heart rate, coronary flow, peak pressure (LVPmax), peak rate of rise of LV pressure (dP/dtmax), and peak intracellular calcium (measured by aequorin) all increased with PTH and PTHrP in a dose-dependent manner. When heart rate was fixed by pacing in a second group of rats, PTH and PTHrP increased coronary flow, LVPmax, and dP/dtmax significantly, indicating that inotropic actions were not mediated solely by chronotropic effects. However, when heart rate was fixed by pacing and, additionally, coronary flow was held constant (by maximal prevasodilation with nitroprusside) in a third group of rats, there was no significant effect of either PTH or PTHrP on LVPmax, dP/dtmax, or peak intracellular calcium. To demonstrate the responsiveness of this latter preparation to inotropic stimulation, the beta-adrenergic agonist, isoproterenol, increased LVPmax, dP/dtmax, and peak calcium even when heart rate was fixed and vasodilation was maximal. Thus, PTH and PTHrP are inotropic agents by virtue of their influence on coronary flow and heart rate, but not by any direct effect on contractile elements in the heart.

Progesterone inhibits superoxide radical production by mononuclear phagocytes in pseudopregnant rats.

This study investigated the changes in superoxide radical production by mononuclear phagocytes in the corpus luteum (CL) during pseudopregnancy in rats. Activity of superoxide radical production was determined by the conversion of nitro blue tetrazolium (NBT) to blue formazan deposit. Rats received 10 mg NBT via the abdominal aorta on day 3, 7, or 13 of pseudopregnancy and were autopsied 1 min later to prepare the histological sections. The cells with blue formazan deposits (NBT-positive cells) in the CL were scarce on days 3 and 7 of pseudopregnancy and significantly increased on day 13 of pseudo-pregnancy. On the other hand, simultaneous administration of 100 micrograms phorbol 12-myristate 13-acetate, which activates mononuclear phagocytes to produce superoxide radical, significantly increased the numbers of NBT-positive cells in the CL on day 7 of pseudopregnancy, but not in the CL on day 3 or 13 of pseudopregnancy. To study the possibility that superoxide radical production by mononuclear phagocytes is inhibited by progesterone on day 7 of pseudopregnancy, peritoneal mononuclear phagocytes prepared on day 7 or 13 of pseudopregnancy were preincubated with 10, 50, or 100 ng/ml progesterone for 6 h and then stimulated with phorbol 12-myristate 13-acetate. Superoxide radical production was measured by the cytochrome c reduction method. One hundred nanograms per ml progesterone significantly inhibited superoxide radical production by mononuclear phagocytes, and this inhibitory effect of progesterone was significantly blocked by the simultaneous addition of RU486 (10(-7) M). These results suggested that progesterone inhibited superoxide radical production by the mononuclear phagocytes in the CL during midpseudopregnancy in rats.

Circulatory pressure-volume relationship and cardiac output in DOCA-salt rats.

We studied the total vascular pressure-volume relationship and cardiac output (CO) in conscious rats receiving DOCA-salt or sham treatment. The mean circulatory filling pressure (MCFP) was measured by briefly inflation an indwelling balloon in the right atrium, and the MCFP-blood volume (BV) relationship over +/- 10% of BV was determined by rapid blood infusion or withdrawal. CO was measured in separate experiments using Fick's principle. Arterial pressure-volume relationship was also determined in additional experiments on anesthetized rats. Compared with sham rats, the mean arterial pressure was unchanged at 1 week, increased at 2 weeks, and increased further thereafter in the DOCA-salt rats. The BV was unchanged at 1 week, expanded at 2 weeks, unchanged at 5 weeks, and contracted at 8 weeks. There were no significant changes in MCFP, total vascular compliance (the inverse of the slope), nor unstressed volume (extrapolated volume axis intercept) at 2, 5, and 8 weeks. Total vascular capacity, assessed as BV at MCFP of 7.6 mm Hg, increased at 2 weeks, was unchanged at 5 weeks, and decreased at 8 weeks. Arterial compliance decreased at 5 and 8 weeks. CO remained unaltered at 1, 2, 5, and 8 weeks. These results suggest that the altered total vascular capacity may serve to maintain a normal CO against a rising afterload in the conscious DOCA-salt hypertensive rats, and that the decreased total vascular capacity may be a secondary hemodynamic feature with progression of hypertension.

The storage form of human renal renin.

We isolated renin granules from cadaver kidneys using discontinuous sucrose density gradient centrifugation, and investigated the storage form of the renin from these granules. Approximately 23% of the total renin activity in the original homogenate was obtained from the surface phase between 1.6 and 1.7 M sucrose (Fraction 6). Granule renin extracted from the granules in Fraction 6 was separated into active and inactive renin using pepstatin affinity chromatography. Only the active renin had an affinity for pepstatin. The inactive renin, albeit activated by trypsin, was little activated by acidification. The proportion of inactive renin was about 25% of the total granule renin (active renin + inactive renin). Trypsin concentrations over 10 micrograms/ml resulted in a decrease in the renin activity of the trypsin-activated renin, but the enzymatic activity of active renin was decreased by trypsin. With gel filtration, the inactive renin revealed a single peak, and the molecular weight (MW) was 48,000. The active renin had a MW of 44,000. The inactive renin could be activated by trypsin without an apparent change in molecular weight.