Assessment of the Diuretic Properties of Rice Bean Accessions Using a Mouse Model and Identification of Active Polyphenolic Compounds.

Rice bean [Vigna umbellata (Thunb.) Ohwi and Ohashi], an annual legume in the genus Vigna, is a promising crop suitable for cultivation in a changing climate to ensure food security. It is also a medicinal plant widely used in traditional Chinese medicine; however, little is known about the medicinal compounds in rice bean. In this study, we assessed the diuretic effect of rice bean extracts on mice as well as its relationship with the contents of eight secondary metabolites in seeds. Mice gavaged with rice bean extracts from yellow and black seeds had higher urinary output (5.44-5.47 g) and water intake (5.8-6.3 g) values than mice gavaged with rice bean extracts from red seeds. Correlation analyses revealed significant negative correlations between urine output and gallic acid (R = -0.70) and genistein (R = -0.75) concentrations, suggesting that these two polyphenols negatively regulate diuresis. There were no obvious relationships between mice diuresis-related indices (urine output, water intake, and weight loss) and rutin or catechin contents, although the concentrations of both of these polyphenols in rice bean seeds were higher than the concentrations of the other six secondary metabolites. Our study findings may be useful for future research on the diuretic effects of rice bean, but they should be confirmed on the basis of systematic medical trials.

Assessment of renal function in the anaesthetised rat following injection of superparamagnetic iron oxide nanoparticles.

A recent study showed that a significant fall in mean arterial pressure (MAP) occurred following intravenous injection of two novel superparamagnetic iron oxide nanoparticles (SPIONs), MF66 and OD15. To assess if this was caused by excessive glomerular clearance, the effect of both particles on renal function was studied. Experiments were performed on sodium pentobarbital anaesthetised male Wistar rats (250-350 g). Twenty-minute urine clearances were taken followed by an i.v. bolus of MF66, OD15 (2 mg·kg-1), or dH2O (0.4 mL·kg-1). MF6 or OD15 injection resulted in a significant transient drop in MAP and renal blood flow by approximately 33% and 50% (P < 0.05). The absolute excretion of sodium was significantly increased (P < 0.05) by almost 80% and 70% following OD15 and MF66, respectively. Similarly, fractional excretion of sodium was increased by almost 80% and 60% following OD15 and MF66, respectively. The glomerular filtration rate was not significantly affected, but urine flow increased nonsignificantly by approximately 50% and 66% following i.v. injection of OD15 and MF66, respectively. SPIONs produce a decrease in blood pressure and a natriuresis; however, the rate of fluid filtration in the kidney was not significantly affected.

Diuretics prescribing in chronic kidney disease patients: physician assessment versus bioimpedence spectroscopy.

INTRODUCTION: The relationship between hypertension and fluid overload in pre-dialysis CKD patients need to be elucidated. Current study aimed to find relationship between fluid overload and hypertension along with prescribed diuretic therapy using bioimpedance spectroscopy (BIS). METHODOLOGY: A prospective observational study was conducted by inviting pre-dialysis CKD patients. Fluid overload was assessed by BIS. RESULTS: A total of 312 CKD patients with mean eGFR 24.5 ± 11.2 ml/min/1.73 m2 were enrolled. Based on OH value ≥7 %, 135 (43.3 %) patients were hypervolemic while euvolemia was observed in 177 (56.7 %) patients. Patients were categorized in different regions of hydration reference plot (HRP) generated by BIS i.e., 5.1 % in region-N (normal BP and fluid status), 20.5 % in region I (hypertensive with severe fluid overload), 29.5 % in region I-II (hypertensive with mild fluid overload), 22 % in region II (hypertensive with normohydration), 10.2 % in region III (underhydration with normal/low BP) and 12.5 % in region IV (normal BP with severe fluid overload). A total of 144 (46 %) patients received diuretics on basis of physician assessment of BP and edema. Maximum diuretics 100 (69.4 %) were prescribed in patients belonging to regions I and I-II of HRP. Interestingly, a similar number of diuretic prescriptions were observed in region II (13 %) and region IV (12 %). Surprisingly, 7 (4.9 %) of patients in region III who were neither hypervolemic nor hypertensive were also prescribed with diuretics. CONCLUSION: BIS can aid clinicians to categorize CKD patients on basis of their fluid status and provide individualized pharmacotherapy to manage hypertensive CKD patients.

Special focus on the role of α(1D)-adrenoreceptors in the assessment of renal tubular sodium re-absorptive responses in spontaneously hypertensive rats subjected to high sodium diet.

α(1D)-adrenoceptors are involved in the genesis/maintenance of hypertension in spontaneously hypertensive rats (SHR). This study aims to investigate the role of α(1D)-adrenoceptors in the antinatriuretic and antidiuretic responses in SHR subjected to high sodium (SHRHNa) and normal sodium (SHRNNa) intake for six weeks. Renal inulin clearance study was performed in which the antinatriuretic and antidiuretic responses to phenylephrine were examined in the presence and absence of α(1D)-adrenoceptors blocker BMY7378. Data, mean±S.E.M. were subjected to ANOVA with significance at p<0.05. Results show that feeding SHR for six weeks with high salt did not cause any change in blood pressure. SHRHNa had higher (all p<0.05) urine flow rate (UFR), fractional and absolute excretion of sodium (FE(Na) and U(Na)V) compared to SHRNNa. Phenylephrine infusion produced significant reduction in UFR, FE(Na) and U(Na)V in both SHRHNa and SHRNNa. The antidiuretic and antinatriuretic responses to phenylephrine in both groups were attenuated in the presence of BMY7378. Moreover, the antidiuretic and antinatriuretic responses to phenylephrine and BMY7378 were independent on any significant changes in renal and glomerular hemodynamics in both groups. Thus we conclude that high sodium intake did not bring any further increase in blood pressure of SHR, however, it results in exaggerated natriuresis and diuresis in SHRHNa. Irrespective of dietary sodium changes, α1-adrenoceptors are involved in mediating the antinatriuretic and antidiuretic responses to phenylephrine in SHR. Further, high sodium intake did not significantly influence the functionality of α(1D)-adrenoceptors in mediating the adrenergically induced antinatriuresis and antidiuresis.

Performing repeated noninvasive bedside measures of volume response to intravenous furosemide in acute pulmonary edema: a feasibility assessment.

Optimizing responses to intravenous furosemide (ivF) in acute pulmonary edema is limited by current insensitive noninvasive means of volume assessment. We conducted a pilot study to assess the feasibility of performing repeated measures of echocardiographic and bioimpedance analysis (BIA) parameters and test their response as noninvasive markers of volume response to ivF. We also aimed to identify the most potentially sensitive markers of this response. Patients receiving ivF for a clinical diagnosis of acute cardiogenic pulmonary edema were studied. Echocardiographic and BIA parameters were measured at 0, 0.5, 1, 2, and 3 h after ivF. Intraobserver variability for each parameter was determined. Thirty-one patients were enrolled who were receiving 40-100 mg of ivF. Transmitral (MV) early peak velocity following Valsalva maneuver and transtricuspid (TV) early peak velocity reduced significantly (P= 0.012 and 0.010, respectively), whereas MV deceleration time increased significantly (P= 0.006) in response to ivF. Short-axis inferior vena cava diameter (SIVC) in expiration and inspiration and SIVC corrected for body surface area in expiration and inspiration reduced significantly following ivF (P= 0.039, 0.020, 0.032, and 0.016, respectively). BIA estimates of extracellular water decreased significantly (P= 0.001), whereas impedance (Z) at currents of 5, 50, 100, and 200 kHz increased following ivF; the changes were significant with all but the last parameter (P < 0.0001, 0.006, 0.010, and 0.051, respectively). Maximal change from baseline for each parameter was greater than its respective intraobserver variability. Performing repeated measures of echocardiographic and BIA parameters is feasible in this unstable group of patients. The above panel of parameters could potentially be used to track volume response to ivF and, thus, to optimize treatment in acute pulmonary edema.

[Comparative economic and clinical effectiveness of setegis and camiren in therapy of chronic prostatitis]. / Sravnitel'naia ekonomicheskaia i klinicheskaia effektivnost' primeneniia setegisa i kamirena pri lechenii khronicheskogo prostatita.

The drugs setegis 2 mg, camiren 2 mg, were used in the investigation designed to study economic and clinical effectiveness of employment of alpha-blockers for treating chronic prostatitis, with the expediency of the above therapeutic modality having been corraborated by the findings secured. Objective control of the treatments administered necessitates studying the time-related changes in indices for the amount of the residual urine and volume of the prostate. Economic expediency has been shown of use of camiren 2 mg, an alpha-blocker, of the KRKA firm, which fact was validated by a lower cost of the drug at the retail market of Ukraine compared to setegis 2 mg.

Electrophysiological assessment of sensations arising from the bladder: are there objective criteria for subjective perceptions?

PURPOSE: Initial bladder filling sensation, first and strong desire to void are subjective perceptions that occur periodically during the urine storage mode of bladder function, representing sensory input from the lower urinary tract. To our knowledge methods for evaluating sensory bladder function are not available. We studied a simple electrophysiological procedure for the objective assessment of bladder sensations using sympathetic skin responses and surface pelvic floor electromyography. MATERIALS AND METHODS: Informed consent was provided by 8 healthy male subjects, who were administered 20 mg. furosemide and 1 l. fluid to drink. Palmar and plantar sympathetic skin responses, and surface pelvic floor electromyogram were continuously recorded during bladder filling, voluntary pelvic floor contraction and voiding. RESULTS: First desire to void evoked simultaneous sympathetic skin responses and pelvic floor contractions. This pattern appeared periodically with the desire to void sensation as well as with strong desire to void at maximum bladder capacity and it correlated well with the subjective sensation of the subjects. Voluntary pelvic floor contraction decreased the subjective intensity of the desire to void sensation as well as sympathetic skin response activity for the same short period. During voiding sympathetic skin responses almost complete absence of sympathetic skin responses was observed. CONCLUSIONS: Sensations arising from the bladder induce combined activation of sympathetic skin responses and pelvic floor activity. This coherence indicates synchronized activation and inactivation of the autonomic and somatic pathways necessary for appropriate urine storage and coordinated voiding. Our observations may introduce a new approach for objectively assessing subjective sensations arising from the urinary tract.

Renal adenosine A3 receptors in the rat: assessment of functional role.

The functional roles of adenosine A3 receptors in the rat kidney were assessed for the first time with respect to A1 receptor-mediated responses. Utilizing a chronically instrumented conscious rat preparation, we tested renal excretory responses to acute administration of the A3 receptor antagonists 3-ethyl-5-benzyl-2-methyl-6-phenyl-4-phenylethynyl-1 ,4-(+)-dihydropridine-3,5-dicarboxylate (MRS-1191) and 9-chloro-2-(2-furyl)-5-phenylacetylamino-[1,2,4]-triazolo[1,5-c]qu inazoline (MRS-1220) with reference to the effects of the A1 receptor antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX). The intravenous administration of DPCPX resulted in significant increases in fluid and sodium excretions without affecting glomerular filtration rate (GFR). This suggests that DPCPX-induced diuretic and natriuretic responses are related to decreased tubular reabsorption. However, neither MRS-1191 nor MRS-1220 alone affected fluid or sodium excretions, or GFR, indicating lack of an effect of either compound on renal function. On the other hand, the co-administration of MRS-1220 with DPCPX abolished both the diuretic and natriuretic responses to DPCPX, being suggestive of antagonism between these two compounds. MRS-1191, however, did not affect the DPCPX-induced fluid and sodium excretions. Neither the A1 nor the A3 receptor antagonists altered potassium excretion individually or in combination. The data suggest that while adenosine A1 receptors are involved in the regulation of renal fluid and sodium transport, A3 receptors do not appear to have a major role in regulation of renal excretory function under baseline physiological conditions.

Bioavailability assessment of arginine-vasopressin (AVP) using pharmacokinetic-pharmacodynamic (PK-PD) modeling in the rat.

A novel method of assessing the extent of oral bioavailability of arginine-vasopressin (AVP) from pharmacological data was presented. After intravascular administration (i.v. bolus or short-term infusion) of AVP to rats, the relationship between blood concentrations and its effect on both mean arterial pressure (hemodynamic effect) and urinary sodium concentration (anti-diuretic effect) was described on the basis of an integrated pharmacokinetic-pharmacodynamic (PK-PD) model. A direct model was used for the hemodynamic response, while an indirect response model, rather than a hypothetical link model was used for the anti-diuretic response. A sigmoid Emax model was applied to describe the drug-receptor interaction. Pharmacological responses after intravascular administration of AVP were reasonably described by the PK-PD model. However, PD parameters estimated by the PK-PD analysis suggested that apparent receptor affinity rather than efficacy in i.v. bolus study was significantly higher than that in the short-term infusion study. This fact indicated that PK-PD relationship was influenced by the intravascular input rate of AVP. We then investigated the relationship between plasma concentration and amount of AVP bound to the V2 receptors in the kidney. The result indicated that the amount of AVP bound to the receptors after i.v. bolus injection was always greater than that after short-term infusion. Since the PK-PD relationship after oral administration was almost identical with that after short-term infusion, the PK-PD model obtained in the short-term infusion study was used to assess the extent of oral bioavailability (EBAPp.o.). The EBAp.o. values, estimated from pharmacological effects (hemodynamic effect and anti-diuretic effect) after oral administration of 5 microg/kg of AVP were 0.68% to 0.93% and were almost identical with the actual EBAPp.o. value (0.81%). From these results, we concluded that oral bioavailability of AVP was reasonably predicted by the PK-PD model, provided that appropriate pharmacological effects and appropriate intravascular dosing rate as a reference formulation are available. The method may be an alternative to methods based on plasma concentrations, when drug concentration cannot be measured and when appropriate pharmacological data are available.

Assessment of echocardiographic left ventricular mass before and after acute volume depletion.

Left ventricular mass calculations are often performed to assess the need or effectiveness of antihypertensive drug therapy. However, there are multiple potential errors that may affect the accuracy of these calculations, which can possibly include acute changes in preload. Therefore, to assess the hypothesis that acute volume depletion might alter calculated left ventricular mass, 15 normotensive healthy male volunteers underwent standard M-mode echocardiographic evaluations (at the level of the chordae tendineae guided by two-dimensional echocardiography) before and 2 h after 40 mg of intravenous furosemide. One patient was eliminated due to hypotension prior to the final echocardiogram. The echocardiograms were blinded to patient identity and the time sequence and read separately by two investigators. Four to five cycles were read per echocardiogram by each investigator. All values measured were the mean of the two investigators. Echocardiographic measurements were derived by both the American Society of Echocardiography and Penn conventions. An average urine volume of 1728 mL was collected, and the mean weight change 2 h after furosemide administration was 1.78 kg (P = .001). Penn left ventricular diastolic diameter (1.8 mm, P = .015) and left ventricular mass index (10 g/m2, P = .04) were significantly decreased; however, there was no significant change in septal, posterior, or relative wall thicknesses. As it is unreasonable to believe that acute remodeling of the left ventricle resulted in a decline in left ventricular mass in 2 hours, it is concluded that acute volume changes resulted in a decrease in left ventricular mass measurement due to the influence of diastolic diameter on the calculation of cardiac mass.

[The permeability of the barrier of the gastrointestinal tract for the macromolecules of polyethylene glycol-4000: an assessment of the mechanism and its reproducibility]. / Pronitsaemost' bar'era zheludochno-kishechnogo trakta dlia makromolekul poliétilenglikolia-4000: otsenka mekhanizma i vosproizvodimosti.

Polyethylene glycol (PEG)-4000 is proposed as a tracer of intestinal macromolecular permeability. The reproducibility of permeability testing with PEG-4000 and the mechanism of its penetration through intestinal mucosa were studied in adult rats. Permeability measurement for PEG-4000 was reproducible when repeated twice for 2 days. This makes it possible to repeat PEG-4000 permeability testing before and after any experimental impact on the intestine. I.p. administration of colchicine to rats (125 micrograms/100 g b. w.) significantly inhibited intestinal absorption of PEG-4000 fed to the animals 3 hours later. Hence, PEG-4000 penetration through the intestinal mucosa is mediated by the system of enterocyte cytoplasmic microtubules. Mucosal permeability for PEG-4000 may be consequently considered as a valuable model of permeability for protein macromolecules.

Assessment of the acute acrylonitrile-induced neurotoxicity in rats.

Acrylonitrile (VCN) is an aliphatic nitrile which is used extensively in manufacturing of synthetic fibers, plastics, and rubber. Although the neurotoxicity of VCN is recognized, no thorough characterization of this effect has been reported. Current studies were designed to quantitatively characterize the acute phase of VCN-induced cholinomimetic neurotoxicity, and to determine the effects of dose, route of administration, and atropine on such toxicity. Administration of a single gavage or subcutaneous doses of 20, 40, or 80 mg VCN/kg to male Sprague-Dawley rats causes two distinctive phases of acute neurotoxic effects. Signs observed in the early phase had a rapid onset, and were cholinomimetic in nature. They included salivation, lacrimation, chromodacryorrhea, polyuria, miosis, vasodilatation in face, ears and extremities, increased gastric secretion, and diarrhea. A late phase developed hours after VCN dosing, and the toxic signs included depression, convulsions, and respiratory failure followed by death at high doses. These results revealed that the cholinomimetic toxicity induced by VCN was dose related regardless of the route of administration. In another study, rats were pretreated with atropine (1 mg/kg, IP) prior to VCN (40 mg/kg) in order to investigate the role of the cholinergic system. Atropine protected rats against VCN-induced cholinomimetic neurotoxicity, suggesting possible involvement of the cholinergic system. Finally, this work provides essential basic information for studying the biochemical, pharmacological, and neurological basis of VCN-induced neurotoxicity in the rat.

Morphometric, biochemical, and physiological assessment of perinatally induced renal dysfunction.

Three chemicals, known either to alter renal development when administered during fetal development or to affect renal function when administered to adult rats, were administered to Sprague-Dawley rats at critical periods of renal development. Chlorambucil (CHL) was administered ip on d 11 of gestation at doses of 0, 3, and 6 mg/kg; nitrofen (2,4-dichlorophenyl p-nitrophenyl ether) (NIT) was given po on d 8-16 of gestation at 0, 4.17, 12.5, and 25 mg/kg . d; and mercuric chloride (MER) was given sc on postnatal d 1 at 0, 14, and 28 micrograms/pup. To assess the effects of these toxicants on the functional development of the kidneys, a diuresis test with and without antidiuretic hormone was applied on postnatal d 3 (PD 3); a hydropenia test on PD 6; and kidney weights, glomerular counts in midhilar cross sections, and the specific activity of renal alkaline phosphatase were determined on PD 3 and 6. Data from pups with obvious malformations of the kidneys was eliminated from the statistical analyses of the data so that emphasis could be placed on alterations of functional development in individuals with apparently morphologically normal kidneys. CHL retarded the growth and biochemical differentiation of the kidney at 6 mg/kg. Pups from this treatment groups showed an attenuated response to exogenously administered antidiuretic hormone. NIT impaired growth and altered renal morphology at a dose of 12.5 mg/kg . d and altered physiological responses in the absence of anatomical changes at a dose of 4.17 mg/kg . d. MER, at doses near the maximum tolerated, failed to alter any parameter, indicating that the very young animal differs markedly from the adult in response to that compound. The data indicate that relatively simple tests of renal function are useful in the detection of perinatally induced nephrotoxicity.

Assessment of renal concentrating ability in lithium-treated patients. Comparison of long-term dehydration with administration of a vasopressin analogue.

In patients given long-term treatment with lithium maximum urine osmolality was measured after 26 h of dehydration and after intranasal administration of desamino-8-D-arginine vasopressin (DDAVP). A high correlation was found between the results of the two tests suggesting that the DDAVP test is a suitable method of assessing renal concentrating ability in lithium-treated patients.

An investigation of the natriuretic, antidiuretic and oxytocic actions of neurohypophysial hormones and related peptides: delineation of separate mechanisms of action and assessment of molecular requirements.

The substitution of the 4-glutamine of oxytocin by a lipophilic aliphatic amino acid leucine yields [4-Leu] oxytocin which possesses natriuretic-diuretic anti-arginine-vasopressin (anti-ADH) activities. Alkyl substitutions of the beta-carbon of the 1 half-cystine of oxytocin yield a series of antioxytocin analogs which inhibit the uterotonic response to oxytocin. In this paper, the results of our further investigations on the molecular requirements for natriuretic, anti-ADH and antioxytocic activities of these peptides are reported. A total of 12 analogs of oxytocin and lysine-vasopressin (LVP) with leucine and/or beta-carbon alkyl substitutions were studied. Our findings reveal that the effect of 4-leucine substitution may not be to enhance the natriuretic activity but rather to abolish the antidiuretic activity of oxytocin. The lack of antidiuretic activity of these 4-leucine analogs makes it possible to unmask the intrinsic natriuretic activity of these peptides at the high dose level. Structure-activity correlations suggest that the oxytocin molecule may be the optimal requirement for natriuretic activity of these peptides. Substitution of 4-glutamine by lipophilic aromatic phenylalanine yields [4-Phe] oxytocin which possesses anti-ADH activity with little or no natriuretic activity. The "hybrid" antioxytocin and anti-ADH molecules, beta-carbon alkyl and 4-leucine substituted analogs did not possess enhanced antihormone activity. Although they had antioxytocic and antipressor activities, they were less potent than their respective singly alkyl substituted analogs. Furthermore, they had no demonstrable anti-ADH activity. The single alkyl substituted oxytocin and LVP also had no anti-ADH activity. It therefore appears that beta-carbon alkyl substitution had different effects on activities depending on the morphological features and the functions of the target cell. In target cells of contractile smooth muscles (uterus and vascular), the alkyl substituted analogs had no intrinsic activity but retained a relatively high receptor affinity to become effective antagonists to the natural hormone. On the other hand, in target cells of the renal tubule which are noncontractile epithelial cells, both intrinsic activity and receptor affinity were reduced or abolished. Thus none of these alkyl substituted analogs possessed more than very slight antidiuretic activity, and none had any natriuretic or anti-ADH activity.