Efficacy of a new delivery system based on solid lipid microparticles for the oral administration of the non-conventional antioxidant IAC on a diabetes mouse model.

PURPOSE: We previously showed the positive effects of the new antioxidant molecule bis(1-hydroxy-2,2,6,6-tetramethyl-4-piperidinyl)-decandioate (IAC) in reducing basal hyperglycaemia and relieving glucose intolerance in a diabetes model. However, the chemical properties of IAC did not allow an efficient oral administration, thus representing the main failing of that study. Here, we tested the effect of a new oral delivery system based on solid lipid microparticles (SLMs) in a diabetes mouse model. METHODS: The diabetes model was induced in C57B1/6J mice using streptozotocin and nicotinamide. Only the animals that overcame the glycaemic threshold of 180 mg/dL were enrolled in the study. Diabetic animals were then randomly assigned to 4 groups (n = 9) and treated once a day for 5 consecutive weeks with IAC (50, 100, and 150 mg/kg b.w.). The control group was composed of (n = 7) healthy mice that received only the vehicle. Glucose level was weekly monitored during the treatment period and up to 3 weeks after the suspension of the treatment. Glucose tolerance and insulin-resistance test were carried out. RESULTS: Our results showed that SLMs maintained the IAC effect in reducing basal hyperglycaemia as well as improving the insulin sensitivity and glucose tolerance. CONCLUSION: The present study confirms that SLMs are promising drug carriers, which allow the oral administration of IAC ensuring its therapeutic efficacy. The concrete possibility to administer IAC per os represents a significant breakthrough in the putative consideration of this multi-radical scavenger in the diabetes therapeutic approach.

The effect of polymer coatings on physicochemical properties of spray-dried liposomes for nasal delivery of BSA.

This work describes the development of spray dried polymer coated liposomes composed of soy phosphatidylcholine (SPC) and phospholipid dimyristoyl phosphatidylglycerol (DMPG) coated with alginate, chitosan or trimethyl chitosan (TMC), that are able to penetrate through the nasal mucosa and offer enhanced penetration over uncoated liposomes when delivered as a dry powder. All the liposome formulations, loaded with BSA as model antigen, were spray-dried to obtain powder size and liposome size in a suitable range for nasal delivery. Although coating resulted in some reduction in encapsulation efficiency, levels were still maintained between 60% and 69% and the structural integrity of the entrapped protein and its release characteristics were maintained. Coating with TMC gave the best product characteristics in terms of entrapment efficiency, glass transition (T(g)) and mucoadhesive strength, while penetration of nasal mucosal tissue was very encouraging when these liposomes were administered as dispersions although improved results were observed for the dry powders.

A new approach to enhance oral bioavailability of Silybum Marianum dry extract: association of mechanochemical activation and spray congealing.

The aim of the work was to produce a delivery system for Silybum Marianum dry extract with enhanced oral bioavailability by combining two technologies (mechanochemical activation and spray congealing). Initially, the active was coground with sodium croscarmellose in a planetary mill in order to reach an activated state more prone to dissolution. DSC, XRD, FT-IR and LD analyses showed the formation of nanosized particles of dry extract, with reduced degree of crystallinity of the main crystalline flavolignans (silybine A and B). Then, microparticles containing the activated coground and, as comparison, the corresponding physical mixture of extract and polymer and the dry extract alone were produced by spray congealing technology using Gelucire(®) 50/13 as a hydrophilic low m.p. carrier. Microparticles containing the activated coground were produced spherical in shape, achieved satisfactory yield and high encapsulation efficiency. These microparticles, in addition to a favourable in vitro solubilisation kinetic, in a preliminary in vivo study in five rats demonstrated their ability to improve very significantly the oral bioavailability of the main flavolignans of Silybum Marianum dry extract (silybin A and B). These results suggested that the association of mechanochemical activation and spray congealing could be considered an innovative and very useful approach to the oral delivery of Silybum Marianum. Furthermore, for the first time the possibility of successfully applying the spray congealing technology for the preparation of a herbal drug delivery system was shown.

Poloxamer 407 microspheres for orotransmucosal drug delivery. Part I: formulation, manufacturing and characterization.

The two-part article aimed to investigate poloxamer 407-based microspheres as a novel platform for enhancing and controlling the delivery of atenolol across the oromucosal tissue. In the Part I of the work, atenolol-loaded poloxamers 407 microparticles were prepared by the solvent free spray congealing technology. This approach was feasible upon the high viscosity of the systems allowing for high loaded (20% w/w) non-aggregated microspheres. Several formulations were studied and the results demonstrated that the drug release patterns, solubility data, mucoadhesion to buccal tissue and gelling properties in saliva could be modified by adding different amount of an amphiphilic polymer-lipid excipient (Gelucire(®) 50/13) to poloxamer 407. Particularly, microspheres based only on poloxamer 407 exhibited very high solubility, mucoadhesive strength and gelling behaviour. To assess their potential as matrix for buccal application, the gelling property and the drug release from tablets obtained from direct compression of the microparticles were further evaluated. The microspheres were then characterized by differential scanning calorimetry, X-ray powder diffraction and Fourier transform-infrared spectra analysis. No solid state modifications and chemical interactions were detectable in the microspheres after manufacturing and during storage, suggesting their stability and use as orotransmucosal delivery systems.

Poloxamer 407 microspheres for orotransmucosal drug delivery. Part II: In vitro/in vivo evaluation.

Aim of this research was to evaluate novel microspheres based on poloxamer 407, alone or in mixture with Gelucire(®) 50/13, as possible buccal delivery system for atenolol (AT). The microspheres have been prepared by spray congealing and investigated to assess AT in vitro delivery through cellulose membranes and ex vivo permeation using porcine buccal mucosa. The microparticles were tested as such or directly compacted to obtain tablets. For comparison the physical mixtures, tablets of the physical mixtures and an AT solution were examined. Finally, the microparticles were sublingually administered in rabbits to evaluate AT pharmacokinetics compared to a market oral tablet (reference). The AT release from microspheres through the synthetic membrane was delayed with respect to the drug solution, more markedly when microparticles contained poloxamer as unique adjuvant; this formulation enhanced AT transmucosal permeation. The enhancement effect of poloxamer was confirmed by the permeation experiments on the corresponding physical mixture. Tabletting hindered both release through cellulose membranes and transmucosal permeation of drug. In vivo studies revealed that the absolute bioavailability of microsphere formulations was higher than that of reference in spite of a lower dosage of drug, suggesting a possible dose reduction by AT microparticles orotransmucosal administration.

Empirical kinetic model of propafenone release from Hot Air Coating microparticles.

Lipid microparticles, containing 30% and 50% (w/w) propafenone hydrochloride as the active molecule and cetearyl alcohol and Pluronic F68 as excipients, were prepared by Hot Air Coating (HAC). The aim of the work was to identify the kinetics and the mechanism of the drug release process from these microparticulate systems. The application of the Weibull model to the release data from each single fraction of microparticles suggests that a diffusive mechanism governs drug release from microparticles. Thus, we proposed and applied a release kinetic model to the experimental data that takes into account the diffusion as the predominantly mechanism of drug release. The model proposed is a modified version of the exponential equation in which the product of the apparent release rate constant K, specific for each drug/excipient mixture, and the area-to-volume ratio of particles was used. The K values of single fractions of HAC microparticles (coded K(fr)) are very similar to those of the mixtures of particles obtained from the process (coded K(pool)). Using the K(pool) constants, the release behaviour of ensembles of different size microparticles of well-known composition was predicted. The strength of the model was proved by the good fitting of the experimental release data versus those predicted (R(2)> or =0.997).

Characterization of nifedipine microparticles prepared by hot air coating technique.

In the present work, the Hot Air Coating (HAC) technique was used to prepare microparticulate systems containing nifedipine. Binary mixtures constituting of nifedipine and cetearyl alcohol (CA) in different proportions (30:70, 50:50, 70:30) were studied: they were homogenized by mixing or milling before spray treatment and successively subjected to a coating procedure with the HAC apparatus fed with air at 120 degrees C under a pressure of 4.5 atm. Morphology, entrapment efficiency, drug stability, thermal behaviour and the drug dissolution profile of HAC-treated and non-treated materials were examined and compared. The HAC products show the possession of physical and physico-chemical properties and dissolution behaviour different from those of the initial physical mixtures. The operative conditions employed in the spray process allow the obtaining of microparticles containing relevant percentages of the drug (at least up to 50%). Moreover, the experimental results give evidence that the milling pre-treatment of mixtures, unlike mixing, has significant effects on the properties of the lipid-coated microparticles.

Ultrasound-compacted and spray-congealed indomethacin/polyethyleneglycol systems.

The product obtained by ultrasound (US)-assisted compaction was compared with a solid dispersion for systems containing polyethyleneglycols (PEGs) of different molecular weights and indomethacin (IMC), at the weight ratio 9:1, obtained by traditional melting and followed by a new US-assisted spray-congealing technique. US-discharge during compaction affects crystallinity of both IMC and PEG: pure IMC changes to an amorphous form and, when in mixture with PEG, partially dissolves in the excipient: this causes an increase of the dissolution rate of the drug. Differential scanning calorimetry (DSC) thermograms do not reveal any endothermic peak associated with the melting of the drug, while X-ray diffractograms show a loss of crystallinity of both IMC and PEG in the US-compacted granules. The extent of a back-crystallisation, which reduces the dissolution rate, as a function of the ageing of the material, depends on the type of the selected PEG. When a molten IMC/PEG mixture was transformed into microspheres by an US-assisted spray-congealing technique, the behaviour at dissolution almost recalls that of US-compacted granulates and some differences are briefly discussed.

Preparation and characterization by morphological analysis of diclofenac/PEG 4000 granules obtained using three different techniques.

The steam granulation is a new wet granulation technique, which involves the use of steam water instead of traditional liquid water as granulation liquid. The aim of this work was to evaluate the possibility of using this new technique to prepare diclofenac-polyethylene glycol 4000 accelerated-release granules. Steam granules were prepared in a laboratory scale high-shear mixer, and their properties were then compared to those of granules, having the same composition, obtained by traditional granulation techniques (wet and melt granulation). The results showed that, selecting the proper process parameters, it was possible to obtain granules using all the three methods; however, the total process time was significantly shorter for steam granulation (30 min) in comparison to traditional wet granulation (70 min), due to the lower amount of used water. The morphological characterization of steam, water and melt granules, performed by scanning electron microscopy (SEM) and image analysis, revealed that steam granules had a more spherical shape and a larger surface area with respect to water and melt ones, suggesting a possible difference in dissolution behavior. Moreover, differential scanning calorimetry (DSC) and X-ray powder diffraction analysis evidenced the transformation of the drug from its originally crystalline form into the amorphous one. Finally, the in vitro dissolution tests showed an increased dissolution rate of the drug from the granules (in particular steam granules) in comparison to pure drug and physical mixture. In conclusion, the results of this study suggested that the steam granulation technique could be considered an interesting alternative to traditional wet granulation to improve the dissolution rate of diclofenac.

Equal levels of blood pressure control in ESRD patients receiving high-efficiency hemodialysis and conventional hemodialysis.

The present study compared the status of hypertension and adequacy of blood pressure control in 73 end-stage renal disease (ESRD) patients treated with four different modalities of hemodialysis, namely, conventional hemodialysis (CHD) with cuprophan 1.1 m2 at a blood flow rate of 300 mL/min, high-efficiency hemodialysis (HED) with cuprophan 1.6 m2 at a blood flow rate of 450 to 500 mL/min, high-flux hemodialysis (HFD) with F80 polysulfone 1.8 m2 at a blood flow rate 500 mL/min, and high-flux hemodiafiltration (HDF) with F80 2 x 1.8 m2 in series at a blood flow rate of 600 to 650 mL/min. Thirty of the 73 patients (41%) were receiving one or more antihypertensive agents to control their hypertension. The percentage of patients taking antihypertensive medication was less in the groups treated with HED, HFD, and HDF compared with the CHD group: 38%, 39%, and 39%, respectively, in the HED, HFD, and HDF groups versus 56% in the CHD group. Control of systolic and diastolic hypertension was achieved in a higher percentage of patients treated with HED, HFD, and HDF compared with patients treated with CHD. Sixty-two percent of HED, 58% of HFD, and 61% of HDF patients compared with 44% of CHD patients had systolic blood pressure less than 150 mm Hg, whereas 77% of HED, 76% of HFD, and 78% of HDF patients compared 56% of CHD patients had diastolic blood pressure less than 90 mm Hg. However, the differences in the use of antihypertensive medication and control rates of hypertension did not reach statistical significance. The average blood pressure of all patients was 144/89 mm Hg; this did not differ significantly between the four groups. There also were no significant differences in etiology of ESRD, hematocrit, biochemical data, as well as use and dose of recombinant human erythropoietin between the four groups. Compared with the CHD patients, the average treatment times with high-efficiency treatments were shorter, with HDF patients showing the shortest mean treatment time of 157+/-41 minutes per hemodialysis session. The mean Kt/V was higher in the groups treated with HED, HFD, or HDF (1.31+/-0.3, 1.30+/-0.4, and 1.43+/-0.3, respectively) than in the CHD group (1.12+/-0.3; P < 0.05). Interdialytic weight gain also did not differ among the four groups. There was no correlation between predialysis mean arterial pressure and either treatment time (r = 0.04, P = NS), Kt/V (r = 0.03, P = NS), ultrafiltration rate (r = 0.06, P = NS), or interdialytic weight gain (r= -0.08, P = NS). There also was no significant association between Kt/V and use of antihypertensive medications (chi-square = 1.76, P = NS). There was, however, a significant positive correlation between interdialytic weight gain and treatment time (r = 0.33, P < 0.01). We conclude that the use of short dialysis sessions with efficient hemodialysis treatments, namely, HFD and HDF, was associated with similar levels of blood pressure control in ESRD patients.

La glucosa en conjunto con péptidos derivados de cininógenos podrían actuar desde el aparato digestivo como bloqueadores de la acción diurética-natriurética del péptido natriurético auricular / Glucose in conjunction with peptides derived from kininogens might act from digestive tract as blockers of ANP mediated diuresis-natriuresis

This paper describes long term research efforts wich have lead: 1) to the identification of peptides present in pepsanurin, a peptidic fraction obtained by pepsin hydrolisis of plasma globulins that inhibits the renal excretory action of atrial natriuretic peptide (ANP) and 2) to the discovery of an unexpected role of glucose, as a requisite, for these inhibitory effects. The active peptides identified in pepsanurin are derived from plasma kininogens, substrates of the kallikrein-kinin system. Pro-kinins of 15, 16 and 18 aminoacids, and bradykinin itself, block ANP-induced diuresis and natriuresis when injected iv, ip or into, the duodenal lumen of anesthetized rats in picomol doses. Furthermore, a novel 20 aminoacids fragment derived from kininogen dominium-1, named PU-D1, is the most potent and longer lasting blocker of ANP renal effects. The anti-ANP effects of those peptides are prevented by B2- kinin receptor antagonists. The inhibition of ANP by kinins and PU-D1 was evident only in rats infused with isotonic glucose; whereas the excretory effect of ANP was not affected in fasted rats not infused, or infused with saline. These findings provide evidence that glucose facilitates liquid retention through a kinin-mediated inhibition of ANP excretory action that may be related to the prandial cycle

Hormonas vasodilatadoras en la insuficiencia cardíaca crónica: efecto de la inhibición de la enzima convertidora de angiotensina / Vasodilator hormones in chronic heart failure: effect of the inhibition of angiotensine converting enzyme

To evaluate the chronic effect of enalapril, in addition to digitalis and diuretics, in patients with chronic heart failure, nine patients with an idopathic dilated cardiomyopathy (8 males, aged 48 to 76 years old) under treatment with digitalis and diuretics, received enalapril 20 mg bid during eigth weeks. Before and after this treatment period resting left ventricular ejection fraction, functional class, plasma levels of atrial natriuretic factor and bradykinins (BK) and urinary excretion of kalikreins (BK) and prostaglandins E2 (PGE2) were measured. After enalapril therapy, there was a significant increase in maximal O2 consumption (14.8ñ1.2 to 18.6ñ1.5 ml/kg/min, p<0.05) and radionuclide LV ejection fraction (27.4ñ1.1 to 31.4ñ0.9 percent p<0.05). This was associated with a significant decrease in plasma ANP levels (559ñ158 to 178ñ54.8 pg/ml) and UK (391ñ112 to 243ñ92 Cu/24 h). The decrease in ANP levels, which is a well known marker of prognosis in CHF, could contribute to explain the sustained clinical benefits observed with ACE inhibitors in patients with CHF

Control of hypertension is better during hemodialysis than during continuous ambulatory peritoneal dialysis in ESRD patients.

This study compared the status and adequacy of blood pressure (BP) control in 21 ESRD patients treated with HD and CAPD at different time periods. Patients were considered to be hypertensive it they were receiving antihypertensive medications during the study period. During HD, 9 of the 21 patients (43%) required antihypertensive drugs to control their hypertension; whereas, during CAPD, the number of patients taking antihypertensive drugs increased to 15 (71%) (p < 0.05). Adequate control of hypertension (systolic BP < 150 mmHg and/or diastolic BP < 90 mmHg) was achieved in 17 patients (81%) during HD compared to 11 patients (52%) during CAPD (p < 0.05). Average ultrafiltration rate was 1.28 +/- 0.1 l/day during HD and 1.30 +/- 0.2 l/day during CAPD (p = NS). Mean Kt/V during HD was 1.24 +/- 0.1; whereas, mean weekly Kt/V during CAPD was 1.81 +/- 0.2. There were no significant differences in hematocrit or usage of recombinant human erythropoietin (rHuEPo) between the two treatment modalities. However, the weekly dose of rHuEpo was higher during HD than during CAPD (p < 0.05). Mean body weight was significantly higher (p < 0.01) and serum albumin was lower (p < 0.05) during CAPD than during HD in the same group of patients. We conclude that hypertension appears to be controlled better by HD than by CAPD in ESRD patients. The gain in body weight observed with CAPD treatment may reflect an increase in total body fluid volume which may partly explain why hypertension is less adequately controlled during CAPD than during HD treatment.

Selective removal of plasma low density lipoprotein with the HELP system: biweekly versus weekly therapy.

PURPOSE: Biweekly (once every 2 weeks) heparin-induced extracorporeal low-density lipoprotein (LDL) precipitation (HELP) therapy was evaluated for safety and efficacy in selectively reducing LDL cholesterol levels compared with weekly HELP therapy. PATIENTS AND METHODS: Biweekly treatments were given to high-risk, diet/drug resistant hypercholesterolemic patients (n = 23) after 6 months of weekly HELP therapy. Lipids, lipoprotein cholesterol, apolipoproteins A-I and B, and fibrinogen were measured on plasma samples before and after treatment. RESULTS: Mean plasma volume treated was 2.8 l and mean treatment duration 1.7 h. Therapy complications were minimal. In 98% of 268 biweekly HELP treatments, LDL cholesterol levels were reduced by > 30%. For patients completing 6 months of biweekly therapy following 6 months' weekly therapy (n = 23), mean LDL cholesterol levels were reduced 138.5 mg/dl (111.2 mg/dl weekly) with a time-averaged decrease from mean pre-apheresis levels of 33% for biweekly therapy (39% weekly). Mean total cholesterol (161.2 mg/dl biweekly versus 132.9 weekly) and apolipoprotein B (104.6 mg/dl versus 92.6) levels were also reduced with each treatment. Mean HDL cholesterol was reduced only 6.1 mg/dl (6.3 mg/dl weekly). CONCLUSIONS: Biweekly HELP treatments can safely reduce LDL cholesterol levels as consistently as weekly HELP treatments. However, the higher pre-treatment LDL cholesterol levels with biweekly treatments may produce less therapeutic benefit than with weekly therapy.

Epidemiology of hepatitis C virus infection in patients with renal disease.

This study was carried out to determine the prevalence of hepatitis C virus (HCV) antibodies and the epidemiologic factors associated with HCV infection in patients with chronic renal failure before the onset of ESRD. Sex, age, type of renal disease, level of renal function, and history of blood transfusions and invasive procedures were analyzed in 226 patients with renal disease, compared with a population of 1,244 normal subjects and 124 patients with impaired immunity (patients having autoimmune diseases and receiving chemotherapy treatment). Eighteen seropositive patients with renal disease (prevalence, 7.9%) were found, which was significantly higher than the prevalence in the normal population (1.03% in blood donors, 0.98% in pregnant women; P < 0.001, chi 2). There was no significant association of sex, number of blood transfusions, or history of invasive procedures with the presence of HCV antibodies. The prevalence of HCV antibodies was higher (16.6%) in patients with glomerulonephritis compared with patients diagnosed with interstitial nephritis, pyelonephritis, nephrosclerosis, diabetes mellitus, polycystic kidney, and miscellaneous renal diseases (P < 0.01, chi 2). There was a higher prevalence of HCV antibodies in patients with creatinine clearance lower than 30 mL/min (13%) compared with patients with creatinine clearance higher than 30 mL/min (2.7%) (P < 0.01, chi 2). These data suggest that HCV infection may be associated with the pathogenesis of glomerulonephritis. Alternatively, glomerulonephritis or severe renal insufficiency may increase the likelihood of HCV infection.

El proceso digestivo y la regulación de la función excretora renal: pepsanuria y procininas inhibidoras de la acción diurética del péptido natriurético auricular / Digestive process and regulation of renal excretory function: pepsanurin and prokinin inhibitors of diuretic action of atrial natriuretic peptide

In order to clarify the blunting effect of peptides released by pepsin from blood plasma on ANP diuretic action, 2 prokinins designated PU-16 were tested. Both of them were able to inhibit in nanomolar doses the diuretic-saluretic action of 0.5 ug i.v. bolus of ANP given to anesthetized rats either by intravenous route or introduced in the duodenal lumen. PU-16 in doses of 0.5 ug and 1 ug were able to reduce in 72 and 96.5 per cent respectively the natriuresis induced bu 0.5 ug intravenous bolus of ANP. The data support the hypothesis that prokinins liberated in the digestive tract, could be physiological factors involved in hydrosaline homeostasis, moderating the ANP mediated increase of water, Na and K excretion during digestion

Recurrent hematuria in a patient with a history of anaphylactic reaction to radiographic contrast.

Hematuria is a relatively common problem, but its evaluation can be complicated. One must pay attention to the patient's symptoms and extrarenal manifestations of disease to identify the etiology efficiently. We present the case of a patient who narrated a fascinating past medical history and a dramatic presentation of hematuria that had been exhaustively evaluated at another hospital. During a prolonged and involved stay at our institution, the etiology of the hematuria remained enigmatic after extensive radiologic and invasive investigations that led to internally inconsistent findings, until an unusual diagnosis was entertained.

Weekly treatment of diet/drug-resistant hypercholesterolemia with the heparin-induced extracorporeal low-density lipoprotein precipitation (HELP) system by selective plasma low-density lipoprotein removal.

Heparin-induced extracorporeal low-density lipoprotein (LDL) precipitation (HELP) weekly therapy was evaluated for safety and efficacy in selectively reducing LDL cholesterol levels. Weekly treatments (25) were given to high-risk hypercholesterolemic patients (n = 33) with screening LDL cholesterol levels > 160 mg/dl despite prior diet and drug therapy. Lipids, lipoprotein cholesterol, apolipoproteins A-l and B, and fibrinogen were measured on plasma samples before and after treatment. Mean plasma volume treated was 2.66 liters and mean treatment duration 1.7 hours. Therapy complications were infrequent and were primarily vascular access problems or hypotension. Treatment goals were > 30% LDL cholesterol reduction with each treatment. In 98% of 686 HELP treatments, LDL cholesterol levels were reduced > or = 30%. Mean LDL cholesterol levels were reduced 111.0 mg/dl (54%) with a time-averaged decrease of 39% over a 25-week course. Mean HDL cholesterol was reduced only 6.2 mg/dl (15%). Total cholesterol (134.4 mg/dl; 47% decrease) and apolipoprotein B (88.7 mg/dl; 53% decrease) levels were also reduced. Fibrinogen decreased 158.2 mg/dl (58%) without bleeding complications. HELP therapy can safely and selectively remove plasma LDL cholesterol, producing consistent reductions in LDL cholesterol, total cholesterol and apolipoprotein B levels.

Pepsanurina en la insuficiencia cardíaca congestiva / Pepsanurin in congestive heart failure

We have identified a plasmatic substance, "pepsanurin" (PU) obtained by pepsin hydrolysis which inhibits the renal effects of the atrial natriuretic factor (ANF). To investigate whether patients with congestive heart failure (CHF) have increased plasma levels of PU we prepared PU from 10 patients with CHF class IV (NYHA), 9 patients with CHF class II or III and 16 healthy controls. Anesthetized rats were used to test the effects of ANF, 0.5 ug/100 g body weight i.v., before and following the intraperitoneal injection of 0.5 ml of PU. The inhibition of the diuretic and natriuretic effects of ANF was 40.9 ñ 11.9% and 49.8 ñ 12% respectively for control subjects. Corresponding figures for clas CHF patients were 62.3 ñ 3.1% and 73.8 ñ 3.5% (p < 0.02) and for class II-III patients 39.2 ñ 7.0% and 53.1 ñ 8.2% (NS). Accordingly, an increased capacity to generate PU may underlie the decreased sensitivity to ANF in patients with advanced CHF