Gastrokine 1 expression in patients with and without Helicobacter pylori infection.

BACKGROUND: To understand the molecular changes underlying Helicobacter pylori-related gastric diseases is mandatory to prevent gastric cancer. Proteomic technology is providing a rapid expansion of the basic knowledge, particularly in the discovery of new biomarkers involved in the tumourigenesis. AIM: To characterise changes in protein expression level of the gastric mucosa in H. pylori-infected patients. METHODS: The population enrolled comprised 41 dyspeptic patients. Proteins extracted from gastric mucosal specimens were analysed by 2-dimensional electrophoresis, sequenced by MALDI-TOF and identified by Edman's degradation. RESULTS: Twenty-one out of 41 patients had H. pylori infection of whom 17 had anti-CagA IgG antibodies. Several proteins were identified, of which Rho guanosine diphosphatase dissociation inhibitor alpha and heat shock protein 27 increased and glutathione transferase and antrum mucosa protein-18 decreased in H. pylori-positive in respect to H. pylori-negative patients. Interestingly, antrum mucosa protein-18, currently referred as gastrokine-1, showed two isoforms differing in the first N-terminal amino acid residue. Both gastrokine-1 isoforms were observed in the H. pylori-negative group whereas a lower expression or even absence of the gastrokine-1 basic isoform was found in a subgroup (7/21) of H. pylori-positive patients with moderate-severe gastritis. CONCLUSION: Our study demonstrated the presence of gastrokine-1 isoforms of which the basic isoform was reduced in a subset of patients with H. pylori infection.

The purification and characterization of alpha-L-fucosidase from the hepatopancreas of Octopus vulgaris.

We have isolated and purified, by affinity chromatography with Agarose-epsilon-amino-caproyl-fucosamine, an alpha-L-fucosidase [alpha-L-fucoside fucohydrolase EC 3.2.1.51] from the hepatopancreas of Octopus vulgaris. In the purified fraction only fucosidase activity could be detected. However, two protein bands, one major (about 95 per cent) and one minor (about 5 per cent), were evident on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Isoelectric focusing also revealed two activities, pI 8.1 (major) and pI 7.3 (minor). Under denaturing conditions the molecular weight of the major band was estimated to be 52,000 while that of the minor one was 43,000. Only one major activity peak with an apparent molecular weight of 70,000--75,000 was detected by gel filtration chromatography. The enzyme has two optimal pH values, and the relative activities are temperature-dependent; one optimum is at pH 5.5 +/- 0.2 and the other at pH 3.0 +/- 0.2. We found that the enzyme has a maximum activity at about 70 degrees C, but 50 per cent of the enzyme was inactivated at 70 degrees C after 5 min. The purified enzyme, using p-nitrophenyl-L-fucoside as substrate, has a specific activity of 38.9 units/mg of protein, Km of 3.58 x 10(-4) M and Vmax of 65 mumol/min/mg of protein. alpha-L-Fucose acts as a competitive inhibitor, with a K1 of 1.2 x 10(-3) M. alpha-L-Fucosidase released radioactive fucose from cellular glycopeptides, but no detectable free fucose was released fom 5 natural substrates.

[Tag 72: a new tumor-associated antigen identified by a monoclonal antibody]. / Tag 72: un nuovo antigene tumore associato riconosciuto da un anticorpo monoclonale.

In order to evaluate the usefulness of Tag 72--tumor associated antigen assay--in gastroenterology, we have studied with Ca 72-4 radioimmunoassay (Centocor) 551 patients suffering benign (233) and neoplastic (318) gastrointestinal diseases and 205 normal controls. The cut-off point was fixed at 6 U/ml. Only in gastric cancers, the Tag 72 assay, with the proposed method, provide additional information in this pathology (sensitivity 30%, specificity 98.7%). The most striking observation to be made from the current study is a poor sensitivity of the test for gastrointestinal cancers, but rather the excellent specificity of the Ca 72-4 IRMA with respect to benign gastrointestinal diseases. The sensitivity of Ca 72-4 assay, vs Ca 19-9 and CEA, for the same diseases, is less, but specificity is better.

[Scintigraphy using indium-111-oxine as an aid to transrectal echography in the diagnosis of perianal abscess]. / La scintigrafia con l'utilizzo di indio 111-oxina quale ausilio dell'ecografia transrettale nella diagnostica della patologia ascessuale perianale.

The paper describes the authors experience relating to the use of indium-111-oxine scintigraphy as an aid to transrectal echography in the diagnosis of difficult anal fistulas. This method has proved useful in locating otherwise undetected accumulations and in controlling the outcome of operations with a "slow resolution" of the surgical wound. The marker showed a good level of resolution in that, as already shown in the case of chronic inflammatory diseases, marked leukocytes are prevalently located on the site of infection.

Multislice CT with single-phase technique in patients with suspected pancreatic cancer.

PURPOSE: The purpose of this study was to evaluate the role of multislice computed tomography (MSCT) with a single-phase technique in patients with suspected pancreatic cancer (PC). MATERIALS AND METHODS: Seventy-eight patients underwent MSCT with the following technical parameters: collimation: 4x1 mm; pitch 1; 120 kVp; 260 mAs. The pre-contrast scan was followed by a single acquisition phase in the caudocranial direction from the inferior hepatic margin to the diaphragm with a 60-s delay after IV administration of 150 ml of iodinated contrast material at a rate of 3 ml/s. Two radiologists assessed the single images independently. Receiver operating characteristics (ROC) curves were obtained for each of the two observers. RESULTS: The final diagnosis was pancreatic cancer in 46 cases and chronic pancreatitis in 32 cases. Areas under the curve (AZ) for diagnosis and evaluation of disease resectability were 0.97 and 0.93 for the first observer (p=ns), and 0.97 and 0.90 for the second observer (p=ns). The mean difference in tissue attenuation values between the cancer and normal pancreas was 72 +/- 3 Hounsfield units (HU). No statistically significant differences were observed in the degree of opacification between the peripancreatic arteries and veins. CONCLUSIONS: MSCT with a single-phase technique is an accurate and reproducible method for diagnosis and evaluation of disease resectability in patients with suspected PC, ensuring optimal tumour-to-pancreas contrast and maximal opacification of the main peripancreatic arterial and venous structures.

Estimation of chromium-51 ethylene diamine tetra-acetic acid plasma clearance: a comparative assessment of simplified techniques.

Chromium-51 ethylene diamine tetra-acetic acid (51Cr-EDTA) total plasma clearance was evaluated using a multi-sample method (i.e. 12 blood samples) as the reference compared with several simplified methods which necessitated only one or few blood samples. The following 5 methods were evaluated: terminal slope-intercept method with 3 blood samples, simplified method of Bröchner-Mortensen and 3 single-sample methods (Constable, Christensen and Groth, Tauxe). Linear regression analysis was performed. Standard error of estimate, bias and imprecision of different methods were evaluated. For 51Cr-EDTA total plasma clearance greater than 30 ml.min-1, the results which most approximated the reference source were obtained by the Christensen and Groth method at a sampling time of 300 min (inaccuracy of 4.9%). For clearances between 10 and 30 ml.min-1, single-sample methods failed to give reliable results. Terminal slope-intercept and Bröchner-Mortensen methods were better, with inaccuracies of 17.7% and 16.9%, respectively. Although sampling times at 180, 240 and 300 min are time-consuming for patients, 51Cr-EDTA total plasma clearance can be accurately calculated for values greater than 10 ml.min-1 using the Bröchner-Mortensen method. In patients with clearance greater than 30 ml.min-1, single-sample techniques provide a good alternative to the multi-sample method; the choice of the method to be used depends on the degree of accuracy required.

[The role of early protein restriction in patients with initial renal insufficiency]. / Il ruolo di una precoce restrizione proteica in pazienti affetti da insufficienza renale iniziale.

The effect of early protein restriction (0.6 g:kg/p.i./die) in patients suffering from initial kidney failure for a period of two years has been studied. The hypoprotein diet proved effective in slowing development of kidney damage in so far as a stabilization was observed in renal function parameters during the hypoprotein diet period compared to the non-diet period.

Angiotensin II local hyperreactivity in the progression of IgA nephropathy.

Immunologic and hemodynamic factors are likely to work in synergism in the progression of immunoglobulin A nephropathy (IgAN) toward sclerosis. The local activation of the renin-angiotensin system may be one the most relevant mechanisms. We investigated the hemodynamic effects of the acute administration of angiotensin-converting enzyme inhibitor (ACEI) (captopril 50 mg). The glomerular filtration rate (GFR) and the effective renal plasma flow (ERPF) were measured by 51Cr-EDTA and 125I hippurate clearances. The correspondent filtration fractions (FFs) in basal conditions and after administration of ACEI were calculated, then the changes in FF (delta FF and % delta FF) were determined. We studied 27 IgAN patients. Eighteen patients had normal renal function (GFR, 112 +/- 19 mL/min/1.73 m2) and nine had moderate renal impairment (GFR, 54 +/- 13 mL/min/1.73 m2). Sixteen patients had proteinuria > or = 0.5 g/d. In addition, 12 glomerulonephritis control cases and eight healthy subjects were investigated. After the administration of ACEI in healthy subjects we observed slight modifications in the GFR, a significant increase in the ERPF (P < 0.005), and a significant decrease in FF (P < 0.04). Similarly, in IgAN patients with normal renal function the GFR increased slightly, the ERPF increased significantly (P < 0.01), and there was a decrease in FF (P < 0.01). The delta FF and % delta FF values were not significantly different from those found in the controls. In patients with initial renal failure GFR remained unchanged, ERPF increased significantly (P < 0.005), and FF significantly decreased (P < 0.004). However, the changes in delta FF and % delta FF were significantly greater than those found in healthy controls (P < 0.01) and in IgAN patients with normal renal function (P < 0.001). IgAN patients with proteinuria levels > or = 0.5 g/d showed greater changes in delta FF and % delta FF after the administration of ACEI than patients with proteinuria levels lower than 0.5 g/d (P < 0.003 and P < 0.04, respectively) or proteinuric control cases (P < 0.05 and P < 0.01, respectively). This different response in proteinuric and nonproteinuric patients was evident even when the analysis was limited to the subgroup of IgAN patients with normal renal function. The decrease in FF consequent to an increase in the ERPF after the administration of ACEI suggests a local hyperactivity of the renin-angiotensin system in some cases of IgAN.(ABSTRACT TRUNCATED AT 400 WORDS)

Removal systems of immunoglobulin A and immunoglobulin A containing complexes in IgA nephropathy and cirrhosis patients. The role of asialoglycoprotein receptors.

BACKGROUND: Whereas the complex removal routes hypothesized for IgA containing immune complexes (IC) and macromolecules can be adequately analyzed by a recently proposed IgA1-IgG aggregate probe (Lab Invest, 66: 86-95), the relative significance of the asialoglycoprotein receptors in IgAIC clearance is still uncertain. EXPERIMENTAL DESIGN: The removal kinetics of 99mTc diethylenetriamine-pentaacetic acid-conjugated asialo alpha 1 acid glycoprotein (AAGP) and 123I-labeled IgA1-IgG aggregate were analyzed in 11 cirrhosis patients and 13 IgAN patients of comparable age. RESULTS: IgA1-IgG aggregate mean plasma clearance rate was delayed in IgA neuropathy (IgAN) patients (slope 0.038 minutes-1, range 0.027 to 0.053) compared with normals (0.047 minutes-1, range 0.038 to 0.053, p = 0.05). The liver was the main organ involved in the IgA1-IgG removal. When compared with normals, (34.3 minutes, range 29.8 to 42.2), the liver mean transit time (MTT) was significantly (p < 0.02) prolonged in IgAN patients (41.3 minutes, 33.6 to 52.3). Participation of spleen in clearance was observed in some patients and was almost invariably concurrent with normal clearance parameters. Conversely, 9 out of 11 cirrhosis patients had a remarkable splenic uptake, but the blood clearance rate was invariably delayed (0.022 minutes-1, 0.014 to 0.028, p < 0.003) and liver MTT extremely prolonged (122.4 minutes, 52.4 to 400, p < 0.003). In IgAN patients with delayed clearance of the IgA1-IgG aggregate, a distinct trend of progression towards renal failure was noted. AAGP clearance was also delayed in cirrhosis patients: slope = 0.166 minutes-1, 0.108 to 0.247, p = 0.05 as compared with both normals (0.230, 0.173 to 0.289) and IgAN patients (0.250, 0.184 to 0.254). Liver MTT in cirrhosis patients was extremely prolonged: 240.6 minutes, 132.5 to 400 minutes, p < 0.007 compared with both normals (90.0 minutes, 82.7 to 96.6) and IgA patients (92.2 minutes, 70.3 to 107.1). AAGP clearance parameters in normals and IgAN patients were not statistically different. MTT values of AAGP and IgA1-IgG aggregate were strictly related (p = 0.008), suggesting that asialoglycoprotein receptors are partially involved in the clearance of the IgA1-IgG aggregate probe. CONCLUSIONS: Some patients with IgAN have a prolonged circulation of an IgAIC miming probe, probably due to an impaired macrophage function. Other possibilities of prolonged circulation of IgAIC in these patients should imply an abnormal IgA glycosylation pattern that allows IC to escape from an effective asialoglycoprotein receptor system. In cirrhosis patients, all of the removal routes of IgA and IgA containing IC are greatly altered suggesting a causative role in the development of an associated, often clinically inapparent, glomerular disease.

The fate of aggregated immunoglobulin A injected in IgA nephropathy patients and healthy controls.

Organ uptake of IgA-containing immunologically active material was studied in humans by intravenous (IV) injection of 131I-labeled heat-aggregated human secretory IgA (HAS-IgA) in nine patients affected by primary IgA nephropathy and 10 normal volunteers. Aggregated secretory IgA was found to be removed almost exclusively by the liver. The peak activity in liver was reached at 21.1 minutes (range, 18 to 26 minutes) in patients and 19 minutes (range, 14 to 22 minutes) in controls. The rate of increase of liver radioactivity was found to be significantly slower in patients (with a mean slope of 5.0; range, 3.4 to 7.1 v 7.6, 5.6 to 11.4; P less than 0.02). The mean liver to precordium ratio at the peak time was significantly lower in patients (mean value, 2.3; range, 1.9 to 3.1) compared with controls (mean value, 3.3; range, 2.4 to 4.0) (P less than 0.02). These data confirm the pivotal role of the liver in the removal of aggregated IgA in humans and the defective clearance capacity of this test probe in IgA nephropathy patients.

Role of platelet-activating factor in polymorphonuclear neutrophil recruitment in reperfused ischemic rabbit heart.

This study investigated the role of platelet-activating factor in the recruitment of polymorphonuclear neutrophils (PMN) in a rabbit model of cardiac ischemia and reperfusion. The accumulation of PMN was evaluated 2 and 24 hours after removal of 40 minutes of coronary occlusion by morphometric analysis and 111In-labeled PMN infiltration. The administration of two structurally unrelated platelet-activating factor-receptor antagonists (SDZ 63-675, 5 mg/kg body weight, and WEB 2170, 5 mg/kg body weight) before reperfusion significantly reduced the accumulation of PMN, as well as the hemodynamic alterations and the size of necrotic area. Two hours after reperfusion, the percentage of increase of 111In-labeled PMN in transmural central ischemic zone was significantly reduced in rabbits pretreated with SDZ 63-675 (51.4 +/- 7.9) or WEB 2170 (32.4 +/- 8.8) with respect to untreated rabbits (107.6 +/- 13.5). The morphometric analysis of myocardial sections confirmed the reduction of PMN infiltration at 2 hours and demonstrated that at 24 hours the phenomenon was even more significant. In addition, SDZ 63-675 and WEB 2170 prevented early transient bradycardia and hypotension and reduced the infarct size, judged by staining with tetrazolium at 2 and 24 hours after reperfusion, and by histological examination at 24 hours. These results suggest that platelet-activating factor is involved in the accumulation of PMN in the reperfused ischemic myocardium and contributes to the evolution of myocardial injury.

A possible role for nitric oxide in modulating the functional cyclosporine toxicity by arginine.

The renal damage consequent to cyclosporine A (CsA) administration ranges from hemodynamic alterations to irreversible chronic lesions. The initial vasoconstriction depends upon the imbalance between the various modulators of the renal vascular tone, among which the most powerful are endothelins and nitric oxide (NO). CsA could play a crucial role by inhibiting the Ca++/calmodulin-mediated activation of the constitutive NO synthase (NOS) isoform, which converts L-arginine (L-Arg) into NO and citrulline, with a 1:1 stoichiometry. To investigate the possibility of modulating CsA nephrotoxicity with L-Arg we studied six groups (G) of Lewis rats treated with daily gavage up to eight weeks: G1, CsA 40 mg/kg; G2, G1 plus L-Arg 300 mg/kg; G3, G2 plus the competitive inhibitor of NOS, NG-nitro-L-Arg (L-NNA); G4, L-Arg alone; G5, L-NNA alone; and G6, controls receiving vehicle alone. After eight weeks L-Arg treated rats were protected against the toxic effects of CsA [creatinine (Cr) values, G2, 0.62 +/- 0.05 mg/dl vs. G1, 0.99 +/- 0.16 mg/dl, P < 0.001; proteinuria (P), G2, 7.2 +/- 1.02 mg/day vs. G1, 15.1 +/- 1.9 mg/day, P < 0.01]. The administration of L-NNA abolished the protective effect of L-Arg (G3, Cr 1.23 +/- 0.16 mg/dl; P 16.9 = 2.3; P < 0.02 and P < 0.005, respectively vs. G2). The levels of Cr in G2 rats were superimposable to control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Kinetics and fate of IgA-IgG aggregates as a model of naturally occurring immune complexes in IgA nephropathy.

The characteristic granular IgA immunofluorescent pattern in the kidneys of IgA nephropathy patients is consistent with immune complex pathogenesis. The possibility of a delayed clearance of IgA-containing immune complexes from circulation in IgA nephropathy patients is still under discussion. Since pure IgA immune complexes are probably nonphlogistic, (in contrast to IgG-containing IgA immune complexes), the in vivo clearance of a mixture of heat-aggregated IgA/G purified from pooled human sera was analyzed. The test probe was efficiently labeled with 123I and the time course of radioactivity was measured by a gamma-camera. Both the liver and the spleen were found to be involved in the disappearance of IgA/G complexes. Liver accumulation, which was markedly predominant, closely approximates a gamma-variate function which allowed determination of a mean transit time of 34.37 minutes, range 29.8 to 42.2, in 8 normal and 37.54 minutes, range 30.9 to 50.7 in 17 patients (p less than 0.04). At 2 hours, segmental gut accumulation was found, which demonstrated removal by hepatobiliary system as well. Compartmental analysis in patients indicated 3 major compartments represented by vascular bed, hepatobiliary and reticuloendothelial systems (including both liver and spleen phagocytes). Blood clearance rate, representing the final result of multiorgan removal of the test probe from the blood stream, was found to be significantly delayed in IgA nephropathy patients with a slope (0.035 min-1, range 0.019 to 0.052) significantly less negative compared with controls (0.047 min-1, range 0.038 to 0.053, p less than 0.01). This test probe was able to reproduce both removal routes (macrophages cells and hepatobiliary system) hypothesized for IgA-containing immune complexes in humans.

Indium-111-labeled granulocyte head accumulation in patients with Wegener's granulomatosis.

Among the symptoms of systemic vasculitis, purulent rhinorrhea with painful sinusitis is thought to be relatively specific to Wegener's granulomatosis (WG). Sixteen patients with rapidly progressive glomerulonephritis (GN), arteritis and extensive crescents in renal biopsy were studied by head indium-111 (111In)-granulocyte scanning. They included 8 WG, 5 microscopic polyarteritis, 2 necrotizing and crescentic GN and 1 classic polyarteritis nodosa. Autologous granulocytes labeled with 12.3 MBq of 111In-oxine were administered intravenously. Scintigraphic studies were performed at 4 and 24 h post-injection. Compared to the non-WG cases, considered as a whole, significant accumulation of tracer in sinuses was observed in WG patients (Fisher's p = 0.02). Substantial scintigraphic amelioration was obtained in a WG case treated with methylprednisolone pulses and, in another WG case, after high doses of intravenous gamma-globulins. The complete disappearance of facial uptake was obtained after 2 months of intensive therapy (i.e., steroid, cyclophosphamide and plasma exchange) in another WG patient. 111In-oxine granulocyte imaging may be useful in clinical practice as an additional marker of disease activity and a tool of identification of upper respiratory tract involvement.

Plasmin promotes an endothelium-dependent adhesion of neutrophils. Involvement of platelet activating factor and P-selectin.

BACKGROUND: The adhesion of leukocytes to the endothelium and the edema of vessel wall may cause vascular reocclusion after thrombolytic therapy. The aim of this study was to evaluate the role of platelet activating factor (PAF) and P-selectin on the adherence of polymorphonuclear neutrophils (PMN) to the endothelium and of PAF on the increased vascular permeability induced by tissue-type plasminogen activator, streptokinase, and plasmin. METHODS AND RESULTS: We studied (1) the adhesion of 111Inlabeled PMN to human umbilical cord vein-derived cultured endothelial cells (HUVEC), (2) the transfer of 125I-labeled albumin across HUVEC monolayers, and (3) the adhesion of PMN to isolated bovine coronary arteries under flow conditions. It was found that the adhesion of PMN, induced by tissue-type plasminogen activator, streptokinase, and plasmin, correlated with the synthesis of PAF by HUVEC and was inhibited by WEB 2170, a PAF receptor antagonist. The adhesion of PMN was also inhibited by the treatment of HUVEC with anti-P-selectin antibodies or of PMN with soluble P-selectin or with anti-CD18 monoclonal antibodies. Plasmin also increased the permeability of HUVEC monolayers, an effect that was partially prevented by WEB 2170. Moreover, plasmin promoted the synthesis of PAF from isolated bovine coronary arteries and the adherence of PMN to the endothelium under flow conditions. The pretreatment of PMN with WEB 2170 or with soluble P-selectin prevented adhesion. CONCLUSIONS: The synthesis of PAF by endothelial cells at the site of plasmin generation and the endothelial expression of P-selectin may render the endothelial cell surface proadhesive for neutrophils and may favor a local increase in vascular permeability.

Clearance of polymeric IgA aggregates in humans.

Clearance of aggregated human secretory immunoglobulin A (AHS-IgA) was studied in nine patients affected by primary IgA nephropathy (IgAGN) and six normal volunteers from the medical staff. Samples of whole blood, erythrocytes, and serum were taken from 3 to 120 minutes after injection of 0.5 mg of 131iodine-labeled AHS-IgA. No significant radioactivity was recorded on erythrocytes. The clearance curve of AHS-IgA from the circulation, calculated by measuring trichloroacetic acid precipitable radioactivity in serum, was found to be biexponential with an initial fast component significantly prolonged in patients (mean half-time, 19.4 minutes, range, 14 to 26 minutes) compared with controls (mean, 12.2 minutes, range, 7.6 to 16.8 minutes; P less than 0.01). These data indicate that clearance of aggregated polymeric IgA does not involve the erythrocyte transport system and seems to be defective in IgAGN patients.

Wheat protein antigens and effector cells of aspecific immunity.

The effects of gliadin and glyc-gli on leukocyte chemiluminescence response, cytotoxic activity and locomotion were assessed in vitro. A dose-dependent increase in chemiluminescence response of neutrophils stimulated by Zymosan was observed by using gliadin at concentrations ranging between 1 and 20 micrograms. By increasing glyc-gli concentrations, a bimodal response was observed with an enhancement up to 50 micrograms/ml, followed by dose-dependent suppressive effects. The cytotoxic activity of a suspension of peripheral blood mononuclear cells on the human myeloid line K562 was assessed in a Chromium release assay. By pretreating effector cells with optimal doses of gliadin (5 micrograms/ml) or glyc-gli (50 micrograms/ml), an enhancement of cytotoxic activity, similar to that of the gamma-Interferon, could be achieved. Finally glyc-gli was found to elicit neutrophil chemokinesis. The possible implications of these findings in diseases characterized by gluten intolerance are discussed.

Processing of IgA aggregates in a rat model of chronic liver disease.

Heavy alcohol intake and/or lipotrope-deficient diet induced hepatocellular injury and mesangial deposition of IgA and often IgG in Lewis rats. The experimental animals showing more severe urinary abnormalities and histologic damage in the glomeruli had increased levels of IgA antibodies to dietary antigens and altered intestinal permeability. Based on human studies, the prolonged circulation of IgA-containing complexes associated with the liver disease could be envisaged as important for the development of mesangial IgA deposits. In order to verify this hypothesis, four groups (G) of Lewis rats were studied: G1 received thrice a weak an intragastric infusion of 1.5 ml/100 g body wt of whiskey; G2 rats were nourished with lipotrope-deficient diet; G3 rats were given both whiskey and LD diet; G4 rats were nourished with regular chow. After 12 weeks, heat-aggregated rat monomeric IgA was labeled with 133I and intravenously injected. Three control subgroups of rats, one given whiskey, one nourished with LD diet, and one with regular chow, were injected with radiolabeled heat-aggregated rat IgG. A large field-of-view digital gamma camera, equipped with an ultra-high-resolution collimator and interfaced to a dedicated computer, was used to analyze tracer kinetics and fate. The liver was the main organ involved in clearance of both test probes. The hepatic mean transit (MTT) was 11.4 +/- 11 min in G1 (proteinuria of 6.9 +/- 1.41 mg/day and hematuria +/+2), 221 +/- 19 min in G2 (proteinuria 9.1 +/- 0.64 mg/day and hematuria +2/+3), and 230 +/- 15 min in G3 (proteinuria 9.5 +/- 0.58 mg/day and hematuria +2/+3). In each case MTT value was found to be significantly prolonged compared to G4 (85 +/- 4 min). The multiple regression analysis showed that MTT values, proteinuria, and hematuria were significantly correlated (P < 0.01). Controls had trace amount proteinuria (0.82 +/- 0.17 mg/day, significantly lower than for each study group, P < 0.08) and undetectable hematuria. Similar results were obtained in control rats injected with aggregated IgG; i.e., MTT values were more prolonged in rats given whiskey or LD diet than normally nourished rats (P < 0.01). The lipotrope-deficient diet and the chronic alcohol abuse per se seem to lead to critical changes in hepatic uptake and catabolism of both an IgA and an IgG aggregate, which could account in turn for the reported appearance of renal immunoglobulin deposits in this experimental model. Due to the comparable delay in removal of IgA and IgG probes in equally nourished animals, additional factors are likely to be involved in the prominent deposition of IgA.

Effects of angiotensin II blockade on nitric oxide blood levels in IgA nephropathy.

BACKGROUND: The effects of renin-angiotensin system blockade on nitric oxide (NO), especially in pathological conditions, are far from being established. The influence of kinins and angiotensin type 2 receptor are largely speculative and based mainly on animal studies. This study was aimed to address these aspects in humans. METHODS: Eight IgA nephropathy patients with documented clinical and histological indicators of poor prognosis were given 50 mg of losartan, 10 mg of enalapril, and 40 mg of the NO donor isosorbide 5 mononitrate (as a control of NO generation) in randomized order for 7 days each. Treatment periods were separated by washout periods of 7 days each. Laboratory investigations were performed before and after each study period. Seven healthy controls received losartan and enalapril according to the same study design. RESULTS: Glomerular filtration rate remained stable while effective renal plasma flow increased with each treatment (P<0.05). Under losartan and enalapril, filtration fraction fell (P=0.02), plasma renin activity increased (P<0.05) and urinary aldosterone concentration decreased (P=0.02). Angiotensin-converting enzyme activity was reduced to the limit of detection under enalapril (P<0.001). Blood NO, detected as nitrosylhaemoglobin by a recently developed technique of spin-trap electron paramagnetic resonance, increased significantly, as expected, during treatment with isosorbide 5 mononitrate (P=0.01), with enalapril (P<0.05), and also with losartan (P<0.05). Unlike losartan, enalapril significantly reduced albuminuria (P=0.01) in this short-term period. In the seven healthy controls, neither enalapril nor losartan were able to increase blood NO levels significantly. CONCLUSIONS: Blood levels of nitrosylhaemoglobin, a surrogate marker of NO, increased under blockade of the renin-angiotensin system in patients with IgA nephropathy, but not in healthy volunteers. This increase could contribute to changes of effective renal plasma flow in renal disease states.