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E Bartoli

Publications and source records attributed to E Bartoli.

At least 91 records · Page 5Linked to original sources

Segmental reabsorption measured by micropuncture and clearance methods during hypertonic sodium infusion in the rat.

BACKGROUND: We wanted to validate by direct measurements in rat tubules a technique used to calculate segmental volume absorption by each segment of the human nephron. METHODS: Experiments were performed on 17 rats during hypertonic Na infusion prior to and after frusemide administration. Tubular samples were taken from early distal and last proximal sites. The rate of filtration of single nephrons (SNGFR) was calculated by the technique of total collection of tubular fluid using labelled inulin as a marker. Reabsorption was computed by the tubular fluid to plasma (TF/P) inulin concentration ratio. RESULTS: SNGFR was 50 +/- 4 nl/min at the distal (n = 82), 51 +/- 3 nl/min at the proximal sampling site (n = 112, P > 0.65) during baseline conditions. Percent reabsorptions were 85 +/- 1 and 69 +/- 2% respectively (P < 0.0001). During frusemide these values were 52 +/- 6 nl/min and 76 +/- 2% at the distal, 49 +/- 5 nl/min and 66 +/- 2% at the proximal site. In 83 paired proximal collections, fractional (68 +/- 1 versus 67 +/- 1% P > 0.32), absolute reabsorption (34 +/- 2 versus 33 +/- 2, P > 0.50) and SNGFR (50 +/- 2 nl/min versus 50 +/- 3 nl/min, P > 0.99) were not different between baseline and frusemide. In 25 re-collections from the distal tubule these same values were 83 +/- 2% versus 76 +/- 2%, and 48 +/- 4 nl/min versus 55 +/- 6 nl/min respectively. Very similar results were obtained in 55 paired distal-proximal collections during baseline and 42 such pairs during frusemide. In the presence of the diuretic the fractional urine excretion was significantly correlated (R = 0.83, P < 0.0001) with fractional proximal delivery, Na+ resorption by Henle's loop was 22 +/- 2% calculated from clearance data and 23 +/- 1% of GFR from micropuncture data respectively. They were not significantly different (P > 0.70) and were significantly correlated (R = 0.57, P < 0.02). CONCLUSIONS: These data demonstrate that frusemide does not act proximally and that delivery beyond the proximal tubule approximates urine flow rate during the action of the drug. The values of segmental reabsorption along the nephron computed on clearance measurements are superimposable upon those obtained directly by micropuncture.

Animals↗

Micropuncture and clearance measurements of segmental reabsorption by the rat nephron.

BACKGROUND: We wanted to verify whether the calculations of segmental tubular reabsorption obtained during water diuresis were supported by direct micropuncture measurements. METHODS: Experiments were performed on 18 rats during baseline water diuresis (B) and after the administration of frusemide (F), 10 mg/kg, by whole-kidney clearance measurements and micropuncture collections from early distal (ED) and last proximal (LP) tubular segments. RESULTS: GFR was 957+/-79 in B, 1053+/-77 microl/min in F, P>0.013. SNGFR was 38+/-1 in 166 and 38+/-1 nl/min in 165 tubules respectively, P>0.77. In LP collections the percentage reabsorption was 71+/-2 in B and 76+/-2% during F (P>0.07) in 99 and 95 samples respectively. The absolute proximal reabsorption was not changed by F (27.6+/-1.5 versus 27.7+/-1.3 nl/min, P>0.96) The data were superimposable when the analysis was restricted to paired data. The difference between ED and LP resorption was 17+/-3 during B and fell significantly (P<0.008) to 5+/-3% during F, measured by clearance techniques, and the percentage of GFR excreted during F, measured by clearance techniques, and the percentage delivery of filtrate beyond the proximal tubule, measured independently by micropuncture, were not different (27+/-2 versus 24+/-2%, P>0.10), while they were significantly correlated (P<0.04). The calculations of segmental Na reabsorption along the different nephron segments by clearance techniques were not significantly different from and were significantly correlated with the reabsorptions measured directly by micropuncture. CONCLUSIONS: The present experiments validate the calculations of reabsorption by techniques applicable to human studies of clinical physiology.

Animals↗

Benign familial macrocytosis.

We have identified a 52-year-old woman and her 27-year-old daughter with macrocytosis, normal haemoglobin and mean corpuscular haemoglobin concentration. Macrocytosis could be demonstrated from the age of 40 and 25 respectively. All blood tests were normal including vitamin B12 and folic acid. Bone marrow investigation showed rare macroblasts without other abnormalities. Endoscopy of the upper gastrointestinal tract and ultrasonography of the abdomen were normal. Thus, persistent macrocytosis was present without evidence of diseases that might account for it. In these subjects, macrocytosis is likely to be related to the presence of a genetic defect.

Adult↗

The effect of intraluminal flow rate on glomerulotubular balance in the proximal tubule of the rat kidney.

To differentiate intraluminal from peritubular factors in mediating the glomerulotubular balance, single nephron filtration rate (SNGFR) and reabsorption were measured by total collection from the last proximal segment before, and during, externally applied mechanical compression of an early proximal convolution of ninety-three rat nephrons. SNGFR fell from 55.6 +/- 2.3 nl min-1 during control conditions to 34.5 +/- 2.0 nl min-1 during compression (P < 0.0001) in sixty tubules ('responders'). Absolute reabsorption fell from 41.8 +/- 2.0 to 28.4 +/- 1.8 nl min-1 (P < 0.0001), while percentage reabsorption rose from 75 +/- 2 to 82 +/- 2% (P < 0.0001). These effects were reversible and independent of whether the compression was applied before or after the control collection. In thirty-three proximal tubules the compression procedure was not successful ('non-responders'), SNGFR remaining unchanged (36.1 +/- 2.9 vs. 36.9 +/- 2.9 nl min-1, P > 0.3). Absolute and percentage reabsorptions rose slightly, albeit significantly, from 26.1 +/- 2.1 to 30.7 +/- 2.4 nl min-1 (P < 0.0001) and from 75 +/- 3 to 85 +/- 2% (P < 0.0001). Thus, the response of reabsorption to changes in intraluminal flow is composed of two different adaptive mechanisms. The slowing of flow is present in both sets of tubules and causes a slight increase in resorption; the change in filtration per se is present only in the first set of responders, and causes an SNGFR-dependent consensual change in resorption.

Absorption↗

Discordant results from hepatitis C virus genotyping by procedures based on amplification of different genomic regions.

We compared the results of genotyping hepatitis C virus (HCV) either by PCR amplification of the core region or by hybridization of PCR-amplified products of the 5' untranslated region (5'UTR assay). Serum samples from 144 Italian anti-HCV-positive patients (106 drug abusers and 38 patients with chronic viral liver disease but no history of drug abuse) were studied. The original core region assay described by Okamoto et al. (H. Y. Okamoto, Y. Sugiyama, S. Okada, K. Kurai, Y. Akahane, Y. Sugai, T. Tanaka, K. Sato, F. Tsuda, Y. Miyakawa, and M. Mayumi, J. Gen. Virol. 73:673-679, 1992) allowed genotyping of 75 of 144 samples. A modified version of Widell et al. (A. Widell, S. Shev, S. Månsson, Y.-Y. Zhang, U. Foberg, G. Norkrans, A. Frydén, O. Weiland, J. Kurkus, and E. Nordenfelt, J. Med. Virol. 44:272-279, 1994) allowed genotyping of 11 of 79 samples (50 of 79 samples remained unclassified by the method of Okamoto et al. In contrast, all 144 samples were genotyped by the 5'UTR assay. Forty-six of 75 (61 percent) of the samples genotyped by the method of Okamoto et al. and 10 of 11 (91 percent) of the samples genotyped by the method of Widell et al. had results consistent with those obtained by the 5'UTR assay. According to the results of direct sequencing, the method of Okamoto et al. erroneously classified seven samples as having mixed infections. In conclusion, HCV genotyping seems more reliable when it is performed by the 5'UTR assay than by either of two core region assays. The major advantage provided by the 5'UTR assay is a much lower proportion of negative or indeterminate results in younger patients with histories of drug abuse or infection by genotypes other than HCV type 1.

Adolescent↗

B cell clonality in gastric lymphoid tissues of patients with Sjögren's syndrome.

OBJECTIVE: To determine the prevalence of mucosa associated lymphoid tissue (MALT) in the stomach and of a possible antigen driven proliferation, in patients with Sjögren's syndrome (SS). METHODS: Twenty one patients with primary SS and 80 dyspeptic controls underwent upper endoscopy. Lymphoid tissue and Helicobacter pylori were assessed by histopathological analysis. Epstein-Barr virus (EBV) or human herpes virus-6 (HHV-6) genome were studied by polymerase chain reaction (PCR) DNA amplification. Two PCR VDJ procedures were used to detect immunoglobulin heavy chain (IgH) gene rearrangement. RESULTS: Organised MALT was found in 33.3% of the patients, compared with 21.5% of the controls (NS). H pylori infection was seen in 71% of patients and 63% of controls. Genomic EBV or HHV-6 was found in a minor portion of SS gastric tissues. B cell expansion was detected in nine of the 21 patients. Infectious agents in the stomach might have contributed to B cell clonality only in 55.5% of the cases. No strict relationship was found between lymphoid follicles and clonality. CONCLUSION: Lymphoid accumulation in the gastric mucosa is common in Sjögren's syndrome, but full evidence for an antigen driven B cell expansion could not be demonstrated. Only a portion of those with clonal B cell expansion had evidence of an infectious agent. Other unknown infectious agents or factors related to the underlying disease (autoantigen) and its tissue environment may have a further role as possible causes of B clonal expansion in the gastric mucosa.

Adult↗

B-cell clonality and infection with Helicobacter pylori: implications for development of gastric lymphoma.

BACKGROUND: Although Helicobacter pylori has been implicated in the pathogenesis of gastric mucosa associated lymphoid tissue (MALT) and MALT lymphoma, it is not known how it may trigger these lesions and whether there is an identifiable pre-neoplastic stage. AIMS: To investigate the relation between MALT, H pylori infection, and B-cell clonality (a potential marker of pre-neoplastic lesions). PATIENTS: 141 subjects with simple dyspepsia. METHODS: Gastric biopsy specimens from all patients were examined for MALT and H pylori. Of these, 25 consecutive MALT positive specimens were scored for features of MALT lymphoma and VDJ clonality studied by polymerase chain reaction. RESULTS: Overall, prevalence was 62% for H pylori and 46% for MALT. VDJ clonality was frequent in the sub-group studied (nine of 25), mostly associated with lymphoid follicles (eight of nine or 89%), and with a high scoring for MALT lymphoma. VDJ clonality was equally frequent in patients with and without H pylori (seven of 20 and two of five or 35% and 40% respectively). CONCLUSIONS: B-cell clonality is unexpectedly common in subjects with simple dyspepsia and MALT raising clinical management questions. These findings also suggest that the cascade MALT formation--B-cell clonality--MALT lymphoma may not be uniquely associated with H pylori infection.

Adolescent↗

Serum soluble vascular-cell adhesion molecule-1 (VCAM-1) in patients with acute and chronic liver diseases.

Our aim was to ascertain the degree of variation of serum soluble vascular cell adhesion molecule-1 (VCAM-1) concentrations according to the nature and the severity of an underlying liver disease. One-hundred forty sera collected from 123 patients (83 male, 40 female) with acute hepatitis (n = 14), mild chronic liver disease (n = 52) or cirrhosis (n = 57) of different etiologies as well as from 17 healthy blood donors (8 male, 9 female) were studied. Soluble VCAM-1 concentration was measured immunoenzymatically. One-way analysis of variance revealed a significant variability of the mean values of soluble VCAM-1 among groups (F = 80.02, p < 0.0001). All groups of patients had higher soluble VCAM-1 than controls; moreover, patients with acute hepatitis and patients with cirrhosis had higher soluble VCAM-1 levels than patients with mild chronic liver disease (Bonferroni's test, p < 0.01). These results did not change after stratification of patients according to the etiology (viral or toxic) of liver disease (two-way analysis of variance: grouping factor diagnosis, F = 60.39, p < 0.0001; grouping factor etiology, F = 1.73, p NS). Cholinesterase, total bilirubin, circulating thrombocytes and blood area nitrogen were the independent predictors of the concentration of soluble VCAM-1. In conclusion, patients with liver disease have high serum soluble VCAM-1, which seems to reflect more the severity of impairment of liver function rather than the etiologic nature of the disease.

Acute Disease↗

Abnormalities of insulin receptors in spontaneously hypertensive rats.

Insulin resistance is present in some strains of rats with genetic hypertension. To determine whether this abnormality is present at the level of the insulin receptor, we compared insulin sensitivity, insulin receptor binding, and mRNA levels in tissues of 10-week-old spontaneously hypertensive rats (SHR) and their normotensive Wistar-Kyoto (WKY) controls. Because we have previously demonstrated an inverse relationship between dietary sodium intake and renal insulin receptor density and mRNA levels in normal Sprague-Dawley rats, the two rat strains in the current experiment were fed either low salt (0.07% NaCl) or high salt (7.5% NaCl) chow until the SHR became hypertensive. Fasting plasma glucose and plasma insulin levels did not differ between SHR and WKY and were not affected by salt intake. When the rats were maintained on the low salt diet, the rate of glucose infusion required to main euglycemia during a hyperinsulinemic clamp was significantly lower in SHR than WKY. High salt diet decreased the rate of glucose utilization during the hyperinsulinemic clamp in WKY but not SHR. During the low salt diet, insulin infusion decreased sodium excretion in both WKY and SHR. When the rats were maintained on the high salt diet, the antinatriuretic response to insulin was blunted in WKY but not SHR. Both the density and mRNA levels of insulin receptor were comparable in the kidney of WKY and SHR, but only WKY had the previously demonstrated decrease in receptor number and mRNA levels when fed the high salt chow. Hepatic insulin receptor mRNA levels were significantly lower in SHR than WKY fed the low salt diet. High salt diet decreased significantly insulin receptor mRNA levels in the liver of WKY but not of SHR. Thus, SHR appear to have lost the feedback mechanism that normally limits insulin-induced sodium retention when extracellular volume is expanded. A decreased expression of insulin receptor in the liver of SHR provides a possible explanation for the insulin resistance and decreased insulin clearance present in this strain.

Animals↗

Risk factors for vascular disease and arteriovenous fistula dysfunction in hemodialysis patients.

Vascular access dysfunction is an important cause of morbidity for dialysis patients and a major contributor to hemodialysis cost. Thrombosis is a leading cause of vascular access failure, and usually results from stenotic lesions in the venous outflow system. This study was designed to explore the impact of serum levels of various risk factors for thrombosis and accelerated fibrointimal hyperplasia on progressive stenosis, and the subsequent thrombosis of hemodialysis fistula. A cross-sectional and 2-yr prospective pilot study was performed in 30 nondiabetic hemodialysis patients with primary arteriovenous fistula. Venous dialysis pressure, urea recirculation, color Doppler sonography, and angiography were used to monitor vascular access patency. Eleven patients (37%) developed a progressive stenosis in the venous circuit, which was complicated by thrombosis in three patients. Compared with the patients without fistula dysfunction, these patients had higher serum levels of monocyte chemoattractant protein-1 and interleukin-6, two cytokines that regulate the proliferation of vascular smooth muscle cells, which is the key mechanism in the pathogenesis of fistula stenosis. In addition, they had hyperinsulinemia, hyperlipidemia, and increased plasma levels of two hemostasis-derived risk factors for thrombosis: plasminogen activator inhibitor type 1 and factor VII. Monocyte chemoattractant protein-1, interleukin-6, plasminogen activator inhibitor type 1, factor VII, triglycerides, and the ratios for cholesterol/HDL-cholesterol, apolipoprotein (apo) A-I/ apo C-III, apo A-I/apo B, and glucose/insulin were independent predictors of fistula dysfunction. This study demonstrates the influece of cytokines, hemostasis-derived vascular risk factor, hyperinsullnemia, and abnormallties of lipids and apolipoproteins on primary fistula survival. The assessment of these factors might be useful for the identification of the patients at risk of fistula stenosis and thrombosis.

Aged↗

Diagnostic usefulness of acute-phase protein measurement in hepatocellular carcinoma.

To compare the diagnostic usefulness as markers of hepatocellular carcinoma (HCC) of alpha1-antitrypsin, C-reactive protein, and alpha1-acid glycoprotein (all determined by nephelometric methods), we studied 132 subjects (74 male, 58 female): 43 had mild chronic liver disease, 32 cirrhosis, 24 HCC; 33 were controls. A total of 29.2% of the patients with HCC had alpha1-acid glycoprotein > 100 mg/dl, 75.0% had alpha1-antitrypsin > 220 mg/dl, 70.8% had C-reactive protein > 5 mg/L. In cirrhotics, frequencies were 3.1, 50.0 and 59.4%, respectively; in patients with mild chronic liver disease, 14.0, 11.6, and 32.6% (chi2 12.3, p < 0.01; chi2 47.3, p < 0.0001; chi2 38.0, p < 0.0001, respectively). alpha1-fetoprotein performed better than all acute-phase proteins. We conclude that, due to their low specificity and/or sensitivity, none of the three acute-phase reactants tested can be recommended for diagnostic use as biological markers of HCC in Western patients.

Acute-Phase Proteins↗

Methotrexate in polymyalgia rheumatica: preliminary results of an open, randomized study.

OBJECTIVE: Steroids are the only treatment of polymyalgia rheumatica (PMR). We report the effects of methotrexate (MTX) plus prednisone versus prednisone alone in PMR. METHODS: Twenty-four patients with recent onset PMR were studied in a randomized prospective study lasting one year. Patients were given MTX (MTX arm) 10 mg intramuscularly plus prednisone every week, or prednisone alone (Pred arm). After 6 months an attempt was made to stop prednisone, and to use the lowest possible dose over the next 6 months. RESULTS: At the 12th month, all patients were in clinical remission, acute phase reactants were in the normal range in both arms of the study, 6 patients were no longer taking steroids in the MTX arm versus 0/12 in the Pred arm, and the amount of prednisone in the 2 groups was statistically different (1.84 versus 3.2 g; p < 0.0001). In addition, bone mineral density was significantly decreased in the Pred arm, but not in the MTX arm. CONCLUSION: The MTX regimen allowed the use of much less prednisone over one year to obtain full control of PMR with no loss of efficacy. It also allowed sparing of bone in elderly patients at increased risk of osteoporotic fractures.

Aged↗

Increase of bone mineral density and anabolic variables in patients with rheumatoid arthritis resistant to methotrexate after cyclosporin A therapy.

OBJECTIVE: To determine the bone mineral density (BMD) and anabolic variables in a cohort of patients with severe, early rheumatoid arthritis (RA) resistant to weekly doses of methotrexate (MTX), after addition of cyclosporin A (CyA) therapy. METHODS: We studied 10 rheumatoid factor positive patients of 58 with early erosive, aggressive RA with poor response to a 6 month course of MTX (< 20% improvement in the American College of Rheumatology core set of criteria). BMD was assessed at entry, after 6 months of MTX, and after a further 6 months of combination therapy of MTX plus CyA. Bone Gla protein (BGP) dehydroepiandrosterone sulfate (DHEAS), and insulin-like growth factor-1 (IGF-1, somatomedin C) levels were determined along with clinical variables and acute phase reactants (C-reactive protein, erythrocyte sedimentation rate). RESULTS: An average BMD decline of 4.05 +/- 0.8% (mean, SD) occurred in the first 6 months of MTX treatment, along with a statistically significant decline of IGF-1 (-24.8%), DHEAS (-21.6%), and BGP (-19.7%) levels. After adding CyA 3 mg/kg daily for 6 months, BMD had increased by 3.9 +/- 0.97%, IGF-1 by 42.4%, DHEAS by 34.2%, BGP by +34.3%. These changes mirrored the clinical variables (Health Assessment Questionnaire, morning stiffness, joint count) and acute phase reactants, which improved in a statistically significant manner. CONCLUSION: Patients with active RA, even in the early phases, lose bone very rapidly. Effective control of systemic inflammation allowed a rapid rescue of BMD, at least in the short term. This happened with a simultaneous increase in some anabolic variables such as IGF-1, BGP, and DHEAS.

Acute-Phase Proteins↗

Immunosuppressive treatment of the nephrotic syndrome due to mesangial lesions.

To assess the effectiveness of an intensive immunosuppressive regimen on the nephrotic syndrome due to mixed membranous and mesangial lesions, we studied 18 patients with nephrotic syndrome and miscellaneous histologic features characterized by mesangial proliferation and sclerosis, non-specific basement membrane changes such as thickening, fraying and scalloping, in the absence of extensive immune complex deposition by immunofluorescence. The patients were treated with an immunosuppressive regimen that combined prednisone and cyclophosphamide for at least 6 months with the following schedule: 1) induction with prednisone daily 250 to 750 mg i.v. for 3 to 8 days, plus cyclophosphamide 100 to 200 mg p.o. daily; 2) maintenance with prednisone 100 to 200 mg p.o. in alternate days for 30 to 75 days, and cyclophosphamide as before; 3) tapering, with prednisone in alternate day regimen, reduced on average by 25 mg every month, plus cyclophosphamide as before; 4) discontinuation of cyclophosphamide and slow withdrawal of prednisone. Treatment lasted on average 9 months, with an average cumulative dose of prednisone of 9.2 g and of cyclophosphamide of 26.7 g. At the end of treatment, 14 patients had a complete remission and 4 remained stable. On longer follow-up, one out of these 4 patients, who had renal failure before treatment, subsequently progressed to end-stage renal disease. Nine patients relapsed after an average remission of 6 years. Eight of them remitted completely on a repeat cycle. One patient refused the retreatment and progressed to end-stage renal disease within one year. After an average follow-up of 7.3 +/- 1.1 years, plasma creatinine for the whole group had fallen from 138 +/- 26 to 103 +/- 20 mumol/l and proteinuria from 6.7 +/- 0.7 to 0.4 +/- 0.2 g/d (p < 0.001). In conclusion, in patients with these forms of nephrotic syndrome this immunosuppressive regimen is highly effective in inducing remission, in preventing progression to end-stage renal disease and in treating relapses.

Adult↗

Molecular mechanisms of insulin resistance in arterial hypertension.

The associations between insulin resistance, hyperinsulinaemia, and hypertension are well recognized. Hyperinsulinaemia induces hypertension through increased renal tubular reabsorption of sodium and water, increased sympathetic nervous system activity, proliferation of vascular smooth muscle cells, and alterations of transmembrane cation transport. At physiological concentrations, insulin decreases urinary sodium excretion, an action mediated by binding to specific high-affinity receptors. Insulin resistance is present also in strains of rats with genetic hypertension (spontaneously hypertensive and Dahl salt-sensitive rats) that can be utilized as models to study the molecular mechanisms of this abnormality. In normal rats, the number and mRNA levels of insulin receptors in the kidney are inversely related with dietary sodium content, suggesting the existence of a feedback mechanism that limits insulin-induced sodium retention when extracellular fluid volume is expanded. We have investigated the relationships between dietary sodium intake and renal insulin receptors in spontaneously hypertensive rats and have found that in this strain the feedback mechanism is abolished. In addition, spontaneously hypertensive rats have decreased expression of the insulin receptor gene in the liver and decreased receptor autophosphorylation and phosphorylation of an endogenous substrate (IRS-1) in liver and muscle. These observations provide a potential explanation for the decreased sensitivity to insulin present in spontaneously hypertensive rats. In these rats, the loss of the capability to down-regulate insulin receptor in the kidney when extracellular fluid volume is expanded can lead to further sodium retention and might play a role in the development and maintenance of hypertension.

Animals↗

Non-specific increase of serum carbohydrate antigen 19-9 in patients with liver disease associated with increased circulating levels of adhesion molecules.

Sialyl-Lewisa antigen (SLe(a)), the immune determinant of carbohydrate antigen 19-9 (CA 19-9), is the ligand of E-selectin. To verify the possibility of an association between nonspecific elevation of CA 19-9 and adhesion molecules, sera from 12 patients with acute hepatitis, 55 with non-cirrhotic chronic liver disease, 33 with cirrhosis and 25 with hepatocellular carcinoma, were tested for common liver function tests. Besides, CA 19-9 and soluble forms of E-selectin, VCAM-1 and ICAM-1 were measured immunoenzymatically. One-way analysis of variance demonstrated that mean CA 19-9 concentration differed among groups (F 15.27, P < 0.0001) with the highest values found in patients with acute hepatitis. By univariate analysis, the strongest correlation of CA 19-9 was with soluble ICAM-1, which by stepwise multiple regression analysis was the only independent predictor of elevated CA 19-9 (multiple R 0.560). The association between ICAM-1 and CA 19-9 might originate in the biliary cells where they might be simultaneously overexpressed during inflammatory processes.

Acute Disease↗