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Biomedical subjects

R Boero

Publications and source records attributed to R Boero.

At least 55 records · Page 3Linked to original sources
PubMed1988

Erythrocyte Na,K pump activity and arterial hypertension in uremic dialyzed patients.

We have evaluated in 26 uremic patients [21 on hemodialysis, 5 on continuous ambulatory peritoneal dialysis (CAPD)], 11 normotensive, and 15 hypertensive (MAP greater than 110 mm Hg) patients the following properties: a) erythrocyte (RBC) Na concentration [Nai] and ouabain-sensitive and -resistant Na effluxes; b) the effect of uremic sera on ouabain-sensitive Na efflux in normal RBC; c) serum digoxin-like immunoreactivity; d) cardiac index and total peripheral resistance. In 19 healthy subjects a) and c) were also evaluated. RBC Na,K pump activity was lower in uremic patients than in normal subjects (P less than 0.0005), and lower in hypertensive (P less than 0.02) than in normotensive patients. Serum from uremic patients inhibited ouabain-sensitive Na efflux in normal RBC, the inhibition being correlated with both the rate constant for ouabain-sensitive Na efflux (r = -0.67; P less than 0.005) and [Nai] (r = 0.43; P less than 0.05) of RBC of patients from whom the serum was obtained. Inhibition of ouabain-sensitive Na efflux was significantly higher with serum from hypertensive than from normotensive patients (P less than 0.05). Serum digoxin-like immunoreactivity was present in all uremic patients (0.402 +/- 0.054 ng/ml in normotensive and 0.428 +/- 0.040 ng/ml in hypertensive, P = ns), while it was not detectable in normal subjects. Hypertensive patients had peripheral resistance significantly higher than normotensive (P less than 0.05), while cardiac index was similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Proteins↗
PubMed1988

Abnormalities of sodium transport by sodium, potassium-activated adenosine triphosphatase in erythrocytes from obese children.

1. Intracellular Na+ concentration [Na+]i and Na+ extrusion catalysed by sodium potassium-activated adenosine triphosphatase (Na+, K+-pump) were evaluated in erythrocytes from 21 obese children and 20 normal weight- and age-matched controls. 2. Obese children showed a significantly decreased Vmax. for Na+, K+-pump-mediated Na+ efflux (5638 +/- 338 vs 7597 +/- 335 mumol h-1 litre-1 of cells mean +/- SEM, P = 0.01), while [Na+]i (9.3 +/- 0.3 vs 9.1 +/- 0.5 mmol/litre of cells, mean +/- SEM, NS) and Na+ efflux in fresh cells (2380 +/- 153 vs 2533 +/- 180 mumol h-1 litre-1 of cells, mean +/- SEM, NS) were similar in both groups. 3. Mean diastolic blood pressure was significantly higher in obese children than in controls, although both groups were normotensive (73.8 +/- 1.3 vs 66.2 +/- 1.9 mmHg, mean +/- SEM, P = 0.009). 4. Abnormal Na+, K+-pump activity is present in individuals with idiopathic obesity. 5. The possible link between obesity and blood pressure regulation may be mediated through modifications in Na+,K+-pump activity.

Adolescent↗
PubMed1988

Pathogenesis of arterial hypertension in chronic uraemia: the role of reduced Na,K-ATPase activity.

In 38 uraemic dialysed patients (17 normotensive, 21 hypertensive) we measured (1) erythrocyte sodium concentration [Nai] and ouabain-sensitive sodium efflux, and (2) arterial pressure, cardiac index and total peripheral resistance. Erythrocyte Na-K pump activity was lower in hypertensive than in normotensive patients (P less than 0.02). Hypertensive patients had significantly higher peripheral resistance than normotensive patients (P less than 0.05), while the cardiac index was similar in both groups. Inverse correlations were found between the rate constant for ouabain-sensitive sodium efflux in erythrocytes and both systolic and diastolic pressure (r = -0.43 and r = -0.45, respectively; P less than 0.01) and total peripheral resistance (r = -0.76; P less than 0.0001). Our data suggest that reduced sodium transport by the Na-K pump plays a role in the pathogenesis of arterial hypertension in patients with chronic uraemia.

Blood Pressure↗
PubMed1987

Ultrastructural glomerular findings in cryoglobulinemic glomerulonephritis.

Thirty-three renal biopsies of patients affected by cryoglobulinemic glomerulonephritis (CRYGN) were investigated by electron microscopy, paying particular attention to the nature of cells responsible of glomerular hypercellularity, the presence and site of electron-dense deposits and their ultrastructural characteristics. Personal as well as literature data suggest (a) diffuse glomerular hypercellularity found in most cases of CRYGN is mainly due to polymorphonuclear leukocytes and even more to monocyte exudation; (b) the interposition of the latter cell type in the glomerular capillary wall is the main responsible cause of the frequent occurrence of the membranoproliferative pattern in CRYGN, and (c) peculiar structures found in the electron dense deposits are characteristic of CRYGN and related to cryoglobulin composition. Electron microscopy therefore seems to be a valuable diagnostic procedure for this type of glomerulonephritis.

Cryoglobulinemia↗
PubMed1985

Evaluation of ouabain-insensitive red blood cell cation transport in uremic patients.

The authors present the results of a simultaneous assay of: intracellular Na+ and K+ concentrations, Na+ and K+ outward bumetanide-sensitive effluxes (Na+, K+ cotransport), Na+ efflux stimulated by extracellular Li+ (Na+, Li+ countertransport), and ouabain- and bumetanide-resistant Na+ and K+ effluxes (passive membrane permeability) performed in red blood cells from 15 uremic patients an regular hemodialysis and from 12 normal subjects, with an established flux assay. Na+ and K+ effluxes by the Na+, K+ cotransport system were significantly (p less than 0.01) lower in uremic patients then in normals (219 +/- 37 vs 82 +/- 17 mumol/l RBC/h and 251 +/- 29 vs 139 +/- 14 mumol/l RBC/h respectively). In normal subjects the bumetanide sensitive Na+ and K+ effluxes were strongly (r = 0.89; p less than 0.01) intercorrelated; and the intracellular Na+ concentration was related to the outward Na+ cotransport flux (r = 0.53; p approximately 0.05). Among uremic patients these correlations were not found. Na+ and K+ intracellular concentrations, passive Na+ and K+ permeability, and Na+, Li+ countertransport activity were not different among uremic patients and normal controls. In conclusion, in uremic dialyzed patients, red blood cell Na+, K+ cotransport activity is quite uniformly suppressed. The possible pathogenesis of this disfunction is still speculative and deserves further studies.

Adult↗
PubMed1985

Effects of an intravenous saline load on erythrocyte sodium transport in normal human subjects.

The effects of a 2 litre intravenous infusion of saline (0.9% NaCl solution) over 3 h on erythrocyte transmembrane sodium transport were studied in 12 normal human subjects. After saline infusion a significant (P less than 0.01) reduction of both outward Na+,K+ pump- and Na+,K+ cotransport-mediated Na+ effluxes was observed. The Na+,Li+ countertransport rate and the passive Na+ permeability did not change. The incubation of the subjects' erythrocytes, obtained on a separate occasion, with their own plasma taken after the saline infusion, induced an inhibition of both Na+,K+ pump and Na+,K+ cotransport outward sodium fluxes. The percentage decrease after incubation was closely correlated with the percentage reduction induced by the saline infusion in vivo (r = 0.93 for the pump and r = 0.96 for cotransport; P less than 0.01). These data suggest that extracellular fluid volume expansion affects the release of circulating factors modulating sodium transport by the Na+,K+ pump and by Na+,K+ cotransport.

Adult↗
PubMed1985

Acute effects of hemodialysis on erythrocyte sodium fluxes in uremic patients.

The acute effects of both acetate and bicarbonate hemodialysis on erythrocyte transmembrane sodium fluxes were investigated in 15 patients with chronic uremia. We observed a significance (p less than 0.01) stimulation of the Na+,K+ pump in both procedures, with a significant correlation to the amount of fluid removed during hemodialysis (r = 0.56, p less than 0.03). Outward Na+ cotransport fluxes significantly rose (p less than 0.05) after acetate hemodialysis and decreased (p less than 0.05) after bicarbonate hemodialysis. Minor and not significant pre- and posthemodialysis bidirectional changes were observed as regards the intraerythrocyte Na+ and K+ concentration, passive Na+ and K+ permeability, and Na+,Li+ countertransport. Hemodialysis may acutely affect the erythrocyte sodium pump and cotransport fluxes, possibly through the modulation of hormonal factors triggered by the extracellular volume changes.

Acetates↗
PubMed1983

Blood pressure behaviour in hemodialysis patients treated for 10 years.

A longitudinal analysis of blood pressure was performed in 30 patients on hemodialysis for at least 10 years, in order to clarify the long-term outcome of hypertension in dialysis patients. Before the start of the dialysis treatment 22 (73.3%) patients were hypertensive, while, after 10 years, only 5 (16.6%) were still hypertensive. Body weight tended to decrease progressively throughout the period of observation. Hypertension disappeared in the younger patients while it remained/appeared in those who were order showing the characteristics of systolic hypertension. Except for hematocrit no significant differences in metabolic findings were found between normotensive and hypertensive patients. ECG abnormalities were found to be more frequent after 10 years of dialysis than before the start of treatment. High blood pressure tends to disappear progressively in hemodialysis patients and to be no longer a problem in long-term survivors.

Adolescent↗
PubMed1981

Effects of blood transfusion on cellular immunity.

To evaluate the effect of transfusion on immunity, 14 uraemic patients treated with 3 blood transfusions from a single donor, at weekly intervals, were studied: in 5 cases HLA-A,B were compatible, in 9 cases they were not. As markers of cellular and humoral immunity DNCB, PPD skin tests, spontaneous and active E-rosettes, EAC-rosettes, surface membrane immunoglobulins, C3, C4, C3d, serum immunoglobulins, circulating immune complexes and C-reactive protein were investigated. This protocol was applied before transfusions, 1 week after each transfusion (day +7, +14, +21) and 20 weeks later (day +80). Before transfusions 8/14 patients were DNCB negative; both spontaneous and active E-rosettes were below normal range. The other parameters were normal. On day +7 T and B lymphocytes were increased, while the other parameters were unmodified. On day +21 there was a significant reduction (p less than 0.5) in T lymphocytes in patients treated with compatible transfusions. On day +80 3/3 DNCB positive patients, treated with compatible transfusions, became negative and 1/3 DNCB positive patients, treated with random transfusions, also became negative. Three/fourteen patients showed a decrease in B lymphocytes. The other results were unchanged. Our preliminary results suggest that transfusions, either from an HLA compatible donor or not, can impair lymphocyte function.

Adult↗
PubMedDate not supplied

Sympathetic nervous system and chronic renal failure.

The aim of this work was to review evidence on the role of the sympathetic nervous system (SNS) in chronic renal failure (CRF). Three main points are discussed: 1) SNS and pathogenesis of arterial hypertension; 2) SNS and cardiovascular risk; 3) implication of SNS in arterial hypotension during hemodialysis. Several lines of evidence indicate the presence of a sympathetic hyperactivity in CRF, and its relationship with arterial hypertension. It is suggested that diseased kidneys send afferent nervous signals to central integrative sympathetic nuclei, thus contributing to the development and maintenance of arterial hypertension. The elimination of these impulses with nephrectomy could explain the concomitant reduction of blood pressure. Several experiments confirmed this hypothesis. Regarding SNS and cardiovascular risk, some data suggest that reduced heart rate variability identifies an increased risk for both all causes and sudden death, independently from other recognized risk factors. Symptomatic hypotension is a common problem during hemodialysis treatment, occurring in approximately 20-30% of all hemodialysis sessions and is accompanied by acute withdrawal of sympathetic activity, vasodilation and relative bradicardia. This reflex is thought to be evoked by vigorous contraction of a progressively empty left ventricle, activating cardiac mechanoceptors. This inhibits cardiovascular centers through vagal afferents, and overrides the stimulation by baroreceptor deactivation. Alternative explanations include cerebral ischemia and increased production of nitric oxide, which inhibit central sympathetic activity. It is hoped that therapies aimed at modulating sympathetic nerve activity in patients with CRF will ameliorate their prognosis and quality of life.

Animals↗
PubMedDate not supplied

Hemophagocytic syndrome in a case of splenic large B-cell lymphoma.

A case of splenic large B-cell lymphoma with hemophagocytic syndrome is reported. The difficulties of diagnosis are emphasized especially when peripheral lymph nodes or bone marrow lymphomatous infiltration are not present. Diagnostic criteria for hemophagocytic syndrome and their relationship with the pathogenesis of the disease are also stressed.

Bone Marrow↗
PubMedDate not supplied

3 R study: renal outcome in renal ischemia: revascularisation or medical treatment.

Ischemic nephropathy refers to the kidney damage following stenosis or an obstructive lesion in the main kidney arteries. This disorder has been overlooked in the past and a more rational and specific use of clinical criteria, and the development of not very invasive techniques with a good diagnostic accuracy such as spiral CT angiography, NMR angiography and echo-colour-Doppler have improved our ability to identify these patients. It is therefore likely that, in the next few years, we will find ourselves treating an increasing number of patients with renovascular ischemic disorders. Transluminal angioplasty and, more recently, the use of endovascular stents, have led to a marked improvement in the treatment of stenoses and, together with vascular surgery, allow to treat almost all patients with this disorder. There is, however, a lack of prospective and controlled studies, which demonstrate the long term benefit of revascularization treatment, as compared with optimum conservative treatment in reducing cardiovascular mortality, cardiovascular events and preserving renal function. The Ischemic Nephropathy Study Group of the Italian Society of Nephrology has organized a prospective, controlled study over a period of three years, aimed at comparing the effect of revascularization versus medical therapy in 300 patients with renal artery stenosis, ranging between 50 and 90 per cent, who will be randomly assigned to the two treatments. End point will be cardiovascular mortality and morbidity and need for renal replacement therapy.

Follow-Up Studies↗
PubMedDate not supplied

Verapamil versus amlodipine in proteinuric non-diabetic nephropathies treated with trandolapril (VVANNTT study): design of a prospective randomized multicenter trial.

Angiotensin converting enzyme inhibitors (ACEI) are the most effective antiproteinuric agents and should be used as first-line drugs in both diabetic and non-diabetic proteinuric nephropathies. The role of calcium channel blockers (CCB) is much more controversial. In diabetic patients verapamil and diltiazem seem more effective than dihydropyridines in reducing urinary protein excretion, and have additive effects with ACEI, but little is available on chronic treatment of non-diabetic nephropathies for non-dihydropyridine CCBs. To test whether the combination of verapamil 180 mg or amlodipine 5 mg with trandolapril 2 mg reduces urinary protein excretion more than trandolapril 2 mg alone, we planned a prospective, randomized, double-blind, multicenter trial. The secondary aims are to evaluate the effects of both treatments on the selectivity of proteinuria and check their safety. Consecutive patients aged between 18 and 70 years with non-diabetic proteinuria > or =2 g/24 h and plasma creatinine < 3 mg/dl or creatinine clearance > or = 20 ml/min are asked to participate. After a four-week run-in during which previous antihypertensive therapy is withdrawn, a single dose of trandolapril 2 mg is given once a day in open conditions for four weeks. At the end of this period patients are randomly assigned to receive once a day, in a double blind fashion, either trandolapril 2 mg and verapamil 180 mg [plus a placebo], or trandolapril 2 mg plus amlodipine 5 mg. They are monitored after one, two, five and eight months.

Adult↗