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Biomedical subjects

M Aparicio

Publications and source records attributed to M Aparicio.

At least 55 records · Page 3Linked to original sources
PubMed1997

Henoch-Schönlein purpura with immunoglobulin A nephropathy and abnormalities of immunoglobulin A in a Wiskott-Aldrich syndrome carrier.

Abnormalities of immunoglobulin A1 (IgA1) glycosylation have been described in patients with IgA nephropathy (IgAN), whether primitive or secondary to Henoch-Schönlein purpura. The Wiskott-Aldrich syndrome, an X-linked recessive disorder, is associated with abnormalities of IgA. Renal involvement with mesangial IgA deposition identical to that found in IgAN has been reported during this affection. We report the case of a female carrier of the Wiskott-Aldrich syndrome presenting with Henoch-Schönlein purpura and abnormalities of IgA glycosylation, as previously reported in patients with IgAN. The galactosylation abnormalities of IgA could be linked to the patient's status as carrier of the Wiskott-Aldrich syndrome and could contribute to the pathogenesis of IgAN.

Adult↗
PubMed1997

Antioxidant effects of a supplemented very low protein diet in chronic renal failure.

Increased peroxidation of lipids in red blood cells (RBC) in patients with advanced chronic renal failure (CRF) reflects increased generation of reactive oxygen species (ROS), which may contribute to the metabolic damage induced by CRF and to its progression. We have evaluated parameters indicative of lipoperoxidation (LPO) of RBC at baseline in patients with CRF compared to controls, and the effects of a very low protein diet supplemented with amino and keto acids and vitamins A, C, E (VLPD) over a 6-month period. The presence of peroxidation damage in CRF patients before the administration VLPD was demonstrated by elevated levels of free malondialdehyde (MDA) (p < .0003) and decreased levels of polyunsaturated fatty acids (PUFA), particularly C20:4 (p < .001), C22:4 (p < .0001) and C22:5 (p < .0001) when compared to controls. Similarly, RBC vitamin E content was significantly decreased (p < .0001) while enzymatic activities were unalterated. VLPD reduced erythrocyte LPO as suggested by (a) decreased levels of free and total RBC MDA (p < .003 and p < .03, respectively), (b) increased levels of PUFA, particularly C22:4 and C22:5 (p < .003 and p < .03, respectively), and (c) increased levels of vitamins A and E (p < .001 and p < .04, respectively) as compared to prediet results. Antioxidant enzyme activities were not modified. These results suggest that VLPD has a protective role against LPO of erythrocytes in patients with CRF.

Adult↗
PubMed1997

Low protein diet in uremia: effects on glucose metabolism and energy production rate.

Low-protein diets (LPD) increase insulin-mediated glucose disposal in chronic renal failure (CRF), but the fate of the better utilized glucose and the effect on energy production rate are unknown. Using a two-step (1 and 5 mU x kg(-1) x min(-1)) euglycemic hyperinsulinemic clamp combined with indirect calorimetry, we studied the effects of a LPD (0.3 g x kg(-1) x day(-1), supplemented with essential amino acids and ketoanalogs) in six patients suffering from chronic renal failure. After three months of diet, no significant change was observed concerning glomerular filtration rate, body wt, or arterial pH. In the postabsorptive state, plasma glucose and insulin levels were significantly lower, and energy production rose from 15.72 +/- 0.48 to 17.16 +/- 0.67 Cal x kg(-1) x min(-1) (P < 0.05). Insulin-stimulated glucose oxidation (2.36 +/- 0.29 vs. 3.37 +/- 0.35 mg x kg(-1) x min(-1); P < 0.05 at first clamp step) and nonoxidative disposal (P < 0.05 at both clamp steps) increased after LPD. This confirms that LPD ameliorates insulin sensitivity in CRF, even for low plasma insulin concentrations. Since energy production rate is increased by LPD, the caloric intake should be increased when protein intake is restricted.

Adult↗
PubMed1997

A low-protein diet improves insulin sensitivity of endogenous glucose production in predialytic uremic patients.

A low-protein, low-phosphorus diet (LPD) has been shown to improve insulin sensitivity in uremic patients; however, this improvement has not been studied at low physiologic concentrations of plasma insulin, and the metabolic pathways concerned with this improvement have not been located. We used the glucose clamp technique at a low (0.25 mU.kg-1.min-1) level of hyperinsulinemia associated with the infusion of D[6,6-2H2] glucose to assess the insulin sensitivity of endogenous glucose production (EGP). Eight nondialyzed uremic patients were studied before and after 3 mo on an LPD providing 0.3 g/kg protein, 5-7 mg P/kg, and 146 kJ/kg (67% of energy as carbohydrates and 30% as lipids) per day, supplemented with ketoanalog amino acids. Postabsorptive plasma glucose and insulin declined after 3 mo of the diet (plasma glucose: 5.0 +/- 0.1 mmol/L before compared with 4.7 +/- 0.1 mmol/L after the LPD, P < 0.05; plasma insulin: 82.4 +/- 20.7 pmol/L before compared with 48.8 +/- 6.0 pmol/L after, P < 0.05). Postabsorptive glucose turnover rates did not change with the diet (2.06 +/- 0.14 mg.kg-1.min-1 before compared with 2.11 +/- 0.17 mg.kg-1.min-1 after LPD; NS). The insulin metabolic clearance rate was enhanced after the diet, so a lower level of hyperinsulinemia was obtained during the clamp (168.8 +/- 28.1 pmol/L before compared with 115.2 +/- 14.7 pmol/L after; P < 0.05). However, EGP was more easily inhibited after the diet (0.90 +/- 0.31 mg.kg-1.min-1 before compared with 0.30 +/- 0.17 mg.kg-1.min-1 after; P < 0.05), providing evidence of an improved insulin sensitivity of this parameter. This beneficial influence takes place at a physiologic level of hyperinsulinemia, and it probably plays an important role in the better glucose tolerance that has been reported in uremic patients on an LPD. An abnormal insulin sensitivity of EGP may participate in the disturbances of glucose metabolism in chronic renal failure.

Adult↗
PubMed1997

Cyclosporin-A- and angiotensin-II-induced vasoreactivity in isolated glomeruli and cultured mesangial cells, 4 and 24 h after renal mass reduction: role of vasodilatory prostaglandins.

Subtotal nephrectomy in the rat is followed by early hypertrophy and functional adaptation of the remnant glomeruli in which mesangial cells seem to play a leading part. Using a morphoquantitative approach, we assessed the vasoconstrictive response to 1 microM cyclosporin A (CsA) or 0.1 microM angiotensin II (AII) of isolated glomeruli and cultured mesangial cells obtained from normal rats and from rats after five-sixths nephrectomy. In normal rats, a significant reduction of glomerular size was observed after the administration of vasoactive agents (-14% after 30 min exposure to CsA or AII). After five-sixths nephrectomy the vasoconstrictive response, which was preserved at the 4th hour (-12% at the 30th minute), disappeared at the 24th hour (-1.5% at the 30th minute), but was maintained in animals pretreated with indomethacin (-10% at the 30th minute). Similar responses were observed with cultured mesangial cells at the first passage. Inhibition of prostaglandin synthesis abolishes the adaptative adjustments observed in partially nephrectomized rats during the first days after surgery. These findings suggest that renal vasodilatory prostaglandins may participate in the compensatory hemodynamic adjustments following subtotal nephrectomy.

Adaptation, Physiological↗
PubMed1997

Protective effect of three xanthine derivatives (theophylline, caffeine and pentoxifylline) against the cyclosporin A-induced glomerular contraction in isolated glomeruli and cultured mesangial cells.

Cyclosporin A (CyA), an immunosuppressive agent, induces in vivo a severe nephrotoxicity with large decrease in renal hemodynamics correlated with in vitro glomerular contraction. The aim of this study is to show the ability of three xanthine derivatives, caffeine, theophylline and pentoxifylline, to diminish the CyA-induced in vitro glomerular contraction. The use of isolated glomeruli and cultured rat mesangial cells permits us to evaluate by quantitative and qualitative morphometric analysis the contraction elicited either with CyA alone or with previous treatment with nontoxic concentrations of xanthine derivatives. Indirect immunofluorescence of actin filaments makes it possible to appreciate qualitative morphometric changes in mesangial cells. A 10-min pretreatment with caffeine, theophylline or pentoxifylline (10(-4) to 10(-9) M) abolishes the contraction elicited with 10(-6) M CyA. CyA alone induces -13.9% compared to CyA with 10(-6) M pentoxifylline which induces only -3.2% of reduction of planar glomerulus surface area after 30 min. Similar results were provided with cultured rat mesangial cells. As shown by indirect immunofluorescence xanthine derivatives prevent the cytoskeletal reorganization (alpha-actin) of cultured mesangial cells which occurs with CyA. The marked constriction induced by CyA in isolated glomeruli and mesangial cells can be prevented by xanthine derivatives.

Animals↗
PubMed1996

Sporadic MERRF/MELAS overlap syndrome associated with the 3243 tRNA(Leu(UUR)) mutation of mitochondrial DNA.

We studied a patient with a mitochondrial encephalomyopathy characterized by the presence of all the cardinal features of both myoclonic epilepsy and ragged-red fibers (MERRF) and mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS) syndromes. Muscle biopsy showed ragged-red fibers (RRF). Some RRF were cytochrome c oxidase (COX)-negative while some others stained positive for COX. Muscle biochemistry revealed defects of complexes I and IV of the respiratory chain. Both muscle and blood mitochondrial DNA from the patient showed the presence of the mutation at nucleotide position 3243 in the tRNA(Leu(UUR)) gene and the absence of point mutations related to MERRF syndrome. The proportions of mutant mtDNA were 70% in muscle and 30% in blood. The mutation was absent in blood from all maternal relatives, in hair follicles from the mother, and in muscle from one sister of the proband. Therefore, there was no evidence of maternal inheritance.

Adolescent↗
PubMed1996

[Rheumatoid purpura in adults. Apropos of 40 cases].

Fourty cases of Henoch-Schönlein purpura in adults (21 females, 19 males--age 39 years) are reviewed [departments of nephrology (28 cases) and internal medicine (12 cases)]. Dermatological manifestations occur in 39 cases and are similar to those seen in children. Gastrointestinal involvement (23 cases) usually takes the form of abdominal pains or diarrhea; gastrointestinal haemorrhages are rare. These symptoms are less severe than in children in this review as in the literature. Joint manifestations (22 cases) disappear without sequelae. The outcome of the disease depends on the nephropathy, present in 33 patients (82.5%) (all of those of the department of nephrology (100%) and 42% of those of the department of internal medicine). In one third of cases, renal manifestation appears after the onset of the disease (until 24 months). As in the children, haematuria and proteinuria are quasi constant. The renal histopathology is a focal and segmental proliferative glomerulonephritis in 58%, with IgA deposition in the mesangium (16/21 cases). Treatment regimen includes steroïds (10 cases), combination of steroïds with immunosuppressive agents (8 cases), steroïds-immunosuppressive drugs-plasma exchange (2 cases), dapsone (1 case). Of the 26 patients followed for 27 months, 11 are in clinical remission, 7 have persistent proteinuria or hematuria, and 8 have chronic renal failure after 3 months to 13 years. In this review, renal insufficiency, hypertension and young age predict a poor outcome. This severe outcome is probably explained by the fact that most of our patients referred to renal units. Unlike in the children, in which the affection is usually an acute illness, Henoch-Schönlein purpura in the adults seems to be a chronic disease, with prognosis depending on the nephropathy.

Adolescent↗
PubMed1996

Improvement in lipid profiles and triglyceride removal in patients on polyamide membrane hemodialysis.

Cardiovascular morbidity and mortality in hemodialyzed patients are increased due to the frequently abnormal lipid metabolism. It has been reported that this abnormal lipid metabolism could be partially corrected by some highly permeable membranes, such as polysulfone or cellulose triacetate. We investigated the influence of 4 months of dialysis with a polyamide membrane upon the course of lipid parameters in 6 patients presenting a hypertriglyceridemia > 2 mmol/l while on bicarbonate dialysis with a cellulose membrane. Lipid parameters improved after 4 months of hemodialysis with a polyamide membrane. Serum triglyceride and cholesterol levels decreased, while HDL cholesterol and HDL levels rose significantly (p < 0.05). Apolipoprotein B decreased significantly (p < 0.05). Following heparin administration, lipoprotein lipase activity improved (p < 0.02), associated with a decrease apolipoprotein C3 (p < 0.05). The fractional clearance rate of triglycerides rose significantly (p < 0.01). The use of highly permeable polyamide membranes results in a significant improvement in lipid disturbances of dialysis patients due to an increased lipoprotein lipase activity, induced perhaps by the removal of circulating inhibitors such as apolipoprotein C3.

Apolipoproteins↗
PubMed1996

[Role of phosphorus in hyperparathyroidism secondary to non-dialysed adult chronic renal insufficiency].

Secondary hyperparathyroidism (HPT II) occurs early in the course of chronic renal failure (CRF), mainly because of decreased calcitriol levels, low levels of serum calcium, retention of phosphorus, abnormal parathyroid gland function and hyperplasia, and peripheral resistance to the action of parathormone (PTH). Amongst these factors, phosphorus retention plays a crucial role in moderate and advanced CRF, by inhibiting renal calcitriol synthesis, lowering serum calcium levels and stimulating PTH secretion. In patients with mild CRF, phosphorus restriction prevents the development of HPT II by increasing renal calcitriol secretion. In patients with advanced CRF, the suppressive effect of phosphorus restriction may be obtained independent of any changes in plasma calcitriol levels, suggesting a direct effect of phosphorus on parathyroid function. Phosphorus restriction should be used in the early stages of CRF, together with a sufficient intake of calcium in the form of phosphorus chelating salts. When phosphorus and calcium serum concentrations are normalised but PTH levels are not in the target range, 1 alpha hydroxy vitamin D3 derivatives may be used, with a careful monitoring to avoid high serum levels of phosphorus or calcium.

Adult↗
PubMed1995

Variable clinical and biochemical presentation of seven Spanish cases with glutaryl-CoA-dehydrogenase deficiency.

In this report, we describe seven new patients with a severe deficiency of glutaryl-CoA dehydrogenase in cultured skin fibroblasts. Three of the patients studied excreted high levels of glutaric acid. The remaining four patients presented a lack of significant glutaric aciduria. However, glutaric acid was found in increased levels in CSF. In both groups of patients, the urine glutaric acid levels were not related to their metabolic condition at the time of sampling. Hypocarnitinemia was a common finding. Some patients also showed defects on respiratory chain complexes in muscle biopsy. Only one patient has a normal psychomotor development. The other six patients are severely handicapped despite the attempts of different therapies. In patients with progressive neurological deterioration with dystonia and cerebellar signs associated with temporal lobe atrophy and bilateral basal ganglia damage on MRI, a glutaric aciduria type I (GA I) should always be investigated. The presence of glutaric acid in body fluids, especially in CSF, as well as plasma carnitine levels, should be determined. These procedures can lead to the diagnosis of glutaric aciduria type I.

Brain↗
PubMed1995

Evaluation of red blood cell lipoperoxidation in hemodialysed patients during erythropoietin therapy supplemented or not with iron.

To investigate the effects of erythropoietin (rHuEPO) therapy supplemented or not with iron on hemolysis in hemodialysed patients (HD) we evaluated lipoperoxidation (LPO) by assaying (i) the red blood cell (RBC) antioxidant enzymatic system including superoxide dismutase (SOD), glutathione peroxidase, and catalase (Cat), (ii) RBC polyunsaturated fatty acids (PUFA) and (iii) malondialdehyde (MDA). Group 1 included 12 HD patients, group 2 had 7 HD patients with iron supplementation, group 3 comprised 12 HD patients with rHuEPO therapy and group 4 included 9 HD patients with both iron and rHuEPO therapies. No LPO was found in group 1 as regards MDA and PUFA levels. However, SOD and Cat activities were significantly elevated as compared to controls (p < 0.001). In the second group, a significant decrease in PUFA percentage was observed, particularly in 20:4(n-6) and 22:4(n-6) (the main ones involved in LPO) as compared to the other groups, whereas total MDA level was higher than that of the other groups. Similarly a decreased SOD activity was observed as compared to group 1 (p < 0.001), indicating its inactivation subsequent to an hyperproduction of reactive oxygen species through iron injection. In groups 3 and 4 no change was observed in MDA levels or PUFA percentages indicating no LPO. However, marked differences were observed in the enzymatic defense system. Particularly in group 3, SOD and Cat activities decreased when compared to group 1 (p < 0.001) whereas the association of erythropoietin and iron (group 4) increased the three enzymatic activities (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Long-term control of hyperparathyroidism in advanced renal failure by low-phosphorus low-protein diet supplemented with calcium (without changes in plasma calcitriol).

Phosphorus (Pi) retention linked to chronic renal failure (CRF) favors secondary hyperparathyroidism (HPT). Reduction of Pi and protein intake has been shown to prevent the development of HPT in CRF. The aim of the present study was to assess in patients with advanced CRF the long-term effects on phosphate and calcium metabolism of a low-Pi (5-7 mg/kg/day), low-protein (0.4 g/kg/day) diet providing 300 mg/day calcium (Ca) and supplemented with amino acids and ketoacids, Ca carbonate (400-800 mg/day) and vitamin D2 (1,000 IU/day). Twenty-nine patients with advanced CRF (glomerular filtration rate (GFR) 13.7 +/- 4.5 ml/min) were selected for the study, on the basis of a follow-up of a least 2 years and a satisfactory compliance to the prescribed diet. At the start of the study, biological evidence of HPT was present with increased plasma PTH concentration (144 +/- 95 pg/ml), increased plasma Pi (1.57 +/- 0.33 mmol/l), an increase in alkaline phosphatase activity and plasma osteocalcin concentration. Plasma PTH concentration was positively correlated with plasma Pi and inversely with plasma Ca concentrations and GFR. Pi and protein restriction induced a significant correction of HPT within 3 months after starting the diet. After 2 years of diet, despite the diminution of GFR (11.1 +/- 3.7 ml/min, p < 0.0001), plasma PTH was still lower than at the start of the diet (88 +/- 57 pg/ml, p < 0.01), as was plasma Pi (1.32 +/- 0.24 mmol/l, p < 0.001), total plasma Ca being higher (p < 0.01). Plasma PTH levels were correlated only to plasma Ca concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Correction of chronic metabolic acidosis in haemodialysed patients by acetate-free biofiltration does not influence parathyroid function.

In eight patients remaining acidotic after more than 1 year of bicarbonate haemodialysis, we studied the effect of correcting the chronic metabolic acidosis using acetate-free biofiltration for 4 months on the course of secondary hyperparathyroidism. An AN69 capillary membrane was employed with a bicarbonate infusion rate initially set at 1.8 l/h in all patients and then adjusted in each one to obtain a predialysis bicarbonate of > or = 23 mmol/l. Standard blood chemistry parameters were determined every 2 weeks. Measurements of PTH, calcifediol and calcitriol, as well as calcium-PTH curves were determined at the beginning and end of the study. While acetate-free biofiltration appears to be an adequate technique for the correction of chronic metabolic acidosis when bicarbonate dialysis fails, this study indicates that it does not influence secondary hyperparathyroidism in haemodialysed patients. The level of intact PTH did not vary significantly and the calcium-PTH curves at 0 and 4 months were superimposable with no significant differences in the set point and the slope of the curves.

Acidosis↗
PubMed1995

[Nutrition and continuous ambulatory dialysis].

Nearly 50% of patients treated by CAPD develop a more or less severe state of denutrition with which morbidity and mortality are closely linked. Though many biological and biophysical examinations have been proposed to evaluate the nutritional status of patients, it appears that, from a practical standpoint, the information furnished by the medical history, anthropometric parameters, nitrogen balance and serum protein levels are sufficient. The prevention and/or treatment of this malnutrition can only be achieved by correcting the two principal contributing factors which are the reduced energetico protidic supply (especially protidic) and the inadequate dialysis in connection particularly with the progressive loss of the residual renal function.

Blood Proteins↗
PubMed1995

Clinical evaluation of an optimized 1.1% amino-acid solution for peritoneal dialysis.

A significant percentage of dialysed patients have inadequate protein intake. One strategy for treating the protein malnutrition in peritoneal dialysis patients is to replace glucose in the dialysis solution by amino acids. A new peritoneal dialysis solution containing 1.1% amino acids in a formulation optimized for renal patients and with a lactate concentration of 40 mmol/l has been evaluated. Fifteen CAPD patients completed a non-randomized prospective 3-month study. Each patient received 2 litres of the optimised 1.1% amino acid solution for the second exchange of the day with a dwell time of 5-6 h. Indicators of efficacy were serum albumin and transferrin. After 3 months of intraperitoneal amino acids, serum albumin levels significantly increased from 32.7 +/- 2.3 to 35.1 +/- 2.2 g/l (mean +/- SD; P < 0.01). This occurred in parallel with a significant increase in transferrin levels from 2.21 +/- 0.26 to 2.39 +/- 0.27 g/l (P < 0.05). As expected, urea rose from 23.7 +/- 6.8 to 29.9 +/- 9.4 mmol/l. Interestingly bicarbonate did not change (25.5 +/- 4.2 versus 25.2 +/- 3.3 mmol/l). These results suggest that the optimized formulation is effective in improving nutritional parameters in CAPD patients while avoiding unwanted side-effects such as acidosis.

Adult↗