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Biomedical subjects

A Andres

Publications and source records attributed to A Andres.

At least 73 records · Page 4Linked to original sources
PubMed1991

Tubular dysfunction in nephrotic syndrome: incidence and prognostic implications.

Although some cases of tubular dysfunction (TD) associated with nephrotic syndrome have been described, the incidence and the characteristics of this complication remain unknown. We investigated the presence of TD (renal glycosuria, aminoaciduria, metabolic acidosis with normal anion gap, hypouricaemia, and throughout hypophosphataemia) in 36 patients with nephrotic syndrome. Ten patients (group 1) showed glycosuria at some time during the course of their illness, ranging from 2.5 to 11.2 g/24 h. In addition, seven of them had metabolic acidosis with normal anion gap, five aminoaciduria, and two hypouricaemia. Membranous glomerulonephritis was the most frequent aetiology in group 1 patients (7 of 10). Proteinuria and serum creatinine (SCr) were significantly higher in group 1 patients than in the 26 remaining patients without TD (group 2): 10.2 +/- 3.7 versus 6.7 +/- 2.9 g/24 h (P less than 0.01) and 3.2 +/- 1.9 versus 1.6 +/- 0.9 mg/dl (P less than 0.05) respectively. The appearance of TD coincided with a clear worsening of renal function in most of group 1 patients. In addition, at the end of follow-up, SCr had increased from 3.2 +/- 1.9 to 5.6 +/- 3.3 mg/dl (P less than 0.05) in this group. In contrast, SCr did not show significant changes in group 2 (1.6 +/- 0.9 versus 2.1 +/- 2.2 mg/dl). In conclusion, a significant proportion (27.7%) of patients with nephrotic syndrome present TD data at some moment of their course; the appearance of this complication appears to be a sign of poor prognosis.

Adolescent↗
PubMed1991

Does calcium antagonist improve established early ciclosporin nephrotoxicity after renal transplantation?

We report a case of prolonged oliguric acute renal failure after renal transplantation under steroids and ciclosporin (Cs) immunosuppression. In the 2nd week when low fractional excretion of sodium values in the presence of oliguria (as expression of Cs nephrotoxicity) and high Cs blood levels were seen, a calcium antagonist drug was administered. Also, a Cs dose adjustment was made. Then, the diuresis and fractional excretion of sodium increased together with a progressive renal function. Although this evolution could be explained as a spontaneous resolution of postischemic renal failure, we speculated that in this case of established early Cs nephrotoxicity the effect of a calcium antagonist drug, such as nifedipine, could be beneficial.

Acute Kidney Injury↗
PubMed1989

Hematuria due to hypercalciuria and hyperuricosuria in adult patients.

We have prospectively studied 37 adult patients (15 males, 22 females; age 31 +/- 10.6 years) with previously undiagnosed isolated hematuria in which hypercalciuria or hyperuricosuria was found. Eighteen of them had had episodes of gross hematuria. Isolated hypercalciuria (4.4 to 10.4, X 5.6 +/- 1.9 mg/kg/24 hr) was found in nine patients (Group I), isolated hyperuricosuria (784 to 1500, X 1088 +/- 228 mg/24 hr) in 11 (Group II), and both hypercalciuria (4 to 8, X 4.9 +/- 1 mg/kg/24 hr) and hyperuricosuria (752 to 1476, X 1042 +/- 181 mg/24 hr) in 17 patients (Group III). Thiazide treatment for patients with hypercalciuria and allopurinol for those with hyperuricosuria were administered; calciuria and uricosuria became normal by the first month of therapy in every case. In 22 (59.4%) cases (Responder patients) hematuria resolved completely as soon as calciuria and uricosuria became normal. In the remaining 15 cases (Nonresponder patients) hematuria persisted despite the normal calcium and uric acid excretions. Several disorders that explained hematuria were diagnosed later in most of Nonresponder patients. Responder patients persisted without hematuria on the follow-up; only in three patients a transient relapse of hematuria was seen associated with a sudden increase of calciuria and uricosuria because of treatment withdrawal. There were no differences in age, male/female ratio nor in the basal values of calciuria and uricosuria between Responder and Nonresponder patients. A familial history of urolithiasis was found more frequently in Responder patients (64%) than in Nonresponders (20%) (P less than 0.05). We conclude that hypercalciuria and hyperuricosuria are definable and potentially reversible causes of hematuria in adult patients.

Adolescent↗
PubMed1987

Fractional excretion of sodium represents an index of cyclosporine nephrotoxicity in the early post-transplant period.

We reviewed the evolution of FENa in the EPP (first 4 weeks) in a group of CyA-treated patients as well as Aza-treated patients who did not present with acute rejection during this period of time. The CyA-treated patients showed lower values of FENa than did Aza-treated patients. Values of FENa below 1% were found in 51% of CyA- and 0% Aza-treated patients (P less than .01) before RFR. The finding of low FENa values was accompanied by more prolonged oliguric and RFR phases. Furthermore, the lower the level of FENa, the higher the prolongation of renal failure. We concluded that FENa values could probably be an index of CyA nephrotoxicity in the EPP.

Azathioprine↗
PubMed1986

Evidence for the presence of muscarinic acetylcholine receptors in bovine brain coated vesicles.

Evidence obtained from quinuclidinylbenzilate binding determinations suggested that muscarinic acetylcholine receptor molecules are present in purified bovine brain coated vesicles. Immunoprecipitates formed from coated vesicles with polyclonal antibodies to clathrin bound on the surface of fixed Staphylococcus aureus cells also showed quinuclidinylbenzilate binding activity. The high purity of coated vesicles was established by assays for biochemical markers and by electron microscopy. Muscarinic receptor sites for quinuclidinylbenzilate binding to coated vesicles displayed a Kd of 25 pM and a Bmax of about 191 fmol/mg of protein. Binding competition experiments using atropine, N-methylscopolamine, oxotremorine, and carbamylcholine confirmed the typical muscarinic nature of the binding site. Ranking order of potency for the receptors was: atropine greater than N-methylscopolamine greater than oxotremorine greater than carbachol Analysis of data using a two-site model revealed 13% high-affinity sites for oxotremorine, 66% high-affinity sites for carbachol, and 62% for the antagonist N-methylscopolamine. Heterogeneity of binding affinities for muscarinic drugs detected in the coated vesicles may be related to the presence of coated vesicle subpopulations in brain tissue, (Kohtz, D. S., Kohtz, J. D., Schook, W. J., and Puszkin, S. (1985) J. Cell Biol. 101, 48a; Pfeffer, S. R., and Kelly, R. B. (1985) Cell 40, 949-957).

Animals↗
PubMedDate not supplied

[Diabetes Type I therapy through transplantation].

Diabetes is one of the most common chronic diseases in our society. While insulin treatment for diabetes type I could delay and reduce the incidence of diabetic complications, it is associated with an increased risk of severe hypoglycemia. To restore physiologic insulin metabolism, transplantation of insulin producing cells (pancreatic Beta cells) represent the sole available therapy. It could be done either through pancreas or islet of Langerhans transplantation. In this paper, we review actual knowledge regarding these two types of transplantations.

Diabetes Mellitus, Type 1↗
PubMedDate not supplied

Phylogenetic disparity influences the predominance of direct over indirect pathway of antigen presentation in islet xenotransplantation.

BACKGROUND: Cellular immunity plays a major role in rejection of xenografted islets. Depending on the phylogenetical disparity, direct or indirect antigen presentation is predominant. The aim of this study was to analyze in vitro the predominance of direct or indirect presentation, and in vivo the effect of macrophage depletion on concordant and discordant islet xenograft survival. MATERIALS AND METHODS: In vitro, we performed mouse antirat and mouse antihuman mixed lymphocyte reactions (MLR) after depletion of responder or stimulator antigen-presenting cells. In vivo, streptozotocin-induced diabetic C57BL/6 mice were treated by gadolinium chloride to deplete macrophages and rat or human islets were transplanted under the kidney capsule. Islet function was followed by glycemia and xenografts were analyzed at regular intervals for histology. RESULTS: Mouse antirat MLR showed a predominant direct antigen presentation pathway, whereas in mouse antihuman MLR, direct and indirect pathways were similarly involved. Survival of rat islets was not modified by GdCl therapy. In contrast, survival of human islets was significantly prolonged in GdCl-treated mice. Macrophage infiltration was decreased in concordant and discordant GdCl-treated xenografts at day 4, compared to controls. At day 15, macrophage infiltration was similar in all groups. DISCUSSION: Our results indicate that direct antigen presentation is dominant in rejection of concordant islet xenografts and cannot be influenced by host macrophage depletion. Both direct and indirect antigen presentation are involved in rejection of discordant xenogeneic islets. Macrophage depletion or inhibition should be considered as therapeutic tool for discordant islet xenotransplantation.

Animals↗
PubMedDate not supplied

Role of CD40-CD154 pathway in the rejection of concordant and discordant xenogeneic islets.

BACKGROUND: Costimulatory blockade has been shown to allow long-term survival of xenogeneic islets. The aim of the present study was to evaluate the role of recipient CD40 and CD154 in the rejection process of concordant and discordant islet xenotransplantation (Tx). METHODS: Diabetic C57BL/6 mice, CD40- or CD154 knockout (KO) mice were transplanted with either concordant rat or discordant human islets. EXPERIMENTAL DESIGN: group 1, control (ie, C57BL/6 mice received islet Tx without therapy); group 2, C57BL/6 mice received islet Tx with anti-CD154 monoclonal Ab (mAb) therapy; group 3, CD40 KO mice; and group 4, CD154 KO mice were used as recipients without therapy. Mouse anti-rat mixed lymphocyte reactions (MLR) were performed using mouse splenocytes obtained from animals transplanted with rat islets in groups 1 to 4. RESULTS: In group 2, short-term anti-CD154 mAb therapy significantly prolonged rat-to-mouse and human-to-mouse xenograft survival, compared to controls. In CD40-KO and CD154-KO recipients, survival of concordant or discordant islets was not prolonged significantly compared to control groups. Mouse anti-donor rat cellular responses were reduced approximately 50% in group 2 but remained unmodified in groups 3 and 4, when compared to group 1. CONCLUSIONS: Improved graft survival and reduced MLR responses against donor cells in vitro among the anti-CD154 mAb-treated mice could be explained by specific targeting of activated T cells with subsequent inactivation by anergy and/or elimination by apoptosis, or complement- or cellular-mediated mechanisms. Rejection of xenografts and strong MLR responses against donor cells in vitro in CD40 or CD154 KO animals is possible through efficient activation of alternate pathways of costimulation.

Animals↗