PubMed Health⌕ Search

Biomedical subjects

A Argiles

Publications and source records attributed to A Argiles.

30 records · Page 2Linked to original sources

Acute adaptative changes to unilateral nephrectomy in humans.

Renal function was monitored in 20, living-related kidney donors before and after uninephrectomy. Urinary protein excretion and retinoid metabolism respectively were studied in 10 and 6 of these donors. The functional adaptation was characterized by an increase in glomerular filtration rate and tubular function, which began in the first two days after uninephrectomy. Changes in tubular function were also demonstrated by significant increases in the urinary excretion of beta 2 microglobulin (beta 2M), retinol binding protein (RBP), kappa and lambda light chains of immunoglobulins. In addition, a protein identical to or homologous to cellular retinoic acid binding protein (CRABP), appeared in the urine after nephrectomy. We did not find CRABP in serum samples either before or after nephrectomy, suggesting that urinary CRABP was synthesized by the remaining kidney. Increases in serum levels of Vitamin A and RBP were also observed in the post-nephrectomy period. These modifications in retinol metabolism suggest that these substances could have a role as renotropic growth factors in compensatory hypertrophy.

Adult↗

Haemodialysis-associated amyloidosis: beta 2-microglobulin alone or associated with globin chains?

1. The protein constituents of amyloid fibrils were characterized in amyloid deposits extracted from surgical material obtained from a 66-year-old patient undergoing maintenance haemodialysis and operated for a carpal tunnel syndrome. 2. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis disclosed the presence of bands at 12 and 14 kDa. Two-dimensional electrophoresis and Western blotting confirmed that the proteins were beta 2-microglobulin (beta 2M) and globin chains. 3. When the effluent of high-performance gel filtration chromatography corresponding to molecular masses of 10-15 kDa was subjected to Edman degradation, only one amino acid residue was found at each step. The 18 residues determined corresponded to the N-terminal sequence of beta 2M. 4. Although globin chains were clearly present in the amyloid material, they were not accessible for sequence determination. The identification of the other protein constituents present in the amyloid material, along with beta 2M, should provide a better understanding of haemodialysis-associated amyloidosis, the mechanisms of formation of which have not yet been completely determined.

Aged↗

Hemodiafiltration using dialysate as substitution fluid.

To reduce the cost of hemodiafiltration (HDF), a standard hemodialysis machine was modified to permit in-line production of substitution fluid from bicarbonate dialysate. The authors' present data showing that this procedure was made bacteriologically safe; was simple to use, and offered a cheap approach to perform high-flux HDF using a hemodifilter of relatively small membrane surface area.

Bicarbonates↗

[Amyloid deposits in hemodialysis patients: immunochemical analysis].

We have analyzed 9 amyloid deposits isolated from 7 patients treated by long-term hemodialysis [6] and/or hemofiltration [1] for 8 to 19 years. Amyloid deposits were extracted from carpal tunnel synovitis [7] or femoral bone [2]. Proteins were analyzed by SDS-PAGE, two-dimensional electrophoresis and the identification was made by Western Blotting and specific antibody fixation. Several proteins were found: immunoglobulin light chains, beta 2 microglobulin (B2M), as well as globin chains, albumin and hemopexin. These findings suggest that amyloid deposits are not only made of B2M, but also with other protein species not cleared by dialysis membranes. Among these proteins, B2M and immunoglobulin light chains have well known amyloidogenic properties. We suggest that the role played by the remaining proteins on the pathogenesis of dialysis associated amyloidosis should also be considered.

Adult↗

[Hypertension and stenosis of the graft artery: effects of conversion enzyme inhibition].

The use of angiotensin converting enzyme inhibitors may lead to reversible renal insufficiency in transplant patients with transplant renal artery stenosis (TRAS). We assessed acute effects of captopril (50 mg, p. os) in 7 cadaver kidney recipients (mean age: 35.6 +/- 4 yrs) with TRAS, 9 to 46 mo after transplantation. All patients were treated by prednisolone and azathioprine. After captopril administration, mean arterial pressure decreased from 127 +/- 6 to 119 +/- 7 mmHg, effective renal plasma flow from 152 +/- 19 to 118 +/- 19 ml/min/1.73 m2, glomerular filtration rate from 59 +/- 8 to 39 +/- 10 ml/min/1.73 m2 and filtration fraction from 0.39 +/- 0.02 to 0.32 +/- 0.07. Among the 7 patients, 2 developed immediate and transient anuria; 4 presented a net decrease of GFR, only one had stable GFR. This patient was chronically treated by captopril; as BP was not controlled, furosemide (40 mg p. os) was added. Serum creatinine increased from 180 to 250 mumol/l. Percutaneous angioplasty was done without decrease in BP; however, treatment by captopril and furosemide could be reinstitued without deterioration in renal function. We conclude that: acute renal failure in kidney graft recipients with TRAS is frequent, but not mandatory; sodium depletion induced by diuretics enhances the fall in GFR; acute effect of captopril must be assessed in patients with TRAS before the use of this product as long term antihypertensive treatment.

Acute Kidney Injury↗

[Effect of inhibition of angiotensin converting enzyme on hypertension following kidney transplantation].

The activation of the renin angiotensin system is thought to be an important factor contributing to hypertension following kidney transplantation (TX). We studied 21 hypertensive renal transplant recipients, without evidence of acute graft rejection or transplant artery stenosis, 6 to 60 months post-TX. The acute responses of mean arterial pressure (MAP) and renal hemodynamics (ERPF: effective renal plasma flow, 131I-Hippuran clearance) and function (GFR: glomerular filtration rate, creatinine clearance; UNaV: urinary sodium excretion rate) to converting enzyme inhibition (CEI) by captopril were assessed. CEI induced a decrease in MAP (118 +/- 2 to 110 +/- 2 mmHg), renal resistance (RR: 0.27 +/- 0.02 to 0.21 +/- 0.01) and filtration fraction (FF: 0.31 +/- 0.02 to 0.23 +/- 0.01). ERPF (307 +/- 24 to 333 +/- 18 ml/min/1.73 m2) and GFR (88 +/- 5 to 78 +/- 5 ml/min/1.73 m2) were not significantly changed. UNaV increased by 53 +/- 24 mumol/min. Changes in MAP (r = -0.66), ERPF (r = 0.74) and FF (r = -0.88) were significantly correlated with the log of control plasma renin activity (PRA). In 10 patients with an increase of ERPF (range: + 30 to + 70%) and no change in GFR, the activated renin system could originate from the recipient's own kidneys. In the remaining 11 patients, CEI was associated with no increase in ERPF (change: + 2 to - 27%) and a fall in GFR, a response suggesting a possible intrarenal vascular damage. These results indicate that RAS participates in the regulation of systemic and renal vascular tone, with a possible predominant effect on efferent glomerular arteriole.

Adult↗

Protein catabolic rate determination from a single measurement of dialyzed urea.

Protein catabolic rate (PCR, in g protein/kg/day) for anuric patients can be accurately determined without blood sampling by equating urea generation over 7 days to the urea dialyzed in the three dialyses of this period as measured by partial dialysate collection (PDC) or with a urea monitor. The feasibility of determining the week's dialyzed urea from measurement of urea dialyzed in a single session, obviating the need to monitor three consecutive dialyses, was examined in a steady-state simulation of 540 anuric patients spanning the full range of dialysis parameters. It was found that the first, midweek, and last dialyses account for nearly constant fractions (37.9, 32.1, and 30.0%, respectively) of the week's urea removal, leading to equations of the form: PCR = CU/BW + 0.17 where U is the grams of urea dialyzed in the first, midweek, or final dialysis of the week, C = 2.45, 2.89, or 3.10, respectively, and BW is the patient's dry weight in kilograms. These equations were tested on 1312 weeks of PDC data gathered in 42 dialysis patients. Using the midweek U resulted in a mean absolute error in PCR < 0.05 g/kg/day when compared to PCR determined using all three of the week's U values.

Aged↗