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B Marrón

Publications and source records attributed to B Marrón.

17 recordsLinked to original sources
PubMed2001

[Calciphylaxis: an uncertain pathogenesis and controversial treatment].

Calciphylaxis is an uncommon but serious disease process that affects mainly patients with advanced renal failure. Calciphylaxis is characterized by dermal arteriolar calcification that leads to skin ulceration, necrosis, ischemia and secondary infection. The pathogenesis is poorly understood, although the calcium phosphorus product has been proposed as a major cause. Given the high morbidity and mortality rate, emphasis should be placed on prevention and early diagnosis of vascular calcification, as well as in prophylaxis of secondary infection. We present changing concepts in four patients receiving dialysis.

Aged↗
PubMed1999

Angiotensin-converting enzyme is upregulated in the proximal tubules of rats with intense proteinuria.

Persistent proteinuria is considered a deleterious prognostic factor in most progressive renal diseases. However, the mechanisms by which proteinuria induces renal damage remain undetermined. Since proximal tubular cells possess all the machinery to generate angiotensin II (Ang II), we approached the hypothesis that proteinuria could elicit the renal activation of the renin-angiotensin system in a model of intense proteinuria and interstitial nephritis induced by protein overload. After uninephrectomy (UNX), Wistar-Kyoto rats received daily injections of 1 g BSA or saline for 8 days. The mean peak of proteinuria was observed at the fourth day (538+/-89 versus 3+/-1 mg/24 h in UNX controls; n=12; P<0.05) and was increased during the whole study period (at the eighth day: 438+/-49 mg/24 h; n=12; P=NS). Morphological examination of the kidneys at the end of the study showed marked tubular lesions (atrophy, vacuolization, dilation, and casts), interstitial infiltration of mononuclear cells, and mesangial expansion. In relation to UNX control rats, renal cortex of BSA-overloaded rats showed an increment in the gene expression of angiotensinogen (2.4-fold) and angiotensin-converting enzyme (ACE) (2.1-fold), as well as a diminution in renin gene expression. No changes were observed in angiotensin type 1 (AT1) receptor mRNA expression in both groups of rats. By in situ reverse transcription-polymerase chain reaction and immunohistochemistry, ACE expression (gene and protein) was mainly localized in proximal and distal tubules and in the glomeruli. By immunohistochemistry, angiotensinogen was localized only in proximal tubules, and AT1 receptor was localized mainly in proximal and distal tubules. In the tubular brush border, an increase in ACE activity was also seen (5. 5+/-0.5 versus 3.1+/-0.7 U/mg protein x10(-4) in UNX control; n=7; P<0.05). Our results show that in the kidney of rats with intense proteinuria, ACE and angiotensinogen were upregulated, while gene expression of renin was inhibited and AT1 was unmodified. On the whole, these data suggest an increase in Ang II intrarenal generation. Since Ang II can elicit renal cell growth and matrix production through the activation of AT1 receptor, this peptide may be responsible for the tubulointerstitial lesions occurring in this model. These results suggest a novel mechanism by which proteinuria may participate in the progression of renal diseases.

Animals↗
PubMed1996

Double renal transplant from infant donors. A good alternative for adult recipients.

Several groups have reported technical complications and poor graft survival rates in kidney transplants from pediatric donors to adult recipients. Increased incidences of acute rejections, vascular thrombosis, and early glomerulosclerotic lesions have led many groups to abandon this graft combination. Over the last 4 years, we have set up a program of two-kidney transplantation from cadaveric infant donors under age 3 years, which to date includes 15 adult recipients. Thirteen of these grafts are currently functioning at least as well as those from adult donors, after a mean follow-up of 1.5 years. Our surgical and therapeutic procedures have led to a minimization of the early complications reported by other groups. With this transplantation procedure, the patients receive double the number of nephrons, which will probably give them better long-term function. The encouraging results achieved by our group may help change the current consideration of pediatric donors as "suboptimal" ones.

Adolescent↗
PubMedDate not supplied

[Peritoneal equilibrium test with hypertonic exchange: practical application in a peritoneal dialysis program].

Peritoneal equilibration test (PET) employing a 2.27%/2.5% glucose exchange is the most widely used method of to evaluating peritoneal function and small solute transport. Hypertonic (3.86%/4.25% glucose) PET has been recently recommended for the evaluation of ultrafiltration and to study certain causes of ultrafiltration failure, such as aquaporin dysfunction, through the analysis of dialysate sodium. However, there is not enough information on the optimal way to express the changes in dialysate sodium concentration, the normal range of values for this parameter, and possible adverse effects of hypertonic PET in the general population of peritoneal dialysis patients. A hypertonic PET was performed in 22 patients. Ultrafiltration failure (ultrafiltration < 0.4 L) was present in seven patients. Patients with ultrafiltration failure had higher small solute peritoneal transport and dialysate sodium concentration and had been treated with peritoneal dialysis for longer periods of time. Dialysate sodium concentration at 60 and 240 minutes was directly correlated with small solute peritoneal transport calculated as D/PCr240 (r = 0.74, p = 0.0008 y r = 0.84, p < 0.0001) and inversely correlated with ultrafiltration (r = 0.64, p = 0.0016 y r = 0.72, p = 0.0002). An absence of a dip in dialysis sodium, suggestive of aquaporin dysfunction, was only observed in one patient with a high-average small solute peritoneal transport. Dialysate sodium concentration at 60 minutes is a better discriminator between ultrafiltration failure patients than parameters such as D/PNa or the absolute dip in dialysate sodium with respect to time zero. We observed the following adverse effects: symptomatic hypotension in 2 patients with preserved ultrafiltration. In conclusion, hypertonic PET allows to confirm the diagnosis of ultrafiltration failure, but monitoring dialysate sodium concentration offers additional information only in patients with severe aquaporin dysfunction. Hypertonic PET may have adverse effects in patients without ultrafiltration failure.

Adult↗