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Alberto Barrientos

Publications and source records attributed to Alberto Barrientos.

17 recordsLinked to original sources
PubMed2006

Victims of cardiac arrest occurring outside the hospital: a source of transplantable kidneys.

BACKGROUND: The use of non-heart-beating donors could help shorten the list of patients who are waiting for a kidney transplant. Several reports describe acceptable results of transplantations from non-heart-beating donors who had in-hospital cardiac arrest, but few reports describe results of transplantations from non-heart-beating donors who had cardiac arrest that occurred outside of the hospital (Maastricht type I and type II donors). OBJECTIVE: To compare graft survival rates among patients receiving kidneys from heart-beating donors versus type I or type II non-heart-beating donors. DESIGN: Retrospective cohort study of transplantations performed from January 1989 to December 2004. SETTING: Kidney transplant program of a teaching hospital in Madrid, Spain. PATIENTS: 320 patients who received a kidney transplant from non-heart-beating donors (273 type I donors and 47 type II donors) and 584 patients who received a kidney transplant from heart-beating donors divided into 2 groups according to donor age (age <60 years [n = 458] and age > or =60 years [n = 126]). MEASUREMENTS: The primary outcome measure was graft survival. The median follow-up time was 68 months (range, 9 to 198 months). RESULTS: One- and 5-year graft survival rates were 90.7% and 85.5%, respectively, for transplants from heart-beating donors younger than 60 years of age; 79.8% and 73.3%, respectively, for transplants from heart-beating donors 60 years of age or older (P < 0.001); and 87.4% and 82.1%, respectively, for transplants from non-heart-beating donors (P = 0.22 [vs. those from heart-beating donors < 60 years of age] and P = 0.014 [vs. those from heart-beating donors >or = 60 years of age]). Graft survival did not differ between patients who received kidneys from heart-beating donors younger than 60 years of age and patients who received kidneys from non-heart-beating donors. LIMITATIONS: This single-site, observational study was retrospective, and immunosuppressive therapy regimens given to transplant recipients varied over time. CONCLUSIONS: Outcomes of transplants from non-heart-beating donors and younger heart-beating donors are similar, and results for transplants from non-heart-beating donors improved compared with those from older heart-beating donors. On the basis of these results, the authors encourage other transplant units to adopt the use of type I and type II non-heart-beating donors.

Adult↗
PubMed2005

Endothelial hypoxic preconditioning in rat hypoxic isolated aortic segments.

Our aim was to analyse endothelial hypoxic preconditioning after hypoxia-reperfusion (HR). Endothelial functionality was analysed through the vasorelaxation responses to acetylcholine (Ach) and the level of serine1177 phosphorylated endothelial nitric oxide synthase (eNOS) (ser1177-eNOS) measured by Western blot in in vitro hypoxic preconditioned (P + HR) isolated rat aortic segments. Relaxation in response to Ach was reduced in phenylephrine-precontracted aortic segments after HR (control: IC50, 5 +/- 2.5 x 10(-8) mol l(-1); HR: IC50, 3 +/- 1.2 x 10(-7) mol l(-1); P < 0.05). Ach-dependent vasodilatation was improved by P + HR. The content of ser1177-eNOS in the HR segments was 1.5-fold lower than in P + HR. Confocal microscopy showed an increased content of both superoxide anion and peroxynitrite in the vascular wall of HR aortic segments, which it was reduced by P + HR. Geldanamycin (10 microg ml(-1)), an agent known to inhibit heat shock protein 90 (hsp90), reduced the level of ser1177-eNOS in P + HR aortic segments. However in the presence of geldanamycin, endothelial hypoxic preconditioning persisted. We conclude that short periods of hypoxia induced endothelial hypoxic preconditioning that was accompanied by enhanced levels of ser1177-eNOS in the vascular wall. The fact that endothelial hypoxic preconditioning persisted in the presence of geldanamycin suggests that other molecular mechanisms are involved in the endothelial adaptation to HR injury.

Acetylcholine↗
PubMed2005

Renal variant of Anderson-Fabry disease and bilateral renal cell carcinoma.

Anderson-Fabry disease (AFd) is an X-linked metabolic disease with clinical manifestations secondary to accumulation of glycosphingolipids in various tissues. We report the first case in which a patient with renal variant of AFd and chronic renal failure developed bilateral conventional renal cell carcinoma. His metabolic disorder was diagnosed only after histopathologic study of the kidney specimen resected because of the tumoral lesion. There is no clear etiologic relation between the metabolic and neoplastic disease. As AFd is not common or well known and its clinical manifestations tend to be nonspecific, the disorder is often unrecognized, misdiagnosed, or diagnosed late in life. The pathologist should be aware of this disorder when evaluating a kidney specimen from patients with chronic renal failure of unknown cause.

Aged↗
PubMed2005

Expression of adhesion molecules and RANTES in kidney transplant from nonheart-beating donors.

The main difference between cadaveric kidneys from donors with a heartbeat (HBD) and kidneys from nonheart-beating donors (NHBD) is related to warm ischemia/reperfusion time which constitutes an acute inflammatory process. On the contrary, brain death induces in HBD expression of pro-inflammatory adhesion molecules, making it important to evaluate this kind of molecules in both types of donors. Human renal biopsies from NHBD, HBD and normal kidneys (ischemia time = 0) were taken and frozen just before transplant. A semi-quantitative RT-PCR method was used to determine intracellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), lymphocyte function associated antigen (LFA-1), LFA-3, CD40, CD40 ligand (CD40L) and RANTES (regulated upon activation, normal T-cell expressed and secreted) gene expression. We have detected an elevated relative gene expression of ICAM-1, VCAM-1 and RANTES in NHBD biopsies compared with normal kidneys. In the case of RANTES, the gene expression from NHBD biopsies was higher than observed in HBD biopsies. The rest of genes were not augmented in any group. Preliminary data about early outcome of transplants indicates a correlation between pretransplant RANTES high gene expression levels and early post-transplant acute rejection. The gene expression of pro-inflammatory molecules like adhesion molecules and RANTES is augmented in kidneys from cadaveric NBD just before transplant. The expression is higher probably because of the prolonged warm ischemia period. A larger clinical study is necessary to clarify the effects of these variable expressions on the transplant outcome.

Adult↗
PubMed2005

Use of different immunosuppressive strategies in recipients of kidneys from nonheart-beating donors.

In nonheart-beating donor (NHBD) kidney transplants, immunosuppressive management is difficult mainly because of the high incidence of acute tubular necrosis. This has meant that since the start of our NHBD transplant program, several immunosuppression regimes have been used. The aim of this retrospective study was to evaluate the results obtained over 7 years using different treatment protocols. A total of 172 consecutive NHBD transplants performed between April 1996 and December 2002 were treated as follows: G-I (n = 21), cyclosporine (8 mg/kg/day) plus azathioprine plus steroids; G-II (n = 65), low-dose cyclosporine (5 mg/kg/day) plus mycophenolate plus steroids; G-III (n =17), low-dose tacrolimus (0.1 mg/kg/day) plus mycophenolate plus steroids; and G-IV (n = 69), daclizumab plus low-dose tacrolimus plus mycophenolate plus steroids. Delayed graft function rates were 76.2%, 72.3%, 76.5%, and 42%, respectively, for the four groups (P = 0.000). Rejection-free patient rates were 76.2%, 46.2%, 35.3%, and 71% (P < 0.001). Vascular rejection rates were 19%, 30.8%, 52.9%, and 18.8%, (P = 0.025). Two-year graft survival was 71.4% in group I, 95.4% in group II, 94.1 in group III, and 93.8% in group IV (P =0.004). Patient survival was worse in group I (75.2% in group I, 100% in group II, 100% in group III, and 96.7% in group IV at 2 years; P < 0.001). The use of daclizumab and low-dose tacrolimus could be effective at lowering the incidence of delayed graft function in NHBDT, with no negative repercussions on acute rejection.

Adult↗
PubMed2004

Does donor brain death influence acute vascular rejection in the kidney transplant?

BACKGROUND: There is increasing experimental evidence to suggest that donor brain death enhances susceptibility to early inflammatory responses such as acute rejection in the kidney transplant. The aim of the present study was to establish whether the injury induced or aggravated by donor brain death could exert an effect on recipient immunologic tolerance by comparing data from patients receiving a kidney from non-heart-beating donors (NHBD) or from brain-dead donors (BDD). METHODS: We reviewed data corresponding to 372 renal transplants performed from January 1996 to May 2002. The data were stratified according to donor type as 197 (53%) brain-dead and 175 (47%) non-heart-beating donors, and the two groups were compared in terms of acute vascular rejection by Cox's regression analysis. RESULTS: The rate of vascular rejection was 28% in the BDD group and 21.7% in the NHBD (P=0.10). The following predictive variables for acute vascular rejection were established: brain death [RR 1.77 (95% CI 1.06-3.18)], presence of delayed graft function [RR 3.33 (1.99-5.55)], previous transplant [RR 2.35 (1.34-4.13)], recipient age under 60 years [RR 1.86 (0.99-2.28)], female recipient [RR 1.50 (0.99-2.28)], cerebrovascular disease as cause of donor death [RR 1.72 (1.02-2.91)], and triple therapy as immunosuppressive treatment. CONCLUSION: Donor brain death could be a risk factor for the development of vascular rejection in kidney recipients. This process could affect the quality of the graft and host alloresponsiveness. Delayed graft function in transplants from dead brain donors could be a reflection of severe autonomic storm, leading to a higher incidence of vascular rejection in these patients.

Acute Disease↗
PubMed2003

Increasing the donor pool using en bloc pediatric kidneys for transplant.

OBJECTIVES: En bloc pediatric kidney transplants (EBPKT) are still a subject of controversy. The aim of this study was to determine whether acceptable long-term graft survival and function can be achieved in EBPKT compared with the transplant of single, cadaveric, adult donor kidneys. METHODS: A retrospective review was conducted of 66 recipients of en bloc kidneys from cadaveric pediatric donors and 434 patients who underwent transplantation with a single kidney from an adult donor between January 1990 and May 2002 at the authors' hospital. The recipients were well-matched demographically. Both transplant groups were analyzed for short- and long-term performance in terms of transplant outcome and quality of graft function. RESULTS: Overall death-censored actuarial graft survival rates at 1 and 5 years were 89.2% and 84.6% in the adult kidney transplants (AKT) and 83.3% and 81.1% in EBPKT, respectively (P=0.56). In the EBPKT group, graft function was improved over that observed in AKT. Vascular thrombosis was the most common cause of graft loss in EBPKT. Acute rejection occurred more frequently in AKT and Cox's regression analysis indicated that undergoing an AKT was a predictive factor for acute vascular rejection (adjusted risk ratio, 3.8; 95% confidence interval, 1.4-10.2; P=0.001). CONCLUSIONS: Overall graft survival was similar in both groups, vascular complications were the main cause of graft loss in EBPKT, and the EBPKT showed excellent long-term graft function and a low incidence of acute rejection.

Adolescent↗
PubMed2003

Epstein-Barr virus latency in kidney specimens from transplant recipients.

BACKGROUND: Epstein-Barr virus (EBV) infection is common in immunosuppressed patients and can lead to life threatening lymphoproliferative diseases. Small numbers of cells infected by EBV have been detected in human tissues, transplanted or non-transplanted. Little is known about EBV latency in the allograft kidneys of patients without post-transplant lymphoproliferative disease (PTLD). The aims of this study were to look for the presence of EBV-encoded small RNAs (EBER) in allograft kidneys and to quantify their expression. METHODS: We analysed 62 allograft nephrectomies and 20 native kidneys to determine the presence of EBV; we also quantified its expression and calculated its ratios to CD45 and CD20 cells. The techniques used were: tissue microarray, EBER-1- and 2-specific in situ hybridization and immunohistochemistry. RESULTS: EBER expression was detected in 30.6% of transplanted kidneys and 5% of non-transplanted kidneys. In the positive specimens, a mean of 8.2 cells/1.57 mm(2) expressed the EBERs (range 1-38 cells). The ratios of EBER-positive (+) cells to CD45 or CD20 cells were 1.7 +/- 2.4% (range 0.1-8.1%) and 8.4 +/- 10.9% (range 0.5-34.4%), respectively. No relationship was found between anti-T-cell treatment and EBER expression in the failed allografts. CONCLUSIONS: In failed kidney allografts, a small number of lymphocytes can express EBV latency. The number of EBER+ cells is smaller than in PTLD. Studies of functioning grafts are necessary to better understand the clinical relevance of this expression.

Adult↗
PubMed2003

Lead-induced downregulation of soluble guanylate cyclase in isolated rat aortic segments mediated by reactive oxygen species and cyclooxygenase-2.

Lead exposure is a known cause of hypertension. Although most studies have focused on lead-induced endothelial dysfunction and on the involvement of reactive oxygen species (ROS), it has been recently demonstrated that the vascular wall of lead-exposed rats has both an altered the endothelium-independent relaxing response and a reduced expression of soluble guanylate cyclase (sGC). The aim of the present study was to determine in in vitro incubated rat isolated aortic segments if lead downregulates sGC expression, analyzing the involvement of ROS and cyclooxygenase-2 (COX-2). The experiments were performed in isolated aortic segments from Wistar rats that were incubated with lead for 24 h. Lead significantly reduced sGC-beta(1) subunit expression in a concentration-dependent manner. The maximal reduction in sGC-beta(1) subunit expression was achieved with 1 ppm lead. Vitamin C (30 micromol/L) partially restored sGC-beta( 1) subunit expression in lead (1 ppm)-exposed aortic segments. A similar protection of sGC-beta(1) subunit expression was obtained with both a protein kinase A inhibitor, H89 (1 micromol/L) and with rofecoxib (1 micromol/L), an inhibitor of COX-2 activity. Moreover, lead exposure increased COX-2 expression in the arterial wall. While vitamin C reduced both COX-2 expression and superoxide anion production related to lead exposure, rofecoxib failed to modify superoxide anion generation in lead-incubated aortic segments. In conclusion, the present results suggest the involvement of ROS and COX-2 in the downexpression of sGC-beta(1) subunit induced by lead in the rat vascular wall.

Animals↗
PubMed2002

Erythrocyte aminolevulinate dehydratase activity as a lead marker in patients with chronic renal failure.

BACKGROUND: Overexposure to lead may result in an increased risk for developing chronic renal failure (CRF) and hypertension. Subclinical lead poisoning is difficult to identify. Because the heme biosynthetic pathway is highly sensitive to lead, we considered the study of enzymes involved in this pathway as a method to detect an excessive body lead burden. METHODS: Main concerns in assessing the heme pathway in patients with CRF were related to aminolevulinate dehydratase (ALAD) activity. We first selected a number of patients with CRF at a predialysis stage, subsequently dividing them into two groups after the EDTA mobilization test had determined whether lead pools were expanded. The study included 24 healthy controls, 12 patients with clinical plumbism and biochemical demonstration of lead poisoning (Pb-CONT), 18 patients with CRF with no evidence of high lead storage (CRF/-), and 8 patients with CRF with high urinary excretion of lead in contrast to normal blood lead levels (CRF/+). RESULTS: As expected, symptoms of plumbism (Pb-CONT) were accompanied by an increased erythrocyte zinc-protoporphyrin-free protoporphyrin ratio and high urine coproporphyrin excretion, whereas both these values were within the normal range in all patients with CRF. CRF/- patients showed minor abnormalities of erythrocyte heme metabolism, such as low ALAD activity, both baseline and in vitro restored. The ALAD-restored ALAD ratio correlated closely with urine lead excretion; it was normal in healthy controls and CRF/- patients and significantly reduced in Pb-CONT and CRF/+ patients. CONCLUSION: The erythrocyte ALAD-restored ALAD ratio may be a useful tool to show otherwise subclinical lead poisoning in patients with CRF.

Adult↗
PubMed2002

Lead mobilization during calcium disodium ethylenediaminetetraacetate chelation therapy in treatment of chronic lead poisoning.

It has long been established that chronic lead (Pb) poisoning is a cause of renal insufficiency. However, although easily diagnosed, there is still no treatment available that will revert this type of poisoning. We report a study performed on 56 male Wistar rats administered Pb in drinking water (500 ppm Pb acetate) over a 90-day period. Twenty-one non-Pb-exposed animals served as the control group. Seven animals from each group were killed days 60 and 90. At the end of the 90-day period, 21 of the Pb-exposed animals were treated with disodium monocalcium EDTA (50 mg/kg/d for 5 days) intraperitoneally and 21 animals were administered serum saline by the same route. Three treatment courses were administered, separated by 9 days free of treatment. Seven animals from each subgroup were killed at the end of each treatment course. Pb levels were determined in blood, urine, liver, brain, kidney, and bone. Treatment with EDTA led to a greater and more rapid reduction in Pb contents in the brain and kidney. The decrease in hepatic Pb levels in the treated group of animals was similar to that in the group administered placebo. Bone Pb levels also failed to show a response to the chelating agent. Use of EDTA appears to result in a reduction in Pb deposits in such critical organs as the kidney and brain. However, the chelating agent does not seem to have access to bone Pb deposits, such that the skeleton becomes a permanent source of poisoning for other tissues.

Animals↗
PubMed2002

Experimental lead nephropathy: treatment with calcium disodium ethylenediaminetetraacetate.

Chronic lead poisoning may cause hypertension, gout, and renal insufficiency. Most experimental poisoning studies have involved the use of high doses over short periods (ie, acute poisoning). Although chelating treatment leads to remission of acute lead nephropathy, its effects in the treatment of chronic poisoning are unclear. The aims of this study were to evaluate renal alterations produced during chronic lead poisoning and their progression when poisoning was over and to determine the efficiency of chelating treatment with calcium disodium ethylenediaminetetraacetate (EDTA). In this study, 56 male Wistar rats were administered lead in drinking water (500 ppm lead acetate) over 90 days. The control group consisted of 21 nonexposed rats. Seven rats from each group were killed on days 60 and 90. At the end of the 90-day period, 21 of the lead-exposed rats were treated with disodium monocalcium EDTA (50 mg/kg/d x 5 days) intraperitoneally, and 21 were administered serum saline by the same route. Three treatment courses were given separated by 9 days free of treatment. Seven rats from each subgroup were sacrificed at the end of each treatment course. Main findings related to poisoning were hypertrophy and vacuolization of medium and small arteries; mucoid edema and muscular hypertrophy in arterioles; loss of cell brush borders, cell loss, and intranuclear inclusion bodies in the proximal tubule; and fibrosis and the presence of infiltrates in the interstitial component. Treatment with EDTA slowed the progression of most alterations. No damage associated with the use of the chelating agent was observed. Longer term studies of the effects of this drug are required to establish whether the damage caused by lead poisoning may be reversed.

Animals↗
PubMed2002

Pauci-immune extracapillary glomerulonephritis and atheromatous embolization.

Renal atheroembolic disease presents several multisystemic signs and symptoms that may resemble the clinical signs of vasculitis. A few cases of renal atheroembolism associated with antineutrophil cytoplasmic antibodies (ANCA) have been described. We report the first case, to our knowledge, of a patient with cholesterol microemboli who also developed extracapillary glomerulonephritis in the presence of perinuclear ANCA (p-ANCA) with anti-myeloperoxidase ANCA. The patient had long-term follow-up of renal function after treatment with prednisone and cyclophosphamide.

Aged↗
PubMed2001

Alteration of the soluble guanylate cyclase system in the vascular wall of lead-induced hypertension in rats.

Low-level lead exposure is a known cause of hypertension that has been associated with increased reactive oxygen species activity and endothelial-dependent vasorelaxation impairment. The effect of lead exposure on the vascular nitric oxide (NO)/cyclic guanocine monophosphate (cGMP) system was analyzed. Wistar rats were exposed to 5 ppm lead acetate in the drinking water during 30 d. Mean arterial BP increased significantly in the lead-treated rats. Relaxation to both acetylcholine and sodium nitroprusside (SNP) was reduced in lead-treated rats; however, the vascular wall of lead-administered rats showed an increased expression of endothelial NO synthase. The expression of both subunits (alpha(1) and beta(1)) of soluble guanylate cyclase (sGC) and the cGMP accumulated in the vascular wall were decreased in lead-treated rats. Cotreatment of lead with vitamin C (3 mmol/L) prevented the increase on mean arterial BP, improved the relaxation to both acetylcholine and sodium nitroprusside, and restored the normal expression of endothelial NO synthase and sGC proteins in the vascular wall. In conclusion, lead exposure altered both the endothelium-dependent and -independent relaxing response and induced a reduced expression of sGC in the vascular wall. These effects were abrogated with the antioxidant vitamin C, which suggests the involvement of reactive oxygen species in the regulation of the NO/cGMP relaxing system in the vascular wall of lead-treated rats.

Acetylcholine↗
PubMed2000

Renal transplantation from non-heart beating donors: a promising alternative to enlarge the donor pool.

The aim of this study was to compare the survival and midterm function of kidneys from non-heart beating donors (NHBD) with those of kidneys from heart beating donors (HBD). From 1989 to 1998, 144 kidneys were procured from NHBD at the Hospital Clínico San Carlos in Madrid, of which 95 were transplanted. The kidney grafts were maintained from the moment of the diagnosis of cardiac arrest until the time of procurement by cardiopulmonary bypass. There was no significant difference in renal function and the number of rejection episodes between the NHBD and HBD transplants. The NHBD kidneys showed a 5.73-fold increase in the incidence of delayed graft function (adjusted relative risk 95% confidence interval, 2.82 to 11.62). One- and five-year survival rates for NHBD grafts were 84.6 and 82.7%, respectively, compared with 87.5 and 83.9% for HBD (P = 0.5767). Cox analysis showed that the predictive factors for worse NHBD graft survival were type of NHBD donor and the occurrence of corticoresistant rejection. Ninety of the NHBD organs were procured from subjects suffering irreversible cardiac arrest on the street who were transferred to our center for the sole purpose of donation. Fifty-four of these kidneys were transplanted and all showed primary function. When a strict protocol is adhered to, the outcome of renal transplant from NHBD compares well with that from HBD. It is believed that the high number of organs obtained from subjects undergoing irreversible cardiac arrest on the street might encourage the adoption of new criteria for the management of this type of pathology with the ultimate goal of kidney donation.

Adult↗
PubMedDate not supplied

Non-heart-beating donors: experience from the Hospital Clinico of Madrid.

Non-heart-beating donors (NHBD) have received attention in the last few years as an alternative source to increase the pool of kidney donors. The majority of reports focus on NHBD from controlled donors, i.e. patients who die in hospital. This report focuses on our experience using uncontrolled NHBD, i.e. patients who die outside of hospital and are transported to hospital for organ donation. We evaluated 188 renal transplantations performed in two periods 1989-1992 and 1995-2000. As to the latter period, renal transplantations from NHBD were compared to those from 345 heart-beating donor (HBD). Graft survival at 7 years shows a better tendency in NHBD group, with no statistical significance. When patients over 60 years of age were excluded from the group of patients receiving HBD kidneys, results were the same. At 2 years renal function post-transplantation was better in NHBD organs, as evaluated by serum creatinine and creatinine clearance, while after 2 years it was similar. The incidence of acute renal rejection was lower in NHBD; however, delayed graft function, as expected, was more prevalent in NHBD, although interestingly it did not influence long-term survival. In conclusion NHBD from deaths outside the hospital may be a good source of donor kidneys and also a way to successfully increase the pool for organ transplantation.

Adult↗