Search PubMed⌕ Search

Biomedical subjects

L Riera

Publications and source records attributed to L Riera.

At least 19 recordsLinked to original sources
PubMed1999

Comparative study of carbohydrate antigen 195 and carcinoembryonic antigen for the diagnosis of pancreatic carcinoma.

The expression CA195 in serum, defined by monoclonal antibody CC3C195 (IgM), was studied in 67 patients with pancreatic cancer and in 138 patients with biliary or pancreatic benign disease. The results were compared with carcinoembryonic antigen (CEA) expression. The overall sensitivity of the CA195 assay (> 12 U/ml) was higher than that for CEA (89.5% vs. 53.7%) (p < 0.001). Sensitivity was increased to 92.5% with the simultaneous use of the two antigens, but the difference was statistically significant only with CEA (p < 0.001). The specificity of CA195 calculated from all patients with benign diseases was lower than that of CEA (73.1% vs. 89.8%). However, using a cutoff value of 100 U/ml for CA195, the specificity of this antigen (82%) was higher than that of CEA. These results demonstrate that marked elevations of tumor antigen CA195 are relatively specific for pancreatic carcinoma, and that this antigen is superior to CEA for diagnosing pancreatic cancer by virtue of its higher sensitivity.

Antibodies, Monoclonal↗
PubMed1999

In vitro and in vivo expression analysis of the interferon-inducible 203 gene.

The interferon (IFN)-inducible protein family 200 is encoded by structurally related genes located on mouse chromosome 1. The encoded proteins so far characterized and designated p202, p204, and pD3 contain at least one copy of a conserved 200 amino acid domain in addition to other regions that are different or missing among the various family members. We have recently characterized a cDNA clone (203 cDNA) encoding a 408 amino acid protein bearing structural similarities to p202 and p204. Here, we report its pattern of expression in vitro and in vivo. In vitro, the mRNA and protein encoded by the 203 gene were increased by IFN-alpha in several cell lines of different histologic origin. By contrast, no significant induction was observed in vivo in mice from C57BL/6 and BALB/c strains even after treatment with the IFN-inducer poly rI:rC. In addition, the constitutive expression of 203 gene was restricted to some myeloid and lymphoid tissues, namely, thymus, bone marrow, and spleen. Comparison of the expression pattern of the 203 and 202 genes in three mouse strains revealed that they exhibit a differential inducibility by IFN and a reciprocal expression pattern. The 203 mRNA was constitutively expressed in C57BL/6 and BALB/c mice and undetectable in the spleen of DBA/2 mice. The 202 mRNA was strongly induced by poly rI:rC in the spleen of DBA/2 and BALB/c mice but absent in C57BL/6 mice. Southern analysis revealed a restriction fragment length polymorphism in the 203 locus. Taken as a whole, these results demonstrate a remarkable difference in the in vivo IFN responsiveness of two members belonging to the same gene family with a similar degree of IFN inducibility in vitro. Moreover, the reciprocal expression pattern in C57BL/6 and DBA/2 mice could mean that p203 and p202 play the same role in a mouse strain in which only one of them is expressed.

3T3 Cells↗
PubMed1999

Donor age and delayed graft function as predictors of renal allograft survival in rejection-free patients.

BACKGROUND: Transplant recipients of kidneys harvested from old donors have a high incidence of delayed graft function (DGF) and a poor graft outcome. This result is partly explained by the increased incidence of acute rejection in patients suffering from DGF. However, the long-term impact of donor age and DGF in rejection free renal transplants is not well established. The aim of the present work is to evaluate the impact of donor age and DGF on long-term outcome in renal transplants with or without acute rejection. PATIENTS: We review all cadaveric kidney transplants performed in our centre between April 1984 and December 1995 treated with a cyclosporin-based immunosuppression. RESULTS: Five hundred and ninety-five patients were included. The overall incidence of DGF was 29.1%, and this event was associated with an increased donor age and cold ischaemia time. Univariate and multivariate analysis showed that graft loss was associated with acute rejection (relative risk (RR) 2.24, 95% confidence interval (CI) 1.62-3.01); DGF (RR 1.83, 95% CI 1.32-2.54); donors >50 years (RR 1.65, 95% CI 1.13-2.38); and retransplantation (RR 1.52, 95% CI 1.01-2.31). In rejection-free patients there were two independent predictors of graft failure: donor >50 years (RR 2.40, 95% CI 1.45-4.01); and DGF (RR 2.42, 95% CI 1.53-3.84). CONCLUSIONS: Regardless of the presence of acute rejection, delayed graft function amplifies the detrimental effect of advanced donor age on long-term graft outcome.

Adult↗
PubMed1999

Human cytomegalovirus stimulates cellular dihydrofolate reductase activity in quiescent cells.

Human cytomegalovirus (HCMV) productively infects quiescent fibroblasts in which the levels of deoxynucleotide triphosphates (dNTPs) and cell functions involved in DNA metabolism are very low. Since sufficient dNTPs levels are essential for human HCMV replication, host cell enzymes involved in the biosynthesis of dNTPs might be expected to be stimulated by viral infection in quiescent cells. We report that HCMV infection of quiescent fibroblasts stimulates the activity of cellular dihydrofolate reductase (DHFR), a key enzyme in DNA precursor synthesis. We also demonstrate that suppression of DHFR activity by the specific inhibitor methotrexate prevents HCMV replication and DNA synthesis. These observations indicate that induction of DHFR activity by HCMV is required for efficient viral replication in quiescent fibroblasts.

Cells, Cultured↗
PubMed1998

A good alternative to reduce the kidney shortage: kidneys from nonheartbeating donors.

BACKGROUND: Because of the shortage of kidneys available for transplantation, we began in 1985 to harvest kidneys from non-heartbeating (NHB) donors. METHODS: We compared the results of a group of 66 kidney recipients from NHB donors (NHB group) with 122 kidney recipients from heartbeating donors (HB group). We analyzed, in the NHB group, the influence of ischemia times in graft survival and we tested the best cut-offs by receiver operating characteristic curves. We also studied, using a univariate and multivariate Cox hazard model, the capacity of different variables to predict graft loss. RESULTS: Patient and graft survival were similar in both groups during the follow-up. The percentage of delayed graft function was the only significant difference between both groups (NHB group 62% vs. HB group 32%; P=0.0001). Delayed graft function, in the NHB group, is influenced by the warm ischemia time, which is directly related to the number of days to achieve a serum creatinine<300 mmol/L (P=0.0001). The best cut-off times in this group were 45 min for warm ischemia time and 22 hr for cold ischemia time. Recipients have a greater likelihood of losing the graft beyond those limits (P=0.017, relative risk: 7.3). The incidence of acute rejection was similar in both groups, and it was the only predictor factor of graft loss in the complete series of patients (P=0.0001), in the NHB group (P=0.007), and in the HB group (P=0.02). CONCLUSIONS: Reducing the incidence of acute rejection and shortening ischemia time are conditions needed to guarantee a long graft survival of kidneys from NHB donors.

Adult↗
PubMed1998

Primary immunosuppression with mycophenolate mofetil and antithymocyte globulin for kidney transplant recipients of a suboptimal graft.

BACKGROUND: In renal transplantation the beneficial immunosuppressive effects of cyclosporin (CsA) may be curtailed by its nephrotoxicity, specially in patients receiving a cadaveric allograft from suboptimal donors or at risk of delayed graft function. Mycophenolate mofetil (MMF) and antithymocyte globulin (ATG) have each demonstrated to be potent immunosuppressants in renal transplantation. In a prospective analysis we have studied the results at 6 months of the combination of MMF, ATG and low-dose steroids in patients with low immunological risk receiving a first cadaveric renal allograft from a suboptimal donor or at risk of delayed graft function. METHODS: Patients with preformed reactive antibodies < 500% receiving a first graft from a suboptimal donor (age > or = 40 years, non-heart-beating, acute renal failure, arterial hypertension) or at risk of delayed graft function (cold ischaemia time > or = 24 h) were eligible for this open single-arm pilot trial. From September 1996 to March 1997 we recruited 17 patients. They were treated with MMF 2 g p.o. preoperatively, and after transplantation at 3 g/day; rabbit ATG i.v. at 2 mg/kg preoperatively, and 1.5 mg/kg/day the first day after transplantation, followed by four doses of 1 mg/kg on alternate days; prednisone was given at 0.25 mg/kg/day and reduced progressively to 0.1 mg/kg/day at 3 months. Primary outcomes were incidence of biopsy-proven acute rejection, delayed graft function, opportunistic infections, graft and patient survival, and the need for introduction of CsA treatment. RESULTS: delayed graft function occurred in two cases (12%). Four of 17 patients (24%) had a biopsy-proven acute rejection (2 grade I and 2 grade II) within the first 3 months after transplantation. CsA was added in two cases with grade II biopsy-proven acute rejection, and in one with grade I biopsy-proven acute rejection. In one patient MMF was replaced by CsA because of gastrointestinal intolerance. Mean serum creatinine 6 months after transplantation was 159+/-59 micromol/1. Cytomegalovirus tissue invasive disease occurred in one patient (6%). At 6 months follow-up all patients are alive with functioning allografts. CONCLUSIONS: These preliminary results suggest that in low-immunological-risk patients who receive a suboptimal renal allograft or at risk of delayed graft function, the combination of MMF, ATG, and steroids is an efficient immunosuppressive regime that may avoid the use of CsA in 70% of the recipients.

Adult↗
PubMed1997

Molecular cloning and expression of an interferon-inducible protein encoded by gene 203 from the gene 200 cluster.

We report here the complete coding sequence of a 203 cDNA, a member of the interferon-inducible Ifi 200 gene family. By combining reverse-transcriptase PCR and rapid amplification of cDNA ends (RACE) techniques we have obtained a 3.8-kb cDNA corresponding to a 203 mRNA. When used as a probe in northern analysis, its 3' segment hybridized to a 3.8-kb interferon-inducible mRNA, whereas the 5'-end additionally hybridized to a less abundant interferon-inducible 1.8-kb mRNA. Nucleotide sequence analysis revealed that the two mRNAs share the 5'-untranslated region and the same open reading frame, which encodes a hydrophilic protein composed of 408 amino acids. The difference between them is due to a 3'-untranslated region extended by alternative polyadenylation site selection. Furthermore, 203 mRNA was found to be inducible by interferon-alpha in various murine cell lines. Using polyclonal antibodies raised against a segment specific for the 203 protein, we established that p203 protein levels increase on treatment with interferon-alpha in murine fibroblasts and that p203 is located in the nucleus.

3T3 Cells↗
PubMed1997

Transfer of the interleukin-2 gene into human cancer cells induces specific antitumor recognition and restores the expression of CD3/T-cell receptor associated signal transduction molecules.

Normal peripheral blood mononuclear cells (PBMC) were co-cultured with a human lung cancer cell line (LC89) transduced with the interleukin-2 (IL-2), IL-7, granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor-alpha (TNF-alpha) genes to evaluate the capacity of the engineered cells to: allow survival of CD3+ and CD56+ cells, generate cytotoxic effectors with HLA class I restricted and unrestricted antitumor activity, and interfere in the molecular organization of the CD3/T-cell receptor associated signal transduction machinery. When PBMC were cultured up to 3 weeks with IL-2 releasing LC89 cells (LC89/IL-2), the number of viable CD3+ and CD56+ lymphocytes was much greater than in cultures with parental cells or with LC89 cells transduced with the other cytokine genes. After 1 week of coculture, a variable degree of restricted and unrestricted killing directed against different targets was observed. When the cultures were prolonged up to 3 weeks, LC89/IL-2 cells induced a marked increase in specific cytotoxic activity, which was coupled to a further enhancement of unrestricted lytic function. In the presence of LC89/IL-7 cells the degree of specific lysis remained unchanged, whereas unrestricted effectors were markedly decreased. No cytotoxic activity could be induced by LC89/GM-CSF and LC89/TNF-alpha cells in the few lymphocytes surviving after 3 weeks of culture. Coculture of parental LC89 cells with PBMC was consistently associated with a downmodulation in the expression of the CD3 zeta chain, as well as of the tyrosine kinases p56ick and ZAP-70. On the contrary, LC89/IL-2 cells, and not LC89 cells transduced with the IL-7, GM-CSF, or TNF-alpha gene, were capable of reverting the immunosuppressive effect exerted by the tumor cells. This protective effect could be maintained in cultures prolonged up to 4 weeks. When the same cultures were set up in Transwell, ie, with a membrane separation between cancer cells and PBMC, the expression of the CD3 zeta chain and of the p56ick and ZAP-70 tyrosine kinases remained unchanged under all culture conditions, indicating that the downmodulation of T-cell signal transduction molecules requires a direct cell to cell contact. These results show that transfer of the IL-2 gene into the DNA of human cancer cells promotes both restricted and unrestricted antitumor activity, and is capable of restoring and maintaining the expression of molecules involved in the process of T-cell mediated tumor cell recognition, thus underlining the potential role of the IL-2 gene in the design of vaccination protocols with cytokine gene transduced cancer cells.

Adenocarcinoma↗
PubMed1997

[Prevalence of hepatitis C antibodies in plasma donors for the treatment of Argentine hemorrhagic fever].

For Argentine Hemorrhagic Fever, a disease caused by Junin virus (JV), there is an effective treatment, consisting of the transfusion of immune plasma (IP). This plasma is obtained from individuals who have had the disease. Since Hepatitis C virus (HCV) is transmitted parenterally, this study was aimed to estimate the prevalence of anti-HCV in a population of IP donors. In this study, 376 donors (47 females and 329 males) were studied: 95 individuals (24 females and 71 males) who had had FHA but had not received treatment and 88 laboratory workers (57 females and 31 males) who were included as controls. Serum samples were tested by EIA (Abbott, Germany) for HCV, and later confirmed by LIATEK (Organon, Ireland). Antibodies to HCV were detected in 29/376 donors (7.7%), in only 1/95 (1.0%) untreated convalescents of AHF and in 1/ 88 (1.1%) of laboratory workers. Retrospective analysis of the seroconversion for HCV in these individuals demonstrated that in 16/24 donors (66.6%) the infection by HCV was probably associated with the IP transfusion. The data presented herein show how the infection with HCV was disseminated among donors of IP, stressing the risk associated to transfusional practices, and emphasizing the need of vaccination to prevent AHF and also the risk inherent to its treatment.

Adult↗
PubMed1996

Interleukin-8 induces the accumulation of B-cell chronic lymphocytic leukemia cells by prolonging survival in an autocrine fashion.

Several cytokines have been suggested to play a regulatory action on the neoplastic clone of patients with B-cell chronic lymphocytic leukemia (B-CLL) by interfering in the differentiation, proliferation, or death/survival pathways. Interleukin-8 (IL-8) is a chemoattractant protein constitutively expressed at the mRNA level and released by B-CLL cells. In view of the presence of the IL-8 receptor mRNA and of specific IL-8 binding, confirmed also by Scatchard analysis using 125I-IL-8, the study was extended to evaluate the possible regulatory role of this cytokine on B-CLL cells. IL-8 failed to show any in vitro proliferative effect on leukemic B-CLL cells. By contrast, the propidium iodide (PI) staining of the DNA content showed that IL-8 could prolong the survival of resting B-CLL cells in 11 of 16 cases studied. In the remaining 5 cases, 90.6% +/- 4.39% SD of the cells after culture remained viable and IL-8 could exert a significant death protection action after pretreatment with 10(-4) mol/L hydrocortisone, which reduced the percentage of viable B-CLL cells. The dose range of IL-8 capable of inducing the prolonging survival effect is comparable with the levels of IL-8 released constitutively by B-CLL cells, indicating that the death protection action is exerted at physiologic doses. The in vitro rescue from death induced by IL-8 is reflected by an increased expression of bcl-2 mRNA in B-CLL cases incubated in the presence of IL-8. These findings were further confirmed at the protein level, because in B-CLL cells that displayed a bimodal bcl-2 intracytoplasmatic protein expression IL-8 was capable of upmodulating the bcl-2high expression peak. The potential autocrine regulatory action exerted by IL-8 is supported by the evidence that exogenous IL-8 can upregulate IL-8 mRNA in B-CLL cells. These results, together with the demonstration that antibody-mediated neutralization of endogenous IL-8 could induce a significant in vitro reduction in the number of living cells, further support the hypothesis that, in B-CLL, the physiologic doses of IL-8 released constitutively by the leukemic clone may play an autocrine role in the process of cell accumulation characteristic of this disease.

Antigens, CD↗
PubMed1995

Renal angioscopy.

Explore the source record for details and available documents.

Accidents, Traffic↗
PubMed1994

Effect of different preservation solutions on adenine nucleotide content and metabolism in human kidney transplantation.

Differences in purine metabolism produced by three preservation solutions were studied by determining the adenine nucleotide (ATP, ADP, AMP, and IMP) and nucleoside (adenosine, inosine, and hypoxanthine) levels in human kidney cortical biopsies. Forty kidney allografts were studied using University of Wisconsin (UW) solution (n = 20), Euro-Collins (EC) solution (n = 12), and modified EC solution with mannitol (M; n = 8). No significant differences were found between the three solutions studied with regard to ATP, ADP, or AMP changes. The mean ATP level (nmol/mg prot +/- SEM) at the end of preservation in the UW group was 2.7 +/- 0.3 nmol/mg, in the EC group 3.8 +/- 0.7 nmol/mg, and in the M group 2.3 +/- 0.4 nmol/mg. ATP 30 min after reperfusion in the UW, EC, and M groups was 5.7 +/- 0.8 nmol/mg, 6.4 +/- 1.0 nmol/mg, and 4.6 +/- 0.5 nmol/mg, respectively. However, an important difference appeared in the catabolic products determined. Kidneys perfused with UW solution had a significantly higher level of adenosine (2.6 +/- 0.6 nmol/mg), inosine (11.8 +/- 2.2 nmol/mg), and hypoxanthine (18.1 +/- 2.1 nmol/mg) at the end of cold storage than those perfused with EC (0.4 +/- 0.1 nmol/mg, 2.0 +/- 0.8 nmol/mg, and 7.1 +/- 1.4 nmol/mg) and M solutions (0.2 +/- 0.05 nmol/mg, 0.5 +/- 0.1 nmol/mg, and 5.2 +/- 0.6 nmol/mg; P < 0.05). These levels returned to initial values 30 min postreperfusion and there were no differences with the EC or M solution groups at that time.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗
PubMed1994

Cytokine gene therapy in oncology.

Over the last few years the possibility of introducing foreign material into the genome of host cells has become technically feasible. This has opened a new era in the treatment of congenital disorders, but has also offered potential innovative avenues in the management of cancer patients. Here, we shall discuss how cytokine genes may be successfully transduced into the DNA of different experimental tumours and how through this approach the tumorigenicity of the neoplastic cells may be abrogated. Emphasis will be given on the demonstration that following cytokine gene transfer, namely with the interleukin 2 (IL-2) gene, two of the primary goals of an optimal immunotherapeutic approach, i.e. anti-tumour specificity and memory, may be achieved. Attention will be focused, in particular, on the results so far obtained, as well as on ongoing studies, with human tumour cells engineered to release different cytokine genes. The design and activation of the first clinical protocols aimed at treating advanced cancer patients with cytokine gene-transduced neoplastic cells will also be discussed, together with other strategies of genetic engineering currently under investigation.

Animals↗
PubMed1993

Relationship between donor renal interstitial surface and post-transplant function.

Forty-three biopsies were performed between 30 and 60 min after reperfusion. Patients (22 males/21 females, mean age 41 +/- 12 years, mean donor age 32 +/- 14 years) were treated either with antilymphocytic globulin, cyclosporin, and prednisolone (24 cases), or OKT3, cyclosporin, and prednisolone (19 cases). Ten patients had delayed post-transplant renal function (DPRF), defined as haemodialysis requirements after surgery, and seven patients had acute rejection 11 +/- 16 days post-transplant. Kidneys were perfused with a hypertonic solution containing mannitol. All patients were followed up for at least 30 months. During follow-up, five patients lost their grafts due chronic rejection, two patients due to noncompliance and one due to recurrence of focal segmental glomerulosclerosis. One patient died from heart infarction. Biopsies were stained with H&E, Masson's trichrome, periodic acid-Schiff (PAS) and silver methenamine. Interstitial fibrosis, interstitial oedema, tubular vacuolization, and peritubular capillary oedema were measured using a semiquantitative scale. Five 400 x magnification micrographs of cortical interstitium from silver-methenamine-stained sections were used to measure percentage of interstitial surface with a morphometer. Interstitial surface was 18.7 +/- 6.2% (range 3.2-35.3%). A positive correlation was found between interstitial surface and donor age (r = 0.469, P = 0.0015). No relationship was found between warm and cold ischaemia times and tubular vacuolization or peritubular capillary oedema.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Acquired cystic renal disease associated with renal carcinoma: report of 3 cases].

Presentation of three cases of haemodialysis patients with acquired cystic renal disease (ACRD) who, over the course of their illness, developed clear cells renal carcinoma. The paper emphasizes the common association of these two entities and the need to consider ACRD cases as patients at high risk of developing renal neoplasia.

Adenocarcinoma↗