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R Saez

Publications and source records attributed to R Saez.

At least 19 recordsLinked to original sources
PubMed2001

Prenatal diagnosis of 13q- syndrome in a fetus with holoprosencephaly and thumb agenesis.

Partial deletion of the long arm of one of the chromosomes 13 is an exceedingly rare condition. We report such a case in a 32-week fetus presenting with polyhydramnios, growth restriction and multiple structural defects including alobar holoprosencephaly, facial abnormalities, clubfoot, clinodactyly and thumb agenesis. Fetal blood sampling revealed a 46,XY, del(13)(q22 --> qter) abnormal male karyotype. Postmortem examination confirmed the prenatal findings and showed other manifestations of the syndrome. To our knowledge, this case represents the first in which the prenatal ultrasound detection of holoprosencephaly in association with distal limb abnormalities led to the prenatal diagnosis of the 13q- syndrome.

Adult↗
PubMed1999

Isoform-specific insertion near the Grb2-binding domain modulates the intrinsic guanine nucleotide exchange activity of hSos1.

Two human hSos1 isoforms (Isf I and Isf II; Rojas et al., Oncogene 12, 2291-2300, 1996) defined by the presence of a distinct 15 amino acid stretch in one of them, were compared biologically and biochemically using representative NIH3T3 transfectants overexpressing either one. We showed that hSos1-Isf II is significantly more effective than hSos1-Isf I to induce proliferation or malignant transformation of rodent fibroblasts when transfected alone or in conjunction with normal H-Ras (Gly12). The hSos1-Isf II-Ras cotransfectants consistently exhibited higher saturation density, lower cell-doubling times, increased focus-forming activity and higher ability to grow on semisolid medium and at low serum concentration than their hSos1-Isf I-Ras counterparts. Furthermore, the ratio of GTP/GDP bound to cellular p21ras was consistently higher in the hSos1-Isf II-transfected clones, both under basal and stimulated conditions. However, no significant differences were detected in vivo between Isf I- and Isf II-transfected clones regarding the amount, stability and subcellular localization of Sos1-Grb2 complex, or the level of hSos1 phosphorylation upon cellular stimulation. Interestingly, direct Ras guanine nucleotide exchange activity assays in cellular lysates showed that Isf II transfectants consistently exhibited about threefold higher activity than Isf I transfectants under basal, unstimulated conditions. Microinjection into Xenopus oocytes of purified peptides corresponding to the C-terminal region of both isoforms (encompassing the 15 amino acid insertion area and the first Grb2-binding motif) showed that only the Isf II peptide, but not its corresponding Isf I peptide, was able to induce measurable rates of meiotic maturation, and synergyzed with insulin, but not progesterone, in induction of GVBD. Our results suggest that the increased biological potency displayed by hSos1-Isf II is due to higher intrinsic guanine nucleotide exchange activity conferred upon this isoform by the 15 a.a. insertion located in proximity to its Grb2 binding region.

3T3 Cells↗
PubMed1999

Local and systemic liberation of proinflammatory cytokines in ulcerative colitis.

Determination of plasma and tissue cytokine levels in inflammatory bowel disease have frequently resulted in conflicting data. In the present study we determined in patients with ulcerative colitis (UC), the levels of the proinflammatory cytokines interleukin (IL)-1beta, IL-6, interferon (IFN)-gamma, and tumor-necrosis factor (TNF)-alpha liberated by peripheral blood mononuclear cells (PBMC) and lamina propria mononuclear cells (LPMC) after 48-hr culture with pokeweed mitogen (PWM). IL-1beta, IL-6, IFN-gamma and TNF-alpha in the supernatant were detected by ELISA. Results show low basal levels of IL-1beta secretion by PBMC and LPMC, and a considerable increase after mitogen stimulation. Basal IL-6 production by PBMC was higher in UC patients than in controls [2029 pg/ml, CI95(-165 to 4223) vs 572 pg/ml (-383 to 1527) respectively, P = 0.05] and also after PWM activation [14,995 pg/ml (7759-22,230) vs 6598 pg/ml (3240-9956), respectively, P = 0.05]. In LPMC, no differences in IL-6 secretion were observed. TNF-alpha in activated PBMC of patients with UC was not significantly increased in relation to control (P = 0.09). No constitutive secretion of IFN-gamma was observed in mononuclear cells. IFN-gamma levels secreted by activated LPMC were lower in patients with UC than in controls [1571 pg/ml (-108 to 3251) vs 7953 pg/ml (3851-12,055), respectively, P = 0.03]. These results suggest that IL-6, IL-1beta, and TNF-alpha participate as mediators in the inflammatory phenomena observed in UC. Further studies are necessary to evaluate the role of IFN-gamma in this condition.

Adult↗
PubMed1999

Prenatal exposure to aluminum reduces expression of neuronal nitric oxide synthase and of soluble guanylate cyclase and impairs glutamatergic neurotransmission in rat cerebellum.

Exposure to aluminum (Al) produces neurotoxic effects in humans. However, the molecular mechanism of Al neurotoxicity remains unknown. Al interferes with glutamatergic neurotransmission and impairs the neuronal glutamate-nitric oxide-cyclic GMP (cGMP) pathway, especially in rats prenatally exposed to Al. The aim of this work was to assess whether Al interferes with processes associated with activation of NMDA receptors and to study the molecular basis for the Al-induced impairment of the glutamate-nitric oxide-cGMP pathway. We used primary cultures of cerebellar neurons prepared from control rats or from rats prenatally exposed to Al. Prenatal exposure to Al prevented glutamate-induced proteolysis of the microtubule-associated protein-2, disaggregation of microtubules, and neuronal death, indicating an impairment of NMDA receptor-associated signal transduction pathways. Prenatal exposure to Al reduced significantly the content of nitric oxide synthase and guanylate cyclase and increased the content of calmodulin both in cultured neurons and in the whole cerebellum. This effect was selective for proteins of the glutamate-nitric oxide-cGMP pathway as the content of mitogen-activated protein kinase and the synthesis of most proteins were not affected by prenatal exposure to Al. The alterations in the expression of proteins of the glutamate-nitric oxide-cGMP pathway could be responsible for some of the neurotoxic effects of Al.

Aluminum↗
PubMed1999

Differential roles of Akt, Rac, and Ral in R-Ras-mediated cellular transformation, adhesion, and survival.

Multiple biological functions have been ascribed to the Ras-related G protein R-Ras. These include the ability to transform NIH 3T3 fibroblasts, the promotion of cell adhesion, and the regulation of apoptotic responses in hematopoietic cells. To investigate the signaling mechanisms responsible for these biological phenotypes, we compared three R-Ras effector loop mutants (S61, G63, and C66) for their relative biological and biochemical properties. While the S61 mutant retained the ability to cause transformation, both the G63 and the C66 mutants were defective in this biological activity. On the other hand, while both the S61 and the C66 mutants failed to promote cell adhesion and survival in 32D cells, the G63 mutant retained the ability to induce these biological activities. Thus, the ability of R-Ras to transform cells could be dissociated from its propensity to promote cell adhesion and survival. Although the transformation-competent S61 mutant bound preferentially to c-Raf, it only weakly stimulated the mitogen-activated protein kinase (MAPK) activity, and a dominant negative mutant of MEK did not significantly perturb R-Ras oncogenicity. Instead, a dominant negative mutant of phosphatidylinositol 3-kinase (PI3-K) drastically inhibited the oncogenic potential of R-Ras. Interestingly, the ability of the G63 mutant to induce cell adhesion and survival was closely associated with the PI3-K-dependent signaling cascades. To further delineate R-Ras downstream signaling events, we observed that while a dominant negative mutant of Akt/protein kinase inhibited the ability of R-Ras to promote cell survival, both dominant negative mutants of Rac and Ral suppressed cell adhesion stimulated by R-Ras. Thus, the biological actions of R-Ras are mediated by multiple effectors, with PI3-K-dependent signaling cascades being critical to its functions.

3T3 Cells↗
PubMed1997

Cooperative transformation of NIH3T3 cells by G alpha12 and Rac1.

The heterotrimeric G-protein, G alpha12, together with the closely-related G alpha13, are members of the G12 class of alpha-subunits important in mediating the signaling from seven transmembrane domain-spanning receptors. Recent evidence implicating both G alpha12 and G alpha13 in the activation of signaling pathways involving members of the RHO gene family led us to examine the role of Rac1, RhoA and Cdc42Hs in the transforming properties of G alpha12. Asparagine 17 (Asn 17) dominant inhibitory mutants of Rac1, and to a lesser extent RhoA, block focus forming ability of the GTPase-deficient mutant of G alpha12 (G alpha12 Leu 229) in NIH3T3 cells. In turn, wild-type G alpha12 cooperates well with Rac1 Val 12 but not with RhoA Leu 63 mutant in transforming NIH3T3 cells. Interestingly, the morphology of foci induced by G alpha12 and RhoA mutants are strikingly similar and is distinct from those displayed by Rac1 Val 12 mutant. The fact that G alpha12's ability to induce mitogenesis in NIH3T3 cells is not significantly perturbed by C3 ribosyltransferase suggested that RhoA does not play a major role in G alpha12-induced mitogenic events. Activated mutant of Rac1 has previously been demonstrated to stimulate the activity of the stress-induced c-Jun N-terminal kinase/stress-activated protein kinases (JNK/SAPKs). Transient co-transfection of Rac1 Val 12 mutant with the wild-type G alpha12 in COS7 cells leads to the further activation of an exogenously expressed hemagglutinin(HA)-tagged JNK. Furthermore, the cooperation between G alpha12 and Rac1 in cellular transformation is correlated with their ability to stimulate transcription from c-fos serum response element (SRE).

3T3 Cells↗
PubMed1997

High-dose chemotherapy and autologous peripheral blood stem cell transplantation in patients with multiple myeloma and renal insufficiency.

Six patients with multiple myeloma and chronic renal insufficiency (serum creatinine >3.0 mg/dl), including four on dialysis, received high-dose busulfan and cyclophosphamide (BUCY) followed by autologous peripheral stem cell transplantation. Peripheral blood stem cells were collected after priming with cyclophosphamide, etoposide and G-CSF. Patterns of engraftment and toxicities were not apparently different from those seen in myeloma patients with normal renal function. There was one toxicity-related death, resulting from a massive spontaneous subdural hematoma. One patient died of disease progression 6 months after transplant, while the remaining four patients are alive and free of myeloma progression 6 to 39 months after high-dose therapy. Two of these patients have remained in complete remission for 28 and 39 months. Our experience suggests that high-dose therapy with BUCY and autologous peripheral blood stem cell rescue is feasible in patients with multiple myeloma and renal failure.

Adult↗
PubMed1997

Allogeneic bone marrow transplantation in patients who relapse after autologous transplantation.

Increasing numbers of patients have received autologous stem cell transplants (ASCT) for hematologic malignancies. Since only a fraction of these patients are cured, physicians are more frequently faced with the dilemma of how to manage relapse post-transplant. Potential advantages of allogeneic transplantation (alloBMT) over ASCT include lack of graft tumor contamination and presence of a graft-versus-tumor effect. For this reason, patients who relapse after ASCT are often considered candidates for allogeneic bone marrow transplantation. However, there is limited knowledge on the outcome of alloBMT in patients who relapse after ASCT. We retrospectively analyzed the outcome of 20 patients with malignant lymphoma (n = 14) and AML (n = 6) who underwent alloBMT after failing an ASCT. The median age was 30 (17-41) years and the interval from ASCT to alloBMT was 10.5 (2-25) months. Seventeen patients died between 0.3 to 11 months (median 2.0) after alloBMT, all due to BMT-related toxicities. Three patients remain alive and free of disease at 1.1, 1.2 and 2.5 years after alloBMT. Sixteen of the 18 evaluable patients (89%) developed grade II-IV acute GVHD. Patients undergoing alloBMT after ASCT have a very high treatment-related mortality and incidence of grade II-IV acute GVHD. Alternative treatments with salvage chemotherapy, radiation or investigational approaches should be considered in patients who relapse after ASCT.

Adolescent↗
PubMed1997

High-dose chemotherapy with autologous hematopoietic stem-cell support for breast cancer in North America.

PURPOSE: To identify trends in high-dose therapy with autologous hematopoietic stem-cell support (autotransplants) for breast cancer (1989 to 1995). PATIENTS AND METHODS: Analysis of patients who received autotransplants and were reported to the Autologous Blood and Marrow Transplant Registry. Between January 1, 1989 and June 30, 1995, 19,291 autotransplants were reviewed; 5,886 were for breast cancer. Main outcomes were progression-free survival (PFS) and survival. RESULTS: Between 1989 and 1995, autotransplants for breast cancer increased sixfold. After 1992, breast cancer was the most common indication for autotransplant. Significant trends included increasing use for locally advanced rather than metastatic disease (P < .00001) and use of blood-derived rather than marrow-derived stem cells (P < .00001). One-hundred-day mortality decreased from 22% to 5% (P < .0001). Three-year PFS probabilities were 65% (95% confidence intervals [Cls], 59 to 71) for stage 2 disease, and 60% (95% Cl, 53 to 67) for stage 3 disease. In metastatic breast cancer, 3-year probabilities of PFS were 7% (95% Cl, 4 to 10) for women with no response to conventional dose chemotherapy; 13% (95% Cl, 9 to 17) for those with partial response; and 32% (95% Cl, 27 to 37) for those with complete response. Eleven percent of women with stage 2/3 disease and less than 1% of those with stage 4 disease participated in national cooperative group randomized trials. CONCLUSION: Autotransplants increasingly are used to treat breast cancer. One-hundred-day mortality has decreased substantially. Three-year survival is better in women with earlier stage disease and in those who respond to pretransplant chemotherapy.

Adult↗
PubMed1996

Synergism between two growth regulatory pathways: cooperative transformation of NIH3T3 cells by G alpha 12 and c-raf-1.

The alpha-subunit of the heterotrimeric G-protein, G12, has been shown to induce cellular transformation when overexpressed or oncogenically activated in rodent fibroblasts. To investigate the interaction between Galpha12 transforming pathway and the Ras-Raf-MAPK pathway, we examined the ability of mitogenic signaling molecules in cooperating with Galpha12 in transforming NIH3T3 fibroblasts. We observed a striking cooperative effect on focus-forming ability when Galpha12 and c-raf-1 cDNAs were co-transfected into NIH3T3 cells. NIH3T3 cells coexpressing both Galpha12 and c-raf-1 resulted in the constitutive activation of the mitogenic-activated protein kinase (MAPK). In addition, the levels of GTP-bound Ras were elevated in Galpha12 transformed NIH3T3 cells. Our results provide a model for studying the effects of simultaneous activation of two distinct growth regulatory pathways in cellular transformation.

3T3 Cells↗
PubMed1996

Physical and psychosocial functioning of 117 survivors of bone marrow transplantation.

All surviving patients receiving a BMT at our center since 1976 were surveyed. Among 163 eligible patients, 145 were contacted and 117 (81%) responded. Their median follow-up was 55 months (range 6-154). The research instruments consisted of a demographic questionnaire, a current medical status form, a quality of life questionnaire (Nottingham Health Profile), and a screening instrument for psychiatric morbidity (the 28-item version of the General Health Questionnaire). Current functioning varied considerably across patients. They reported a high use of medical services (37%) and varied ongoing medical problems within the last 6 months. Most of them (93%) received Karnofsky ratings of 80 or above. Eight percent had current chronic GVHD. Comparing our patients' quality of life with a British reference population, most important differences were found for physical mobility, work, and sex life. Psychiatric morbidity in BMT survivors was higher than in a Spanish general population. Multivariate analyses revealed that a higher systemic symptomatology score, a lower educational level, an older age at BMT, a shorter time post-BMT, a female gender, and impotence were significant predictors of an impaired overall quality of life. Similarly, a higher systemic symptomatology score, a shorter time post-BMT, a higher number of major infections, and a lower educational level were predictive factors of a higher psychosocial distress. No differences in quality of life or psychosocial status between allogeneic and autologous transplants were found. Quality of life and psychosocial distress improved with the passage of time, specially within the first 3 years.

Adolescent↗
PubMed1995

A novel insertional mutation in the TC21 gene activates its transforming activity in a human leiomyosarcoma cell line.

TC21 is the fourth member of the ras gene family to exhibit oncogenic activation in human tumor cells. To assess the prevalence of activated TC21 oncogenes in human tumors, we have developed sensitive single-strand conformational polymorphism (SSCP) conditions and immunological reagents for the detection of both single base alterations and/or overt overexpression in a wide spectrum of human tumor cell lines and surgical samples. In an initial examination of 33 human tumor specimens, we observed a novel nine basepair three amino acids insertion at TC21 codon 24 in one human uterine leiomyosarcoma cell line, SK-UT-1. This mutant allele when transfected into NIH3T3 cells, displayed high transforming activity comparable to that of the Leu72 oncogenic mutant identified by expression cDNA cloning from a human ovarian carcinoma cell line. Comparing the level of GTP-binding by the mutant and normal TC21 products revealed that this novel lesion increases the GTP-bound form of the TC21 molecule. These findings imply that the mechanism by which mutations activate the oncogenic properties of this ras-related molecule is analogous to that of previously known ras family members.

3T3 Cells↗
PubMed1994

Sequential administration of recombinant human interleukin-3 and granulocyte-macrophage colony-stimulating factor after autologous bone marrow transplantation for malignant lymphoma: a phase I/II multicenter study.

Preclinical studies of recombinant human interleukin-3 (rhIL-3) and granulocyte-macrophage colony-stimulating factor (rhGM-CSF) have shown enhancement of multilineage hematopoiesis when administered sequentially. This study was designed to evaluate the safety, tolerability, and biologic effects of sequential administration of rhIL-3 and rhGM-CSF after marrow ablative cytotoxic therapy and autologous bone marrow transplantation (ABMT) for patients with malignant lymphoma. Thirty-seven patients (20 patients with non-Hodgkin's lymphoma and 17 patients with Hodgkin's disease) received one of four different treatment regimens before ABMT. Patients were entered in one of four study groups to receive rhIL-3 (2.5 or 5.0 micrograms/kg/day) administered by subcutaneous injection for either 5 or 10 days starting 4 hours after the marrow infusion. Twenty-four hours after the last dose of rhIL-3, rhGM-CSF (250 micrograms/m2/d as a 2-hour intravenous infusion) administration was initiated. rhGM-CSF was administered daily until the absolute neutrophil count (ANC) was > or = 1,500/microL for 3 consecutive days or until day 27 posttransplant. The most frequent adverse events in the trial included nausea, fever, diarrhea, mucositis, vomiting, rash, edema, chills, abdominal pain, and tachycardia. Three patients were removed from the study because of chest, skeletal, and abdominal pain felt to be probably related to study drug. Four patients died during the study period because of complications unrelated to either rhIL-3 or rhGM-CSF. The median time to recovery of neutrophils (ANC > or = 500/microL) and platelets (platelet count > or = 20,000/microL) was 14 and 15 days, respectively. There were fewer days of platelet transfusions than seen in historical control groups using rhGM-CSF, rhG-CSF, or rhIL-3 alone. In addition, there were fewer days of red blood cell transfusions compared with historical controls using no cytokines or rhGM-CSF. These data indicate that the sequential administration of rhIL-3 and rhGM-CSF after ABMT is safe and generally well-tolerated and results in rapid recovery of multilineage hematopoiesis.

Adult↗
PubMed1994

Nuclear calmodulin/62 kDa calmodulin-binding protein complexes in interphasic and mitotic cells.

We report here that a 62 kDa calmodulin-binding protein (p62), recently identified in the nucleus of rat hepatocytes, neurons and glial cells, consists of four polypeptides showing pI values between 5.9 and 6.1. By using a DNA-binding overlay assay we found that the two most basic of the p62 polypeptides bind both single- and double-stranded DNA. The intranuclear distribution of calmodulin and p62 was analysed in hepatocytes and astrocyte precursor cells, and in proliferating and differentiated astrocytes in primary cultures by immunogold-labeling methods. In non-dividing cells nuclear calmodulin was mostly localized in heterochromatin although it was also present in euchromatin and nucleoli. A similar pattern was observed for p62, with the difference that it was not located in nucleoli. p62/calmodulin complexes, mainly located over heterochromatin domains were also observed in interphasic cells. These complexes remained associated with the nuclear matrix after in situ sequential extraction with nucleases and high-salt containing buffers. In dividing cells, both calmodulin and p62 were found distributed over all the mitotic chromosomes but the p62/calmodulin aggregates were disrupted. These results suggest a role for calmodulin and p62 in the condensation of the chromatin.

Animals↗
PubMed1994

Oncogenic activation of human R-ras by point mutations analogous to those of prototype H-ras oncogenes.

R-ras, K-rev-1/rap and TC21, are more closely related to prototype H-ras than any other known members of the ras superfamily. We recently isolated a mutationally activated TC21 oncogene from a human ovarian carcinoma cell line. Based upon these observations, we sought to re-examine the transforming potential of R-ras, which was reported earlier to lack transforming capacity. Mutations were introduced into the R-ras gene at codons 38 or 87, analogous to positions 12 and 61, respectively, responsible for H-ras oncogene activation. While both mutations resulted in acquisition of R-ras transforming capacity for NIH3T3 cells the position 61 was shown to be more active. Transfectants expressing either R-ras mutant formed colonies in soft agar and were tumorigenic in vivo. As has been reported for H-ras, R-ras cooperated with c-raf-1 in inducing transformation of NIH3T3 cells. These results imply interactions in R-ras and c-raf-1 signaling pathways. We observed R-ras transcripts of 4.6 and 1.2 kb ubiquitously expressed in each of a variety of tissues examined. All these findings raise the possibility that R-ras, like prototype ras genes, may be mutationally activated as an oncogene in some human malignancies.

3T3 Cells↗
PubMed1993

Derangement of astrogliogenesis as a possible mechanism involved in alcohol-induced alterations of central nervous system development.

We have postulated that the brain alterations observed after "in utero" alcohol exposure could be due, in part, to a direct effect of ethanol on astrogliogenesis. In the present work we summarize the main findings concerning the effect of prenatal exposure to alcohol on astrocytes in primary culture. We have found that this treatment alters astrocyte growth and the content and synthesis of DNA and proteins. However, "in utero" exposure to ethanol also causes important alterations in the astrocyte cytoskeleton which could be related to an alteration in the amount and activity of several plasma membrane glycoproteins. These results agree with ones obtained "in vivo" and suggest that ethanol-induced alterations in astrogliogenesis could be an important mechanism underlying the CNS disfunctions observed after prenatal exposure to ethanol.

Animals↗
PubMed1992

Prenatal exposure to ethanol alters plasma membrane glycoproteins of astrocytes during development in primary culture as revealed by concanavalin A binding and 5'-nucleotidase activity.

We have investigated the effect of prenatal exposure to ethanol on the extent of binding and surface distribution of the lectin concanavalin A (con A) on rat cortical astrocytes during the periods of proliferation and differentiation in primary culture. The enzymatic activity of the plasma membrane glycoprotein 5'-nucleotidase was also assessed. The cells were obtained from control fetuses (no exposure to ethanol) and from fetuses prenatally exposed to ethanol. The main findings were: 1) both proliferating and differentiating control astrocytes showed two distinct types of surface con A receptors that could correspond to high- and low-affinity binding sites; 2) the extent of con A binding was greater in mature than in proliferating control cells; 3) the distribution of con A on cell surface components changed with differentiation; 4) the activity of 5'-nucleotidase showed a substantial increment during the period of differentiation; and 5) prenatal exposure to ethanol clearly decreased the ability of astrocytes to bind con A, altered the surface distribution of the receptors for this lectin, and decreased the activity of 5'-nucleotidase. These effects were more marked in proliferating cells. In conclusion, it is shown that the extent of con A labeling and the activity of 5'-nucleotidase in astrocytes are dependent on the stage of cell differentiation and that prenatal exposure to ethanol alters the plasma membrane structure of these cells during development.

5'-Nucleotidase↗