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F Garrido

Publications and source records attributed to F Garrido.

At least 73 records · Page 4Linked to original sources
PubMed1997

Lack of correlation between codon 12 K-ras mutations and major histocompatibility complex antigens in bronchogenic carcinomas.

In experimental systems, an association between K-ras activity and expression of major histocompatibility complex (MHC) molecules has been reported. In this study, 52 surgically resected bronchogenic carcinomas were studied for human leukocyte antigen (HLA) class I and II expression, and for the presence of point mutations in codon 12 of the K-ras gene. HLA class I loss was detected in 18 carcinomas, and most of the tumors (43 cases) were found negative for HLA class II antigen expression by the APAAP technique with specific monoclonal antibodies. Analysis using the polymerase chain reaction (PCR), together with selective hybridization using mutation-specific synthetic oligonucleotides, demonstrated K-ras mutations in five cases, all of them corresponding to the adenocarcinoma subtype (31.2% of the adenocarcinomas included in our study) with a poor degree of differentiation. We did not find any correlation between K-ras mutations and HLA class I and II expression in bronchogenic carcinomas. Therefore, it would appear that downregulation of MHC antigens by point mutations of K-ras does not take place in vivo.

Carcinoma, Bronchogenic↗
PubMed1997

Protein bound polysaccharide PSK abrogates more efficiently experimental metastases derived from H-2 negative than from H-2 positive fibrosarcoma tumor clones.

We studied the effect of protein-bound polysaccharide PSK on metastatic colonization of BALB/c mice after intravenous injections of different syngeneic murine H-2 positive and H-2 negative tumor clones. The tumor lines used were different clones from chemically induced fibrosarcomas (GR9.B9, an H-2 negative clone from GR9 tumor, and B7.1.B4, an H-2 positive clone from B7.1 tumor). These clones were selected because of their different sensitivity to NK cytotoxicity, which was related to MHC class I expression. Pretreatment of mice with PSK inhibited metastatic colonization derived from B9 H-2 negative tumor cells. In contrast, lung colonization of PSK treated mice injected with B7.1.B4 H-2 positive tumor cells was higher, and differences in the number of colonies between untreated and PSK treated mice were small. In several experiments the effect of PSK was attenuated to a greater degree when high numbers of cells were injected. Abrogation of NK cells with anti-asialo GM1 serum significantly increased (in all tumors and at different cell doses) the number of metastatic colonies in comparison with untreated mice injected with tumors, regardless of the cell dose used. These results clearly suggest that NK cell activation in vivo by the protein bound polysaccharide PSK abrogates metastasis formation in mice. Abrogation was dependent on the H-2 phenotype even when pretreatment consisted of a single dose of PSK. This effect, related to the NK sensitivity of the tumor target, can be used to predict the effect of PSK in vivo.

Animals↗
PubMed1996

Methylated CpG points identified within MAGE-1 promoter are involved in gene repression.

The MAGE-1 gene, expressed in some tumors of different histological origins, codes for a tumor antigen recognized by cytotoxic T lymphocytes. The gene is not expressed in normal tissues with the exception of testes. The present study was designed to investigate the relationship between methylation of the MAGE-1 promoter and inactivation of the MAGE-1 gene. We examined the extent to which MAGE-1 B'B promoter sequences are methylated in tumor-cell lines, in order to determine whether methylation correlates with MAGE-1 expression. Using methylation-sensitive restriction analysis followed by polymerase chain reaction (PCR), we found an inverse correlation between methylation of the MAGE-1 B'B region and MAGE-1 expression. An unmethylated state was identified in DNA from sperm and some tumor-cell lines of different origins. In contrast, a hypermethylation state was found in leukocytes and other MAGE-1 non-expressing cells. Furthermore, treatment with 5-aza-2'-deoxycytidine, a demethylating agent, induced MAGE-1 expression in tumor-cell lines in which we found no direct relation between transcriptional activity of the B'B region and MAGE-1 expression. Binding of the nuclear factors to the B'-methylated probe was strongly inhibited, indicating that methylation of cytosine interferes directly in the binding of transcriptional factors.

Antigens, Neoplasm↗
PubMed1996

Bioprocessing with genetically modified and other organisms: case studies in processing constraints.

Whereas the gene stability related considerations are important in bioprocessing with recombinant cultures, bioreactor design and scale-up require attention to the often reduced shear tolerance of the genetically altered biocatalysts relative to the corresponding wild strains. In addition, the peculiarities of expression of the rDNA product impact the downstream recovery methods. As a consequence, a bioprocessing scheme and the process machinery designed for a naturally occurring organism may need significant modifications for use with a genetically modified variety of the same organism. The case studies described highlight some of the processing constraints and consideration of general relevance.

Animals↗
PubMed1996

High frequency of altered HLA class I phenotypes in invasive breast carcinomas.

We studied 105 tumor samples obtained from patients diagnosed as having breast carcinomas for HLA class I and II (DR) antigen expression, using a panel of mAbs defining HLA-monomorphic, locus-specific and allele-specific determinants. Peripheral blood lymphocytes from patients were also typed for HLA alleles. The results indicated total HLA class I losses in 55 patients (52.3%), HLA-A locus losses in four patients (3.8%), HLA-B locus losses in eight patients (7.6%), and A, B, locus losses in 10 patients (9.5%). The remaining 28 patients whose tissues reacted positively with monomorphic- and locus-specific mAbs were tested for HLA allelic losses using several anti-HLA mAbs defining A2, A3, A9, B8, B12, etc. Of these 28 patients, 16 (57%) showed one or more losses of HLA reactivity. These results indicated that in 88.5% of patients we detected a particular HLA-altered tumor phenotype. The downregulation of HLA class I antigens in breast carcinomas may thus be more frequent than previously reported, and patients without HLA class I downregulation may be the exception rather than the rule. It cannot be ruled out that HLA alterations are present in some of the 12 patients with an apparently normal HLA phenotype, as some HLA alleles could not be studied because of the lack of appropriate mAbs. These HLA alterations could represent an important step associated with tumor invasion, conferring to the tumor cells the ability to escape from T-lymphocyte recognition.

Antibodies, Monoclonal↗
PubMed1996

MHC class I antigens and tumour-infiltrating leucocytes in laryngeal cancer: long-term follow-up.

Alteration in MHC class I expression may be used by cancer cells to avoid immune destruction. Much experimental evidence supports this idea, although survival studies are very scarce. To investigate whether the presence or absence of HLA-A, -B and -C antigens in laryngeal carcinoma influences survival, a series of 60 primary laryngeal tumours treated surgically and normal tissues were evaluated in frozen sections for the expression of MHC class I antigens and tumour-infiltrating leucocytes (CD3, CD4, CD8, CD11b, CD1, CD20 and CD16), using monoclonal antibodies and the APAAP, technique. Long-term follow-up from the patients is available, ranging from 6 to 10 years. Thirteen tumours presented total HLA-ABC loss, five selective losses of HLA-A antigens and one absence of HLA-B antigens. Total losses were statistically associated with several clinical and pathological parameters, but there were no differences regarding tumour-infiltrating leucocytes. After conducting a prospective study, only T and N staging and scoring according to Glanz's malignancy classification were found to be independently related to patients' outcome. From our data, we conclude that neither complete loss of HLA class I antigens nor tumour-infiltrating leucocytes appear to influence survival in squamous cell carcinoma of the larynx.

Adult↗
PubMed1996

Effect of in vivo activation of natural killer (NK) cells by a tilorone analogue on the survival of mice injected intravenously with different experimental murine tumours.

We studied the effect of a tilorone analogue (RMI 10,874DA) and anti-asialo GM(1) serum on the survival of BALB/c and C57B1/6 mice after i.v. injections of different syngeneic murine tumour cells. Tumour lines used were different clones from chemically (GR9 wild type, GR9.B9, B7.1.B4, B7.1.B5, B7.2.38), and ultraviolet light (GRUV3)-induced sarcomas; B16 melanoma and LSTRA and YC8 lymphomas. Pretreatment of mice with tilorone inhibited metastatic colonization and increased survival significantly in all cases. In some tumour systems, the effect was attenuated when high numbers of cells were injected. Abrogation of NK cells with anti-asialo GM(1) serum significantly decreased (in all tumours and at different cell doses) survival in comparison with untreated mice injected with tumours, regardless of cell dose used. These results clearly suggest that NK cell activation in vivo by the tilorone analogue we tested prolongs survival and inhibits metastasis formation in mice, even when pretreatment consists of a single dose of the analogue.

Adjuvants, Immunologic↗
PubMed1996

HLA and cancer.

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Animals↗
PubMed1996

Loss of an HLA haplotype in pancreas cancer tissue and its corresponding tumor derived cell line.

A combination of immunohistochemical, biochemical, and recombinant DNA techniques were used to investigate class I expression in 26 pancreatic adenocarcinomas and 6 autologous tumor-derived cells. The prevalence of HLA losses was found to be comparable to that observed in other tumor types (> 35%), using monomorphic and locus-specific antibodies. In one patient, the original tumor tissue, a tumor derived cell line (IMIM-PC-2), and EBV-transformed lymphocytes were available for study. The patient's phenotype was A25, A30, B18, B18. However, A30 allele product could not be detected in the original tumor not in the cultured tumor cells. In addition, A30 allele could not be isolated from cDNA or genomic clones from the cultured tumor cells whereas it was isolated from the autologous lymphoblastoid cell line. Using isoelectric focusing analysis a significant reduction in the B18 heavy chain product was also observed in the tumor cell line, IMIM-PC-2, suggesting the absence of expression of one allele. Further studies revealed loss of heterozygosity at DR and other loci of chromosome 6 and cytogenetic data strongly suggested deletion of a full chromosome 6. This work indicates for the first time that loss of a full HLA haplotype occurs in tumor tissue and suggests that this mechanism may contribute to the progression of human cancer.

Adenocarcinoma↗
PubMed1996

Characterization of a gastric tumor cell line defective in MHC class I inducibility by both alpha- and gamma-interferon.

Alpha/beta and gamma type interferons (IFN), act through distinct cell surface receptors and induce transcription of an overlapping sets of genes. MHC class I genes are inducible by both type of interferons. We have analyzed a gastric tumor cell line, AGS, which was completely defective in MHC class I response to interferon-alpha and gamma. Northern blot analysis demonstrated that the lack of IFN response was related with the absence of up-regulation of specific HLA class I mRNA. Electrophoretic mobility shift assays in various tumor cell lines after IFN-alpha and IFN-gamma treatment showed differential binding of the transcriptional factors to MHC class I regulatory elements. Comparison of kappa-B binding activity showed that IFN-alpha and IFN-gamma induced opposite changes in NF-kappa B binding activity in AGS cells, indicating that the absence of MHC class I response in AGS appears to be independent of kappa-B activity. In contrast, there were remarkable differences in the level of transcriptional factor binding to an interferon-responsive sequence element (IRSE), between AGS and other interferon-responsive tumor cell lines. This result suggests that the low level of transcriptional factor binding to IRSE in AGS cells was responsible of the lack of induction of MHC class I antigens. In this context, overlapping factors in the signal transduction pathway of both type I and II interferons may be involved in the non-responsiveness of this gastric carcinoma tumor cell line.

Adenocarcinoma↗
PubMed1996

Prevalence and determinants of lead intoxication in Mexican children of low socioeconomic status.

This paper reports on the prevalence of lead poisoning in children between 1 and 5 years of age living in a marginal area to the north of Mexico City and also includes an evaluation of sources of exposure to this metal in the same area. The results show that 67.5% of the children studied have blood lead (PbB) levels > or = 10 micrograms/100 ml. Twenty-one percent of these children (1987) had PbB levels that required medical evaluation (> or = 20 micrograms/100 ml- < or = 40 micrograms/100 ml), and 112 children needed medical treatment (PbB > or = 40 micrograms/100 ml). In addition, the study found that the probability of higher blood lead levels (> or = 20 micrograms/dl) corresponds to children whose mothers use lead-glazed pottery dishes (OR = 2.80; CI 95%, 1.55-5.07) and to children who habitually bite colored pencils (OR = 2.05; CI 95%, 1.13-3.71) compared, respectively, with children whose mothers do not use that type of dishes and children who do not bite pencils. Our results provide baseline information for estimating the impact and costs of population-based interventions aimed at these populations and also confirm the need to strengthen health education programs to promote the reduction of lead exposure in the general population.

Child, Preschool↗
PubMed1996

Lymphocyte subpopulations and catecholamines; daytime variations and relationships.

The diurnal variations and their possible relations with endogenous catecholamines have been studied in 16 apparently healthy subjects (8 women and 8 men, between 22-35 years of age). A butterfly cannula was inserted into the flexure vein of the elbow at 8 h and at 20 h, a blood sample being taken after three 15-minute intervals. Leukocytes, lymphocytes, monocytes, and granulocytes were quantified in a cell counter while lymphocyte subpopulations were determined with flow cytometry in cells labelled with specific monoclonal antibodies. Plasma catecholamine concentrations were measured by high-pressure liquid chromatography. Significant differences for leukocyte circulating levels were found, as well as for all subpopulations measured at different times of day, save NK cells and monocytes. A statistically significant correlation was also found both between leukocytes, all subpopulations and epinephrine save B lymphocytes and NK cells, and between total lymphocytes, T lymphocytes, CD4, CD4/45RA+ subtypes and norepinephrine. In conclusion, diurnal rhythms were proved to exist in leukocyte and lymphocyte subpopulations; the significant correlation between these cells and catecholamine plasma levels suggests the presence of a possible mechanism that connects the cellular immunity with determined hormones.

Adult↗
PubMed1995

The dopamine D3 receptor and schizophrenia: pharmacological, anatomical and genetic approaches.

Antipsychotic drug therapy mainly rests on the use of antagonists of dopamine D2-like (D2, D3 and D4) receptors, for which all clinically active compounds have high affinity. The D3 receptor has a restricted expression in brain limbic areas, associated with cognitive functions and motivated behavior. D3 selective agonists and antagonists reveal an inhibitory role on motor behaviors for the D3 receptor, opposite to that of the D2 receptor. An opposing role for D2 and D3 receptors is also suggested by the contrasted effects of D2/D3 antagonists on neurotensin expression in discrete subdivisions of nucleus accumbens, where D2 and D3 receptors are selectively expressed. Tolerance to the motor but not to the therapeutic effects of neuroleptics is observed after repeated administration, which upregulates the D2, but not the D3 receptor in animals. In genetic association studies, an excess of homozygosity for both alleles of the BalI polymorphism at the D3 receptor gene was found in schizophrenic patients, suggesting that this gene may have subtle influence on the liability to develop schizophrenia. These results suggest the D3 receptor as an important target for antipsychotic drug action, and D3 receptor selective antagonists as promising therapeutic agents.

Animals↗
PubMed1995

Differential MAGE-1 gene expression in two variants of an erythroleukemic cell line (K562).

The MAGE-1 gene encodes an antigen recognized on melanoma cells by autologous cytotoxic T cells. This gene shows a wide range of expression in many human tumors but not in normal tissues except for testes. We used reverse transcription polymerase chain reaction assays to analyze the expression of the MAGE-1 gene in two variants of an erythroleukemic cell line, K562. Comparison of two variants of the K562 cell line in different stages of differentiation showed different patterns of expression of the MAGE-1 gene. The more undifferentiated cell line (K562A) expressed high levels of specific MAGE-1 mRNA, in contrast to K562B, which features of erythroid differentiation, without MAGE-1 expression. Interestingly, we could not modulate MAGE-1 gene expression when in vitro differentiation of K562A was induced with Ara-C. Finally, our data indicate that MAGE-1 expression is not necessary for the maintenance of the transformed phenotype.

Antigens, Neoplasm↗
PubMed1995

CD4+ cells in human ejaculates.

Using flow cytometry, we studied the expression of the CD4 antigen within the different cells present in human ejaculate, both in spermatozoa and round cells. In all, 20 samples of semen were obtained from fertile males; in 11 of these, we detected the presence of leukocytes, using the peroxidase test. Swim-up was performed for the analysis of the spermatozoa. From our results it may be concluded that there is no expression of the CD4 antigen on the surface of human spermatozoa or on CD45- ejaculate cells (epithelial and germinal cells). However, we did detect the presence of the CD4 antigen on the surface of the leukocyte cells (CD45+). A better characterization of these CD45+ cells made it apparent that the CD4+ cells of ejaculate are composed of T lymphocytes (helper/inducer T lymphocytes) and monocytes. Thus we may conclude that human spermatozoa do not express the CD4 antigen, the cell surface receptor for human immunodeficiency virus. However, we did detect CD4+ T lymphocytes and CD4+ monocytes in semen.

CD4 Antigens↗
PubMed1995

Biological implications of HLA-DR expression in tumours.

HLA-DR antigens show restricted tissue distribution in comparison with the more extensive expression of HLA class I molecules. This constitutive expression is genetically controlled by well-defined mechanisms. In addition, DR antigen expression can be induced by a variety of cytokines through different molecular genetic events that convert DR-negative epithelia into positive cells. In this review we analyse the two major pathological situations in which abnormal DR expression occurs: autoimmune diseases and tumour development. We hypothesize that conversion to DR-positivity may produce two opposite effects in both clinical situations: (1) a useful one in tumours associated with a good prognosis; and (2) a harmful one in autoimmune diseases with increased tissue damage.

Autoimmune Diseases↗