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Biomedical subjects

F Garrido

Publications and source records attributed to F Garrido.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

HLA-DR expression is associated with excellent prognosis in squamous cell carcinoma of the larynx.

We studied class II antigen expression and tumor-infiltrating leukocytes (TIL) in tissue sections of 69 squamous cell carcinomas of the larynx and 24 lymph node metastases in the neck. HLA-DR expression was found only in eight well-differentiated, highly keratinizing squamous cell carcinomas comprising seven of the verrucous variety and one ventriculosaccular tumor. None of the metastases was positive for DR antigen. Neither primary tumors nor autologous metastases stained for DP or DQ antigens. DR-positive tumors shared a peculiar pattern of TIL composed mainly of T cells, most of which belonged to the cytotoxic/suppressor subset, and B cells. These neoplasms had in common a slow rate of growth, and are considered low-grade carcinomas in the literature. We conclude from our study that HLA-DR expression seems to characterize tumors with a prominent infiltrate and an excellent prognosis.

Carcinoma, Papillary↗
PubMedDate not supplied

Mononuclear cell subpopulations in human follicular fluid from stimulated cycles.

The study of lymphocyte subsets from human follicular fluid (FF) provides an opportunity to evaluate immunological features of the ovary. We investigated the mononuclear cell subsets in FF and peripheral blood obtained at the time of laparoscopy from ten in vitro fertilization (IVF) patients. Midcycle nonpregnant peripheral blood was used as the control. A marked increase in the proportion of monocytes (CD14+) was observed in FF. Although FF was enriched with CD8+ lymphocytes, a decrease in the proportion of CD4+ lymphocytes was observed. "Memory" T cells in FF, identified by the CD4+ CD45R- phenotype, predominated over "naive" T cells (CD4+ CD45R+) at a ratio of 2:1, which differs from the ratio yielded by control blood samples (1:1). The percentage of activated T cells (CD3+ HLA-DR+ cell) increased significantly in FF. When lymphocyte subsets were studied in the peripheral blood of IVF patients, changes similar to but less significant than those in FF were found. These data support the concept that lymphocytes play an important role in ovarian physiology.

Antibodies, Monoclonal↗
PubMedDate not supplied

Immunogenicity of H-2 positive and H-2 negative clones of a mouse tumour, GR9.

The GR9 tumour was induced with methylcholanthrene in a BALB/c mouse, adapted to tissue culture and cloned without any passage in vivo GR9 clones were typed for H-2 with three monoclonal antibodies that define H-2Kd + Dd, Kd and Dd antigens. A great heterogeneity of H-2d expression was found from clones which were Kd and Dd positive to clones Kd and Dd negative. These results were confirmed for A7 and B9 clones using immunoprecipitation with anti-H-2D.4 and anti-H-2K.31 alloantisera and SDS-PAGE analysis. In addition, the number of chromosomes per cell was heterogeneous amongst the clones, ranging from 38 +/- 2 to pseudotetraploid clones which have 75 +/- 2 chromosomes. GR9 clones were injected into syngeneic BALB/c mice to measure local tumour growth. We found that the growth correlated with the amount of H-2 antigen expressed, i.e. clones with low H-2d expression were highly malignant while clones with normal H-2d expression were highly immunogenic. Finally we found that BALB/c mice immunized against A7 (Kd, Dd-positive) protected against A7, as expected, but surprisingly also against B9 (Kd, Dd-negative).

Animals↗
PubMedDate not supplied

Characterization of the syngeneic anti-tumour response against the GR9 tumour with the production of isoantisera and monoclonal antibodies.

Isoantisera and syngeneic monoclonal antibodies have been produced against A7, a clone derived from a BALB/c methylcholanthrene-induced tumour named GR9. The antigens defined by the isoantisera and mAbs are widely distributed in a large number of GR9 clones as well as in other tumour cell lines of different aetiology and origin. Two GR9 clones with marked differences in H-2 expression and syngeneic in vivo growth (A7, which is H-2d-positive and highly immunogenic and B-9, which is H-2d-negative and highly malignant) were selected to further analyse the presence or absence of the antigens recognized by the syngeneic anti-tumour antibodies. Immunoprecipitation data with two different isoantisera revealed a group of proteins with a molecular weight of Mr 65-70,000 present in both clones. Furthermore, immunoprecipitation with the A7-1 mAb again showed a single Mr 65K band present in A7 and B9 clones. We conclude that the marked differences observed in the syngeneic growth of the two clones are not due to differences in tumour associated antigens (TAA), defined by syngeneic antibodies, and emphasize the role that class I H-2 antigens could play in tumour rejection.

Animals↗
PubMedDate not supplied

Repression of class I H-2K, H-2D antigens on GR9 methylcholanthrene-induced tumour cell clones is related to the level of DNA methylation.

The correlation between gene expression and DNA methylation is well established. In the present study we examined DNA methylation as a potential regulatory mechanism of class I histocompatibility antigen expression. We selected for study two cell clones from the same mouse tumour (GR9). One of them is H-2 class I-positive (A7) and the other negative (B9). Using five enzymes and three different probes, no rearrangement or deletion was detected in the MHC class I genes of the negative clone compared with the positive one. These results do not provide an explanation for the differences observed in the expression of class I antigens in A7 (Kd, Dd positive) and B9 (Kd, Dd negative). We then studied the DNA methylation status in both clones by Southern blot analysis. Clear differences between the Kd, Dd positive and negative clones were detected. Furthermore, both Kd and Dd were clearly expressed after culturing the H-2 class I negative clone with the demethylating agent 5-azacytidine. These results suggest that the methylation of certain MHC cytosines is a regulatory mechanism of H-2 class I gene expression.

Animals↗
PubMedDate not supplied

Differential expression of HLA class I and II antigens in primary and metastatic melanomas.

Class I and II histocompatibility antigen expression was studied in cryostat sections of biopsy tissues from 15 patients diagnosed as suffering from malignant melanoma, using monoclonal antibodies against HLA class I and II monomorphic determinants and an indirect immunofluorescence technique. Class I antigens were detected in three of the four primary melanomas and in five of the eleven metastatic melanomas. Class II antigens were expressed only in metastatic melanomas, in three out of eleven cases. Some tumour cell suspensions were obtained and short-term cultures were established. Radiobinding and immunoprecipitation studies were carried out in two cases, named M6 and M8. The results were comparable to those obtained with direct immunofluorescence. We modulated the expression of class I and II HLA antigens with interferon in M6 when adapted to tissue culture. This melanoma was class I and II negative; after IFN gamma treatment it became strongly positive for class I and II antigens. In addition we have demonstrated, using Southern blot analysis with the restriction enzymes PvuII and EcoRI, that the M6 melanoma does not have any detectable alterations in its class II beta genes.

Adult↗
PubMedDate not supplied

Heterogeneity of the expression of class I and II HLA antigens in human breast carcinoma.

HLA class I and II antigen expression was studied in 19 cases of primary infiltrating ductal carcinoma of the breast. An indirect immunofluorescence technique was used on cryostat sections with monoclonal antibodies directed against HLA class I and II monomorphic determinants. Of the 19 cases studied, 17 were positive for class I antigen expression and two were negative. Class I HLA antigen expression was found to be clearly heterogeneous: in ten of these tumours more than 75% of the cells were class I positive; in two the percentage was decreased to between 50% and 75%; in five tumours it was less than 50%. With respect to class II HLA antigen expression, eight breast tumours were totally negative while two were strongly positive (50-75%) and the nine remaining cases were less than 25% positive. In addition, radioassay techniques were employed to determine the presence of oestrogen and progestagen receptors. The distribution of these receptors was not correlated with HLA class I or II antigen expression, nor could any relationship be demonstrated between the degree of histological differentiation of the tumours and their invasiveness.

Breast Neoplasms↗
PubMedDate not supplied

Generation of syngeneic anti-tumour double negative cells (CD4- CD8-), with cytotoxic activity against clones of different MHC class I expression.

In vivo immunization and secondary culture techniques were used to generate cytotoxic T lymphocytes against a tumour cell clone obtained from a methylcholantrene-induced fibrosarcoma. Our CTLs differed from classical CTLs (Ly2+ and MHC restricted) in that our lymphocytes exhibited a non-MHC restricted cytotoxic activity directed to the original tumour and to other MCA-induced tumours, but have failed to demonstrate any killing activity against a wide range of tumour cell lines of diverse origin (including NK sensitive targets). Depletion and phenotypic studies demonstrated that these cells bear the Thyl.2 antigen but are negative for both Ly2 and L3T4 antigens. These CTLs may belong to a double negative subset (CD4-, CD8-) involved in the anti-tumour response.

Animals↗
PubMedDate not supplied

MHC class I and II antigens on gastric carcinomas and autologous mucosa.

The expression of HLA class I and II antigens was analysed in 30 primary gastric carcinomas, 27 autologous lymph node metastases and 25 autologous gastric mucosae. We used an immune alkaline phosphatase technique on cryostatic sections and mAbs directed against HLA class I monomorphic determinants, HLA-B locus-specific products and HLA-DR, -DP and -DQ molecules. In addition HLA class I genes were analysed in tumour tissue and compared by Southern blots with the RFLP from autologous mucosa using locus-specific HLA probes. Finally the infiltrating mononuclear cells were studied on gastric tumours and adjacent mucosa with mAbs defining CD4, CD8 and CD11b differentiation antigens. The results obtained showed that three out of 27 primary gastric carcinomas completely lack HLA-ABC antigens (10%). In addition, two primary tumours presented a variable expression. The remaining 22 tumours presented a homogeneous positive HLA class I expression. Interestingly, when the autologous mucosa was analysed, only 12 out 25 specimens were homogeneously stained with mAbs against HLA class I antigens, suggesting that this tissue may lack the expression of HLA antigens before becoming malignant. Indeed, the majority of the gastric carcinomas studied presented a higher HLA-ABC antigenic expression than autologous mucosa. Finally, the HLA expression observed in the primary tumour was similar to that observed in autologous metastases. As a second part of the study we have found a direct relationship between the expression of HLA-DR antigens in mucosa and the intensity of inflammatory infiltration. This relationship was not maintained in the tumour tissue. In the mucosa the CD4-positive T cell was the predominant lymphocyte, while it was CD8 in the HLA-DR-positive tumours. Finally the RFLP of class I genes did not show any differences in any of the cases when compared with autologous mucosa. We included in these studies DNAs from HLA class I-negative tumours, HLA positive and HLA-B-negative ones.

Antibodies, Monoclonal↗
PubMedDate not supplied

c-K-ras overexpression is characteristic for metastases derived from a methylcholanthrene-induced fibrosarcoma.

We investigated the relationship between the activation of the c-myc and c-K-ras proto-oncogenes and the acquisition of metastatic potential in a methylcholanthrene-induced BALB/c fibrosarcoma. The murine fibrosarcoma GR9 was originally induced in BALB/c mice following exposure to the carcinogenic chemical 3-methylcholanthrene. To induce spontaneous metastasis, we used two tumor cell clones (B9 and G2) known to differ in their metastatic potential, local tumor growth, H-2 class I expression and sensitivity to natural killer (NK) cells. The metastatic nodes were obtained from the lung, liver and kidney. The results showed: (1) amplification of the c-myc proto-oncogene in original tumor clones as well as in all metastatic nodes; (2) mRNA overexpression without amplification of the K-ras proto-oncogene in the metastatic cells, regardless of their anatomical location; (3) no c-K-ras point mutations at codons 12 and 61, and (4) in general, a statistically significantly reduced in vitro sensitivity of metastatic tumor cells to NK cells as compared with the tumor clones used to induce them (p<0.05). These results therefore suggest that overexpressed c-K-ras mRNA is important during tumor progression, perhaps rendering metastatic tumor cells more resistant to lysis by NK cells.

Animals↗
PubMedDate not supplied

Detailed characterization of solute transport in a heterogeneous field soil.

There is a necessity for improved physical understanding of solute transport processes in heterogeneous soil systems. In situ nondestructive techniques like time domain reflectometry (TDR) and fiber optic miniprobes (FOMPs) permit the collection of unique measurements of solute transport processes in soils for the purposes of model development and validation. This study examined the application of TDR and FOMPs to measure solute transport at various points laterally and at two depths in a heterogeneous clay-loam soil. A miscible displacement experiment was performed at a constant irrigation flux to examine the applicability of these probes to field soils. In their first application to a field soil, the FOMPs were successfully calibrated and performed well in measuring solute breakthrough curves. Two flow regimes were identified in the soil profile, the first where lateral spreading of the solute occurred in the surface horizon, followed by convergence into preferential flow pathways in the second transport zone. The measured transport response was heterogeneous with at least two identifiable vertical flow phases. It was demonstrated using transfer function modeling and data from a corresponding laboratory study that the FOMPs were measuring the slower phase, while the TDR probes captured a composite of the fast and slow phases. The combination of these two techniques may be a means to separate solute transport phases in heterogeneous media and relate laboratory column results to field studies.

Fiber Optic Technology↗
PubMedDate not supplied

The biological consequences of altered MHC class I expression in tumours.

The identification of different mechanisms by which tumours escape from the immune system has helped to evaluate the clinical relevance of a variety of phenotypic changes that occur during tumour development. Among them, changes in HLA class I expression play a leading role in the tumour-host environment since HLA class I molecules interact with T lymphocytes for antigen presentation and with NK cells for inhibition/activation of these immune effector cells. Our laboratory has proposed a classification of the altered HLA class I phenotypes frequently found in human tumours, into five major groups. This review focuses on the tumour phenotypes found in primary and metastatic lesions, the molecular mechanisms that give rise to each phenotype and the clinical implications of these findings.

Alleles↗
PubMedDate not supplied

[Availability of essential medications at primary level units of the Health Department of Tamaulipas, Mexico].

OBJECTIVE: To describe the availability of some essential drugs at the primary health care units of the Ministry of Health of Tamaulipas, Mexico. MATERIAL AND METHODS: Between September and October 1998, all first level healthcare units of Tamaulipas' three sanitary jurisdictions were surveyed. Drug availability was assessed. The measurement instrument was a checklist of 56 drugs and 10 different supplies. For each drug and input the absolute number and the proportion of units with this drug or input was calculated. In the units where the drugs were available, the medians were calculated. The median of the total number of drugs available in all units was used as a global indicator. This same exercise was developed for each unit. Comparisons between the availability of these inputs in the units and stockrooms were also done. Stata 5.0 was used for statistical analysis. RESULTS: None of the inspected units had full availability of all checklist drugs. The highest percentage of drug availability was 84% and the lowest was 32%. There was limited availability of antibiotics, antihypertensive, hypoglycemic, and iron deficiency drugs. The availability of oral rehydration salts and contraceptive and vaccine agents was acceptable. CONCLUSIONS: Healthcare organizations must find alternative ways to improve access to drugs nationwide, in general, and availability of essential drugs in first level healthcare units, in particular. Two recent initiatives provide an optimistic outlook: decentralization of health services for the uninsured and the Generic Exchangeable Drugs Program, established nationwide in 1998.

Drugs, Essential↗
PubMedDate not supplied

[Immunologic modulation of tumor aggressiveness in cancer of the larynx. I. Genetic and molecular studies of HLA class I antigens].

A series of 60 primary laryngeal and hypopharyngeal tumours, 24 lymph node metastasis and normal tissue were evaluated in frozen sections for the expression of MHC class I antigens, using monoclonal antibodies. Normal distant mucosa of the larynx reacted to anti class I antibodies. In 13 primary tumours HLA class I antigens were not found. The remaining 47 showed a strong reaction to anti HLA-ABC (heavy chain) and anti beta 2-microglobulin, although in 5 cases staining was not observed with anti HLA-A locus specific monoclonal antibodies. Other tumour showed a selective loss of HLA-B antigens. These selective losses were confirmed using the correspondent anti-HLA polymorphic monoclonal antibodies. We have found differences in HLA class I expression when comparing primary tumours and autologous metastasis (3/15 cases). Finally, to further analyse the mechanism responsible for the HLA phenotypic changes observed, immunoprecipitation and SDS-PAGE of class I antigens, Northern and Southern blot analysis of MHC class I genes were performed. We have not detected class I gene rearrangement using HLA coding and locus specific non coding probes. However we have found a class I transcription defect in a class I negative tumour.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

[Immunologic modulation of tumor aggressiveness in cancer of the larynx. II. Clinicopathologic correlations with the loss of expression of the HLA ABC antigens].

A series of 60 primary laryngeal and hypopharyngeal tumours, 24 lymph node metastases and normal tissue were evaluated in frozen sections for the expression of MHC class I antigens, using monoclonal antibodies. We found 13 cases presenting total HLA-ABC losses, 5 selective losses of HLA-A antigens and 1 of HLA-B antigens. We were able to find statistical association between these losses and a number of clinical and pathological parameters, such as T and N stage, degree of differentiation, scores according to Jakobsson and Glanz grading systems, vascular invasion or leukocytic infiltrate. Our results lead us to the following conclusions: a) HLA class I losses were found in a group of tumours showing a greater aggressiveness and worse prognosis; b) these alterations in the expression are not associated with a increased metastatic potential. Thus, the absence of HLA molecules in laryngeal tumours is related to a greater local aggressiveness, and the loss of class I antigens seems to constitute and adaptive tumour mechanism to avoid the different anatomical and immunological barriers present in the laryngeal organ.

Adult↗
PubMedDate not supplied

[Postneonatal mortality caused by diarrhea: a case-control study].

A matched case-control study was undertaken in Naucalpan de Juárez, Estado de México. The goal of this study was to identify the risk factors for diarrheal disease in children between seven days and one year of age. We identified 63 case and 188 controls. The most important risk factors were: mother's age greater than 36 years with an odds ratis (OR) 3.7, lack of breastfeeding (OR 11.3), breast and bottle feeding (OR 5.4), lack of intradomiciliary sewage (OR 8.3), repeated episoded of disease (OR 8.6) and father's consumption alcoholic beverages (OR 3.6). The main possible paths by which these factors influence mortality are discussed. Specific interventions for some of the factors are proposed.

Case-Control Studies↗