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Biomedical subjects

M Redondo

Publications and source records attributed to M Redondo.

At least 19 recordsLinked to original sources
PubMed1999

Association of two silent polymorphisms of platelet glycoprotein Ia/IIa receptor with risk of myocardial infarction: a case-control study.

BACKGROUND: The platelet membrane glycoprotein Ia/IIa plays a major part in platelet function as a primary receptor for collagen. A previous report showed a variation of glycoprotein Ia/IIa receptor density and function associated with two silent and linked polymorphisms (807C/T and 873G/A) within the glycoprotein Ia gene. Because platelet thrombus formation is implicated in the pathogenesis of acute myocardial infarction, we investigated these polymorphisms among patients who had had a myocardial infarction. METHODS: We did a 2/1 case-control study including 177 patients (median age 57.0 [range 32-72] years) and 89 controls with same age and sex. Distributions of the 807C/T and 873G/A polymorphisms were investigated by genotyping DNA by PCR, single-strand conformation polymorphism analysis, and sequencing. FINDINGS: The prevalence of the homozygous 807T/873A genotype was 2.9 times higher among patients with myocardial infarction than among controls (16.4% vs 5.6%, p=0.022). There was an association between patients homozygous for the 807T/873A allele and myocardial infarction (odds ratio 3.3 [95% CI 1.2-8.8]), which was strongest in a subgroup of smokers. The homozygous 807T/873A genotype remained an independent risk factor for myocardial infarction (p=0.005) when age, sex, smoking, hypertension, diabetes, body-mass index, LDL-cholesterol and HDL-cholesterol, and fibrinogen were adjusted for by logistic regression. INTERPRETATION: The 807T/873A homozygosity of the platelet glycoprotein Ia/IIa gene polymorphism, associated with differences in surface collagen receptor density and activity, appears to be an independent risk factor for acute myocardial infarction. Our findings need to be confirmed in a larger, prospective study that includes patients from different populations and cardiovascular risk groups.

Adult↗
PubMed1999

Average optical performance of the human eye as a function of age in a normal population.

PURPOSE: To determine the average optical performance of the human eye, in terms of the modulation transfer function (MTF), as a function of age. METHODS: An apparatus was constructed to measure the ocular MTF, based on the recording of images of a green, 543-nm laser-point source after reflection in the retina and double pass through the ocular media. MTFs were computed from the average of three 4-second-exposure double-pass images recorded by a slow-scan, cooled charge-coupled device camera. The ocular MTF was measured for three artificial pupil diameters (3 mm, 4 mm, and 6 mm) with paralyzed accommodation under the best refractive correction in 20 subjects for each of three age categories: young subjects aged 20 to 30 years, middle-aged subjects aged 40 to 50 years, and older subjects aged 60 to 70 years. The selected subjects passed an ophthalmologic examination, excluding subjects with any form of ocular or retinal disease, spherical or cylindrical refractive errors exceeding 2 D, and corrected visual acuity lower than 1 (0.8 in the older age group). RESULTS: The average MTF was determined for each age group and pupil diameter. A two-parameter analytical expression was proposed to represent the average MTF in each age group for every pupil diameter. The ocular MTFs declined as age increased from young to older groups. The SD of the MTF results within age groups was lower than the differences between the mean for each group. CONCLUSIONS: The average optical performance of the human eye progressively declines with age. These MTF results can serve as a reference for determining mean ocular optics according to age.

Adult↗
PubMed1998

The bovine IFN-omega 1 is biologically active and secreted at high levels in the yeast Pichia pastoris.

The gene coding for bIFN-omega 1 was isolated from bovine genomic DNA by polymerase chain reaction (PCR). Recombinant bIFN-omega 1 was expressed in the yeast Pichia pastoris and high levels of the recombinant protein (0.4 mg ml-1) were secreted to the culture media. The obtained bIFN-omega 1 showed a cross-species antiviral activity on four mammalian cell lines of calf, pig, hamster and human origin, but this activity was absent on Madin-Darby canine kidney (MDCK) cells. A delivery carrier was developed to permit a better release of bIFN-omega 1. When compared with a control group, an increase in 6 days in the corpus luteum lifespan was obtained in cyclic ewes following three interferon (IFN) intrauterine administrations on days 9, 10 and 11 post-estrus. In summary, these results demonstrated for the first time that biologically active recombinant bIFN-omega 1 was highly secreted by P. pastoris showing antiviral activity in different cell lines and an antiluteolytic effect in cyclic ewes, with no detrimental effects on the animals.

Amino Acid Sequence↗
PubMed1998

Dexamethasone induces altered binding of regulatory factors to HLA class I enhancer sequence in MCF-7 breast tumour cell line.

Several reports have shown the importance of MHC class I antigens in enabling the host to regulate tumour growth in vivo. Glucocorticoid hormones have strong immunosuppressive effects and are known regulators of gene transcription. In this work we studied the expression of major histocompatibility complex (MHC) class I antigens in three breast carcinoma cell lines before and after treatment with the synthetic glucocorticoid dexamethasone. HLA class I expression in the cell line MCF-7 was down-regulated in the presence of dexamethasone. This down-modulation of expression appeared to be mediated by transcriptional mechanisms, as revealed by HLA class I mRNA levels. To elucidate the basis of MHC class I down-regulation by dexamethasone, we examined transcriptional-factor-binding activity to the HLA class I regulatory element or enhancer A by electrophoretic-mobility-shift assays, using synthesized oligonucleotides corresponding to upstream conserved sequences of MHC class I genes. Our results showed that dexamethasone induced a different binding to the MHC class I regulatory elements in the MCF-7 cell line from that of the other cell lines included in our study. MCF-7 cells presented a strong decrease in previous factor-binding activity to the CRE II probe (H2RIIBP-like binding activity) and a new factor-binding activity was apparent. On the other hand, CRE I region showed an increase in KBF1-factor-binding activity. These results suggest that glucocorticoids down-modulate the expression of MHC class I antigens by altering the binding to the enhancer A sequence. In addition, this down-modulation may affect the regulation of tumour growth by the host's immune system.

Breast Neoplasms↗
PubMed1998

Field studies and cost-effectiveness analysis of vaccination with Gavac against the cattle tick Boophilus microplus.

The control of tick infestations and the transmission of tick-borne diseases remains a challenge for the cattle industry in tropical and subtropical areas of the world. Traditional control methods have been only partially successful and the parasites continue to result in significant losses for the cattle industry. Recently, vaccines containing the recombinant Boophilus microplus gut antigen Bm86 have been developed. These vaccines have been shown to control tick infestations in the field. However, extensive field studies investigating the efficacy and cost-effectiveness of vaccination have not been reported and are needed to appraise the effect of this new approach for tick control. Here is reported the results of the application of Gavac in a field trial including more than 260,000 animals in Cuba. In this study the correlation between the antibody response to vaccination and the effect on ticks fertility is determined. Physiological status of the animals was found to affect the primary response to vaccination but not the antibody titers after revaccination. A cost-effectiveness analysis showed a 60% reduction in the number acaricide treatments, together with the control of tick infestations and transmission of babesiosis, which resulted in savings of $23.4 animal-1 year-1. These results clearly demonstrate the advantage of vaccination and support the application of Gavac for tick control.

Animals↗
PubMed1998

Effect of particulation on the immunogenic and protective properties of the recombinant Bm86 antigen expressed in Pichia pastoris.

The recombinant Bm86 tick antigen expressed in Pichia pastoris is obtained in a highly particulated form, as a distinguish feature of this expression system. This particulated protein, the active principle of the recombinant vaccine Gavac against the cattle tick, have shown high immunogenic and protective properties, probably associated with its own characteristics. To evaluate the effects of particulation on the properties of Bm86, three groups of calves were immunized with particulated or non-particulated recombinant Bm86 and the anti-Bm86 antibody response determined. Animals were challenged with a controlled tick infestation and the protective capacities of both proteins assessed. Humoral immune response and protection in cattle vaccinated with the particulated antigen were higher. These experiments suggested that particulation of the Bm86 expressed in P. pastoris is an important feature for the protective properties of the antigen in vaccine preparations.

Animals↗
PubMed1998

Protection against Boophilus annulatus infestations in cattle vaccinated with the B. microplus Bm86-containing vaccine Gavac. off.

Tick infestations by Boophilus spp. constitute a major problem for the cattle industry in tropical and subtropical areas of the world. The use of traditional control methods has been only partially successful and tick infestations remain a serious problem. Recently, the gut antigen Bm86 was isolated from B. microplus. Recombinant preparations of this antigen have been used in vaccines for the control of B. microplus infestations. However, in several regions of the world, B. microplus coexists with other Boophilus species, mainly B. annulatus and B. decoloratus. Therefore, there is a need for the simultaneous control of infestations by different Boophilus species. To test the capacity of the P. pastoris-derived Bm86 antigen preparation (Gavac, Heber Biotec S.A., Havana) to control B. annulatus infestations, controlled experiments were conducted in Mexico and Iran. Cattle were vaccinated with Gavac or not vaccinated and then artificially infested with B. annulatus larvae. The results showed for the first time a high protection efficacy (> 99.9%) of Gavac in the control of B. annulatus infestations. These results support the application of Bm86-containing vaccines for the control of Boophilus spp. infestations.

Animals↗
PubMed1998

Differential expression of MHC class II genes in lung tumour cell lines.

Molecular characterization of HLA class II expression was investigated in five lung tumour cell lines at the protein and mRNA levels. The cell lines exhibited a differential expression of HLA-DR, HLA-DP and HLA-DQ products and also showed differences in the inducibility of HLA class II genes by gamma-IFN. Gamma-IFN stimulation induced only HLA-DR expression to varying degrees in three cell lines, while only one cell line showed stimulation for HLA-DP and none for HLA-DQ antigens. These results suggest locus-specific regulation for the three loci. The presence of DR protein on the cell-surface membrane was always positively correlated with the presence of HLA-DR mRNA in the cells. After treatment with 5-azacytidine in the A549 cell line, which expressed the lowest values, there was no effect on HLA class II levels. This suggested that methylation does not play an important role in the lack of MHC class II antigen expression. In addition to studying mRNA levels of HLA class II antigens, we analysed mRNA of the proto-oncogene c-myc and observed a positive correlation of two mRNA: the increments in HLA-DR expression were associated with increments in c-myc expression. This suggests a relationship between the regulatory and HLA-DR antigens control the expression of c-myc and HLA-DR antigens in lung tumour cell lines.

Actins↗
PubMed1998

Increase of large granular lymphocytes in human ejaculate containing antisperm antibodies.

Using flow cytometry, we studied the expression of the CD16 antigen by lymphocytes present in human semen samples from three groups of patients: 60 fertile men attending for vasectomy, 60 sterile patients without antisperm antibodies (ASA) and 18 immunological sterile patients with ASA in their ejaculate. No significant difference was found in the concentration of leukocytes or subpopulations of these cells (monocytes, lymphocytes and granulocytes) between fertile, sterile without ASA and immunological sterile groups. However, we detected a predominance of macrophages/monocytes within the population of seminal leukocytes. No statistically significant difference was found in the absolute number of T and B lymphocytes between the three groups studied. However, a significant increase in the number of CD16+ lymphocytes was observed in the ejaculate of sterile patients with ASA as compared to the other groups. This finding might establish an important parameter in the follow-up and prognosis of patients with immunological sterility.

Adult↗
PubMed1998

Thyroid function in acute pancreatitis.

OBJECTIVES: To analyze changes in the thyroid function in patients with acute pancreatitis. METHODS: Admission serum levels of triiodothyronine (T3), reverse triiodothyronine (rT3), thyroxine (T4) and thyrotropin (TSH) were determined in 20 patients with pancreatitis and 20 healthy control patients. Another group of 20 patients with upper digestive haemorrhage was included to study possible changes in the pattern of thyroid function in hemodynamic alterations. In addition, laboratory indicators of liver, renal and pancreatic functions were measured in all groups. RESULTS: Our results demonstrated low levels of T3 in 20% of patients with pancreatitis and increased rT3 levels in 75% of them. Thyrotropin was always among reference ranges and only one case presented a low level of T4. No significant alterations were detected in patients with upper digestive haemorrhage. CONCLUSIONS: These results suggest that pancreatitis may play a role in the genesis of these changes, since other factors such as diet and cellular hepatic alteration appear to have had no effect on the levels of thyroid hormones in these patients. In other studies those changes in the thyroid function can be relationed with the prognosis in acute pancreatitis.

Acute Disease↗
PubMed1998

On the automaticity of ipsilateral response activation in the Simon effect.

The effects on performance of unattended stimulus-response spatial relationships in choice reaction time tasks (i.e., the Simon effect) have been attributed to automatic activation of the response ipsilateral to stimulus location. We tested this assumption using the lateralized readiness potential (LRP). The response key labels changed randomly from trial to trial and were presented either 400 ms before (immediate-reaction trials) or 400 ms after (delayed-reaction trials) stimulus. The critical test for the automatic activation hypothesis was on delayed-reaction trials, in which LRP deflections were expected in the interval between stimulus and response-key labels. Contrary to this prediction, there were no LRP signs of response activation within that interval.

Adult↗
PubMed1997

The effects of the degree of surgical trauma and glucose load on concentration of thyrotropin, growth hormone and prolactin under enflurane anaesthesia.

Sixty patients undergoing gynecological surgery under enflurane nitrous-oxide anesthesia were studied. The goal was to investigate the effects of the degree of surgical trauma and glucose load on the pattern of TSH, GH and PRL secretion before, during and following surgery. For this purpose the patients were divided into four groups according to the severity of the operation and the type of fluid administered. The groups were as follows: group 1, major surgery--glucose solution; group II, major surgery--lactated Ringer solution; group III, minor surgery--glucose solution; group IV, minor surgery--no intravenous fluids. The three hormone concentrations, 45 min after the start of anesthesia, increased in all groups. The highest values for GH and PRL concentration were observed in group IV. This increase was followed by a decrease 24 h and 5 days after induction, at the end of the study, except in group IV where TSH and GH levels fell back to normal values more slowly. These results lead to the following conclusions: a) Enflurane does not suppress hormonal stress response to surgical trauma; b) A similar pattern is obtained for pituitary response, indicating that a general pituitary stimulus takes place in these situations; c) Glucose load plays an important role in pituitary hormonal response to surgical stress; d) There is no direct relationship between the degree of surgical trauma and the hormone levels in patients under enflurane anaesthesia.

Adult↗
PubMed1997

Class I major histocompatibility complex antigens and tumor ploidy in breast and bronchogenic carcinomas.

We determined the frequency of expression of the major histocompatibility complex antigens HLA-A,B,C in tumor cells from 207 primary tumor lesions of breast and bronchogenic carcinomas, to see if the expression of theses antigens was linked with several clinicopathological parameters associated with tumor aggressivity, such as abnormal cellular DNA content. We compared tumor tissues with nonneoplastic tissues and tissues from 15 benign breast lesions. HLA class I expressor and nonexpressor tumor cells were determined by using immunohistochemical stains (PAP and APAAP methods) and antibodies against these antigens. Reduction of HLA class I antigen was detected in 65 tumors (31.7%) and was significantly associated with poor tumor differentiation and abnormal cellular DNA content (p < 0.001). These characteristics might define a group of aggressive tumors in which the decrease of HLA class I antigens would enable tumor cells to avoid eliciting host immune responses. On the other hand, the altered regulatory mechanisms, of tumors with abnormal cellular DNA content, might modulate the expression of HLA class I molecules.

Breast Neoplasms↗
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

Downmodulation of HLA class I expression by dexamethasone in MCF-7 cell line.

Several reports have shown the importance of MHC class I antigens in enabling the host to regulate tumour growth in vivo. Glucocorticoid hormones have strong immunosuppressive effects and are known to be regulators of gene transcription. In this report the expression of Major Histocompatibility Complex (MHC) class I antigens in six breast carcinoma cell lines have been studied before and after treatment with the synthetic glucocorticoid dexamethasone. Hence, HLA class I expression in the MCF-7 cell line was down-regulated in the presence of dexamethasone. This down-modulation of expression appeared to be mediated by transcriptional mechanisms, as revealed by HLA-class I mRNA levels.

Breast Neoplasms↗
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↗
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↗