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Biomedical subjects

S Gómez

Publications and source records attributed to S Gómez.

At least 19 recordsLinked to original sources
PubMed2006

Respiratory system of Gluconacetobacter diazotrophicus PAL5. Evidence for a cyanide-sensitive cytochrome bb and cyanide-resistant cytochrome ba quinol oxidases.

In highly aerobic environments, Gluconacetobacter diazotrophicus uses a respiratory protection mechanism to preserve nitrogenase activity from deleterious oxygen. Here, the respiratory system was examined in order to ascertain the nature of the respiratory components, mainly of the cyanide sensitive and resistant pathways. The membranes of G. diazotrophicus contain Q(10), Q(9) and PQQ in a 13:1:6.6 molar ratios. UV(360 nm) photoinactivation indicated that ubiquinone is the electron acceptor for the dehydrogenases of the outer and inner faces of the membrane. Strong inhibition by rotenone and capsaicin and resistance to flavone indicated that NADH-quinone oxidoreductase is a NDH-1 type enzyme. KCN-titration revealed the presence of at least two terminal oxidases that were highly sensitive and resistant to the inhibitor. Tetrachorohydroquinol was preferentially oxidized by the KCN-sensitive oxidase. Neither the quinoprotein alcohol dehydrogenase nor its associated cytochromes c were instrumental components of the cyanide resistant pathway. CO-difference spectrum and photodissociation of heme-CO compounds suggested the presence of cytochromes b-CO and a(1)-CO adducts. Air-oxidation of cytochrome b (432 nm) was arrested by concentrations of KCN lower than 25 microM while cytochrome a(1) (442 nm) was not affected. A KCN-sensitive (I(50)=5 microM) cytochrome bb and a KCN-resistant (I(50)=450 microM) cytochrome ba quinol oxidases were separated by ion exchange chromatography.

Bacterial Proteins↗
PubMed2006

Expression of Snail protein in tumor-stroma interface.

The product of Snail gene is a repressor of E-cadherin transcription and an inductor of the epithelial-to-mesenchymal transition in several epithelial tumor cell lines. In order to examine Snail expression in animal and human tissues, we have raised a monoclonal antibody (MAb) that reacts with the regulatory domain of this protein. Analysis of murine embryos shows that Snail is expressed in extraembryonic tissues and embryonic mesoderm, in mesenchymal cells of lungs and dermis as well as in cartilage. Little reactivity was detected in adult tissues as Snail was not constitutively expressed in most mesenchymal cells. However, Snail expression was observed in activated fibroblasts involved in wound healing in mice skin. Moreover, Snail was detected in pathological conditions causing hyperstimulation of fibroblasts, such as fibromatosis. Analysis of Snail expression in tumors revealed that it was highly expressed in sarcomas and fibrosarcomas. In epithelial tumors, it presented a more limited distribution, restricted to stromal cells placed in the vicinity of the tumor and to tumoral cells in the same areas. These results demonstrate that Snail is present in activated mesenchymal cells, indicate its relevance in the communication between tumor and stroma and suggest that it can promote the conversion of carcinoma cells to stromal cells.

3T3 Cells↗
PubMed2006

Is it possible to reduce the number of endomyocardial biopsies with new immunosuppressive drugs?

INTRODUCTION: Using previous immunosuppressive regimens the considerable number of rejections of heart transplantations required routine surveillance myocardial biopsies, particularly during the early months. More effective immunosuppressive regimens would probably allow routine biopsies to be reduced. Our objectives were to assess the incidence of and the time to rejection with a new immunosuppressive protocol, considering the possibility of reducing the number of routine biopsies. MATERIALS AND METHODS: We undertook a retrospective study of patients who had undergone heart transplantation from January 2002 to August 2005 and who received induction therapy with Daclizumab (two doses) and maintenance therapy with tacrolimus + mycophenolate + low doses of steroids. RESULTS: Among 42 patients, 13 (31%) showed myocardial rejection in the first 3 months. All episodes were grade 3A and none had hemodynamic consequences. After 3 months, three patients (7.1%) experienced 3A rejection and 1 (2.4%), grade 4 acute rejection after ceasing medical treatment. Each episode of rejection was predictable, either owing to reduction in immunosuppression therapy or to a previous history of rejection. CONCLUSIONS: The majority of rejection episodes occur in the first 3 months posttransplantation. After that time, the incidence of rejection is less and clinically predictable. Therefore, surveillance biopsies should be limited to the first 3 months, and performed later either in symptomatic patients (with a history of previous rejection) or in those whose immunosuppressive therapy needs to be reduced.

Biopsy↗
PubMed2006

[Analysis of the reasons for consultation and dermatology care cost in a primary care site].

INTRODUCTION: The objective of the study was to the visits for esthetic reasons in an out-patient dermatology consultation and their cost and calculate the invoicing of these visits for a site other than the medical specialist consulted. METHOD: Prospective study in an out-patient dermatology clinic for 12 random days in February 2005. Endpoints of age, gender, diagnosis, cost per visit, cryotherapy and electrocoagulation were collected. Patients were divided into 3 groups: request for esthetic treatment (A), request for dermatology visit (B) and did not come (C). RESULTS: Group B was the largest, with 205 users (46 %), followed by C with 134/455 (29 %) and by A with 116/455 (25 %). In the latter group, the diagnoses were: seborrheic keratosis 39/455 (9 %), acrocordons 21/455 (5 %), remaining diagnoses (intradermal melanocytic nevi, cherry angioma, solar lentigos): 56/116 (11 %). The cost of these visits was 2,528. 8 euros in the 12 days analyzed and treatment of a subgroup of 85 patients (18.75 %) with cryotherapy or electrocoagulation increased it up to 5,043.80 euros. Estimated cost for one year would be 82,950 euros. Calculation of the invoicing for a non-public supplier site to the National Health Service would be: 8769.60 euros/month and 97,875 euros/year. If we add the treatments described, we go from 28,403.40 euros/month to 317,113.80 euros/year. CONCLUSIONS: These data and daily experience should make us think about the ethical consequences (do all the patients have to wait the same time?) as well as legal and collective ones (what type of dermatology do we want to specialize in?).

Costs and Cost Analysis↗
PubMed2005

Comparative study of muromonab-CD3 (OKT3) versus daclizumab (Zenapax) in cardiac transplantation at our center.

Recent studies support the addition of new immunosuppressive drugs as cytolytic induction therapy in cardiac transplantation. We carried out a comparative study comprising 52 patients who had undergone cardiac transplantation at our center. Thirty patients received muromonab-CD3 (OKT3, Janssen-Cilag, The Netherlands) as the induction therapy, whereas 22 patients received Daclizumab (Zenapax, Hoffman-La Roche, Nutley, NJ, USA) instead. All patients received cyclosporine or tacrolimus, mycophenolate, and steroids. Over an average follow-up period of 23.21 +/- 18 months, we analyzed retrospectively the incidence of grade > or = 3A biopsy-confirmed acute rejection episodes, the presence of infectious processes at 1 and 6 months, the occurrence of significant secondary effects, and the necessity to modify the immunosuppressive therapy during the follow-up. The results suggest that daclizumab is linked to a decreased incidence of grade > or = 3A biopsy-confirmed acute rejection and to a reduced necessity to modify the immunosuppressive therapy during the medium-term follow-up.

Antibodies, Monoclonal↗
PubMed2004

Macrophage derived signalling regulates negatively the megakaryocyte compartment.

Megakaryocytopoiesis is the process by which stem cells go through a process of commitment, proliferation and differentiation leading to the production of platelets. In the mouse, this process is accomplished within the bone marrow (BM) and spleen microenvironment and is carried out by regulatory molecules and accessory cells including macrophages, fibroblasts and endothelial-like cells. Previously, we have reported that macrophage depletion following administration of liposomal clodronate (LIP-CLOD) provokes enhancement of both, megakaryocytopoiesis and thrombocytopoiesis. In this report, we investigated the changes in the compartment of megakaryocyte progenitor cells (MK-CFU), their correlation with plasmatic thrombopoietin (TPO) and TPO transcription levels after macrophage depletion. LIP-CLOD-treated mice showed an increase of the MK-CFU in BM and spleen. Concerning TPO plasma levels, kinetic studies revealed a 1.5- and 1.3-fold increase in the TPO concentration at 12 and 24 hr of treatment. We also show evidence of regulation of TPO transcription in the liver and spleen. Although empty liposomes also enhanced TPO gene regulation in these organs, transcriptional TPO up regulation correlated with an increase of protein synthesis only in those animals where macrophages were effectively removed. Taken together, these results suggest that BM and spleen macrophages derived signalling regulates negatively the megakaryocyte compartment.

Animals↗
PubMed2003

Possible roles of magnesium on the immune system.

During the last few years, magnesium (Mg) has been subject of research due to its functionality in the organism. It is one of the most important micronutrients, and therefore its role in biological systems has been extensively investigated. Particularly, Mg has a strong relation with the immune system, in both nonspecific and specific immune response, also known as innate and acquired immune response. The aim of this paper is to review the state of the art about the interactions between Mg and the immune system. We discuss the link between dietary Mg and inflammation, apoptosis and alterations in number and function of innate immune cell populations, described in animal models. Furthermore, the immune system can be compromised in human populations under certain circumstances, including athletes and elderly people. The importance of a balanced Mg homeostasis and its interaction with the immune system in these groups has also been reviewed. Although emerging data support the relevant role of Mg in the immune response, further research is needed; and special efforts should be made to establish the most adequate dose in nutritional supplements to reach beneficial effects on health.

Aging↗
PubMed2002

The adaptive response of the immune system to the particular malnutrition of eating disorders.

Despite the seriously undernourished state of patients with anorexia nervosa (AN) and bulimia nervosa (BN), controversial findings have been published regarding some aspects of the immune system that are otherwise impaired in more typical types of malnutrition, such as protein-energy malnutrition. In general, adaptation processes seem to occur enabling immune function to be preserved during long periods of the illness. However, cell-mediated immunity is usually altered in AN and BN as reflected by lymphocyte subset counts and the response to delayed hypersensitivity tests. Regarding the helper/cytotoxic T cell ratio (CD4:CD8), an immunological marker of the nutritional status, the results of our studies on AN and BN patients showed that the duration of the eating disorder and the time when appropriate treatment is achieved are likely contributors to the alteration of this ratio. Despite these findings, it has been repeatedly pointed out that anorexic patients seem to be free of common viral infections at least until the most advanced stages of debilitation. Some hypotheses that could explain the lack of infection symptoms are reviewed. Cytokines and the altered acute phase response to infection, as well as cortisol and leptin, are considered to be potential factors involved in the adaptation processes occurring in these syndromes. Further progress in the knowledge of the psychoneuroendocrine-immune interactions established in AN and BN will be relevant to the understanding of the aetiology and maintenance mechanisms of these pathologies.

Adaptation, Physiological↗
PubMed2002

Probiotics as a help in children suffering from malnutrition and diarrhoea.

Malnutrition is associated with a significant impairment of cell-mediated immunity, phagocyte function, immunoglobulin A concentrations and cytokine production. This situation-which is unfortunately very frequent in infants and children from developing countries-leads to a high risk of infection, and often to episodes of diarrhoea, hence aggravating the nutritional status. Fermented milks are known to exert a beneficial influence on the host's health. They act by modulating gut microflora, regulating any alteration of gut mucosa and stimulating immune response. A number of studies have shown that probiotics shorten the duration of diarrhoea and prevent recurrence of other episodes. Furthermore, probiotics can prevent diarrhoea from infection in infants with malnutrition. In addition, it has been shown that cytokines could be used as biological markers of both impaired immune system and the immune stimulation of probiotics. The aim of this review is to update the effect of fermented milks in situations of malnutrition and diarrhoea as a consequence of infection as well as the role of cytokines produced by fermented milks in these deficient conditions.

Animals↗
PubMed2002

The effect of fermented milk on interferon production in malnourished children and in anorexia nervosa patients undergoing nutritional care.

For several years cytokine production has been associated with infections but it was not suspected that some types of food could also induce cytokines, even in a state of non-infection. Lactic bacteria can induce interferon (IFN) production in human healthy subjects, thus, a better protection against infections would be expected. Therefore, we planned to evaluate the effect of two diets including yoghurt or milk on IFN-gamma production during nutritional recovery in two different situations of malnutrition: (1) children with diarrhoea; and (2) patients with anorexia nervosa (AN). Both the diet including yoghurt of that including milk seemed to increase IFN-gamma production at the end of nutritional recovery in the malnourished children with diarrhoea. The significance of interferon production and the lymphocyte subset increase should be explored to know if a better resistance against pathogens is related to them. Regulation of intestinal absorption and moderate stimulation of interferon production make the yoghurt-based diet a good choice in the nutritional care of children. In the same way, an increase in the IFN-gamma production was observed in AN patients consuming yoghurt. This increase of IFN-gamma production could be considered a biological marker to detect the effect of probiotics on the immune response, especially in the improvement of a deficient nutritional status.

Adolescent↗
PubMed2001

The origin of hindered rotation around the Pt-N bond in platinum amides.

Several platinum amides of formula trans-[PtCl(NHAr)(PEt(3))(2)] (Ar = 3-FC(6)H(4), 2; 4-FC(6)H(4), 3; 4-ClC(6)H(4), 4; 4-IC(6)H(4), 5; 4-Cl,3-NO(2)-C(6)H(3), 6) have been synthesized by reaction of [PtHCl(PEt(3))(2)] with aryl azides. All the complexes feature planar arylamido moieties and hindered rotation around the N-aryl and Pt-N bonds have been detected and separately studied. The X-ray crystal structures of complexes 5 and 6 have been determined. Complex 5 crystallizes in the orthorhombic space group Pnma, with a = 23.806(4) A, b = 15.099(2) A, c = 6.7593(10) A, alpha = beta = gamma = 90 degrees, and Z = 4. Compound 6 shows an N-H...O(NO) hydrogen bond and it crystallizes in the monoclinic space group P2(1)/n, with a = 12.215(3) A, b = 8.078(2) A, c = 13.052(4) A, alpha = gamma = 90 degrees, beta = 90.057(6) degrees, and Z = 2. Except for Ar = 4-Cl,3-NO(2)-C(6)H(3), the activation energies obtained for the complexes indicate that both dynamic processes occur simultaneously with a common barrier which originates in the multiple bond character of the N-aryl bond due to a strong pi-donor behavior of the N atom in the N-aryl bond. The rotation about the Pt-N bond is unfavorable because of steric congestion with the planar amide, which can be overcome only when the aromatic ring can rotate. For the complex trans-[PtCl[NH(4-Cl,3-NO(2)-C(6)H(3))](PEt(3))(2)] the barrier to rotation is mostly due to hydrogen bond interaction between the NO(2) ortho substituent and the amide H atom.

Journal Article↗
PubMed2001

Evaluation of the zootechnical parameters of vaccinating against swine enzootic pneumonia under field conditions.

A field test was carried out in different production systems to evaluate the effect of vaccination against swine enzootic pneumonia with an inactivated vaccine. A total of 13,691 pigs of four different genetic origins were used, of which 7,351 were vaccinated and 6,340 were used as controls. The animals were housed in 16 fattening units, in which the 'one-site', 'two-site' and 'three-site' production systems were represented. There were the following statistically significant differences in favour of the vaccinated animals: a 1.89 per cent lower mortality (P<0.001), a 0.09 lower feed conversion ratio (P<0.030), a 3.12 per cent lower cost per kilogram gained in fattening (P<0.031), a 4.02 per cent lower cost per kilogram of carcase (P<0.018), a 3.77 per cent lower cost of feed per kilogram gained in fattening (P<0.012) and a 56.75 per cent lower potential loss of profit per kilogram gained in fattening due to mortality (P<0.001). An analysis of variance of the effects of genetic origin, treatment and production system on the different parameters showed that only the treatment had any statistically significant effect on the percentage mortality (P<0.002), feed conversion ratio (P<0.030), cost per kilogram gained in fattening (P<0.019), cost per kilogram of carcase (P<0.020), cost of feed per kilogram gained in fattening (P<0.015) and potential loss of profit per kilogram gained in fattening due to mortality (P<0.002).

Animal Husbandry↗
PubMed2001

Deletion or substitution of the aphthovirus 3' NCR abrogates infectivity and virus replication.

The 3' noncoding region (NCR) of the genomic picornaviral RNA is believed to contain major cis-acting signals required for negative-strand RNA synthesis. The 3' NCR of foot-and-mouth disease virus (FMDV) was studied in the context of a full-length infectious clone in which the genetic element was deleted or exchanged for the equivalent region of a distantly related swine picornavirus, swine vesicular disease virus (SVDV). Deletion of the 3' NCR, while maintaining the intact poly(A) tail as well as its replacement for the SVDV counterpart, abrogated virus replication in susceptible cells as determined by infectivity and Northern blot assays. Nevertheless, the presence of the SVDV sequence allowed the synthesis of low amounts of chimeric viral RNA at extended times post-transfection as compared to RNAs harbouring the 3' NCR deletion. The failure to recover viable viruses or revertants after several passages on susceptible cells suggests that the presence of specific sequences contained within the FMDV 3' NCR is essential to complete a full replication cycle and that FMDV and SVDV 3' NCRs are not functionally interchangeable.

3' Untranslated Regions↗
PubMed2001

Lepeophtheirus simplex sp. n., a caligid copepod (Siphonostomatoida) parasitic on "botete" (bullseye puffer, Sphoeroides annulatus) in Sinaloa, Mexico.

A new species of caligid copepod, Lepeophtheirus simplex sp. n., parasitic on bullseye puffer, Sphoeroides annulatus (Jenyns) in Sinaloa, Mexico is described. The new species is distinguished from its congeners by the possession of (1) a maxillule with simple dentiform process; (2) a sternal furca with sharply pointed, curved tines; (3) a 2-segmented exopod of leg 3 with simple, slender spine on proximal segment; (4) a 3-segmented exopod of leg 4 with a long proximal, outer spine; and (5) the terminal claw of male antenna with a large, tridentate, medial protuberance.

Animals↗
PubMed2000

Shiga toxin-2 induces neutrophilia and neutrophil activation in a murine model of hemolytic uremic syndrome.

It has been demonstrated that infections due to Shiga toxins (Stx) producing Escherichia coli are the main cause of the hemolytic uremic syndrome (HUS). Although it is recognized that Stx damage the glomerular endothelium, clinical and experimental evidence suggests that the inflammatory response is able to potentiate Stx toxicity. Lipopolysaccharides (LPS) and neutrophils (PMN) represent two central components of inflammation during a gram-negative infection. In this regard, patients with high peripheral PMN counts at presentation have a poor prognosis. Since the murine model has been used to study LPS-Stx interactions, we analyzed the effects of Stx alone or in combination with LPS on the kinetics of neutrophil production and activation and their participation in renal damage. We observed a sustained neutrophilia after Stx2 injection. Moreover, these neutrophils showed increased expression of CD11b, enhanced cytotoxic capacity, and greater adhesive properties. Regarding the cooperative effects of LPS on Stx2 action, we demonstrated potentiation of neutrophilia and CD11b induction at early times by pretreatment with LPS. Finally, a positive correlation between neutrophil percentage and renal damage (assayed as plasmatic urea) firmly suggests a role for PMN in the pathogenesis of HUS.

Animals↗
PubMed2000

[Primary stent implantation in aortic coarctation: mid-term follow-up].

BACKGROUND: The use of balloon-expandable stents provides an effective alternative therapy in patients with stenotic lesions in congenital heart disease. Stents implantation has served to improve the results and to reduce complications of balloon angioplasty for coarctation and recoarctation of the aorta. OBJECTIVE: We report our results after primary stents implantation for coarctation and recoarctation of the aorta. PATIENTS AND METHODS: Balloon-expandable stents were implanted in 14 patients (mean age 20 +/- 12 years) with coarctation of the aorta (11 native and 3 postoperative); 2 patients had associated malformations. The morphology varied: 10 resembled a located-diaphragm (one of them with moderate arch hypoplasia); 2 had distorted coarctation and 2 had a complete aortal obstruction. Five patients were hypertensive and 1 had cardiogenic shock and severe arrhythmias which did not respond to intensive medical therapy. In all cases 14 Palmaz stents (7 P308 and 7 P4014) were implanted with the primary technique through a Mullin's sheath. The balloon-to-descending aorta diameter ratio, measured at the level of the diaphragm, was 1. A special technique was carried out in the 2 cases with complete aortal obstruction. RESULTS: The procedure was effective in all 14 cases. The coarctation diameter increased from 4 +/- 2 to 15 +/- 2 mm (p < 0.0001) and transcoarctation systolic pressure gradient decreased from 43 +/- 19 to 2 +/- 2 mmHg (p < 0.0001). The ratio of the coarctation to descending aorta diameter measured at the level of the diaphragma increased from 0.3 +/- 0.1 to 0.95 +/- 0.05 (p < 0.001). At 19 +/- 8 months follow up, all patients showed sustained clinical improvement. The patient with complete aortal obstruction experienced a dramatic improvement, but she died from a sudden cardiac event 22 months after the procedure. At angiographic follow up in 7 patients, 1 year after implantation, no recoarctation was observed with secondary vessels patent, and absence of restenosis. CONCLUSIONS: a) Percutaneous endovascular stents implantation in coarctation and recoarctation of the aorta may become an effective treatment modality in the older child, adolescent and adults; b) stents are particularly attractive in those patients with a more complex anatomy and higher surgical risk; c) primary stenting is expected to have a lower rate of complications, and d) we describe a special technique with a right femoral-left humeral arterial circuit that is successfully applied to patients with complete aortal obstruction.

Adolescent↗