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C Pérez

Publications and source records attributed to C Pérez.

At least 19 recordsLinked to original sources
PubMed2006

Role of receptor interaction in the mode of action of insecticidal Cry and Cyt toxins produced by Bacillus thuringiensis.

Cry toxins from Bacillus thuringiensis are used for insect control. Their primary action is to lyse midgut epithelial cells. In this review we will summarize recent findings on the Cry toxin-receptor interaction and the role of receptor recognition in their mode of action. Cry toxins interact sequentially with multiple receptors. In lepidopteran insects, Cry1A monomeric toxins interact with the first receptor and this interaction triggers oligomerization of the toxins. The oligomer then interacts with second receptor inducing insertion into membrane microdomains and larval death. In the case of mosquitocidal toxins, Cry and Cyt toxins play a part. These toxins have a synergistic effect and Cyt1Aa overcomes Cry toxin resistance. Recently, it was proposed that Cyt1Aa synergizes or suppresses resistance to Cry toxins by functioning as a membrane-bound receptor for Cry toxin.

Bacillus thuringiensis↗
PubMed2006

Phenotypic and functional characterization of porcine granulocyte developmental stages using two new markers.

Here, we describe two new surface antigens, named 6D10 and 2B2, whose expression is restricted to porcine granulocytes. 6D10 is only detected in neutrophils and its expression decreases from promyelocytes to mature cells. By contrast, 2B2 antigen is selectively expressed in mature neutrophils, eosinophils and basophils. The expression of these antigens along granulocyte maturation allows the discrimination of several developmental stages of granulocytes based on phenotypic, morphological and functional characteristics previously established. Moreover, these new markers are useful tools to easily characterize the different granulocytes lineages (neutrophils, eosinophils and basophils). By using multiparameter flow cytometric analysis, we have performed a phenotypic and functional characterization of the granulocyte subsets identified by the combination of 6D10 and 2B2 antigens.

Animals↗
PubMed2006

A very efficient bioconversion of soybean phytosterols mixtures to androstanes by mycobacteria.

The production of several high value steroid drugs, used as progestational, adrenocortical, estrogenic and contraceptive agents, is mostly derived from 4-androstene-dione (AD) and 1,4 androsta-diene-3,17-dione (ADD). Three Vietnamese phytosterols mixtures named VN-1, VN-2 and VN-3, isolated from soybean oil may be efficiently converted into these key compounds by mycobacterial cells. Their general phytosterol composition was 55.39, 70.55, 70.19% for VN-1, VN-2 and VN-3, respectively. Moreover, values of campesterol, beta-sitosterol and stigmasterol were determined. After 120 h of shaking in suitable culture media and temperature, maximal yield conversion to ADD was higher than 70% and up to 64% to AD, for the various phytosterols mixtures assays. These results may be better when scaling-up such a procedure of phytosterols conversion.

Androstanes↗
PubMed2006

Effect of docosahexaenoic acid administration on plasma lipid profile and metabolic parameters of children with methylmalonic acidaemia.

AIM: To evaluate the effect of administration of docosahexaenoic acid (DHA) on dyslipidaemia, plasma fatty acid composition and metabolic parameters of children with isolated methylmalonic acidaemia (MMA) (McKusick 25100). METHODS: Four children (3 male, 1 female) with MMA (mut(0)), participated in a crossover, randomized study of DHA administration (25 mg/kg per day, divided into three daily doses). The control group comprised 56 healthy children, aged 10+/- 2.7 years, (51 male, 5 female), who were followed in our clinic owing to possible familial risk of cardiovascular disease. RESULTS: The comparison of plasma fatty acid composition of children with MMA versus control children demonstrated that the patients had significantly higher values for oleic acid (p = 0.004) and linolenic acid (p = 0.008). No differences were observed in the levels of DHA and arachidonic acid. Plasma concentrations of insulin, glycine, ammonia, total cholesterol and cholesterol fractions did not change with DHA administration. No significant changes were observed in urinary excretion of methylmalonic acid. As expected, the percentage of DHA and n-3 fatty acids in plasma increased significantly after therapy (p = 0.005 and 0.014, respectively). The most remarkable result was a decrease of plasma levels of triglycerides after DHA therapy (p = 0.014). CONCLUSION: As previously found in normal children, dietary supplementation with DHA decreases the triglyceride levels, normalizing the hypertriglyceridaemia of these children without any evidence of short-term adverse effects.

Adolescent↗
PubMed2005

A case study of elemental and structural composition of dental calculus during several stages of maturation using SRXRF.

This work presents a study of elemental composition and preponderant structure of human dental calculus, as they mature in the mouth for a period of 1 year. The synchrotron radiation X-ray fluorescence technique using a white beam was employed as an analytical method. The set of samples were extracted from different dental elements of the same subject, who did not require any other clinical care. By means of analyzing the Ca/P molar ratio an estimation of the main crystallographic structure was attained, by simple comparison with stoichiometric values of the several crystalline structures that compose the calculus. The results showed a slowly progressive transformation of the initial crystalline structures (brushite) into more stable structures (hydroxyapatite), passing through octacalcium phosphate and whitlockite. The concentrations of mayor components (Ca and P) as a function of time followed a sigmoid curve. The analysis of trace element concentrations versus time indicated a null or small correlation of concentration values with the kinetics of the crystallization process.

Crystallography, X-Ray↗
PubMed2005

Anti-inflammatory activity of Lippia dulcis.

Lippia dulcis hexane and ethanol extracts were tested for its anti-inflammatory activity in several animal models. Hexane extract showed to be inactive, but the ethanol extract at doses of 400 mg/kg produced significant inhibition of carrageenan-induced paw oedema and reduced the weight of cotton pellet-induced granuloma, moreover, the topical application of 0.5 mg/ear of this extract inhibited the edema induced with TPA by 49.13%, an effect which is of less intensity than that produced by indomethacine at the same dose.

Animals↗
PubMed2005

Association of pretreatment serum interferon gamma inducible protein 10 levels with sustained virological response to peginterferon plus ribavirin therapy in genotype 1 infected patients with chronic hepatitis C.

BACKGROUND: Increased serum and intrahepatic interferon gamma inducible protein 10 (IP-10) levels in patients with chronic hepatitis C (CHC) have been described. AIM: To analyse the possible association of serum IP-10 levels with different outcomes to antiviral therapy. PATIENTS: A total of 137 CHC patients treated with peginterferon plus ribavirin. METHODS: Serum IP-10 levels were determined by enzyme linked immunosorbent assay before therapy, after 12 weeks of treatment, and 24 weeks after cessation of therapy. Variables significantly associated with a sustained virological response (SVR) on univariate analysis were included in a multivariate logistic regression model. RESULTS: Pretreatment serum IP-10 levels in patients with SVR were significantly lower than in non-responders (NR) (332.4 (222.1) v 476.8 (305.3) pg/ml, respectively; p=0.004). Serum IP-10 concentrations significantly decreased in patients with SVR (pretreatment: 332.4 (222.1) pg/ml; post-treatment: 170.2 (140.1) pg/ml; p<0.001) but not in NR (pretreatment: 476.8 (305.3) pg/ml; post treatment: 387.3 (268.1) pg/ml; p=0.06). By multivariate analysis, non-1 genotype (odds ratio (OR) 3.5 (95% confidence interval (CI) 1.1-10.4); p=0.003) and low viral load at baseline (OR 0.34 (95% CI 0.14-0.79); p=0.01) were independent predictors of SVR in all patients. When multivariate analysis was restricted to patients with genotype 1, only baseline viral load (OR 0.38 (95% CI 0.155-0.96); p=0.04) and pretreatment serum IP-10 levels (OR 0.99 (95% CI 0.996-0.999); p=0.03) were identified as predictive factors of SVR. CONCLUSION: Pretreatment serum IP-10 behaves as a predictive factor of SVR to peginterferon plus ribavirin therapy in genotype 1 infected patients.

Adult↗
PubMed2005

Supramolecular aggregation of two hydroxycarboxylic acid derivatives.

The crystal structures of 7,7-dicyclobutyl-5-hydroxymethyl-6-oxabicyclo[3.2.1]octane-1-carboxylic acid, C17H26O4, (I), and 1-(hydroxymethyl)-7-oxaspiro[bicyclo[3.2.1]octane-6,1'-cyclopentane]-5-carboxylic acid, C13H20O4, (II), determined at 170 K, show that the conformation of the hydroxymethyl group (anti or gauche) affects the dimensionality (one- or two-dimensional) of the supramolecular structures via O-H...O hydrogen bonds. In (I), the carboxyl and hydroxymethyl groups interact with themselves, forming a one-dimensional step-ladder, while in (II), a two-dimensional structure is made up of carboxylic acid centrosymmetric R(2)2(8) dimers connected by hydroxyl-to-ether contacts.

Journal Article↗
PubMed2005

Bioconversion of phytosterols to androstanes by mycobacteria growing on sugar cane mud.

Direct sterol conversion of sugar cane mud (residue) by Mycobacterium sp. was demonstrated to be possible technologically, thus avoiding sugar cane oil extraction and further processes of extraction and purification of phytosterols from this oil. Indeed, mycobacterial cells were able to convert phytosterols from sugar cane mud into 4-androstene-dione (AD) and 1,4 androsta-diene-3,17-dione (ADD). For the various concentrations assayed, concomitant higher yields for both androstanes were achieved at 20% (w/w) sugar cane mud in media. Furthermore, conversions were similar to those from other substrates, such as a mixture of phytosterols. The results suggest that the mycobacterial cell is able to easily access and bioconvert sugar cane mud phytosterols.

Androstanes↗
PubMed2005

Hydrogen-bonding patterns of two dihydroxylactone derivatives.

In the hydrogen-bonding networks of 8-hydroxy-5-hydroxymethyl-3,6-dioxatricyclo[6.3.1.0(1.5)]dodecan-2-one and 5,7-bis(hydroxymethyl)-3,6-dioxatricyclo[5.3.1.0(1.5)]undecan-2-one, both C11H16O5, layers and double strands, respectively, lead to the formation of chains connected by hydroxy-to-hydroxy contacts, where the hydroxymethyl group, present in both structures, acts as a donor. The secondary structures differ in the hydrogen bonding of these chains via the second hydroxy group, which is involved in hydroxy-to-carbonyl and hydroxy-to-hydroxy bonds, respectively.

Journal Article↗
PubMed2005

CT features of abdominal plasma cell neoplasms.

The aim of this study was to describe the CT features of abdominal plasma cell neoplasms. We reviewed CT imaging findings in 11 patients (seven men, four women; mean age 62 years) with plasma cell neoplasms and abdominal involvement. Helical CT of the entire abdomen and pelvis was performed following intravenous administration of contrast material. Images were analyzed in consensus by two radiologists. Diagnoses were made from biopsy, surgery and/or clinical follow-up findings. Multiple myeloma was found in seven patients and extramedullary plasmacytoma in four patients. All patients with multiple myeloma had multifocal disease with involvement of perirenal space (4/7), retroperitoneal and pelvic lymph nodes (3/7), peritoneum (3/7), liver (2/7), subcutaneous tissues (2/7) and kidney (1/7). In three of the four patients with extramedullary plasmacytoma, a single site was involved, namely stomach, vagina and retroperitoneum. In the fourth patient, a double site of abdominal involvement was observed with rectal and jejunal masses. Plasma cell neoplasm should be considered in the differential diagnosis of single or multiple enhancing masses in the abdomen or pelvis. Abdominal plasma cell neoplasms were most frequently seen as well-defined enhancing masses (10/11).

Abdominal Neoplasms↗
PubMed2005

T-kininogen can either induce or inhibit proliferation in Balb/c 3T3 fibroblasts, depending on the route of administration.

T-kininogen (T-KG) is a precursor of T-kinin, the most abundant kinin in rat serum, and also acts as a strong and specific cysteine proteinase inhibitor. Its expression is strongly induced during aging in rats, and expression of T-KG in Balb/c 3T3 fibroblasts results in inhibition of cell proliferation. However, T-KG is a serum protein produced primarily in the liver, and thus, most cells are only exposed to the protein from the outside. To test the effect of T-KG on fibroblasts exposed to exogenous T-KG, we purified the protein from the serum of K-kininogen-deficient Katholiek rats. In contrast to the results obtained by transfection, exposure of Balb/c 3T3 fibroblasts to exogenously added T-KG leads to a dose-dependent increase in [3H]-thymidine incorporation. This response does not require kinin receptors, but it is clearly mediated by activation of the ERK pathway. As a control, we repeated the transfection experiments, using a different promoter. The results are consistent with our published data showing that, under these circumstances, T-KG inhibits cell proliferation. We conclude that T-KG exerts opposite effects on fibroblast proliferation, depending exclusively on the way that it is administered to the cells (transfection versus exogenous addition).

Aging↗
PubMed2005

[Frequency and risk factors of voice disorders among teaching staff of La Rioja, Spain. Clinical study: questionnaire, function vocal examination, acoustic analysis and videolaryngostroboscopy].

OBJECTIVE: To the analyse the risk factors of voice disorders among teaching staff of La Rioja, Spain. DESIGN: We carried out a transversal study of voice disorders in teaching staff of La Rioja (a random sample of 931 of 3.113 teachers). PATIENTS: 527 teachers of random sample took part of study: 332 female (63%) and 195 male (37%). METHODS: All teachers filled in a standard questionnaire and posteriorly they underwent an, ENT and functional vocal cord examination, videolaryngostroboscopy and acoustic analysis with MDVP. RESULTS: The prevalence of voice disorders among La Rioja Teachers was 57%: 20% for organic lesions, 8% for chronic laryngitis and 29% for functional disorders. Women compared with men did not have a higher prevalence of voice disorders (p > 0.05) (OR: 1.138). Professional and personal factors as well as classroom atmosphere were studied. The most relevant factors in the pathological group were previous vocal pathology, laryngeal surgery, gastroesophageal reflux and, classroom dryness and smoking habits. CONCLUSIONS: The most relevant factor of voice disorders in teaching professional is the vocal overwork during their job. It is advisable to carry out a clinical evaluation of all the future teachers in their educational programs.

Acoustics↗
PubMed2005

[Prevalence and incidence studies of voice disorders among teaching staff of La Rioja, Spain. Clinical study: questionnaire, function vocal examination, acoustic analysis and videolaryngostroboscopy].

OBJECTIVE: The aim of this study was calculate the prevalence and incidence of voice disorders among teaching staff of La Rioja, Spain. DESIGN: We carried out a transversal study of voice disorders in teaching staff of La Rioja (a random sample of 931 of 3113 teachers) and a longitudinal study (we collect the new cases during the 3 years which lasts the study). PATIENTS: 527 teachers of random sample took part of study: 332 female (63%) and 195 male (37%). METHODS: All of teachers fill in a standard questionnaire, ENT and function vocal examination, videolaryngostroboscopy and acoustic analysis with MDVP. RESULTS: The prevalence of voice disorders among La Rioja Teachers was 57%: 20.3% for organic lesions [nodular lesions (14%), polyps (2%), submucous suffusions (1.4%), edema Reinke (1.2%) Sulcus (0.4%), scalp (0.6%), leucoplasia (0.2%) vocal cord paralysis (0.2%)] 8.1% for chronic laryngitis [not specific (2.8%), smoke (3.9%) gastroe-sofageal reflux (2.5%)] and 29% for functional lesions [hyperfunctional dysphonia (7.5%) hypofunctional dysphonia (0.4%) vocal overefforts (18%) hyperplasia false cords (2.8)]. The incidence rate was 4 new cases each 1000 teachers and year. CONCLUSIONS: Organic lesions were more prevalent in women (25.4%) than in men (9.5%), but functional lesions and chronic laryngitis were more prevalent in men (36.5% and 13.2%) than in women (24% and 5%).

Acoustics↗
PubMed2005

Dendritic cell immunizations alone or combined with low doses of interleukin-2 induce specific immune responses in melanoma patients.

Dendritic cell (DC)-based therapy has proved to be effective in patients with a variety of malignancies. However, an optimal immunization protocol using DCs and the best means for delivering antigens has not yet been described. In this study, 20 patients with malignant melanoma in stages III or IV were vaccinated with autologous DCs pulsed with a melanoma cell lysate, alone (n = 13) or in combination with low doses of subcutaneous (s.c.) interleukin (IL)-2 injections (n = 7), to assess toxicity, immunological and clinical responses. Monocyte-derived DCs were morphological, phenotypic and functionally characterized in vitro. Peripheral blood mononuclear cells (PBMC), harvested from patients either prior to and after the treatment, were analysed using enzyme-linked immunosorbent spot (ELISPOT). After vaccination, 50% of the patients tested (seven of 13) from the first group and (three of seven) from the second, showed an increase in interferon (IFN)-gamma production in response to allogeneic melanoma cell lines but not to controls. Four of five tested human leucocyte antigen (HLA)-A2(+) patients with anti-melanoma activity also showed specific T cell responses against peptides derived from melanoma-associated antigens. Delayed type IV hypersensitivity reaction (DTH) against melanoma cell lysate was observed in six of 13 patients from the group treated with DC vaccines only and four of seven from the group treated with the combination of DCs and IL-2. Significant correlations were found between DTH-positive responses against tumour lysate and both disease stability and post-vaccination survival on the stage IV patients. There were no toxicities associated with the vaccines or evidence of autoimmunity including vitiligo. Furthermore, no significant enhancement was observed as a result of combining DC vaccination with IL-2. Our data suggest that autologous DCs pulsed with tumour lysate may provide a standardized and widely applicable source of melanoma specific antigens for clinical use. It is safe and causes no significant side effects and has been demonstrated to be partially efficient at triggering effective anti-melanoma immunity.

Antigen Presentation↗
PubMed2005

Anisakis simplex allergy: a murine model of anaphylaxis induced by parasitic proteins displays a mixed Th1/Th2 pattern.

The study of the singular hypersensitivity reactions to Anisakis simplex (A.s) proteins, may help us to undestand many of the unknown immune interactions between helmiths infections and allergy. We have developed a murine model of allergy to A. simplex, that mimics human A. simplex allergy to study the specific aspects of anaphylaxis induced by parasites. Male C3H/HeJ mice were intraperitoneally sensitized to A. simplex. Mice were then intravenous or orally challenged with A. simplex. Antigen-specific immunoglobulins, polyclonal IgE, anaphylactic symptoms, plasma histamine levels and cytokine profiles were determined. Comparative IgE immunoblot analyses were also performed. Specific IgE, IgG(1) and IgG(2a) were detected in sensitized mice since week 3. Polyclonal IgE raised and peaked with different kinetics. Intravenous A. simplex challenge produced anaphylaxis in mice, accompanied by plasma histamine release. Oral A. simplex challenge in similarly sensitized mice did not caused symptoms nor histamine release. Numerous A. simplex allergens were recognized by sensitized mouse sera, some of them similar to human serum. The A. simplex stimulated splenocytes released IL-10, IFN-gamma, IL-4, IL-13 and IL-5. We describe a new animal model of anaphylaxis. It exhibits characteristics of type I hypersensitivity reactions to Anisakis simplex similar to those observed in allergic humans. Different responses to i.v. or oral A. simplex challenges emerged, which did not reflect a window tolerization period. The cytokine profile developed (mixed Th(1)/Th(2) pattern) differed from the observed in classical models of anaphylaxis or allergy to food antigens. This model may permit to investigate the peculiar allergic reactions to parasitic proteins.

Allergens↗
PubMed2005

Clinical usefulness of total hepatitis C virus core antigen quantification to monitor the response to treatment with peginterferon alpha-2a plus ribavirin*.

SUMMARY: Early virological response may predict outcome following treatment with peginterferon alpha-2a and ribavirin in patients chronically infected with hepatitis C virus (HCV). As total HCV core antigen may constitute an alternative direct marker to HCV RNA for assessing the levels of viraemia in such patients, we evaluated the correlation between HCV core antigen and HCV RNA, and whether HCV core antigen at baseline, 4 and 12 weeks after treatment could predict sustained virological response (SVR) to combined therapy, in comparison with HCV RNA. A total of 290 serum samples from 58 previously treatment naïve chronic HCV patients were examined for HCV core antigen and HCV-RNA by means of quantitative HCV RNA when receiving combination therapy for the first time. SVR was significantly associated with basal HCV core antigen but not with HCV RNA. There was a good correlation between HCV core antigen and HCV RNA (r(2) = 0.781). The negative predictive value of HCV core antigen testing in predicting nonresponse at weeks 4 and 12 were 75 and 100%, and for undetectable or a 2-log drop in HCV RNA were 69.6 and 75% respectively. HCV core antigen detection is quick, and easy to perform alternative to HCV RNA, and could be used as a marker of HCV viraemia for monitoring the progress of therapy.

Antiviral Agents↗