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Biomedical subjects

F Lorente

Publications and source records attributed to F Lorente.

At least 19 recordsLinked to original sources
PubMed2006

Promoter genetic variants of prostanoid DP receptor (PTGDR) gene in patients with asthma.

BACKGROUND: PTGDR gene has been identified as an asthma-susceptibility gene. Recently, functional genetic variants have been associated with asthma. The objective of this work was to study -549T>C, -441C>T and -197T>C PTGDR promoter polymorphisms in a Spanish population. METHODS: In this study, 197 Caucasian individuals were included. Asthma was specialist-physician diagnosed according to the American Thoracic Society (ATS) criteria and classified following the Global Initiative for Asthma (GINA) guidelines. Skin prick tests were performed in all patients. The polymorphisms were analyzed by direct sequencing. RESULTS: -197T>C polymorphism was significantly associated with asthma [Fisher's P-value = 0.007, Monte Carlo P-value (10(4) simulations) = 0.004]. Multivariate analysis adjusted for age and sex confirmed this association with an increased risk of asthma (OR, 3.06; 95% CI, 1.28-7.32; P-value = 0.012). CCT CCC diplotype was associated with asthma (P-value < 0.0001; OR, 1.15; 95% CI, 1.07-1.23), specifically with allergic asthma (P-value < 0.0001). CCT CCC diplotype is unambiguous. All individuals carrying this diplotype had asthma. CONCLUSION: We identified a specific promoter variant of PTGDR that could be associated with asthma. This diplotype is a combination of the two highest transcriptional efficiency haplotypes, recently described. Our in vivo results would support for the first time what was demonstrated in vitro about high-transcriptional efficiency PTGDR haplotypes in asthma.

Adult↗
PubMed2006

Analysis of 927T> C CYSLTRI and -444A > C LTC4S polymorphisms in patients with asthma.

BACKGROUND: The cysteinyl leukotrienes (cys-LTs) are proinflammatory mediators synthesized through the 5-lipoxygenase pathway of arachidonic acid metabolism. Cys-LTs exert their biological action by binding two types of G-protein-coupled seven transmembrane receptors, CYSLTR1 and CYSLTR2. The contribution of the cys-LT receptors to bronchial asthma has been established by the therapeutic efficacy of biosynthetic inhibitors and selective CYSLTR1 blockers. OBJECTIVE: The present study was designed to analyse two different polymorphisms 927T>C CYSLTR1 and -444A>C LTC4S, and to determine whether there is an association between these polymorphisms and the asthma phenotype in a Spanish population. METHODS: Both single nucleotide polymorphisms (SNPs) were analysed in 208 individuals (130 asthmatic subjects and 78 controls). A standardized history, physical examination, skin prick tests and lung function measurement were taken from all patients. Genotypes were determined by direct sequencing after polymerase chain reaction (PCR) amplification. RESULTS: In the group of male patients, the C allele of 927T> C CYSLTRI was more common among patients with asthma than controls. No association was detected between the -444A> C LTC4S polymorphism and the asthma phenotype. The combination of 927T CYSLTR1 and -444A LTC4S was less common in male patients with asthma than in controls (Fisher's P-value =.039; Monte Carlo P-value (after 104 simulations)= .045 and the combination of 927C CYSLTR1 and -444A LTC4S was slightly more frequent in patients with asthma. No differences were observed in the female group. CONCLUSIONS: The results suggest a certain trend of associations that could help to explain some controversial results in association studies of these genes from the leukotriene pathway, when considered individually. Further studies are needed to confirm such an association.

Adolescent↗
PubMed2001

Tick-bite-induced anaphylaxis in Spain.

Although there are very few reports of human anaphylaxis induced by tick bites, two such cases have recently been seen in Salamanca, Spain. To identify the tick species responsible, salivary-gland extracts from six species of hard tick and two of soft tick were prepared and used as allergens/antigens in skin-prick tests and serological analyses. For each case, the results of the skin tests were positive for several species of hard tick but negative for the soft ticks. ELISA and western blots revealed high titres of IgG against hard ticks (but not soft ticks) in the sera from both cases. However, serum from only one of the cases was found to be ELISA- and western-blot-positive for tick-specific IgE. Accordingly, the anaphylaxis seen in one case was IgE-mediated whereas that in the other case appeared to be IgE-independent. In both cases, most of the tick-specific antibodies only recognized carbohydrate epitopes. High levels of cross-reactivity between the salivary-gland extracts from several species of hard tick made it impossible to identify which species was responsible for each anaphylactic reaction, although the immunological results seem to point to Ixodes ricinus.

Anaphylaxis↗
PubMed1997

A critical analysis of total sialic acid and sialoglycoconjugate contents of bovine milk-based infant formulas.

BACKGROUND: Several infant formulas were bovine milk-based products. Mature bovine milk has a very low sialoglycoconjugate content compared with human milk from the first phases of lactation. METHODS: The present study was undertaken to determine total sialic acid and oligosaccharide, glycoprotein, and ganglioside sialic acid contents of bovine milk-based formulas. RESULTS: Starter formulas, designed for the first days/weeks after birth, have very similar sialic acid contents (233-266 mg/L fresh milk). We found more oligosaccharide-bound sialic acids (167-174 mg/L fresh milk) than those bound to proteins (53-84 mg/L fresh milk) in these formulas. The ganglioside sialic acid contents of starter formulas (952-1135 micrograms/L fresh milk) vary slightly from formula to formula. However, all the above-mentioned contents are lower than in human colostrum or transitional milk. CONCLUSIONS: Infants fed starter formulas have total sialic acid and oligosaccharide, glycoprotein, and ganglioside sialic acid intakes of 36, 28, 50, and 20%, respectively, of those fed human colostrum or transitional milk. By contrast, follow-on formulas, used from 4 to 5 months of age, provide total sialic acid and oligosaccharide, glycoprotein, and ganglioside sialic acid contents similar to those furnished by mature human milk. Since the reference standard for optimal nutrition in the early months of infancy is human milk, a supplementation with sialic acid-containing glycoconjugates of infant formulas recommended for the first days after delivery could be advisable when breast-feeding is not possible.

Animals↗
PubMed1993

Anti-Dirofilaria immitis IgE: seroepidemiology and seasonal variation in an exposed human population.

The seroprevalence of seasonal variation of human anti-Dirofilaria immitis IgE levels were studied in an area where specific IgM and IgG had been previously investigated. An antibody capture ELISA assay was used to detect specific IgE. The IgE seroprevalence observed in the whole population was 12.6%. No specific IgE was detected in atopic individuals or in sera from people suffering other helminthiases. The distribution of the IgE anti-D. immitis seroprevalence by age groups did not show differences. Females had significantly higher levels than males. This isotype of immunoglobulin peaks in July, decreasing sharply in October, and persisting at a level similar to that of a non exposed population during the rest of the year. No specific IgE were detected in subjects with pulmonary alterations related to the parasite, suggesting a possible relationship between the clinico-radiological status and the type of immunoglobulin synthesized in subjects infected by D. immitis.

Adult↗
PubMed1982

Inhibition of neutrophil migration by serum IgA from patients with IgA nephropathy.

Previously we showed that patients with IgA nephropathy present high serum levels of polymeric IgA and that in vitro polyclonal stimulation of their peripheral blood lymphocytes results in the synthesis of a large amount of true polymeric IgA. The aim of this study was to determine if the serum of patients with IgA nephropathy was capable of suppressing the directional migration of human normal polymorphonuclear cells (PMN), as do the polymeric fractions of IgA myeloma. Incubation of controls' PMN with fresh or heat-inactivated patients' plasma impaired the casein-induced directional migration significantly more than incubation with controls' plasma. This inhibitory effect was closely linked to polymeric IgA fractions and to a lesser extent with monomeric IgA immune complexes. The removal of IgA by immunoadsorption from patients' plasma completely abolished the migration suppression observed on controls' PMN. These results suggest that the high serum levels of polymeric IgA observed in patients with IgA nephropathy, by inhibiting directional migration and phagocytosis of PMN, and probably monocytes, could facilitate the persistent circulation and renal deposition of immune complexes.

Chemotaxis, Leukocyte↗
PubMed1981

Defective neutrophil mobility in the May-Hegglin anomaly.

A case of May-Hegglin anomaly is reported in which functional studies of PMN cells showed abnormalities consisting of impairment of chemotactic and chemokinetic responses, random mobility being otherwise normal. These abnormalities seem unrelated to microtubule system dysfunction or to abnormal cell deformability, since no defect was observed in the concanavalin A (Con A) surface receptors and no improvement of directional movement resulted when filters of larger pore size were used in the assays. Other possible mechanisms of the functional defect, such as abnormal membrane receptors to kinetic signals or metabolic abnormalities cannot be excluded. PMN function should be studied in additional cases in order to ascertain if these findings are a constant feature in the May-Hegglin anomaly, a syndrome in which undue susceptibility to infection has not been reported.

Adult↗
PubMed1980

Neutrophil chemotactic defect and hypogammaglobulinemia.

A 15-months-old boy developed agranulocytosis after administration of Chloramphenicol and Aminopyrine. In spite of total hematological recovery, the patient's immunological study disclosed a persistent neutrophil chemotactic defect and hypogammaglobulinemia. Other studies of specific and non-specific immunity were normal. Neutrophil adherence, random and random stimulated mobility were always within the normal range. The presence of chemotactic inhibitors was discarded. In vitro incubation of his neutrophils with Cytochalasin B at 0.1 micrograms/ml final concentration, reversed the chemotactic abnormality suggesting a possible cell membrane defect.

Agammaglobulinemia↗
PubMed1980

[Immunologic condition of the newborn (author's transl)].

Partial immaturity of the immunocompetent system is accounted for by the increased susceptibility to infections seen in human newborns. This immunodeficiency that includes specific and non-specific branches of immunity, affects both humoral and cellular components. Authors present a revision of the present knowledge, including their experience in this field.

B-Lymphocytes↗
PubMed1980

[Assessment of chemotactic activity in newborn infants and during the first year of life (author's transl)].

Chemotactic activity in 58 full term newborn and in infants during the first year of life was studied. Samples were taken from cord blood and blood drawn at three and 15 days after birth and at one, three, six and 12 month of age. Chemotactic activity was assessed by Boyden's technique. It was found that samples obtained before the first month of life had a decrease of function as compared with those of the mothers. Chemotactic indexes were parallel to those of mothers by the end of the first year of life. These findings suggest that impairment of the function observed in infants may be due to a deficit in synthesis of complement factors.

Adult↗
PubMed1980

[IgG and complement receptors in neutrophils from cord blood (author's transl)].

Percentage of cord blood polymorphonuclear leukocytes (PMN) bearing receptors for Fc portion of the IgG and for complement byproduct C3b are studied in 18 term newborns. Results are compared with those obtained in 20 healthy controls. Statistical analysis did not disclosed significative differences between both groups. Study was performed on total PMN population and not in a selected subpopulation as was done by previous authors.

Complement System Proteins↗
PubMed1980

[Development of the serum levels of complement during the first year of life].

Development of human C. system was studied by quantification of total serum hemolytical activity (CH50) and individual levels of C3, C4 and C5 in full term newborns. Comparison of results in newborn infants and their mothers sera is made. The ratios of neonatal-maternal sera concentrations were CH50, 0.29; C3, 0.61; C4, 0.51, and C5, 0.63. Serum concentrations of C3 and C4 reached maternal concentrations at twelve months of age. Serum concentrations of C4 and CH50 reached maternal levels at six months of age.

Age Factors↗