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Biomedical subjects

P López

Publications and source records attributed to P López.

At least 19 recordsLinked to original sources
PubMed2006

Enrichment of CD4+ CD25high T cell population in patients with systemic lupus erythematosus treated with glucocorticoids.

OBJECTIVES: To characterise and quantify the CD4+ CD25+ T cell population in patients with systemic lupus erythematosus (SLE) and to detect the possible influence of treatments and clinical manifestations. METHODS: Characterisation of CD25(low) and CD25(high) CD4+ T cells from healthy controls and from patients with SLE was carried out using flow cytometry, analysing the expression of activation and differentiation markers. The percentage of both circulating cell subsets was determined in 56 controls and 110 unselected patients with SLE. Data were related to treatment during the past 3 months and to various clinical manifestations. RESULTS: CD4+ CD25(high) lymphocytes from controls expressed low levels of CD69, CD154 or CD30, but also expressed glucocorticoid-induced tumour necrosis factor receptor, high levels of intracellular cytotoxin T lymphocyte-associated antigen 4, CD45RO and diminished amounts of CD4, all of which are phenotypic characteristics of natural regulatory T cells. CD4+ CD25(low) cells, on the other hand, expressed the highest levels of activation markers, indicating that they represent recently activated effector cells. Similarly, analysis of cells from patients with SLE showed the same two phenotypically distinguishable CD4+ CD25(low) and CD4+ CD25(high) populations, although both expressed slightly increased levels of activation markers. Quantitative analysis showed a considerably raised percentage of CD25(low) and, especially, CD25(high) cells in patients with SLE compared with controls. This increment was unrelated to clinical manifestations, but correlated with glucocorticoid treatment. Patients treated with glucocorticoids presented raised levels of CD25(high) cells, whereas untreated patients and those with anti-malarial or immunosuppressive drugs had levels similar to those in controls. CONCLUSIONS: The percentage of CD4+ CD25(high) cells was not altered in non-steroid-treated patients, whereas glucocorticoid treatment increased their frequency in patients with SLE.

Adult↗
PubMed2006

Determination of methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine and alprazolam in human plasma by liquid chromatography-electrospray ionization mass spectrometry.

A fast liquid chromatographic assay with mass spectrometric detection (LC/MS) has been developed and validated for the simultaneous determination of methadone (MT), its primary metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and alprazolam, in human plasma. The extraction procedure was performed with automatic solid phase extraction, and the compounds were separated with a Sunfire column using a gradient mode. Deuterated analogues for all of the analytes of interest were used for quantitation. Limits of detection (LOD) were established between 0.5 and 1 ng/ml. Linearity was obtained over a range of 2-2,000 ng/ml with an average correlation coefficient (R(2)) of >0.99. Intra- and inter-batch coefficients of variation and relative mean errors were less than 10% for all analytes and concentrations. The recoveries were higher than 50.0% in all cases. The method proved to be suitable for evaluation of plasma obtained from patients enrolled in a MT-maintenance program who are frequently treated with alprazolam as a sedative.

Alprazolam↗
PubMed2006

Tumorigenic activity of p21Waf1/Cip1 in thymic lymphoma.

The cell cycle inhibitor p21Waf1/Cip1 is among the most important mediators of the tumor suppressor p53. However, there is increasing evidence indicating that p21 could favor tumorigenesis in specific cell types. In particular, the absence of p21 delays the development of thymic lymphomas induced either by ataxia-telangiectasia mutated deficiency or by ionizing irradiation. Here, we extend these observations to the context of p53-deficient mice. The absence of p21 results in a significant extension of the lifespan of p53-null and p53-haploinsufficient mice, and this effect can be attributed exclusively to a decrease in the incidence of spontaneous thymic lymphomas. Specifically, despite the occurrence of a variety of tumor types in the context of p53 deficiency, the only tumors that were significantly impaired by the absence of p21 were thymic lymphomas. Moreover, the absence of p21 also delays the incidence of radiation-induced thymic lymphomas in p53-deficient mice. Interestingly, p21-deficient lymphomas have a higher apoptotic rate than p21-proficient lymphomas, and this could be on the basis of the delayed incidence of thymic lymphomas in the absence of p21. Together, our results indicate that p21 plays an oncogenic role restricted to thymic lymphomas that is mechanistically independent of p53 and associated to a lower tumor apoptotic rate.

Animals↗
PubMed2005

Solid- and vapor-phase antimicrobial activities of six essential oils: susceptibility of selected foodborne bacterial and fungal strains.

The antimicrobial activity of essential oils (EOs) of cinnamon (Cinnamon zeylanicum), clove (Syzygium aromaticum), basil (Ocimum basillicum), rosemary (Rosmarinus officinalis), dill (Anethum graveolens), and ginger (Zingiber officinalis) was evaluated over a range of concentrations in two types of contact tests (solid and vapor diffusion). The EOs were tested against an array of four Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus, Enterococcus faecalis, and Listeria monocytogenes), four Gram-negative bacteria (Escherichia coli, Yersinia enterocolitica, Salmonella choleraesuis, and Pseudomonas aeruginosa), and three fungi (a yeast, Candida albicans, and two molds, Penicillium islandicum and Aspergillus flavus). The rationale for this work was to test the possibility of creating a protective atmosphere by using natural compounds that could extend the shelf life of packaged foodstuffs while minimizing organoleptic alterations. In the solid diffusion tests, cinnamon and clove gave the strongest (and very similar) inhibition, followed by basil and rosemary, with dill and ginger giving the weakest inhibition. The fungi were the most sensitive microorganisms, followed by the Gram-positive bacterial strains. The Gram-negative strain P. aeruginosa was the least inhibited. The composition of the atmosphere generated by the EOs, and their minimum inhibitory concentrations (MICs), were determined using a disk volatilization method, in which no inhibition from rosemary or basil was observed. Cinnamon and clove, once again, gave similar results for every microorganism. As a general rule, MIC (fungi) << MIC (bacteria) with no clear differences between Gram-positive or -negative strains except for P. aeruginosa, which was not inhibited by any of the EOs in the vapor phase. The atmosphere generated from the EOs was analyzed by means of solid-phase microextraction combined with gas chromatography-ion trap mass spectrometry. Differences among the volatiles in the EOs, which may be responsible for the differences in their antimicrobial performances, were found.

Anethum graveolens↗
PubMed2005

Prevalence and intensity of haemogregarine blood parasites and their mite vectors in the common wall lizard, Podarcis muralis.

We describe the general field population biology of haemogregarines and mites in the wall lizard, Podarcis muralis, examining the factors that determine the prevalence and intensity of infection. The intensity of infection by haemogregarines in females was slightly lower in summer than in spring, whereas males maintained similar levels of intensity among all the seasons, probably due to immunosuppressive effects of testosterone. This is also supported because the prevalence and the infection intensity by mites were higher in males than in females. Parasite load was higher in lizards with better body condition, which could be reflecting the mortality of infected lizards with poor condition.

Animals↗
PubMed2005

Prevalence and intensity of blood and intestinal parasites in a field population of a Mediterranean lizard, Lacerta lepida.

We describe the blood and intestinal parasites in the Ocellated lizard, Lacerta lepida, examining the factors that determine the prevalence and intensity of infection of haemogregarines, and the prevalence of coccidia and nematodes. In relation to haemogregarines, no juveniles were detected as being infected, whereas 71.7 % of adults were infected. The prevalence of infection was positively related to the size of the adults. There were no differences between seasons or sexes in the prevalence or intensity of infection in adults. There were no significant differences in the prevalence of infection by nematodes between ages or sexes, nor in relation to the size of adult lizards, but adult lizards excreting coccidian oocysts tend to be smaller. During the mating period, reproductive activities lead to a decrease in the body condition. However, neither the intensity of haemogregarine's infection nor the prevalence of intestinal parasites was related to the lizards' body condition.

Animals↗
PubMed2005

Differential effect of IL10 and TNF{alpha} genotypes on determining susceptibility to discoid and systemic lupus erythematosus.

OBJECTIVE: To ascertain the possible involvement of functional interleukin 10 (IL10) and tumour necrosis alpha (TNFalpha) cytokine promoter polymorphisms on the susceptibility to discoid and systemic lupus erythematosus (DLE, SLE), and their associations with immunological features. METHODS: Single nucleotide polymorphisms of the IL10 (-1082, -819, and -592) and TNFalpha (-308) genes were determined using allele specific probes in 248 lupus patients and 343 matched controls. To assess functional significance of genotypes, basal mRNA cytokine levels were quantified in 106 genotyped healthy controls by real time RT-PCR. Specific autoantibodies and cutaneous manifestations were analysed in SLE patients and associated with functional genotypes. RESULTS: After analysing the distribution of IL10 and TNFalpha transcript levels according to promoter genotypes in healthy individuals, patients and controls were classified into functional single and combined genotypes according to the expected high or low constitutive cytokine production. High TNFalpha genotypes (-308AA or AG) were associated with SLE independently of IL10 alleles, whereas the risk of developing DLE and the prevalence of discoid lesion in SLE were higher in the high IL10/low TNFalpha producer group (-1082GG/-308GG). Cytokine interaction also influences the appearance of autoantibodies. Antibodies against Sm are prevalent among low producer patients for both cytokines, a genotype not associated with lupus incidence, whereas low IL10/high TNFalpha patients have the highest frequency of antibodies to SSa and SSb. CONCLUSIONS: IL10/TNFalpha interaction influences susceptibility to DLE and the appearance of specific autoantibodies in SLE patients, whereas high TNFalpha producer genotypes represent a significant risk factor for SLE.

Adult↗
PubMed2005

1,3-dihydroxy-5-(tridec-4',7'-dienyl)benzene: a new cytotoxic compound from Lithraea molleoides.

A dichloromethane extract from the leaves of Lithraea molleoides (Anacardiaceae), an argentine medicinal plant, showed cytotoxicity on human hepatocellular carcinoma cell line. Bioassay guided fractionation of this extract led to the isolation of a new active 5-alkyl resorcinol: 1,3-dihydroxy-5-(tridec-4',7'-dienyl)benzene. Chemical structure was established based on spectroscopic data (UV, IR, MS, 1H-NMR, 13C-NMR, COSY). This compound presented cytotoxic activity on 3 human tumoral cell lines: hepatocellular carcinoma cell line-Hep G2 (IC50 +/- SD of 68 +/- 2 microM), mucoepidermoid pulmonary carcinoma cell line-H292 (IC50 +/- SD of 63 +/- 5 microM) and mammary gland adenocarcinoma cell line -MCF7 (IC50 +/- SD of 147 +/- 5).

Anacardiaceae↗
PubMed2005

Efficacy of high loading doses of liposomal amphotericin B in the treatment of experimental invasive pulmonary aspergillosis.

This study aimed to investigate whether initial treatment of experimental pulmonary aspergillosis with high loading doses can be used as an alternative to standard therapeutic regimens. Steroid-immunosuppressed rats, infected intratracheally with Aspergillus fumigatus, received either amphotericin B deoxycholate (d-AmB) 1 mg/kg/day, liposomal amphotericin B (L-AmB) 5 mg/kg/day, or underwent a 3-day course of L-AmB 10 mg/kg, or 10 mg/kg for the first 3 or 4 days of treatment, followed by 3 mg/kg until the end of treatment. Therapy started 24 h after fungal challenge and lasted for 7 days. Compared to controls, survival was improved significantly in animals receiving any L-AmB regimen (p <or= 0.003), but not d-AmB. Compared with d-AmB, L-AmB at initial doses of 10 mg/kg followed by 3 mg/kg/day was consistently more effective, but only when measured in terms of survival, lung weight and glucosamine levels, and not log CFU. Despite the absence of significant differences between any of the L-AmB regimens, a trend towards better response rates with the higher loading dose was observed.

Amphotericin B↗
PubMed2005

[Laparoscopy in chronic abdominal pain in children].

UNLABELLED: The recurrent chronic abdominal pain (RAP) is one of the most usual pathologies in pediatrics. It may appear in the form of periodical or continuous sharp crisis. In order to be accepted as chronic, the presence of this pain must last at least 3 months. In many of the reference publications, only between 5 and 1% of the cases are considered to have an organic ethiology and the rest are labelled as functional processes of psychological origin. The reason for our communication is to show our experience on 304 RAP patients from 1995 to 2001. We also want to highlight the usefulness of laparoscopy in order to diagnose and treat 14.45% (44) of cases of this group of patients. MATERIAL AND METHODOLOGY: 304 patients between 5 and 14 years old were studied from 1995 to 2001. We followed a protocol of: medical and personal medical record, specific anamnesis for RAP, detailed description of the diet and intestinal habits, physical exploration. Laboratory: 1) blood analysis, hepatic profile, glucose, cholesterol, creatinine, amylase, 2) urine sediment and may be urine culture, 3) faeces analysis and 4) vaginal flow analysis. Image diagnosis is: simple abdomen radiography, ultrasonography and intestinal Rx. Guided and specific determinations: spired urea test, gastric chemism, lactose test, gastroscopy and biopsy, colonoscopy and biopsy, laparoscopy. RESULTS: In short, we can say: 74 patients (23.4%) come with inappropiate feeding diets, 31 (10.1%) with helicobacter pilori, 20 (6.5%) with adenoids, pharynx and pharyngeal processes, the same figure from gynaecologic origin, 18 (5.9%) from psychological origin, and in 44 cases (14.45%) laparoscopy was indicated. CONCLUSIONS: The anatomopathological study in the cases in which we carried out laparoscopic appendicectomy does not allow us to accept the symptoms of chronic appendicitis. The exploratory laparoscopy and the appendectomy have meant benefits for the solution to this pathology in 14.45% of patients. It is essential to carry out a long-term follow-up, at least 12 months, to be sure RAP is cured. We must carry on looking for aetiological cause of RAP.

Abdominal Pain↗
PubMed2004

Homologous and heterologous expression of RNase III from Lactococcus lactis.

The endoribonuclease III (RNase III), encoded by the rnc gene, is an important enzyme for RNA metabolism. In this report a chromosomal fragment containing the rnc gene from Lactococcus lactis was cloned and its expression was analyzed. Complementation assays performed in Escherichia coli demonstrate that the lactococcal RNase III (Lac-RNase III) is able to process rRNAs and to regulate the levels of polynucleotide phosphorylase (PNPase). These results demonstrate that the lactococcal enzyme is able to substitute the Ec-RNase III not only in the rRNA processing, but also in the processing of mRNAs. The amount of lactococcal rnc transcript in an E. coli Deltarnc strain was 3.3-fold higher than in the wild type strain, suggesting that the E. coli RNase III triggers the degradation of the heterologous rnc mRNA. Lac-RNase III is able to cleave an in vitro synthesized mRNA substrate specific for the Bacillus subtilis homolog. Using this substrate, we standardized an enzymatic assay which allows the specific detection of the endonucleolytic activity of Lac-RNase III in L. lactis and E. coli crude extracts.

Amino Acid Sequence↗
PubMed2004

Prevalence and intensity of haemogregarinid blood parasites in a population of the Iberian rock lizard, Lacerta monticola.

The study of the effect of parasites on their host populations is essential for understanding their role in host population dynamics and ecology. We describe the general field population biology of haemogregarines in the Iberian rock lizard, Lacerta monticola, examining the factors that determine the prevalence and intensity of infection. Prevalence and infection intensity were higher in adults than in juvenile lizards. The prevalence rate was higher in larger lizards, probably because they were also older and had been more often in contact with parasites during their lifetime. During the mating season, the intensity of parasite infection was greater in males than in females, probably due to immunosuppressive effects of testosterone. The parasite load had a negative effect on the body condition during the reproductive season. The results suggest that the interactions between parasites and hosts are not stable in this lizard population.

Animals↗
PubMed2004

Development of an inducible system to control and easily monitor gene expression in Lactococcus lactis.

This report describes the implementation and use of a maltose-inducible system for regulated gene expression in Lactococcus lactis. The system was established using Green Fluorescent Protein as reporter. The transcription of a gene of interest from the inducible promoter of pLS1RGFP plasmid vector can be easily monitored by fluorescence spectroscopy and microscopy. As an example, the lactococcal ribonuclease III was overproduced in an active form.

Blotting, Western↗
PubMed2003

Beneficial effects of HLA class II incompatibility in living donor liver transplantation.

OBJECTIVE: To analyze the impact of HLA matching in both patient and graft evolution after LDLT. MATERIAL AND METHODS: Twenty recipients underwent LDLT with follow-up of 3 to 30 months. HLA typing was performed on all donor-recipient pairs; class I antigens were typed using serological methods and class II loci (DRB1 and DQB1) using low-resolution molecular typing. Recipient sera were cross-matched with donor lymphocytes. Antigen mismatches were analyzed for each locus individually, for each class as a whole and for HLA class I immunogenic triplets according to HLA Matchmaker software. RESULTS: Eighteen of 20 donor-recipient pairs were HLA haploidentical. All but one of the recipients had a negative cross-match before transplantation. While there was not a statistically significant correlation between HLA class I mismatches and the incidence of acute rejection episodes, HLA class II matching in DRB1 and DQB1 loci appeared to be associated with a higher incidence of acute rejection episodes after LDLT. Both host-versus-graft (HvG) and graft-versus-host (GvH) HLA class II compatibilities correlated with rejection episodes, especially for the GvH direction. CONCLUSIONS: HLA class II matching for DRB1 and DQB1 loci appears to be associated with a higher incidence of acute rejection episodes after LDLT. In this study, mismatches in class I HLA antigens are not related to an higher incidence of acute rejection episodes nor other complications after LDLT. Further studies are needed to unveil the role of HLA matching in LDLT.

Adolescent↗
PubMed2003

Liver transplantation for hilar cholangiocarcinoma: Spanish experience.

INTRODUCTION: Palliative treatment for nondisseminated irresectable hilar cholangiocarcinoma (HCC) carries a 0% 5-year survival rate. The role of orthotopic liver transplantation (OLT) in these patients is controversial because the survival rate is lower than that for other indications for transplantation and the lack of available donor organs. The aim of this paper was to review the Spanish experience in OLT for HCC and identify prognostic factors for survival. METHODS: We retrospectively reviewed 36 patients undergoing OLT for HCC over 13 years. RESULTS: The actuarial survival rate at 1, 3, and 5 years was 82%, 53%, and 30%, respectively. The main cause of death was tumor recurrence (53%). In the univariate analysis, the factors for a poor prognosis were vascular invasion (P<.001) namely 0% survival at 3 years when present versus 63% and 35% at 3 and 5 years, respectively, when it was not; and stages III to IVA (P<.05), namely 15% survival at 5 years versus 47% for stages I to II. Lymph node and perineural invasion also reduce survival. In the multivariate analysis, the factors for poor prognosis included vascular invasion (P<.01) and stages III to IVA (P<.01). CONCLUSION: OLT for nondisseminated irresectable HCC has higher survival rates at 3 and 5 years than palliative treatments, especially with initial stage tumors, which means that more information is needed to better select cholangiocarcinoma patients for transplantation.

Bile Duct Neoplasms↗
PubMed2003

Liver transplantation for peripheral cholangiocarcinoma: Spanish experience.

INTRODUCTION: Palliative treatment for nondisseminated unresectable peripheral cholangiocarcinoma (PCC) carries a 0% 5-year survival rate. The role of orthotopic liver transplantation (OLT) in these patients is controversial because the survival rate is lower than with other indications for transplantation and the lack of available donor organs. The aim of this paper was to review the Spanish experience in OLT for PCC to identify prognostic factors for survival. METHODS: We retrospectively reviewed 23 patients undergoing OLT in Spain for PCC over a period of 13 years. RESULTS: The actuarial survival rates were 77%, 65%, and 42% at 1, 3, and 5 years, respectively. The main cause of death was tumor recurrence (35%). Prognotic factors for an adverse outcome were pTNM classification (P<.05) in the univariate analysis and perineural invasion (P<.05) and stages III or IVA (P<.05) in the multivariate analysis. CONCLUSIONS: OLT for nondisseminated irresectable PCC displays higher survival rates at 3 and 5 years than palliative treatments, especially for tumors in the initial stages, which means that more information is needed to help better select PCC patients for transplantation.

Bile Duct Neoplasms↗
PubMed2003

Epidemiology of systemic lupus erythematosus in a northern Spanish population: gender and age influence on immunological features.

The present work was planned to research epidemiological and immunological features of systemic lupus erythematosus (SLE) in a Caucasian population from the north of Spain (Asturias). There is only one specialized immunology laboratory in this region where samples from all patients with a plausible or a firm diagnosis of SLE are referred for immunological analysis. Since 1992 we have reviewed registered data from samples submitted to the immunology laboratory with a firm, definitive diagnosis of SLE, based on the fulfillment of the American College of Rheumatology (ACR) criteria. We have constructed a database, which included 367 SLE patients. The point prevalence was 34.12/ 100 000 (95% CI: 30.63-37.61/100 000), whereas the incidence rate calculated during the last five years was 2.15/100 000/year (95% CI: 1.76-2.54/100 000/year). The female/male ratio varied according to the age at diagnosis, being maximum (50 : 1) between 22 and 28 years. The median age at diagnosis was significantly lower in females than in males. Immunological features also yielded sex and age peculiarities. The percentage of patients with anti-SSa antibodies yielded significant differences between males (18.6%) and females (34.6%). Anti-RNP and anti-Sm antibodies were more frequently present in childhood-onset patients, the difference with the oldest-onset group being statistically significant. Other analyses did not show significant differences, although, as a whole, we observed a trend towards a higher presence of autoantibodies related to an early disease onset.

Adolescent↗