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Biomedical subjects

I Rodriguez

Publications and source records attributed to I Rodriguez.

At least 19 recordsLinked to original sources
PubMed2006

Faceting and commensurability in crystal structures of colloidal thin films.

This Letter investigates the influence of finite size effects on the particle arrangement of thin film colloidal crystals. A rich variety of crystallographic faceting with large single domain microcrystallites is shown. Optical reflectance experiments together with scanning electron microscopy permit the identification of the crystal symmetry and the facet orientation, as well as the exact number of monolayers. When the cell thickness is not commensurable with a high symmetry layering, particles arrange themselves in a periodic distribution of (111)- and (100)-orientated face centered cubic (fcc) microcrystallites separated by planar defects. These structures can be described as a fcc ordering orientated along a vicinal surface, modified by a periodic distribution of fcc (111) stacking faults.

Colloids↗
PubMed2006

The global atmospheric environment for the next generation.

Air quality, ecosystem exposure to nitrogen deposition, and climate change are intimately coupled problems: we assess changes in the global atmospheric environment between 2000 and 2030 using 26 state-of-the-art global atmospheric chemistry models and three different emissions scenarios. The first (CLE) scenario reflects implementation of current air quality legislation around the world, while the second (MFR) represents a more optimistic case in which all currently feasible technologies are applied to achieve maximum emission reductions. We contrast these scenarios with the more pessimistic IPCC SRES A2 scenario. Ensemble simulations for the year 2000 are consistent among models and show a reasonable agreement with surface ozone, wet deposition, and NO2 satellite observations. Large parts of the world are currently exposed to high ozone concentrations and high deposition of nitrogen to ecosystems. By 2030, global surface ozone is calculated to increase globally by 1.5 +/- 1.2 ppb (CLE) and 4.3 +/- 2.2 ppb (A2), using the ensemble mean model results and associated +/-1 sigma standard deviations. Only the progressive MFR scenario will reduce ozone, by -2.3 +/- 1.1 ppb. Climate change is expected to modify surface ozone by -0.8 +/- 0.6 ppb, with larger decreases over sea than over land. Radiative forcing by ozone increases by 63 +/- 15 and 155 +/- 37 mW m(-2) for CLE and A2, respectively, and decreases by -45 +/- 15 mW m(-2) for MFR. We compute that at present 10.1% of the global natural terrestrial ecosystems are exposed to nitrogen deposition above a critical load of 1 g N m(-2) yr(-1). These percentages increase by 2030 to 15.8% (CLE), 10.5% (MFR), and 25% (A2). This study shows the importance of enforcing current worldwide air quality legislation and the major benefits of going further. Nonattainment of these air quality policy objectives, such as expressed by the SRES-A2 scenario, would further degrade the global atmospheric environment.

Air Pollutants↗
PubMed2006

Oxacillin-resistant and multidrug-resistant Staphylococcus aureus in Lima, Peru.

In a hospital in Lima, Peru, a review of 103 Staphylococcus aureus infections was conducted during 2002. The prevalence of oxacillin-resistant S. aureus strains was 68%; 25% of strains were resistant to multiple drugs. Previous use of antibiotics and undergoing a surgical procedure during the current hospital stay were associated with the presence of an oxacillin-resistant S. aureus strain.

Adult↗
PubMed2006

Treatment of hirudin overdosage in a dialysis patient with heparin-induced thrombocytopenia with mixed hemodialysis and hemofiltration treatment.

We report a patient who developed type II heparin-induced thrombocytopenia (HIT) and accidentally received a recombinant hirudin (r-hirudin) overdosage. Treatment with hemodialysis (HD) using high-flux polysulfone dialyzer and hemofiltration was performed. Length of treatment was adjusted, monitoring activated partial thromboplastin time (aPTT) to 1.5-2.5 times the mean of the normal range. She developed deep venous thrombosis and occlusion of vascular access. Only after cessation of heparin lock catheter, platelet count began to increase. After one year of treatment with acenocoumarol and additional low-dose r-hirudin, neither bleeding nor thrombotic episodes have been reported.

Aged↗
PubMed2005

Optimization of solid-phase microextraction conditions for the determination of triclosan and possible related compounds in water samples.

A solid-phase microextraction (SPME) method for the determination of triclosan, methyl triclosan, 2,4-dichlorophenol and 2,3,4-trichlorophenol (considered as possible triclosan metabolites) in water samples was optimised. Analytes were first concentrated on a SPME fibre, directly exposed to the sample, and then triclosan and the two chlorinated phenols on-fibre silylated using N-methyl-N-(tert.-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA). Methyl triclosan remained unaffected during the derivatization step. Compounds were determined using gas chromatography in combination with mass spectrometry (GC-MS). Influence of different factors on the efficiency of extraction and derivatization steps was systematically investigated. Using a polyacrylate (PA) fibre quantification limits below 10 ng/l, and acceptable relative standard deviations, were obtained for all compounds after an extraction time of 30 min. On-fibre silylation was carried out in only 10 min. Moreover, the efficiency of the procedure was scarcely affected by the type of water sample. The method was applied to several samples of treated and raw wastewater, triclosan was found in all samples, at concentrations from 120 to 14,000 ng/l, and 2,4-dichlorophenol in most of them, at levels up to 2222 ng/l.

Acetamides↗
PubMed2005

Behaviour of pharmaceuticals and personal care products in a sewage treatment plant of northwest Spain.

Thirteen pharmaceutical and cosmetic compounds have been surveyed along the different units of a municipal sewage treatment plant (STP) to study their fate across each step and the overall removal efficiency. The STP studied corresponds to a population of approximately 100,000 inhabitants located in Galicia (northwest Spain), including three main sections: pre-treatment (coarse and fine screening, grit and fat removal); primary treatment (sedimentation tanks); and secondary treatment (conventional activated sludge). Among all the substances considered (galaxolide, tonalide, carbamazepine, diazepam, diclofenac, ibuprofen, naproxen, estrone, estradiol, ethinylestradiol, roxitromycin, sulfamethoxazole and iopromide), only significant concentrations were found for two musks (galaxolide and tonalide), two antiphlogistics (ibuprofen and naproxen), two natural estrogens (estrone, estradiol), one antibiotic (sulfamethoxazole) and the X-ray contrast media (iopromide), being the other compounds below the quantification level. In the primary treatment, only the fragrances were partly removed, with efficiencies of 20-50% for galaxolide and tonalide. However, the aerobic treatment caused an important reduction in all compounds detected, between 35 and 75%, with the exception of iopromide. The overall removal efficiency of the STP ranged between 70 and 90% for the fragrances, 45 and 70% for the acidic compounds, around 67% for estradiol and 57% for the antibiotic sulfamethoxazole.

Adsorption↗
PubMed2004

Activation of phospholipase C-gamma1 in human keratinocytes by hyperosmolar shock without enzyme phosphorylation.

Human keratinocytes are exposed to strong physical changes, and have the potentiality to react to external stimuli by switching on adaptation mechanisms. In hyperosmotically shocked keratinocytes a rapid and strong increase in calcium has been observed. We showed that this increase could not be prevented by growing the cells in medium devoid of calcium and in the presence of EGTA, indicating that the intracellular calcium increase was due to delivery from internal stores. Further, we observed an increased synthesis of dyacylglycerol and inositol trisphosphates after shock, suggesting that phospholipase C mediates both events. Our experiments demonstrated that osmotic shock in human keratinocytes leads to activation of phospholipase C-gamma1, as measured using an in vitro assay system. This activation is independent of protein tyrosine phosphorylation and corresponded to a relocation of the enzyme to perinuclear membranes as shown by immunofluorescence.

Arachidonic Acid↗
PubMed2003

Determination of chloramphenicol residues in shrimps by liquid chromatography-mass spectrometry.

A liquid chromatographic method with mass spectrometric detection and identification (LC-MS) is presented for the determination of chloramphenicol (CAP) in shrimp tissues. Homogenized shrimp samples were extracted with phosphate buffer (pH 7.0). Clean-up was carried out on a C(18) SPE cartridge. Chloramphenicol was determined by LC-MS-ESI in negative mode. The column used was a Symmetry Shield with a mixture of acetonitrile-water (25:75) as mobile phase. Shrimp samples were fortified at CAP levels between 0.2 and 50 ng g(-1) with 5D-CAP as internal standard. At these levels, accuracies lay between 101 and 110% and between-day reproducibilities were lower than 7.1%, expressed as the variation coefficient of the mean. Limit of decision (CCalpha) was 0.02 ng g(-1). Limit of quantitation (LOQ) was 0.2 ng g(-1).

Animals↗
PubMed2003

Comparison of phenotypic and genotypic markers for characterization of an outbreak of Salmonella serotype Havana in captive raptors.

AIMS: To establish a typing method for tracing the epidemic relationship of 16 strains of Salmonella serotype Havana isolated from captive raptors showing no symptomatology and residing in a wildlife hospital in Spain. METHODS AND RESULTS: Antimicrobial susceptibility testing, ribotyping, pulsed field gel electrophoresis (PFGE) and amplified fragment length polymorphism (AFLP) methodology were applied. Ten unrelated strains of serotype Havana were included as a control group to provide a basis of for the efficiency of the different markers used. All outbreak-related strains were resistant to nalidixic acid and streptomycin and showed the same ripotype, pulsotype and AFLP pattern. CONCLUSIONS: This is the first time that AFLP analysis has been tested with serotype Havana isolates and it has demonstrated to be the most useful epidemiological tool for discriminating between unrelated and outbreak-related strains of this serotype. The results obtained suggest that all the Salmonella serotype Havana isolates represented a common outbreak strain whose origin of contamination could not be established although it is thought that it was the poultry meat used for raptors'diet. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study suggests the importance of microbiological analysis of these products in order to prevent contamination and dissemination of Salmonellae in this kind of Hospital.

Animals↗
PubMed2002

Quantitative analysis of the novel depsipeptide anticancer drug Kahalalide F in human plasma by high-performance liquid chromatography under basic conditions coupled to electrospray ionization tandem mass spectrometry.

Kahalalide F (KF) is a novel cyclic depsipeptide anticancer drug, which has shown anticancer activity both in vitro and in vivo especially against human prostate cancer cell lines. To characterize the pharmacokinetics of KF during a phase I clinical trial in patients with androgen refractory prostate cancer, a method was developed and validated for the quantitative analysis of KF in human plasma using high-performance liquid chromatography (HPLC) coupled to positive electrospray ionization tandem mass spectrometry (ESI-MS/MS). Microbore reversed-phase liquid chromatography (LC) performed with mobile phases containing trifluoroacetic acid, an additive commonly used for separating peptides, resulted in substantial suppression of the signal for KF on ESI-MS/MS. An alternative approach employing a basic mobile phase provided an excellent response for KF when detected in the positive ion mode. Plasma samples were prepared for LC MS/MS by solid-phase extraction on C(18) cartridges. The LC separation was performed on a Zorbax Extend C(18) column (150 x 2.1 mm i.d., particle size 5 micro m) with acetonitrile -10 mM aqueous ammonia (85 : 15, v/v) as the mobile phase, at a flow-rate of 0.20 ml min(-1). A butyric acid analogue of KF was used as the internal standard. The lower limit of quantitation (LLQ) using a 500 micro l sample volume was 1 ng ml(-1) and the linear dynamic range extended to 1000 ng ml(-1). The inter-assay accuracy of the assay was -15.1% at the LLQ and between -2.68 and -9.05% for quality control solutions ranging in concentration from 2.24 to 715 ng ml(-1). The inter-assay precision was 9.91% or better at these concentrations. The analyte was stable in plasma under all relevant conditions evaluated and for a period of 16 h after reconstituting plasma extracts for LC analysis at ambient temperature.

Antineoplastic Agents↗
PubMed2002

The serine protease Omi/HtrA2 is released from mitochondria during apoptosis. Omi interacts with caspase-inhibitor XIAP and induces enhanced caspase activity.

Proteome analysis of supernatant of isolated mitochondria exposed to recombinant tBid, a proapoptotic Bcl-2 member, revealed the presence of the serine protease Omi, also called HtrA2. This release was prevented in mitochondria derived from Bcl-2-transgenic mice. Release of Omi under apoptotic conditions was confirmed in vivo in livers from mice injected with agonistic anti-Fas antibodies and was prevented in livers from Bcl-2 transgenic mice. Omi release also occurs in apoptotic dying but not in necrotic dying fibrosarcoma L929 cells, treated with anti-Fas antibodies and TNF, respectively. The amino acid sequence reveals the presence of an XIAP interaction motif at the N-terminus of mature Omi. We demonstrate an interaction between endogeneous Omi and recombinant XIAP. Furthermore we show that endogenous Omi is involved in enhanced activation of caspases in cytosolic extracts.

Amino Acid Sequence↗
PubMed2001

Differentiation of embryonic stem cell lines generated from adult somatic cells by nuclear transfer.

Embryonic stem (ES) cells are fully pluripotent in that they can differentiate into all cell types, including gametes. We have derived 35 ES cell lines via nuclear transfer (ntES cell lines) from adult mouse somatic cells of inbred, hybrid, and mutant strains. ntES cells contributed to an extensive variety of cell types, including dopaminergic and serotonergic neurons in vitro and germ cells in vivo. Cloning by transfer of ntES cell nuclei could result in normal development of fertile adults. These studies demonstrate the full pluripotency of ntES cells.

Animals↗
PubMed2001

Drug-induced QT prolongation in women during the menstrual cycle.

CONTEXT: Women have a higher incidence of torsades de pointes than men, but it is not known if the risk of drug-induced torsades de pointes varies during the menstrual cycle. OBJECTIVES: To determine if the degree of QT prolongation in response to ibutilide varies with the menstrual cycle phase and to compare QT prolongation between women and men. DESIGN AND SETTING: Cohort study of men and women who received the same intervention conducted between November 1998 and November 2000 at a general clinical research center of a university hospital. PARTICIPANTS: A volunteer sample of 58 healthy adults (38 men and 20 women) aged 21 to 40 years. INTERVENTION: A low dose of ibutilide (0.003 mg/kg), infused intravenously for 10 minutes. Subjects were monitored for 120 minutes. Women received the intervention on 3 separate occasions to correspond with menstrual cycle phases, which were verified by using hormonal assays. MAIN OUTCOME MEASURE: QT interval, recorded from electrocardiogram at timed intervals during and after ibutilide infusion and standardized for variations in heart rate (QTc). RESULTS: Maximum (mean [SD]) millisecond increase in QTc after ibutilide infusion was greater for women during menses (63 [13]) and the ovulatory phase (59 [17]) compared with women during the luteal phase (53 [14]) and compared with men (46 [16]; P =.002 vs menses and P =.007 vs ovulation). Progesterone (r = -0.40) and progesterone-to-estradiol ratio (r = -0.41), but not estradiol (r = 0.14) or testosterone (r = 0.09), were inversely correlated with ibutilide-induced QT prolongation. CONCLUSIONS: Menstrual cycle and sex differences exist in QTc responses to ibutilide, with the greatest increase in QTc corresponding to the first half of the menstrual cycle.

Adult↗
PubMed2001

Functional annotation of a full-length mouse cDNA collection.

The RIKEN Mouse Gene Encyclopaedia Project, a systematic approach to determining the full coding potential of the mouse genome, involves collection and sequencing of full-length complementary DNAs and physical mapping of the corresponding genes to the mouse genome. We organized an international functional annotation meeting (FANTOM) to annotate the first 21,076 cDNAs to be analysed in this project. Here we describe the first RIKEN clone collection, which is one of the largest described for any organism. Analysis of these cDNAs extends known gene families and identifies new ones.

Animals↗
PubMed2001

Cartilage and bone biological markers in the synovial fluid of osteoarthritic patients after hyaluronan injections in the knee.

OBJECTIVE: To evaluate synovial fluid levels of cartilage and bone biological markers after repetitive intra-articular injections of sodium hyaluronate (HA) in knee osteoarthritis (OA) patients. METHODS: Twenty patients with knee OA were evaluated before and after 5 weekly injections of HA. To study cartilage and bone biological markers, synovial fluid and urine samples were collected simultaneously with the first (FI=week 0) and before the last injection (LI=week 4) of HA. Not commercially available markers (cartilage oligomeric matrix protein (COMP), proteoglycan monomers and cyanogen bromide peptide 11 of the type II collagen chains (alpha (II) CA11B)) were determined by an indirect inhibition ELISA developed and standardized in our laboratory. RESULTS: We found a significant reduction in levels of proteoglycan monomers (30+/-16 vs. 22+/-10 microg/ml, p<0.05), an increase in COMP concentration (2.9+/-0.9 vs. 3.6+/-0.9 microg/ml, p<0.05) and osteocalcin (BGP) levels (8.7+/-8 vs. 11.9+/-9 ng/ml, p<0.05). No significant changes were observed in the levels of alpha (II)CB11B), metalloproteinase-1 (MMP-1) or pyridinium cross-link/creatinine (Pyr/Cr). CONCLUSIONS: HA could elicit an indirect response on the cartilage and bone metabolism due to the increased overuse of the joint caused by the analgesic effect of HA. However, a direct HA action on the metabolism of chondrocytes must not be ruled out.

Aged↗
PubMed2001

Endonuclease G: a mitochondrial protein released in apoptosis and involved in caspase-independent DNA degradation.

A hallmark of apoptosis is the fragmentation of nuclear DNA. Although this activity involves the caspase-3-dependent DNAse CAD (caspase-activated DNAse), evidence exists that DNA fragmentation can occur independently of caspase activity. Here we report on the ability of truncated Bid (tBid) to induce the release of a DNAse activity from mitochondria. This DNAse activity was identified by mass spectrometry as endonuclease G, an abundant 30 kDa protein released from mitochondria under apoptotic conditions. No tBid-induced endonuclease G release could be observed in mitochondria from Bcl-2-transgenic mice. The in vivo occurrence of endonuclease G release from mitochondria during apoptosis was confirmed in the liver from mice injected with agonistic anti-Fas antibody and is completely prevented in Bcl-2 transgenic mice. These data indicate that endonuclease G may be involved in CAD-independent DNA fragmentation during cell death pathways in which truncated Bid is generated.

Animals↗
PubMed2001

Contribution of haemoglobin and membrane constituents modification to human erythrocyte damage promoted by peroxyl radicals of different charge and hydrophobicity.

We have investigated the influence of the free radical initiator characteristics on red blood cell lipid peroxidation, membrane protein modification, and haemoglobin oxidation. 2,2'-Azobis(2-amidinopropane) (AAPH) and 4,4'-azobis(4-cyanovaleric acid) (ACV) were employed as free radical sources. Both azo-compounds are water-soluble, although ACV presents a lowed hydrophilicity, evaluated from octanol/water partition constants. At physiological pH, they are a di-cation and a di-anion, respectively. AAPH and ACV readily oxidise purified oxyhemoglobin in a very efficient free radical-mediated process, particularly for ACV-derived radicals, where nearly one heme moiety was modified per radical introduced into the system, suggesting that negatively charged radicals react preferentially at the heme group. The radicals derived from both azo-compounds lead to different oxidation products. Methemoglobin, hemichromes and choleglobin were produced in AAPH-promoted hemoglobin oxidation, while ACV-derived radicals predominantly form hemichromes, with very low production of choleglobin. Red cell damage was evaluated at the level of hemoglobin and membrane constituents modification, and was expressed in terms of free radical doses. Before the onset of the lytic process, ACV leads to more lipid peroxidation than AAPH, and induces a moderate oxidation of intracellular Hb. This intracellular oxidation is markedly increased if ACV hydrophilicity is decreased by lowering the pH. On the other hand, AAPH-derived radicals are considerable more efficient in promoting protein band 3 modification and cell lysis, without significant intracellular hemoglobin oxidation. These results show that the lytic process is not triggered by lipid peroxidation or hemichrome formation, and suggest that membrane protein modification is the relevant factor leading to red blood cell lysis.

Amidines↗