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N Rodríguez

Publications and source records attributed to N Rodríguez.

At least 19 recordsLinked to original sources
PubMed2005

Testing the hypothesis that system y(+)L accounts for high- and low-transport phenotypes in chicken erythrocytes using L-leucine as substrate.

Experiments were carried out to test the hypothesis that system y(+)L accounts for the high (HT) and low (LT) amino-acid transport phenotypes in chicken erythrocytes and to explain the different effect of selective breeding on lysine and leucine fluxes. L: -Leucine transport was characterized in individuals which had been separated into two groups (HT and LT) according to their capacity to transport L: -lysine across the erythrocyte membrane. Whereas lysine influx (1 muM: ) in the two groups differed by 32-fold (HT/LT), leucine influx was not significantly different. Average rates (nmol/ L cells/ min) were: 227 (HT) and 7.0 (LT) for L: -lysine, and 8.9 (HT) and 7.1 (LT) for L: -leucine. The differential ability of L: -lysine and L: -leucine fluxes to discriminate between the HT and LT phenotypes was shown to be consistent with the interactions of these substrates with system y(+)L and to vary depending on the conditions of the assay. It is shown that the two phenotypes can be clearly discriminated by measuring L: -leucine influx in the presence of Li(+). These results support the hypothesis that the HT and LT phenotypes reflect alterations in the function of system y(+)L and illustrate that the choice of the appropriate substrate and medium composition must be carefully considered when investigating the consequences of either experimental or natural alterations of broad-scope transporters.

Amino Acid Transport System y+L↗
PubMed2005

Internal iron biomineralization in Imperata cylindrica, a perennial grass: chemical composition, speciation and plant localization.

* The analysis of metal distribution in Imperata cylindrica, a perennial grass isolated from the banks of Tinto River (Iberian Pyritic Belt), an extreme acidic environment with high content in metals, has shown a remarkable accumulation of iron. This property has been used to study iron speciation and its distribution among different tissues and structures of the plant. * Mossbauer (MS) and X-ray diffraction (XRD) were used to determine the iron species, scanning electron microscopy (SEM) to locate iron biominerals among plant tissue structures, and energy-dispersive X-ray microanalysis (EDAX), X-ray fluorescence (TXRF) and inductively coupled plasma emission spectroscopy (ICP-MS) to confirm their elemental composition. * The MS spectral analysis indicated that iron accumulated in this plant mainly as jarosite and ferritin. The presence of jarosite was confirmed by XRD and the distribution of both minerals in structures of different tissues was ascertained by SEM-EDAX analysis. * The convergent results obtained by complementary techniques suggest a complex iron management system in I. cylindrica, probably as a consequence of the environmental conditions of its habitat.

Biological Transport, Active↗
PubMed2003

Direct and fast capillary zone electrophoretic method for the determination of Gleevec and its main metabolite in human urine.

A capillary zone electrophoretic (CZE) method was investigated for the determination of Gleevec and its main metabolite (N-demethylated piperazine derivative) in human urine using a fused-silica capillary (75 microm I.D.x60 cm total length, 10 cm effective length). The separation was performed with an hydrodynamic injection time of 10 s (0.5 p.s.i.) a voltage of -25 kV, a capillary temperature of 25 degrees C and a 100 mM phosphoric acid adjusted to pH 2 with the addition of triethanolamine. Under these conditions, the analysis takes about 5 min. A linear response over the 0.4-30.0 mg l(-1) concentration range was investigated for two compounds. A dilution of the sample was the only step necessary before the electrophoresis analysis. Detection limits of 0.1 mg l(-1) for Gleevec and its metabolite (S/N=3) were obtained. The developed method is easy, rapid and sensitive and has been applied to determine Gleevec and its main metabolite in clinical urine samples.

Antineoplastic Agents↗
PubMed2001

Disseminated infection and colonization by Scedosporium prolificans: a review of 18 cases, 1990-1999.

Scedosporium prolificans infection was analyzed in 18 patients from whom the fungus was isolated during the period 1990-1999. Of these 18 patients, 12 had some predisposing factor and either unconfirmed infection or colonization, and 6 patients had confirmed disseminated infection: 4 patients with leukemia died, 1 patient with breast cancer who underwent autologous bone marrow transplantation survived, and 1 patient with advanced acquired immunodeficiency syndrome died, although the fungal infection did not seem to affect his clinical symptoms.

Adult↗
PubMed2001

Phase I clinical evaluation of a neutralizing monoclonal antibody against epidermal growth factor receptor.

Ior egf/r3, a neutralizing monoclonal antibody (mAb) against Epidermal Growth Factor Receptor (EGFR) was generated at the Cuban Institute of Oncology. Immunoscintigraphic studies in 148 patients with this 99-m Technetium (99Tc) labeled mAb, showed a high sensitivity and specificity for in vivo detection of epithelial tumors. To study safety, pharmacokinetic and immunogenicity of ior egf/r3 at high doses, a phase I clinical trial was conducted. Nineteen patients with advanced epithelial tumors received 4 mAb intravenous infusions at 6 dose levels: from 50 to 500 mg. Previously, immunoscintigraphic images using the same mAb labeled with 99Tc were acquired. Blood samples were collected for pharmacokinetic analysis and HAMA response. After mAb therapy, objective response was classified according to WHO criteria. Ior egf/r3 was well tolerated in spite of the high-administered doses. Only a severe adverse reaction consisting of hypotension and lethargy was observed. In 13 patients, selective accumulation of 99Tc-labeled mAb was observed at the site of the primary tumor or the metastasis. Pharmacokinetic analysis revealed that elimination half-life and the area under the time-concentration curve increased linearly with dose. HAMA response was detected in 17 patients. After 6 months of mAb therapy, 4 patients had stable disease. One patient had a tumor partial remission after 3 cycles of ior egf/r3.

Adult↗
PubMed2001

Cutaneous leishmaniasis caused by members of Leishmania braziliensis complex in Nayarit, State of Mexico.

An epidemiological study was carried out in the northern Mexican state, Nayarit. Fourteen patients with possible cutaneous leishmaniasis skin lesions gave positive Montenegro skin tests. Biopsies were taken from the skin ulcer and analyzed by polymerase chain reaction (PCR) with specific primers for the Leishmania mexicana complex; however all biopsies were not amplified. PCR carried out with specific primers for the L. braziliensis complex resulted in the amplification of all patient DNA. DNA from 12 out of 14 biopsies gave positive amplification with primers species specific for L. (Viannia) braziliensis and hybridized with a species specific L. (V.) braziliensis probe. These results demonstrate the presence in Nayarit of at least two members of the L. braziliensis complex. Most of the cutaneous lesions were caused by L. (V.) braziliensis and two by another species belonging to the L. braziliensis complex. As far as we are aware, this is the first report of L. (V.) braziliensis in Nayarit. The main risk factor associated with the contraction of this disease in Nayarit is attributed to working on coffee plantations.

Animals↗
PubMed2001

HCV genotype analysis in HCV-HIV-co-infected Puerto Ricans who are injecting drug users: undetermined and mixed infections.

Direct percutaneous exposure is the main route of HCV transmission. In Puerto Rico half of people infected with HIV use illicit drugs. The effects of HCV in the course of HIV infection and vice versa have been extensively studied, but remain highly controversial. This may be due to HCV genetic heterogeneity. Therefore, a complex classification into genotypes has emerged that prompted us to determined how this impacts a population of intravenous drug users (IDUs) co-infected with HIV-1. Using Inno-LiPa II technique, we analyzed samples from 171 HCV-HIV-1-co-infected IDUs and 375 from a general HCV population of unknown HIV or source of infection status. Similar HCV genotype distribution was detected in these populations. HCV genotype 1a was the most frequently in IDUs-co-infected with HIV-1, followed by 1b and 3a. Twenty mixed infections and 5 undetermined genotypes were reported. A reduced HCV viral load was observed in HIV-1 positives with wasting syndrome. Individuals with a high HIV-1 viral load presented a low HCV viral load. There were no correlation between HCV genotypes and AIDS-related event. Patients with genotype 1b showed a higher HCV viral load. Males presented higher HCV viral load than females. Females were predominantly affected by genotype 1a, and men by 1a and 1b. Neither the HCV viral load nor the frequency of genotypes were influenced by the antiretroviral modality. The importance of continuous genotype monitoring is stressed.

Adult↗
PubMed2000

beta-catenin expression pattern in primary oesophageal squamous cell carcinoma. Relationship with clinicopathologic features and clinical outcome.

beta-Catenin has an essential role in intercellular adhesion and signal transduction. beta-catenin functions as a transcriptional activator downstream in the Wnt signalling pathway. Cytoplasmic stabilisation of beta-catenin, mainly due to inactivating mutations of the adenomatous polyposis coli (APC) tumour suppressor gene or activating mutations in exon 3 of the beta-catenin gene, can activate this important pathway in the development of several carcinomas. To determine whether this pathway for malignant transformation is important in oesophageal cancer, we analysed 39 primary oesophageal squamous cell carcinomas (OSCC). Immunohistochemical expression of beta-catenin was studied in formalin-fixed, paraffin-embedded tissue samples. Results were correlated with clinicopathological parameters and immunohistochemical expression of the proteins p53, E-cadherin, bcl-2 and Ki-67. All examined OSCC had beta-catenin expression localised in the cellular membrane, frequently with a heterogeneous pattern. Seven (18%) cases also showed immunoexpression in the cytoplasm and nuclei of the tumour cells. These seven tumours were localised in the upper (three) or in the middle third (four) of the oesophagus. Only one patient had p53 expression and all had bcl-2 expression. The consensus sequence for glycogen synthase kinase (GSK) 3beta phosphorylation in exon 3 of the beta-catenin gene was studied using polymerase chain reaction and direct sequencing in the seven cases with nuclear beta-catenin expression. No genetic alteration was found. These results suggest that beta-catenin expression may characterise a subset of OSCC.

Carcinoma, Squamous Cell↗
PubMed2000

Clinical trial with Secnidazole in a single dose in Venezuelan children infected by Giardia intestinalis.

The aim of this work was to evaluate in an open, noncomparative study the use of secnidazole in oral suspension given to Venezuelan children infected with Giardia intestinalis, from a community in Carapita, a slum area in Caracas. Seventy children from 2 to 11 years old (38 males and 32 females) were treated with a single oral dose of secnidazole (30 mg/Kg of body weight), after clinical and parasitological evaluation to make the diagnosis of active giardiasis. The effectiveness of treatment was determined by clinical examination and parasitological evaluation of feces samples 15 days after treatment. The results showed 95% of clinical cure with a significant decrease of the frequency of gastrointestinal symptoms. The parasitological cure was 98%, there were 4 failures at the end of treatment. Side effects observed after treatment were of mild intensity, lasting only few hours. These results show that a simple dose of secnidazole in an oral suspension is an effective, safe and well tolerated treatment for giardiasis in children and that this drug may be used as a mass treatment in risk populations.

Administration, Oral↗
PubMed1999

Autosomal dominant nocturnal frontal lobe epilepsy in a Spanish family with a Ser252Phe mutation in the CHRNA4 gene.

BACKGROUND: A large family with autosomal dominant nocturnal frontal lobe epilepsy from the south of Spain was studied. The clinical appearance of the disease in this family, which included 28 members, of whom 11 were affected and 2 were obligate carriers, was identical to that previously described in an Australian family and a Norwegian family, in which mutations in exon 5 of the CHRNA4 gene were found. METHODS: Following DNA extraction, the family was genotyped with 4 fluorescent markers flanking the locus to the CHRNA4 gene on chromosome 20q13.3, and lod score computations were performed. The exon 5 of the CHRNA4 gene was amplified between nucleotides 535 and 825 and polymerase chain reaction products were purified and sequenced directly. RESULTS: The same missense mutation as that found in the Australian family, C-->T, which causes the replacement of a serine with phenylalanine in amino acid 252 in exon 5, was detected. This mutation segregated with the disorder in all 11 affected members, in the 2 obligate carriers, and in 1 asymptomatic sibling, and was not found in 1 spouse and 1 daughter. Neither of the 2 polymorphisms found in a series of families with epilepsy were found in our sample [corrected]. CONCLUSIONS: These data confirm the clinical homogeneity in the phenotypic expression of autosomal dominant nocturnal frontal lobe epilepsy caused by mutation in the CHRNA4 gene, and the pathogenic role of the Ser252Phe mutation in this disorder.

Adult↗
PubMed1999

Specific prognostic factors for secondary pancreatic infection in severe acute pancreatitis.

BACKGROUND/AIMS: The aim of the present study was to investigate whether there are specific prognostic factors to predict the development of secondary pancreatic infection (SPI) in severe acute pancreatitis in order to perform a computed tomography-fine needle aspiration with bacteriological sampling at the right moment and confirm the diagnosis. METHODS: Twenty-five clinical and laboratory parameters were determined sequentially in 150 patients with severe acute pancreatitis (SAP) and univariate, and multivariate regression analyses were done looking for correlation with the development of SPI. RESULTS: Only APACHE II score and C-reactive protein levels were related to the development of SPI in the multivariate analysis. A regression equation was designed using these two parameters, and empiric cut-off points defined the subgroup of patients at high risk of developing secondary pancreatic infection. CONCLUSION: The results showed that it is possible to predict SPI during SAP allowing bacteriological confirmation and early treatment of this severe condition.

APACHE↗
PubMed1999

99mTc-labeled antihuman epidermal growth factor receptor antibody in patients with tumors of epithelial origin: Part III. Clinical trials safety and diagnostic efficacy.

UNLABELLED: Monoclonal antibody (moAb) ior egf/r3 is an IgG2a that recognizes the epidermal growth factor receptor (EGF-R). The aim of this study was to evaluate the diagnostic efficacy of the 99mTc-labeled moAb ior egf/r3 for the detection of epithelial-derived tumors, their metastases and recurrences. METHODS: One hundred forty-eight adult patients (51 women, 97 men; mean age 53 +/- 13 y) who were suspected of having cancer of epithelial origin were administered 3 mg/50 mCi (1.85 GBq) 99mTc-labeled moAb ior egf/r3 by intravenous bolus injection. Planar anterior and posterior images of the lesion sites and suspected metastases were acquired at 2, 4, 6 and 24 h after injection, and SPECT images were scanned at 5 h postinjection, using a 360 degrees circular orbit with 64 images. The backprojection method was used for image reconstruction with a Hamming-Hann filter. RESULTS: Labeling efficiency was always greater than 98.5% +/- 2.1 %. No adverse reactions or side effects were observed. Results of the biopsy specimens showed that 85.1% (126/148) of the patients had tumors of epithelial origin, 14.2% (21/148) were negative and 0.7% (1/148) had non-Hodgkin's lymphoma. The sensitivity rate by organ was as follows: brain (8/8, 100%), digestive tract (10/11, 90.9%), head and neck (17/23, 73.9%), lung (52/62, 83.9%) and breast (16/18, 88.9%). Overall sensitivity, specificity, accuracy, and positive and negative predictive values of the immunoscintigraphic imaging were 84.2% (106/126), 100.0% (22/22), 86.5% (128/148), 100% (106/106) and 52.4% (22/42), respectively. New metastases not identified previously by other diagnostic methods were detected in the 50% of the patients. CONCLUSION: Immunoscintigraphy with 99mTc-labeled moAb ior egf/r3 could be a useful procedure for the diagnosis and follow-up of the patients with tumors of epithelial origin.

Animals↗
PubMed1999

Haemoglobin concentrations and infection by Giardia intestinalis in children: effect of treatment with secnidazole.

The blood concentrations of haemoglobin were investigated in 82 children aged 2-9 years. Fifty-seven (31 boys and 26 girls) were stool-positive for Giardia intestinalis but the other 25, used as controls, were negative. The mean (S.D.) haemoglobin concentration among the infected children was significantly lower pre-treatment than that for the control group [11.6 (1.2) v. 12.6 (1.5) g/dl; P < 0.05]. Treatment of the infected children with a single oral dose of secnidazole (30 mg/kg) led to a significant increase in their mean haemoglobin level 15 days later, from 11.6 (1.2) g/dl pre-treatment to 12.4 (1.2) g/dl post-treatment (P < 0.05). The results indicate that the therapeutic control of giardiasis could be important in programmes to combat anaemia in children living in endemic areas.

Anemia↗
PubMed1998

Technetium-99m-labeled anti-EGF-receptor antibody in patients with tumor of epithelial origin: I. Biodistribution and dosimetry for radioimmunotherapy.

UNLABELLED: Accurate estimation of biodistribution and absorbed dose to normal organs and tumors is important for immunoscintigraphic studies and radioimmunotherapy treatment planning. METHODS: Four patients (3 men, 1 woman; mean age 54.8 +/- 9.2 yr; range 42-64 yr) were administered 3 mg of anti-human epidermal growth factor receptor (anti-hEGF-r) antibody (ior egf/r3), radiolabeled with 99mTc activity of 39.5 +/- 1.1 mCi (range 38.5 mCi-40.7 mCi) by intravenous bolus infusion. After administration, blood and urine samples were collected from three patients up to 24 hr after injection. Whole-body anterior and posterior scans were obtained at 5 min and 1, 3, 5 and 24 hr after injection. Using a computer program, regions of interest were drawn over the heart, liver, spleen, bladder and tumor to measure the activity in the source organs at each scanning time. Time-activity curves for each source organ were then fitted to monoexponential or biexponential functions by nonlinear least squares regression using the flexible polyhedrals method, which adequately fit our data with the correlation coefficient of 0.985 +/- 0.013, and were integrated to determine organ residence times. The mean absorbed doses to the whole body and various normal organs were then estimated from residence times and from blood and urine samples using the methods developed by the Medical Internal Radiation Dose Committee. The effective dose equivalent and effective dose were calculated as prescribed in ICRP Publication Nos. 30 and 60. RESULTS: Plasma disappearance curves of 99mTc-labeled anti-hEGF-r antibody were best-fit by a two-compartment model in all patients with a distribution half-life (t(1/2alpha)) of 0.207 hr +/- 0.059 hr (mean +/- s.d., n = 3) and an elimination half-life (t(1/2beta)) of 13.9 hr +/- 2.2 hr. Among the various organs, significant accumulation of the radiolabeled antibody was found in the liver (48.5% +/- 4.4%, mean +/- s.d.), heart (3.50% +/- 0.17%) and spleen (3.1% +/- 1.8%) at 5 min postadministration. These values were reduced to 3.2% +/- 0.4%, 0.1% +/- 0.01% and 0.1% +/- 0.1%, respectively, at 24 hr. Mean cumulative urinary excretion of 99mTc-labeled anti-hEGF-r antibody was 4.6% +/- 0.6% at 24 hr postinjection. Estimates of radiation absorbed dose to normal organs in rad/mCi administered (mean +/- s.d., n = 4) were: whole body 0.017 +/- 0.002; gallbladder wall 0.074 +/- 0.007; spleen 0.136 +/- 0.076; and liver 0.267 +/- 0.036. The effective dose equivalent and effective dose estimates for adults were 0.041 +/- 0.008 rem/mCi and 0.027 +/- 0.004 rem/mCi administered. CONCLUSION: This feasibility study indicates that 99mTc-labeled anti-hEGF-r antibody (ior egf/r3) can be used safely; this analysis provides a dosimetric framework for future studies. This monoclonal antibody, labeled with 188Re, could possibly permit a successful regional radioimmunotherapy of tumors of epithelial origin.

Adult↗