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Biomedical subjects

O Palacios

Publications and source records attributed to O Palacios.

At least 19 recordsLinked to original sources
PubMed2005

Priority organic pollutant assessment of sludges for agricultural purposes.

A comprehensive characterization of five of the seven priority organic pollutants listed in the draft of the "Working document on sludge" [EU, 2000. Working Document on Sludge 3rd Draft. Unpublished, 19 p] has been carried out during 2001-2003 in sludge samples from Catalonia (NE Spain). One hundred and thirty-nine samples belonging to 20 Waste Water Treatment Plants (WWTPs), seven sludge treatment (thermal drying) and three composting sludge plants were taken in order to determine the concentration of polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs), di-2-(ethyl-hexyl)-phthalate (DEHP), nonylphenol and nonylphenol ethoxylates with one or two ethoxy groups (NPE), polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). PCDD/F concentrations were in general lower than the 100 ng I-TEQ/kg limit suggested in the above-mentioned document. In the same way, 98.5% for PCBs, 97% for PAH and 92.8% for DEHP of the samples presented concentrations lower than 0.8 mg/kg dm, 6 mg/kg dm and 100 mg/kg dm, respectively. In contrast, the vast majority of samples contained NPE concentrations much higher than 50mg/kg dm limit. The values ranged from 14.3 to 3150 mg/kg dm (median value=286.6 mg/kg) being composted sludge samples the less contaminated ones (17.9-363.4 mg/kg dm; median value=89.3 mg/kg). Special attention should be paid to the Catalan sludge NPE contamination owing to the high levels detected.

Agriculture↗
PubMed2003

MTO: the second member of a Drosophila dual copper-thionein system.

Drosophila MTO metal binding features were analyzed for comparison with MTN, the paralogous Drosophila metallothionein, and to classify MTO as either zinc- or copper-thionein. This was achieved by a combination of in vivo, in vitro and in silico methodologies. All the results unambiguously classified MTO as a second Drosophila copper-thionein, putting Drosophila forward as the only metazoan in which any zinc-thionein has still to be reported. Interestingly, experimental data only showed minor differences in the coordinative behavior of both MTs, but provided a characteristic spectroscopic fingerprint, revealing the possible binding of chloride anions in certain metal-MTO aggregates.

Amino Acid Sequence↗
PubMed2003

Determination of neutron absorbed doses in lithium aluminates.

Lithium-based ceramics have been proposed as tritium breeders for fusion reactors. The lithium aluminate (gamma phase) seems to be thermally and structurally stable, the damages produced by neutron irradiation depend on the absorbed dose. A method based on the measurement of neutron activation of foils through neutron capture has been developed to obtain the neutron absorbed dose in lithium aluminates irradiated in the thermal column facility and in the fixed irradiation system of a Triga Mark III Nuclear Reactor.

Journal Article↗
PubMed2000

Metallothionein-III prevents glutamate and nitric oxide neurotoxicity in primary cultures of cerebellar neurons.

Metallothionein (MT)-III, a member of the MT family of metal-binding proteins, is mainly expressed in the CNS and is abundant in glutamatergic neurons. Results in genetically altered mice indicate that MT-III may play neuroprotective roles in the brain, but the mechanisms through which this protein functions have not been elucidated. The aim of this work was to assess whether MT-III is able to prevent glutamate neurotoxicity and to identify the step of the neurotoxic process interfered with by MT-III. Glutamate neurotoxicity in cerebellar neurons in culture is mediated by excessive activation of glutamate receptors, increased intracellular calcium, and increased nitric oxide. It is shown that MT-III prevented glutamate- and nitric oxide-induced neurotoxicity in a dose-dependent manner, with nearly complete protection at 0.3-1 microgram/ml. MT-III did not prevent the glutamate-induced rise of intracellular calcium level but reduced significantly the nitric oxide-induced formation of cyclic GMP. Circular dichroism analysis revealed that nitric oxide triggers the release of the metals coordinated to the cysteine residues of MT-III, indicative of the S(Cys)-nitrosylation of the protein. Therefore, the present results indicate that MT-III can quench pathological levels of nitric oxide, thus preventing glutamate and nitric oxide neurotoxicity.

Animals↗
PubMed1998

[Resistance of human immunodeficiency virus (HIV) to zidovudine. Genotypic analysis in strains isolated from Chilean patients].

BACKGROUND: Resistance of HIV to AZT is the result of mutations in the pol gene that codifies the enzyme reverse transcriptase. AIM: To assess the resistance to antiretroviral drugs in Chilean patients infected with HIV. MATERIAL AND METHODS: The presence of mutations was searched in 22 patients infected with HIV. The emergence or persistence of these mutations was studied in sequential samples of 19 patients. The presence of the mutation that confers resistance to didanosine (DDI) was studied in those subjects exposed to the drug. Polymerase chain reaction techniques were used to analyze mutations in codons 41, 70 and 215 of the pol gene (resistance to AZT) and the mutation in codon 71 (resistance to DDI). RESULTS: On admission, none of the patients without previous exposure to AZT had drug resistance mutations. Seven of 12 patients (58.3%) that had received AZT had mutations in codon 215. In two, they were associated to a mutation in codon 41 and in two, a mutation in codon 70. After a mean follow up of 14 months, 13 of 15 patients (86%) that received AZT had viral strains genotypically resistant to the drug. In nine of these, the resistance was associated with disease progression. None of the 10 patients that received DDI had the mutation in codon 74 that confers resistance to the drug. However, in one of these patients, that never received AZT, a virus with a mutation in codon 215 was detected. CONCLUSIONS: A high percentage of patients that have received monotherapy with AZT have genotypic resistance to the drug. This resistance is associated with clinical and immunological derangement in 70% of these subjects.

Anti-HIV Agents↗
PubMed1996

[Neuroborreliosis in Chile. Report of a child probably infected by imported pets].

Lyme disease, caused by the spirochete Borrelia burgdorferi, has several clinical manifestations and is transmitted to man by tick bites. In Chile and Latin America, several cases have been reported, but none with immunoblot confirmation or isolation of the infecting organism. We report a 9 year old boy consulting with bilateral facial palsy, polyradiculoneuritis with tetraparesis and meningeal irritation. Cerebrospinal fluid analysis showed increased protein concentration without pleocytosis and negative viral or bacterial cultures. IgM antibodies against Borrelia burgdorferi, were positive by ELISA and were confirmed by immunoblot at the Reference Laboratory of the University of Connecticut. The child had a recent contact with hamsters brought from Germany. The substantiation of Lyme disease existence in Chile should prompt the search and isolation of the causal agent.

Animals↗
PubMed1995

[Isolation of Coxsackieviruses B5 in a fatal case of meningoencephalitis].

A nine months old boy was admitted to the hospital with the diagnosis of meningoencephalitis 15 days after having a clinically diagnosed chickenpox. Lumbar puncture showed clear CSF with 0.23 g/l of proteins, 57 mg/dl of glucose, 30 red cells/mm3 and 5 leukocytes/mm3. Blood count showed a packed red cell volume of 22%, a hemoglobin of 7 g/dl, 14800 leukocytes with 1% eosinophils, 5% band and 39% segmented neutrophils, 50% lymphocytes and 5% monocytes and a decreased platelet count. On the fourth hospitalization day, the patient had vomiting, irritability and stiff neck. A new lumbar puncture showed a clear CSF that differed from the former only in the glucose level that increased to 102 mg/dl. The patient died and the necropsy showed a congestive and enlarged brain and congestive meninges infiltrated with lymphocytes. There was lymphoid follicle hyperplasia in the small bowel and enlarged mesenteric lymph nodes. Samples of brain, brain stem, spinal cord and stools were sent for virological study. A Coxsackie B-5 virus was isolated from the spinal cord sample.

Brain↗
PubMed1981

Hereditary alterations in tumor-host relationship.

An indirect exposure of mice during their fetal stage of development to Ehrlich ascites tumor cells alters the animals' response to this tumor during their adult life. Control mice injected intraperitoneally with Ehrlich tumor cells react in various ways to the presence of this alien tissue. The response is especially evident during the first 48-72 h post-injection. Several aspects of this complex reaction are absent in those animals which were exposed to this tumor in utero. The measurably altered reactivity toward the Ehrlich tumor cells is hereditary. Possible mechanisms of this alteration are discussed.

Acridine Orange↗
PubMed1978

[Intestinal amebiasis in children II. Evaluation of various diagnostic technics and different therapeutic regimens].

The diagnostic usefulness of different laboratory tests was evaluated in 20 cases of invasive intestinal amebiasis: the direct coproparasitoscopic exam in mucus obtained by rectoscopy was positive in 90.0 per cent of cases; the same exam done in mucus obtained by the spoon technique was positive in 40.0 per cent. The serum antibodies investigated by the counterimmunoelectrophoresis technique were found in 40.0 per cent of the cases in the first blood sample obtained at the hospital admisssion, and 15 days later this percentage increased to 66.6 percent. The fecal antigen studied by the ELISA technique was positive in 70.0 per cent of the cases. Simultaneously, the therapeutic effectiveness of emetine and metronidazol was evaluated, and with both therapeutic programs total recovery was obtained in 100.0 per cent of the cases; there were no significative differences in the symptoms duration after the start of therapy, and side effects were not observed. The results must be considered preliminary, because the calculated full sample has not been concluded.

Adolescent↗