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Biomedical subjects

M Rodríguez

Publications and source records attributed to M Rodríguez.

At least 55 records · Page 3Linked to original sources
PubMed2003

Neuronal activity in the substantia nigra in the anaesthetized rat has fractal characteristics. Evidence for firing-code patterns in the basal ganglia.

Current models of the basal ganglia assume a firing-rate code for information processing. We have applied five complementary computing methods to assess firing patterns in 188 cells of the substantia nigra in the anaesthetized rat. Fractal firing activity was found in 100% of nigral cells projecting to the superior colliculus, in 51% of cells projecting to the thalamus and in 33% of cells projecting to the pedunculopontine nucleus, but was practically absent in dopaminergic nigrostriatal neurons (3%). The finding of fractal firing patterns may lead to a better understanding of the normal operational mode and pathological manifestations of the basal ganglia.

Anesthesia↗
PubMed2003

Contribution of the ozonation pre-treatment to the biodegradation of aqueous solutions of 2,4-dichlorophenol.

The effect of ozonation on the biodegradability of 100-ppm aqueous solutions of 2,4-dichlorophenol has been investigated. BOD at 5, 10 and 21 days, BOD/COD and BOD/TOC ratios and the average oxidation state are presented. Biodegradability measured as BOD5/COD ratio was increased from 0 of the original solution to 0.25 at the moment of removing all the initial compound (corresponding to an ozone dose of 0.12 g L-1, 0.48 for BOD21/COD ratio). To test the effect of this pre-treatment, the biological oxidation of these pre-ozonated solutions was performed in two semi-continuous stirred tank reactors, one with non-acclimated sludge and one with acclimated-to-phenol sludge. The study showed that the TOC content of the pre-treated solution could be removed up to 68% by an aerobic biological treatment as well as co-digested with municipal wastewater (TOC removal up to 82%), with similar operating retention times to a municipal wastewater plant (12-24 h). Kinetic studies based on Monod model have also been carried out. Pseudo-first-order kinetic constants were found to be in the range of 0.5-0.8 L g TVSS-1 h-1.

Anthelmintics↗
PubMed2003

Validation and sensitivity analysis of a probabilistic model for dietary exposure assessment to pesticide residues with a Basque Country duplicate diet study.

The 'fitness for purpose' of a probabilistic model designed to assess dietary exposure to pesticides was validated. The model had to meet two prerequisites. First, it should provide more realistic estimates of intake than conservative methods. Second, it should not underestimate 'true' intakes. True intakes were estimated using a duplicate diet study. Three approaches were used to check the prerequisites: visual comparison, a statistical test of a high percentile, and a comparison for each infant of the duplicate diet, conservative and model intake values. Compliance with the prerequisites was met for the six pesticides selected, in the three approaches. Model outcome distributions reduced the uncertainty, considered as the difference between conservative and duplicate diet intakes, by 75-98% for high percentiles, depending on the pesticides. A sensitivity analysis of the model based on analysis of variance for selected factors was conducted for three pesticides. The factors included concentration and food consumption input data presentations, values assigned to pesticide-food commodities without analysis, values assigned to samples with results below the limit of reporting, unit-to-unit variability and processing factors. Their significance and relevance were studied. Assigning values to pesticide-food commodities without analysis and processing factors, when available, were the most relevant factors in this study.

Diet↗
PubMed2003

Localization of monoamine oxidase A and B and semicarbazide-sensitive amine oxidase in human peripheral tissues.

Monoamine oxidase (MAO) A and B and semicarbazide-sensitive amine oxidase (SSAO) localizations in peripheral human tissues were compared by immunohistochemistry. The primary antibodies used were mouse monoclonal anti-human MAO-A (6G11/E1) and anti-human MAO-B (3F12/G10/2E3) and a rabbit polyclonal anti-bovine SSAO antibody. Immunoreactivities of the samples, obtained from 6 routine autopsy cases, showed different distributions in the tissues studied (heart, lung, duodenum, liver, pancreas, spleen, thyroid gland, adrenal gland and kidney). The relative MAO-A, MAO-B and SSAO distributions indicated a widespread distribution of these enzymes in the human body that is characterized by a matching cellular pattern in only few tissues. These differences suggest that each amine oxidase may play a specific function in, at least some, peripheral tissues.

Journal Article↗
PubMed2003

Both duration and degree of hypercalcemia influence the reduced parathyroid hormone response to hypocalcemia after hypercalcemia.

The stimulation of parathyroid hormone (PTH) secretion by hypocalcemia is reduced when hypocalcemia is preceded by hypercalcemia. The present study investigates whether the duration and degree of hypercalcemia influence the reduced PTH response to hypocalcemia after hypercalcemia. In addition, the implication of the arachidonic acid (AA) signaling pathway in this effect is evaluated. The PTH response to hypocalcemia has been studied in a control group and in four groups of rabbits subjected to hypercalcemia for different periods of time (between 30 and 120 min) and at two levels of hypercalcemia (1 x 9 and 2 x 1 mM). AA levels have been measured in parathyroid glands from rabbits subjected to hyper- and hypocalcemia. When compared with controls, rabbits that had been hypercalcemic (2 x 1 mM) for 2 h showed a markedly attenuated PTH response to hypocalcemia (50% of normal PTHmax), rabbits that had been in hypercalcemia (2 x 1 mM) for 75 min had an intermediate PTH response to hypocalcemia (70% of normal PTHmax) and rabbits that had been subjected to either 30 min hypercalcemia of 2 x 1 mM or 120 min hypercalcemia of 1 x 9 mM had a normal PTH response to hypocalcemia. AA levels increased in hypercalcemia and decreased in hypocalcemia; however, no differences were observed at either calcium level in short-time (30 min) versus long-time (120 min) hypercalcemia. In conclusion, the attenuated PTH response to hypocalcemia after hypercalcemia is dependent on both the period of time that the parathyroid glands have been exposed to hypercalcemia and the degree of hypercalcemia. In addition, this reduced PTH response does not seem to be related to changes in the AA signaling pathway.

Animals↗
PubMed2003

[Perspectives in the treatment of allergy to latex: immunotherapy].

At present, allergy to latex is an important problem due to the severity of the symptomatology that it produces and the risk groups involved. Complete avoidance of latex is practically impossible, which is why in recent years there has been intense work on standardizing an extract in order not only to improve its clinical diagnosis but also to be able to offer a therapeutic alternative other than avoidance, such as immunotherapy. Since 1998, timely approaches to immunotherapy with latex have been published, with oral desensitization (three patients), subcutaneous (one patient) and sublingual (one patient). In every case there was an evident clinical improvement. At present, subcutaneous immunotherapy with latex, although efficient, is a high risk treatment. Sublingual immunotherapy with latex has recently been commercialized in Spain and we know of its efficacy through the results of an open test on 26 adult patients. The safety expectations are shown to be better than those for subcutaneous immunotherapy.

Humans↗
PubMed2003

[Inhalation techniques in the treatment of asthma].

In the pharmacological treatment of asthma, the most suitable way is by inhalation, since this enables us to achieve a greater concentration of medicine in the affected organ than systemic medication, and besides the latter's secondary effects are minimized. The suitable use of inhalers and hence their efficacy depends on very different factors. Some of those of a merely technical kind are as follows: A suitable volume of inhalation. The rhythm of inhalation. The length of the inspiratory apnea following administration of the medicine. The coordination between the inspiration of the aerosol and activation of the device, in the case of the metered dose inhaler (MDI). One of the reasons for the incorrect use of MDI aerosols is the lack of coordination between activation of the device and inspiration. This has led to the design of different devices that avoid the need for this coordination, such as: inhalation chambers and devices for inhaling dry dust. It has also been suggested in the literature that the causes of these mistakes are to be found in the health professionals not knowing, or not suitably teaching the patients how to handle the devices. In spite of being designed to facilitate correct administration, suitable knowledge of the technique of their use by the patient is required.

Administration, Inhalation↗
PubMed2002

Two cases of imported gnathostomiasis in Spanish women.

Reported here are two new cases of imported cutaneous gnathostomiasis that occurred in two Spanish women. The first patient acquired the helminth infection while travelling in Southeast Asia and the second in Mexico. Although the highest prevalence of gnathostomiasis infection is in Southeast Asia, the disease is now an emerging public health problem in some countries of Latin America. The cases reported here demonstrate the increasing frequency with which human gnathostomiasis is being diagnosed in nonendemic countries as a result of more extensive international travel and migration.

Adult↗
PubMed2002

Molecular cloning of verrucosidin-producing Penicillium polonicum genes by differential screening to obtain a DNA probe.

A differential molecular screening procedure was developed to obtain DNA clones enriched for verrucosidin-related genes that could be used as DNA probes to detect verrucosidin-producing Penicillium polonicum. Permissive and nonpermissive conditions for verrucosidin production were selected to obtain differentiated poly (A)+ RNA for the cloning strategy. P. polonicum yielded the highest amount of verrucosidin when cultured in malt extract broth at 25 degrees C without shaking. These conditions were selected as verrucosidin permissive conditions. When shaking was applied to the verrucosidin permissive conditions, verrucosidin was not detected. Approximately 5000 transformants were obtained for the library of DNA fragments from verrucosidin-producing P. polonicum and hybridized with cDNA probes obtained from poly (A)+ RNA of permissive and nonpermissive conditions. A total of 120 clones hybridized only with the permissive cDNA probes. From these, eight representative DNA inserts selected on the basis of size and labelled with fluorescein-dUTP were assayed as DNA probes in the second differential screening by Northern hybridization. Probe SVr1 gave a strong hybridization signal selectively with poly (A)+ RNAs from high verrucosidin production. When this probe was assayed by dot blot hybridization with DNA of different moulds species, hybridization was detected only with DNA from the verrucosidin-producing strain. The strategy used in this work has proved to be useful to detect unknown genes related to mycotoxins. In addition, the DNA probe obtained should be considered for the detection of verrucosidin-producing moulds.

Blotting, Northern↗
PubMed2002

Validation of the Spanish version of the geriatric depression scale (GDS) in primary care.

OBJECTIVE: To estimate the predictive value of the 30-question Geriatric Depression Scale (GDS) in Spanish and calculate the most adequate cut-point for its use in Primary Health Care consultations. METHOD: 218 patients over the age of 64 treated at three health centers of Area 10 in Madrid were selected. In the first phase, the subjects completed the GDS, the Mini-Mental State Examination (MMSE) and a questionnaire on health and socio-demographic variables. They were later interviewed using the Geriatric Mental Schedule (GMS), used as the gold standard by doctors who were unaware of the results of the GDS. Two categories were contemplated according to the results of the GMS: cases of depression (diagnosis of psychotic or neurotic depression) and non-psychiatric cases (no psychiatric diagnosis, although isolated symptoms could be present). RESULTS: 192 aged subjects were interviewed using the GDS and the GMS. Of these, 103 were considered "non-cases of depression" and 60 others made up the "cases of psychotic/neurotic depression" group. For the most effective cut-point (9/10), sensitivity was 86.7% and specificity 63.1%. Considering a prevalence of depression of 30%, the predictive value for positives was 50.2% and for negatives 91.7%. The Cronbach alpha coefficient was 0.82, and the area below the ROC curve obtained was 0.85. Those patients with cognitive deterioration had a mean GDS score similar to those that did not present deterioration (11.16 vs 10.52; p > 0.05). CONCLUSIONS: The Geriatric Depression Scale is valid as a screening test in Primary Care consultations due to its high sensitivity and negative predictive value. The most effective Spanish GDS cut-point (9/10) is lower than that obtained in the original English version (10/11).

Aged↗
PubMed2002

Response of GABAergic cells in the deep mesencephalic nucleus to dopaminergic cell degeneration: an electrophysiological and in situ hybridization study.

The deep mesencephalic nucleus (DMN) is a large midbrain reticular region located between the substantia nigra compacta and the superior colliculus. It contains GABAergic cells that share striatal afferents, thalamic and collicular efferents, as well as neurochemical and electrophysiological similarities, with those of the substantia nigra reticulata. In the present paper we used electrophysiological (firing rate and firing pattern) and morphological (densitometric analysis of in situ hybridization histochemical labeling for glutamic acid decarboxylase (GAD)65 and GAD67 mRNA) techniques, to study the response of DMN GABAergic cells to the degeneration of nigral dopaminergic cells. Our results showed that unilateral dopaminergic cell loss (after injection of 6-hydroxydopamine in the medial forebrain bundle) induces a bilateral and symmetrical increase in both firing rate and GAD67 mRNA levels and a decrease in GAD65 mRNA levels. These findings support the involvement of DMN GABAergic cells in the basal ganglia modifications that follow dopaminergic cell loss, also suggesting its participation in the pathophysiology of Parkinson's disease. The symmetry of effects, together with its recently reported bilateral projections to the thalamus and superior colliculus, suggest that unlike substantia nigra reticulata, DMN is involved in the interhemispheric regulation of basal ganglia, probably keeping their functional symmetry even after asymmetric lesions.

Animals↗
PubMed2002

Sarcoidosis in two patients with chronic hepatitis C treated with interferon, ribavirin and amantadine.

We report two patients with chronic hepatitis C, both nonresponders to a previous course of interferon (IFN), who developed or suffered an exacerbation of sarcoidosis while under treatment with IFN-alpha2a, ribavirin and amantadine. Patient 1: symptoms appeared after week 4 and treatment was withdrawn at month 9 due to severe weight loss, marked dyspnea, muscular weakness, dryness of mouth and facial paralysis. Stage III pulmonary sarcoidosis and polyneuropathy were confirmed. The patient had become steroid dependent and nine months after cessation of the treatment dyspnea and muscular weakness still persisted. She achieved a complete sustained response of hepatitis C. Patient 2: presented with a previous diagnosis of granulomatous hepatitis with chronic active hepatitis C and chronic dermatitis. The treatment exacerbated a cutaneous sarcoidosis. Furthermore, hiliar adenopathies consistent with stage I sarcoidosis became evident. Sarcoidosis responded to corticosteroids, but elevated transaminases and hepatitis C viraemia resisted. Hence, the combination of amantadine with ribavirin and IFN can develop or exacerbate subclinical sarcoidosis. A synergistic effect of these three drugs is suggested.

Adult↗