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Biomedical subjects

A Rodríguez

Publications and source records attributed to A Rodríguez.

At least 127 records · Page 7Linked to original sources
PubMed1999

Initial effects of the toxic waste spill (Aznalcóllar mine accident) on the aquatic macrofauna of the Guadalquivir Estuary.

The initial effects of the toxic waste spill in April 1998 at the Aznalcóllar mine (SW Spain) on the nektonic community of the Guadalquivir Estuary were examined at three sampling sites using univariate and multivariate techniques. Since studied communities showed a considerable seasonal trend, only seasonally homogenous periods were compared to analyse effects of the spill: May-August 1997 (before spill) and May-August 1998 (after spill). Results of both techniques (two-way nested ANOVA and ANOSIM tests, P > 0.05) indicated that there was no significant difference between the nektonic community of the estuary before and after the spill (monthly number of species, abundance, biomass and similarity among samples). Conversely, an unusually high density was observed at the outer sampling site immediately after the spill for species typical of more stagnant estuarine habitats. This feature seems to indicate that the fauna in the estuarine area through which the untreated water penetrated into the main course may have been disturbed. Results also suggest that this initial sudden input of fresh water to the estuary could have enhanced the effects of an increased river flow (a drop in the salinity). Nevertheless, longer temporal series of data, especially for permanent estuarine inhabitants, are recommended before conclusions can be drawn on the effects of the toxic waste spill on estuarine communities.

Accidents, Occupational↗
PubMed1999

Hippocampal theta waves as an electrocardiogram rhythm timer in paradoxical sleep.

Episodes of heart arrhythmia are present during paradoxical sleep, a known non-homeostatic--'open loop'--physiological state, while wakefulness and slow wave sleep exhibit 'closed-loop' control. A brain-stem autonomic oscillator, a hypothalamic and a corticofrontal center, entrained by baroreceptor input, has been proposed as the main heart rhythm control system. We are postulating another neural timer, i.e. the hippocampal theta rhythm. Cross-correlation between the R-wave of the electrocardiogram and the hippocampal theta revealed phase-locking during behavioral periods under 'open-loop' operations as paradoxical sleep indicative of a participation of such a rhythm in autonomic heart rate timing, in coordination with hypothalamic neuronal activities.

Animals↗
PubMed1999

cAMP regulates Ca2+-dependent exocytosis of lysosomes and lysosome-mediated cell invasion by trypanosomes.

Ca2+-regulated exocytosis, previously believed to be restricted to specialized cells, was recently recognized as a ubiquitous process. In mammalian fibroblasts and epithelial cells, exocytic vesicles mobilized by Ca2+ were identified as lysosomes. Here we show that elevation in intracellular cAMP potentiates Ca2+-dependent exocytosis of lysosomes in normal rat kidney fibroblasts. The process can be modulated by the heterotrimeric G proteins Gs and Gi, consistent with activation or inhibition of adenylyl cyclase. Normal rat kidney cell stimulation with isoproterenol, a beta-adrenergic agonist that activates adenylyl cyclase, enhances Ca2+-dependent lysosome exocytosis and cell invasion by Trypanosoma cruzi, a process that involves parasite-induced [Ca2+]i transients and fusion of host cell lysosomes with the plasma membrane. Similarly to what is observed for T. cruzi invasion, the actin cytoskeleton acts as a barrier for Ca2+-induced lysosomal exocytosis. In addition, infective stages of T. cruzi trigger elevation in host cell cAMP levels, whereas no effect is observed with noninfective forms of the parasite. These findings demonstrate that cAMP regulates lysosomal exocytosis triggered by Ca2+ and a parasite/host cell interaction known to involve Ca2+-dependent lysosomal fusion.

1-Methyl-3-isobutylxanthine↗
PubMed1999

Distribution of keratins, vimentin, and actin in the testis of two South American camelids: vicuna (Vicugna vicugna) and llama (Lama glama). An immunohistochemical study.

The purpose of the present study was to investigate the pattern of distribution of cytokeratins, vimentin and muscular actin in the testis of vicuna (Vicugna vicugna) and llama (Lama glama) two species of camelids native of the Andean high plateau of South America. Testicular biopsies of four vicunas and five llamas were used. Animals were healthy breeders. The tissues were processed by standard immunohistochemistry with antipancytokeratinAE1/AE3, antikeratin 18 (K 18), CAM 5.2 (antikeratin 5, 18, and 19), antivimentin, and smooth-muscle-specific antiactin antibodies to track the cytoskeletal pattern of testicular cells. Using AE1/AE3 antibody the immunostaining was found in the epithelial lining of tubuli recti and rete testis. The reaction was relatively stronger in the apical cytoplasm of epithelial cells. The testicular cells of the two species showed no reaction to K 18 and CAM 5.2 antibodies. Antivimentin antibody stained the basal cytoplasm of the Sertoli cells, the Leydig cells, and the epithelial lining of tubuli recti and rete testis. In the last two structures the immunostain was relatively more intense in the basal cytoplasm of epithelial cells. Antiactin antibody stained the peritubular cells and the muscle cells of the lamina propria oftubuli recti and rete testis. The presence in these species of only some keratins found in man, its coexpression with vimentin in epithelial lining of tubuli recti and rete testis and the peritubule organization, so different from other ungulates may reflect a differential adaptation of the cytoskeleton to particular reproductive strategies.

Actins↗
PubMed1999

Uptake, Distribution, and Metabolism of 1-Naphthaleneacetic Acid and Indole-3-Acetic Acid During Callus Initiation From Actinidia deliciosa Tissues.

1-Naphthaleneacetic acid (NAA) and 6-benzyladenine (BA) were required for in vitro callus formation at the basal edge of kiwifruit (Actinidia deliciosa [A. Chev] Liang and Ferguson, cv. Hayward) petioles. The uptake, metabolism, and concentration of NAA and indole-3-acetic acid (IAA) content were examined in the explants during the callus initiation period. After 1, 6, 12, 24, 48, and 96 h of culture in the presence of [H(3)]NAA, petioles were divided into apical, middle, and basal portions and analyzed. Except for a high IAA level measured at 12 h, IAA content decreased in tissues during a culture period of 96 h. NAA uptake was higher in petiolar edges than in the middle portion, and NAA was rapidly conjugated with sugars and aspartic acid inside the tissues. The amide conjugation was triggered in apical and basal portions from 12 h and in the middle part from 48 h, with alpha-naphthylacetylaspartic acid being the major metabolite. Free-NAA concentration in cultured petioles achieved an equilibrium with the exogenously applied NAA (0.27 µm) from 12 h, and it remained constant thereafter. The relationships between the role attributed to NAA and BA in the initiation and the maintenance of disorganized growth of callus in kiwifruit cultures are discussed.

Journal Article↗
PubMed1999

Atraumatic spontaneous posterior subluxation of the sternoclavicular joint.

We report a case of atraumatic spontaneous posterior subluxation of the sternoclavicular joint in a 19-year-old woman without any known underlying pathology. There was no history of injury. The patient was treated operatively using the gracilis tendon to reinforce the anterior sternoclavicular ligament. One year later the patient is asymptomatic and has returned to her usual life.

Adult↗
PubMed1999

Efficacy and safety of photodynamic therapy versus Nd-YAG laser resection in NSCLC with airway obstruction.

A prospective controlled randomized trial was performed in order to assess the effectiveness and safety of photodynamic therapy versus laser resection in 31 patients with partial or complete tracheobronchial obstruction due to inoperable non-small cell lung cancer. Fourteen patients received dihaematoporphyrin ether and argon dye laser photoradiation, and 17 patients received Nd-YAG laser resection. Endoluminal obstruction of >75% was found in 77.4% of the patients. Among the symptoms, cough was more severe in the Nd-YAG group (p=0.02). Patients in both groups experienced symptomatic relief after treatment (p=0.003). Patients in the photodynamic therapy (PDT) group showed a significantly longer time until treatment failure (p=0.03) and longer median survival (p=0.007). Bronchitis and photosensitization (both in the PDT group) were the most common adverse effects. There was one death, probably related to treatment, in the PDT group. Photodynamic therapy and neodymium-yttrium aluminium garnet laser resection showed similar effectiveness and safety in the palliation of symptoms. The more prolonged survival in the photodynamic therapy group may have been due to differences in tumour stage between the groups. The degree of obstruction improved after treatment in both groups. In conclusion, photodynamic therapy is a valid method of palliation in partially or totally obstructing non-small cell lung carcinoma.

Aged↗
PubMed1999

Intraurethral stent prosthesis in spinal cord injured patients with sphincter dyssynergia.

This study is an analysis of the Memotherm prosthesis in spinal cord injured patients with Detrusor-external sphincter dyssynergia (DESD). Twenty-four patients were evaluated urodynamically before and after placement of the intraurethral stent prosthesis. All the patients had been chronically managed with an indwelling urinary catheter, intermittent catheterization or condom catheters. Sixty-six per cent had history of recurrent urinary tract infection, 37% had symptoms of autonomic dysreflexia. Nine patients had previous external sphincterotomy. Follow-up ranged from 3 39 months (mean 15.4 months). After stent insertion all patients were able to achieve spontaneous reflex voiding with the use of condom catheter. Postoperative urodynamics parameters bladder leak point pressure and residual urine volume decreased significantly after stent insertion. Stent insertion was accomplished without any operative complications. In four patients stent migration (16%) required telescoping a new system over the migrated stent. In two patients the stent was removed because of problems of infection and calculus formation. In conclusion, this system (Memotherm) is an attractive, and potentially reversible treatment for DESD in SCI patients.

Electromyography↗
PubMed1999

Stable expression of the Lactobacillus casei bacteriophage A2 repressor blocks phage propagation during milk fermentation.

A general strategy was applied to implement resistance against temperate bacteriophages that infect food fermentation starters through cloning and expression of the phage repressor. Lactobacillus casei ATCC 393 and phage A2 were used to demonstrate its feasibility as milk fermentation is drastically inhibited when the strain is infected by this phage. The engineered strain Lact. casei EM40::cI, which has the A2 repressor gene (cI) integrated into the genome, was completely resistant and able to ferment milk whether phage was present or not. In addition, viable phages were eliminated from the milk, probably through adsorption to the cell wall. Finally, the integration of cI in the genome resulted in a stable resistance phenotype, being unnecessary selective pressure during milk fermentation.

Animals↗
PubMed1999

Molecular analysis in familial neurohypophyseal diabetes insipidus: early diagnosis of an asymptomatic carrier.

Familial neurohypophyseal diabetes insipidus (FNDI) is an inherited deficiency of the hormone arginine vasopressin (AVP) and is transmitted as an autosomal dominant trait. In the present study we have analyzed the AVP-neurophysin II (AVP-NPII) gene in a Spanish kindred. Studies were performed on seven members (four clinically affected) of the family. Patients were diagnosed at the Hospital Universitario Gregorio Marañón (Madrid, Spain). The entire coding region of the AVP-NPII gene of all family members was amplified by PCR and sequenced. All affected individuals presented a missense mutation (G1757-->A) that replaces glycine at position 23 with arginine within the NPII domain. The substitution was confirmed by restriction endonuclease analysis and was present in heterozygosis. Additionally, one of the asymptomatic relatives (a girl 8 months old at the time of study) was identified as carrier of the same mutation and developed the disease 3 months later. The alteration found in the second exon of the gene in this family seems to be responsible for the disease, as all individuals harboring the mutation had been previously diagnosed or have eventually developed FNDI. Identification of the molecular defect underlying FNDI in affected families is a powerful tool for early asymptomatic diagnosis in infants.

Arginine Vasopressin↗
PubMed1999

The beneficial effects of weekly low-dose vitamin A supplementation on acute lower respiratory infections and diarrhea in Ecuadorian children.

BACKGROUND: Previous studies of large-dose vitamin A supplementation on respiratory morbidity have produced conflicting results in a variety of populations. The influence of malnutrition has not been examined in the majority of these trials. We hypothesized that weekly low-dose vitamin A supplementation would prevent respiratory and diarrheal disease morbidity and that malnutrition might influence the efficacy of vitamin A supplementation. METHODS: In a randomized, double-blind, placebo-controlled field trial of 400 children, 6 to 36 months of age in a high Andean urban slum, half of the children received 10 000 IU of vitamin A weekly and half received placebo for 40 weeks. Children were visited weekly at home by physicians and assessed for acute diarrheal disease and acute respiratory infections. RESULTS: Acute diarrheal disease and acute respiratory infection did not differ globally or by severity between supplement-treated and placebo groups. However, the incidence of acute lower respiratory infection (ALRI) was significantly lower in underweight (weight-for-age z score [WAZ] <-2 SD) supplement-treated children than in underweight children on placebo (8.5 vs 22.3 per 10(3) child-weeks; rate ratio: 0.38 [95% CI: 0.17-0.85]). ALRI incidence was significantly higher in normal-weight (WAZ >-2 SD) supplement-treated children than in normal-weight children on placebo (9.8 vs 4.4 per 10(3) child-weeks; rate ratio: 2.21 [95% CI: 1.24-3.93]). By logistic regression analysis the risk of ALRI was lower in underweight supplement-treated children than in underweight children on placebo (point estimate 0.148 [95% CI: 0.034-0.634]). In contrast, risk of ALRI was higher in normal-weight supplement-treated children (WAZ >-1 SD to mean) than in normal-weight children on placebo in the same WAZ stratum (point estimate: 2.51 [95% CI: 1.24-5.05]). The risk of severe diarrhea was lower in supplement-treated children 18 to 23 months of age than in children on placebo in this age group (point estimate: 0.26 [95% CI: 0.06-1.00]). CONCLUSIONS: Weekly low-dose (10 000 IU) vitamin A supplementation in a region of subclinical deficiency protected underweight children from ALRI and paradoxically increased ALRI in normal children with body weight over -1 SD. Protection from severe diarrhea was consistent with previous trials. Additional research is warranted to delineate potential beneficial and detrimental interactions between nutritional status and vitamin A supplementation regarding ALRI.

Acute Disease↗
PubMed1999

[Recurrent cerebral embolism as the main sign of atrial myxoma].

Atrial myxomas (AM) are the most frequent cardiac tumors. Between 25-45% of the cases present neurologic manifestations, generally owing to cerebral embolic infarcts or intracranial haemorrhages. Cerebral embolism can precede cardiac or constitutional symptoms, but recurrent embolisms as the only disturbance are infrequent. We present the case of two patients with 66 and 70 years that suffered recurrent cerebral embolisms as the only manifestation of a left AM. Magnetic resonance (MR) studies showed several isquemic infarcts in different vascular territories. Echocardiagrams showed the presence of heterogeneous masses in left atrial that suggested AM. These were removed in both cases and the diagnosis of AM was confirmed by anatomopathologic exam. The presence of recurrent isquemic episodes in different cerebral territories must point the diagnosis to a cardioembolic source. AM must be taken into account in these cases, despite the lack of constitutional or cardiac symptoms, older age or concomitant carotid pathology.

Aged↗
PubMed1999

[Thyroid tumors in childhood].

The thyroid pathology in the paediatric population represents 5% of the total and 1.2% only thyroid pathology correspond to the infantile solitary thyroid nodules. Most of them are asymptomatic and as only sign an increase of volume is observed in the neck. Always we have to ask about the family history because the possibility of medullary carcinoma related with multiple endocrine neoplasias should be investigated (a patient of our series). The thyroid tumor represents 0.5% of all the tumors and of these 10% is in younger than 21 years old. We present 13 patients with thyroid pathology that have required surgical treatment, since 1983 to 1997. Five papillary carcinomas (ages: 7 to 14 years old) that started with a cervical nodule, normal thyroid function and a case of medullary carcinoma, in a multiple endocrine neoplasia (MEN II 2A). In the 5 cases of carcinoma papillary we were carried out total thyroidectomy and later on, postoperative ablative dose of 131I was administered. In the case of the girl with medullary carcinoma was carried out a total tumorectomy and lymph node excision. Finally, seven patients with nodule thyroid were thyroid benign tumors (benign 6 adenomas and 1 cyst colloid, ages: 8 to 15 years old). In all of them we were carried out total surgical excision of the thyroid nodules. Our protocol of study of nodule thyroid includes: 1) thyroid gammagraphy to know the intensity of reception of the isotope; 2) cervical ultrasound; and 3) biopsy or cytopathology of fine needle aspiration of the thyroid gland in children that it dissuades to base the surgical strategy on this test.

Adenoma↗
PubMed1999

[Comparative structural study of the glial blastomas of the central nervous system].

The objective of our work is to compare 2 diagnostics methods and demonstrate the similarities of the different Central Nervous System Glial Tumor Classifications. Immuno-marking techniques for gliofibrilar acid protein (GFAP), and special silver impregnations to compare the results according to the last histogenetic interpretations were used. 95 Gliomas were studied with hematoxiline-eosine and silver techniques, and in 58 randomized selected cases the technique for GFAP was also used. Both methods showed the same results in the diagnosis of Glial Tumors whose cells possess gliofibrils: Glioepitelioma (Ependymoma), Glioblastoma, Astroblastoma, and Astrocytoma. In the Oligodendrioglomas whose cells possess microtubules but not gliofibrils, the silver techniques marked these cells and their prolongations while the technique for GFAP did not. Regarding Gliomas, there are similarities by comparing the Del Río Ortega-Polak classification with those of the WHO and other authors. There are differences only in the "names" of some tumors or in their histogenetic interpretation, which are not substantial and are confined to the "Polar Espongioblastoma" and "Gliosarcoma". Therefore, we think that the recognition of the Del Río Hortega-Polak classification is justified.

Brain Neoplasms↗
PubMed1999

[Tumors with rhabdomyoblasts and neuroblasts].

A metallic impregnation technique, Del Río Hortega's double impregnation, to evidence neuroblasts and rhabdomyoblasts, with recommendations as to the times of impregnation to obtains better results is evaluated. The images obtained are highly demonstrative both of the embryo elements of the primitive mesenchyma from myoblast, myotube, a rhabdomyoblastic ribbon cell with transverse streaks to the neoplastic elements of this lineage and to the neuroblasts with their extensions. The study material includes a renal tumor of Wilms with rhabdomyoblasts and neuroblasts and a cerebellum neuroblastoma with a rhabdomyoblastic element. These injuries are considered dysembryoplasic. We also studied two botryoid embryo rhabdomyosarcomas, begin one or them unusually found in a menopausic woman, two Müller mixed tumors of the uterus and Fallopian tubes, a rhabdomyoma in pharynx and three human embryos from aborted material between 5 and 13 weeks old. We emphasize the use of double impregnation to study rhabdomyoblasts and neuroblasts. In rhabdomyosarcomas, structures and elements similar to those of the embryo stage--racketoid and ribbon cells, myotubes and rhabdomyoblasts--can be observed. The tumor of Wilms is a dysembryoplasic tumor composed of renal blastem where we have found rhabdomyoblasts and neuroblasts. In the cerebellum neuroblastoma we observe rhabdomyoblasts with certain organism (ectomesenchyma). Finally, we describe a rather infrequent case of a cervix botryoid rhabdomyosarcoma of a menopausic woman.

Adolescent↗
PubMed1998

A computer model for the analysis of DNA replication intermediates by two-dimensional agarose gel electrophoresis.

We present a computer model to predict the patterns expected for the replication intermediates (RIs) of DNA fragments analyzed by neutral/neutral two-dimensional (2D) agarose gel electrophoresis. The model relies on the mode of replication (uni- or bi-directional), the electrophoretic mobility of linear DNA fragments and the retardation caused by the three-dimensional shape of non-linear molecules. The utility of this model is demonstrated with two examples: replication analysis of the plasmids pBR322 and pHH5.8 in Escherichia coli after digestions with EcoRI and HindIII, respectively.

Computer Simulation↗